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Sample records for beam position monitor

  1. Magnetic beam position monitor

    SciTech Connect

    Varfolomeev, A.A.; Ivanchenkov, S.N.; Khlebnikov, A.S.

    1995-12-31

    Many nondestructive beam position monitors are known. However, these devices can not be used for DC particle beam diagnostics. We investigated a method of beam diagnostics applicable for the operative control of DC high power e-beam inside closed waveguide. A design of the detector for determination of{open_quote} center of mass {close_quote} position of DC particle beam was developed. It was shown that the monitor can be used as a nondestructive method for the beam position control in resonators. Magnetic field of the particle beam outside a resonator is used. The detector consists of the steel yokes and magnetic field sensors. The sensors measure magnetic fluxes in the steel yokes fixed outside the resonator. When the particle beam changes its position, these magnetic fluxes also change. Beam displacement sensitivity of the monitor depends on the steel yoke dimensions. The detector sensitivity is equal to 1 Gauss/mm for the conditions adequate to the FOM-FEM project.

  2. Photon beam position monitor

    DOEpatents

    Kuzay, Tuncer M.; Shu, Deming

    1995-01-01

    A photon beam position monitor for use in the front end of a beamline of a high heat flux and high energy photon source such as a synchrotron radiation storage ring detects and measures the position and, when a pair of such monitors are used in tandem, the slope of a photon beam emanating from an insertion device such as a wiggler or an undulator inserted in the straight sections of the ring. The photon beam position monitor includes a plurality of spaced blades for precisely locating the photon beam, with each blade comprised of chemical vapor deposition (CVD) diamond with an outer metal coating of a photon sensitive metal such as tungsten, molybdenum, etc., which combination emits electrons when a high energy photon beam is incident upon the blade. Two such monitors are contemplated for use in the front end of the beamline, with the two monitors having vertically and horizontally offset detector blades to avoid blade "shadowing". Provision is made for aligning the detector blades with the photon beam and limiting detector blade temperature during operation.

  3. Photon beam position monitor

    DOEpatents

    Kuzay, T.M.; Shu, D.

    1995-02-07

    A photon beam position monitor is disclosed for use in the front end of a beamline of a high heat flux and high energy photon source such as a synchrotron radiation storage ring detects and measures the position and, when a pair of such monitors are used in tandem, the slope of a photon beam emanating from an insertion device such as a wiggler or an undulator inserted in the straight sections of the ring. The photon beam position monitor includes a plurality of spaced blades for precisely locating the photon beam, with each blade comprised of chemical vapor deposition (CVD) diamond with an outer metal coating of a photon sensitive metal such as tungsten, molybdenum, etc., which combination emits electrons when a high energy photon beam is incident upon the blade. Two such monitors are contemplated for use in the front end of the beamline, with the two monitors having vertically and horizontally offset detector blades to avoid blade ''shadowing''. Provision is made for aligning the detector blades with the photon beam and limiting detector blade temperature during operation. 18 figs.

  4. Beam position monitor

    DOEpatents

    Alkire, Randy W.; Rosenbaum, Gerold; Evans, Gwyndaf

    2003-07-22

    An apparatus for determining the position of an x-ray beam relative to a desired beam axis. Where the apparatus is positioned along the beam path so that a thin metal foil target intersects the x-ray beam generating fluorescent radiation. A PIN diode array is positioned so that a portion of the fluorescent radiation is intercepted by the array resulting in an a series of electrical signals from the PIN diodes making up the array. The signals are then analyzed and the position of the x-ray beam is determined relative to the desired beam path.

  5. LEDA BEAM DIAGNOSTICS INSTRUMENTATION: BEAM POSITION MONITORS

    SciTech Connect

    D. BARR; ET AL

    2000-05-01

    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.

  6. Tevatron beam position monitor upgrade

    SciTech Connect

    Wolbers, Stephen; Banerjee, B.; Barker, B.; Bledsoe, S.; Boes, T.; Bowden, M.; Cancelo, G.; Forster, B.; Duerling, G.; Haynes, B.; Hendricks, B.; Kasza, T.; Kutschke, R.; Mahlum, R.; Martens, M.; Mengel, M.; Olson, M.; Pavlicek, V.; Pham, T.; Piccoli, L.; Steimel, J.; /Fermilab

    2005-05-01

    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 1980's, 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. A machine protection beam position monitor system

    SciTech Connect

    Medvedko, E.; Smith, S.; Fisher, A.

    1998-12-10

    Loss of the stored beam in an uncontrolled manner can cause damage to the PEP-II B Factory. We describe here a device which detects large beam position excursions or unexpected beam loss and triggers the beam abort system to extract the stored beam safely. The bad-orbit abort trigger beam position monitor (BOAT BPM) generates a trigger when the beam orbit is far off the center (>20 mm), or rapid beam current loss (dI/dT) is detected. The BOAT BPM averages the input signal over one turn (136 kHz). AM demodulation is used to convert input signals at 476 MHz to baseband voltages. The detected signal goes to a filter section for suppression of the revolution frequency, then on to amplifiers, dividers, and comparators for position and current measurements and triggering. The derived current signal goes to a special filter, designed to perform dI/dT monitoring at fast, medium, and slow current loss rates. The BOAT BPM prototype test results confirm the design concepts.

  8. A machine protection beam position monitor system

    SciTech Connect

    Medvedko, E.; Smith, S.; Fisher, A.

    1998-12-01

    Loss of the stored beam in an uncontrolled manner can cause damage to the PEP-II {ital B} Factory. We describe here a device which detects large beam position excursions or unexpected beam loss and triggers the beam abort system to extract the stored beam safely. The bad-orbit abort trigger beam position monitor (BOAT BPM) generates a trigger when the beam orbit is far off the center ({gt}20 mm), or rapid beam current loss (dI/dT) is detected. The BOAT BPM averages the input signal over one turn (136 kHz). AM demodulation is used to convert input signals at 476 MHz to baseband voltages. The detected signal goes to a filter section for suppression of the revolution frequency, then on to amplifiers, dividers, and comparators for position and current measurements and triggering. The derived current signal goes to a special filter, designed to perform dI/dT monitoring at fast, medium, and slow current loss rates. The BOAT BPM prototype test results confirm the design concepts. {copyright} {ital 1998 American Institute of Physics.}

  9. Transverse Beam Size Effects in Beam Position Monitors

    NASA Astrophysics Data System (ADS)

    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.

  10. EFFECTS OF TRANSFERSE BEAM SIZE IN BEAM POSITIONS MONITORS

    SciTech Connect

    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.

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

    SciTech Connect

    Kurennoy, 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 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. Beam Position Monitor System for PEP II

    SciTech Connect

    Smith, Stephen R.; Aiello, G.Roberto; Hendrickson, Linda J.; Johnson, Ronald G.; Mills, Mark R.; Olsen, Jeff J.; /SLAC

    2011-09-12

    We describe the beam position monitor system built for PEP-II, the B-factory at SLAC. The system reports beam position for bunches of between 5 x 10{sup 8} and 8 x 10{sup 10} electron charges, either singly or as continuous streams of bunches every 4.2 ns. Resolution at full charge is to be better than 10 microns in a single turn. Higher resolution is available via on-board multi-turn averaging. The position signal is processed in a 20 MHz bandwidth around 952 MHz. This bandwidth, rather broader than that typical of RF position monitors, allows good resolution for low charge single bunches. Additional novel features include stringent control of return losses in order to minimize cross-talk between nearby bunches which may contain very different charges. The digitizing electronics is multiplexed between the two PEP-II storage rings. Design, construction, and installation experience, as well as first results with beam are presented.

  13. Comparison of beam-position-transfer functions using circular beam-position monitors

    SciTech Connect

    Gilpatrick, J.D.

    1997-10-01

    A cylindrical beam-position monitor (BPM) used in many accelerator facilities has four electrodes on which beam-image currents induce bunched-beam signals. These probe-electrode signals are geometrically configured to provide beam-position information about two orthogonal axes. An electronic processor performs a mathematical transfer function (TF) on these BPM-electrode signals to produce output signals whose time-varying amplitude is proportional to the beam`s vertical and horizontal position. This paper will compare various beam-position TFs using both pencil beams and will further discuss how diffuse beams interact with some of these TFs.

  14. Fermilab Main Injector Beam Position Monitor Upgrade

    SciTech Connect

    Banerjee, B.; Barker, W.; Bledsoe, S.; Boes, T.; Briegel, C.; Capista, D.; Deuerling, G.; Dysert, R.; Forster, R.; Foulkes, S.; Haynes, W.; Hendricks, B.; Kasza, T.; Kutschke, R.; Marchionni, A.; Olson, M.; Pavlicek, V.; Piccoli, L.; Prieto, P.; Rapisarda, S.; Saewert, A.; /Fermilab

    2006-05-01

    An upgrade of the Beam Position Monitor (BPM) signal processing and data acquisition system for the Fermilab Main Injector is described. The Main Injector is a fast cycling synchrotron that accelerates protons or antiprotons from 8 to 150 GeV. Each Main Injector cycle can have a totally different magnet ramp, RF frequency configuration, beam bunch structure, and injection/extraction pattern from the previous cycle. The new BPM system provides the capabilities and flexibility required by the dynamic and complex machine operations. The system offers measurement capability in the 2.5 MHz and 53 MHz channels to detect the range of bunch structures for protons and antiprotons in both wideband (turn-by-turn) and narrowband (closed-orbit) modes. The new BPM read-out system is based on the digital receiver concept and is highly configurable, allowing the signal processing of nearly all Main Injector beam conditions, including the detection of individual batches. An overview of the BPM system in the Main Injector operating environment, some technology details and first beam measurements are presented.

  15. Fermilab Main Injector Beam Position Monitor Upgrade

    SciTech Connect

    Banerjee, B.; Barker, W.; Bledsoe, S.; Boes, T.; Briegel, C.; Capista, D.; Deuerling, G.; Dysert, R.; Forster, R.; Foulkes, S.; Haynes, W.; Hendricks, B.; Kasza, T.; Kutschke, R.; Marchionni, A.; Olson, M.; Pavlicek, V.; Piccoli, L.; Prieto, P.; Rapisarda, S.

    2006-11-20

    An upgrade of the Beam Position Monitor (BPM) signal processing and data acquisition system for the Fermilab Main Injector is described. The Main Injector is a fast cycling synchrotron that accelerates protons or antiprotons from 8 to 150 GeV, Each Main Injector cycle can have a totally different magnet ramp, RF frequency configuration, beam bunch structure, and injection/extraction pattern from the previous cycle. The new BPM system provides the capabilities and flexibility required by the dynamic and complex machine operations. The system offers measurement capability in the 2.5 MHz and 53 MHz channels to detect the range of bunch structures for protons and antiprotons in both wideband (turn-by-turn) and narrowband (closed-orbit) modes. The new BPM read-out system is based on the digital receiver concept and is highly configurable, allowing the signal processing of nearly all Main Injector beam conditions, including the detection of individual batches. An overview of the BPM system in the Main Injector operating environment, some technology details and first beam measurements are presented.

  16. A Two Bunch Beam Position Monitor

    SciTech Connect

    Medvedko, E.; Aiello, R.; Smith, S.; /SLAC

    2011-09-12

    A new beam position monitor digitizer module has been designed, tested and tuned at SLAC. This module, the electron-positron beam position monitor (epBPM), measures position of single electron and positron bunches for the SLC, LINAC, PEPII injections lines and final focus. The epBPM has been designed to improve resolution of beam position measurements with respect to existing module and to speed feedback correction. The required dynamic range is from 5 x 10{sup 8} to 10{sup 11} particles per bunch (46dB). The epBPM input signal range is from {+-}2.5 mV to {+-}500 mV. The pulse-to-pulse resolution is less than 2 {mu}m for 5 x 10{sup 10} particles per bunch for the 12 cm long striplines, covering 30{sup o} at 9 mm radius. The epBPM module has been made in CAMAC standard, single width slot, with SLAC type timing connector. 45 modules have been fabricated. The epBPM module has four input channels X{sup +}, X{sup -}, Y{sup +}, Y{sup -} (Fig. 1), named to correspond with coordinates of four striplines - two in horizontal and two in vertical planes, processing signals to the epBPM inputs. The epBPM inputs are split for eight signal processing channels to catch two bunches, first - the positron, then the electron bunch in one cycle of measurements. The epBPM has internal and external trigger modes of operations. The internal mode has two options - with or without external timing, catching only first bunch in the untimed mode. The epBPM has an on board calibration circuit for measuring gain of the signal processing channels and for timing scan of programmable digital delays to synchronize the trigger and the epBPM input signal's peak. There is a mode for pedestal measurements. The epBPM has 3.6 {mu}s conversion time.

  17. Signal processing for beam position monitors

    NASA Astrophysics Data System (ADS)

    Vismara, Giuseppe

    2000-11-01

    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 circuitry. In conclusion, an application example will show how to choose the correct solution for a particular case.

  18. NSLS-II RF BEAM POSITION MONITOR

    SciTech Connect

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    SciTech Connect

    Kurennoy, S.

    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.

  1. A photon beam position monitor for SSRL beamline 9

    SciTech Connect

    Cerino, J.A.; Rabedeau, T.; Bowen, W.

    1995-10-01

    We present here the concept of a simple one dimensional photon beam position monitor for use with high power synchrotron radiation beams. It has micron resolution, reasonable linearity in an inexpensive design. Most important, is its insensitivity to diffusely scattered low energy radiation from components upstream of the monitor.

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

    PubMed

    Samadi, Nazanin; Bassey, Bassey; Martinson, Mercedes; Belev, George; Dallin, Les; de Jong, Mark; Chapman, Dean

    2015-07-01

    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 in position and angle at the source point. The results are comparable with other methods of beam position measurement and indicate that such a system is feasible in situations where part of the synchrotron beam can be used for the phase-space measurement.

  3. Beam Position and Phase Monitor - Wire Mapping System

    SciTech Connect

    Watkins, Heath A; Shurter, Robert B.; Gilpatrick, John D.; Kutac, Vincent G.; Martinez, Derwin

    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.

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

    SciTech Connect

    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.

  5. MULTI - MILLION - TURN BEAM POSITION MONITORS FOR RHIC.

    SciTech Connect

    SATOGATA,T.CAMERON,P.CERNIGLIA,P.CUPOLO,J.DAWSON,CDEGEN,CMEAD,JVETTER,K

    2003-05-12

    During the RHIC 2003 run, two beam position monitors (BPMs) in each transverse plane in the RHIC blue ring were upgraded with high-capacity mezzanine cards. This upgrade provided these planes with the capability to digitize up to 128 million consecutive turns of RHIC beam, or almost 30 minutes of continuous beam centroid phase space evolution for a single RHIC bunch. This paper describes necessary hardware and software changes and initial system performance. We discuss early uses and results for diagnosis of coherent beam oscillations, turn-by-turn (TBT) acquisition through a RHIC acceleration ramp, and ac-dipole nonlinear dynamics studies.

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

    PubMed Central

    Samadi, Nazanin; Bassey, Bassey; Martinson, Mercedes; Belev, George; Dallin, Les; de Jong, Mark; Chapman, Dean

    2015-01-01

    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 in position and angle at the source point. The results are comparable with other methods of beam position measurement and indicate that such a system is feasible in situations where part of the synchrotron beam can be used for the phase-space measurement. PMID:26134798

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

    SciTech Connect

    Decker, G.; Chung, Youngjoo.

    1991-01-01

    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.

  8. Video-based beam position monitoring at CHESS

    NASA Astrophysics Data System (ADS)

    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.

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

    SciTech Connect

    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, Berkeley /LBL, Berkeley /Cambridge U. /Royal Holloway, U. of London /Cornell U., LNS /LLNL, Livermore /University Coll. London /SLAC /Caltech /KEK, Tsukuba

    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.

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

    SciTech Connect

    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.

  11. Noise estimation of beam position monitors at RHIC

    SciTech Connect

    Shen, X.; Bai, M.; Lee, S. Y.

    2014-02-10

    Beam position monitors (BPM) are used to record the average orbits and transverse turn-by-turn displacements of the beam centroid motion. The Relativistic Hadron Ion Collider (RHIC) has 160 BPMs for each plane in each of the Blue and Yellow rings: 72 dual-plane BPMs in the insertion regions (IR) and 176 single-plane modules in the arcs. Each BPM is able to acquire 1024 or 4096 consecutive turn-by-turn beam positions. Inevitably, there are broadband noisy signals in the turn-by-turn data due to BPM electronics as well as other sources. A detailed study of the BPM noise performance is critical for reliable optics measurement and beam dynamics analysis based on turn-by-turn data.

  12. Beam Position-Phase Monitors for SNS Linac

    NASA Astrophysics Data System (ADS)

    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.

  13. A button - type beam position monitor design for TARLA facility

    NASA Astrophysics Data System (ADS)

    Gündoǧan, M. Tural; Kaya, ć.; Yavaş, Ö.

    2016-03-01

    Turkish Accelerator and Radiation Laboratory in Ankara (TARLA) facility is proposed as an IR FEL and Bremsstrahlung facility as the first facility of Turkish Accelerator Center (TAC). TARLA is essentially proposed to generate oscillator mode FEL in 3-250 microns wavelengths range, will consist of normal conducting injector system with 250 keV beam energy, two superconducting RF accelerating modules in order to accelerate the beam 15-40 MeV. The TARLA facility is expected to provide two modes, Continuous wave (CW) and pulsed mode. Longitudinal electron bunch length will be changed between 1 and 10 ps. The bunch charge will be limited by 77pC. The design of the Button-type Beam Position Monitor for TARLA IR FEL is studied to operate in 1.3 GHz. Mechanical antenna design and simulations are completed considering electron beam parameters of TARLA. Ansoft HFSS and CST Particle Studio is used to compare with results of simulations.

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

    SciTech Connect

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

    2005-09-12

    International Linear Collider (ILC) interaction region beam sizes and component position stability requirements will be as small as a few nanometers. It is important to the ILC design effort to demonstrate that these tolerances can be achieved - ideally using beam-based stability measurements. It has been estimated that RF cavity beam position monitors (BPMs) could provide position measurement resolutions of less than one nanometer and could form the basis of the desired beam-based stability measurement. We have developed a high resolution RF cavity BPM system. A triplet of these BPMs has been installed in the extraction line of the KEK Accelerator Test Facility (ATF) for testing with its ultra-low emittance beam. A metrology system for the three BPMs was recently installed. This system employed optical encoders to measure each BPM's position and orientation relative to a zero-coefficient of thermal expansion carbon fiber frame and has demonstrated that the three BPMs behave as a rigid-body to less than 5 nm. To date, we have demonstrated a BPM resolution of less than 20 nm over a dynamic range of +/- 20 microns.

  15. Beam position monitor design for a third generation light source

    NASA Astrophysics Data System (ADS)

    Chen, Zhichu; Leng, Yongbin; Ye, Kairong; Zhao, Guobi; Yuan, Renxian

    2014-11-01

    The measurement of the beam orbit plays a very important role in particle accelerators. The button-type beam position monitor (BPM) was designed for the Shanghai Synchrotron Radiation Facility to reduce the impedances and to guarantee a high resolution of the measurement. Position resolution, beam impedance, higher-order mode, and impedance matching have been studied during the design based on the physical parameters of the storage ring at the Shanghai Synchrotron Radiation Facility. Meanwhile, an analytic formula of the BPM broadband impedance was derived based on a resistor-capacitor equivalent circuit. Thus, the impedance of the BPM could be analyzed quantitatively by simply measuring the capacitance of the electrode. This formula had been verified by comparing the results of the calculations of the formula and the simulations in MAFIA.

  16. Beam Position Monitoring in the CSU Accelerator Facility

    NASA Astrophysics Data System (ADS)

    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.

  17. Integral window/photon beam position monitor and beam flux detectors for x-ray beams

    DOEpatents

    Shu, Deming; Kuzay, Tuncer M.

    1995-01-01

    A monitor/detector assembly in a synchrotron for either monitoring the position of a photon beam or detecting beam flux may additionally function as a vacuum barrier between the front end and downstream segment of the beamline in the synchrotron. A base flange of the monitor/detector assembly is formed of oxygen free copper with a central opening covered by a window foil that is fused thereon. The window foil is made of man-made materials, such as chemical vapor deposition diamond or cubic boron nitrate and in certain configurations includes a central opening through which the beams are transmitted. Sensors of low atomic number materials, such as aluminum or beryllium, are laid on the window foil. The configuration of the sensors on the window foil may be varied depending on the function to be performed. A contact plate of insulating material, such as aluminum oxide, is secured to the base flange and is thereby clamped against the sensor on the window foil. The sensor is coupled to external electronic signal processing devices via a gold or silver lead printed onto the contact plate and a copper post screw or alternatively via a copper screw and a copper spring that can be inserted through the contact plate and coupled to the sensors. In an alternate embodiment of the monitor/detector assembly, the sensors are sandwiched between the window foil of chemical vapor deposition diamond or cubic boron nitrate and a front foil made of similar material.

  18. New generation electronics applied to beam position monitors

    NASA Astrophysics Data System (ADS)

    Unser, Klaus B.

    1997-01-01

    Cellular telephones and global positioning system (GPS) satellite receivers are examples of modern rf engineering. Taking some inspiration from those designs, a precision signal-processor module for beam position monitors was developed. It features a heterodyne receiver (100 MHz to 1 GHz) with more than 90 dB dynamic range. Four multiplexed input channels are able to resolve signal differences lower than 0.0005 dB with good long-term stability. This corresponds to sub-micron resolution when used with a beam position pick-up with 40 mm free aperture. The paper concentrates on circuit design and modern dynamic testing methods, used first during development and later for production tests. The frequency synthesizer of the local oscillator, the phase-locked synchronous detector, and the low-noise preamplifier with automatic gain control are discussed. Other topics are design for immunity to electromagnetic interference to ensure reliable operation in an accelerator environment.

  19. Correlation study of a beam-position monitor and a photon-beam-position monitor in the PLS-II

    NASA Astrophysics Data System (ADS)

    Kim, Changbum; Shin, Seunghwan; Hwang, Ilmoon; Lee, Byung-Joon; Joo, Young-Do; Ha, Taekyun; Yoon, Jong Chel; Kim, Ghyung Hwa; Kim, Mungyung; Lee, Eun Hee; Kim, Ilyou; Huang, Jung-Yun

    2015-01-01

    The beam stability is one of the most important issues for the user service of the synchrotron radiation facility. After the upgrade of the Pohang Light Source (PLS-II), the electron-beam orbit is maintained within a root-mean-squred (rms) 1- μm range by using an orbit feedback system. However, that does not guarantee the radiation stability at the end of the beamline because unknown factors, such as focusing mirrors and double-crystal monocrometers, are present in the beamline. As a first step to solve this problem, photon-beam-position monitors (PBPMs) are installed in the front ends of the beamline to monitor the radiation stability. If the radiation is stable at the starting point of the beamline, we can move to the other components downstream that make the radiation unstable. In this paper, a correlation study will be presented between the beam-position monitor (BPM) and the PBPM. In addition, the effect of the orbit feedback system on the correlation will be described.

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

    NASA Astrophysics Data System (ADS)

    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.

  1. A two-bunch beam position monitor performance evaluation

    SciTech Connect

    Traller, Robert; Medvedko, Evgeny; Smith, Steve; Aiello, Roberto

    1998-12-10

    New beam position processing electronics for the Linear Accelerator allow faster feedback and processing of both positron and electron bunch positions in a single machine pulse. More than 30 electron-positron beam position monitors (epBPMs) have been installed at SLAC in various applications and have met all design requirements. The SLC production electron bunch follows the positron bunch down the linac separated by 58.8 nS. The epBPM measures the position of both bunches with an accuracy of better than 5 {mu}m at nominal operating intensities. For SLC, the epBPMs have measured the position of bunches consisting of from 1 to 8x10{sup 10} particles per bunch. For PEP-II (B Factory) injection, epBPMs have been used with larger electrodes and several BPMs have been combined on a single cable set. The signals are separated for measurement in the epBPM by timing. In PEP-II injection we have measured the position of bunches of as little as 2x10{sup 9} particles per bunch. To meet the demands of SLC and PEP-II injection, the epBPM has been designed with three triggering modes: 1. As a self-triggering detector, it can trigger off the beam and hold the peak signal until read out by the control program. 2. The gated mode uses external timing signals to gate the beam trigger. 3. The external trigger mode uses the external timing signals offset with internal vernier delays to precisely catch peak signals in noisy environments. Finally, the epBPM also has built-in timing verniers capable of nulling errors in cable set fabrication and differences in channel-to-channel signal delay. Software has made all this functionality available through the SLC control system.

  2. Cavity Beam Position Monitor System for ATF2

    SciTech Connect

    Boogert, Stewart; Boorman, Gary; Swinson, Christina; Ainsworth, Robert; Molloy, Stephen; Aryshev, Alexander; Honda, Yosuke; Tauchi, Toshiaki; Terunuma, Nobuhiro; Urakawa, Junji; Frisch, Josef; May, Justin; McCormick, Douglas; Nelson, Janice; Smith, Tonee; White, Glen; Woodley, Mark; Heo, Ae-young; Kim, Eun-San; Kim, Hyoung-Suk; 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.

  3. Architecture of a silicon strip beam position monitor

    NASA Astrophysics Data System (ADS)

    Angstadt, R.; Cooper, W.; Demarteau, M.; Green, J.; Jakubowski, S.; Prosser, A.; Rivera, R.; Turqueti, M.; Utes, M.; Cai, X.

    2010-12-01

    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 of triggered events and temperature data to an analysis computer over gigabit Ethernet links.

  4. The new Tevatron beam position monitor front-end software

    SciTech Connect

    Piccoli, Luciano; Votava, Margaret; Zhang, Dehong; /Fermilab

    2005-05-01

    The Tevatron is a proton anti-proton accelerator collider operating at the Fermi National Accelerator Laboratory. The machine is currently delivering beam for the CDF and D0 experiments, which expect increasing luminosity until the conclusion of Run II, planned for 2009. The Laboratory defined a plan for achieving higher luminosity, and one of the tasks is the upgrade of the accelerator's beam position monitor (BPM). The Tevatron was built during the early eighties and some of its control systems, including the BPMs, are still the original ones. This paper describes the front-end software of the Tevatron BPM upgrade, from the requirements to the implementation, and the underlying hardware setup. The front-end software designed is presented, emphasizing its modularity and reusability, allowing it to be applied to other Fermilab machines.

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

    NASA Astrophysics Data System (ADS)

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

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

  8. Digital Beam Position Monitor for the Happex Experiment

    SciTech Connect

    S.R. Kauffman; H. Dong; A. Freyberger; L. Kaufman; J. Musson

    2005-05-16

    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.

  9. Digital beam position monitor for the HAPPEX experiment

    SciTech Connect

    Sherlon Kauffman; John Musson; Hai Dong; Lisa Kaufman; Arne Freyberger

    2005-05-01

    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.

  10. Transmission-mode diamond white-beam position monitor at NSLS

    SciTech Connect

    Muller E. M.; Heroux A.; Smedley, J.; Bohon, J.; Yang, X.; Gaowei, M.; Skinner, J.; De Geronimo, G.; Sullivan, M.; Allaire, M.; Keister, J. W.; Berman, L.

    2012-05-01

    Two transmission-mode diamond X-ray beam position monitors installed at National Synchrotron Light Source (NSLS) beamline X25 are described. Each diamond beam position monitor is constructed around two horizontally tiled electronic-grade (p.p.b. nitrogen impurity) single-crystal (001) CVD synthetic diamonds. The position, angle and flux of the white X-ray beam can be monitored in real time with a position resolution of 500 nm in the horizontal direction and 100 nm in the vertical direction for a 3 mm x 1 mm beam. The first diamond beam position monitor has been in operation in the white beam for more than one year without any observable degradation in performance. The installation of a second, more compact, diamond beam position monitor followed about six months later, adding the ability to measure the angular trajectory of the photon beam.

  11. Applying EVM principles to Tevatron Beam Position Monitor Project

    SciTech Connect

    Banerjee, Bakul; /Fermilab

    2005-08-01

    At Fermi National Accelerator Laboratory (Fermilab), the Tevatron high energy particle collider must meet the increasing scientific demand of higher beam luminosity. To achieve this higher luminosity goal, U. S. Department of Energy (DOE) sponsored a major upgrade of capabilities of Fermilab's accelerator complex that spans five years and costs over fifty million dollars. Tevatron Beam Position Monitor (BPM) system upgrade is a part of this project, generally called RunII upgrade project. Since the purpose of the Tevatron collider is to detect the smashing of proton and anti-protons orbiting the circular accelerator in opposite directions, capability to detect positions of both protons and antiprotons at a high resolution level is a desirable functionality of the monitoring system. The original system was installed during early 1980s, along with the original construction of the Tevatron. However, electronic technology available in 1980s did not allow for the detection of significantly smaller resolution of antiprotons. The objective of the upgrade project is to replace the existing BPM system with a new system utilizing capabilities of modern electronics enhanced by a front-end software driven by a real-time operating software. The new BPM system is designed to detect both protons and antiprotons with increased resolution of up to an order of magnitude. The new system is capable of maintaining a very high-level of data integrity and system reliability. The system consists of 27 VME crates installed at 27 service buildings around the Tevatron ring servicing 236 beam position monitors placed underground, inside the accelerator tunnel. Each crate consists of a single Timing Generator Fanout module, custom made by Fermilab staff, one MVME processor card running VxWorks 5.5, multiple Echotek Digital Receiver boards complimented by custom made Filter Board. The VxWorks based front-end software communicates with the Main Accelerator Control software via a special

  12. Beam position and total current monitor for heavy ion fusion beams

    SciTech Connect

    Berners, D.; Reginato, L.L.

    1992-10-01

    Heavy Ion Fusion requires moderate currents, 1-10A, for a duration of about 1 {mu}s. For accurate beam transport, the center of charge must be located to within {plus_minus} 100 {mu}m. Beam position and intensity may be excited at frequencies approaching 10 MHz, and the monitoring system must have adequate bandwidth to respond at these frequencies. We have modified the Rogowski technique by using distributed reactance multiturn magnetic loops so that it is suitable for measuring current position as well as amplitude. Four identical stripline coils are wound one per quadrant around a non magnetic core. The sensitivity is similar to that of a lumped coil system, with the added advantage of increased bandwidth. The voltages induced on the four separate coils are compared and suitable signal conditioning is performed to recover beam position and intensity information.

  13. Beam position and total current monitor for heavy ion fusion beams

    SciTech Connect

    Berners, D.; Reginato, L.L.

    1992-10-01

    Heavy Ion Fusion requires moderate currents, 1-10A, for a duration of about 1 [mu]s. For accurate beam transport, the center of charge must be located to within [plus minus] 100 [mu]m. Beam position and intensity may be excited at frequencies approaching 10 MHz, and the monitoring system must have adequate bandwidth to respond at these frequencies. We have modified the Rogowski technique by using distributed reactance multiturn magnetic loops so that it is suitable for measuring current position as well as amplitude. Four identical stripline coils are wound one per quadrant around a non magnetic core. The sensitivity is similar to that of a lumped coil system, with the added advantage of increased bandwidth. The voltages induced on the four separate coils are compared and suitable signal conditioning is performed to recover beam position and intensity information.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Astrophysics Data System (ADS)

    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

  16. Hybrid monitor for both beam position and tilt of pulsed high-current beams

    SciTech Connect

    Pang, J. He, X.; Ma, C.; Zhao, L.; Li, Q.; Dai, Z.

    2014-09-15

    A Hybrid beam monitor, integrated with both azimuthal and axial B-dot probes, was designed for simultaneous measurement of both beam position and beam angle for pulsed high-current beams at the same location in beam pipe. The output signals of axial B-dot probes were found to be mixed with signals caused by transverse position deviation. In order to eliminate the unwanted signals, an elimination method was developed and its feasibility tested on a 50-Ω coaxial line test stand. By this method, a waveform, shape-like to that of input current and proportional to the tilt angle, was simulated and processed by following integration step to achieve the tilt angle. The tests showed that the measurement error of displacement and tilt angle less than 0.3 mm and 1.5 mrad, respectively. The latter error could be reduced with improved probes by reducing the inductance of the axial B-dot probe, but the improvement reached a limit due to some unknown systemic mechanism.

  17. Simple photoelectron x-ray beam position monitor for synchrotron radiation

    SciTech Connect

    Heald, S.M.

    1985-01-01

    A UHV compatible x-ray beam position monitor is described. The monitor operates by detecting the photoelectrons emitted by two parallel tungsten wires. A key feature of the monitor is the simplicity of its design and construction which allows it to fit on a 2 3/4 in. conflat flange. When combined with a simple log-ratio current amplifier the monitor gives an output linear in the beam position with a sensitivity better than 0.02 mm.

  18. Ion beam induced surface graphitization of CVD diamond for x-ray beam position monitor applications

    SciTech Connect

    Liu, Chian; Shu, D.; Kuzay, T.M.; Wen, L.; Melendres, C.A. |

    1996-12-31

    The Advanced Photon Source at ANL is a third-generation synchrotron facility that generates powerful x-ray beams on its undulator beamlines. It is important to know the position and angle of the x- ray beam during experiments. Due to very high heat flux levels, several patented x-ray beam position monitors (XBPM) exploiting chemical vapor deposition (CVD) diamond have been developed. These XBPMs have a thin layer of low-atomic-mass metallic coating so that photoemission from the x rays generate a minute but measurable current for position determination. Graphitization of the CVD diamond surface creates a very thin, intrinsic and conducting layer that can stand much higher temperatures and minimal x-ray transmission losses compared to the coated metallic layers. In this paper, a laboratory sputter ion source was used to transform selected surfaces of a CVD diamond substrate into graphite. The effect of 1-5 keV argon ion bombardment on CVD diamond surfaces at various target temperatures from 200 to 500 C was studied using Auger electron spectroscopy and in-situ electrical resistivity measurements. Graphitization after the ion bombardment has been confirmed and optimum conditions for graphitization studied. Raman spectroscopy was used to identify the overall diamond structure in the bulk of CVD diamond substrate after the ion bombardments. It was found that target temperature plays an important role in stability and electrical conductivity of the irradiated CVD diamonds.

  19. Compact integrated X-ray intensity and beam position monitor based on rare gas scintillation

    SciTech Connect

    Revesz, Peter; Ruff, Jacob; Dale, Darren; Krawczyk, Thomas

    2013-05-15

    We have created and tested a compact integrated X-ray beam intensity and position monitor using Ar-gas scintillation. The light generated inside the device's cavity is detected by diametrically opposed PIN diodes located above and below the beam. The intensity is derived from the sum of the top and bottom signals, while the beam position is calculated from the difference-over-sum of the two signals. The device was tested at Cornell High Energy Synchrotron Source with both 17 keV and 59 keV x-rays. For intensity monitoring, the Ar-scintillation monitor performance is comparable to standard ion chambers in terms of precision. As an X-ray beam position monitor the new device response is linear with vertical beam position over a 2 mm span with a precision of 2 {mu}m.

  20. Evaluation and Correction of the Non-linear Distortion of CEBAF Beam Position Monitors

    SciTech Connect

    M. Spata, T.L. Allison, K.E. Cole, J. Musson, J. Yan

    2011-09-01

    The beam position monitors at CEBAF have four antenna style pickups that are used to measure the location of the beam. There is a strong nonlinear response when the beam is far from the electrical center of the device. In order to conduct beam experiments at large orbit excitation we need to correct for this nonlinearity. The correction algorithm is presented and compared to measurements from our stretched wire BPM test stand.

  1. A new measurement method for electrode gain in an orthogonally symmetric beam position monitor

    NASA Astrophysics Data System (ADS)

    Zou, Jun-Ying; Wu, Fang-Fang; Yang, Yong-Liang; Sun, Bao-Gen; Zhou, Ze-Ran; Luo, Qing; Lu, Ping; Xu, Hong-Liang

    2014-12-01

    The new beam position monitor (BPM) system of the injector at the upgrade project of the Hefei Light Source (HLS II) has 19 stripline beam position monitors. Most consist of four orthogonally symmetric stripline electrodes. Differences in electronic gain and mismachining tolerance can cause changes in the beam response of the BPM electrodes. This variation will couple the two measured horizontal positions, resulting in measuring error. To alleviate this effect, a new technique to measure the relative response of the four electrodes has been developed. It is independent of the beam charge, and the related coefficient can be calculated theoretically. The effect of electrode 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%.

  2. Reconstruction of lattice parameters and beam momentum distribution from turn-by-turn beam position monitor readings in circular accelerators

    NASA Astrophysics Data System (ADS)

    Edmonds, C. S.; Gratus, J.; Hock, K. M.; Machida, S.; Muratori, B. D.; Torromé, R. G.; Wolski, A.

    2014-05-01

    In high chromaticity circular accelerators, rapid decoherence of the betatron motion of a particle beam can make the measurement of lattice and bunch values, such as Courant-Snyder parameters and betatron amplitude, difficult. A method for reconstructing the momentum distribution of a beam from beam position measurements is presented. Further analysis of the same beam position monitor data allows estimates to be made of the Courant-Snyder parameters and the amplitude of coherent betatron oscillation of the beam. The methods are tested through application to data taken on the linear nonscaling fixed field alternating gradient accelerator, EMMA.

  3. RF Beam Position Monitor for the SNS Ring

    SciTech Connect

    Vetter, Kurt; Cameron, Peter; Dawson, Craig; Degen, Chris; Kesselman, Martin; Mead, Joseph

    2004-11-10

    The Spallation Neutron Source Ring accumulates 1060 pulses of 38-mA peak current 1-GeV H-minus particles from the Linac through the HEBT line, then delivers this accumulated beam in a single pulse to a mercury target via the RTBT line. The dynamic range over the course of the accumulation cycle is 60 dB. As a result of particle energy distribution the 402.5-MHz RF bunching frequency quickly de-coheres during the first few turns. In order to measure first-turn position a dual-mode BPM has been designed to process 402.5-MHz signal energy during the first few turns then switch to a Baseband mode to process de-cohered energy in the low MHz region. The design has been implemented as a dual mother/daughter board PCI architecture. Both Baseband and RF calibration are included on the RF BPM board. A prototype system has been installed in the SNS Linac.

  4. Simple beam profile monitor

    SciTech Connect

    Gelbart, W.; Johnson, R. R.; Abeysekera, B.

    2012-12-19

    An inexpensive beam profile monitor is based on the well proven rotating wire method. The monitor can display beam position and shape in real time for particle beams of most energies and beam currents up to 200{mu}A. Beam shape, position cross-section and other parameters are displayed on a computer screen.

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

    NASA Astrophysics Data System (ADS)

    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.

  6. Design of a subnanometer resolution beam position monitor for dielectric laser accelerators.

    PubMed

    Soong, Ken; Byer, Robert L

    2012-03-01

    We present a new concept for a beam position monitor with the unique ability to map particle beam position to a measurable wavelength. Coupled with an optical spectrograph, this beam position monitor is capable of subnanometer resolution. We describe one possible design, and through finite-element frequency-domain simulations, we show a resolution of 0.7 nm. Because of its high precision and ultracompact form factor, this device is ideal for future x-ray sources and laser-driven particle accelerators "on a chip."

  7. Residual Gas X-ray Beam Position Monitor Development for PETRA III

    SciTech Connect

    Ilinski, P.; Hahn, U.; Schulte-Schrepping, H.; Degenhardt, M.

    2007-01-19

    The development effort is driven by the need for a new type of x-ray beam position monitor (XBPM), which will detect the centre of gravity of the undulator beam. XBPMs based on the ionization of a residual gas are considered being the candidate for this future ''white'' undulator beam XBPMs. A number of residual gas XBPM prototypes for the PETRA III storage ring were developed and tested. Tests were performed at DESY and the ESRF, resolution of beam position up to 5 {mu}m is reported. The further development of the RGXBPMs will be focused on improvements of resolution, readout speed and reliability.

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

    NASA Astrophysics Data System (ADS)

    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 < 5 μm. The combination of two independent 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.

  9. On the calibration of TEVATRON beam position and intensity monitors used in E778

    SciTech Connect

    Merminga, L.; Gerig, R.; Peggs, S.

    1988-05-01

    In the second run of E778 two sets of electronics were used to record the motion of the center of mass of the beam. The first, the standard Fermilab Beam Position Monitor (BPM) front end, gives direct horizontal, vertical and intensity signals. The second is a peak sensing circuit which gives signals from the separate plates of two horizontal and one vertical pickup. This note addresses the question of calibration of the signals from the standard Tevatron beam position (HF42 and HF44 in the case of E778) and intensity monitors (I-45). Following is the summary of this study: Calibration Constants /minus/ Position Monitors = .0083 mm/mV; Smear data = /minus/147 LSB/10/sup 10/ particles; Resonance island data = (/minus/134 +- 7) LSB/10/sup 10/ particles. 6 figs.

  10. Support means for a particle beam position monitor

    DOEpatents

    VanZwienen, William H.

    1991-01-01

    A support means for a plurality of thermally deformable component parts that are concentrically mounted within a thermally expandable housing. The support means includes a plurality of pins that are mounted in relatively fixed or sliding relationship to either one of the concentrically positioned components or to the housing, and the pins are positioned to extend through aligned apertures in the remaining components or the housing in a manner such that the pins are free to slide in a snug relationship relative to the sides of the holes through those components or the housing. The support means enables the concentrically mounted components and the housing to undergo expansion and contraction movement, radially and longitudinally relative to one another, while maintaining concentricity of the components and the housing relative to one another.

  11. Development of a hard x-ray beam position monitor for insertion device beams at the APS.

    SciTech Connect

    Decker, G.; Rosenbaum, G.; Singh, O.; Accelerator Systems Division

    2006-01-01

    Long-term pointing stability requirements at the Advanced Photon Source (APS) are very stringent, at the level of 500 nanoradians peak-to-peak or better over a one-week time frame. Conventional rf beam position monitors (BPMs) close to the insertion device source points are incapable of assuring this level of stability, owing to mechanical, thermal, and electronic stability limitations. Insertion device gap-dependent systematic errors associated with the present ultraviolet photon beam position monitors similarly limit their ability to control long-term pointing stability. We report on the development of a new BPM design sensitive only to hard x-rays. Early experimental results will be presented.

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

    NASA Astrophysics Data System (ADS)

    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.

  13. Construction and measurement techniques for the APS LEUTL project RF beam position monitors.

    SciTech Connect

    Gorski, A.

    1999-04-20

    The design, construction, and assembly procedure of 24 rf beam position monitors used in the Advanced Photon Source low-energy undulator test line and linear accelerator (linac) are described. Beam stability as well as beam positioning capabilities are essential to the LEUTL project. A design objective of the LEUTL facility is to achieve better than 1-{micro}m resolution. The highest care was used in the mechanical fabrication and assembly of the BPM units. The latest experimental results using these BPMs are presented.

  14. Beam position monitoring in the AGS Linac to Booster transfer line

    SciTech Connect

    Shea, T.J.; Brodowski, J.; Witkover, R.

    1991-12-31

    A beam position monitor system has been developed and used in the commissioning of Brookhaven`s Linac to Booster transfer line. This line transports a chopped, RF modulated H- beam from the 200 MeV Linac to the AGS Booster. Over a 15dB dynamic range in beam current, the position monitor system provides a real-time, normalized position signal with an analog bandwidth of about 20 MHz. Seven directional coupler style pickups are installed in the line with each pickup sensing both horizontal and vertical position. Analog processing electronics are located in the tunnel and incorporate the amplitude modulation to phase modulation normalization technique. To avoid interference from the 200 MHz linac RF system, processing is performed at 400 MHz. This paper will provide a system overview and report results from the commissioning experience.

  15. Beam position monitoring in the AGS Linac to Booster transfer line

    SciTech Connect

    Shea, T.J.; Brodowski, J.; Witkover, R.

    1991-01-01

    A beam position monitor system has been developed and used in the commissioning of Brookhaven's Linac to Booster transfer line. This line transports a chopped, RF modulated H- beam from the 200 MeV Linac to the AGS Booster. Over a 15dB dynamic range in beam current, the position monitor system provides a real-time, normalized position signal with an analog bandwidth of about 20 MHz. Seven directional coupler style pickups are installed in the line with each pickup sensing both horizontal and vertical position. Analog processing electronics are located in the tunnel and incorporate the amplitude modulation to phase modulation normalization technique. To avoid interference from the 200 MHz linac RF system, processing is performed at 400 MHz. This paper will provide a system overview and report results from the commissioning experience.

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

    NASA Astrophysics Data System (ADS)

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

    2016-09-01

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

  17. Development of Electronics for the ATF2 Interaction Point Region Beam Position Monitor

    SciTech Connect

    Kim, Youngim; Heo, Ae-young; Kim, Eun-San; Boogert, Stewart; Honda, Yosuke; Tauchi, Toshiaki; Terunuma, Nobuhiro; May, Justin; McCormick, Douglas; Smith, Tonee; /SLAC

    2012-08-14

    Nanometer resolution beam position monitors have been developed to measure and control beam position stability at the interaction point region of ATF2. The position of the beam has to be measured to within a few nanometers at the interaction point. In order to achieve this performance, electronics for the low-Q IP-BPM was developed. Every component of the electronics have been simulated and checked on the bench and using the ATF2 beam. We will explain each component and define their working range. Then, we will show the performance of the electronics measured with beam signal. ATF2 is a final focus test beam line for ILC in the framework of the ATF international collaboration. The new beam line was constructed to extend the extraction line at ATF, KEK, Japan. The first goal of ATF2 is the acheiving of a 37 nm vertical beam size at focal point (IP). The second goal is to stabilize the beam at the focal point at a few nanometer level for a long period in order to ensure the high luminosity. To achieve these goals a high resolution IP-BPM is essential. In addition for feedback applications a low-Q system is desirable.

  18. Design and performance of a high resolution, low latency stripline beam position monitor system

    NASA Astrophysics Data System (ADS)

    Apsimon, R. J.; Bett, D. R.; Blaskovic Kraljevic, N.; Burrows, P. N.; Christian, G. B.; Clarke, C. I.; Constance, B. D.; Dabiri Khah, H.; Davis, M. R.; Perry, C.; Resta López, J.; Swinson, C. J.

    2015-03-01

    A high-resolution, low-latency beam position monitor (BPM) system has been developed for use in particle accelerators and beam lines that operate with trains of particle bunches with bunch separations as low as several tens of nanoseconds, such as future linear electron-positron colliders and free-electron lasers. The system was tested with electron beams in the extraction line of the Accelerator Test Facility at the High Energy Accelerator Research Organization (KEK) in Japan. It consists of three stripline BPMs instrumented with analogue signal-processing electronics and a custom digitizer for logging the data. The design of the analogue processor units is presented in detail, along with measurements of the system performance. The processor latency is 15.6 ±0.1 ns . A single-pass beam position resolution of 291 ±10 nm has been achieved, using a beam with a bunch charge of approximately 1 nC.

  19. Successive approximation algorithm for beam-position-monitor-based LHC collimator alignment

    NASA Astrophysics Data System (ADS)

    Valentino, Gianluca; Nosych, Andriy A.; Bruce, Roderik; Gasior, Marek; Mirarchi, Daniele; Redaelli, Stefano; Salvachua, Belen; Wollmann, Daniel

    2014-02-01

    Collimators with embedded beam position monitor (BPM) button electrodes will be installed in the Large Hadron Collider (LHC) during the current long shutdown period. For the subsequent operation, BPMs will allow the collimator jaws to be kept centered around the beam orbit. In this manner, a better beam cleaning efficiency and machine protection can be provided at unprecedented higher beam energies and intensities. A collimator alignment algorithm is proposed to center the jaws automatically around the beam. The algorithm is based on successive approximation and takes into account a correction of the nonlinear BPM sensitivity to beam displacement and an asymmetry of the electronic channels processing the BPM electrode signals. A software implementation was tested with a prototype collimator in the Super Proton Synchrotron. This paper presents results of the tests along with some considerations for eventual operation in the LHC.

  20. Design of a Standing-Wave Multi-Cavity Beam-Monitor for Simultaneous Beam Position and Emittance Measurements

    NASA Astrophysics Data System (ADS)

    Kim, Jin-Soo; Miller, Roger; Nantista, Christopher

    2004-12-01

    A high precision emittance measurement requires precise beam position at the measurement location. At present there is no existing technique, commercial or otherwise, for non-destructive pulse-to-pulse simultaneous beam position and emittance measurement. FAR-TECH, Inc. is currently developing a high precision cavity-based beam monitor for simultaneous beam position and emittance measurements pulse-to-pulse, without beam interception and without moving parts. The design and anlysis of a multi-cavity standing wave structure for a pulse-to-pulse emittance measurement system in which the quadrupole and the dipole standing wave modes resonate at harmonics of the beam operating frequency is presented. Considering the Next Linear Collider beams, an optimized 9-cavity standing wave system is designed for simultaneous high precision beam position and emittance measurements. It operates with the π - quadrupole mode resonating at 16th harmonic of the NLC bunch frequency, and the 3 π /4 dipole mode at 12th harmonic (8.568 GHz). The 9-cavity system design indicates that the two dipoles resonate almost at the same frequency 8.583 GHz and the quadrupole at 11.427 GHz according to the scattering parameter calculations. The design can be trivially scaled so that the dipole frequency is at 8.568 GHz, and the quadrupole frequency can then be tuned during fabrication to achieve the desired 11.424 GHz. The output powers from these modes are estimated for the NLC beams. An estimated rms-beam size resolution is sub micro-meters and beam positions in sub nano-meters.

  1. Beam position and energy monitoring in compact linear accelerators for radiotherapy.

    PubMed

    Ruf, Marcel; Müller, Sven; Setzer, Stefan; Schmidt, Lorenz-Peter

    2014-02-01

    The experimental verification of a novel sensor topology capable of measuring both the position and energy of an electron beam inside a compact electron linear accelerator for radiotherapy is presented. The method applies microwave sensing techniques and allows for the noninterceptive monitoring of the respective beam parameters within compact accelerators for medical or industrial purposes. A state space feedback approach is described with the help of which beam displacements, once detected, can be corrected within a few system macropulses. The proof-of-principle experiments have been conducted with a prototype accelerator and customized hardware. Additionally, closed-loop operation with high accuracy is demonstrated.

  2. Progress of the APS high heat load X-ray beam position monitor development

    SciTech Connect

    Shu, D.; Barraza, J.; Ding, H.; Kuzay, T.M.; Ramanathan, M.

    1997-09-01

    Several novel design developments have been established for the Advanced Photon Source (APS) insertion device (ID) X-ray beam position monitor (XBPM) to improve its performance: (1) optimized geometric configuration of the monitor`s sensory blades; (2) smart XBPM system with an intelligent digital signal processor, which provides a self-learning and calibration function; and (3) transmitting XBPM with prefiltering in the commissioning windows for the front end. In this write-up, the authors summarize the recent progress on the XBPM development for the APS ID front ends.

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

    SciTech Connect

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

    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.

  4. Uncovering beam position monitor noise at the Relativistic Heavy Ion Collider

    NASA Astrophysics Data System (ADS)

    Shen, X.; Lee, S. Y.; Bai, M.

    2015-01-01

    We apply the independent component analysis (ICA) algorithm to uncover intrinsic noise in the beam position monitor (BPM) system. Numerical simulations found that ICA is efficient in the BPM noise estimation. The ICA algorithm is applied to the turn-by-turn data at the Relativistic Heavy Ion Collider. We found the distribution of the BPM noise level, which is consistent with the Johnson-Nyquist thermal noise model. The ICA analysis of turn-by-turn data can be used in neuronetwork feasibility of monitoring a storage ring parasitically.

  5. New configuration of photoconductive-type diamond detector head for X-ray beam position monitors

    NASA Astrophysics Data System (ADS)

    Aoyagi, Hideki; Kudo, Togo; Tanida, Hajime; Kitamura, Hideo

    2004-05-01

    We designed and fabricated new diamond detector head for an X-ray beam position monitor (XBPM). This monitor operates in photoconductive mode, and is shaped into a blade in order to reduce heat load. A pair of aluminum electrodes is formed on both sides of the diamond blade. The profile of the detection efficiency inside the diamond detector head was measured. The signal current is generated only between the pair of electrodes. The bias voltage dependence of signal current along a section of the detector head is also measured. The results show that the detector head operates in photoconductive mode. We demonstrated that this detector head is feasible for the XBPM.

  6. Hiresmon: A Fast High Resolution Beam Position Monitor for Medium Hard and Hard X-Rays

    SciTech Connect

    Menk, Ralf Hendrik; Giuressi, Dario; Arfelli, Fulvia; Rigon, Luigi

    2007-01-19

    The high-resolution x-ray beam position monitor (XBPM) is based on the principle of a segmented longitudinal ionization chamber with integrated readout and USB2 link. In contrast to traditional transversal ionization chambers here the incident x-rays are parallel to the collecting field which allows absolute intensity measurements with a precision better than 0.3 %. Simultaneously the beam position in vertical and horizontal direction can be measured with a frame rate of one kHz. The precision of position encoding depends only on the SNR of the synchrotron radiation and is in the order of micro meters at one kHz frame rate and 108 photon /sec at 9 KeV.

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

    SciTech Connect

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    SciTech Connect

    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.

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

    NASA Astrophysics Data System (ADS)

    Muguira, L.; Belver, D.; Etxebarria, V.; Varnasseri, S.; Arredondo, I.; del Campo, M.; Echevarria, P.; Garmendia, N.; Feuchtwanger, J.; Jugo, J.; Portilla, J.

    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.

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

    SciTech Connect

    Petrenko, A.V.; 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.

  13. Utilizing the N beam position monitor method for turn-by-turn optics measurements

    NASA Astrophysics Data System (ADS)

    Langner, A.; Benedetti, G.; Carlà, M.; Iriso, U.; Martí, Z.; de Portugal, J. Coello; Tomás, R.

    2016-09-01

    The N beam position monitor method (N -BPM) which was recently developed for the LHC has significantly improved the precision of optics measurements that are based on BPM turn-by-turn data. The main improvement is due to the consideration of correlations for statistical and systematic error sources, as well as increasing the amount of BPM combinations which are used to derive the β -function at one location. We present how this technique can be applied at light sources like ALBA, and compare the results with other methods.

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

    NASA Astrophysics Data System (ADS)

    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.

