3D Terahertz Beam Profiling

DEFF Research Database (Denmark)

Pedersen, Pernille Klarskov; Strikwerda, Andrew; Jepsen, Peter Uhd

2013-01-01

We present a characterization of THz beams generated in both a two-color air plasma and in a LiNbO3 crystal. Using a commercial THz camera, we record intensity images as a function of distance through the beam waist, from which we extract 2D beam profiles and visualize our measurements into 3D beam...

Two-dimensional beam profiles and one-dimensional projections

Science.gov (United States)

Findlay, D. J. S.; Jones, B.; Adams, D. J.

2018-05-01

One-dimensional projections of improved two-dimensional representations of transverse profiles of particle beams are proposed for fitting to data from harp-type monitors measuring beam profiles on particle accelerators. Composite distributions, with tails smoothly matched on to a central (inverted) parabola, are shown to give noticeably better fits than single gaussian and single parabolic distributions to data from harp-type beam profile monitors all along the proton beam transport lines to the two target stations on the ISIS Spallation Neutron Source. Some implications for inferring beam current densities on the beam axis are noted.

Techniques for intense-proton-beam profile measurements

International Nuclear Information System (INIS)

Gilpatrick, J.D.

1998-01-01

In a collaborative effort with industry and several national laboratories, the Accelerator Production of Tritium (APT) facility and the Spallation Neutron Source (SNS) linac are presently being designed and developed at Los Alamos National Laboratory (LANL). The APT facility is planned to accelerate a 100-mA H + cw beam to 1.7 GeV and the SNS linac is planned to accelerate a 1- to 4-mA-average, H - , pulsed-beam to 1 GeV. With typical rms beam widths of 1- to 3-mm throughout much of these accelerators, the maximum average-power densities of these beams are expected to be approximately 30- and 1-MW-per-square millimeter, respectively. Such power densities are too large to use standard interceptive techniques typically used for acquisition of beam profile information. This paper summarizes the specific requirements for the beam profile measurements to be used in the APT, SNS, and the Low Energy Development Accelerator (LEDA)--a facility to verify the operation of the first 20-MeV section of APT. This paper also discusses the variety of profile measurement choices discussed at a recent high-average-current beam profile workshop held in Santa Fe, NM, and will present the present state of the design for the beam profile measurements planned for APT, SNS, and LEDA

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

Energy Technology Data Exchange (ETDEWEB)

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.

UV beam shaper alignment sensitivity: grayscale versus binary designs

Science.gov (United States)

Lizotte, Todd E.

2008-08-01

What defines a good flat top beam shaper? What is more important; an ideal flat top profile or ease of alignment and stability? These are the questions designers and fabricators can not easily define, since they are a function of experience. Anyone can generate a theoretical beam shaper design and model it until it is clear that on paper the design looks good and meets the general needs of the end customer. However, the method of fabrication can add a twist that is not fully understood by either party until the beam shaper is actually tested for the first time in a system and also produced in high volume. This paper provides some insight into how grayscale and binary fabrication methods can produce the same style of beam shaper, with similar beam shaping performance; however provide a result wherein each fabricated design has separate degrees of sensitivity for alignment and stability. The paper will explain the design and fabrication approach for the two units and present alignment and testing data to provide a contrast comparison. Further data will show that over twenty sets of each fabricated design there is a consistency to the sensitivity issue. An understanding of this phenomenon is essential when considering the use of beam shapers on production equipment that is dedicated to producing micron-precision features within high value microelectronic and consumer products. We will present our findings and explore potential explanations and solutions.

Beam profile monitors in the NLCTA

International Nuclear Information System (INIS)

Nantista, C.; Adolphsen, C.; Brown, R.L.; Fuller, R.; Rifkin, J.

1997-05-01

The transverse current profile in the Next Linear Collider Test Accelerator (NLCTA) electron beam can be monitored at several locations along the beam line by means of profile monitors. These consist of insertable phosphor screens, light collection and transport systems, CID cameras, a frame-grabber, and PC and VAX based image analysis software. In addition to their usefulness in tuning and steering the accelerator, the profile monitors are utilized for emittance measurement. A description of these systems and their performance is presented

Flying wire beam profile monitor at the J-PARC MR

International Nuclear Information System (INIS)

Igarashi, Susumu; Arakawa, Dai; Hashimoto, Yoshinori; Teshima, Masaki; Toyama, Takeshi; Hanamura, Kotoku

2008-01-01

A flying wire beam profile monitor has been assembled and installed at the main ring of the Japan Proton Accelerator Research Complex. The monitor is to measure the horizontal beam profile using a carbon fiber of 7 μmφ. The fiber crosses the beam with the speed of 10 m/s. Secondary particles from the beam-wire scattering is detected using a scintillation counter. The scintillator signal as a function of the wire position is to be reconstructed as a beam profile. The high scanning speed and the minimum material are necessary for the accurate beam profile measurement. The monitor has been operated in the beam commissioning run of the main ring. The beam profile data have been successfully acquired after the reduction of the beam background. (author)

GANIL beam profile detectors

International Nuclear Information System (INIS)

Tribouillard, C.

1997-01-01

In the design phase of GANIL which started in 1977, one of the priorities of the project management was equipping the beamlines with a fast and efficient system for visualizing the beam position, thus making possible adjustment of the beam transport lines optics and facilitating beam control. The implantation of some thirty detectors was foreseen in the initial design. The assembly of installed detectors (around 190) proves the advantages of these detectors for displaying all the beams extracted from GANIL: transfer and transport lines, beam extracted from SISSI, very high intensity beam, secondary ion beams from the production target of the LISE and SPEG spectrometers, different SPIRAL project lines. All of these detectors are based on standard characteristics: - standard flange diameter (DN 160) with a standard booster for all the sensors; - identical analog electronics for all the detectors, with networking; - unique display system. The new micro-channel plate non-interceptive detectors (beam profile and ion packet lengths) make possible in-line control of the beam quality and accelerator stability. (author)

Profile distortion by beam space-charge in Ionization Profile Monitors

CERN Document Server

Vilsmeier, D; Wettig, T

Measuring the transverse beam size in the Large Hadron Collider by using Ionization Profile Monitors is a difficult task for energies above injection during the energy ramp from 450 GeV to 6.5TeV. The beam size decreases from around 1mm to 200um and the brightness of the beam is high enough to destroy the structure of any form of interacting matter. While the electron trajectories are confined by an external electro-magnetic field which forces the electrons accordingly on helix paths with certain gyroradii, this gyration is heavily increased under the influence of the electric field of the beam. Smaller beam sizes, which go hand in hand with increased bunch electric fields, lead to larger gyroradii of the ionized electrons, which results in strongly distorted profiles. In addition, this distortion becomes more visible for smaller beam sizes as the extent of gyration grows compared to the actual beam size. Depending on the initial momentum distribution of the electrons, emerging from the ionization process wit...

Analytical & Experimental Study of Radio Frequency Cavity Beam Profile Monitor

Energy Technology Data Exchange (ETDEWEB)

Balcazar, Mario D. [Fermilab; Yonehara, Katsuya [Fermilab

2017-10-22

The purpose of this analytical and experimental study is multifold: 1) To explore a new, radiation-robust, hadron beam profile monitor for intense neutrino beam applications; 2) To test, demonstrate, and develop a novel gas-filled Radio-Frequency (RF) cavity to use in this monitoring system. Within this context, the first section of the study analyzes the beam distribution across the hadron monitor as well as the ion-production rate inside the RF cavity. Furthermore a more effecient pixel configuration across the hadron monitor is proposed to provide higher sensitivity to changes in beam displacement. Finally, the results of a benchtop test of the tunable quality factor RF cavity will be presented. The proposed hadron monitor configuration consists of a circular array of RF cavities located at a radial distance of 7cm { corresponding to the standard deviation of the beam due to scatering { and a gas-filled RF cavity with a quality factor in the range 400 - 800.

Beam profile monitor

International Nuclear Information System (INIS)

Krausse, G.J.; Gram, P.A.M.

1978-05-01

A system used to monitor secondary beam profiles at the LAMPF Linac for channel tune-up and diagnostics is described. The multiwire proportional chamber design is discussed, and descriptions and drawings of the gate card, the amplifier/multiplexer card, the output amplifier card, and the overall system are given

A webcam in Bayer-mode as a light beam profiler for the near infra-red.

Science.gov (United States)

Langer, Gregor; Hochreiner, Armin; Burgholzer, Peter; Berer, Thomas

2013-05-01

Beam profiles are commonly measured with complementary metal oxide semiconductors (CMOS) or charge coupled devices (CCD). The devices are fast and reliable but expensive. By making use of the fact that the Bayer-filter in commercial webcams is transparent in the near infra-red (>800 nm) and their CCD chips are sensitive up to about 1100 nm, we demonstrate a cheap and simple way to measure laser beam profiles with a resolution down to around ±1 μm, which is close to the resolution of the knife-edge technique.

Influence of laser beam profile on electromagnetically induced absorption

International Nuclear Information System (INIS)

Cuk, S. M.; Radonjic, M.; Krmpot, A. J.; Nikolic, S. N.; Grujic, Z. D.; Jelenkovic, B. M.

2010-01-01

We compared, experimentally and theoretically, Hanle electromagnetically induced absorption (EIA) obtained using Gaussian and Π-shaped laser beams 3 mm in diameter. The study was done by measuring the transmission of a laser locked to the F g =2→F e =3 transition at the D 2 line of 87 Rb in a vacuum cell. EIA linewidths obtained for the two laser profiles were significantly different in the range of laser intensities 1-4 mW/cm 2 . EIA with the Π-shaped laser beam has a broad intensity maximum and linewidths larger than those obtained with the Gaussian beam profile. We also studied Hanle EIA by measuring the transmission of selected segments of the entire laser beam by placing a small movable aperture in front of the detector. Waveforms so obtained in Hanle EIA resonances were strongly influenced both by the radial distance of the transmitted segment from the beam center and by the radial profile of the laser beam. We show that outer regions of Gaussian beam, and central regions of the Π-shaped beam generate the narrowest lines. The different behaviors of EIA owing to different beam profiles revealed by both theory and experiment indicate the importance of the radial profile of the laser beam for proper modeling of coherent effects in alkali metal vapors.

Beam profiles for fast neutrons; and reply

International Nuclear Information System (INIS)

Bewley, D.K.; Parnell, C.J.; Bloch, P.

1976-01-01

The authors express surprise that Bloch et al. (Bloch, P.H., Hendry, G.O., Hilton, J.L., Quam, W.M., Reinhard, D.K., and Wilson, C., 1976, Phys. Med. Biol., Vol. 21, 450) justified a target size of 5.5 x 5.5 cm in a neutron generator by comparison with the profile given by a 2.5 MV X-ray generator. The penumbral width of this new neutron generator is more than twice that of a modern megavoltage X-ray machine, and larger than those of beams from standard 60 Co units, or of the Hammersmith Hospital cyclotron beam. The large target size of the neutron generator may have to be accepted as a necessary evil, but should not be considered satisfactory. In reply, one of the authors of the original note presents the results of calculations of beam profiles for 14 MeV neutron beams in a tissue-equivalent phantom, and suggests that the broader profiles are principally caused by the larger probability of side scatter, not by source size. The most fruitful approach to sharpening the neutron beam profile would seem to be to design a field flattening filter to increase relative dose near the edge inside the geometrically defined field. Calculations indicating that Bewley and Parnell have underestimated the penumbral widths of 60 Co beams are also presented. (U.K.)

Measurement of neutral beam power and beam profile distribution on DNB

International Nuclear Information System (INIS)

Liu Zhimin; Liu Sheng; Song Shihua; Han Xiaopu; Li Jun; Hu Chundong; Hu Liqun; Xie Jun

2005-01-01

The injection power of a diagnostic neutral beam (DNB) can be obtained with the thermocouple probe measurement system on the Hefei superconducting Tokamak-7 (HT-7). With the 49 kv, 6 A, 100 ms pulse charge of an acceleration electrode, a thermocouple probe measurement system with 13 thermocouples crossly distributed on a coppery heat target was used to measure the temperature rise of the target, and the maximum measured temperature rise was 14 degree C. And the neutral beam power of 160 kW and beam profile distribution was obtained by calculation. The total neutral beam power of 130 kW was also obtained by integral calculation with the temperature rise on the heat section board. The difference between the two means was analyzed. The experiment results shows that the method of heat section board with thermocouple probe is one of the effective ways to measure the beam power and beam profile distribution. (authors)

Real-time beam profile imaging system for actinotherapy accelerator

International Nuclear Information System (INIS)

Lin Yong; Wang Jingjin; Song Zheng; Zheng Putang; Wang Jianguo

2003-01-01

This paper describes a real-time beam profile imaging system for actinotheraphy accelerator. With the flash X-ray imager and the technique of digital image processing, a real-time 3-dimension dosage image is created from the intensity profile of the accelerator beam in real time. This system helps to obtain all the physical characters of the beam in any section plane, such as FWHM, penumbra, peak value, symmetry and homogeneity. This system has been used to acquire a 3-dimension dosage distribution of dynamic wedge modulator and the transient process of beam dosage. The system configure and the tested beam profile images are also presented

Analysis of a Novel Diffractive Scanning-Wire Beam Position Monitor (BPM) for Discriminative Profiling of Electron Vs. X Ray Beams

International Nuclear Information System (INIS)

Tatchyn, R.

2011-01-01

Recent numerical studies of Free Electron Lasers (FELs) operating in the Self Amplified Spontaneous Emission (SASE) regime indicate a large sensitivity of the gain to the degree of transverse overlap (and associated phase coherence) between the electron and photon beams traveling down the insertion device. Simulations of actual systems imply that accurate detection and correction for this relative loss of overlap, rather than correction for the absolute departure of the electron beam from a fixed axis, is the preferred function of an FEL amplifier's Beam Position Monitor (BPM) and corrector systems. In this note we propose a novel diffractive BPM with the capability of simultaneously detecting and resolving the absolute (and relative) transverse positions and profiles of electron and x-ray beams co-propagating through an undulator. We derive the equations governing the performance of the BPM and examine its predicted performance for the SLAC Linac Coherent Light Source (LCLS), viz., for profiling multi-GeV electron bunches co-propagating with one-to-several-hundred keV x-ray beams. Selected research and development (r and d) tasks for fabricating and testing the proposed BPM are discussed.

Quantitative high dynamic range beam profiling for fluorescence microscopy

International Nuclear Information System (INIS)

Mitchell, T. J.; Saunter, C. D.; O’Nions, W.; Girkin, J. M.; Love, G. D.

2014-01-01

Modern developmental biology relies on optically sectioning fluorescence microscope techniques to produce non-destructive in vivo images of developing specimens at high resolution in three dimensions. As optimal performance of these techniques is reliant on the three-dimensional (3D) intensity profile of the illumination employed, the ability to directly record and analyze these profiles is of great use to the fluorescence microscopist or instrument builder. Though excitation beam profiles can be measured indirectly using a sample of fluorescent beads and recording the emission along the microscope detection path, we demonstrate an alternative approach where a miniature camera sensor is used directly within the illumination beam. Measurements taken using our approach are solely concerned with the illumination optics as the detection optics are not involved. We present a miniature beam profiling device and high dynamic range flux reconstruction algorithm that together are capable of accurately reproducing quantitative 3D flux maps over a large focal volume. Performance of this beam profiling system is verified within an optical test bench and demonstrated for fluorescence microscopy by profiling the low NA illumination beam of a single plane illumination microscope. The generality and success of this approach showcases a widely flexible beam amplitude diagnostic tool for use within the life sciences

IFMIF-LIPAc Beam Diagnostics. Profiling and Loss Monitoring Systems

International Nuclear Information System (INIS)

Egberts, J.

2012-01-01

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

Fast-scan, beam-profile monitor

International Nuclear Information System (INIS)

Waugh, A.F.

1977-01-01

A minimodular, data-acquisition system can be used to rapidly interrogate a 45-point matrix of beam-current sampling targets over the 3- x 12-in. rectangular, output beam cross section of a 50-A, neutral-beam ion source. This system, operating at a throughput rate of 12 μs per channel, can make several complete scans during the 10- to 25-ms-duration beam pulse. Data obtained are available in both analog and digital form. The analog signal is used to create an immediately interpretable CRT display of the beam-current density profile that shows how well the source is aimed. The digital data are held in buffer memory until transfer to a minicomputer for software processing and plotting

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

Energy Technology Data Exchange (ETDEWEB)

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.

On the use of magnetic buckets for ion beam profile tailoring

International Nuclear Information System (INIS)

MacGill, R. A.; Vizir, A.; Brown, I. G.

2000-01-01

Magnetic multipole plasma confinement geometries employing permanent magnet ''buckets'' are used extensively for a range of laboratory plasma applications. Among the several consequences for plasma confinement is the important result that the plasma can acquire a more-or-less flat density profile, which when embodied in an ion source, can also lead to a flat profile for the extracted ion beam. For many applications a uniform ion beam current density profile is quite advantageous, for example, for carrying out large-area ion implantation. There are, however, inherent limitations on the extent to which this approach to beam ''homogenization'' can be utilized, and even for a perfectly flat profile in the immediate postextraction region, the beam will evolve toward Gaussian as it propagates downstream. Here we describe the rare-earth permanent magnet bucket that we have incorporated into our broad-beam vacuum arc ion source, and its effect on the beam profile at the extractor and downstream. The experimental results are compared with a simple model for the beam profile evolution with axial distance. We find that the beam loses memory of its initially flat profile and relaxes to a more-or-less Gaussian shape in a relatively short axial distance ∼w/4θ, where w is the initial width of the flat beam profile and θ is the beamlet divergence half angle. (c) 2000 American Institute of Physics

Beam profile for Malaysian electron accelerator

International Nuclear Information System (INIS)

Abu Bakar Ghazali; Muhamad Zahidee Taat

2007-01-01

This paper comprises of two calculations that require in designing a dose profile for an electron accelerator machine before its fabrication. The first is to calculate the beam deflection due to changes of high voltage (HV) supply as well as the deflection coil currents so that the electron beam will only scan at the window foil of 18 cm length and 6 cm width. Secondly, we also require to calculate the beam profile at 50 mm underneath the window foil. The electron gun that produces a beam of 10 mm diameter has to be oscillated in a sawtooth wave for the prescribed window size at frequencies of 50 Hz and 400 Hz along the length and width directions respectively. For the beam deflection, we apply a basic formula from Lorentz force law to obtain a set of HV supply and the coil current that is suitable for both deflections and this result can assist in designing the coil current against HV changes via an electronic controller. The dose profile was calculated using the RMS current formulation along the length direction. We found that the measured and the calculated RMS currents are in comparable for the case of 1 MeV, 50 mA accelerator facility that is going to be installed at Nuclear Malaysia complex. A similar measurement will be carried out for our locally designed accelerator of 150 KeV, 10 mA after fabrication and installation of the machine are completed. (Author)

Ion beam profiling from the interaction with a freestanding 2D layer

Directory of Open Access Journals (Sweden)

Ivan Shorubalko

2017-03-01

Full Text Available Recent years have seen a great potential of the focused ion beam (FIB technology for the nanometer-scale patterning of a freestanding two-dimensional (2D layer. Experimentally determined sputtering yields of the perforation process can be quantitatively explained using the binary collision theory. The main peculiarity of the interaction between the ion beams and the suspended 2D material lies in the absence of collision cascades, featured by no interaction volume. Thus, the patterning resolution is directly set by the beam diameters. Here, we demonstrate pattern resolution beyond the beam size and precise profiling of the focused ion beams. We find out that FIB exposure time of individual pixels can influence the resultant pore diameter. In return, the pore dimension as a function of the exposure dose brings out the ion beam profiles. Using this method of determining an ion-beam point spread function, we verify a Gaussian profile of focused gallium ion beams. Graphene sputtering yield is extracted from the normalization of the measured Gaussian profiles, given a total beam current. Interestingly, profiling of unbeknown helium ion beams in this way results in asymmetry of the profile. Even triangular beam shapes are observed at certain helium FIB conditions, possibly attributable to the trimer nature of the beam source. Our method of profiling ion beams with 2D-layer perforation provides more information on ion beam profiles than the conventional sharp-edge scan method does.

The influence of lateral beam profile modifications in scanned proton and carbon ion therapy: a Monte Carlo study

CERN Document Server

Parodi, K; Kraemer, M; Sommerer, F; Naumann, J; Mairani, A; Brons, S

2010-01-01

Scanned ion beam delivery promises superior flexibility and accuracy for highly conformal tumour therapy in comparison to the usage of passive beam shaping systems. The attainable precision demands correct overlapping of the pencil-like beams which build up the entire dose distribution in the treatment field. In particular, improper dose application due to deviations of the lateral beam profiles from the nominal planning conditions must be prevented via appropriate beam monitoring in the beamline, prior to the entrance in the patient. To assess the necessary tolerance thresholds of the beam monitoring system at the Heidelberg Ion Beam Therapy Center, Germany, this study has investigated several worst-case scenarios for a sensitive treatment plan, namely scanned proton and carbon ion delivery to a small target volume at a shallow depth. Deviations from the nominal lateral beam profiles were simulated, which may occur because of misaligned elements or changes of the beam optic in the beamline. Data have been an...

A beam profile monitor for heavy ion beams at high impact energies

International Nuclear Information System (INIS)

Hausmann, A.; Stiebing, K.E.; Bethge, K.; Froehlich, O.; Koehler, E.; Mueller, A.; Rueschmann, G.

1994-01-01

A beam profile monitor for heavy ion beams has been developed for the use in experiments at the Heavy Ion Synchrotron SIS at Gesellschaft fuer Schwerionenforschung Darmstadt (GSI). Four thin scintillation fibres are mounted on one wheel and scan the ion beam sequentially in two linearly independent directions. They are read out via one single photomultiplier common to all four fibres into one time spectrum, which provides all information about beam position, beam extension, time structure and lateral homogeneity of the beam. The system operates in a wide dynamic range of beam intensities. ((orig.))

An Electron Beam Profile Instrument Based on FBGs

Directory of Open Access Journals (Sweden)

Dan Sporea

2014-08-01

Full Text Available Along with the dose rate and the total irradiation dose measurements, the knowledge of the beam localization and the beam profile/energy distribution in the beam are parameters of interest for charged particle accelerator installations when they are used in scientific investigations, industrial applications or medical treatments. The transverse profile of the beam, its position, its centroid location, and its focus or flatness depend on the instrument operating conditions or on the beam exit setup. Proof-of-concept of a new type of charged particle beam diagnostics based on fiber Bragg gratings (FBGs was demonstrated. Its operating principle relies on the measurement of the peak wavelength changes for an array of FBG sensors as function of the temperature following the exposure to an electron beam. Periodically, the sensor irradiation is stopped and the FBG are force cooled to a reference temperature with which the temperature influencing each sensor during beam exposure is compared. Commercially available FBGs, and FBGs written in radiation resistant optical fibers, were tested under electron beam irradiation in order to study their possible use in this application.

Beam-profile monitor using a sodium-vapour

CERN Multimedia

1972-01-01

Beam-profile monitor using a sodium-vapour curtain at 45 degrees to the ISR beam in Ring I (sodium generator is in white cylinder just left of centre). Electrons produced by ionization of the sodium vapour give an image of the beam on a fluorescent screen that is observed by a TV camera (at upper right).

K-band EPR dosimetry: small-field beam profile determination with miniature alanine dosimeter

International Nuclear Information System (INIS)

Chen, Felipe; Graeff, Carlos F.O.; Baffa, Oswaldo

2005-01-01

The use of small-size alanine dosimeters presents a challenge because the signal intensity is less than the spectrometer sensitivity. K-band (24 GHz) EPR spectrometer seems to be a good compromise between size and sensitivity of the sample. Miniature alanine pellets were evaluated for small-field radiation dosimetry. Dosimeters of DL-alanine/PVC with dimensions of 1.5 mm diameter and 2.5 mm length with 5 mg mass were developed. These dosimeters were irradiated with 10 MV X-rays in the dose range 0.05-60 Gy and the first harmonic (1 h) spectra were recorded. Microwave power, frequency and amplitude of modulation were optimized to obtain the best signal-to-noise ratio (S/N). For beam profile determination, a group of 25 dosimeters were placed in an acrylic device with dimensions of (7.5x2.5x1) cm 3 and irradiated with a (3x3) cm 2 10 MV X-rays beam field size. The dose at the central region of the beam was 20 Gy at a depth of 2.2 cm (build up for acrylic). The acrylic device was oriented perpendicular to the beam axis and to the gantry rotation axis. For the purposes of comparison of the spatial resolution, the beam profile was also determined with a radiographic film and 2 mm aperture optical densitometer; in this case the dose was 1 cGy. The results showed a similar spatial resolution for both types of dosimeters. The dispersion in dose reading was larger for alanine in comparison with the film, but alanine dosimeters can be read faster and more directly than film over a wide dose range

An online, energy-resolving beam profile detector for laser-driven proton beams

Energy Technology Data Exchange (ETDEWEB)

Metzkes, J.; Rehwald, M.; Obst, L.; Schramm, U. [Helmholtz-Zentrum Dresden–Rossendorf (HZDR), Bautzner Landstr. 400, 01328 Dresden (Germany); Technische Universität Dresden, 01062 Dresden (Germany); Zeil, K.; Kraft, S. D.; Sobiella, M.; Schlenvoigt, H.-P. [Helmholtz-Zentrum Dresden–Rossendorf (HZDR), Bautzner Landstr. 400, 01328 Dresden (Germany); Karsch, L. [OncoRay-National Center for Radiation Research in Oncology, Technische Universität Dresden, 01307 Dresden (Germany)

2016-08-15

In this paper, a scintillator-based online beam profile detector for the characterization of laser-driven proton beams is presented. Using a pixelated matrix with varying absorber thicknesses, the proton beam is spatially resolved in two dimensions and simultaneously energy-resolved. A thin plastic scintillator placed behind the absorber and read out by a CCD camera is used as the active detector material. The spatial detector resolution reaches down to ∼4 mm and the detector can resolve proton beam profiles for up to 9 proton threshold energies. With these detector design parameters, the spatial characteristics of the proton distribution and its cut-off energy can be analyzed online and on-shot under vacuum conditions. The paper discusses the detector design, its characterization and calibration at a conventional proton source, as well as the first detector application at a laser-driven proton source.

Monitor of SC beam profiles

CERN Document Server

CERN PhotoLab

1977-01-01

A high-resolution secondary emission grid for the measurement of SC beam profiles. Modern techniques of metal-ceramic bonding, developed for micro-electronics, have been used in its construction. (See Annual Report 1977 p. 105 Fig. 12.)

Estimation and display of beam density profiles

Energy Technology Data Exchange (ETDEWEB)

Dasgupta, S; Mukhopadhyay, T; Roy, A; Mallik, C

1989-03-15

A setup in which wire-scanner-type beam-profile monitor data are collected on-line in a nuclear data-acquisition system has been used and a simple algorithm for estimation and display of the current density distribution in a particle beam is described.

The Beam Profile Monitoring System for the CERN IRRAD Proton Facility

CERN Document Server

Ravotti, F; Glaser, M; Matli, E; Pezzullo, G; Gan, K K; Kagan, H; Smith, S; Warner, J D

2017-01-01

GeV/c proton beam is used. During beam steering and irradiation, the intensity and the transverse profile of the proton beam are monitored online with custom-made Beam Profile Monitor (BPM) devices. In this work, we present the design and the architecture of the IRRAD BPM system, some results on its performance with the proton beam, as well as its planned grades.

Beam envelope profile of non-centrosymmetric polygonal phase space

International Nuclear Information System (INIS)

Chen Yinbao; Xie Xi

1984-01-01

The general theory of beam envelope profile of non-centrosymmetric polygonal phase space is developed. By means of this theory the beam envelope profile of non-centrosymmetric polygonal phase space can be calculated directly. An example is carried out in detail to show the practical application of the theory

Beam position monitor sensitivity for low-β beams

International Nuclear Information System (INIS)

Shafer, R.E.

1993-01-01

At low velocities, the EM field of a particle in a conducting beam tube is no longer a TEM wave, but has a finite longitudinal extent. The net effect of this is to reduce the coupling of the high-frequency Fourier components of the beam current to BPM (beam position monitor) electrodes, which modifies the BPM sensitivity to beam displacement. This effect is especially pronounced for high-frequency, large-aperture pickups used for low-β beams. Non-interceptive beam position monitors used in conjunction with high frequency RFQ (radio-frequency-quadrupole) and DTL (drift-tube-linac) accelerators fall into this category. When testing a BPM with a thin wire excited with either pulses or high-frequency sinusoidal currents, the EM wave represents the principal (TEM) mode in a coaxial transmission line, which is equivalent to a highly relativistic (β = 1) beam. Thus wire measurements are not suitable for simulating slow particle beams in high bandwidth diagnostic devices that couple to the image currents in the beam tube wall. Attempts to load the tin wire either capacitively or inductively to slow the EM wave down have met with limited success. In general, the equations used to represent the 2-D response of cylindrical-geometry BPMs to charged-particle beams make several assumptions: (1) the BPM electrodes are flush with and grounded to the surface of the conducting beam tube; (2) the beam is a line source (pencil beam); (3) the longitudinal extent of the EM field of a beam particle at the beam tube wall is zero, corresponding to a highly relativistic beam. The purpose of this paper is to make some quantitative estimates of the corrections to the conventional approximations when a BPM is used to measure the position of low velocity (low-β) beams

High intensity beam profile monitors for the LAMPF primary beam lines

International Nuclear Information System (INIS)

Hoffman, E.W.; Macek, R.J.; van Dyck, O.; Lee, D.; Harvey, A.; Bridge, J.; Cainet, J.

1979-01-01

Two types of beam profile monitors are in use at LAMPF to measure the properties of the 800 MeV, 500 μA proton beam external to the linac. Both types use secondary electron emission from a wire to produce a current signal proportional to the amount of proton beam that intercepts the wire. The wire scanner system uses a pair of orthogonal wires which are passed through the beam and the harp system uses two fixed planes of parallel wires. Most of the harps are not retractable and are exposed continuously to the primary beam. The high beam intensities available lead to a number of technical problems for instruments that intercept the beam or are close to primary beam targets. The thermal, electrical, radiation-damage, and material selection problems encountered, and some solutions which have been implemented are discussed

Non-destructive beam profile monitor at HIMAC

International Nuclear Information System (INIS)

Sato, S.; Araki, N.; Hosaka, M.

1995-01-01

Non-destructive profile monitors (NDPM), based on micro-channel plate (MCP), have been developed and installed in both the synchrotron ring and high-energy beam transport (HEBT) line at HIMAC. Beam test using these monitors have been carried out since April of 1995 to investigate a change of vertical beam size in synchrotron and a possibility of observing beam with high energy by one pass. In this paper the measurement system is mainly reported, and the preliminary results are also briefly presented. (author)

Beam profile measurement with flying wires at the Fermilab Recycler Ring

Energy Technology Data Exchange (ETDEWEB)

Carcagno, R.; Pishchalnikov, Yu.; Krider, J.; Hu, M.; Lorman, E.; Marchionni, A.; Pordes, S.; Wilson, P.; Zagel, J.; /Fermilab

2005-05-01

Flying wires were installed at the Fermilab Recycler Ring for transverse beam profile measurement for both proton and antiproton beams. The following note describes the system configuration, calibration and resolution of the flying wire system, interactions between the wires and the beam, as well as analysis of the transverse beam profile in the presence of a stochastic cooling system.

Beam profile measurement with flying wires at the Fermilab Recycler Ring

International Nuclear Information System (INIS)

Carcagno, R.; Pishchalnikov, Yu.; Krider, J.; Hu, M.; Lorman, E.; Marchionni, A.; Pordes, S.; Wilson, P.; Zagel, J.

2005-01-01

Flying wires were installed at the Fermilab Recycler Ring for transverse beam profile measurement for both proton and antiproton beams. The following note describes the system configuration, calibration and resolution of the flying wire system, interactions between the wires and the beam, as well as analysis of the transverse beam profile in the presence of a stochastic cooling system

A multi-wire beam profile monitor in the AGS

Energy Technology Data Exchange (ETDEWEB)

Huang, H.; Buxton, W.; Castillo, V.; Glenn, J.W. [and others

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.

Ionization beam profile monitor for operation under hard environmental conditions

International Nuclear Information System (INIS)

Teterev, Yu.G.; Kaminski, G.; Phi Thanh Huong; Kaminski, G.; Kozik, E.

2010-01-01

The design and the performance of the Ionization Beam Profile Monitor (IBPM) operating on the residual gas ionization principle are described. The main advantage of the constructed device is the non-contact measuring method. Operating under hard environmental conditions it delivers the information about the primary beam position, profile and intensity in 'on-line' regime. It was found out that the device is capable to operate in vacuum in the range of 10 -6 /10 -3 mbar without the loss of the resolution power at the beam current as low as a few nA. The IBPM is prospective for beam profile monitoring due to long time. Emergency situations do not lead to decrease of its operability.

Computed tomographic reconstruction of beam profiles with a multi-wire chamber

International Nuclear Information System (INIS)

Alonso, J.R.; Tobias, C.A.; Chu, W.T.

1979-03-01

MEDUSA (MEdical Dose Uniformity SAmpler), a 16 plane multi-wire proportional chamber, has been built to accurately measure beam profiles. The large number of planes allows for reconstruction of highly detailed beam intensity structures by means of Fourier convolution reconstruction techniques. This instrument is being used for verification and tuning of the Bevalac radiotherapy beams, but has potential applications in many beam profile monitoring situations

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

Energy Technology Data Exchange (ETDEWEB)

Hendriks, C.; Uittenbosch, T.; Cameron, D.; Kellogg, S.; Gray, D.; Buckley, K.; Schaffer, P.; Verzilov, V.; Hoehr, C. [TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3 (Canada)

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.

Excimer laser beam profile recording based on electrochemical etched polycarbonate

International Nuclear Information System (INIS)

Parvin, P.; Jaleh, B.; Zangeneh, H.R.; Zamanipour, Z.; Davoud-Abadi, Gh.R.

2008-01-01

There is no polymeric detector used to register the beam profile of UV lasers. Here, a method is proposed for the measurement of intensive UV beam pattern of the excimer lasers based on the photoablated polycarbonate detector after coherent UV exposure and the subsequent electrochemical etching. UV laser induced defects in the form of self-microstructuring on polycarbonate are developed to replicate the spatial intensity distribution as a beam profiler

Excimer laser beam profile recording based on electrochemical etched polycarbonate

Energy Technology Data Exchange (ETDEWEB)

Parvin, P. [Physics Department, Amirkabir University of Technology, P.O. Box 15875-4413, Hafez Ave, Tehran (Iran, Islamic Republic of); Laser Research Center, AEOI, P.O. Box 1165-8486, Tehran (Iran, Islamic Republic of)], E-mail: parvin@aut.ac.ir; Jaleh, B. [Physics Department, Bu-Ali Sina University, Postal Code 65174, Hamedan (Iran, Islamic Republic of); Zangeneh, H.R. [Physics Department, Amirkabir University of Technology, P.O. Box 15875-4413, Hafez Ave, Tehran (Iran, Islamic Republic of); Zamanipour, Z. [Laser Research Center, AEOI, P.O. Box 1165-8486, Tehran (Iran, Islamic Republic of); Davoud-Abadi, Gh.R. [Physics Department, Amirkabir University of Technology, P.O. Box 15875-4413, Hafez Ave, Tehran (Iran, Islamic Republic of)

2008-08-15

There is no polymeric detector used to register the beam profile of UV lasers. Here, a method is proposed for the measurement of intensive UV beam pattern of the excimer lasers based on the photoablated polycarbonate detector after coherent UV exposure and the subsequent electrochemical etching. UV laser induced defects in the form of self-microstructuring on polycarbonate are developed to replicate the spatial intensity distribution as a beam profiler.

Wire Scanner Beam Profile Measurements for the LANSCE Facility

International Nuclear Information System (INIS)

Gilpatrick, John D.; Gruchalla, Michael E.; Martinez, Derwin; Pillai, Chandra; Rodriguez Esparza, Sergio; Sedillo, James Daniel; Smith, Brian G.

2012-01-01

The Los Alamos Neutron Science Center (LANSCE) is replacing beam profile measurement systems, commonly known as Wire Scanners (WS). Using the principal of secondary electron emission, the WS measurement system moves a wire or fiber across an impinging particle beam, sampling a projected transverse-beam distribution. Because existing WS actuators and electronic components are either no longer manufactured or home-built with antiquated parts, a new WS beam profile measurement is being designed, fabricated, and tested. The goals for these new WS's include using off-the-shelf components while eliminating antiquated components, providing quick operation while allowing for easy maintainability, and tolerating external radioactivation. The WS measurement system consists of beam line actuators, a cable plant, an electronics processor chassis, and software located both in the electronics chassis (National Instruments LabVIEW) and in the Central Control Room (EPICS-based client software). This WS measurement system will measure Hand H + LANSCE-facility beams and will also measure less common beams. This paper describes these WS measurement systems.

Employing Beam-Gas Interaction Vertices for Transverse Profile Measurements

CERN Document Server

Rihl, Mariana; Baglin, Vincent; Barschel, Colin; Bay, Aurelio; Blanc, Frederic; Bravin, Enrico; Bregliozzi, Giuseppe; Chritin, Nicolas; Dehning, Bernd; Ferro-Luzzi, Massimiliano; Gaspar, Clara; Gianì, Sebastiana; Giovannozzi, Massimo; Greim, Roman; Haefeli, Guido; Hopchev, Plamen; Jacobsson, Richard; Jensen, Lars; Jones, Owain Rhodri; Jurado, Nicolas; Kain, Verena; Karpinski, Waclaw; Kirn, Thomas; Kuhn, Maria; Luthi, Berengere; Magagnin, Paolo; Matev, Rosen; Nakada, Tatsuya; Neufeld, Niko; Panman, Jaap; Rakotomiaramanana, Barinjaka; Salustino Guimaraes, Valdir; Salvant, Benoit; Schael, Stefan; Schneider, Olivier; Schwering, Georg; Tobin, Mark; Veness, Raymond; Veyrat, Quentin; Vlachos, Sotiris; Wlochal, Michael; Xu, Zhirui; von Dratzig, Arndt

2016-01-01

Interactions of high-energy beam particles with residual gas offer a unique opportunity to measure the beam profile in a non-intrusive fashion. Such a method was successfully pioneered* at the LHCb experiment using a silicon microstrip vertex detector. During the recent Large Hadron Collider shutdown at CERN, a demonstrator Beam-Gas Vertexing system based on eight scintillating-fibre modules was designed**, constructed and installed on Ring 2 to be operated as a pure beam diagnostics device. The detector signals are read out and collected with LHCb-type front-end electronics and a DAQ system consisting of a CPU farm. Tracks and vertices will be reconstructed to obtain a beam profile in real time. Here, first commissioning results are reported. The advantages and potential for future applications of this technique are discussed.

An Electron-Beam Profile Monitor Using Fresnel Zone Plates

International Nuclear Information System (INIS)

Nakamura, Norio; Sakai, Hiroshi; Iida, Kensuke; Shinoe, Kenji; Takaki, Hiroyuki; Fujisawa, Masami; Hayano, Hitoshi; Muto, Toshiya; Nomura, Masaharu; Kamiya, Yukihide; Koseki, Tadashi; Amemiya, Yoshiyuki; Aoki, Nobutada; Nakayama, Koichi

2004-01-01

We have developed a beam profile monitor using two Fresnel zone plates (FZPs) at the KEK-ATF (Accelerator Test Facility) damping ring to measure small electron-beam sizes for low-emittance synchrotron radiation sources. The monitor has a structure of an X-ray microscope, where two FZPs constitute an X-ray imaging optics. In the monitor system, the synchrotron radiation from the electron beam at the bending magnet is monochromatized to 3.235-keV X-rays by a crystal monochromator and the transverse electron-beam image is twenty-times magnified by the two FZPs and detected on an X-ray CCD camera. This monitor has the following advantages: (1) high spatial resolution, (2) non-destructive measurement, (3) real-time monitoring, and (4) direct electron-beam imaging. With the beam profile monitor, we have succeeded in obtaining a clear electron-beam image and measuring the extremely small beam size less than 10 μm. The measured magnification of the imaging optics was in good agreement with the design value

The characterization of beam profile by modification of electrode shape

International Nuclear Information System (INIS)

Lee, Chan Young; Lee, Jae Sang

2010-01-01

Ion sources have been used for variety of industrial application over the past few decades and our research group has been studied about high current and large dimension ion source to meet the requirement from beam user. For a mass production in industry, a wide beam divergence and a beam profile of a broadly Gaussian shape is very needed. Generally, the production process like roll-to-roll or in-line system is need one-meter in diameter, ±5% in uniformity. Therefore it is difficult to apply with present system like 0.3-meter in diameter, ±20% in uniformity and needed new type ion source. In this study, it is approached with modification of electrode grid shape without fabrication of new type ion source. We modified from parallel type to hemispherical type electrode grid to secure large dimension ion beam and were discussed with respect to beam profile calculated with IGUN code simulation. Also, we identified beam profile before and after modification of electrode grid system(cathode, Acelldecel grid) with measurement of faraday cup

Measurement of an electron-beam size with a beam profile monitor using Fresnel zone plates

International Nuclear Information System (INIS)

Iida, K.; Nakamura, N.; Sakai, H.; Shinoe, K.; Takaki, H.; Fujisawa, M.; Hayano, H.; Nomura, M.; Kamiya, Y.; Koseki, T.; Amemiya, Y.; Aoki, N.; Nakayama, K.

2003-01-01

We present a non-destructive and real-time beam profile monitor using Fresnel zone plates (FZPs) and the measurement of an electron-beam size with this monitor in the KEK-Accelerator Test Facility (ATF) damping ring. The monitor system has the structure of a long-distance X-ray microscope, where two FZPs constitute an X-ray imaging optics. The synchrotron radiation from the electron beam at the bending magnet is monochromatized by a crystal monochromator and the transverse electron beam image is twenty times magnified by the two FZPs and detected on an X-ray CCD camera. The expected spatial resolution for the selected photon energy of 3.235 keV is sufficiently high to measure the horizontal and vertical beam sizes of the ATF damping ring. With the beam profile monitor, we succeeded in obtaining a clear electron-beam image and measuring the extremely small beam size less than 10 μm. The measured magnification of the X-ray imaging optics in the monitor system was in good agreement with the design value

The generation of absorbed dose profiles of proton beam in water using Geant4 code

International Nuclear Information System (INIS)

Christovao, Marilia T.; Campos, Tarcisio Passos R. de

2007-01-01

The present article approaches simulations on the proton beam radiation therapy, using an application based on the code GEANT4, with Open GL as a visualization drive and JAS3 (Java Analysis Studio) analysis data tools systems, implementing the AIDA interfaces. The proton radiotherapy is adapted to treat cancer or other benign tumors that are close to sensitive structures, since it allows precise irradiation of the target with high doses, while the health tissues adjacent to vital organs and tissues are preserved, due to physical property of dose profile. GEANT4 is a toolkit for simulating the transport of particles through matter, in complex geometries. Taking advantage of the object-oriented project features, the user can adapt or extend the tool in all domain, due to the flexibility of the code, providing a subroutine's group for materials definition, geometries and particles properties in agreement with the user's needs to generate the Monte Carlo simulation. In this paper, the parameters of beam line used in the simulation possess adjustment elements, such as: the range shifter, composition and dimension; the beam line, energy, intensity, length, according with physic processes applied. The simulation result is the depth dose profiles on water, dependent on the various incident beam energy. Starting from those profiles, one can define appropriate conditions for proton radiotherapy in ocular region. (author)

Wire Scanner Beam Profile Measurements for the LANSCE Facility

Energy Technology Data Exchange (ETDEWEB)

Gilpatrick, John D. [Los Alamos National Laboratory; Gruchalla, Michael E. [Los Alamos National Laboratory; Martinez, Derwin [Los Alamos National Laboratory; Pillai, Chandra [Los Alamos National Laboratory; Rodriguez Esparza, Sergio [Los Alamos National Laboratory; Sedillo, James Daniel [Los Alamos National Laboratory; Smith, Brian G. [Los Alamos National Laboratory

2012-05-15

The Los Alamos Neutron Science Center (LANSCE) is replacing beam profile measurement systems, commonly known as Wire Scanners (WS). Using the principal of secondary electron emission, the WS measurement system moves a wire or fiber across an impinging particle beam, sampling a projected transverse-beam distribution. Because existing WS actuators and electronic components are either no longer manufactured or home-built with antiquated parts, a new WS beam profile measurement is being designed, fabricated, and tested. The goals for these new WS's include using off-the-shelf components while eliminating antiquated components, providing quick operation while allowing for easy maintainability, and tolerating external radioactivation. The WS measurement system consists of beam line actuators, a cable plant, an electronics processor chassis, and software located both in the electronics chassis (National Instruments LabVIEW) and in the Central Control Room (EPICS-based client software). This WS measurement system will measure Hand H{sup +} LANSCE-facility beams and will also measure less common beams. This paper describes these WS measurement systems.

A neutral-beam profile monitor with a phosphor screen and a high-sensitivity camera for the J-PARC KOTO experiment

Science.gov (United States)

Matsumura, T.; Kamiji, I.; Nakagiri, K.; Nanjo, H.; Nomura, T.; Sasao, N.; Shinkawa, T.; Shiomi, K.

2018-03-01

We have developed a beam-profile monitor (BPM) system to align the collimators for the neutral beam-line at the Hadron Experimental Facility of J-PARC. The system is composed of a phosphor screen and a CCD camera coupled to an image intensifier mounted on a remote control X- Y stage. The design and detailed performance studies of the BPM are presented. The monitor has a spatial resolution of better than 0.6 mm and a deviation from linearity of less than 1%. These results indicate that the BPM system meets the requirements to define collimator-edge positions for the beam-line tuning. Confirmation using the neutral beam for the KOTO experiment is also presented.

Focused ion-beam line profiles: A study of some factors affecting beam broadening

International Nuclear Information System (INIS)

Templeton, I.M.; Champion, H.G.

1995-01-01

The current--density profile of a focused ion beam (FIB) has a central peak accompanied by broader ''wings'' that, while unimportant in lithographic applications, can lead to unwanted effects during an implantation operation. The origin of the wings, and hence the best way to minimize them, is not clear and needs further study. We have measured the line profiles of several of the ions available in our FIB machine as a function of a number of variables, under ultrahigh vacuum (UHV) conditions. No effects are observed from changes in emission current or deliberate defocusing of the objective lens. There are some changes with beam aperture and/or current, but the biggest differences seem to be associated with a change of source type and hence, possibly, with a change in the source/extractor configuration or in the alloy and the emission process. The wing amplitudes are appreciably lower than many previously observed, and their profiles, at least for the lighter ions studied (Be ++ , Be + , and B + ), are Gaussian rather than exponential. It seems possible that our UHV conditions may have eliminated a scattering mechanism responsible for the larger, exponential wings previously observed. The corresponding beam and rectangle-edge profiles have been calculated. copyright 1995 American Vacuum Society

Flatness of two-dimensional beam profile measured with an ionization chamber array

International Nuclear Information System (INIS)

Stefanovski, Z.

