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.

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

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.

Beam profile effects on NPB [neutral particle beam] performance

International Nuclear Information System (INIS)

LeClaire, R.J. Jr.

1988-03-01

A comparison of neutral particle beam brightness for various neutral beam profiles indicates that the widely used assumption of a Gaussian profile may be misleading for collisional neutralizers. An analysis of available experimental evidence shows that lower peaks and higher tails, compared to a Gaussian beam profile, are observed out of collisional neutralizers, which implies that peak brightness is over estimated, and for a given NPB platform-to-target range, the beam current (power), dwell time or some combination of such engagement parameters would have to be altered to maintain a fixed dose on target. Based on the present analysis, this factor is nominally about 2.4 but may actually be as low as 1.8 or as high as 8. This is an important consideration in estimating NPB constellation performance in SDI engagement contexts. 2 refs., 6 figs

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.

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

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)

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.

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)

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

Precision shape modification of nanodevices with a low-energy electron beam

Science.gov (United States)

Zettl, Alex; Yuzvinsky, Thomas David; Fennimore, Adam

2010-03-09

Methods of shape modifying a nanodevice by contacting it with a low-energy focused electron beam are disclosed here. In one embodiment, a nanodevice may be permanently reformed to a different geometry through an application of a deforming force and a low-energy focused electron beam. With the addition of an assist gas, material may be removed from the nanodevice through application of the low-energy focused electron beam. The independent methods of shape modification and material removal may be used either individually or simultaneously. Precision cuts with accuracies as high as 10 nm may be achieved through the use of precision low-energy Scanning Electron Microscope scan beams. These methods may be used in an automated system to produce nanodevices of very precise dimensions. These methods may be used to produce nanodevices of carbon-based, silicon-based, or other compositions by varying the assist gas.

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.

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 self-calibrating ionisation chamber for the precise intensity calibration of high-energy heavy-ion beam monitors

International Nuclear Information System (INIS)

Junghans, A.

1996-01-01

The intensity of a 136 Xe(600 A MeV) beam has been determined by simultaneously measuring the particle rate and the corresponding ionisation current with an ionisation chamber. The ionisation current of this self-calibrating device was compared at higher intensities with the current of a secondary-electron monitor and a calibration of the secondary-electron current was achieved with a precision of 2%. This method can be applied to all high-energy heavy-ion beams. (orig.)

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

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)

Deterministic ion beam material adding technology for high-precision optical surfaces.

Science.gov (United States)

Liao, Wenlin; Dai, Yifan; Xie, Xuhui; Zhou, Lin

2013-02-20

Although ion beam figuring (IBF) provides a highly deterministic method for the precision figuring of optical components, several problems still need to be addressed, such as the limited correcting capability for mid-to-high spatial frequency surface errors and low machining efficiency for pit defects on surfaces. We propose a figuring method named deterministic ion beam material adding (IBA) technology to solve those problems in IBF. The current deterministic optical figuring mechanism, which is dedicated to removing local protuberances on optical surfaces, is enriched and developed by the IBA technology. Compared with IBF, this method can realize the uniform convergence of surface errors, where the particle transferring effect generated in the IBA process can effectively correct the mid-to-high spatial frequency errors. In addition, IBA can rapidly correct the pit defects on the surface and greatly improve the machining efficiency of the figuring process. The verification experiments are accomplished on our experimental installation to validate the feasibility of the IBA method. First, a fused silica sample with a rectangular pit defect is figured by using IBA. Through two iterations within only 47.5 min, this highly steep pit is effectively corrected, and the surface error is improved from the original 24.69 nm root mean square (RMS) to the final 3.68 nm RMS. Then another experiment is carried out to demonstrate the correcting capability of IBA for mid-to-high spatial frequency surface errors, and the final results indicate that the surface accuracy and surface quality can be simultaneously improved.

High precision, rapid laser hole drilling

Science.gov (United States)

Chang, Jim J.; Friedman, Herbert W.; Comaskey, Brian J.

2013-04-02

A laser system produces a first laser beam for rapidly removing the bulk of material in an area to form a ragged hole. The laser system produces a second laser beam for accurately cleaning up the ragged hole so that the final hole has dimensions of high precision.

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)

Impact of beam-beam effects on precision luminosity measurements at the ILC

Energy Technology Data Exchange (ETDEWEB)

Rimbault, C [LAL, Univ Paris-Sud, IN2P3/CNRS, Orsay (France); Bambade, P [LAL, Univ Paris-Sud, IN2P3/CNRS, Orsay (France); Moenig, K [DESY, Zeuthen (Germany); Schulte, D [CERN, Geneva (Switzerland)

2007-09-15

In this paper, the impact of beam-beam effects on the precision luminosity measurement at the International Linear Collider is investigated quantitatively for the first time. GUINEA-PIG, a beam-beam interaction simulation tool, is adapted to treat the space charge effects affecting the Bhabha events used in this measurement. The biases due to the resulting changes in kinematics are evaluated for different center-of-mass energies and beam parameters.

Impact of beam-beam effects on precision luminosity measurements at the ILC

CERN Document Server

Rimbault, C; Mönig, K; Schulte, D

2007-01-01

In this paper, the impact of beam-beam effects on the precision luminosity measurement at the International Linear Collider is investigated quantitatively for the first time. GUINEA-PIG, a beam-beam interaction simulation tool, is adapted to treat the space charge effects affecting the Bhabha events used in this measurement. The biases due to the resulting changes in kinematics are evaluated for different center-of-mass energies and beam parameters.

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...

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)

A modified time-of-flight method for precise determination of high speed ratios in molecular beams

Energy Technology Data Exchange (ETDEWEB)

Salvador Palau, A.; Eder, S. D., E-mail: sabrina.eder@uib.no; Kaltenbacher, T.; Samelin, B.; Holst, B. [Department of Physics and Technology, University of Bergen, Allégaten 55, 5007 Bergen (Norway); Bracco, G. [Department of Physics and Technology, University of Bergen, Allégaten 55, 5007 Bergen (Norway); CNR-IMEM, Department of Physics, University of Genova, V. Dodecaneso 33, 16146 Genova (Italy)

2016-02-15

Time-of-flight (TOF) is a standard experimental technique for determining, among others, the speed ratio S (velocity spread) of a molecular beam. The speed ratio is a measure for the monochromaticity of the beam and an accurate determination of S is crucial for various applications, for example, for characterising chromatic aberrations in focussing experiments related to helium microscopy or for precise measurements of surface phonons and surface structures in molecular beam scattering experiments. For both of these applications, it is desirable to have as high a speed ratio as possible. Molecular beam TOF measurements are typically performed by chopping the beam using a rotating chopper with one or more slit openings. The TOF spectra are evaluated using a standard deconvolution method. However, for higher speed ratios, this method is very sensitive to errors related to the determination of the slit width and the beam diameter. The exact sensitivity depends on the beam diameter, the number of slits, the chopper radius, and the chopper rotation frequency. We present a modified method suitable for the evaluation of TOF measurements of high speed ratio beams. The modified method is based on a systematic variation of the chopper convolution parameters so that a set of independent measurements that can be fitted with an appropriate function are obtained. We show that with this modified method, it is possible to reduce the error by typically one order of magnitude compared to the standard method.

Pulsed beams as field probes for precision measurement

International Nuclear Information System (INIS)

Hudson, J. J.; Ashworth, H. T.; Kara, D. M.; Tarbutt, M. R.; Sauer, B. E.; Hinds, E. A.

2007-01-01

We describe a technique for mapping the spatial variation of static electric, static magnetic, and rf magnetic fields using a pulsed atomic or molecular beam. The method is demonstrated using a beam designed to measure the electric dipole moment of the electron. We present maps of the interaction region, showing sensitivity to (i) electric field variation of 1.5 V/cm at 3.3 kV/cm with a spatial resolution of 15 mm; (ii) magnetic field variation of 5 nT with 25 mm resolution; (iii) radio-frequency magnetic field amplitude with 15 mm resolution. This diagnostic technique is very powerful in the context of high-precision atomic and molecular physics experiments, where pulsed beams have not hitherto found widespread application

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.)

Beam profile measurements on RHIC

International Nuclear Information System (INIS)

Connolly, R.; Michnoff, R.; Moore, T.; Shea, T.; Tepikian, S.

2000-01-01

The Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Lab was commissioned during the summer of 1999. Transverse beam profiles on RHIC are measured with ionization profile monitors (IPMs). An IPM measures beam profiles by collecting the electrons liberated by residual gas ionization by the beam. The detector is placed in the gap of a dipole magnet to force the electrons to travel in straight lines from the beamline center to the collector. One IPM was tested and it measured the profiles of a single gold bunch containing 10 8 ions on consecutive turns. We show an example of one of these profiles giving transverse emittance. Also several profiles are combined into a mountain-range plot which shows betatron oscillations at injection

Simple beam profile monitor

Energy Technology Data Exchange (ETDEWEB)

Gelbart, W.; Johnson, R. R.; Abeysekera, B. [ASD Inc. Garden Bay, BC (Canada); Best Theratronics Ltd Ottawa Ontario (Canada); PharmaSpect Ltd., Burnaby BC (Canada)

2012-12-19

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

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

Beam profile monitors for a tagged photon beam facility

International Nuclear Information System (INIS)

Arends, J.; Breuer, M.; Dahmen, H.D.; Detemple, P.; Schneider, W.; Urban, D.; Zucht, B.

1991-01-01

A beam profile monitor for electron and photon beams is described, which operates at the low intensities encountered in a tagged bremsstrahlung beam environment, typically 10 10 electrons/s and 10 7 photons/s. The method is based on a wire scanner and utilizes the presence of a tagging spectrometer. The accuracy of the measurements can be tuned in a wide range to meet the requirements set by the actual beam parameters. Examples of measured electron and photon beam profiles at the tagged photon beam of the PHOENICS experiment at the electron stretcher ring ELSA in Bonn are given. (orig.)

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.

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.

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.

Beta Beams for Precision Measurements of Neutrino Oscillation Parameters

CERN Document Server

Wildner, E; Hansen, C; De Melo Mendonca, T; Stora, T; Damjanovic, S; Payet, J; Chancé, A; Zorin, V; Izotov, I; Rasin, S; Sidorov, A; Skalyga, V; De Angelis, G; Prete, G; Cinausero, M; Kravchuk, V; Gramegna, F; Marchi, T; Collazuol, G; Mezzetto, M; Delbar, T; Loiselet, M; Keutgen, T; Mitrofanov, S; Burt, G; Dexter, A; Lamy, T; Latrasse, L; Marie-Jeanne, M; Sortais, P; Thuillier, T; Debray, F; Trophime, C; Hass, M; Hirsh, T; Berkovits, D; Stahl, A; Vardaci, E; Di Nitto, A; Brondi, A; La Rana, G; Moro, R; De Rosa, G; Palladino, V

2012-01-01

Neutrino oscillations have implications for the Standard Model of particle physics. The CERN Beta Beam has outstanding capabilities to contribute to precision measurements of the parameters governing neutrino oscillations. The FP7 collaboration EUROnu (2008-2012) is a design study that will review three facilities (Super-Beams, Beta Beams and Neutrino Factories) and perform a cost assessment that, coupled with the physics performance, will give means to the European research authorities to make decisions on future European neutrino oscillation facilities. ”Beta Beams” produce collimated pure electron (anti)neutrinos by accelerating beta active ions to high energies and having them decay in a storage ring. Using existing machines and infrastructure is an advantage for the cost evaluation; however, this choice is also constraining the Beta Beams. Recent work to make the Beta Beam facility a solid option will be described: production of Beta Beam isotopes, the 60 GHz pulsed ECR source development, integratio...

A beam profile monitor for a tagged photon beam

International Nuclear Information System (INIS)

Arends, J.; Breuer, M.; Dahmen, H.D.; Detemple, P.; Noeldeke, G.; Schneider, W.; Zucht, B.

1990-10-01

A beam profile monitor for electron and photon beams is described, which operates at the low intensities encountered in a tagged bremsstrahlung beam environment, typically 10 10 electrons/s and 10 7 photons/s. The method is based on a wire scanner and utilizes the presence of a tagging spectrometer. The accuracy of the measurements can be tuned in a wide range (at the expense of measuring time) to meet the requirements set by the actual beam size. Examples of measured electron and photon beam profiles at the tagged photon beam of the PHOENICS experiment at the electron stretcher ring ELSA are given. (orig.)

A beam profile monitor for a tagged photon beam

Energy Technology Data Exchange (ETDEWEB)

Arends, J.; Breuer, M.; Dahmen, H.D.; Detemple, P.; Noeldeke, G.; Schneider, W.; Zucht, B.

1990-10-01

A beam profile monitor for electron and photon beams is described, which operates at the low intensities encountered in a tagged bremsstrahlung beam environment, typically 10{sup 10} electrons/s and 10{sup 7} photons/s. The method is based on a wire scanner and utilizes the presence of a tagging spectrometer. The accuracy of the measurements can be tuned in a wide range (at the expense of measuring time) to meet the requirements set by the actual beam size. Examples of measured electron and photon beam profiles at the tagged photon beam of the PHOENICS experiment at the electron stretcher ring ELSA are given. (orig.).

Profile measurement of a bent neutron mirror using an ultrahigh precision non-contact measurement system with an auto focus laser probe

International Nuclear Information System (INIS)

Morita, S; Guo, J; Yamagata, Y; Yamada, N L; Torikai, N; Takeda, S; Furusaka, M

2016-01-01

A bent neutron mirror has been considered as one of the best solutions for focusing neutron beams from the viewpoint of cost-benefit performance. Although the form deviation of the bent profile is expected because of the large spot size, it is difficult to measure due to its geometric limitation. Here, we propose a non-contact measurement system using an auto focus (AF) laser probe on an ultrahigh precision machine tool to precisely evaluate the form deviation of the bent mirror. The AF laser probe is composed of a diode laser, a position sensitive sensor, a charge-coupled device (CCD) camera and a microscope objective lens which is actuated by an electromagnetic motor with 1 nm resolution for position sensing and control. The sensor enables a non-contact profile measurement of a high precision surface without any surface damage in contrast with contact-type ultrahigh precision coordinate measurement machines with ruby styli. In the on-machine measurement system, a personal computer simultaneously acquires a displacement signal from the AF laser probe and 3-axis positional coordinates of the ultrahigh machine tool branched between the linear laser scales and the numerical controller. The acquisition rate of the 4-axis positional data in 1 nm resolution is more than 10 Hz and the simultaneity between the axes is negligible. The profile of a neutron bent mirror was measured from a transparent side using the developed system, and the result proves that the form deviation of the mirror enlarged the the spot size of focused neuron beam. (paper)

Qualification of a Monte Carlo model of photon beams of a Lilac Elekta Precise

International Nuclear Information System (INIS)

Linares R, H. M.; Laguardia, R. A.; Lara M, E.

2014-08-01

For the simulation of the accelerator head the parameters determination that characterize the electrons primary beam that affect in the target is a step that involves a fundamental role in the precision of the Monte Carlo calculations. Applying the proposed methodology by Pena et al. [2007], in this work was carried out the qualification of the photon beams (6 MV and 15 MV) of an accelerator Elekta Precise, using the Monte Carlo code EGSnrc. The influence exerted by the characteristics of the electrons primary beam on the distribution of absorbed dose for the two energy of this equipment was studied. Using different mid energy combinations and FWHM of the electrons primary beam was calculated the dose deposited in a segmented water mannequin with its surface to 100 cm of the source. Starting from the deposited dose in the mannequin the dose curves in depth and dose profiles to different depths were built. These curves were compared with measured values in a similar experimental arrangement to the carried out simulation, applying acceptability criteria based on confidence intervals [Venselaar et al. 2001]. The dose profiles for small fields were like it was expected, to be strongly influenced by the radial distribution (FWHM). The energy/FWHM combinations that better reproduce the experimental curves of each photon beam were determined. One time determined the best combination (5.75 MeV/2 mm and 11.25 MeV/2 mm, respectively) was used for the generation of the phase spaces and the field factors calculation. A good correspondence was obtained between the simulations and the measurements for a wide range of field sizes, as well as for different types of detectors, being all the results inside of the tolerance margins. (author)

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

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

Wire Scanner Beam Profile Measurements: LANSCE Facility Beam Development

International Nuclear Information System (INIS)

Gilpatrick, John D.; Batygin, Yuri K.; Gonzales, Fermin; Gruchalla, Michael E.; Kutac, Vincent G.; Martinez, Derwin; Sedillo, James Daniel; Pillai, Chandra; Rodriguez Esparza, Sergio; Smith, Brian G.

2012-01-01

The Los Alamos Neutron Science Center (LANSCE) is replacing Wire Scanner (WS) beam profile measurement systems. Three beam development tests have taken place to test the new wire scanners under beam conditions. These beam development tests have integrated the WS actuator, cable plant, electronics processors and associated software and have used H - beams of different beam energy and current conditions. In addition, the WS measurement-system beam tests verified actuator control systems for minimum profile bin repeatability and speed, checked for actuator backlash and positional stability, tested the replacement of simple broadband potentiometers with narrow band resolvers, and tested resolver use with National Instruments Compact Reconfigurable Input and Output (cRIO) Virtual Instrumentation. These beam tests also have verified how trans-impedance amplifiers react with various types of beam line background noise and how noise currents were not generated. This paper will describe these beam development tests and show some resulting data.

Wire Scanner Beam Profile Measurements: LANSCE Facility Beam Development

Energy Technology Data Exchange (ETDEWEB)

Gilpatrick, John D. [Los Alamos National Laboratory; Batygin, Yuri K. [Los Alamos National Laboratory; Gonzales, Fermin [Los Alamos National Laboratory; Gruchalla, Michael E. [Los Alamos National Laboratory; Kutac, Vincent G. [Los Alamos National Laboratory; Martinez, Derwin [Los Alamos National Laboratory; Sedillo, James Daniel [Los Alamos National Laboratory; Pillai, Chandra [Los Alamos National Laboratory; Rodriguez Esparza, Sergio [Los Alamos National Laboratory; Smith, Brian G. [Los Alamos National Laboratory

2012-05-15

The Los Alamos Neutron Science Center (LANSCE) is replacing Wire Scanner (WS) beam profile measurement systems. Three beam development tests have taken place to test the new wire scanners under beam conditions. These beam development tests have integrated the WS actuator, cable plant, electronics processors and associated software and have used H{sup -} beams of different beam energy and current conditions. In addition, the WS measurement-system beam tests verified actuator control systems for minimum profile bin repeatability and speed, checked for actuator backlash and positional stability, tested the replacement of simple broadband potentiometers with narrow band resolvers, and tested resolver use with National Instruments Compact Reconfigurable Input and Output (cRIO) Virtual Instrumentation. These beam tests also have verified how trans-impedance amplifiers react with various types of beam line background noise and how noise currents were not generated. This paper will describe these beam development tests and show some resulting data.

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

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)

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.

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)

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

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

Science.gov (United States)

Nedzelskiy, I S; Korotkov, A; Brix, M; Morgan, P; Vince, J

2010-10-01

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

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-scanning system for determination of beam profiles and form factors in merged-beam experiments

International Nuclear Information System (INIS)

Keyser, C.J.; Froelich, H.R.; Mitchell, J.B.A.; McGowan, J.W.

1979-01-01

A beam-scanning system for a merged electron-ion beam experiment is described. This system is used to determine the horizontal and vertical beam profiles and the form factors at three different locations along the axis of the beams. Design details of the wedge-shaped scanners and the electronic circuit for obtaining beam profiles and form factors are described. The form factor derivation for merged beams is given and an expression in terms of measured quantities is derived. (author)

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.

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 ...

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.

Development of a Method to Assess the Precision Of the z-axis X-ray Beam Collimation in a CT Scanner

Science.gov (United States)

Kim, Yon-Min

2018-05-01

Generally X-ray equipment specifies the beam collimator for the accuracy measurement as a quality control item, but the computed tomography (CT) scanner with high dose has no collimator accuracy measurement item. If the radiation dose is to be reduced, an important step is to check if the beam precisely collimates at the body part for CT scan. However, few ways are available to assess how precisely the X-ray beam is collimated. In this regard, this paper provides a way to assess the precision of z-axis X-ray beam collimation in a CT scanner. After the image plate cassette had been exposed to the X-ray beam, the exposed width was automatically detected by using a computer program developed by the research team to calculate the difference between the exposed width and the imaged width (at isocenter). The result for the precision of z-axis X-ray beam collimation showed that the exposed width was 3.8 mm and the overexposure was high at 304% when a narrow beam of a 1.25 mm imaged width was used. In this study, the precision of the beam collimation of the CT scanner, which is frequently used for medical services, was measured in a convenient way by using the image plate (IP) cassette.