  15. New beam-position monitor system for upgraded Photon Factory storage ring.

    PubMed

    Haga, K; Honda, T; Tadano, M; Obina, T; Kasuga, T

    1998-05-01

    Accompanying the brilliance-upgrading project at the Photon Factory storage ring, the beam-position monitor (BPM) system has been renovated. The new system was designed to enable precise and fast measurements to correct the closed-orbit distortion (COD), as well as to feed back the orbit position during user runs. There are 42 BPMs newly installed, amounting to a total of 65 BPMs. All of the BPMs are calibrated on the test bench using a coaxially strung metallic wire. The measured electrical offsets are typically 200 micro m in both directions, which is 1/2-1/3 of those of the old-type BPMs. In the signal-processing system, PIN diode switches are employed in order to improve reliability. In the fastest mode, this system is capable of measuring COD within about 10 ms; this fast acquisition will allow fast suppression of the beam movement for frequencies up to 50 Hz using a global feedback system. PMID:15263599

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

    NASA Astrophysics Data System (ADS)

    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.

  17. A proposed interim improvement to the Tevatron beam position monitors with narrow band crystal filters

    SciTech Connect

    Cheng-Yang Tan

    2003-08-25

    Since the start of Run II, we have found that we are unable to reliably and accurately measure the beam position with the present BPM system during high energy physics (HEP). This problem can be traced back to the analogue frontend called the AM/PM module which has trouble handling coalesced beam, but works well with uncoalesced beam. In this paper, we propose a simple fix to the AM/PM module so that we can measure the beam position during HEP. The idea is to use narrow band crystal filters which ring when pinged by coalesced beam so that the AM/PM module is tricked into thinking that it is measuring uncoalesced beam.

  18. Electromagnetic design of the RF cavity beam position monitor for the LCLS.

    SciTech Connect

    Waldschmidt, G.; Lill, B.; Morrison, L.

    2008-01-01

    A high-resolution X-band cavity BPM has been developed for the LCLS. A dipole mode cavity and a monopole mode reference cavity have been designed in order to achieve micron-level accuracy of the beam position. The rf properties of the BPM as well as beam interaction with the cavities will be discussed including output power and tuning. In addition, methods will be presented for improving the isolation of the output ports to differentiate between horizontal/vertical beam motion and to reject extraneous modes from affecting the output signal. The predicted simulation results will be compared to data collected from low-power experimental tests.

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

    NASA Astrophysics Data System (ADS)

    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.

  20. Triangle and concave pentagon electrodes for an improved broadband frequency response of stripline beam position monitors

    NASA Astrophysics Data System (ADS)

    Shobuda, Yoshihiro; Chin, Yong Ho; Takata, Koji; Toyama, Takeshi; Nakamura, Keigo

    2016-02-01

    The frequency domain performance of a stripline beam position monitor depends largely on the longitudinal shape of its electrode. Some shapes other than a conventional rectangle have been proposed and tested. To attain a good impedance matching along the electrode, they need to be precisely bent down toward their downstream in proportion to their width. This is a considerable task, and a failure to comply with it will result in a large distortion of the frequency-domain transfer function from the ideal one due to unwanted signal reflections. In this report, we first propose a triangle electrode for easy fabrication and setup: it only requires that a triangularly cut flat electrode will be placed in a chamber while being obliquely inclined toward the downstream port. Theoretical and simulation results show that the simple triangle electrode has a remarkably flatter frequency response than the rectangle one. The frequency response, in particular at high frequencies, can be further improved by attaching an "apron" plate, perpendicular to the upstream edge of the electrode. The overshooting of the frequency response at low frequency can be eliminated by replacing the straight sidelines of the triangle by three-point polylines (with a result that the triangle is transformed to a concave pentagon). The concave pentagon electrode needs to be bent only once at the middle point of the polylines for a good impedance matching and thus its fabrication and setup remain to be easy. Rf measurements for the various electrode shapes have been carried out. We found that the concave pentagon electrode achieves a wide and flat frequency response up to about 4 GHz for the J-PARC Main Ring (MR).

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

    NASA Astrophysics Data System (ADS)

    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.

  2. Conceptual design of a high precision dual directional beam position monitoring system for beam crosstalk cancellation and improved output pulse shapes

    SciTech Connect

    Thieberger P.; Dawson, C.; Fischer, W.; Gassner, D.; Hulsart, R.; Mernick, K.; Michnoff, R.; Minty, M.

    2012-04-15

    The Relativistic Heavy Ions Collider (RHIC) would benefit from improved beam position measurements near the interaction points that see both beams, especially as the tolerances become tighter when reducing the beam sizes to obtain increased luminosity. Two limitations of the present beam position monitors (BPMs) would be mitigated if the proposed approach is successful. The small but unavoidable cross-talk between signals from bunches traveling in opposite directions when using conventional BPMs will be reduced by adopting directional BPMs. Further improvements will be achieved by cancelling residual cross-talk using pairs of such BPMs. Appropriately delayed addition and integration of the signals will also provide pulses with relatively flat maxima that will be easier to digitize by relaxing the presently very stringent timing requirements.

  3. Laser beam monitoring system

    DOEpatents

    Weil, Bradley S.; Wetherington, Jr., Grady R.

    1985-01-01

    Laser beam monitoring systems include laser-transparent plates set at an angle to the laser beam passing therethrough and light sensor for detecting light reflected from an object on which the laser beam impinges.

  4. ELECTRO-OPTIC BEAM POSITION AND PULSED POWER MONITORS FOR THE SECOND AXIS OF DARHT.

    SciTech Connect

    M. BRUBAKER; C. EKDAHL; C. YAKYMYSHYN

    2001-05-01

    The second axis of the Dual Axis Radiographic Hydro-Test (DARHT) facility utilizes a long pulse electron beam having a duration in excess of two microseconds. This time scale poses problems for many conventional diagnostics that rely upon electrical cables to transmit signals between the accelerator and recording equipment. Recognizing that transit time isolation is not readily achieved for the long pulse regime, difficulties resulting from ground loops are anticipated. An electro-optic (EO) voltage sensor technology has been developed to address this issue. The EO sensor exploits the Pockels effect in Bi{sub 4}Ge{sub 3}O{sub 12} (BGO) to provide linear modulation of laser light in response to the voltage induced on a pickup electrode. Fiber coupling between the light source, Pockels cell and receiver ensures complete galvanic isolation with improved cost and performance as compared to conventional sensors fitted with fiber optic links. Furthermore, the EO approach requires that only the passive sensor element be located near the accelerator while the light source and receiver can be installed in remote locations. This paper describes the design and development of EO sensors for electron beam and pulsed power monitoring on the second axis of DARHT. Typical calibration and testing data for the sensors is also presented.

  5. Neutral beam monitoring

    DOEpatents

    Fink, Joel H.

    1981-08-18

    Method and apparatus for monitoring characteristics of a high energy neutral beam. A neutral beam is generated by passing accelerated ions through a walled cell containing a low energy neutral gas, such that charge exchange neutralizes the high energy ion beam. The neutral beam is monitored by detecting the current flowing through the cell wall produced by low energy ions which drift to the wall after the charge exchange. By segmenting the wall into radial and longitudinal segments various beam conditions are further identified.

  6. Development of a High-speed X-ray Beam Position Monitor using a Detector Head with Low Electrical Capacitance

    NASA Astrophysics Data System (ADS)

    Kudo, T. P.; Aoyagi, H.; Awaji, M.; Kobayashi, T.; Kitamura, H.

    2004-05-01

    A high speed x-ray beam monitor using tungsten blades with low electrical capacitance (<14pF) was prepared and examined its responses to the short pulsed x-ray at a SPring-8 standard undulator beam line (BL47XU). The rise and decay time of about 1ns were obtained. The monitor provided clearer bunch structures than those with a conventional blade. Rise time of the signal was independent on a voltage applied to the photoelectron collector.

  7. Beam Position Monitoring with Cavity Higher Order Modes in the Superconducting Linac FLASH

    SciTech Connect

    Baboi, N.; Molloy, S.; Eddy, N.; Frisch, J.; Hendrickson, L.; Hensler, O.; McCormick, D.; May, J.; Nagaitsev, S.; Napoly, O.; Paparella, R.C.; Petrosian, L.; Piccolli, L.; Rechenmacher, R.; Ross, M.; Simon, C.; Smith, T.; Watanabe, K.; Wendt, M.; /DESY /SLAC /Fermilab /DAPNIA, Saclay /KEK, Tsukuba

    2007-03-20

    FLASH (Free Electron Laser in Hamburg) is a user facility for a high intensity VUV-light source [1]. The radiation wavelength is tunable in the range from about 40 to 13 nm by changing the electron beam energy from 450 to 700 MeV. The accelerator is also a test facility for the European XFEL (X-ray Free Electron Laser) to be built in Hamburg [2] and the project study ILC (International Linear Collider) [3]. The superconducting TESLA technology is tested at this facility, together with other accelerator components.

  8. Picosecond beam monitor

    DOEpatents

    Schutt, D.W.; Beck, G.O.

    1974-01-01

    The current in the beam of a particle accelerator is monitored with picosecond resolution by causing the beam to impinge upon the center conductor of a coaxial line, generating a pulse of electromagnetic energy in response thereto. This pulse is detected by means such as a sampling oscilloscope. (Official Gazette)

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

    NASA Astrophysics Data System (ADS)

    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.

  10. In Process Beam Monitoring

    NASA Astrophysics Data System (ADS)

    Steen, W. M.; Weerasinghe, V. M.

    1986-11-01

    The industrial future of lasers in material processing lies in the combination of the laser with automatic machinery. One possible form of such a combination is an intelligent workstation which monitors the process as it occurs and adjusts itself accordingly, either by self teaching or by comparison to a process data bank or algorithm. In order to achieve this attractive goal in-process signals are required. Two devices are described in this paper. One is the Laser Beam Analyser which is now maturing into a second generation with computerised output. The other is the Acoustic Mirror, a totally novel analytic technique, not yet fully understood, but which nevertheless can act as a very effective process monitor.

  11. Photodiode-Based X-Ray Beam-Position Monitor With High Spatial-Resolution for the NSLS-II Beamlines

    SciTech Connect

    Yoon, P.S.; Siddons, D. P.

    2009-05-25

    We developed a photodiode-based monochromatic X-ray beam-position monitor (X-BPM) with high spatial resolution for the project beamlines of the NSLS-II. A ring array of 32 Si PIN-junction photodiodes were designed for use as a position sensor, and a low-noise HERMES4 ASIC chip was integrated into the electronic readout system. A series of precision measurements to characterize electrically the Si-photodiode sensor and the ASIC chip demonstrated that the inherent noise is sufficiently below tolerance levels. Following up modeling of detector's performance, including geometrical optimization using a Gaussian beam, we fabricated and assembled a first prototype. In this paper, we describe the development of this new state-of-the-art X-ray BPM along the beamline, in particular, downstream from the monochromator.

  12. Position-And-Direction Sensor For Light Beams

    NASA Technical Reports Server (NTRS)

    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.

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

    PubMed

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

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

    NASA Astrophysics Data System (ADS)

    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.

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

    SciTech Connect

    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

    2015-01-15

    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.

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

    PubMed

    Noh, Seon Yeong; Kim, Eun-San; Hwang, Ji-Gwang; Heo, A; Jang, Si won; Vinokurov, Nikolay A; Jeong, Young U K; Park, Seong Hee; 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. PMID:25638104

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

    NASA Astrophysics Data System (ADS)

    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.

  18. Smart x-ray beam position monitor system using artificial intelligence methods for the Advanced Photon Source insertion-device beamlines

    SciTech Connect

    Shu, D.; Ding, H.; Barraza, J.; Kuzay, T.M.; Haeffner, D.; Ramanathan, M.

    1997-09-01

    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. PERISCOPE POP-IN BEAM MONITOR.

    SciTech Connect

    JOHNSON,E.D.

    1998-05-07

    We have built monitors for use as beam diagnostics in the narrow gap of an undulator for an FEL experiment. They utilize an intercepting screen of doped YAG scintillating crystal to make light that is imaged through a periscope by conventional video equipment. The absolute position can be ascertained by comparing the electron beam position with the position of a He:Ne laser that is observed by this pop-in monitor. The optical properties of the periscope and the mechanical arrangement of the system mean that beam can be spatially determined to the resolution of the camera, in this case approximately 10 micrometers. Our experience with these monitors suggests improvements for successor designs, which we also describe.

  20. Periscope pop-in beam monitor

    SciTech Connect

    Johnson, E.D.; Graves, W.S.; Robinson, K.E.

    1998-06-01

    The authors have built monitors for use as beam diagnostics in the narrow gap of an undulator for an FEL experiment. They utilize an intercepting screen of doped YAG scintillating crystal to make light that is imaged through a periscope by conventional video equipment. The absolute position can be ascertained by comparing the electron beam position with the position of a He:Ne laser that is observed by this pop-in monitor. The optical properties of the periscope and the mechanical arrangement of the system mean that beam can be spatially determined to the resolution of the camera, in this case approximately 10 micrometers. The experience with these monitors suggests improvements for successor designs, which they also describe.

  1. 21 CFR 892.5780 - Light beam patient position indicator.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Light beam patient position indicator. 892.5780 Section 892.5780 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... patient and to monitor alignment of the radiation beam with the patient's anatomy. (b)...

  2. 21 CFR 892.5780 - Light beam patient position indicator.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Light beam patient position indicator. 892.5780 Section 892.5780 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... patient and to monitor alignment of the radiation beam with the patient's anatomy. (b)...

  3. 21 CFR 892.5780 - Light beam patient position indicator.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Light beam patient position indicator. 892.5780 Section 892.5780 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... patient and to monitor alignment of the radiation beam with the patient's anatomy. (b)...

  4. 21 CFR 892.5780 - Light beam patient position indicator.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Light beam patient position indicator. 892.5780 Section 892.5780 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... patient and to monitor alignment of the radiation beam with the patient's anatomy. (b)...

  5. A Prototype Wire Position Monitoring System

    SciTech Connect

    Wang, Wei

    2010-12-07

    The Wire Position Monitoring System (WPM) will track changes in the transverse position of LCLS Beam Position Monitors (BPMs) to 1{micro}m over several weeks. This position information will be used between applications of beam based alignment to correct for changes in component alignment. The WPM system has several requirements. The sensor range must be large enough so that precision sensor positioning is not required. The resolution needs to be small enough so that the signal can be used to monitor motion to 1{micro}m. The system must be stable enough so that system drift does not mimic motion of the component being monitored. The WPM sensor assembly consists of two parts, the magnetic sensor and an integrated lock-in amplifier. The magnetic sensor picks up a signal from the alternating current in a stretched wire. The voltage v induced in the sensor is proportional to the wire displacement from the center of the sensor. The integrated lock-in amplifier provides a DC output whose magnitude is proportional to the AC signal from the magnetic sensor. The DC output is either read on a digital voltmeter or digitized locally and communicated over a computer interface.

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

    PubMed

    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

  7. Calibration of a proton beam energy monitor

    SciTech Connect

    Moyers, M. F.; Coutrakon, G. B.; Ghebremedhin, A.; Shahnazi, K.; Koss, P.; Sanders, E.

    2007-06-15

    Delivery of therapeutic proton beams requires an absolute energy accuracy of {+-}0.64 to 0.27 MeV for patch fields and a relative energy accuracy of {+-}0.10 to 0.25 MeV for tailoring the depth dose distribution using the energy stacking technique. Achromatic switchyard tunes, which lead to better stability of the beam incident onto the patient, unfortunately limit the ability of switchyard magnet tesla meters to verify the correct beam energy within the tolerances listed above. A new monitor to measure the proton energy before each pulse is transported through the switchyard has been installed into a proton synchrotron. The purpose of this monitor is to correct and/or inhibit beam delivery when the measured beam energy is outside of the tolerances for treatment. The monitor calculates the beam energy using data from two frequency and eight beam position monitors that measure the revolution frequency of the proton bunches and the effective offset of the orbit from the nominal radius of the synchrotron. The new energy monitor has been calibrated by measuring the range of the beam through water and comparing with published range-energy tables for various energies. A relationship between depth dose curves and range-energy tables was first determined using Monte Carlo simulations of particle transport and energy deposition. To reduce the uncertainties associated with typical scanning water phantoms, a new technique was devised in which the beam energy was scanned while fixed thickness water tanks were sandwiched between two fixed parallel plate ionization chambers. Using a multitude of tank sizes, several energies were tested to determine the nominal accelerator orbit radius. After calibration, the energy reported by the control system matched the energy derived by range measurements to better than 0.72 MeV for all nine energies tested between 40 and 255 MeV with an average difference of -0.33 MeV. A study of different combinations of revolution frequency and radial

  8. Beam-energy and laser beam-profile monitor at the BNL LINAC

    SciTech Connect

    Connolly, R.; Briscoe, B.; Degen, C.; DeSanto, L.; Meng, W.; Minty, M.; Nayak, S.; Raparia, D.; Russo, T.

    2010-05-02

    We are developing a non-interceptive beam profile and energy monitor for H{sup -} beams in the high energy beam transport (HEBT) line at the Brookhaven National Lab linac. Electrons that are removed from the beam ions either by laser photodetachment or stripping by background gas are deflected into a Faraday cup. The beam profile is measured by stepping a narrow laser beam across the ion beam and measuring the electron charge vs. transverse laser position. There is a grid in front of the collector that can be biased up to 125kV. The beam energy spectrum is determined by measuring the electron charge vs. grid voltage. Beam electrons have the same velocity as the beam and so have an energy of 1/1836 of the beam protons. A 200MeV H{sup -} beam yields 109keV electrons. Energy measurements can be made with either laser-stripped or gas-stripped electrons.

  9. Automatic Beam Position Control at LASREF

    NASA Astrophysics Data System (ADS)

    Oothoudt, M. A.; Pillai, C.; Zumbro, M. V.

    1997-05-01

    Historically the Los Alamos Spallation Radiation Effects Facility (LASREF) has used manual control to position the 800 kW, 800 MeV proton beam on targets. New experiments, however, require more stringent position control more frequently than can be done manually for long periods of time. Data from an existing harp was used to automatically adjust steering magnets to maintain beam position to required tolerances. Results and details of the system will be presented.

  10. Beam Profile Monitor With Accurate Horizontal And Vertical Beam Profiles

    DOEpatents

    Havener, Charles C [Knoxville, TN; Al-Rejoub, Riad [Oak Ridge, TN

    2005-12-26

    A widely used scanner device that rotates a single helically shaped wire probe in and out of a particle beam at different beamline positions to give a pair of mutually perpendicular beam profiles is modified by the addition of a second wire probe. As a result, a pair of mutually perpendicular beam profiles is obtained at a first beamline position, and a second pair of mutually perpendicular beam profiles is obtained at a second beamline position. The simple modification not only provides more accurate beam profiles, but also provides a measurement of the beam divergence and quality in a single compact device.

  11. Studies of beam heating of proton beam profile monitor SEM's

    SciTech Connect

    Pavlovich, Zarko; Osiecki, Thomas H.; Kopp, Sacha E.; /Texas U.

    2005-05-01

    The authors present calculations of the expected temperature rise of proton beam profile monitors due to beam heating. The profile monitors are secondary emission monitors (SEM's) to be made of Titanium foils. The heating is studied to understand whether there is any loss of tension or alignment of such devices. Additionally, calculations of thermally-induced dynamic stress are presented. Ti foil is compared to other materials and also to wire SEM's. The calculations were initially performed for the NuMI beam, where the per-pulse intensity is quite high; for completeness the calculations are also performed for other beam energies and intensities.

  12. Segmented ionization chambers for beam monitoring in hadrontherapy

    NASA Astrophysics Data System (ADS)

    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.

  13. Beam loss monitor system for the SSC

    SciTech Connect

    Johnson, R.G.; Mokhov, N.V.

    1993-10-01

    At full intensity the energy contained in each beam of the Superconducting Super Collider (SSC) is 400 MJ. The loss of a small fraction of that beam has the potential to cause magnet quenches or even severe damage to Collider components. To help protect the machine a sensitive and reliable beam loss monitor (BLM) system must be designed and built. In fact, BLM systems will be needed for all the accelerators of the SSC. The BLM system requirements for each of these accelerators will be discussed, but emphasis will be placed on the Collider. The discussion will include the preliminary design of BLM systems, the considerations that led to these designs, the calculations that were performed in development of the designs, and the problems that remain to be solved. A major tool in the design process has been a series of Monte Carlo calculations that were used to estimate beam loss distributions for the Collider arcs, the interaction regions, and the west utility region. These calculations were also used to study the fluence as a function of energy, the particle content, and the dose rate at selected positions. Detailed considerations such as detector spacing and sensitivity, loss fluctuations, reliability, and maintainability will be discussed. The proposed preliminary BLM system design for the Collider uses a radiation-hard, solid-state ionization detector and fast analog-to-digital conversion. Details of this design and relevant options will be discussed.

  14. In-line beam current monitor

    DOEpatents

    Ekdahl, C.A. Jr.; Frost, C.A.

    1984-11-13

    An intense relativistic electron beam current monitor for a gas neutralized beam transport line includes a first foil for conducting plasma current to the wall where it is measured as it traverses an inductive loop formed by a cavity in the wall. An insulator foil separates the first foil from a second conducting foil which returns the current to the plasma environment.

  15. In-line beam current monitor

    DOEpatents

    Ekdahl, Jr., Carl A.; Frost, Charles A.

    1986-01-01

    An intense relativistic electron beam current monitor for a gas neutralized beam transport line includes a first foil for conducting plasma current to the wall where it is measured as it traverses an inductive loop formed by a cavity in the wall. An insulator foil separates the first foil from a second conducting foil which returns the current to the plasma environment.

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

    PubMed

    Ko, J; Kim, I-Y; Kim, C; Kim, D-T; Huang, J-Y; Shin, S

    2016-03-01

    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. PMID:26917132

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

    PubMed

    Ko, J; Kim, I-Y; Kim, C; Kim, D-T; Huang, J-Y; Shin, S

    2016-03-01

    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.

  18. The ATLAS Beam Condition and Beam Loss Monitors

    NASA Astrophysics Data System (ADS)

    Dolenc, I.

    2010-04-01

    The primary goal of ATLAS Beam Condition Monitor (BCM) and Beam Loss Monitor (BLM) is to protect the ATLAS Inner Detector against damaging LHC beam incidents by initiating beam abort in case of beam failures. Poly-crystalline Chemical Vapour Deposition (pCVD) diamond was chosen as the sensor material for both systems. ATLAS BCM will provide real-time monitoring of instantaneous particle rates close to the interaction point (IP) of ATLAS spectrometer. Using fast front-end and signal processing electronics the time-of-flight and pulse amplitude measurements will be performed to distinguish between normal collisions and background events due to natural or accidental beam losses. Additionally, BCM will also provide coarse relative luminosity information. A second system, the ATLAS BLM, is an independent system which was recently added to complement the BCM. It is a current measuring system and was partially adopted from the BLM system developed by the LHC beam instrumentation group with pCVD diamond pad sensors replacing the ionisation chambers. The design of both systems and results of operation in ATLAS framework during the commissioning with cosmic rays will be reported in this contribution.

  19. A Beam Shape Oscillation Monitor for HERA

    SciTech Connect

    Afanasyev, O. V.; Baluev, A. B.; Gubrienko, K. I.; Merker, E. A.; Wittenburg, K.; Krouptchenkow, I.

    2006-11-20

    The perfect matching of the injecting beam phase space with the accelerator lattice is a very important problem. Its successful solution allows excluding possible mismatch emittance blow-up and worsening of the beam characteristics, that is necessary to get the highest possible luminosity in hadron accelerators. The mismatch can be controlled by measuring sizes oscillation on the first revolutions of the injected beam at a certain orbit point. Designed for this purpose the construction, acquisition electronics, software controlling of the operation and data processing of such a monitor are described. A first test result with beam is presented.

  20. Nondestructive synchronous beam current monitor

    SciTech Connect

    Covo, Michel Kireeff

    2014-12-15

    A fast current transformer is mounted after the deflectors of the Berkeley 88-Inch Cyclotron. The measured signal is amplified and connected to the input of a lock-in amplifier. The lock-in amplifier performs a synchronous detection of the signal at the cyclotron second harmonic frequency. The magnitude of the signal detected is calibrated against a Faraday cup and corresponds to the beam intensity. It has exceptional resolution, long term stability, and can measure the beam current leaving the cyclotron as low as 1 nA.

  1. A Phase Space Monitoring of Injected Beam of J-PARC MR

    NASA Astrophysics Data System (ADS)

    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.

  2. Beam Charge Asymmetry Monitors for Low Intensity Continuous Electron Beam

    SciTech Connect

    Jean-Claude Denard; Arne P. Freyberger; Youri Sharabian

    2001-05-01

    Experimental Hall B at Jefferson Lab typically operates with CW electron beam currents in the range of 1 - 10 nA. This low beam current coupled with a 30 Hz flip rate of the beam helicity required the development of new devices to measure and monitor the beam charge asymmetry. We have developed four independent devices with sufficient bandwidth for readout at 30 Hz rate: a synchrotron light monitor (SLM), two backward optical transition radiation monitors (OTR) and a Faraday Cup. Photomultipliers operating in current mode provided the readout of the light from the SLM and the OTRs, while high bandwidth electronics provided the readout from the Faraday cup. Using {approximately}6 helicity pairs, we measured the beam charge asymmetry to a statistically accuracy which is better than 0.05%. We present the results from the successful operation of these devices during the fall 2000 physics program. The reliability and the bandwidth of the devices allowed us to control the gain on the source laser by means of a feedback loop.

  3. Monitoring external beam radiotherapy using real-time beam visualization

    SciTech Connect

    Jenkins, Cesare H.; Naczynski, Dominik J.; Yu, Shu-Jung S.; Xing, Lei

    2015-01-15

    Purpose: To characterize the performance of a novel radiation therapy monitoring technique that utilizes a flexible scintillating film, common optical detectors, and image processing algorithms for real-time beam visualization (RT-BV). Methods: Scintillating films were formed by mixing Gd{sub 2}O{sub 2}S:Tb (GOS) with silicone and casting the mixture at room temperature. The films were placed in the path of therapeutic beams generated by medical linear accelerators (LINAC). The emitted light was subsequently captured using a CMOS digital camera. Image processing algorithms were used to extract the intensity, shape, and location of the radiation field at various beam energies, dose rates, and collimator locations. The measurement results were compared with known collimator settings to validate the performance of the imaging system. Results: The RT-BV system achieved a sufficient contrast-to-noise ratio to enable real-time monitoring of the LINAC beam at 20 fps with normal ambient lighting in the LINAC room. The RT-BV system successfully identified collimator movements with sub-millimeter resolution. Conclusions: The RT-BV system is capable of localizing radiation therapy beams with sub-millimeter precision and tracking beam movement at video-rate exposure.

  4. Monitoring external beam radiotherapy using real-time beam visualization

    PubMed Central

    Jenkins, Cesare H.; Naczynski, Dominik J.; Yu, Shu-Jung S.; Xing, Lei

    2015-01-01

    Purpose: To characterize the performance of a novel radiation therapy monitoring technique that utilizes a flexible scintillating film, common optical detectors, and image processing algorithms for real-time beam visualization (RT-BV). Methods: Scintillating films were formed by mixing Gd2O2S:Tb (GOS) with silicone and casting the mixture at room temperature. The films were placed in the path of therapeutic beams generated by medical linear accelerators (LINAC). The emitted light was subsequently captured using a CMOS digital camera. Image processing algorithms were used to extract the intensity, shape, and location of the radiation field at various beam energies, dose rates, and collimator locations. The measurement results were compared with known collimator settings to validate the performance of the imaging system. Results: The RT-BV system achieved a sufficient contrast-to-noise ratio to enable real-time monitoring of the LINAC beam at 20 fps with normal ambient lighting in the LINAC room. The RT-BV system successfully identified collimator movements with sub-millimeter resolution. Conclusions: The RT-BV system is capable of localizing radiation therapy beams with sub-millimeter precision and tracking beam movement at video-rate exposure. PMID:25563243

  5. Patient position verification in ion-beam therapy using ion-beam radiography and fiducial markers

    NASA Astrophysics Data System (ADS)

    Huber, Lucas; Telsemeyer, Julia; Martišíková, Mária; Jäkel, Oliver

    2011-11-01

    The basic rationale for radiation therapy using ion-beams is its high local precision of dose deposition. Therefore accurate patient positioning prior to and during beam application is a crucial part of the therapy. The current standard position verification procedure uses X-ray based imaging before each beam application. The patient is assumed to remain in his position throughout irradiation. Currently there is no monitoring of the patient position or organ movement during treatment. The aim of this study is to investigate the possibility of verifying the position of a fiducial marker during therapy using ion radiography. Some modern ion therapy facilities like the Heidelberg Ion-Beam Therapy Center (HIT), where our measurements were carried out, use scanning pencil beams to apply dose. Exploiting them for imaging allows to solely irradiate regions of interest in the patient's body, e.g. tissue containing medical markers. The advantage of this technique is that it can be performed quickly in turn with therapeutic beam application and irradiates only very little tissue. For our measurements we used conventional medical metal markers embedded in phantom material mimicking body tissue. To image the residual beam we use a Perkin Elmer RID256-L flat panel detector. In an idealized setup the marker contrast was measured to be as high as 60%, which was reduced by a factor of 2-2.5 when the marker was placed at distances to the detector in the phantom material larger than 10 cm. It was shown that applying 2ṡ105 carbon ions suffices to make the markers' position visible in a setup of realistic material thickness and marker depth. While the dose is comparable to X-ray imaging, the irradiated volume and, consequently, also the integral dose is considerably reduced. However, in realistic geometries there are large particle range differences in lateral direction yielding steep signal gradients in the radiography. Thus, the useful image area with unambiguous signal

  6. Accurate Position Sensing of Defocused Beams Using Simulated Beam Templates

    SciTech Connect

    Awwal, A; Candy, J; Haynam, C; Widmayer, C; Bliss, E; Burkhart, S

    2004-09-29

    In position detection using matched filtering one is faced with the challenge of determining the best position in the presence of distortions such as defocus and diffraction noise. This work evaluates the performance of simulated defocused images as the template against the real defocused beam. It was found that an amplitude modulated phase-only filter is better equipped to deal with real defocused images that suffer from diffraction noise effects resulting in a textured spot intensity pattern. It is shown that the there is a tradeoff of performance dependent upon the type and size of the defocused image. A novel automated system was developed that can automatically select the right template type and size. Results of this automation for real defocused images are presented.

  7. A Three Dimensional Beam Profile Monitor Based on Residual Gas Ionization

    SciTech Connect

    Lewis, T.A.; Shapira, D.

    1998-11-04

    A three-dimensional beam profile monitor based on tracking the ionization of the residual gas molecules in the evacuated beam pipe is described. Tracking in position and time of the ions and electrons produced in the ionization enables simultaneous position sampling in three dimensions. Special features which make it possible to sample very low beam currents were employed.

  8. Design and delivery of beam monitors for the energy-upgraded linac in J-PARC

    NASA Astrophysics Data System (ADS)

    Miura, Akihiko; Ouchi, Nobuo; Oguri, Hidetomo; Hasegawa, Kazuo; Miyao, Tomoaki; Ikegami, Masanori

    2015-02-01

    In the J-PARC (Japan Proton Accelerator Research Complex) linac, an energy-upgrade project has started to achieve a design beam power of 1 MW at the exit of the downstream synchrotron. To account for the significant beam parameter upgrades, we will use the newly-fabricated beam monitors for the beam commissioning. This paper discusses the design and assembly of the beam position monitor, phase monitor, current monitor, transverse profile monitor, and beam loss monitor for the energy-upgraded linac. We periodically installed the newly-fabricated monitors for the upgraded beam line, as well as for longitudinal matching, because of the frequency jump between the original RF cavity and the newly-developed cavity. We employed two debunchers to correct for momentum spread and jitter. To account for the new debunchers, we fabricated and installed additional pairs of phase monitors in order to tune the debunchers to the adequate RF set point. Finally, we propose commissioning plans to support the beam monitor check. We will begin to establish the 181-MeV operation to confirm the proper functioning of beam monitors. Herein, we will examine the response to changes of the knobs that control the quadrupole magnets after the energy upgrade. After proper functioning of the beam monitors is confirmed, we will use the new beam monitors to establish the 400-MeV acceleration operation.

  9. Data acquisition system for KOMAC beam monitoring using EPICS middleware

    NASA Astrophysics Data System (ADS)

    Song, Young-Gi

    2015-10-01

    The beam diagnostics instrument used to measure the beam properties is one of the important devices for the 100-MeV proton linear accelerator of the KOrea Multi-purpose Accelerator Complex (KOMAC). A data acquisition system (DAQ) is required to collect the output beam signals conditioned in the analog front-end circuitry of a beam loss monitor (BLM) and a beam position monitor (BPM). The electrical beam signal must be digitized, and the sampling has to be synchronized to a global timing system that produces a pulse signal for the pulsed beam operation. The digitized data must be accessible by the experimental physics and industrial control system (EPICS)-based control system, which manages all accelerator control. An input output controller (IOC), which runs Linux on a central process unit (CPU) module with a peripheral component interconnect (PCI) express-based Analog-to-digital converter (ADC) card, has been adopted to satisfy the requirements. An associated Linux driver and EPICS device support module have also been developed. The IOC meets the requirements, and the development and maintenance of software for the IOC is very efficient. In this paper, the details of the DAQ system for the BLM and the BPM with the introduction of the KOMAC beam-diagnostics devices, along with the performance, are described.

  10. Comment on 'Proton beam monitor chamber calibration'.

    PubMed

    Palmans, Hugo; Vatnitsky, Stanislav M

    2016-09-01

    We comment on a recent article (Gomà et al 2014 Phys. Med. Biol. 59 4961-71) which compares different routes of reference dosimetry for the energy dependent beam monitor calibration in scanned proton beams. In this article, a 3% discrepancy is reported between a Faraday cup and a plane-parallel ionization chamber in the experimental determination of the number of protons per monitor unit. It is further claimed that similar discrepancies between calorimetry and ionization chamber based dosimetry indicate that [Formula: see text]-values tabulated for proton beams in IAEA TRS-398 might be overestimated. In this commentary we show, however, that this supporting argument misrepresents the evidence in the literature and that the results presented, together with published data, rather confirm that there exist unresolved problems with Faraday cup dosimetry. We also show that the comparison in terms of the number of protons gives a biased view on the uncertainty estimates for both detectors while the quantity of interest is absorbed dose to water or dose-area-product to water, even if a beam monitor is calibrated in terms of the number of protons. Gomà et al (2014 Phys. Med. Biol. 59 4961-71) also report on the discrepancy between cylindrical and plane-parallel ionization chambers and confirm experimentally that in the presence of a depth dose gradient, theoretical values of the effective point of measurement, or alternatively a gradient correction factor, account for the discrepancy. We believe this does not point to an error or shortcoming of IAEA TRS-398, which prescribes taking the centre of cylindrical ionization chambers as reference point, since it recommends reference dosimetry to be performed in the absence of a depth dose gradient. But these observations reveal that important aspects of beam monitor calibration in scanned proton beams are not addressed in IAEA TRS-398 given that those types of beams were not widely implemented at the time of its publication

  11. The CMS Beam Halo Monitor electronics

    NASA Astrophysics Data System (ADS)

    Tosi, N.; Dabrowski, A. E.; Fabbri, F.; Grassi, T.; Hughes, E.; Mans, J.; Montanari, A.; Orfanelli, S.; Rusack, R.; Torromeo, G.; Stickland, D. P.; Stifter, K.

    2016-02-01

    The CMS Beam Halo Monitor has been successfully installed in the CMS cavern in LHC Long Shutdown 1 for measuring the machine induced background for LHC Run II. The system is based on 40 detector units composed of synthetic quartz Cherenkov radiators coupled to fast photomultiplier tubes (PMTs). The readout electronics chain uses many components developed for the Phase 1 upgrade to the CMS Hadronic Calorimeter electronics, with dedicated firmware and readout adapted to the beam monitoring requirements. The PMT signal is digitized by a charge integrating ASIC (QIE10), providing both the signal rise time, with few nanosecond resolution, and the charge integrated over one bunch crossing. The backend electronics uses microTCA technology and receives data via a high-speed 5 Gbps asynchronous link. It records histograms with sub-bunch crossing timing resolution and is read out via IPbus using the newly designed CMS data acquisition for non-event based data. The data is processed in real time and published to CMS and the LHC, providing online feedback on the beam quality. A dedicated calibration monitoring system has been designed to generate short triggered pulses of light to monitor the efficiency of the system. The electronics has been in operation since the first LHC beams of Run II and has served as the first demonstration of the new QIE10, Microsemi Igloo2 FPGA and high-speed 5 Gbps link with LHC data.

  12. RHIC BEAM LOSS MONITOR SYSTEM INITIAL OPERATION.

    SciTech Connect

    WITKOVER,R.L.; MICHNOFF,R.J.; GELLER,J.M.

    1999-03-29

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

  13. SNS Ring and RTBT Beam Current Monitor

    NASA Astrophysics Data System (ADS)

    Blokland, W.; Armstrong, G.; Deibele, C.; Pogge, J.; Gaidash, V.

    2006-11-01

    The SNS Diagnostics Group has implemented Beam Current Monitors (BCM) for the Ring and RTBT (Ring to Target Beam Transferline). In the Ring, the BCM must handle a thousand-fold increase of intensity during the accumulation, and in the RTBT, the BCM must communicate the integrated charge of the beam pulse in real-time for every shot to the target division for correlation with the produced neutrons. This paper describes the development of a four channel solution for the Ring BCM and the use of FPGA for the RTBT BCM to deliver the total charge to the target over a fiber optic network. Both system versions are based on the same commercial digitizer board.

  14. The beam optics of the Argonne Positive-Ion Injector

    SciTech Connect

    Pardo, R.C.; Shepard, K.W.; Karls, M.

    1987-01-01

    The beam optics for Phase I of the Argonne Positive-Ion Injector linac system have been studied for a representative set of beams. The results of this study indicate that high charge state beams from an ECR source can be accelerated without significantly increasing the transverse or longitudinal emittance of the initial beam. It is expected that the beam quality from the PII-ATLAS system will be at least as good as presently achieved with the tandem-ATLAS system.

  15. Intelligent mirror monitor and controller for synchrotron radiation beam lines

    SciTech Connect

    Xu, X.L.; Yang, J.

    1983-01-01

    A microprocessor-based, stand-alone mirror monitor and control system has been developed for synchrotron radiation beam lines. The operational requirements for mirror position and tilt angle, including the parameters for controlling the number of steps, direction, speed and acceleration of the driving motors, may be programmed into EPROMS. The instruction sequence to carry out critical motions will be stored in a program buffer. A manual control knob is also provided to fine tune the mirror position if desired. A synchronization scheme for the height and tilt motions maintains a fixed mirror angle during insertion. Absolute height and tilt angle are displayed. Electronic (or programmable) tilt angle limits are provided to protect against damage from misalignment of high power beams such as focussed wiggler beams. A description of mirror drives with a schematic diagram is presented. Although the controller is made for mirror movers, it can be used in other applications where multiple stepping motors perform complex synchronized motions.

  16. Photoconducting positions monitor and imaging detector

    DOEpatents

    Shu, Deming; Kuzay, Tuncer M.

    2000-01-01

    A photoconductive, high energy photon beam detector/monitor for detecting x-rays and gamma radiation, having a thin, disk-shaped diamond substrate with a first and second surface, and electrically conductive coatings, or electrodes, of a predetermined configuration or pattern, disposed on the surfaces of the substrate. A voltage source and a current amplifier is connected to the electrodes to provide a voltage bias to the electrodes and to amplify signals from the detector.

  17. Laser-based profile and energy monitor for H beams

    SciTech Connect

    Connolly,R.; Alessi, J.; Bellavia, S.; Dawson, C.; Degen, C.; Meng, W.; Raparia, D.; Russo, T.; Tsoupas, N.

    2008-09-29

    A beam profile and energy monitor for H{sup -} beams based on laser photoneutralization was built at Brookhaven National Laboratory (BNL)* for use on the High Intensity Neutrino Source (HMS) at Fermilab. An H{sup -} ion has a first ionization potential of 0.75eV and can be neutralized by light from a Nd:YAG laser ({lambda}=1064nm). To measure beam profiles, a narrow laser beam is stepped across the ion beam, removing electrons from the portion of the H{sup -} beam intercepted by the laser. These electrons are channeled into a Faraday cup by a curved axial magnetic field. To measure the energy distribution of the electrons, the laser position is fixed and the voltage on a screen in front of the Faraday cup is raised in small steps. We present a model which reproduces the measured energy spectrum from calculated beam energy and space-charge fields. Measurements are reported from experiments in the BNL linac MEBT at 750keV.

  18. RHIC beam loss monitor system design

    SciTech Connect

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

    1997-07-01

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

  19. High power laser beam delivery monitoring for laser safety

    NASA Astrophysics Data System (ADS)

    Corder, D. A.; Evans, D. R.; Tyrer, J. R.; Freeland, C. M.; Myler, J. K.

    1997-07-01

    The output of high power lasers used for material processing presents extreme radiation hazards. In normal operation this hazard is removed by the use of local shielding to prevent accidental exposure and system design to ensure efficient coupling of radiation into the workpiece. Faults in laser beam delivery or utilization can give rise to hazardous levels of laser radiation. A passive hazard control strategy requires that the laser system be enclosed such that the full laser power cannot burn through the housing under fault conditions. Usually this approach is too restrictive. Instead, active control strategies can be used in which a fault condition is detected and the laser cut off. This reduces the requirements for protective housing. In this work a distinction is drawn between reactive and proactive strategies. Reactive strategies rely on detecting the effects of an errant laser beam, whereas proactive strategies can anticipate as well as detect fault conditions. This can avoid the need for a hazardous situation to exist. A proactive strategy in which the laser beam is sampled at the final turning mirror is described in this work. Two control systems have been demonstrated; the first checks that beam power is within preset limits, the second monitors incoming beam power and position, and the radiation reflected back from the cutting head. In addition to their safety functions the accurate monitoring of power provides an additional benefit to the laser user.

  20. The AGS Booster beam loss monitor system

    SciTech Connect

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

    1991-01-01

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

  1. The ATLAS Diamond Beam Monitor: Luminosity detector at the LHC

    NASA Astrophysics Data System (ADS)

    Schaefer, D. M.

    2016-07-01

    After the first three years of the LHC running, the ATLAS experiment extracted its 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 install a set of beam monitoring telescopes with pixel sensors, four each in the forward and backward regions. These telescopes are based on chemical vapor deposited (CVD) diamond sensors to survive in this high radiation environment without needing extensive cooling. This paper describes the lessons learned in construction and commissioning of the ATLAS Diamond Beam Monitor (DBM). We show results from the construction quality assurance tests and commissioning performance, including results from cosmic ray running in early 2015.

  2. Method and apparatus for monitoring the power of a laser beam

    DOEpatents

    Paris, R.D.; Hackel, R.P.

    1996-02-06

    A method for monitoring the power of a laser beam in real time is disclosed. At least one optical fiber is placed through the laser beam, where a portion of light from the laser beam is coupled into the optical fiber. The optical fiber may be maintained in a stationary position or moved periodically over a cross section of the laser beam to couple light from each area traversed. Light reaching both fiber ends is monitored according to frequency and processed to determine the power of the laser beam. 6 figs.

  3. Method and apparatus for monitoring the power of a laser beam

    DOEpatents

    Paris, Robert D.; Hackel, Richard P.

    1996-01-01

    A method for monitoring the power of a laser beam in real time is disclosed. At least one optical fiber is placed through the laser beam, where a portion of light from the laser beam is coupled into the optical fiber. The optical fiber may be maintained in a stationary position or moved periodically over a cross section of the laser beam to couple light from each area traversed. Light reaching both fiber ends is monitored according to frequency and processed to determine the power of the laser beam.

  4. AN INVESTIGATION OF THE BEAM MONITOR FOR THE CLUSTER KLYSTRON.

    SciTech Connect

    ZHAO,Y.

    2001-08-21

    The cluster klystron project required a beam monitor to check the quality of the hollow beam shape. Since the power density of the beam is very large, a common phosphorescent screen doesn't work. We investigated varies types of monitors. The related problems were also discussed.

  5. 21 CFR 892.5780 - Light beam patient position indicator.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Light beam patient position indicator. 892.5780 Section 892.5780 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... beam of light is intended to be used during radiologic procedures to ensure proper positioning of...

  6. Point Positioning Service for Natural Hazard Monitoring

    NASA Astrophysics Data System (ADS)

    Bar-Sever, Y. E.

    2014-12-01

    In an effort to improve natural hazard monitoring, JPL has invested in updating and enlarging its global real-time GNSS tracking network, and has launched a unique service - real-time precise positioning for natural hazard monitoring, entitled GREAT Alert (GNSS Real-Time Earthquake and Tsunami Alert). GREAT Alert leverages the full technological and operational capability of the JPL's Global Differential GPS System [www.gdgps.net] to offer owners of real-time dual-frequency GNSS receivers: Sub-5 cm (3D RMS) real-time, absolute positioning in ITRF08, regardless of location Under 5 seconds turnaround time Full covariance information Estimates of ancillary parameters (such as troposphere) optionally provided This service enables GNSS networks operators to instantly have access to the most accurate and reliable real-time positioning solutions for their sites, and also to the hundreds of participating sites globally, assuring inter-consistency and uniformity across all solutions. Local authorities with limited technical and financial resources can now access to the best technology, and share environmental data to the benefit of the entire pacific region. We will describe the specialized precise point positioning techniques employed by the GREAT Alert service optimized for natural hazard monitoring, and in particular Earthquake monitoring. We address three fundamental aspects of these applications: 1) small and infrequent motion, 2) the availability of data at a central location, and 3) the need for refined solutions at several time scales

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

    NASA Astrophysics Data System (ADS)

    Wang, Fuhua; Mao, Naifeng

    1993-12-01

    A beam transport line error analysis and beam position correction code called ``EAC'' has been enveloped associated 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, systematic and statistical errors of magnetic fields as well as the effects of the initial beam positions, on the central trajectory and upon 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 such as the beam line geometrical layout, plots of the Twiss parameters, beam envelopes, etc. It also generates an EAC input file, thus connecting EAC with general optics codes. EAC and the post processing package are small size codes, that are easy to access and use. They have become useful tools for the design of transport lines at SSCL.

  8. A submicronic beam size monitor for the final focus test beam

    SciTech Connect

    Puzo, P.; Buon, J.; Jeanjean, J.; LeDiberder, F. |; Lepeltier, V.

    1997-01-01

    A gas-ionization beam size monitor has been used to optimize and measure the transverse electron beam dimensions of the Final Focus Test Beam at SLAC. The ultimate values measured with the monitor are 1.5{mu}m{times}70nm. Moreover, the high sensitivity of the monitor has been used to detect and cancel detrimental {open_quote}banana{close_quote} shapes of the beam. {copyright} {ital 1997 American Institute of Physics.}

  9. The CMS Beam Conditions and Radiation Monitoring System

    NASA Astrophysics Data System (ADS)

    Castro, E.; Bacchetta, N.; Bell, A. J.; Dabrowski, A.; Guthoff, M.; Hall-Wilton, R.; Hempel, M.; Henschel, H.; Lange, W.; Lohmann, W.; Müller, S.; Novgorodova, O.; Pfeiffer, D.; Ryjov, V.; Stickland, D.; Schimdt, R.; Walsh, R.

    The Compact Muon Solenoid (CMS) is one of the two large, general purpose experiments situated at the LHC at CERN. As with all high energy physics experiments, knowledge of the beam conditions and luminosity is of vital importance. The Beam Conditions and Radiation Monitoring System (BRM) is installed in CMS to protect the detector and to provide feedback to LHC on beam conditions. It is composed of several sub-systems that measure the radiation level close to or inside all sub-detectors, monitor the beam halo conditions with different time resolution, support beam tuning and protect CMS in case of adverse beam conditions by firing a beam abort signal. This paper presents three of the BRM subsystems: the Fast Beam Conditions Monitor (BCM1F), which is designed for fast flux monitoring, measuring with nanosecond time resolution, both the beam halo and collision products; the Beam Scintillator Counters (BSC), that provide hit rates and time information of beam halo and collision products; and the Beam Conditions Monitors (BCM) used as a protection system that can trigger a beam dump when beam losses occur in order to prevent damage to the pixel and tracker detectors. A description of the systems and a characterization on the basis of data collected during LHC operation is presented.

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

    SciTech Connect

    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.

  11. Characterization of the Li beam probe with a beam profile monitor on JETa)

    NASA Astrophysics Data System (ADS)

    Nedzelskiy, I. S.; Korotkov, A.; Brix, M.; Morgan, P.; Vince, J.; Jet Efda Contributors

    2010-10-01

    The lithium beam probe (LBP) is widely used for measurements of the electron density in the edge plasma of magnetically confined fusion experiments. The quality of LBP data strongly depends on the stability and profile shape of the beam. The main beam parameters are as follows: beam energy, beam intensity, beam profile, beam divergence, and the neutralization efficiency. For improved monitoring of the beam parameters, a beam profile monitor (BPM) from the National Electrostatics Corporation (NEC) has been installed in the Li beam line at JET. In the NEC BPM, a single grounded wire formed into a 45° segment of a helix is rotated by a motor about the axis of the helix. During each full revolution, the wire sweeps twice across the beam to give X and Y profiles. In this paper, we will describe the properties of the JET Li beam as measured with the BPM and demonstrate that it facilitates rapid optimization of the gun performance.

  12. Characterization of the Li beam probe with a beam profile monitor on JET

    SciTech Connect

    Nedzelskiy, I. S.; Collaboration: JET EFDA Contributors

    2010-10-15

    The lithium beam probe (LBP) is widely used for measurements of the electron density in the edge plasma of magnetically confined fusion experiments. The quality of LBP data strongly depends on the stability and profile shape of the beam. The main beam parameters are as follows: beam energy, beam intensity, beam profile, beam divergence, and the neutralization efficiency. For improved monitoring of the beam parameters, a beam profile monitor (BPM) from the National Electrostatics Corporation (NEC) has been installed in the Li beam line at JET. In the NEC BPM, a single grounded wire formed into a 45 deg. segment of a helix is rotated by a motor about the axis of the helix. During each full revolution, the wire sweeps twice across the beam to give X and Y profiles. In this paper, we will describe the properties of the JET Li beam as measured with the BPM and demonstrate that it facilitates rapid optimization of the gun performance.

  13. Development of a Negative Hydrogen Ion Source for Spatial Beam Profile Measurement of a High Intensity Positive Ion Beam

    SciTech Connect

    Shinto, Katsuhiro; Wada, Motoi; Nishida, Tomoaki; Demura, Yasuhiro; Sasaki, Daichi; Tsumori, Katsuyoshi; Nishiura, Masaki; Kaneko, Osamu; Kisaki, Masashi; Sasao, Mamiko

    2011-09-26

    We have been developing a negative hydrogen ion (H{sup -} ion) source for a spatial beam profile monitor of a high intensity positive ion beam as a new diagnostic tool. In case of a high intensity continuous-wave (CW) deuteron (D{sup +}) beam for the International Fusion Materials Irradiation Facility (IFMIF), it is difficult to measure the beam qualities in the severe high radiation environment during about one-year cyclic operation period. Conventional techniques are next to unusable for diagnostics in the operation period of about eleven months and for maintenance in the one-month shutdown period. Therefore, we have proposed an active beam probe system by using a negative ion beam and started an experimental study for the proof-of-principle (PoP) of the new spatial beam profile monitoring tool. In this paper, we present the status of development of the H{sup -} ion source as a probe beam source for the PoP experiment.

  14. A multi-wire beam profile monitor in the AGS

    SciTech Connect

    Huang, H.; Buxton, W.; Castillo, V.; Glenn, J.W.

    1997-07-01

    A multi-wire beam profile monitor which can be used to directly monitor and control the optical matching between the Booster and AGS rings has been installed and tested in the AGS. Placement of a multi-wire monitor directly in the AGS provides profile measurements taken upon injection and the first two or more revolutions of the beam. The data from such measurements can be used to determine the optical properties of the beam transport line leading into the AGS.

  15. Preservation of beam loss induced quenches, beam lifetime and beam loss measurements with the HERAp beam-loss-monitor system

    NASA Astrophysics Data System (ADS)

    Wittenburg, Kay

    1994-06-01

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

  16. Operation of the NuMI beam monitoring system

    SciTech Connect

    Zwaska, Robert M.; Indurthy, Dharma; Keisler, Ryan; Kopp, Sacha; Mendoza, Steven; Pavlovich, Zarko; Proga, Marek; Bishai, Mary; Diwan, Milind; Viren, Brett; Harris, Deborah A.; Marchionni, Alberto; Morfin, Jorge; McDonald, Jeffrey; Naples, Donna; Northacker, David; Erwin, Albert; Ping, Huican; Velissaris, Cristos; /Texas U. /Brookhaven /Fermilab /Pittsburgh U. /Wisconsin U., Madison

    2006-06-01

    The NuMI (Neutrinos at the Main Injector) facility produces an intense neutrino beam for experiments. The NuMI Beam Monitoring system is four arrays of ion chambers that measure the intensity and distribution of the remnant hadron and tertiary muon beams produced in association with the neutrinos. The ion chambers operate in an environment of high particle fluxes and high radiation.

  17. Summary Report on Beam and Radiation Generation, Monitoring and Control

    SciTech Connect

    Gordon, D. F.; Power, J. G.

    2009-01-22

    The discussions of the working group on beam and radiation generation, monitoring, and control (working group 6) at the 2008 advanced accelerator concepts workshop are summarized. The discussions concerned electron injectors, phase space manipulation, beam diagnostics, pulse train generation, intense beam physics, and radiation generation.

  18. High sensitivity charge amplifier for ion beam uniformity monitor

    DOEpatents

    Johnson, Gary W.

    2001-01-01

    An ion beam uniformity monitor for very low beam currents using a high-sensitivity charge amplifier with bias compensation. The ion beam monitor is used to assess the uniformity of a raster-scanned ion beam, such as used in an ion implanter, and utilizes four Faraday cups placed in the geometric corners of the target area. Current from each cup is integrated with respect to time, thus measuring accumulated dose, or charge, in Coulombs. By comparing the dose at each corner, a qualitative assessment of ion beam uniformity is made possible. With knowledge of the relative area of the Faraday cups, the ion flux and areal dose can also be obtained.