2006-01-01

Open beam profiles are basic dosimetric characteristics for the formation of the dose calculation algorithms parameters and for determination of beam quality. One characteristic of the beam profiles as a measure for the beam quality is the field flatness defined as ratio of the difference of maximum and minimum dose in central 80% of the field to the sum of these doses in the part of the field. The measurements, instead with an ordinary ionization chamber, were performed with a chamber array in two depths (1.6 cm and 10 cm) in water phantom. Nominal photon beam energy was 6 MV and field size was 25 cm x 25 cm on the water surface. Field flatness was in the range of 1-2 % which is in accordance with the data acquired during the acceptance testing and commissioning of the accelerators. with the array chamber the beam profiles can be performed quickly and preciously. These features recommend a chamber array as an excellent tool for periodic quality control of beam profiles. (Author)

Random source generating far field with elliptical flat-topped beam profile

International Nuclear Information System (INIS)

Zhang, Yongtao; Cai, Yangjian

2014-01-01

Circular and rectangular multi-Gaussian Schell-model (MGSM) sources which generate far fields with circular and rectangular flat-topped beam profiles were introduced just recently (Sahin and Korotkova 2012 Opt. Lett. 37 2970; Korotkova 2014 Opt. Lett. 39 64). In this paper, a random source named an elliptical MGSM source is introduced. An analytical expression for the propagation factor of an elliptical MGSM beam is derived. Furthermore, an analytical propagation formula for an elliptical MGSM beam passing through a stigmatic ABCD optical system is derived, and its propagation properties in free space are studied. It is interesting to find that an elliptical MGSM source generates a far field with an elliptical flat-topped beam profile, being qualitatively different from that of circular and rectangular MGSM sources. The ellipticity and the flatness of the elliptical flat-topped beam profile in the far field are determined by the initial coherence widths and the beam index, respectively. (paper)

A high resolution, single bunch, beam profile monitor

International Nuclear Information System (INIS)

Norem, J.

1992-01-01

We developed a beam monitoring system which could be used to measure beam profile, size and stability at the final forms of a beamline or collider. The system uses nonimaging bremsstrahlung optics. The immediate use for this system would be examining the final focus spot at the SLAC/FFTR

Analysis of the Influence of Fibre Diameter on Wirescanner Beam Profile Measurements

CERN Document Server

King, Quentin

1988-01-01

It is often important to be able to measure beam profiles in regions where the beam size is very small. Following concern that the profile measurement might be affected by having a beam size of the same order as the diameter of the wirescanner fibre, the effect was analysed numerically, and the results are presented.

Ultra-shallow arsenic implant depth profiling using low-energy nitrogen beams

International Nuclear Information System (INIS)

Fearn, Sarah; Chater, Richard; McPhail, David

2004-01-01

Sputtering of silicon by low-energy nitrogen primary ion beams has been studied by a number of authors to characterize the altered layer, ripple formation and the sputtered yields of secondary ions [Surf. Sci. 424 (1999) 299; Appl. Phys. A: Mater. Sci. Process 53 (1991) 179; Appl. Phys. Lett. 73 (1998) 1287]. This study examines the application of low-energy nitrogen primary ion beams for the possible depth profiling of ultra-shallow arsenic implants into silicon. The emphasis of this work is on the matrix silicon signals in the pre-equilibrium surface region that are used for dose calibration. Problems with these aspects of the concentration depth profiling can give significant inconsistencies well outside the error limits of the quoted dose for the arsenic implantation as independently verified by CV profiling. This occurs during depth profiling with either oxygen primary ion beams (with and without oxygen leaks) or cesium primary ion beams

Non-destructive profile measurement of intensive heavy ion beams; Zerstoerungsfreie Profilmessung intensiver Schwerionenstrahlen

Energy Technology Data Exchange (ETDEWEB)

Becker, Frank

2010-02-08

Within the framework of the FAIR-project (Facility for Antiproton and Ion Research) at GSI (Helmholtz Center for Heavy Ion Research), high intensity beams from protons to uranium ions with kinetic energies up to 30 AGeV are foreseen. Present GSI-accelerators like the UNILAC and the Heavy Ion Synchrotron (SIS-18) with a magnetic rigidity of 18 Tm will be used as injectors for the future synchrotron (SIS-100). Their beam current will be increased by up to two orders of magnitude. An accurate beam position and beam profile measurement is mandatory for a safe operation of transport sections, in particular in front of production targets (Fragment Separator (FRS)-target, anti p-production-target and Warm Dense Matter (WDM)-targets). Conventional intercepting profile monitors will not withstand the thermal stress of intensive ion beams, particularly for low energy applications or focused beams. For transverse profile determination a non-intercepting Beam Induced Fluorescence (BIF)-monitor was developed, working with residual gas. The BIF-monitor exploits fluorescence light emitted by residual gas molecules after atomic collisions with beam ions. Fluorescence-images were recorded with an image-intensified camera system, and beam profiles were obtained by projecting these images. Within the scope of this dissertation the following topics have been investigated: The photon yield, profile shape and background contribution were determined for different ion species (H{sup +}, S{sup 6+}, Ar{sup 18+}, K{sup +}, Ni{sup 9+}, Xe{sup 48+}, Ta{sup 24+}, Au{sup 65+}, U{sup 73+}), beam energies (7.7 AkeV-750 AMeV), gas pressures (10{sup -6}-3 mbar) and gas species (N{sub 2}, He, Ne, Ar, Kr, Xe). Applying an imaging spectrograph and narrowband 10 nm interference filters, the spectral response was mapped and associated with the corresponding gas transitions. Spectrally resolved beam profiles were also obtained form the spectrographic images. Major results are the light yield showing a

Fen+ beam profile diagnostics based on Al2O3: Cr scintillating screen

International Nuclear Information System (INIS)

He Tie; Lei Jiarong; Liu Meng; An Li; Wang Xinhua; Zheng Pu

2013-01-01

Some techniques of beam profile measurements such as wire rotating scan, Faraday cups array and infrared imaging were investigated. A measurement device was built based on scintillating screen to cater for the demand of accelerator beam profile diagnostics. The device was bombarded under several tens to hundred nanoampere Fe n+ (n=5-12) ion beam. The Fe n+ ion beam experiment shows that the imaging saturation is mainly caused by light intensity rather than scintillating screen. A way to solve the saturation problem with a specially developed lens was mentioned. The grayscale of beam profile imaging is approximately linear with respect to the beam intensity, and the reason for formation of this relationship was analyzed. (authors)

Emittance compensation with dynamically optimized photoelectron beam profiles

Energy Technology Data Exchange (ETDEWEB)

Rosenzweig, J.B. [Department of Physics and Astronomy, UCLA, 405 Hilgard Avenue, Los Angeles, CA 90095 (United States)]. E-mail: rosen@physics.ucla.edu; Cook, A.M. [Department of Physics and Astronomy, UCLA, 405 Hilgard Avenue, Los Angeles, CA 90095 (United States); England, R.J. [Department of Physics and Astronomy, UCLA, 405 Hilgard Avenue, Los Angeles, CA 90095 (United States); Dunning, M. [Department of Physics and Astronomy, UCLA, 405 Hilgard Avenue, Los Angeles, CA 90095 (United States); Anderson, S.G. [Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, CA 94550 (United States); Ferrario, Massimo [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionale di Frascati, Via E. Fermi 41, Frascati, Rome (Italy)

2006-02-01

Much of the theory and experimentation concerning creation of a high-brightness electron beam from a photocathode, and then applying emittance compensation techniques, assumes that one must strive for a uniform density electron beam, having a cylindrical shape. On the other hand, this shape has large nonlinearities in the space-charge field profiles near the beam's longitudinal extrema. These nonlinearities are known to produce both transverse and longitudinal emittance growth. On the other hand, it has recently been shown by Luiten that by illuminating the cathode with an ultra-short laser pulse of appropriate transverse profile, a uniform density, ellipsoidally shaped bunch is dynamically formed, which then has linear space-charge fields in all dimensions inside of the bunch. We study here this process, and its marriage to the standard emittance compensation scenario that is implemented in most recent photoinjectors. It is seen that the two processes are compatible, with simulations indicating a very high brightness beam can be obtained. The robustness of this scheme to systematic errors is examined. Prospects for experimental tests of this scheme are discussed.

Emittance compensation with dynamically optimized photoelectron beam profiles

International Nuclear Information System (INIS)

Rosenzweig, J.B.; Cook, A.M.; England, R.J.; Dunning, M.; Anderson, S.G.; Ferrario, Massimo

2006-01-01

Much of the theory and experimentation concerning creation of a high-brightness electron beam from a photocathode, and then applying emittance compensation techniques, assumes that one must strive for a uniform density electron beam, having a cylindrical shape. On the other hand, this shape has large nonlinearities in the space-charge field profiles near the beam's longitudinal extrema. These nonlinearities are known to produce both transverse and longitudinal emittance growth. On the other hand, it has recently been shown by Luiten that by illuminating the cathode with an ultra-short laser pulse of appropriate transverse profile, a uniform density, ellipsoidally shaped bunch is dynamically formed, which then has linear space-charge fields in all dimensions inside of the bunch. We study here this process, and its marriage to the standard emittance compensation scenario that is implemented in most recent photoinjectors. It is seen that the two processes are compatible, with simulations indicating a very high brightness beam can be obtained. The robustness of this scheme to systematic errors is examined. Prospects for experimental tests of this scheme are discussed

Two-photon equivalent weighting of spatial excimer laser beam profiles

Science.gov (United States)

Eva, Eric; Bauer, Harry H.; Metzger, K.; Pfeiffer, A.

2001-04-01

Damage in optical materials for semiconductor lithography applications caused by exposure to 248 or 193 nm light is usually two-photon driven, hence it is a nonlinear function of incident intensity. Materials should be tested with flat- topped temporal and spatial laser beam profiles to facilitate interpretation of data, but in reality this is hard to achieve. Sandstrom provided a formula that approximates any given temporal pulse shape with a two- photon equivalent rectangular pulse (Second Symposium on 193 nm Lithography, Colorado Springs 1997). Known as the integral-square pulse duration, this definition has been embraced as an industry standard. Originally faced with the problem of comparing results obtained with pseudo-Gaussian spatial profiles to literature data, we found that a general solution for arbitrarily inhomogeneous spatial beam profiles exists which results in a definition much similar to Sandstrom's. In addition, we proved the validity of our approach in experiments with intentionally altered beam profiles.

Preliminary results of spatially resolved ECR ion beam profile investigations

International Nuclear Information System (INIS)

Panitzsch, L.; Stalder, M.; Wimmer-Schweingruber, R.F.

2012-01-01

The profile of an ion beam produced in an Electron Cyclotron Resonance Ion Source (ECRIS) can vary greatly depending on the source settings and the ion-optical tuning. Strongly focussed ion beams form circular structures (hollow beams) as predicted by simulations and observed in experiments. Each of the rings is predicted to be dominated by ions with same or at least similar m/q-ratios due to ion-optical effects. To check this we performed a series of preliminary investigations to test the required tuning capabilities of our ion source. This includes beam focussing (A) and beam steering (B) using a 3D-movable extraction. Having tuned the source to deliver a beam of strongly focussed ions of different ion species and having steered this beam to match the transmittance area of the sector magnet we also recorded the ion charge state distribution of the strongly focussed beam profile at different, spatially limited positions (C). The preliminary results will be introduced within this paper: it appears that our 3D-movable extraction is very efficient to steer and to focus the beam strongly. The paper is followed by the slides of the presentation. (authors)

Measurement of electron beams profile of pierce type electron source using sensor of used Tv tube

International Nuclear Information System (INIS)

Darsono; Suhartono; Suprapto; Elin Nuraini

2015-01-01

The measurement of an electron beam profile has been performed using electron beam monitor based on method of phosphorescent materials. The main components of the electron beam monitor consists of a fluorescent sensor using a used Tv tube, CCTV camera to record images on a Tv screen, video adapter as interface between CCTV and laptop, and the laptop as a viewer and data processing. Two Pierce-type electron sources diode and triode was measured the shape of electron beam profile in real time. Results of the experiments showed that the triode electron source of Pierce type gave the shape of electron beam profiles better than that of the diode electron source .The anode voltage is not so influential on the beam profile shape. The focused voltage in the triode electron source is so influence to the shape of the electron beam profile, but above 5 kV no great effect. It can be concluded that the electron beam monitor can provide real time observations and drawings shape of the electron beam profile displayed on the used Tv tube glass screen which is the real picture of the shape of the electron beam profile. Triode electron source produces a better electron beam profile than that of the diode electron source. (author)

R & D of a Gas-Filled RF Beam Profile Monitor for Intense Neutrino Beam Experiments

Energy Technology Data Exchange (ETDEWEB)

Yonehara, K. [Fermilab; Backfish, M. [Fermilab; Moretti, A. [Fermilab; Tollestrup, A. V. [Fermilab; Watts, A. [Fermilab; Zwaska, R. M. [Fermilab; Abrams, R. [MUONS Inc., Batavia; Cummings, M. A.; Dudas, A. [MUONS Inc., Batavia; Johnson, R. P. [MUONS Inc., Batavia; Kazakevich, G. [MUONS Inc., Batavia; Neubauer, M. [MUONS Inc., Batavia; Liu, Q. [Case Western Reserve U.

2017-05-01

We report the R&D of a novel radiation-robust hadron beam profile monitor based on a gas-filled RF cavity for intense neutrino beam experiments. An equivalent RF circuit model was made and simulated to optimize the RF parameter in a wide beam intensity range. As a result, the maximum acceptable beam intensity in the monitor is significantly increased by using a low-quality factor RF cavity. The plan for the demonstration test is set up to prepare for future neutrino beam experiments.

A gamma beam profile imager for ELI-NP Gamma Beam System

Science.gov (United States)

Cardarelli, P.; Paternò, G.; Di Domenico, G.; Consoli, E.; Marziani, M.; Andreotti, M.; Evangelisti, F.; Squerzanti, S.; Gambaccini, M.; Albergo, S.; Cappello, G.; Tricomi, A.; Veltri, M.; Adriani, O.; Borgheresi, R.; Graziani, G.; Passaleva, G.; Serban, A.; Starodubtsev, O.; Variola, A.; Palumbo, L.

2018-06-01

The Gamma Beam System of ELI-Nuclear Physics is a high brilliance monochromatic gamma source based on the inverse Compton interaction between an intense high power laser and a bright electron beam with tunable energy. The source, currently being assembled in Magurele (Romania), is designed to provide a beam with tunable average energy ranging from 0.2 to 19.5 MeV, rms energy bandwidth down to 0.5% and flux of about 108 photons/s. The system includes a set of detectors for the diagnostic and complete characterization of the gamma beam. To evaluate the spatial distribution of the beam a gamma beam profile imager is required. For this purpose, a detector based on a scintillator target coupled to a CCD camera was designed and a prototype was tested at INFN-Ferrara laboratories. A set of analytical calculations and Monte Carlo simulations were carried out to optimize the imager design and evaluate the performance expected with ELI-NP gamma beam. In this work the design of the imager is described in detail, as well as the simulation tools used and the results obtained. The simulation parameters were tuned and cross-checked with the experimental measurements carried out on the assembled prototype using the beam from an x-ray tube.

High resolution beam profiling of X-ray free electron laser radiation by polymer imprint development.

Science.gov (United States)

Rösner, Benedikt; Döring, Florian; Ribič, Primož R; Gauthier, David; Principi, Emiliano; Masciovecchio, Claudio; Zangrando, Marco; Vila-Comamala, Joan; De Ninno, Giovanni; David, Christian

2017-11-27

High resolution metrology of beam profiles is presently a major challenge at X-ray free electron lasers. We demonstrate a characterization method based on beam imprints in poly (methyl methacrylate). By immersing the imprints formed at 47.8 eV into organic solvents, the regions exposed to the beam are removed similar to resist development in grayscale lithography. This allows for extending the sensitivity of the method by more than an order of magnitude compared to the established analysis of imprints created solely by ablation. Applying the Beer-Lambert law for absorption, the intensity distribution in a micron-sized focus can be reconstructed from one single shot with a high dynamic range, exceeding 10 3 . The procedure described here allows for beam characterization at free electron lasers revealing even faint beam tails, which are not accessible when using ablation imprint methods. We demonstrate the greatly extended dynamic range on developed imprints taken in focus of conventional Fresnel zone plates and spiral zone plates producing beams with a topological charge.

Beam profiles in the nonwedged direction for dynamic wedges

International Nuclear Information System (INIS)

Lydon, J.M.; Rykers, K.L.

1996-01-01

One feature of the dynamic wedge is the improved flatness of the beam profile in the nonwedged direction when compared to fixed wedges. Profiles in the nonwedged direction for fixed wedges show a fall-off in dose away from the central axis when compared to the open field profile. This study will show that there is no significant difference between open field profiles and nonwedged direction profiles for dynamically wedged beams. The implications are that the dynamic wedge offers an improved dose distribution in the nonwedged direction that can be modelled by approximating the dynamically wedged field to an open field. This is possible as both the profiles and depth doses of the dynamically wedged fields match those of the open fields, if normalized to d max of the same field size. For treatment planning purposes the effective wedge factor (EWF) provides a normalization factor for the open field depth dose data set. Data will be presented to demonstrate that the EWF shows relatively little variation with depth and can be treated as being independent of field size in the nonwedged direction. (author)

Beam profile measurements using nonimaging gamma optics

International Nuclear Information System (INIS)

Norem, J.; Dawson, J.; Haberichter, W.; Lam, R.; Reed, L.; Yang, X.F.; Spencer, J.

1995-01-01

High energy photons produced from bremsstrahlung foils, Compton scattering or beamstrahlung from high energy e + e - collisions can be used to measure beam profiles using nonimaging optics. We describe the method and its limitations (resolution, backgrounds etc.), as well as the apparatus required to implement it. Data from a low energy test run is described as well as other possible applications, such as a 250+250 GeV linear collider and possible experiments with existing beams. (orig.)

Beam profile measurement of ES-200 using secondary electron emission monitor

Directory of Open Access Journals (Sweden)

E Ebrahimi Basabi

2015-09-01

Full Text Available Up to now, different designs have been introduced for measurement beam profile accelerators. Secondary electron emission monitors (SEM are one of these devices which have been used for this purpose. In this work, a SEM has been constructed to measure beam profile of ES-200 accelerator, a proton electrostatic accelerator which is installed at SBU. Profile grid for both planes designed with 16 wires which are insulated relative to each other. The particles with maximum energy of 200 keV and maximum current of 400 μA are stopped in copper wires. Each of the wires has an individual current-to-voltage amplifier. With a multiplexer, the analogue values are transported to an ADC. The ADCs are read out by a microcontroller and finally profile of beam shows by a user interface program

2-D Low Energy Electron Beam Profile Measurement Based on Computer Tomography Algorithm with Multi-Wire Scanner

CERN Document Server

Yu, Nengjie; Li Qing Feng; Tang, Chuan-Xiang; Zheng, Shuxin

2005-01-01

A new method for low energy electron beam profile measurement is advanced, which presents a full 2-D beam profile distribution other than the traditional 2-D beam profile distribution given by 1-D vertical and horizontal beam profiles. The method is based on the CT (Computer Tomography) algorithm. Multi-sets of data about the 1-D beam profile projections are attained by rotating the multi-wire scanner. Then a 2-D beam profile is reconstructed from these projections with CT algorithm. The principle of this method is presented. The simulation and the experiment results are compared and analyzed in detail.

Development of a high-resolution electron-beam profile monitor using Fresnel zone plates

International Nuclear Information System (INIS)

Nakamura, Norio; Sakai, Hiroshi; Muto, Toshiya; Hayano, Hitoshi

2004-01-01

We present a high-resolution and real-time beam profile monitor using Fresnel zone plates (FZPs) developed in the KEK-ATF damping ring. The monitor system has an X-ray imaging optics with two FZPs. In this monitor, the synchrotron radiation from the electron beam at the bending magnet is monochromatized by a crystal monochromator and the transverse electron beam image is twenty-times magnified by the two FZPs and detected on an X-ray CCD camera. The expected spatial resolution for the selected photon energy of 3.235 keV is less than 1 μm. With the beam profile monitor, we succeeded in obtaining a clear electron-beam image and measuring the extremely small beam size less than 10 μm. It is greatly expected that the beam profile monitor will be used in high-brilliance light sources and low-emittance accelerators. (author)

Beam diagnostics using transition radiation produced by a 100 Mev electron beam

International Nuclear Information System (INIS)

Jablonka, M.; Leroy, J.; Hanus, X.; Derost, J.C.; Wartski, L.

1991-01-01

We report on several experiments using the optical transition radiation (OTR) produced by a 100 MeV electron beam. In using a sensitive video camera coupled with a digital image processing system an accurate and simple beam profile monitor has been devised. In measuring with a photo-multiplier the radiation emitted in a small solid angle around the direction of the OTR emission, a signal very sensitive to beam energy variations has been obtained. These experiments have been carried out on the Saclay ALS linac

Experimental three-dimensional beam profiling and modeling of a terahertz beam generated from a two-color air plasma

DEFF Research Database (Denmark)

Pedersen, Pernille Klarskov; Strikwerda, Andrew; Iwaszczuk, Krzysztof

2013-01-01

a sharp, conical intensity profile resembling a donut, and in the focal region the beam collapses to a central, Lorentz-shaped profile. The Lorentzian intensity profile in the focal region can be explained by considering the frequency-dependent spot size derived from measurements of the Gouy phase shift...... in the focal region, and the transition from the donut profile to a central peak is consistent with propagation of a Bessel–Gauss beam, as shown by simulations based on a recent transient photocurrent model (You et al 2012 Phys. Rev. Lett. 109 183902). We combine our measurements to the first full 3D...

Fast ion profiles during neutral beam and lower hybrid heating

International Nuclear Information System (INIS)

Heidbrink, W.W.; Strachan, J.D.; Bell, R.E.; Cavallo, A.; Motley, R.; Schilling, G.; Stevens, J.; Wilson, J.R.

1985-07-01

Profiles of the d(d,p)t fusion reaction are measured in the PLT tokamak using an array of collimated 3 MeV proton detectors. During deuterium neutral beam injection, the emission profile indicates that the beam deposition is at least as narrow as predicted by a bounce-averaged Fokker-Planck code. The fast ion tail formed by lower hybrid waves (at densities above the critical density for current drive) also peaks strongly near the magnetic axis

A multiwire secondary emission profile monitor for small emittance beams

International Nuclear Information System (INIS)

Chehab, R.; Bonnard, J.; Humbert, G.; Leblond, B.; Saury, J.L.

1985-01-01

A secondary emission monitor using two multiwire grids separated by a positively biased collector has been constructed and tested with a 1 GeV electron beam at the Orsay Linac. The monitor installed just before the electron-positron converter has 8 gold-plated-tungsten wires of 0.1 mm diameter equally spaced 0.2 mm apart in each plane. Each wire is connected with an integrator using a low-bias current operational amplifier. The wire planes and the collector are moved into the beam by a stepping motor : that allows beam-position verification. We measured narrow profiles for 1 Amp peak current pulses of 30 nanoseconds width. Profiles are displayed on a scope and allow emittance determination by the three gradient method. Such a monitor is very useful to control the electron beam position and dimensions on the converter, because the positron source dimensions are rather bigger than those of the incident beam and the geometrical acceptance of the positron Linac is limited

A laser-based beam profile monitor for the SLC/SLD interaction region

International Nuclear Information System (INIS)

Alley, R.; Arnett, D.; Bong, E.; Colocho, W.; Frisch, J.; Horton-Smith, S.; Inman, W.; Jobe, K.; Kotseroglou, T.; McCormick, D.; Nelson, J.; Scheeff, M.; Wagner, S.; Ross, M.C.

1996-01-01

Beam size estimates made using beam-beam deflections are used for optimization of the Stanford linear collider (SLC) electron-positron beam sizes. Typical beam sizes and intensities expected for 1996 operations are 2.1 x 0.6 μm (x, y) at 4.0.10 10 particles per pulse. Conventional profile monitors, such as scanning wires, fail at charge densities well below this. The laser-based profile monitor uses a finely-focused 350-nm wavelength tripled YLF laser pulse that traverses the particle beam path about 29 cm away from the e + /e - IP. Compton scattered photons and degraded e + /e - are detected as the beam is steered across the laser pulse. The laser pulse has a transverse size of 380 nm and a Rayleigh range of about 5 μm. (orig.)

SU-F-I-76: Fluoroscopic X-Ray Beam Profiles for Spectra Incorporating Copper Filtration

Energy Technology Data Exchange (ETDEWEB)

Wunderle, K [Cleveland Clinic Foundation, Cleveland, OH (United States); Wayne State University School of Medicine, Detroit, MI (United States); Godley, A; Shen, Z; Dong, F [Cleveland Clinic Foundation, Cleveland, OH (United States); Rakowski, J [Wayne State University School of Medicine, Detroit, MI (United States)

2016-06-15

Purpose: The purpose of this investigation is to characterize and quantify X-ray beam profiles for fluoroscopic x-ray beam spectra incorporating spectral (copper) filtration. Methods: A PTW (Freiburg, Germany) type 60016 silicon diode detector and PTW MP3 water tank were used to measure X-ray beam profiles for 60, 80, 100 and 120 kVp x-ray beams at five different copper filtration thicknesses ranging from 0–0.9 mm at 22 and 42 cm fields of view and depths of 1, 5, and 10 cm in both the anode-cathode axis (inplane) and cross-plane directions. All measurements were acquired on a Siemens (Erlangen, Germany) Artis ZeeGo fluoroscope inverted from the typical orientation providing an x-ray beam originating from above the water surface with the water level set at 60 cm from the focal spot. Results: X-ray beam profiles for beam spectra without copper filtration compared well to previously published data by Fetterly et al. [Med Phys, 28, 205 (2001)]. Our data collection benefited from the geometric orientation of the fluoroscope, providing a beam perpendicular to the tank water surface, rather than through a thin side wall as did the previously mentioned study. Profiles for beams with copper filtration were obtained which have not been previously investigated and published. Beam profiles in the anode-cathode axis near the surface and at lower x-ray energy exhibited substantial heel effect, which became less pronounced at greater depth. At higher energy with copper filtration in the beam, the dose falloff out-of-field became less pronounced, as would be anticipated given higher scatter photon energy. Conclusion: The x-ray beam profile data for the fluoroscopic x-ray beams incorporating copper filtration are intended for use as reference data for estimating doses to organs or soft tissue, including fetal dose, involving similar beam qualities or for comparison with mathematical models.

Influence of laser beam profiles on received power fluctuation

Science.gov (United States)

Dordova, Lucie; Diblik, Jan

2011-09-01

Gaussian beam is very often used for the transmission of information in optical wireless links. The usage of this optical beam has its advantages and, of course, disadvantages. This work focuses on possibilities of using laser beams with different distribution of optical intensity - Top Hat beam. Creation of the optical beam with selected optical intensity profile will be briefly described. Optical beams will propagate through the "clear" and stationary atmosphere in the experimental part of this work. These results will be compared with the data obtained after a laser beam is passed through the turbulent and attenuated atmosphere. We will use an ultrasound fog generator for laser beam attenuation testing. To create the turbulence, infra radiators will be applied. Particular results obtained from different atmospheric conditions will be compared and using different types of optical beams will be assessed.

Effect of 3D Polarization profiles on polarization measurements and colliding beam experiments

Energy Technology Data Exchange (ETDEWEB)

Fischer, W.; Bazilevsky, A.

2011-08-18

The development of polarization profiles are the primary reason for the loss of average polarization. Polarization profiles have been parametrized with a Gaussian distribution. We derive the effect of 3-dimensional polarization profiles on the measured polarization in polarimeters, as well as the observed polarization and the figure of merit in single and double spin experiments. Examples from RHIC are provided. The Relativistic Heavy Ion Collider (RHIC) is the only collider of spin polarized protons. During beam acceleration and storage profiles of the polarization P develop, which affect the polarization measured in a polarimeter, and the polarization and figure of merit (FOM) in colliding beam experiments. We calculate these for profiles in all dimensions, and give examples for RHIC. Like in RHIC we call the two colliding beams Blue and Yellow. We use the overbar to designate intensity-weighted averages in polarimeters (e.g. {bar P}), and angle brackets to designate luminosity-weighted averages in colliding beam experiments (e.g.

).

Effect of 3D Polarization profiles on polarization measurements and colliding beam experiments

International Nuclear Information System (INIS)

Fischer, W.; Bazilevsky, A.

2011-01-01

The development of polarization profiles are the primary reason for the loss of average polarization. Polarization profiles have been parametrized with a Gaussian distribution. We derive the effect of 3-dimensional polarization profiles on the measured polarization in polarimeters, as well as the observed polarization and the figure of merit in single and double spin experiments. Examples from RHIC are provided. The Relativistic Heavy Ion Collider (RHIC) is the only collider of spin polarized protons. During beam acceleration and storage profiles of the polarization P develop, which affect the polarization measured in a polarimeter, and the polarization and figure of merit (FOM) in colliding beam experiments. We calculate these for profiles in all dimensions, and give examples for RHIC. Like in RHIC we call the two colliding beams Blue and Yellow. We use the overbar to designate intensity-weighted averages in polarimeters (e.g. (bar P)), and angle brackets to designate luminosity-weighted averages in colliding beam experiments (e.g. ).

Beam Profile Measurement with Flying Wires at the Fermilab Recycler Ring

CERN Document Server

Hu, Martin; Krider, John; Lorman, Eugene; Marchionni, Alberto; Pishchalnikov, Yu M; Pordes, Stephen; Slimmer, David; Wilson, Peter R; Zagel, James

2005-01-01

The Fermilab Recycler Ring is a high vacuum fixed energy antiproton storage ring with stochastic and electron cooling systems. Flying wires were installed at the Fermilab Recycler Ring for transverse beam profile measurement. The following note describes the system configuration, calibration and resolution of the flying wire system, as well as analysis of the transverse beam profile in the presence of both cooling systems.

Design of a D-alpha beam-ion profile diagnostic

International Nuclear Information System (INIS)

Luo, Y.; Heidbrink, W.W.; Burrell, K.H.

2004-01-01

Injected neutral beams ionize to create a population of beam ions. As they orbit around the tokamak and pass through the heating beams, some beam ions re-neutralize and emit D-alpha light. The intensity of this emission is weak compared to the signals from the injected neutrals, the warm (halo) neutrals, and the edge recombination neutrals but, for a favorable viewing geometry, the emission is Doppler shifted away from these bright interfering signals. Preliminary data from the DIII-D tokamak show that signals from re-neutralized beam ions have already been detected. A three-channel prototype instrument consisting of a spectrometer, mask, camera lenses, and frame-transfer charge coupled device is under development for measurements of the spatial profile of the beam ions

Development of a reusable beam profile analyzer for laser accelerated proton beams

Energy Technology Data Exchange (ETDEWEB)

Frydrych, Simon; Busold, Simon; Deppert, Oliver; Roth, Markus [Technische Univ. Darmstadt (Germany). Inst. fuer Kernphysik

2013-07-01

At the GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, proton beams are generated with the PHELIX laser system through target normal sheath acceleration (TNSA). Within 1 ps, 10{sup 13} protons are produced with an exponential energy spectrum up to 50 MeV. For characterisation, the spatial beam profile is currently detected by a stack of radiochromatic films (RCF). These are blued depending on the beam intensity. One disadvantage of RCFs is its one-time usability. Therefore, they shall be replaced by a scintillator array. To ensure the longest possible shelf life of this new detector, the scintillator material used must be very robust against radiation damage. Also a point of current research is the maximal amount of particles, which can be detected separately.

Fast-scan monitor examines neutral-beam ion-density profile

International Nuclear Information System (INIS)

Anon.

1978-01-01

All of the magnetic mirror confinement fusion experiments at LLL and at other laboratories depend on pulsed, energetic neutral-beam injection for fueling and imparting energy to the trapped plasma for density build-up and stability studies. It is vital to be able to monitor how well the injected ion beam is aimed and focused. To do this, we have designed an ion-beam current-density profile monitor that uses a commercial minimodular data acquisition system. Our prototype model monitors a single 20-kV, 50-A, 10-ms beam. However, the method is applicable to any number of beams with similar sampling target arrays. Also, the electronics can be switched to monitor any one of several target collectors

The measurement of neutral beam thermal profiles on 'V'-shaped calorimeters

International Nuclear Information System (INIS)

Kamperschroer, J.H.; Lagin, L.J.; Silber, K.

1995-01-01

It is customary in high power neutral beam systems to use a V-shaped calorimeter to stop and measure the beam. With proper instrumentation, it is possible to determine both the neutral beam power and divergence. By utilizing a near-grazing angle of incidence, the area over which the beam is in contact with the surface is increased, thereby decreasing the power density over the case of normal incidence. Thermocouples on the back of the calorimeter, in conjunction with real time fitting algorithms, are used to deduce the divergence from the thermal profile. This measurement implicitly assumes that the measured profile corresponds to that of the incident beam. It is shown that such is not the case. Energetic particle reflection at near-grazing angle causes the thermal profile on the calorimeter to be more peaked than the incident distribution. The implications of this on the non-linear multiple regression technique of determining the divergence are discussed. With the aid of a reflection model, developed and applied to the beam from a typical TFTR ion source, it is shown that a peaked power density can be modelled. Neural networks are being studied as a means of supplanting the older regression technique of measuring divergence. Y-direction divergences have been successfully derived using a one-dimensional neural network

Electron beam based transversal profile measurements of intense ion beams

International Nuclear Information System (INIS)

El Moussati, Said

2014-01-01

A non-invasive diagnostic method for the experimental determination of the transverse profile of an intense ion beam has been developed and investigated theoretically as well as experimentally within the framework of the present work. The method is based on the deflection of electrons when passing the electromagnetic field of an ion beam. To achieve this an electron beam is employed with a specifically prepared transversal profile. This distinguish this method from similar ones which use thin electron beams for scanning the electromagnetic field [Roy et al. 2005; Blockland10]. The diagnostic method presented in this work will be subsequently called ''Electron-Beam-Imaging'' (EBI). First of all the influence of the electromagnetic field of the ion beam on the electrons has been theoretically analyzed. It was found that the magnetic field causes only a shift of the electrons along the ion beam axis, while the electric field only causes a shift in a plane transverse to the ion beam. Moreover, in the non-relativistic case the magnetic force is significantly smaller than the Coulomb one and the electrons suffer due to the magnetic field just a shift and continue to move parallel to their initial trajectory. Under the influence of the electric field, the electrons move away from the ion beam axis, their resulting trajectory shows a specific angle compared to the original direction. This deflection angle practically depends just on the electric field of the ion beam. Thus the magnetic field has been neglected when analysing the experimental data. The theoretical model provides a relationship between the deflection angle of the electrons and the charge distribution in the cross section of the ion beam. The model however only can be applied for small deflection angles. This implies a relationship between the line-charge density of the ion beam and the initial kinetic energy of the electrons. Numerical investigations have been carried out to clarify the

Transverse beam profile measurements with slit scanner and Faraday cup at REX-ISOLDE

CERN Document Server

Cantero, E D; Lanaia, D; Sosa, A; Voulot, D

2014-01-01

The transverse profiles for the HIE-ISOLDE beams will be measured using a system composed of a scanning slit and a Faraday cup. A validation test of the proposed device was performed using the REX-ISOLDE stable beam and a prototype diagnostic box designed for HIE-ISOLDE. The slit used for this test was very thin (0.2 mm width), but still fairly good profiles could be obtained for beams with total current of around 20 pA (typical beam intensity during normal set-up procedures for REX-ISOLDE).

Micro-strip Metal Foil Detectors for the Beam Profile Monitoring

CERN Document Server

Pugatch, V M; Fedorovitch, O A; Mikhailenko, A V; Prystupa, S V; Pylypchenko, Y

2005-01-01

The Micro-strip Metal Foil Detectors (MMFD) designed and used for the Beam Profile Monitoring (BPM) are discussed. Fast particles hitting a metal strip initiate Secondary Electron Emission (SEE) which occurs at 10 - 50 nm surface layers of a strip. The SEE yield is measured by a sensitive Charge Integrator with built-in current-to-frequency converter (1 Hz per 1 fA). The MMFD (deposited onto the 20 μm thick Si-wafer) with 32 Al strips (10 μm wide, 32 μm pitch) has been used for the BPM of the 32 MeV alpha-particle beam at the MPIfK (Heidelberg) Tandem generator for Single-Event-Upset studies of the BEETLE micro-chip. Similar MMFD (0.5 μm thick Ni-strips) with totally removed Si-wafer (by plasma-chemistry, at the working area of 8 x 10 mm2) has been applied for the on-line X-ray BPM at the HASYLAB (DESY). The number of photons (11.3 GeV, mean X-ray energy 18 keV) producing out of a strip a single SEE was evaluated as (1.5 ±0.5)* 104. MMFD has demonstrated stable...

Radiographic film dosimetry of proton beams for depth‐dose constancy check and beam profile measurement

Science.gov (United States)

Teran, Anthony; Ghebremedhin, Abiel; Johnson, Matt; Patyal, Baldev

2015-01-01

Radiographic film dosimetry suffers from its energy dependence in proton dosimetry. This study sought to develop a method of measuring proton beams by the film and to evaluate film response to proton beams for the constancy check of depth dose (DD). It also evaluated the film for profile measurements. To achieve this goal, from DDs measured by film and ion chamber (IC), calibration factors (ratios of dose measured by IC to film responses) as a function of depth in a phantom were obtained. These factors imply variable slopes (with proton energy and depth) of linear characteristic curves that relate film response to dose. We derived a calibration method that enables utilization of the factors for acquisition of dose from film density measured at later dates by adapting to a potentially altered processor condition. To test this model, the characteristic curve was obtained by using EDR2 film and in‐phantom film dosimetry in parallel with a 149.65 MeV proton beam, using the method. An additional validation of the model was performed by concurrent film and IC measurement perpendicular to the beam at various depths. Beam profile measurements by the film were also evaluated at the center of beam modulation. In order to interpret and ascertain the film dosimetry, Monte Carlos simulation of the beam was performed, calculating the proton fluence spectrum along depths and off‐axis distances. By multiplying respective stopping powers to the spectrum, doses to film and water were calculated. The ratio of film dose to water dose was evaluated. Results are as follows. The characteristic curve proved the assumed linearity. The measured DD approached that of IC, but near the end of the spread‐out Bragg peak (SOBP), a spurious peak was observed due to the mismatch of distal edge between the calibration and measurement films. The width of SOBP and the proximal edge were both reproducible within a maximum of 5 mm; the distal edge was reproducible within 1 mm. At 5 cm depth, the

Pain sensitivity profiles in patients with advanced knee osteoarthritis

Science.gov (United States)

Frey-Law, Laura A.; Bohr, Nicole L.; Sluka, Kathleen A.; Herr, Keela; Clark, Charles R.; Noiseux, Nicolas O.; Callaghan, John J; Zimmerman, M Bridget; Rakel, Barbara A.

2016-01-01

The development of patient profiles to subgroup individuals on a variety of variables has gained attention as a potential means to better inform clinical decision-making. Patterns of pain sensitivity response specific to quantitative sensory testing (QST) modality have been demonstrated in healthy subjects. It has not been determined if these patterns persist in a knee osteoarthritis population. In a sample of 218 participants, 19 QST measures along with pain, psychological factors, self-reported function, and quality of life were assessed prior to total knee arthroplasty. Component analysis was used to identify commonalities across the 19 QST assessments to produce standardized pain sensitivity factors. Cluster analysis then grouped individuals that exhibited similar patterns of standardized pain sensitivity component scores. The QST resulted in four pain sensitivity components: heat, punctate, temporal summation, and pressure. Cluster analysis resulted in five pain sensitivity profiles: a “low pressure pain” group, an “average pain” group, and three “high pain” sensitivity groups who were sensitive to different modalities (punctate, heat, and temporal summation). Pain and function differed between pain sensitivity profiles, along with sex distribution; however no differences in OA grade, medication use, or psychological traits were found. Residualizing QST data by age and sex resulted in similar components and pain sensitivity profiles. Further, these profiles are surprisingly similar to those reported in healthy populations suggesting that individual differences in pain sensitivity are a robust finding even in an older population with significant disease. PMID:27152688

A high resolution, single bunch, beam profile monitor

International Nuclear Information System (INIS)

Norem, J.

1992-01-01

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

A high resolution beam profile monitor using Bremsstrahlung

International Nuclear Information System (INIS)

Norem, J.

1988-01-01

The development of efficient high energy linear colliders in the 1 TeV range requires final focus systems capable of producing beam spot sizes on the order of 1--20 nm, about three orders of magnitude smaller than those produced at the SLC. Although beam line designs exist which can, in principle, produce the required optics, the construction of quadrupoles with the size and precision required will be challenging. Field errors in these quads must be small and should be verified experimentally, which is difficult with existing technology. This paper describes a proposal to use bremsstrahlung from heavy targets to measure high energy beam profiles and positions with a resolution approaching a few nm. The method is also applicable to tests of other final focus systems (flat beams, plasma lenses) at lower energies. 6 refs., 3 figs., 1 tab

Beam Profile Disturbances from Implantable Pacemakers or Implantable Cardioverter-Defibrillator Interactions

Energy Technology Data Exchange (ETDEWEB)

Gossman, Michael S., E-mail: mgossman@tsrcc.com [Tri-State Regional Cancer Center, Medical Physics Section, Ashland, KY (United States); Comprehensive Heart and Vascular Associates, Heart and Vascular Center, Ashland, KY (United States); Medtronic, Inc., External Research Program, Mounds View, MN (United States); Nagra, Bipinpreet; Graves-Calhoun, Alison; Wilkinson, Jeffrey [Tri-State Regional Cancer Center, Medical Physics Section, Ashland, KY (United States); Comprehensive Heart and Vascular Associates, Heart and Vascular Center, Ashland, KY (United States); Medtronic, Inc., External Research Program, Mounds View, MN (United States)

2011-01-01

The medical community is advocating for progressive improvement in the design of implantable cardioverter-defibrillators and implantable pacemakers to accommodate elevations in dose limitation criteria. With advancement already made for magnetic resonance imaging compatibility in some, a greater need is present to inform the radiation oncologist and medical physicist regarding treatment planning beam profile changes when such devices are in the field of a therapeutic radiation beam. Treatment plan modeling was conducted to simulate effects induced by Medtronic, Inc.-manufactured devices on therapeutic radiation beams. As a continuation of grant-supported research, we show that radial and transverse open beam profiles of a medical accelerator were altered when compared with profiles resulting when implantable pacemakers and cardioverter-defibrillators are placed directly in the beam. Results are markedly different between the 2 devices in the axial plane and the sagittal planes. Vast differences are also presented for the therapeutic beams at 6-MV and 18-MV x-ray energies. Maximum changes in percentage depth dose are observed for the implantable cardioverter-defibrillator as 9.3% at 6 MV and 10.1% at 18 MV, with worst distance to agreement of isodose lines at 2.3 cm and 1.3 cm, respectively. For the implantable pacemaker, the maximum changes in percentage depth dose were observed as 10.7% at 6 MV and 6.9% at 18 MV, with worst distance to agreement of isodose lines at 2.5 cm and 1.9 cm, respectively. No differences were discernible for the defibrillation leads and the pacing lead.

A Low-cost Beam Profiler Based On Cerium-doped Silica Fibers

Science.gov (United States)

Potkins, David Edward; Braccini, Saverio; Nesteruk, Konrad Pawel; Carzaniga, Tommaso Stefano; Vedda, Anna; Chiodini, Norberto; Timmermans, Jacob; Melanson, Stephane; Dehnel, Morgan Patrick

A beam profiler called the Universal Beam Monitor (UniBEaM) has been developed by D-Pace Inc. (Canada) and the Albert Einstein Center for Fundamental Physics, Laboratory for High Energy Physics, University of Bern (Switzerland). The device is based on passing 100 to 600 micron cerium-doped optical fibers through a particle beam. Visible scintillation light from the sensor fibers is transmitted over distances of tens of meters to the light sensors with minimal signal loss and no susceptibility to electromagnetic fields. The probe has an insertion length of only 70 mm. The software plots the beam intensity distribution in the horizontal and vertical planes, and calculates the beam location and integrated profile area, which correlates well with total beam current. UniBEaM has a large dynamic range, operating with beam currents of ∼pA to mA, and a large range of particle kinetic energies of ∼keV to GeV, depending on the absorbed power density. Test data are presented for H- beams at 25keV for 500 μA, and H+ beams at 18MeV for 50pA to 10 μA. Maximum absorbed power density of the optical fiber before thermal damage is discussed in relation to dE/dx energy deposition as a function of particle type and kinetic energy. UniBEaM is well suited for a wide variety of beamlines including discovery science applications, radio-pharmaceutical production, hadron therapy, industrial ion beam applications including ion implantation, industrial electron beams, and ion source testing.

Statistically sound evaluation of trace element depth profiles by ion beam analysis

International Nuclear Information System (INIS)

Schmid, K.; Toussaint, U. von

2012-01-01

This paper presents the underlying physics and statistical models that are used in the newly developed program NRADC for fully automated deconvolution of trace level impurity depth profiles from ion beam data. The program applies Bayesian statistics to find the most probable depth profile given ion beam data measured at different energies and angles for a single sample. Limiting the analysis to % level amounts of material allows one to linearize the forward calculation of ion beam data which greatly improves the computation speed. This allows for the first time to apply the maximum likelihood approach to both the fitting of the experimental data and the determination of confidence intervals of the depth profiles for real world applications. The different steps during the automated deconvolution will be exemplified by applying the program to artificial and real experimental data.

A feasibility study of Dynamic Phantom scanner for quality assurance of photon beam profiles at various gantry angles.

Science.gov (United States)

Zhang, Yunkai; Hsi, Wen C; Chu, James C H; Bernard, Damian B; Abrams, Ross A

2005-01-01

The effect of gantry rotation on beam profiles of photon and electron beams is an important issue in quality assurance for radiotherapy. To address variations in the profiles of photon and electron beams at different gantry angles, a Dynamic Phantom scanner composed of a 20 x 12 x 6 cm3 scanning Lucite block was designed as a cross-beam-profile scanner. To our knowledge, differences between scanned profiles acquired at different gantry angles with a small size Lucite block and those acquired a full-size (60 x 60 x 50 cm3) water phantom have not been previously investigated. We therefore performed a feasibility study for a first prototype Dynamic Phantom scanner without a gantry attachment mount. Radiation beams from a Varian LINAC 21EX and 2100C were used. Photon beams (6 MV and 18 MV) were shaped by either collimator jaws or a Varian 120 Multileaf (MLC) collimator, and electron beams (6 MeV, 12 MeV, and 20 MeV) were shaped by a treatment cone. To investigate the effect on profiles by using a Lucite block, a quantitative comparison of scanned profiles with the Dynamic Phantom and a full-size water phantom was first performed at a 0 degrees gantry angle for both photon and electron beams. For photon beam profiles defined by jaws at 1.0 cm and 5.0 cm depths of Lucite (i.e., at 1.1 cm and 5.7 cm depth of water), a good agreement (less than 1% variation) inside the field edge was observed between profiles scanned with the Dynamic Phantom and with a water phantom. The use of Lucite in the Dynamic Phantom resulted in reduced penumbra width (about 0.5 mm out of 5 mm to 8mm) and reduced (1% to 2%) scatter dose beyond the field edges for both 6 MV and 18 MV beams, compared with the water phantom scanner. For profiles of the MLC-shaped 6 MV photon beam, a similar agreement was observed. For profiles of electron beams scanned at 2.9 cm depth of Lucite (i.e., at 3.3 cm depth of water), larger disagreements in profiles (3% to 4%) and penumbra width (3 mm to 4 mm out of 12 mm

Gas dynamics considerations in a non-invasive profile monitor for charged particle beams

CERN Document Server

Tzoganis, Vasilis; Welsch, Carsten P

2014-01-01

A non-invasive, gas jet-based, beam profile monitor has been developed in the QUASAR Group at the Cockcroft Institute, UK. This allows on-line measurement of the 2-dimensional transverse profile of particle beams with negligible disturbance to either primary beam or accelerator vacuum. The monitor is suitable for use with beams across a wide range of energies and intensities. In this setup a nozzle-skimmer system shapes a thin supersonic gas jet into a curtain. However, the small dimensions of the gas inlet nozzle and subsequent skimmers were shown to be the cause of many operational problems. In this paper, the dynamics of gas jet formation transport and shaping is discussed before an image-processing based alignment technique is introduced. Furthermore, experimental results obtained with a 5 keV electron beam are discussed and the effects of gas stagnation pressure on the acquired beam are presented.