Precision Lifetime Measurements Using LaBr3 Detectors With Stable and Radioactive Beams

Directory of Open Access Journals (Sweden)

Regan P.H.

2013-12-01

Full Text Available A range of high resolution gamma-ray spectroscopy measurements have been carried out using arrays which include a number of Cerium-doped Lanthanum-Tribromide (LrBr3(Ce scintillation detectors used in conjunction with high-resolution hyper-pure germanium detectors. Examples of the spectral and temporal responses of such set-ups, using both standard point radioactive sources 152Eu and 56Co, and in-beam fusionevaporation reaction experiments for precision measurements of nuclear excited states in 34P and 138Ce are presented. The current and future use of such arrays at existing (EURICA at RIKEN and future (NUSTAR at FAIR secondary radioactive beam facilities for precision measurements of excited nuclear state lifetimes in the 10 ps to 10 ns regime are also discussed.

Recent high precision surveys at PEP

International Nuclear Information System (INIS)

Sah, R.C.

1980-12-01

The task of surveying and aligning the components of PEP has provided an opportunity to develop new instruments and techniques for the purpose of high precision surveys. The new instruments are quick and easy to use, and they automatically encode survey data and read them into the memory of an on-line computer. When measurements of several beam elements have been taken, the on-line computer analyzes the measured data, compares them with desired parameters, and calculates the required adjustments to beam element support stands

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

High-precision hyperfine structure measurement in slow atomic ion beams by collinear laser-rf double resonance

International Nuclear Information System (INIS)

Amarjit Sen; Childs, W.J.; Goodman, L.S.

1987-01-01

A new collinear laser-ion beam apparatus for slow ions (1 to 1.5 keV) has been built for measuring the hyperfine structure of metastable levels of ions with laser-rf double resonance technique. Narrow linewidths of ∼60 kHz (FWHM) have been observed for the first time in such systems. As a first application the hyperfine structure of the 4f 7 ( 8 S 0 )5d 9 D/sub J/ 0 metastable levels of /sup 151,153/Eu + has been measured with high precision. 10 refs., 8 figs

Acquisition and display of beam profilers

International Nuclear Information System (INIS)

David, L.; Duneau, P.; Lecorche, E.; Lermine, P.; Vila, J.; Maugeais, C.; Ulrich, M.

1995-01-01

The ion beam adjustment requires the knowledge of its shape (its profile). A new electronic interface has been developed for the older multiwire profiles, while an other electronic equipment has been developed for the gas profiles and the microchannel plates. The data from these interfaces are computed to get numerical values and profile shapes, then transmitted by the network to the main control room to be displayed (shapes and data) on every workstation, by different beam tuning programs. (author)

From neutrino physics to beam polarisation. A high precision story at the ILC

International Nuclear Information System (INIS)

Vormwald, Benedikt

2014-03-01

In this thesis, we investigate the experimental prospects of studying a supersymmetric model with bilinearly broken R parity at the International Linear Collider. In this model, neutrinos mix with the supersymmetric neutralinos such that neutrino properties can be probed by examining neutralino decays, which incorporate usually a lepton and a W/Z boson. As a study case, we focus on the determination of the atmospheric neutrino mixing angle θ 23 , which is accessible via the ratio of the neutralino branching ratios BR(χ 0 1 →Wμ)/BR(χ 0 1 →Wτ). A detailed simulation of the International Large Detector has been performed for all Standard Model backgrounds and for χ 0 1 -pair production within a simplified model. The study is based on ILC beam parameters according to the Technical Design Report for a center-of-mass energy of √(s)=500 GeV. From muonic χ 0 1 decays, we find that the χ 0 1 mass can be reconstructed with an uncertainty of δ(m χ 0 1 )=(40(stat.)+35(syst.)) MeV for an integrated luminosity of ∫Ldt=500 fb -1 . The ratio of branching ratios can be determined to a precision of δ(BR(χ 0 1 →Wμ)/BR(χ 0 1 →Wτ))=2.9%. Due to this, the atmospheric neutrino mixing angle can be deduced with a precision comparable to modern neutrino experiments. Thus, the ILC is capable to test whether bRPV SUSY is the mechanism of neutrino mass generation. As also shown in the bRPV SUSY study of this thesis, beam polarisation is an important parameter in physics analyses at the ILC. The beam polarisation is measured with two Compton polarimeters per electron/positron beam. In order to achieve the design goal of an envisaged precision of 0.25%, the detector nonlinearity of the used Cherenkov detectors has to be determined very precisely. Herein, the main source of nonlinearity is expected to originate from the involved photomultipliers. For this reason, a differential nonlinearity measurement as well as a linearisation method is developed. The working

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...

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.

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.

Properties of the proton therapy. A high precision radiotherapy

International Nuclear Information System (INIS)

Anon.

2005-01-01

The proton therapy is a radiotherapy using protons beams. The protons present interesting characteristics but they need heavy technologies to be used, such particles accelerators, radiation protection wall and sophisticated technologies to reach the high precision allowed by their ballistic qualities (planning of treatment, beam conformation and patient positioning). (N.C.)

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

High precision timing in a FLASH

Energy Technology Data Exchange (ETDEWEB)

Hoek, Matthias; Cardinali, Matteo; Dickescheid, Michael; Schlimme, Soeren; Sfienti, Concettina; Spruck, Bjoern; Thiel, Michaela [Institut fuer Kernphysik, Johannes Gutenberg-Universitaet Mainz (Germany)

2016-07-01

A segmented highly precise start counter (FLASH) was designed and constructed at the Institute for Nuclear Physics in Mainz. Besides determining a precise reference time, a Time-of-Flight measurement can be performed with two identical FLASH units. Thus, particle identification can be provided for mixed hadron beam environments. The detector design is based on the detection of Cherenkov light produced in fused silica radiator bars with fast multi-anode MCP-PMTs. The segmentation of the radiator improves the timing resolution while allowing a coarse position resolution along one direction. Both, the arrival time and the Time-over-Threshold are determined by the readout electronics, which enables walk correction of the arrival time. The performance of two FLASH units was investigated in test experiments at the Mainz Microton (MAMI) using an electron beam with an energy of 855 MeV and at CERN's PS T9 beam line with a mixed hadron beam with momenta between 3-8 GeV/c. Effective Time-walk correction methods based on Time-over-Threshold were developed for the data analysis. The achieved Time-Of-Flight resolution after applying all corrections was found to be 70 ps. Furthermore, the PID and position resolution capabilities are discussed in this contribution.

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

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.

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.

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

From neutrino physics to beam polarisation. A high precision story at the ILC

Energy Technology Data Exchange (ETDEWEB)

Vormwald, Benedikt

2014-03-15

In this thesis, we investigate the experimental prospects of studying a supersymmetric model with bilinearly broken R parity at the International Linear Collider. In this model, neutrinos mix with the supersymmetric neutralinos such that neutrino properties can be probed by examining neutralino decays, which incorporate usually a lepton and a W/Z boson. As a study case, we focus on the determination of the atmospheric neutrino mixing angle θ{sub 23}, which is accessible via the ratio of the neutralino branching ratios BR(χ{sup 0}{sub 1}→Wμ)/BR(χ{sup 0}{sub 1}→Wτ). A detailed simulation of the International Large Detector has been performed for all Standard Model backgrounds and for χ{sup 0}{sub 1}-pair production within a simplified model. The study is based on ILC beam parameters according to the Technical Design Report for a center-of-mass energy of √(s)=500 GeV. From muonic χ{sup 0}{sub 1} decays, we find that the χ{sup 0}{sub 1} mass can be reconstructed with an uncertainty of δ(m{sub χ{sup 0}{sub 1}})=(40(stat.)+35(syst.)) MeV for an integrated luminosity of ∫Ldt=500 fb{sup -1}. The ratio of branching ratios can be determined to a precision of δ(BR(χ{sup 0}{sub 1}→Wμ)/BR(χ{sup 0}{sub 1}→Wτ))=2.9%. Due to this, the atmospheric neutrino mixing angle can be deduced with a precision comparable to modern neutrino experiments. Thus, the ILC is capable to test whether bRPV SUSY is the mechanism of neutrino mass generation. As also shown in the bRPV SUSY study of this thesis, beam polarisation is an important parameter in physics analyses at the ILC. The beam polarisation is measured with two Compton polarimeters per electron/positron beam. In order to achieve the design goal of an envisaged precision of 0.25%, the detector nonlinearity of the used Cherenkov detectors has to be determined very precisely. Herein, the main source of nonlinearity is expected to originate from the involved photomultipliers. For this reason, a differential

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

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

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

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

Inland and Near Shore Water Profiles Derived from the High Altitude Multiple Altimeter Beam Experimental Lidar (MABEL)

Science.gov (United States)

Jasinski, Michael F.; Stoll, Jeremy D.; Cook, William B.; Ondrusek, Michael; Stengel, Eric; Brunt, Kelly

2016-01-01

The Advanced Topographic Laser Altimeter System (ATLAS) on the Ice, Cloud, and Land Elevation Satellite (ICESat-2) mission is a six beam, low energy, high repetition rate, 532 nm laser transmitter with photon counting detectors. Although designed primarily for detecting height changes in icecaps, sea ice and vegetation, the polar-orbital satellite will observe global surface water during its designed three year life span, including inland water bodies, coasts, and open oceans. In preparation for the mission, an ICESat-2 prototype or the Multiple Altimeter Beam Experimental Lidar (MABEL), was built and flown on high altitude aircraft experiments over a range of inland and near-shore targets. The purpose was to test the ATLAS concept and to provide a database for developing an algorithm that detects along track surface water height and light penetration under a range of atmospheric and water conditions. The current analysis examines the datasets of three MABEL transects observed from 20 km above ground of coastal and inland waters conducted in 2012 and 2013. Transects ranged from about 2 to 12 km in length and included the middle Chesapeake Bay, the near shore Atlantic coast at Virginia Beach, and Lake Mead. Results indicate MABEL's high capability for retrieving surface water height statistics with a mean height precision of approximately 5-7 cm per 100m segment length. Profiles of attenuated subsurface backscatter, characterized using a Signal to Background Ratio written in Log10 base, or LSBR0, were observed over a range of 1.3 to 9.3 meters depending on water clarity and atmospheric background. Results indicate that observable penetration depth, although primarily dependent on water properties, was greatest when solar background rate was low. Near shore bottom reflectance was detected only at the Lake Mead site down to maximum of 10 m under a clear night sky and low turbidity of approximately 1.6 Nephelometric Turbidity Units (NTU). The overall results suggest

Fast, High-Precision Optical Polarization Synthesizer for Ultracold-Atom Experiments

Science.gov (United States)

Robens, Carsten; Brakhane, Stefan; Alt, Wolfgang; Meschede, Dieter; Zopes, Jonathan; Alberti, Andrea

2018-03-01

We present a technique for the precision synthesis of arbitrary polarization states of light with a high modulation bandwidth. Our approach consists of superimposing two laser light fields with the same wavelength, but with opposite circular polarizations, where the phase and the amplitude of each light field are individually controlled. We find that the polarization-synthesized beam reaches a degree of polarization of 99.99%, which is mainly limited by static spatial variations of the polarization state over the beam profile. We also find that the depolarization caused by temporal fluctuations of the polarization state is about 2 orders of magnitude smaller. In a recent work, Robens et al. [Low-Entropy States of Neutral Atoms in Polarization-Synthesized Optical Lattices, Phys. Rev. Lett. 118, 065302 (2017), 10.1103/PhysRevLett.118.065302] demonstrated an application of the polarization synthesizer to create two independently controllable optical lattices which trap atoms depending on their internal spin state. We use ultracold atoms in polarization-synthesized optical lattices to give an independent, in situ demonstration of the performance of the polarization synthesizer.

High precision patterning of ITO using femtosecond laser annealing process

International Nuclear Information System (INIS)

Cheng, Chung-Wei; Lin, Cen-Ying

2014-01-01

Highlights: • We have reported a process of fabrication of crystalline indium tin oxide (c-ITO) patterns using femtosecond laser-induced crystallization with a Gaussian beam profile followed by chemical etching. • The experimental results have demonstrated that the ablation and crystallization threshold fluences of a-ITO thin film are well-defined, the line width of the c-ITO patterns is controllable. • Fast fabrication of the two parallel sub-micro (∼0.5 μm) c-ITO line patterns using a single femtosecond laser beam and a single scanning path can be achieved. • A long-length sub-micro c-ITO line pattern is fabricated, and the feasibility of fabricating c-ITO patterns is confirmed, which are expected to be used in micro-electronics devices. - Abstract: High precision patterning of crystalline indium tin oxide (c-ITO) patterns on amorphous ITO (a-ITO) thin films by femtosecond laser-induced crystallization with a Gaussian beam profile followed by chemical etching is demonstrated. In the proposed approach, the a-ITO thin film is selectively transformed into a c-ITO structure via a low heat affect zone and the well-defined thresholds (ablation and crystallization) supplied by the femtosecond laser pulse. The experimental results show that by careful control of the laser fluence above the crystallization threshold, c-ITO patterns with controllable line widths and ridge-free characteristics can be accomplished. By careful control of the laser fluence above the ablation threshold, fast fabrication of the two parallel sub-micro c-ITO line patterns using a single femtosecond laser beam and single scanning path can be achieved. Along-length sub-micro c-ITO line pattern is fabricated, and the feasibility of fabricating c-ITO patterns is confirmed, which are expected to be used in micro-electronics devices

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.

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

International Nuclear Information System (INIS)

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

1995-05-01

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

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

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

International Nuclear Information System (INIS)

Bick, D.

2007-04-01

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

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

Energy Technology Data Exchange (ETDEWEB)

Bick, D.

2007-04-15

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

Fast and Precise Beam Energy Measurement using Compton Backscattering at e+e- Colliders

CERN Document Server

Kaminskiy, V V; Muchnoi, N Yu; Zhilich, V N

2017-01-01

The report describes a method for a fast and precise beam energy measurement in the beam energy range 0.5-2 GeV and its application at various e+e- colliders. Low-energy laser photons interact head-on with the electron or positron beam and produce Compton backscattered photons whose energy is precisely measured by HPGe detector. The method allows measuring the beam energy with relative accuracy of ∼2-5.10-5. The method was successfully applied at VEPP-4M, VEPP-3, VEPP-2000 (BINP, Russia) and BEPC-II (IHEP, China).

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

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

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

Qualification of a Monte Carlo model of photon beams of a Lilac Elekta Precise; Habilitacion de un modelo Monte Carlo de haces de fotones de un linac Elekta Precise

Energy Technology Data Exchange (ETDEWEB)

Linares R, H. M.; Laguardia, R. A. [Instituto Superior de Tecnologias y Ciencias Aplicadas, Av. Salvador Allende Esq. Luaces, Quinta de los Molinos, Plaza de la Revolucion, 10600 La Habana (Cuba); Lara M, E., E-mail: elier@inor.sld.cu [Instituto Nacional de Oncologia y Radioterapia, Av. 29 y E. Vedado, 10400 La Habana (Cuba)

2014-08-15

For the simulation of the accelerator head the parameters determination that characterize the electrons primary beam that affect in the target is a step that involves a fundamental role in the precision of the Monte Carlo calculations. Applying the proposed methodology by Pena et al. [2007], in this work was carried out the qualification of the photon beams (6 MV and 15 MV) of an accelerator Elekta Precise, using the Monte Carlo code EGSnrc. The influence exerted by the characteristics of the electrons primary beam on the distribution of absorbed dose for the two energy of this equipment was studied. Using different mid energy combinations and FWHM of the electrons primary beam was calculated the dose deposited in a segmented water mannequin with its surface to 100 cm of the source. Starting from the deposited dose in the mannequin the dose curves in depth and dose profiles to different depths were built. These curves were compared with measured values in a similar experimental arrangement to the carried out simulation, applying acceptability criteria based on confidence intervals [Venselaar et al. 2001]. The dose profiles for small fields were like it was expected, to be strongly influenced by the radial distribution (FWHM). The energy/FWHM combinations that better reproduce the experimental curves of each photon beam were determined. One time determined the best combination (5.75 MeV/2 mm and 11.25 MeV/2 mm, respectively) was used for the generation of the phase spaces and the field factors calculation. A good correspondence was obtained between the simulations and the measurements for a wide range of field sizes, as well as for different types of detectors, being all the results inside of the tolerance margins. (author)

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.)

System and method for high precision isotope ratio destructive analysis

Science.gov (United States)

Bushaw, Bruce A; Anheier, Norman C; Phillips, Jon R

2013-07-02

A system and process are disclosed that provide high accuracy and high precision destructive analysis measurements for isotope ratio determination of relative isotope abundance distributions in liquids, solids, and particulate samples. The invention utilizes a collinear probe beam to interrogate a laser ablated plume. This invention provides enhanced single-shot detection sensitivity approaching the femtogram range, and isotope ratios that can be determined at approximately 1% or better precision and accuracy (relative standard deviation).

Effects of X-ray tube parameters on thickness measure precision in X-ray profile gauge

International Nuclear Information System (INIS)

Miao Jichen; Wu Zhifang; Xing Guilai

2011-01-01

Instantaneous profile gauge technology has been widely used in metallurgy industry because it can on-line get the profile of steel strip. It has characters of high measure precision and wide measure range, but the X-ray tube parameters only can be set few different values during measurement. The relations of thickness measure precision and X-ray tube current, X-ray tube voltage were analyzed. The results show that the X-ray tube current affects the thickness measure precision and the X-ray tube voltage determines the thickness measure range. The method of estimating the X-ray current by thickness measure precision was provided in the end. This method is the base of X-ray source selection and X-ray source parameter's setting in the instantaneous profile gauge. (authors)

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)

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

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

International Nuclear Information System (INIS)

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

1995-01-01

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

Profiling hydrogen in materials using ion beams

International Nuclear Information System (INIS)

Ziegler, J.F.; Wu, C.P.; Williams, P.

1977-01-01

Over the last few years many ion beam techniques have been reported for the profiling of hydrogen in materials. Nine of these were evaluated using similar samples of hydrogen ion-implanted into silicon. When possible the samples were analyzed using two or more techniques to confirm the ion-implanted accuracy. The results of this analysis which has produced a consensus profile of H in silicon which is useful as a calibration standard are reported. The analytical techniques used have capabilities ranging from very high depth resolution (approximately 50 A) and high sensitivity (less than 1 ppM) to deep probes for hydrogen which can sample throughout thin sheets

Computerized precision control of a synchronous high voltage discharge switch for the beam separation system of the LEP e+/e- collider

International Nuclear Information System (INIS)

Dieperink, J.H.; Finnigan, A.; Kalbreier, W.; Keizer, R.L.; Laffin, M.; Mertens, V.

1989-01-01

Electrostatic separators are used to separate the beams in LEP. The counter-rotating beams are eventually brought into collision in the four low beta insertions, using switches to discharge simultaneously four high voltage (HV) circuits. Each switch consists of four spark gaps mounted in a pressure vessel. A reduction of the gap widths below the self ignition instance by electric motors results in the initiation of the discharges. Synchronization is ensured by the electrical coupling of the electrodes connected to the ground. The design and performance of the computerized precision control of the discharge switch are described. The dynamic characteristics of the prototype switch are also presented. 5 refs., 5 figs

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

High spatial precision nano-imaging of polarization-sensitive plasmonic particles

Science.gov (United States)

Liu, Yunbo; Wang, Yipei; Lee, Somin Eunice

2018-02-01

Precise polarimetric imaging of polarization-sensitive nanoparticles is essential for resolving their accurate spatial positions beyond the diffraction limit. However, conventional technologies currently suffer from beam deviation errors which cannot be corrected beyond the diffraction limit. To overcome this issue, we experimentally demonstrate a spatially stable nano-imaging system for polarization-sensitive nanoparticles. In this study, we show that by integrating a voltage-tunable imaging variable polarizer with optical microscopy, we are able to suppress beam deviation errors. We expect that this nano-imaging system should allow for acquisition of accurate positional and polarization information from individual nanoparticles in applications where real-time, high precision spatial information is required.