  19. Positive and negative ion beam merging system for neutral beam production

    DOEpatents

    Leung, Ka-Ngo; Reijonen, Jani

    2005-12-13

    The positive and negative ion beam merging system extracts positive and negative ions of the same species and of the same energy from two separate ion sources. The positive and negative ions from both sources pass through a bending magnetic field region between the pole faces of an electromagnet. Since the positive and negative ions come from mirror image positions on opposite sides of a beam axis, and the positive and negative ions are identical, the trajectories will be symmetrical and the positive and negative ion beams will merge into a single neutral beam as they leave the pole face of the electromagnet. The ion sources are preferably multicusp plasma ion sources. The ion sources may include a multi-aperture extraction system for increasing ion current from the sources.

  20. Development of a fast position-sensitive laser beam detector

    SciTech Connect

    Chavez, Isaac; Huang Rongxin; Henderson, Kevin; Florin, Ernst-Ludwig; Raizen, Mark G.

    2008-10-15

    We report the development of a fast position-sensitive laser beam detector. The detector uses a fiber-optic bundle that spatially splits the incident beam, followed by a fast balanced photodetector. The detector is applied to the study of Brownian motion of particles on fast time scales with 1 A spatial resolution. Future applications include the study of molecule motors, protein folding, as well as cellular processes.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    SciTech Connect

    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

    2015-11-03

    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. We found that 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. Finally, the calculated beam position will be used in the data analysis to accurately determine the kinematics for each event.

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

    DOE PAGES

    Zhu, Pengjia; Allada, Kalyan; Allison, Trent; Badman, Toby; Camsonne, Alexandre; Chen, Jian-ping; Cummings, Melissa; Gu, Chao; Huang, Min; Liu, Jie; et al

    2015-11-03

    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. We found that before and during the experiment, these new devices were tested and debugged, and their performance was also evaluated. In order to achieve themore » 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. Finally, the calculated beam position will be used in the data analysis to accurately determine the kinematics for each event.« less

  4. A micro-pattern gaseous detector for beam monitoring in ion-therapy

    NASA Astrophysics Data System (ADS)

    Terakawa, A.; Ishii, K.; Matsuyama, S.; Kikuchi, Y.; Togashi, T.; Arikawa, J.; Yamashita, W.; Takahashi, Y.; Fujishiro, F.; Yamazaki, H.; Sakemi, Y.

    2015-12-01

    A micro-pattern gaseous detector based on gas electron multiplier technology (GEM detector) was developed as a new transmission beam monitor for charged-particle therapy to obtain real-time information about the parameters of a therapeutic beam. Feasibility tests for the GEM detector were performed using an 80-MeV proton beam to evaluate the lateral intensity distributions of a pencil beam and the dose delivered to a target. The beam intensity distributions measured with the GEM detector were in good agreement with those measured with an imaging plate while the charge output from the GEM detector was in proportion to that of a reference dose monitor of an ionization chamber design. These experimental results showed that the GEM detector can be used not only as a beam monitor for the position and two-dimensional intensity distribution but also as a dose monitor. Thus, it is possible to simultaneously measure these beam parameters for beam control in charged-particle therapy using a single GEM-based transmission monitor.

  5. Precision neutron flux measurement with a neutron beam monitor

    NASA Astrophysics Data System (ADS)

    Ino, T.; Otono, H.; Mishima, K.; Yamada, T.

    2014-07-01

    Neutron beam monitors are regularly used in various neutron beam experiments to compare two or more sets of data taken in different experimental conditions. A neutron lifetime experiment at BL05, the NOP beamline, in J-PARC requires to monitor the initial neutron intensity with an precision of 0.1% to measure the neutron lifetime with the same accuracy. The performance of a thin 3He gas neutron beam monitor used for the experiment was studied to estimate the systematic uncertainties in the neutron lifetime measurement.

  6. Overview of nonintercepting beam-size monitoring with optical diffraction radiation

    SciTech Connect

    Lumpkin, Alex H.; /Fermilab

    2010-08-01

    The initial demonstrations over the last several years of the use of optical diffraction radiation (ODR) as nonintercepting electron-beam-parameter monitors are reviewed. Developments in both far-field imaging and near-field imaging are addressed for ODR generated by a metal plane with a slit aperture, a single metal plane, and two-plane interferences. Polarization effects and sensitivities to beam size, divergence, and position will be discussed as well as a proposed path towards monitoring 10-micron beam sizes at 25 GeV.

  7. Active beam position stabilization of pulsed lasers for long-distance ion profile diagnostics at the Spallation Neutron Source (SNS).

    PubMed

    Hardin, Robert A; Liu, Yun; Long, Cary; Aleksandrov, Alexander; Blokland, Willem

    2011-02-14

    A high peak-power Q-switched laser has been used to monitor the ion beam profiles in the superconducting linac at the Spallation Neutron Source (SNS). The laser beam suffers from position drift due to movement, vibration, or thermal effects on the optical components in the 250-meter long laser beam transport line. We have designed, bench-tested, and implemented a beam position stabilization system by using an Ethernet CMOS camera, computer image processing and analysis, and a piezo-driven mirror platform. The system can respond at frequencies up to 30 Hz with a high position detection accuracy. With the beam stabilization system, we have achieved a laser beam pointing stability within a range of 2 μrad (horizontal) to 4 μrad (vertical), corresponding to beam drifts of only 0.5 mm × 1 mm at the furthest measurement station located 250 meters away from the light source.

  8. Active beam position stabilization of pulsed lasers for long-distance ion profile diagnostics at the Spallation Neutron Source (SNS)

    SciTech Connect

    Hardin, Robert A; Liu, Yun; Long, Cary D; Aleksandrov, Alexander V; Blokland, Willem

    2011-01-01

    A high peak-power Q-switched laser has been used to monitor the ion beam profiles in the superconducting linac at the Spallation Neutron Source (SNS). The laser beam suffers from position drift due to movement, vibration, or thermal effects on the optical components in the 250-meter long laser beam transport line. We have designed, bench-tested, and implemented a beam position stabilization system by using an Ethernet CMOS camera, computer image processing and analysis, and a piezo-driven mirror platform. The system can respond at frequencies up to 30 Hz with a high position detection accuracy. With the beam stabilization system, we have achieved a laser beam pointing stability within a range of 2 rad (horizontal) to 4 rad (vertical), corresponding to beam drifts of only 0.5 mm 1 mm at the furthest measurement station located 250 meters away from the light source.

  9. The new bern PET cyclotron, its research beam line, and the development of an innovative beam monitor detector

    NASA Astrophysics Data System (ADS)

    Braccini, Saverio

    2013-04-01

    The new Bern cyclotron laboratory aims at industrial radioisotope production for PET diagnostics and multidisciplinary research by means of a specifically conceived beam transfer line, terminated in a separate bunker. In this framework, an innovative beam monitor detector based on doped silica and optical fibres has been designed, constructed, and tested. Scintillation light produced by Ce and Sb doped silica fibres moving across the beam is measured, giving information on beam position, shape, and intensity. The doped fibres are coupled to commercial optical fibres, allowing the read-out of the signal far away from the radiation source. This general-purpose device can be easily adapted for any accelerator used in medical applications and is suitable either for low currents used in hadrontherapy or for currents up to a few μA for radioisotope production, as well as for both pulsed and continuous beams.

  10. The new bern PET cyclotron, its research beam line, and the development of an innovative beam monitor detector

    SciTech Connect

    Braccini, Saverio

    2013-04-19

    The new Bern cyclotron laboratory aims at industrial radioisotope production for PET diagnostics and multidisciplinary research by means of a specifically conceived beam transfer line, terminated in a separate bunker. In this framework, an innovative beam monitor detector based on doped silica and optical fibres has been designed, constructed, and tested. Scintillation light produced by Ce and Sb doped silica fibres moving across the beam is measured, giving information on beam position, shape, and intensity. The doped fibres are coupled to commercial optical fibres, allowing the read-out of the signal far away from the radiation source. This general-purpose device can be easily adapted for any accelerator used in medical applications and is suitable either for low currents used in hadrontherapy or for currents up to a few {mu}A for radioisotope production, as well as for both pulsed and continuous beams.

  11. A new luminescence beam profile monitor for intense proton and heavy ion beams

    SciTech Connect

    Tsang,T.; Bellavia, S.; Connolly, R.; Gassner, D.; Makdisi, Y.; Russo, T.; Thieberger, P.; Trbojevic, D.; Zelenski, A.

    2008-10-01

    A new luminescence beam profile monitor is realized in the polarized hydrogen gas jet target at the Relativistic Heavy Ion Collider (RHIC) facility. In addition to the spin polarization of the proton beam being routinely measured by the hydrogen gas jet, the luminescence produced by beam-hydrogen excitation leads to a strong Balmer series lines emission. A selected hydrogen Balmer line is spectrally filtered and imaged to produce the transverse RHIC proton beam shape with unprecedented details on the RHIC beam profile. Alternatively, when the passage of the high energy RHIC gold ion beam excited only the residual gas molecules in the beam path, sufficient ion beam induced luminescence is produced and the transverse gold ion beam profile is obtained. The measured transverse beam sizes and the calculated emittances provide an independent confirmation of the RHIC beam characteristics and to verify the emittance conservation along the RHIC accelerator. This optical beam diagnostic technique by making use of the beam induced fluorescence from injected or residual gas offers a truly noninvasive particle beam characterization, and provides a visual observation of proton and heavy ion beams. Combined with a longitudinal bunch measurement system, a 3-dimensional spatial particle beam profile can be reconstructed tomographically.

  12. CCD based beam loss monitor for ion accelerators

    NASA Astrophysics Data System (ADS)

    Belousov, A.; Mustafin, E.; Ensinger, W.

    2014-04-01

    Beam loss monitoring is an important aspect of proper accelerator functioning. There is a variety of existing solutions, but each has its own disadvantages, e.g. unsuitable dynamic range or time resolution, high cost, or short lifetime. Therefore, new options are looked for. This paper shows a method of application of a charge-coupled device (CCD) video camera as a beam loss monitor (BLM) for ion beam accelerators. The system was tested with a 500 MeV/u N+7 ion beam interacting with an aluminum target. The algorithms of camera signal processing with LabView based code and beam loss measurement are explained. Limits of applicability of this monitor system are discussed.

  13. Operation of the NuMI Beam Monitoring System

    SciTech Connect

    Zwaska, Robert M.; Indurthy, Dharma; Keisler, Ryan; Kopp, Sacha; Mendoza, Steven; Pavlovich, Zarko; Proga, Marek; Bishai, Mary; Diwan, Milind; Viren, Brett; Harris, Debbie; Marchionni, Alberto; Morfin, Jorge; McDonald, Jeffrey; Naples, Donna; Northacker, David; Erwin, Albert; Ping, Huican; Velissaris, Cristos

    2006-11-20

    The NuMI (Neutrinos at the Main Injector) facility produces an intense neutrino beam for experiments. The NuMI Beam Monitoring system consists of four arrays of ion chambers that measure the intensity and distribution of the remnant hadron and tertiary muon beams produced in association with the neutrinos. The ion chambers operate in an environment of high particle fluxes and high radiation.

  14. On the detector arrangement for in-beam PET for hadron therapy monitoring.

    PubMed

    Crespo, Paulo; Shakirin, Georgy; Enghardt, Wolfgang

    2006-05-01

    In-beam positron emission tomography (in-beam PET) is currently the only method for an in situ monitoring of highly tumour-conformed charged hadron therapy. At the experimental carbon ion tumour therapy facility, running at the Gesellschaft für Schwerionenforschung, Darmstadt, Germany, all treatments have been monitored by means of a specially adapted dual-head PET scanner. The positive clinical impact of this project triggered the construction of a hospital-based hadron therapy facility, with in-beam PET expected to monitor more delicate radiotherapeutic situations. Therefore, we have studied possible in-beam PET improvements by optimizing the arrangement of the gamma-ray detectors. For this, a fully 3D, rebinning-free, maximum likelihood expectation maximization algorithm applicable to several closed-ring or dual-head tomographs has been developed. The analysis of beta(+)-activity distributions simulated from real-treatment situations and detected with several detector arrangements allows us to conclude that a dual-head tomograph with narrow gaps yields in-beam PET images with sufficient quality for monitoring head and neck treatments. For monitoring larger irradiation fields, e.g. treatments in the pelvis region, a closed-ring tomograph was seen to be highly desirable. Finally, a study of the space availability for patient and bed, tomograph and beam portal proves the implementation of a closed-ring detector arrangement for in-beam PET to be feasible. PMID:16625032

  15. Wire Position Monitoring with FPGA based Electronics

    SciTech Connect

    Eddy, N.; Lysenko, O.; /Fermilab

    2009-01-01

    This fall the first Tesla-style cryomodule cooldown test is being performed at Fermilab. Instrumentation department is preparing the electronics to handle the data from a set of wire position monitors (WPMs). For simulation purposes a prototype pipe with a WMP has been developed and built. The system is based on the measurement of signals induced in pickups by 320 MHz signal carried by a wire through the WPM. The wire is stretched along the pipe with a tensioning load of 9.07 kg. The WPM consists of four 50 {Omega} striplines spaced 90{sup o} apart. FPGA based digitizer scans the WPM and transmits the data to a PC via VME interface. The data acquisition is based on the PC running LabView. In order to increase the accuracy and convenience of the measurements some modifications were required. The first is implementation of an average and decimation filter algorithm in the integrator operation in the FPGA. The second is the development of alternative tool for WPM measurements in the PC. The paper describes how these modifications were performed and test results of a new design. The last cryomodule generation has a single chain of seven WPMs (placed in critical positions: at each end, at the three posts and between the posts) to monitor a cold mass displacement during cooldown. The system was developed in Italy in collaboration with DESY. Similar developments have taken place at Fermilab in the frame of cryomodules construction for SCRF research. This fall preliminary cryomodule cooldown test is being performed. In order to prepare an appropriate electronic system for the test a prototype pipe with a WMP has been developed and built, figure 1. The system is based on the measurement of signals induced in pickups by 320 MHz signal carried by a wire through the WPM. The 0.5 mm diameter Cu wire is stretched along the pipe with a tensioning load of 9.07 kg and has a length of 1.1 m. The WPM consists of four 50 {Omega} striplines spaced 90{sup o} apart. An FPGA based

  16. Precision analog signal processor for beam position measurements in electron storage rings

    SciTech Connect

    Hinkson, J.A.; Unser, K.B.

    1995-05-01

    Beam position monitors (BPM) in electron and positron storage rings have evolved from simple systems composed of beam pickups, coaxial cables, multiplexing relays, and a single receiver (usually a analyzer) into very complex and costly systems of multiple receivers and processors. The older may have taken minutes to measure the circulating beam closed orbit. Today instrumentation designers are required to provide high-speed measurements of the beam orbit, often at the ring revolution frequency. In addition the instruments must have very high accuracy and resolution. A BPM has been developed for the Advanced Light Source (ALS) in Berkeley which features high resolution and relatively low cost. The instrument has a single purpose; to measure position of a stable stored beam. Because the pickup signals are multiplexed into a single receiver, and due to its narrow bandwidth, the receiver is not intended for single-turn studies. The receiver delivers normalized measurements of X and Y posit ion entirely by analog means at nominally 1 V/mm. No computers are involved. No software is required. Bergoz, a French company specializing in precision beam instrumentation, integrated the ALS design m their new BPM analog signal processor module. Performance comparisons were made on the ALS. In this paper we report on the architecture and performance of the ALS prototype BPM.

  17. The fiber-SiPMT beam monitor of the R484 experiment at the RIKEN-RAL muon facility

    NASA Astrophysics Data System (ADS)

    Carbone, R.; Bonesini, M.; Bertoni, R.; Mazza, R.; Rossella, M.; Tortora, L.; Vacchi, A.; Vallazza, E.; Zampa, G.

    2015-03-01

    The scintillating fibers SiPM based beam monitor detector, designed to deliver position, shape and timing of the low energy muon beam at the RIKEN-RAL muon facility for the R484 experiment, has been successfully tested on the electron beam at the Beam Test Facility (BTF) of the INFN LNF laboratories. We report here the lay out and the read out structure as well as the very promising results.

  18. High-resolution phosphor screen beam profile monitor

    SciTech Connect

    Yencho, S.; Walz, D.R.

    1985-05-01

    A high-resolution luminescent screen beam profile monitor was developed to allow viewing of both conventional large diameter SLAC e/sup +//e/sup -/ beams, and also collider rf-bunches having small transverse spatial extent, with one instrument. The principal features of the monitor are described. They include the two-power magnification system offering magnifications of 12 and 78X, respectively; the reticle grid which is optically superimposed on the screen image by a cube beam splitter; selection of a suitable camera; and the Al/sub 2/O/sub 3/(Cr) phosphor screen. A simplified version of the monitor for viewing of only micron-sized beams for applications in the collider arcs and final focus regions and achieving a magnification of approx. 40X, coupled with a resolution of approx. 20..mu..m is also presented. 4 refs., 4 figs.

  19. A high-resolution phosphor screen beam profile monitor

    SciTech Connect

    Yencho, S.; Walz, D.R.

    1985-10-01

    A high-resolution luminescent screen beam profile monitor was developed to allow viewing of both conventional large diameter SLAC e/sup +//e/sup -/ beams, and also collider rf-bunches having small transverse spatial extent, with one instrument. The principal features of the monitor are described. They include the two-power magnification system offering magnifications of 12 and 78X, respectively; the reticle grid which is optically superimposed on the screen image by a cube beam splitter; selection of a suitable camera; and the Al/sub 2/O/sub 3/(Cr) phosphor screen. A simplified version of the monitor for viewing of only micronsized beams for applications in the collider arcs and final focus regions and achieving a magnification of about40X, coupled with a resolution of about20..mu..m is also presented.

  20. The development of beam current monitors in the APS

    SciTech Connect

    Wang, X.; Lenkszus, F.; Rotela, E.

    1995-07-01

    The Advanced Photon Source (APS) is a third-generation 7-GeV synchrotron radiation source. The precision measurement of beam current is a challenging task in high energy accelerators, such as the APS, with a wide range of beam parameters and complicated noise, radiation, and thermal environments. The beam pulses in the APS injector and storage ring have charge ranging from 50pC to 25nC with pulse durations varying from 30ps to 30ns. A total of nine non- intercepting beam current monitors have been installed in the APS facility (excluding those in the linac) for general current measurement. In addition, several independent current monitors with specially designed redundant interlock electronics are installed for personnel safety and machine protection. This paper documents the design and development of current monitors in the APS,. discusses the commissioning experience in the past year, and presents the results of recent operations.

  1. LASER-BASED PROFILE MONITOR FOR ELECTRON BEAMS

    SciTech Connect

    Ross, Marc C

    2003-05-27

    High performance TeV energy electron / positron colliders (LC) are the first machines to require online, non-invasive beam size monitors for micron and sub-micron for beam phase space optimization. Typical beam densities in the LC are well beyond the threshold density for single pulse melting and vaporization of any material, making conventional wire scanners ineffective. Using a finely focused, diffraction limited high power laser, it is possible to devise a sampling profile monitor that, in operation, resembles a wire scanner. Very high resolution laser-based profile monitors have been developed and tested, first at FFTB (SLAC) and later at SLC and ATF. The monitor has broad applicability and we review here the technology, application and status of ongoing research programs.

  2. Using time separation of signals to obtain independent proton and antiproton beam position measurements around the Tevatron

    SciTech Connect

    Webber, R.; /Fermilab

    2005-05-01

    Independent position measurement of the counter-circulating proton and antiproton beams in the Tevatron, never supported by the original Tevatron Beam Position Monitor (BPM) system, presents a challenge to upgrading that system. This paper discusses the possibilities and complications of using time separation of proton and antiproton signals at the numerous BPM locations and for the dynamic Tevatron operating conditions. Results of measurements using one such method are presented.

  3. Ultraviolet laser beam monitor using radiation responsive crystals

    DOEpatents

    McCann, Michael P.; Chen, Chung H.

    1988-01-01

    An apparatus and method for monitoring an ultraviolet laser beam includes disposing in the path of an ultraviolet laser beam a substantially transparent crystal that will produce a color pattern in response to ultraviolet radiation. The crystal is exposed to the ultraviolet laser beam and a color pattern is produced within the crystal corresponding to the laser beam intensity distribution therein. The crystal is then exposed to visible light, and the color pattern is observed by means of the visible light to determine the characteristics of the laser beam that passed through crystal. In this manner, a perpendicular cross sectional intensity profile and a longitudinal intensity profile of the ultraviolet laser beam may be determined. The observation of the color pattern may be made with forward or back scattered light and may be made with the naked eye or with optical systems such as microscopes and television cameras.

  4. High power beam profile monitor with optical transition radiation

    SciTech Connect

    Denard, J.C.; Piot, P.; Capek, K.; Feldl, E.

    1997-06-01

    A simple monitor has been built to measure the profile of the high power beam (800 kW) delivered by the CEBAF accelerator at Jefferson Lab. The monitor uses the optical part of the forward transition radiation emitted from a thin carbon foil. The small beam size to be measured, about 100 {mu}m, is challenging not only for the power density involved but also for the resolution the instrument must achieve. An important part of the beam instrumentation community believes the radiation being emitted into a cone of characteristic angle 1/{gamma} is originated from a region of transverse dimension roughly {lambda}{gamma}; thus the apparent size of the source of transition radiation would become very large for highly relativistic particles. This monitor measures 100 {mu}m beam sizes that are much smaller than the 3.2 mm {lambda}{gamma} limit; it confirms the statement of Rule and Fiorito that optical transition radiation can be used to image small beams at high energy. The present paper describes the instrument and its performance. The authors tested the foil in, up to 180 {mu}A of CW beam without causing noticeable beam loss, even at 800 MeV, the lowest CEBAF energy.

  5. Plasmonic quadrant lens for beam-position sensing.

    PubMed

    Wang, Jiayuan; Yang, Jing; Bai, Zhenjian; Zhang, Jiasen

    2016-09-19

    We present the design of a plasmonic quadrant lens (QL) which is capable of coupling the light from free space into surface plasmon polaritons (SPPs) and focusing them into four directions, depending on the polarization content of the incident light. The lens is composed of a set of uniform nanogrooves etched on a gold film. Two types of QLs with four and eight foci are realized. We further propose QLs as a plasmonic version of well-known quadrant detectors for beam-position sensing through a center location algorithm. The sensitivity of the device is also investigated for both linear and circular polarized incidences. Calculation results show that the four-focus QL offers a large effective detecting area and the eight-focus QL enables beam-position sensing to be operated with two different sensitivities simultaneously. PMID:27661895

  6. Method to eliminate the impact of magnetic fields on the position of the electron beam during EBW

    NASA Astrophysics Data System (ADS)

    Laptenok, V. D.; Druzhinina, A. A.; Murygin, A. V.; Seregin, Yu N.

    2016-04-01

    The paper presents the approximate formulas for calculating the deflection angle and the misalignment of the electron beam from the optical axis of the electron gun caused by the action of magnetic fields during the electron beam welding. Mathematical model of the effect of magnetic field induced by thermoelectric currents on the electron beam position in the process of electron beam welding of dissimilar materials is presented. The method of monitoring of the misalignment of the scanning electron beam and its mathematical model are proposed. Monitoring of the misalignment of the scanning electron beam is based on the processing of the signal of the collimated X-ray sensor directed to the optical axis of the electron gun by synchronous detection method. The method of compensation of the effect of magnetic fields by passing through the welded seam the currents which compensate thermoelectric currents is considered.

  7. Precision monitoring of relative beam intensity for Mu2e

    SciTech Connect

    Evans, N.J.; Kopp, S.E.; Prebys, E.; /Fermilab

    2011-04-01

    For future experiments at the intensity frontier, precise and accurate knowledge of beam time structure will be critical to understanding backgrounds. The proposed Mu2e experiment will utilize {approx}200 ns (FW) bunches of 3 x 10{sup 7} protons at 8 GeV with a bunch-to-bunch period of 1695 ns. The out-of-bunch beam must be suppressed by a factor of 10{sup -10} relative to in-bunch beam and continuously monitored. I propose a Cerenkov-based particle telescope to measure secondary production from beam interactions in a several tens of microns thick foil. Correlating timing information with beam passage will allow the determination of relative beam intensity to arbitrary precision given a sufficiently long integration time. The goal is to verify out-of-bunch extinction to the level 10{sup -6} in the span of several seconds. This will allow near real-time monitoring of the initial extinction of the beam resonantly extracted from Fermilabs Debuncher before a system of AC dipoles and collimators, which will provide the final extinction. The effect on beam emittance is minimal, allowing the necessary continuous measurement. I will present the detector design and some concerns about bunch growth during the resonant extraction.

  8. Beam Loss Monitors for NSLS-II Storage Ring

    SciTech Connect

    Kramer, S.L.; Cameron, P.

    2011-03-28

    The shielding for the NSLS-II storage ring will provide adequate protection for the full injected beam losses in two cells of the ring around the injection point, but the remainder of the ring is shielded for lower losses of <10% top-off injection beam current. This will require a system to insure that beam losses do not exceed levels for a period of time that could cause excessive radiation exposure outside the shield walls. This beam Loss Control and Monitoring system will have beam loss monitors that will measure where the beam charge is lost around the ring, to warn operators if losses approach the design limits. To measure the charge loss quantitatively, we propose measuring the electron component of the shower as beam electrons hit the vacuum chamber (VC) wall. This will be done using the Cerenkov light as electrons transit ultra-pure fused silica rods placed close to the inner edge of the VC. The entire length of the rod will collect light from the electrons of the spread out shower resulting from the small glancing angle of the lost beam particles to the VC wall. The design and measurements results of the prototype Cerenkov BLM will be presented.

  9. Description and operation of the LEDA beam-position/intensity measurement module

    SciTech Connect

    Rose, C.R.; Stettler, M.W.

    1997-10-01

    This paper describes the specification, design and preliminary operation of the beam-position/intensity measurement module being built for the Low Energy Demonstration Accelerator (LEDA) and Accelerator Production of Tritium (APT) projects at Los Alamos National Laboratory. The module, based on the VXI footprint, is divided into three sections: first, the analog front-end which consists of logarithmic amplifiers, anti-alias filters, and digitizers; second, the digital-to-analog section for monitoring signals on the front panel; and third, the DSP, error correction, and VXI-interface section. Beam position is calculated based on the log-ratio transfer function. The module has four, 2-MHz, IF inputs suitable for two-axis position measurements. It has outputs in both digital and analog format for x- and y-position and beam intensity. Real-time error-correction is performed on the four input signals after they are digitized and before calculating the beam position to compensate for drift, offsets, gain non-linearities, and other systematic errors. This paper also describes how the on-line error-correction is implemented digitally and algorithmically.

  10. A non-invasive beam profile monitor for charged particle beams

    SciTech Connect

    Tzoganis, Vasilis; Welsch, Carsten P.

    2014-05-19

    Non-interceptive beam profile monitors are highly desirable in almost all particle accelerators. Such techniques are especially valuable in applications where real time monitoring of the beam properties is required while beam preservation and minimal influence on the vacuum are of the greatest importance. This applies to many kinds of accelerators such as high energy machines where the normal diagnostics cannot withstand the beam's power, medical machines where treatment time is valuable and cannot be allocated to diagnostics and also low energy, low intensity accelerators where the beam's properties are difficult to measure. This paper presents the design of a gas-jet based beam profile monitor which was developed and commissioned at the Cockcroft Institute and can operate in a very large background pressure range from 10{sup −7} down to below 10{sup −11} millibars. The functioning principle of the monitor is described and the first experimental results obtained using a 5 keV electron beam are discussed.

  11. Multipoint alignment monitoring with amorphous silicon position detectors in a complex light path

    NASA Astrophysics Data System (ADS)

    Alberdi, J.; Arce, P.; Barcala, J. M.; Calvo, E.; Ferrando, A.; Josa, M. I.; Molinero, A.; Navarrete, J.; Oller, J. C.; Yuste, C.; Calderón, A.; Gómez, G.; González-Sánchez, F. J.; Martínez-Rivero, C.; Matorras, F.; Rodrigo, T.; Ruiz-Árbol, P.; Sobrón, M.; Vila, I.; Virto, A. L.

    2010-12-01

    This document presents an application of the new generation of amorphous silicon position detecting (ASPD) sensors to multipoint alignment. Twelve units are monitored along a 20 m long laser beam, where the light path is deflected by 90° using a pentaprism.

  12. Pin diode calibration - beam overlap monitoring for low energy cooling

    SciTech Connect

    Drees, A.; Montag, C.; Thieberger, P.

    2015-09-30

    We were trying to address the question whether or not the Pin Diodes, currently installed approximately 1 meter downstream of the RHIC primary collimators, are suitable to monitor a recombination signal from the future RHIC low energy cooling section. A maximized recombination signal, with the Au+78 ions being lost on the collimator, will indicate optimal Au-electron beam overlap as well as velocity matching of the electron beam in the cooling section.

  13. High resolution, position sensitive detector for energetic particle beams

    NASA Astrophysics Data System (ADS)

    Marsh, E. P.; Strathman, M. D.; Reed, D. A.; Morse, D. H.; Pontau, A. E.; Odom, R. W.

    1993-05-01

    The performance and design of an imaging position sensitive, particle beam detector will be presented. The detector is minimally invasive, operates over a wide dynamic range (> 10 10), and exhibits high spatial resolution. The secondary electrons produced when a particle beam passes through a thin foil are imaged using stigmatic ion optics onto a two-dimensional imaging detector. Due to the low scattering cross section of the 6 nm carbon foil the detector is a minimal perturbation on the primary beam. A prototype detector with an image resolution of approximately 5 μm for a field of view of 1 mm has been reported [R.W. Odom, M.D. Strathman, S.E. Buttrill, Jr., and S.M. Bauman, Nucl. Instr. and Meth. B44 (1990) 465]. A higher resolution detector for imaging small beams (< 50 μm) with an image resolution of better than 0.5 μm has since been developed and its design is presented.

  14. Wide dynamic range beam profile monitor

    SciTech Connect

    Lee, D.M.; van Dyck, O.B.; Bilskie, J.R.; Brown, D.; Hardekopf, R.

    1985-10-01

    An economical harp multiplexer system has been developed to achieve a wide dynamic range. The harp system incorporates a pneumatically actuated harp detector with ceramic boards and carbon wires; a high-sensitivity multiplexer packaged in a double-wide NIM module; and flat, shielded ribbon cable consisting of individual twisted pairs. The system multiplexes 30 wires in each of the x and y planes simultaneously and operates with or without computer control. The system has operated in beams of 100 nA to 1 mA, 1- to 120-Hz repetition rate, with a signal-to-noise ratio of greater than 10/1.

  15. Wide dynamic range beam profile monitor

    SciTech Connect

    Lee, D.M.; Brown, D.; Hardekopf, R.; Bilskie, J.R.; van Dyck, O.B.V.

    1985-01-01

    An economical harp multiplexer system has been developed to achieve a wide dynamic range. The harp system incorporates a pneumatically actuated harp detector with ceramic boards and carbon wires; a high-sensitivity multiplexer packaged in a double-wide NIM module; and flat, shielded ribbon cable consisting of individual twisted pairs. The system multiplexes 30 wires in each of the x and y planes simultaneously and operates with or without computer control. The system has operated in beams of 100 nA to 1 mA, 1- to 120-Hz repetition rate, with a signal-to-noise ratio of greater than 10/1.

  16. Charged particle beam current monitoring tutorial

    SciTech Connect

    Webber, R.C.

    1994-10-01

    A tutorial presentation is made on topics related to the measurement of charged particle beam currents. The fundamental physics of electricity and magnetism pertinent to the problem is reviewed. The physics is presented with a stress on its interpretation from an electrical circuit theory point of view. The operation of devices including video pulse current transformers, direct current transformers, and gigahertz bandwidth wall current style transformers is described. Design examples are given for each of these types of devices. Sensitivity, frequency response, and physical environment are typical parameters which influence the design of these instruments in any particular application. Practical engineering considerations, potential pitfalls, and performance limitations are discussed.

  17. Characterization of a nondestructive beam profile monitor using luminescent emission

    NASA Astrophysics Data System (ADS)

    Variola, A.; Jung, R.; Ferioli, G.

    2007-12-01

    The LHC (large hadron collider) [LHC study group: LHC. The large hadron collider conceptual design; CERN/AC/95-05] is the future p-p collider under construction at CERN, Geneva. Over a circumference of 26.7 km a set of cryogenic dipoles and rf cavities will store and accelerate proton and ion beams up to energies of the order of 7 TeV. Injection in LHC will be performed by the CERN complex of accelerators, starting from the source and passing through the linac, the four booster rings, the proton synchrotron (PS), and super proton synchrotron (SPS) accelerators. One of the main constraints on LHC performance is emittance preservation along the whole chain of CERN accelerators. The accepted relative normalized emittance blowup after filamentation is ±7%. To monitor the beam and the emittance blowup process, a study of different prototypes of nonintercepting beam profile monitors has been performed. In this context a monitor using the luminescent emission of gases excited by ultrarelativistic protons (450 GeV) was developed and tested in the SPS ring. The results of beam size measurements and their evolution as a function of the machine parameters are presented. The image quality and resolution attainable in the LHC case have been assessed. A first full characterization of the luminescence cross section, spectrum, decay time, and afterglow effect for an ultrarelativistic proton beam is provided. Some significant results are also provided for lead ion beams.

  18. Monitoring system experiments on beam loss at SSRF injector

    NASA Astrophysics Data System (ADS)

    Cai, Jun; Xia, XiaoBin; Xu, XunJiang; Liu, Xin; Xu, JiaQiang; Wang, GuangHong; Zeng, Ming

    2011-12-01

    Experiments on beam loss by using beam loss monitoring (BLM) system were carried out at Shanghai Synchrotron Radiation Facility (SSRF) injector. This system used highly sensitive and current-integrated Si-photodiode detectors and an Ethernet data acquisition (DAQ) system. The experimental results demonstrate that the Si-photodiode detectors are a useful tool that provides dynamic information on beam loss and investigates problems of machine operation. It also shows that the Si-photodiode BLM system is suitable for pulse-radiation of high-energy accelerators.

  19. Beam position feedback system for the Advanced Photon Source

    SciTech Connect

    Chung, Y.

    1993-11-01

    The Advanced Photon Source (APS) will implement both global and local beam position feedback systems to stabilize the particle and X-ray beams for the storage ring. The systems consist of 20 VME crates distributed around the ring, each running multiple digital signal processors (DSP) running at 4kHz sampling rate with a proportional, integral, and derivative (PID) control algorithm. The particle and X-ray beam position data is shared by the distributed processors through networked reflective memory. A theory of closed orbit correction using the technique of singular value decomposition (SVD) of the response matrix and simulation of its application to the APS storage ring will be discussed. This technique combines the global and local feedback systems and resolves the conflict among multiple local feedback systems due to local bump closure error. Maximum correction efficiency is achieved by feeding back the global orbit data to the local feedback systems. The effect of the eddy current induced in the relatively thick (1/2 inch) vacuum chamber by the AC corrector magnet field for local feedback systems is compensated by digital filters. Results of experiments conducted on the X-ray ring of the National Synchrotron Light Source and the SPEAR at Stanford Synchrotron Radiation Laboratory will also be presented.

  20. Comment on ‘Proton beam monitor chamber calibration’

    NASA Astrophysics Data System (ADS)

    Palmans, Hugo; Vatnitsky, Stanislav M.

    2016-09-01

    We comment on a recent article (Gomà et al 2014 Phys. Med. Biol. 59 4961-71) which compares different routes of reference dosimetry for the energy dependent beam monitor calibration in scanned proton beams. In this article, a 3% discrepancy is reported between a Faraday cup and a plane-parallel ionization chamber in the experimental determination of the number of protons per monitor unit. It is further claimed that similar discrepancies between calorimetry and ionization chamber based dosimetry indicate that {{k}Q} -values tabulated for proton beams in IAEA TRS-398 might be overestimated. In this commentary we show, however, that this supporting argument misrepresents the evidence in the literature and that the results presented, together with published data, rather confirm that there exist unresolved problems with Faraday cup dosimetry. We also show that the comparison in terms of the number of protons gives a biased view on the uncertainty estimates for both detectors while the quantity of interest is absorbed dose to water or dose-area-product to water, even if a beam monitor is calibrated in terms of the number of protons. Gomà et al (2014 Phys. Med. Biol. 59 4961-71) also report on the discrepancy between cylindrical and plane-parallel ionization chambers and confirm experimentally that in the presence of a depth dose gradient, theoretical values of the effective point of measurement, or alternatively a gradient correction factor, account for the discrepancy. We believe this does not point to an error or shortcoming of IAEA TRS-398, which prescribes taking the centre of cylindrical ionization chambers as reference point, since it recommends reference dosimetry to be performed in the absence of a depth dose gradient. But these observations reveal that important aspects of beam monitor calibration in scanned proton beams are not addressed in IAEA TRS-398 given that those types of beams were not widely implemented at the time of its publication.

  1. Comment on ‘Proton beam monitor chamber calibration’

    NASA Astrophysics Data System (ADS)

    Palmans, Hugo; Vatnitsky, Stanislav M.

    2016-09-01

    We comment on a recent article (Gomà et al 2014 Phys. Med. Biol. 59 4961–71) which compares different routes of reference dosimetry for the energy dependent beam monitor calibration in scanned proton beams. In this article, a 3% discrepancy is reported between a Faraday cup and a plane-parallel ionization chamber in the experimental determination of the number of protons per monitor unit. It is further claimed that similar discrepancies between calorimetry and ionization chamber based dosimetry indicate that {{k}Q} -values tabulated for proton beams in IAEA TRS-398 might be overestimated. In this commentary we show, however, that this supporting argument misrepresents the evidence in the literature and that the results presented, together with published data, rather confirm that there exist unresolved problems with Faraday cup dosimetry. We also show that the comparison in terms of the number of protons gives a biased view on the uncertainty estimates for both detectors while the quantity of interest is absorbed dose to water or dose-area-product to water, even if a beam monitor is calibrated in terms of the number of protons. Gomà et al (2014 Phys. Med. Biol. 59 4961–71) also report on the discrepancy between cylindrical and plane-parallel ionization chambers and confirm experimentally that in the presence of a depth dose gradient, theoretical values of the effective point of measurement, or alternatively a gradient correction factor, account for the discrepancy. We believe this does not point to an error or shortcoming of IAEA TRS-398, which prescribes taking the centre of cylindrical ionization chambers as reference point, since it recommends reference dosimetry to be performed in the absence of a depth dose gradient. But these observations reveal that important aspects of beam monitor calibration in scanned proton beams are not addressed in IAEA TRS-398 given that those types of beams were not widely implemented at the time of its publication.

  2. Apparatus for monitoring X-ray beam alignment

    DOEpatents

    Steinmeyer, P.A.

    1991-10-08

    A self-contained, hand-held apparatus is provided for monitoring alignment of an X-ray beam in an instrument employing an X-ray source. The apparatus includes a transducer assembly containing a photoresistor for providing a range of electrical signals responsive to a range of X-ray beam intensities from the X-ray beam being aligned. A circuit, powered by a 7.5 VDC power supply and containing an audio frequency pulse generator whose frequency varies with the resistance of the photoresistor, is provided for generating a range of audible sounds. A portion of the audible range corresponds to low X-ray beam intensity. Another portion of the audible range corresponds to high X-ray beam intensity. The transducer assembly may include an a photoresistor, a thin layer of X-ray fluorescent material, and a filter layer transparent to X-rays but opaque to visible light. X-rays from the beam undergoing alignment penetrate the filter layer and excite the layer of fluorescent material. The light emitted from the fluorescent material alters the resistance of the photoresistor which is in the electrical circuit including the audio pulse generator and a speaker. In employing the apparatus, the X-ray beam is aligned to a complete alignment by adjusting the X-ray beam to produce an audible sound of the maximum frequency. 2 figures.

  3. TFTR neutral beam control and monitoring for DT operations

    SciTech Connect

    O`Connor, T.; Kamperschroer, J.; Chu, J.

    1995-12-31

    Record fusion power output has recently been obtained in TFTR with the injection of deuterium and tritium neutral beams. This significant achievement was due in part to the controls, software, and data processing capabilities added to the neutral beam system for DT operations. Chief among these improvements was the addition of SUN workstations and large dynamic data storage to the existing Central Instrumentation Control and Data Acquisition (CICADA) system. Essentially instantaneous look back over the recent shot history has been provided for most beam waveforms and analysis results. Gas regulation controls allowing remote switchover between deuterium and tritium were also added. With these tools, comparison of the waveforms and data of deuterium and tritium for four test conditioning pulses quickly produced reliable tritium setpoints. Thereafter, all beam conditioning was performed with deuterium, thus saving the tritium supply for the important DT injection shots. The lookback capability also led to modifications of the gas system to improve reliability and to control ceramic valve leakage by backbiasing. Other features added to improve the reliability and availability of DT neutral beam operations included master beamline controls and displays, a beamline thermocouple interlock system, a peak thermocouple display, automatic gas inventory and cryo panel gas loading monitoring, beam notching controls, a display of beam/plasma interlocks, and a feedback system to control beam power based on plasma conditions.

  4. A high resolution, single bunch, beam profile monitor

    SciTech Connect

    Norem, J.

    1992-08-26

    Efficient linear colliders require very small beam spots to produce high luminosities with reasonable input power, which limits the number of electrons which can be accelerated to high energies. The small beams, in turn, require high precision and stability in all accelerator components. Producing, monitoring and maintaining beams of the required quality has been, and will continue to be, difficult. A beam monitoring system which could be used to measure beam profile, size and stability at the final focus of a beamline or collider has been developed and is described here. The system uses nonimaging bremsstrahlung optics. The immediate use for this system would be examining the final focus spot at the SLAC/FFTB. The primary alternatives to this technique are those proposed by P. Chen / J. Buon, which analyses the energy and angular distributions of ion recoils to determine the aspect ratio of the electron bunch, and a method proposed by Shintake, which measures intensity variation of compton backscattered photons as the beam is moved across a pattern of standing waves produced by a laser.

  5. New Beam Loss Monitor for 12 GeV Upgrade

    SciTech Connect

    Jianxun Yan, Kelly Mahoney

    2009-10-01

    This paper describes a new VME based machine protection Beam Loss Monitor (BLM) signal processing board designed at Jefferson Lab to replace the current CAMAC based BLM board. The new eight-channel BLM signal processor has linear, logarithmic, and integrating amplifiers that simultaneously provide the optimal signal processing for each application. Amplified signals are digitized and then further processed through a Field Programmable Gate Array (FPGA). Combining both the diagnostic and machine protection functions in each channel allows the operator to tune-up and monitor beam operations while the machine protection is integrating the same signal. Other features include extensive built-in-self-test, fast shutdown interface (FSD), and 16-Mbit buffers for beam loss transient play-back. The new VME BLM board features high sensitivity, high resolution, and low cost per channel.

  6. Residual-gas-ionization beam profile monitors in RHIC

    SciTech Connect

    Connolly, R.; Fite, J.; Jao, S.; Trabocchi, C.

    2010-05-02

    Four ionization profile monitors (IPMs) are in RHIC to measure vertical and horizontal beam profiles in the two rings. These work by measuring the distribution of electrons produced by beam ionization of residual gas. During the last two years both the collection accuracy and signal/noise ratio have been improved. An electron source is mounted across the beam pipe from the collector to monitor microchannel plate (MCP) aging and the signal electrons are gated to reduce MCP aging and to allow charge replenishment between single-turn measurements. Software changes permit simultaneous measurements of any number of individual bunches in the ring. This has been used to measure emittance growth rates on six bunches of varying intensities in a single store. Also the software supports FFT analysis of turn-by-turn profiles of a single bunch at injection to detect dipole and quadrupole oscillations.

  7. A laser-wire beam-energy and beam-profile monitor at the BNL linac

    SciTech Connect

    Connolly, R.; Degen, C.; DeSanto, L.; Meng, W.; Michnoff, R.; Minty, M.; Nayak, S.

    2011-03-28

    In 2009 a beam-energy monitor was installed in the high energy beam transport (HEBT) line at the Brookhaven National Lab linac. This device measures the energies of electrons stripped from the 40mA H{sup -} beam by background gas. Electrons are stripped by the 2.0x10{sup -7}torr residual gas at a rate of {approx}1.5x10{sup -8}/cm. Since beam electrons have the same velocities as beam protons, the beam proton energy is deduced by multiplying the electron energy by m{sub p}/m{sub e}=1836. A 183.6MeV H{sup -} beam produces 100keV electrons. In 2010 we installed an optics plates containing a laser and scanning optics to add beam-profile measurement capability via photodetachment. Our 100mJ/pulse, Q-switched laser neutralizes 70% of the beam during its 10ns pulse. This paper describes the upgrades to the detector and gives profile and energy measurements.

  8. Application of Pixel-cell Detector Technology for Advanced Neutron Beam Monitors

    SciTech Connect

    Kopp, Daniel M.

    2011-01-11

    Application of Pixel-Cell Detector Technology for Advanced Neutron Beam Monitors Specifications of currently available neutron beam detectors limit their usefulness at intense neutron beams of large-scale national user facilities used for the advanced study of materials. A large number of neutron-scattering experiments require beam monitors to operate in an intense neutron beam flux of >10E+7 neutrons per second per square centimeter. For instance, a 4 cm x 4 cm intense beam flux of 6.25 x 10E+7 n/s/cm2 at the Spallation Neutron Source will put a flux of 1.00 x 10E+9 n/s at the beam monitor. Currently available beam monitors with a typical efficiency of 1 x 10E-4 will need to be replaced in less than two years of operation due to wire and gas degradation issues. There is also a need at some instruments for beam position information that are beyond the capabilities of currently available He-3 and BF3 neutron beam monitors. ORDELA, Inc.’s research under USDOE SBIR Grant (DE-FG02-07ER84844) studied the feasibility of using pixel-cell technology for developing a new generation of stable, long-life neutron beam monitors. The research effort has led to the development and commercialization of advanced neutron beam detectors that will directly benefit the Spallation Neutron Source and other intense neutron sources such as the High Flux Isotope Reactor. A prototypical Pixel-Cell Neutron Beam Monitor was designed and constructed during this research effort. This prototype beam monitor was exposed to an intense neutron beam at the HFIR SNS HB-2 test beam site. Initial measurements on efficiency, uniformity across the detector, and position resolution yielded excellent results. The development and test results have provided the required data to initiate the fabrication and commercialization of this next generation of neutron-detector systems. ORDELA, Inc. has (1) identified low-cost design and fabrication strategies, (2) developed and built pixel-cell detectors and

  9. First Beam Measurements with the LHC Synchrotron Light Monitors

    SciTech Connect

    Lefevre, Thibaut; Bravin, Enrico; Burtin, Gerard; Guerrero, Ana; Jeff, Adam; Rabiller, Aurelie; Roncarolo, Federico; Fisher, Alan; /SLAC

    2012-07-13

    The continuous monitoring of the transverse sizes of the beams in the Large Hadron Collider (LHC) relies on the use of synchrotron radiation and intensified video cameras. Depending on the beam energy, different synchrotron light sources must be used. A dedicated superconducting undulator has been built for low beam energies (450 GeV to 1.5 TeV), while edge and centre radiation from a beam-separation dipole magnet are used respectively for intermediate and high energies (up to 7 TeV). The emitted visible photons are collected using a retractable mirror, which sends the light into an optical system adapted for acquisition using intensified CCD cameras. This paper presents the design of the imaging system, and compares the expected light intensity with measurements and the calculated spatial resolution with a cross calibration performed with the wire scanners. Upgrades and future plans are also discussed.

  10. New x-ray pink-beam profile monitor system for the SPring-8 beamline front-end.

    PubMed

    Takahashi, Sunao; Kudo, Togo; Sano, Mutsumi; Watanabe, Atsuo; Tajiri, Hiroo

    2016-08-01

    A new beam profile monitoring system for the small X-ray beam exiting from the SPring-8 front-end was developed and tested at BL13XU. This system is intended as a screen monitor and also as a position monitor even at beam currents of 100 mA by using photoluminescence of a chemical vapor deposition-grown diamond film. To cope with the challenge that the spatial distribution of the photoluminescence in the vertical direction is too flat to detect the beam centroid within a limited narrow aperture, a filter was installed that absorbs the fundamental harmonic concentrated in the beam center, which resulted in "de-flattening" of the vertical distribution. For the measurement, the filter crossed the photon beam vertically at high speed to withstand the intense heat flux of the undulator pink-beam. A transient thermal analysis, which can simulate the movement of the irradiation position with time, was conducted to determine the appropriate configuration and the required moving speed of the filter to avoid accidental melting. In a demonstration experiment, the vertically separated beam profile could be successfully observed for a 0.8 × 0.8 mm(2) beam shaped by an XY slit and with a fundamental energy of 18.48 keV. The vertical beam centroid could be detected with a resolution of less than 0.1 mm. PMID:27587104

  11. New x-ray pink-beam profile monitor system for the SPring-8 beamline front-end

    NASA Astrophysics Data System (ADS)

    Takahashi, Sunao; Kudo, Togo; Sano, Mutsumi; Watanabe, Atsuo; Tajiri, Hiroo

    2016-08-01

    A new beam profile monitoring system for the small X-ray beam exiting from the SPring-8 front-end was developed and tested at BL13XU. This system is intended as a screen monitor and also as a position monitor even at beam currents of 100 mA by using photoluminescence of a chemical vapor deposition-grown diamond film. To cope with the challenge that the spatial distribution of the photoluminescence in the vertical direction is too flat to detect the beam centroid within a limited narrow aperture, a filter was installed that absorbs the fundamental harmonic concentrated in the beam center, which resulted in "de-flattening" of the vertical distribution. For the measurement, the filter crossed the photon beam vertically at high speed to withstand the intense heat flux of the undulator pink-beam. A transient thermal analysis, which can simulate the movement of the irradiation position with time, was conducted to determine the appropriate configuration and the required moving speed of the filter to avoid accidental melting. In a demonstration experiment, the vertically separated beam profile could be successfully observed for a 0.8 × 0.8 mm2 beam shaped by an XY slit and with a fundamental energy of 18.48 keV. The vertical beam centroid could be detected with a resolution of less than 0.1 mm.

  12. Beam-phase monitoring with non-destructive pickup

    SciTech Connect

    Bogaty, J.; Clifft, B.E.

    1995-08-01

    An intensity and phase-sensitive capacitive pickup was installed at the entrance to the PII linac. This device is based on an extension of the design of the Beam Current Monitor developed as part of the ATLAS radiation safety system. The purpose of the pickup is to allow the arrival phase of the beam from the ECR source at the entrance to the PII linac to be set to a standard which reproduces previous tune conditions and establishes a standard. The new pickups and associated electronics demonstrated sensitivity well below 1 electrical nanoamp but can handle beam currents of many electrical microamps as well. In addition to phase information, beam current is also measured by the units thus providing a continuous, non-intercepting current readout as well. From the very first use of PII, we established a few {open_quotes}reference tunes{close_quotes} for the linac and scaled those tunes for any other beam desired. For such scaling to work properly, the velocity and phase of the beam from the ion source must be fixed and reproducible. In last year`s FWP the new ATLAS Master Oscillator System was described. The new system has the ability of easily adjusting the beam arrival phase at the entrance to each of the major sections of the facility - PII, Booster, ATLAS. Our present techniques for establishing the beam arrival phase at the entrance of each of the linac sections are cumbersome and, sometimes, intellectually challenging. The installation of these capacitative pickups at the entrance to each of the linac sections will make the determination and setting of the beam arrival phase direct, simple, and dynamic. This should dramatically shorten our setup time for {open_quotes}old-tune{close_quotes} configurations and increase useful operating hours. Permanent electronics for the PII entrance pickup is under construction.

  13. High-Precision Head Positioning Using Multiple Offset Beams

    NASA Astrophysics Data System (ADS)

    Mizukami, Makoto; Yoshizawa, Takashi; Sato, Isamu

    1993-11-01

    This paper describes a new tracking technique with a multiple beam mechanism that will lead to low profile optical disk storage units with faster access speeds. In this technique, data tracking involves selection among multiple beams with minute offsets. It can accommodate four-beam laser diodes while assuring twice the tracking accuracy and ten times the tracking bandwidth of conventional approaches. Its servo performance depends on the total distance between the two outermost beams in the beam series on the medium.

  14. Silicon detectors for monitoring neutron beams in n-TOF beamlines

    SciTech Connect

    Cosentino, L.; Pappalardo, A.; Piscopo, M.; Finocchiaro, P.; Musumarra, A.; Barbagallo, M.; Colonna, N.; Damone, L.

    2015-07-15

    During 2014, the second experimental area (EAR2) was completed at the n-TOF neutron beam facility at CERN (n-TOF indicates neutron beam measurements by means of time of flight technique). The neutrons are produced via spallation, by means of a high-intensity 20 GeV pulsed proton beam impinging on a thick target. The resulting neutron beam covers the energy range from thermal to several GeV. In this paper, we describe two beam diagnostic devices, both exploiting silicon detectors coupled with neutron converter foils containing {sup 6}Li. The first one is based on four silicon pads and allows monitoring of the neutron beam flux as a function of the neutron energy. The second one, in beam and based on position sensitive silicon detectors, is intended for the reconstruction of the beam profile, again as a function of the neutron energy. Several electronic setups have been explored in order to overcome the issues related to the gamma flash, namely, a huge pulse present at the start of each neutron bunch which may blind the detectors for some time. The two devices were characterized with radioactive sources and also tested at the n-TOF facility at CERN. The wide energy and intensity range they proved capable of sustaining made them attractive and suitable to be used in both EAR1 and EAR2 n-TOF experimental areas, where they became immediately operational.