A high resolution wire scanner beam profile monitor with a microprocessor data acquisition system

International Nuclear Information System (INIS)

Cutler, R.I.; Mohr, D.L.; Whittaker, J.K.; Yoder, N.R.

1983-01-01

A beam profile monitor has been constructed for the NBS-LANL Racetrack Microtron. The monitor consists of two perpendicular 30 μm diameter carbon wires that are driven through an electron beam by a pneumatic actuator. A long-lifetime, electroformed nickel bellows is used for the linear-motion vacuum feedthrough. Secondary emission current from the wires and a signal from a transducer measuring the position of the wires are simultaneously digitized by a microprocessor to yield beam current density profiles in two dimensions. The wire scanner is designed for use with both pulsed and cw beams

A feasibility study of the Dynamic Phantom scanner for quality assurance of beam profiles at various gantry angles

Science.gov (United States)

Zhang, Yunkai; Hsi, Wen C.; Chu, James C.H.; Bernard, Damian B.; Abrams, Ross A.

2005-01-01

The effect of gantry rotation on beam profiles of photon and electron beams is an important issue in quality assurance for radiotherapy. To address variations in the profiles of photon and electron beams at different gantry angles, a Dynamic Phantom scanner composed of a 20×12×6 cm3 scanning Lucite block was designed as a cross‐beam‐profile scanner. To our knowledge, differences between scanned profiles acquired at different gantry angles with a small size Lucite block and those acquired a full‐size (60×60×50 cm3) water phantom have not been previously investigated. We therefore performed a feasibility study for a first prototype Dynamic Phantom scanner without a gantry attachment mount. Radiation beams from a Varian LINAC 21EX and 2100C were used. Photon beams (6 MV and 18 MV) were shaped by either collimator jaws or a Varian 120 Multileaf (MLC) collimator, and electron beams (6 MeV, 12 MeV, and 20 MeV) were shaped by a treatment cone. To investigate the effect on profiles by using a Lucite block, a quantitative comparison of scanned profiles with the Dynamic Phantom and a full‐size water phantom was first performed at a 0° gantry angle for both photon and electron beams. For photon beam profiles defined by jaws at 1.0 cm and 5.0 cm depths of Lucite (i.e., at 1.1 cm and 5.7 cm depth of water), a good agreement (less than 1% variation) inside the field edge was observed between profiles scanned with the Dynamic Phantom and with a water phantom. The use of Lucite in the Dynamic Phantom resulted in reduced penumbra width (about 0.5 mm out of 5 mm to 8 mm) and reduced (1% to 2%) scatter dose beyond the field edges for both 6 MV and 18 MV beams, compared with the water phantom scanner. For profiles of the MLC‐shaped 6 MV photon beam, a similar agreement was observed. For profiles of electron beams scanned at 2.9 cm depth of Lucite (i.e., at 3.3 cm depth of water), larger disagreements in profiles (3% to 4%) and penumbra width (3 mm to 4 mm out of 12 mm

Moving gantry method for electron beam dose profile measurement at extended source-to-surface distances.

Science.gov (United States)

Fekete, Gábor; Fodor, Emese; Pesznyák, Csilla

2015-03-08

A novel method has been put forward for very large electron beam profile measurement. With this method, absorbed dose profiles can be measured at any depth in a solid phantom for total skin electron therapy. Electron beam dose profiles were collected with two different methods. Profile measurements were performed at 0.2 and 1.2 cm depths with a parallel plate and a thimble chamber, respectively. 108cm × 108 cm and 45 cm × 45 cm projected size electron beams were scanned by vertically moving phantom and detector at 300 cm source-to-surface distance with 90° and 270° gantry angles. The profiles collected this way were used as reference. Afterwards, the phantom was fixed on the central axis and the gantry was rotated with certain angular steps. After applying correction for the different source-to-detector distances and incidence of angle, the profiles measured in the two different setups were compared. Correction formalism has been developed. The agreement between the cross profiles taken at the depth of maximum dose with the 'classical' scanning and with the new moving gantry method was better than 0.5 % in the measuring range from zero to 71.9 cm. Inverse square and attenuation corrections had to be applied. The profiles measured with the parallel plate chamber agree better than 1%, except for the penumbra region, where the maximum difference is 1.5%. With the moving gantry method, very large electron field profiles can be measured at any depth in a solid phantom with high accuracy and reproducibility and with much less time per step. No special instrumentation is needed. The method can be used for commissioning of very large electron beams for computer-assisted treatment planning, for designing beam modifiers to improve dose uniformity, and for verification of computed dose profiles.

Evaluation of the 3-GeV proton beam profile at the spallation target of the JSNS

Energy Technology Data Exchange (ETDEWEB)

Meigo, Shin-ichiro [Japan Atomic Energy Research Institute, Tokai, Naka-gun, Ibaraki 319-1195 (Japan)]. E-mail: meigo.shinichiro@jaea.go.jp; Noda, Fumiaki [Japan Atomic Energy Research Institute, Tokai, Naka-gun, Ibaraki 319-1195 (Japan); Ishikura, Syuichi [Japan Atomic Energy Research Institute, Tokai, Naka-gun, Ibaraki 319-1195 (Japan); Futakawa, Masatoshi [Japan Atomic Energy Research Institute, Tokai, Naka-gun, Ibaraki 319-1195 (Japan); Sakamoto, Shinichi [Japan Atomic Energy Research Institute, Tokai, Naka-gun, Ibaraki 319-1195 (Japan); Ikeda, Yujiro [Japan Atomic Energy Research Institute, Tokai, Naka-gun, Ibaraki 319-1195 (Japan)

2006-06-23

At JSNS, 3-GeV protons beam is delivered from rapid cycling synchrotron (RCS) to the spallation neutron target. In order to reduce the damage of pitting on the target container, the peak current density should be kept as small as possible. In this study, the beam profile at spallation neutron target is evaluated. The phase-space distribution, including the space-charge effect, is calculated with SIMPSONS code. The beam profile on the target is obtained with the transfer matrix from exit of RCS to the target. As for injection to RCS, two methods of correlated and anti-correlated painting are considered. By using anti-correlated painting for injection of beam at RCS, it is found the shape of beam becomes flatter than the distribution by using correlated painting. As other aspect for the study of target, in order to carry out target performance test especially for the study of pitting issue, it is better to have the beam profile variety from the beginning of facility. The adjustable range for the beam profile at the beginning is also studied. Although the beam shape is narrow and the duty is very low, the strong enough peak density is achievable equivalent as 1 MW.

Profiles of an initially perturbed electron beam

International Nuclear Information System (INIS)

Abdelsalam, F.W.

1991-01-01

This paper discusses the solutions for the profiles of an electron beam which is launched into a constant magnetic field with an initial boundary slope and injected with a radius which is greater or less than the cathode radius. It has been found that the outermost electron traces sine waves and executes limited excursions when the initial boundary slope corresponds to angles up to 1 degree, no matter whether the initial radius is 0.90 or 1.10 times the radius of the cathode. For initial inclination angles close to 2 degrees, the beam boundary does not preserve a sinusoidal shape, this statement holds true for focusing magnetic flux densities varying from 200x10 -4 to 700x10 -4 weber per square meter

Parameters affecting profile shape of a high energy low current thin ion beam. Vol. 2

Energy Technology Data Exchange (ETDEWEB)

Abdel Salam, F W; Moustafa, O A; El-Khabeary, H [Accelerators Department, Nuclear Research Center, Atomic Energy Authority, Cairo, (Egypt)

1996-03-01

The shape of the profile of a high energy, low current beam of finite length has beam investigated. The beam profile shape depends on the initial beam radius, beam perveance, atomic mass number, charge state of ions, and beam length. These parameters can affect the relation between the initial beam radius and the corresponding final one. An optimum initial beam radius corresponding to minimum final beam at the target has been formulated and the relation between them is deduced taking account of the space charge effect. The minimum beam radius at the target was found to be equal to 2.3 of the optimum initial radius. It is concluded that in order to obtain a small beam radius at a target placed at a finite distance from an ion source, a beam of a low perveance, low atomic mass number and high number of electronic charge is required. This is an important detection for micro machining applications using the oscillating electron ion source which produces nearly paraxial thin beam of low perveance. 12 figs.

Method of measuring a profile of the density of charged particles in a particle beam

International Nuclear Information System (INIS)

Hyman, L.G.; Jankowski, D.J.

1975-01-01

A profile of the relative density of charged particles in a beam is obtained by disposing a number of rods parallel to each other in a plane perpendicular to the beam and shadowing the beam. A second number of rods is disposed perpendicular to the first rods in a plane perpendicular to the beam and also shadowing the beam. Irradiation of the rods by the beam of charged particles creates radioactive isotopes in a quantity proportional to the number of charged particles incident upon the rods. Measurement of the radioactivity of each of the rods provides a measure of the quantity of radioactive material generated thereby and, together with the location of the rods, provides information sufficient to identify a profile of the density of charged particles in the beam

Determination of the meniscus shape of a negative ion beam from an experimentally obtained beam profile

Science.gov (United States)

Ichikawa, M.; Kojima, A.; Chitarin, G.; Agostinetti, P.; Aprile, D.; Baltador, C.; Barbisan, M.; Delogu, R.; Hiratsuka, J.; Marconato, N.; Nishikiori, R.; Pimazzoni, A.; Sartori, E.; Serianni, G.; Tobari, H.; Umeda, N.; Veltri, P.; Watanabe, K.; Yoshida, M.; Antoni, V.; Kashiwagi, M.

2017-08-01

In order to understand the physics mechanism of a negative ion extraction in negative ion sources, an emission surface of the negative ions around an aperture at a plasma grid, so-called a meniscus, has been analyzed by an inverse calculation of the negative ion trajectory in a two dimensional beam analysis code. In this method, the meniscus is defined as the final position of the negative ion trajectories which are inversely calculated from the measured beam profile to the plasma grid. In a case of the volume-produced negative ions, the calculated meniscus by the inverse calculation was similar to that obtained in conventional beam simulation codes for positive ion extractions such as BEAMORBT and SLACCAD. The negative ion current density was uniform along the meniscus. This indicates that the negative ions produced in the plasma are transported to the plasma grid uniformly as considered in the transportation of the positive ions. However, in a surface production case of negative ions, where the negative ions are generated near the plasma grid with lower work function by seeding cesium, the current density in the peripheral region of the meniscus close to the plasma grid surface was estimated to be 2 times larger than the center region, which suggested that the extraction process of the surface-produced negative ions was much different with that for the positive ions. Because this non-uniform profile of the current density made the meniscus shape strongly concave, the beam extracted from the peripheral region could have a large divergence angle, which might be one of origins of so-called beam halo. This is the first results of the determination of the meniscus based on the experiment, which is useful to improve the prediction of the meniscus shape and heat loads based on the beam trajectories including beam halo.

Electron beam based transversal profile measurements of intense ion beams; Elektronenstrahl-Diagnostik zur Bestimmung vom transversalen Profil intensiver Ionenstrahlen

Energy Technology Data Exchange (ETDEWEB)

El Moussati, Said

2014-11-03

A non-invasive diagnostic method for the experimental determination of the transverse profile of an intense ion beam has been developed and investigated theoretically as well as experimentally within the framework of the present work. The method is based on the deflection of electrons when passing the electromagnetic field of an ion beam. To achieve this an electron beam is employed with a specifically prepared transversal profile. This distinguish this method from similar ones which use thin electron beams for scanning the electromagnetic field [Roy et al. 2005; Blockland10]. The diagnostic method presented in this work will be subsequently called ''Electron-Beam-Imaging'' (EBI). First of all the influence of the electromagnetic field of the ion beam on the electrons has been theoretically analyzed. It was found that the magnetic field causes only a shift of the electrons along the ion beam axis, while the electric field only causes a shift in a plane transverse to the ion beam. Moreover, in the non-relativistic case the magnetic force is significantly smaller than the Coulomb one and the electrons suffer due to the magnetic field just a shift and continue to move parallel to their initial trajectory. Under the influence of the electric field, the electrons move away from the ion beam axis, their resulting trajectory shows a specific angle compared to the original direction. This deflection angle practically depends just on the electric field of the ion beam. Thus the magnetic field has been neglected when analysing the experimental data. The theoretical model provides a relationship between the deflection angle of the electrons and the charge distribution in the cross section of the ion beam. The model however only can be applied for small deflection angles. This implies a relationship between the line-charge density of the ion beam and the initial kinetic energy of the electrons. Numerical investigations have been carried out to clarify the

Ultra-low energy Ar+ beam applied for SIMS depth profile analysis of layered nanostructures

International Nuclear Information System (INIS)

Konarski, P.; Mierzejewska, A.; Iwanejko, I.

2001-01-01

Secondary ion mass spectrometry (SIMS) depth profile analyses of flat layered nanostructures: 10 nm Ta 2 O 3 /Ta and 20 nm (10 x B 4 C/Mo)/Si as well as microparticles of core (illite) - shell (rutile) structure, performed with the use of ultra-low energy ion beam (180-880 eV, Ar + ), are presented. The profiles were obtained using 'mesa' scanning technique and also sample rotation. Depth profile resolution below 1 nanometer was obtained for flat nanostructures. Presented experimental results are compared with Monte Carlo sputtering simulations of analysed structures. A method of finding beam energy, optimal for the best resolution SIMS depth profile analysis, is suggested. (author)

Parallel-hierarchical processing and classification of laser beam profile images based on the GPU-oriented architecture

Science.gov (United States)

Yarovyi, Andrii A.; Timchenko, Leonid I.; Kozhemiako, Volodymyr P.; Kokriatskaia, Nataliya I.; Hamdi, Rami R.; Savchuk, Tamara O.; Kulyk, Oleksandr O.; Surtel, Wojciech; Amirgaliyev, Yedilkhan; Kashaganova, Gulzhan

2017-08-01

The paper deals with a problem of insufficient productivity of existing computer means for large image processing, which do not meet modern requirements posed by resource-intensive computing tasks of laser beam profiling. The research concentrated on one of the profiling problems, namely, real-time processing of spot images of the laser beam profile. Development of a theory of parallel-hierarchic transformation allowed to produce models for high-performance parallel-hierarchical processes, as well as algorithms and software for their implementation based on the GPU-oriented architecture using GPGPU technologies. The analyzed performance of suggested computerized tools for processing and classification of laser beam profile images allows to perform real-time processing of dynamic images of various sizes.

Development of residual gas ionization profile monitor for high intensity proton beams

CERN Document Server

Sato, Y; Hirose, E; Ieiri, M; Igarashi, Y; Inaba, S; Katoh, Y; Minakawa, M; Noumi, H; Saitó, M; Suzuki, Y; Takahashi, H; Takasaki, M; Tanaka, K; Toyoda, A; Yamada, Y; Yamanoi, Y; Watanabe, H

2006-01-01

Nondestructive beam profile monitor utilizing ionizations of residual gas has been developed for continuous monitoring of 3?0(J-PARC). Knock-on electrons produced in the ionizations of residual gas vacuumed to 1 Pa are collected with a uniform electric field applied between electrodes. Applying a uniform electric field parallel to the electric field is essential to reduce diffusion of electrons crossing over magnetic flux. A prototype monitor has been constructed and installed in EP2-C beam line at KEK 12 GeV proton synchrotron (12 Ge V-PS). The profiles measured with the present monitor agree with the ones measured with the existing destructive profile monitor. The present monitor shows sufficient performances as a candidate of the profile monitor at J-PARC. In the present article, the working principle of the present monitor, the results of test experiments, and further developments are described in detail.

High power beam profile monitor with optical transition radiation

International Nuclear Information System (INIS)

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

1997-01-01

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 μm, 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/γ is originated from a region of transverse dimension roughly λγ; thus the apparent size of the source of transition radiation would become very large for highly relativistic particles. This monitor measures 100 μm beam sizes that are much smaller than the 3.2 mm λγ 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 μA of CW beam without causing noticeable beam loss, even at 800 MeV, the lowest CEBAF energy

Beam diagnostics for low energy beams

Directory of Open Access Journals (Sweden)

J. Harasimowicz

2012-12-01

Full Text Available Low-energetic ion and antimatter beams are very attractive for a number of fundamental studies. The diagnostics of such beams, however, is a challenge due to low currents down to only a few thousands of particles per second and significant fraction of energy loss in matter at keV beam energies. A modular set of particle detectors has been developed to suit the particular beam diagnostic needs of the ultralow-energy storage ring (USR at the future facility for low-energy antiproton and ion research, accommodating very low beam intensities at energies down to 20 keV. The detectors include beam-profile monitors based on scintillating screens and secondary electron emission, sensitive Faraday cups for absolute intensity measurements, and capacitive pickups for beam position monitoring. In this paper, the design of all detectors is presented in detail and results from beam measurements are shown. The resolution limits of all detectors are described and options for further improvement summarized. Whilst initially developed for the USR, the instrumentation described in this paper is also well suited for use in other low-intensity, low-energy accelerators, storage rings, and beam lines.

The Study of a Beam Profile Monitor based on Faraday Cup Array

Energy Technology Data Exchange (ETDEWEB)

Park, K. M.; Park, S. H.; Kim, S. G.; Kwon, H. J.; Cho, Y. S. [KAERI, Daejeon (Korea, Republic of)

2015-05-15

The metal can then be discharged to measure a small current equivalent to the number of impinging ions. The beam current can be measured and used to determine the number of ions or electrons hitting the cup. Recently, beam profile monitor (BPM) based on Faraday cup array (FCA), which represented beam position through the spatial and temporal distribution of the beam current, has been studied due to advantages of measure of wide-range ion beam current. FCA system is divided into a FC, an electrical circuit and display parts. We have studied FCA to monitor beam profile on an electrostatic accelerator with wide-range ion current. In this paper, we represented basic characteristics and designs for the fabricated FCA. FCA system, which consisted of FC system, electronic readout system, and output display, was suggested to measure ion beam current, efficiently. FC system consisted of a collimator, suppressor, tiny FC, insulator frame, and circuit board divided into elec PCB, cap PCB, and con PCB. FC size was 4 mm diameters and FCA system was considered as 8 x 8 array and whole size of 8 x 8 mm''2. FCA system was set-up in vacuum chamber and an integrator and output display parts were formed out of chamber to minimize number of feed-through.

Application of the inverse estimation method of current distribution from magnetic fields using genetic algorithm to beam profile measurement

International Nuclear Information System (INIS)

Kishimoto, M.; Sakasai, K.; Ara, K.

1994-01-01

In this paper, the new type of non-invasive beam profile monitor for intense ion accelerator using high-temperature superconductor. We regard the inverse estimation problem of beam profile as the optimum allocation problem of the currents into the cross-section of the beam vacuum pipe and applied genetic algorithm to solve this optimization problem. And we carried out the computer simulation to verify the effectiveness of this inverse estimation method of beam profile. (author)

High resolution, position sensitive detector for energetic particle beams

International Nuclear Information System (INIS)

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

1993-01-01

The performance and design of an imaging position sensitive, particle beam detector will be presented. The detector is minimally invasive, operates 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. 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. (orig.)

Effects of a laser beam profile on Zeeman electromagnetically induced transparency in the Rb buffer gas cell

International Nuclear Information System (INIS)

Nikolić, S N; Radonjić, M; Krmpot, A J; Lučić, N M; Zlatković, B V; Jelenković, B M

2013-01-01

Electromagnetically induced transparency (EIT) due to Zeeman coherences in the Rb buffer gas cell is studied for different laser beam profiles, laser beam radii and intensities from 0.1 to 10 mW cm −2 . EIT line shapes can be approximated by the Lorentzian for wide Gaussian laser beam (6.5 mm in diameter) if laser intensity is weak and for a Π laser beam profile of the same diameter. Line shapes of EIT become non-Lorentzian for the Gaussian laser beam if it is narrow (1.3 mm in diameter) or if it has a higher intensity. EIT amplitudes and linewidths, for both laser beam profiles of the same diameter, have very similar behaviour regarding laser intensity and Rb cell temperature. EIT amplitudes are maximal at a certain laser beam intensity and this intensity is higher for narrower laser beams. The EIT linewidth estimated at zero laser intensity is about 50 nT or 0.7 kHz, which refers to 1.5 ms relaxation times of Zeeman coherences in 87 Rb atoms in our buffer gas cell. Blocking of the centre of the wide Gaussian laser beam in front of the photo detector yields Lorentzian profiles with a much better contrast to the linewidth ratio for EIT at higher intensities, above ∼2 mW cm −2 . (paper)

Maximum entropy algorithm and its implementation for the neutral beam profile measurement

Energy Technology Data Exchange (ETDEWEB)

Lee, Seung Wook; Cho, Gyu Seong [Korea Advanced Institute of Science and Technology, Taejon (Korea, Republic of); Cho, Yong Sub [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

1998-12-31

A tomography algorithm to maximize the entropy of image using Lagrangian multiplier technique and conjugate gradient method has been designed for the measurement of 2D spatial distribution of intense neutral beams of KSTAR NBI (Korea Superconducting Tokamak Advanced Research Neutral Beam Injector), which is now being designed. A possible detection system was assumed and a numerical simulation has been implemented to test the reconstruction quality of given beam profiles. This algorithm has the good applicability for sparse projection data and thus, can be used for the neutral beam tomography. 8 refs., 3 figs. (Author)

Maximum entropy algorithm and its implementation for the neutral beam profile measurement

Energy Technology Data Exchange (ETDEWEB)

Lee, Seung Wook; Cho, Gyu Seong [Korea Advanced Institute of Science and Technology, Taejon (Korea, Republic of); Cho, Yong Sub [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

1997-12-31

A tomography algorithm to maximize the entropy of image using Lagrangian multiplier technique and conjugate gradient method has been designed for the measurement of 2D spatial distribution of intense neutral beams of KSTAR NBI (Korea Superconducting Tokamak Advanced Research Neutral Beam Injector), which is now being designed. A possible detection system was assumed and a numerical simulation has been implemented to test the reconstruction quality of given beam profiles. This algorithm has the good applicability for sparse projection data and thus, can be used for the neutral beam tomography. 8 refs., 3 figs. (Author)

High-resolution velocimetry in energetic tidal currents using a convergent-beam acoustic Doppler profiler

Science.gov (United States)

Sellar, Brian; Harding, Samuel; Richmond, Marshall

2015-08-01

An array of single-beam acoustic Doppler profilers has been developed for the high resolution measurement of three-dimensional tidal flow velocities and subsequently tested in an energetic tidal site. This configuration has been developed to increase spatial resolution of velocity measurements in comparison to conventional acoustic Doppler profilers (ADPs) which characteristically use divergent acoustic beams emanating from a single instrument. This is achieved using geometrically convergent acoustic beams creating a sample volume at the focal point of 0.03 m3. Away from the focal point, the array is also able to simultaneously reconstruct three-dimensional velocity components in a profile throughout the water column, and is referred to herein as a convergent-beam acoustic Doppler profiler (C-ADP). Mid-depth profiling is achieved through integration of the sensor platform with the operational commercial-scale Alstom 1 MW DeepGen-IV Tidal Turbine deployed at the European Marine Energy Center, Orkney Isles, UK. This proof-of-concept paper outlines the C-ADP system configuration and comparison to measurements provided by co-installed reference instrumentation. Comparison of C-ADP to standard divergent ADP (D-ADP) velocity measurements reveals a mean difference of 8 mm s-1, standard deviation of 18 mm s-1, and an order of magnitude reduction in realisable length scale. C-ADP focal point measurements compared to a proximal single-beam reference show peak cross-correlation coefficient of 0.96 over 4.0 s averaging period and a 47% reduction in Doppler noise. The dual functionality of the C-ADP as a profiling instrument with a high resolution focal point make this configuration a unique and valuable advancement in underwater velocimetry enabling improved quantification of flow turbulence. Since waves are simultaneously measured via profiled velocities, pressure measurements and surface detection, it is expected that derivatives of this system will be a powerful tool in

Monte Carlo investigation of the effect of small cutouts on beam profile parameters of 12 and 14 MeV electron beams

International Nuclear Information System (INIS)

Khaledi, Navid; Arbabi, Azim; Sardari, Dariush; Rabie Mahdavi, Seied; Aslian, Hossein; Dabaghi, Moloud; Sheibani, Kourosh

2013-01-01

Cutouts, which are used as field-shaping shield, affect several electron beam parameters. These effects are more observable for small field sizes and high energy electron beams. Owing to the fact that small fields prevent the lateral scatter equilibrium, at higher energies larger field radius is required for the establishment of lateral equilibrium. The profile curves are derived from circular, triangular, and square cutout shapes and size placed in a 10 × 10 cm 2 electron applicator. These profile curves are obtained using parallel plane type ion chamber at the R 100 , R 90 , R 80 and R 50 depths. Correspondingly, the source surface distance is 100 cm. In this study MCNP Monte Carlo (MC) simulation was used to compare Percentage Depth Dose (PDD) and Profile of electron beams. Monte Carlo and measured results showed a good compliance for PDD and beam profile. The measurements and calculations showed that as the field width decreases, the Flatness and Penumbra Ratio also decreases. In other words, flatter plateau was available for larger fields. Also the Coverage Ratio for each of the profiles is presented. The flatness and symmetry values for triangle shapes were greater than the two other shapes. Knowledge of these changes are significant in radiation therapy. Accordingly, a comparison between the Monte Carlo data and the measured results can be beneficial for treatment simulation and development of treatment planning systems. - Highlights: ► Mesh Tally 1 and pedep keyword were used to calculate the PDD and profile values. ► In measurement the coverage for larger fields and fewer doses are better. ► By increasing the depth, the flatness and symmetry values were increased. ► The worst flatness and symmetry (between 3 compared shapes) belonged to triangle. ► The given Penumbra and Coverage Ratio can be helpful for PTV margin and coverage

High resolution, position sensitive detector for energetic particle beams

Energy Technology Data Exchange (ETDEWEB)

Marsh, E P [Charles Evans and Associates, Redwood City, CA (United States); Strathman, M D [Charles Evans and Associates, Redwood City, CA (United States); Reed, D A [Charles Evans and Associates, Redwood City, CA (United States); Odom, R W [Charles Evans and Associates, Redwood City, CA (United States); Morse, D H [Sandia National Labs., Livermore, CA (United States); Pontau, A E [Sandia National Labs., Livermore, CA (United States)

1993-05-01

The performance and design of an imaging position sensitive, particle beam detector will be presented. The detector is minimally invasive, operates a wide dynamic range (>10[sup 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 [mu]m for a field of view of 1 mm has been reported. A higher resolution detector for imaging small beams (<50 [mu]m) with an image resolution of better than 0.5 [mu]m has since been developed and its design is presented. (orig.)

Development of a non-destructive beam-profile monitor based on scintillating fibre planes and SIPMs

CERN Document Server

AUTHOR|(INSPIRE)INSPIRE-00401943; Ferro-Luzzi, Massimiliano

CERN's Large Hadron Collider (LHC) is currently the largest particle accelerator in the world. To ensure particle energies at LHC's design values and enable collisions at high energies, the working settings and beam parameters are constantly monitored by the beam instrumentation division. The aim of this thesis is to present a new type of detector to monitor one such beam parameter, the transverse beam profile, and to present the results of an analysis of another beam attribute which reduces the luminosity of collider experiments. Part one of this thesis introduces a detector that uses beam-gas interactions to measure the transverse beam profile. The design of the detector is described in detail and the various components that ensure data quality are introduced. Tests that were conducted to investigate the performance of the detector, like timing and efficiency parameters, are presented as well. The first part is concluded with a summary of the work performed on the detector so far and an outlook of fut...

Dependence of neutron rate production with accelerator beam profile and energy range in an ADS-TRIGA RC1 reactor

Energy Technology Data Exchange (ETDEWEB)

Firoozabadi, M.M.; Karimi, J. [Birjand Univ. (Iran, Islamic Republic of). Dept. of Physics; Zangian, M. [Shahid Beheshti Univ., Tehran (Iran, Islamic Republic of). Nuclear Engineering Dept.

2016-12-15

Lead, mercury, tantalum and tungsten were used as target material for calculation of spallation processes in an ADS-TRIGA RC1 reactor. The results show that tungsten has the highest neutron production rate. Therefore it was selected as target material for further calculations. The sensitivity of neutron parameters of the ADS reactor core relative to a change of beam profile and proton energy was determined. The core assembly and parameters of the TRIGA RC1 demonstration facility were used for the calculation model. By changing the proton energy from 115 to 1 400 MeV by using the intra-nuclear cascade model of Bertini (INC-Bertini), the quantity of the relative difference in % for energy gain (G) and spallation neutron yield (Y{sub n/p}), increases to 289.99 % and 5199.15 % respectively. These changes also reduce the amount of relative difference for the proton beam current (I{sub p}) and accelerator power (P{sub acc}), 99.81 % and 81.28 % respectively. In addition, the use of a Gaussian distribution instead of a uniform distribution in the accelerator beam profile increases the quantity of relative difference for energy gain (G), net neutron multiplication (M) and spallation neutron yield (Y{sub n/p}), up to 4.93 %, 4.9 % and 5.55 % respectively.

Antibiotics sensitivity profile of proteus species associated with ...

African Journals Online (AJOL)

Antibiotics sensitivity profile of proteus species associated with specific infections at University of Ilorin Teaching Hospital, Ilorin. ... Results of the antimicrobial sensitivity testing showed that Imipenem and Piperacillin antibiotics were the most effective against Proteus sppwith each having 100%, followed by Ceftazidime ...

Axisymmetric instability of a self-pinched beam with rounded radial density profile

International Nuclear Information System (INIS)

Chen, H.C.; Uhm, H.S.

1983-01-01

The axisymmetric perturbations (sausage and hollowing modes) of an intense relativistic self-pinched electron beam propagating in a resistive plasma background are studied, especially for a beam with rounded radial density profile. The Bennett profiles are assumed for both the equilibrium beam current J/sub b/(r) = J/sub b/(0) (1+r 2 /R 2 /sub b/) -2 and plasma return current J/sub p/(r) = -fJ/sub b/(0) (1+r 2 /R 2 /sub p/) -2 , where R/sub b/ and R/sub p/ are the characteristic radii of the beam and plasma return currents, respectively. It is further assumed that the electric conductivity sigma(r) of the plasma channel is proportional to the return current. For a paraxial electron beam with complete space-charge neutralization by the ambient plasma, the axisymmetric modes can be destabilized by the phase lag between the magnetic field and beam current, even without the plasma return current. The plasma return current significantly modifies the growth rate of the instability such that the ratio of plasma current to beam current (-I/sub p//I/sub b/ = fR 2 /sub p// iR 2 /sub b/) largely determines the stability character of the beam. Furthermore, for the same fractional current neutralization f, the modes are highly unstable for a smaller ratio of plasma to beam radius R/sub p//R/sub b/. As compared to the resistive hose instability, the growth rates for the hollowing mode can be larger than those of the hose mode, while the sausage mode is much stabler than the hose mode. Stability properties are illustrated in detail for various system parameters

Gaussian beam profile shaping apparatus, method therefore and evaluation thereof

International Nuclear Information System (INIS)

Dickey, F.M.; Holswade, S.C.; Romero, L.A.

1999-01-01

A method and apparatus maps a Gaussian beam into a beam with a uniform irradiance profile by exploiting the Fourier transform properties of lenses. A phase element imparts a design phase onto an input beam and the output optical field from a lens is then the Fourier transform of the input beam and the phase function from the phase element. The phase element is selected in accordance with a dimensionless parameter which is dependent upon the radius of the incoming beam, the desired spot shape, the focal length of the lens and the wavelength of the input beam. This dimensionless parameter can also be used to evaluate the quality of a system. In order to control the radius of the incoming beam, optics such as a telescope can be employed. The size of the target spot and the focal length can be altered by exchanging the transform lens, but the dimensionless parameter will remain the same. The quality of the system, and hence the value of the dimensionless parameter, can be altered by exchanging the phase element. The dimensionless parameter provides design guidance, system evaluation, and indication as to how to improve a given system. 27 figs

Determination of boundaries between ranges of high and low gradient of beam profile.

Science.gov (United States)

Wendykier, Jacek; Bieniasiewicz, Marcin; Grządziel, Aleksandra; Jedynak, Tadeusz; Kośniewski, Wiktor; Reudelsdorf, Marta; Wendykier, Piotr

2016-01-01

This work addresses the problem of treatment planning system commissioning by introducing a new method of determination of boundaries between high and low gradient in beam profile. The commissioning of a treatment planning system is a very important task in the radiation therapy. One of the main goals of this task is to compare two field profiles: measured and calculated. Applying points of 80% and 120% of nominal field size can lead to the incorrect determination of boundaries, especially for small field sizes. The method that is based on the beam profile gradient allows for proper assignment of boundaries between high and low gradient regions even for small fields. TRS 430 recommendations for commissioning were used. The described method allows a separation between high and low gradient, because it directly uses the value of the gradient of a profile. For small fields, the boundaries determined by the new method allow a commissioning of a treatment planning system according to the TRS 430, while the point of 80% of nominal field size is already in the high gradient region. The method of determining the boundaries by using the beam profile gradient can be extremely helpful during the commissioning of the treatment planning system for Intensity Modulated Radiation Therapy or for other techniques which require very small field sizes.

Semi-empirical procedures for correcting detector size effect on clinical MV x-ray beam profiles

International Nuclear Information System (INIS)

Sahoo, Narayan; Kazi, Abdul M.; Hoffman, Mark

2008-01-01

The measured radiation beam profiles need to be corrected for the detector size effect to derive the real profiles. This paper describes two new semi-empirical procedures to determine the real profiles of high-energy x-ray beams by removing the detector size effect from the measured profiles. Measured profiles are corrected by shifting the position of each measurement point by a specific amount determined from available theoretical and experimental knowledge in the literature. The authors developed two procedures to determine the amount of shift. In the first procedure, which employs the published analytical deconvolution procedure of other investigators, the shift is determined from the comparison of the analytical fit of the measured profile and the corresponding analytical real profile derived from the deconvolution of the fitted measured profile and the Gaussian detector response function. In the second procedure, the amount of shift at any measurement point is considered to be proportional to the value of an analytical function related to the second derivative of the real profile at that point. The constant of proportionality and a parameter in the function are obtained from the values of the shifts at the 90%, 80%, 20%, and 10% dose levels, which are experimentally known from the published results of other investigators to be approximately equal to half of the radius of the detector. These procedures were tested by correcting the profiles of 6 and 18 MV x-ray beams measured by three different ionization chambers and a stereotactic field diode detector with 2.75, 2, 1, and 0.3 mm radii of their respective active cylindrical volumes. The corrected profiles measured by different detectors are found to be in close agreement. The detector size corrected penumbra widths also agree with the expected values based on the results of an earlier investigation. Thus, the authors concluded that the proposed procedures are accurate and can be used to derive the real

The low energy muon beam profile monitor for the muon g-2/EDM experiment at J-PARC

Science.gov (United States)

Razuvaev, G. P.; Bae, S.; Choi, H.; Choi, S.; Ko, H. S.; Kim, B.; Kitamura, R.; Mibe, T.; Otani, M.

2017-09-01

The muon g-2/EDM experiment at J-PARC aims to measure the muon anomalous magnetic moment and electric dipole moment with high precision by utilising an ultracold muon beam. The current muon g-2 discrepancy between the Standard Model prediction and the experimental value is about 3.5 standard deviations. This experiment requires a development of the muon LINAC to accelerate thermal muons to the 300 MeV/c momentum. Detectors for beam diagnostics play a key role in such an experiment. The beam profile monitoring system has been designed to measure the profile of the low energy muon beam. It was tested during two beam tests in 2016 at the MLF D2 line at J-PARC. The detector was used with positive muons, Mu-(μ+ e- e-), p and H-, e- and UV light. The system overview and preliminary results are given. Special attention is paid to the spatial resolution of the beam profile monitor and online monitor software used during data taking.

A self-calibrating ion beam profiler based on a CsI scintillator

Energy Technology Data Exchange (ETDEWEB)

Finocchiaro, P. E-mail: finocchiaro@lns.infn.it; Ciavola, G.; Cosentino, L.; Gu, M.; Raia, G.; Rovelli, A

1999-11-21

We report on the test results obtained with a prototype beam profiler based on a thin slit and a CsI scintillator, read out by means of a compact photomultiplier. Such a device has proven to be suitable to perform ion beam diagnostics at low and very low intensities. In particular, our device is suitable for being used in the energy and intensity ranges expected at the EXCYT radioactive ion beam facility, that is currently under development at LNS Catania.

A self-calibrating ion beam profiler based on a CsI scintillator

International Nuclear Information System (INIS)

Finocchiaro, P.; Ciavola, G.; Cosentino, L.; Gu, M.; Raia, G.; Rovelli, A.

1999-01-01

We report on the test results obtained with a prototype beam profiler based on a thin slit and a CsI scintillator, read out by means of a compact photomultiplier. Such a device has proven to be suitable to perform ion beam diagnostics at low and very low intensities. In particular, our device is suitable for being used in the energy and intensity ranges expected at the EXCYT radioactive ion beam facility, that is currently under development at LNS Catania

Fabrication of Faraday Cup Array for the Measurement of 2-Dimensional Proton Beam Profile

International Nuclear Information System (INIS)

Jung, Myunghwan; Kim, Bom Sok; Kim, Kyeryung

2014-01-01

It has an advantage of easy-to-use and possible to visually check, immediately; on the other hand, the measurement range is very limited. Another method is using the CCD camera-scintillator device such as p43 phosphor screen or chromox. A variety of faraday cup detectors have been recently introduced. The faraday cup is one of the powerful and popular tools for the measurement of beam current. By using several faraday cups in array geometry, it is possible to observe current distribution. In this study, we developed an external faraday cup array for the measure the beam current and profile at a KOMAC (Korea Multi-purpose Accelerator Complex) beam utilization facility. To measure the beam profile, before fabrication of faraday cup array, we use gafchromic film. By making the faraday cup array we were able to reduce the consumption of Gafchromic film and a more accurate diagnosis of the proton beam is possible. The use of faraday cup array, experiment using the proton beam is more reliable and confident

Spectrally resolved measurements of the terahertz beam profile generated from a two-color air plasma

DEFF Research Database (Denmark)

Pedersen, Pernille Klarskov; Zalkovskij, Maksim; Strikwerda, Andrew

2014-01-01

Using a THz camera and THz bandpass filters, we measure the frequency - resolved beam profile emitted from a two - color air plasma. We observe a frequency - independent emission angle from the plasma .......Using a THz camera and THz bandpass filters, we measure the frequency - resolved beam profile emitted from a two - color air plasma. We observe a frequency - independent emission angle from the plasma ....

Ion temperature profiles along a hydrogen diagnostic beam in a TORE SUPRA tokamak plasma

International Nuclear Information System (INIS)

Romannikov, A.; Petrov, Yu.; Platts, P.; Khess, V.; Khutter, T.; Farzhon, Zh.; Moro, F.

2002-01-01

By means of corpuscular diagnostics one studies temperature of ions along a diagnostic hydrogen beam. Paper presents comparison of temperature of plasma (deuterium) basic ions measures by means of the active corpuscular diagnostics with temperature of C + carbon ions along a beam. One studies behavior peculiarities of T i ion temperature profiles for TORE-SUPRA different modes, such as: formation of plane and even hollow T i profiles for ohmic modes, variation of T i profiles under operation of an ergodic diverter, difference of temperature of basic ions measured by means of the active corpuscular diagnostics from C +5 temperature. Paper offers clear explanation of these peculiarities [ru

Calculation of microplanar beam dose profiles in a tissue/lung/tissue phantom

International Nuclear Information System (INIS)

Company, F.Z.; Allen, B.J.

1998-01-01

Recent advances in synchrotron generated x-ray beams with a high fluence rate permit investigation of the application of an array of closely spaced, parallel or converging microplanar beams in radiotherapy. The proposed technique takes advantage of the hypothesized repair mechanism of capillary cells between alternate microbeam zones, which regenerates the lethally irradiated endothelial cells. The lateral and depth doses of 100 keV microplanar beams are investigated for different beam dimensions and spacings in a tissue, lung and tissue/lung/tissue phantom. The EGS4 Monte Carlo code is used to calculate dose profiles at different depths and bundles of beams (up to 20x20cm square cross section). The maximum dose on the beam axis (peak) and the minimum interbeam dose (valley) are compared at different depths, bundles, heights, widths and beam spacings. (author)

Gene-expression profiling after exposure to C-ion beams

International Nuclear Information System (INIS)

Saegusa, Kumiko; Furuno, Aki; Ishikawa, Kenichi; Ishikawa, Atsuko; Ohtsuka, Yoshimi; Kawai, Seiko; Imai, Takashi; Nojima, Kumie

2005-01-01

It is recognized that carbon-ion beam kills cancer cells more efficiently than X-ray. In this study we have compared cellular gene expression response after carbon-ion beam exposure with that after X-ray exposure. Gene expression profiles of cultured neonatal human dermal fibroblasts (NHDF) at 0, 1, 3, 6, 12, 18, and 24 hr after exposure to 0.1, 2 and 5 Gy of X-ray or carbon-ion beam were obtained using 22K oligonucleotide microarray. N-way ANOVA analysis of whole gene expression data sets selected 960 genes for carbon-ion beam and 977 genes for X-ray, respectively. Interestingly, majority of these genes (91% for carbon-ion beam and 88% for X-ray, respectively) were down regulated. The selected genes were further classified by their dose-dependence or time-dependence of gene expression change (fold change>1.5). It was revealed that genes involved in cell proliferation had tendency to show time-dependent up regulation by carbon-ion beam. Another N-way ANOVA analysis was performed to select 510 genes, and further selection was made to find 70 genes that showed radiation species-dependent gene expression change (fold change>1.25). These genes were then categorized by the K-Mean clustering method into 4 clusters. Each cluster showed tendency to contain genes involved in cell cycle regulation, cell death, responses to stress and metabolisms, respectively. (author)

OTR profile measurement of a LINAC electron beam with portable ultra high-speed camera

International Nuclear Information System (INIS)

Mogi, T.; Nisiyama, S.; Tomioka, S.; Enoto, T.

2004-01-01

We have studied on and developed a portable ultra high-speed camera, and so applied to measurement of a LINAC electron beam. We measured spatial OTR profiles of a LINAC electron beam using this camera with temporal resolution 80ns. (author)

Turn-by-Turn Imaging of the Transverse Beam Profile in PEP-II

Energy Technology Data Exchange (ETDEWEB)

Fisher, Alan A.; Petree, Mark; /SLAC

2006-12-18

During injection or instability, the transverse profile of an individual bunch in a storage ring can change significantly in a few turns. However, most synchrotron-light imaging techniques are not designed for this time scale. We have developed a novel diagnostic that enhances the utility of a fast gated camera by adding, inexpensively, some features of a dual-axis streak camera, in order to watch the turn-by-turn evolution of the transverse profile, in both x and y. The beam's elliptical profile is reshaped using cylindrical lenses to form a tall and narrow ellipse--essentially the projection of the full ellipse onto one transverse axis. We do this projection twice, by splitting the beam into two paths at different heights, and rotating the ellipse by 90{sup o} on one path. A rapidly rotating mirror scans these vertical ''pencils'' of light horizontally across the photocathode of the camera, which is gated for 3 ns on every Nth ring turn. A single readout of the camera captures 100 images, looking like a stroboscopic photograph of a moving object. We have observed the capture of injected charge into a bunch and the rapid change of beam size at the onset of a fast instability.

Three-beam aerosol backscatter correlation lidar for wind profiling

Science.gov (United States)

Prasad, Narasimha S.; Radhakrishnan Mylapore, Anand

2017-03-01

The development of a three-beam aerosol backscatter correlation (ABC) light detection and ranging (lidar) to measure wind characteristics for wake vortex and plume tracking applications is discussed. This is a direct detection elastic lidar that uses three laser transceivers, operating at 1030-nm wavelength with ˜10-kHz pulse repetition frequency and nanosec class pulse widths, to directly obtain three components of wind velocities. By tracking the motion of aerosol structures along and between three near-parallel laser beams, three-component wind speed profiles along the field-of-view of laser beams are obtained. With three 8-in. transceiver modules, placed in a near-parallel configuration on a two-axis pan-tilt scanner, the lidar measures wind speeds up to 2 km away. Optical flow algorithms have been adapted to obtain the movement of aerosol structures between the beams. Aerosol density fluctuations are cross-correlated between successive scans to obtain the displacements of the aerosol features along the three axes. Using the range resolved elastic backscatter data from each laser beam, which is scanned over the volume of interest, a three-dimensional map of aerosol density can be generated in a short time span. The performance of the ABC wind lidar prototype, validated using sonic anemometer measurements, is discussed.

Measurement of the density profile of pure and seeded molecular beams by femtosecond ion imaging

Energy Technology Data Exchange (ETDEWEB)

Meng, Congsen [LaserLaB Amsterdam, VU University Amsterdam, de Boelelaan 1083, 1081 HV Amsterdam (Netherlands); Department of Physics, National University of Defense Technology, Changsha 410073 (China); Janssen, Maurice H. M. [LaserLaB Amsterdam, VU University Amsterdam, de Boelelaan 1083, 1081 HV Amsterdam (Netherlands)

2015-02-15

Here, we report on femtosecond ion imaging experiments to measure the density profile of a pulsed supersonic molecular beam. Ion images are measured for both a molecular beam and bulk gas under identical experimental conditions via femtosecond multiphoton ionization of Xe atoms. We report the density profile of the molecular beam, and the measured absolute density is compared with theoretical calculations of the centre line beam density. Subsequently, we discuss reasons accounting for the differences between measurements and calculations and propose that strong skimmer interference is the most probable cause for the differences. Furthermore, we report on experiments measuring the centre line density of seeded supersonic beams. The femtosecond ion images show that seeding the heavy Xe atom at low relative seed fractions (1%-10%) in a light carrier gas like Ne results in strong relative enhancements of up to two orders of magnitude.

Electron temperature profiles in high power neutral-beam-heated TFTR [Tokamak Fusion Test Reactor] plasmas

International Nuclear Information System (INIS)

Taylor, G.; Grek, B.; Stauffer, F.J.; Goldston, R.J.; Fredrickson, E.D.; Wieland, R.M.; Zarnstorff, M.C.

1987-09-01

In 1986, the maximum neutral beam injection (NBI) power in the Tokamak Fusion Test Reactor (TFTR) was increased to 20 MW, with three beams co-parallel and one counter-parallel to I/sub p/. TFTR was operated over a wide range of plasma parameters; 2.5 19 19 m -3 . Data bases have been constructed with over 600 measured electron temperature profiles from multipoint TV Thomson scattering which span much of this parameter space. We have also examined electron temperature profile shapes from electron cyclotron emission at the fundamental ordinary mode and second harmonic extraordinary mode for a subset of these discharges. In the light of recent work on ''profile consistency'' we have analyzed these temperature profiles in the range 0.3 < (r/a) < 0.9 to determine if a profile shape exists which is insensitive to q/sub cyl/ and beam-heating profile. Data from both sides of the temperature profile [T/sub e/(R)] were mapped to magnetic flux surfaces [T/sub e/(r/a)]. Although T/sub e/(r/a), in the region where 0.3 < r/a < 0.9 was found to be slightly broader at lower q/sub cyl/, it was found to be remarkably insensitive to β/sub p/, to the fraction of NBI power injected co-parallel to I/sub p/, and to the heating profile going from peaked on axis, to hollow. 10 refs., 8 figs

Technique using axicons for generating flat-top laser-beam profiles

International Nuclear Information System (INIS)

Viswanathan, V.K.; Woodfin, G.L.; Stahl, D.; Carpenter, J.P.; Kyrala, G.