Precision profiles and analytic reliability of radioimmunologic methods

International Nuclear Information System (INIS)

Yaneva, Z.; Popova, Yu.

1991-01-01

The aim of the present study is to investigate and compare some methods for creation of 'precision profiles' (PP) and to clarify their possibilities for determining the analytical reliability of RIA. Only methods without complicated mathematical calculations has been used. The reproducibility in serums with a concentration of the determinable hormone in the whole range of the calibration curve has been studied. The radioimmunoassay has been performed with TSH-RIA set (ex East Germany), and comparative evaluations - with commercial sets of HOECHST (Germany) and AMERSHAM (GB). Three methods for obtaining the relationship concentration (IU/l) -reproducibility (C.V.,%) are used and a comparison is made of their corresponding profiles: preliminary rough profile, Rodbard-PP and Ekins-PP. It is concluded that the creation of a precision profile is obligatory and the method of its construction does not influence the relationship's course. PP allows to determine concentration range giving stable results which improves the efficiency of the analitical work. 16 refs., 4 figs

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.

New precise measurement of muonium hyperfine structure interval at J-PARC

Energy Technology Data Exchange (ETDEWEB)

Ueno, Y., E-mail: yueno@radphys4.c.u-tokyo.ac.jp [University of Tokyo, Graduate School of Arts and Sciences (Japan); Aoki, M. [Osaka University, Graduate School of Science (Japan); Fukao, Y. [KEK (Japan); Higashi, Y.; Higuchi, T. [University of Tokyo, Graduate School of Arts and Sciences (Japan); Iinuma, H.; Ikedo, Y. [KEK (Japan); Ishida, K. [RIKEN (Japan); Ito, T. U. [Japan Atomic Energy Agency (Japan); Iwasaki, M. [RIKEN (Japan); Kadono, R. [KEK (Japan); Kamigaito, O. [RIKEN (Japan); Kanda, S. [University of Tokyo, Department of Physics (Japan); Kawall, D. [University of Massachusetts, Amherst, Department of Physics (United States); Kawamura, N.; Koda, A.; Kojima, K. M. [KEK (Japan); Kubo, M. K. [International Christian University, Graduate School of Arts and Science (Japan); Matsuda, Y. [University of Tokyo, Graduate School of Arts and Sciences (Japan); Mibe, T. [KEK (Japan); and others

2017-11-15

MuSEUM is an international collaboration aiming at a new precise measurement of the muonium hyperfine structure at J-PARC (Japan Proton Accelerator Research Complex). Utilizing its intense pulsed muon beam, we expect a ten-fold improvement for both measurements at high magnetic field and zero magnetic field. We have developed a sophisticated monitoring system, including a beam profile monitor to measure the 3D distribution of muonium atoms to suppress the systematic uncertainty.

Fiber Scrambling for High Precision Spectrographs

Science.gov (United States)

Kaplan, Zachary; Spronck, J. F. P.; Fischer, D.

2011-05-01

The detection of Earth-like exoplanets with the radial velocity method requires extreme Doppler precision and long-term stability in order to measure tiny reflex velocities in the host star. Recent planet searches have led to the detection of so called "super-Earths” (up to a few Earth masses) that induce radial velocity changes of about 1 m/s. However, the detection of true Earth analogs requires a precision of 10 cm/s. One of the largest factors limiting Doppler precision is variation in the Point Spread Function (PSF) from observation to observation due to changes in the illumination of the slit and spectrograph optics. Thus, this stability has become a focus of current instrumentation work. Fiber optics have been used since the 1980's to couple telescopes to high-precision spectrographs, initially for simpler mechanical design and control. However, fiber optics are also naturally efficient scramblers. Scrambling refers to a fiber's ability to produce an output beam independent of input. Our research is focused on characterizing the scrambling properties of several types of fibers, including circular, square and octagonal fibers. By measuring the intensity distribution after the fiber as a function of input beam position, we can simulate guiding errors that occur at an observatory. Through this, we can determine which fibers produce the most uniform outputs for the severest guiding errors, improving the PSF and allowing sub-m/s precision. However, extensive testing of fibers of supposedly identical core diameter, length and shape from the same manufacturer has revealed the "personality” of individual fibers. Personality describes differing intensity patterns for supposedly duplicate fibers illuminated identically. Here, we present our results on scrambling characterization as a function of fiber type, while studying individual fiber personality.

Proportional wire chamber system for beam definition in precision total cross section measurements

International Nuclear Information System (INIS)

Carroll, A.S.; Chiang, I.H.; Kycia, T.F.

1978-03-01

A PWC system was developed and extensively used in precision measurements of total cross sections at low momenta (0.4 to 1.1 GeV/c) and at high momenta (23 to 370 GeV/c). This ''electronic collimator'' operated simultaneously in a fast (250 nsec) decision making mode, and a slower (0.5 msec) readout mode. The decision making mode utilized adjustable hard-wired logic to define acceptable incident beam trajectories and reject multiple beam tracks. A sample of the events were read into an on-line computer for beam tuning, for chamber diagnostics, and for study of the effect of small angle scattering to verify the total cross section extrapolation procedure

A Flexure-Based Mechanism for Precision Adjustment of National Ignition Facility Target Shrouds in Three Rotational Degrees of Freedom

International Nuclear Information System (INIS)

Boehm, K.-J.; Gibson, C. R.; Hollaway, J. R.; Espinoza-Loza, F.

2016-01-01

This study presents the design of a flexure-based mount allowing adjustment in three rotational degrees of freedom (DOFs) through high-precision set-screw actuators. The requirements of the application called for small but controlled angular adjustments for mounting a cantilevered beam. The proposed design is based on an array of parallel beams to provide sufficiently high stiffness in the translational directions while allowing angular adjustment through the actuators. A simplified physical model in combination with standard beam theory was applied to estimate the deflection profile and maximum stresses in the beams. A finite element model was built to calculate the stresses and beam profiles for scenarios in which the flexure is simultaneously actuated in more than one DOF.

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)

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

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

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.

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

Towards precise classification of cancers based on robust gene functional expression profiles

Directory of Open Access Journals (Sweden)

Zhu Jing

2005-03-01

Full Text Available Abstract Background Development of robust and efficient methods for analyzing and interpreting high dimension gene expression profiles continues to be a focus in computational biology. The accumulated experiment evidence supports the assumption that genes express and perform their functions in modular fashions in cells. Therefore, there is an open space for development of the timely and relevant computational algorithms that use robust functional expression profiles towards precise classification of complex human diseases at the modular level. Results Inspired by the insight that genes act as a module to carry out a highly integrated cellular function, we thus define a low dimension functional expression profile for data reduction. After annotating each individual gene to functional categories defined in a proper gene function classification system such as Gene Ontology applied in this study, we identify those functional categories enriched with differentially expressed genes. For each functional category or functional module, we compute a summary measure (s for the raw expression values of the annotated genes to capture the overall activity level of the module. In this way, we can treat the gene expressions within a functional module as an integrative data point to replace the multiple values of individual genes. We compare the classification performance of decision trees based on functional expression profiles with the conventional gene expression profiles using four publicly available datasets, which indicates that precise classification of tumour types and improved interpretation can be achieved with the reduced functional expression profiles. Conclusion This modular approach is demonstrated to be a powerful alternative approach to analyzing high dimension microarray data and is robust to high measurement noise and intrinsic biological variance inherent in microarray data. Furthermore, efficient integration with current biological knowledge

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).

Automated translating beam profiler for in situ laser beam spot-size and focal position measurements

Science.gov (United States)

Keaveney, James

2018-03-01

We present a simple and convenient, high-resolution solution for automated laser-beam profiling with axial translation. The device is based on a Raspberry Pi computer, Pi Noir CMOS camera, stepper motor, and commercial translation stage. We also provide software to run the device. The CMOS sensor is sensitive over a large wavelength range between 300 and 1100 nm and can be translated over 25 mm along the beam axis. The sensor head can be reversed without changing its axial position, allowing for a quantitative estimate of beam overlap with counter-propagating laser beams. Although not limited to this application, the intended use for this device is the automated measurement of the focal position and spot-size of a Gaussian laser beam. We present example data of one such measurement to illustrate device performance.

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

A proportional wire chamber system for beam definition in precision total cross section measurements

International Nuclear Information System (INIS)

Carroll, A.S.; Chiang, I.-H.; Kycia, T.F.; Li, K.K.; Mazur, P.O.; Michael, D.N.; Mockett, P.M.; Rahm, D.C.; Rubinstein, R.; Eartly, D.P.; Wehmann, A.A.

1978-01-01

The authors have developed and extensively used a PWC system in precision measurements of total cross sections at low momenta (0.4-1.1 GeV/c) and at high momenta (23-370 GeV/c). This 'electronic collimator' operated simultaneously in a fast (250 ns) decision making mode, and a slower (0.5 ms) readout mode. The decision making mode utilized adjustable hardwired logic to define acceptable incident beam trajectories and reject multiple beam tracks. A sample of the events was read into an on-line computer for beam tuning, for chamber diagnostics, and for study of the effect of small angle scattering to verify the total cross section extrapolation procedure. (Auth.)

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

High Precision Beam Diagnostics for Ion Thrusters

NARCIS (Netherlands)

Van Reijen, B.; Koch, N.; Lazurenko, A.; Weis, S.; Schirra, M.; Genovese, A.; Haderspeck, J.; Gill, E.K.A.

2011-01-01

The Thales diagnostic equipment for ion beam characterization consists of a gridded and single orifice retarding potential analyzer (RPA) and an energy selective mass spectrometer (ESMS). During the development phase of these sensors considerable effort was put into the removal of ion optical

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.

High precision target center determination from a point cloud

Directory of Open Access Journals (Sweden)

K. Kregar

2013-10-01

Full Text Available Many applications of terrestrial laser scanners (TLS require the determination of a specific point from a point cloud. In this paper procedure of high precision planar target center acquisition from point cloud is presented. The process is based on an image matching algorithm but before we can deal with raster image to fit a target on it, we need to properly determine the best fitting plane and project points on it. The main emphasis of this paper is in the precision estimation and propagation through the whole procedure which allows us to obtain precision assessment of final results (target center coordinates. Theoretic precision estimations – obtained through the procedure were rather high so we compared them with the empiric precision estimations obtained as standard deviations of results of 60 independently scanned targets. An χ2-test confirmed that theoretic precisions are overestimated. The problem most probably lies in the overestimated precisions of the plane parameters due to vast redundancy of points. However, empirical precisions also confirmed that the proposed procedure can ensure a submillimeter precision level. The algorithm can automatically detect grossly erroneous results to some extent. It can operate when the incidence angles of a laser beam are as high as 80°, which is desirable property if one is going to use planar targets as tie points in scan registration. The proposed algorithm will also contribute to improve TLS calibration procedures.

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

Mechanical optimisation of a high-precision fast wire scanner at CERN

CERN Document Server

Samuelsson, Sebastian; Veness, Raymond

Wire scanners are instruments used to measure the transverse beam prole in particle accelerators by passing a thin wire through the particle beam. To avoid the issues of vacuum leakage through the bellows and wire failure related to current designs of wire scanners, a new concept for a wire scanner has been developed at CERN. This design has all moving parts inside the beam vacuum and has a nominal wire scanning speed of 20 m/s. The demands on the design associated with this together with the high precision requirements create a need for\

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)

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

Beam shaping to provide round and square-shaped beams in optical systems of high-power lasers

Science.gov (United States)

Laskin, Alexander; Laskin, Vadim

2016-05-01

Optical systems of modern high-power lasers require control of irradiance distribution: round or square-shaped flat-top or super-Gaussian irradiance profiles are optimum for amplification in MOPA lasers and for thermal load management while pumping of crystals of solid-state ultra-short pulse lasers to control heat and minimize its impact on the laser power and beam quality while maximizing overall laser efficiency, variable profiles are also important in irradiating of photocathode of Free Electron lasers (FEL). It is suggested to solve the task of irradiance re-distribution using field mapping refractive beam shapers like piShaper. The operational principle of these devices presumes transformation of laser beam intensity from Gaussian to flat-top one with high flatness of output wavefront, saving of beam consistency, providing collimated output beam of low divergence, high transmittance, extended depth of field, negligible residual wave aberration, and achromatic design provides capability to work with ultra-short pulse lasers having broad spectrum. Using the same piShaper device it is possible to realize beams with flat-top, inverse Gauss or super Gauss irradiance distribution by simple variation of input beam diameter, and the beam shape can be round or square with soft edges. This paper will describe some design basics of refractive beam shapers of the field mapping type and optical layouts of their applying in optical systems of high-power lasers. Examples of real implementations and experimental results will be presented as well.

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.

Adaptive electron beam shaping using a photoemission gun and spatial light modulator

Science.gov (United States)

Maxson, Jared; Lee, Hyeri; Bartnik, Adam C.; Kiefer, Jacob; Bazarov, Ivan

2015-02-01

The need for precisely defined beam shapes in photoelectron sources has been well established. In this paper, we use a spatial light modulator and simple shaping algorithm to create arbitrary, detailed transverse laser shapes with high fidelity. We transmit this shaped laser to the photocathode of a high voltage dc gun. Using beam currents where space charge is negligible, and using an imaging solenoid and fluorescent viewscreen, we show that the resultant beam shape preserves these detailed features with similar fidelity. Next, instead of transmitting a shaped laser profile, we use an active feedback on the unshaped electron beam image to create equally accurate and detailed shapes. We demonstrate that this electron beam feedback has the added advantage of correcting for electron optical aberrations, yielding shapes without skew. The method may serve to provide precisely defined electron beams for low current target experiments, space-charge dominated beam commissioning, as well as for online adaptive correction of photocathode quantum efficiency degradation.

Adaptive electron beam shaping using a photoemission gun and spatial light modulator

Directory of Open Access Journals (Sweden)

Jared Maxson

2015-02-01

Full Text Available The need for precisely defined beam shapes in photoelectron sources has been well established. In this paper, we use a spatial light modulator and simple shaping algorithm to create arbitrary, detailed transverse laser shapes with high fidelity. We transmit this shaped laser to the photocathode of a high voltage dc gun. Using beam currents where space charge is negligible, and using an imaging solenoid and fluorescent viewscreen, we show that the resultant beam shape preserves these detailed features with similar fidelity. Next, instead of transmitting a shaped laser profile, we use an active feedback on the unshaped electron beam image to create equally accurate and detailed shapes. We demonstrate that this electron beam feedback has the added advantage of correcting for electron optical aberrations, yielding shapes without skew. The method may serve to provide precisely defined electron beams for low current target experiments, space-charge dominated beam commissioning, as well as for online adaptive correction of photocathode quantum efficiency degradation.

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.

Inland and Near-Shore Water Profiles Derived from the High-Altitude Multiple Altimeter Beam Experimental Lidar (MABEL)

Science.gov (United States)

Jasinski, Michael F.; Stoll, Jeremy D.; Cook, William B.; Ondrusek, Michael; Stengel, Eric; Brunt, Kelly

2016-01-01

The Advanced Topographic Laser Altimeter System (ATLAS) on the Ice, Cloud, and Land Elevation Satellite (ICESat-2) mission is a six beam, low energy, high repetition rate, 532-nanometer laser transmitter with photon counting detectors. Although designed primarily for detecting height changes in ice caps, sea ice, and vegetation, the polar-orbiting satellite will observe global surface water during its designed three-year life span, including inland waterbodies, coasts, and open oceans. In preparation for the mission, an ICESat-2 prototype, the Multiple Altimeter Beam Experimental Lidar (MABEL), was built and flown on high-altitude aircraft experiments over a range of inland and near-shore targets. The purpose was to test the ATLAS concept and to provide a database for developing an algorithm that detects along track surface water height and light penetration under a range of atmospheric and water conditions. The current analysis examines the data sets of three MABEL transects observed from 20 kilometers above ground of coastal and inland waters conducted in 2012 and 2013. Transects ranged from about 2 to 12 kilometers in length and included the middle Chesapeake Bay, the near-shore Atlantic coast at Virginia Beach, and Lake Mead. Results indicate MABEL's high capability for retrieving surface water height statistics with a mean height precision ofapproximately 5-7 centimeters per 100-meter segment length. Profiles of attenuated subsurface backscatter, characterized using a Signal to Background Ratio written in Log10 base, or LSBR (sub 0), were observed over a range of 1.3 to 9.3 meters, depending on water clarity and atmospheric background. Results indicate that observable penetration depth, although primarily dependent on water properties, was greatest when the solar background rate was low. Near-shore bottom reflectance was detected only at the Lake Mead site down to a maximum of 10 meters under a clear night sky and low turbidity of approximately 1

High precision determination of 16O in high Tc superconductors by DIGME

International Nuclear Information System (INIS)

Vickridge, I.; Tallon, J.; Presland, M.

1994-01-01

A method is described for measuring the 16 O content of high T c superconductors with better than 1% precision by exploiting the detection of gamma rays emitted when they are irradiated by an MeV deuterium beam. The method is presently less accurate than the widely used titration and thermogravimetric methods, however it is rapid, and may be applied to materials such as Tl-containing high T c superconductors which pose serious problems for the usual analytical methods. (orig.)

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.

Generation of annular, high-charge electron beams at the Argonne wakefield accelerator

Science.gov (United States)

Wisniewski, E. E.; Li, C.; Gai, W.; Power, J.

2013-01-01

We present and discuss the results from the experimental generation of high-charge annular(ring-shaped)electron beams at the Argonne Wakefield Accelerator (AWA). These beams were produced by using laser masks to project annular laser profiles of various inner and outer diameters onto the photocathode of an RF gun. The ring beam is accelerated to 15 MeV, then it is imaged by means of solenoid lenses. Transverse profiles are compared for different solenoid settings. Discussion includes a comparison with Parmela simulations, some applications of high-charge ring beams,and an outline of a planned extension of this study.

Generation of annular, high-charge electron beams at the Argonne wakefield accelerator

Science.gov (United States)

Wisniewski, E. E.; Li, C.; Gai, W.; Power, J.

2012-12-01

We present and discuss the results from the experimental generation of high-charge annular(ring-shaped)electron beams at the Argonne Wakefield Accelerator (AWA). These beams were produced by using laser masks to project annular laser profiles of various inner and outer diameters onto the photocathode of an RF gun. The ring beam is accelerated to 15 MeV, then it is imaged by means of solenoid lenses. Transverse profiles are compared for different solenoid settings. Discussion includes a comparison with Parmela simulations, some applications of high-charge ring beams,and an outline of a planned extension of this study.

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.

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.

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.

Precision atomic beam density characterization by diode laser absorption spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Oxley, Paul; Wihbey, Joseph [Physics Department, The College of the Holy Cross, Worcester, Massachusetts 01610 (United States)

2016-09-15

We provide experimental and theoretical details of a simple technique to determine absolute line-of-sight integrated atomic beam densities based on resonant laser absorption. In our experiments, a thermal lithium beam is chopped on and off while the frequency of a laser crossing the beam at right angles is scanned slowly across the resonance transition. A lock-in amplifier detects the laser absorption signal at the chop frequency from which the atomic density is determined. The accuracy of our experimental method is confirmed using the related technique of wavelength modulation spectroscopy. For beams which absorb of order 1% of the incident laser light, our measurements allow the beam density to be determined to an accuracy better than 5% and with a precision of 3% on a time scale of order 1 s. Fractional absorptions of order 10{sup −5} are detectable on a one-minute time scale when we employ a double laser beam technique which limits laser intensity noise. For a lithium beam with a thickness of 9 mm, we have measured atomic densities as low as 5 × 10{sup 4} atoms cm{sup −3}. The simplicity of our technique and the details we provide should allow our method to be easily implemented in most atomic or molecular beam apparatuses.

Precision atomic beam density characterization by diode laser absorption spectroscopy

International Nuclear Information System (INIS)

Oxley, Paul; Wihbey, Joseph

2016-01-01

We provide experimental and theoretical details of a simple technique to determine absolute line-of-sight integrated atomic beam densities based on resonant laser absorption. In our experiments, a thermal lithium beam is chopped on and off while the frequency of a laser crossing the beam at right angles is scanned slowly across the resonance transition. A lock-in amplifier detects the laser absorption signal at the chop frequency from which the atomic density is determined. The accuracy of our experimental method is confirmed using the related technique of wavelength modulation spectroscopy. For beams which absorb of order 1% of the incident laser light, our measurements allow the beam density to be determined to an accuracy better than 5% and with a precision of 3% on a time scale of order 1 s. Fractional absorptions of order 10 −5 are detectable on a one-minute time scale when we employ a double laser beam technique which limits laser intensity noise. For a lithium beam with a thickness of 9 mm, we have measured atomic densities as low as 5 × 10 4 atoms cm −3 . The simplicity of our technique and the details we provide should allow our method to be easily implemented in most atomic or molecular beam apparatuses.