  15. Optimized x/y scanning head for laser beam positioning

    NASA Astrophysics Data System (ADS)

    Muth, Michael

    1996-08-01

    As a fast two-axis deflection unit for laser beam positioning, an X/Y scanning head based on two galvanometric scanners with vertical crossed axes is a central component of different applications in industry, medicine and communications. Some of these are laser markers, stereolithography devices, scanning laser vibrometers, laser trimmers, laser cutting machines, infrared scanners, lead bonders, Q-switches, laser ophthalmoscope, robotic vision systems, range finders, image digitizers, and laser graphic projectors for entertainment. Velocity and accuracy of the X/Y scanning heads are very important for the performance of the devices in which they are used. Therefore the dynamic properties of the X/Y scanning head must be optimized. One important criterion is the mass moment of inertia of the second scanning mirror. It can be reduced by inclining the axis of the first galvanometric scanner. To solve these problems both computer tools for the optical and mechanical optimization, and measuring devices to minimize the wobble and jitter of galvanometric scanners were developed. The development of scanning heads for different apertures (laser beam diameters), scan angles and F-(Theta) -objectives was done for SCANLAB GmbH (Puchheim/Munchen, Germany), one of the three leading manufacturers for galvanometric scanners.

  16. Beam profile monitor for the NSLS vuv ring employing linear photodiode arrays

    SciTech Connect

    Nawrocky, R.J.; Galayda, J.; Yu, L.H.; Shu, D.M.

    1985-01-01

    Among the most important parameters of a storage accelerator are the position and size of the particle beam. In an electron machine, these parameters can be derived from measurements of the emitted synchrotron radiation. We discuss a system which monitors the two-dimensional profile of the synchrotron light in the NSLS vuv ring using commercially available high-resolution linear photosensitive diode arrays. The optical system has been designed to match the size of the image space to the dimensions of the diode sensor area. The scanning rate is automatically adjusted to hold the peaks of the profiles constant over a wide range of beam intensity variations. Video signals from the diode sensors can be readily interfaced to a computer for beam diagnostic purposes. Optics and factors determining the overall resolution of the system are discussed. Preliminary results of beam observations are presented.

  17. Broadband optical monitoring of filters fabricated using molecular beam deposition

    NASA Astrophysics Data System (ADS)

    Powell Fisher, Shari; Hale, Christopher C.; Muirhead, Ian T.; Mathew, John G. H.; Cornwell, Robert J.

    1990-08-01

    A broadband optical monitoring system to assist with the control of complex filter designs has been implemented on a newly installed Molecular Beam Deposition (MBD) facility which has been adapted for the growth of optical thin films. When depositing a multilayer structure like a Fabry- Perot etalon with very narrow features whose location depends upon a precise optical thickness the broadband optical monitor is an essential addition to process control. In addition to providing the capability to observe the growth of a sensitive optical feature the broadband optical monitor is used to calibrate other process control methods. This saves a considerable amount of processing time and demonstrates the cost effectiveness of such a system. By the judicious use of broadband optical monitoring a very high degree of control and efficiency is added to MBD processing of optical thin films. 1.

  18. RF Cavity Induced Sensitivity Limitations on Beam Loss Monitors

    NASA Astrophysics Data System (ADS)

    Kastriotou, M.; Degiovanni, A.; Sousa, F. S. Domingues; Effinger, E.; Holzer, E. B.; Quirante, J. L. Navarro; del Busto, E. N.; Tecker, F.; Viganò, W.; Welsch, C. P.; Woolley, B. J.

    Due to the secondary showers generated when a particle hits the vacuum chamber, beam losses at an accelerator may be detected via radiation detectors located near the beam line. Several sources of background can limit the sensitivity and reduce the dynamic range of a Beam Loss Monitor (BLM). This document concentrates on potential sources of background generated near high gradient RF cavities due to dark current and voltage breakdowns. An optical fibre has been installed at an experiment of the Compact Linear Collider (CLIC) Test Facility (CTF3), where a dedicated study of the performance of a loaded and unloaded CLIC accelerating structure is undergoing. An analysis of the collected data and a benchmarking simulation are presented to estimate BLM sensitivity limitations. Moreover, the feasibility for the use of BLMs optimised for the diagnostics of RF cavities is discussed.

  19. Absolute beam emittance measurements at RHIC using ionization profile monitors

    SciTech Connect

    Minty, M.; Connolly, R; Liu, C.; Summers, T.; Tepikian, S.

    2014-08-15

    In the past, comparisons between emittance measurements obtained using ionization profile monitors, Vernier scans (using as input the measured rates from the zero degree counters, or ZDCs), the polarimeters and the Schottky detectors evidenced significant variations of up to 100%. In this report we present studies of the RHIC ionization profile monitors (IPMs). After identifying and correcting for two systematic instrumental errors in the beam size measurements, we present experimental results showing that the remaining dominant error in beam emittance measurements at RHIC using the IPMs was imprecise knowledge of the local beta functions. After removal of the systematic errors and implementation of measured beta functions, precise emittance measurements result. Also, consistency between the emittances measured by the IPMs and those derived from the ZDCs was demonstrated.

  20. Method and apparatus to monitor a beam of ionizing radiation

    DOEpatents

    Blackburn, Brandon W.; Chichester, David L.; Watson, Scott M.; Johnson, James T.; Kinlaw, Mathew T.

    2015-06-02

    Methods and apparatus to capture images of fluorescence generated by ionizing radiation and determine a position of a beam of ionizing radiation generating the fluorescence from the captured images. In one embodiment, the fluorescence is the result of ionization and recombination of nitrogen in air.

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

    SciTech Connect

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

    2015-01-01

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

  2. A fast profile monitor with scintillating fiber hodoscopes for high-intensity photon beams

    NASA Astrophysics Data System (ADS)

    Ishikawa, T.; Fujimura, H.; Hamano, H.; Hashimoto, R.; Honda, Y.; Ishida, T.; Kaida, S.; Kanda, H.; Kido, S.; Matsumura, Y.; Miyabe, M.; Mizutani, K.; Nagasawa, I.; Nakamura, A.; Nanbu, K.; Nawa, K.; Ogushi, S.; Shibasaki, Y.; Shimizu, H.; Sugai, H.; Suzuki, K.; Takahashi, K.; Takahashi, S.; Taniguchi, Y.; Tokiyasu, A. O.; Tsuchikawa, Y.; Yamazaki, H.

    2016-03-01

    A fast beam-profile monitor has been developed for high-energy photon beamlines at the Research Center for Electron Photon Science, Tohoku University. The position of the photon converted into an electron-positron pair in a 0.5 mm-thick aluminum plate is measured with two hodoscopes made of scintillating fibers with cross-sections of 3 × 3mm2. Events in which charged particles are produced upstream are rejected with a charge veto plastic scintillator placed in front of the plate, and pair-production events are identified with a trigger plastic scintillator placed behind the plate. The position is determined by a developed logic module with a field-programmable gate array. The dead time for processing an event is 35 ns, and a high data acquisition efficiency (~ 100 %) can be achieved with this monitor for high-intensity photon beams corresponding to 20 MHz tagging signals.

  3. DATA ACQUISITION FOR SNS BEAM LOSS MONITOR SYSTEM

    SciTech Connect

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

    2003-10-13

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

  4. Prone position craniotomy in pregnancy without fetal heart rate monitoring.

    PubMed

    Jacob, Jean; Alexander, Ashish; Philip, Shoba; Thomas, Anoop

    2016-09-01

    A pregnant patient in second trimester scheduled for posterior fossa craniotomy in prone position is a challenge for the anesthesiologist. Things to consider are physiological changes during pregnancy, non-obstetric surgery in pregnant patients, neuroanesthetic principles, effects of prone positioning, and need for fetal heart rate (FHR) monitoring. We have described the anesthetic management of this case and discussed intra-operative FHR monitoring including controversies about its role, indications, and various options available as per fetal gestational age. In our case we attempted intermittent intra-operative FHR monitoring to optimize maternal positioning and fetal oxygenation even though the fetus was pre-viable. However the attempt was abandoned due to practical difficulties with prone positioning. Patient made good neurological recovery following the procedure and delivered a healthy term baby 4 months later. Decisions regarding fetal monitoring should be individualized based on viability of the fetus and feasibility of emergency cesarean delivery. Good communication between a multidisciplinary team involving neurosurgeon, anesthesiologist, obstetrician, and neonatologist is important for a successful outcome for mother and fetus. We conclude that prone position neurosurgery can safely be carried out in a pregnant patient with pre-viable fetus without FHR monitoring. PMID:27555144

  5. A real-time intercepting beam-profile monitor for a medical cyclotron

    SciTech Connect

    Hendriks, C.; Uittenbosch, T.; Cameron, D.; Kellogg, S.; Gray, D.; Buckley, K.; Schaffer, P.; Verzilov, V.; Hoehr, C.

    2013-11-15

    There is a lack of real-time continuous beam-diagnostic tools for medical cyclotrons due to high power deposition during proton irradiation. To overcome this limitation, we have developed a profile monitor that is capable of providing continuous feedback about beam shape and current in real time while it is inserted in the beam path. This enables users to optimize the beam profile and observe fluctuations in the beam over time with periodic insertion of the monitor.

  6. A real-time intercepting beam-profile monitor for a medical cyclotron.

    PubMed

    Hendriks, C; Uittenbosch, T; Cameron, D; Kellogg, S; Gray, D; Buckley, K; Schaffer, P; Verzilov, V; Hoehr, C

    2013-11-01

    There is a lack of real-time continuous beam-diagnostic tools for medical cyclotrons due to high power deposition during proton irradiation. To overcome this limitation, we have developed a profile monitor that is capable of providing continuous feedback about beam shape and current in real time while it is inserted in the beam path. This enables users to optimize the beam profile and observe fluctuations in the beam over time with periodic insertion of the monitor.

  7. A real-time intercepting beam-profile monitor for a medical cyclotron

    NASA Astrophysics Data System (ADS)

    Hendriks, C.; Uittenbosch, T.; Cameron, D.; Kellogg, S.; Gray, D.; Buckley, K.; Schaffer, P.; Verzilov, V.; Hoehr, C.

    2013-11-01

    There is a lack of real-time continuous beam-diagnostic tools for medical cyclotrons due to high power deposition during proton irradiation. To overcome this limitation, we have developed a profile monitor that is capable of providing continuous feedback about beam shape and current in real time while it is inserted in the beam path. This enables users to optimize the beam profile and observe fluctuations in the beam over time with periodic insertion of the monitor.

  8. Performance of MACACO Compton telescope for ion-beam therapy monitoring: first test with proton beams.

    PubMed

    Solevi, Paola; Muñoz, Enrique; Solaz, Carles; Trovato, Marco; Dendooven, Peter; Gillam, John E; Lacasta, Carlos; Oliver, Josep F; Rafecas, Magdalena; Torres-Espallardo, Irene; Llosá, Gabriela

    2016-07-21

    In order to exploit the advantages of ion-beam therapy in a clinical setting, delivery verification techniques are necessary to detect deviations from the planned treatment. Efforts are currently oriented towards the development of devices for real-time range monitoring. Among the different detector concepts proposed, Compton cameras are employed to detect prompt gammas and represent a valid candidate for real-time range verification. We present the first on-beam test of MACACO, a Compton telescope (multi-layer Compton camera) based on lanthanum bromide crystals and silicon photo-multipliers. The Compton telescope was first characterized through measurements and Monte Carlo simulations. The detector linearity was measured employing (22)Na and Am-Be sources, obtaining about 10% deviation from linearity at 3.44 MeV. A spectral image reconstruction algorithm was tested on synthetic data. Point-like sources emitting gamma rays with energy between 2 and 7 MeV were reconstructed with 3-5 mm resolution. The two-layer Compton telescope was employed to measure radiation emitted from a beam of 150 MeV protons impinging on a cylindrical PMMA target. Bragg-peak shifts were achieved via adjustment of the PMMA target location and the resulting measurements used during image reconstruction. Reconstructed Bragg peak profiles proved sufficient to observe peak-location differences within 10 mm demonstrating the potential of the MACACO Compton Telescope as a monitoring device for ion-beam therapy. PMID:27352107

  9. Performance of MACACO Compton telescope for ion-beam therapy monitoring: first test with proton beams

    NASA Astrophysics Data System (ADS)

    Solevi, Paola; Muñoz, Enrique; Solaz, Carles; Trovato, Marco; Dendooven, Peter; Gillam, John E.; Lacasta, Carlos; Oliver, Josep F.; Rafecas, Magdalena; Torres-Espallardo, Irene; Llosá, Gabriela

    2016-07-01

    In order to exploit the advantages of ion-beam therapy in a clinical setting, delivery verification techniques are necessary to detect deviations from the planned treatment. Efforts are currently oriented towards the development of devices for real-time range monitoring. Among the different detector concepts proposed, Compton cameras are employed to detect prompt gammas and represent a valid candidate for real-time range verification. We present the first on-beam test of MACACO, a Compton telescope (multi-layer Compton camera) based on lanthanum bromide crystals and silicon photo-multipliers. The Compton telescope was first characterized through measurements and Monte Carlo simulations. The detector linearity was measured employing 22Na and Am-Be sources, obtaining about 10% deviation from linearity at 3.44 MeV. A spectral image reconstruction algorithm was tested on synthetic data. Point-like sources emitting gamma rays with energy between 2 and 7 MeV were reconstructed with 3-5 mm resolution. The two-layer Compton telescope was employed to measure radiation emitted from a beam of 150 MeV protons impinging on a cylindrical PMMA target. Bragg-peak shifts were achieved via adjustment of the PMMA target location and the resulting measurements used during image reconstruction. Reconstructed Bragg peak profiles proved sufficient to observe peak-location differences within 10 mm demonstrating the potential of the MACACO Compton Telescope as a monitoring device for ion-beam therapy.

  10. Performance of MACACO Compton telescope for ion-beam therapy monitoring: first test with proton beams

    NASA Astrophysics Data System (ADS)

    Solevi, Paola; Muñoz, Enrique; Solaz, Carles; Trovato, Marco; Dendooven, Peter; Gillam, John E.; Lacasta, Carlos; Oliver, Josep F.; Rafecas, Magdalena; Torres-Espallardo, Irene; Llosá, Gabriela

    2016-07-01

    In order to exploit the advantages of ion-beam therapy in a clinical setting, delivery verification techniques are necessary to detect deviations from the planned treatment. Efforts are currently oriented towards the development of devices for real-time range monitoring. Among the different detector concepts proposed, Compton cameras are employed to detect prompt gammas and represent a valid candidate for real-time range verification. We present the first on-beam test of MACACO, a Compton telescope (multi-layer Compton camera) based on lanthanum bromide crystals and silicon photo-multipliers. The Compton telescope was first characterized through measurements and Monte Carlo simulations. The detector linearity was measured employing 22Na and Am-Be sources, obtaining about 10% deviation from linearity at 3.44 MeV. A spectral image reconstruction algorithm was tested on synthetic data. Point-like sources emitting gamma rays with energy between 2 and 7 MeV were reconstructed with 3–5 mm resolution. The two-layer Compton telescope was employed to measure radiation emitted from a beam of 150 MeV protons impinging on a cylindrical PMMA target. Bragg-peak shifts were achieved via adjustment of the PMMA target location and the resulting measurements used during image reconstruction. Reconstructed Bragg peak profiles proved sufficient to observe peak-location differences within 10 mm demonstrating the potential of the MACACO Compton Telescope as a monitoring device for ion-beam therapy.

  11. Performance of MACACO Compton telescope for ion-beam therapy monitoring: first test with proton beams.

    PubMed

    Solevi, Paola; Muñoz, Enrique; Solaz, Carles; Trovato, Marco; Dendooven, Peter; Gillam, John E; Lacasta, Carlos; Oliver, Josep F; Rafecas, Magdalena; Torres-Espallardo, Irene; Llosá, Gabriela

    2016-07-21

    In order to exploit the advantages of ion-beam therapy in a clinical setting, delivery verification techniques are necessary to detect deviations from the planned treatment. Efforts are currently oriented towards the development of devices for real-time range monitoring. Among the different detector concepts proposed, Compton cameras are employed to detect prompt gammas and represent a valid candidate for real-time range verification. We present the first on-beam test of MACACO, a Compton telescope (multi-layer Compton camera) based on lanthanum bromide crystals and silicon photo-multipliers. The Compton telescope was first characterized through measurements and Monte Carlo simulations. The detector linearity was measured employing (22)Na and Am-Be sources, obtaining about 10% deviation from linearity at 3.44 MeV. A spectral image reconstruction algorithm was tested on synthetic data. Point-like sources emitting gamma rays with energy between 2 and 7 MeV were reconstructed with 3-5 mm resolution. The two-layer Compton telescope was employed to measure radiation emitted from a beam of 150 MeV protons impinging on a cylindrical PMMA target. Bragg-peak shifts were achieved via adjustment of the PMMA target location and the resulting measurements used during image reconstruction. Reconstructed Bragg peak profiles proved sufficient to observe peak-location differences within 10 mm demonstrating the potential of the MACACO Compton Telescope as a monitoring device for ion-beam therapy.

  12. Rocket-borne positive and neutral beam experimental plan

    NASA Astrophysics Data System (ADS)

    Carpenter, J. W.; Humphrey, C. H.

    1983-01-01

    In this report the design of a rocket-borne charge ejection payload consisting of proton and neutral hydrogen beams is presented. The experimental plan calls for beams to be emitted up, down, and perpendicular to the geomagnetic field to be intercepted by throw-away detectors (TADS). This experimental plan is designed to be very cost effective, while extending the present upper limit of heavy charged beams to higher levels and revealing significant scientific information.

  13. Non-invasive monitoring of therapeutic carbon ion beams in a homogeneous phantom by tracking of secondary ions.

    PubMed

    Gwosch, K; Hartmann, B; Jakubek, J; Granja, C; Soukup, P; Jäkel, O; Martišíková, M

    2013-06-01

    Radiotherapy with narrow scanned carbon ion beams enables a highly accurate treatment of tumours while sparing the surrounding healthy tissue. Changes in the patient's geometry can alter the actual ion range in tissue and result in unfavourable changes in the dose distribution. Consequently, it is desired to verify the actual beam delivery within the patient. Real-time and non-invasive measurement methods are preferable. Currently, the only technically feasible method to monitor the delivered dose distribution within the patient is based on tissue activation measurements by means of positron emission tomography (PET). An alternative monitoring method based on tracking of prompt secondary ions leaving a patient irradiated with carbon ion beams has been previously suggested. It is expected to help in overcoming the limitations of the PET-based technique like physiological washout of the beam induced activity, low signal and to allow for real-time measurements. In this paper, measurements of secondary charged particle tracks around a head-sized homogeneous PMMA phantom irradiated with pencil-like carbon ion beams are presented. The investigated energies and beam widths are within the therapeutically used range. The aim of the study is to deduce properties of the primary beam from the distribution of the secondary charged particles. Experiments were performed at the Heidelberg Ion Beam Therapy Center, Germany. The directions of secondary charged particles emerging from the PMMA phantom were measured using an arrangement of two parallel pixelated silicon detectors (Timepix). The distribution of the registered particle tracks was analysed to deduce its dependence on clinically important beam parameters: beam range, width and position. Distinct dependencies of the secondary particle tracks on the properties of the primary carbon ion beam were observed. In the particular experimental set-up used, beam range differences of 1.3 mm were detectable. In addition, variations in

  14. Non-invasive monitoring of therapeutic carbon ion beams in a homogeneous phantom by tracking of secondary ions.

    PubMed

    Gwosch, K; Hartmann, B; Jakubek, J; Granja, C; Soukup, P; Jäkel, O; Martišíková, M

    2013-06-01

    Radiotherapy with narrow scanned carbon ion beams enables a highly accurate treatment of tumours while sparing the surrounding healthy tissue. Changes in the patient's geometry can alter the actual ion range in tissue and result in unfavourable changes in the dose distribution. Consequently, it is desired to verify the actual beam delivery within the patient. Real-time and non-invasive measurement methods are preferable. Currently, the only technically feasible method to monitor the delivered dose distribution within the patient is based on tissue activation measurements by means of positron emission tomography (PET). An alternative monitoring method based on tracking of prompt secondary ions leaving a patient irradiated with carbon ion beams has been previously suggested. It is expected to help in overcoming the limitations of the PET-based technique like physiological washout of the beam induced activity, low signal and to allow for real-time measurements. In this paper, measurements of secondary charged particle tracks around a head-sized homogeneous PMMA phantom irradiated with pencil-like carbon ion beams are presented. The investigated energies and beam widths are within the therapeutically used range. The aim of the study is to deduce properties of the primary beam from the distribution of the secondary charged particles. Experiments were performed at the Heidelberg Ion Beam Therapy Center, Germany. The directions of secondary charged particles emerging from the PMMA phantom were measured using an arrangement of two parallel pixelated silicon detectors (Timepix). The distribution of the registered particle tracks was analysed to deduce its dependence on clinically important beam parameters: beam range, width and position. Distinct dependencies of the secondary particle tracks on the properties of the primary carbon ion beam were observed. In the particular experimental set-up used, beam range differences of 1.3 mm were detectable. In addition, variations in

  15. Summary of the 2014 Beam-Halo Monitoring Workshop

    SciTech Connect

    Fisher, Alan

    2015-09-25

    Understanding and controlling beam halo is important for high-intensity hadron accelerators, for high-brightness electron linacs, and for low-emittance light sources. This can only be achieved by developing suitable diagnostics. The main challenge faced by such instrumentation is the high dynamic range needed to observe the halo in the presence of an intense core. In addition, measurements must often be made non-invasively. This talk summarizes the one-day workshop on Beam-Halo Monitoring that was held at SLAC on September 19 last year, immediately following IBIC 2014 in Monterey. Workshop presentations described invasive techniques using wires, screens, or crystal collimators, and non-invasive measurements with gas or scattered electrons. Talks on optical methods showed the close links between observing halo and astronomical problems like observing the solar corona or directly observing a planet orbiting another star.

  16. Quantitative experiments with electrons in a positively charged beam

    SciTech Connect

    Molvik, A W; Vay, J; Covo, M K; Cohen, R; Baca, D; Bieniosek, F; Friedman, A; Leister, C; Lund, S M; Seidl, P; Sharp, W

    2006-12-06

    Intense ion beams are difficult to maintain as non-neutral plasmas. Experiments and simulations are used to study the complex interactions between beam ions and (unwanted) electrons. Such ''electron clouds'' limit the performance of many accelerators. To characterize electron clouds, a number of parameters are measured including: total and local electron production and loss for each of three major sources, beam potential versus time, electron line-charge density, and gas pressure within the beam. Electron control methods include surface treatments to reduce electron and gas emission, and techniques to remove electrons from the beam, or block their capture by the beam. Detailed, self-consistent simulations include beam-transport fields, and electron and gas generation and transport; these compute unexpectedly rich behavior, much of which is confirmed experimentally. For example, in a quadrupole magnetic field, ion and dense electron plasmas interact to produce multi-kV oscillations in the electron plasma and distortions of the beam velocity space distribution, without the system becoming homogeneous or locally neutral.

  17. A real-time beam-profile monitor for a PET cyclotron

    NASA Astrophysics Data System (ADS)

    Hoehr, C.; Uittenbosch, T.; Verzilov, V.; English, W.; Buckley, K.; Gray, D.; Kellog, S.; Cameron, D.; Schaffer, P.

    2012-12-01

    Beam profiles in medical cyclotrons are traditionally measured using techniques that do not provide any information about short-term fluctuations of the beam shape or beam intensity. To overcome this, we have developed a real-time harp beam profile monitor which can withstand beam power in excess of 300 W. The monitor and electronics were constructed and applied toward a 13 MeV proton beam with current of up to 25 μA. Herein are reported preliminary beam-profile measurement results.

  18. A real-time beam-profile monitor for a PET cyclotron

    SciTech Connect

    Hoehr, C.; Uittenbosch, T.; Verzilov, V.; English, W.; Buckley, K.; Gray, D.; Kellog, S.; Cameron, D.; Schaffer, P.

    2012-12-19

    Beam profiles in medical cyclotrons are traditionally measured using techniques that do not provide any information about short-term fluctuations of the beam shape or beam intensity. To overcome this, we have developed a real-time harp beam profile monitor which can withstand beam power in excess of 300 W. The monitor and electronics were constructed and applied toward a 13 MeV proton beam with current of up to 25 {mu}A. Herein are reported preliminary beam-profile measurement results.

  19. Quantitative Experiments With Electrons in a Positively Charged Beam

    SciTech Connect

    Molvik, A W; Vay, J; Covo, M K; Cohen, R; Baca, D; Bieniosek, F; Friedman, A; Leister, C; Lund, S M; Seidl, P; Sharp, W

    2006-10-27

    Intense ion beams are an extreme example of, and difficult to maintain as, a non-neutral plasma. Experiments and simulations are used to study the complex interactions between beam ions and (unwanted) electrons. Such ''electron clouds'' limit the performance of many accelerators. To characterize electron clouds, a number of parameters are measured including: total and local electron production and loss for each of three major sources, beam potential versus time, electron line-charge density, and gas pressure within the beam. Electron control methods include surface treatments to reduce electron and gas emission, and techniques to remove, or block, electrons from the beam. Detailed, self-consistent simulations include beam-transport fields, and electron and gas generation and consistent transport, to compute unexpectedly rich behavior, much of which is confirmed experimentally. For example, in a quadrupole magnetic field, ion and dense electron plasmas interact to produce multi-kV oscillations in the electron plasma and distortions of the beam velocity space distribution, without becoming homogenous or locally neutral.

  20. Apparatus for precision focussing and positioning of a beam waist on a target

    NASA Technical Reports Server (NTRS)

    Lynch, Dana H. (Inventor); Gunter, William D. (Inventor); Mcalister, Kenneth W. (Inventor)

    1991-01-01

    The invention relates to optical focussing apparatus and, more particularly, to optical apparatus for focussing a highly collimated Gaussian beam which provides independent and fine control over the focus waist diameter, the focus position both along the beam axis and transverse to the beam, and the focus angle. A beam focussing and positioning apparatus provides focussing and positioning for the waist of a waisted beam at a desired location on a target such as an optical fiber. The apparatus includes a first lens, having a focal plane f sub 1, disposed in the path of an incoming beam and a second lens, having a focal plane f sub 2 and being spaced downstream from the first lens by a distance at least equal to f sub 1 + 10 f sub 2, which cooperates with the first lens to focus the waist of the beam on the target. A rotatable optical device, disposed upstream of the first lens, adjusts the angular orientation of the beam waist. The transverse position of the first lens relative to the axis of the beam is varied to control the transverse position of the beam waist relative to the target (a fiber optic as shown) while the relative axial positions of the lenses are varied to control the diameter of the beam waist and to control the axial position of the beam waist. Mechanical controllers C sub 1, C sub 2, C sub 3, C sub 4, and C sub 5 control the elements of the optical system. How seven adjustments can be made to correctly couple a laser beam into an optical fiber is illustrated. Prior art systems employing optical techniques to couple a laser beam into an optical fiber or other target simply do not provide the seven necessary adjustments. The closest known prior art, a Newport coupler, provides only two of the seven required adjustments.

  1. GEM-based thermal neutron beam monitors for spallation sources

    NASA Astrophysics Data System (ADS)

    Croci, G.; Claps, G.; Caniello, R.; Cazzaniga, C.; Grosso, G.; Murtas, F.; Tardocchi, M.; Vassallo, E.; Gorini, G.; Horstmann, C.; Kampmann, R.; Nowak, G.; Stoermer, M.

    2013-12-01

    The development of new large area and high flux thermal neutron detectors for future neutron spallation sources, like the European Spallation Source (ESS) is motivated by the problem of 3He shortage. In the framework of the development of ESS, GEM (Gas Electron Multiplier) is one of the detector technologies that are being explored as thermal neutron sensors. A first prototype of GEM-based thermal neutron beam monitor (bGEM) has been built during 2012. The bGEM is a triple GEM gaseous detector equipped with an aluminum cathode coated by 1 μm thick B4C layer used to convert thermal neutrons to charged particles through the 10B(n,7Li)α nuclear reaction. This paper describes the results obtained by testing a bGEM detector at the ISIS spallation source on the VESUVIO beamline. Beam profiles (FWHMx=31 mm and FWHMy=36 mm), bGEM thermal neutron counting efficiency (≈1%), detector stability (3.45%) and the time-of-flight spectrum of the beam were successfully measured. This prototype represents the first step towards the development of thermal neutrons detectors with efficiency larger than 50% as alternatives to 3He-based gaseous detectors.

  2. The LCLS Undulator Beam Loss Monitor Readout System

    SciTech Connect

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

    2012-07-23

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

  3. Apparatus and method for monitoring the intensities of charged particle beams

    DOEpatents

    Varma, Matesh N.; Baum, John W.

    1982-11-02

    Charged particle beam monitoring means (40) are disposed in the path of a charged particle beam (44) in an experimental device (10). The monitoring means comprise a beam monitoring component (42) which is operable to prevent passage of a portion of beam (44), while concomitantly permitting passage of another portion thereof (46) for incidence in an experimental chamber (18), and providing a signal (I.sub.m) indicative of the intensity of the beam portion which is not passed. Calibration means (36) are disposed in the experimental chamber in the path of the said another beam portion and are operable to provide a signal (I.sub.f) indicative of the intensity thereof. Means (41 and 43) are provided to determine the ratio (R) between said signals whereby, after suitable calibration, the calibration means may be removed from the experimental chamber and the intensity of the said another beam portion determined by monitoring of the monitoring means signal, per se.

  4. New and improved apparatus and method for monitoring the intensities of charged-particle beams

    DOEpatents

    Varma, M.N.; Baum, J.W.

    1981-01-16

    Charged particle beam monitoring means are disposed in the path of a charged particle beam in an experimental device. The monitoring means comprise a beam monitoring component which is operable to prevent passage of a portion of beam, while concomitantly permitting passage of another portion thereof for incidence in an experimental chamber, and providing a signal (I/sub m/) indicative of the intensity of the beam portion which is not passed. Caibration means are disposed in the experimental chamber in the path of the said another beam portion and are operable to provide a signal (I/sub f/) indicative of the intensity thereof. Means are provided to determine the ratio (R) between said signals whereby, after suitable calibration, the calibration means may be removed from the experimental chamber and the intensity of the said another beam portion determined by monitoring of the monitoring means signal, per se.

  5. Calculation of focal positions in an optical head using a four-beam laser diode

    NASA Astrophysics Data System (ADS)

    Shinoda, Masahisa; Kime, Kenjiro

    1998-10-01

    Calculation method for focal positions in a multi-beam optical head using a multi-beam laser diode is introduced. In this calculation model, focal positions were so calculated that a light source of each laser beam with a specific source height and an astigmatic difference was imaged by optical lenses and a beam shaping prism. Calculated results show that four focal positions are located each other with defocus along the optical axis due to the curvature of field of lenses. Astigmatic differences in focal spots caused by the laser diode characteristics can be decreased by almost zero with a displacement of a collimator lens along the optical axis.

  6. Tracking with head position using an electrooptical monitor

    NASA Technical Reports Server (NTRS)

    Chouet, B. A.; Young, L. R.

    1974-01-01

    An electrooptical head-position monitoring system was designed and built and is used in single-axis and three-axis 'hands-off' control tasks. The monitor consists of a transparent plexiglass body-fixed helmet provided with a set of eight silicon photodetectors sensing pitch, roll, and yaw motions of the head. Two light-emitting diodes, attached to the pilot's helmet liner, provide the ac modulated near infrared radiation. Head control is compared with conventional manual control for single-axis and three-axis tracking tasks. Both performance curves and describing functions are presented.

  7. Improved Oxygen-Beam Texturing of Glucose-Monitoring Optics

    NASA Technical Reports Server (NTRS)

    Banks, Bruce A.

    2006-01-01

    An improved method has been devised for using directed, hyperthermal beams of oxygen atoms and ions to impart desired textures to the tips of polymethylmethacrylate [PMMA] optical fibers to be used in monitoring the glucose content of blood. The improved method incorporates, but goes beyond, the method described in Texturing Blood-Glucose- Monitoring Optics Using Oxygen Beams (LEW-17642-1), NASA Tech Briefs, Vol. 29, No. 4 (April 2005), page 11a. The basic principle of operation of such a glucose-monitoring sensor is as follows: The textured surface of the optical fiber is coated with chemicals that interact with glucose in such a manner as to change the reflectance of the surface. Light is sent down the optical fiber and is reflected from, the textured surface. The resulting change in reflectance of the light is measured as an indication of the concentration of glucose. The required texture on the ends of the optical fibers is a landscape of microscopic cones or pillars having high aspect ratios (microscopic structures being taller than they are wide). The average distance between hills must be no more than about 5 mso that blood cells (which are wider) cannot enter the valleys between the hills, where they would interfere with optical sensing of glucose in the blood plasma. On the other hand, the plasma is required to enter the valleys, and high aspect ratio structures are needed to maximize the surface area in contact with the plasma, thereby making it possible to obtain a given level of optical glucose-measurement sensitivity with a relatively small volume of blood. There is an additional requirement that the hills be wide enough that a sufficient amount of light can propagate into them and, after reflection, can propagate out of them. The method described in the cited prior article produces a texture comprising cones and pillars that conform to the average-distance and aspect-ratio requirements. However, a significant fraction of the cones and pillars are so

  8. High-precision method for determining the position of laser beam focal plane

    SciTech Connect

    Malashko, Ya I; Kleimenov, A N; Potemkin, I B; Khabibulin, V M

    2013-12-31

    The method of wavefront doubled-frequency spherical modulation for determining the laser beam waist position has been simulated and experimentally studied. The error in determining the focal plane position is less than 10{sup -5} D. The amplitude of the control doubled-frequency electric signal is experimentally found to correspond to 12% of the total radiation power. (laser beams)

  9. 14 CFR 25.1395 - Maximum intensities in overlapping beams of forward and rear position lights.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Maximum intensities in overlapping beams of forward and rear position lights. 25.1395 Section 25.1395 Aeronautics and Space FEDERAL AVIATION... Equipment Lights § 25.1395 Maximum intensities in overlapping beams of forward and rear position lights....

  10. 14 CFR 29.1395 - Maximum intensities in overlapping beams of forward and rear position lights.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Maximum intensities in overlapping beams of forward and rear position lights. 29.1395 Section 29.1395 Aeronautics and Space FEDERAL AVIATION... Equipment Lights § 29.1395 Maximum intensities in overlapping beams of forward and rear position lights....

  11. 14 CFR 23.1395 - Maximum intensities in overlapping beams of position lights.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Maximum intensities in overlapping beams of position lights. 23.1395 Section 23.1395 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT... AIRPLANES Equipment Lights § 23.1395 Maximum intensities in overlapping beams of position lights....

  12. 14 CFR 27.1395 - Maximum intensities in overlapping beams of forward and rear position lights.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Maximum intensities in overlapping beams of forward and rear position lights. 27.1395 Section 27.1395 Aeronautics and Space FEDERAL AVIATION... Equipment Lights § 27.1395 Maximum intensities in overlapping beams of forward and rear position lights....

  13. 14 CFR 23.1395 - Maximum intensities in overlapping beams of position lights.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Maximum intensities in overlapping beams of position lights. 23.1395 Section 23.1395 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT... AIRPLANES Equipment Lights § 23.1395 Maximum intensities in overlapping beams of position lights....

  14. 14 CFR 29.1395 - Maximum intensities in overlapping beams of forward and rear position lights.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Maximum intensities in overlapping beams of forward and rear position lights. 29.1395 Section 29.1395 Aeronautics and Space FEDERAL AVIATION... Equipment Lights § 29.1395 Maximum intensities in overlapping beams of forward and rear position lights....

  15. 14 CFR 25.1395 - Maximum intensities in overlapping beams of forward and rear position lights.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Maximum intensities in overlapping beams of forward and rear position lights. 25.1395 Section 25.1395 Aeronautics and Space FEDERAL AVIATION... Equipment Lights § 25.1395 Maximum intensities in overlapping beams of forward and rear position lights....

  16. The Main Injector Beam Position Monitor Front-End Software

    SciTech Connect

    Piccoli, Luciano; Foulkes, Stephen; Votava, Margaret; Briegel, Charles

    2006-11-20

    The front-end software developed for the Main Injector (MI) BPM upgrade is described. The software is responsible for controlling a VME crate equipped with a Motorola PowerPC board running the VxWorks operating system, a custom-made timing board, and up to 10 commercial digitizer boards. The complete MI BPM system is composed of 7 independent units, each collecting data from 19 to 38 BPM pickups. The MI BPM system uses several components already employed on the successful upgrade of another Fermilab machine, the Tevatron, The front-end software framework developed for the Tevatron BPM upgrade is the base for building the MI front-end software. The framework is implemented in C++ as a generic component library (GBPM) that provides an event-driven data acquisition environment. Functionality of GBPM is extended to meet MI BPM requirements, such as the ability to handle and manage data from multiple cycles; perform readout of the digitizer boards without disrupting or missing subsequent cycles; transition between closed orbit and turn-by-turn modes within a cycle, using different filter and timing configurations; and allow the definition of new cycles during normal operation.

  17. The Main Injector Beam Position Monitor Front-End Software

    SciTech Connect

    Piccoli, Luciano; Foulkes, Stephen; Votava, Margaret; Briegel, Charles; /Fermilab

    2006-05-01

    The front-end software developed for the Main Injector (MI) BPM upgrade is described. The software is responsible for controlling a VME crate, equipped with a Motorola PowerPC board running the VxWorks operating system, a custom made timing board and up to 10 commercial digitizer boards. The complete MI BPM system is composed of 7 independent units, each collecting data from 19 to 38 BPM pickups. The MI BPM system uses several components already employed on the successful upgrade of another Fermilab machine, the Tevatron. The front-end software framework developed for the Tevatron BPM upgrade is the base for building the MI front-end software. The framework is implemented in C++ as a generic component library (GBPM) that provides an event-driven data acquisition environment. Functionality of GBPM is extended to meet MI BPM requirements, such as the ability to handle and manage data from multiple cycles; perform readout of the digitizer boards without disrupting or missing subsequent cycles; transition between closed orbit and turn-by-turn modes within a cycle, using different filter and timing configurations; and allow the definition of new cycles during normal operation.

  18. Fast scanner with position monitor for large optical delays

    NASA Astrophysics Data System (ADS)

    Costantino, S.; Libertun, A. R.; Do Campo, P.; Torga, J. R.; Martínez, O. E.

    2001-11-01

    We present a new fast scan system that employs a stepper motor used in a single step oscillating mode and a position monitor device based on a diode laser. The setup used generates delays as large as 105 ps at 10 Hz, with 100% duty cycle. We also introduce a reliable device based on the shadow of a moving cutter with a laser diode as the light source to avoid power fluctuations problems.

  19. Real-Time Coil Position Monitoring System for Biomagnetic Measurements

    NASA Astrophysics Data System (ADS)

    Oyama, Daisuke; Adachi, Yoshiaki; Higuchi, Masanori; Kawai, Jun; Kobayashi, Koichiro; Uehara, Gen

    In this paper, we propose a new method for monitoring the position of marker coils. The marker coil is used for indicating spatial relationship between subject's body and magnetic sensor arrays in biomagnetic measurements, such as magnetoencephalography (MEG) and magnetocardiography (MCG). We developed a real-time marker coil position monitoring system combined with a conventional MEG system. In order to achieve simultaneous measurement of MEG signals and marker signals, we separated their frequency bands. The frequency bands of flux-locked loop (FLL) circuits were separated into three parts by three integrators; low-band, mid-band, and high-band. The second and third bands were assigned for MEG signals and marker signals, respectively. This method can avoid the crosstalk of the marker signals to MEG signals. Marker signals were generated from five marker coils driven by five independent sinusoidal current generators. These signals were continuously measured by the high-band of FLL, and then the coils were localized by FFT processing and solving inverse problem. We succeeded in displaying the localized coil position on a PC monitor once per second in real-time.

  20. Thin silicon strip detectors for beam monitoring in Micro-beam Radiation Therapy

    NASA Astrophysics Data System (ADS)

    Povoli, M.; Alagoz, E.; Bravin, A.; Cornelius, I.; Bräuer-Krisch, E.; Fournier, P.; Hansen, T. E.; Kok, A.; Lerch, M.; Monakhov, E.; Morse, J.; Petasecca, M.; Requardt, H.; Rosenfeld, A. B.; Röhrich, D.; Sandaker, H.; Salomé, M.; Stugu, B.

    2015-11-01

    Microbeam Radiation Therapy (MRT) is an emerging cancer treatment that is currently being developed at the European Synchrotron Radiation Facility (ESRF) in Grenoble, France. This technique uses a highly collimated and fractionated X-ray beam array with extremely high dose rate and very small divergence, to benefit from the dose-volume effect, thus sparing healthy tissue. In case of any beam anomalies and system malfunctions, special safety measures must be installed, such as an emergency safety shutter that requires continuous monitoring of the beam intensity profile. Within the 3DMiMic project, a novel silicon strip detector that can tackle the special features of MRT, such as the extremely high spatial resolution and dose rate, has been developed to be part of the safety shutter system. The first prototypes have been successfully fabricated, and experiments aimed to demonstrate their suitability for this unique application have been performed. Design, fabrication and the experimental results as well as any identified inadequacies for future optimisation are reported and discussed in this paper.

  1. SU-D-213-01: Transparent Photon Detector For The Online Monitoring Of IMRT Beams

    SciTech Connect

    Delorme, R; Arnoud, Y; Fabbro, R; Boyer, B; Rossetto, O; Gallin-Martel, L; Gallin-Martel, M; Pelissier, A; Fonteille, I

    2015-06-15

    Purpose: An innovative Transparent Detector for Radiotherapy (TraDeRa) has been developed. The detector aims at real-time monitoring of modulated beam ahead of the patient during delivery sessions, with a field cover up to 40×40 cm {sup 2}. Methods: TraDeRa consists in a pixelated matrix of ionization chambers with a patented electrodes design. An in-house designed specific integrated circuit allows to extract the signal and provides a real-time map of beam intensity and shape, at the linac pulse-scale. The measurements under irradiation are made with a 6 MV clinical X-Ray beam. Dose calculations are performed with the Monte Carlo code PENELOPE, modeling the full accelerator head and the TraDeRa detector. Results: A 2 % attenuation of the beam was measured in the presence of TraDeRa and the PENELOPE dosimetric study showed no significant modification of the photon beam properties. TraDeRa detects error leaf position as small as 1 mm compared to a reference field, for both static and modulated fields. In addition, measurements are accurate over a large dynamic range from low intensity signals, as inter-leaves leaks, to very high intensities as obtained on the medical line of the European Synchrotron Radiation Facility. The detector is fully operational for conventional and high dose rate beams as FFF modes (up to 2400 MU/min). Conclusion: The current version of TraDeRa shows promising results for IMRT quality assurance (QA), allowing pulse-scale monitoring of the beam and high sensitivity for errors detection. The attenuation is small enough not to hinder the irradiation while keeping the beam upstream of the patient under constant control. A final prototype under development will include 1600 independent electrodes, half of them with a high resolution centered on the beam axis. This compact detector provides an independent set of measurements for a better QA. Funding support : This work was supported by the LABEX PRIMES (ANR-11-LABX-0063) of Universite de Lyon

  2. Data acquisition and online monitoring software for CBM test beams

    NASA Astrophysics Data System (ADS)

    Adamczewski-Musch, J.; Kurz, N.; Linev, S.; Zumbruch, P.

    2012-12-01

    The Compressed Baryonic Matter (CBM) experiment is intended to run at the FAIR facility that is currently being built at GSI in Darmstadt, Germany. For testing of future CBM detector and read-out electronics prototypes, several test beam campaigns have been performed at different locations, such as GSI, COSY, and CERN PS. The DAQ software has to treat various data inputs: standard VME modules on the MBS system, and different kinds of FPGA boards, read via USB, Ethernet, or optical links. The Data Acquisition Backbone Core framework (DABC) is able to combine such different data sources with event-builder processes running on regular Linux PCs. DABC can also retrieve the instrumental set-up data from EPICS slow control systems and insert it into the event data stream for later analysis. Vice versa, the DIM based DABC control protocol has been integrated to the general CBM EPICS IOC by means of an EPICS-DIM interface. Hence the DAQ can be monitored and steered with a CSS based operator GUI. The CBM online monitoring analysis is based on the GSI Go4 framework which can directly connect to DABC online data via sockets, or process stored data from list-mode files. A Go4 sub-framework has been implemented to provide possibility of parallel development of analysis code for different sub-detectors groups. This allows divide the Go4 components up into independent software packages that can run either standalone, or together at the beam-time in a full set-up.

  3. Fast beam conditions monitor BCM1F for the CMS experiment

    NASA Astrophysics Data System (ADS)

    Bell, A.; Castro, E.; Hall-Wilton, R.; Lange, W.; Lohmann, W.; Macpherson, A.; Ohlerich, M.; Rodriguez, N.; Ryjov, V.; Schmidt, R. S.; Stone, R. L.

    2010-03-01

    The CMS Beam Conditions and Radiation Monitoring System, BRM, will support beam tuning, protect the CMS detector from adverse beam conditions, and measure the accumulated dose close to or inside all sub-detectors. It is composed of different sub-systems measuring either the particle flux near the beam pipe with time resolution between nano- and microseconds or the integrated dose over longer time intervals. This paper presents the Fast Beam Conditions Monitor, BCM1F, which is designed for fast flux monitoring measuring both beam halo and collision products. BCM1F is located inside the CMS pixel detector volume close to the beam-pipe. It uses sCVD diamond sensors and radiation hard front-end electronics, along with an analog optical readout of the signals. The commissioning of the system and its successful operation during the first beams of the LHC are described.

  4. Performance of positive ion based high power ion source of EAST neutral beam injector.

    PubMed

    Hu, Chundong; Xie, Yahong; Xie, Yuanlai; Liu, Sheng; Xu, Yongjian; Liang, Lizhen; Jiang, Caichao; Li, Jun; Liu, Zhimin

    2016-02-01

    The positive ion based source with a hot cathode based arc chamber and a tetrode accelerator was employed for a neutral beam injector on the experimental advanced superconducting tokamak (EAST). Four ion sources were developed and each ion source has produced 4 MW @ 80 keV hydrogen beam on the test bed. 100 s long pulse operation with modulated beam has also been tested on the test bed. The accelerator was upgraded from circular shaped to diamond shaped in the latest two ion sources. In the latest campaign of EAST experiment, four ion sources injected more than 4 MW deuterium beam with beam energy of 60 keV into EAST.

  5. Monitoring motion and measuring relative position of the Chang'E-3 rover

    NASA Astrophysics Data System (ADS)

    Liu, Qinghui; Zheng, Xin; Huang, Yong; Li, Peijia; He, Qingbao; Wu, Yajun; Guo, Li; Tang, Mingle

    2014-11-01

    Same-beam very long baseline interferometry observations were performed between the rover and the lander of Chang'E-3 and differential phase delay data were obtained with the minimum random error of about 0.03 ps. These data were used to monitor the rover motions, as small as several centimeters, including movement, turning, and attitude adjustment. The relative position between the rover and the lander was precisely measured with an accuracy of 1 m, which is an improvement of 10 times compared with that of the Apollo project.

  6. Automatic beam position control at Los Alamos Spallation Radiation Effects Facility (LASREF)

    SciTech Connect

    Oothoudt, M.; Pillai, C.; Zumbro, M.

    1997-08-01

    Historically the Los Alamos Spallation Radiation Effects Facility (LASREF) has used manual methods to control the position of the 800 kW, 800 MeV proton beam on targets. New experiments, however, require more stringent position control more frequently than can be done manually for long periods of time. Data from an existing harp is used to automatically adjust steering magnets to maintain beam position to required tolerances.

  7. Position and flux stabilization of X-ray beams produced by double-crystal monochromators for EXAFS scans at the titanium K-edge.

    PubMed

    van Silfhout, Roelof; Kachatkou, Anton; Groppo, Elena; Lamberti, Carlo; Bras, Wim

    2014-03-01

    The simultaneous and active feedback stabilization of X-ray beam position and monochromatic beam flux during EXAFS scans at the titanium K-edge as produced by a double-crystal monochromator beamline is reported. The feedback is generated using two independent feedback loops using separate beam flux and position measurements. The flux is stabilized using a fast extremum-searching algorithm that is insensitive to changes in the synchrotron ring current and energy-dependent monochromator output. Corrections of beam height are made using an innovative transmissive beam position monitor instrument. The efficacy of the feedback stabilization method is demonstrated by comparing the measurements of EXAFS spectra on inhomogeneous diluted Ti-containing samples with and without feedback applied.

  8. Demonstration of the importance of a dedicated neutron beam monitoring system for BNCT facility.

    PubMed

    Chao, Der-Sheng; Liu, Yuan-Hao; Jiang, Shiang-Huei

    2016-01-01

    The neutron beam monitoring system is indispensable to BNCT facility in order to achieve an accurate patient dose delivery. The neutron beam monitoring of a reactor-based BNCT (RB-BNCT) facility can be implemented through the instrumentation and control system of a reactor provided that the reactor power level remains constant during reactor operation. However, since the neutron flux in reactor core is highly correlative to complicated reactor kinetics resulting from such as fuel depletion, poison production, and control blade movement, some extent of variation may occur in the spatial distribution of neutron flux in reactor core. Therefore, a dedicated neutron beam monitoring system is needed to be installed in the vicinity of the beam path close to the beam exit of the RB-BNCT facility, where it can measure the BNCT beam intensity as closely as possible and be free from the influence of the objects present around the beam exit. In this study, in order to demonstrate the importance of a dedicated BNCT neutron beam monitoring system, the signals originating from the two in-core neutron detectors installed at THOR were extracted and compared with the three dedicated neutron beam monitors of the THOR BNCT facility. The correlation of the readings between the in-core neutron detectors and the BNCT neutron beam monitors was established to evaluate the improvable quality of the beam intensity measurement inferred by the in-core neutron detectors. In 29 sampled intervals within 16 days of measurement, the fluctuations in the mean value of the normalized ratios between readings of the three BNCT neutron beam monitors lay within 0.2%. However, the normalized ratios of readings of the two in-core neutron detectors to one of the BNCT neutron beam monitors show great fluctuations of 5.9% and 17.5%, respectively. PMID:26595774

  9. Demonstration of the importance of a dedicated neutron beam monitoring system for BNCT facility.

    PubMed

    Chao, Der-Sheng; Liu, Yuan-Hao; Jiang, Shiang-Huei

    2016-01-01

    The neutron beam monitoring system is indispensable to BNCT facility in order to achieve an accurate patient dose delivery. The neutron beam monitoring of a reactor-based BNCT (RB-BNCT) facility can be implemented through the instrumentation and control system of a reactor provided that the reactor power level remains constant during reactor operation. However, since the neutron flux in reactor core is highly correlative to complicated reactor kinetics resulting from such as fuel depletion, poison production, and control blade movement, some extent of variation may occur in the spatial distribution of neutron flux in reactor core. Therefore, a dedicated neutron beam monitoring system is needed to be installed in the vicinity of the beam path close to the beam exit of the RB-BNCT facility, where it can measure the BNCT beam intensity as closely as possible and be free from the influence of the objects present around the beam exit. In this study, in order to demonstrate the importance of a dedicated BNCT neutron beam monitoring system, the signals originating from the two in-core neutron detectors installed at THOR were extracted and compared with the three dedicated neutron beam monitors of the THOR BNCT facility. The correlation of the readings between the in-core neutron detectors and the BNCT neutron beam monitors was established to evaluate the improvable quality of the beam intensity measurement inferred by the in-core neutron detectors. In 29 sampled intervals within 16 days of measurement, the fluctuations in the mean value of the normalized ratios between readings of the three BNCT neutron beam monitors lay within 0.2%. However, the normalized ratios of readings of the two in-core neutron detectors to one of the BNCT neutron beam monitors show great fluctuations of 5.9% and 17.5%, respectively.

  10. Summary report on beam and radiation generation, monitoring and control (working group 6).

    SciTech Connect

    Power, J. G.; Gordon, D. F.; High Energy Physics; Naval Research Lab.

    2009-01-01

    The discussions of the working group on beam and radiation generation, monitoring, and control (working group 6) at the 2008 advanced accelerator concepts workshop are summarized. The discussions concerned electron injectors, phase space manipulation, beam diagnostics, pulse train generation, intense beam physics, and radiation generation.

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

    NASA Astrophysics Data System (ADS)

    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.

  12. The fast beam condition monitor BCM1F backend electronics upgraded MicroTCA-based architecture

    NASA Astrophysics Data System (ADS)

    Zagozdzinska, Agnieszka A.; Bell, Alan; Dabrowski, Anne E.; Guthoff, Moritz; Hempel, Maria; Henschel, Hans; Karacheban, Olena; Lange, Wolfgang; Lohmann, Wolfgang; Lokhovitskiy, Arkady; Leonard, Jessica L.; Loos, Robert; Miraglia, Marco; Penno, Marek; Pozniak, Krzysztof T.; Przyborowski, Dominik; Stickland, David; Trapani, Pier Paolo; Romaniuk, Ryszard; Ryjov, Vladimir; Walsh, Roberval

    2014-11-01

    The Beam Radiation Instrumentation and Luminosity Project of the CMS experiment, consists of several beam monitoring systems. One system, the upgraded Fast Beams Condition Monitor, is based on 24 single crystal CVD diamonds with a double-pad sensor metallization and a custom designed readout. Signals for real-time monitoring are transmitted to the counting room, where they are received and processed by new back-end electronics designed to extract information on LHC collision, beam induced background and activation products. The Slow Control Driver is designed for the front-end electronics configuration and control. The system architecture and the upgrade status will be presented.

  13. A fast beam loss monitor system for the KEK proton synchrotron complex

    NASA Astrophysics Data System (ADS)

    Holt, J. A.; Kishiro, J.; Arakawa, D.; Hiramatsu, S.