1983-01-01

In certain fusion experiments using CO 2 lasers, like Helios, it is desired to produce a focal spot several times larger than the nominal focal spot, with a flat beam profile. The typical focal spot in Helios is roughly 70 μm and just defocussing the beam produces beam breakup, with several hot spots with roughly the original diameter, and a gaussian distribution. A number of schemes were tried to achieve a large spot with desired characteristics. These are described in the article. Axicons were found to produce spots with desired characteristics. Axicons are lenses or mirrors having a cone-shaped surface. The various schemes are described, as well as an experiment in Helios which confirmed that axicons produced the spots with desirable characteristics. Helios is an 8-beam CO 2 laser which produces 10 kJ at power in excess of 20 TW. It is currently being used for Laser Fusion studies at the Los Alamos National Laboratory

Construction of a high resolution electron beam profile monitor

International Nuclear Information System (INIS)

Norem, J.; Dawson, J.; Haberichter, W.; Novak, W.; Reed, L.; Yang, X.F.

1993-01-01

Bremsstrahlung from an electron beam on a heavy target can be used to image the beam profile using collimators and slits. The limiting resolution using this system is determined by Fresnel diffraction, and is ∼ √(λd/2), where λ is the photon wavelength and d is determined by the linear dimensions of the system. For linear colliders this resolution could be a few nm. The highest resolution requires detectors which see only high energy, (small λ), photons, and this is accomplished by converting photons to pairs, and detecting Cherenkov light in a nearly forward angle with a CCD detector or streak camera. Tests are planned at the Argonne APS and SLAC FFTB

A high repetition rate transverse beam profile diagnostic for laser-plasma proton sources

Science.gov (United States)

Dover, Nicholas; Nishiuchi, Mamiko; Sakaki, Hironao; Kando, Masaki; Nishitani, Keita

2016-10-01

The recently upgraded J-KAREN-P laser can provide PW peak power and intensities approaching 1022 Wcm-2 at 0.1 Hz. Scaling of sheath acceleration to such high intensities predicts generation of protons to near 100 MeV, but changes in electron heating mechanisms may affect the emitted proton beam properties, such as divergence and pointing. High repetition rate simultaneous measurement of the transverse proton distribution and energy spectrum are therefore key to understanding and optimising the source. Recently plastic scintillators have been used to measure online proton beam transverse profiles, removing the need for time consuming post-processing. We are therefore developing a scintillator based transverse proton beam profile diagnostic for use in ion acceleration experiments using the J-KAREN-P laser. Differential filtering provides a coarse energy spectrum measurement, and time-gating allows differentiation of protons from other radiation. We will discuss the design and implementation of the diagnostic, as well as proof-of-principle results from initial experiments on the J-KAREN-P system demonstrating the measurement of sheath accelerated proton beams up to 20 MeV.

Role of beam orientation optimization in intensity-modulated radiation therapy

International Nuclear Information System (INIS)

Pugachev, Andrei; Li, Jonathan G.; Boyer, Arthur L.; Hancock, Steven L.; Le, Quynh-Thu; Donaldson, Sarah S.; Lei Xing

2001-01-01

Purpose: To investigate the role of beam orientation optimization in intensity-modulated radiation therapy (IMRT) and to examine the potential benefits of noncoplanar intensity-modulated beams. Methods and Materials: A beam orientation optimization algorithm was implemented. For this purpose, system variables were divided into two groups: beam position (gantry and table angles) and beam profile (beamlet weights). Simulated annealing was used for beam orientation optimization and the simultaneous iterative inverse treatment planning algorithm (SIITP) for beam intensity profile optimization. Three clinical cases were studied: a localized prostate cancer, a nasopharyngeal cancer, and a paraspinal tumor. Nine fields were used for all treatments. For each case, 3 types of treatment plan optimization were performed: (1) beam intensity profiles were optimized for 9 equiangular spaced coplanar beams; (2) orientations and intensity profiles were optimized for 9 coplanar beams; (3) orientations and intensity profiles were optimized for 9 noncoplanar beams. Results: For the localized prostate case, all 3 types of optimization described above resulted in dose distributions of a similar quality. For the nasopharynx case, optimized noncoplanar beams provided a significant gain in the gross tumor volume coverage. For the paraspinal case, orientation optimization using noncoplanar beams resulted in better kidney sparing and improved gross tumor volume coverage. Conclusion: The sensitivity of an IMRT treatment plan with respect to the selection of beam orientations varies from site to site. For some cases, the choice of beam orientations is important even when the number of beams is as large as 9. Noncoplanar beams provide an additional degree of freedom for IMRT treatment optimization and may allow for notable improvement in the quality of some complicated plans

Improved support films for electron microscopy of beam sensitive specimens

International Nuclear Information System (INIS)

Taylor, J.R.; Glaeser, R.M.

1987-01-01

Preliminary results indicate that technical innovations can address the problem of beam-induced movement and provide improved prospects for high resolution imaging of beam-sensitive specimens. Second-generation experiments with microgrid supports are in progress with efforts focusing on the objectives of maximizing the contact between the carbon film and its microgrid support and on improving the flatness of microgrids. When more robust support films are available they will be used in conjunction with small spot illumination. 4 refs., 2 figs

Beam profile measurements on the advanced test accelerator using optical techniques

International Nuclear Information System (INIS)

Chong, Y.P.; Kalibjian, R.; Cornish, J.P.; Kallman, J.S.; Donnelly, D.

1986-01-01

Beam current density profiles of ATA have been measured both spatially and temporally using a number of diagnostics. An extremely important technique involves measuring optical emissions from either a target foil inserted into the beam path or gas atoms and molecules excited by beam electrons. This paper describes the detection of the optical emission. A 2-D gated television camera with a single or dual micro-channel-plate (MCP) detector for high gain provides excellent spatial and temporal resolution. Measurements are routinely made with resolutions of 1 mm and 5 ns respectively. The optical line of sight allows splitting part of the signal to a streak camera or photometer for even higher time resolution

Site-selective dopant profiling of p-n junction specimens in the dual-beam FIB/SEM system

International Nuclear Information System (INIS)

Chee, K W A; Beanland, R; Midgley, P A; Humphreys, C J

2010-01-01

Results from site-specific dopant profiling in a dual-beam FIB/SEM system are reported. Si specimens containing p-n junctions were milled using Ga + ion beam energies ranging from 30 keV to 2 keV, and analysed in situin the vacuum chamber. We compare the dopant contrast observed when milling a cleaved surface to that obtained from a side-wall of a trench cut using 30 kV Ga + ions, and using successively lower ion beam energies. The latter technique is suitable for site-specific dopant profiling. We find that lower energy ion beam milling significantly improves contrast, but only achieves 50 % of that observed on a freshly-cleaved surface. Furthermore, the contrast on a side-wall previously milled using high energy Ga + ions is less than that of a cleaved surface subjected to the same ion beam energy.

Beam diagnostic instruments of TARN

International Nuclear Information System (INIS)

Watanabe, Shin-ichi.

1987-09-01

The paper summarizes the beam diagnostic instruments of the low energy ion accumulation ring; TARN. With these monitors, position, profiles, bunch structure, intensity, emittance and momentum spread were measured to evaluate the injection and stacking experiments. The monitors provide the sensitivity of a few μA for the nondestructive and a few nA for the destructive monitors. Discussions on monitor probe and electronics are presented on the basis of an achievement of the beam stacking experiments. (author)

Wide dynamic range beam profile monitor

International Nuclear Information System (INIS)

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

INFLUENCE OF LASER BEAM PROFILE ON LIGHT SCATTERING BY HUMAN SKIN DURING PHOTOMETRY BY ELLIPSOIDAL REFLECTORS

Directory of Open Access Journals (Sweden)

M. A. Bezuglyi

2018-01-01

Full Text Available The correct accounting of laser emitter parameters for improvement of diagnostic authenticity of methods of optical biomedical diagnostic is important problem for applied biophotonic tasks. The purpose of the current research is estimation of influence of energy distribution profile in transversal section of laser beam on light scattering by human skin layers at photometry by ellipsoidal reflectors.Biomedical photometer with ellipsoidal reflectors for investigation of biological tissue specimens in transmitted and reflected light uses laser probing radiation with infinitely thin, Gauss-type and uniform cross-section profile. Distribution of beams with denoted profiles, which consist of 20 million photons with wavelength 632.8 nm, was modeled by using of Monte-Carlo simulation in human skin layers (corneous layer, epidermis, derma and adipose tissue of various anatomic thickness and with ellipsoidal reflectors with focal parameter equal to 16.875 mm and eccentricity of 0.66.The modeling results represent that illuminance distribution in zones of photometric imaging is significantly influenced by the laser beam cross-section profile for various thickness of corneous layer and epidermis in transmitted and reflected light, and also derma in reflected light. Illuminance distribution for adipose tissue in reflected and transmitted light, and also derma in transmitted light, practically do not depend of laser beam profile for anatomic thicknesses, which are appropriate for human skin on various sections of body.There are represented results of modified Monte-Carlo simulation method for biomedical photometer with ellipsoidal reflectors during biometry of human skin layers. For highly scattered corneous layer and epidermis the illumination of middle and external rings of photometric images changes depending from the laser beam profile for more than 50 % in transmitted and 30 % in reflected light. For weakly scattering skin layers (derma and adipose layer

Control of the ultrasonic beam transmitted through an irregular profile using a smart flexible transducer: modelling an application

Energy Technology Data Exchange (ETDEWEB)

Roy, O.; Mahaut, S.; Casula, O. [CEA Fontenay aux Roses, DRT/LIST/DECS/STA/LMUS, 92 (France)

2001-07-01

In most of industries as aeronautics, aerospace and nuclear, the main part of the ultrasonic testing is carried out directly in touch with the inspected component. Among others, the cooling piping of French pressurized water reactor comprises many welding components with complex geometry: elbows, butt welds, nozzles. In service inspections of such components performed with conventional ultrasonic contact transducers present limited performances. Variations in sensitivity are produced by unmatched contact on irregular surface, which results in poor detection performances. In addition, the beam orientation transmitted through complex interfaces cannot be totally controlled, because of the disorientations suffered by the transducer during its displacement. As a result, a possible defect cannot be correctly detected, positioned and characterized. At last, the geometry of some components limits the displacement of the transducer, resulting in an uncovered scan area. To overcome these difficulties and to improve the performances of such inspections, the CEA, supported by the safety authorities (IPSN), has developed a new concept of phased array. Recent studies have been made to obtain further performances improvements of this system, including instrumentation development and a new phased array design. Inspections have been performed on a specimen containing artificial defects under a realistic profile, with an adaptive mode to compensate the effect of the irregular profile. Experimental results, displayed using specific imaging, show the ability of this system to detect and characterize defects under irregular profiles, using longitudinal or shear waves in a fully mastered beam. (authors)

A LVDT conditioner for the beam profile monitors of the AmPS

International Nuclear Information System (INIS)

Es, J.T. van; Trigt, J.H. van.

1991-01-01

A LVDT (Linear Variable Differential Transformer) is a transducer for localization. Because of its applied materials, its construction and the absence of bearings etc. the instrument is suitable to be applied in locations where radioactive radiation is present. In order to obtain information about the position of the iron core in the transducer, a conditioner is needed. In 1977 by Digel a conditioner has been developed for the beam profile monitors (moving wire) of MEA because the 'market' could not meet the requirements then. Nowadays the 'market' offers i.c.'s which can take over the work of the Eurocard developed then. Digel has investigated them in order to see if they are applicable for the beam profile monitors of AmPS. (author). 5 refs.; 7 figs.; 13 tabs

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

CERN Document Server

CERN. Geneva

2014-01-01

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

SU-E-T-149: Electron Beam Profile Differences Between Elekta MLCi2 and Elekta Agility Treatment Heads

Energy Technology Data Exchange (ETDEWEB)

Wu, C [Sutter Medical Foundation, Roseville, CA 95661 (United States); Hatcher, C [Sutter Shared Services S3, Sacramento, CA (United States)

2014-06-01

Purpose: To report and investigate observed differences in electron beam profiles at various energies/applicators between Elekta MLCi2 and Agility treatment head on Elekta Infinity LINAC Methods: When we upgraded from MLCi2 to Agility on one of our Elekta Infinity LINAC's, electron beam PDDs and profiles were acquired for comparison purpose. All clinical electron energies (6/9/12/15/12/18 MeV) and electron applicators (6/10/14/20/25 square) were included in measurement. PDDs were acquired at 100 SSD in water (PTW MP3 water tank) with a plane-parallel ion chamber (PTW Roos). X and Y Profiles were acquired using IC Profiler (Sun Nuclear Corp.) at 1cm and maximum PDD depths (water equivalent). Results: All PDD curves match very well between MLCi2 and Agility treatment head. However, some significant differences on electron profiles were found. On Agility, even after increasing the default auto-tracking offset values for backup diaphragms in Y and MLC in X by 2.8 cm (the maximum allowed change is 3.0 cm), electron profiles still have rounder shoulders comparing to corresponding MLCi2 profiles. This difference is significantly more pronounced at larger applicators (20 and 25 square), for all electron energies. Conclusion: The significant design change between MLCi2 and Agility beam limiting device seems to affect exit electron beam profiles. In IEC1217 X direction, the main change on Agility is the removal of the original MLCi2 X backup diaphragms and replacing it with MLC leaves; In Y direction, the main change is the radius and materials on Y backup diaphragms.

Measurements of laser-imprinting sensitivity to relative beam mistiming in planar plastic foils driven by multiple overlapping laser beams

International Nuclear Information System (INIS)

Smalyuk, V.A.; Goncharov, V.N.; Boehly, T.R.; Delettrez, J.A.; Li, D.Y.; Marozas, J.A.; Maximov, A.V.; Meyerhofer, D.D.; Regan, S.P.; Sangster, T.C.

2005-01-01

In a direct-drive, inertial confinement fusion implosion, a spherical target is irradiated by a large number of overlapped laser beams. Imprinting of laser modulations depends on the relative arrival time of laser beams and their angles of incidence. This dependence was measured in planar plastic targets using six overlapping beams on the OMEGA laser system [T. R. Boehly, D. L. Brown, R. S. Craxton, R. L. Keck, J. P. Knauer, J. H. Kelly, T. J. Kessler, S. A. Kumpan, S. J. Loucks, S. A. Letzring, F. J. Marshall, R. L. McCrory, S. F. B. Morse, W. Seka, J. M. Soures, and C. P. Verdon, Opt. Commun. 133, 495 (1997)]. One of the beams (the imprint beam) had a special phase plate that produced two-dimensional modulations on the target, easily distinguishable from the features imprinted by the other five drive beams. The timing of the imprint beam was varied with respect to the drive beams to study imprinting sensitivity to beam mistiming. Shifting the imprint beam to arrive before the other beams significantly increased the imprint efficiency. The results are in very good agreement with the model predictions

Investigation of the depth profile of ion beam induced nanopatterns on Si with simultaneous metal incorporation

Energy Technology Data Exchange (ETDEWEB)

Khanbabaee, Behnam; Arezki, Bahia; Biermanns, Andreas; Pietsch, Ullrich [Festkoerperphysik, Universitaet Siegen, Siegen (Germany); Cornejo, Marina; Frost, Frank [Leibniz-Institut fuer Oberflaechenmodifizierung (IOM), Leipzig (Germany)

2011-07-01

Ion beam sputtering of semiconductor surfaces can modify the surface and produce a diversity of surface topographies such as periodic ripples or dot structures depended on sputtering parameters. Well ordered nanostructured surfaces have widely technological applications. Recent experiments have shown that the incorporation of metallic impurity atoms during the sputtering process plays a crucial role in pattern formation on the surfaces. These findings offer a new degree of freedom to control pattern formation. In this contribution we report on surface patterning due to Kr ion beam erosion on silicon surfaces with simultaneous Fe and Cr incorporation. We used X-ray reflectivity (XRR) to determine the depth profiles of metal ions as function of ion beam divergence angles and the mean incidence angle of the ions with respect to the surface normal. Depth profiles are correlated with degree of pattern formation determined by AFM. We show that the mean penetration depth and concentration of metal ions depends on the divergence angle of Kr beam provided by Kaufman source which supports the assumption that metal ions are created due to parasitic interaction of the Kr beam with the steel plate lining. The evaluated depth profile by XRR is in good agreement with SIMS and RBS results.

Measurement of the density profile of pure and seeded molecular beams by femtosecond ion imaging

NARCIS (Netherlands)

Meng, C.; Janssen, M.H.M.

2015-01-01

Here, we report on femtosecond ion imaging experiments to measure the density profile of a pulsed supersonic molecular beam. Ion images are measured for both a molecular beam and bulk gas under identical experimental conditions via femtosecond multiphoton ionization of Xe atoms. We report the

If Frisch is true - impacts of varying beam width, resolution, frequency combinations and beam overlap when retrieving liquid water content profiles

Science.gov (United States)

Küchler, N.; Kneifel, S.; Kollias, P.; Loehnert, U.

2017-12-01

Cumulus and stratocumulus clouds strongly affect the Earth's radiation budget and are a major uncertainty source in weather and climate prediction models. To improve and evaluate models, a comprehensive understanding of cloud processes is necessary and references are needed. Therefore active and passive microwave remote sensing of clouds can be used to derive cloud properties such as liquid water path and liquid water content (LWC), which can serve as a reference for model evaluation. However, both the measurements and the assumptions when retrieving physical quantities from the measurements involve uncertainty sources. Frisch et al. (1998) combined radar and radiometer observations to derive LWC profiles. Assuming their assumptions are correct, there will be still uncertainties regarding the measurement setup. We investigate how varying beam width, temporal and vertical resolutions, frequency combinations, and beam overlap of and between the two instruments influence the retrieval of LWC profiles. Especially, we discuss the benefit of combining vertically, high resolved radar and radiometer measurements using the same antenna, i.e. having ideal beam overlap. Frisch, A. S., G. Feingold, C. W. Fairall, T. Uttal, and J. B. Snider, 1998: On cloud radar and microwave radiometer measurements of stratus cloud liquid water profiles. J. Geophys. Res.: Atmos., 103 (18), 23 195-23 197, doi:0148-0227/98/98JD-01827509.00.

Relativistic self-focusing of intense laser beam in thermal collisionless quantum plasma with ramped density profile

Directory of Open Access Journals (Sweden)

S. Zare

2015-04-01

Full Text Available Propagation of a Gaussian x-ray laser beam has been analyzed in collisionless thermal quantum plasma with considering a ramped density profile. In this density profile due to the increase in the plasma density, an earlier and stronger self-focusing effect is noticed where the beam width oscillates with higher frequency and less amplitude. Moreover, the effect of the density profile slope and the initial plasma density on the laser propagation has been studied. It is found that, by increasing the initial density and the ramp slope, the laser beam focuses faster with less oscillation amplitude, smaller laser spot size and more oscillations. Furthermore, a comparison is made among the laser self-focusing in thermal quantum plasma, cold quantum plasma and classical plasma. It is realized that the laser self-focusing in the quantum plasma becomes stronger in comparison with the classical regime.

Beam profile diagnostics system for SDUV-FEL

International Nuclear Information System (INIS)

Xu Yichao; Han Lifeng; Chen Yongzhong

2010-01-01

A new beam profile diagnostics system for Shanghai Deep Ultraviolet Free Electron Laser (SDUV-FEL) has been developed based on industrial Ethernet, with good versatility and scalability. The system includes three major subsystems for image acquisition,pneumatic control and stepper motor control, respectively. Virtual instrument technology is adopted to drive the devices, and to develop the measurement software. In this paper,we describe the system structure, and its hardware and software design. The results of system commissioning are given as well. As an important diagnostic tool and data acquisition method, the system has been successfully applied to the measurement and control of the SDUV-FEL.(authors)

Two-dimensional beam-profile monitor using the Reticon MC510A array camera

International Nuclear Information System (INIS)

Gottschalk, B.

1981-08-01

A quantitative two-dimensional beam profile may be obtained from a scintillator viewed by a Reticon camera which uses a 32 x 32 array of photodiodes as its sensing element. In this note, CAMAC-oriented data acquisition electronics which allow one either to transmit the profile to a computer, or to use the monitor in a stand-alone mode are described

SYSTEMATIC ERROR REDUCTION: NON-TILTED REFERENCE BEAM METHOD FOR LONG TRACE PROFILER

International Nuclear Information System (INIS)

QIAN, S.; QIAN, K.; HONG, Y.; SENG, L.; HO, T.; TAKACS, P.

2007-01-01

Systematic error in the Long Trace Profiler (LTP) has become the major error source as measurement accuracy enters the nanoradian and nanometer regime. Great efforts have been made to reduce the systematic error at a number of synchrotron radiation laboratories around the world. Generally, the LTP reference beam has to be tilted away from the optical axis in order to avoid fringe overlap between the sample and reference beams. However, a tilted reference beam will result in considerable systematic error due to optical system imperfections, which is difficult to correct. Six methods of implementing a non-tilted reference beam in the LTP are introduced: (1) application of an external precision angle device to measure and remove slide pitch error without a reference beam, (2) independent slide pitch test by use of not tilted reference beam, (3) non-tilted reference test combined with tilted sample, (4) penta-prism scanning mode without a reference beam correction, (5) non-tilted reference using a second optical head, and (6) alternate switching of data acquisition between the sample and reference beams. With a non-tilted reference method, the measurement accuracy can be improved significantly. Some measurement results are presented. Systematic error in the sample beam arm is not addressed in this paper and should be treated separately

Minimal interference beam size/profile measurement techniques applicable to the Collider

International Nuclear Information System (INIS)

Nexsen, W.; Dutt, S.; Kauffmann, S.; Lebedev, V.; Maschke, A.; Mokhov, N.; Richardson, R.; Tsyganov, E.; Zinchenko, A.

1993-05-01

The imaging of synchrotron radiation (SR) has been suggested as a technique for providing a continuous, non-interfering monitor of the beam profile in the Collider rings at the Superconducting Super Collider. A closer examination has raised questions concerning the applicability of SR imaging in this case because of the diffraction broadening of the image, the requirements for axial space and location in the lattice, and the complexity of the system. We have surveyed the known, alternative, minimal interference techniques for measuring beam size and have evaluated them for possible Collider usage. We conclude that of the approaches that appear feasible, all require at least some development for our usage and that the development of an electron beam probe offers the best promise. We recommend that flying wires be used for cross-checking and calibrating the electron beam probe diagnostic and for luminosity measurements when the highest accuracy is required, but flying wires should not be used as the primary diagnostic because of their limited lifetime

Sensitivity of the PEP beam transport line to perturbations

International Nuclear Information System (INIS)

Peterson, J.M.; Brown, K.L.

1979-03-01

The sensitivity of a beam-transport line to various perturbations determines the extent to which one can simplify component design and relax tolerances. For the PEP injection lines, effects of various fabrication errors, magnet misalignments, and residual gas scattering were studied. Using the TURTLE ray-tracing program, it is found that magnetic-field errors corresponding to a relative sextupole strength in the dipoles of 0.5% and/or a relative sextupole or octupole strength in the quadrupoles of 5% are permissible. This allows relatively loose tolerances in magnet fabrication. Transverse misalignment of a quadrupole by a distance x causes the beam centroid to be displaced downstream by as much as 5x. This requires a quadrupole alignment accuracy of +- 0.5 mm or better. No compensation for the earth's field is necessary because an integral number of optical wavelengths and a short wavelength were used for the design. Analysis shows that beam broadening from multiple coulomb scattering is insignificant for pressures of less than 1/10 torr

A beam-profile monitor for the BNL Accelerator Test Facility (ATF)

International Nuclear Information System (INIS)

Russell, D.P.; McDonald, K.T.

1989-01-01

A beam-profile monitor has been designed to diagnose the 5-MeV high-brightness electron beam from the rf gun of the BNL Accelerator Test Facility (ATF). The monitor consists of a phosphor screen viewed by a CCD camera. The video images are digitized and stored by a framegrabber and analyzed by an IBM PC-AT to extract the emittance. Details of the hardware configuration are presented, along with the spatial resolution of the system measured as a function of phosphor-screen thickness. The strategies which will be used to measure the transverse and longitudinal emittances are briefly mentioned. The system should be capable of measuring a transverse geometric emittance of around 1 mm-mrad, as will be typical of the ATF beam. 6 refs., 2 figs

Technical Note: Robust measurement of the slice-sensitivity profile in breast tomosynthesis

Energy Technology Data Exchange (ETDEWEB)

Maki, Aili K., E-mail: aili.maki@sri.utoronto.ca; Mainprize, James G. [Physical Sciences Platform, Sunnybrook Research Institute, 2075 Bayview Avenue, Toronto, Ontario M4N 3M5 (Canada); Yaffe, Martin J. [Departments of Medical Imaging and Medical Biophysics, University of Toronto, 2075 Bayview Avenue, Toronto, Ontario M4N 3M5, Canada and Physical Sciences Platform, Sunnybrook Research Institute, 2075 Bayview Avenue, Toronto, Ontario M4N 3M5 (Canada)

2016-08-15

Purpose: The purpose of this work is to improve the repeatability of the measurement of the slice-sensitivity profile (SSP) in reconstructed breast tomosynthesis volumes. Methods: A grid of aluminum ball-bearings (BBs) within a PMMA phantom was imaged on breast tomosynthesis systems from three different manufacturers. The full-width half-maximum (FWHM) values were measured for the SSPs of the BBs in the reconstructed volumes. The effect of transforming the volumes from a Cartesian coordinate system (CCS) to a cone-beam coordinate system (CBCS) on the variability in the FWHM values was assessed. Results: Transforming the volumes from a CCS to a CBCS before measuring the SSPs reduced the coefficient of variation (COV) in the measurements of FWHM in repeated measurements by 56% and reduced the dependence of the FWHM values on the location of the BBs within the reconstructed volume by 76%. Conclusions: Measuring the SSP in the volumes in a CBCS improves the robustness of the measurement.

Vibrating wire for beam profile scanning

Directory of Open Access Journals (Sweden)

S. G. Arutunian

1999-12-01

Full Text Available A method that measures the transverse profile (emittance of the bunch by detecting radiation arising at the scattering of the bunch on scanning wire is widely used. In this work information about bunch scattering is obtained by measuring the oscillation frequency of the tightened scanning wire. In such a way, the system of radiation (or secondary particles extraction and measurement can be removed. The entire unit consists of a compact fork with tightened wire and a scanning system. Normal oscillation frequency of a wire depends on wire tension, its geometric parameters, and, in a second approximation, its elastic characteristics. Normal oscillations are generated by interaction of an alternating current through the wire with magnetic field of a permanent magnet. In this case, it is suggested that the magnetic field of the accelerator (field of dipole magnets or quadrupole magnets be used for excitation of oscillations. The dependence of oscillation frequency on beam scattering is determined by several factors, including changes of wire tension caused by transverse force of the beam and influence of beam self-field. Preliminary calculations show that the influence of wire heating will dominate. We have studied strain gauges on the basis of vibrating wire from various materials (tungsten, beryl bronze, and niobium zirconium alloys. A scheme of normal oscillation generation by alternating current in autogeneration circuit with automatic frequency adjustment was selected. A special method of wire fixation and elimination of transverse degrees of freedom allows us to achieve relative stability better than 10^{-5} during several days at a relative resolution of 10^{-6}. Experimental results and estimates of wire heating of existing scanners show that the wire heats up to a few hundred grades, which is enough for measurements. The usage of wire of micrometer thickness diminishes the problem of wire thermalization speed during the scanning of the bunch.

A method for hardening or curing adhesives for flocking thermally sensitive substrata by means of an electron-beam

International Nuclear Information System (INIS)

Nablo, S.V.; Fussa, A.D.

1975-01-01

The invention relates to a method for hardening or curing adhesives for flocking thermally sensitive substrata by means of an electron-beam. That method consists in accurately adjusting the parameters of irradiation by an electron-beam and the beam velocity so as to obtain, a very rapid hardening of adhesives used for fixing flocking materials, or the like, to thermally sensitive substrate. That can be applied to hardening or curing adhesives for flocking thermally-sensitive substrata which normally restrict the hardening rate [fr

Sensitivity profiles calculated with the UNISENS system

International Nuclear Information System (INIS)

Claro, L.H.; Menezes, A.

1985-01-01

Sensitivity profiles of the multiplication factor and several central reaction ratios for benchmarks ZPR 6/7, ZPR 3/11, FLATTOP-25, GODIVA and BIG-TEN, are presented in grafic form. A possible utilization is showed throught some modification to the ENDF/B-IV data file proposed for version ENDF/B-V. (Author) [pt

A new beam profile monitor and time of flight system for CologneAMS

Energy Technology Data Exchange (ETDEWEB)

Pascovici, G. [CologneAMS, University of Cologne (Germany); Dewald, A., E-mail: dewald@ikp.uni-koeln.de [CologneAMS, University of Cologne (Germany); Institute of Nuclear Physics, University of Cologne (Germany); Heinze, S., E-mail: heinze@ikp.uni-koeln.de [CologneAMS, University of Cologne (Germany); Fink, L.; Mueller-Gatermann, C.; Schiffer, M.; Feuerstein, C. [CologneAMS, University of Cologne (Germany); Pfeiffer, M.; Jolie, J.; Thiel, S.; Zell, K.O.; Arnopolina, O. [Institute of Nuclear Physics, University of Cologne (Germany); Blanckenburg, F. von [GFZ, German Research Centre for Geosciences, Potsdam (Germany)

2013-01-15

A complex beam detector consisting of a high-resolution beam profile monitor (BPM) and a time of flight (TOF) spectrometer with tracking capabilities was designed especially for the special needs of the Cologne center for accelerator mass spectrometry (CologneAMS). The beam detector assembly is designed to match the beam specifications of the 6 MV Tandetron AMS setup and its data acquisition system. It will have a reconfigurable structure, either as a fast TOF subsystem with a ca. 10 cm{sup 2} equivalent active area, or as a more complex BPM-TOF detector with beam tracking capabilities and a larger active area (16 cm{sup 2}). The purpose of this detector is to suppress background during spectrometry of heavy ions (U, Cm, Pu, Am etc.) and to suppress isobaric interferences such as {sup 36}S in {sup 36}Cl spectra.

Carbon filament beam profile monitor for high energy proton-antiproton storage rings

International Nuclear Information System (INIS)

Evans, L.R.; Shafer, R.E.

1979-01-01

The measurement of the evolution of the transverse profile of the stored beams in high energy proton storage rings such as the p-anti p colliders at CERN and at FNAL is of considerable importance. In the present note, a simple monitor is discussed which will allow almost non-destructive measurement of the profile of each individual proton and antiproton bunch separately. It is based on the flying wire technique first used at CEA and more recently at the CPS. A fine carbon filament is passed quickly through the beam, acting as a target for secondary particle production. The flux of secondary particles is measured by two scintillator telescopes, one for protons and one for antiprotons, having an angular acceptance between 30 and 100 mrad. Measurements of secondary particle production performed at FNAL in this angular range show that a very respectable flux can be expected

Studies on the profile measurement of hadron beams by means of residual-gas luminescence and ionization

International Nuclear Information System (INIS)

Boehme, Christian Gerhard Heinrich

2011-01-01

Modern particle accelerators are applied for a long time no more only in the fundamental physical research but in ever larger extent also in the concrete application for instance in the tumor irradiation or the microprocessor fabrication. The precise knowledge of the beam profile is thereby of great importance for the success. But in intermediate-energy hadron accelerators it hitherto not satisfyingly succeeds to measure the beam profiles not disturbingly. These study presents two not beam-disturbing measuring methods, which are based on the ion beam-residual gas interactions of luminescence and ionization. They were developed for different framework conditions at the JESSICA beam place of the COSY accelerator of the Juelich research center, an advance experiment of the planned European Spallation Source (ESS), as well at the proton synchrotron COSY itself, and the iThemba Laboratory for Accelerator Based Science, Somerset West, South Africa. Thereby the studies consider a large range of possible configuration parameters: Particle momenta from 3 MeV/c to 3 GeV/c, pressures from 1 mbar to 10 -11 mbar and time structures from DC beam to beam bunches of 100 ns length. The experimental arrangement, the application ranges, and the advantages and disadvantages of both methods are explained in this book.

Propagation profile of ablation front driven by a nonuniform UV laser beam

International Nuclear Information System (INIS)

Matsushima, I.; Tanimoto, M.; Kasai, T.; Yano, M.

1985-01-01

Spatial profile of ablation front is observed under the irradiation of spatially modulated 0.27-μm laser beam. Propagation depth of the ablation front is derived by means of various methods which detect x-ray radiation from aluminum substrates overcoated with polyethylene layers of different thicknesses. A higher mass ablation rate is observed for the UV laser than the longer wavelength lasers. However, observation with an x-ray television camera shows that the spatial nonuniformity in the laser beam is projected on the ablation front surface without substantial smoothing

Molecular depth profiling of trehalose using a C{sub 60} cluster ion beam

Energy Technology Data Exchange (ETDEWEB)

Wucher, Andreas [Department of Physics, University of Duisburg-Essen, D-47048 Duisburg (Germany)], E-mail: andreas.wucher@uni-due.de; Cheng Juan; Winograd, Nicholas [Department of Chemistry, Pennsylvania State University, University Park, PA 16802 (United States)

2008-12-15

Molecular depth profiling of organic overlayers was performed using a mass selected fullerene ion beam in conjunction with time-of-flight (TOF-SIMS) mass spectrometry. The characteristics of depth profiles acquired on a 300-nm trehalose film on Si were studied as a function of the impact kinetic energy and charge state of the C{sub 60} projectile ions. We find that the achieved depth resolution depends only weakly upon energy.

A setup for measurement of beam stability and position using position sensitive detector for Indus-1

International Nuclear Information System (INIS)

Nathwani, R.K.; Joshi, D.K.; Tyagi, Y.; Soni, R.S.; Puntambekar, T.A.; Pithawa, C.K.

2009-01-01

The 450 MeV electron synchrotron radiation source Indus-1 is operational at RRCAT. A set-up has been developed to measure the relative transverse positional stability of the electron beam and its position with microns resolution using position sensitive photodiodes. The set-up has been installed at the diagnostics beam line of Indus-1. Synchrotron light from photo physics beamline was reflected out by inserting a Ni coated mirror and was focused onto a duo-lateral position sensitive photodiode by using two mirrors of 1.25 meter focal length to obtain unity magnification. The set-up consists of a duo-lateral position sensitive detector (PSD), precision processing electronics and a PC based data acquisition system. A computer program captures the processed signals on to a PC using GPIB interface and displays vertical position of the beam in real time. The paper describes the salient features of the setup developed for measurement of beam stability. (author)

Depth profiling of boron implanted silicon by positron beam

International Nuclear Information System (INIS)

Oevuenc, S.

2004-01-01

Positron depth profiling analyses of low energy implants of silicon aim to observe tbe structure and density of the vacancies generating by implantation and the effect of annealing. This work present the results to several set of data starting S and W parameters. Boron implanted Silicon samples with different implantation energies,20,22,24,and 26 keV are analyzed by Slow positron beam (0-40 keV and 10 5 e + /s )(Variable Energy Positron) at the Positron Centre Delf-HOLLAND

The influence of beam divergence on ion-beam induced surface patterns

International Nuclear Information System (INIS)

Kree, R.; Yasseri, T.; Hartmann, A.K.

2009-01-01

We present a continuum theory and a Monte Carlo model of self-organized surface pattern formation by ion-beam sputtering including effects of beam profiles. Recently, it has turned out that such secondary ion-beam parameters may have a strong influence on the types of emerging patterns. We first discuss several cases, for which beam profiles lead to random parameters in the theory of pattern formation. Subsequently we study the evolution of the averaged height profile in continuum theory and find that the typical Bradley-Harper scenario of dependence of ripple patterns on the angle of incidence can be changed qualitatively. Beam profiles are implemented in Monte Carlo simulations, where we find generic effects on pattern formation. Finally, we demonstrate that realistic beam profiles, taken from experiments, may lead to qualitative changes of surface patterns.

Experimental study of the molecular beam destruction by beam-beam and beam-background scattering

International Nuclear Information System (INIS)

Bossel, U.; Dettleff, G.

1974-01-01

The extraction of flow properties related to the molecular motion normal to stream lines of an expanding gas jet from observed intensity profiles of supersonic beams is critically assessed. The perturbation of the profile curves by various effects is studied for a helium beam. Exponential laws appear to describe scattering effects to a satisfactory degree

Metasurfaces-based holography and beam shaping: engineering the phase profile of light

Directory of Open Access Journals (Sweden)

Scheuer Jacob

2016-08-01

Full Text Available The ability to engineer and shape the phase profile of optical beams is in the heart of any optical element. Be it a simple lens or a sophisticated holographic element, the functionality of such components is dictated by their spatial phase response. In contrast to conventional optical components which rely on thickness variation to induce a phase profile, metasurfaces facilitate the realization of arbitrary phase distributions using large arrays with sub-wavelength and ultrathin (tens of nanometers features. Such components can be easily realized using a single lithographic step and is highly suited for patterning a variety of substrates, including nonplanar and soft surfaces. In this article, we review the recent developments, potential, and opportunities of metasurfaces applications. We focus primarily on flat optical devices, holography, and beam-shaping applications as these are the key ingredients needed for the development of a new generation of optical devices which could find widespread applications in photonics.

Production of custom beam profiles in computer-controlled radiation therapy

International Nuclear Information System (INIS)

Lane, R.G.; Loyd, M.D.; Chow, C.H.; Ekwelundu, E.; Rosen, I.I.

1989-01-01

This paper presents a study to produce custom beam profiles in patients that compensate for variations in patient anatomy and achieve uniform dose distributions in the treatment volume. A conventional treatment field is supplemented by a number of centered and/or offset smaller coincident fields of various sizes. The sizes and positions of these supplemental fields and the doses delivered by them are designed to compensate for variations in external patient contour, internal heterogeneities, and variation in tumor volume shape. A computer-controlled linear accelerator with four independent collimator jaws, a built-in motorized wedge filter, an automatic setup capability, and a patient prescription database is used to deliver these complex treatments automatically by means of multiple overlapping beams. Calculations, measurements, and dose distributions demonstrate the efficacy of this technique

Manipulation of laser-accelerated proton beam profiles by nanostructured and microstructured targets

Directory of Open Access Journals (Sweden)

L. Giuffrida

2017-08-01

Full Text Available Nanostructured and microstructured thin foils have been fabricated and used experimentally as targets to manipulate the spatial profile of proton bunches accelerated through the interaction with high intensity laser pulses (6×10^{19}  W/cm^{2}. Monolayers of polystyrene nanospheres were placed on the rear surfaces of thin plastic targets to improve the spatial homogeneity of the accelerated proton beams. Moreover, thin targets with grating structures of various configurations on their rear sides were used to modify the proton beam divergence. Experimental results are presented, discussed, and supported by 3D particle-in-cell numerical simulations.

A beam profile monitor for small electron beams

International Nuclear Information System (INIS)

Norem, J.

1991-01-01

Measurement of beam properties at the foci of high energy linacs is difficult due to the small size of the waists in proposed and existing accelerators (1 nm -2 μm). This article considers the use of bremsstrahlung radiation from thin foils to measure the size and phase space density these beams using nonimaging optics. The components of the system are described, and the ultimate resolution, evaluated theoretically for the case of the Final Focus Test Beam (FFTB) at Stanford Linear Accelerator Center, is a few nm

Non-uniformly polarized beams across their transverse profiles: an introductory study for undergraduate optics courses

International Nuclear Information System (INIS)

Piquero, Gemma; Vargas-Balbuena, Javier

2004-01-01

We provide a simple theoretical study of beams non-uniformly polarized across their transverse sections which can be introduced in undergraduate optics courses. In order to generate such beams we propose to use a slightly convergent (or divergent) linearly and uniformly polarized beam impinging on an anisotropic uniaxial material with the beam propagation direction along the optic axis. Analytical expressions for the Jones vector, Stokes parameters, ellipticity and azimuth at each point of the transverse section, perpendicular to the propagation direction, are obtained at the output of this system. By means of these parameters a detailed description of the state of polarization across the transverse profile is given

A beam profile monitor for small electron beams

International Nuclear Information System (INIS)

Norem, J.

1991-01-01

Measurement of beam properties at the foci of high energy linacs is difficult due to the small size of the waists in proposed and existing accelerators (1 nm - 2 μ). This paper considers the use of bremsstrahlung radiation from thin foils to measure the size and phase space density these beams using nonimaging optics. The components of the system are described, and the ultimate resolution, evaluated theoretically for the case of the Final Focus Test Beam at Stanford Linear Accelerator Center, is a few nm. 13 refs., 4 figs. 1 tab

Measurement of dynamic wedge angles and beam profiles by means of MRI ferrous sulphate gel dosimetry

Science.gov (United States)

Bengtsson, Magnus; Furre, Torbjørn; Rødal, Jan; Skretting, Arne; Olsen, Dag R.

1996-02-01

The purpose of this study is to examine the possible value of measuring the dose distribution in dynamic wedge photon beams using ferrous sulphate gel phantoms analysed by MRI. The wedge angles and dose profiles were measured for a field size of and for dynamic wedge angles of , , and using a 15 MV photon beam generated from a Clinac 2100 CD (Varian). The dose profiles obtained from MRI ferrous sulphate gel were in good agreement with the dose measurements performed with a diode detector array. Also, the wedge angles determined from the MRI ferrous sulphate gel agreed well with the values obtained by using film dosimetry and with calculations by use of TMS (treatment planning system) (Helax, Uppsala, Sweden). The study demonstrated that MRI ferrous sulphate gel dosimetry is an adequate tool for measurements of some beam characteristics of dynamic radiation fields.

Neutral Probe Beam q-profile measurements in PDX and PBX-M

International Nuclear Information System (INIS)

Kugel, H.W.; Gammel, G.M.; Kaita, R.; Reusch, M.F.; Roberts, D.W.

1988-06-01

Using the Fast Ion Diagnostic Experiment (FIDE) technique, a Neutral Probe Beam (NPB) can be aimed to inject tangentially to a magnetic surface. The resultant ion orbit shifts, due to conservation of canonical toroidal angular momentum, can be measured with a multi-sightline charge-exchange analyzer to yield direct measurements of radial magnetic flux profiles, current density profiles, the radial position of the magnetic axis, flux surface inner and outer edges, q-profiles, and central-q time dependencies. An extensive error analysis was performed on previous PDX q-measurements in circular plasmas and the resulting estimated contributions of various systematic effects are discussed. Preliminary results of fast ion orbit shift measurements at early times in indented PBX-M plasmas are given. Methods for increasing the absolute experimental precision of similar measurements in progress on PBX-M are discussed. 4 refs., 3 figs

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

International Nuclear Information System (INIS)

Habibi, M.; Ghamari, F.

2014-01-01

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

Frequency Characteristics of Surface Wave Generated by Single-Line Pulsed Laser Beam with Two Kinds of Spatial Energy Profile Models: Gaussian and Square-Like

Energy Technology Data Exchange (ETDEWEB)

Seo, Ho Geon; Kim, Myung Hwan; Choi, Sung Ho; Kim, Chung Seok; Jhang, Kyung Young [Hanyang University, Seoul (Korea, Republic of)

2012-08-15

Using a single-line pulsed laser beam is well known as a useful noncontact method to generate a directional surface acoustic wave. In this method, different laser beam energy profiles produce different waveforms and frequency characteristics. In this paper, we considered two typical kinds of laser beam energy profiles, Gaussian and square-like, to find out a difference in the frequency characteristics. To achieve this, mathematical models were proposed first for Gaussian laser beam profile and square-like respectively, both of which depended on the laser beam width. To verify the theoretical models, experimental setups with a cylindrical lens and a line-slit mask were respectively designed to produce a line laser beam with Gaussian spatial energy profile and square-like. The frequency responses of the theoretical models showed good agreement with experimental results in terms of the existence of harmonic frequency components and the shift of the first peak frequencies to low.

Effect of tackifier and crosslinkers on electron beam curable polyurethane pressure sensitive adhesive

International Nuclear Information System (INIS)

Kumar Singh, Anil; Singh Mehra, Dayal; Kumar Niyogi, Utpal; Sabharwal, Sunil; Kumar Khandal, Rakesh

2012-01-01

Polyurethane based pressure sensitive adhesive using monofunctional urethane acrylate and difunctional urethane acrylate has been made using electron beam irradiation. The effect of varying electron beam doses on the adhesion properties viz., peel adhesion, shear adhesion and initial tack has been studied. Effect of tackifier and crosslinkers viz., polymeric methylene diphenyl diisocynate, carbodiimide modified methylene diphenyl diisocynate and triallyl cynurate on adhesion properties as well as on moisture vapor transmission rate and gel content of the polyurethane based pressure sensitive adhesive has also been studied. It was found that with increasing dose, tackifier and crosslinkers concentration, all the adhesion properties viz., peel adhesion, shear adhesion strength and initial tack were increased upto a certain dose, concentration of tackifier and crosslinkers, reached a plateau and then levelled off with further increasing the dose, tackifier and crosslinkers concentration. Similarly, moisture vapor transmission rate was decreased and the gel content increased with increasing dose of electron beam. - Highlights: ► The optimized e-beam dose was 20 kGy. ► Optimized concentration of tackifier was 15% while PMDI, CMDI 6% and TAC 4%. ► CMDI has highest while TAC has lowest adhesion properties. ► Tackifier has highest while TAC has lowest MVTR. ► TAC has highest while tackifier has lowest gel content.

Studies of the Influence of Beam Profile and Cooling Conditions on the Laser Deposition of a Directionally-Solidified Superalloy

Directory of Open Access Journals (Sweden)

Shuo Yang

2018-02-01

Full Text Available In the laser deposition of single crystal and directionally-solidified superalloys, it is desired to form laser deposits with high volume fractions of columnar grains by suppressing the columnar-to-equiaxed transition efficiently. In this paper, the influence of beam profile (circular and square shapes and cooling conditions (natural cooling and forced cooling on the geometric morphology and microstructure of deposits were experimentally studied in the laser deposition of a directionally-solidified superalloy, IC10, and the mechanisms of influence were revealed through a numerical simulation of the thermal processes during laser deposition. The results show that wider and thinner deposits were obtained with the square laser beam than those with the circular laser beam, regardless of whether natural or forced cooling conditions was used. The heights and contact angles of deposits were notably increased due to the reduced substrate temperatures by the application of forced cooling for both laser beam profiles. Under natural cooling conditions, columnar grains formed epitaxially at both the center and the edges of the deposits with the square laser beam, but only at the center of the deposits with the circular laser beam; under forced cooling conditions, columnar grains formed at both the center and the edges of deposits regardless of the laser beam profile. The high ratios of thermal gradient and solidification velocity in the height direction of the deposits were favorable to forming deposits with higher volume fractions of columnar grains.