Precision atomic beam density characterization by diode laser absorption spectroscopy.

Science.gov (United States)

Oxley, Paul; Wihbey, Joseph

2016-09-01

We provide experimental and theoretical details of a simple technique to determine absolute line-of-sight integrated atomic beam densities based on resonant laser absorption. In our experiments, a thermal lithium beam is chopped on and off while the frequency of a laser crossing the beam at right angles is scanned slowly across the resonance transition. A lock-in amplifier detects the laser absorption signal at the chop frequency from which the atomic density is determined. The accuracy of our experimental method is confirmed using the related technique of wavelength modulation spectroscopy. For beams which absorb of order 1% of the incident laser light, our measurements allow the beam density to be determined to an accuracy better than 5% and with a precision of 3% on a time scale of order 1 s. Fractional absorptions of order 10 -5 are detectable on a one-minute time scale when we employ a double laser beam technique which limits laser intensity noise. For a lithium beam with a thickness of 9 mm, we have measured atomic densities as low as 5 × 10 4 atoms cm -3 . The simplicity of our technique and the details we provide should allow our method to be easily implemented in most atomic or molecular beam apparatuses.

Diode line scanner for beam diagnostics

International Nuclear Information System (INIS)

Gustov, S.A.

1987-01-01

The device-scanning diode line is described. It is applied for beam profile measuring with space precision better than ± 0.5 mm and with discreteness of 3 mm along Y-axis and 0.25 mm along X-axis. The device is easy in construction, reliable and has a small time of information acquisition (2-5 min). The working range is from 100 to 10 6 rad/min (10 6 -10 10 part/mm 2 /s for 660 MeV protons). Radioresistance is 10 7 rad. The device can be applied for precise beam line element tuning at beam transporting and emittance measuring. The fixed diode line (a simplified device version) has smaller dimensions and smaller time of data acquisition (2-5 s). It is applied for quick preliminary beamline tuning. The flowsheet and different variants of data representation on beam profile are given

Today's status of application of high power electron beam welding to heavy electric machinery

International Nuclear Information System (INIS)

Kita, Hisanao; Okuni, Tetsuo; Sejima, Itsuhiko.

1980-01-01

The progress in high energy welding is remarkable in recent years, and electron beam welding is now widely used in heavy industries. However, there are number of problems to be solved in the application of high power electron beam welding to ultra thick steel plates (over 100 mm). The following matters are described: the economy of high power electron beam welding; the development of the welding machines; the problems in the actual application; the instances of the welding in a high-pressure spherical gas tank, non-magnetic steel structures and high-precision welded structures; weldor training; etc. For the future rise in the capacities of heavy electric machinery, the high efficiency by high power electron beam welding will be useful. The current status is its applications to the high-precision welding of large structures with 6 m diameter and the high-quality welding of heavy structures with 160 mm thickness. (J.P.N.)

Design and algorithm research of high precision airborne infrared touch screen

Science.gov (United States)

Zhang, Xiao-Bing; Wang, Shuang-Jie; Fu, Yan; Chen, Zhao-Quan

2016-10-01

There are shortcomings of low precision, touch shaking, and sharp decrease of touch precision when emitting and receiving tubes are failure in the infrared touch screen. A high precision positioning algorithm based on extended axis is proposed to solve these problems. First, the unimpeded state of the beam between emitting and receiving tubes is recorded as 0, while the impeded state is recorded as 1. Then, the method of oblique scan is used, in which the light of one emitting tube is used for five receiving tubes. The impeded information of all emitting and receiving tubes is collected as matrix. Finally, according to the method of arithmetic average, the position of the touch object is calculated. The extended axis positioning algorithm is characteristic of high precision in case of failure of individual infrared tube and affects slightly the precision. The experimental result shows that the 90% display area of the touch error is less than 0.25D, where D is the distance between adjacent emitting tubes. The conclusion is gained that the algorithm based on extended axis has advantages of high precision, little impact when individual infrared tube is failure, and using easily.

Theory, simulation and experiments for precise deflection control of radiotherapy electron beams

Energy Technology Data Exchange (ETDEWEB)

Figueroa, R.; Leiva, J.; Moncada, R.; Rojas, L.; Santibanez, M.; Valente, M.; Young, H. [Universidad de la Frontera, Centro de Fisica e Ingenieria en Medicina, Av. Francisco Salazar 1145, Casilla 54-D, Temuco (Chile); Velasquez, J. [Universidad de la Frontera, Departamento de Ciencias Fisicas, Av. Francisco Salazar 1145, Casilla 54-D, Temuco (Chile); Zelada, G. [Clinica Alemana de Santiago, Av. Vitacura 5951, 13132 Vitacura, Santiago (Chile); Astudillo, R., E-mail: rodolfo.figueroa@ufrontera.cl [Hospital Base de Valdivia, C. Simpson 850, XIV Region de los Rios, Valdivia (Chile)

2017-10-15

Conventional radiotherapy is mainly applied by linear accelerators. Although linear accelerators provide dual (electron/photon) radiation beam modalities, both of them are intrinsically produced by a megavoltage electron current. Modern radiotherapy treatment techniques are based on suitable devices inserted or attached to conventional linear accelerators. Thus, precise control of delivered beam becomes a main key issue. This work presents an integral description of electron beam deflection control as required for novel radiotherapy technique based on convergent photon beam production. Theoretical and Monte Carlo approaches were initially used for designing and optimizing devices components. Then, dedicated instrumentation was developed for experimental verification of electron beam deflection due to the designed magnets. Both Monte Carlo simulations and experimental results support the reliability of electrodynamics models used for predict megavoltage electron beam control. (Author)

Theory, simulation and experiments for precise deflection control of radiotherapy electron beams

International Nuclear Information System (INIS)

Figueroa, R.; Leiva, J.; Moncada, R.; Rojas, L.; Santibanez, M.; Valente, M.; Young, H.; Velasquez, J.; Zelada, G.; Astudillo, R.

2017-10-01

Conventional radiotherapy is mainly applied by linear accelerators. Although linear accelerators provide dual (electron/photon) radiation beam modalities, both of them are intrinsically produced by a megavoltage electron current. Modern radiotherapy treatment techniques are based on suitable devices inserted or attached to conventional linear accelerators. Thus, precise control of delivered beam becomes a main key issue. This work presents an integral description of electron beam deflection control as required for novel radiotherapy technique based on convergent photon beam production. Theoretical and Monte Carlo approaches were initially used for designing and optimizing devices components. Then, dedicated instrumentation was developed for experimental verification of electron beam deflection due to the designed magnets. Both Monte Carlo simulations and experimental results support the reliability of electrodynamics models used for predict megavoltage electron beam control. (Author)

Precision luminosity measurements at LHCb

CERN Document Server

Aaij, Roel; Adinolfi, Marco; Affolder, Anthony; Ajaltouni, Ziad; Akar, Simon; Albrecht, Johannes; Alessio, Federico; Alexander, Michael; Ali, Suvayu; Alkhazov, Georgy; Alvarez Cartelle, Paula; Alves Jr, Antonio Augusto; Amato, Sandra; Amerio, Silvia; Amhis, Yasmine; An, Liupan; Anderlini, Lucio; Anderson, Jonathan; Andreassen, Rolf; Andreotti, Mirco; Andrews, Jason; Appleby, Robert; Aquines Gutierrez, Osvaldo; Archilli, Flavio; Artamonov, Alexander; Artuso, Marina; Aslanides, Elie; Auriemma, Giulio; Baalouch, Marouen; Bachmann, Sebastian; Back, John; Badalov, Alexey; Baesso, Clarissa; Baldini, Wander; Barlow, Roger; Barschel, Colin; Barsuk, Sergey; Barter, William; Batozskaya, Varvara; Battista, Vincenzo; Bay, Aurelio; Beaucourt, Leo; Beddow, John; Bedeschi, Franco; Bediaga, Ignacio; Belogurov, Sergey; Belous, Konstantin; Belyaev, Ivan; Ben-Haim, Eli; Bencivenni, Giovanni; Benson, Sean; Benton, Jack; Berezhnoy, Alexander; Bernet, Roland; Bettler, Marc-Olivier; van Beuzekom, Martinus; Bien, Alexander; Bifani, Simone; Bird, Thomas; Bizzeti, Andrea; Bjørnstad, Pål Marius; Blake, Thomas; Blanc, Frédéric; Blouw, Johan; Blusk, Steven; Bocci, Valerio; Bondar, Alexander; Bondar, Nikolay; Bonivento, Walter; Borghi, Silvia; Borgia, Alessandra; Borsato, Martino; Bowcock, Themistocles; Bowen, Espen Eie; Bozzi, Concezio; Brambach, Tobias; Bressieux, Joël; Brett, David; Britsch, Markward; Britton, Thomas; Brodzicka, Jolanta; Brook, Nicholas; Brown, Henry; Bursche, Albert; Buytaert, Jan; Cadeddu, Sandro; Calabrese, Roberto; Calvi, Marta; Calvo Gomez, Miriam; Campana, Pierluigi; Campora Perez, Daniel; Carbone, Angelo; Carboni, Giovanni; Cardinale, Roberta; Cardini, Alessandro; Carson, Laurence; Carvalho Akiba, Kazuyoshi; Casse, Gianluigi; Cassina, Lorenzo; Castillo Garcia, Lucia; Cattaneo, Marco; Cauet, Christophe; Cenci, Riccardo; Charles, Matthew; Charpentier, Philippe; Chefdeville, Maximilien; Chen, Shanzhen; Cheung, Shu-Faye; Chiapolini, Nicola; Chrzaszcz, Marcin; Ciba, Krzystof; Cid Vidal, Xabier; Ciezarek, Gregory; Clarke, Peter; Clemencic, Marco; Cliff, Harry; Closier, Joel; Coco, Victor; Cogan, Julien; Cogneras, Eric; Cojocariu, Lucian; Collazuol, Gianmaria; Collins, Paula; Comerma-Montells, Albert; Contu, Andrea; Cook, Andrew; Coombes, Matthew; Coquereau, Samuel; Corti, Gloria; Corvo, Marco; Counts, Ian; Couturier, Benjamin; Cowan, Greig; Craik, Daniel Charles; Cruz Torres, Melissa Maria; Cunliffe, Samuel; Currie, Robert; D'Ambrosio, Carmelo; Dalseno, Jeremy; David, Pascal; David, Pieter; Davis, Adam; De Bruyn, Kristof; De Capua, Stefano; De Cian, Michel; De Miranda, Jussara; De Paula, Leandro; De Silva, Weeraddana; De Simone, Patrizia; Dean, Cameron Thomas; Decamp, Daniel; Deckenhoff, Mirko; Del Buono, Luigi; Déléage, Nicolas; Derkach, Denis; Deschamps, Olivier; Dettori, Francesco; Di Canto, Angelo; Dijkstra, Hans; Donleavy, Stephanie; Dordei, Francesca; Dorigo, Mirco; Dosil Suárez, Alvaro; Dossett, David; Dovbnya, Anatoliy; Dreimanis, Karlis; Dujany, Giulio; Dupertuis, Frederic; Durante, Paolo; Dzhelyadin, Rustem; Dziurda, Agnieszka; Dzyuba, Alexey; Easo, Sajan; Egede, Ulrik; Egorychev, Victor; Eidelman, Semen; Eisenhardt, Stephan; Eitschberger, Ulrich; Ekelhof, Robert; Eklund, Lars; El Rifai, Ibrahim; Elsasser, Christian; Ely, Scott; Esen, Sevda; Evans, Hannah Mary; Evans, Timothy; Falabella, Antonio; Färber, Christian; Farinelli, Chiara; Farley, Nathanael; Farry, Stephen; Fay, Robert; Ferguson, Dianne; Fernandez Albor, Victor; Ferreira Rodrigues, Fernando; Ferro-Luzzi, Massimiliano; Filippov, Sergey; Fiore, Marco; Fiorini, Massimiliano; Firlej, Miroslaw; Fitzpatrick, Conor; Fiutowski, Tomasz; Fol, Philip; Fontana, Marianna; Fontanelli, Flavio; Forty, Roger; Francisco, Oscar; Frank, Markus; Frei, Christoph; Frosini, Maddalena; Fu, Jinlin; Furfaro, Emiliano; Gallas Torreira, Abraham; Galli, Domenico; Gallorini, Stefano; Gambetta, Silvia; Gandelman, Miriam; Gandini, Paolo; Gao, Yuanning; García Pardiñas, Julián; Garofoli, Justin; Garra Tico, Jordi; Garrido, Lluis; Gascon, David; Gaspar, Clara; Gauld, Rhorry; Gavardi, Laura; Geraci, Angelo; Gersabeck, Evelina; Gersabeck, Marco; Gershon, Timothy; Ghez, Philippe; Gianelle, Alessio; Gianì, Sebastiana; Gibson, Valerie; Giubega, Lavinia-Helena; Gligorov, V.V.; Göbel, Carla; Golubkov, Dmitry; Golutvin, Andrey; Gomes, Alvaro; Gotti, Claudio; Grabalosa Gándara, Marc; Graciani Diaz, Ricardo; Granado Cardoso, Luis Alberto; Graugés, Eugeni; Graziani, Giacomo; Grecu, Alexandru; Greening, Edward; Gregson, Sam; Griffith, Peter; Grillo, Lucia; Grünberg, Oliver; Gui, Bin; Gushchin, Evgeny; Guz, Yury; Gys, Thierry; Hadjivasiliou, Christos; Haefeli, Guido; Haen, Christophe; Haines, Susan; Hall, Samuel; Hamilton, Brian; Hampson, Thomas; Han, Xiaoxue; Hansmann-Menzemer, Stephanie; Harnew, Neville; Harnew, Samuel; Harrison, Jonathan; He, Jibo; Head, Timothy; Heijne, Veerle; Hennessy, Karol; Henrard, Pierre; Henry, Louis; Hernando Morata, Jose Angel; van Herwijnen, Eric; Heß, Miriam; Hicheur, Adlène; Hill, Donal; Hoballah, Mostafa; Hombach, Christoph; Hulsbergen, Wouter; Hunt, Philip; Hussain, Nazim; Hutchcroft, David; Hynds, Daniel; Idzik, Marek; Ilten, Philip; Jacobsson, Richard; Jaeger, Andreas; Jalocha, Pawel; Jans, Eddy; Jaton, Pierre; Jawahery, Abolhassan; Jing, Fanfan; John, Malcolm; Johnson, Daniel; Jones, Christopher; Joram, Christian; Jost, Beat; Jurik, Nathan; Kandybei, Sergii; Kanso, Walaa; Karacson, Matthias; Karbach, Moritz; Karodia, Sarah; Kelsey, Matthew; Kenyon, Ian; Ketel, Tjeerd; Khanji, Basem; Khurewathanakul, Chitsanu; Klaver, Suzanne; Klimaszewski, Konrad; Kochebina, Olga; Kolpin, Michael; Komarov, Ilya; Koopman, Rose; Koppenburg, Patrick; Korolev, Mikhail; Kozlinskiy, Alexandr; Kravchuk, Leonid; Kreplin, Katharina; Kreps, Michal; Krocker, Georg; Krokovny, Pavel; Kruse, Florian; Kucewicz, Wojciech; Kucharczyk, Marcin; Kudryavtsev, Vasily; Kurek, Krzysztof; Kvaratskheliya, Tengiz; La Thi, Viet Nga; Lacarrere, Daniel; Lafferty, George; Lai, Adriano; Lambert, Dean; Lambert, Robert W; Lanfranchi, Gaia; Langenbruch, Christoph; Langhans, Benedikt; Latham, Thomas; Lazzeroni, Cristina; Le Gac, Renaud; van Leerdam, Jeroen; Lees, Jean-Pierre; Lefèvre, Regis; Leflat, Alexander; Lefrançois, Jacques; Leo, Sabato; Leroy, Olivier; Lesiak, Tadeusz; Leverington, Blake; Li, Yiming; Likhomanenko, Tatiana; Liles, Myfanwy; Lindner, Rolf; Linn, Christian; Lionetto, Federica; Liu, Bo; Lohn, Stefan; Longstaff, Iain; Lopes, Jose; Lopez-March, Neus; Lowdon, Peter; Lu, Haiting; Lucchesi, Donatella; Luo, Haofei; Lupato, Anna; Luppi, Eleonora; Lupton, Oliver; Machefert, Frederic; Machikhiliyan, Irina V; Maciuc, Florin; Maev, Oleg; Malde, Sneha; Malinin, Alexander; Manca, Giulia; Mancinelli, Giampiero; Mapelli, Alessandro; Maratas, Jan; Marchand, Jean François; Marconi, Umberto; Marin Benito, Carla; Marino, Pietro; Märki, Raphael; Marks, Jörg; Martellotti, Giuseppe; Martens, Aurelien; Martín Sánchez, Alexandra; Martinelli, Maurizio; Martinez Santos, Diego; Martinez Vidal, Fernando; Martins Tostes, Danielle; Massafferri, André; Matev, Rosen; Mathe, Zoltan; Matteuzzi, Clara; Maurin, Brice; Mazurov, Alexander; McCann, Michael; McCarthy, James; McNab, Andrew; McNulty, Ronan; McSkelly, Ben; Meadows, Brian; Meier, Frank; Meissner, Marco; Merk, Marcel; Milanes, Diego Alejandro; Minard, Marie-Noelle; Moggi, Niccolò; Molina Rodriguez, Josue; Monteil, Stephane; Morandin, Mauro; Morawski, Piotr; Mordà, Alessandro; Morello, Michael Joseph; Moron, Jakub; Morris, Adam Benjamin; Mountain, Raymond; Muheim, Franz; Müller, Katharina; Mussini, Manuel; Muster, Bastien; Naik, Paras; Nakada, Tatsuya; Nandakumar, Raja; Nasteva, Irina; Needham, Matthew; Neri, Nicola; Neubert, Sebastian; Neufeld, Niko; Neuner, Max; Nguyen, Anh Duc; Nguyen, Thi-Dung; Nguyen-Mau, Chung; Nicol, Michelle; Niess, Valentin; Niet, Ramon; Nikitin, Nikolay; Nikodem, Thomas; Novoselov, Alexey; O'Hanlon, Daniel Patrick; Oblakowska-Mucha, Agnieszka; Obraztsov, Vladimir; Oggero, Serena; Ogilvy, Stephen; Okhrimenko, Oleksandr; Oldeman, Rudolf; Onderwater, Gerco; Orlandea, Marius; Otalora Goicochea, Juan Martin; Owen, Patrick; Oyanguren, Maria Arantza; Pal, Bilas Kanti; Palano, Antimo; Palombo, Fernando; Palutan, Matteo; Panman, Jacob; Papanestis, Antonios; Pappagallo, Marco; Pappalardo, Luciano; Parkes, Christopher; Parkinson, Christopher John; Passaleva, Giovanni; Patel, Girish; Patel, Mitesh; Patrignani, Claudia; Pearce, Alex; Pellegrino, Antonio; Pepe Altarelli, Monica; Perazzini, Stefano; Perret, Pascal; Perrin-Terrin, Mathieu; Pescatore, Luca; Pesen, Erhan; Pessina, Gianluigi; Petridis, Konstantin; Petrolini, Alessandro; Picatoste Olloqui, Eduardo; Pietrzyk, Boleslaw; Pilař, Tomas; Pinci, Davide; Pistone, Alessandro; Playfer, Stephen; Plo Casasus, Maximo; Polci, Francesco; Poluektov, Anton; Polycarpo, Erica; Popov, Alexander; Popov, Dmitry; Popovici, Bogdan; Potterat, Cédric; Price, Eugenia; Price, Joseph David; Prisciandaro, Jessica; Pritchard, Adrian; Prouve, Claire; Pugatch, Valery; Puig Navarro, Albert; Punzi, Giovanni; Qian, Wenbin; Rachwal, Bartolomiej; Rademacker, Jonas; Rakotomiaramanana, Barinjaka; Rama, Matteo; Rangel, Murilo; Raniuk, Iurii; Rauschmayr, Nathalie; Raven, Gerhard; Redi, Federico; Reichert, Stefanie; Reid, Matthew; dos Reis, Alberto; Ricciardi, Stefania; Richards, Sophie; Rihl, Mariana; Rinnert, Kurt; Rives Molina, Vincente; Robbe, Patrick; Rodrigues, Ana Barbara; Rodrigues, Eduardo; Rodriguez Perez, Pablo; Roiser, Stefan; Romanovsky, Vladimir; Romero Vidal, Antonio; Rotondo, Marcello; Rouvinet, Julien; Ruf, Thomas; Ruiz, Hugo; Ruiz Valls, Pablo; Saborido Silva, Juan Jose; Sagidova, Naylya; Sail, Paul; Saitta, Biagio; Salustino Guimaraes, Valdir; Sanchez Mayordomo, Carlos; Sanmartin Sedes, Brais; Santacesaria, Roberta; Santamarina Rios, Cibran; Santovetti, Emanuele; Sarti, Alessio; Satriano, Celestina; Satta, Alessia; Saunders, Daniel Martin; Savrina, Darya; Schiller, Manuel; Schindler, Heinrich; Schlupp, Maximilian; Schmelling, Michael; Schmidt, Burkhard; Schneider, Olivier; Schopper, Andreas; Schubiger, Maxime; Schune, Marie Helene; Schwemmer, Rainer; Sciascia, Barbara; Sciubba, Adalberto; Semennikov, Alexander; Sepp, Indrek; Serra, Nicola; Serrano, Justine; Sestini, Lorenzo; Seyfert, Paul; Shapkin, Mikhail; Shapoval, Illya; Shcheglov, Yury; Shears, Tara; Shekhtman, Lev; Shevchenko, Vladimir; Shires, Alexander; Silva Coutinho, Rafael; Simi, Gabriele; Sirendi, Marek; Skidmore, Nicola; Skwarnicki, Tomasz; Smith, Anthony; Smith, Edmund; Smith, Eluned; Smith, Jackson; Smith, Mark; Snoek, Hella; Sokoloff, Michael; Soler, Paul; Soomro, Fatima; Souza, Daniel; Souza De Paula, Bruno; Spaan, Bernhard; Sparkes, Ailsa; Spradlin, Patrick; Sridharan, Srikanth; Stagni, Federico; Stahl, Marian; Stahl, Sascha; Steinkamp, Olaf; Stenyakin, Oleg; Stevenson, Scott; Stoica, Sabin; Stone, Sheldon; Storaci, Barbara; Stracka, Simone; Straticiuc, Mihai; Straumann, Ulrich; Stroili, Roberto; Subbiah, Vijay Kartik; Sun, Liang; Sutcliffe, William; Swientek, Krzysztof; Swientek, Stefan; Syropoulos, Vasileios; Szczekowski, Marek; Szczypka, Paul; Szumlak, Tomasz; T'Jampens, Stephane; Teklishyn, Maksym; Tellarini, Giulia; Teubert, Frederic; Thomas, Christopher; Thomas, Eric; van Tilburg, Jeroen; Tisserand, Vincent; Tobin, Mark; Tolk, Siim; Tomassetti, Luca; Tonelli, Diego; Topp-Joergensen, Stig; Torr, Nicholas; Tournefier, Edwige; Tourneur, Stephane; Tran, Minh Tâm; Tresch, Marco; Trisovic, Ana; Tsaregorodtsev, Andrei; Tsopelas, Panagiotis; Tuning, Niels; Ubeda Garcia, Mario; Ukleja, Artur; Ustyuzhanin, Andrey; Uwer, Ulrich; Vacca, Claudia; Vagnoni, Vincenzo; Valenti, Giovanni; Vallier, Alexis; Vazquez Gomez, Ricardo; Vazquez Regueiro, Pablo; Vázquez Sierra, Carlos; Vecchi, Stefania; Velthuis, Jaap; Veltri, Michele; Veneziano, Giovanni; Vesterinen, Mika; Viaud, Benoit; Vieira, Daniel; Vieites Diaz, Maria; Vilasis-Cardona, Xavier; Vollhardt, Achim; Volyanskyy, Dmytro; Voong, David; Vorobyev, Alexey; Vorobyev, Vitaly; Voß, Christian; de Vries, Jacco; Waldi, Roland; Wallace, Charlotte; Wallace, Ronan; Walsh, John; Wandernoth, Sebastian; Wang, Jianchun; Ward, David; Watson, Nigel; Websdale, David; Whitehead, Mark; Wicht, Jean; Wiedner, Dirk; Wilkinson, Guy; Williams, Matthew; Williams, Mike; Wilschut, Hans; Wilson, Fergus; Wimberley, Jack; Wishahi, Julian; Wislicki, Wojciech; Witek, Mariusz; Wormser, Guy; Wotton, Stephen; Wright, Simon; Wyllie, Kenneth; Xie, Yuehong; Xing, Zhou; Xu, Zhirui; Yang, Zhenwei; Yuan, Xuhao; Yushchenko, Oleg; Zangoli, Maria; Zavertyaev, Mikhail; Zhang, Liming; Zhang, Wen Chao; Zhang, Yanxi; Zhelezov, Alexey; Zhokhov, Anatoly; Zhong, Liang; Zvyagin, Alexander