    1991-06-01

    Efforts to increase the intensity of the KEK proton synchrotron have led to the need for a new fast response beam loss monitor system. The design and some prelimitary test results of a new beam loss monitor system are presented.(AIP)

  14. Belle-II VXD radiation monitoring and beam abort with sCVD diamond sensors

    NASA Astrophysics Data System (ADS)

    Adamczyk, K.; Aihara, H.; Angelini, C.; Aziz, T.; Babu, V.; Bacher, S.; Bahinipati, S.; Barberio, E.; Baroncelli, T.; Basith, A. K.; Batignani, G.; Bauer, A.; Behera, P. K.; Bergauer, T.; Bettarini, S.; Bhuyan, B.; Bilka, T.; Bosi, F.; Bosisio, L.; Bozek, A.; Buchsteiner, F.; Casarosa, G.; Ceccanti, M.; Červenkov, D.; Chendvankar, S. R.; Dash, N.; Divekar, S. T.; Doležal, Z.; Dutta, D.; Forti, F.; Friedl, M.; Hara, K.; Higuchi, T.; Horiguchi, T.; Irmler, C.; Ishikawa, A.; Jeon, H. B.; Joo, C.; Kandra, J.; Kang, K. H.; Kato, E.; Kawasaki, T.; Kodyš, P.; Kohriki, T.; Koike, S.; Kolwalkar, M. M.; Kvasnička, P.; Lanceri, L.; Lettenbicher, J.; Mammini, P.; Mayekar, S. N.; Mohanty, G. B.; Mohanty, S.; Morii, T.; Nakamura, K. R.; Natkaniec, Z.; Negishi, K.; Nisar, N. K.; Onuki, Y.; Ostrowicz, W.; Paladino, A.; Paoloni, E.; Park, H.; Pilo, F.; Profeti, A.; Rashevskaya, I.; Rao, K. K.; Rizzo, G.; Rozanska, M.; Sandilya, S.; Sasaki, J.; Sato, N.; Schultschik, S.; Schwanda, C.; Seino, Y.; Shimizu, N.; Stypula, J.; Tanaka, S.; Tanida, K.; Taylor, G. N.; Thalmeier, R.; Thomas, R.; Tsuboyama, T.; Uozumi, S.; Urquijo, P.; Vitale, Lorenzo; Volpi, M.; Watanuki, S.; Watson, I. J.; Webb, J.; Wiechczynski, J.; Williams, S.; Würkner, B.; Yamamoto, H.; Yin, H.; Yoshinobu, T.

    2016-07-01

    The Belle-II VerteX Detector (VXD) has been designed to improve the performances with respect to Belle and to cope with an unprecedented luminosity of 8 ×1035cm-2s-1 achievable by the SuperKEKB. Special care is needed to monitor both the radiation dose accumulated throughout the life of the experiment and the instantaneous radiation rate, in order to be able to promptly react to sudden spikes for the purpose of protecting the detectors. A radiation monitoring and beam abort system based on single-crystal diamond sensors is now under an active development for the VXD. The sensors will be placed in several key positions in the vicinity of the interaction region. The severe space limitations require a challenging remote readout of the sensors.

  15. An MLC-based version for the ecliptic method for the determination of backscatter into the beam monitor chambers in photon beams of medical accelerators.

    PubMed

    Nelli, Flavio Enrico

    2016-03-01

    A very simple method to measure the effect of the backscatter from secondary collimators into the beam monitor chambers in linear accelerators equipped with multi-leaf collimators (MLC) is presented here. The backscatter to the monitor chambers from the upper jaws of the secondary collimator was measured on three beam-matched linacs by means of three methods: this new methodology, the ecliptic method, and assessing the variation of the beam-on time per monitor unit with dose rate feedback disabled. This new methodology was used to assess the backscatter characteristics of asymmetric over-traveling jaws. Excellent agreement between the backscatter values measured using the new methodology introduced here and the ones obtained using the other two methods was established. The experimental values reported here differ by less than 1% from published data. The sensitivity of this novel technique allowed differences in backscatter due to the same opening of the jaws, when placed at different positions on the beam path, to be resolved. The introduction of the ecliptic method has made the determination of the backscatter to the monitor chambers an easy procedure. The method presented here for machines equipped with MLCs makes the determination of backscatter to the beam monitor chambers even easier, and suitable to characterize linacs equipped with over-traveling asymmetric secondary collimators. This experimental procedure could be simply implemented to fully characterize the backscatter output factor constituent when detailed dosimetric modeling of the machine's head is required. The methodology proved to be uncomplicated, accurate and suitable for clinical or experimental environments. PMID:26671445

  16. Operation of the intensity monitors in beam transport lines at Fermilab during Run II¹

    SciTech Connect

    Crisp, J.; Fellenz, B.; Fitzgerald, J.; Heikkinen, D.; Ibrahim, M. A.

    2011-10-06

    The intensity of charged particle beams at Fermilab must be kept within pre-determined safety and operational envelopes in part by assuring all beam within a few percent has been transported from any source to destination. Beam instensity monitors with toroidial pickups provide such beam intensity measurements in the transport lines between accelerators at FNAL. With Run II, much effort was made to continually improve the resolution and accuracy of the system.

  17. Equipment for Beam Current and Electron Energy Monitoring During Industry Irradiation.

    NASA Astrophysics Data System (ADS)

    Zavadtsev, A. A.

    1997-05-01

    The electron beam irradiation sterilization is placed first among all types of medical items sterilization. The quality of sterilization is determined by value of dose, which is in one's turn determined by beam current, electron energy and beam scanning system parameters. Therefore this parameters have to be controlled during the irradiation process. The equipment for beam current and electron energy monitoring allows to control beam current, electron energy spectrum and nominal deflection of electron beam when scanning during the irradiation process each scanning period or, for example, each tenth period by request.

  18. Axial tolerance in the position of aberration compensators placed in a converging beam.

    PubMed

    Morales, A; Servin, M; Malacara, D

    1996-04-01

    To perform a null test of aspherical surfaces we used a computer-generated hologram or a lens or a mirror compensator to compensate the aspherical aberration. When compensating in a convergent light beam the axial position of this hologram or compensator is critical. A holographic compensator to be used in the convergent beam of light was designed and constructed. We have established some relations to determine the tolerance in the axial positioning of these compensators.

  19. Volcano monitoring using the Global Positioning System: Filtering strategies

    USGS Publications Warehouse

    Larson, K.M.; Cervelli, Peter; Lisowski, M.; Miklius, Asta; Segall, P.; Owen, S.

    2001-01-01

    Permanent Global Positioning System (GPS) networks are routinely used for producing improved orbits and monitoring secular tectonic deformation. For these applications, data are transferred to an analysis center each day and routinely processed in 24-hour segments. To use GPS for monitoring volcanic events, which may last only a few hours, real-time or near real-time data processing and subdaily position estimates are valuable. Strategies have been researched for obtaining station coordinates every 15 min using a Kalman filter; these strategies have been tested on data collected by a GPS network on Kilauea Volcano. Data from this network are tracked continuously, recorded every 30 s, and telemetered hourly to the Hawaiian Volcano Observatory. A white noise model is heavily impacted by data outages and poor satellite geometry, but a properly constrained random walk model fits the data well. Using a borehole tiltmeter at Kilauea's summit as ground-truth, solutions using different random walk constraints were compared. This study indicates that signals on the order of 5 mm/h are resolvable using a random walk standard deviation of 0.45 cm/???h. Values lower than this suppress small signals, and values greater than this have significantly higher noise at periods of 1-6 hours. Copyright 2001 by the American Geophysical Union.

  20. A NEW DIFFERENTIAL AND ERRANT BEAM CURRENT MONITOR FOR THE SNS* ACCELERATOR

    SciTech Connect

    Blokland, Willem; Peters, Charles C

    2013-01-01

    A new Differential and errant Beam Current Monitor (DBCM) is being implemented for both the Spallation Neutron Source's Medium Energy Beam Transport (MEBT) and the Super Conducting Linac (SCL) accelerator sections. These new current monitors will abort the beam when the difference between two toroidal pickups exceeds a threshold. The MEBT DBCM will protect the MEBT chopper target, while the SCL DBCM will abort beam to minimize fast beam losses in the SCL cavities. The new DBCM will also record instances of errant beam, such as beam dropouts, to assist in further optimization of the SNS Accelerator. A software Errant Beam Monitor was implemented on the regular BCM hardware to study errant beam pulses. The new system will take over this functionality and will also be able to abort beam on pulse-to-pulse variations. Because the system is based on the FlexRIO hardware and programmed in LabVIEW FPGA, it will be able to abort beam in about 5 us. This paper describes the development, implementation, and initial test results of the DBCM, as well as errant beam examples.

  1. Focused beam reflectance measurement to monitor nimodipine precipitation process.

    PubMed

    Xu, Xiaoming; Siddiqui, Akhtar; Khan, Mansoor A

    2013-11-18

    Crystallization of nimodipine in liquid-filled soft gelatin capsule during storage was reported for some commercial products, resulting in product recalls due to product quality and more importantly safety concerns. In this study, a real time particle monitoring tool, focused beam reflectance measurement, was used to evaluate the precipitation conditions of nimodipine in co-solvents. Upon water addition, two particle populations were discovered, appearing at different percentage of water content. Two transitions (i.e. sudden increase in particle counts) were observed, possibility related to nucleation and crystal growth of nimodipine. Furthermore, lowering storage temperature increased the tendency of nimodipine precipitation. Most critically, it was determined that with certain excipient, the drug precipitation occurred at approximately 7% (w/w) water content. Considering that all the orally administered liquid filled soft gelatin capsule shells contain residue water content as plasticizer, moisture transfer from the shell to the formulation may occur during long term storage, resulting in drug precipitation, particularly under cold temperature conditions.

  2. Laser-Beam-Absorption Chemical-Species Monitor

    NASA Technical Reports Server (NTRS)

    Gersh, Michael; Goldstein, Neil; Lee, Jamine; Bien, Fritz; Richtsmeier, Steven

    1996-01-01

    Apparatus measures concentration of chemical species in fluid medium (e.g., gaseous industrial process stream). Directs laser beam through medium, and measures intensity of beam after passage through medium. Relative amount of beam power absorbed in medium indicative of concentration of chemical species; laser wavelength chosen to be one at which species of interest absorbs.

  3. RESULTS OF BACKGROUND SUBTRACTION TECHNIQUES ON THE SPALLATION NEUTRON SOURCE BEAM LOSS MONITORS

    SciTech Connect

    Pogge, James R; Zhukov, Alexander P

    2010-01-01

    Recent improvements to the Spallation Neutron Source (SNS) beam loss monitor (BLM) designs have been made with the goal of significantly reducing background noise. This paper outlines this effort and analyzes the results. The significance of this noise reduction is the ability to use the BLM sensors [1], [2], [3] distributed throughout the SNS accelerator as a method to monitor activation of components as well as monitor beam losses.

  4. Ion Chambers for Monitoring the NuMI Neutrino Beam at Fermilab

    SciTech Connect

    Indurthy, Dharmaraj; Keisler, Ryan; Kopp, Sacha; Mendoza, Steven; Proga, Marek; Pavlovich, Zarko; Zwaska, Robert; Harris, Deborah; Marchionni, Alberto; Morfin, Jorge; Erwin, Albert; Ping Huicana; Velissaris, Christos; Naples, Donna; Northacker, Dave; McDonald, Jeff; Diwan, Milind; Viren, Brett

    2004-11-10

    The Neutrinos at the Main Injector (NuMI) beamline will deliver an intense muon neutrino beam by focusing a beam of mesons into a long evacuated decay volume. The beam must be steered with 1-mRad angular accuracy toward the Soudan Underground Laboratory in northern Minnesota. We have built 4 arrays of ionization chambers to monitor the neutrino beam direction and quality. The arrays are located at 4 stations downstream of the decay volume, and measure the remnant hadron beam and tertiary muons produced along with neutrinos in meson decays. We review how the monitors will be used to make beam quality measurements, and as well review chamber construction details, radiation damage testing, calibration, and test beam results.

  5. Performance Studies of the Vibration Wire Monitor on the Test Stand with Low Energy Electron Beam

    NASA Astrophysics Data System (ADS)

    Okabe, Kota; Yoshimoto, Masahiro; Kinsho, Michikazu

    In the high intensity proton accelerator as the Japan Proton Accelerator Research Complex (J-PARC) accelerators, serious radiation and residual dose is induced by a small beam loss such a beam halo. Therefore, diagnostics of the beam halo formation is one of the most important issues to control the beam loss. For the beam halo monitor, the vibration wire monitor (VWM) has a potential for investigating the beam halo and weak beam scanning. The VWM has a wide dynamic range, high resolution and the VWM is not susceptible to secondary electrons and electric noises. We have studied the VWM features as a new beam-halo monitor on the test stand with low energy electron gun. The frequency shift of the irradiated vibration wire was confirmed about wire material and the electron beam profile measured by using the VWM was consistent with the results of the Faraday cup measurement. Also we calculated a temperature distribution on the vibration wire which is irradiated by the electron beam with the numerical simulation. The simulations have been fairly successful in reproducing the transient of the irradiated vibration wire frequency measured by test stand experiments. In this paper, we will report a result of performance evaluation for the VWM on the test stands and discuss the VWM for beam halo diagnostic

  6. Effects of mirror distortion by thermal deformation in an interferometry beam size monitor system at PLS-II

    NASA Astrophysics Data System (ADS)

    Hwang, Ji-Gwang; Kim, Eun-San; Kim, Changbum; Huang, Jung-Yun; Kim, Dotae

    2016-10-01

    Extraction mirrors installed at the most upstream position of interferometry beam size monitor are frequently used for measuring the beam size in storage rings. These mirrors receive the high power synchrotron radiation and are distorted owing to the heat distribution that depends on the position on the mirror surface. The distortion of the mirror changes the effective separation of the slit in the interferometry beam size monitor. Estimation of the effects of the front-end mirror distortion is important for measuring the beam size accurately. In this paper, we present the result of the numerical simulation of the temperature distribution and thermal expansion of the front-end mirror using ANSYS code, the theoretical basis of the effects of mirror distortion and compare with experimental results from Pohang Light Source II (PLS-II) at the Pohang Accelerator Laboratory (PAL). The equipment in the beam diagnosis line in PLS-II and experimental set-up for measuring the distortion of the front-end mirror using a multi-hole square array Hartmann screen are described.

  7. A free jet (supersonic), molecular beam source with automatized, 50 nm precision nozzle-skimmer positioning.

    PubMed

    Eder, S D; Samelin, B; Bracco, G; Ansperger, K; Holst, B

    2013-09-01

    Low energy (thermal) free jet (supersonic) molecular beams are used in a range of applications from surface science and surface deposition to quantum coherence and gas kinetics experiments. A free jet molecular beam is created by a gas expansion from a high pressure reservoir through a small aperture (nozzle). The nozzle typically has a diameter of 2-20 μm. The central part of the beam is selected using a skimmer, typically up to 500 μm in diameter. Recent years have seen the introduction of highly spatially confined beam sources based on micrometer skimmers and micrometer or even sub-micrometer nozzles. Such sources have been applied, for example, in the investigation of superfluidity and in neutral helium microscopy. However, up till now no source design allowing the precise positioning of the micro-skimmer relative to the nozzle has been available. This is an important issue because the relative position of skimmer and nozzle can influence the beam properties considerably. Here we present the design and implementation of a new molecular beam source, which allows an automatized, 50 nm precision positioning of the skimmer relative to the nozzle. The source is liquid nitrogen cooled and the temperature can be controlled between 110 K and 350 K with a temperature fluctuation of less than ±0.1 K over several hours. Beam intensity measurements using a 5 μm nozzle and a skimmer 5 μm in diameter are presented for stagnation pressures po in the range 3-180 bars. A 2D beam profile scan, using a 9.5 μm skimmer and a 5 μm nozzle is presented as a further documentation of the versatility of the new design and as an illustration of the influence of the relative skimmer-nozzle position on the beam properties.

  8. Non-intrusive beam power monitor for high power pulsed or continuous wave lasers

    DOEpatents

    Hawsey, Robert A.; Scudiere, Matthew B.

    1993-01-01

    A system and method for monitoring the output of a laser is provided in which the output of a photodiode disposed in the cavity of the laser is used to provide a correlated indication of the laser power. The photodiode is disposed out of the laser beam to view the extraneous light generated in the laser cavity whose intensity has been found to be a direct correlation of the laser beam output power level. Further, the system provides means for monitoring the phase of the laser output beam relative to a modulated control signal through the photodiode monitor.

  9. An LHCb general-purpose acquisition board for beam and background monitoring at the LHC

    NASA Astrophysics Data System (ADS)

    Alessio, F.; Guzik, Z.; Jacobsson, R.

    2011-01-01

    In this paper we will present an LHCb custom-made acquisition board which was developed for a continuous beam and background monitoring during LHC operations at CERN. The paper describes both the conceptual design and its performance, and concludes with results from the first period of beam operations at the LHC. The main purpose of the acquisition board is to process signals from a pair of beam pickups to continuously monitor the intensity of each bunch, and to monitor the phase of the arrival time of each proton bunch with respect to the LHC bunch clock. The extreme versatility of the board also allowed the LHCb experiment to build a high-speed and high-sensitivity readout system for a fast background monitor based on a pair of plastic scintillators. The board has demonstrated very good performance and proved to be conceptually valid during the first months of operations at the LHC. Connected to the beam pickups, it provides the LHCb experiment with a real-time measurement of the total intensity of each beam and of the arrival time of each beam at the LHCb Interaction Point. It also monitors the LHC filling scheme and the beam current per bunch at a continuous rate of 40 MHz, and assures a proper global timing of LHCb. The continuous readout of the scintillators at bunch clock speed provides the LHCb experiment with high-resolution information about the beam halo and fast losses during both injection and circulating beam. It has also provided valuable information to the LHC during machine commissioning with beam. Recent results also shows that it could contribute as a luminosity monitor independent from the LHCb experiment readout system. Beam, background and luminosity measurements are continuously fed back to the LHC in the data exchange framework between the experiments and the LHC machine aimed at improving efficiently the experimental conditions real-time.

  10. A beam deflection apparatus with high resolution for monitoring TGS crystal growth

    SciTech Connect

    Musazzi, S.; Affinito, A.; Stenzel, C.; Fabritius, G.

    1996-12-31

    A beam deflection apparatus with a high resolution has been developed which allows monitoring of temperature and concentration gradients in the region around a TGS (triglycine sulphate) crystal growing from an aqueous solution. The developed optical setup consists of two measuring arms that allow inspection of the test region along two perpendicular directions. With a lateral position sensing device the deflection of a mildly focused laser beam traversing the medium to be tested have been measured along one inspection axis, while a two-dimensional analysis of the test region is performed in the orthogonal direction by means of a properly focused light blade and a CCD camera. Experimental verification of the technique has been performed utilizing TGS crystal growth by means of the cooled sting method. The experiment takes place in a double-wall glass cell, the temperature of the TGS crystal can be adjusted independently from the solution temperature. Systematic measurements have been performed which allow to characterize concentration gradients and thermal convection in the vicinity of the crystal. Analysis of experimental results shows the high sensitivity of this method. This technique is well suited as a diagnostic tool for monitoring and controlling crystal growth experiments in microgravity.

  11. AAE and AAOMR Joint Position Statement: Use of Cone Beam Computed Tomography in Endodontics 2015 Update.

    PubMed

    2015-10-01

    The following statement was prepared by the Special Committee to Revise the Joint American Association of Endodontists/American Academy of Oral and Maxillofacial Radiology Position on Cone Beam Computed Tomography, and approved by the AAE Board of Directors and AAOMR Executive Council in May 2015. AAE members may reprint this position statement for distribution to patients or referring dentists.

  12. Apparatus for monitoring X-ray beam alignment

    DOEpatents

    Steinmeyer, Peter A.

    1991-10-08

    A self-contained, hand-held apparatus is provided for minitoring alignment of an X-ray beam in an instrument employing an X-ray source. The apparatus includes a transducer assembly containing a photoresistor for providing a range of electrical signals responsive to a range of X-ray beam intensities from the X-ray beam being aligned. A circuit, powered by a 7.5 VDC power supply and containing an audio frequency pulse generator whose frequency varies with the resistance of the photoresistor, is provided for generating a range of audible sounds. A portion of the audible range corresponds to low X-ray beam intensity. Another portion of the audible range corresponds to high X-ray beam intensity. The transducer assembly may include an a photoresistor, a thin layer of X-ray fluorescent material, and a filter layer transparent to X-rays but opaque to visible light. X-rays from the beam undergoing alignment penetrate the filter layer and excite the layer of fluorescent material. The light emitted from the fluorescent material alters the resistance of the photoresistor which is in the electrical circuit including the audio pulse generator and a speaker. In employing the apparatus, the X-ray beam is aligned to a complete alignment by adjusting the X-ray beam to produce an audible sound of the maximum frequency.

  13. Bunch-length and beam-timing monitors in the SLC final focus

    SciTech Connect

    Zimmermann, F.; Yocky, G.; Whittum, D.H.; Seidel, M.; Ng, C.K.; McCormick, D.; Bane, K.L.F.

    1998-07-01

    During the 1997/98 luminosity run of the Stanford Linear Collider (SLC), two novel RF-based detectors were brought into operation, in order to monitor the interaction-point (IP) bunch lengths and fluctuations in the relative arrival time of the two colliding beams. Both bunch length and timing can strongly affect the SLC luminosity and had not been monitored in previous years. The two new detectors utilize a broad-band microwave signal, which is excited by the beam through a ceramic gap in the final-focus beam pipe and transported outside of the beam line vault by a 160-ft long X-Band waveguide. The authors describe the estimated luminosity reduction due to bunch-length drift and IP timing fluctuation, the monitor layout, the expected responses and signal levels, calibration measurements, and beam observations.

  14. Flying wire beam profile monitors at the KEK PS main ring

    NASA Astrophysics Data System (ADS)

    Igarashi, Susumu; Arakawa, Dai; Koba, Kiyomi; Sato, Hikaru; Toyama, Takeshi; Yoshii, Masahito

    2002-04-01

    Transverse beam profile monitors called "Flying Wires" have been installed and operated at the 12-GeV main ring of the KEK Proton Synchrotron. A carbon wire of 7 μm in diameter scans the beam with a maximum speed of 20 m/s and produces secondary particles from the beam-wire scattering. The minimum wire material and fast scanning speed have been chosen to achieve the precise profile measurement and minimum beam destruction because the requirements are critical for the lowest kinetic energy of 500 MeV. The basic performance has been thoroughly tested. A new stroboscopic procedure has been established to reconstruct beam profiles that rapidly change with a time scale of 1 ms or less. The monitors have demonstrated capability of obtaining profitable information for the mechanism of the halo formation and beam loss.

  15. Transverse Beam Halo Measurements at High Intensity Neutrino Source (HINS) using Vibrating Wire Monitor

    SciTech Connect

    Chung, M.; Hanna, B.; Scarpine, V.; Shiltsev, V.; Steimel, J.; Artinian, S.; Arutunian, S.

    2015-02-26

    The measurement and control of beam halos will be critical for the applications of future high-intensity hadron linacs. In particular, beam profile monitors require a very high dynamic range when used for the transverse beam halo measurements. In this study, the Vibrating Wire Monitor (VWM) with aperture 60 mm was installed at the High Intensity Neutrino Source (HINS) front-end to measure the transverse beam halo. A vibrating wire is excited at its resonance frequency with the help of a magnetic feedback loop, and the vibrating and sensitive wires are connected through a balanced arm. The sensitive wire is moved into the beam halo region by a stepper motor controlled translational stage. We study the feasibility of the vibrating wire for the transverse beam halo measurements in the low-energy front-end of the proton linac.

  16. Method and apparatus for real time imaging and monitoring of radiotherapy beams

    DOEpatents

    Majewski, Stanislaw; Proffitt, James; Macey, Daniel J.; Weisenberger, Andrew G.

    2011-11-01

    A method and apparatus for real time imaging and monitoring of radiation therapy beams is designed to preferentially distinguish and image low energy radiation from high energy secondary radiation emitted from a target as the result of therapeutic beam deposition. A detector having low sensitivity to high energy photons combined with a collimator designed to dynamically image in the region of the therapeutic beam target is used.

  17. Energy monitoring device for 1.5-2.4 MeV electron beams

    NASA Astrophysics Data System (ADS)

    Fuochi, P. G.; Lavalle, M.; Martelli, A.; Kovács, A.; Mehta, K.; Kuntz, F.; Plumeri, S.

    2010-03-01

    An easy-to-use and robust energy monitoring device has been developed for reliable detection of day-to-day small variations in the electron beam energy, a critical parameter for quality control and quality assurance in industrial radiation processing. It has potential for using on-line, thus providing real-time information. Its working principle is based on the measurement of currents, or charges, collected by two aluminium absorbers of specific thicknesses (dependent on the beam energy), insulated from each other and positioned within a faraday cup-style aluminium cage connected to the ground. The device has been extensively tested in the energy range of 4-12 MeV under standard laboratory conditions at Institute of Isotopes and CNR-ISOF using different types of electron accelerators; namely, a TESLA LPR-4 LINAC (3-6 MeV) and a L-band Vickers LINAC (7-12 MeV), respectively. This device has been also tested in high power electron beam radiation processing facilities, one equipped with a 7-MeV LUE-8 linear accelerator used for crosslinking of cables and medical device sterilization, and the other equipped with a 10 MeV Rhodotron TT100 recirculating accelerator used for in-house sterilization of medical devices. In the present work, we have extended the application of this method to still lower energy region, i.e. from 1.5 to 2.4 MeV. Also, we show that such a device is capable of detecting deviation in the beam energy as small as 40 keV.

  18. UPGRADE TO INITIAL BPM ELECTRONICS MODULE AND BEAMLINE COMPONENTS FOR CALIBRATION OF THE LEDA BEAM POSITION MEASUREMENTS

    SciTech Connect

    D.S. BARR; J.D. GILPATRICK; R.B. SHURTER

    2001-06-01

    The Low-Energy Demonstration Accelerator (LEDA), designed and built at the Los Alamos National Laboratory, is part of the Accelerator Production of Tritium (APT) program and provides a platform for measuring high-power proton beam-halo formation. Beam Position Monitors (BPMs) are placed along the FODO lattice and the HEBT. The BPM systems employing log-ratio processor electronics have recently been upgraded for all fifteen BPMs along the accelerator. Two types of calibration are now used. The first corrects for errors within the electronics module and the log-amp transfer function non-conformity. The second is a single-point routine used to correct for cable plant attenuation differences. This paper will also cover the new switching systems used for various system calibration modes as well as various results from LEDA beam runs. New switching algorithms were implemented in order to remove sensitive electronic switches from within the beam tunnel radiation environment. Attention will be paid to the calibration algorithms and switching system interactions, and how well they work in practice.

  19. Reply to comment on 'Proton beam monitor chamber calibration'.

    PubMed

    Gomà, Carles; Lorentini, Stefano; Meer, David; Safai, Sairos

    2016-09-01

    This reply shows that the discrepancy of about 3% between Faraday cup dosimetry and reference dosimetry using a cylindrical ionization chamber found in Gomà (2014 Phys. Med. Biol. 59 4961-71) seems to be due to an overestimation of the beam quality correction factors tabulated in IAEA TRS-398 for the cylindrical chamber used, rather than to 'unresolved problems with Faraday cup dosimetry', as suggested by Palmans and Vatnitsky (2016 Phys. Med. Biol. 61 6585-93). Furthermore, this work shows that a good agreement between reference dosimetry and Faraday cup dosimetry is possible, provided accurate beam quality correction factors for proton beams are used. The review on W air values presented by Palmans and Vatnitsky is believed to be inaccurate, as it is based on the imprecise assumption of ionization chamber perturbation correction factors in proton beams being equal to unity. PMID:27535895

  20. Analysis of the Reactor Position Independent Monitor (PIM) Diagnostic

    SciTech Connect

    Hayes-Sterbenz, Anna Catherine

    2014-07-17

    In this note I analyze the physics determining the proposed reactor position independent monitor (PIM), which is the ratio (240Pu/239Pu)1/3 × (135Cs/137Cs)1/2. The PIM ratios in any reactor fuel is shown to increase monotonically with the time over which the fuel is irradiated. This is because the Cs ratio determines the neutron flux, while the Pu isotopic ratio is determined by the flux times the irradiation time. If the irradiation time for all fuel rods across the reactor is fixed, the PIM ratio is approximately constant in all rods. However, no information can be extracted from the PIM ratio on Pu isotopics unless both the flux (or Cs ratio) and the irradiation time (from, say, Ru isotopics) are known separately, i.e., the PIM ratio is not a fundamental parameter of any reactor. Thus, unless the PIM ratio has been measured for the specific fuel under interrogation, no information can be deduced from measurements or reactor simulations of PIM ratios in different fuel from the same reactor. However, if a PIM measurement has been in one spent fuel rod from a given reactor, all other rods that are known to have been in the reactor for the same irradiation period can be assumed to have approximately the same PIM ratio.

  1. High-current CW beam profile monitors using transition radiation at CEBAF

    NASA Astrophysics Data System (ADS)

    Piot, P.; Denard, J.-C.; Adderley, P.; Capek, K.; Feldl, E.

    1997-01-01

    One way of measuring the profile of CEBAF's low-emittance, high-power beam is to use the optical transition radiation (OTR) emitted from a thin foil surface when the electron beam passes through it. We present the design of a monitor using the forward OTR emitted from a 0.25-μm carbon foil. We believe that the monitor will resolve three main issues: i) whether the maximum temperature of the foil stays below the melting point, ii) whether the beam loss remains below 0.5%, in order not to trigger the machine protection system, and iii) whether the monitor resolution (unlike that of synchrotron radiation monitors) is better than the product λγ. It seems that the most serious limitation for CEBAF is the beam loss due to beam scattering. We present results from Keil's theory and simulations from the computer code GEANT as well as measurements with aluminum foils with a 45-MeV electron beam. We also present a measurement of a 3.2-GeV beam profile that is much smaller than λγ, supporting Rule and Fiorito's calculations of the OTR resolution limit due to diffraction.

  2. Advanced Beam Energy Spread Monitoring Systems and Their Control at Jefferson Lab

    SciTech Connect

    Pavel Chevtsov

    2005-03-01

    Two Synchrotron Light Interferometers (SLI) have been in use at Jefferson Lab for more than one year. Each SLI is an absolutely not invasive beam diagnostic device routinely monitoring the transverse beam size and beam energy spread in a wide range of beam energies and intensities with a very high accuracy. The SLI are automated with the use of distributed, multi-level, and multi-component control software. The paper describes the SLI configuration, the structure of the SLI control software and its performance.

  3. A POSSIBLE SYNCHROTRON LIGHT BEAM PROFILE MONITOR IN RHIC.

    SciTech Connect

    TRBOJEVIC, D.

    1998-06-26

    This report examines the possibility of observing transverse beam profiles by using synchrotron light emission from the 100 GeV/nucleon heavy-ion gold beam in the Relativistic Heavy Ion Collider (RHIC). Synchrotron radiation experiences a shift towards higher photon energy when the magnetic field at the end of a dipole varies rapidly over a short distance. Synchrotron light signals from high energy (larger than 400 GeV) proton beams have already been routinely used to observe the transverse beam profiles at the SPS in CERN and at the TEVATRON at Fermilab. Because of the modest relativistic factor of the fully stripped stored gold ions in RHIC this ''push'' towards higher critical energy is not large enough to place the synchrotron light within the visible region of the spectrum. The critical wavelength remains within the infrared region. A 77K cooled infrared array detector with 160 elements, made of PbSe (Lead salt) could be used for beam profile detection. It would cover the wavelength range between 1 and 6 microns, with maximum sensitivity at a wavelength of 4.5 microns.

  4. Bunch-length and beam-timing monitors in the SLC final focus

    SciTech Connect

    Zimmermann, F.; Yocky, G.; Whittum, D. H.; Seidel, M.; Ng, C. K.; McCormick, D.; Bane, K. L. F.

    1999-07-12

    During the 1997/98 luminosity run of the Stanford Linear Collider (SLC) two novel RF-based detectors were brought into operation, in order to monitor the interaction-point (IP) bunch lengths and fluctuations in the relative arrival time of the two colliding beams. Both bunch length and timing can strongly affect the SLC luminosity and had not been monitored in previous years. The two new detectors utilize a broad-band microwave signal, which is excited by the beam through a ceramic gap in the final-focus beam pipe and transported outside of the beamline vault by a 160-ft long X-Band waveguide. We describe the estimated luminosity reduction due to bunch-length drift and IP timing fluctuation, the monitor layout, the expected responses and signal levels, calibration measurements, and beam observations.

  5. Bunch-length and beam-timing monitors in the SLC final focus

    SciTech Connect

    Zimmermann, F.; Yocky, G.; Whittum, D.H.; Seidel, M.; Ng, C.K.; McCormick, D.; Bane, K.L.

    1999-07-01

    During the 1997/98 luminosity run of the Stanford Linear Collider (SLC) two novel RF-based detectors were brought into operation, in order to monitor the interaction-point (IP) bunch lengths and fluctuations in the relative arrival time of the two colliding beams. Both bunch length and timing can strongly affect the SLC luminosity and had not been monitored in previous years. The two new detectors utilize a broad-band microwave signal, which is excited by the beam through a ceramic gap in the final-focus beam pipe and transported outside of the beamline vault by a 160-ft long X-Band waveguide. We describe the estimated luminosity reduction due to bunch-length drift and IP timing fluctuation, the monitor layout, the expected responses and signal levels, calibration measurements, and beam observations. {copyright} {ital 1999 American Institute of Physics.}

  6. Plasma Charge Current for Controlling and Monitoring Electron Beam Welding with Beam Oscillation

    PubMed Central

    Trushnikov, Dmitriy; Belenkiy, Vladimir; Shchavlev, Valeriy; Piskunov, Anatoliy; Abdullin, Aleksandr; Mladenov, Georgy

    2012-01-01

    Electron beam welding (EBW) shows certain problems with the control of focus regime. The electron beam focus can be controlled in electron-beam welding based on the parameters of a secondary signal. In this case, the parameters like secondary emissions and focus coil current have extreme relationships. There are two values of focus coil current which provide equal value signal parameters. Therefore, adaptive systems of electron beam focus control use low-frequency scanning of focus, which substantially limits the operation speed of these systems and has a negative effect on weld joint quality. The purpose of this study is to develop a method for operational control of the electron beam focus during welding in the deep penetration mode. The method uses the plasma charge current signal as an additional informational parameter. This parameter allows identification of the electron beam focus regime in electron-beam welding without application of additional low-frequency scanning of focus. It can be used for working out operational electron beam control methods focusing exactly on the welding. In addition, use of this parameter allows one to observe the shape of the keyhole during the welding process. PMID:23242276

  7. Plasma charge current for controlling and monitoring electron beam welding with beam oscillation.

    PubMed

    Trushnikov, Dmitriy; Belenkiy, Vladimir; Shchavlev, Valeriy; Piskunov, Anatoliy; Abdullin, Aleksandr; Mladenov, Georgy

    2012-12-14

    Electron beam welding (EBW) shows certain problems with the control of focus regime. The electron beam focus can be controlled in electron-beam welding based on the parameters of a secondary signal. In this case, the parameters like secondary emissions and focus coil current have extreme relationships. There are two values of focus coil current which provide equal value signal parameters. Therefore, adaptive systems of electron beam focus control use low-frequency scanning of focus, which substantially limits the operation speed of these systems and has a negative effect on weld joint quality. The purpose of this study is to develop a method for operational control of the electron beam focus during welding in the deep penetration mode. The method uses the plasma charge current signal as an additional informational parameter. This parameter allows identification of the electron beam focus regime in electron-beam welding without application of additional low-frequency scanning of focus. It can be used for working out operational electron beam control methods focusing exactly on the welding. In addition, use of this parameter allows one to observe the shape of the keyhole during the welding process.

  8. Beam Extinction Monitoring in the Mu2e Experiment

    SciTech Connect

    Prebys, Eric; Bartoszek, Larry; Gaponenko, Andrei; Kasper, Peter

    2015-06-01

    The Mu2e Experiment at Fermilab will search for the conversion of a muon to an electron in the field of an atomic nucleus with unprecedented sensitivity. The experiment requires a beam consisting of proton bunches approximately 200ns FW long, separated by 1.7 microseconds, with no out-of-time protons at the 10⁻¹⁰ fractional level. The verification of this level of extinction is very challenging. The proposed technique uses a special purpose spectrometer which will observe particles scattered from the production target of the experiment. The acceptance will be limited such that there will be no saturation effects from the in-time beam. The precise level and profile of the out-of-time beam can then be built up statistically, by integrating over many bunches.

  9. Position-sensitive radiation monitoring (surface contamination monitor). Innovative technology summary report

    SciTech Connect

    Not Available

    1999-06-01

    The Shonka Research Associates, Inc. Position-Sensitive Radiation Monitor both detects surface radiation and prepares electronic survey map/survey report of surveyed area automatically. The electronically recorded map can be downloaded to a personal computer for review and a map/report can be generated for inclusion in work packages. Switching from beta-gamma detection to alpha detection is relatively simple and entails moving a switch position to alpha and adjusting the voltage level to an alpha detection level. No field calibration is required when switching from beta-gamma to alpha detection. The system can be used for free-release surveys because it meets the federal detection level sensitivity limits requires for surface survey instrumentation. This technology is superior to traditionally-used floor contamination monitor (FCM) and hand-held survey instrumentation because it can precisely register locations of radioactivity and accurately correlate contamination levels to specific locations. Additionally, it can collect and store continuous radiological data in database format, which can be used to produce real-time imagery as well as automated graphics of survey data. Its flexible design can accommodate a variety of detectors. The cost of the innovative technology is 13% to 57% lower than traditional methods. This technology is suited for radiological surveys of flat surfaces at US Department of Energy (DOE) nuclear facility decontamination and decommissioning (D and D) sites or similar public or commercial sites.

  10. Monte Carlo simulation of neutron noise effects on beam position determination at the National Ignition Facility

    NASA Astrophysics Data System (ADS)

    Awwal, Abdul A. S.; Leach, Richard R.; Datte, Philip; Manuel, Anastacia

    2013-09-01

    Images obtained through charged coupled device (CCD) cameras in the National Ignition Facility (NIF) are crucial to precise alignment of the 192 laser beams to the NIF target-chamber center (TCC). Cameras in and around the target chamber are increasingly exposed to the effects of neutron radiation as the laser power is increased for high energy fusion experiments. NIF was carefully designed to operate under these conditions. The present work examines the degradation of the measured TCC camera position accuracy resulting from the effects of neutron radiation on the sensor and verifies operation within design specifications. Both synthetic and real beam images are used for measuring position degradation. Monte Carlo simulations based on camera performance models are used to create images with added neutron noise. These models predict neutron induced camera noise based on exposure estimates of the cumulative single-shot fluence in the NIF environment. The neutron induced noise images are used to measure beam positions on a target calculated from the alignment images with the added noise. The effects of this noise are also determined using noise artifacts from real camera images viewing TCC to estimate beam position uncertainty.

  11. 14 CFR 27.1395 - Maximum intensities in overlapping beams of forward and rear position lights.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Maximum intensities in overlapping beams of forward and rear position lights. 27.1395 Section 27.1395 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL CATEGORY...

  12. 14 CFR 27.1395 - Maximum intensities in overlapping beams of forward and rear position lights.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Maximum intensities in overlapping beams of forward and rear position lights. 27.1395 Section 27.1395 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL CATEGORY...

  13. Beam rider for an Articulated Robot Manipulator (ARM) accurate positioning of long flexible manipulators

    NASA Technical Reports Server (NTRS)

    Malachowski, M. J.

    1990-01-01

    Laser beam positioning and beam rider modules were incorporated into the long hollow flexible segment of an articulated robot manipulator (ARM). Using a single laser beam, the system determined the position of the distal ARM endtip, with millimetric precision, in six degrees of freedom, at distances of up to 10 meters. Preliminary designs, using space rated technology for the critical systems, of a two segmented physical ARM, with a single and a dual degree of freedom articulation, were developed, prototyped, and tested. To control the positioning of the physical ARM, an indirect adaptive controller, which used the mismatch between the position of the laser beam under static and dynamic conditions, was devised. To predict the behavior of the system and test the concept, a computer simulation model was constructed. A hierarchical artificially intelligent real time ADA operating system program structure was created. The software was designed for implementation on a dedicated VME bus based Intel 80386 administered parallel processing multi-tasking computer system.

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

    SciTech Connect

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

    2005-06-08

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

  15. PRECISE ANGLE MONITOR BASED ON THE CONCEPT OF PENCIL-BEAM INTERFEROMETRY

    SciTech Connect

    QIAN,S.; TAKACS,P.

    2000-07-30

    The precise angle monitoring is a very important metrology task for research, development and industrial applications. Autocollimator is one of the most powerful and widely applied instruments for small angle monitoring, which is based on the principle of geometric optics. In this paper the authors introduce a new precise angle monitoring system, Pencil-beam Angle Monitor (PAM), base on pencil beam interferometry. Its principle of operation is a combination of physical and geometrical optics. The angle calculation method is similar to the autocollimator. However, the autocollimator creates a cross image but the precise pencil-beam angle monitoring system produces an interference fringe on the focal plane. The advantages of the PAM are: high angular sensitivity, long-term stability character making angle monitoring over long time periods possible, high measurement accuracy in the order of sub-microradian, simultaneous measurement ability in two perpendicular directions or on two different objects, dynamic measurement possibility, insensitive to the vibration and air turbulence, automatic display, storage and analysis by use of the computer, small beam diameter making the alignment extremely easy and longer test distance. Some test examples are presented.

  16. APPARATUS FOR CONTROLLING THE POSITION OF AN ION BEAM IN A CALUTRON

    DOEpatents

    Lawrence, E.O.

    1958-01-01

    ABS>This patent relates to improvements in electric discharge devices of the calutron type for separation of the isotopes of an element from the freely occurring composition. The improvement constitutes means for the continuous control of the path of an ion beam to obtain maximum reception in a receiver compartment. Withdrawal of the ions from the source is accomplished by an accelerator electrode placed at a positive potential with respect to the receiver. The ions are projected through a magnetic field perpendicular to the direction of motion towards a receiver. In order to obtain a signal representative of the magnitude of ions received from a particular ion-beam in its compartment, an electrode is disposed in the compartment. The signal from the compartment electrode controls the voltage of the acccleratimg electrodc through appropriate circuitry to maintain the path of the particular ion beam optimum for maximum ion current in the compartment.

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

    SciTech Connect

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

    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.

  18. Thermometric- and Acoustic-Based Beam Power Monitor for Ultra-Bright X-Rays

    SciTech Connect

    Bentsen, Gregory; /Rochester U. /SLAC

    2010-08-25

    A design for an average beam power monitor for ultra-bright X-ray sources is proposed that makes simultaneous use of calorimetry and radiation acoustics. Radiation incident on a solid target will induce heating and ultrasonic vibrations, both of which may be measured to give a fairly precise value of the beam power. The monitor is intended for measuring ultra-bright Free-Electron Laser (FEL) X-ray beams, for which traditional monitoring technologies such as photo-diodes or scintillators are unsuitable. The monitor consists of a Boron Carbide (B{sub 4}C) target designed to absorb most of the incident beam's energy. Resistance temperature detectors (RTD) and piezoelectric actuators are mounted on the outward faces of the target to measure the temperature changes and ultrasonic vibrations induced by the incident beam. The design was tested using an optical pulsed beam (780 nm, 120 and 360 Hz) from a Ti:sapphire oscillator at several energies between 0.8 and 2.6 mJ. The RTDs measured an increase in temperature of about 10 K over a period of several minutes. The piezoelectric sensors recorded ringing acoustic oscillations at 580 {+-} 40 kHz. Most importantly, the amplitude of the acoustic signals was observed to scale linearly with beam power up to 2 mJ of pulse energy. Above this pulse energy, the vibrational signals became nonlinear. Several causes for this nonlinearity are discussed, including amplifier saturation and piezoelectric saturation. Despite this nonlinearity, these measurements demonstrate the feasibility of such a beam power measurement device. The advantage of two distinct measurements (acoustic and thermometric) provides a useful method of calibration that is unavailable to current LCLS diagnostics tools.

  19. Leak Rate Test for a Fiber Beam Monitor Contained in a Vacuum for the Muon g-2 Experiment

    NASA Astrophysics Data System (ADS)

    O'Mara, Bridget; Lane, Noel; Gross, Eisen; Gray, Frederick; Muon g-2 Collaboration

    2014-09-01

    The muon g-2 experiment at Fermilab aims to measure the muon anomalous magnetic moment with a precision of 0.14 parts per million (ppm). The measurement will build on the Brookhaven-based E821 experiment, which yielded results suggesting new physics such as supersymmetry. The Fiber Beam Monitors (FBMs) are used in the experiment to determine the position and observe the motion of a muon beam and monitor the properties of the beam over time. The FBMs support a 9 cm × 8 cm ``harp'' with 7 scintillating fibers separated from each other by 13 mm, each with a diameter of 0.5 mm. The experiment requires a vacuum of less than 1 ×10-6 Torr to prevent trapping of electrons ionized from the residual gas by the electrostatic quadrupoles. To meet this requirement the FBMs must have a leak rate of less than 5 ×10-5 Torr L/s. We have constructed a vacuum system to simulate these conditions and have determined the leak rate of the FBMs within the constructed vacuum apparatus. This leak rate will be reported, along with preliminary results from tests of the light output from the scintillating fibers. The muon g-2 experiment at Fermilab aims to measure the muon anomalous magnetic moment with a precision of 0.14 parts per million (ppm). The measurement will build on the Brookhaven-based E821 experiment, which yielded results suggesting new physics such as supersymmetry. The Fiber Beam Monitors (FBMs) are used in the experiment to determine the position and observe the motion of a muon beam and monitor the properties of the beam over time. The FBMs support a 9 cm × 8 cm ``harp'' with 7 scintillating fibers separated from each other by 13 mm, each with a diameter of 0.5 mm. The experiment requires a vacuum of less than 1 ×10-6 Torr to prevent trapping of electrons ionized from the residual gas by the electrostatic quadrupoles. To meet this requirement the FBMs must have a leak rate of less than 5 ×10-5 Torr L/s. We have constructed a vacuum system to simulate these conditions

  20. IN SITU PRECISE ANGLE MONITORING ON SYNCHROTRON RADIATION MONOCHROMATOR BY USE OF PENCIL BEAM INTERFEROMETER.

    SciTech Connect

    QIAN,S.TAKACS,P.DONG,Q.HULBERT,S.

    2003-08-25

    Monochromator is a very important and precise instrument used in beam lines at synchrotron radiation facilities. We need to know if there is actual thermal distortion on gratings resulting in the degradation of the monochromator resolution. We need to know the characteristics of the grating rotation. It is possible to make a simple but precise in-situ distortion monitoring and rotation angle test of the grating by use of a precise pencil beam angle monitor. We have made preliminary measurements on a monochrometer grating of an undulator beam line X1B at Brookhaven National Laboratory. We monitored a small amount of angle variation on the grating. We detected 1.7 {micro}rad backlash (P-V) of the grating controlling system.

  1. Piezoelectric-based smart sensing system for I-beam structural health monitoring

    NASA Astrophysics Data System (ADS)

    Zhang, Chen; Zhang, Haifeng; Yu, Tzuyang; Wang, Xingwei

    2016-04-01

    In recent decades, the I-beam has become one of the most important engineering structural components being applied in areas such as mechanical, civil, and constructional engineering. To ensure safety and proper maintenance, an effective and accurate structural health monitoring method/system for I-beams is urgently needed. This paper proposes a smart sensing system for I-beam crack detection that is based on the energy diffusivity (attenuation) between two individual piezoelectric transducers (PZTs). Sensor (one of the PZTs) responses are analyzed and applied to characterize the health status of the I-beam. Lab experiments are carried out for effective evaluation of this approach in structural health monitoring. The characteristics of crack distribution are studied by calculating and analyzing the energy diffusivity variation of the sensor responses to artificially cuttings to the I-beam. Moreover, instead of utilizing an actuator and a sensor, the system employs a couple of PZTs sensors, which offer the potential for in-field, in situ sensing with the sensor arrays. This smart sensing system can be applied in railway, metro, and iron-steel structures for I-beam health monitoring applications.

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

    SciTech Connect

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

    2011-11-01

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

  3. Beam waist position study for surface modification of polymethyl-methacrylate with femtosecond laser pulses

    NASA Astrophysics Data System (ADS)

    Caballero-Lucas, F.; Florian, C.; Fernández-Pradas, J. M.; Morenza, J. L.; Serra, P.

    2016-06-01

    Femtosecond lasers are versatile tools to process transparent materials. This optical property poses an issue for surface modification. In this case, laser radiation would not be absorbed at the surface unless the beam is just focused there. Otherwise, absorption would take place in the bulk leaving the surface unperturbed. Therefore, strategies to position the material surface at the laser beam waist with high accuracy are essential. We investigated and compared two options to achieve this aim: the use of reflectance data and transmittance measurements across the sample, both obtained during z-scans with pulses from a 1027 nm wavelength laser and 450 fs pulse duration. As the material enters the beam waist region, a reflectance peak is detected while a transmittance drop is observed. With these observations, it is possible to control the position of the sample surface with respect to the beam waist with high resolution and attain pure surface modification. In the case of polymethyl-methacrylate (PMMA), this resolution is 0.6 μm. The results prove that these methods are feasible for submicrometric processing of the surface.

  4. Profile Monitor SEMs for the NuMI Beam at Fermilab

    SciTech Connect

    Indurthy, Dharmaraj; Kopp, Sacha; Proga, Marek; Pavlovich, Zarko

    2004-11-10

    The Neutrinos at the Main Injector (NuMI) project will extract 120-GeV protons from the FNAL Main Injector in 8.56-{mu}sec spills of 4 x 1013 protons every 1.9 sec. We have designed secondary emission monitor (SEM) detectors to measure beam profile and halo along the proton beam transport line. The SEMs are Ti foils 5 {mu}m in thickness segmented in either 1-mm or 0.5-mm pitch strips, resulting in beam loss {approx}5 x 10-6. We discuss aspects of the mechanical design, calculations of expected beam heating, and results of a beam test at the 8-GeV transport line to MiniBoone at FNAL.

  5. Advanced laser-based tracking device for motor vehicle lane position monitoring and steering assistance

    NASA Astrophysics Data System (ADS)

    Bachalo, William D.; Inenaga, Andrew; Schuler, Carlos A.

    1995-12-01

    Aerometrics is developing an innovative laser-diode based device that provides a warning signal when a motor-vehicle deviates from the center of the lane. The device is based on a sensor that scans the roadway on either side of the vehicle and determines the lateral position relative to the existing painted lines marking the lane. No additional markings are required. A warning is used to alert the driver of excessive weaving or unanticipated departure from the center of the lane. The laser beams are at invisible wavelengths to that operation of the device does not pose a distraction to the driver or other motorists: When appropriate markers are not present on the road, the device is capable of detecting this condition and warn the driver. The sensor system is expected to work well irrespective of ambient light levels, fog and rain. This sensor has enormous commercial potential. It could be marketed as an instrument to warn drivers that they are weaving, used as a research tool to monitor driving patterns, be required equipment for those previously convicted of driving under the influence, or used as a backup sensor for vehicle lateral position control. It can also be used in storage plants to guide robotic delivery vehicles. In this paper, the principles of operation of the sensor, and the results of Aerometrics ongoing testing will be presented.

  6. Summary report of working group 5: Beam and radiation generation, monitoring, and control

    SciTech Connect

    Church, Mike; Kim, Ki-Yong; /Maryland U.

    2010-01-01

    This paper summarizes the activities and presentations of Working Group 5 of the Advanced Accelerator Concepts Workshop held at Annapolis, Maryland in June 2010. Working Group 5 touched on a broad range of topics in the fields of beam and radiation generation and their monitoring and control. These topics were not comprehensively covered in this Workshop, but rather the Working Group concentrated on specific new developments and recent investigations. The Working Group divided its sessions into four broad categories: cathodes and electron guns, radiation generation, beam diagnostics, and beam control and dynamics. This summary is divided into the same structure.

  7. Diamond detector for high rate monitors of fast neutrons beams

    SciTech Connect

    Giacomelli, L.; Rebai, M.; Cippo, E. Perelli; Tardocchi, M.; Fazzi, A.; Andreani, C.; Pietropaolo, A.; Frost, C. D.; Rhodes, N.; Schooneveld, E.; Gorini, G.

    2012-06-19

    A fast neutron detection system suitable for high rate measurements is presented. The detector is based on a commercial high purity single crystal diamond (SDD) coupled to a fast digital data acquisition system. The detector was tested at the ISIS pulsed spallation neutron source. The SDD event signal was digitized at 1 GHz to reconstruct the deposited energy (pulse amplitude) and neutron arrival time; the event time of flight (ToF) was obtained relative to the recorded proton beam signal t{sub 0}. Fast acquisition is needed since the peak count rate is very high ({approx}800 kHz) due to the pulsed structure of the neutron beam. Measurements at ISIS indicate that three characteristics regions exist in the biparametric spectrum: i) background gamma events of low pulse amplitudes; ii) low pulse amplitude neutron events in the energy range E{sub dep}= 1.5-7 MeV ascribed to neutron elastic scattering on {sup 12}C; iii) large pulse amplitude neutron events with E{sub n} < 7 MeV ascribed to {sup 12}C(n,{alpha}){sup 9}Be and 12C(n,n')3{alpha}.

  8. Large aperture vibrating wire monitor with two mechanically coupled wires for beam halo measurements

    SciTech Connect

    Arutunian, S. G.; Avetisyan, A. E.; Davtyan, M. M.; Harutyunyan, G. S.; Vasiniuk, I. E.; Chung, M.; Scarpine, V.

    2014-03-01

    Development of a new type of Vibrating Wire Monitor (VWM), which has two mechanically coupled wires (vibrating and target), is presented. The new monitor has a much larger aperture size than the previous model of the VWM, and thus allows us to measure transverse beam halos more effectively. A prototype of such a large aperture VWM with a target wire length of 60 mm was designed, manufactured, and bench-tested. Initial beam measurements have been performed at the Fermilab High Intensity Neutrino Source (HINS) facility, and key results are presented.

  9. Beam-loss monitoring system with free-air ionization chambers

    NASA Astrophysics Data System (ADS)

    Nakagawa, H.; Shibata, S.; Hiramatsu, S.; Uchino, K.; Takashima, T.

    1980-08-01

    A monitoring system for proton beam losses was installed in the proton synchrotron at the National Laboratory for High Energy Physics in Japan (KEK). The system consists of 56 air ionization chambers (AIC) for radiation detectors, 56 integrators, 56 variable gain amplifiers, two multiplexers, a computer interface circuit, a manual controller and a high tension power supply. The characteristics of the AIC, time resolution, radiation measurement upper limit saturation, kinetic energy dependence of the sensitivity, chamber activation effect, the beam loss detection system and the results of observations with the monitoring system are described.

  10. Focusing intense electron beams using a positive space charge cloud plasma lens

    NASA Astrophysics Data System (ADS)

    Goncharov, A.; Dobrovolskiy, A.; Litovko, I.; Gushenets, V.; Oks, E.