Simulation calculation for the energy deposition profile and the transmission fraction of intense pulsed electron beam at various incident angles

International Nuclear Information System (INIS)

Yang Hailiang; Qiu Aici; Zhang Jiasheng; Huang Jianjun; Sun Jianfeng

2002-01-01

The incident angles have a heavy effect on the intense pulsed electron beam energy deposition profile, energy deposition fraction and beam current transmission fraction in material. The author presents electron beam energy deposition profile and energy deposition fraction versus electron energy (0.5-2.0 MeV), at various incident angles for three aluminum targets of various thickness via theoretical calculation. The intense pulsed electron beam current transmission fractions versus electron energy (0.4-1.4 MeV) at various incident angles for three thickness of carbon targets were also theoretically calculated. The calculation results indicate that the deposition energy in unit mass of material surface layer increase with the rise of electron beam incident angle, and electron beam with low incident angle (closer to normal incident angle) penetrates deeper into the target material. The electron beams deposit more energy in unit mass of material surface layer at 60 degree-70 degree incident angle

Commissioning and First Results of the Electron Beam Profiler in the Main Injector at Fermilab

Energy Technology Data Exchange (ETDEWEB)

Thurman-Keup, R. [Fermilab; Alvarez, M. [Fermilab; Fitzgerald, J. [Fermilab; Lundberg, C. [Fermilab; Prieto, P. [Fermilab; Zagel, J. [Fermilab; Blokland, W. [Oak Ridge

2017-08-01

The planned neutrino program at Fermilab requires large proton beam intensities in excess of 2 MW. Measuring the transverse profiles of these high intensity beams is challenging and often depends on non-invasive techniques. One such technique involves measuring the deflection of a probe beam of electrons with a trajectory perpendicular to the proton beam. A device such as this is already in use at the Spallation Neutron Source at ORNL and a similar device has been installed in the Main Injector at Fermilab. Commissioning of the device is in progress with the goal of having it operational by the end of the year. The status of the commissioning and initial results will be presented

Scintillation screen materials for beam profile measurements of high energy ion beams

Energy Technology Data Exchange (ETDEWEB)

Krishnakumar, Renuka

2016-06-22

For the application as a transverse ion beam diagnostics device, various scintillation screen materials were analysed. The properties of the materials such as light output, image reproduction and radiation stability were investigated with the ion beams extracted from heavy ion synchrotron SIS-18. The ion species (C, Ne, Ar, Ta and U) were chosen to cover the large range of elements in the periodic table. The ions were accelerated to the kinetic energies of 200 MeV/u and 300 MeV/u extracted with 300 ms pulse duration and applied to the screens. The particle intensity of the ion beam was varied from 10{sup 4} to 10{sup 9} particles per pulse. The screens were irradiated with typically 40 beam pulses and the scintillation light was captured using a CCD camera followed by characterization of the beam spot. The radiation hardness of the screens was estimated with high intensity Uranium ion irradiation. In the study, a linear light output for 5 orders of magnitude of particle intensities was observed from sensitive scintillators and ceramic screens such as Al{sub 2}O{sub 3}:Cr and Al{sub 2}O{sub 3}. The highest light output was recorded by CsI:Tl and the lowest one by Herasil. At higher beam intensity saturation of light output was noticed from Y and Mg doped ZrO{sub 2} screens. The light output from the screen depends not only on the particle intensity but also on the ion species used for irradiation. The light yield (i.e. the light intensity normalised to the energy deposition in the material by the ion) is calculated from the experimental data for each ion beam setting. It is shown that the light yield for light ions is about a factor 2 larger than the one of heavy ions. The image widths recorded exhibit a dependence on the screens material and differences up to 50 % were registered. On radiation stability analysis with high particle intensity of Uranium ions of about 6 x 10{sup 8} ppp, a stable performance in light output and image reproduction was documented from Al

LHCB: A LHCb-VELO module as beam quality monitor for proton therapy beam at the Clatterbridge Centre for Oncology

CERN Multimedia

Casse, G; Patel, G D; Smith, N A; Kacperek, A; Marsland, B

2010-01-01

The progress in detector technology, driven by the needs of particle tracking and vertexing in the present LHC and its upgrade (sLHC), has led to the design of silicon sensors with low mass, high granularity, high speed and unprecedented radiation hardness. The sensors designed for such a harsh environment can be profitably used for instrumenting the control systems of therapeutic hadron beams. The high granularity and readout clock speed are well suited for monitoring continuous beam currents. The low mass allows reduced interference with the beam whilst monitoring its profile with high precision. The high resolution and sensitivity to minimum ionising particles allows monitoring of the beam spot position by measurement of the halo in real time, without any interference with the beam spot used in therapy.

Analytical approach for determining beam profiles in water phantom of symmetric and asymmetric fields of wedged, blocked, and open photon beams.

Science.gov (United States)

Tahmasebi Birgani, Mohamad Javad; Chegeni, Nahid; Arvandi, Shole; Razmjoo Ghalaee, Sasan; Zabihzadeh, Mansoor; Khezerloo, Davood

2013-11-04

Nowadays, in most radiotherapy departments, the commercial treatment planning systems (TPS) used to calculate dose distributions needs to be verified; therefore, quick, easy-to-use, and low-cost dose distribution algorithms are desirable to test and verify the performance of the TPS. In this paper, we put forth an analytical method to calculate the phantom scatter contribution and depth dose on the central axis based on the equivalent square concept. Then, this method was generalized to calculate the profiles at any depth and for several field shapes - regular or irregular fields - under symmetry and asymmetry photon beam conditions. Varian 2100 C/D and Siemens Primus Plus linacs with 6 and 18 MV photon beam were used for irradiations. Percentage depth doses (PDDs) were measured for a large number of square fields for both energies and for 45° wedge, which were employed to obtain the profiles in any depth. To assess the accuracy of the calculated profiles, several profile measurements were carried out for some treatment fields. The calculated and measured profiles were compared by gamma-index calculation. All γ-index calculations were based on a 3% dose criterion and a 3 mm dose-to-agreement (DTA) acceptance criterion. The γ values were less than 1 at most points. However, the maximum γ observed was about 1.10 in the penumbra region in most fields and in the central area for the asymmetric fields. This analytical approach provides a generally quick and fairly accurate algorithm to calculate dose distribution for some treatment fields in conventional radiotherapy.

Ion beam diagnosis

International Nuclear Information System (INIS)

Strehl, P.

1994-04-01

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

Experimental determination of the lateral dose response functions of detectors to be applied in the measurement of narrow photon-beam dose profiles.

Science.gov (United States)

Poppinga, D; Meyners, J; Delfs, B; Muru, A; Harder, D; Poppe, B; Looe, H K

2015-12-21

This study aims at the experimental determination of the detector-specific 1D lateral dose response function K(x) and of its associated rotational symmetric counterpart K(r) for a set of high-resolution detectors presently used in narrow-beam photon dosimetry. A combination of slit-beam, radiochromic film, and deconvolution techniques served to accomplish this task for four detectors with diameters of their sensitive volumes ranging from 1 to 2.2 mm. The particular aim of the experiment was to examine the existence of significant negative portions of some of these response functions predicted by a recent Monte-Carlo-simulation (Looe et al 2015 Phys. Med. Biol. 60 6585-607). In a 6 MV photon slit beam formed by the Siemens Artiste collimation system and a 0.5 mm wide slit between 10 cm thick lead blocks serving as the tertiary collimator, the true cross-beam dose profile D(x) at 3 cm depth in a large water phantom was measured with radiochromic film EBT3, and the detector-affected cross-beam signal profiles M(x) were recorded with a silicon diode, a synthetic diamond detector, a miniaturized scintillation detector, and a small ionization chamber. For each detector, the deconvolution of the convolution integral M(x)  =  K(x)  ∗  D(x) served to obtain its specific 1D lateral dose response function K(x), and K(r) was calculated from it. Fourier transformations and back transformations were performed using function approximations by weighted sums of Gaussian functions and their analytical transformation. The 1D lateral dose response functions K(x) of the four types of detectors and their associated rotational symmetric counterparts K(r) were obtained. Significant negative curve portions of K(x) and K(r) were observed in the case of the silicon diode and the diamond detector, confirming the Monte-Carlo-based prediction (Looe et al 2015 Phys. Med. Biol. 60 6585-607). They are typical for the perturbation of the secondary electron field by a detector with

Overview of laserwire beam profile and emittance measurements for high power proton accelerators

CERN Document Server

Gibson, S M; Bosco, A; Gabor, C; Pozimski, J; Savage, P; Hofmann, T

2013-01-01

Laserwires were originally developed to measure micron-sized electron beams via Compton scattering, where traditional wire scanners are at the limit of their resolution. Laserwires have since been applied to larger beamsize, high power H$^-$ ion beams, where the non-invasive method can probe beam densities that would damage traditional diagnostics. While photo-detachment of H$^-$ ions is now routine to measure beam profiles, extending the technique to transverse and longitudinal emittance measurements is a key aim of the laserwire emittance scanner under construction at the Front End Test Stand (FETS) at the RAL. A pulsed, 30 kHz, 8kW peak power laser is fibrecoupled to motorized collimating optics, which controls the position and thickness of the laserwire delivered to the H- interaction chamber. The laserwire slices out a beamlet of neutralized particles, which propagate to a downstream scintillator and camera. The emittance is reconstructed from 2D images as the laserwire position is scanned. Results from ...

Shape optimization and sensitivity of compliant beams for prescribed load-displacement response

NARCIS (Netherlands)

Radaelli, G.; Herder, J.L.

2016-01-01

This paper presents the shape optimization of a compliant beam for prescribed load-displacements response. The analysis of the design is based on the isogeometric analysis framework for an enhanced fidelity between designed and analysed shape. The sensitivities used for an improved optimization

A very sensitive nonintercepting beam average velocity monitoring system for the TRIUMF 300-keV injection line

International Nuclear Information System (INIS)

Yin, Y.; Laxdal, R.E.; Zelenski, A.; Ostroumov, P.

1997-01-01

A nonintercepting beam velocity monitoring system has been installed in the 300-keV injection line of the TRIUMF cyclotron to reproduce the injection energy for beam from different ion sources and to monitor any beam energy fluctuations. By using a programmable beam signal leveling method the system can work with a beam current dynamic range of 50 dB. Using synchronous detection, the system can detect 0.5 eV peak-to-peak energy modulation of the beam, sensitivity is 1.7x10 -6 . The paper will describe the principle and beam measurement results. copyright 1997 American Institute of Physics

Longitudinal profile diagnostic scheme with subfemtosecond resolution for high-brightness electron beams

Directory of Open Access Journals (Sweden)

G. Andonian

2011-07-01

Full Text Available High-resolution measurement of the longitudinal profile of a relativistic electron beam is of utmost importance for linac based free-electron lasers and other advanced accelerator facilities that employ ultrashort bunches. In this paper, we investigate a novel scheme to measure ultrashort bunches (subpicosecond with exceptional temporal resolution (hundreds of attoseconds and dynamic range. The scheme employs two orthogonally oriented deflecting sections. The first imparts a short-wavelength (fast temporal resolution horizontal angular modulation on the beam, while the second imparts a long-wavelength (slow angular kick in the vertical dimension. Both modulations are observable on a standard downstream screen in the form of a streaked sinusoidal beam structure. We demonstrate, using scaled variables in a quasi-1D approximation, an expression for the temporal resolution of the scheme and apply it to a proof-of-concept experiment at the UCLA Neptune high-brightness injector facility. The scheme is also investigated for application at the SLAC NLCTA facility, where we show that the subfemtosecond resolution is sufficient to resolve the temporal structure of the beam used in the echo-enabled free-electron laser. We employ beam simulations to verify the effect for typical Neptune and NLCTA parameter sets and demonstrate the feasibility of the concept.

Gene Expression Profile of Proton Beam Irradiated Breast Cancer Stem Cells

Energy Technology Data Exchange (ETDEWEB)

Jung, Myung Hwan; Park, Jeong Chan [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2015-05-15

Cancer stem cells (CSCs) possess characteristics associated with normal stem cells. The mechanisms regulating CSC radio-resistance, including to proton beam, remain unclear. They showed that a subset of cells expressing CD44 with weak or no CD24 expression could establish new tumors in xenograft mice. Recently, BCSC-targeting therapies have been evaluated by numerous groups. Strategies include targeting BCSC self-renewal, indirectly targeting the microenvironment, and directly killing BCSCs by chemical agents that induce differentiation, immunotherapy, and oncolytic viruses. However, the mechanisms regulating CSC radio-resistance, particularly proton beam resistance, remain unclear. The identification of CSC-related gene expression patterns would make up offer data for better understanding CSCs properties. In this study we investigated the gene expression profile of BCSCs isolation from MCF-7 cell line. Reducing BCSC resistance to pulsed proton beams is essential to improve therapeutic efficacy and decrease the 5-year recurrence rate. In this respect, the information of the level of gene expression patterns in BCSCs is attractive for understanding molecular mechanisms of radio-resistance of BCSCs.

Dual beam organic depth profiling using large argon cluster ion beams

Science.gov (United States)

Holzweber, M; Shard, AG; Jungnickel, H; Luch, A; Unger, WES

2014-01-01

Argon cluster sputtering of an organic multilayer reference material consisting of two organic components, 4,4′-bis[N-(1-naphthyl-1-)-N-phenyl- amino]-biphenyl (NPB) and aluminium tris-(8-hydroxyquinolate) (Alq3), materials commonly used in organic light-emitting diodes industry, was carried out using time-of-flight SIMS in dual beam mode. The sample used in this study consists of a ∽400-nm-thick NPB matrix with 3-nm marker layers of Alq3 at depth of ∽50, 100, 200 and 300 nm. Argon cluster sputtering provides a constant sputter yield throughout the depth profiles, and the sputter yield volumes and depth resolution are presented for Ar-cluster sizes of 630, 820, 1000, 1250 and 1660 atoms at a kinetic energy of 2.5 keV. The effect of cluster size in this material and over this range is shown to be negligible. © 2014 The Authors. Surface and Interface Analysis published by John Wiley & Sons Ltd. PMID:25892830

iCycle: Integrated, multicriterial beam angle, and profile optimization for generation of coplanar and noncoplanar IMRT plans

International Nuclear Information System (INIS)

Breedveld, Sebastiaan; Storchi, Pascal R. M.; Voet, Peter W. J.; Heijmen, Ben J. M.

2012-01-01

Purpose: To introduce iCycle, a novel algorithm for integrated, multicriterial optimization of beam angles, and intensity modulated radiotherapy (IMRT) profiles. Methods: A multicriterial plan optimization with iCycle is based on a prescription called wish-list, containing hard constraints and objectives with ascribed priorities. Priorities are ordinal parameters used for relative importance ranking of the objectives. The higher an objective priority is, the higher the probability that the corresponding objective will be met. Beam directions are selected from an input set of candidate directions. Input sets can be restricted, e.g., to allow only generation of coplanar plans, or to avoid collisions between patient/couch and the gantry in a noncoplanar setup. Obtaining clinically feasible calculation times was an important design criterium for development of iCycle. This could be realized by sequentially adding beams to the treatment plan in an iterative procedure. Each iteration loop starts with selection of the optimal direction to be added. Then, a Pareto-optimal IMRT plan is generated for the (fixed) beam setup that includes all so far selected directions, using a previously published algorithm for multicriterial optimization of fluence profiles for a fixed beam arrangement Breedveld et al.[Phys. Med. Biol. 54, 7199-7209 (2009)]. To select the next direction, each not yet selected candidate direction is temporarily added to the plan and an optimization problem, derived from the Lagrangian obtained from the just performed optimization for establishing the Pareto-optimal plan, is solved. For each patient, a single one-beam, two-beam, three-beam, etc. Pareto-optimal plan is generated until addition of beams does no longer result in significant plan quality improvement. Plan generation with iCycle is fully automated. Results: Performance and characteristics of iCycle are demonstrated by generating plans for a maxillary sinus case, a cervical cancer patient, and a

UV laser beam profile measurement by means of the photoelectric effect on the wires of a proportional chamber

International Nuclear Information System (INIS)

Prokoviev, O.; Seiler, P.G.

1989-01-01

A simple technique to measure the profiles of pulsed UV laser beams is described. Irradiating a cathode wire of a proportional chamber with UV laser shots results in signals from the anode wire whose amplitudes are proportional to the UV light intensity. Profile scanning is performed by shifting the chamber across the beam. The chamber can also be used with reversed polarities. This leads to avalanches developing outwardly from the signal wire. In this case we observe a quadratic dependence of the pulse height on the UV light intensity. (orig.)

Specialty flat-top beam delivery fibers with controlled beam parameter product

Science.gov (United States)

Jollivet, C.; Farley, K.; Conroy, M.; Abramczyk, J.; Belke, S.; Becker, F.; Tankala, K.

2016-03-01

Beam delivery fibers have been used widely for transporting the optical beams from the laser to the subject of irradiation in a variety of markets including industrial, medical and defense applications. Standard beam delivery fibers range from 50 to 1500 μm core diameter and are used to guide CW or pulsed laser light, generated by solid state, fiber or diode lasers. Here, we introduce a novel fiber technology capable of simultaneously controlling the beam profile and the angular divergence of single-mode (SM) and multi-mode (MM) beams using a single-optical fiber. Results of beam transformation from a SM to a MM beam with flat-top intensity profile are presented in the case of a controlled BPP at 3.8 mm*mrad. The scaling capabilities of this flat-top fiber design to achieve a range of BPP values while ensuring a flat-top beam profile are discussed. In addition, we demonstrate, for the first time to the best of our knowledge, the homogenizer capabilities of this novel technology, able to transform random MM beams into uniform flat-top beam profiles with very limited impact on the beam brightness. This study is concluded with a discussion on the scalability of this fiber technology to fit from 50 up to 1500 μm core fibers and its potential for a broader range of applications.

Modification of NUR II neutron beam profile of MINT TRIGA MARK II research reactor for digital neutron radiography

International Nuclear Information System (INIS)

Muhammad Rawi Mohamed Zin; Azali Muhammad; Abdul Aziz Mohamed; Rafhayudi Jamro; Syed Nasaruddin Syed Idris; Ng Aik Hao; Rosly Jaafar

2006-01-01

A cone neutron beam collimated by a 5.4 cm aperture produced in the Neutron Radiography II (NUR II) via a step divergence collimator had to be modified to fulfill 5 cm x 6 cm dimension of the scintillation screen placed in the charge couple device (ccd) camera. The required convergence neutron beam was obtained by a simple collimator-beam plug plugged in front of the NUR II beam port. The calculations involved in designing the collimator-beam plug had to take into account not only the neutron beam profiling but also the neutron and gamma shielding and are discussed in this article. (Author)

SU-F-T-478: Effect of Deconvolution in Analysis of Mega Voltage Photon Beam Profiles

Energy Technology Data Exchange (ETDEWEB)

Muthukumaran, M [Apollo Speciality Hospitals, Chennai, Tamil Nadu (India); Manigandan, D [Fortis Cancer Institute, Mohali, Punjab (India); Murali, V; Chitra, S; Ganapathy, K [Apollo Speciality Hospital, Chennai, Tamil Nadu (India); Vikraman, S [JAYPEE HOSPITAL- RADIATION ONCOLOGY, Noida, UTTAR PRADESH (India)

2016-06-15

Purpose: To study and compare the penumbra of 6 MV and 15 MV photon beam profiles after deconvoluting different volume ionization chambers. Methods: 0.125cc Semi-Flex chamber, Markus Chamber and PTW Farmer chamber were used to measure the in-plane and cross-plane profiles at 5 cm depth for 6 MV and 15 MV photons. The profiles were measured for various field sizes starting from 2×2 cm till 30×30 cm. PTW TBA scan software was used for the measurements and the “deconvolution” functionality in the software was used to remove the volume averaging effect due to finite volume of the chamber along lateral and longitudinal directions for all the ionization chambers. The predicted true profile was compared and the change in penumbra before and after deconvolution was studied. Results: After deconvoluting the penumbra decreased by 1 mm for field sizes ranging from 2 × 2 cm till 20 x20 cm. This is observed for along both lateral and longitudinal directions. However for field sizes from 20 × 20 till 30 ×30 cm the difference in penumbra was around 1.2 till 1.8 mm. This was observed for both 6 MV and 15 MV photon beams. The penumbra was always lesser in the deconvoluted profiles for all the ionization chambers involved in the study. The variation in difference in penumbral values were in the order of 0.1 till 0.3 mm between the deconvoluted profile along lateral and longitudinal directions for all the chambers under study. Deconvolution of the profiles along longitudinal direction for Farmer chamber was not good and is not comparable with other deconvoluted profiles. Conclusion: The results of the deconvoluted profiles for 0.125cc and Markus chamber was comparable and the deconvolution functionality can be used to overcome the volume averaging effect.

Sensitive beam current measurement for FAIR

Energy Technology Data Exchange (ETDEWEB)

Schwickert, Marcus; Kurian, Febin; Reeg, Hansjoerg [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Darmstadt (Germany); Seidel, Paul; Neubert, Ralf [Friedrich-Schiller-Universitaet Jena (Germany); Geithner, Rene; Vodel, Wolfgang [Helmholtz-Institut Jena (Germany)

2012-07-01

Presently FAIR, the Facility for Antiproton and Ion Research, entered the final planning phase at GSI. The new accelerator facility requires precise devices for beam current measurements due to the large dynamics in beam intensities for the various synchrotrons, transport lines and storage rings. We report on the actual developments of beam diagnostic devices for the measurement of beam intensities ranging from 5 x 10{sup 11} uranium ions down to the detection of less than 10{sup 4} antiprotons. This contribution gives an overview of the planned instruments with a focus on non-intercepting beam current transformers, and summarizes the on-going development of a cryogenic current comparator.

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

Energy Technology Data Exchange (ETDEWEB)

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

2015-02-26

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

Electron beam and optical depth profiling of quasibulk GaN

International Nuclear Information System (INIS)

Chernyak, L.; Osinsky, A.; Nootz, G.; Schulte, A.; Jasinski, J.; Benamara, M.; Liliental-Weber, Z.; Look, D. C.; Molnar, R. J.

2000-01-01

Electron beam and optical depth profiling of thick (5.5--64 μm) quasibulk n-type GaN samples, grown by hydride vapor-phase epitaxy, were carried out using electron beam induced current (EBIC), microphotoluminescence (PL), and transmission electron microscopy (TEM). The minority carrier diffusion length, L, was found to increase linearly from 0.25 μm, at a distance of about 5 μm from the GaN/sapphire interface, to 0.63 μm at the GaN surface, for a 36-μm-thick sample. The increase in L was accompanied by a corresponding increase in PL band-to-band radiative transition intensity as a function of distance from the GaN/sapphire interface. We attribute the latter changes in PL intensity and minority carrier diffusion length to a reduced carrier mobility and lifetime at the interface, due to scattering at threading dislocations. The results of EBIC and PL measurements are in good agreement with the values for dislocation density obtained using TEM

Conceptual design of elliptical cavities for intensity and position sensitive beam measurements in storage rings

International Nuclear Information System (INIS)

Sanjari, M S; Chen, X; Hülsmann, P; Litvinov, Yu A; Nolden, F; Piotrowski, J; Steck, M; Stöhlker, Th

2015-01-01

Position sensitive beam monitors are indispensable for the beam diagnostics in storage rings. Apart from their applications in the measurements of beam parameters, they can be used in non-destructive in-ring decay studies of radioactive ion beams as well as enhancing precision in the isochronous mass measurement technique. In this work, we introduce a novel approach based on cavities with elliptical cross-section, in order to compensate the limitations of known designs for the application in ion storage rings. The design is aimed primarily for future heavy ion storage rings of the FAIR project. The conceptual design is discussed together with simulation results. (paper)

Modification of mechanical properties of Si crystal irradiated by Kr-beam

International Nuclear Information System (INIS)

Guo, Xiaowei; Momota, Sadao; Nitta, Noriko; Yamaguchi, Takaharu; Sato, Noriyuki; Tokaji, Hideto

2015-01-01

Graphical abstract: - Highlights: • Modification of mechanical properties of silicon crystal irradiated by Kr-beam was observed by means of continuous measurements of nano-indentation technique. • Modified mechanical properties show fluence-dependence. • Young's modulus is more sensitive to crystal to amorphous phase transition while hardness is more sensitive to damage induced by ion beam irradiation. • The depth profile of modified mechanical properties have a potential application of determining the longitudinal size of phase transition region induced by nanoindentation. - Abstract: The application of ion-beam irradiation in fabrication of structures with micro-/nanometer scale has achieved striking improvement. However, an inevitable damage results in the change of mechanical properties in irradiated materials. To investigate the relation between mechanical properties and ion-irradiation damages, nanoindentation was performed on crystalline silicon irradiated by Kr-beam with an energy of 240 keV. Modified Young's modulus and nanohardness, provided from the indentation, indicated fluence dependence. Stopping and range of ions in matter (SRIM) calculation, transmission electron microscopy (TEM) observation, and Rutherford backscattering-channeling (RBS-C) measurement were utilized to understand the irradiation effect on mechanical properties. In addition, the longitudinal size of the phase transition region induced by indentation was firstly evaluated based on the depth profile of modified nanohardness

First-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Beam Profiles and Window Functions

Science.gov (United States)

Page, L.; Barnes, C.; Hinshaw, G.; Spergel, D. N.; Weiland, J. L.; Wollack, E.; Bennett, C. L.; Halpern, M.; Jarosik, N.; Kogut, A.; Limon, M.; Meyer, S. S.; Tucker, G. S.; Wright, E. L.

2003-09-01

Knowledge of the beam profiles is of critical importance for interpreting data from cosmic microwave background experiments. In this paper, we present the characterization of the in-flight optical response of the WMAP satellite. The main-beam intensities have been mapped to the satellite in the same observing mode as for CMB observations. The beam patterns closely follow the prelaunch expectations. The full width at half-maximum is a function of frequency and ranges from 0.82d at 23 GHz to 0.21d at 94 GHz; however, the beams are not Gaussian. We present (a) the beam patterns for all 10 differential radiometers, showing that the patterns are substantially independent of polarization in all but the 23 GHz channel; (b) the effective symmetrized beam patterns that result from WMAP's compound spin observing pattern; (c) the effective window functions for all radiometers and the formalism for propagating the window function uncertainty; and (d) the conversion factor from point-source flux to antenna temperature. A summary of the systematic uncertainties, which currently dominate our knowledge of the beams, is also presented. The constancy of Jupiter's temperature within a frequency band is an essential check of the optical system. The tests enable us to report a calibration of Jupiter to 1%-3% accuracy relative to the CMB dipole. WMAP is the result of a partnership between Princeton University and the NASA Goddard Space Flight Center. Scientific guidance is provided by the WMAP Science Team.

Multi-channel electronics for secondary emission grid profile monitor of TTF linac

International Nuclear Information System (INIS)

Reingardt-Nikoulin, P.; Gaidash, V.; Mirzojan, A.; Kocharyan, V.; Noelle, D.

2004-01-01

According to the TTF beam experimental program, a measurement f the time dependence of the energy spread within the bunch train should be done by means of a standard device for profile measurements, that is Secondary Emission Grid (SEMG). SEMG on the high-energy TTF beam is placed in the focal plane of the magnet spectrometer. It should measure the total energy spread in the range from 0.1% up to a few percents for any single or any group of electron bunches in the bunch train of TTF Linac. SEMG profile measurements with new high sensitive electronics are described. Beam results of SEMG Monitor test are given for two modifications of an electronic preamplifier

Small-sized monitor of beam current and profile for the proton pulse electrostatic accelerator

International Nuclear Information System (INIS)

Getmanov, V.N.

1985-01-01

Design and principle of operation of current monitor and beam profile of range-coordinate type are described. Monitor operation peculiarities are discussed using diagnostics of a beam of 330-420 keV electrostatic pulse proton accelerator with a beam current of up to 20 mA, at a current density of up to 23 mA x cm -2 and wth pulse duraton of about 20 μs. The monitor consists of a vacuum-dense foil of 3.0+-0.1 μm in thickness (or 0.81+-0.0x- mg x cm -2 ) two grid electrodes, each containing 12 wires, and as solid copper bottom. Foil serves for chopping off background particles with a path lesser 3.0 μm and stands thermal pulse load up to 0.5 J/cm -2 . Grid electrode wires are oriented perpendicularly to lach other and form a two-coordinate secondary-emisson roughness indicator. The bothhom is used for measuring an absolute value of beam current

Elemental thin film depth profiles by ion beam analysis using simulated annealing - a new tool

International Nuclear Information System (INIS)

Jeynes, C; Barradas, N P; Marriott, P K; Boudreault, G; Jenkin, M; Wendler, E; Webb, R P

2003-01-01

Rutherford backscattering spectrometry (RBS) and related techniques have long been used to determine the elemental depth profiles in films a few nanometres to a few microns thick. However, although obtaining spectra is very easy, solving the inverse problem of extracting the depth profiles from the spectra is not possible analytically except for special cases. It is because these special cases include important classes of samples, and because skilled analysts are adept at extracting useful qualitative information from the data, that ion beam analysis is still an important technique. We have recently solved this inverse problem using the simulated annealing algorithm. We have implemented the solution in the 'IBA DataFurnace' code, which has been developed into a very versatile and general new software tool that analysts can now use to rapidly extract quantitative accurate depth profiles from real samples on an industrial scale. We review the features, applicability and validation of this new code together with other approaches to handling IBA (ion beam analysis) data, with particular attention being given to determining both the absolute accuracy of the depth profiles and statistically accurate error estimates. We include examples of analyses using RBS, non-Rutherford elastic scattering, elastic recoil detection and non-resonant nuclear reactions. High depth resolution and the use of multiple techniques simultaneously are both discussed. There is usually systematic ambiguity in IBA data and Butler's example of ambiguity (1990 Nucl. Instrum. Methods B 45 160-5) is reanalysed. Analyses are shown: of evaporated, sputtered, oxidized, ion implanted, ion beam mixed and annealed materials; of semiconductors, optical and magnetic multilayers, superconductors, tribological films and metals; and of oxides on Si, mixed metal silicides, boron nitride, GaN, SiC, mixed metal oxides, YBCO and polymers. (topical review)

Interaction of the modulated electron beam with inhomogeneous plasma: plasma density profile deformation and langmuir waves excitation

International Nuclear Information System (INIS)

Anisimov, I.O.; Kelnyk, O.I.; Soroka, S.V.; Siversky, T.V.

2005-01-01

Nonlinear deformation of the initially linear plasma density profile due to the modulated electron beam is studied via computer simulation. In the initial time period the field slaves to the instantaneous profile of the plasma density. Langmuir waves excitation is suppressed by the density profile deformation. The character of the plasma density profile deformation for the late time period depends significantly on the plasma properties. Particularly, for plasma with hot electrons quasi-periodic generation of ion-acoustic pulses takes place in the vicinity of the initial point of plasma resonance

Application of Metal-Semiconductor-Metal (MSM) Photodetectors for Transverse and Longitudinal Intra-Bunch Beam Diagnostics

CERN Document Server

Steinhagen, R J; Boland, M J; Lucas, T G; Rassool, R P

2013-01-01

The performance reach of modern accelerators is often governed by the ability to reliably measure and control the beam stability. In high-brightness lepton and high-energy hadron accelerators, the use of optical diagnostic techniques is becoming more widespread as the required bandwidth, resolution and high RF beam power level involved limit the use of traditional electro-magnetic RF pick-up based methods. This contribution discusses the use of fibre-coupled ultra-fast Metal-Semiconductor-Metal Photodetectors (MSM-PD) as an alternative, dependablemeans to measure signals derived from electro-optical and synchrotron-light based diagnostics systems. It describes the beam studies performed at CERN’s CLIC Test Facility (CTF3) and the Australian Synchrotron to assess the feasibility of this technology as a robust, wide-band and sensitive technique for measuring transverse intra-bunch and bunch-by-bunch beam oscillations, longitudinal beam profiles, un-bunched beam population and beam-halo profiles. The amplifica...

2D electron density profile measurement in tokamak by laser-accelerated ion-beam probe.

Science.gov (United States)

Chen, Y H; Yang, X Y; Lin, C; Wang, L; Xu, M; Wang, X G; Xiao, C J

2014-11-01

A new concept of Heavy Ion Beam Probe (HIBP) diagnostic has been proposed, of which the key is to replace the electrostatic accelerator of traditional HIBP by a laser-driven ion accelerator. Due to the large energy spread of ions, the laser-accelerated HIBP can measure the two-dimensional (2D) electron density profile of tokamak plasma. In a preliminary simulation, a 2D density profile was reconstructed with a spatial resolution of about 2 cm, and with the error below 15% in the core region. Diagnostics of 2D density fluctuation is also discussed.

Beam electron microprobe

CERN Document Server

Stoller, D; Muterspaugh, M W; Pollock, R E

1999-01-01

A beam profile monitor based on the deflection of a probe electron beam by the electric field of a stored, electron-cooled proton beam is described and first results are presented. Electrons were transported parallel to the proton beam by a uniform longitudinal magnetic field. The probe beam may be slowly scanned across the stored beam to determine its intensity, position, and size. Alternatively, it may be scanned rapidly over a narrow range within the interior of the stored beam for continuous observation of the changing central density during cooling. Examples of a two dimensional charge density profile obtained from a raster scan and of a cooling alignment study illustrate the scope of measurements made possible by this device.

Sensitivity of the OMI ozone profile retrieval (OMO3PR) to a priori assumptions

NARCIS (Netherlands)

Mielonen, T.; De Haan, J.F.; Veefkind, J.P.

2014-01-01

We have assessed the sensitivity of the operational OMI ozone profile retrieval (OMO3PR) algorithm to a number of a priori assumptions. We studied the effect of stray light correction, surface albedo assumptions and a priori ozone profiles on the retrieved ozone profile. Then, we studied how to

Initial time-resolved particle beam profile measurements at the Advanced Photon Source

International Nuclear Information System (INIS)

Yang, B.X.; Lumpkin, A.H.

1995-01-01

The commissioning of the 7-GeV Advanced Photon Source (APS) storage ring began in early 1995. Characterization of the stored particle beam properties involved time-resolved transverse and longitudinal profile measurements using optical synchrotron radiation (OSR) monitors. Early results include the observation of the beam on a single turn, measurements of the transverse beam sizes after damping using a 100 μs integration time (σ x ∼ 150 ± 25 μm, σ γ ∼ 65 ± 25 μm, depending on vertical coupling), and measurement of the bunch length (σ τ ∼ 25 to 55 ps, depending on the charge per bunch). The results are consistent with specifications and predictions based on the 8.2 nm-rad natural emittance, the calculated lattice parameters, and vertical coupling less than 10%. The novel, single-element focusing mirror for the photon transport line and the dual-sweep streak camera techniques which allow turn-by-turn measurements will also be presented. The latter measurements are believed to be the first of their kind on a storage ring in the USA

An Electromagnetic Beam Converter

DEFF Research Database (Denmark)

2009-01-01

The present invention relates to an electromagnetic beam converter and a method for conversion of an input beam of electromagnetic radiation having a bell shaped intensity profile a(x,y) into an output beam having a prescribed target intensity profile l(x',y') based on a further development...

Ion acceleration in electrostatic collisionless shock: on the optimal density profile for quasi-monoenergetic beams

Science.gov (United States)

Boella, E.; Fiúza, F.; Stockem Novo, A.; Fonseca, R.; Silva, L. O.

2018-03-01

A numerical study on ion acceleration in electrostatic shock waves is presented, with the aim of determining the best plasma configuration to achieve quasi-monoenergetic ion beams in laser-driven systems. It was recently shown that tailored near-critical density plasmas characterized by a long-scale decreasing rear density profile lead to beams with low energy spread (Fiúza et al 2012 Phys. Rev. Lett. 109 215001). In this work, a detailed parameter scan investigating different plasma scale lengths is carried out. As result, the optimal plasma spatial scale length that allows for minimizing the energy spread while ensuring a significant reflection of ions by the shock is identified. Furthermore, a new configuration where the required profile has been obtained by coupling micro layers of different densities is proposed. Results show that this new engineered approach is a valid alternative, guaranteeing a low energy spread with a higher level of controllability.

Spatial variability of the aspect sensitivity of VHF radar echoes in the troposphere and lower stratosphere during jet stream passages

Directory of Open Access Journals (Sweden)

J. G. Yoe

Full Text Available The aspect sensitivity of SOUSY-VHF-radar oblique-beam echoes from the troposphere and lower stratosphere has been examined for a number of jet stream passages during the years 1990 - 1992. When the core of the jet is overhead or nearly so, vertical profiles of the aspect sensitivity display two notable features. First, the distinction between mainly isotropic and strongly aspect-sensitive echoes in the troposphere and the lower stratosphere, respectively, often reported for measurements made during calm conditions, does not necessarily prevail in the vicinity of the jet stream. Second, echoes obtained at altitudes near the height of the horizontal wind maximum are found to be more aspect sensitive for beams directed parallel to the horizontal flow or nearly so, than for other beam directions. It is demonstrated that time-averaged horizontal wind speeds estimated from the radar data, taking into account the reduced effective oblique-beam zenith angle resulting from aspect sensitivity, may exceed uncorrected wind speeds by as much as 10 m s^-1 in these circumstances. Implications for wind profiling and for describing the backscattering process are discussed. Doppler spectral widths examined for one jet stream passage are found to be narrower in a beam aligned with the horizontal wind at heights near the wind speed maximum than corresponding widths measured in a beam projected at right angles to the jet. The narrowest spectra thus coincide with the most aspect-sensitive echoes, consistent with the hypothesis that such returns result from specular backscattering processes.

Studying wedge factors and beam profiles for physical and enhanced dynamic wedges

Directory of Open Access Journals (Sweden)

Ahmad Misbah

2010-01-01

Full Text Available This study was designed to investigate variation in Varian′s Physical and Enhanced Dynamic Wedge Factors (WF as a function of depth and field size. The profiles for physical wedges (PWs and enhanced dynamic wedges (EDWs were also measured using LDA-99 array and compared for confirmation of EDW angles at different depths and field sizes. WF measurements were performed in water phantom using cylindrical 0.66 cc ionization chamber. WF was measured by taking the ratio of wedge and open field ionization data. A normalized wedge factor (NWF was introduced to circumvent large differences between wedge factors for different wedge angles. A strong linear dependence of PW Factor (PWF with depth was observed. Maximum variation of 8.9% and 4.1% was observed for 60° PW with depth at 6 and 15 MV beams respectively. The variation in EDW Factor (EDWF with depth was almost negligible and less than two per cent. The highest variation in PWF as a function of field size was 4.1% and 3.4% for thicker wedge (60° at 6 and 15 MV beams respectively and decreases with decreasing wedge angle. EDWF shows strong field size dependence and significant variation was observed for all wedges at both photon energies. Differences in profiles between PW and EDW were observed on toe and heel sides. These differences were dominant for larger fields, shallow depths, thicker wedges and low energy beam. The study indicated that ignoring depth and field size dependence of WF may result in under/over dose to the patient especially doing manual point dose calculation.

Analysis of Relative Biological Effectiveness of Proton Beams and Isoeffective Dose Profiles Using Geant4

Directory of Open Access Journals (Sweden)

Hosseini M. A.

2017-06-01

Full Text Available Background: The assessment of RBE quantity in the treatment of cancer tumors with proton beams in treatment planning systems (TPS is of high significance. Given the significance of the issue and the studies conducted in the literature, this quantity is fixed and is taken as equal to 1.1. Objective: The main objective of this study was to assess RBE quantity of proton beams and their variations in different depths of the tumor. This dependency makes RBE values used in TPS no longer be fixed as they depend on the depth of the tumor and therefore this dependency causes some changes in the physical dose profile. Materials and Methods: The energy spectrum of protons was measured at various depths of the tumor using proton beam simulations and well as the complete simulation of a cell to a pair of DNA bases through Monte Carlo GEANT4. The resulting energy spectrum was used to estimate the number of double-strand breaks generated in cells. Finally, RBE values were calculated in terms of the penetration depth in the tumor. Results and Conclusion: The simulation results show that the RBE value not fixed terms of the depth of the tumor and it differs from the clinical value of 1.1 at the end of the dose profile and this will lead to a non-uniform absorbed dose profile. Therefore, to create a uniform impact dose area, deep-finishing systems need to be designed by taking into account deep RBE values.

Slice sensitivity profiles and pixel noise of multi-slice CT in comparison with single-slice CT

International Nuclear Information System (INIS)

Schorn, C.; Obenauer, S.; Funke, M.; Hermann, K.P.; Kopka, L.; Grabbe, E.

1999-01-01

Purpose: Presentation and evaluation of slice sensitivity profile and pixel noise of multi-slice CT in comparison to single-slice CT. Methods: Slice sensitivity profiles and pixel noise of a multi-slice CT equiped with a 2D matrix detector array and of a single-slice CT were evaluated in phantom studies. Results: For the single-slice CT the width of the slice sensitivity profiles increased with increasing pitch. In spite of a much higher table speed the slice sensitivity profiles of multi-slice CT were narrower and did not increase with higher pitch. Noise in single-slice CT was independent of pitch. For multi-slice CT noise increased with higher pitch and for the higher pitch decreased slightly with higher detector row collimation. Conclusions: Multi-slice CT provides superior z-resolution and higher volume coverage speed. These qualities fulfill one of the prerequisites for improvement of 3D postprocessing. (orig.) [de

Spatial and temporal beam profile monitor with nanosecond resolution for CERN's Linac4 and Superconducting Proton Linac

CERN Document Server

Hori, M

2008-01-01

The Linac4, now being developed at CERN, will provide 160-MeV H- beams of high intensity . Before this beam can be injected into the CERN Proton Synchrotron Booster or future Superconducting Proton Linac for further acceleration, some sequences of 500-ps-long micro-bunches must be removed from it, using a beam chopper. These bunches, if left in the beam, would fall outside the longitudinal acceptance of the accelerators and make them radioactive. We developed a monitor to measure the time structure and spatial profile of this chopped beam, with respective resolutions and . Its large active area and dynamic range also allows investigations of beam halos. The ion beam first struck a carbon foil, and secondary electrons emerging from the foil were accelerated by a series of parallel grid electrodes. These electrons struck a phosphor screen, and the resulting image of the scintillation light was guided to a thermoelectrically cooled, charge-coupled device camera. The time resolution was attained by applying high-...

Status of multigroup sensitivity profiles and covariance matrices available from the radiation shielding information center

International Nuclear Information System (INIS)

Roussin, R.W.; Drischler, J.D.; Marable, J.H.

1980-01-01

In recent years multigroup sensitivity profiles and covariance matrices have been added to the Radiation Shielding Information Center's Data Library Collection (DLC). Sensitivity profiles are available in a single package. DLC-45/SENPRO, and covariance matrices are found in two packages, DLC-44/COVERX and DLC-77/COVERV. The contents of these packages are described and their availability is discussed

Polymeric reaction of polymer-monomer system for pressure sensitive adhesives by low energy electron beam

International Nuclear Information System (INIS)

Takiguchi, R.; Uryu, T.

1985-01-01

Application of low-energy electron beam to non-solvent type pressure sensitive adhesives is investigated. The adhesive properties such as peel strength and holding time (dead-load strength) were closely related to the reaction of acrylate polymer-monomer systems. The reaction behavior is elucidated by combining the measurement of gel fraction, infrared spectrum of gel, and the molecular weight distribution detected by gel permeation chromatography. It was important for the production of pressure sensitive adhesives by electron beam that the adhesive with high peel strength and long holding time is composed of a proper combination of three factors, that is, about 35% gel fraction, 25% monomer units in gel, and 15% graft efficiency by irradiating the polymer-monomer system containing low molecular weight poly (butyl acrylate). (author)

Radiochromic film sensitivity calibrations using ion beams from a Pelletron accelerator

Science.gov (United States)

Filkins, T. M.; Steidle, Jessica; Ward, R. J.; Freeman, C. G.; Padalino, S. J.; Regan, S. P.; Sangster, T. C.

2015-11-01

Radiochromic film (RCF) is a transparent detector film that permanently changes color following exposure to ionizing radiation. The optical density of the film increases with increasing absorbed dose. RCF is convenient to use because it requires no chemical processing and can be scanned using commercially available document scanners. RCF is used frequently in medical applications, but is also used in a variety of diagnostics in high energy density physics. The film consists of a single or double layer of radiation-sensitive organic microcrystal monomers placed onto a polyester backing. GafchromicTM manufactures a large number of different types of RCF, and new types of film frequently replace older products. In this study, the sensitivity of several types of RCF to ion beams of different energies was measured. Ion beams produced by the SUNY Geneseo 1.7 MV Pelletron accelerator were directed into a target chamber where they scattered off of a gold foil. A sample of RCF was exposed to the scattered ions. The fluence of incident particles on the film was measured using a surface barrier detector. Results of these calibrations will be presented. This work was funded in part by a grant from the DOE through the Laboratory for Laser Energetics.

Beam Profile Measurement of 300 kV Ion Source Test Stand for 1 MV Electrostatic Accelerator

International Nuclear Information System (INIS)

Park, Sae-Hoon; Kim, Yu-Seok; Kim, Dae-Il; Kwon, Hyeok-Jung; Cho, Yong-Sub

2015-01-01

In this paper, RF ion source, test stand of the ion source and its test results are presented. Beam profile was measured at the downstream from the accelerating tube and at the beam dump by using BPM and wire scanner. The RF ion source of the test stand is verified by measuring the total beam current with a faraday cup in the chamber. The KOMAC (KOrea Multi-purpose Accelerator Complex) has been developing a 300 kV ion source test stand for a 1 MV electrostatic accelerator. An ion source and accelerating tube will be installed in a high pressure vessel. The ion source in a high pressure vessel requires high reliability. To confirm the stable operation of the ion source, a test stand was proposed and developed. The ion source will be tested at the test stand to verify its long-term operation conditions. The test stand consists of a 300 kV high voltage terminal, a battery for the ion source power, a 60 Hz inverter, a 200 MHz RF power, a 5 kV extraction power supply, a 300 kV accelerating tube, and a vacuum system. The beam profile monitor was installed at the downstream from the accelerating tube. Wire scanner and faraday-cup was installed at the end of the chamber

Beam Profile Measurement of 300 kV Ion Source Test Stand for 1 MV Electrostatic Accelerator

Energy Technology Data Exchange (ETDEWEB)

Park, Sae-Hoon; Kim, Yu-Seok [Dongguk University, Gyeonju (Korea, Republic of); Kim, Dae-Il; Kwon, Hyeok-Jung; Cho, Yong-Sub [Korea Multipurpose Accelerator Complex, Gyeongju (Korea, Republic of)

2015-10-15

In this paper, RF ion source, test stand of the ion source and its test results are presented. Beam profile was measured at the downstream from the accelerating tube and at the beam dump by using BPM and wire scanner. The RF ion source of the test stand is verified by measuring the total beam current with a faraday cup in the chamber. The KOMAC (KOrea Multi-purpose Accelerator Complex) has been developing a 300 kV ion source test stand for a 1 MV electrostatic accelerator. An ion source and accelerating tube will be installed in a high pressure vessel. The ion source in a high pressure vessel requires high reliability. To confirm the stable operation of the ion source, a test stand was proposed and developed. The ion source will be tested at the test stand to verify its long-term operation conditions. The test stand consists of a 300 kV high voltage terminal, a battery for the ion source power, a 60 Hz inverter, a 200 MHz RF power, a 5 kV extraction power supply, a 300 kV accelerating tube, and a vacuum system. The beam profile monitor was installed at the downstream from the accelerating tube. Wire scanner and faraday-cup was installed at the end of the chamber.

X-ray beam-shaping via deformable mirrors: Analytical computation of the required mirror profile

International Nuclear Information System (INIS)

Spiga, Daniele; Raimondi, Lorenzo; Svetina, Cristian; Zangrando, Marco

2013-01-01

X-ray mirrors with high focusing performances are in use in both mirror modules for X-ray telescopes and in synchrotron and FEL (Free Electron Laser) beamlines. A degradation of the focus sharpness arises in general from geometrical deformations and surface roughness, the former usually described by geometrical optics and the latter by physical optics. In general, technological developments are aimed at a very tight focusing, which requires the mirror profile to comply with the nominal shape as much as possible and to keep the roughness at a negligible level. However, a deliberate deformation of the mirror can be made to endow the focus with a desired size and distribution, via piezo actuators as done at the EIS-TIMEX beamline of FERMI@Elettra. The resulting profile can be characterized with a Long Trace Profilometer and correlated with the expected optical quality via a wavefront propagation code. However, if the roughness contribution can be neglected, the computation can be performed via a ray-tracing routine, and, under opportune assumptions, the focal spot profile (the Point Spread Function, PSF) can even be predicted analytically. The advantage of this approach is that the analytical relation can be reversed; i.e., from the desired PSF the required mirror profile can be computed easily, thereby avoiding the use of complex and time-consuming numerical codes. The method can also be suited in the case of spatially inhomogeneous beam intensities, as commonly experienced at synchrotrons and FELs. In this work we expose the analytical method and the application to the beam shaping problem

Dynamic wedge, electron energy and beam profile Q.A. using an ionization chamber linear array

International Nuclear Information System (INIS)

Kenny, M.B.; Todd, S.P.