2014-12-05

Measuring cross-sections at the LHC requires the luminosity to be determined accurately at each centre-of-mass energy $\\sqrt{s}$. In this paper results are reported from the luminosity calibrations carried out at the LHC interaction point 8 with the LHCb detector for $\\sqrt{s}$ = 2.76, 7 and 8 TeV (proton-proton collisions) and for $\\sqrt{s_{NN}}$ = 5 TeV (proton-lead collisions). Both the "van der Meer scan" and "beam-gas imaging" luminosity calibration methods were employed. It is observed that the beam density profile cannot always be described by a function that is factorizable in the two transverse coordinates. The introduction of a two-dimensional description of the beams improves significantly the consistency of the results. For proton-proton interactions at $\\sqrt{s}$ = 8 TeV a relative precision of the luminosity calibration of 1.47% is obtained using van der Meer scans and 1.43% using beam-gas imaging, resulting in a combined precision of 1.12%. Applying the calibration to the full data set determin...

Polarisation and precise calibration of the LEP beam energy

CERN Document Server

Koutchouk, Jean-Pierre

2002-01-01

We report in this article on two issues of precision accelerator physics, performed at the LEP collider, that challenged international collaborations. The first result is an increase of the polarisation degree from an almost vanishing natural level to 50%, opening the way to energy calibration by resonant depolarisation. The second result is a systematic and precise determination of the collider centre-of- mass energy correcting for subtle effects such as the azimuthal variation of the beam energy, the magnet temperature, the effects of parasitic earth currents and terrestrial tides. It resulted in an extremely accurate test of the standard model and set significant constraints on the top quark and Higgs masses. (16 refs).

Precision electron polarimetry

International Nuclear Information System (INIS)

Chudakov, E.

2013-01-01

A new generation of precise Parity-Violating experiments will require a sub-percent accuracy of electron beam polarimetry. Compton polarimetry can provide such accuracy at high energies, but at a few hundred MeV the small analyzing power limits the sensitivity. Mo/ller polarimetry provides a high analyzing power independent on the beam energy, but is limited by the properties of the polarized targets commonly used. Options for precision polarimetry at 300 MeV will be discussed, in particular a proposal to use ultra-cold atomic hydrogen traps to provide a 100%-polarized electron target for Mo/ller polarimetry

High-Precision Half-Life Measurement for the Superallowed β+ Emitter Alm26

Science.gov (United States)

Finlay, P.; Ettenauer, S.; Ball, G. C.; Leslie, J. R.; Svensson, C. E.; Andreoiu, C.; Austin, R. A. E.; Bandyopadhyay, D.; Cross, D. S.; Demand, G.; Djongolov, M.; Garrett, P. E.; Green, K. L.; Grinyer, G. F.; Hackman, G.; Leach, K. G.; Pearson, C. J.; Phillips, A. A.; Sumithrarachchi, C. S.; Triambak, S.; Williams, S. J.

2011-01-01

A high-precision half-life measurement for the superallowed β+ emitter Alm26 was performed at the TRIUMF-ISAC radioactive ion beam facility yielding T1/2=6346.54±0.46stat±0.60systms, consistent with, but 2.5 times more precise than, the previous world average. The Alm26 half-life and ft value, 3037.53(61) s, are now the most precisely determined for any superallowed β decay. Combined with recent theoretical corrections for isospin-symmetry-breaking and radiative effects, the corrected Ft value for Alm26, 3073.0(12) s, sets a new benchmark for the high-precision superallowed Fermi β-decay studies used to test the conserved vector current hypothesis and determine the Vud element of the Cabibbo-Kobayashi-Maskawa quark mixing matrix.

Precision white-beam slit design for high power density x-ray undulator beamlines at the Advanced Photon Source

International Nuclear Information System (INIS)

Shu, D.; Brite, C.; Nian, T.

1994-01-01

A set of precision horizontal and vertical white-beam slits has been designed for the Advanced Photon Source (APS) X-ray undulator beamlines at Argonne National Laboratory. There are several new design concepts applied in this slit set, including: grazing-incidence knife-edge configuration to minimize the scattering of X-rays downstream, enhanced heat transfer tubing to provide water cooling, and a second slit to eliminate the thermal distortion on the slit knife edge. The novel aspect of this design is the use of two L-shaped knife-edge assemblies, which are manipulated by two precision X-Z stepping linear actuators. The principal and structural details of the design for this slit set are presented in this paper

Imaging high energy photons with PILATUS II at the tagged photon beam at MAX-lab

Energy Technology Data Exchange (ETDEWEB)

Lee, V. [School of Physics, University of Melbourne, Parkville 3010 (Australia)], E-mail: leev@physics.unimelb.edu.au; Peake, D.J.; Sobott, B. [School of Physics, University of Melbourne, Parkville 3010 (Australia); Schroeder, B. [MAX-lab, Lund University, Lund (Sweden); Broennimann, Ch. [DECTRIS Ltd., Baden (Switzerland); Henrich, B. [Paul Scherrer Institut, 5232 Villigen PSI (Switzerland); Hansen, K. [MAX-lab, Lund University, Lund (Sweden); O' Keefe, G.J. [Centre for PET, Austin Hospital, Heidelberg, Victoria 3084 (Australia); School of Physics, University of Melbourne, Parkville 3010 (Australia); Taylor, G.N. [School of Physics, University of Melbourne, Parkville 3010 (Australia); Boland, M.J. [Australian Synchrotron, Clayton, Victoria 3168 (Australia); School of Physics, University of Melbourne, Parkville 3010 (Australia); Thompson, M.N.; Rassool, R.P. [School of Physics, University of Melbourne, Parkville 3010 (Australia)

2009-05-21

In photonuclear experiments precise location of the photon beam relative to the experimental sample is critical. Previously used techniques such as using photographic film to identify the position, intensity and centroid of the beam is time-consuming and a faster method is required. PILATUS is a single-photon-counting pixel detector developed at the Paul Scherrer Institute (PSI), Switzerland. It is a silicon-based, two-dimensional detector with a large dynamic range and zero readout noise. Designed as an X-ray detector, its optimal quantum efficiency is between 3 and 30 keV. This paper reports measurements carried out at the MAX-lab tagged photon facility in Lund, Sweden. The beam endpoint energy of approximately 200 MeV is far above the designed optimal energy detection range of PILATUS, and provides a critical test of the use of PILATUS under high energy conditions. The detector was placed in the photon beam and images were taken both downstream of other experiments, and in close range of a 19 mm collimator. The successful measurements demonstrate the versatility and robustness of the detector and provide an effective way of quickly and accurately monitoring beam position and profile in real time.

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.

Laser cooled ion beams and strongly coupled plasmas for precision experiments

International Nuclear Information System (INIS)

Bussmann, Michael

2008-01-01

This cumulative thesis summarizes experimental and theoretical results on cooling of ion beams using single-frequency, single-mode tabletop laser systems. It consists of two parts. One deals with experiments on laser-cooling of ion beams at relativistic energies, the other with simulations of stopping and sympathetic cooling of ions for precision in-trap experiments. In the first part, experimental results are presented on laser-cooling of relativistic C 3+ ion beams at a beam energy of 122 MeV/u, performed at the Experimental Storage Ring (ESR) at GSI. The main results presented in this thesis include the first attainment of longitudinally space-charge dominated relativistic ion beams using pure laser-cooling. The second part lists theoretical results on stopping and sympathetic cooling of ions in a laser-cooled one-component plasma of singly charged 24 Mg ions, which are confined in a three-dimensional harmonic trap potential. (orig.)

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

High-precision ground-based photometry of exoplanets

Directory of Open Access Journals (Sweden)

de Mooij Ernst J.W.

2013-04-01

Full Text Available High-precision photometry of transiting exoplanet systems has contributed significantly to our understanding of the properties of their atmospheres. The best targets are the bright exoplanet systems, for which the high number of photons allow very high signal-to-noise ratios. Most of the current instruments are not optimised for these high-precision measurements, either they have a large read-out overhead to reduce the readnoise and/or their field-of-view is limited, preventing simultaneous observations of both the target and a reference star. Recently we have proposed a new wide-field imager for the Observatoir de Mont-Megantic optimised for these bright systems (PI: Jayawardhana. The instruments has a dual beam design and a field-of-view of 17' by 17'. The cameras have a read-out time of 2 seconds, significantly reducing read-out overheads. Over the past years we have obtained significant experience with how to reach the high precision required for the characterisation of exoplanet atmospheres. Based on our experience we provide the following advice: Get the best calibrations possible. In the case of bad weather, characterise the instrument (e.g. non-linearity, dome flats, bias level, this is vital for better understanding of the science data. Observe the target for as long as possible, the out-of-transit baseline is as important as the transit/eclipse itself. A short baseline can lead to improperly corrected systematic and mis-estimation of the red-noise. Keep everything (e.g. position on detector, exposure time as stable as possible. Take care that the defocus is not too strong. For a large defocus, the contribution of the total flux from the sky-background in the aperture could well exceed that of the target, resulting in very strict requirements on the precision at which the background is measured.

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)

Development of a Laser-based Emittance Monitor for Negative Hydrogen Beams

CERN Document Server

AUTHOR|(CDS)2078368; Schmauss, Bernhard; Gibson, Stephen; Boorman, Gary; Bosco, Alessio

High energy particle accelerators are designed to collide charged particle beams and thus study the collision products. Maximising the collision rate, to generate sufficient statistics for precise measurements of rare processes, is one of the key parameters for optimising the overall collider performance. The CERN Large Hadron Collider (LHC) Injectors Upgrade (LIU) includes the construction of LINAC4, a completely new machine working as a first linear acceleration stage for the LHC beam. By accelerating a negative hydrogen beam (H-) instead of protons, it aims to double the beam brightness via a more efficient transfer to the first circular accelerator and subsequently boost the LHC collision rate. To achieve this, a precise knowledge of the transverse beam characteristics in terms of beam emittance is essential. This thesis work covers the development of a laser-based monitor meant to measure non-destructively the LINAC4 beam transverse profile and emittance. This included the implementation of dif...

Influence of material removal programming on ion beam figuring of high-precision optical surfaces

Science.gov (United States)

Liao, Wenlin; Dai, Yifan; Xie, Xuhui

2014-09-01

Ion beam figuring (IBF) provides a nanometer/subnanometer precision fabrication technology for optical components, where the surface materials on highlands are gradually removed by the physical sputtering effect. In this deterministic method, the figuring process is usually divided into several iterations and the sum of the removed material in each iteration is expected to approach the ideally removed material as nearly as possible. However, we find that the material removal programming in each iteration would influence the surface error convergence of the figuring process. The influence of material removal programming on the surface error evolution is investigated through the comparative study of the contour removal method (CRM) and the geometric proportion removal method (PRM). The research results indicate that the PRM can maintenance the smoothness of the surface topography during the whole figuring process, which would benefit the stable operation of the machine tool and avoid the production of mid-to-high spatial frequency surface errors. Additionally, the CRM only has the corrective effect on the area above the contour line in each iteration, which would result in the nonuniform convergence of the surface errors in various areas. All these advantages distinguish PRM as an appropriate material removal method for ultraprecision optical surfaces.

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

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)

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.

Laser cooled ion beams and strongly coupled plasmas for precision experiments

Energy Technology Data Exchange (ETDEWEB)

Bussmann, Michael

2008-03-17

This cumulative thesis summarizes experimental and theoretical results on cooling of ion beams using single-frequency, single-mode tabletop laser systems. It consists of two parts. One deals with experiments on laser-cooling of ion beams at relativistic energies, the other with simulations of stopping and sympathetic cooling of ions for precision in-trap experiments. In the first part, experimental results are presented on laser-cooling of relativistic C{sup 3+} ion beams at a beam energy of 122 MeV/u, performed at the Experimental Storage Ring (ESR) at GSI. The main results presented in this thesis include the first attainment of longitudinally space-charge dominated relativistic ion beams using pure laser-cooling. The second part lists theoretical results on stopping and sympathetic cooling of ions in a laser-cooled one-component plasma of singly charged {sup 24}Mg ions, which are confined in a three-dimensional harmonic trap potential. (orig.)

Acoustic grating fringe projector for high-speed and high-precision three-dimensional shape measurements

International Nuclear Information System (INIS)

Yin Xuebing; Zhao Huijie; Zeng Junyu; Qu Yufu

2007-01-01

A new acoustic grating fringe projector (AGFP) was developed for high-speed and high-precision 3D measurement. A new acoustic grating fringe projection theory is also proposed to describe the optical system. The AGFP instrument can adjust the spatial phase and period of fringes with unprecedented speed and accuracy. Using rf power proportional-integral-derivative (PID) control and CCD synchronous control, we obtain fringes with fine sinusoidal characteristics and realize high-speed acquisition of image data. Using the device, we obtained a precise phase map for a 3D profile. In addition, the AGFP can work in running fringe mode, which could be applied in other measurement fields

Precision gravity measurement utilizing Accelerex vibrating beam accelerometer technology

Science.gov (United States)

Norling, Brian L.

Tests run using Sundstrand vibrating beam accelerometers to sense microgravity are described. Lunar-solar tidal effects were used as a highly predictable signal which varies by approximately 200 billionths of the full-scale gravitation level. Test runs of 48-h duration were used to evaluate stability, resolution, and noise. Test results on the Accelerex accelerometer show accuracies suitable for precision applications such as gravity mapping and gravity density logging. The test results indicate that Accelerex technology, even with an instrument design and signal processing approach not optimized for microgravity measurement, can achieve 48-nano-g (1 sigma) or better accuracy over a 48-h period. This value includes contributions from instrument noise and random walk, combined bias and scale factor drift, and thermal modeling errors as well as external contributions from sampling noise, test equipment inaccuracies, electrical noise, and cultural noise induced acceleration.

Study and realization of a beam analyser of high intensity (10610)

International Nuclear Information System (INIS)

Perret-Gallix, D.

1975-01-01

A beam analyser working under high-beam intensity in the range of 10 6 to 10 10 particles per burst and giving position profile and intensity of this beam is studied. The reasons of this study, the principle of measurement, the construction of hardware and the different tests carried out on the chamber in order to evaluate the main features are related. The analyser is a multi-cellular ionisation chamber or stripe chamber; each cell made by a copper stripe (0.25mm wide) inserted between two high voltage planes (500V) forms a small independent ionisation chamber. This system, working under the on-line control of a mini-computer allows to associate to each event or event group the instantaneous position and profile of the beam [fr

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...

Measurement of secondary particle production induced by particle therapy ion beams impinging on a PMMA target

Directory of Open Access Journals (Sweden)

Toppi M.

2016-01-01

Full Text Available Particle therapy is a technique that uses accelerated charged ions for cancer treatment and combines a high irradiation precision with a high biological effectiveness in killing tumor cells [1]. Informations about the secondary particles emitted in the interaction of an ion beam with the patient during a treatment can be of great interest in order to monitor the dose deposition. For this purpose an experiment at the HIT (Heidelberg Ion-Beam Therapy Center beam facility has been performed in order to measure fluxes and emission profiles of secondary particles produced in the interaction of therapeutic beams with a PMMA target. In this contribution some preliminary results about the emission profiles and the energy spectra of the detected secondaries will be presented.