    2014-05-01

    An original plasma-optical device for focusing and manipulating negatively charged particle beams by a dynamic cloud of non-magnetized free positive ions and magnetically isolated electrons produced by a toroidal plasma source such as an anode layer thruster has recently been proposed and explored. In such systems, the electrons are separated from the ions by the relatively strong magnetic field in the discharge channel. The accelerated ions are weakly affected by the magnetic field, owing to their mass. Here, we describe the current status of ongoing research and development of a wide-aperture electrostatic plasma lens with a positive space charge cloud for focusing and manipulating large-area, high-current electron beams. The new modified magnetic system was simulated, designed and tested for minimal aberrations. In this work, we present new simulation results of the further lens development.

  11. Polarized Positive and Negative Muon Beams to perform DVCS Measurements at COMPASS

    SciTech Connect

    D'Hose, Nicole

    2009-09-02

    The high energies available at CERN, and the option of using either positive or negative polarized muon beams, make the fixed-target COMPASS set-up a unique place for studying GPDs, through Deeply Virtual Compton Scattering (DVCS). A GPD program is part of the Medium and Long Term Plans at COMPASS [1]. This contribution presents the methodology and the goal of such experiments.

  12. Two self-referencing methods for the measurement of beam spot position

    SciTech Connect

    Nyiri, Balazs J.; Smale, Jason R.; Gerig, Lee H.

    2012-12-15

    Purpose: Two quantitative methods of measuring electron beam spot position with respect to the collimator axis of rotation (CAOR) are described. Methods: Method 1 uses a cylindrical ion chamber (IC) mounted on a jig corotational with the collimator making the relationship among the chamber, jaws, and CAOR fixed and independent of collimator angle. A jaw parallel to the IC axis is set to zero and the IC position adjusted so that the IC signal is approximately 50% of the open field value, providing a large dose gradient in the region of the IC. The cGy/MU value is measured as a function of collimator rotation, e.g., every 30 Degree-Sign . If the beam spot does not lie on the CAOR, the signal from the ion chamber will vary with collimator rotation. Based on a measured spatial sensitivity, the distance of the beam spot from the CAOR can be calculated from the IC signal variation with rotation. The 2nd method is image based. Two stainless steel rods, 3 mm in diameter, are mounted to a jig attached to the Linac collimator. The rods, offset from the CAOR, lay in different planes normal to the CAOR, one at 158 cm SSD and the other at 70 cm SSD. As the collimator rotates the rods move tangent along an envelope circle, the centers of which are on the CAOR in their respective planes. Three images, each at a different collimator rotation, containing the shadows of both rods, are acquired on the Linac EPID. At each angle the shadow of the rods on the EPID defines lines tangent to the projection of the envelope circles. From these the authors determine the projected centers of the two circles at different heights. From the distance of these two points using the two heights and the source to EPID distance, the authors calculate the distance of the beam spot from the CAOR. Measurements with all two techniques were performed on an Elekta Linac. Measurements were performed with the beam spot in nominal clinical position and in a deliberately offset position. Measurements were also

  13. TH-C-17A-09: Direct Visualization and Monitoring of Medical Radiation Beams in Air

    SciTech Connect

    Fahimian, B; Ceballos, A; Turkcan, S; Kapp, D; Pratx, G

    2014-06-15

    Purpose: Radiation therapy errors are rare but potentially catastrophic. Recent fatal incidents could have been avoided by utilizing real-time methods of monitoring delivery of radiation during treatment. However, few existing methods are practical enough to be used routinely. The study presents the first experimental demonstration of a novel non-perturbing method of monitoring radiation therapy through the phenomena of air scintillation. Methods: Monitoring of radiation delivery was devised by leveraging the phenomena of nitrogen excitation in air by ionizing radiation. The excitation induced weak luminescence in the 300–400 nm range, a process called air scintillation. An electron-multiplication charge-coupled device camera (f/0.95 lens; 440 nm shortpass) was set-up in a clinical treatment vault and was used to capture air scintillation images of kilovoltage and megavoltage beams. Monte Carlo simulations were performed to determine the correlation of radiation dose to air scintillation. Results: Megavoltage beams from a Varian Clinac 21EX and kilovoltage beams from an orthovoltage unit (50 kVp, 30 mA) were visualized with a relatively short exposure time (10 s). Cherenkov luminescence produced in a plastic transparent phantom did not interfere with detection of air scintillation. The image intensity displayed an inverse intensity falloff (r{sup 2} = 0.89) along the central axis and was proportional to dose rate (r{sup 2} = 0.9998). As beam energy increased, the divergence of the imaged beam decreased. Last, air scintillation was visualized during a simulated total skin irradiation electron treatment. Conclusion: Air scintillation can be clinically detected to monitor a radiation beam in an inexpensive and non-perturbing manner. This new method is advantageous in monitoring for gross delivery and uniquely capable of wide area in a single acquisition, such as the case for online verification of total body / skin / lymphoid irradiation treatments.

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

    NASA Astrophysics Data System (ADS)

    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.

  15. Stereo optical tracker for standoff monitoring of position and orientation

    NASA Astrophysics Data System (ADS)

    Sherman, W. D.; Houk, T. L.; Saint Clair, J. M.; Sjoholm, P. F.; Voth, M. D.

    2009-01-01

    A Precision Optical Measurement System (POMS) has been designed, constructed and tested for tracking the position (x, y, z) and orientation (roll, pitch, yaw) of models in Boeing's 9-77 Compact Radar Range. A stereo triangulation technique is implemented using two remote sensor units separated by a known baseline. Each unit measures pointing angles (azimuth and elevation) to optical targets on a model. Four different reference systems are used for calibration and alignment of the system's components and two platforms. Pointing angle data and calibration corrections are processed at high rates to give near real-time feedback to the mechanical positioning system of the model. The positional accuracy of the system is +/- .010 inches at a distance of 85 feet while using low RCS reflective tape targets. The precision measurement capabilities and applications of the system are discussed.

  16. Characteristics of flattening filter free beams at low monitor unit settings

    SciTech Connect

    Akino, Yuichi; Ota, Seiichi; Inoue, Shinichi; Mizuno, Hirokazu; Sumida, Iori; Yoshioka, Yasuo; Ogawa, Kazuhiko; Isohashi, Fumiaki

    2013-11-15

    Purpose: Newer linear accelerators (linacs) have been equipped to deliver flattening filter free (FFF) beams. When FFF beams are used for step-and-shoot intensity-modulated radiotherapy (IMRT), the stability of delivery of small numbers of monitor units (MU) is important. The authors developed automatic measurement techniques to evaluate the stability of the dose profile, dose linearity, and consistency. Here, the authors report the performance of the Artiste™ accelerator (Siemens, Erlangen, Germany) in delivering low-MU FFF beams.Methods: A 6 MV flattened beam (6X) with 300 MU/min dose rate and FFF beams of 7 (7XU) and 11 MV (11XU), each with a 500 MU/min dose rate, were measured at 1, 2, 3, 5, 8, 10, and 20 MU settings. For the 2000 MU/min dose rate, the 7 (7XUH) and 11 MV (11XUH) beams were set at 10, 15, 20, 25, and 30 MU because of the limits of the minimum MU settings. Beams with 20 × 20 and 10 × 10 cm{sup 2} field sizes were alternately measured ten times in intensity modulated (IM) mode, with which Siemens linacs regulate beam delivery for step-and-shoot IMRT. The in- and crossplane beam profiles were measured using a Profiler™ Model 1170 (Sun Nuclear Corporation, Melbourne, FL) in multiframe mode. The frames of 20 × 20 cm{sup 2} beams were identified at the off-axis profile. The 6X beam profile was normalized at the central axis. The 7 and 11 MV FFF beam profiles were rescaled to set the dose at the central axis at 145% and 170%, respectively. Point doses were also measured using a Farmer-type ionization chamber and water-equivalent solid phantom to evaluate the linearity and consistency of low-MU beam delivery. The values displayed on the electrometer were recognized with a USB-type camera and read with open-source optical character recognition software.Results: The symmetry measurements of the 6X, 7XU, and 11XU beam profiles were better than 2% for beams ≥2 MU and improved with increasing MU. The variations in flatness of FFF beams ≥2 MU were

  17. Texturing Blood-Glucose-Monitoring Optics Using Oxygen Beams

    NASA Technical Reports Server (NTRS)

    Banks, Bruce

    2005-01-01

    A method has been invented for utilizing directed, hyperthermal oxygen atoms and ions for texturing tips of polymeric optical fibers or other polymeric optical components for use in optical measurement of concentration of glucose in blood. The required texture of the sensory surface of such a component amounts to a landscape of microscopic hills having high aspect ratios (hills taller than they are wide), with an average distance between hills of no more than about 5 m. This limit on the average distance between hills is chosen so that blood cells (which are wider) cannot enter the valleys between the hills, where they could obstruct optical sensing of glucose in the blood plasma. On the other hand, the plasma is required to enter the valleys, and a high aspect ratio is intended to maximize the hillside and valley surface area in contact with the plasma, thereby making it possible to obtain a given level of optical glucose- measurement sensitivity with a relatively small volume of blood. The present method of texturing by use of directed, hyperthermal (particle energy >1 eV) oxygen atoms and ions stands in contrast to a prior method of texturing by use of thermal monatomic oxygen characterized by a temperature of the order of 0.5 eV. The prior method yields low-aspect- ratio (approximately hemispherical) craters that are tens of microns wide . too wide to exclude blood cells. The figure schematically depicts parts of a typical apparatus for texturing according to the present method. One or more polymeric optical components to be textured (e.g., multiple optical fibers bundled together for simultaneous processing) are mounted in a vacuum chamber facing a suitable ion- or atom-accelerating device capable of generating a beam of oxygen atoms and/or ions having kinetic energies >1 eV. Typically, such a device includes a heated cathode, in which case it is desirable to interpose a water-cooled thermal-radiation shield to prevent melting of the polymeric component(s) to

  18. Monitoring roof beam lateral displacement at the waste isolation pilot plant

    SciTech Connect

    Terrill, L.J.; Lewis, R.E.

    1996-08-01

    Lateral displacement in the immediate roof beam at the Waste Isolation Pilot Plant (WIPP) is a significant factor in assessment of excavation performance for the design of ground control systems. Information on roof beam lateral displacement, expansion, fracture formation, as well as excavation convergence, is gathered using a variety of manually and remotely read instruments. Visual observations are also used when possible. This paper describes the methods used to measure lateral displacement, or offset, at the WIPP. Offset magnitudes are determined by the degree of occlusion in drillholes that intersect the offset plane. The Borehole Lateral Displacement Sensor (BLDS) was developed for installation at WIPP to monitor offset at a high degree of accuracy at a short reading frequency. Offset measurements have historically been obtained by visual estimation of borehole occlusion. Use of the BLDS will enable relationships between time dependent roof beam lateral displacement and expansion to be established in much shorter periods than is possible using visual observations. The instrument will also allow remote monitoring of roof beam displacement in areas where visual estimations are not possible. Continued monitoring of roof beam displacement, convergence, and expansion, is integral to timely and pertinent assessments of WIPP excavation performance.

  19. The beam bunching and transport system of the Argonne positive ion injector

    SciTech Connect

    Den Hartog, P.K.; Bogaty, J.M.; Bollinger, L.M.; Clifft, B.E.; Pardo, R.C.; Shepard, K.W.

    1989-01-01

    A new positive ion injector (PII) is currently under construction at Argonne that will replace the existing 9-MV tandem electrostatic accelerator as an injector into ATLAS. It consists of an electron-cyclotron resonance-ion source on a 350-kV platform injecting into a superconducting linac optimized for very slow (..beta.. less than or equal to .007 c) ions. This combination can potentially produce even higher quality heavy-ion beams than are currently available from the tandem since the emittance growth within the linac is largely determined by the quality of the bunching and beam transport. The system we have implemented uses a two-stage bunching system, composed of a 4-harmonic gridded buncher located on the ECR high-voltage platform and a room temperature spiral-loaded buncher of novel design. A sinusoidal beam chopper is used for removal of tails. The beam transport is designed to provide mass resolution of M/..delta..M > 250 and a doubly-isochronous beamline is used to minimize time spread due to path length differences. 4 refs., 2 figs.

  20. A Toroidal Charge Monitor for High-Energy Picosecond Electron Beams

    SciTech Connect

    Simmons, Robert H.; Ng, Johnny S.T.

    2007-03-28

    A monitor system suitable for the accurate measurement of the total charge of a 2-ps 28.5 GeV electron beam over a large dynamic range is described. Systematic uncertainties and results on absolute calibration, resolution, and long-term stability are presented.

  1. Diamond detector for beam profile monitoring in COMET experiment at J-PARC

    NASA Astrophysics Data System (ADS)

    &Cbreve; erv, M.; Sarin, P.; Pernegger, H.; Vageeswaran, P.; Griesmayer, E.

    2015-06-01

    We present the design and initial prototype results of a proton beam profile monitor for the COMET experiment at J-PARC. The goal of COMET is to look for charged lepton flavor violation by direct μ to e conversion at a sensitivity of 10-19. The 8 GeV proton beam pulsed at 100 ns with 1010 protons/s will be used to create muons through pion production and decay. In the final experiment, the proton flux will be raised to 1014 protons/s to increase the sensitivity. These requirements of harsh radiation tolerance and fast readout make diamond a good choice for constructing a beam profile monitor in COMET. We present first results of the characterization of single crystal diamond (scCVD) sourced from a new company 2A SYSTEMS Singapore. Our measurements indicate excellent charge collection and high carrier mobility down to cryogenic temperatures.

  2. Distributed beam loss monitor based on the Cherenkov effect in an optical fiber

    NASA Astrophysics Data System (ADS)

    Maltseva, Yu; Emanov, F. A.; Petrenko, A. V.; Prisekin, V. G.

    2015-05-01

    This review discusses a distributed beam loss monitor which is based on the Cherenkov effect in an optical fiber and which has been installed at the VEPP-5 Injection Complex at the Budker Institute of Nuclear Physics. The principle of the device operation consists in detecting the Cherenkov radiation generated in an optical fiber by relativistic charged particles that are produced in an electromagnetic shower when highly relativistic beam particles (electrons or positrons) hit the accelerator vacuum chamber wall. Our experiments used a photomultiplier tube (PMT) to detect the Cherenkov light. Knowing when the PMT signal arrives tells us where the beam loss occurs. Using a 20-m-long optical fiber allowed a detector spatial resolution of 3 m. The way to improve the resolution is to optimize the monitor working conditions and optical fiber and PMT parameters, potentially leading to a resolution of as fine as 0.5 m according to our estimates.

  3. Neutron beam monitoring for time-of-flight facilities with gaseous detectors

    NASA Astrophysics Data System (ADS)

    Aza, Eleni; Magistris, Matteo; Murtas, Fabrizio; Puddu, Silvia; Silari, Marco

    2016-01-01

    Triple Gas Electron Multipliers (GEM) for slow and fast neutrons were employed at the n_TOF facility at CERN as online beam imaging monitors and for energy spectra measurements via the time-of-flight technique. The detectors were exposed to the neutron spectrum ranging from thermal to 1 GeV, produced by spallation of 20 GeV/c protons in a lead target with a maximum intensity of 7·1012 protons per pulse. The spectrum and the 2D count distribution of the neutron beam were measured and compared at two distances from the target, 185 m and 200 m. The detectors showed radiation hardness, linear response and the ability to monitor the beam profile online with high spatial resolution.

  4. Accounting for low-frequency synchrotron X-ray beam position fluctuations for dynamic visualizations.

    PubMed

    Hinebaugh, J; Challa, P R; Bazylak, A

    2012-11-01

    Synchrotron X-ray radiography on beamline 05B1-1 at the Canadian Light Source Inc. was employed to study dynamic liquid water transport in the porous electrode materials of polymer electrolyte membrane fuel cells. Dynamic liquid water distributions were quantified for each radiograph in a sequence, and non-physical liquid water measurements were obtained. It was determined that the position of the beam oscillated vertically with an amplitude of ~25 µm at the sample and a frequency of ~50 mHz. In addition, the mean beam position moved linearly in the vertical direction at a rate of 0.74 µm s(-1). No evidence of horizontal oscillations was detected. In this work a technique is presented to account for the temporal and spatial dependence of synchrotron beam intensity, which resulted in a significant reduction in false water thickness. This work provides valuable insight into the treatment of radiographic time-series for capturing dynamic processes from synchrotron radiation.

  5. Diamond pad detector telescope for beam conditions and luminosity monitoring in ATLAS

    NASA Astrophysics Data System (ADS)

    Mikuž, M.; Cindro, V.; Dolenc, I.; Frais-Kölbl, H.; Gorišek, A.; Griesmayer, E.; Kagan, H.; Kramberger, G.; Mandić, I.; Niegl, M.; Pernegger, H.; Trischuk, W.; Weilhammer, P.; Zavrtanik, M.

    2007-09-01

    Beam conditions and the potential detector damage resulting from their anomalies have pushed the LHC experiments to plan their own monitoring devices in addition to those provided by the machine. ATLAS decided to build a telescope composed of two stations with four diamond pad detector modules each, placed symmetrically around the interaction point at z=±183.8cm and r˜55mm (η˜4.2). Equipped with fast electronics it allows time-of-flight separation of events resulting from beam anomalies from normally occurring p p interactions. In addition it will provide a coarse measurement of the LHC luminosity in ATLAS. Ten detector modules have been assembled and subjected to tests, from characterization of bare diamonds to source and beam tests. Preliminary results of beam test in the CERN PS indicate a signal-to-noise ratio of 14±2.

  6. A new multi-strip ionization chamber used as online beam monitor for heavy ion therapy

    NASA Astrophysics Data System (ADS)

    Xu, Zhiguo; Mao, Ruishi; Duan, Limin; She, Qianshun; Hu, Zhengguo; Li, He; Lu, Ziwei; Zhao, Qiecheng; Yang, Herun; Su, Hong; Lu, Chengui; Hu, Rongjiang; Zhang, Junwei

    2013-11-01

    A multi-strip ionization chamber has been built for precise and fast monitoring of the carbon beam spatial distribution at Heavy Ion Researched Facility of Lanzhou Cooling Storing Ring (HIRFL-CSR). All the detector's anode, cathode and sealed windows are made by 2 μm aluminized Mylar film in order to minimize the beam lateral deflection. The sensitive area of the detector is (100×100) mm2, with the anode segmented in 100 strips, and specialized front-end electronics has been developed for simplifying the data acquisition and quick feedback of the relevant parameters to beam control system. It can complete one single beam profile in 200 μs.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

  9. Hybrid BD / GPS Positioning for Deformation Monitoring Under Denied Environments

    NASA Astrophysics Data System (ADS)

    Peng, Zhenzhong; Li, Qianxia; Xia, Linyuan

    2016-09-01

    In the era of multiple satellite navigation and positioning, there are still many remained issues to be tackled in order to satisfy varied applications for various sectors. These include availability, accuracy, integrity, vulnerability and others. To explore feasibility of deformation monitoring under dam and steep slope environments, we investigated features of hybrid BD / GPS positioning and monitoring performance. Results indicate that hybrid satellites can further facilitate precise positioning for deformation monitoring on restricted regions. A static network in near real time mode is designed to exhibit essential sensitivity for deformation monitoring under different network connectivity. Analysis shows that under given network design matrix, contributions from hybrid BD / GPS have enhanced network sensitivity and ensured monitoring performance under challenged scenarios. Related tests combining with application to stringent dam monitoring have been conducted to exemplify sensitivity changes along vital engineering directions and optimal schemes for network configuration.

  10. Estimation of effective imaging dose for kilovoltage intratreatment monitoring of the prostate position during cancer radiotherapy

    NASA Astrophysics Data System (ADS)

    Ng, J. A.; Booth, J.; Poulsen, P.; Kuncic, Z.; Keall, P. J.

    2013-09-01

    Kilovoltage intratreatment monitoring (KIM) is a novel real-time localization modality where the tumor position is continuously measured during intensity modulated radiation therapy (IMRT) or intensity modulated arc therapy (IMAT) by a kilovoltage (kV) x-ray imager. Adding kV imaging during therapy adds radiation dose. The additional effective dose is quantified for prostate radiotherapy and compared to dose from other localization modalities. The software PCXMC 2.0 was used to calculate the effective dose delivered to a phantom as a function of imager angle and field size for a Varian On-Board Imager. The average angular effective dose was calculated for a field size of 6 cm × 6 cm. The average angular effective dose was used in calculations for different treatment scenarios. Treatment scenarios considered were treatment type and fractionation. For all treatment scenarios, (i.e. conventionally fractionated and stereotactic body radiotherapy (SBRT), IMRT and IMAT), the total KIM dose at 1 Hz ranged from 2-10 mSv. This imaging dose is less than the Navotek radioactive implant dose (64 mSv) and a standard SBRT cone beam computed tomography pretreatment scan dose (22 mSv) over an entire treatment regime. KIM delivers an acceptably low effective dose for daily use as a real-time image-guidance method for prostate radiotherapy.

  11. A Four Channel Beam Current Monitor Data Acquisition System Using Embedded Processors

    SciTech Connect

    Wheat, Jr., Robert Mitchell; Dalmas, Dale A.; Dale, Gregory E.

    2015-08-11

    Data acquisition from multiple beam current monitors is required for electron accelerator production of Mo-99. A two channel system capable of recording data from two beam current monitors has been developed, is currently in use, and is discussed below. The development of a cost-effective method of extending this system to more than two channels and integrating of these measurements into an accelerator control system is the main focus of this report. Data from these current monitors is digitized, processed, and stored by a digital data acquisition system. Limitations and drawbacks with the currently deployed digital data acquisition system have been identified as have been potential solutions, or at least improvements, to these problems. This report will discuss and document the efforts we've made in improving the flexibility and lowering the cost of the data acquisition system while maintaining the minimum requirements.

  12. The VANILLA sensor as a beam monitoring device for X-ray radiation therapy.

    PubMed

    Velthuis, J J; Hugtenburg, R P; Cussans, D; Perry, M; Hall, C; Stevens, P; Lawrence, H; McKenzie, A

    2014-01-01

    Cancer treatments such as intensity-modulated radiotherapy (IMRT) require increasingly complex methods to verify the accuracy and precision of the treatment delivery. In vivo dosimetry based on measurements made in an electronic portal imaging device (EPID) has been demonstrated. The distorting effect of the patient anatomy on the beam intensity means it is difficult to separate changes in patient anatomy from changes in the beam intensity profile. Alternatively, upstream detectors scatter and attenuate the beam, changing the energy spectrum of the beam, and generate contaminant radiation such as electrons. We used the VANILLA device, a Monolithic Active Pixel Sensor (MAPS), to measure the 2D beam profile of a 6 MV X-ray beam at Bristol Hospital in real-time in an upstream position to the patient without clinically significant disturbance of the beam (0.1% attenuation). MAPSs can be made very thin (~20 μm) with still a very good signal-to-noise performance. The VANILLA can reconstruct the collimated beam edge with approximately 64 μm precision.

  13. SU-E-T-377: Inaccurate Positioning Might Introduce Significant MapCheck Calibration Error in Flatten Filter Free Beams

    SciTech Connect

    Wang, S; Chao, C; Chang, J

    2014-06-01

    Purpose: This study investigates the calibration error of detector sensitivity for MapCheck due to inaccurate positioning of the device, which is not taken into account by the current commercial iterative calibration algorithm. We hypothesize the calibration is more vulnerable to the positioning error for the flatten filter free (FFF) beams than the conventional flatten filter flattened beams. Methods: MapCheck2 was calibrated with 10MV conventional and FFF beams, with careful alignment and with 1cm positioning error during calibration, respectively. Open fields of 37cmx37cm were delivered to gauge the impact of resultant calibration errors. The local calibration error was modeled as a detector independent multiplication factor, with which propagation error was estimated with positioning error from 1mm to 1cm. The calibrated sensitivities, without positioning error, were compared between the conventional and FFF beams to evaluate the dependence on the beam type. Results: The 1cm positioning error leads to 0.39% and 5.24% local calibration error in the conventional and FFF beams respectively. After propagating to the edges of MapCheck, the calibration errors become 6.5% and 57.7%, respectively. The propagation error increases almost linearly with respect to the positioning error. The difference of sensitivities between the conventional and FFF beams was small (0.11 ± 0.49%). Conclusion: The results demonstrate that the positioning error is not handled by the current commercial calibration algorithm of MapCheck. Particularly, the calibration errors for the FFF beams are ~9 times greater than those for the conventional beams with identical positioning error, and a small 1mm positioning error might lead to up to 8% calibration error. Since the sensitivities are only slightly dependent of the beam type and the conventional beam is less affected by the positioning error, it is advisable to cross-check the sensitivities between the conventional and FFF beams to detect

  14. Monitoring and controlling distributed applications using Lomita (position paper)

    NASA Technical Reports Server (NTRS)

    Marzullo, Keith; Szafranska, Ida M.

    1992-01-01

    Over the last four years, the Meta toolkit was developed for controlling distributed applications. This toolkit has been publicly available as part of the academic ISIS release, and has been used for building various system monitoring and control applications. One major stumbling block with using Meta has been the language (called NPL) it supports. NPL is very low-level and using it is difficult, in the same way it is difficult to write machine language programs or raw Postscript programs. Hence, a higher level language was built along with a runtime environment. The hope is that with this higher-level approach, more complicated Meta applications will be written and thereby concentrate more on the use (and limitations) of Meta as an architecture. The Meta toolkit is reviewed with its intended use. Next, the goals with Lomita and an overview is given of its architecture and language syntax. A detailed example is given of Lomita's use by presenting a complete program for a load-adaptable service.

  15. Monitor backscatter factors for the Varian 21EX and TrueBeam linear accelerators: measurements and Monte Carlo modelling.

    PubMed

    Zavgorodni, Sergei; Alhakeem, Eyad; Townson, Reid

    2014-02-21

    Linac backscattered radiation (BSR) into the monitor chamber affects the chamber's signal and has to be accounted for in radiotherapy dose calculations. In Monte Carlo (MC) calculations, the BSR can be modelled explicitly and accounted for in absolute dose. However, explicit modelling of the BSR becomes impossible if treatment head geometry is not available. In this study, monitor backscatter factors (MBSFs), defined as the ratio of the charge collected in the monitor chamber for a reference field to that of a given field, have been evaluated experimentally and incorporated into MC modelling of linacs with either known or unknown treatment head geometry. A telescopic technique similar to that by Kubo (1989 Med. Phys. 16 295-98) was used. However, instead of lead slits, a 1.8 mm diameter collimator and a small (2 mm diameter) detector positioned at extended source to detector distance were used. This setup provided a field of view to the source of less than 3.1 mm and allowed for MBSF measurements of open fields from 1 × 1 to 40 × 40 cm(2). For the fields with both X and Y dimensions exceeding 15 cm, a diode detector was used. A pinpoint ionization chamber was used for smaller fields. MBSFs were also explicitly modelled in MC calculations using BEAMnrc and DOSXYZnrc codes for 6 and 18 MV beams of a Varian 21EX linac. A method for deriving the D(ch)(forward) values that are used in MC absolute dose calculations was demonstrated. These values were derived from measured MBSFs for two 21EX and four TrueBeam energies. MBSFs were measured for 6 and 18 MV beams from Varian 21EX, and for 6 MV, 10 MV-FFF, 10 MV, and 15 MV beams from Varian TrueBeam linacs. For the open field sizes modelled in this study for the 21EX, the measured MBSFs agreed with MC calculated values within combined statistical (0.4%) and experimental (0.2%) uncertainties. Variation of MBSFs across field sizes was about a factor of two smaller for the TrueBeam compared to 21EX Varian linacs. Measured

  16. Monitor backscatter factors for the Varian 21EX and TrueBeam linear accelerators: measurements and Monte Carlo modelling

    NASA Astrophysics Data System (ADS)

    Zavgorodni, Sergei; Alhakeem, Eyad; Townson, Reid

    2014-02-01

    Linac backscattered radiation (BSR) into the monitor chamber affects the chamber's signal and has to be accounted for in radiotherapy dose calculations. In Monte Carlo (MC) calculations, the BSR can be modelled explicitly and accounted for in absolute dose. However, explicit modelling of the BSR becomes impossible if treatment head geometry is not available. In this study, monitor backscatter factors (MBSFs), defined as the ratio of the charge collected in the monitor chamber for a reference field to that of a given field, have been evaluated experimentally and incorporated into MC modelling of linacs with either known or unknown treatment head geometry. A telescopic technique similar to that by Kubo (1989 Med. Phys. 16 295-98) was used. However, instead of lead slits, a 1.8 mm diameter collimator and a small (2 mm diameter) detector positioned at extended source to detector distance were used. This setup provided a field of view to the source of less than 3.1 mm and allowed for MBSF measurements of open fields from 1 × 1 to 40 × 40 cm2. For the fields with both X and Y dimensions exceeding 15 cm, a diode detector was used. A pinpoint ionization chamber was used for smaller fields. MBSFs were also explicitly modelled in MC calculations using BEAMnrc and DOSXYZnrc codes for 6 and 18 MV beams of a Varian 21EX linac. A method for deriving the D_ch^forward values that are used in MC absolute dose calculations was demonstrated. These values were derived from measured MBSFs for two 21EX and four TrueBeam energies. MBSFs were measured for 6 and 18 MV beams from Varian 21EX, and for 6 MV, 10 MV-FFF, 10 MV, and 15 MV beams from Varian TrueBeam linacs. For the open field sizes modelled in this study for the 21EX, the measured MBSFs agreed with MC calculated values within combined statistical (0.4%) and experimental (0.2%) uncertainties. Variation of MBSFs across field sizes was about a factor of two smaller for the TrueBeam compared to 21EX Varian linacs. Measured MBSFs

  17. BEAM LIFETIME AND EMITTANCE GROWTH MEASUREMENTS OF GOLD BEAMS IN RHIC AT STORAGE.

    SciTech Connect

    FISCHER,W.; DREES,A.; BRENNAN,J.M.; CONNOLLY,R.; FLILLER,R.; TEPIKIAN,S.; VAN ZEIJTS,J.

    2001-06-18

    During stores of gold beams, longitudinal and transverse beam sizes were recorded. Longitudinal profiles were obtained with a wall current monitor. Transverse profiles were reconstructed from gold-gold collision rates at various relative transverse beam positions. The total beam lifetime was measured with a beam current transformer, the bunched beam lifetime with the wall current monitor. Diffusion rates in the beam halo were determined from the change in the loss rate when a scraper is retracted. The measurements are used to determine the lifetime limiting effects. Beam growth measurements are compared with computations of beam-growth times from intra-beam scattering.

  18. Small radio frequency driven multicusp ion source for positive hydrogen ion beam production

    SciTech Connect

    Perkins, L.T.; Herz, P.R.; Leung, K.N.; Pickard, D.S. )

    1994-04-01

    A compact, 2.5 cm diam rf-driven multicusp ion source has been developed and tested for H[sup +] ion production in pulse mode operation. The source is optimized for atomic hydrogen ion species and extractable current. It is found that hydrogen ion beam current densities in excess of 650 mA/cm[sup 2] can be achieved with H[sup +] species above 80%. The geometry and position of the porcelain-coated copper antenna were found to be of great significance in relation to the efficiency of the ion source.

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

    SciTech Connect

    Hao, Yue; Bai, Mei; Duan, Zhe; Luo, Yun; Marusic, Aljosa; Robert-Demolaize, Guillaume; Shen, Xiaozhe

    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.

  20. An etched fiber optic vibration sensor to monitor the simply supported beam

    NASA Astrophysics Data System (ADS)

    Putha, Kishore; Dinakar, Dantala; Rao, Pachava V.; Sengupta, Dipankar; Srimannarayana, K.; Sai Shankar, M.

    2012-04-01

    A single mode fiber optic vibration senor is designed and demonstrated to monitor the vibration of a simply supported beam. A rectangular beam (length 30.8 cm, width 2.5cm and thickness 0.5mm) made of spring-steel is arranged as simply supported beam and is made to vibrate periodically. To sense the vibrations a telecommunication fiber is chemically etched such that its diameter reaches 50μm and is glued using an epoxy at the centre of the beam. A broadband light (1550nm) is launched into Fiber Bragg Grating (FBG) through a circulator. The light reflected by the FBG (1540.32nm) is coupled into the centre etched fibre through the circulator and is detected by photodiode connected to a transimpedance amplifier. The electrical signal is logged into the computer through NI-6016 DAQ. The sensor works on transmission power loss due to the mode volume mismatch and flexural strain (field strength) of the fiber due to the bending in the fiber with respect to the bending of the spring-steel beam. The beam is made to vibrate and the corresponding intensity of light is recorded. Fast Fourier transform (FFT) technique is used to measure the frequencies of vibration. The results show that this sensor can sense vibration of low frequency accurately and repeatability is high. The sensor has high linear response to axial displacement of about 0.8 mm with sensitivity of 32mV/10μm strain. This lowcost sensor may find a place in industry to monitor the vibrations of the beam structures and bridges.

  1. A study of beam position diagnostics using beam-excited dipole modes in third harmonic superconducting accelerating cavities at a free-electron laser.

    PubMed

    Zhang, Pei; Baboi, Nicoleta; Jones, Roger M; Shinton, Ian R R; Flisgen, Thomas; Glock, Hans-Walter

    2012-08-01

    We investigate the feasibility of beam position diagnostics using higher order mode (HOM) signals excited by an electron beam in the third harmonic 3.9 GHz superconducting accelerating cavities at FLASH. After careful theoretical and experimental assessment of the HOM spectrum, three modal choices have been narrowed down to fulfill different diagnostics requirements. These are localized dipole beam-pipe modes, trapped cavity modes from the fifth dipole band, and propagating modes from the first two dipole bands. These modes are treated with various data analysis techniques: modal identification, direct linear regression (DLR), and singular value decomposition (SVD). Promising options for beam diagnostics are found from all three modal choices. This constitutes the first prediction, subsequently confirmed by experiments, of trapped HOMs in third harmonic cavities, and also the first direct comparison of DLR and SVD in the analysis of HOM-based beam diagnostics.

  2. A study of beam position diagnostics using beam-excited dipole modes in third harmonic superconducting accelerating cavities at a free-electron laser

    SciTech Connect

    Zhang Pei; Baboi, Nicoleta; Jones, Roger M.; Shinton, Ian R. R.; Flisgen, Thomas; Glock, Hans-Walter

    2012-08-15

    We investigate the feasibility of beam position diagnostics using higher order mode (HOM) signals excited by an electron beam in the third harmonic 3.9 GHz superconducting accelerating cavities at FLASH. After careful theoretical and experimental assessment of the HOM spectrum, three modal choices have been narrowed down to fulfill different diagnostics requirements. These are localized dipole beam-pipe modes, trapped cavity modes from the fifth dipole band, and propagating modes from the first two dipole bands. These modes are treated with various data analysis techniques: modal identification, direct linear regression (DLR), and singular value decomposition (SVD). Promising options for beam diagnostics are found from all three modal choices. This constitutes the first prediction, subsequently confirmed by experiments, of trapped HOMs in third harmonic cavities, and also the first direct comparison of DLR and SVD in the analysis of HOM-based beam diagnostics.

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

    NASA Astrophysics Data System (ADS)

    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.

  4. A plastic scintillating fiber position detector in vacuum for the test beam facility at BEPC II -LINAC

    NASA Astrophysics Data System (ADS)

    Ke, Zun-Jian; Li, Jia-Cai; Zhang, Shao-Ping; An, Guang-Peng; Tang, Xing-Hua; Yang, Tao

    2012-01-01

    Two plastic scintillating fiber position detectors for charged particles have been designed, built and installed inside the vacuum tube near two sides of the DM2 deflection magnet on the E3 beam line of the test beam facility at the BEPC-LINAC. A one-dimensional position resolution of ~1 mm with a sensitive area of 60 mm×60 mm has been obtained for this detector.

  5. LUMINESCENCE BEAM PROFILE MONITOR FOR THE RHIC POLARIZED HYDROGEN JET POLARIMETER.

    SciTech Connect

    LUCIANO, N.; NASS, A.; MAKDISI, Y.; THIEBERGER, P.; TRBOJEVIC, D.; ZELENSKI, A.

    2005-05-16

    A new polarized hydrogen jet target was used to provide improved beam polarization measurements during the second polarized proton m in the Relativistic Heavy Ion Collider (RHIC). The luminescence produced by beam-hydrogen excitations was also used to test the feasibility of a new beam profile monitor for RFPIC based on the detection of the emitted light. Lenses, a view-port and a sensitive CCD camera were added to the system to record the optical signals from the interaction chamber. The first very promising results are reported here. The same system with an additional optical spectrometer or optical filter system may be used in the future to detect impurities in the jet, such as oxygen molecules, which affect the accuracy of the polarization measurements.

  6. PRELIMINARY DESIGN OF THE BEAM LOSS MONITORING SYSTEM FOR THE SNS.

    SciTech Connect

    WITKOVER,R.; GASSNER,D.

    2002-05-06

    The SNS to be built at Oak Ridge National Laboratory will provide a high average intensity 1 GeV beam to produce spallation neutrons. Loss of a even small percentage of this intense beam would result in high radiation. The Beam Loss Monitor (ELM) system must detect such small, long term losses yet be capable of measuring infrequent short high losses. The large dynamic range presents special problems for the system design. Ion chambers will be used as the detectors. A detector originally designed for the FNAL Tevatron, was considered but concerns about ion collection times and low collection efficiency at high loss rates favor a new design. The requirements and design concepts of the proposed approach will be presented. Discussion of the design and testing of the ion chambers and the analog j-Point end electronics will be presented. The overall system design will be described.

  7. Beam-based monitoring of the SLC linac optics with a diagnostic pulse

    SciTech Connect

    Assmann, R.W.; Decker, F.J.; Hendrickson, L.J.; Phinney, N.; Siemann, R.H.; Underwood, K.K.; Woodley, M.

    1997-07-01

    The beam optics in a linear accelerator may be changed significantly by variations in the energy and energy spread profile along the linac. In particular, diurnal temperature swings in the SLC klystron gallery perturb the phase and amplitude of the accelerating RF fields. If such changes are not correctly characterized, the resulting errors will cause phase advance differences in the beam optics. In addition RF phase errors also affect the amplitude growth of betatron oscillations. The authors present an automated, simple procedure to monitor the beam optics in the SLC linac routinely and non-invasively. The measured phase advance and oscillation amplitude is shown as a function of time and is compared to the nominal optics.

  8. Evaluation test of the energy monitoring device in industrial electron beam facilities

    NASA Astrophysics Data System (ADS)

    Fuochi, P. G.; Lavalle, M.; Martelli, A.; Corda, U.; Cornia, G.; Kovács, A.

    2009-07-01

    The electron beam energy monitoring device, previously developed and tested under standard laboratory conditions using electron beams in the energy range 4-12 MeV, has now been tested under industrial irradiation conditions in high-energy, high-power electron beam facilities. The measuring instrument was improved in order to measure high peak current delivered at low pulse repetition rate as well. Tests, with good results, were carried out at two different EB plants: one equipped with a LUE-8 linear electron accelerator of 7 MeV maximum energy used for cross-linking of cables and for medical device sterilization, and the other with a 10 MeV Rhodotron type TT 100 used for in-house sterilization.

  9. Design, development, and operation of a fiber-based Cherenkov beam loss monitor at the SPring-8 Angstrom Compact Free Electron Laser

    NASA Astrophysics Data System (ADS)

    Maréchal, X.-M.; Asano, Y.; Itoga, T.

    2012-05-01

    A fiber-based Cherenkov beam loss monitor (CBLM) consisting of large core (400 μm), long (≥150 m) multimode fibers, has been developed as an online long-range detection tool with high sensitivity and good position resolution for the 8 GeV SPring-8 Angstrom Compact Free Electron Laser: primarily designed for radiation safety in order to limit the dose outside the shielding of the machine, this monitor also serves as an early warning tool to avoid radiation damages done by lost electrons to the undulator magnets. This paper presents the approach chosen to insure that the required sensitivity (≤1 pC) could be obtained over more than 100 m. A beam-based approach was used to characterize (attenuation and signal strength) different fibers (diameter, index profile, and numerical aperture) and to select the most appropriate one. The response of the detector has also been studied numerically for different geometries (vacuum pipe and in-vacuum type undulators), beam energies, and beam loss scenarios, to determine the optimum number of fibers and their position in order to achieve the required detection limit. The results of the first few months of operation show that the SPring-8 CBLM can detect beam losses of less than 0.5 pC over the full 150 m length of the fiber.

  10. Detection of bond failure in the anchorage zone of reinforced concrete beams via acoustic emission monitoring

    NASA Astrophysics Data System (ADS)

    Abouhussien, Ahmed A.; Hassan, Assem A. A.

    2016-07-01

    In this study, acoustic emission (AE) monitoring was utilised to identify the onset of bond failure in reinforced concrete beams. Beam anchorage specimens were designed and tested to fail in bond in the anchorage zone. The specimens included four 250 × 250 × 1500 mm beams with four variable bonded lengths (100, 200, 300, and 400 mm). Meanwhile, an additional 250 × 250 × 2440 mm beam, with 200 mm bonded length, was tested to investigate the influence of sensor location on the identification of bond damage. All beams were tested under four-point loading setup and continuously monitored using three distributed AE sensors. These attached sensors were exploited to record AE signals resulting from both cracking and bond deterioration until failure. The variations in the number of AE hits and cumulative signal strength (CSS) versus test time were evaluated to achieve early detection of crack growth and bar slippage. In addition, AE intensity analysis was performed on signal strength of collected AE signals to develop two additional parameters: historic index (H (t)) and severity (S r). The analysis of these AE parameters enabled an early detection of both first cracks (at almost the mid-span of the beam) and bar slip in either of the anchorage zones at the beams’ end before their visual observation, regardless of sensor location. The results also demonstrated a clear correlation between the damage level in terms of crack development/measured free end bar slip and AE parameters (number of hits, CSS, H(t), and S r).

  11. Group velocity delay spectroscopy technique for industrial monitoring of electron beam induced vapors

    SciTech Connect

    Benterou, J J; Berzins, L V; Sharma, M N

    1998-09-24

    Spectroscopic techniques are ideal for characterization and process control of electron beam generated vapor plumes. Absorption based techniques work well for a wide variety of applications, but are difficult to apply to optically dense or opaque vapor plumes. We describe an approach for monitoring optically dense vapor plumes that is based on measuring the group velocity delay of a laser beam near an optical transition to determine the vapor density. This technique has a larger dynamic range than absorption spectroscopy. We describe our progress towards a robust system to monitor aluminum vaporization in an industrial environment. Aluminum was chosen because of its prevalence in high performance aircraft alloys. In these applications, composition control of the alloy constituents is critical to the deposition process. Data is presented demonstrating the superior dynamic range of the measurement. In addition, preliminary data demonstrating aluminum vapor rate control in an electron beam evaporator is presented. Alternative applications where this technique could be useful are discussed. Keywords: Group velocity delay spectroscopy, optical beat signal, optical heterodyne, index of refraction, laser absorption spectroscopy, external cavity diode laser (ECDL), electron beam vaporization, vapor density, vapor phase manufacturing, process control

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

    SciTech Connect

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

    2004-11-10

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

  13. Measurements of the performance of a beam condition monitor prototype in a 5 GeV electron beam

    NASA Astrophysics Data System (ADS)

    Hempel, M.; Afanaciev, K.; Burtowy, P.; Dabrowski, A.; Henschel, H.; Idzik, M.; Karacheban, O.; Lange, W.; Leonard, J.; Levy, I.; Lohmann, W.; Pollak, B.; Przyborowski, D.; Ryjov, V.; Schuwalow, S.; Stickland, D.; Walsh, R.; Zagozdzinska, A.

    2016-08-01

    The Fast Beam Conditions Monitor, BCM1F, in the Compact Muon Solenoid, CMS, experiment was operated since 2008 and delivered invaluable information on the machine induced background in the inner part of the CMS detector supporting a safe operation of the inner tracker and high quality data. Due to the shortening of the time between two bunch crossings from 50 ns to 25 ns and higher expected luminosity at the Large Hadron Collider, LHC, in 2015, BCM1F needed an upgrade to higher bandwidth. In addition, BCM1F is used as an on-line luminometer operated independently of CMS. To match these requirements, the number of single crystal diamond sensors was enhanced from 8 to 24. Each sensor is subdivided into two pads, leading to 48 readout channels. Dedicated fast front-end ASICs were developed in 130 nm technology, and the back-end electronics is completely upgraded. An assembled prototype BCM1F detector comprising sensors, a fast front-end ASIC and optical analog readout was studied in a 5 GeV electron beam at the DESY-II accelerator. Results on the performance are given.

  14. Optical transition radiation from a thin carbon foil: a beam profile monitor for the SLC

    SciTech Connect

    Jenkins, E.W.

    1983-11-01

    This memo considers placement of an ultra thin carbon foil into the SLC beam. Transition radiation light would be emitted from the surface of the foil. The optical spot from the foil could be viewed with a microscope objective lens and registered with an image detector. Multiple scattering for the foil thicknesses necessary will not affect the beam emittance. Calculations show that a thin carbon foil can withstand the electron beam if the electron beam is larger than 10 ..mu..m in size. There are many possible radiation mechanisms from a foil - bremsstrahlung, black body temperature radiation, Cerenkov light, scintillation light, and transition radiation. Transition radiation is apparently dominant. It is proposed to use thin carbon foils, 75 to 150 A thick. Calculations indicate that 5 x 10/sup 10/ beam electrons will radiate a useable number of optical photons. Specifically with 150 A foils the fractional yield of useful optical photons is 10/sup -3/ photons per incident electron 5 x 10/sup +7/ optical photons imaged upon an image plane. Spread these photons over a 32 x 32 pixel CCD and one has the readout system of a monitor.

  15. KEKB beam instrumentation systems

    NASA Astrophysics Data System (ADS)

    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.

  16. A procedure for calculation of monitor units for passively scattered proton radiotherapy beams

    SciTech Connect

    Sahoo, Narayan; Zhu, X. Ronald; Arjomandy, Bijan; Ciangaru, George; Lii, MingFwu; Amos, Richard; Wu, Richard; Gillin, Michael T.

    2008-11-15

    The purpose of this study is to validate a monitor unit (MU) calculation procedure for passively scattered proton therapy beams. The output dose per MU (d/MU) of a therapeutic radiation beam is traditionally calibrated under specific reference conditions. These conditions include beam energy, field size, suitable depth in water or water equivalent phantom in a low dose gradient region with known relative depth dose, and source to point of calibration distance. Treatment field settings usually differ from these reference conditions leading to a different d/MU that needs to be determined for delivering the prescribed dose. For passively scattered proton beams, the proton specific parameters, which need to be defined, are related to the energy, lateral scatterers, range modulating wheel, spread out Bragg peak (SOBP) width, thickness of any range shifter, the depth dose value relative to the normalization point in the SOBP, and scatter both from the range compensator and inhomogeneity in the patient. Following the custom for photons or electrons, a set of proton dosimetry factors, representing the changes in the d/MU relative to a reference condition, can be defined as the relative output factor (ROF), SOBP factor (SOBPF), range shifter factor (RSF), SOBP off-center factor (SOBPOCF), off-center ratio (OCR), inverse square factor (ISF), field size factor (FSF), and compensator and patient scatter factor (CPSF). The ROF, SOBPF, and RSF are the major contributors to the d/MU and were measured using an ion chamber in water tank during the clinical commissioning of each beam to create a dosimetry beam data table to be used for calculating the monitor units. The following simple formula is found to provide an independent method to determine the d/MU at the point of interest (POI) in the patient, namely, (d/MU)=ROF{center_dot}SOBPF{center_dot}RSF{center_dot}SOBPOCF{center_dot}OCR{center_dot}FSF{center_dot}ISF{center_dot}CPSF. The monitor units for delivering the intended dose

  17. Structural health monitoring MEMS sensors using elasticity-based beam vibrations

    NASA Astrophysics Data System (ADS)

    Plankis, Alivia

    The worsening problem of aging and deficient infrastructure in this nation and across the world has demonstrated the need for an improved system to monitor and maintain these structures. The field of structural health monitoring has grown in recent years to address this issue. The goal of this field is to continually monitor the condition of a structure to detect and mitigate damage that may occur. Many structural health monitoring methods have been developed and most of these require sensor systems to collect the necessary information to assess the current strength and integrity of a structure. The motivation for this thesis is a proposed new microelectromechanical systems (MEMS) sensor with applications in civil infrastructure sensing. The work required was to determine accurate estimates of the resonant frequencies for a fixed-fixed silicon bridge within the device so that further testing and development could proceed. Additional knowledge and information were essential, though, before these requested calculations could be performed confidently. First, a thorough review of current structural health monitoring concepts and methods was performed to better understand the field in which this device would be applied and what incentive existed to develop a new sensor. Second, an in-depth investigation of vibrational beam mechanics theories was completed to ensure the accuracy of the frequency results for the new MEMS sensor. This study analyzed the influence of three assumptions employed in the Euler-Bernoulli, Rayleigh, and Timoshenko beam theories by comparing their results to a three-dimensional, elasticity-based approximation for vibrational frequencies and mode shapes. The results of this study showed that all three theories are insufficient when a fixed support is involved, so the elasticity-based approximation was utilized to calculate the frequencies for the bridge component in the MEMS device. These results have been passed on to the developers so that the

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

    NASA Astrophysics Data System (ADS)

    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).

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

    NASA Astrophysics Data System (ADS)

    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.

  20. Performance of the Fast Beam Conditions Monitor BCM1F of CMS in the first running periods of LHC

    NASA Astrophysics Data System (ADS)

    Schmidt, R. S.; Bell, A. J.; Castro, E.; Hall-Wilton, R.; Hempel, M.; Lange, W.; Lohmann, W.; Müller, S.; Ryjov, V.; Stickland, D.; Walsh, R.

    2011-01-01

    The Beam Conditions and Radiation Monitoring System, BRM, is implemented in CMS to protect the detector and provide an interface to the LHC. Seven sub-systems monitor beam conditions and the radiation level inside the detector on different time scales. They detect adverse beam conditions, facilitate beam tuning close to CMS, and measure the doses accumulated in different detector components. Data are taken and analysed independently of the CMS data acquisition, displayed in the control room, and provide inputs to the trigger system and the LHC operators. In case of beam conditions dangerous to the CMS detector, a beam abort is induced. The Fast Beam Conditions Monitor, BCM1F, is a flux counter close to the beam pipe inside the tracker volume. It uses single-crystal CVD diamond sensors, radiation-hard FE electronics, and optical signal transmission to measure the beam halo as well as collision products bunch by bunch. The system has been operational during the initiatory runs of LHC in September 2008. It works reliably since the restart in 2009 and is invaluable to CMS for everyday LHC operation. A characterisation of the system on the basis of data collected during LHC operation is presented.

  1. High Accuracy Beam Current Monitor System for CEBAF'S Experimental Hall A

    SciTech Connect

    J. Denard; A. Saha; G. Lavessiere

    2001-07-01

    CEBAF accelerator delivers continuous wave (CW) electron beams to three experimental Halls. In Hall A, all experiments require continuous, non-invasive current measurements and a few experiments require an absolute accuracy of 0.2 % in the current range from 1 to 180 {micro}A. A Parametric Current Transformer (PCT), manufactured by Bergoz, has an accurate and stable sensitivity of 4 {micro}A/V but its offset drifts at the muA level over time preclude its direct use for continuous measurements. Two cavity monitors are calibrated against the PCT with at least 50 {micro}A of beam current. The calibration procedure suppresses the error due to PCT's offset drifts by turning the beam on and off, which is invasive to the experiment. One of the goals of the system is to minimize the calibration time without compromising the measurement's accuracy. The linearity of the cavity monitors is a critical parameter for transferring the accurate calibration done at high currents over the whole dynamic range. The method for measuring accurately the linearity is described.

  2. Thin conductive diamond films as beam intensity monitors for soft x-ray beamlines.

    PubMed

    Kummer, K; Fondacaro, A; Yakhou-Harris, F; Sessi, V; Pobedinskas, P; Janssens, S D; Haenen, K; Williams, O A; Hees, J; Brookes, N B

    2013-03-01

    Quantitative analysis of X-ray absorption and dichroism data requires knowledge of the beamline photon flux during the measurements. We show that thin conductive (B-doped) diamond thin films can be an alternative to the widely used gold meshes for monitoring the beam intensity of soft X-ray beamlines in situ. Limited by the carbon extended x-ray absorption fine structure oscillations, the diamond films become applicable beginning from about 600 eV photon energy, where the important transition metal edges and the rare-earth edges are found. The 100 nm and 250 nm thick free-standing diamond films were grown and tested against standard gold meshes in real-life dichroism experiments performed at beamline ID08 of the European Synchrotron Radiation Facility, Grenoble, France. Quantitative agreement was found between the two experimental data sets. The films feature an extremely high transmission of about 90% and, at the same time, yield a sufficiently strong and clean reference signal. Furthermore, the thin films do not affect the shape of the transmitted beam. X-rays passing mesh-type monitors are subject to diffraction effects, which widen the beam and become particularly disturbing for small beamsizes in the micrometer range. PMID:23556850

  3. Thin conductive diamond films as beam intensity monitors for soft x-ray beamlines

    SciTech Connect

    Kummer, K.; Fondacaro, A.; Yakhou-Harris, F.; Sessi, V.; Brookes, N. B.; Pobedinskas, P.; Janssens, S. D.; Haenen, K.; Williams, O. A.; Hees, J.

    2013-03-15

    Quantitative analysis of X-ray absorption and dichroism data requires knowledge of the beamline photon flux during the measurements. We show that thin conductive (B-doped) diamond thin films can be an alternative to the widely used gold meshes for monitoring the beam intensity of soft X-ray beamlines in situ. Limited by the carbon extended x-ray absorption fine structure oscillations, the diamond films become applicable beginning from about 600 eV photon energy, where the important transition metal edges and the rare-earth edges are found. The 100 nm and 250 nm thick free-standing diamond films were grown and tested against standard gold meshes in real-life dichroism experiments performed at beamline ID08 of the European Synchrotron Radiation Facility, Grenoble, France. Quantitative agreement was found between the two experimental data sets. The films feature an extremely high transmission of about 90% and, at the same time, yield a sufficiently strong and clean reference signal. Furthermore, the thin films do not affect the shape of the transmitted beam. X-rays passing mesh-type monitors are subject to diffraction effects, which widen the beam and become particularly disturbing for small beamsizes in the micrometer range.