1996-01-01

Since the introduction of multi-modal linacs the quality assurance workload of a Physical Sciences department has increased dramatically. The advent of dynamic wedges has further complicated matters because of the need to invent accurate methods to perform Q.A. in a reasonable time. We have been using an ionization chamber linear array, the Thebes 7000 TM by Victoreen, Inc., for some years to measure X-ray and electron beam profiles. Two years ago we developed software to perform Q.A. on our dynamic wedges using the array and more recently included a routine to check electron beam energies using the method described by Rosenow, U.F. et al., Med. Phys. 18(1) 19-25. The integrated beam and profile management system has enabled us to maintain a comprehensive quality assurance programme on all our linaccs. Both our efficiency and accuracy have increased to the point where we are able to keep up with the greater number of tests required without an increase in staff or hours spent in quality assurance. In changing the processor from the Z80 of the Thebes console to the 486 of the PC we have also noticed a marked increase in the calibration stability of the array. (author)

Broad beam ion sources and some surface processes

International Nuclear Information System (INIS)

Neumann, H.; Scholze, F.; Tarz, M.; Schindler, A.; Wiese, R.; Nestler, M.; Blum, T.

2005-01-01

Modern broad-beam multi-aperture ion sources are widely used in material and surface technology applications. Customizing the generated ion beam properties (i. e. the ion current density profile) for specific demands of the application is a main challenge in the improvement of the ion beam technologies. First we introduce ion sources based on different plasma excitation principles shortly. An overview of source plasma and ion beam measurement methods deliver input data for modelling methods. This beam profile modelling using numerical trajectory codes and the validation of the results by Faraday cup measurements as a basis for ion beam profile design are described. Furthermore possibilities for ex situ and in situ beam profile control are demonstrated, like a special method for in situ control of a linear ion source beam profile, a grid modification for circular beam profile design and a cluster principle for broad beam sources. By means of these methods, the beam shape may be adapted to specific technological demands. Examples of broad beam source application in ion beam figuring of optical surfaces, modification of stainless steel, photo voltaic processes and deposition of EUVL-multilayer stacks are finally presented. (Author)

Optimizing the e-beam profile of a single carbon nanotube field emission device for electric propulsion systems

Directory of Open Access Journals (Sweden)

Juliano Fujioka Mologni

2010-04-01

Full Text Available Preliminary studies on field emission (FE arrays comprised of carbon nanotubes (CNT as an electron source for electric propulsion system show remarkably promising results. Design parameters for a carbon nanotube (CNT field-emission device operating on triode configuration were numerically simulated and optimized in order to enhance the e-beam focusing quality. An additional focus gate (FG was integrated to the device to control the profile of the emitted e-beam. An axisymmetric finite element model was developed to calculate the electric field distribution on the vacuum region and a modified Fowler-Nordheim (FN equation was used to evaluate the current density emission and the effective emitter area. Afterward, a FE simulation was employed in order to calculate the trajectory of the emitted electrons and define the electron-optical properties of the e-beam. The integration of the FG was fully investigated via computational intelligence techniques. The best performance device according to our simulations presents a collimated e-beam profile that suits well for field emission displays, magnetic field detection and electron microscopy. The automated computational design tool presented in this study strongly benefits the robust design of integrated electron-optical systems for vacuum field emission applications, including electrodynamic tethering and electric propulsion systems.

Characterisation of flattening filter free (FFF) beam properties for initial beam set-up and routine QA, independent of flattened beams

Science.gov (United States)

Paynter, D.; Weston, S. J.; Cosgrove, V. P.; Thwaites, D. I.

2018-01-01

Flattening filter free (FFF) beams have reached widespread use for clinical treatment deliveries. The usual methods for FFF beam characterisation for their quality assurance (QA) require the use of associated conventional flattened beams (cFF). Methods for QA of FFF without the need to use associated cFF beams are presented and evaluated against current methods for both FFF and cFF beams. Inflection point normalisation is evaluated against conventional methods for the determination of field size and penumbra for field sizes from 3 cm  ×  3 cm to 40 cm  ×  40cm at depths from dmax to 20 cm in water for matched and unmatched FFF beams and for cFF beams. A method for measuring symmetry in the cross plane direction is suggested and evaluated as FFF beams are insensitive to symmetry changes in this direction. Methods for characterising beam energy are evaluated and the impact of beam energy on profile shape compared to that of cFF beams. In-plane symmetry can be measured, as can cFF beams, using observed changes in profile, whereas cross-plane symmetry can be measured by acquiring profiles at collimator angles 0 and 180. Beam energy and ‘unflatness’ can be measured as with cFF beams from observed shifts in profile with changing beam energy. Normalising the inflection points of FFF beams to 55% results in an equivalent penumbra and field size measurement within 0.5 mm of conventional methods with the exception of 40 cm  ×  40 cm fields at a depth of 20 cm. New proposed methods are presented that make it possible to independently carry out set up and QA measurements on beam energy, flatness, symmetry and field size of an FFF beam without the need to reference to an equivalent flattened beam of the same energy. The methods proposed can also be used to carry out this QA for flattened beams, resulting in universal definitions and methods for MV beams. This is presented for beams produced by an Elekta linear accelerator, but is

Apparatus for tomography in which signal profiles gathered from divergent radiation can be reconstructed in signal profiles, each corresponding with a beam of parallel rays

International Nuclear Information System (INIS)

1976-01-01

A tomograph which is capable of gathering divergent radiations and reconstruct them in signal profiles or images each corresponding with a beam of parallel rays is discussed which may eliminate the interfering point dispersion function which normally occurs

Beam radiation curing of adhesives for flocking on heat-sensitive substrates

International Nuclear Information System (INIS)

Nablo, S.V.; Fussa, A.D.

1979-01-01

A process is described for curing the adhesive used to hold flock fiber material to a heat-sensitive substrate consisting of temperature-sensitive plastic, natural fibers, wood, paper, or paper-foil laminates. An electron-curable adhesive layer (acrylic, epoxy, epoxy esters, acrylic latex, or urethane) a few mils thick is applied to the substrate and a layer of texturing material is attached to the adhesive layer with fibers substantially perpendicular to the layer. The assembly of substrate and adhesively secured material is passed at a rate of about 20 to 80 meters per minute under an unscanned electron curtain beam which possesses an energy of 150 keV +- 30 percent and delivers an electron dose of 2 megarads +- 50 percent to the adhesive layer. (LL)

Wavelength-independent laser beam shaping

CSIR Research Space (South Africa)

Degama, MP

2010-07-01

Full Text Available This paper presents a beam shaping device namely, a Diffractive Optical Element (DOE), which is used to change a beam having a Gaussian intensity profile into a beam with a uniform intensity profile. The DOE used in this work was fabricated from Zn...

Sensitivity and offset calibration for the beam position monitors at the Advanced Photon Source

International Nuclear Information System (INIS)

Chung, Y.; Barr, D.; Decker, G.; Evans, K. Jr.; Kahana, E.

1995-01-01

The beam position monitors (BPMs) play a critically important role in commissioning and operation of accelerators. Accurate determination of the offsets relative to the magnetic axis and sensitivities of individual BPMs is thus needed. We will describe in this paper the schemes for calibrating all of the 360 BPMs for sensitivity and offset in the 7-GeV Advanced Photon Source (APS) storage ring and the results. For the sensitivity calibration, a 2-dimensional map of the BPM response in the aluminum vacuum chamber is obtained theoretically, which is combined with the measured nonlinear response of the BPM electronics. A set of 2-dimensional polynomial coefficients is then obtained to approximate the result analytically. The offset calibration of the BPMs is done relative to the magnetic axis of the quadrupoles using the beam. This avoids the problem arising from various mechanical sources as well as the offset in the processing electronics. The measurement results for the resolution and long-term drift of the BPM electronics shows 0.06-μm/√Hz resolution and 2-μm/hr drift over a period of 1.5 hrs

Practical use of a plastic scintillator for quality assurance of electron beam therapy.

Science.gov (United States)

Yogo, Katsunori; Tatsuno, Yuya; Tsuneda, Masato; Aono, Yuki; Mochizuki, Daiki; Fujisawa, Yoshiki; Matsushita, Akihiro; Ishigami, Minoru; Ishiyama, Hiromichi; Hayakawa, Kazushige

2017-06-07

Quality assurance (QA) of clinical electron beams is essential for performing accurate and safe radiation therapy. However, with advances in radiation therapy, QA has become increasingly labor-intensive and time-consuming. In this paper, we propose a tissue-equivalent plastic scintillator for quick and easy QA of clinical electron beams. The proposed tool comprises a plastic scintillator plate and a charge-coupled device camera that enable the scintillation light by electron beams to be recorded with high sensitivity and high spatial resolution. Further, the Cerenkov image is directly subtracted from the scintillation image to discriminate Cerenkov emissions and accurately measure the dose profiles of electron beams with high spatial resolution. Compared with conventional methods, discrepancies in the depth profile improved from 7% to 2% in the buildup region via subtractive corrections. Further, the output brightness showed good linearity with dose, good reproducibility (deviations below 1%), and dose rate independence (within 0.5%). The depth of 50% dose measured with the tool, an index of electron beam quality, was within  ±0.5 mm of that obtained with an ionization chamber. Lateral brightness profiles agreed with the lateral dose profiles to within 4% and no significant improvement was obtained using Cerenkov corrections. Field size agreed to within 0.5 mm with those obtained with ionization chamber. For clinical QA of electron boost treatment, a disk scintillator that mimics the shape of a patient's breast is applied. The brightness distribution and dose, calculated using a treatment planning system, was generally acceptable for clinical use, except in limited zones. Overall, the proposed plastic scintillator plate tool efficiently performs QA for electron beam therapy and enables simultaneous verification of output constancy, beam quality, depth, and lateral dose profiles during monthly QAs at lower doses of irradiation (small monitor units, MUs).

Beam line design for a low energy electron beam

International Nuclear Information System (INIS)

Arvind Kumar; Mahadevan, S.

2002-01-01

The design of a beam line for transport of a 70 keV electron beam from a thermionic gun to the Plane Wave Transformer (PWT) linac incorporating two solenoid magnets, a beam profile monitor and drift sections is presented. We used beam dynamics codes EGUN, PARMELA and compare simulated results with analytical calculations. (author)

How Is Interreligious Sensitivity Related to Finnish Pupils' Religiousness Profiles?

Science.gov (United States)

Kuusisto, Elina; Kuusisto, Arniika; Kallioniemi, Arto

2016-01-01

This paper examines, through a non-probability sample of 451 Finnish lower secondary-school pupils belonging to the 15- to 16-year-old age group, how interreligious sensitivity is related to religiousness profiles of Finnish youth. The data were gathered in two geographical locations: Helsinki, Finland's capital, and a smaller municipality in the…

Ion-beam nanopatterning: experimental results with chemically-assisted beam

Science.gov (United States)

Pochon, Sebastien C. R.

2018-03-01

The need for forming gratings (for example used in VR headsets) in materials such as SiO2 has seen a recent surge in the use of Ion beam etching techniques. However, when using an argon-only beam, the selectivity is limited as it is a physical process. Typically, gases such as CHF3, SF6, O2 and Cl2 can be added to argon in order to increase selectivity; depending on where the gas is injected, the process is known as Reactive Ion Beam Etching (RIBE) or Chemically Assisted Ion Beam Etching (CAIBE). The substrate holder can rotate in order to provide an axisymmetric etch rate profile. It can also be tilted over a range of angles to the beam direction. This enables control over the sidewall profile as well as radial uniformity optimisation. Ion beam directionality in conjunction with variable incident beam angle via platen angle setting enables profile control and feature shaping during nanopatterning. These hardware features unique to the Ion Beam etching methods can be used to create angled etch features. The CAIBE technique is also well suited to laser diode facet etch (for optoelectronic devices); these typically use III-V materials like InP. Here, we report on materials such as SiO2 etched without rotation and at a fixed platen angle allowing the formation of gratings and InP etched at a fixed angle with rotation allowing the formation of nanopillars and laser facets.

Application of PLC technology in measurement of beam profile on 100 MeV accelerator

International Nuclear Information System (INIS)

Yu Luyang; Chinese Academy of Sciences, Beijing; Chen Yongzhong; Chen Yongzhong; Liu Dekang; Chinese Academy of Sciences, Beijing

2005-01-01

A comprehensive introduction is given to the real-time measuring method, which is based on the Programmable Logic Controller (PLC) technology and can measure intensity and profile of the beam by a scintillator screen. The whole system has many advantages, such as good reliability, high precision, intuitional measurement, etc. due to the use of the PLC and Labview software. (authors)

Developments in non-destructive beam diagnostics

International Nuclear Information System (INIS)

Fraser, J.S.

1981-01-01

With the large average beam currents being achieved in accelerators and storage rings, there is an increasing need for non-destructive beam diagnostic devices. For continuous beams, position monitors of the capacitive pick-up type are replaced by resonant devices that respond to the transverse displacement of the beam centroid. Bunch length monitors of the SLAC type using resonant cavities operating in the TM 010 mode can be used for continuous beams. The more detailed information derivable from beam profile scanners requires development of improved non-destructive devices. Profile monitors which scan the visible light produced by high current beams may be more reliable than ones using the residual ionization if the light intensity from gas molecules following nonionizing collisions with beam particles gives a measure of the beam current density independent of the local electron density. The intense Balmer series lines from neutral hydrogen beams have been used successfully to measure beam profiles. At CRNL and at LASL, beam light profile monitors are being developed for high average current accelerators. Three or more projections will be recorded to allow tomographic reconstruction of the two-dimensional beam current density. Light detection is either by intensified Reticons or ISIT vidicons. The use of three or more beam light monitors on a beam transport line will also permit estimates of the transverse emittance to be made through the reconstruction technique

Impedance-based analysis and study of phase sensitivity in slow-wave two-beam accelerators

International Nuclear Information System (INIS)

Wurtele, J.S.; Whittum, D.H.; Sessler, A.M.

1992-06-01

This paper presents a new formalism which makes the analysis and understanding of both the relativistic klystron (RK) and the standing-wave free-electron laser (SWFEL) two-beam accelerator (TBA) available to a wide audience of accelerator physicists. A ''coupling impedance'' for both the RK and SWFEWL is introduced, which can include realistic cavity features, such as beam and vacuum ports, in a simple manner. The RK and SWFEL macroparticle equations, which govern the energy and phase evolution of successive bunches in the beam, are of identical form, differing only by multiplicative factors. Expressions are derived for the phase and amplitude sensitivities of the TBA schemes to errors (shot-to-shot jitter) in current and energy. The analysis allows, for the first time, relative comparisons of the RK and the SWFEL TBAs

Calibration of the OPAL jet chamber with UV laser beams. Measurement of the beam position with position-sensitive silicon diodes (PSD)

International Nuclear Information System (INIS)

Koch, J.

1990-03-01

The OPAL jet chamber is calibrated with tracks produced by UV laser beams. Lateral effect diodes are used for monitoring the laser beam location in the detector. These position sensitive detectors locate the point of impact in two dimensions by the charge division method. Measurements on several diodes were carried out in order to calibrate these devices and to investigate to observed pin-cushion distortion. Using the telegraphers equation suitable expressions were obtained for describing the observed behaviour. It was shown that the magnetic field of OPAL as well as the UV laser wavelength and puls duration had no influence on the position information. (orig.)

Enhanced sensitivity in a butterfly gyroscope with a hexagonal oblique beam

Energy Technology Data Exchange (ETDEWEB)

Xiao, Dingbang; Cao, Shijie; Hou, Zhanqiang, E-mail: houzhanqiang@nudt.edu.cn; Chen, Zhihua; Wang, Xinghua; Wu, Xuezhong [College of Mechatronics Engineering and Automation, National University of Defense Technology, Changsha, Hunan, 410073 (China)

2015-04-15

A new approach to improve the performance of a butterfly gyroscope is developed. The methodology provides a simple way to improve the gyroscope’s sensitivity and stability, by reducing the resonant frequency mismatch between the drive and sense modes. This method was verified by simulations and theoretical analysis. The size of the hexagonal section oblique beam is the major factor that influences the resonant frequency mismatch. A prototype, which has the appropriately sized oblique beam, was fabricated using precise, time-controlled multilayer pre-buried masks. The performance of this prototype was compared with a non-tuned gyroscope. The scale factor of the prototype reaches 30.13 mV/ °/s, which is 15 times larger than that obtained from the non-tuned gyroscope. The bias stability of the prototype is 0.8 °/h, which is better than the 5.2 °/h of the non-tuned devices.

Ultrasonic Beam Propagation in Highly Anisotropic Materials Simulated by Multi-Gaussian Beams

International Nuclear Information System (INIS)

Jeong, Hyun Jo; Schmerr, Lester W.

2007-01-01

The necessity of nondestructively inspecting fiber-reinforced composites, austenitic steels, and other inherently anisotropic materials has stimulated considerable interest in developing beam models for anisotropic media. The properties of slowness surface play key role in the beam models based on the paraxial approximation. In this paper, we apply a modular multi-Gaussian beam (MMGB) model to study the effects of material anisotropy on ultrasonic beam profile. It is shown that the anisotropic effects of beam skew and excess beam divergence enter into the MMGB model through parameters defining the slope and curvature of the slowness surface. The overall beam profile is found when the quasi longitudinal (qL) beam propagates in the symmetry plane of a transversely isotropic gr/ep composite. Simulation results are presented to illustrate the effects of these parameters on ultrasonic beam diffraction and beam skew. The MMGB calculations are also checked by comparing the anisotropy factor and beam skew angle with other analytical solutions

An investigation of process sensitivity for electron beam evaporation of beryllium

International Nuclear Information System (INIS)

Egert, C.M.; Schmoyer, D.D.; Nordin, C.W.; Berry, A.

1991-01-01

This paper reports on the process sensitivity of a beryllium coating process investigated using a statistical design of experiments approach. Process sensitivity is a measure of the variation in a given quality characteristic of the coating as a function of the evaporation process parameters. Manufacturing processes which maximize quality while simultaneously minimizing variability are most desirable. Three evaporation process parameters were included in this study: deposition rate, substrate temperature, and run time. A central composite experimental design employing a total of 18 coating runs was used to produce beryllium coatings on aluminum, silicon, fused silica, and beryllium substrates. The quality of the resulting coatings was characterized by scanning electron microscopy, IR spectrophotometry, stylus profilometry, and weight gain (thickness). Analysis of these results allowed the development of functional relationship between the quality characteristics (thickness, reflectance, etc.) and the evaporation process parameters. Process sensitivity for each response was then determined by calculating the gradient of each quality characteristic with respect to all three process parameters. Three dimensional plots were developed of the quality characteristic and its process sensitivity as a function of process parameters. Both quality characteristic and process sensitivity plots will be presented and discussed. For many of the quality characteristics, temperature during deposition was found to be the most sensitive process parameter for the beryllium c-beam evaporation process

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

Directory of Open Access Journals (Sweden)

Shimozuma T.

2015-01-01

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

Measurement of surface temperature profiles on liquid uranium metal during electron beam evaporation

Energy Technology Data Exchange (ETDEWEB)

Ohba, Hironori; Shibata, Takemasa [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

1998-11-01

Surface temperature distributions of liquid uranium in a water-cooled copper crucible during electron beam evaporation were measured. Evaporation surface was imaged by a lens through a band-path filter (650{+-}5 nm) and a double mirror system on a charge coupled device (CCD) camera. The video signals of the recorded image were connected to an image processor and converted to two-dimensional spectral radiance profiles. The surface temperatures were obtained from the spectral radiation intensity ratio of the evaporation surface and a freezing point of uranium and/or a reference light source using Planck`s law of radiation. The maximum temperature exceeded 3000 K and had saturation tendency with increasing electron beam input. The measured surface temperatures agreed with those estimated from deposition rates and data of saturated vapor pressure of uranium. (author)

Small field electron beam dosimetry using MOSFET detector.

Science.gov (United States)

Amin, Md Nurul; Heaton, Robert; Norrlinger, Bern; Islam, Mohammad K

2010-10-04

The dosimetry of very small electron fields can be challenging due to relative shifts in percent depth-dose curves, including the location of dmax, and lack of lateral electronic equilibrium in an ion chamber when placed in the beam. Conventionally a small parallel plate chamber or film is utilized to perform small field electron beam dosimetry. Since modern radiotherapy departments are becoming filmless in favor of electronic imaging, an alternate and readily available clinical dosimeter needs to be explored. We have studied the performance of MOSFET as a relative dosimeter in small field electron beams. The reproducibility, linearity and sensitivity of a high-sensitivity microMOSFET were investigated for clinical electron beams. In addition, the percent depth doses, output factors and profiles have been measured in a water tank with MOSFET and compared with those measured by an ion chamber for a range of field sizes from 1 cm diameter to 10 cm × 10 cm for 6, 12, 16 and 20 MeV beams. Similar comparative measurements were also per-formed with MOSFET and films in solid water phantom. The MOSFET sensitivity was found to be practically constant over the range of field sizes investigated. The dose response was found to be linear and reproducible (within ± 1% for 100 cGy). An excellent agreement was observed among the central axis depth dose curves measured using MOSFET, film and ion chamber. The output factors measured with MOSFET for small fields agreed to within 3% with those measured by film dosimetry. Overall results indicate that MOSFET can be utilized to perform dosimetry for small field electron beam.

Accurate Profile Measurement of the low Intensity Secondary Beams in the CERN Experimental Areas

CERN Document Server

AUTHOR|(CDS)2084531; Tranquille, Gerard

2018-02-23

The CERN accelerators deliver a wide spectrum of secondary beams to the Experimental Areas. These beams are composed of hadrons, leptons, and heavy ions that can vary greatly in momentum (1 GeV/c to 400 GeV/c) and intensity (10^2 to 10^8 particles per second). The profile, position, and intensity of these beams are measured utilising particle detectors. However, the current systems show several problems that limit the quality of this kind of monitoring. The aim of this doctoral thesis is to investigate the best detector technology that could replace the existing monitors and build a first prototype of it. A review of the existing detection techniques has led to the choice of Scintillating Fibres (SciFi) read-out with Silicon Photomultipliers (SiPM). This detection technology has the potential to perform better in terms of material budget, range of intensities measured, and active area size. In addition, it has particle counting capabilities, which could extend its application to momentum spectrometry or Time...

Astigmatism-free high-brightness 1060 nm edge-emitting lasers with narrow circular beam profile.

Science.gov (United States)

Miah, Md Jarez; Kalosha, Vladimir P; Bimberg, Dieter; Pohl, Johannes; Weyers, Markus

2016-12-26

1060 nm high-brightness vertical broad-area edge-emitting lasers providing anastigmatic high optical power into a narrow circular beam profile are demonstrated. Ridge-waveguide (RW) lasers yield record 2.2 W single-transverse mode power in the 1060-nm wavelength range under continuous-wave (cw) operation at room temperature with excellent beam quality factor M2 ≤ 2. Independent of operating current the astigmatism is only 2.5 µm. 3 mm long broad-area (BA) lasers produce a θvert as narrow as 9° full width at half maximum, which agrees well with our simulation results, being insensitive to drive current. 5 mm long BA lasers deliver highest ever reported cw 12 W multimode output power among lasers showing θvert <10° in the 1060-nm wavelength range. The emitted laser beams from both RW and BA lasers show a perfect circular shape with ≤10° divergence angle at record 2.1 W and 4.2 W cw-mode output power, respectively.

Control of quasi-monoenergetic electron beams from laser-plasma accelerators with adjustable shock density profile

Science.gov (United States)

Tsai, Hai-En; Swanson, Kelly K.; Barber, Sam K.; Lehe, Remi; Mao, Hann-Shin; Mittelberger, Daniel E.; Steinke, Sven; Nakamura, Kei; van Tilborg, Jeroen; Schroeder, Carl; Esarey, Eric; Geddes, Cameron G. R.; Leemans, Wim

2018-04-01

The injection physics in a shock-induced density down-ramp injector was characterized, demonstrating precise control of a laser-plasma accelerator (LPA). Using a jet-blade assembly, experiments systematically varied the shock injector profile, including shock angle, shock position, up-ramp width, and acceleration length. Our work demonstrates that beam energy, energy spread, and pointing can be controlled by adjusting these parameters. As a result, an electron beam that was highly tunable from 25 to 300 MeV with 8% energy spread (ΔEFWHM/E), 1.5 mrad divergence, and 0.35 mrad pointing fluctuation was produced. Particle-in-cell simulation characterized how variation in the shock angle and up-ramp width impacted the injection process. This highly controllable LPA represents a suitable, compact electron beam source for LPA applications such as Thomson sources and free-electron lasers.

The mouse beam walking assay offers improved sensitivity over the mouse rotarod in determining motor coordination deficits induced by benzodiazepines.

Science.gov (United States)

Stanley, Joanna L; Lincoln, Rachael J; Brown, Terry A; McDonald, Louise M; Dawson, Gerard R; Reynolds, David S

2005-05-01

The mouse rotarod test of motor coordination/sedation is commonly used to predict clinical sedation caused by novel drugs. However, past experience suggests that it lacks the desired degree of sensitivity to be predictive of effects in humans. For example, the benzodiazepine, bretazenil, showed little impairment of mouse rotarod performance, but marked sedation in humans. The aim of the present study was to assess whether the mouse beam walking assay demonstrates: (i) an increased sensitivity over the rotarod and (ii) an increased ability to predict clinically sedative doses of benzodiazepines. The study compared the effects of the full benzodiazepine agonists, diazepam and lorazepam, and the partial agonist, bretazenil, on the mouse rotarod and beam walking assays. Diazepam and lorazepam significantly impaired rotarod performance, although relatively high GABA-A receptor occupancy was required (72% and 93%, respectively), whereas beam walking performance was significantly affected at approximately 30% receptor occupancy. Bretazenil produced significant deficits at 90% and 53% receptor occupancy on the rotarod and beam walking assays, respectively. The results suggest that the mouse beam walking assay is a more sensitive tool for determining benzodiazepine-induced motor coordination deficits than the rotarod. Furthermore, the GABA-A receptor occupancy values at which significant deficits were determined in the beam walking assay are comparable with those observed in clinical positron emission tomography studies using sedative doses of benzodiazepines. These data suggest that the beam walking assay may be able to more accurately predict the clinically sedative doses of novel benzodiazepine-like drugs.

[Effect of oral administration of ascorbic acid on insulin sensitivity and lipid profile in obese individuals].

Science.gov (United States)

Martínez-Abundis, E; Pascoe-González, S; González-Ortiz, M; Mora-Martínez, J M; Cabrera-Pivaral, C E

2001-01-01

The aim of this study was to identify the effect of an oral ascorbic acid (AA) supplement on lipid profile and insulin sensitivity in obese people. A randomized double-blind clinical trial placebo controlled was performed in 16 obese male volunteers [body mass index (BMI) 30-40 kg/m2]. Eight received orally 1 g of AA daily for four weeks and the other eight volunteers received placebo by the same scheme and period of time. Before and after the pharmacological intervention were measured total cholesterol, high-density-lipoprotein (HDL) cholesterol, triglycerides, glucose, creatinine and uric acid. Low-density-lipoprotein (LDL) cholesterol and very-low-density-lipoprotein (VLDL) triglycerides were calculated using formulas. In order to assess insulin sensitivity before and after the intervention, the steady-state glucose (SSG) was calculated from the insulin suppression test modified with octreotide. There were not significant differences in clinical characteristics between both groups. Basal metabolic profile and SSG were similar between both groups. There were not significant differences in both groups between before and after the intervention in metabolic profile and insulin sensitivity. AA did not modify the lipid profile nor insulin sensitivity in the group of obese people studied.

Nutrient Profiles and Volatile Odorous Compounds of Raw Milk After Exposure to Electron Beam Pasteurizing Doses.

Science.gov (United States)

Ward, Lindsay R; Kerth, Chris R; Pillai, Suresh D

2017-07-01

Raw milk is known to contain relatively high numbers of microorganisms, some of which include microbial pathogens. Electron beam (eBeam) processing is a nonthermal pasteurization food processing technology. The underlying hypothesis was that eBeam processing will not negatively influence the composition, nutrient content, and aroma profile of raw milk. Raw milk samples were exposed to eBeam doses of 1 and 2 kGy, since our studies had shown that 2 kGy is suitable for raw milk pasteurization. The untreated and eBeam-treated raw milk samples were analyzed to detect changes in lactose, vitamin B 2 , vitamin B 12 , and calcium concentrations. The possible breakdown of casein and whey proteins and lipid oxidation were investigated along with the formation of volatile aroma compounds. Even though vitamin B 2 showed a 31.6% decrease in concentration, the B 2 content in eBeam-pasteurized raw milk met all USDA nutritional guidelines. Even though there were no indications of lipid oxidation after the 2.0-kGy eBeam treatment, there was lipid oxidation (58%) after 7 d of refrigerated storage. However, based on the GC-olfactory analysis, the lipid oxidation did not necessarily result in the development of a wide variety of off-odors. © 2017 Institute of Food Technologists®.

Latex allergy: new insights to explain different sensitization profiles in different risk groups.

Science.gov (United States)

Peixinho, C; Tavares-Ratado, P; Tomás, M R; Taborda-Barata, L; Tomaz, C T

2008-07-01

Differences in latex allergen sensitization profiles have been described between children subjected to repetitive surgical interventions and health care workers (HCW). 'Major' allergens for patients with spina bifida are Hev b 1, 3 and 7, while for HCW, 'major' allergens are Hev b 2, 5, 6.01 and 13. The reason for these differential sensitization profiles is currently unknown. To investigate latex allergen profiles on internal and external surfaces of natural rubber latex gloves. Eighty-two samples of commonly used surgical gloves (41 glove brands) were used for analysis. Specific allergen levels of Hev b 1, 3, 5 and 6.02 on both surfaces of the gloves were quantified using an enzyme immunometric assay, a FITkit (FIT Biotech, Tampere, Finland). Differences in allergen levels were observed between internal and external surfaces of all glove types. Concentrations of Hev b 1 and Hev b 3 were significantly higher on external surfaces, while internal surfaces had higher allergen levels of Hev b 5 and Hev b 6.02. Analysis of surgical and examination gloves, powdered and nonpowdered gloves also showed that the content of Hev b 5 and Hev b 6.02 was significantly higher on internal surfaces while that of Hev b 1 and Hev b 3 was higher on external surfaces. Our study showed different allergen profiles on internal and external surfaces of natural rubber latex gloves. These results may suggest a relationship between latex allergen localization and sensitization routes in different risk groups.

Edge electron density profiles and fluctuations measured by two-dimensional beam emission spectroscopy in the KSTAR

Energy Technology Data Exchange (ETDEWEB)

Nam, Y. U., E-mail: yunam@nfri.re.kr; Wi, H. M. [National Fusion Research Institute, Daejeon (Korea, Republic of); Zoletnik, S.; Lampert, M. [Wigner RCP Institute for Particle and Nuclear Physics, Budapest (Hungary); Kovácsik, Ákos [Institute of Nuclear Techniques, Budapest Technical University, Budapest (Hungary)

2014-11-15

Beam emission spectroscopy (BES) system in Korea Superconducting Tokamak Advanced Research (KSTAR) has recently been upgraded. The background intensity was reduced from 30% to 2% by suppressing the stray lights. This allows acquisition of the relative electron density profiles on the plasma edge without background subtraction from the beam power modulation signals. The KSTAR BES system has its spatial resolution of 1 cm, the temporal resolution of 2 MHz, and a total 32 channel (8 radial × 4 poloidal) avalanche photo diode array. Most measurements were done on the plasma edge, r/a ∼ 0.9, with 8 cm radial measurement width that covers the pedestal range. High speed density profile measurements reveal temporal behaviors of fast transient events, such as the precursors of edge localized modes and the transitions between confinement modes. Low background level also allows analysis of the edge density fluctuation patterns with reduced background fluctuations. Propagation of the density structures can be investigated by comparing the phase delays between the spatially distributed channels.

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

Science.gov (United States)

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.

Imagescope to photodiode beam-profile imaging system

International Nuclear Information System (INIS)

Chamberlin, D.D.; Hollabaugh, J.S.; Stump, C.J. Jr.

1983-01-01

Transverse beam-distribution measurements of high-current cw accelerators must be obtained from noninterceptive sensors. For the 100-mA H 2 or D beam of the Fusion Materials Irradiation Tst (FMIT) accelerator, these transverse properties may be obtained by detecting the visible radiation resulting from beam interactions with residual gas. A system of mirrors, intensified TV cameras, digitizers, and topographic reconstruction codes has been reported previously. This report describes a new technique for sensing and digitizing the light projected transversely from the beam of the FMIT accelerator at Los Alamos National Laboratory

Cardiac single-photon emission-computed tomography using combined cone-beam/fan-beam collimation

International Nuclear Information System (INIS)

Gullberg, Grant T.; Zeng, Gengsheng L.

2004-01-01

The objective of this work is to increase system sensitivity in cardiac single-photon emission-computed tomography (SPECT) studies without increasing patient imaging time. For imaging the heart, convergent collimation offers the potential of increased sensitivity over that of parallel-hole collimation. However, if a cone-beam collimated gamma camera is rotated in a planar orbit, the projection data obtained are not complete. Two cone-beam collimators and one fan-beam collimator are used with a three-detector SPECT system. The combined cone-beam/fan-beam collimation provides a complete set of data for image reconstruction. The imaging geometry is evaluated using data acquired from phantom and patient studies. For the Jaszazck cardiac torso phantom experiment, the combined cone-beam/fan-beam collimation provided 1.7 times greater sensitivity than standard parallel-hole collimation (low-energy high-resolution collimators). Also, phantom and patient comparison studies showed improved image quality. The combined cone-beam/fan-beam imaging geometry with appropriate weighting of the two data sets provides improved system sensitivity while measuring sufficient data for artifact free cardiac images

Bacteriological profile and antibiotic sensitivity pattern in patients with Urinary tract infection

OpenAIRE

N Subedi; S Pudasaini

2017-01-01

Background: Urinary tract infection is one of the common bacterial infections seeking treatment in clinical practice. A variety of organisms are associated with UTI and the most common organisms are Escherichia coli and other coliforms. Bacteriological investigations of UTI are not complete without antibiotic sensitivity test of the isolate. The aim of this study is to determine the bacteriological profile and antibiotic sensitivity patterns and their disease association.Materials and methods...

Measurement of profile and intensity of proton beam by an integrating current transformer and a segmented parallel-plate ion chamber for the AGS-spallation target experiment (ASTE)

International Nuclear Information System (INIS)

Meigo, Shin-ichiro; Nakashima, Hiroshi; Takada, Hiroshi

2001-03-01

Profile and intensity of proton beams incident to a mercury target were measured for the experiments under AGS-spallation Target Experiment (ASTE) collaboration. Protons of 1.94, 12 and 24 GeV energy were measured for a temperature, pressure wave and neutronics in the mercury target. For the beam profile measurement, segmented parallel-plate ion chamber (CHIDORI) was used as the online detector. Imaging plates (IP) were also used for the profile measurement with aluminum activation foils as the image converter. An integrating current transformer (ICT) and activation method by Cu foil were used for the measurement of beam intensity. The beam profile obtained by CHIDORI gives a good agreement with the results with the IP. The beam intensity obtained by ICT agrees with the data obtained by the activation technique within ±3% for 12 and 24 GeV cases. Furthermore, these results show in good agreement with those obtained by the monitor of segmented wire ionization chamber (SWIC) and secondary emission chamber (SEC) installed by the AGS team. Therefore, a reliable beam monitor technique was established, so that the analysis of the experiment such as temperature and pressure wave can be normalized by the number of incident protons. (author)

A Micromegas Detector for Neutron Beam Imaging at the n_TOF Facility at CERN

CERN Document Server

Belloni, F; Berthoumieux, E; Calviani, M; Chiaveri, E; Colonna, N; Giomataris, Y; Guerrero, C; Gunsing, F; Iguaz, F J; Kebbiri, M; Pancin, J; Papaevangelou, T; Tsinganis, A; Vlachoudis, V; Altstadt, S; Andrzejewski, J; Audouin, L; Barbagallo, M; Bécares, V; Bečvář, F; Billowes, J; Boccone, V; Bosnar, D; Brugger, M; Calviño, F; Cano-Ott, D; Carrapiço, C; Cerutti, F; Chiaveri, E; Chin, M; Cortés, G; Corté-Giraldo, M A; Diakaki, M; Domingo-Pardo, C; Duran, I; Dzysiuk, N; Eleftheriadis, C; Ferrari, A; Fraval, K; Ganesan, S; García, A R; Giubrone, G; Gómez-Hornillos, M B; Gonçalves, I F; González-Romero, E; Griesmayer, E; Gurusamy, P; Jenkins, D G; Jericha, E; Kadi, Y; Käppeler, F; Karadimos, D; Koehler, P; Kokkoris, M; Krtička, M; Kroll, J; Langer, C; Lederer, C; Leeb, H; Leong, L S; Losito, R; Manousos, A; Marganiec, J; Marítnez, T; Massimi, C; Mastinu, P F; Mastromarco, M; Meaze, M; Mendoza, E; Mengoni, A; Milazzo, P M; Mingrone, F; Mirea, M; Mondalaers, W; Paradela, C; Pavlik, A; Perkowski, J; Plompen, A J M; Praena, J; Quesada, J M; Rauscher, T; Reifarth, R; Riego, A; Roman, F; Rubbia, C; Sarmento, R; Schillebeeckx, P; Schmidt, S; Tagliente, G; Tain, J L; Tarrío, D; Tassan-Got, L; Valenta, S; Vannini, G; Variale, V; Vaz, P; Ventura, A; Versaci, R; Vermeulen, M J; Vlastou, R; Wallner, A; Ware, T; Weigand, M; Weiss, C; Wright, T J; Žugec, P

2014-01-01

Micromegas (Micro-MEsh Gaseous Structure) detectors are gas detectors consisting of a stack of one ionization and one proportional chamber. A micromesh separates the two communicating regions, where two different electric fields establish respectively a charge drift and a charge multiplication regime. The n\\_TOF facility at CERN provides a white neutron beam (from thermal up to GeV neutrons) for neutron induced cross section measurements. These measurements need a perfect knowlodge of the incident neutron beam, in particular regarding its spatial profile. A position sensitive micromegas detector equipped with a B-10 based neutron/charged particle converter has been extensively used at the n\\_TOF facility for characterizing the neutron beam profile and extracting the beam interception factor for samples of different size. The boron converter allowed to scan the energy region of interest for neutron induced capture reactions as a function of the neutron energy, determined by the time of flight. Experimental ...

Breathability studies of electron beam curable polyurethane pressure sensitive adhesive for bio-medical application

International Nuclear Information System (INIS)

Singh, Anil Kumar; Mehra, Dayal Singh; Niyogi, Utpal Kumar; Sabharwal, Sunil; Singh, Gurdeep

2014-01-01

Polyurethane (PU) based pressure sensitive adhesive (PSA) commonly used in surgical dressing has been made by electron beam (e-beam) irradiation. In contact with biological substrate like skin, PSAs generally lose their adhesive strength due to very low moisture vapor transmission rate (MVTR). In the present study, effects of varying e-beam dose and different crosslinkers on the MVTR of the PU-PSA have been investigated. A comparative study of effects of different crosslinkers showed that PU-PSA with IPDI has the least while that with TAC has the highest gel content and crystallinity and a reverse trend was observed for the MVTR. - Highlights: • On increasing e-beam dose from 5 kGy to 60 kGy the MVTR decreased continuously. • Increasing crosslinker concentration from 2% to10% resulted in decrease of MVTR. • IPDI has the highest and TAC has the least MVTR in PU-PSA system among the crosslinkers. • MVTR/peel adhesion/shear adhesion/initial tack: IPDI>MDI>CMDI>PMDI>TAIC>TAC. • Gel content/T g /crystallinity: TAC>TAIC>PMDI>CMDI>MDI>IPDI

Feasibility studies of using thin entrance window photodiodes for clinical electron beam dosimetry

International Nuclear Information System (INIS)

Nascimento, Cristina R.; Asfora, Viviane K.; Barros, Vinicius S.M.; Gonçalves, Josemary A.C.; Andrade, Lucas F.R.; Khoury, Helen J.; Bueno, Carmen C.

2017-01-01

The response of the commercial XRA-24 PIN photodiode (5.76 mm 2 active area) for clinical electron beam dosimetry covering the range of 8-12 MeV was investigated. Within this energy range, the charge generated in the diode's sensitive volume is linearly dependent on the absorbed dose up to 320 cGy. However, charge sensitivity coefficients evidenced that the dose response of the diode is slightly dependent on the electron beam energy. Indeed, the diode's energy dependence was within 8.5% for 8-12MeV electron beams. On the other hand, it was also observed an excellent repeatability of these results with a variation coefficient (VC) lower than 0.4%, which is within the 1% tolerance limit recommended by the AAPM TG-62. Furthermore, the agreement between the percentage depth dose profiles (PDD) gathered with the diode and the ionization chamber allowed achieving the electron beam quality within 1% of that obtained with the ionization chamber. Based on these results, the photodiode XRA-24 can be a reliable and inexpensive alternative for electron beams dosimetry. (author)

Dosimetry study for electron beam irradiation in radiation processing

International Nuclear Information System (INIS)

Sunaga, Hiromi; Haruyama, Yasuyuki; Takizawa, Haruki; Kojima, Takuji; Yotsumoto, Keiichi

1995-01-01

For certain critical applications such as medical device sterilization and food irradiation, accurate calibration of electron energy and absorbed dose is required to assure the quality of irradiated products. To meet this requirement, TRCRE, JAERI has carried out research and development on high dose radiation dosimetry for electron beams in the energy range used in radiation processing (0.15 - 3.0 MeV). JAERI has developed a simultaneous electron beam energy and dosimeter calibration system that consist of a total absorption calorimeter, an electron current density meter, and a stacked thin-film dosimeter set. For low energy electrons, where it is important to measure the depth-dose profile in materials with high depth resolution, we studied the feasibility of a method using Gafchromic film dosimeters. This film, which has an 8-μm thick sensitive layer, is combined with a stepped array of absorber films of the same thickness to produce a high-resolution depth-dose profile on the Gafchromic film. The depth-dose profile obtained in this manner has about five times greater resolution than conventional radiochromic film dosimetry. (author)

Transverse electron beam diagnostics at REGAE

Energy Technology Data Exchange (ETDEWEB)

Bayesteh, Shima

2014-12-15

comparison of the measured emittance values to the ones obtained from simulations, shows that they are in agreement. It is demonstrated that with an excellent sensitivity that enables the determination of both the transverse charge distribution and the emittance at very low charges, the profile monitors can provide a measure of the coherence of the beam, as well as of the diffraction quality in every shot of a progressive sequence.

Transverse electron beam diagnostics at REGAE

International Nuclear Information System (INIS)

Bayesteh, Shima

2014-12-01

comparison of the measured emittance values to the ones obtained from simulations, shows that they are in agreement. It is demonstrated that with an excellent sensitivity that enables the determination of both the transverse charge distribution and the emittance at very low charges, the profile monitors can provide a measure of the coherence of the beam, as well as of the diffraction quality in every shot of a progressive sequence.

Depth profile analysis of thin TiOxNy films using standard ion beam analysis techniques and HERDA

International Nuclear Information System (INIS)

Markwitz, A.; Dytlewski, N.; Cohen, D.

1999-01-01

Ion beam assisted deposition is used to fabricate thin titanium oxynitride films (TiO x N y ) at Industrial Research (typical film thickness 100nm). At the Institute of Geological and Nuclear Sciences, the thin films are analysed using non-destructive standard ion beam analysis (IBA) techniques. High-resolution titanium depth profiles are measured with RBS using 1.5MeV 4 He + ions. Non-resonant nuclear reaction analysis (NRA) is performed for investigating the amounts of O and N in the deposited films using the reactions 16 O(d,p) 17 O at 920 keV and 14 N(d,α) 12 C at 1.4 MeV. Using a combination of these nuclear techniques, the stoichiometry as well as the thickness of the layers is revealed. However, when oxygen and nitrogen depth profiles are required for investigating stoichiometric changes in the films, additional nuclear analysis techniques such as heavy ion elastic recoil detection (HERDA) have to be applied. With HERDA, depth profiles of N, O, and Ti are measured simultaneously. In this paper comparative IBA measurement s of TiO x N y films with different compositions are presented and discussed

Degradation effects ad Si-depth profiling in photoresists using ion beam analysis

International Nuclear Information System (INIS)

Ijzendoorn, L.J. van; Schellekens, J.P.W.

1989-01-01

The reaction of silicon-containing vapour with a photoresist layer, as used in dry developable lithographic processes, was studied with Rutherford backscattering spectrometry (RBS). Degradation of the polymer layer was observed, but the total amount of incorporated Si was found to be constant during the measurement. Si-depth profiles were found to be independent of dose and in agreement with profiles obtained with secondary ion mass spectrometry (SIMS). The detection of hydrogen by elastic recoil detection (ERD) was used to study the degradation in detail. The decrease in hydrogen countrate from a layer of polystyrene on Si in combination with the shift of the Si-substrate edge in the corresponding RBS spectra was used for a model description. Only one degradation cross-section for hydrogen and one for carbon, both independent of beam current and dose, were required for a successful fit of the experimental data. (orig.)

Distinct fermentation and antibiotic sensitivity profiles exist in salmonellae of canine and human origin.

Science.gov (United States)

Wallis, Corrin V; Lowden, Preena; Marshall-Jones, Zoe V; Hilton, Anthony C

2018-02-26

Salmonella enterica is a recognised cause of diarrhoea in dogs and humans, yet the potential for transfer of salmonellosis between dogs and their owners is unclear, with reported evidence both for and against Salmonella as a zoonotic pathogen. A collection of 174 S. enterica isolates from clinical infections in humans and dogs were analysed for serotype distribution, carbon source utilisation, chemical and antimicrobial sensitivity profiles. The aim of the study was to understand the degree of conservation in phenotypic characteristics of isolates across host species. Serovar distribution across human and canine isolates demonstrated nine serovars common to both host species, 24 serovars present in only the canine collection and 39 solely represented within the human collection. Significant differences in carbon source utilisation profiles and ampicillin, amoxicillin and chloramphenicol sensitivity profiles were detected in isolates of human and canine origin. Differences between the human and canine Salmonella collections were suggestive of evolutionary separation, with canine isolates better able to utilise several simple sugars than their human counterparts. Generally higher minimum inhibitory concentrations of three broad-spectrum antimicrobials, commonly used in veterinary medicine, were also observed in canine S. enterica isolates. Differential carbon source utilisation and antimicrobial sensitivity profiles in pathogenic Salmonella isolated from humans and dogs are suggestive of distinct reservoirs of infection for these hosts. Although these findings do not preclude zoonotic or anthroponotic potential in salmonellae, the separation of carbon utilisation and antibiotic profiles with isolate source is indicative that infectious isolates are not part of a common reservoir shared frequently between these host species.