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

Laser beam complex amplitude measurement by phase diversity.

Science.gov (United States)

Védrenne, Nicolas; Mugnier, Laurent M; Michau, Vincent; Velluet, Marie-Thérèse; Bierent, Rudolph

2014-02-24

The control of the optical quality of a laser beam requires a complex amplitude measurement able to deal with strong modulus variations and potentially highly perturbed wavefronts. The method proposed here consists in an extension of phase diversity to complex amplitude measurements that is effective for highly perturbed beams. Named camelot for Complex Amplitude MEasurement by a Likelihood Optimization Tool, it relies on the acquisition and processing of few images of the beam section taken along the optical path. The complex amplitude of the beam is retrieved from the images by the minimization of a Maximum a Posteriori error metric between the images and a model of the beam propagation. The analytical formalism of the method and its experimental validation are presented. The modulus of the beam is compared to a measurement of the beam profile, the phase of the beam is compared to a conventional phase diversity estimate. The precision of the experimental measurements is investigated by numerical simulations.

New methods for precision Moeller polarimetry*

International Nuclear Information System (INIS)

Gaskell, D.; Meekins, D.G.; Yan, C.

2007-01-01

Precision electron beam polarimetry is becoming increasingly important as parity violation experiments attempt to probe the frontiers of the standard model. In the few GeV regime, Moeller polarimetry is well suited to high-precision measurements, however is generally limited to use at relatively low beam currents (<10 μA). We present a novel technique that will enable precision Moeller polarimetry at very large currents, up to 100 μA. (orig.)

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)

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.

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

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

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)

Visualisation of the high-current e-beams on solid surfaces

Energy Technology Data Exchange (ETDEWEB)

Solomonov, V I; Osipov, V V; Mikhajlov, S G; Lipchak, A I [Russian Academy of Sciences, Ural Division, Ekaterinburg (Russian Federation). Institute of Electrophysics

1997-12-31

Natural minerals such as spodumen, calcite, and Mn-doped apatite crystals may serve as suitable low-cost materials for visualization of high-current electron beams. High-intensity luminescence lasting several tens of minutes has been observed when irradiating natural specimen by electron beams with the current density of 10-1000 A/sq.cm, with energy of 100-300 keV, and pulse duration of 2-50 ns. The luminescent images of the beam cross-section provide information on the beam density profiles, while the images taken in the plane parallel to the beam axis make it possible to estimate the beam penetration depth and, therefore, the beam energy. The method is illustrated by examples of luminescent images taken from the experiment. (J.U.).

A scintillating fibre-based profiler for low intensity ion beams

Energy Technology Data Exchange (ETDEWEB)

Finocchiaro, P. [Istituto Nazionale di Fisica Nucleare, Catania (Italy); Amato, A. [Istituto Nazionale di Fisica Nucleare, Catania (Italy); Ciavola, G. [Istituto Nazionale di Fisica Nucleare, Catania (Italy); Cuttone, G. [Istituto Nazionale di Fisica Nucleare, Catania (Italy); Gu, M. [Istituto Nazionale di Fisica Nucleare, Catania (Italy); Raia, G. [Istituto Nazionale di Fisica Nucleare, Catania (Italy); Rovelli, A. [Istituto Nazionale di Fisica Nucleare, Catania (Italy)

1997-01-11

In the framework of the EXCYT radioactive ion beam facility, now under development at LNS Catania, we have developed a new beam profile monitor based on a scintillating fibre and a photodetector. Its sensitivity allows the detection of single beam particles in pulse mode, thus representing a useful tool for diagnostics of low and very low intensity beams. (orig.).

A scintillating fibre-based profiler for low intensity ion beams

International Nuclear Information System (INIS)

Finocchiaro, P.; Amato, A.; Ciavola, G.; Cuttone, G.; Gu, M.; Raia, G.; Rovelli, A.

1997-01-01

In the framework of the EXCYT radioactive ion beam facility, now under development at LNS Catania, we have developed a new beam profile monitor based on a scintillating fibre and a photodetector. Its sensitivity allows the detection of single beam particles in pulse mode, thus representing a useful tool for diagnostics of low and very low intensity beams. (orig.)

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.

Profile Monitors Based on Residual Gas Interaction

CERN Document Server

Forck, P; Giacomini, T; Peters, A

2005-01-01

The precise determination of transverse beam profiles at high current hadron accelerators has to be performed non-interceptingly. Two methods will be discussed based on the excitation of the residual gas molecules by the beam particles: Firstly, by beam induced fluorescence (BIF) light is emitted from the residual gas molecules and is observed with an image intensified CCD camera. At most laboratories N2 gas is inserted, which has a large cross section for emission in the blue wave length region. Secondly, a larger signal strength is achieved by detecting the ionization products in an Ionization Profile Monitor (IPM). By applying an electric field all ionization products are accelerated toward a spatial resolving Micro-Channel Plate. The signal read-out can either be performed by observing the light from a phosphor screen behind the MCP or electronically by a wire array. Methods to achieve a high spatial resolution and a fast turn-by-turn readout capability are discussed. Even though various approaches at dif...

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)

A precise Higgs mass measurement at the ILC and test beam data analyses with CALICE

International Nuclear Information System (INIS)

Ruan, Manqi

2008-01-01

Utilizing Monte Carlo tools and test-beam data, some basic detector performance properties are studied for the International Linear Collider (ILC). The contributions of this thesis are mainly twofold, first, a study of the Higgs mass and cross section measurements at the ILC (with full simulation to the e + e - → HZ→Hμμ channel and backgrounds); and second, an analysis of test-beam data of the Calorimeter for Linear Collider Experiment (CALICE). For a most general type of Higgs particle with 120 GeV the mass, setting the center-of-mass energy to 230 GeV and with an integrated luminosity of 500fb -1 , a precision of 38.4 MeV is obtained in a model independent analysis for the Higgs boson mass measurement, while the cross section could be measured to 5%; if we make some assumptions about the Higgs boson's decay, for example a Standard Model Higgs boson with a dominant invisible decay mode, the measurement result can be improved by 25% (achieving a mass measurement precision of 29 MeV and a cross section measurement precision of 4%). For the CALICE test-beam data analysis, our work is mainly focused upon two aspects: data quality checks and the track-free ECAL angular measurement. Data quality checks aim to detect strange signals or unexpected phenomena in the test-beam data so that one knows quickly how the overall data taking quality is. They also serve to classify all the data and give useful information for the later offline data analyses. The track-free ECAL angular resolution algorithm is designed to precisely measure the direction of a photon, a very important component in determining the direction of the neutral components in jets. We found that the angular resolution can be well fitted as a function of the square root of the beam energy (in a similar way as for the energy resolution) with a precision of approximately 80 mrad/√(E/GeV) in the angular resolution. (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.

High-quality laser-accelerated ion beams for medical applications

Energy Technology Data Exchange (ETDEWEB)

Harman, Zoltan; Keitel, Christoph H. [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); Salamin, Yousef I. [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); American University of Sharjah (United Arab Emirates)

2009-07-01

Cancer radiation therapy requires accelerated ion beams of high energy sharpness and a narrow spatial profile. As shown recently, linearly and radially polarized, tightly focused and thus extremely strong laser beams should permit the direct acceleration of light atomic nuclei up to energies that may offer the potentiality for medical applications. Radially polarized beams have better emittance than their linearly polarized counterparts. We put forward the direct laser acceleration of ions, once the refocusing of ion beams by external fields is solved or radially polarized laser pulses of sufficient power can be generated.

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

BEAMGAA. A chance for high precision analysis of big samples

International Nuclear Information System (INIS)

Goerner, W.; Berger, A.; Haase, O.; Segebade, Chr.; Alber, D.; Monse, G.

2005-01-01

In activation analysis of traces in small samples, the non-equivalence of the activating radiation doses of sample and calibration material gives rise to sometimes tolerable systematic errors. Conversely, analysis of major components usually demands high trueness and precision. To meet this, beam geometry activation analysis (BEAMGAA) procedures have been developed for instrumental photon (IPAA) and neutron activation analysis (INAA) in which the activating neutron/photon beam exhibits broad, flat-topped characteristics. This results in a very low lateral activating flux gradient compared to known radiation facilities, however, at significantly lower flux density. The axial flux gradient can be accounted for by a monitor-sample-monitor assembly. As a first approach, major components were determined in high purity substances as well as selenium in a cattle fodder additive. (author)

Untangling the contributions of image charge and laser profile for optimal photoemission of high-brightness electron beams

International Nuclear Information System (INIS)

Portman, J.; Zhang, H.; Makino, K.; Ruan, C. Y.; Berz, M.; Duxbury, P. M.

2014-01-01

Using our model for the simulation of photoemission of high brightness electron beams, we investigate the virtual cathode physics and the limits to spatio-temporal and spectroscopic resolution originating from the image charge on the surface and from the profile of the exciting laser pulse. By contrasting the effect of varying surface properties (leading to expanding or pinned image charge), laser profiles (Gaussian, uniform, and elliptical), and aspect ratios (pancake- and cigar-like) under different extraction field strengths and numbers of generated electrons, we quantify the effect of these experimental parameters on macroscopic pulse properties such as emittance, brightness (4D and 6D), coherence length, and energy spread. Based on our results, we outline optimal conditions of pulse generation for ultrafast electron microscope systems that take into account constraints on the number of generated electrons and on the required time resolution.

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)

High Precision Edge Detection Algorithm for Mechanical Parts

Science.gov (United States)

Duan, Zhenyun; Wang, Ning; Fu, Jingshun; Zhao, Wenhui; Duan, Boqiang; Zhao, Jungui

2018-04-01

High precision and high efficiency measurement is becoming an imperative requirement for a lot of mechanical parts. So in this study, a subpixel-level edge detection algorithm based on the Gaussian integral model is proposed. For this purpose, the step edge normal section line Gaussian integral model of the backlight image is constructed, combined with the point spread function and the single step model. Then gray value of discrete points on the normal section line of pixel edge is calculated by surface interpolation, and the coordinate as well as gray information affected by noise is fitted in accordance with the Gaussian integral model. Therefore, a precise location of a subpixel edge was determined by searching the mean point. Finally, a gear tooth was measured by M&M3525 gear measurement center to verify the proposed algorithm. The theoretical analysis and experimental results show that the local edge fluctuation is reduced effectively by the proposed method in comparison with the existing subpixel edge detection algorithms. The subpixel edge location accuracy and computation speed are improved. And the maximum error of gear tooth profile total deviation is 1.9 μm compared with measurement result with gear measurement center. It indicates that the method has high reliability to meet the requirement of high precision measurement.

Precision synchrotron radiation detectors

International Nuclear Information System (INIS)

Levi, M.; Rouse, F.; Butler, J.

1989-03-01

Precision detectors to measure synchrotron radiation beam positions have been designed and installed as part of beam energy spectrometers at the Stanford Linear Collider (SLC). The distance between pairs of synchrotron radiation beams is measured absolutely to better than 28 /mu/m on a pulse-to-pulse basis. This contributes less than 5 MeV to the error in the measurement of SLC beam energies (approximately 50 GeV). A system of high-resolution video cameras viewing precisely-aligned fiducial wire arrays overlaying phosphorescent screens has achieved this accuracy. Also, detectors of synchrotron radiation using the charge developed by the ejection of Compton-recoil electrons from an array of fine wires are being developed. 4 refs., 5 figs., 1 tab

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

Fiscal 1998 research report. Application technology of next-generation high-density energy beams; 1998 nendo chosa hokokusho. Jisedai komitsudo energy beam riyo gijutsu

Energy Technology Data Exchange (ETDEWEB)

NONE

1999-03-01

Survey was made on application technologies of next- generation high-density energy beams. For real application of laser power, application to not exciting source of YAG crystal but machining directly is highly efficient. For generation of semiconductor laser high-power coherent beam, phase synchronization and summing are large technological walls. Short pulse, high intensity and high repeatability are also important. Since ultra-short pulse laser ends before heat transfer to the periphery, it is suitable for precise machining, in particular, ultra-fine machining. To use beam sources as tool for production process, development of transmission, focusing and control technologies, and optical fiber and device is indispensable. Applicable fields are as follows: machining (more than pico seconds), surface modification (modification and functionalization of tribo- materials and biocompatible materials), complex machining, fabrication of quantum functional structured materials (thin film, ultra-fine particle), agriculture, ultra-precise measurement, non-destructive measurement, and coherent chemistry in chemical and environment fields. (NEDO)

High current density ion beam obtained by a transition to a highly focused state in extremely low-energy region

Energy Technology Data Exchange (ETDEWEB)

Hirano, Y., E-mail: y.hirano@aist.go.jp, E-mail: hirano.yoichi@phys.cst.nihon-u.ac.jp [Innovative Plasma Processing Group, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8568 (Japan); College of Science and Technologies, Nihon University, Chiyodaku, Tokyo 101-0897 (Japan); Kiyama, S.; Koguchi, H. [Innovative Plasma Processing Group, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8568 (Japan); Fujiwara, Y.; Sakakita, H. [Innovative Plasma Processing Group, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8568 (Japan); Department of Engineering Mechanics and Energy, University of Tsukuba, Ibaraki 305-8577 (Japan)

2015-11-15

A high current density (≈3 mA/cm{sup 2}) hydrogen ion beam source operating in an extremely low-energy region (E{sub ib} ≈ 150–200 eV) has been realized by using a transition to a highly focused state, where the beam is extracted from the ion source chamber through three concave electrodes with nominal focal lengths of ≈350 mm. The transition occurs when the beam energy exceeds a threshold value between 145 and 170 eV. Low-level hysteresis is observed in the transition when E{sub ib} is being reduced. The radial profiles of the ion beam current density and the low temperature ion current density can be obtained separately using a Faraday cup with a grid in front. The measured profiles confirm that more than a half of the extracted beam ions reaches the target plate with a good focusing profile with a full width at half maximum of ≈3 cm. Estimation of the particle balances in beam ions, the slow ions, and the electrons indicates the possibility that the secondary electron emission from the target plate and electron impact ionization of hydrogen may play roles as particle sources in this extremely low-energy beam after the compensation of beam ion space charge.

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.

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.

A High Precision Laser-Based Autofocus Method Using Biased Image Plane for Microscopy

Directory of Open Access Journals (Sweden)

Chao-Chen Gu

2018-01-01

Full Text Available This study designs and accomplishes a high precision and robust laser-based autofocusing system, in which a biased image plane is applied. In accordance to the designed optics, a cluster-based circle fitting algorithm is proposed to calculate the radius of the detecting spot from the reflected laser beam as an essential factor to obtain the defocus value. The experiment conduct on the experiment device achieved novel performance of high precision and robustness. Furthermore, the low demand of assembly accuracy makes the proposed method a low-cost and realizable solution for autofocusing technique.

Superharp: A wire scanner with absolute position readout for beam energy measurement at CEBAF

International Nuclear Information System (INIS)

Yan, C.

1994-01-01

Superharp is an upgrade CEBAF wire scanner with absolute position readout from shaft encoder. As high precision absolute beam position probe (Δx ∼ 10μm), three pairs of superharps are installed at the entrance, the mid-point, and the exit of Hall C arc beamline in beam switch yard, which will be tuned in dispersive mode as energy spectrometer performing 10 -3 beam energy measurement. With dual sensor system: the direct current pickup and the bremsstrahlung detection electronics, beam profile can be obtained by superharp at wide beam current range from 1 μA to 100 μA

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

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

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...

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

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.

Hardron production and neutrino beams

Science.gov (United States)

Guglielmi, A.

2006-11-01

The precise measurements of the neutrino mixing parameters in the oscillation experiments at accelerators require new high-intensity and high-purity neutrino beams. Ancillary hadron-production measurements are then needed as inputs to precise calculation of neutrino beams and of atmospheric neutrino fluxes.

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.

Treatment Algorithms Based on Tumor Molecular Profiling: The Essence of Precision Medicine Trials.

Science.gov (United States)

Le Tourneau, Christophe; Kamal, Maud; Tsimberidou, Apostolia-Maria; Bedard, Philippe; Pierron, Gaëlle; Callens, Céline; Rouleau, Etienne; Vincent-Salomon, Anne; Servant, Nicolas; Alt, Marie; Rouzier, Roman; Paoletti, Xavier; Delattre, Olivier; Bièche, Ivan

2016-04-01

With the advent of high-throughput molecular technologies, several precision medicine (PM) studies are currently ongoing that include molecular screening programs and PM clinical trials. Molecular profiling programs establish the molecular profile of patients' tumors with the aim to guide therapy based on identified molecular alterations. The aim of prospective PM clinical trials is to assess the clinical utility of tumor molecular profiling and to determine whether treatment selection based on molecular alterations produces superior outcomes compared with unselected treatment. These trials use treatment algorithms to assign patients to specific targeted therapies based on tumor molecular alterations. These algorithms should be governed by fixed rules to ensure standardization and reproducibility. Here, we summarize key molecular, biological, and technical criteria that, in our view, should be addressed when establishing treatment algorithms based on tumor molecular profiling for PM trials. © The Author 2015. Published by Oxford University Press.

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. ).

High Precision Edge Detection Algorithm for Mechanical Parts

Directory of Open Access Journals (Sweden)

Duan Zhenyun

2018-04-01

Full Text Available High precision and high efficiency measurement is becoming an imperative requirement for a lot of mechanical parts. So in this study, a subpixel-level edge detection algorithm based on the Gaussian integral model is proposed. For this purpose, the step edge normal section line Gaussian integral model of the backlight image is constructed, combined with the point spread function and the single step model. Then gray value of discrete points on the normal section line of pixel edge is calculated by surface interpolation, and the coordinate as well as gray information affected by noise is fitted in accordance with the Gaussian integral model. Therefore, a precise location of a subpixel edge was determined by searching the mean point. Finally, a gear tooth was measured by M&M3525 gear measurement center to verify the proposed algorithm. The theoretical analysis and experimental results show that the local edge fluctuation is reduced effectively by the proposed method in comparison with the existing subpixel edge detection algorithms. The subpixel edge location accuracy and computation speed are improved. And the maximum error of gear tooth profile total deviation is 1.9 μm compared with measurement result with gear measurement center. It indicates that the method has high reliability to meet the requirement of high precision measurement.

Highly efficient electron vortex beams generated by nanofabricated phase holograms

Energy Technology Data Exchange (ETDEWEB)

Grillo, Vincenzo, E-mail: vincenzo.grillo@nano.cnr.it [CNR-Istituto Nanoscienze, Centro S3, Via G Campi 213/a, I-41125 Modena (Italy); CNR-IMEM Parco Area delle Scienze 37/A, I-43124 Parma (Italy); Carlo Gazzadi, Gian [CNR-Istituto Nanoscienze, Centro S3, Via G Campi 213/a, I-41125 Modena (Italy); Karimi, Ebrahim [CNR-Istituto Nanoscienze, Centro S3, Via G Campi 213/a, I-41125 Modena (Italy); Department of Physics, University of Ottawa, 150 Louis Pasteur, Ottawa, Ontario K1N 6N5 (Canada); Mafakheri, Erfan [Dipartimento di Fisica Informatica e Matematica, Università di Modena e Reggio Emilia, via G Campi 213/a, I-41125 Modena (Italy); Boyd, Robert W. [Department of Physics, University of Ottawa, 150 Louis Pasteur, Ottawa, Ontario K1N 6N5 (Canada); Frabboni, Stefano [CNR-Istituto Nanoscienze, Centro S3, Via G Campi 213/a, I-41125 Modena (Italy); Dipartimento di Fisica Informatica e Matematica, Università di Modena e Reggio Emilia, via G Campi 213/a, I-41125 Modena (Italy)

2014-01-27

We propose an improved type of holographic-plate suitable for the shaping of electron beams. The plate is fabricated by a focused ion beam on a silicon nitride membrane and introduces a controllable phase shift to the electron wavefunction. We adopted the optimal blazed-profile design for the phase hologram, which results in the generation of highly efficient (25%) electron vortex beams. This approach paves the route towards applications in nano-scale imaging and materials science.