  4. A novel Beam Halo Monitor for the CMS experiment at the LHC

    NASA Astrophysics Data System (ADS)

    Orfanelli, S.; Dabrowski, A. E.; Giunta, M.; Loos, R.; Ambrose, M. J.; Mans, J.; Rusack, R.; Stifter, K.; Stickland, D.; Fabbri, F.; Manna, A.; Montanari, A.; Tosi, N.; Calvelli, V.

    2015-11-01

    A novel Beam Halo Monitor (BHM) has been designed and built for the CMS experiment at the LHC. It will provide an online, bunch-by-bunch measurement of background particles created by interactions of the proton beam with residual gas molecules in the vacuum chamber or with collimator material upstream of CMS. The BHM consists of two arrays of twenty detectors that are mounted around the outer forward shielding of the CMS experiment. Each detector is comprised of a cylindrical quartz radiator, optically coupled to a fast ultraviolet-sensitive photomultiplier tube from one end and painted black at the opposite end. Particles moving towards the photomultiplier tube will be detected with time resolution of a few nanoseconds, allowing to measure the flux of background particles produced upstream of CMS and suppress signals from collision-induced products. Monte Carlo simulations were performed to optimise the detector design. Prior to installation, the performance of the prototype detectors was measured in test beams quantifying the detector's direction-sensitive response and time resolution. The BHM was installed during the first LHC long shutdown (LS1) and is currently being commissioned. Design considerations, results from the test-beams supporting the design and the installation of the BHM in the CMS are presented.

  5. Displacement sensing based on resonant frequency monitoring of electrostatically actuated curved micro beams

    NASA Astrophysics Data System (ADS)

    Krakover, Naftaly; Ilic, B. Robert; Krylov, Slava

    2016-11-01

    The ability to control nonlinear interactions of suspended mechanical structures offers a unique opportunity to engineer rich dynamical behavior that extends the dynamic range and ultimate device sensitivity. We demonstrate a displacement sensing technique based on resonant frequency monitoring of curved, doubly clamped, bistable micromechanical beams interacting with a movable electrode. In this configuration, the electrode displacement influences the nonlinear electrostatic interactions, effective stiffness and frequency of the curved beam. Increased sensitivity is made possible by dynamically operating the beam near the snap-through bistability onset. Various in-plane device architectures were fabricated from single crystal silicon and measured under ambient conditions using laser Doppler vibrometry. In agreement with the reduced order Galerkin-based model predictions, our experimental results show a significant resonant frequency reduction near critical snap-through, followed by a frequency increase within the post-buckling configuration. Interactions with a stationary electrode yield a voltage sensitivity up to  ≈560 Hz V‑1 and results with a movable electrode allow motion sensitivity up to  ≈1.5 Hz nm‑1. Our theoretical and experimental results collectively reveal the potential of displacement sensing using nonlinear interactions of geometrically curved beams near instabilities, with possible applications ranging from highly sensitive resonant inertial detectors to complex optomechanical platforms providing an interface between the classical and quantum domains.

  6. Test results on the silicon pixel detector for the TTF-FEL beam trajectory monitor

    NASA Astrophysics Data System (ADS)

    Hillert, S.; Ischebeck, R.; Müller, U. C.; Roth, S.; Hansen, K.; Holl, P.; Karstensen, S.; Kemmer, J.; Klanner, R.; Lechner, P.; Leenen, M.; Ng, J. S. T.; Schmüser, P.; Strüder, L.

    2001-02-01

    Test measurements on the silicon pixel detector for the beam trajectory monitor at the free-electron laser of the TESLA test facility are presented. To determine the electronic noise of the detector and the read-out electronics and to calibrate the signal amplitude of different pixels, the 6 keV photons of the manganese K α/K β line are used. Two different methods determine the spatial accuracy of the detector: in one setup a laser beam is focused to a straight line and moves across the pixel structure. In the other, the detector is scanned using a low-intensity electron beam of an electron microscope. Both methods show that the symmetry axis of the detector defines a straight line within 0.4 μm. The sensitivity of the detector to low-energy X-rays is measured using a vacuum ultraviolet beam at the synchrotron light source HASYLAB. Additionally, the electron microscope is used to study the radiation hardness of the detector.

  7. Precise voltage contrast image assisted positioning for in situ electron beam nanolithography for nanodevice fabrication with suspended nanowire structures

    NASA Astrophysics Data System (ADS)

    Long, Renhai; Chen, Jiajun; Lim, Jin-Hee; Wiley, John B.; Zhou, Weilie

    2009-07-01

    In this paper, we demonstrate precise voltage contrast image positioning for in situ electron beam (e-beam) nanolithography to integrate nanowires into suspended structures for nanoswitch fabrication. The positioning of the deflection electrodes on the nanowires can be well controlled using a precise voltage contrast image positioning technique, where the error can be minimized to about 10 nm. Using such a method, dispersed nanowires can be sandwiched between two layers of resist and suspended by one e-beam nanolithography process without any etching. The in situ e-beam nanolithography eliminates the stage movement error by preventing any movements of the stage during the nanolithography process; hence, a high precision laser stage and alignment marks on the substrate are not needed, which simplifies the traditional e-beam nanolithography process. The nanoswitches fabricated using this method show ON and OFF states with the changes of applied voltages. This simplified process provides an easy, low cost and less time-consuming route to integrating suspended nanowire based structures using a converted field emission scanning electron microscope e-beam system, which can also be customized to fabricate multi-layer structures and a site-specific nanodevice fabrication.

  8. Relative position determination of a lunar rover using the biased differential phase delay of same-beam VLBI

    NASA Astrophysics Data System (ADS)

    Chen, Ming; Liu, Qinghui; Wu, Yajun; Zhao, Rongbing; Dai, Zhiqiang

    2011-12-01

    When only data transmission signals with a bandwidth of 1 MHz exist in the rover, the position can be obtained using the differential group delay data of the same-beam very long baseline interferometry (VLBI). The relative position between a lunar rover and a lander can be determined with an error of several hundreds of meters. When the guidance information of the rover is used to determine relative position, the rover's wheel skid behavior and integral movement may influence the accuracy of the determined position. This paper proposes a new method for accurately determining relative position. The differential group delay and biased differential phase delay are obtained from the same-beam VLBI observation, while the modified biased differential phase delay is obtained using the statistic mean value of the differential group delay and the biased phase delay as basis. The small bias in the modified biased phase delay is estimated together with other parameters when the relative position of the rover is calculated. The effectiveness of the proposed method is confirmed using the same-beam VLBI observation data of SELENE. The radio sources onboard the rover and the lander are designed for same-beam VLBI observations. The results of the simulations of the differential delay of the same-beam VLBI observation between the rover and the lander show that the differential delay is sensitive to relative position. An approach to solving the relative position and a strategy for tracking are also introduced. When the lunar topography data near the rover are used and the observations are scheduled properly, the determined relative position of the rover may be nearly as accurate as that solved using differential phase delay data.

  9. Diffuse ultrasound monitoring of stress and damage development on a 15-ton concrete beam.

    PubMed

    Zhang, Yuxiang; Planès, Thomas; Larose, Eric; Obermann, Anne; Rospars, Claude; Moreau, Gautier

    2016-04-01

    This paper describes the use of an ultrasonic imaging technique (Locadiff) for the Non-Destructive Testing & Evaluation of a concrete structure. By combining coda wave interferometry and a sensitivity kernel for diffuse waves, Locadiff can monitor the elastic and structural properties of a heterogeneous material with a high sensitivity, and can map changes of these properties over time when a perturbation occurs in the bulk of the material. The applicability of the technique to life-size concrete structures is demonstrated through the monitoring of a 15-ton reinforced concrete beam subject to a four-point bending test causing cracking. The experimental results show that Locadiff achieved to (1) detect and locate the cracking zones in the core of the concrete beam at an early stage by mapping the changes in the concrete's micro-structure; (2) monitor the internal stress level in both temporal and spatial domains by mapping the variation in velocity caused by the acousto-elastic effect. The mechanical behavior of the concrete structure is also studied using conventional techniques such as acoustic emission, vibrating wire extensometers, and digital image correlation. The performances of the Locadiff technique in the detection of early stage cracking are assessed and discussed. PMID:27106315

  10. Diffuse ultrasound monitoring of stress and damage development on a 15-ton concrete beam.

    PubMed

    Zhang, Yuxiang; Planès, Thomas; Larose, Eric; Obermann, Anne; Rospars, Claude; Moreau, Gautier

    2016-04-01

    This paper describes the use of an ultrasonic imaging technique (Locadiff) for the Non-Destructive Testing & Evaluation of a concrete structure. By combining coda wave interferometry and a sensitivity kernel for diffuse waves, Locadiff can monitor the elastic and structural properties of a heterogeneous material with a high sensitivity, and can map changes of these properties over time when a perturbation occurs in the bulk of the material. The applicability of the technique to life-size concrete structures is demonstrated through the monitoring of a 15-ton reinforced concrete beam subject to a four-point bending test causing cracking. The experimental results show that Locadiff achieved to (1) detect and locate the cracking zones in the core of the concrete beam at an early stage by mapping the changes in the concrete's micro-structure; (2) monitor the internal stress level in both temporal and spatial domains by mapping the variation in velocity caused by the acousto-elastic effect. The mechanical behavior of the concrete structure is also studied using conventional techniques such as acoustic emission, vibrating wire extensometers, and digital image correlation. The performances of the Locadiff technique in the detection of early stage cracking are assessed and discussed.

  11. Calibration and performance of a secondary emission chamber as a beam intensity monitor

    SciTech Connect

    Sivertz, M.; Chiang, I-H,; Rusek, A.

    2011-03-28

    We report on a study of the behavior of a secondary emission chamber (SEC). We show the dependence of the SEC signal on the charge and velocity of the primary beam for beams of protons, and heavy ions including Helium, Neon, Chlorine and Iron. We fill the SEC with a selection of different gases including Hydrogen, Helium, Nitrogen, Argon, and air, studying the SEC response when it is acting as an ion chamber. We also investigate the behavior of the SEC at intermediate pressures between 10{sup -8} torr and atmospheric pressure. The SEC uses thin conducting foils as the source and collector of electrons in a vacuum chamber. When charged particles traverse the vacuum chamber, they pass through a series of thin conducting foils, alternating anode and cathode. Ionization produced in the cathode foils travels across the intervening gap due to an applied high voltage and is collected on the anode foils. Electron production is very inefficient because most of the ionization in the foils remains trapped within the foil due to the short range of most delta-rays and the work function of the foil. It is this inefficiency that allows the SEC to operate at high dose rates and short pulse duration where the standard ion chambers cannot function reliably. The SEC was placed in the NSRL ion beam to receive a variety of heavy ion beams under different beam conditions. We used these ion beams to study the response of the SEC to different species of heavy ion, comparing with proton beams. We studied the response to beam of different energies, and as a function of different counting rate. We compared the behaviour of the SEC when operating under positive and negative high voltage. The SEC can operate as an ion chamber if it is filled with gas. We measured the response of the SEC when filled with a variety of gases, from Hydrogen to Helium, Nitrogen, Argon and air. The performance of the SEC as an ion chamber is compared with the standard NSRL ion chamber, QC3. By evacuating the SEC and

  12. TH-C-BRD-03: Determining the Optimal Collimator Position for Collimated Pencil Beam Scanning Proton Therapy

    SciTech Connect

    Wang, D; Smith, B; Hill, P; Gelover, E; Flynn, R; Hyer, D

    2014-06-15

    Purpose: There has been a growing interest in applying collimation to pencil beam scanning (PBS) proton therapy in order to sharpen the lateral dose falloff out of the target, especially at low energies. Currently, there is not a method to optimally determine the collimation position or margin around the target. A uniform margin would not be ideal due to the fact that an incoming symmetric pencil beam, after being intercepted by a collimator near the target boundary, will become asymmetric and experience a lateral shift away from its original spot location, leaving the target insufficiently covered. We demonstrate a method that optimally determines the collimator position on a per-spot basis, in order to maximize target dose while minimizing normal tissue dose. Methods: A library of collimated pencil beams were obtained through Monte Carlo simulation with a collimator placed at varying distances from the central axis of an incoming symmetrical pencil beam of 118 MeV and 5 mm sigma-in-air. Two-dimensional treatment plans were then created using this library of collimated pencil beams. For each spot position in a treatment plan, the collimator position was optimally determined in such a way that the resultant pencil beam maximized the ratio of in-target dose and out-of-target dose. For comparison, un-collimated treatment plans were also computed. Results: The spot-by-spot optimally determined collimator positions allowed the reduction of normal tissue dose while maintaining the same target coverage as un-collimated PBS. Quantitatively, the mean dose outside of the target was reduced by approximately 40% as compared to the plan without collimation. Conclusion: The proposed method determines the optimal collimator position for each spot in collimated PBS proton therapy. The use of a collimator will improve PBS dose distributions achievable today and will continue to be the subject of future investigations.

  13. Characterization and performances of a monitoring ionization chamber dedicated to IBA-universal irradiation head for Pencil Beam Scanning

    NASA Astrophysics Data System (ADS)

    Courtois, C.; Boissonnat, G.; Brusasco, C.; Colin, J.; Cussol, D.; Fontbonne, J. M.; Marchand, B.; Mertens, T.; de Neuter, S.; Peronnel, J.

    2014-02-01

    Every radiotherapy center has to be equipped with real-time beam monitoring devices. In 2008, we developed an ionization chamber in collaboration with the IBA (Ion Beam Applications) company. This monitoring device called IC2/3 was developed to be used in IBA universal irradiation head for Pencil Beam Scanning (PBS). Here we present the characterization of the IC2/3 monitor in the energy and flux ranges used in protontherapy. The equipment has been tested with an IBA cyclotron able to deliver proton beams from 70 to 230 MeV. This beam monitoring device has been validated and is now installed at the Westdeutsches Protonentherapiezentrum Essen protontherapy center (WPE, Germany). The results obtained in both terms of spatial resolution and dose measurements are at least equal to the initial specifications needed for PBS purposes. The detector measures the dose with a relative uncertainty lower than 1% in the range from 0.5 Gy/min to 8 Gy/min while the spatial resolution is better than 250 μm. The technology has been patented and five IC2/3 chambers were delivered to IBA. Nowadays, IBA produces the IC2/3 beam monitoring device as a part of its Proteus 235 product.

  14. Intelligent low-level RF system by non-destructive beam monitoring device for cyclotrons

    NASA Astrophysics Data System (ADS)

    Sharifi Asadi Malafeh, M. S.; Ghergherehchi, M.; Afarideh, H.; Chai, J. S.; Yoon, Sang Kim

    2016-04-01

    The project of a 10 MeV PET cyclotron accelerator for medical diagnosis and treatment was started at Amirkabir University of Technology in 2012. The low-level RF system of the cyclotron accelerator is designed to stabilize acceleration voltage and control the resonance frequency of the cavity. In this work an Intelligent Low Level Radio Frequency Circuit or ILLRF, suitable for most AVF cyclotron accelerators, is designed using a beam monitoring device and narrow band tunable band-pass filter. In this design, the RF phase detection does not need signal processing by a microcontroller.

  15. Reflection mass spectrometry technique for monitoring and controlling composition during molecular beam epitaxy

    DOEpatents

    Brennan, Thomas M.; Hammons, B. Eugene; Tsao, Jeffrey Y.

    1992-01-01

    A method for on-line accurate monitoring and precise control of molecular beam epitaxial growth of Groups III-III-V or Groups III-V-V layers in an advanced semiconductor device incorporates reflection mass spectrometry. The reflection mass spectrometry is responsive to intentional perturbations in molecular fluxes incident on a substrate by accurately measuring the molecular fluxes reflected from the substrate. The reflected flux is extremely sensitive to the state of the growing surface and the measurements obtained enable control of newly forming surfaces that are dynamically changing as a result of growth.

  16. Reflection mass spectrometry technique for monitoring and controlling composition during molecular beam epitaxy

    DOEpatents

    Brennan, T.M.; Hammons, B.E.; Tsao, J.Y.

    1992-12-15

    A method for on-line accurate monitoring and precise control of molecular beam epitaxial growth of Groups III-III-V or Groups III-V-V layers in an advanced semiconductor device incorporates reflection mass spectrometry. The reflection mass spectrometry is responsive to intentional perturbations in molecular fluxes incident on a substrate by accurately measuring the molecular fluxes reflected from the substrate. The reflected flux is extremely sensitive to the state of the growing surface and the measurements obtained enable control of newly forming surfaces that are dynamically changing as a result of growth. 3 figs.

  17. Monitoring positive mental health and its determinants in Canada: the development of the Positive Mental Health Surveillance Indicator Framework

    PubMed Central

    Orpana, H.; Vachon, J.; Dykxhoorn, J.; McRae, L.; Jayaraman, G.

    2016-01-01

    Abstract Introduction: The Mental Health Strategy for Canada identified a need to enhance the collection of data on mental health in Canada. While surveillance systems on mental illness have been established, a data gap for monitoring positive mental health and its determinants was identified. The goal of this project was to develop a Positive Mental Health Surveillance Indicator Framework, to provide a picture of the state of positive mental health and its determinants in Canada. Data from this surveillance framework will be used to inform programs and policies to improve the mental health of Canadians. Methods: A literature review and environmental scan were conducted to provide the theoretical base for the framework, and to identify potential positive mental health outcomes and risk and protective factors. The Public Health Agency of Canada’s definition of positive mental health was adopted as the conceptual basis for the outcomes of this framework. After identifying a comprehensive list of risk and protective factors, mental health experts, other governmental partners and non-governmental stakeholders were consulted to prioritize these indicators. Subsequently, these groups were consulted to identify the most promising measurement approaches for each indicator. Results: A conceptual framework for surveillance of positive mental health and its determinants has been developed to contain 5 outcome indicators and 25 determinant indicators organized within 4 domains at the individual, family, community and societal level. This indicator framework addresses a data gap identified in Canada’s strategy for mental health and will be used to inform programs and policies to improve the mental health status of Canadians throughout the life course. PMID:26789022

  18. Monitoring daily MLC positional errors using trajectory log files and EPID measurements for IMRT and VMAT deliveries.

    PubMed

    Agnew, A; Agnew, C E; Grattan, M W D; Hounsell, A R; McGarry, C K

    2014-05-01

    This work investigated the differences between multileaf collimator (MLC) positioning accuracy determined using either log files or electronic portal imaging devices (EPID) and then assessed the possibility of reducing patient specific quality control (QC) via phantom-less methodologies. In-house software was developed, and validated, to track MLC positional accuracy with the rotational and static gantry picket fence tests using an integrated electronic portal image. This software was used to monitor MLC daily performance over a 1 year period for two Varian TrueBeam linear accelerators, with the results directly compared with MLC positions determined using leaf trajectory log files. This software was validated by introducing known shifts and collimator errors. Skewness of the MLCs was found to be 0.03 ± 0.06° (mean ±1 standard deviation (SD)) and was dependent on whether the collimator was rotated manually or automatically. Trajectory log files, analysed using in-house software, showed average MLC positioning errors with a magnitude of 0.004 ± 0.003 mm (rotational) and 0.004 ± 0.011 mm (static) across two TrueBeam units over 1 year (mean ±1 SD). These ranges, as indicated by the SD, were lower than the related average MLC positioning errors of 0.000 ± 0.025 mm (rotational) and 0.000 ± 0.039 mm (static) that were obtained using the in-house EPID based software. The range of EPID measured MLC positional errors was larger due to the inherent uncertainties of the procedure. Over the duration of the study, multiple MLC positional errors were detected using the EPID based software but these same errors were not detected using the trajectory log files. This work shows the importance of increasing linac specific QC when phantom-less methodologies, such as the use of log files, are used to reduce patient specific QC. Tolerances of 0.25 mm have been created for the MLC positional errors using the EPID-based automated picket fence test. The software allows

  19. Monitoring daily MLC positional errors using trajectory log files and EPID measurements for IMRT and VMAT deliveries

    NASA Astrophysics Data System (ADS)

    Agnew, A.; Agnew, C. E.; Grattan, M. W. D.; Hounsell, A. R.; McGarry, C. K.

    2014-05-01

    This work investigated the differences between multileaf collimator (MLC) positioning accuracy determined using either log files or electronic portal imaging devices (EPID) and then assessed the possibility of reducing patient specific quality control (QC) via phantom-less methodologies. In-house software was developed, and validated, to track MLC positional accuracy with the rotational and static gantry picket fence tests using an integrated electronic portal image. This software was used to monitor MLC daily performance over a 1 year period for two Varian TrueBeam linear accelerators, with the results directly compared with MLC positions determined using leaf trajectory log files. This software was validated by introducing known shifts and collimator errors. Skewness of the MLCs was found to be 0.03 ± 0.06° (mean ±1 standard deviation (SD)) and was dependent on whether the collimator was rotated manually or automatically. Trajectory log files, analysed using in-house software, showed average MLC positioning errors with a magnitude of 0.004 ± 0.003 mm (rotational) and 0.004 ± 0.011 mm (static) across two TrueBeam units over 1 year (mean ±1 SD). These ranges, as indicated by the SD, were lower than the related average MLC positioning errors of 0.000 ± 0.025 mm (rotational) and 0.000 ± 0.039 mm (static) that were obtained using the in-house EPID based software. The range of EPID measured MLC positional errors was larger due to the inherent uncertainties of the procedure. Over the duration of the study, multiple MLC positional errors were detected using the EPID based software but these same errors were not detected using the trajectory log files. This work shows the importance of increasing linac specific QC when phantom-less methodologies, such as the use of log files, are used to reduce patient specific QC. Tolerances of 0.25 mm have been created for the MLC positional errors using the EPID-based automated picket fence test. The software allows diagnosis

  20. Intrafractional prostate motion during external beam radiotherapy monitored by a real-time target localization system.

    PubMed

    Tong, Xu; Chen, Xiaoming; Li, Jinsheng; Xu, Qianqian; Lin, Mu-Han; Chen, Lili; Price, Robert A; Ma, Chang-Ming

    2015-03-08

    This paper investigates the clinical significance of real-time monitoring of intrafractional prostate motion during external beam radiotherapy using a commercial 4D localization system. Intrafractional prostate motion was tracked during 8,660 treatment fractions for 236 patients. The following statistics were analyzed: 1) the percentage of fractions in which the prostate shifted 2-7 mm for a certain duration; 2) the proportion of the entire tracking time during which the prostate shifted 2-7mm; and 3) the proportion of each minute in which the shift exceeded 2-7 mm. The ten patients exhibiting maximum intrafractional-motion patterns were analyzed separately. Our results showed that the percentage of fractions in which the prostate shifted by > 2, 3, 5, and 7 mm off the baseline in any direction for > 30 s was 56.8%, 27.2%, 4.6%, and 0.7% for intact prostate and 68.7%, 35.6%, 10.1%, and 1.8% for postprostatectomy patients, respectively. For the ten patients, these percentages were 91.3%, 72.4%, 36.3%, and 6%, respectively. The percentage of tracking time during which the prostate shifted > 2, 3, 5, and 7 mm was 27.8%, 10.7%, 1.6%, and 0.3%, respectively, and it was 56.2%, 33.7%, 11.2%, and 2.1%, respectively, for the ten patients. The percentage of tracking time for a > 3 mm posterior motion was four to five times higher than that in other directions. For treatments completed in 5 min (VMAT) and 10 min (IMRT), the proportion for the prostate to shift by > 3mm was 4% and 12%, respectively. Although intrafractional prostate motion was generally small, caution should be taken for patients who exhibit frequent large intrafractional motion. For those patients, adjustment of patient positioning may be necessary or a larger treatment margin may be used. After the initial alignment, the likelihood of prostate motion increases with time. Therefore, it is favorable to use advanced techniques (e.g., VMAT) that require less delivery time in order to reduce the treatment

  1. Individual Beam Size And Length Measurements at the SLC Interaction Point Derived From the Beam Energy Loss During a Beam Beam Deflection Scan

    SciTech Connect

    Raimondi, P.; Field, R.Clive; Phinney, N.; Ross, M.C.; Slaton, T.; Traller, R.; /SLAC

    2011-08-26

    At the Interaction Point (IP) of the SLC Final Focus, beam-beam deflection scans routinely provide a measurement of the sum in quadrature of the electron and positron transverse beam sizes, but no information on the individual beam sizes. During the 1996 SLC run, an upgrade to the Final Focus beam position monitor system allowed a first measurement of the absolute beam energy loss of both beams on each step of the deflection scan. A fit to the energy loss distributions of the two beams provides a measurement not only of the individual transverse beam sizes at the IP but also of the individual bunch lengths.

  2. Direct focusing error correction with ring-wide TBT beam position data

    SciTech Connect

    Yang, M.J.; /Fermilab

    2011-03-01

    Turn-By-Turn (TBT) betatron oscillation data is a very powerful tool in studying machine optics. Hundreds and thousands of turns of free oscillations are taken in just few tens of milliseconds. With beam covering all positions and angles at every location TBT data can be used to diagnose focusing errors almost instantly. This paper describes a new approach that observes focusing error collectively over all available TBT data to find the optimized quadrupole strength, one location at a time. Example will be shown and other issues will be discussed. The procedure presented clearly has helped to reduce overall deviations significantly, with relative ease. Sextupoles, being a permanent feature of the ring, will need to be incorporated into the model. While cumulative effect from all sextupoles around the ring may be negligible on turn-to-turn basis it is not so in this transfer line analysis. It should be noted that this procedure is not limited to looking for quadrupole errors. By modifying the target of minimization it could in principle be used to look for skew quadrupole errors and sextupole errors as well.

  3. Calculations of Auger intensity versus beam position for a sample with layers perpendicular to its surface

    NASA Astrophysics Data System (ADS)

    Zommer, L.; Jablonski, A.

    2010-07-01

    Recent advances in nanotechnology are a driving force for the improvement of lateral resolution in advanced analytical techniques such as scanning electron microscopy or scanning Auger microscopy (SAM). Special samples with multilayers which are perpendicular to their surface are presently proposed for testing the lateral resolution, as discussed in recent works of Senoner et al (2004 Surf. Interface Anal. 36 1423). The relevant experiment needs a theoretical description based on recent progress in the theory. Monte Carlo simulations of electron trajectories make possible an accurate description of the considered system. We selected exemplary samples, with layers perpendicular to the surface. The layer materials are elemental solids with high, medium and low atomic numbers, i.e. Au|Cu|Au and Au|Si|Au. For these systems calculations of the Auger current versus beam position were performed. We found that, for a system with layers consisting of elements of considerably different atomic numbers, the relation can have an unexpected extreme. This observation can be important in analysis of SAM pictures.

  4. Operational Performance of LCLS Beam Instrumentation

    SciTech Connect

    Loos, Henrik; Akre, R.; Brachmann, A.; Coffee, R.; Decker, F.-J.; Ding, Y.; Dowell, D.; Edstrom, S.; Emma, P.; Fisher, A.; Frisch, J.; Gilevich, S.; Hays, G.; Hering, Ph.; Huang, Z.; Iverson, R.; Messerschmidt, M.; Miahnahri, A.; Moeller, S.; Nuhn, H.-D.; Ratner, D.; /SLAC /LLNL, Livermore

    2010-06-15

    The Linac Coherent Light Source (LCLS) X-ray FEL utilizing the last km of the SLAC linac has been operational since April 2009 and finished its first successful user run last December. The various diagnostics for electron beam properties including beam position monitors, wire scanners, beam profile monitors, and bunch length diagnostics are presented as well as diagnostics for the X-ray beam. The low emittance and ultra-short electron beam required for X-ray FEL operation has implications on the transverse and longitudinal diagnostics. The coherence effects of the beam profile monitors and the challenges of measuring fs long bunches are discussed.

  5. Flow sensing by buckling monitoring of electrothermally actuated double-clamped micro beams

    NASA Astrophysics Data System (ADS)

    Kessler, Y.; Krylov, S.; Liberzon, A.

    2016-08-01

    We report on a flow sensing approach based on deflection monitoring of a micro beam buckled by the compressive thermal stress due to electrothermal Joule's heating. The air stream, convectively cooling the device, affects both the critical buckling values of the electric current and the postbuckling deflections of the structure. After calibration, the flow velocity can be obtained from the deflection measurements. The quasi-static responses of 1000 μm and 2000 μm long, 10 μm wide, and 30 μm high single crystal silicon beams were consistent with the prediction of the model, which couples thermoelectric, thermofluidic, and structural domains. The deflection sensitivity of up to 1.5 μm/(m/s) and the critical current sensitivity of up to 0.43 mA/(m/s) were registered in the experiments. Our model and experimental results demonstrate the feasibility of the sensing approach and further suggest that simple, robust, and potentially downscalable beam-type devices may have use in flow velocity and wall shear stress sensors.

  6. Analyzing the characteristics of 6 MV photon beam at low monitor unit settings.

    PubMed

    Nithya, L; Raj, N Arunai Nambi; Rathinamuthu, Sasikumar

    2016-01-01

    Analyzing the characteristics of a low monitor unit (MU) setting is essential, particularly for intensity-modulated techniques. Intensity modulation can be achieved through intensity-modulated radiotherapy (IMRT) or volumetric-modulated arc therapy (VMAT). There is possibility for low MUs in the segments of IMRT and VMAT plans. The minimum MU/segment must be set by the physicist in the treatment planning system at the time of commissioning. In this study, the characteristics such as dose linearity, stability, flatness, and symmetry of 6 MV photon beam of a Synergy linear accelerator at low MU settings were investigated for different dose rates. The measurements were performed for Synergy linear accelerator using a slab phantom with a FC65-G chamber and Profiler 2. The MU linearity was studied for 1-100 MU using a field size of 10 cm ×10 cm. The linearity error for 1 MU was 4.2%. Flatness of the beam was deteriorated in 1 MU condition. The beam stability and symmetry was well within the specification. Using this study, we conclude that the treatment delivered with <3 MU may result in uncertainty in dose delivery. To ensure the correct dose delivery with less uncertainty, it is recommended to use ≥3 MU as the minimum MU per segment in IMRT and VMAT plans. PMID:27051168

  7. Investigations of high mobility single crystal chemical vapor deposition diamond for radiotherapy photon beam monitoring

    NASA Astrophysics Data System (ADS)

    Tromson, D.; Descamps, C.; Tranchant, N.; Bergonzo, P.; Nesladek, M.; Isambert, A.

    2008-03-01

    The intrinsic properties of diamond make this material theoretically very suitable for applications in medical physics. Until now ionization chambers have been fabricated from natural stones and are commercialized by PTW, but their fairly high costs and long delivery times have often limited their use in hospital. The properties of commercialized intrinsic polycrystalline diamond were investigated in the past by many groups. The results were not completely satisfactory due to the nature of the polycrystalline material itself. In contrast, the recent progresses in the growth of high mobility single crystal synthetic diamonds prepared by chemical vapor deposition (CVD) technique offer new alternatives. In the framework of the MAESTRO project (Methods and Advanced Treatments and Simulations for Radio Oncology), the CEA-LIST is studying the potentialities of synthetic diamond for new techniques of irradiation such as intensity modulated radiation therapy. In this paper, we present the growth and characteristics of single crystal diamond prepared at CEA-LIST in the framework of the NoRHDia project (Novel Radiation Hard CVD Diamond Detector for Hadrons Physics), as well as the investigations of high mobility single crystal CVD diamond for radiotherapy photon beam monitoring: dosimetric analysis performed with the single crystal diamond detector in terms of stability and repeatability of the response signal, signal to noise ratio, response speed, linearity of the signal versus the absorbed dose, and dose rate. The measurements performed with photon beams using radiotherapy facilities demonstrate that single crystal CVD diamond is a good alternative for air ionization chambers for beam quality control.

  8. Positive peer pressure: the effects of peer monitoring on children's disruptive behavior.

    PubMed

    Carden Smith, L K; Fowler, S A

    1984-01-01

    Classroom peers can serve as powerful sources of reinforcement in increasing or maintaining both the positive and negative behaviors of their classmates. In two experiments, we examined the effectiveness of a peer-monitored token system on reducing disruption and nonparticipation during a transition period of a kindergarten class for behaviorally impaired children. Additionally, the effect of providing and subsequently withholding corrective feedback to peer mediators on the accuracy of their point awards was evaluated. Results in Experiment 1 suggest that both teacher- and peer-monitored interventions were successful in decreasing disruption and increasing participation of monitored peers. Experiment 2 further demonstrated that peer monitors could successfully initiate the token system without prior adult implementation. Analysis of the point awards in both experiments indicates that peer monitors consistently awarded points that were earned. However, when corrective feedback was withdrawn the peer monitors frequently awarded points that were not earned, i.e., they rarely withheld points for undesirable behavior. Even so, the monitored peers' disruptive behavior was maintained at low rates. PMID:6735953

  9. Positive peer pressure: the effects of peer monitoring on children's disruptive behavior.

    PubMed

    Carden Smith, L K; Fowler, S A

    1984-01-01

    Classroom peers can serve as powerful sources of reinforcement in increasing or maintaining both the positive and negative behaviors of their classmates. In two experiments, we examined the effectiveness of a peer-monitored token system on reducing disruption and nonparticipation during a transition period of a kindergarten class for behaviorally impaired children. Additionally, the effect of providing and subsequently withholding corrective feedback to peer mediators on the accuracy of their point awards was evaluated. Results in Experiment 1 suggest that both teacher- and peer-monitored interventions were successful in decreasing disruption and increasing participation of monitored peers. Experiment 2 further demonstrated that peer monitors could successfully initiate the token system without prior adult implementation. Analysis of the point awards in both experiments indicates that peer monitors consistently awarded points that were earned. However, when corrective feedback was withdrawn the peer monitors frequently awarded points that were not earned, i.e., they rarely withheld points for undesirable behavior. Even so, the monitored peers' disruptive behavior was maintained at low rates.

  10. Comparison of different coil positions for ventilation monitoring with contact-less magnetic impedance measurements

    NASA Astrophysics Data System (ADS)

    Cordes, A.; Pollig, D.; Leonhardt, S.

    2010-04-01

    For monitoring the health status of individuals, proper monitoring of ventilation is desirable. Therefore, a continuous measurement technique is an advantage for many patients since it allows personal home care scenarios. As an example, monitoring of elderly people at home could enable them to live in their familiar environment on their own with the safety of a continuous monitoring. Therefore, a measurement technique without the restriction of mobility is required. Since it is possible to monitor ventilation with magnetic impedance measurements without conductive contact, this technique is well suited for the mentioned scenario. Integrated in a chair, a person's health state could be monitored in many situations, e.g. during meals, while watching TV or reading a book. In this paper, we compare different positions of coil arrays for a magnetic impedance measurement system integrated in a chair in order to monitor ventilation continuously. For limiting the costs and technical complexity of the magnetic impedance measurement system, we have a focus on coil configurations with one RF channel. To limit the needed space and thickness of the array in the backrest, planar gradiometer coil setups are investigated. All measurements will be performed with a new developed portable magnetic impedance measurement system and a standard office chair.

  11. Monitoring tumor motion with on-line mega-voltage cone-beam computed tomography imaging in a cine mode

    NASA Astrophysics Data System (ADS)

    Reitz, Bodo; Gayou, Olivier; Parda, David S.; Miften, Moyed

    2008-02-01

    Accurate daily patient localization is becoming increasingly important in external-beam radiotherapy (RT). Mega-voltage cone-beam computed tomography (MV-CBCT) utilizing a therapy beam and an on-board electronic portal imager can be used to localize tumor volumes and verify the patient's position prior to treatment. MV-CBCT produces a static volumetric image and therefore can only account for inter-fractional changes. In this work, the feasibility of using the MV-CBCT raw data as a fluoroscopic series of portal images to monitor tumor changes due to e.g. respiratory motion was investigated. A method was developed to read and convert the CB raw data into a cine. To improve the contrast-to-noise ratio on the MV-CB projection data, image post-processing with filtering techniques was investigated. Volumes of interest from the planning CT were projected onto the MV-cine. Because of the small exposure and the varying thickness of the patient depending on the projection angle, soft-tissue contrast was limited. Tumor visibility as a function of tumor size and projection angle was studied. The method was well suited in the upper chest, where motion of the tumor as well as of the diaphragm could be clearly seen. In the cases of patients with non-small cell lung cancer with medium or large tumor masses, we verified that the tumor mass was always located within the PTV despite respiratory motion. However for small tumors the method is less applicable, because the visibility of those targets becomes marginal. Evaluation of motion in non-superior-inferior directions might also be limited for small tumor masses. Viewing MV-CBCT data in a cine mode adds to the utility of MV-CBCT for verification of tumor motion and for deriving individualized treatment margins.

  12. Monitoring tumor motion with on-line mega-voltage cone-beam computed tomography imaging in a cine mode.

    PubMed

    Reitz, Bodo; Gayou, Olivier; Parda, David S; Miften, Moyed

    2008-02-21

    Accurate daily patient localization is becoming increasingly important in external-beam radiotherapy (RT). Mega-voltage cone-beam computed tomography (MV-CBCT) utilizing a therapy beam and an on-board electronic portal imager can be used to localize tumor volumes and verify the patient's position prior to treatment. MV-CBCT produces a static volumetric image and therefore can only account for inter-fractional changes. In this work, the feasibility of using the MV-CBCT raw data as a fluoroscopic series of portal images to monitor tumor changes due to e.g. respiratory motion was investigated. A method was developed to read and convert the CB raw data into a cine. To improve the contrast-to-noise ratio on the MV-CB projection data, image post-processing with filtering techniques was investigated. Volumes of interest from the planning CT were projected onto the MV-cine. Because of the small exposure and the varying thickness of the patient depending on the projection angle, soft-tissue contrast was limited. Tumor visibility as a function of tumor size and projection angle was studied. The method was well suited in the upper chest, where motion of the tumor as well as of the diaphragm could be clearly seen. In the cases of patients with non-small cell lung cancer with medium or large tumor masses, we verified that the tumor mass was always located within the PTV despite respiratory motion. However for small tumors the method is less applicable, because the visibility of those targets becomes marginal. Evaluation of motion in non-superior-inferior directions might also be limited for small tumor masses. Viewing MV-CBCT data in a cine mode adds to the utility of MV-CBCT for verification of tumor motion and for deriving individualized treatment margins.

  13. In-beam PET monitoring of mono-energetic (16)O and (12)C beams: experiments and FLUKA simulations for homogeneous targets.

    PubMed

    Sommerer, F; Cerutti, F; Parodi, K; Ferrari, A; Enghardt, W; Aiginger, H

    2009-07-01

    (16)O and (12)C ion beams will be used-besides lighter ions-for cancer treatment at the Heidelberg Ion Therapy Center (HIT), Germany. It is planned to monitor the treatment by means of in-beam positron emission tomography (PET) as it is done for therapy with (12)C beams at the experimental facility at the Gesellschaft für Schwerionenforschung (GSI), Darmstadt, Germany. To enable PET also for (16)O beams, experimental data of the beta(+)-activity created by these beams are needed. Therefore, in-beam PET measurements of the activity created by (16)O beams of various energies on targets of PMMA, water and graphite were performed at GSI for the first time. Additionally reference measurements of (12)C beams on the same target materials were done. The results of the measurements are presented. The deduction of clinically relevant results from in-beam PET data requires reliable simulations of the beta(+)-activity production, which is done presently by a dedicated code limited to (12)C beams. Because this code is not extendable to other ions in an easy way, a new code, capable of simulating the production of the beta(+)-activity by all ions of interest, is needed. Our choice is the general purpose Monte Carlo code FLUKA which was used to simulate the ion transport, the beta(+)-active isotope production, the decay, the positron annihilation and the transport of the annihilation photons. The detector response was simulated with an established software that gives the output in the same list-mode data format as in the experiment. This allows us to use the same software to reconstruct measured and simulated data, which makes comparisons easier and more reliable. The calculated activity distribution shows general good agreement with the measurements. PMID:19494424

  14. Measurement of charged particle yields from therapeutic beams in view of the design of an innovative hadrontherapy dose monitor

    NASA Astrophysics Data System (ADS)

    Battistoni, G.; Bellini, F.; Bini, F.; Collamati, F.; Collini, F.; De Lucia, E.; Durante, M.; Faccini, R.; Ferroni, F.; Frallicciardi, P. M.; La Tessa, C.; Marafini, M.; Mattei, I.; Miraglia, F.; Morganti, S.; Ortega, P. G.; Patera, V.; Piersanti, L.; Pinci, D.; Russomando, A.; Sarti, A.; Schuy, C.; Sciubba, A.; Senzacqua, M.; Solfaroli Camillocci, E.; Vanstalle, M.; Voena, C.

    2015-02-01

    Particle Therapy (PT) is an emerging technique, which makes use of charged particles to efficiently cure different kinds of solid tumors. The high precision in the hadrons dose deposition requires an accurate monitoring to prevent the risk of under-dosage of the cancer region or of over-dosage of healthy tissues. Monitoring techniques are currently being developed and are based on the detection of particles produced by the beam interaction into the target, in particular: charged particles, result of target and/or projectile fragmentation, prompt photons coming from nucleus de-excitation and back-to-back γ s, produced in the positron annihilation from β + emitters created in the beam interaction with the target. It has been showed that the hadron beam dose release peak can be spatially correlated with the emission pattern of these secondary particles. Here we report about secondary particles production (charged fragments and prompt γ s) performed at different beam and energies that have a particular relevance for PT applications: 12C beam of 80 MeV/u at LNS, 12C beam 220 MeV/u at GSI, and 12C, 4He, 16O beams with energy in the 50-300 MeV/u range at HIT. Finally, a project for a multimodal dose-monitor device exploiting the prompt photons and charged particles emission will be presented.

  15. Commercial CMOS image sensors as X-ray imagers and particle beam monitors

    NASA Astrophysics Data System (ADS)

    Castoldi, A.; Guazzoni, C.; Maffessanti, S.; Montemurro, G. V.; Carraresi, L.

    2015-01-01

    CMOS image sensors are widely used in several applications such as mobile handsets webcams and digital cameras among others. Furthermore they are available across a wide range of resolutions with excellent spectral and chromatic responses. In order to fulfill the need of cheap systems as beam monitors and high resolution image sensors for scientific applications we exploited the possibility of using commercial CMOS image sensors as X-rays and proton detectors. Two different sensors have been mounted and tested. An Aptina MT9v034, featuring 752 × 480 pixels, 6μm × 6μm pixel size has been mounted and successfully tested as bi-dimensional beam profile monitor, able to take pictures of the incoming proton bunches at the DeFEL beamline (1-6 MeV pulsed proton beam) of the LaBeC of INFN in Florence. The naked sensor is able to successfully detect the interactions of the single protons. The sensor point-spread-function (PSF) has been qualified with 1MeV protons and is equal to one pixel (6 mm) r.m.s. in both directions. A second sensor MT9M032, featuring 1472 × 1096 pixels, 2.2 × 2.2 μm pixel size has been mounted on a dedicated board as high-resolution imager to be used in X-ray imaging experiments with table-top generators. In order to ease and simplify the data transfer and the image acquisition the system is controlled by a dedicated micro-processor board (DM3730 1GHz SoC ARM Cortex-A8) on which a modified LINUX kernel has been implemented. The paper presents the architecture of the sensor systems and the results of the experimental measurements.

  16. Controllable in-situ cell electroporation with cell positioning and impedance monitoring using micro electrode array

    PubMed Central

    Guo, Xiaoliang; Zhu, Rong

    2016-01-01

    This paper reports a novel microarray chip for in-situ, real-time and selective electroporation on individual cells integrated with cell positioning and impedance monitoring. An array of quadrupole-electrode units (termed positioning electrodes) and pairs of planar center electrodes located at the centers of each quadrupole-electrode unit were fabricated on the chip. The positioning electrodes are used to trap and position living cells onto the center electrodes based on negative dielectrophoresis (nDEP). The center electrodes are used for in-situ cell electroporation, and also used to measure cell impedance for monitoring cellular dynamics in real time. Controllably selective electroporation and electrical measurement on the cells in array are realized. We present an evidence of selective electroporation through use of fluorescent dyes. Subsequently we use in-situ and real-time impedance measurement to monitor the process, which demonstrates the dynamic behavior of the cell electroporation. Finally, we show the use of this device to perform successful transfection onto individual HeLa cells with vector DNA encoding a green fluorescent. PMID:27507603

  17. Investigation of the d(γ,n)p reaction for gamma beam monitoring at ELI-NP

    NASA Astrophysics Data System (ADS)

    Matei, C.; Mueller, J. M.; Sikora, M. H.; Suliman, G.; Ur, C. A.; Weller, H. R.

    2016-05-01

    The Extreme Light Infrastructure - Nuclear Physics facility will deliver brilliant gamma beams with high spectral density and a high degree of polarization starting in 2018 in Bucharest-Magurele, Romania. Several monitoring instruments are proposed for measuring the spectral, temporal, and spatial characteristics of the gamma beam. The d(γ,n)p reaction has been investigated for its use in determining the gamma beam parameters in a series of measurements carried out at the High Intensity Gamma Source, Durham, U.S.A.. Measurements of the emitted neutrons have been performed using liquid scintillator and 6Li-glass neutron detectors at several incident gamma energies between 2.5 to 20 MeV . The experimental results presented in this paper have shown that an instrument based on the d(γ,n)p reaction can be used to monitor the intensity and polarization of the gamma beam to be produced at ELI-NP.

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

    PubMed Central

    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

  19. Absolute measurement of electron-cloud density in a positively charged particle beam.

    PubMed

    Kireeff Covo, Michel; Molvik, Arthur W; Friedman, Alex; Vay, Jean-Luc; Seidl, Peter A; Logan, Grant; Baca, David; Vujic, Jasmina L

    2006-08-01

    Clouds of stray electrons are ubiquitous in particle accelerators and frequently limit the performance of storage rings. Earlier measurements of electron energy distribution and flux to the walls provided only a relative electron-cloud density. We have measured electron accumulation using ions expelled by the beam. The ion energy distribution maps the depressed beam potential and gives the dynamic cloud density. Clearing electrode current reveals the static background cloud density, allowing the first absolute measurement of the time-dependent electron-cloud density during the beam pulse.

  20. Development of an optical transition radiation detector for profile monitoring of antiproton and proton beams at FNAL

    SciTech Connect

    Scarpine, V.E.; Lindenmeyer, C.W.; Tassotto, G.R.; Lumpkin, A.H.; /Argonne

    2005-05-01

    Optical transition radiation (OTR) detectors are being developed at Fermi National Accelerator Laboratory (FNAL) as part of the collider Run II upgrade program and as part of the NuMI primary beam line. These detectors are designed to measure 150 GeV antiprotons as well as 120 GeV proton beams over a large range of intensities. Design and development of an OTR detector capable of measuring beam in both directions down to beam intensities of {approx}5e9 particles for nominal beam sizes are presented. Applications of these OTR detectors as an on-line emittance monitor for both antiproton transfers and reverse-injected protons, as a Tevatron injection profile monitor, and as a high-intensity beam profile monitor for NuMI are discussed. In addition, different types of OTR foils are being evaluated for operation over the intensity range of {approx}5e9 to 5e13 particles per pulse, and these are described.

  1. In situ stress monitoring of the concrete beam under static loading with cement-based piezoelectric sensors

    NASA Astrophysics Data System (ADS)

    Dong, Biqin; Liu, Yuqing; Qin, Lei; Wang, Yaocheng; Fang, Yuan; Xing, Feng; Chen, Xianchuan

    2015-10-01

    In this paper, the application of a novel cement-based piezoelectric ceramic sensor is stated for the in situ stress monitoring of the reinforced concrete beam under static loading. Smart beam composite structures were designed and characterised by a range of experimental methods. Finite element analysis is used to analyse the mechanical response of the concrete beam under static loading. The results show that the mechanical-electrical response of sensors embedded in reinforced concrete beams follows a linear relationship under various loading conditions. The sensors are able to record the stress history of the beam under static loads. Moreover, the measured stress data agree well with the simulated results and the smart structures are found to be capable of reliably monitoring the response of a beam during stress testing for static loading modes to real concrete structures. The study indicates that such cement-based piezoelectric composites have a high feasibility and applicability to the in situ stress monitoring of reinforced concrete structures.

  2. Adjustment procedure for beam alignment in scanned ion-beam therapy

    NASA Astrophysics Data System (ADS)

    Saraya, Y.; Takeshita, E.; Furukawa, T.; Hara, Y.; Mizushima, K.; Saotome, N.; Tansho, R.; Shirai, T.; Noda, K.

    2016-09-01

    Control of the beam position for three-dimensional pencil-beam scanning is important because the position accuracy of the beam significantly impacts the alignment of the irradiation field. To suppress this effect, we have developed a simple procedure for beamline tuning. At first, beamline tuning is performed with steering magnets and fluorescent screen monitors to converge the beam's trajectory to a central orbit. Misalignment between the beam's position and the reference axis is checked by using the verification system, which consists of a screen monitor and an acrylic phantom. If the beam position deviates from the reference axis, two pairs of steering magnets, which are placed on downstream of the beam transport line, will be corrected. These adjustments are iterated until the deviations for eleven energies of the beam are within 0.5 mm of the reference axis. To demonstrate the success of our procedure, we used our procedure to perform beam commissioning at the Kanagawa Cancer Center.

  3. A COMPACTRIO-BASED BEAM LOSS MONITOR FOR THE SNS RF TEST CAVE

    SciTech Connect

    Blokland, Willem; Armstrong, Gary A

    2009-01-01

    An RF Test Cave has been built at the Spallation Neutron Source (SNS) to be able to test RF cavities without interfering the SNS accelerator operations. In addition to using thick concrete wall to minimize radiation exposure, a Beam Loss Monitor (BLM) must abort the operation within 100 usec when the integrated radiation within the cave exceeds a threshold. We choose the CompactRIO platform to implement the BLM based on its performance, cost-effectiveness, and rapid development. Each in/output module is connected through an FPGA to provide point-by-point processing. Every 10 usec the data is acquired analyzed and compared to the threshold. Data from the FPGA is transferred using DMA to the real-time controller, which communicates to a gateway PC to talk to the SNS control system. The system includes diagnostics to test the hardware and integrates the losses in real-time. In this paper we describe our design, implementation, and results

  4. Analytical methods and monitoring system for E-beam flue gas treatment process

    NASA Astrophysics Data System (ADS)

    Licki, J.; Chmielewski, A. G.; Iller, E.; Zakrzewska-Trznadel, G.; Tokunaga, O.; Hashimoto, S.

    1998-06-01

    The results of reliable and precise measurement of gas composition in different key points of e-beam installation are necessary for its proper operation and control. Only the composition of flue gas coming into installation is adequate to composition of flue gas emitted from coal-fired boiler. At other points of e-b installation the gas composition is strongly modified by process conditions therefore specific measuring system (sampling and conditioning system and set of gas analyzers) for its determination are required. In the paper system for gas composition measurement at inlet and outlet of e-b installation are described. Process parameters are continuously monitoring by CEM system and occasionally by the grab sample system. Both system have been tested at pilot plant at EPS Kawȩczyn.

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

    NASA Astrophysics Data System (ADS)

    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

  6. Feasibility study of patient positioning verification in electron beam radiotherapy with an electronic portal imaging device (EPID).

    PubMed

    Ramm, U; Köhn, J; Rodriguez Dominguez, R; Licher, J; Koch, N; Kara, E; Scherf, C; Rödel, C; Weiß, C

    2014-03-01

    The purpose of this study is to demonstrate the feasibility of verification and documentation in electron beam radiotherapy using the photon contamination detected with an electronic portal imaging device. For investigation of electron beam verification with an EPID, the portal images are acquired irradiating two different tissue equivalent phantoms at different electron energies. Measurements were performed on an Elekta SL 25 linear accelerator with an amorphous-Si electronic portal imaging device (EPID: iViewGT, Elekta Oncology Systems, Crawley, UK). As a measure of EPID image quality contrast (CR) and signal-to-noise ratio (SNR) are determined. For characterisation of the imaging of the EPID RW3 slabs and a Gammex 467 phantom with different material inserts are used. With increasing electron energy the intensity of photon contamination increases, yielding an increasing signal-to-noise ratio, but images are showing a decreasing contrast. As the signal-to-noise ratio saturates with increasing dose a minimum of 50 MUs is recommended. Even image quality depends on electron energy and diameter of the patient, the acquired results are mostly sufficient to assess the accuracy of beam positioning. In general, the online EPID acquisition has been demonstrated to be an effective electron beam verification and documentation method. The results are showing that this procedure can be recommended to be routinely and reliably done in patient treatment with electron beams.

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

    PubMed Central

    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

  8. The data quality monitoring system of non-cable self-positioning seismographs

    NASA Astrophysics Data System (ADS)

    Zheng, F.; Lin, J.; Linhang, Z.; Hongyuan, Y.; Zubin, C.; Huaizhu, Z.; Sun, F.