Sub-millisecond electron density profile measurement at the JET tokamak with the fast lithium beam emission spectroscopy system

Science.gov (United States)

Réfy, D. I.; Brix, M.; Gomes, R.; Tál, B.; Zoletnik, S.; Dunai, D.; Kocsis, G.; Kálvin, S.; Szabolics, T.; JET Contributors

2018-04-01

Diagnostic alkali atom (e.g., lithium) beams are routinely used to diagnose magnetically confined plasmas, namely, to measure the plasma electron density profile in the edge and the scrape off layer region. A light splitting optics system was installed into the observation system of the lithium beam emission spectroscopy diagnostic at the Joint European Torus (JET) tokamak, which allows simultaneous measurement of the beam light emission with a spectrometer and a fast avalanche photodiode (APD) camera. The spectrometer measurement allows density profile reconstruction with ˜10 ms time resolution, absolute position calculation from the Doppler shift, spectral background subtraction as well as relative intensity calibration of the channels for each discharge. The APD system is capable of measuring light intensities on the microsecond time scale. However ˜100 μs integration is needed to have an acceptable signal to noise ratio due to moderate light levels. Fast modulation of the beam up to 30 kHz is implemented which allows background subtraction on the 100 μs time scale. The measurement covers the 0.9 background subtraction, the relative calibration, and the comprehensive error calculation, runs a Bayesian density reconstruction code, and loads results to the JET database. The paper demonstrates the capability of the APD system by analyzing fast phenomena like pellet injection and edge localized modes.

Transverse wakefield effects in the two-beam accelerator

International Nuclear Information System (INIS)

Selph, F.; Sessler, A.

1986-01-01

Transverse wakefield effects in the high-gradient accelerating structure of the two-beam accelerator (TBA) are analyzed theoretically using three different models. The first is a very simple two-particle model, the second is for a beam with uniform charge distribution, constant betatron wavelength, and a linear wake approximation. Both of these models give analytic scaling laws. The third model has a Gaussian beam (represented by 11 superparticles), energy variation across the bunch, acceleration, variation of betatron focusing with energy, and variation of the wakefield from linearity. The three models are compared, and the third model is used to explore the wakefield effects when accelerator parameters such as energy, energy spread, injection energy, accelerating gradient, and betatron wavelength are varied. Also explored are the sensitivity of the beam to the wakefield profile to the longitudinal charge distribution. Finally, in consideration of wakefield effects, possible parameters of a TBA are presented. (orig./HSI)

Arbitrary Control of Polarization and Intensity Profiles of Diffraction-Attenuation-Resistant Beams along the Propagation Direction

Science.gov (United States)

Corato-Zanarella, Mateus; Dorrah, Ahmed H.; Zamboni-Rached, Michel; Mojahedi, Mo

2018-02-01

We report on the theory and experimental generation of a class of diffraction-attenuation-resistant beams with state of polarization (SOP) and intensity that can be controlled on demand along the propagation direction. This control is achieved by a suitable superposition of Bessel beams, whose parameters are systematically chosen based on closed-form analytic expressions provided by the frozen waves method. Using an amplitude-only spatial light modulator, we experimentally demonstrate three scenarios. In the first, the SOP of a horizontally polarized beam evolves to radial polarization and is then changed to vertical polarization, with the beam intensity held constant. In the second, we simultaneously control the SOP and the longitudinal intensity profile, which is chosen such that the beam's central ring can be switched off over predefined space regions, thus generating multiple foci with different SOPs and at different intensity levels along the propagation. Finally, the ability to control the SOP while overcoming attenuation inside lossy fluids is shown experimentally. We envision our proposed method to be of great interest for many applications, such as optical tweezers, atom guiding, material processing, microscopy, and optical communications.

Effect of a resonant excitation on the evolution of the beam emittance and halo population

CERN Document Server

Fitterer, Miriam; Valishev, Alexander; Bruce, Roderik; Papadopoulou, Parthena Stefania; Papotti, Giulia; Pellegrini, Dario; Redaelli, Stefano; Trad, Georges; Valuch, Daniel; Valentino, Gianluca; Wagner, Joschka; Xu, Chen; CERN. Geneva. ATS Department

2017-01-01

Collimation with hollow electron beams or lenses (HEL) is currently one of the most promising concepts for active halo control in HL-LHC. In previous studies it has been shown that the halo can be efficiently removed with a hollow electron lens. Equally important as an efficient removal of the halo, is to demonstrate that the core stays unperturbed. In the case of an ideal hollow electron lens without bends, the field at the location of the beam core vanishes and the core remains unperturbed. In reality, the field at the beam core does not vanish entirely due to imperfections in the electron beam profile and the electron lens bends necessary to guide the electron in and out of the proton aperture. In particular, in the case of a pulsed operation of the electron lens the non-vanishing residual field induces noise on the proton beam. To identify the most sensitive pulsing patterns for the resonant mode and derive tolerances on the profile imperfections, a first MD was carried out of which the first results...

Effect of a resonant excitation on the evolution of the beam emittance and halo population

CERN Document Server

Fitterer, Miriam; Valishev, Alexander; Bruce, Roderik; Redaelli, Stefano; Salvachua Ferrando, Belen Maria; Valuch, Daniel; Valentino, Gianluca; Wagner, Joschka; CERN. Geneva. ATS Department

2018-01-01

Collimation with hollow electron beams or lenses (HEL) is currently one of the most promising concepts for active halo control in HL-LHC. In previous studies it has been shown that the halo can be efficiently removed with a hollow electron lens. Equally important as an efficient removal of the halo, is to demonstrate that the core stays unperturbed. In the case of an ideal hollow electron lens without bends, the field at the location of the beam core vanishes and the core thus remains unperturbed. In reality, the field at the beam core does not vanish entirely due to imperfections in the electron beam profile and the electron lens bends necessary to guide the electron in and out of the proton aperture. In particular, in the case of a pulsed operation of the electron lens the non-vanishing residual field induces noise on the proton beam. To identify the most sensitive pulsing patterns for the resonant mode and derive tolerances on the profile imperfections, a first MD (MD1415) was carried out on 24.08.2016 [1]...

Beam Extinction Monitoring in the Mu2e Experiment

Energy Technology Data Exchange (ETDEWEB)

Prebys, Eric [Fermilab; Bartoszek, Larry [Technicare; Gaponenko, Andrei [Fermilab; Kasper, Peter [Fermilab

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.

Design of the beam profile monitor system for the RHIC injection line

International Nuclear Information System (INIS)

Witkover, R.L.

1995-01-01

A video profile monitor (VPM) system will be used in the AGS-to-RHIC (ATR) transfer line to acquire single bunches transferred at 30 Hz. An array of 12 video cameras will be connected to 4 frame grabbers through a wide-band flux. Fast VME image processing boards will analyze a 120 x 120 subset of the image, generated by a 4 x 4 convolution or an ROI computation and sent over the network during the AGS recycle time. Details of the design, results of lab tests and studies with ion and proton beams will be presented

Inspection of commercial optical devices for data storage using a three Gaussian beam microscope interferometer

International Nuclear Information System (INIS)

Flores, J. Mauricio; Cywiak, Moises; Servin, Manuel; Juarez P, Lorenzo

2008-01-01

Recently, an interferometric profilometer based on the heterodyning of three Gaussian beams has been reported. This microscope interferometer, called a three Gaussian beam interferometer, has been used to profile high quality optical surfaces that exhibit constant reflectivity with high vertical resolution and lateral resolution near λ. We report the use of this interferometer to measure the profiles of two commercially available optical surfaces for data storage, namely, the compact disk (CD-R) and the digital versatile disk (DVD-R). We include experimental results from a one-dimensional radial scan of these devices without data marks. The measurements are taken by placing the devices with the polycarbonate surface facing the probe beam of the interferometer. This microscope interferometer is unique when compared with other optical measuring instruments because it uses narrowband detection, filters out undesirable noisy signals, and because the amplitude of the output voltage signal is basically proportional to the local vertical height of the surface under test, thus detecting with high sensitivity. We show that the resulting profiles, measured with this interferometer across the polycarbonate layer, provide valuable information about the track profiles, making this interferometer a suitable tool for quality control of surface storage devices

Correction of X-ray diffraction profiles in linear-type PSPC by position factor

International Nuclear Information System (INIS)

Takahashi, Toshio

1992-01-01

PSPC (Position Sensitive Proportional Counter) makes it possible to obtain one-dimentional diffraction profiles without mechanical scanning. In a linear-type PSPC, the obtained profiles need correcting, because the position factor influences the intensity of the diffracted X-ray beam and the counting rate at each position on PSPC. The distances from the specimen are not the same at the center and at the edge of the detector, and the intensity decreases at the edge because of radiation and absorption. The counting rate varies with the incident angle of the diffracted beam at each position on PSPC. The position factor f i at channel i of the multichannel-analyser is given by f i = cos 4 α i ·exp{-μR(1/cosα i -1)} where R is the distance between the specimen and the center of PSPC, μ is the linear absorption coefficient and α i is the incident angle of the diffracted beam at channel i. The background profiles of silica gel powder were measured with CrKα and CuKα. The parameters of the model function were fitted to the profiles by the non-linear least squares method. The agreement between these parameters and the calculated values shows that the position factor can correct the measured profiles properly. (author)

Depth profiling of residual activity of ^{237}U fragments as a range verification technique for ^{238}U primary ion beam

Directory of Open Access Journals (Sweden)

I. Strašík

2012-07-01

Full Text Available Experimental and simulation data concerning fragmentation of ^{238}U ion beam in aluminum, copper, and stainless-steel targets with the initial energy 500 and 950  MeV/u are collected in the paper. A range-verification technique based on depth profiling of residual activity is presented. The irradiated targets were constructed in the stacked-foil geometry and analyzed using gamma-ray spectroscopy. One of the purposes of these experiments was depth profiling of residual activity of induced nuclides and projectile fragments. Among the projectile fragments, special attention is paid to the ^{237}U isotope that has a range very close to the range of the primary ^{238}U ions. Therefore, the depth profiling of the ^{237}U isotope can be utilized for experimental verification of the ^{238}U primary-beam range, which is demonstrated and discussed in the paper. The experimental data are compared with computer simulations by FLUKA, SRIM, and ATIMA, as well as with complementary experiments.

Self-reconstruction of diffraction-free and accelerating laser beams in scattering media

International Nuclear Information System (INIS)

Ersoy, T.; Yalizay, B.; Akturk, S.

2012-01-01

We experimentally investigate propagation of laser beams with different intensity profiles in highly scattering media. We generate transverse laser amplitude profiles with Gaussian, Bessel and Airy function envelopes. We then propagate these beams through optical phantoms formed with variable density intralipid solutions. At the sample exit, we compare change in maximum intensities, as well as beam profile reconstruction. We show that self-reconstruction properties of Bessel and Airy beams bring about slower decrease in maximum intensity with increasing scatterer density. On the other hand, the beam profiles deteriorate faster, as compared to reference Gaussian beams. Slower decrease in the intensity can be attributed to the wavevector spectra providing a continuous flow of energy to the beam center, while beam deterioration is linked to total beam volume in the scattering medium. These results show that beam shaping methods can significantly enhance delivery of intense light deeper into turbid media, but this enhancement is compromised by stronger speckling of beam profiles. -- Highlights: ► We experimentally investigate propagation of shaped laser beams in turbid media. ► Peak intensity of Bessel and Airy beams decrease slower with increasing scatterer. ► Shaped beam profiles deteriorate faster, as compared to reference Gaussian beams. ► Shaped beam profiles can enhance applications of lasers inscattering media.

Sensitivity of molecular marker-based CMB models to biomass burning source profiles

Science.gov (United States)

Sheesley, Rebecca J.; Schauer, James J.; Zheng, Mei; Wang, Bo

To assess the contribution of sources to fine particulate organic carbon (OC) at four sites in North Carolina, USA, a molecular marker chemical mass balance model (MM-CMB) was used to quantify seasonal contributions for 2 years. The biomass burning contribution at these sites was found to be 30-50% of the annual OC concentration. In order to provide a better understanding of the uncertainty in MM-CMB model results, a biomass burning profile sensitivity test was performed on the 18 seasonal composites. The results using reconstructed emission profiles based on published profiles compared well, while model results using a single source test profile resulted in biomass burning contributions that were more variable. The biomass burning contribution calculated using an average regional profile of fireplace emissions from five southeastern tree species also compared well with an average profile of open burning of pine-dominated forest from Georgia. The standard deviation of the results using different source profiles was a little over 30% of the annual average biomass contributions. Because the biomass burning contribution accounted for 30-50% of the OC at these sites, the choice of profile also impacted the motor vehicle source attribution due to the common emission of elemental carbon and polycyclic aromatic hydrocarbons. The total mobile organic carbon contribution was less effected by the biomass burning profile than the relative contributions from gasoline and diesel engines.

Sensitivity of the urban airshed model to mixing height profiles

Energy Technology Data Exchange (ETDEWEB)

Rao, S.T.; Sistla, G.; Ku, J.Y.; Zhou, N.; Hao, W. [New York State Dept. of Environmental Conservation, Albany, NY (United States)

1994-12-31

The United States Environmental Protection Agency (USEPA) has recommended the use of the Urban Airshed Model (UAM), a grid-based photochemical model, for regulatory applications. One of the important parameters in applications of the UAM is the height of the mixed layer or the diffusion break. In this study, we examine the sensitivity of the UAM-predicted ozone concentrations to (a) a spatially invariant diurnal mixing height profile, and (b) a spatially varying diurnal mixing height profile for a high ozone episode of July 1988 for the New York Airshed. The 1985/88 emissions inventory used in the EPA`s Regional Oxidant Modeling simulations has been regridded for this study. Preliminary results suggest that the spatially varying case yields a higher peak ozone concentrations compared to the spatially invariant mixing height simulation, with differences in the peak ozone ranging from a few ppb to about 40 ppb for the days simulated. These differences are attributed to the differences in the shape of the mixing height profiles and its rate of growth during the morning hours when peak emissions are injected into the atmosphere. Examination of the impact of emissions reductions associated with these two mixing height profiles indicates that NO{sub x}-focussed controls provide a greater change in the predicted ozone peak under spatially invariant mixing heights than under the spatially varying mixing height profile. On the other hand, VOC-focussed controls provide a greater change in the predicted peak ozone levels under spatially varying mixing heights than under the spatially invariant mixing height profile.

Status and test report on the LANL-Boeing APLE/HPO flying-wire beam-profile monitor. Status report

Energy Technology Data Exchange (ETDEWEB)

Wilke, M.; Barlow, D.; Fortgang, C.; Gilpatrick, J.; Meyer, R.; Rendon, A.; Warren, D. [Los Alamos National Lab., NM (United States); Greegor, R. [Boeing Co., Seattle, WA (United States)

1994-07-01

The High-Power Oscillator (HPO) demonstration of the Average Power Laser Experiment (APLE) is a collaboration by Los Alamos National Laboratory and Boeing to demonstrate a 10 kW average power, 10 {mu}m free electron laser (FEL). As part of the collaboration, Los Alamos National Laboratory (LANL) is responsible for many of the electron beam diagnostics in the linac, transport, and laser sections. Because of the high duty factor and power of the electron beam, special diagnostics are required. This report describes the flying wire diagnostic required to monitor the beam profile during high-power, high-duty operation. The authors describe the diagnostic and prototype tests on the Los Alamos APLE Prototype Experiment (APEX) FEL. They also describe the current status of the flying wires being built for APLE.

Electron beam emittance monitor for the SSC

International Nuclear Information System (INIS)

Tsyganov, E.; Meinke, R.; Nexsen, W.; Kauffmann, S.; Zinchenko, A.; Taratin, A.

1993-05-01

A nondestructive beam profile monitor for the Superconducting Super Collider (SSC) is presented using as a probe a low-energy electron beam interacting with the proton bunch charge. Results using a full Monte Carlo simulation code look promising for the transverse and longitudinal beam profile measurements

Contact and respiratory sensitizers can be identified by cytokine profiles following inhalation exposure

International Nuclear Information System (INIS)

De Jong, Wim H.; Arts, Josje H.E.; De Klerk, Arja; Schijf, Marcel A.; Ezendam, Janine; Kuper, C. Frieke; Van Loveren, Henk

2009-01-01

There are currently no validated animal models that can identify low molecular weight (LMW) respiratory sensitizers. The Local Lymph Node Assay (LLNA) is a validated animal model developed to detect contact sensitizers using skin exposure, but all LMW respiratory sensitizers tested so far were also positive in this assay. Discrimination between contact and respiratory sensitizers can be achieved by the assessment of cytokine profiles. In a LLNA using the inhalation route, both contact and respiratory sensitizers enhanced proliferation in the draining lymph nodes. The question was if their cytokine profiles were affected by the route of exposure. Male BALB/c mice were exposed head/nose-only during 3 consecutive days to the respiratory sensitizers trimellitic anhydride, phthalic anhydride, toluene diisocyanate, hexamethylene diisocyanate (HDI), and isophorone diisocyanate; the contact sensitizers dinitrochlorobenzene (DNCB), oxazolone (OXA) and formaldehyde (FA), and the irritant methyl salicylate (MS). Three days after the last exposure the draining lymph nodes were excised and cytokine production was measured after ex vivo stimulation with Concanavalin A. Skin application was used as a positive control. After inhalation exposure the respiratory sensitizers induced more interleukin-4 (IL-4) and interleukin (IL-10) compared to the contact sensitizers, whereas the contact sensitizers, except formaldehyde, induced relatively more interferon-γ (IFN-γ) production. When IL-4 and IFN-γ were plotted as a function of the proliferative response, it was shown that IL-4 could be used to identify respiratory sensitizers, except HDI, at concentration levels inducing intermediate stimulation indices. HDI could be distinguished from DNCB and OXA at high SI values. In contrast, contact sensitizers could only be identified when IFN-γ was measured at high stimulation indices. The skin positive control, tested at high concentrations, showed comparable results for IL-4 and IL-10

The beam diagnostic instruments in Beijing radioactive ion-beam facilities isotope separator on-line

International Nuclear Information System (INIS)

Ma, Y.; Cui, B.; Ma, R.; Tang, B.; Chen, L.; Huang, Q.; Jiang, W.

2014-01-01

The beam diagnostic instruments for Beijing Radioactive Ion-beam Facilities Isotope Separator On-Line are introduced [B. Q. Cui, Z. H. Peng, Y. J. Ma, R. G. Ma, B. Tang, T. Zhang, and W. S. Jiang, Nucl. Instrum. Methods 266, 4113 (2008); T. J. Zhang, X. L. Guan, and B. Q. Cui, in Proceedings of APAC 2004, Gyeongju, Korea, 2004, http://www.jacow.org , p. 267]. For low intensity ion beam [30–300 keV/1 pA–10 μA], the beam profile monitor, the emittance measurement unit, and the analyzing slit will be installed. For the primary proton beam [100 MeV/200 μA], the beam profile scanner will be installed. For identification of the nuclide, a beam identification unit will be installed. The details of prototype of the beam diagnostic units and some experiment results will be described in this article

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

Science.gov (United States)

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

2018-06-01

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

Spatial variation of the section sensitivity profile in helical CT

International Nuclear Information System (INIS)

Katsuta, Shoichi; Hanai, Kouzou; Kunii, Takeo; Kimura, Haruki; Imabayashi, Wataru; Muramatsu, Yoshihisa

1999-01-01

The section sensitivity profile (SSP) is adequate to express the properties of helical CT images. Although SSP measurement has been performed only at the center of the imaging field, we applied it to off-center positions using a metal bead and controlled tracking technique. The experimental results indicated that SSP curves vary in the imaging field according to the relative position of the x-ray focus. The results were in agreement with computer simulations. (author)

Feasibility studies of using thin entrance window photodiodes for clinical electron beam dosimetry

Energy Technology Data Exchange (ETDEWEB)

Nascimento, Cristina R.; Asfora, Viviane K.; Barros, Vinicius S.M.; Gonçalves, Josemary A.C.; Andrade, Lucas F.R.; Khoury, Helen J.; Bueno, Carmen C., E-mail: vsmdbarros@gmail.com, E-mail: vikhoury@gmail.com, E-mail: hjkhoury@gmail.com, E-mail: cristinaramos@smartsat.com.br, E-mail: josemary@ipen.br, E-mail: ccbueno@ipen.br [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil); Instituto Federal de Educação, Ciência e Tecnologia de Pernambuco (IFPE), Recife-PE (Brazil). Departamento de Energia Nuclear; Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Santa Casa de Misericórdia de Itabuna, BA (Brazil)

2017-11-01

The response of the commercial XRA-24 PIN photodiode (5.76 mm{sup 2} active area) for clinical electron beam dosimetry covering the range of 8-12 MeV was investigated. Within this energy range, the charge generated in the diode's sensitive volume is linearly dependent on the absorbed dose up to 320 cGy. However, charge sensitivity coefficients evidenced that the dose response of the diode is slightly dependent on the electron beam energy. Indeed, the diode's energy dependence was within 8.5% for 8-12MeV electron beams. On the other hand, it was also observed an excellent repeatability of these results with a variation coefficient (VC) lower than 0.4%, which is within the 1% tolerance limit recommended by the AAPM TG-62. Furthermore, the agreement between the percentage depth dose profiles (PDD) gathered with the diode and the ionization chamber allowed achieving the electron beam quality within 1% of that obtained with the ionization chamber. Based on these results, the photodiode XRA-24 can be a reliable and inexpensive alternative for electron beams dosimetry. (author)

X-ray beam-shaping via deformable mirrors: surface profile and point spread function computation for Gaussian beams using physical optics.

Science.gov (United States)

Spiga, D

2018-01-01

X-ray mirrors with high focusing performances are commonly used in different sectors of science, such as X-ray astronomy, medical imaging and synchrotron/free-electron laser beamlines. While deformations of the mirror profile may cause degradation of the focus sharpness, a deliberate deformation of the mirror can be made to endow the focus with a desired size and distribution, via piezo actuators. The resulting profile can be characterized with suitable metrology tools and correlated with the expected optical quality via a wavefront propagation code or, sometimes, predicted using geometric optics. In the latter case and for the special class of profile deformations with monotonically increasing derivative, i.e. concave upwards, the point spread function (PSF) can even be predicted analytically. Moreover, under these assumptions, the relation can also be reversed: from the desired PSF the required profile deformation can be computed analytically, avoiding the use of trial-and-error search codes. However, the computation has been so far limited to geometric optics, which entailed some limitations: for example, mirror diffraction effects and the size of the coherent X-ray source were not considered. In this paper, the beam-shaping formalism in the framework of physical optics is reviewed, in the limit of small light wavelengths and in the case of Gaussian intensity wavefronts. Some examples of shaped profiles are also shown, aiming at turning a Gaussian intensity distribution into a top-hat one, and checks of the shaping performances computing the at-wavelength PSF by means of the WISE code are made.

Ultrahigh-sensitive multimode interference-based fiber optic liquid-level sensor realized using illuminating zero-order Bessel-Gauss beam

Science.gov (United States)

Saha, Ardhendu; Datta, Arijit; Kaman, Surjit

2018-03-01

A proposal toward the enhancement in the sensitivity of a multimode interference-based fiber optic liquid-level sensor is explored analytically using a zero-order Bessel-Gauss (BG) beam as the input source. The sensor head consists of a suitable length of no-core fiber (NCF) sandwiched between two specialty high-order mode fibers. The coupling efficiency of various order modes inside the sensor structure is assessed using guided-mode propagation analysis and the performance of the proposed sensor has been benchmarked against the conventional sensor using a Gaussian beam. Furthermore, the study has been corroborated using a finite-difference beam propagation method in Lumerical's Mode Solutions software to investigate the propagation of the zero-order BG beam inside the sensor structure. Based on the simulation outcomes, the proposed scheme yields a maximum absolute sensitivity of up to 3.551 dB / mm and a sensing resolution of 2.816 × 10 - 3 mm through the choice of an appropriate length of NCF at an operating wavelength of 1.55 μm. Owing to this superior sensing performance, the reported sensing technology expedites an avenue to devise a high-performance fiber optic-level sensor that finds profound implication in different physical, biological, and chemical sensing purposes.

Effective source size, yield and beam profile from multi-layered bremsstrahlung targets

International Nuclear Information System (INIS)

Svensson, R.; Brahme, A.

1996-01-01

Modern conformal radiotherapy benefits from heterogeneous dose delivery using scanned narrow bremsstrahlung beams of high energy in combination with dynamic double focused multi-leaf collimation and purging magnets. When using a purging magnet to remove electrons and positrons the target space is limited and unorthodox thin multi-layered targets are needed. A computational technique has therefore been developed to determine the forward yield and the angular distributions of the bremsstrahlung beam as well as the size and location of the effective and the virtual photon point source for arbitrary multi-layer bremsstrahlung targets. The Gaussian approximation of the diffusion equation for the electrons has been used and convolved with the bremsstrahlung production process. For electrons with arbitrary emittance impinging on targets of any multi-layer and atomic number combination, the model is well applicable, at least for energies in the range 1-100 MeV. The intrinsic bremsstrahlung photon profile has been determined accurately by deconvolving the electron multiple scattering process from thin experimental beryllium target profiles. For electron pencil beams incident on a target of high density and atomic number such as tungsten, the size of the effective photon source stays at around a tenth of a millimetre. The effective photon source for low-Z materials such as Be, C and Al is located at depths from 3-7 mm in the target, decreasing with increasing atomic number. The effective photon source at off-axis positions then moves out considerably from the central axis, which should be considered when aligning collimators. For high-Z materials such as tungsten, the location of the effective photon source is at a few tenths of a millimetre deep. The virtual photon point source is located only a few tenths of a millimetre upstream of the effective photon source both for high- and low-Z materials. For 50 MeV electrons incident on multi-layered full range targets the radial

Electron density profile determination by means of laser blow-off injected neutral beam

International Nuclear Information System (INIS)

Kocsis, G.; Bakos, J.S.; Ignacz, P.N.; Kardon, B.; Koltai, L.; Veres, G.

1992-01-01

This paper is devoted to the experimental and theoretical studies of the determination of the electron density profiles by means of laser blow-off neutrals. For the determination of the density profile the time and spatial distributions of the spectral line radiation intensity of the injected neutrals are used. The method is compared to other previously proposed methods and the advantages and disadvantages of the different methods are discussed. The result of the comparison is that our method gives the most reliable result with the highest temporal resolution for the density profile of the edge plasma. The only disadvantage is the need of careful calibration of the sensitivity of the spatial channels. The advantage is the ability of the method as a standard diagnostic. (orig.)

Characteristics of possible beam losses in superconducting cyclotron

International Nuclear Information System (INIS)

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

2015-01-01

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

Novel manufacturing method by using stainless steel pipes expanded into aluminium profiles for the ITER Neutral Beam cryopumps

Energy Technology Data Exchange (ETDEWEB)

Dremel, Matthias, E-mail: matthias.dremel@iter.org; Boissin, Jean-Claude; Déléage, Vincent; Quinn, Eamonn; Pearce, Robert

2015-10-15

This paper describes the novel engineering and manufacturing solution of stainless steel pipe expansion into aluminium extrusion profiles for use at cryogenic temperatures up to 400 K. This fabrication method will be used for the thermal radiation shields and the cryopanels of the ITER Neutral Beam cryopumps. The use of stainless steel pipes expanded into aluminium extrusion profiles is a solution that combines standard stainless steel welding procedures for the manifolds of the cooling circuits with extended aluminium structures taking advantage of the high thermal conductivity of aluminium. The cryogenic cooling circuits of the pump are a first confinement barrier in the ITER vacuum vessel and the risk of a leakage needs to be minimized as far as possible. The expansion method avoids the need of joints of dissimilar materials in the primary confinement barrier. The fabrication method and results of the prototyping of full scaled components for the ITER Neutral Beam cryopumps are outlined in this paper.

Modeling Drift Compression in an Integrated Beam Experiment for Heavy-Ion-Fusion

Science.gov (United States)

Sharp, W. M.; Barnard, J. J.; Friedman, A.; Grote, D. P.; Celata, C. M.; Yu, S. S.

2003-10-01

The Integrated Beam Experiment (IBX) is an induction accelerator being designed to further develop the science base for heavy-ion fusion. The experiment is being developed jointly by Lawrence Berkeley National Laboratory, Lawrence Livermore National Laboratory, and Princeton Plasma Physics Laboratory. One conceptual approach would first accelerate a 0.5-1 A beam of singly charged potassium ions to 5 MeV, impose a head-to-tail velocity tilt to compress the beam longitudinally, and finally focus the beam radiallly using a series of quadrupole lenses. The lengthwise compression is a critical step because the radial size must be controlled as the current increases, and the beam emittance must be kept minimal. The work reported here first uses the moment-based model HERMES to design the drift-compression beam line and to assess the sensitivity of the final beam profile to beam and lattice errors. The particle-in-cell code WARP is then used to validate the physics design, study the phase-space evolution, and quantify the emittance growth.

Effect of pulsed hollow electron-lens operation on the proton beam core in LHC

Energy Technology Data Exchange (ETDEWEB)

Fitterer, Miriam [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Stancari, Giulio [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Valishev, Alexander [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)

2016-11-08

Collimation with hollow electron beams is currently one of the most promising concepts for active halo control in the HL-LHC. In order to further increase the diffusion rates for a fast halo removal as e.g. desired before the squeeze, the electron lens (e-lens) can be operated in pulsed mode. In case of profile imperfections in the electron beam the pulsing of the e-lens induces noise on the proton beam which can, depending on the frequency content and strength, lead to emittance growth. In order to study the sensitivity to the pulsing pattern and the amplitude, a beam study (machine development MD) at the LHC has been proposed for August 2016 and we present in this note the preparatory simulations and estimates.

Improving depth resolutions in positron beam spectroscopy by concurrent ion-beam sputtering

Science.gov (United States)

John, Marco; Dalla, Ayham; Ibrahim, Alaa M.; Anwand, Wolfgang; Wagner, Andreas; Böttger, Roman; Krause-Rehberg, Reinhard

2018-05-01

The depth resolution of mono-energetic positron annihilation spectroscopy using a positron beam is shown to improve by concurrently removing the sample surface layer during positron beam spectroscopy. During ion-beam sputtering with argon ions, Doppler-broadening spectroscopy is performed with energies ranging from 3 keV to 5 keV allowing for high-resolution defect studies just below the sputtered surface. With this technique, significantly improved depth resolutions could be obtained even at larger depths when compared to standard positron beam experiments which suffer from extended positron implantation profiles at higher positron energies. Our results show that it is possible to investigate layered structures with a thickness of about 4 microns with significantly improved depth resolution. We demonstrated that a purposely generated ion-beam induced defect profile in a silicon sample could be resolved employing the new technique. A depth resolution of less than 100 nm could be reached.

Beam tomography in two and four dimensions

International Nuclear Information System (INIS)

Sander, O.R.; Minerbo, G.N.; Jameson, R.A.; Chamberlin, D.D.

1979-01-01

The coming generations of high beam-power accelerators require new techniques to monitor the emittance and the shape of the beam; in particular, measurements that do not interfere with the beam itself are necessary. A new computational algorithm, MENT (Maximum ENTropy), will be presented that combines nondestructive profile measurements taken from a number of stations along the beam line with beam-dynamics calculations to compute a four-dimensional phase-space distribution. A version of MENT has been used on experimental data to reconstruct the two-dimensional transverse emittance of the Clinton P. Anderson Meson Physics Facility (LAMPF) proton beam at 100 MeV and the H - beam at 750 keV. Wire scanners at three stations were used to get the one-dimensional profiles. Results will be compared with those gained using the destructive slit and collector method and with those gained using MART (Multiplicative Algebraic Reconstruction Technique) on the same three profiles

Diffractive beam shaping for enhanced laser polymer welding

Science.gov (United States)

Rauschenberger, J.; Vogler, D.; Raab, C.; Gubler, U.

2015-03-01

Laser welding of polymers increasingly finds application in a large number of industries such as medical technology, automotive, consumer electronics, textiles or packaging. More and more, it replaces other welding technologies for polymers, e. g. hot-plate, vibration or ultrasonic welding. At the same rate, demands on the quality of the weld, the flexibility of the production system and on processing speed have increased. Traditionally, diode lasers were employed for plastic welding with flat-top beam profiles. With the advent of fiber lasers with excellent beam quality, the possibility to modify and optimize the beam profile by beam-shaping elements has opened. Diffractive optical elements (DOE) can play a crucial role in optimizing the laser intensity profile towards the optimal M-shape beam for enhanced weld seam quality. We present results on significantly improved weld seam width constancy and enlarged process windows compared to Gaussian or flat-top beam profiles. Configurations in which the laser beam diameter and shape can be adapted and optimized without changing or aligning the laser, fiber-optic cable or optical head are shown.

A novel simultaneous photoelastic and two-beam interferometric system: I. Dynamic full-field evaluation of the elasticity modulus profile of polymeric fibres.

Science.gov (United States)

Hamza, A A; Sokkar, T Z N; El-Farahaty, K A; Raslan, M I

2014-06-01

A novel optical setup for simultaneous capturing of photoelastic and two-beam interference patterns was designed. The designed optical setup was used to simultaneously record two types of patterns. The first pattern is two-beam interference pattern, and the second one is photoelastic interference pattern produced by objects under stress. This simultaneous capturing of the two patterns allowed us to calculate the full-field distribution of the elasticity modulus profile of fibres. A mathematical expression of the profile of the elasticity modulus was derived. This was applied to evaluate the elasticity modulus of anisotropic isotactic polypropylene fibres during stretching processes. The profile of the elasticity modulus was determined for both static and dynamic in situ cases where the propagation of different structural deformations was observed and studied using the designed optical setup. Patterns were given for illustration. © 2014 The Authors Journal of Microscopy © 2014 Royal Microscopical Society.

Note: A component-level frequency tunable isolator for vibration-sensitive chips using SMA beams

Energy Technology Data Exchange (ETDEWEB)

Zhang, Xiaoyong, E-mail: zhangxy@buaa.edu.cn, E-mail: yanxiaojun@buaa.edu.cn; Yan, Xiaojun, E-mail: zhangxy@buaa.edu.cn, E-mail: yanxiaojun@buaa.edu.cn [School of Energy and Power Engineering, Beihang University, Beijing 100191 (China); Collaborative Innovation Center of Advanced Aero-Engine, Beijing 100191 (China); National Key Laboratory of Science and Technology on Aero-Engine Aero-Thermodynamics, Beijing 100191 (China); Beijing Key Laboratory of Aero-Engine Structure and Strength, Beijing 100191 (China); Ding, Xin; Wu, Di; Qi, Junlei; Wang, Ruixin; Lu, Siwei [School of Energy and Power Engineering, Beihang University, Beijing 100191 (China)

2016-06-15

This note presents a component-level frequency tunable isolator for vibration-sensitive chips. The isolator employed 8 U-shaped shape memory alloy (SMA) beams to support an isolation island (used for mounting chips). Due to the temperature-induced Young’s modulus variation of SMA, the system stiffness of the isolator can be controlled through heating the SMA beams. In such a way, the natural frequency of the isolator can be tuned. A prototype was fabricated to evaluate the concept. The test results show that the natural frequency of the isolator can be tuned in the range of 64 Hz–97 Hz by applying different heating strategies. Moreover, resonant vibration can be suppressed significantly (the transmissibility decreases about 65% near the resonant frequency) using a real-time tuning method.

Note: A component-level frequency tunable isolator for vibration-sensitive chips using SMA beams

International Nuclear Information System (INIS)

Zhang, Xiaoyong; Yan, Xiaojun; Ding, Xin; Wu, Di; Qi, Junlei; Wang, Ruixin; Lu, Siwei

2016-01-01

This note presents a component-level frequency tunable isolator for vibration-sensitive chips. The isolator employed 8 U-shaped shape memory alloy (SMA) beams to support an isolation island (used for mounting chips). Due to the temperature-induced Young’s modulus variation of SMA, the system stiffness of the isolator can be controlled through heating the SMA beams. In such a way, the natural frequency of the isolator can be tuned. A prototype was fabricated to evaluate the concept. The test results show that the natural frequency of the isolator can be tuned in the range of 64 Hz–97 Hz by applying different heating strategies. Moreover, resonant vibration can be suppressed significantly (the transmissibility decreases about 65% near the resonant frequency) using a real-time tuning method.

Overview of the APT high-energy beam transport and beam expanders

International Nuclear Information System (INIS)

Shafer, R.E.; Blind, B.; Gray, E.R.

1997-01-01

The APT high energy beam transport (HEBT) and beam expanders convey the 1700-MeV, 100-mA cw proton beam from the linac to the tritium target/blanket assembly, or a tuning beam stop. The HEBT includes extensive beam diagnostics, collimators, and beam jitter correction, to monitor and control the 170-MW beam prior to expansion. A zero-degree beamline conveys the beam to the beam stop, and an achromatic bend conveys the beam to the tritium production target. Nonlinear beam expanders make use of higher-order multipole magnets and dithering dipoles to expand the beam to a uniform-density, 16-cm wide by 160-cm high rectangular profile on the tritium-production target. The overall optics design will be reviewed, and beam simulations will be presented

Depth profiling of tritium by neutron time-of-flight

International Nuclear Information System (INIS)

Davis, J.C.; Anderson, J.D.; Lefevre, H.W.

1976-01-01

A method to measure the depth profile of tritium implanted or absorbed in materials was developed. The sample to be analyzed is bombarded with a pulsed proton beam and the energy of neutrons produced by the T(p,n) reaction is measured by the time-of-flight technique. From the neutron energy the depth in the target of the T atoms may be inferred. A sensitivity of 0.1 at. percent T or greater is possible. The technique is non-destructive and may be used with thick or radioactive host materials. Samples up to 20 μm in thickness may be profiled with resolution limited by straggling of the proton beam for depths greater than 1 μm. Deuterium depth profiling has been demonstrated using the D(d,n) reaction. The technique has been used to observe the behavior of an implantation spike of T produced by a 400 keV T + beam stopping at a depth of 3 μm in 11 μm thick layers of Ti and TiH. The presence of H in the Ti lattice is observed to inhibit the diffusion of T through the lattice. Effects of the total hydrogen concentration (H + T) being forced above stochiometry at the implantation site are suggested by the shapes of the implantation spikes

Monitoring the beam flux in molecular beam epitaxy using laser multiphoton ionization

International Nuclear Information System (INIS)

Chien, R.; Sogard, M.R.

1990-01-01

In this paper, we will describe a method using laser nonresonant multiphoton ionization to measure beam flux in molecular beam epitaxy (MBE) systems. The results were obtained in a test chamber where a focused excimer laser beam was used to photoionize a small fraction of the atomic and molecular beams. The constituents of the beams were identified by a time-of-flight mass spectrometer. Ion signal strength was found to be directly correlated to the temperature of the atomic beam oven. Good stability and sensitivity on gallium, aluminum, and silicon atomic beams was demonstrated. Arsenic was also detected. We demonstrated very sensitive detection of contaminant atomic and molecular constituents of our system. We have also detected the presence of short-term fluctuations in the gallium flux from an effusion source. These fluctuations, previously suspected, can be in excess of ±10%

Current profile redistribution driven by neutral beam injection in a reversed-field pinch

Energy Technology Data Exchange (ETDEWEB)

Parke, E. [Department of Physics and Astronomy, University of California Los Angeles 475 Portola Plaza, Los Angeles, California 90095 (United States); Department of Physics, University of Wisconsin-Madison 1150 University Ave., Madison, Wisconsin 53706 (United States); Anderson, J. K.; Den Hartog, D. J. [Department of Physics, University of Wisconsin-Madison 1150 University Ave., Madison, Wisconsin 53706 (United States); Brower, D. L.; Ding, W. X.; Lin, L. [Department of Physics and Astronomy, University of California Los Angeles 475 Portola Plaza, Los Angeles, California 90095 (United States); Johnson, C. A. [Department of Physics, University of Wisconsin-Madison 1150 University Ave., Madison, Wisconsin 53706 (United States); Department of Physics, Auburn University 206 Allison Laboratory, Auburn, Alabama 36849 (United States)

2016-05-15

Neutral beam injection in reversed-field pinch (RFP) plasmas on the Madison Symmetric Torus [Dexter et al., Fusion Sci. Technol. 19, 131 (1991)] drives current redistribution with increased on-axis current density but negligible net current drive. Internal fluctuations correlated with tearing modes are observed on multiple diagnostics; the behavior of tearing mode correlated structures is consistent with flattening of the safety factor profile. The first application of a parametrized model for island flattening to temperature fluctuations in an RFP allows inferrence of rational surface locations for multiple tearing modes. The m = 1, n = 6 mode is observed to shift inward by 1.1 ± 0.6 cm with neutral beam injection. Tearing mode rational surface measurements provide a strong constraint for equilibrium reconstruction, with an estimated reduction of q{sub 0} by 5% and an increase in on-axis current density of 8% ± 5%. The inferred on-axis current drive is consistent with estimates of fast ion density using TRANSP [Goldston et al., J. Comput. Phys. 43, 61 (1981)].

Flattening filter free beams from TrueBeam and Versa HD units: Evaluation of the parameters for quality assurance

Energy Technology Data Exchange (ETDEWEB)

Fogliata, Antonella, E-mail: antonella.fogliata@humanitas.it; Reggiori, Giacomo; Stravato, Antonella; Scorsetti, Marta; Cozzi, Luca [Radiotherapy and Radiosurgery Department, Humanitas Research Hospital, Milan-Rozzano I-20098 (Italy); Fleckenstein, Jens; Schneider, Frank; Lohr, Frank [Department of Radiation Oncology, University Medical Center Mannheim, University of Heidelberg, Mannheim D-68167 (Germany); Pachoud, Marc; Ghandour, Sarah [Radiation Oncology Department, Hôpital Riviera Chablais, Vevey CH-1800 (Switzerland); Krauss, Harald [Radio-Oncology Department, Kaiser Franz Josef Spital, Vienna A-1100 (Austria)

2016-01-15

Purpose: Flattening filter free (FFF) beams generated by medical linear accelerators are today clinically used for stereotactical and non-stereotactical radiotherapy treatments. Such beams differ from the standard flattened beams (FF) in the high dose rate and the profile shape peaked on the beam central axis. Definition of new parameters as unflatness and slope for FFF beams has been proposed based on a renormalization factor for FFF profiles. The present study aims to assess the dosimetric differences between FFF beams generated by linear accelerators from different vendors, and to provide renormalization and parameter data of the two kinds of units. Methods: Dosimetric data from two Varian TrueBeam and two Elekta Versa HD linear accelerators, all with 6 and 10 MV nominal accelerating potentials, FF and FFF modes have been collected. Renormalization factors and related fit parameters according to Fogliata et al. [“Definition of parameters for quality assurance of flattening filter free (FFF) photon beams in radiation therapy,” Med. Phys. 39, 6455–6464 (2012)] have been evaluated for FFF beams of both units and energies. Unflatness and slope parameters from profile curves were evaluated. Dosimetric differences in terms of beam penetration and near-the-surface dose were also assessed. Results: FFF profile parameters have been updated; renormalization factors and unflatness from the Varian units are consistent with the published data. Elekta FFF beam qualities, different from the Varian generated beams, tend to express similar behaviour as the FF beam of the corresponding nominal energy. TPR{sub 20,10} for 6 and 10 MV FF and FFF TrueBeam beams are 0.665, 0.629 (6 MV) and 0.738, 0.703 (10 MV). The same figures for Versa HD units are 0.684, 0.678 (6 MV) and 0.734, 0.721 (10 MV). Conclusions: Renormalization factor and unflatness parameters evaluated from Varian and Elekta FFF beams are provided, in particular renormalization factors table and fit parameters.

Optimizing UV laser focus profiles for improved MALDI performance.

Science.gov (United States)

Holle, Armin; Haase, Andreas; Kayser, Markus; Höhndorf, Jens

2006-06-01

Matrix assisted laser desorption/ionization (MALDI) applications, such as proteomics, genomics, clinical profiling and MALDI imaging, have created a growing demand for faster instrumentation. Since the commonly used nitrogen lasers have throughput and life span limitations, diode-pumped solid-state lasers are an alternative. Unfortunately this type of laser shows clear performance limitations in MALDI in terms of sensitivity, resolution and ease of use, for applications such as thin-layer sample preparations, acceptance of various matrices (e.g. DHB for glycopeptides) and MALDI imaging. While it is obvious that the MALDI process has some dependence on the characteristics of the laser used, it is unclear which features are the most critical in determining laser performance for MALDI. In this paper we show, for the first time, that a spatially structured laser beam profile in lieu of a Gaussian profile is of striking importance. This result enabled us to design diode-pumped Nd : YAG lasers that on various critical applications perform as well for MALDI as the nitrogen lasers and in some respects even better. The modulation of the beam profile appears to be a new parameter for optimizing the MALDI process. In addition, the results trigger new questions directing us to a better understanding of the MALDI process. Copyright (c) 2006 John Wiley & Sons, Ltd.

SU-E-T-781: Using An Electronic Portal Imaging Device (EPID) for Correlating Linac Photon Beam Energies

Energy Technology Data Exchange (ETDEWEB)

Yaddanapudi, S; Cai, B; Sun, B; Noel, C; Goddu, S; Mutic, S [Washington University School of Medicine, Saint Louis, MO (United States)

2015-06-15

Purpose: Electronic portal imaging devices (EPIDs) have proven to be useful for measuring several parameters of interest in linear accelerator (linac) quality assurance (QA). The purpose of this project was to evaluate the feasibility of using EPIDs for determining linac photon beam energies. Methods: Two non-clinical Varian TrueBeam linacs (Varian Medical Systems, Palo Alto, CA) with 6MV and 10MV photon beams were used to perform the measurements. The linacs were equipped with an amorphous silicon based EPIDs (aSi1000) that were used for the measurements. We compared the use of flatness versus percent depth dose (PDD) for predicting changes in linac photon beam energy. PDD was measured in 1D water tank (Sun Nuclear Corporation, Melbourne FL) and the profiles were measured using 2D ion-chamber array (IC-Profiler, Sun Nuclear) and the EPID. Energy changes were accomplished by varying the bending magnet current (BMC). The evaluated energies conformed with the AAPM TG142 tolerance of ±1% change in PDD. Results: BMC changes correlating with a ±1% change in PDD corresponded with a change in flatness of ∼1% to 2% from baseline values on the EPID. IC Profiler flatness values had the same correlation. We observed a similar trend for the 10MV beam energy changes. Our measurements indicated a strong correlation between changes in linac photon beam energy and changes in flatness. For all machines and energies, beam energy changes produced change in the uniformity (AAPM TG-142), varying from ∼1% to 2.5%. Conclusions: EPID image analysis of beam profiles can be used to determine linac photon beam energy changes. Flatness-based metrics or uniformity as defined by AAPM TG-142 were found to be more sensitive to linac photon beam energy changes than PDD. Research funding provided by Varian Medical Systems. Dr. Sasa Mutic receives compensation for providing patient safety training services from Varian Medical Systems, the sponsor of this study.