Highly efficient electron vortex beams generated by nanofabricated phase holograms

International Nuclear Information System (INIS)

Grillo, Vincenzo; Carlo Gazzadi, Gian; Karimi, Ebrahim; Mafakheri, Erfan; Boyd, Robert W.; Frabboni, Stefano

2014-01-01

We propose an improved type of holographic-plate suitable for the shaping of electron beams. The plate is fabricated by a focused ion beam on a silicon nitride membrane and introduces a controllable phase shift to the electron wavefunction. We adopted the optimal blazed-profile design for the phase hologram, which results in the generation of highly efficient (25%) electron vortex beams. This approach paves the route towards applications in nano-scale imaging and materials science

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

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

Commissioning of a medical accelerator photon beam Monte Carlo simulation using wide-field profiles

International Nuclear Information System (INIS)

Pena, J; Franco, L; Gomez, F; Iglesias, A; Lobato, R; Mosquera, J; Pazos, A; Pardo, J; Pombar, M; RodrIguez, A; Sendon, J

2004-01-01

A method for commissioning an EGSnrc Monte Carlo simulation of medical linac photon beams through wide-field lateral profiles at moderate depth in a water phantom is presented. Although depth-dose profiles are commonly used for nominal energy determination, our study shows that they are quite insensitive to energy changes below 0.3 MeV (0.6 MeV) for a 6 MV (15 MV) photon beam. Also, the depth-dose profile dependence on beam radius adds an additional uncertainty in their use for tuning nominal energy. Simulated 40 cm x 40 cm lateral profiles at 5 cm depth in a water phantom show greater sensitivity to both nominal energy and radius. Beam parameters could be determined by comparing only these curves with measured data

Commissioning of a medical accelerator photon beam Monte Carlo simulation using wide-field profiles

Energy Technology Data Exchange (ETDEWEB)

Pena, J [Departamento de Fisica de PartIculas, Facultade de Fisica, 15782 Santiago de Compostela (Spain); Franco, L [Departamento de Fisica de PartIculas, Facultade de Fisica, 15782 Santiago de Compostela (Spain); Gomez, F [Departamento de Fisica de PartIculas, Facultade de Fisica, 15782 Santiago de Compostela (Spain); Iglesias, A [Departamento de Fisica de PartIculas, Facultade de Fisica, 15782 Santiago de Compostela (Spain); Lobato, R [Hospital ClInico Universitario de Santiago, Santiago de Compostela (Spain); Mosquera, J [Hospital ClInico Universitario de Santiago, Santiago de Compostela (Spain); Pazos, A [Departamento de Fisica de PartIculas, Facultade de Fisica, 15782 Santiago de Compostela (Spain); Pardo, J [Departamento de Fisica de PartIculas, Facultade de Fisica, 15782 Santiago de Compostela (Spain); Pombar, M [Hospital ClInico Universitario de Santiago, Santiago de Compostela (Spain); RodrIguez, A [Departamento de Fisica de PartIculas, Facultade de Fisica, 15782 Santiago de Compostela (Spain); Sendon, J [Hospital ClInico Universitario de Santiago, Santiago de Compostela (Spain)

2004-11-07

A method for commissioning an EGSnrc Monte Carlo simulation of medical linac photon beams through wide-field lateral profiles at moderate depth in a water phantom is presented. Although depth-dose profiles are commonly used for nominal energy determination, our study shows that they are quite insensitive to energy changes below 0.3 MeV (0.6 MeV) for a 6 MV (15 MV) photon beam. Also, the depth-dose profile dependence on beam radius adds an additional uncertainty in their use for tuning nominal energy. Simulated 40 cm x 40 cm lateral profiles at 5 cm depth in a water phantom show greater sensitivity to both nominal energy and radius. Beam parameters could be determined by comparing only these curves with measured data.

Formation of a high quality electron beam using photo cathode RF electron gun

International Nuclear Information System (INIS)

Washio, Masakazu

2000-01-01

Formation of a high quality electron beam using photo cathode RF electron gun is expected for formation of a next generation high brilliant X-ray beam and a source for electron and positron collider. And, on a field of material science, as is possible to carry out an experiment under ultra short pulse and extremely high precision in time, it collects large expectation. Recently, formation of high quality beam possible to develop for multi directions and to use by everyone in future has been able to realize. Here were explained on electron beam source, principle and component on RF electron gun, working features on RF gun, features and simulation of RF gun under operation, and some views in near future. (G.K.)

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.

Wideband Precision Current Transformer for the Magnet Current of the Beam Extraction Kicker Magnet of the Large Hadron Collider

CERN Document Server

Gräwer, G

2004-01-01

The LHC beam extraction system is composed of 15 fast kicker magnets per beam to extract the particles in one turn of the collider and to safely dispose them on external absorbers. Each magnet is powered by a separate pulse generator. The generator produces a magnet current pulse with 3 us rise time, 20 kA amplitude and 1.8 ms fall time, of which 90 us are needed to dump the beam. The beam extraction system requires a high level of reliability. To detect any change in the magnet current characteristics, which might indicate a slow degradation of the pulse generator, a high precision wideband current transformer will be installed. For redundancy reasons, the results obtained with this device will be cross-checked with a Rogowski coil, installed adjacent to the transformer. A prototype transformer has been successfully tested at nominal current levels and showed satisfactory results compared with the output of a high frequency resistive coaxial shunt. The annular core of the ring type transformer is composed of...

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

Interferometric Star Tracker for High Precision Pointing, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — Optical Physics Company (OPC) proposes to adapt the precision star tracker it is currently developing under several DoD contracts for deep space lasercom beam...

Electron beam gun with kinematic coupling for high power RF vacuum devices

Science.gov (United States)

Borchard, Philipp

2016-11-22

An electron beam gun for a high power RF vacuum device has components joined by a fixed kinematic coupling to provide both precise alignment and high voltage electrical insulation of the components. The kinematic coupling has high strength ceramic elements directly bonded to one or more non-ductile rigid metal components using a high temperature active metal brazing alloy. The ceramic elements have a convex surface that mates with concave grooves in another one of the components. The kinematic coupling, for example, may join a cathode assembly and/or a beam shaping focus electrode to a gun stem, which is preferably composed of ceramic. The electron beam gun may be part of a high power RF vacuum device such as, for example, a gyrotron, klystron, or magnetron.

Production of high energy, uniform focal profiles with the Nike laser

Science.gov (United States)

Lehecka, T.; Lehmberg, R. H.; Deniz, A. V.; Gerber, K. A.; Obenschain, S. P.; Pawley, C. J.; Pronko, M. S.; Sullivan, C. A.

1995-02-01

Nike, a KrF laser facility at the Naval Research Laboratory, is designed to produce high intensity, ultra-uniform focal profiles for experiments relating to direct drive inertial confinement fusion. We present measurements of focal profiles through the next-to-last amplifier, a 20 × 20 cm 2 aperture electron beam pumped amplifier capable of producing more than 120 J of output in a 120 ns pulse. Using echelon free induced spatial incoherence beam smoothing this system has produced focal profiles with less than 2% tilt and curvature and less than 2% rms variation from a flat top distribution.

A sweep plate emittance scanner for high-power CW ion beams

International Nuclear Information System (INIS)

Debiak, T.W.; Ng, Y.; Sredniawski, J.; Stasi, W.

1996-01-01

Sweep plate scanners are preferred for emittance measurement due to their versatility, simplicity, and precision. At the Advanced Technology and Development Center of Northrop Grumman, we have routinely used these devices for characterization of injector beams with less than 20 W/cm 2 average power density. To characterize higher power beams, like those required for production of tritium or for radioactive waste transmutation, the scanner pod and data collection algorithm must be redesigned due to the possibility of melting the scanner's protective front face or distorting the precision entrance knife edges. Among the methods we have used to mitigate these effects, one consists of drastically reducing the amount of time required for data collection. In this method, the emittance scanner pod traverses the beam in two passes, each requiring less than 0.5 second. In the first pass, the phase space limits of the beam are determined. In the second pass, data is collected primarily within the phase space region limits determined in the first pass. In this way, enough points are collected to assure that the precision of the measurement is high, even though the data collection time for each scan is less than 0.5 second. This paper will describe the layout of the scanner components, the data collection electronics and algorithm, and the data analysis. (author)

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).

Precision Beam Parameter Monitoring in a Measurement of the Weak Mixing Angle in Moeller Scattering

Energy Technology Data Exchange (ETDEWEB)

Cooke, M.S.

2005-04-11

A precision measurement of the parity nonconserving left-right asymmetry, A{sub LR}, in Moeller scattering (e{sup -}e{sup -} {yields} e{sup -}e{sup -}) is currently in progress at the Stanford Linear Accelerator Center (SLAC). This experiment, labeled SLAC-E158, scatters longitudinally polarized electrons off atomic electrons in an unpolarized hydrogen target at a Q{sup 2} of 0.03 (GeV/c){sup 2}. The asymmetry, which is the fractional difference in the scattering cross-sections, measures the effective pseudo-scalar weak neutral current coupling, g{sub ee}, governing Moeller scattering. This quantity is in turn proportional to (1/4 - sin{sup 2} {theta}{sub w}), where {theta}{sub w} is the electroweak mixing angle. The goal is to measure the asymmetry to a precision of 1 x 10{sup -8} which corresponds to {delta}(sin{sup 2} {theta}{sub w}) {approx} 0.0007. Since A{sub LR} is a function of the cross-sections, and the cross-sections depend on the beam parameters, the desired precision of A{sub LR} places stringent requirements on the beam parameters. This paper investigates the requirements on the beam parameters and discusses the means by which they are monitored and accounted for.

Chip-carrier thermal barrier and its impact on lateral thermal lens profile and beam parameter product in high power broad area lasers

Science.gov (United States)

Rieprich, J.; Winterfeldt, M.; Kernke, R.; Tomm, J. W.; Crump, P.

2018-03-01

High power broad area diode lasers with high optical power density in a small focus spot are in strong commercial demand. For this purpose, the beam quality, quantified via the beam parameter product (BPP), has to be improved. Previous studies have shown that the BPP is strongly affected by current-induced heating and the associated thermal lens formed within the laser stripe. However, the chip structure and module-assembly related factors that regulate the size and the shape of the thermal lens are not well known. An experimental infrared thermographic technique is used to quantify the thermal lens profile in diode lasers operating at an emission wavelength of 910 nm, and the results are compared with finite element method simulations. The analysis indicates that the measured thermal profiles can best be explained when a thermal barrier is introduced between the chip and the carrier, which is shown to have a substantial impact on the BPP and the thermal resistance. Comparable results are observed in further measurements of samples from multiple vendors, and the barrier is only observed for junction-down (p-down) mounting, consistent with the barrier being associated with the GaAs-metal transition.

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.

Characterization of a microDiamond detector in high-dose-per-pulse electron beams for intra operative radiation therapy.

Science.gov (United States)

Di Venanzio, C; Marinelli, Marco; Tonnetti, A; Verona-Rinati, G; Falco, M D; Pimpinella, M; Ciccotelli, A; De Stefano, S; Felici, G; Marangoni, F

2015-12-01

To characterize a synthetic diamond dosimeter (PTW Freiburg microDiamond 60019) in high dose-per-pulse electron beams produced by an Intra Operative Radiation Therapy (IORT) dedicated accelerator. The dosimetric properties of the microDiamond were assessed under 6, 8 and 9 MeV electron beams by a NOVAC11 mobile accelerator (Sordina IORT Technologies S.p.A.). The characterization was carried out with dose-per-pulse ranging from 26 to 105 mGy per pulse. The microDiamond performance was compared with an Advanced Markus ionization chamber and a PTW silicon diode E in terms of dose linearity, percentage depth dose (PDD) curves, beam profiles and output factors. A good linearity of the microDiamond response was verified in the dose range from 0.2 Gy to 28 Gy. A sensitivity of 1.29 nC/Gy was measured under IORT electron beams, resulting within 1% with respect to the one obtained in reference condition under (60)Co gamma irradiation. PDD measurements were found in agreement with the ones by the reference dosimeters, with differences in R50 values below 0.3 mm. Profile measurements evidenced a high spatial resolution of the microDiamond, slightly worse than the one of the silicon diode. The penumbra widths measured by the microDiamond resulted approximately 0.5 mm larger than the ones by the Silicon diode. Output factors measured by the microDiamond were found within 2% with those obtained by the Advanced Markus down to 3 cm diameter field sizes. The microDiamond dosimeter was demonstrated to be suitable for precise dosimetry in IORT applications under high dose-per-pulse conditions. Copyright © 2015 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

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

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

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

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.

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.

A counting silicon microstrip detector for precision compton polarimetry

CERN Document Server

Doll, D W; Hillert, W; Krüger, H; Stammschroer, K; Wermes, N

2002-01-01

A detector for the detection of laser photons backscattered off an incident high-energy electron beam for precision Compton polarimetry in the 3.5 GeV electron stretcher ring ELSA at Bonn University has been developed using individual photon counting. The photon counting detector is based on a silicon microstrip detector system using dedicated ASIC chips. The produced hits by the pair converted Compton photons are accumulated rather than individually read out. A transverse profile displacement can be measured with mu m accuracy rendering a polarization measurement of the order of 1% on the time scale of 10-15 min possible.

A low cost high resolution pattern generator for electron-beam lithography

International Nuclear Information System (INIS)

Pennelli, G.; D'Angelo, F.; Piotto, M.; Barillaro, G.; Pellegrini, B.

2003-01-01

A simple, very low cost pattern generator for electron-beam lithography is presented. When it is applied to a scanning electron microscope, the system allows a high precision positioning of the beam for lithography of very small structures. Patterns are generated by a suitable software implemented on a personal computer, by using very simple functions, allowing an easy development of new writing strategies for a great adaptability to different user necessities. Hardware solutions, as optocouplers and battery supply, have been implemented for reduction of noise and disturbs on the voltages controlling the positioning of the beam

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

High precision measurement of the {eta} meson mass at COSY-ANKE

Energy Technology Data Exchange (ETDEWEB)

Goslawski, Paul

2013-07-01

Previous measurements of the {eta} meson mass performed at different experimental facilities resulted in very precise data but differ by up to more than eight standard deviations, i.e., 0.5 MeV/c. Interestingly, the difference seems to be dependent on the measuring method: two missing mass experiments, which produce the {eta} meson in the {sup 3}He{eta} final state, deviate from the recent invariant mass ones. In order to clarify this ambiguous situation a high precision mass measurement was realised at the COSY-ANKE facility. Therefore, a set of deuteron laboratory beam momenta and their associated {sup 3}He centre-of-mass momenta was measured in the dp{yields}{sup 3}HeX reaction near the {eta} production threshold. The {eta} meson was identified by the missing mass peak, whereas its mass was extracted by fixing the production threshold. The individual beam momenta were determined with a relative precision of 3 x 10{sup -5} for values just above 3 GeV/c by using a polarised deuteron beam and inducing an artificial depolarising spin resonance occurring at a well-defined frequency. The final state momenta in the two-body reaction dp{yields}{sup 3}He{eta} were investigated in detail by studying the size of the {sup 3}He momentum sphere with the forward detection system of the ANKE spectrometer. Final alignment and momentum calibration of the spectrometer was achieved by a comprehensive study of the {sup 3}He final state momenta as a function of the centre-of-mass angles, taking advantage of the full geometrical acceptance. The value obtained for the mass at COSY-ANKE m{sub {eta}}=(547.873{+-}0.005{sub stat.}{+-}0.027{sub syst.}) MeV/c{sup 2} is therefore worldwide the most precise one. This mass value is contrary to earlier missing mass experiments but it is consistent and competitive with recent invariant mass measurements, in which the meson was detected through its decay products.

High throughput diffractive multi-beam femtosecond laser processing using a spatial light modulator

Energy Technology Data Exchange (ETDEWEB)

Kuang Zheng [Laser Group, Department of Engineering, University of Liverpool Brownlow Street, Liverpool L69 3GQ (United Kingdom)], E-mail: z.kuang@liv.ac.uk; Perrie, Walter [Laser Group, Department of Engineering, University of Liverpool Brownlow Street, Liverpool L69 3GQ (United Kingdom); Leach, Jonathan [Department of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ (United Kingdom); Sharp, Martin; Edwardson, Stuart P. [Laser Group, Department of Engineering, University of Liverpool Brownlow Street, Liverpool L69 3GQ (United Kingdom); Padgett, Miles [Department of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ (United Kingdom); Dearden, Geoff; Watkins, Ken G. [Laser Group, Department of Engineering, University of Liverpool Brownlow Street, Liverpool L69 3GQ (United Kingdom)

2008-12-30

High throughput femtosecond laser processing is demonstrated by creating multiple beams using a spatial light modulator (SLM). The diffractive multi-beam patterns are modulated in real time by computer generated holograms (CGHs), which can be calculated by appropriate algorithms. An interactive LabVIEW program is adopted to generate the relevant CGHs. Optical efficiency at this stage is shown to be {approx}50% into first order beams and real time processing has been carried out at 50 Hz refresh rate. Results obtained demonstrate high precision surface micro-structuring on silicon and Ti6Al4V with throughput gain >1 order of magnitude.

Analytical solutions for thermal transient profile in solid target irradiated with low energy and high beam current protons

International Nuclear Information System (INIS)

Oliveira, Henrique B. de; Brazao, Nei G.; Sciani, Valdir

2009-01-01

There were obtained analytical solutions for thermal transient in solid targets, used in short half-life radioisotopes production, when irradiated with low energy and high beam current protons, in the cyclotron accelerator Cyclone 30 of the Institute for Energy and Nuclear Research (IPEN/CNEN-SP). The beam spatial profile was considered constant and the time depended heat distribution equation was resolved for a continuous particles flow entering the target. The problem was divided into two stages: a general solution was proposed which is the sum of two functions, the first one related to the thermal equilibrium situation and the second one related to a time dependent function that was determinate by the setting of the contour conditions and the initial conditions imposed by the real problem. By that one got an analytic function for a complete description of the heat transport phenomenon inside the targets. There were used both, numerical and symbolic computation methods, to obtain temperature maps and thermal gradients and the results showed an excellent agreement when compared with purely numerical models. The results were compared with obtained data from Gallium-67 and Thallium-201 irradiation routines conducted by the IPEN Cyclotrons accelerators center, showing excellent agreement. The objective of this paper is to develop solid targets irradiation systems (metals and oxides) so that one can operate with high levels of current beam, minimizing the irradiation time and maximizing the final returns. (author)

Position sensitive detector used to detect beam profile

International Nuclear Information System (INIS)

Zhao Xiaoyan; Zhao Zhizheng; Zu Kailing; Zheng Jianhua; Wang Yifang

2003-01-01

In order to study the detecting system of the residual-gas beam profile, we introduce the principle and construction of the Position Sensitive Detector (PSD). The performance of PSD is tested. Position resolution, position linearity, detection efficiency and background are obtained

Collective Thomson scattering of a high power electron cyclotron resonance heating beam in LHD

DEFF Research Database (Denmark)

Kubo, S.; Nishiura, M.; Tanaka, K.

2010-01-01

Collective Thomson scattering (CTS) system has been constructed at LHD making use of the high power ECRH system in LHD. The necessary features for CTS, high power probing beams and receiving beams, both with well defined Gaussian profile and with the fine controllability, are endowed in the ECRH ...

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.

Precision laser spectroscopy of highly charged ions

International Nuclear Information System (INIS)

Kuehl, T.; Borneis, S.; Becker, S.; Dax, A.; Engel, T.; Grieser, R.; Huber, G.; Klaft, I.; Klepper, O.; Kohl, A.; Marx, D.; Meier, K.; Neumann, R.; Schmitt, F.; Seelig, P.; Voelker, L.

1996-01-01

Recently, intense beams of highly charged ions have become available at heavy ion cooler rings. The obstacle for producing these highly interesting candidates is the large binding energy of K-shell electrons in heavy systems in excess of 100 keV. One way to remove these electrons is to strip them off by passing the ion through material. In the cooler ring, the ions are cooled to a well defined velocity. At the SIS/ESR complex it is possible to produce, store, and cool highly charged ions up to bare uranium with intensities exceeding 10 8 atoms in the ring. This opens the door for precision laser spectroscopy of hydrogenlike-heavy ions, e.g. 209 Bi 82+ , and allows to examine the interaction of the single electron with the large fields of the heavy nucleus, exceeding any artificially produced electric and magnetic fields by orders of magnitude. In the electron cooler the interaction of electrons and highly charged ions otherwise only present in the hottest plasmas can be studied. (orig.)

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.