    2013-12-01

    Seismic exploration is the most effective and promising geophysical exploration methods, it inverts underground geological structure by recording crust vibration caused by nature or artificial means. In order to get rid of the long-term dependence on imported seismographs, China pays more and more attention to the independent research and development of seismic exploration equipment. This study is based on the self-invented non-cable self-positioning seismographs of Jilin University. Non-cable seismographs have many advantages such as simple arrangement, light, easy to move, easy to maintain, low price, large storage space and high-quality data, they especially apply to complex terrain and field construction environment inconvenient laying big lines. The built-in integration of GPS realizes precise clock synchronization, fast and accurate self-positioning for non-cable seismographs. The low power design and the combination of built-in rechargeable battery and external power can effectively improve non-cable seismographs` working time, which ensures the stability of exploration and construction. In order to solve the problem that the non-cable seismographs are difficult to on-site data monitor and also to provide non-cable seismographs` ability of real-time data transmission, We integrate the wireless communication technology into non-cable seismographs, combing instrument, electronic, communication, computer and many other subject knowledge, design and develop seismic exploration field work control system and seismic data management system. Achieve two research objectives which are real-time data quality monitoring in the resource exploration field and status monitoring of large trace spacing long-term observations for seismographs. Through several field experiments in different regions, we accumulate a wealth of experience, and the experiments effectively prove the good practical performance of non-cable self-positioning seismographs and data quality monitoring

  9. A real-time applicator position monitoring system for gynecologic intracavitary brachytherapy

    SciTech Connect

    Xia, Junyi Waldron, Timothy; Kim, Yusung

    2014-01-15

    Purpose: To develop a real-time applicator position monitoring system (RAPS) for intracavitary brachytherapy using an infrared camera and reflective markers. Methods: 3D image-guided brachytherapy requires high accuracy of applicator localization; however, applicator displacement can happen during patient transfer for imaging and treatment delivery. No continuous applicator position monitoring system is currently available. The RAPS system was developed for real-time applicator position monitoring without additional radiation dose to patients. It includes an infrared camera, reflective markers, an infrared illuminator, and image processing software. After reflective markers are firmly attached to the applicator and the patient body, applicator displacement can be measured by computing the relative change in distance between the markers. The reflective markers are magnetic resonance imaging (MRI) compatible, which is suitable for MRI-guided HDR brachytherapy paradigm. In our prototype, a Microsoft Kinect sensor with a resolution of 640 by 480 pixels is used as an infrared camera. A phantom study was carried out to compare RAPS' measurements with known displacements ranging from −15 to +15 mm. A reproducibility test was also conducted. Results: The RAPS can achieve 4 frames/s using a laptop with Intel{sup ®} Core™2 Duo processor. When the pixel size is 0.95 mm, the difference between RAPS' measurements and known shift values varied from 0 to 0.8 mm with the mean value of 0.1 mm and a standard deviation of 0.44 mm. The system reproducibility was within 0.6 mm after ten reposition trials. Conclusions: This work demonstrates the feasibility of a real-time infrared camera based gynecologic intracavitary brachytherapy applicator monitoring system. Less than 1 mm accuracy is achieved when using an off-the-shelf infrared camera.

  10. A Wire Position Monitor System for the 1.3 FHZ Tesla-Style Cryomodule at the Fermilab New-Muon-Lab Accelerator

    SciTech Connect

    Eddy, N.; Fellenz, B.; Prieto, P.; Semenov, A.; Voy, D.C.; Wendt, M.; /Fermilab

    2011-08-17

    The first cryomodule for the beam test facility at the Fermilab New-Muon-Lab building is currently under RF commissioning. Among other diagnostics systems, the transverse position of the helium gas return pipe with the connected 1.3 GHz SRF accelerating cavities is measured along the {approx}15 m long module using a stretched-wire position monitoring system. An overview of the wire position monitor system technology is given, along with preliminary results taken at the initial module cooldown, and during further testing. As the measurement system offers a high resolution, we also discuss options for use as a vibration detector. An electron beam test facility, based on superconducting RF (SRF) TESLA-style cryomodules is currently under construction at the Fermilab New-Muon-Lab (NML) building. The first, so-called type III+, cryomodule (CM-1), equipped with eight 1.3 GHz nine-cell accelerating cavities was recently cooled down to 2 K, and is currently under RF conditioning. The transverse alignment of the cavity string within the cryomodule is crucial for minimizing transverse kick and beam break-up effects, generated by the high-order dipole modes of misaligned accelerating structures. An optimum alignment can only be guaranteed during the assembly of the cavity string, i.e. at room temperatures. The final position of the cavities after cooldown is uncontrollable, and therefore unknown. A wire position monitoring system (WPM) can help to understand the transverse motion of the cavities during cooldown, their final location and the long term position stability after cryo-temperatures are settled, as well as the position reproducibility for several cold-warm cycles. It also may serve as vibration sensor, as the wire acts as a high-Q resonant detector for mechanical vibrations in the low-audio frequency range. The WPM system consists out of a stretched-wire position detection system, provided with help of INFN-Milano and DESY Hamburg, and RF generation and read

  11. Thermographic In-Situ Process Monitoring of the Electron Beam Melting Technology used in Additive Manufacturing

    SciTech Connect

    Dinwiddie, Ralph Barton; Dehoff, Ryan R; Lloyd, Peter D; Lowe, Larry E; Ulrich, Joseph B

    2013-01-01

    Oak Ridge National Laboratory (ORNL) has been utilizing the ARCAM electron beam melting technology to additively manufacture complex geometric structures directly from powder. Although the technology has demonstrated the ability to decrease costs, decrease manufacturing lead-time and fabricate complex structures that are impossible to fabricate through conventional processing techniques, certification of the component quality can be challenging. Because the process involves the continuous deposition of successive layers of material, each layer can be examined without destructively testing the component. However, in-situ process monitoring is difficult due to metallization on inside surfaces caused by evaporation and condensation of metal from the melt pool. This work describes a solution to one of the challenges to continuously imaging inside of the chamber during the EBM process. Here, the utilization of a continuously moving Mylar film canister is described. Results will be presented related to in-situ process monitoring and how this technique results in improved mechanical properties and reliability of the process.

  12. Cost-reduction method for delamination monitoring using electrical resistance changes of CFRP beam

    NASA Astrophysics Data System (ADS)

    Todoroki, A.; Ueda, M.

    2004-02-01

    Delamination is a significant defect of laminated composites. The present study employs an electrical resistance change method in an attempt to identify internal delaminations experimentally. The method adopts reinforcing carbon fibers as sensors. In our previous paper, an actual delamination crack in a Carbon Fiber Reinforced Plastics (CFRP) laminate was experimentally identified with artificial neural networks (ANN) or response surfaces created from a large number of experiments. The experimental results were used for learning of the ANN or regression of the response surfaces. For the actual application of the method, it is indispensable to reduce the number of experiments to suppress the total experimental cost. In the present study, therefore, FEM analyses are employed to make sets of data for learning of the ANN. First, electrical conductivity of the CFRP laminate is identified by means of the least estimation error method. After that, the results of FEM analyses are used for learning of the ANN. The method is applied to actual delamination monitoring of CFRP beams. As a result, the method successfully monitored the delamination location and size only with ten experiments.

  13. Monitoring of intracranial compliance: correction for a change in body position.

    PubMed

    Raabe, A; Czosnyka, M; Piper, I; Seifert, V

    1999-01-01

    The objectives of our study were 1. to investigate whether the intracranial compliance changes with body position; 2. to test if the pressure-volume index (PVI) calculation is affected by different body positions; 3. to define the optimal parameter to correct PVI for changes in body position and 4. to investigate the physiological meaning of the constant term (P0) in the model of the intracranial volume-pressure relationship. Thirteen patients were included in this study. All patients were subjected to 2 to 3 different body positions. In each position, either classic bolus injection was performed for measurement of intracranial compliance and calculation of PVI or the new Spiegelberg compliance monitor was used to calculate PVI continuously. Four different models were used for calculating the constant pressure term P0 and the P0 corrected PVI values. Pressure volume index not corrected for the constant term P0 significantly decreased with elevating the patients head (r = 0.70, p < 0.0001). In contrast, volume-pressure response and ICP pulse amplitude did not change with position. Using the constant term P0 to correct the PVI we found no changes between the different body positions. Our results suggest that during the variation in body position there is no change in intracranial compliance but a change in hydrostatic offset pressure which causes a shifting of the volume-pressure curve along the pressure axis without its shape being affected. PVI measurements should either be performed only with the patient in the 0 degree recumbent position or that the PVI calculation should be corrected for the hydrostatic difference between the level of the ICP transducer and the hydrostatic indifference point of the craniospinal system close to the third thoracic vertebra. PMID:10071684

  14. Accelerometer's position independent physical activity recognition system for long-term activity monitoring in the elderly.

    PubMed

    Khan, Adil Mehmood; Lee, Young-Koo; Lee, Sungyoung; Kim, Tae-Seong

    2010-12-01

    Mobility is a good indicator of health status and thus objective mobility data could be used to assess the health status of elderly patients. Accelerometry has emerged as an effective means for long-term physical activity monitoring in the elderly. However, the output of an accelerometer varies at different positions on a subject's body, even for the same activity, resulting in high within-class variance. Existing accelerometer-based activity recognition systems thus require firm attachment of the sensor to a subject's body. This requirement makes them impractical for long-term activity monitoring during unsupervised free-living as it forces subjects into a fixed life pattern and impede their daily activities. Therefore, we introduce a novel single-triaxial-accelerometer-based activity recognition system that reduces the high within-class variance significantly and allows subjects to carry the sensor freely in any pocket without its firm attachment. We validated our system using seven activities: resting (lying/sitting/standing), walking, walking-upstairs, walking-downstairs, running, cycling, and vacuuming, recorded from five positions: chest pocket, front left trousers pocket, front right trousers pocket, rear trousers pocket, and inner jacket pocket. Its simplicity, ability to perform activities unimpeded, and an average recognition accuracy of 94% make our system a practical solution for continuous long-term activity monitoring in the elderly.

  15. Summary report of working group 5 : beam generation, monitoring, and control.;

    SciTech Connect

    Lewellen, J. W.; Piot, P.; Accelerator Systems Division; Northern Illinois Univ.

    2006-01-01

    The working group on beam quality, diagnostics, and control at the 12th Advanced Accelerator Concepts Workshop held a series of meetings during the Workshop. The generation of bright charged-particle beams (in particular electron and positron beams), along with state-of-the-art beam diagnostics and synchronization were discussed.

  16. Summary report: Working Group 4 on 'Beam Monitoring, Conditioning, and Control at High Frequencies and Ultrafast Timescales'

    SciTech Connect

    Smith, Todd I.

    1999-07-12

    Working Group 4 at the 8th Advanced Accelerator Concepts Workshop (ACC'98), held July 5-11, 1998 in Baltimore, Maryland hosted more than fifteen scheduled or impromptu talks (all punctuated with lively discussion) on the general topic of 'Beam Monitoring, Conditioning, and Control at High Frequencies and Ultrafast Timescales'. This report is a summary of these talks and discussions.

  17. Fragmentation of positively-charged biological ions activated with a beam of high-energy cations.

    PubMed

    Chingin, Konstantin; Makarov, Alexander; Denisov, Eduard; Rebrov, Oleksii; Zubarev, Roman A

    2014-01-01

    First results are reported on the fragmentation of multiply protonated polypeptide ions produced in electrospray ionization mass spectrometry (ESI-MS) with a beam of high-energy cations as a source of activation. The ion beam is generated with a microwave plasma gun installed on a benchtop Q Exactive mass spectrometer. Precursor polypeptide ions are activated when trapped inside the collision cell of the instrument (HCD cell), and product species are detected in the Orbitrap analyzer. Upon exposure to the beam of air plasma cations (∼100 μA, 5 s), model precursor species such as multiply protonated angiotensin I and ubiquitin dissociated across a variety of pathways. Those pathways include the cleavages of C-CO, C-N as well as N-Cα backbone bonds, accordingly manifested as b/y, a, and c/z fragment ion series in tandem mass spectra. The fragmentation pattern observed includes characteristic fragments of collision-induced dissociation (CID) (b/y/a fragments) as well as electron capture/transfer dissociation (ECD, ETD) (c/z fragments), suggesting substantial contribution of both vibrational and electronic excitation in our experiments. Besides backbone cleavages, notable amounts of nondissociated precursor species were observed with reduced net charge, formed via electron or proton transfer between the colliding partners. Peaks corresponding to increased charge states of the precursor ions were also detected, which is the major distinctive feature of ion beam activation.

  18. Gap and stripline combined monitor

    DOEpatents

    Yin, Y.

    1986-08-19

    A combined gap and stripline monitor device for measuring the intensity and position of a charged particle beam bunch in a beam pipe of a synchrotron radiation facility is disclosed. The monitor has first and second beam pipe portions with an axial gap therebetween. An outer pipe cooperates with the first beam pipe portion to form a gap enclosure, while inner strips cooperate with the first beam pipe portion to form a stripline monitor, with the stripline length being the same as the gap enclosure length. 4 figs.

  19. Gap and stripline combined monitor

    DOEpatents

    Yin, Y.

    1984-02-16

    A combined gap and stripline monitor device for measuring the intensity and position of a charged particle beam bunch in a beam pipe of a synchrotron radiation facility. The monitor has first and second beam pipe portions with an axial gap therebetween. An outer pipe cooperates with the first beam pipe portion to form a gap enclosure, while inner strips cooperate with the first beam pipe portion to form a stripline monitor, with the stripline length being the same as the gap enclosure length.

  20. Gap and stripline combined monitor

    DOEpatents

    Yin, Yan

    1986-01-01

    A combined gap and stripline monitor device (10) for measuring the intensity and position of a charged particle beam bunch in a beam pipe of a synchotron radiation facility. The monitor has first and second beam pipe portions (11a, 11b) with an axial gap (12) therebetween. An outer pipe (14) cooperates with the first beam pipe portion (11a) to form a gap enclosure, while inner strips (23a-d) cooperate with the first beam pipe portion (11a) to form a stripline monitor, with the stripline length being the same as the gap enclosure length.

  1. Positioning of Embedded Optical Fibres Sensors for the Monitoring of Buckling in Stiffened Composite Panels

    NASA Astrophysics Data System (ADS)

    Riccio, A.; Di Caprio, F.; Camerlingo, F.; Scaramuzzino, F.; Gambino, B.

    2013-02-01

    A numerical/experimental study on the monitoring of the skin buckling phenomenon in stiffened composite panels by embedding optical fibres is presented in this paper. A numerical procedure has been introduced able to provide the most efficient embedded optical fibre path (with minimum length) fulfilling the grating sensors locations and directions requirements whilst satisfying specific embedding/integrity constraints for the optical fibre. The developed numerical procedure has been applied to a stiffened composite panel under compression load. The best location and direction of the grating sensors and the optimal optical fibre path for the monitoring of the skin buckling phenomenon have been found by performing respectively non-linear FEM analyses and optimization analyses. The procedure has been validated by means of an experimental testing activity on a stiffened panel instrumented with embedded optical fibres and back-to-back strain gauges which have been positioned according to the numerically estimated grating sensors locations and directions.

  2. Design and simulation of a wire position monitor for cryogenic systems in an ADS linac

    NASA Astrophysics Data System (ADS)

    Zhu, Hong-Yan; Dong, Lan; Li, Bo

    2014-08-01

    This paper introduces the design and simulation of a Wire Position Monitor (WPM) used in the cryogenic system of an Accelerator Driven System (ADS). The WPM is designed to monitor the contraction of cold masses during the cooling-down operation. In this paper, POISSON-2D electrostatic field software is used to calculate the best characteristic impedance for the WPM. Furthermore, the time domain signal of different end structures is theoretically analyzed and simulated. The coupling of electrodes and the influence of signal carrier size, which may influence the induced signal, are also discussed. Finally, the linearity of the induced voltage and the sensitivity of the WPM are analyzed. The time domain simulation results are consistent with the theoretical analysis. The influences of the coupling and carrier size are very small, and the linearity of the normalized voltage is good within r/2.

  3. Real-Time Target Position Estimation Using Stereoscopic Kilovoltage/Megavoltage Imaging and External Respiratory Monitoring for Dynamic Multileaf Collimator Tracking

    SciTech Connect

    Cho, Byungchul; Poulsen, Per Rugaard; Sawant, Amit; Ruan, Dan; Keall, Paul J.

    2011-01-01

    Purpose: To develop a real-time target position estimation method using stereoscopic kilovoltage (kV)/megavoltage (MV) imaging and external respiratory monitoring, and to investigate the performance of a dynamic multileaf collimator tracking system using this method. Methods and Materials: The real-time three-dimensional internal target position estimation was established by creating a time-varying correlation model that connected the external respiratory signals with the internal target motion measured intermittently using kV/MV imaging. The method was integrated into a dynamic multileaf collimator tracking system. Tracking experiments were performed for 10 thoracic/abdominal traces. A three-dimensional motion platform carrying a gold marker and a separate one-dimensional motion platform were used to reproduce the target and external respiratory motion, respectively. The target positions were detected by kV (1 Hz) and MV (5.2 Hz) imaging, and external respiratory motion was captured by an optical system (30 Hz). The beam-target alignment error was quantified as the positional difference between the target and circular beam center on the MV images acquired during tracking. The correlation model error was quantified by comparing a model estimate and measured target positions. Results: The root-mean-square errors in the beam-target alignment that had ranged from 3.1 to 7.6 mm without tracking were reduced to <1.5 mm with tracking, except during the model building period (6 s). The root-mean-square error in the correlation model was submillimeters in all directions. Conclusion: A novel real-time target position estimation method was developed and integrated into a dynamic multileaf collimator tracking system and demonstrated an average submillimeter geometric accuracy after initializing the internal/external correlation model. The method used hardware tools available on linear accelerators and therefore shows promise for clinical implementation.

  4. Progress in KEKB beam instrumentation systems

    NASA Astrophysics Data System (ADS)

    Arinaga, Mitsuhiro; Flanagan, John W.; Fukuma, Hitoshi; Furuya, Takaaki; Hiramatsu, Shigenori; Ikeda, Hitomi; Ishii, Hitoshi; Kikutani, Eiji; Mitsuhashi, Toshiyuki; Mori, Kenji; Tejima, Masaki; Tobiyama, Makoto

    2013-03-01

    The paper describes several topics relating to the beam instrumentation systems at the KEKB B-factory (KEKB) from 2003 to the end of its operation. It covers 1) measurement of the tilt angle of a bunch caused by a crab cavity, 2) a diagnostic system for beam aborts, 3) bunch feedback and related systems, and 4) progress in the beam position monitor system.

  5. [Metastatic castration-resistant prostate cancer: position paper for structured therapy monitoring].

    PubMed

    Miller, K; Albers, P; Eichenauer, R; Geiges, G; Grimm, M-O; König, F; Mickisch, G; Pfister, D; Schwentner, C; Suttmann, H; Zastrow, S

    2014-05-01

    This position paper is intended to help to structure and to standardize therapy monitoring in patients with metastatic castration-resistant prostate cancer (mCRPC). With the treatment options available today, patients with metastatic disease can often maintain good quality of life and stable disease for several years. It is crucial that once a therapy becomes insufficiently effective that it be replaced in a timely manner by a new treatment option. From a prognostic point of view, it is important that patients receive as many as possible and in the ideal case all currently available treatment options.

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

    PubMed Central

    Paknahad, Maryam; Shahidi, Shoaleh; Iranpour, Shiva; Mirhadi, Sabah; Paknahad, Majid

    2015-01-01

    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. PMID:26681944

  7. High precision beam alignment of electromagnetic wigglers

    SciTech Connect

    Ben-Zvi, I.; Qiu, X.Z.

    1993-01-01

    The performance of Free-Electron Lasers depends critically on the quality of the alignment of the electron beam to the wiggler's magnetic axis and the deviation of this axis from a straight fine. The measurement of the electron beam position requires numerous beam position monitors in the wiggler, where space is at premium. The beam position measurement is used to set beam steerers for an orbit correction in the wiggler. The authors propose an alternative high precision alignment method in which one or two external Beam Position Monitors (BPM) are used. In this technique, the field in the electro-wiggler is modulated section by section and the beam position movement at the external BPM is detected in synchronism with the modulation. A beam offset at the modulated beam section will produce a modulation of the beam position at the detector that is a function of the of the beam offset and the absolute value of the modulation current. The wiggler errors produce a modulation that is a function of the modulation current. It will be shown that this method allows the detection and correction of the beam position at each section in the presence of wiggler errors with a good resolution. Furthermore, it allows one to measure the first and second integrals of the wiggler error over each wiggler section. Lastly, provided that wiggler sections can be degaussed effectively, one can test the deviation of the wiggler's magnetic axis from a straight line.

  8. SU-E-J-62: Breath Hold for Left-Sided Breast Cancer: Visually Monitored Deep Inspiration Breath Hold Amplitude Evaluated Using Real-Time Position Management

    SciTech Connect

    Conroy, L; Quirk, S; Smith, WL; Yeung, R; Phan, T; Hudson, A

    2015-06-15

    Purpose: We used Real-Time Position Management (RPM) to evaluate breath hold amplitude and variability when gating with a visually monitored deep inspiration breath hold technique (VM-DIBH) with retrospective cine image chest wall position verification. Methods: Ten patients with left-sided breast cancer were treated using VM-DIBH. Respiratory motion was passively collected once weekly using RPM with the marker block positioned at the xiphoid process. Cine images on the tangent medial field were acquired on fractions with RPM monitoring for retrospective verification of chest wall position during breath hold. The amplitude and duration of all breath holds on which treatment beams were delivered were extracted from the RPM traces. Breath hold position coverage was evaluated for symmetric RPM gating windows from ± 1 to 5 mm centered on the average breath hold amplitude of the first measured fraction as a baseline. Results: The average (range) breath hold amplitude and duration was 18 mm (3–36 mm) and 19 s (7–34 s). The average (range) of amplitude standard deviation per patient over all breath holds was 2.7 mm (1.2–5.7 mm). With the largest allowable RPM gating window (± 5 mm), 4 of 10 VM-DIBH patients would have had ≥ 10% of their breath hold positions excluded by RPM. Cine verification of the chest wall position during the medial tangent field showed that the chest wall was greater than 5 mm from the baseline in only 1 out of 4 excluded patients. Cine images verify the chest wall/breast position only, whether this variation is acceptable in terms of heart sparing is a subject of future investigation. Conclusion: VM-DIBH allows for greater breath hold amplitude variability than using a 5 mm gating window with RPM, while maintaining chest wall positioning accuracy within 5 mm for the majority of patients.

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

    NASA Astrophysics Data System (ADS)

    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.

  10. Experimental validation of the dual positive and negative ion beam acceleration in the plasma propulsion with electronegative gases thruster

    SciTech Connect

    Rafalskyi, Dmytro Popelier, Lara; Aanesland, Ane

    2014-02-07

    The PEGASES (Plasma Propulsion with Electronegative Gases) thruster is a gridded ion thruster, where both positive and negative ions are accelerated to generate thrust. In this way, additional downstream neutralization by electrons is redundant. To achieve this, the thruster accelerates alternately positive and negative ions from an ion-ion plasma where the electron density is three orders of magnitude lower than the ion densities. This paper presents a first experimental study of the alternate acceleration in PEGASES, where SF{sub 6} is used as the working gas. Various electrostatic probes are used to investigate the source plasma potential and the energy, composition, and current of the extracted beams. We show here that the plasma potential control in such system is key parameter defining success of ion extraction and is sensitive to both parasitic electron current paths in the source region and deposition of sulphur containing dielectric films on the grids. In addition, large oscillations in the ion-ion plasma potential are found in the negative ion extraction phase. The oscillation occurs when the primary plasma approaches the grounded parts of the main core via sub-millimetres technological inputs. By controlling and suppressing the various undesired effects, we achieve perfect ion-ion plasma potential control with stable oscillation-free operation in the range of the available acceleration voltages (±350 V). The measured positive and negative ion currents in the beam are about 10 mA for each component at RF power of 100 W and non-optimized extraction system. Two different energy analyzers with and without magnetic electron suppression system are used to measure and compare the negative and positive ion and electron fluxes formed by the thruster. It is found that at alternate ion-ion extraction the positive and negative ion energy peaks are similar in areas and symmetrical in position with +/− ion energy corresponding to the amplitude of the applied

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

    NASA Astrophysics Data System (ADS)

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

    2015-05-01

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

  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

    SciTech Connect

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

    NASA Astrophysics Data System (ADS)

    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.

  14. Positioning Errors of Pencil-beam Interferometers for Long TraceProfilers

    SciTech Connect

    Yashchuk, Valeriy V.

    2006-07-12

    We analyze the random noise and the systematic errors of the positioning of the interference patterns in the long trace profilers (LTP). The analysis, based on linear regression methods, allows the estimation of the contributions to the positioning error of a number of effects, including non-uniformity of the detector photo-response and pixel pitch, read-out and dark signal noise, ADC resolution, as well as signal shot noise. The dependence of the contributions on pixel size and on total number of pixels involved in positioning is derived analytically. The analysis, when applied to the LTP II available at the ALS optical metrology laboratory, has shown that the main source for the random positioning error of the interference pattern is the read-out noise estimated to be {approx}0.2 rad. The photo-diode-array photo-response and pixel pitch non-uniformity determine the magnitude of the systematic positioning error and are found to be {approx}0.3 rad for each of the effects. Recommendations for an optimal fitting strategy, detector selection and calibration are provided. Following these recommendations will allow the reduction of the error of LTP interference pattern positioning to a level adequate for the slope measurement with 0.1-rad accuracy.

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

    SciTech Connect

    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.

  16. Commissioning of an Integrated Platform for Time-Resolved Treatment Delivery in Scanned Ion Beam Therapy by Means of Optical Motion Monitoring

    PubMed Central

    Fattori, G.; Saito, N.; Seregni, M.; Kaderka, R.; Pella, A.; Constantinescu, A.; Riboldi, M.; Steidl, P.; Cerveri, P.; Bert, C.; Durante, M.; Baroni, G.

    2014-01-01

    The integrated use of optical technologies for patient monitoring is addressed in the framework of time-resolved treatment delivery for scanned ion beam therapy. A software application has been designed to provide the therapy control system (TCS) with a continuous geometrical feedback by processing the external surrogates tridimensional data, detected in real-time via optical tracking. Conventional procedures for phase-based respiratory phase detection were implemented, as well as the interface to patient specific correlation models, in order to estimate internal tumor motion from surface markers. In this paper, particular attention is dedicated to the quantification of time delays resulting from system integration and its compensation by means of polynomial interpolation in the time domain. Dedicated tests to assess the separate delay contributions due to optical signal processing, digital data transfer to the TCS and passive beam energy modulation actuation have been performed. We report the system technological commissioning activities reporting dose distribution errors in a phantom study, where the treatment of a lung lesion was simulated, with both lateral and range beam position compensation. The zero-delay systems integration with a specific active scanning delivery machine was achieved by tuning the amount of time prediction applied to lateral (14.61 ± 0.98 ms) and depth (34.1 ± 6.29 ms) beam position correction signals, featuring sub-millimeter accuracy in forward estimation. Direct optical target observation and motion phase (MPh) based tumor motion discretization strategies were tested, resulting in −0.3(2.3)% and −1.2(9.3)% median (IQR) percentual relative dose difference with respect to static irradiation, respectively. Results confirm the technical feasibility of the implemented strategy towards 4D treatment delivery, with negligible percentual dose deviations with respect to static irradiation. PMID:24354750

  17. Positioning Multiple Proteins at the Nanoscale with Electron Beam Cross-Linked Functional Polymers

    PubMed Central

    Christman, Karen L.; Schopf, Eric; Broyer, Rebecca M.; Li, Ronald C.; Chen, Yong; Maynard, Heather D.

    2009-01-01

    Constructing multicomponent protein structures that match the complexity of those found in Nature is essential for the next generation of medical materials. In this report, a versatile method to precisely arrange multicomponent protein nanopatterns in two-dimensional single-layer or three-dimensional multilayer formats using electron beam lithography is described. Eight arm poly(ethylene glycol)s were modified at the chain ends with either biotin, maleimide, aminooxy, or nitrilotriacetic acid. Analysis by 1H NMR spectroscopy revealed that the reactions were efficient and that end group conversions were 91-100%. The polymers were then cross-linked onto Si surfaces using electron beams to form micron sized patterns of the functional groups. Proteins with biotin binding sites, a free cysteine, an N-terminal α-oxoamide, and a histidine tag, respectively, were then incubated with the substrate in aqueous solutions without the addition of any other reagents. By fluorescence microscopy experiments it was determined that proteins reacted site-specifically with the exposed functional groups to form protein micropatterns. Multicomponent nanoscale protein patterns were then fabricated. Different PEGs with orthogonal reactivity were sequentially patterned on the same chip. Simultaneous assembly of two different proteins from a mixture of the biomolecules formed the multicomponent two dimensional patterns. Atomic force microscopy demonstrated that nanometer sized patterns of polymer were formed and fluorescence microscopy demonstrated that side-by-side patterns of the different proteins were obtained. Moreover, multilayer PEG fabrication produced micron and nanometer sized patterns of one functional group on top of the other. Precise three-dimensional arrangements of different proteins were then realized. PMID:19160460

  18. Proposing a Laser Based Beam Size Monitor for the Future Linear Collider

    SciTech Connect

    Ross, Marc C

    2001-12-10

    Compton scattering techniques for the measurement of the transverse beam size of particle beams at future linear colliders (FLC) are proposed. At several locations of the beam delivery system (BDS) of the FLC, beam spot sizes ranging from several hundreds to a few micrometers have to be measured. This is necessary to verify beam optics, to obtain the transverse beam emittance, and to achieve the highest possible luminosity. The large demagnification of the beam in the BDS and the high beam power puts extreme conditions on any measuring device. With conventional techniques at their operational limit in FLC scenarios, new methods for the detection of the transverse beam size have to be developed. For this laser based techniques are proposed capable of measuring high power beams with sizes in the micrometer range. In this paper general aspects and critical issues of a generic device are outlined and specific solutions proposed. Plans to install a laser wire experiment at an accelerator test facility are presented.

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

    NASA Technical Reports Server (NTRS)

    Lyle, Karen H.; Vassilakos, Gregory J.

    2015-01-01

    This report summarizes the initial modeling of the global response of the Bigelow Expandable Activity Module (BEAM) to micrometeorite and orbital debris(MMOD) impacts using a structural, nonlinear, transient dynamic, finite element code. These models complement the on-orbit deployment of the Distributed Impact Detection System (DIDS) to support structural health monitoring studies. Two global models were developed. The first focused exclusively on impacts on the soft-goods (fabric-envelop) portion of BEAM. The second incorporates the bulkhead to support understanding of bulkhead impacts. These models were exercised for random impact locations and responses monitored at the on-orbit sensor locations. The report concludes with areas for future study.

  20. Performance of Advanced Light Source particle beam diagnostics

    SciTech Connect

    Hinkson, J.

    1993-05-01

    The Advanced Light Source (ALS), a third-generation synchrotron radiation facility, is complete. The particle beam diagnostics have been installed and tested. The beam injection systems have been running for two years. We have performance data on beam position monitors, beam intensity monitors, scintillators, beam collimators, a 50 {Omega} Faraday cup, and broad-band striplines and kickers used in the linac, transport lines, and the booster synchrotron. The single-turn monitoring capability of the booster beam position monitoring system has been particularly useful for studying beam dynamics. Beam diagnostics for the storage ring are being commissioned. In this paper we describe each instrument, show its performance, and outline how the instruments are controlled and their output data displayed.

  1. BEAM DIAGNOSTICS USING BPM SIGNALS FROM INJECTED AND STORED BEAMS IN A STORAGE RING

    SciTech Connect

    Wang, G.M.; Shaftan; T.; Cheng; W.X.; Fliller; R.; Heese; R.; Singh; O.; Willeke; F.

    2011-03-28

    Many modern light sources are operating in top-off injection mode or are being upgraded to top-off injection mode. The storage ring always has the stored beam and injected beam for top-off injection mode. So the BPM data is the mixture of both beam positions and the injected beam position cannot be measured directly. We propose to use dedicated wide band BPM electronics in the NSLS II storage ring to retrieve the injected beam trajectory with the singular value decomposition (SVD) method. The beam position monitor (BPM) has the capability to measure bunch-by-bunch beam position. Similar electronics can be used to measure the bunch-by-bunch beam current which is necessary to get the injection beam position. The measurement precision of current needs to be evaluated since button BPM sum signal has position dependence. The injected beam trajectory can be measured and monitored all the time without dumping the stored beam. We can adjust and optimize the injected beam trajectory to maximize the injection efficiency. We can also measure the storage ring acceptance by mapping the injected beam trajectory.

  2. Positive end-expiratory pressure oscillation facilitates brain vascular reactivity monitoring.

    PubMed

    Brady, Ken M; Easley, R Blaine; Kibler, Kathleen; Kaczka, David W; Andropoulos, Dean; Fraser, Charles D; Smielewski, Peter; Czosnyka, Marek; Adams, Gerald J; Rhee, Christopher J; Rusin, Craig G

    2012-11-01

    The pressure reactivity index (PRx) identifies optimal cerebral perfusion pressure after traumatic brain injury. We describe a method to improve PRx precision by induced variations in arterial blood pressure (ABP) using positive end-expiratory pressure (PEEP) modulation (iPRx). Neonatal swine (n = 10) were ventilated with static PEEP and then with PEEP oscillated between 5 and 10 cmH(2)O at a frequency of 1/min. PRx was recorded as a moving correlation coefficient between ABP and intracranial pressure (ICP) from spontaneous ABP activity (0.05-0.003 Hz) during static PEEP. iPRx was similarly recorded with PEEP oscillation-induced ABP waves. The lower limit of autoregulation (LLA) was delineated with continuous cortical laser Doppler flux monitoring. PEEP oscillation increased autoregulation-monitoring precision. The ratios of median absolute deviations to range of possible values for the PRx and iPRx were 9.5% (8.3-13.7%) and 6.2% (4.2-8.7%), respectively (P = 0.006; median, interquartile range). The phase-angle difference between ABP and ICP above LLA was 161° (150°-166°) and below LLA, -31° (-42° to 12°, P < 0.0001). iPRx above LLA was -0.42 (-0.67 to -0.29) and below LLA, 0.32 (0.22-0.43, P = 0.0004). A positive iPRx was 97% specific and 91% sensitive for perfusion pressure below LLA. PEEP oscillation caused stable, low-frequency ABP oscillations that reduced noise in the PRx. Safe translation of these findings to clinical settings is expected to yield more accurate and rapid delineation of individualized optimal perfusion-pressure goals for patients.

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

    PubMed

    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.

  4. Absolute prompt-gamma yield measurements for ion beam therapy monitoring.

    PubMed

    Pinto, M; Bajard, M; Brons, S; Chevallier, M; Dauvergne, D; Dedes, G; De Rydt, M; Freud, N; Krimmer, J; La Tessa, C; Létang, J M; Parodi, K; Pleskač, R; Prieels, D; Ray, C; Rinaldi, I; Roellinghoff, F; Schardt, D; Testa, E; Testa, M

    2015-01-21

    Prompt-gamma emission detection is a promising technique for hadrontherapy monitoring purposes. In this regard, obtaining prompt-gamma yields that can be used to develop monitoring systems based on this principle is of utmost importance since any camera design must cope with the available signal. Herein, a comprehensive study of the data from ten single-slit experiments is presented, five consisting in the irradiation of either PMMA or water targets with lower and higher energy carbon ions, and another five experiments using PMMA targets and proton beams. Analysis techniques such as background subtraction methods, geometrical normalization, and systematic uncertainty estimation were applied to the data in order to obtain absolute prompt-gamma yields in units of prompt-gamma counts per incident ion, unit of field of view, and unit of solid angle. At the entrance of a PMMA target, where the contribution of secondary nuclear reactions is negligible, prompt-gamma counts per incident ion, per millimetre and per steradian equal to (124 ± 0.7stat ± 30sys) × 10(-6) for 95 MeV u(-1) carbon ions, (79 ± 2stat ± 23sys) × 10(-6) for 310 MeV u(-1) carbon ions, and (16 ± 0.07stat ± 1sys) × 10(-6) for 160 MeV protons were found for prompt gammas with energies higher than 1 MeV. This shows a factor 5 between the yields of two different ions species with the same range in water (160 MeV protons and 310 MeV u(-1) carbon ions). The target composition was also found to influence the prompt-gamma yield since, for 300/310 MeV u(-1) carbon ions, a 42% greater yield ((112 ± 1stat ± 22sys) × 10(-6) counts ion(-1) mm(-1) sr(-1)) was obtained with a water target compared to a PMMA one. PMID:25548833

  5. Positioning accuracy of cone-beam computed tomography in combination with a HexaPOD robot treatment table

    SciTech Connect

    Meyer, Juergen . E-mail: juergen.meyer@canterbury.ac.nz; Wilbert, Juergen; Baier, Kurt; Guckenberger, Matthias; Richter, Anne; Sauer, Otto; Flentje, Michael

    2007-03-15

    Purpose: To scrutinize the positioning accuracy and reproducibility of a commercial hexapod robot treatment table (HRTT) in combination with a commercial cone-beam computed tomography system for image-guided radiotherapy (IGRT). Methods and Materials: The mechanical stability of the X-ray volume imaging (XVI) system was tested in terms of reproducibility and with a focus on the moveable parts, i.e., the influence of kV panel and the source arm on the reproducibility and accuracy of both bone and gray value registration using a head-and-neck phantom. In consecutive measurements the accuracy of the HRTT for translational, rotational, and a combination of translational and rotational corrections was investigated. The operational range of the HRTT was also determined and analyzed. Results: The system performance of the XVI system alone was very stable with mean translational and rotational errors of below 0.2 mm and below 0.2{sup o}, respectively. The mean positioning accuracy of the HRTT in combination with the XVI system summarized over all measurements was below 0.3 mm and below 0.3{sup o} for translational and rotational corrections, respectively. The gray value match was more accurate than the bone match. Conclusion: The XVI image acquisition and registration procedure were highly reproducible. Both translational and rotational positioning errors can be corrected very precisely with the HRTT. The HRTT is therefore well suited to complement cone-beam computed tomography to take full advantage of position correction in six degrees of freedom for IGRT. The combination of XVI and the HRTT has the potential to improve the accuracy of high-precision treatments.

  6. Monitoring of transverse displacement of reinforced concrete beams under flexural loading with embedded arrays of optical fibers

    NASA Astrophysics Data System (ADS)

    Gonzalez-Tinoco, Juan E.; Gomez-Rosas, Enrique R.; Guzmán-Olguín, Héctor; Khotiaintsev, Sergei; Zuñiga-Bravo, Miguel A.

    2015-04-01

    We present results of an ongoing study of structural health monitoring of concrete elements by means of arrays of telecommunications-grade optical fibers embedded in such elements. In this work, we show a possibility of using this technique for monitoring the transverse displacement of the reinforced concrete beams under flexural loading. We embedded a number of multimode silica-core/polymer-clad/polymer-coated optical fibers in a mold with preinstalled reinforcing steel bars and fresh concrete mix. Then the concrete was compacted and cured. Some optical fibers were broken during the fabrication process. The fiber survival rate varied with concrete grade, compacting technique and optical fiber type. The fibers that survived the fabrication process were employed for the monitoring. They were connected to the optical transmitter and receiver that formed a part of a larger measurement system. The system continuously measured the optical transmission of all optical fibers while the reinforced concrete beams were subjected to incremental transverse loading. We observed a quasi-linear decrease in optical transmission in all optical fibers of the array vs. the applied load and respective flexural displacement. Although the underlying phenomena that lead to such a variation in optical transmission are not clear yet, the observed behavior might be of interest for assessing the transverse displacement of the reinforced concrete beams under flexural loading.

  7. A computer algorithm for automatic beam steering

    SciTech Connect

    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.

  8. Beam Diagnostics for FACET

    SciTech Connect

    Li, S.Z.; Hogan, M.J.; /SLAC

    2011-08-19

    FACET, the Facility for Advanced Accelerator and Experimental Tests, is a new facility being constructed in sector 20 of the SLAC linac primarily to study beam driven plasma wakefield acceleration beginning in summer 2011. The nominal FACET parameters are 23GeV, 3nC electron bunches compressed to about 20 {micro}m long and focussed to about 10 {micro}m wide. Characterization of the beam-plasma interaction requires complete knowledge of the incoming beam parameters on a pulse-to-pulse basis. FACET diagnostics include Beam Position Monitors, Toroidal current monitors, X-ray and Cerenkov based energy spectrometers, optical transition radiation (OTR) profile monitors and coherent transition radiation (CTR) bunch length measurement systems. The compliment of beam diagnostics and their expected performance are reviewed. Beam diagnostic measurements not only provide valuable insights to the running and tuning of the accelerator but also are crucial for the PWFA experiments in particular. Beam diagnostic devices are being set up at FACET and will be ready for beam commissioning in summer 2011.

  9. Monitor unit calculations for external photon and electron beams: Report of the AAPM Therapy Physics Committee Task Group No. 71.

    PubMed

    Gibbons, John P; Antolak, John A; Followill, David S; Huq, M Saiful; Klein, Eric E; Lam, Kwok L; Palta, Jatinder R; Roback, Donald M; Reid, Mark; Khan, Faiz M

    2014-03-01

    A protocol is presented for the calculation of monitor units (MU) for photon and electron beams, delivered with and without beam modifiers, for constant source-surface distance (SSD) and source-axis distance (SAD) setups. This protocol was written by Task Group 71 of the Therapy Physics Committee of the American Association of Physicists in Medicine (AAPM) and has been formally approved by the AAPM for clinical use. The protocol defines the nomenclature for the dosimetric quantities used in these calculations, along with instructions for their determination and measurement. Calculations are made using the dose per MU under normalization conditions, D'0, that is determined for each user's photon and electron beams. For electron beams, the depth of normalization is taken to be the depth of maximum dose along the central axis for the same field incident on a water phantom at the same SSD, where D'0 = 1 cGy/MU. For photon beams, this task group recommends that a normalization depth of 10 cm be selected, where an energy-dependent D'0 ≤ 1 cGy/MU is required. This recommendation differs from the more common approach of a normalization depth of dm, with D'0 = 1 cGy/MU, although both systems are acceptable within the current protocol. For photon beams, the formalism includes the use of blocked fields, physical or dynamic wedges, and (static) multileaf collimation. No formalism is provided for intensity modulated radiation therapy calculations, although some general considerations and a review of current calculation techniques are included. For electron beams, the formalism provides for calculations at the standard and extended SSDs using either an effective SSD or an air-gap correction factor. Example tables and problems are included to illustrate the basic concepts within the presented formalism.

  10. Design, installation, commissioning and operation of a beamlet monitor in the negative ion beam test stand at NIFS

    SciTech Connect

    Antoni, V.; Agostinetti, P.; Brombin, M.; Cervaro, V.; Delogu, R.; Fasolo, D.; Franchin, L.; Ghiraldelli, R.; Molon, F.; Pasqualotto, R.; Serianni, G. Tollin, M.; Veltri, P.; De Muri, M.; Ikeda, K.; Kisaki, M.; Nakano, H.; Takeiri, Y.; Tsumori, K.; Muraro, A.

    2015-04-08

    In the framework of the accompanying activity for the development of the two neutral beam injectors for the ITER fusion experiment, an instrumented beam calorimeter is being designed at Consorzio RFX, to be used in the SPIDER test facility (particle energy 100keV; beam current 50A), with the aim of testing beam characteristics and to verify the source proper operation. The main components of the instrumented calorimeter are one-directional carbon-fibre-carbon composite tiles. Some prototype tiles have been used as a small-scale version of the entire calorimeter in the test stand of the neutral beam injectors of the LHD experiment, with the aim of characterising the beam features in various operating conditions. The extraction system of the NIFS test stand source was modified, by applying a mask to the first gridded electrode, in order to isolate only a subset of the beamlets, arranged in two 3×5 matrices, resembling the beamlet groups of the ITER beam sources. The present contribution gives a description of the design of the diagnostic system, including the numerical simulations of the expected thermal pattern. Moreover the dedicated thermocouple measurement system is presented. The beamlet monitor was successfully used for a full experimental campaign, during which the main parameters of the source, mainly the arc power and the grid voltages, were varied. This contribution describes the methods of fitting and data analysis applied to the infrared images of the camera to recover the beamlet optics characteristics, in order to quantify the response of the system to different operational conditions. Some results concerning the beamlet features are presented as a function of the source parameters.

  11. Monitor unit calculations for external photon and electron beams: Report of the AAPM Therapy Physics Committee Task Group No. 71

    SciTech Connect

    Gibbons, John P.; Antolak, John A.; Followill, David S.; Huq, M. Saiful; Klein, Eric E.; Lam, Kwok L.; Palta, Jatinder R.; Roback, Donald M.; Reid, Mark; Khan, Faiz M.

    2014-03-15

    A protocol is presented for the calculation of monitor units (MU) for photon and electron beams, delivered with and without beam modifiers, for constant source-surface distance (SSD) and source-axis distance (SAD) setups. This protocol was written by Task Group 71 of the Therapy Physics Committee of the American Association of Physicists in Medicine (AAPM) and has been formally approved by the AAPM for clinical use. The protocol defines the nomenclature for the dosimetric quantities used in these calculations, along with instructions for their determination and measurement. Calculations are made using the dose per MU under normalization conditions, D{sub 0}{sup ′}, that is determined for each user's photon and electron beams. For electron beams, the depth of normalization is taken to be the depth of maximum dose along the central axis for the same field incident on a water phantom at the same SSD, where D{sub 0}{sup ′} = 1 cGy/MU. For photon beams, this task group recommends that a normalization depth of 10 cm be selected, where an energy-dependent D{sub 0}{sup ′} ≤ 1 cGy/MU is required. This recommendation differs from the more common approach of a normalization depth of d{sub m}, with D{sub 0}{sup ′} = 1 cGy/MU, although both systems are acceptable within the current protocol. For photon beams, the formalism includes the use of blocked fields, physical or dynamic wedges, and (static) multileaf collimation. No formalism is provided for intensity modulated radiation therapy calculations, although some general considerations and a review of current calculation techniques are included. For electron beams, the formalism provides for calculations at the standard and extended SSDs using either an effective SSD or an air-gap correction factor. Example tables and problems are included to illustrate the basic concepts within the presented formalism.

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

    PubMed Central

    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 breast cancer patients. The median prescription dose to the optimized planning target volume (PTVoptim) was 50 Gy in 25 fractions. Dose-volume parameters and indices of conformity were calculated for the PTVoptim and organs-at-risk. Results Prone MB-IMRT achieved (p<0.01) the best dose homogeneity compared to WTF in the prone position and WTF and MB-IMRT in the supine position. Prone IMRT scored better for all dose indices. MB-IMRT lowered lung and heart dose (p<0.05) in supine position, however the lowest ipsilateral lung doses (p<0.001) were in prone position. In left-sided breast cancer patients population averages for heart sparing by radiation dose was better in prone position; though non-significant. For patients with a PTVoptim volume ≥600 cc heart dose was consistently lower in prone position; while for patients with smaller breasts heart dose metrics were comparable or worse compared to supine MB-IMRT. Doses to the contralateral breast were similar regardless of position or technique. Dosimetry of prone MB-IMRT and prone TF-IMRT differed slightly. Conclusions MB-IMRT is the treatment of choice in supine position. Prone IMRT is superior to any supine treatment for right-sided breast cancer patients and left-sided breast cancer patients with larger breasts by obtaining better conformity indices, target dose distribution and sparing of the organs-at-risk. The influence of treatment techniques in prone position is less pronounced; moreover dosimetric differences between TF

  13. Design and characterization of the beam monitor detectors of the Italian National Center of Oncological Hadron-therapy (CNAO)

    NASA Astrophysics Data System (ADS)

    Giordanengo, S.; Donetti, M.; Garella, M. A.; Marchetto, F.; Alampi, G.; Ansarinejad, A.; Monaco, V.; Mucchi, M.; Pecka, I. A.; Peroni, C.; Sacchi, R.; Scalise, M.; Tomba, C.; Cirio, R.

    2013-01-01

    A new hadron-therapy facility implementing an active beam scanning technique has been developed at the Italian National Center of Oncological Hadron-therapy (CNAO). This paper presents the design and the characterization of the beam monitor detectors developed for the on-line monitoring and control of the dose delivered during a treatment at CNAO. The detectors are based on five parallel-plate transmission ionization chambers with either a single large electrode or electrodes segmented in 128 strips (strip chambers) and 32×32 pixels (pixel chamber). The detectors are arranged in two independent boxes with an active area larger than 200×200 mm2 and a total water equivalent thickness along the beam path of about 0.9 mm. A custom front-end chip with 64 channels converts the integrated ionization channels without dead-time. The detectors were tested at the clinical proton beam facility of the Paul Scherrer Institut (PSI) which implements a spot scanning technique, each spot being characterized by a predefined number of protons delivered with a pencil beam in a specified point of the irradiation field. The short-term instability was measured by delivering several identical spots in a time interval of few tenths of seconds and is found to be lower than 0.3%. The non-uniformity, measured by delivering sequences of spots in different points of the detector surface, results to be lower than 1% in the single electrode chambers and lower than 1.5% in the strip and pixel chambers, reducing to less than 0.5% and 1% in the restricted 100×100 mm2 central area of the detector.

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

    NASA Astrophysics Data System (ADS)

    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.

  15. Automated Long-Term Monitoring of Parallel Microfluidic Operations Applying a Machine Vision-Assisted Positioning Method

    PubMed Central

    Yip, Hon Ming; Li, John C. S.; Cui, Xin; Gao, Qiannan; Leung, Chi Chiu

    2014-01-01

    As microfluidics has been applied extensively in many cell and biochemical applications, monitoring the related processes is an important requirement. In this work, we design and fabricate a high-throughput microfluidic device which contains 32 microchambers to perform automated parallel microfluidic operations and monitoring on an automated stage of a microscope. Images are captured at multiple spots on the device during the operations for monitoring samples in microchambers in parallel; yet the device positions may vary at different time points throughout operations as the device moves back and forth on a motorized microscopic stage. Here, we report an image-based positioning strategy to realign the chamber position before every recording of microscopic image. We fabricate alignment marks at defined locations next to the chambers in the microfluidic device as reference positions. We also develop image processing algorithms to recognize the chamber positions in real-time, followed by realigning the chambers to their preset positions in the captured images. We perform experiments to validate and characterize the device functionality and the automated realignment operation. Together, this microfluidic realignment strategy can be a platform technology to achieve precise positioning of multiple chambers for general microfluidic applications requiring long-term parallel monitoring of cell and biochemical activities. PMID:25133248

  16. Electrostatic pick-ups for debunched beams

    NASA Astrophysics Data System (ADS)

    Gavrilov, S.; Reinhardt-Nickoulin, P.; Vasilyev, I.

    2014-10-01

    Pick-ups are one of the most widespread non-destructive diagnostics at charged particle accelerators. These detectors, also known as beam position monitors, are generally used for the center-of-mass position measurements of bunched beams. The paper describes the research results for infrequent case of debunched coasting beams operation. Measurement peculiarities and distinctive features of electronics are presented. The results of test bench-based measurements and 3D finite element simulations are discussed.

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

    PubMed

    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.

  18. Physical activity intensity can be accurately monitored by smartphone global positioning system 'app'.

    PubMed

    Gordon, Brett Ashley; Bruce, Lyndell; Benson, Amanda Clare

    2016-08-01

    Monitoring physical activity is important to better individualise health and fitness benefits. This study assessed the concurrent validity of a smartphone global positioning system (GPS) 'app' and a sport-specific GPS device with a similar sampling rate, to measure physical activity components of speed and distance, compared to a higher sampling sport-specific GPS device. Thirty-eight (21 female, 17 male) participants, mean age of 24.68, s = 6.46 years, completed two 2.400 km trials around an all-weather athletics track wearing GPSports Pro™ (PRO), GPSports WiSpi™ (WISPI) and an iPhone™ with a Motion X GPS™ 'app' (MOTIONX). Statistical agreement, assessed using t-tests and Bland-Altman plots, indicated an (mean; 95% LOA) underestimation of 2% for average speed (0.126 km·h(-1); -0.389 to 0.642; p < .001), 1.7% for maximal speed (0.442 km·h(-1); -2.676 to 3.561; p = .018) and 1.9% for distance (0.045 km; -0.140 to 0.232; p < .001) by MOTIONX compared to that measured by PRO. In contrast, compared to PRO, WISPI overestimated average speed (0.232 km·h(-1); -0.376 to 0.088; p < .001) and distance (0.083 km; -0.129 to -0.038; p < .001) by 3.5% whilst underestimating maximal speed by 2.5% (0.474 km·h(-1); -1.152 to 2.099; p < .001). Despite the statistically significant difference, the MOTIONX measures intensity of physical activity, with a similar error as WISPI, to an acceptable level for population-based monitoring in unimpeded open-air environments. This presents a low-cost, minimal burden opportunity to remotely monitor physical activity participation to improve the prescription of exercise as medicine.

  19. Physical activity intensity can be accurately monitored by smartphone global positioning system 'app'.

    PubMed

    Gordon, Brett Ashley; Bruce, Lyndell; Benson, Amanda Clare

    2016-08-01

    Monitoring physical activity is important to better individualise health and fitness benefits. This study assessed the concurrent validity of a smartphone global positioning system (GPS) 'app' and a sport-specific GPS device with a similar sampling rate, to measure physical activity components of speed and distance, compared to a higher sampling sport-specific GPS device. Thirty-eight (21 female, 17 male) participants, mean age of 24.68, s = 6.46 years, completed two 2.400 km trials around an all-weather athletics track wearing GPSports Pro™ (PRO), GPSports WiSpi™ (WISPI) and an iPhone™ with a Motion X GPS™ 'app' (MOTIONX). Statistical agreement, assessed using t-tests and Bland-Altman plots, indicated an (mean; 95% LOA) underestimation of 2% for average speed (0.126 km·h(-1); -0.389 to 0.642; p < .001), 1.7% for maximal speed (0.442 km·h(-1); -2.676 to 3.561; p = .018) and 1.9% for distance (0.045 km; -0.140 to 0.232; p < .001) by MOTIONX compared to that measured by PRO. In contrast, compared to PRO, WISPI overestimated average speed (0.232 km·h(-1); -0.376 to 0.088; p < .001) and distance (0.083 km; -0.129 to -0.038; p < .001) by 3.5% whilst underestimating maximal speed by 2.5% (0.474 km·h(-1); -1.152 to 2.099; p < .001). Despite the statistically significant difference, the MOTIONX measures intensity of physical activity, with a similar error as WISPI, to an acceptable level for population-based monitoring in unimpeded open-air environments. This presents a low-cost, minimal burden opportunity to remotely monitor physical activity participation to improve the prescription of exercise as medicine. PMID:26505223

  20. Positioning effects on quantum dot solar cells grown by molecular beam epitaxy

    SciTech Connect

    Zhou, D.; Sharma, G.; Fimland, B. O.; Vullum, P. E.; Thomassen, S. F.; Holmestad, R.; Reenaas, T. W.

    2010-02-22

    We report current-voltage and spectral response characteristics of high density InAs/GaAs quantum dot (QD) solar cells with different positions where dots are located. The short circuit current density (J{sub sc}), open circuit voltage (V{sub oc}), and external quantum efficiency of these cells under air mass 1.5 are presented and compared with a GaAs reference cell. An extended photoresponse in contrast to the GaAs reference cell was confirmed for all these cells. The effect of inserting QD layers into emitter and base region on device performance is shown. The J{sub sc} is reduced, while the V{sub oc} is maintained. The cell with QDs located toward the base side shows better performance, confirmed by both current-voltage and spectral response measurements.