Assessment of dye distribution in sensitized solar cells by microprobe techniques

Energy Technology Data Exchange (ETDEWEB)

Barreiros, M.A., E-mail: alexandra.barreiros@lneg.pt [Laboratório Nacional de Energia e Geologia, LEN/UES, Estrada do Paço do Lumiar, 22, 1649-038 Lisboa (Portugal); Corregidor, V. [IPFN, Instituto Superior Técnico, Universidade de Lisboa, E.N. 10, 2686-953 Sacavém (Portugal); Alves, L.C. [C2TN, Campus Tecnológico e Nuclear, Instituto Superior Técnico, Universidade de Lisboa, E.N. 10, 2686-953 Sacavém (Portugal); Guimarães, F. [Laboratório Nacional de Energia e Geologia, LGM/UCTM, Rua da Amieira, Apartado 1089, 4466-901 S. Mamede de Infesta (Portugal); Mascarenhas, J.; Torres, E.; Brites, M.J. [Laboratório Nacional de Energia e Geologia, LEN/UES, Estrada do Paço do Lumiar, 22, 1649-038 Lisboa (Portugal)

2015-04-01

Dye sensitized solar cells (DSCs) have received considerable attention once this technology offers economic and environmental advantages over conventional photovoltaic (PV) devices. The PV performance of a DSC relies on the characteristics of its photoanode, which typically consists of a nanocrystalline porous TiO{sub 2} film, enabled with a large adsorptive surface area. Dye molecules that capture photons from light during device operation are attached to the film nanoparticles. The effective loading of the dye in the TiO{sub 2} electrode is of paramount relevance for controlling and optimizing solar cell parameters. Relatively few methods are known today for quantitative evaluation of the total dye adsorbed on the film. In this context, microprobe techniques come out as suitable tools to evaluate the dye surface distribution and depth profile in sensitized films. Electron Probe Microanalysis (EPMA) and Ion Beam Analytical (IBA) techniques using a micro-ion beam were used to quantify and to study the distribution of the Ru organometallic dye in TiO{sub 2} films, making use of the different penetration depth and beam sizes of each technique. Different 1D nanostructured TiO{sub 2} films were prepared, morphologically characterized by SEM, sensitized and analyzed by the referred techniques. Dye load evaluation in different TiO{sub 2} films by three different techniques (PIXE, RBS and EPMA/WDS) provided similar results of Ru/Ti mass fraction ratio. Moreover, it was possible to assess dye surface distribution and its depth profile, by means of Ru signal, and to visualize the dye distribution in sample cross-section through X-ray mapping by EPMA/EDS. PIXE maps of Ru and Ti indicated an homogeneous surface distribution. The assessment of Ru depth profile by RBS showed that some films have homogeneous Ru depth distribution while others present different Ru concentration in the top layer (2 μm thickness). These results are consistent with the EPMA/EDS maps obtained.

The profile of the electron beam in the PTB synchrotron, and its influence on radiometric measurements with synchrotron radiation

International Nuclear Information System (INIS)

Kaase, H.

1976-01-01

A simple method is described to determine the beam profile in an electron synchrotron; the measured results are compared with calculated values. Moreover, the influence of synchrotron- and betatron-oscillations on synchrotron radiation measurements is discussed, and a method is given to correct this. (orig.) [de

Elemental depth profiles and plasma etching rates of positive-tone electron beam resists after sequential infiltration synthesis of alumina

Science.gov (United States)

Ozaki, Yuki; Ito, Shunya; Hiroshiba, Nobuya; Nakamura, Takahiro; Nakagawa, Masaru

2018-06-01

By scanning transmission electron microscopy and energy dispersive X-ray spectroscopy (STEM–EDS), we investigated the elemental depth profiles of organic electron beam resist films after the sequential infiltration synthesis (SIS) of inorganic alumina. Although a 40-nm-thick poly(methyl methacrylate) (PMMA) film was entirely hybridized with alumina, an uneven distribution was observed near the interface between the substrate and the resist as well as near the resist surface. The uneven distribution was observed around the center of a 100-nm-thick PMMA film. The thicknesses of the PMMA and CSAR62 resist films decreased almost linearly as functions of plasma etching period. The comparison of etching rate among oxygen reactive ion etching, C3F8 reactive ion beam etching (RIBE), and Ar ion beam milling suggested that the SIS treatment enhanced the etching resistance of the electron beam resists to chemical reactions rather than to ion collisions. We proposed oxygen- and Ar-assisted C3F8 RIBE for the fabrication of silica imprint molds by electron beam lithography.

Online diagnoses of high current-density beams

International Nuclear Information System (INIS)

Gilpatrick, J.D.

1994-01-01

Los Alamos National Laboratory has proposed several CW-proton-beam facilities for production of tritium or transmutation of nuclear waste with beam-current densities greater than 5 mA/mm 2 . The primary beam-diagnostics-instrumentation requirement for these facilities is provision of sufficient beam information to understand and minimize beam-loss. To accomplish this task, the beam-diagnostics instrumentation must measure beam parameters such as the centroids and profiles, total integrated current, and particle loss. Noninterceptive techniques must be used for diagnosis of high-intensity CW beam at low energies due to the large quantity of power deposited in an interceptive diagnostic device by the beam. Transverse and longitudinal centroid measurements have been developed for bunched beams by measuring and processing image currents on the accelerator walls. Transverse beam-profile measurement-techniques have also been developed using the interaction of the particle beam with the background gases near the beam region. This paper will discuss these noninterceptive diagnostic Techniques

Visualization and analysis of pulsed ion beam energy density profile with infrared imaging

Science.gov (United States)

Isakova, Y. I.; Pushkarev, A. I.

2018-03-01

Infrared imaging technique was used as a surface temperature-mapping tool to characterize the energy density distribution of intense pulsed ion beams on a thin metal target. The technique enables the measuring of the total ion beam energy and the energy density distribution along the cross section and allows one to optimize the operation of an ion diode and control target irradiation mode. The diagnostics was tested on the TEMP-4M accelerator at TPU, Tomsk, Russia and on the TEMP-6 accelerator at DUT, Dalian, China. The diagnostics was applied in studies of the dynamics of the target cooling in vacuum after irradiation and in the experiments with target ablation. Errors caused by the target ablation and target cooling during measurements have been analyzed. For Fluke Ti10 and Fluke Ti400 infrared cameras, the technique can achieve surface energy density sensitivity of 0.05 J/cm2 and spatial resolution of 1-2 mm. The thermal imaging diagnostics does not require expensive consumed materials. The measurement time does not exceed 0.1 s; therefore, this diagnostics can be used for the prompt evaluation of the energy density distribution of a pulsed ion beam and during automation of the irradiation process.

Second-harmonic generation of practical Bessel beams

Science.gov (United States)

Huang, Jin H.; Ding, Desheng; Hsu, Yin-Sung

2009-11-01

A fast Gaussian expansion approach is used to investigate fundamental and second-harmonic generation in practical Bessel beams of finite aperture. The analysis is based on the integral solutions of the KZK equation under the quasilinear approximation. The influence of the medium's attenuation on the beam profile is considered. Analysis results show that the absorption parameter has a significant effect on the far-field beam profile of the second harmonic. Under certain circumstances, the second harmonic of a practical Bessel beam still has the main properties of an ideal Bessel beam of infinite aperture when it propagates within its depth of field.

Position sensitive detection coupled to high-resolution time-of-flight mass spectrometry: Imaging for molecular beam deflection experiments

International Nuclear Information System (INIS)

Abd El Rahim, M.; Antoine, R.; Arnaud, L.; Barbaire, M.; Broyer, M.; Clavier, Ch.; Compagnon, I.; Dugourd, Ph.; Maurelli, J.; Rayane, D.

2004-01-01

We have developed and tested a high-resolution time-of-flight mass spectrometer coupled to a position sensitive detector for molecular beam deflection experiments. The major achievement of this new spectrometer is to provide a three-dimensional imaging (X and Y positions and time-of-flight) of the ion packet on the detector, with a high acquisition rate and a high resolution on both the mass and the position. The calibration of the experimental setup and its application to molecular beam deflection experiments are discussed

Suppression of dilution in Ni-Cr-Si-B alloy cladding layer by controlling diode laser beam profile

Science.gov (United States)

Tanigawa, Daichi; Funada, Yoshinori; Abe, Nobuyuki; Tsukamoto, Masahiro; Hayashi, Yoshihiko; Yamazaki, Hiroyuki; Tatsumi, Yoshihiro; Yoneyama, Mikio

2018-02-01

A Ni-Cr-Si-B alloy layer was produced on a type 304 stainless steel plate by laser cladding. In order to produce cladding layer with smooth surface and low dilution, influence of laser beam profile on cladding layer was investigated. A laser beam with a constant spatial intensity at the focus spot was used to suppress droplet formation during the cladding layer formation. This line spot, formed with a focussing unit designed by our group, suppressed droplet generation. The layer formed using this line spot with a constant spatial intensity had a much smoother surface compared to a layer formed using a line spot with a Gaussian-like beam. In addition, the dilution of the former layer was much smaller. These results indicated that a line spot with a constant spatial intensity was more effective in producing a cladding layer with smooth surface and low dilution because it suppressed droplet generation.

Beam diagnostics based on virtual instrument technology for HLS

International Nuclear Information System (INIS)

Sun Baogen; Lu Ping; Wang Xiaohui; Wang Baoyun; Wang Junhua; Gu Liming; Fang Jia; Ma Tianji

2009-01-01

The paper introduce the beam diagnostics system using virtual instrument technology for Hefei Light Source (HLS), which includes a GPIB bus-based DCCT measurement system to measure the beam DC current and beam life, a VXIbus-based closed orbit measurement system to measure the beam position, a PCIbus-based beam profile measurement system to measure the beam profile and emittance, a GPIB-LAN based bunch length system using photoelectric method, and a Ethernet-based photon beam position measurement system. The software is programmed by LabVIEW, which reduces much developing work. (authors)

Beam properties and stability of a flattening-filter free 7 MV beam--An overview

International Nuclear Information System (INIS)

Dzierma, Yvonne; Licht, Norbert; Nuesken, Frank; Ruebe, Christian

2012-01-01

Purpose: Several works have recently focused on flattening-filter-free (FFF) beams of linear accelerators of various companies (in particular, Varian and Elekta), but no overview as yet exists for the flattening-filter free 7XU beam (Siemens Artiste). Methods: Dosimetric properties of the 7XU beam were measured in May and September 2011. We present depth dose curves and beam profiles, output factors, and MLC transmission and assess the stability of the measurements. The 7XU beam was commissioned in the Pinnacle³ treatment planning system (TPS), and modeling results including the spectrum are presented. Results: The percent depth dose curve of the 7XU beam is similar to the flat 6X beam line, with a slightly smaller surface dose. The beam profiles show the characteristic shape of flattening-filter free beams, with deviations between measurements of generally less than 1%. The output factors of the 7XU beam decrease more slowly than for the 6X beam. The MLC transmission is comparable but slightly less for the 7XU beam. The 7XU beam can be adequately modeled by the Pinnacle³ TPS, with successful dosimetric verification. The spectrum of the 7XU beam has lower photon fluence up to approximately 2.5 MeV and higher fluence beyond, with a slightly higher mean energy. Conclusions: The 7XU beam has been commissioned for clinical use after successful modeling, stability checks, and dosimetric verification.

Intra-beam Scattering Theory and RHIC Experiments

International Nuclear Information System (INIS)

Wei, J.; Fedotov, A.; Fischer, W.; Malitsky, N.; Parzen, G.; Qiang, J.

2005-01-01

Intra-beam scattering is the leading mechanism limiting the luminosity in heavy-ion storage rings like the Relativistic Heavy Ion Collider (RHIC). The multiple Coulomb scattering among the charged particles causes transverse emittance growth and longitudinal beam de-bunching and beam loss, compromising machine performance during collision. Theoretically, the original theories developed by Piwinski, Bjorken, and Mtingwa only describe the rms beam size growth of an unbounded Gaussian distribution. Equations based on the Fokker-Planck approach are developed to further describe the beam density profile evolution and beam loss. During the 2004 RHIC heavy-ion operation, dedicated IBS experiments were performed to bench-mark the rms beam size growth, beam loss, and profile evolution both for a Gaussian-like and a longitudinal hollow beam. This paper summarizes the IBS theory and discusses the experimental bench-marking results

Heavy ion beam probe development for the plasma potential measurement on the TUMAN-3M tokamak

International Nuclear Information System (INIS)

Askinazi, L.G.; Kornev, V.A.; Lebedev, S.V.; Tukachinsky, A.S.; Zhubr, N.A.; Dreval, N.B.; Krupnik, L.I.

2004-01-01

The peculiarities of the heavy ion beam probe implementation on the small aspect ratio tokamak TUMAN-3M are analyzed. The toroidal displacement of beam trajectory due to the high I pl /B tor ratio is taken into account when designing the layout of the diagnostic. Numerical calculation of beam trajectories using realistic configuration of TUMAN-3M magnetic fields and parabolic plasma current profile resulted in proper adjustment of probing and detection parameters (probing ion material, energy, entrance angles, detector location, and orientation). Secondary ion energy analyzer gain functions G and F were measured in situ using neutral hydrogen puffed in the tokamak vessel as a target for secondary ions production. The detector unit featured split-plate design and had additional electrodes for secondary electron emission suppression. As a result, the diagnostic is now capable of plasma potential evolution measurement and is sensitive enough to trace the potential profile evolution at the L-H mode transition

The Sensitivity Analysis of Axial Pressure Tube Creep Profile for Dryout Power in PHWR

Energy Technology Data Exchange (ETDEWEB)

Ryu, Euiseung; Kim, Youngae [KHNP CRI, Daejeon (Korea, Republic of)

2016-10-15

The Stern Laboratory performed the CHF tests with only one axial pressure tube creep profile per 3.3%, 5.1% peak crept channel and made CHF correlation including creep factor from the CHF test results. Wolsong nuclear power plants also have utilized the same CHF correlation derived by CNL. Pressure tube diameter creep rate is function of fast neutron, coolant temperature, and coolant pressure in a channel. It means that various axial pressure tube creep profiles exist in PHWR due to the history of operating conditions. Usually, CHF correlation is used during ROP(Regional Overpower Protection) Trip Setpoint Analysis or Safety Analysis in PHWR. The sensitivity analysis for CHF effects using various creep profiles is needed. This paper summarizes the comparison results of dryout power between CHF test creep profile and estimated creep profiles of Wolsong units. The effect of axial pressure tube creep profile for dryout power in fuel channel is evaluated by using Stern Lab. CHF test creep profile and 380 channel creep profiles of Wolsong. The dryout powers at 3.3% and 5.1% test conditions are slightly smaller when using 380 Wolsong channels creep profiles. These also show that the simulated dryout powers maintain consistency regardless of flow conditions.

SPIDER beam dump as diagnostic of the particle beam

Energy Technology Data Exchange (ETDEWEB)

Zaupa, M., E-mail: matteo.zaupa@igi.cnr.it; Sartori, E. [Università degli Studi di Padova, Via 8 Febbraio 2, Padova 35122 (Italy); Consorzio RFX, Corso Stati Uniti 4, Padova 35127 (Italy); Dalla Palma, M.; Brombin, M.; Pasqualotto, R. [Consorzio RFX, Corso Stati Uniti 4, Padova 35127 (Italy)

2016-11-15

The beam power produced by the negative ion source for the production of ion of deuterium extracted from RF plasma is mainly absorbed by the beam dump component which has been designed also for measuring the temperatures on the dumping panels for beam diagnostics. A finite element code has been developed to characterize, by thermo-hydraulic analysis, the sensitivity of the beam dump to the different beam parameters. The results prove the capability of diagnosing the beam divergence and the horizontal misalignment, while the entity of the halo fraction appears hardly detectable without considering the other foreseen diagnostics like tomography and beam emission spectroscopy.

A beam position monitor for low current dc beams

International Nuclear Information System (INIS)

Adderley, P.; Barry, W.; Heefner, J.; Kloeppel, P.; Rossmanith, R.; Wise, M.; Jachim, S.

1989-01-01

The 4 GeV recirculating linac, CEBAF, if presently under construction and will produce a CW beam with average current between.1 and 200 μA. In order to measure beam position, the beam current will be amplitude modulated at a frequency of 10 MHz. The modulation is detected by an inductive loop type monitor with electronics sensitive only to the modulation frequency. The first test with beam from the CEBAF injector indicate that beam position can be measured with an accuracy of .1 mm at a modulated beam current of 1 μA. 1 ref., 6 figs., 1 tab

High-brightness electron beam diagnostics at the ATF

International Nuclear Information System (INIS)

Wang, X.J.; Ben-Zvi, I.

1996-01-01

The Brookhaven Accelerator Test Facility (ATF) is a dedicated user facility for accelerator physicists. Its design is optimized to explore laser acceleration and coherent radiation production. To characterize the low-emittance, picoseconds long electron beam produced by the ATF's photocathode RF gun, we have installed electron beam profile monitors for transverse emittance measurement, and developed a new technique to measure electron beam pulse length by chirping the electron beam energy. We have also developed a new technique to measure the ps slice emittance of a 10 ps long electron beam. Stripline beam position monitors were installed along the beam to monitor the electron beam position and intensity. A stripline beam position monitor was also used to monitor the timing jitter between the RF system and laser pulses. Transition radiation was used to measure electron beam energy, beam profile and electron beam bunch length

A Prototype Ionization Profile Monitor for RHIC

Energy Technology Data Exchange (ETDEWEB)

Connolly, R. [Brookhaven National Lab. (BNL), Upton, NY (United States); Cameron, P. [Brookhaven National Lab. (BNL), Upton, NY (United States); Ryan, W. [Brookhaven National Lab. (BNL), Upton, NY (United States); Shea, T. [Brookhaven National Lab. (BNL), Upton, NY (United States); Sikora, R. [Brookhaven National Lab. (BNL), Upton, NY (United States); Tsoupas, N. [Brookhaven National Lab. (BNL), Upton, NY (United States)

1997-03-17

The Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Lab will accelerate and store beams of ions ranging from protons to gold nuclei. Transverse beam profiles will be obtained by measuring the distribution of free electrons formed by beam ionization of the residual gas. The electrons are swept from the beamline by a transverse electric field, amplified by a microchannel plate (MCP), and collected on a circuit board with strip anodes oriented parallel to the beam axis. A uniform magnetic field,parallel to the sweep electric field, counters the defocusing effects of space charge and recoil momentum. A single-plane prototype ionization profile montor (IPM) was installed near the end of the AGS-to-RHIC transfer line (ATR) and tested during the sextant commissioning rung. It measured vertical profiles of single bunches of Au nuclei with intensities of 0.6-1.0 x 10⁸ particles. These profiles are compared to profiles on a fluorescent screen (WF3) located 2m downstream from the IPM. This paper describes the detector and gives results from the beam test.

Temperature profiles induced by a stationary CW laser beam in a multi-layer structure: application to solar cell interconnect welding

Energy Technology Data Exchange (ETDEWEB)

Oh, J.E.; Ianno, N.J.; Ahmed, A.U.

1985-01-01

A three-dimensional heat transfer model for heating of a multilayer structure by a stationary Gaussian CW CO/sub 2/ laser beam is developed and applied to solar cell interconnect welding. This model takes into account the temperature dependence of the thermal conductivity and diffusivity as well as free carrier absorption of the incident beam in the silicon where appropriate. Finally, the theoretical temperature profiles are used to determine the weld spot size and these values are compared to results obtained from a simple welding experiment, where excellent agreement is obtained. 18 references, 13 figures.

Beam transport

International Nuclear Information System (INIS)

1988-01-01

Considerable experience has now been gained with the various beam transport lines, and a number of minor changes have been made to improve the ease of operation. These include: replacement of certain little-used slits by profile monitors (harps or scanners); relocation of steering magnets, closer to diagnostic harps or profile scanners; installation of a scanner inside the isocentric neutron therapy system; and conversion of a 2-doublet quadrupole telescope (on the neutron therapy beamline) to a 2-triplet telescope. The beam-swinger project has been delayed by very late delivery of the magnet iron to the manufacturer, but is now progressing smoothly. The K=600 spectrometer magnets have now been delivered and are being assembled for field mapping. The x,y-table with its associated mapping equipment is complete, together with the driver software. One of the experimental areas has been dedicated to the production of collimated neutron beams and has been equipped with a bending magnet and beam dump, together with steel collimators fixed at 4 degrees intervals from 0 degrees to 16 degrees. Changes to the target cooling and shielding system for isotope production have led to a request for much smaller beam spot sizes on target, and preparations have been made for rearrangement of the isotope beamline to permit installation of quadrupole triplets on the three beamlines after the switching magnet. A practical system of quadrupoles for matching beam properties to the spectrometer has been designed. 6 figs

Optical fiber designs for beam shaping

Science.gov (United States)

Farley, Kevin; Conroy, Michael; Wang, Chih-Hao; Abramczyk, Jaroslaw; Campbell, Stuart; Oulundsen, George; Tankala, Kanishka

2014-03-01

A large number of power delivery applications for optical fibers require beams with very specific output intensity profiles; in particular applications that require a focused high intensity beam typically image the near field (NF) intensity distribution at the exit surface of an optical fiber. In this work we discuss optical fiber designs that shape the output beam profile to more closely correspond to what is required in many real world industrial applications. Specifically we present results demonstrating the ability to transform Gaussian beams to shapes required for industrial applications and how that relates to system parameters such as beam product parameter (BPP) values. We report on the how different waveguide structures perform in the NF and show results on how to achieve flat-top with circular outputs.

Antimicrobial sensitivity profile of Staphylococcus spp. Isolated from clinical mastitis

Directory of Open Access Journals (Sweden)

Thamires Martins

2012-12-01

Full Text Available Inflammation of the mammary gland, which is also known as mastitis, occupies a prominent place among the diseases that affect dairy cattle, having a great economic importance in the dairy sector. Mastitis may have different origins, however, infectious mastitis is the most frequent and represents a risk to public health due to the propagation of microorganisms through milk. Staphylococcus spp. are considered the microorganisms that cause the greatest losses in milk production, being that Staphylococcus aureus is the pathogen of major importance because they present high resistence to antimicrobials. Empirical treatment, without prior identification of the pathogens and their resistance profile, may contribute to the emergence of multidrug-resistant strains and risk the efficiency of the antimicrobial. In that scenery, the study aimed to evaluate the resistance profile of Staphylococcus spp. against some antimicrobials used in the treatment of cows with clinical mastitis. The study was conducted on a property in the state of São Paulo from January 2011 to June 2012. We evaluated 29 lactating cows that present clinical mastitis in, at least, one mammary quarter. The diagnosis of clinical mastitis was performed by evaluating the clinical signs and also by Tamis test. Samples of milk from mammary quarters were collected aseptically in sterile tubes for microbiological evaluation. Microorganisms were isolated on sheep blood agar 5% and Sabouraud agar with chloramphenicol. The sensitivity profile of Staphylococcus spp. to the antibiotics ampicillin, cephalexin, ceftiofur, cefaclor, gentamicin, kanamycin, neomycin, penicillin G and oxacillin, was tested by disk diffusion test on Mueller-Hinton agar. From a total of 106 samples of milk analyzed, 64 (60.38% presented microbiological growth, being observed isolation of Streptococcus spp. 29 (34.52%, Staphylococcus spp. 28 (33.33%, Corynebacterium spp. 17 (20.24%, filamentous fungi 4 (4.76%, yeast 4 (4

The Impact of Beam Deposition on Bootstrap Current of Fast Ion Produced by Neutral Beam Tangential Injection

International Nuclear Information System (INIS)

Huang Qian-Hong; Gong Xue-Yu; Lu Xing-Qiang; Yu Jun; Cao Jin-Jia

2015-01-01

The density profile of fast ions arising from a tangentially injected diffuse neutral beam in tokamak plasma is calculated. The effects of mean free paths and beam tangency radius on the density profile are discussed under typical HL-2A plasmas parameters. The results show that the profile of fast ions is strongly peaked at the center of the plasma when the mean free path at the maximum deuteron density is larger than the minor radius, while the peak value decreases when the mean free path at the maximum deuteron density is larger than twice that of the minor radius due to the beam transmission loss. Moreover, the bootstrap current of fast ions for various mean free paths at the maximum deuteron density is calculated and its density is proved to be closely related to the deposition of the neutral beam. With the electron return current considered, the net current density obviously decreases. Meanwhile, the peak central fast ion density increases when the beam tangency radius approaches the major radius, and the net bootstrap current increases rapidly with the increasing beam tangency radius. (paper)

MethylMeter(®): bisulfite-free quantitative and sensitive DNA methylation profiling and mutation detection in FFPE samples.

Science.gov (United States)

McCarthy, David; Pulverer, Walter; Weinhaeusel, Andreas; Diago, Oscar R; Hogan, Daniel J; Ostertag, Derek; Hanna, Michelle M

2016-06-01

Development of a sensitive method for DNA methylation profiling and associated mutation detection in clinical samples. Formalin-fixed and paraffin-embedded tumors received by clinical laboratories often contain insufficient DNA for analysis with bisulfite or methylation sensitive restriction enzymes-based methods. To increase sensitivity, methyl-CpG DNA capture and Coupled Abscription PCR Signaling detection were combined in a new assay, MethylMeter(®). Gliomas were analyzed for MGMT methylation, glioma CpG island methylator phenotype and IDH1 R132H. MethylMeter had 100% assay success rate measuring all five biomarkers in formalin-fixed and paraffin-embedded tissue. MGMT methylation results were supported by survival and mRNA expression data. MethylMeter is a sensitive and quantitative method for multitarget DNA methylation profiling and associated mutation detection. The MethylMeter-based GliomaSTRAT assay measures methylation of four targets and one mutation to simultaneously grade gliomas and predict their response to temozolomide. This information is clinically valuable in management of gliomas.

Beam position monitor for energy recovered linac beams

Energy Technology Data Exchange (ETDEWEB)

Powers, Thomas; Evtushenko, Pavel

2017-06-06

A method of determining the beam position in an energy recovered linac (ERL). The method makes use of in phase and quadrature (I/Q) demodulation techniques to separate the pickup signal generated by the electromagnetic fields generated by the first and second pass beam in the energy recovered linac. The method includes using analog or digital based I/Q demodulation techniques in order to measure the relative amplitude of the signals from a position sensitive beam pickup such as a button, strip line or microstripline beam position monitor.

Study on the beam transport from the Bio-Nano ECRIS

Energy Technology Data Exchange (ETDEWEB)

Uchida, T. [Bio-Nano Electronics Research Centre, Toyo University, 2100, Kujirai, Kawagoe, Saitama 350-8585 (Japan); Minezaki, H.; Yoshida, Y. [Bio-Nano Electronics Research Centre, Toyo University, 2100, Kujirai, Kawagoe, Saitama 350-8585 (Japan); Graduate School of Engineering, Toyo University, 2100, Kujirai, Kawagoe, Saitama 350-8585 (Japan); Oshima, K. [Graduate School of Engineering, Toyo University, 2100, Kujirai, Kawagoe, Saitama 350-8585 (Japan); Racz, R.; Biri, S. [Institute of Nuclear Research (ATOMKI), H-4026 Debrecen, Bem ter 18/c (Hungary); Muramatsu, M.; Kitagawa, A. [National Institute of Radiological Sciences (NIRS), 4-9-1 Anagawa, Inage-ku, Chiba-shi, Chiba 263-8555 (Japan); Asaji, T. [Tateyama Machine Co., Ltd., 30 Shimonoban, Toyama-shi, Toyama 930-1305 (Japan); Kato, Y. [Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita-shi, Osaka 565-0871 (Japan)

2012-02-15

The beam transport of N{sup +} ion and C{sub 60}{sup +} ion in the Bio-Nano ECRIS with min-B configuration was investigated based on the ion beam profiles. The N{sup +} beam could be focused under the low-beam current conditions. Also the C{sub 60}{sup +} beam could be focused in spite of the large space-charge effect which will lead the divergence of the beam. We confirmed that our beam transport system works well even for the C{sub 60}{sup +} ion beam. We estimated the highest C{sub 60}{sup +} beam current with the focused beam profile by comparing the N{sup +} ion beam.

Computational Analysis of Epidermal Growth Factor Receptor Mutations Predicts Differential Drug Sensitivity Profiles toward Kinase Inhibitors.

Science.gov (United States)

Akula, Sravani; Kamasani, Swapna; Sivan, Sree Kanth; Manga, Vijjulatha; Vudem, Dashavantha Reddy; Kancha, Rama Krishna

2018-05-01

A significant proportion of patients with lung cancer carry mutations in the EGFR kinase domain. The presence of a deletion mutation in exon 19 or L858R point mutation in the EGFR kinase domain has been shown to cause enhanced efficacy of inhibitor treatment in patients with NSCLC. Several less frequent (uncommon) mutations in the EGFR kinase domain with potential implications in treatment response have also been reported. The role of a limited number of uncommon mutations in drug sensitivity was experimentally verified. However, a huge number of these mutations remain uncharacterized for inhibitor sensitivity or resistance. A large-scale computational analysis of clinically reported 298 point mutants of EGFR kinase domain has been performed, and drug sensitivity profiles for each mutant toward seven kinase inhibitors has been determined by molecular docking. In addition, the relative inhibitor binding affinity toward each drug as compared with that of adenosine triphosphate was calculated for each mutant. The inhibitor sensitivity profiles predicted in this study for a set of previously characterized mutants correlated well with the published clinical, experimental, and computational data. Both the single and compound mutations displayed differential inhibitor sensitivity toward first- and next-generation kinase inhibitors. The present study provides predicted drug sensitivity profiles for a large panel of uncommon EGFR mutations toward multiple inhibitors, which may help clinicians in deciding mutant-specific treatment strategies. Copyright © 2018 International Association for the Study of Lung Cancer. Published by Elsevier Inc. All rights reserved.

Analytical expression for position sensitivity of linear response beam position monitor having inter-electrode cross talk

Energy Technology Data Exchange (ETDEWEB)

Kumar, Mukesh, E-mail: mukeshk@rrcat.gov.in [Beam Diagnostics Section, Indus Operations, Beam Dynamics & Diagnostics Division, Raja Ramanna Centre for Advanced Technology, Indore, 452013 MP (India); Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai 400 094 (India); Ojha, A.; Garg, A.D.; Puntambekar, T.A. [Beam Diagnostics Section, Indus Operations, Beam Dynamics & Diagnostics Division, Raja Ramanna Centre for Advanced Technology, Indore, 452013 MP (India); Senecha, V.K. [Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai 400 094 (India); Ion Source Lab., Proton Linac & Superconducting Cavities Division, Raja Ramanna Centre for Advanced Technology, Indore, 452013 MP (India)

2017-02-01

According to the quasi electrostatic model of linear response capacitive beam position monitor (BPM), the position sensitivity of the device depends only on the aperture of the device and it is independent of processing frequency and load impedance. In practice, however, due to the inter-electrode capacitive coupling (cross talk), the actual position sensitivity of the device decreases with increasing frequency and load impedance. We have taken into account the inter-electrode capacitance to derive and propose a new analytical expression for the position sensitivity as a function of frequency and load impedance. The sensitivity of a linear response shoe-box type BPM has been obtained through simulation using CST Studio Suite to verify and confirm the validity of the new analytical equation. Good agreement between the simulation results and the new analytical expression suggest that this method can be exploited for proper designing of BPM.

Engineering the on-axis intensity of Bessel beam by a feedback tuning loop

Science.gov (United States)

Li, Runze; Yu, Xianghua; Yang, Yanlong; Peng, Tong; Yao, Baoli; Zhang, Chunmin; Ye, Tong

2018-02-01

The Bessel beam belongs to a typical class of non-diffractive optical fields that are characterized by their invariant focal profiles along the propagation direction. However, ideal Bessel beams only rigorously exist in theory; Bessel beams generated in the lab are quasi-Bessel beams with finite focal extensions and varying intensity profiles along the propagation axis. The ability to engineer the on-axis intensity profile to the desired shape is essential for many applications. Here we demonstrate an iterative optimization-based approach to engineering the on-axis intensity of Bessel beams. The genetic algorithm is used to demonstrate this approach. Starting with a traditional axicon phase mask, in the design process, the computed on-axis beam profile is fed into a feedback tuning loop of an iterative optimization process, which searches for an optimal radial phase distribution that can generate a generalized Bessel beam with the desired onaxis intensity profile. The experimental implementation involves a fine-tuning process that adjusts the originally targeted profile so that the optimization process can optimize the phase mask to yield an improved on-axis profile. Our proposed method has been demonstrated in engineering several zeroth-order Bessel beams with customized on-axis profiles. High accuracy and high energy throughput merit its use in many applications.

The role of the neutral beam fueling profile in the performance of the Tokamak Fusion Test Reactor and other tokamak plasmas

International Nuclear Information System (INIS)

Park, H.K.; Batha, S.

1997-02-01

Scalings for the stored energy and neutron yield, determined from experimental data are applied to both deuterium-only and deuterium-tritium plasmas in different neutral beam heated operational domains in Tokamak Fusion Test Reactor. The domain of the data considered includes the Supershot, High poloidal beta, Low-mode, and limiter High-mode operational regimes, as well as discharges with a reversed magnetic shear configuration. The new important parameter in the present scaling is the peakedness of the heating beam fueling profile shape. Ion energy confinement and neutron production are relatively insensitive to other plasma parameters compared to the beam fueling peakedness parameter and the heating beam power when considering plasmas that are stable to magnetohydrodynamic modes. However, the stored energy of the electrons is independent of the beam fueling peakedness. The implication of the scalings based on this parameter is related to theoretical transport models such as radial electric field shear and Ion Temperature Gradient marginality models. Similar physics interpretation is provided for beam heated discharges on other major tokamaks

Revealing the radial modes in vortex beams

CSIR Research Space (South Africa)

Sephton, Bereneice C

2016-10-01

Full Text Available Light beams that carry orbital angular momentum are often approximated by modulating an initial beam, usually Gaussian, with an azimuthal phase variation to create a vortex beam. Such vortex beams are well defined azimuthally, but the radial profile...

A new, simple and precise method for measuring cyclotron proton beam energies using the activity vs. depth profile of zinc-65 in a thick target of stacked copper foils

International Nuclear Information System (INIS)

Asad, A.H.; Chan, S.; Cryer, D.; Burrage, J.W.; Siddiqui, S.A.; Price, R.I.

2015-01-01

The proton beam energy of an isochronous 18 MeV cyclotron was determined using a novel version of the stacked copper-foils technique. This simple method used stacked foils of natural copper forming ‘thick’ targets to produce Zn radioisotopes by the well-documented (p,x) monitor-reactions. Primary beam energy was calculated using the "6"5Zn activity vs. depth profile in the target, with the results obtained using "6"2Zn and "6"3Zn (as comparators) in close agreement. Results from separate measurements using foil thicknesses of 100, 75, 50 or 25 µm to form the stacks also concurred closely. Energy was determined by iterative least-squares comparison of the normalized measured activity profile in a target-stack with the equivalent calculated normalized profile, using ‘energy’ as the regression variable. The technique exploits the uniqueness of the shape of the activity vs. depth profile of the monitor isotope in the target stack for a specified incident energy. The energy using "6"5Zn activity profiles and 50-μm foils alone was 18.03±0.02 [SD] MeV (95%CI=17.98–18.08), and 18.06±0.12 MeV (95%CI=18.02–18.10; NS) when combining results from all isotopes and foil thicknesses. When the beam energy was re-measured using "6"5Zn and 50-μm foils only, following a major upgrade of the ion sources and nonmagnetic beam controls the results were 18.11±0.05 MeV (95%CI=18.00–18.23; NS compared with ‘before’). Since measurement of only one Zn monitor isotope is required to determine the normalized activity profile this indirect yet precise technique does not require a direct beam-current measurement or a gamma-spectroscopy efficiency calibrated with standard sources, though a characteristic photopeak must be identified. It has some advantages over published methods using the ratio of cross sections of monitor reactions, including the ability to determine energies across a broader range and without need for customized beam degraders. - Highlights: • Simple

Diagnostics for high-brightness beams

International Nuclear Information System (INIS)

Shafer, R.E.

1990-01-01

Special techniques are required for beam diagnostics on high-brightness particle beams. Examples of high-brightness beams include low-emittance proton linacs (either pulsed or CW), electron linacs suitable for free-electron-laser applications, and future linear colliders. Non-interceptive and minimally-interceptive techniques for measuring beam current, position, profile, and transverse and longitudinal emittance will be reviewed. Included will be stripline, wire scanner, laser neutralization, beam-beam scattering, interceptive microgratings, spontaneous emission, optical transition radiation, and other techniques. 24 refs

Development of neutral beam source using electron beam excited plasma

International Nuclear Information System (INIS)

Hara, Yasuhiro; Hamagaki, Manabu; Mise, Takaya; Hara, Tamio

2011-01-01

A low-energy neutral beam (NB) source, which consists of an electron-beam-excited plasma (EBEP) source and two carbon electrodes, has been developed for damageless etching of ultra-large-scale integrated (ULSI) devices. It has been confirmed that the Ar ion beam energy was controlled by the acceleration voltage and the beam profile had good uniformity over the diameter of 80 mm. Dry etching of a Si wafer at the floating potential has been carried out by Ar NB. Si sputtering yield by an Ar NB clearly depends on the acceleration voltage. This result shows that the NB has been generated through the charge exchange reaction from the ion beam in the process chamber. (author)

Video profile monitor diagnostic system for GTA

International Nuclear Information System (INIS)

Sandoval, D.P.; Garcia, R.C.; Gilpatrick, J.D.; Johnson, K.F.; Shinas, M.A.; Wright, R.; Yuan, V.; Zander, M.E.

1992-01-01

This paper describes a video diagnostic system used to measure the beam profile and position of the Ground Test Accelerator 2.5-MeV H - ion beam as it exits the intermediate matching section. Inelastic collisions between H-ions and residual nitrogen to fluoresce. The resulting light is captured through transport optics by an intensified CCD camera and is digitized. Real-time beam-profile images are displayed and stored for detailed analysis. Analyzed data showing resolutions for both position and profile measurements will also be presented

Detection of coherent beam-beam modes with digitized beam position monitor signals

CERN Document Server

Stancari, G.; White, S.M.

2014-01-01

A system for bunch-by-bunch detection of transverse proton and antiproton coherent oscillations in the Fermilab Tevatron collider is described. It is based on the signal from a single beam-position monitor located in a region of the ring with large amplitude functions. The signal is digitized over a large number of turns and Fourier-analyzed offline with a dedicated algorithm. To enhance the signal, band-limited noise is applied to the beam for about 1 s. This excitation does not adversely affect the circulating beams even at high luminosities. The device has a response time of a few seconds, a frequency resolution of $1.6\\times 10^{-5}$ in fractional tune, and it is sensitive to oscillation amplitudes of 60 nm. It complements Schottky detectors as a diagnostic tool for tunes, tune spreads, and beam-beam effects. Measurements of coherent mode spectra are presented and compared with models of beam-beam oscillations.

Estimation of beam material random field properties via sensitivity-based model updating using experimental frequency response functions

Science.gov (United States)

Machado, M. R.; Adhikari, S.; Dos Santos, J. M. C.; Arruda, J. R. F.

2018-03-01

Structural parameter estimation is affected not only by measurement noise but also by unknown uncertainties which are present in the system. Deterministic structural model updating methods minimise the difference between experimentally measured data and computational prediction. Sensitivity-based methods are very efficient in solving structural model updating problems. Material and geometrical parameters of the structure such as Poisson's ratio, Young's modulus, mass density, modal damping, etc. are usually considered deterministic and homogeneous. In this paper, the distributed and non-homogeneous characteristics of these parameters are considered in the model updating. The parameters are taken as spatially correlated random fields and are expanded in a spectral Karhunen-Loève (KL) decomposition. Using the KL expansion, the spectral dynamic stiffness matrix of the beam is expanded as a series in terms of discretized parameters, which can be estimated using sensitivity-based model updating techniques. Numerical and experimental tests involving a beam with distributed bending rigidity and mass density are used to verify the proposed method. This extension of standard model updating procedures can enhance the dynamic description of structural dynamic models.

Optimizing laser beam profiles using micro-lens arrays for efficient material processing: applications to solar cells

Science.gov (United States)

Hauschild, Dirk; Homburg, Oliver; Mitra, Thomas; Ivanenko, Mikhail; Jarczynski, Manfred; Meinschien, Jens; Bayer, Andreas; Lissotschenko, Vitalij

2009-02-01

High power laser sources are used in various production tools for microelectronic products and solar cells, including the applications annealing, lithography, edge isolation as well as dicing and patterning. Besides the right choice of the laser source suitable high performance optics for generating the appropriate beam profile and intensity distribution are of high importance for the right processing speed, quality and yield. For industrial applications equally important is an adequate understanding of the physics of the light-matter interaction behind the process. In advance simulations of the tool performance can minimize technical and financial risk as well as lead times for prototyping and introduction into series production. LIMO has developed its own software founded on the Maxwell equations taking into account all important physical aspects of the laser based process: the light source, the beam shaping optical system and the light-matter interaction. Based on this knowledge together with a unique free-form micro-lens array production technology and patented micro-optics beam shaping designs a number of novel solar cell production tool sub-systems have been built. The basic functionalities, design principles and performance results are presented with a special emphasis on resilience, cost reduction and process reliability.

Recent improvements in beam diagnostic instrumentation

International Nuclear Information System (INIS)

Sander, O.R.; Jameson, R.A.; Patton, R.D.

1979-01-01

In high-current machines, such as LAMPF and the envisioned Hanford Engineering Development Laboratory (HEDL) Fusion Materials Irradiation Test (FMIT) Facility linac, hands-on maintenance is desired Beam spill must be kept extremely low; therefore, attention must be given to beam fringes (tails). Beam matching to the structure becomes increasingly important. Equipment capable of accurately measuring transverse beam profiles over a range spanning more than four orders of magnitude and longitudinal phase profiles over ranges spanning more than three orders of magnitude is described. Errors in 100-MeV transverse emittance measurements are explored and experimental emittance measurements made with three different methods are compared. Advantages of one nondestructive method are developed

Generalized beam quality factor of aberrated truncated Gaussian laser beams

CSIR Research Space (South Africa)

Mafusire, C

2011-07-01

Full Text Available with a quadratic refractive index profile, a change in the beam quality factor can be used to infer the pre- sence of aberrations and thereby study the media of interest. For these reasons, among others, research into the beam qual- ity factor... very much like a normal lens (without the rotational symmetry associated with defocus) since the beam quality factor is calculated in the principal axes. With y-astigmatism, the lenslike behavior does not take place in the principal axes where...

Beam-beam interaction in high energy linear electron-positron colliders

International Nuclear Information System (INIS)

Ritter, S.

1985-04-01

The interaction of high energy electron and positron beams in a linear collider has been investigated using a macroparticle Monte Carlo method based on a Cloud-In-Cells plasma simulation scheme. Density evolutions, luminosities, energy and angular distributions for electrons (positrons) and synchrotron photons are calculated. Beside beams with a symmetric transverse profile also flat beams are considered. A reasonably good agreement to alternative computer calculations as well as to an analytical approximation for the energy spectrum of synchrotron photons has been obtained. (author)

The application of image acquisition and processing technology in measurement of beam profile on particle accelerator

International Nuclear Information System (INIS)

Nie Zhenpeng; Zheng Yong; Shen Zhiqing; Wang Shaoming

2000-01-01

An introduction is given to the real-time measuring method which can measure the intensity and profile of the beam by a scintillator screen on HIRFL (Heavy Ion Research Facility of Lanzhou). Hardware structure is described briefly, methods of the software design are mainly presented. The system can make a dynamic analysis on the faculae image and has many advantages, such as good reliability, high precision, intuitional measurement, friendly interface of the application software etc. Finally some results of measurement are given

Squid based beam current meter

International Nuclear Information System (INIS)

Kuchnir, M.

1983-01-01

A SQUID based beam current meter has the capability of measuring the current of a beam with as little as 30 x 155 antiprotons (with a signal to noise ratio of 2). If low noise dc current is used to cancel most of the beam or an up-down counter is used to count auto-resets this sensitivity will be available at any time in the acumulation process. This current meter will therefore be a unique diagnostic tool for optimizing the performance of several Tev I components. Besides requiring liquid helium it seems that its only drawback is not to follow with the above sensitivity a sudden beam change larger than 16 μA, something that could be done using a second one in a less sensitive configuration

Sensitivity of echo enabled harmonic generation to sinusoidal electron beam energy structure

Directory of Open Access Journals (Sweden)

E. Hemsing

2017-06-01

Full Text Available We analytically examine the bunching factor spectrum of a relativistic electron beam with sinusoidal energy structure that then undergoes an echo-enabled harmonic generation (EEHG transformation to produce high harmonics. The performance is found to be described primarily by a simple scaling parameter. The dependence of the bunching amplitude on fluctuations of critical parameters is derived analytically, and compared with simulations. Where applicable, EEHG is also compared with high gain harmonic generation (HGHG and we find that EEHG is generally less sensitive to several types of energy structure. In the presence of intermediate frequency modulations like those produced by the microbunching instability, EEHG has a substantially narrower intrinsic bunching pedestal.

Characteristics of flattening filter free beams at low monitor unit settings

International Nuclear Information System (INIS)

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

2013-01-01

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 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 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 ±5%. The

Characteristics of flattening filter free beams at low monitor unit settings

Energy Technology Data Exchange (ETDEWEB)

Akino, Yuichi [Department of Radiology, Osaka University Hospital, Suita, Osaka 565-0871, Japan and Department of Radiation Oncology, Osaka University Graduate School of Medicine, Suita, Osaka 565-0871 (Japan); Ota, Seiichi; Inoue, Shinichi; Mizuno, Hirokazu [Department of Radiology, Osaka University Hospital, Suita, Osaka 565-0871 (Japan); Sumida, Iori; Yoshioka, Yasuo; Ogawa, Kazuhiko [Department of Radiation Oncology, Osaka University Graduate School of Medicine, Suita, Osaka 565-0871 (Japan); Isohashi, Fumiaki [Oncology Center, Osaka University Hospital, Suita, Osaka 565-0871 (Japan)

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

Applications of electron lenses: scraping of high-power beams, beam-beam compensation, and nonlinear optics

Energy Technology Data Exchange (ETDEWEB)

Stancari, Giulio

2014-09-11

Electron lenses are pulsed, magnetically confined electron beams whose current-density profile is shaped to obtain the desired effect on the circulating beam. Electron lenses were used in the Fermilab Tevatron collider for bunch-by-bunch compensation of long-range beam-beam tune shifts, for removal of uncaptured particles in the abort gap, for preliminary experiments on head-on beam-beam compensation, and for the demonstration of halo scraping with hollow electron beams. Electron lenses for beam-beam compensation are being commissioned in the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory (BNL). Hollow electron beam collimation and halo control were studied as an option to complement the collimation system for the upgrades of the Large Hadron Collider (LHC) at CERN; a conceptual design was recently completed. Because of their electric charge and the absence of materials close to the proton beam, electron lenses may also provide an alternative to wires for long-range beam-beam compensation in LHC luminosity upgrade scenarios with small crossing angles. At Fermilab, we are planning to install an electron lens in the Integrable Optics Test Accelerator (IOTA, a 40-m ring for 150-MeV electrons) as one of the proof-of-principle implementations of nonlinear integrable optics to achieve large tune spreads and more stable beams without loss of dynamic aperture.

Noninterferometric phase imaging of a neutral atomic beam

International Nuclear Information System (INIS)

Fox, P.J.; Mackin, T.R.; Turner, L.D.; Colton, I.; Nugent, K.A.; Scholten, R.E.

2002-01-01

We demonstrate quantitative phase imaging of a neutral atomic beam by using a noninterferometric technique. A collimated thermal atomic beam is phase shifted by an off-resonant traveling laser beam with both a Gaussian and a TEM 01 profile and with both red and blue detuning of as much as 50 GHz. Phase variations of more than 1000 rad were recovered from velocity-selective measurements of the propagation of the atomic beam and were found to be in quantitative agreement with theoretical predictions based on independently measured phase object intensity profiles and detunings

A Beam Quality Monitor for LHC Beams in the SPS

CERN Document Server

Papotti, G

2008-01-01

The SPS Beam Quality Monitor (BQM) system monitors the longitudinal parameters of the beam before extraction to the LHC to prevent losses and degradation of the LHC luminosity by the injection of low quality beams. It is implemented in two priority levels. At the highest level the SPS-LHC synchronization and global beam structure are verified. If the specifications are not met, the beam should be dumped in the SPS before extraction. On the second level, individual bunch position, length and stability are checked for beam quality assessment. Tolerances are adapted to the mode of operation and extraction to the LHC can also be inhibited. Beam parameters are accessed by acquiring bunch profiles with a longitudinal pick up and fast digital oscilloscope. The beam is monitored for instabilities during the acceleration cycle and thoroughly checked a few ms before extraction for a final decision on extraction interlock. Dedicated hardware and software components implementing fast algorithms are required. In this pape...

Wide spectral band beam analysis

Science.gov (United States)

Aharon, Oren