High-precision branching ratio measurement for the superallowed β+ emitter Ga62

Science.gov (United States)

Finlay, P.; Ball, G. C.; Leslie, J. R.; Svensson, C. E.; Towner, I. S.; Austin, R. A. E.; Bandyopadhyay, D.; Chaffey, A.; Chakrawarthy, R. S.; Garrett, P. E.; Grinyer, G. F.; Hackman, G.; Hyland, B.; Kanungo, R.; Leach, K. G.; Mattoon, C. M.; Morton, A. C.; Pearson, C. J.; Phillips, A. A.; Ressler, J. J.; Sarazin, F.; Savajols, H.; Schumaker, M. A.; Wong, J.

2008-08-01

A high-precision branching ratio measurement for the superallowed β+ decay of Ga62 was performed at the Isotope Separator and Accelerator (ISAC) radioactive ion beam facility. The 8π spectrometer, an array of 20 high-purity germanium detectors, was employed to detect the γ rays emitted following Gamow-Teller and nonanalog Fermi β+ decays of Ga62, and the SCEPTAR plastic scintillator array was used to detect the emitted β particles. Thirty γ rays were identified following Ga62 decay, establishing the superallowed branching ratio to be 99.858(8)%. Combined with the world-average half-life and a recent high-precision Q-value measurement for Ga62, this branching ratio yields an ft value of 3074.3±1.1 s, making Ga62 among the most precisely determined superallowed ft values. Comparison between the superallowed ft value determined in this work and the world-average corrected F tmacr value allows the large nuclear-structure-dependent correction for Ga62 decay to be experimentally determined from the CVC hypothesis to better than 7% of its own value, the most precise experimental determination for any superallowed emitter. These results provide a benchmark for the refinement of the theoretical description of isospin-symmetry breaking in A⩾62 superallowed decays.

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

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.

Multi-focus beam shaping of high power multimode lasers

Science.gov (United States)

Laskin, Alexander; Volpp, Joerg; Laskin, Vadim; Ostrun, Aleksei

2017-08-01

Beam shaping of powerful multimode fiber lasers, fiber-coupled solid-state and diode lasers is of great importance for improvements of industrial laser applications. Welding, cladding with millimetre scale working spots benefit from "inverseGauss" intensity profiles; performance of thick metal sheet cutting, deep penetration welding can be enhanced when distributing the laser energy along the optical axis as more efficient usage of laser energy, higher edge quality and reduction of the heat affected zone can be achieved. Building of beam shaping optics for multimode lasers encounters physical limitations due to the low beam spatial coherence of multimode fiber-coupled lasers resulting in big Beam Parameter Products (BPP) or M² values. The laser radiation emerging from a multimode fiber presents a mixture of wavefronts. The fiber end can be considered as a light source which optical properties are intermediate between a Lambertian source and a single mode laser beam. Imaging of the fiber end, using a collimator and a focusing objective, is a robust and widely used beam delivery approach. Beam shaping solutions are suggested in form of optics combining fiber end imaging and geometrical separation of focused spots either perpendicular to or along the optical axis. Thus, energy of high power lasers is distributed among multiple foci. In order to provide reliable operation with multi-kW lasers and avoid damages the optics are designed as refractive elements with smooth optical surfaces. The paper presents descriptions of multi-focus optics as well as examples of intensity profile measurements of beam caustics and application results.

Beam transport optics for high-power laser systems

International Nuclear Information System (INIS)

Taylor, J.R.

1995-01-01

Beam transport optics receive output energy from the laser cavity and deliver it to the work site. Depending on the application, this may require a few simple elements or large complex systems. Collection of the laser energy depends on the spatial and temporal energy distribution as well as the wavelength and polarization of the laser cavity and output coupler. Transport optics can perform a variety of functions, including beam formatting, frequency doubling, and distribution to one or more work sites while maintaining or even improving the beam quality. The beam may be delivered to work sites as focused spots or images, projected to distant targets, or propagated through various media for sensing or photochemical processing. Design may involve optical modeling of the system, including diffraction effects and thermal management. A Gaussian beam profile is often used for convenience in modeling. When deviations from this ideal profile need to be considered, it is necessary to characterize the laser beam in detail. Design of the transport system requires understanding of the interaction of the laser energy with optical materials and components. Practical considerations include mounting the optics without stress and with the stability suitable for the intended application. Requirements for beam direction, stability, size, shape, and quality dictate the design approach for each specific situation. Attention also must be given to reliability, environmental, and commercial requirements. Damage to optics in high-power laser systems is a common concern. Environmental problems such as atmospheric turbulence, contamination by dust or vapor from the work site or other sources, or absorption of water vapor can directly degrade beam quality. Other potentially significant optical performance effects may result from instability and aging of the optics, temperature, humidity, pressure, transmitted vibration, and contamination from the work site or other sources

A precision synchrotron radiation detector using phosphorescent screens

International Nuclear Information System (INIS)

Jung, C.K.; Lateur, M.; Nash, J.; Tinsman, J.; Butler, J.; Wormser, G.

1990-01-01

A precision detector to measure synchrotron radiation beam positions has been designed and installed as part of beam energy spectrometers at the Stanford Linear Collider (SLC). The distance between pairs of synchrotron radiation beams is measured absolutely to better than 28 μm on a pulse-to-pulse basis. This contributes less than 5 MeV to the error in the measurement of SLC beam energies (approximately 50 GeV). A system of high-resolution video cameras viewing precisely aligned fiducial wire arrays overlaying phosphorescent screens has achieved this accuracy. 3 refs., 5 figs., 1 tab

Detection of an electron beam in a high density plasma via an electrostatic probe

Science.gov (United States)

Majeski, Stephen; Yoo, Jongsoo; Zweben, Stewart; Yamada, Masaaki; Ji, Hantao

2017-10-01

The perturbation in floating potential by an electron beam is detected by a 1D floating potential probe array to evaluate the use of an electron beam for magnetic field line mapping in the Magnetic Reconnection Experiment (MRX) plasma. The MRX plasma is relatively high density (1013 cm-3) and low temperature (5 eV). Beam electrons are emitted from a tungsten filament and are accelerated by a 200 V potential across the sheath. They stream along the magnetic field lines towards the probe array. The spatial electron beam density profile is assumed to be a Gaussian along the radial axis of MRX and the effective beam width is determined from the radial profile of the floating potential. The magnitude of the perturbation is in agreement with theoretical predictions and the location of the perturbation is also in agreement with field line mapping. In addition, no significant broadening of the electron beam is observed after propagation for tens of centimeters through the high density plasma. These results demonstrate that this method of field line mapping is, in principle, feasible in high density plasmas. This work is supported by the DOE Contract No. DE-AC0209CH11466.

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.

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.

Mats and LaSpec: High-precision experiments using ion traps and lasers at Fair

Energy Technology Data Exchange (ETDEWEB)

Rodriguez, D.; Lallena, A.M.; Blaum, K.; Bohm, C.; Cakirli, R.B.; Crespo Lopez-Urrutia, J.R.; Eliseev, S.; Ketelaer, J.; Kreim, M.S.; Kowalska, M.; Litvinov, Y.A.; Nagy, S.; Neidherr, D.; Repp, J.; Roux, C.; Schabinger, B.; Ullrich, J.; Nortershauser, W.; Eberhardt, K.; Geppert, C.; Kramer, J.; Krieger, A.; Sanchez, R.; Ahammed, M.; Das, P.; Ray, A.; Algora, A.; Rubio, B.; Tain, J.L.; Audi, G.; Lunney, D.; Naimi, S.; Aysto, J.; Jokinen, A.; Kolhinen, V.; Moore, I.; Beck, D.; Block, M.; Geissel, H.; Heinz, S.; Herfurth, F.; Litvinov, Y.A.; Minaya-Ramirez, E.; Plab, W.R.; Quint, W.; Scheidenberger, C.; Winkler, M.; Bender, M.; Billowes, J.; Campbell, P.; Flanagan, K.T.; Schwarz, S.; Bollen, G.; Ferrer, R.; George, S.; Kester, O.; Brodeur, M.; Brunner, T.; Delheij, P.; Dilling, J.; Ettenauer, S.; Lapierre, A.; Bushaw, B.A.; Cano-Ott, D.; Martinez, T.; Cortes, G.; Gomez-Hornillos, M.B.; Dax, A.; Herlert, A.; Yordanov, D.; De, A.; Dickel, T.; Geissel, H.; Jesch, C.; Kuhl, T.; Petrick, M.; PlaB, W.R.; Scheidenberger, C.; Garcia-Ramos, J.E.; Gartzke, E.; Habs, D.; Szerypo, J.; Thirolf, P.G.; Weber, C.; Gusev, Y.; Nesterenko, D.; Novikov, Y.N.; Popov, A.; Seliverstov, M.; Vasiliev, A.; Vorobjev, G.; Heenen, P.H.; Marx, G.; Schweikhard, L.; Ziegler, F.; Hobein, M.; Schuch, R.; Solders, A.; Suhonen, M.; Huber, G.; Wendt, K.; Huyse, M.; Koudriavtsev, I.; Neyens, G.; Van Duppen, P.; Le Blanc, F.; Matos, M.; Reinhard, P.G.; Schneider, D.

2010-05-15

Nuclear ground state properties including mass, charge radii, spins and moments can be determined by applying atomic physics techniques such as Penning-trap based mass spectrometry and laser spectroscopy. The MATS and LaSpec setups at the low-energy beamline at FAIR will allow us to extend the knowledge of these properties further into the region far from stability. With MATS (Precision Measurements of very short-lived nuclei using an Advanced Trapping System for highly-charged ions) at FAIR we aim to apply several techniques to very short-lived radionuclides: High-accuracy mass measurements, in-trap conversion electron and alpha spectroscopy, and trap-assisted spectroscopy. The experimental setup of MATS is a unique combination of an electron beam ion trap for charge breeding, ion traps for beam preparation, and a high-precision Penning trap system for mass measurements and decay studies. For the mass measurements, MATS offers both a high accuracy and a high sensitivity. A relative mass uncertainty of 10{sup -9} can be reached by employing highly-charged ions and a non-destructive Fourier-Transform Ion-Cyclotron-Resonance (FT-ICR) detection technique on single stored ions. Decay studies in ion traps will become possible with MATS. Laser spectroscopy of radioactive isotopes and isomers is an efficient and model-independent approach for the determination of nuclear ground and isomeric state properties. Hyperfine structures and isotope shifts in electronic transitions exhibit readily accessible information on the nuclear spin, magnetic dipole and electric quadrupole moments as well as root-mean-square charge radii. The accuracy of laser-spectroscopic-determined nuclear properties is very high while requirements concerning production rates are moderate. This Technical Design Report describes a new Penning trap mass spectrometry setup as well as a number of complementary experimental devices for laser spectroscopy. Since MATS and LaSpec require high-quality low

Mats and LaSpec: High-precision experiments using ion traps and lasers at Fair

International Nuclear Information System (INIS)

Rodriguez, D.; Lallena, A.M.; Blaum, K.; Bohm, C.; Cakirli, R.B.; Crespo Lopez-Urrutia, J.R.; Eliseev, S.; Ketelaer, J.; Kreim, M.S.; Kowalska, M.; Litvinov, Y.A.; Nagy, S.; Neidherr, D.; Repp, J.; Roux, C.; Schabinger, B.; Ullrich, J.; Nortershauser, W.; Eberhardt, K.; Geppert, C.; Kramer, J.; Krieger, A.; Sanchez, R.; Ahammed, M.; Das, P.; Ray, A.; Algora, A.; Rubio, B.; Tain, J.L.; Audi, G.; Lunney, D.; Naimi, S.; Aysto, J.; Jokinen, A.; Kolhinen, V.; Moore, I.; Beck, D.; Block, M.; Geissel, H.; Heinz, S.; Herfurth, F.; Litvinov, Y.A.; Minaya-Ramirez, E.; Plab, W.R.; Quint, W.; Scheidenberger, C.; Winkler, M.; Bender, M.; Billowes, J.; Campbell, P.; Flanagan, K.T.; Schwarz, S.; Bollen, G.; Ferrer, R.; George, S.; Kester, O.; Brodeur, M.; Brunner, T.; Delheij, P.; Dilling, J.; Ettenauer, S.; Lapierre, A.; Bushaw, B.A.; Cano-Ott, D.; Martinez, T.; Cortes, G.; Gomez-Hornillos, M.B.; Dax, A.; Herlert, A.; Yordanov, D.; De, A.; Dickel, T.; Geissel, H.; Jesch, C.; Kuhl, T.; Petrick, M.; PlaB, W.R.; Scheidenberger, C.; Garcia-Ramos, J.E.; Gartzke, E.; Habs, D.; Szerypo, J.; Thirolf, P.G.; Weber, C.; Gusev, Y.; Nesterenko, D.; Novikov, Y.N.; Popov, A.; Seliverstov, M.; Vasiliev, A.; Vorobjev, G.; Heenen, P.H.; Marx, G.; Schweikhard, L.; Ziegler, F.; Hobein, M.; Schuch, R.; Solders, A.; Suhonen, M.; Huber, G.; Wendt, K.; Huyse, M.; Koudriavtsev, I.; Neyens, G.; Van Duppen, P.; Le Blanc, F.; Matos, M.; Reinhard, P.G.; Schneider, D.

2010-01-01

Nuclear ground state properties including mass, charge radii, spins and moments can be determined by applying atomic physics techniques such as Penning-trap based mass spectrometry and laser spectroscopy. The MATS and LaSpec setups at the low-energy beamline at FAIR will allow us to extend the knowledge of these properties further into the region far from stability. With MATS (Precision Measurements of very short-lived nuclei using an Advanced Trapping System for highly-charged ions) at FAIR we aim to apply several techniques to very short-lived radionuclides: High-accuracy mass measurements, in-trap conversion electron and alpha spectroscopy, and trap-assisted spectroscopy. The experimental setup of MATS is a unique combination of an electron beam ion trap for charge breeding, ion traps for beam preparation, and a high-precision Penning trap system for mass measurements and decay studies. For the mass measurements, MATS offers both a high accuracy and a high sensitivity. A relative mass uncertainty of 10 -9 can be reached by employing highly-charged ions and a non-destructive Fourier-Transform Ion-Cyclotron-Resonance (FT-ICR) detection technique on single stored ions. Decay studies in ion traps will become possible with MATS. Laser spectroscopy of radioactive isotopes and isomers is an efficient and model-independent approach for the determination of nuclear ground and isomeric state properties. Hyperfine structures and isotope shifts in electronic transitions exhibit readily accessible information on the nuclear spin, magnetic dipole and electric quadrupole moments as well as root-mean-square charge radii. The accuracy of laser-spectroscopic-determined nuclear properties is very high while requirements concerning production rates are moderate. This Technical Design Report describes a new Penning trap mass spectrometry setup as well as a number of complementary experimental devices for laser spectroscopy. Since MATS and LaSpec require high-quality low-energy beams

Foreign Object Detection by Sub-Terahertz Quasi-Bessel Beam Imaging

Directory of Open Access Journals (Sweden)

Hyang Sook Chun

2012-12-01

Full Text Available Food quality monitoring, particularly foreign object detection, has recently become a critical issue for the food industry. In contrast to X-ray imaging, terahertz imaging can provide a safe and ionizing-radiation-free nondestructive inspection method for foreign object sensing. In this work, a quasi-Bessel beam (QBB known to be nondiffracting was generated by a conical dielectric lens to detect foreign objects in food samples. Using numerical evaluation via the finite-difference time-domain (FDTD method, the beam profiles of a QBB were evaluated and compared with the results obtained via analytical calculation and experimental characterization (knife edge method, point scanning method. The FDTD method enables a more precise estimation of the beam profile. Foreign objects in food samples, namely crickets, were then detected with the QBB, which had a deep focus and a high spatial resolution at 210 GHz. Transmitted images using a Gaussian beam obtained with a conventional lens were compared in the sub-terahertz frequency experimentally with those using a QBB generated using an axicon.

A high-precision system for conformal intracranial radiotherapy

International Nuclear Information System (INIS)

Tome, Wolfgang A.; Meeks, Sanford L.; Buatti, John M.; Bova, Francis J.; Friedman, William A.; Li Zuofeng

2000-01-01

Purpose: Currently, optimally precise delivery of intracranial radiotherapy is possible with stereotactic radiosurgery and fractionated stereotactic radiotherapy. We report on an optimally precise optically guided system for three-dimensional (3D) conformal radiotherapy using multiple noncoplanar fixed fields. Methods and Materials: The optically guided system detects infrared light emitting diodes (IRLEDs) attached to a custom bite plate linked to the patient's maxillary dentition. The IRLEDs are monitored by a commercially available stereo camera system, which is interfaced to a personal computer. An IRLED reference is established with the patient at the selected stereotactic isocenter, and the computer reports the patient's current position based on the location of the IRLEDs relative to this reference position. Using this readout from the computer, the patient may be dialed directly to the desired position in stereotactic space. The patient is localized on the first day and a reference file is established for 5 different couch positions. The patient's image data are then imported into a commercial convolution-based 3D radiotherapy planning system. The previously established isocenter and couch positions are then used as a template upon which to design a conformal 3D plan with maximum beam separation. Results: The use of the optically guided system in conjunction with noncoplanar radiotherapy treatment planning using fixed fields allows the generation of highly conformal treatment plans that exhibit a high degree of dose homogeneity and a steep dose gradient. To date, this approach has been used to treat 28 patients. Conclusion: Because IRLED technology improves the accuracy of patient localization relative to the linac isocenter and allows real-time monitoring of patient position, one can choose treatment-field margins that only account for beam penumbra and image resolution without adding margin to account for larger and poorly defined setup uncertainty. This

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

High-Precision Half-Life and Branching Ratio Measurements for the Superallowed β+ Emitter 26Alm

Science.gov (United States)

Finlay, P.; Svensson, C. E.; Demand, G. A.; Garrett, P. E.; Green, K. L.; Leach, K. G.; Phillips, A. A.; Rand, E. T.; Ball, G.; Bandyopadhyay, D.; Djongolov, M.; Ettenauer, S.; Hackman, G.; Pearson, C. J.; Leslie, J. R.; Andreoiu, C.; Cross, D.; Austin, R. A. E.; Grinyer, G. F.; Sumithrarachchi, C. S.; Williams, S. J.; Triambak, S.

2013-03-01

High-precision half-life and branching-ratio measurements for the superallowed β+ emitter 26Alm were performed at the TRIUMF-ISAC radioactive ion beam facility. An upper limit of ≤ 15 ppm at 90% C.L. was determined for the sum of all possible non-analogue β+/EC decay branches of 26Alm, yielding a superallowed branching ratio of 100.0000+0-0.0015%. A value of T1/2 = 6:34654(76) s was determined for the 26Alm half-life which is consistent with, but 2.5 times more precise than, the previous world average. Combining these results with world-average measurements yields an ft value of 3037.58(60) s, the most precisely determined for any superallowed emitting nucleus to date. This high-precision ft value for 26Alm provides a new benchmark to refine theoretical models of isospin-symmetry-breaking effects in superallowed β decays.

Target experiments with high-power proton beams

Energy Technology Data Exchange (ETDEWEB)

Baumung, K; Bluhm, H; Hoppe, P; Rusch, D; Singer, J; Stoltz, O [Forschungszentrum Karlsruhe (Germany); Kanel, G I; Razorenov, S V; Utkin, A V [Russian Academy of Sciences, Chernogolovka (Russian Federation). Inst. of Chemical Physics

1997-12-31

At the Karlsruhe Light Ion Facility KALE a pulsed high-power proton beam (50 ns, 0.15 TW/cm{sup 2}, 8 mm fwhm focus diameter, 1.7 MeV peak proton energy) is used to generate short, intense pressure pulses or to ablatively accelerate targets 10-100 {mu}m thick to velocities > 10 km/s. The velocity history of the rear target surface is recorded by line-imaging laser Doppler velocimetry with high spatial ({>=} 10 {mu}m) and temporal ({>=} 200 ps) resolution, and provides information on proton beam parameters, and on the state of the matter at high energy densities and intense loading. Utilizing the bell-shaped power density profile the authors demonstrated a new straightforward method for measuring the shock pressure that leads to material melting in the rarefaction wave. For the first time, the dynamic tensile strength was measured across a crystal grain boundary, and using targets with a 1D periodic structure, the growth rate of a Rayleigh Taylor instability could be measured for the first time in direct drive experiments with an ion beam. (author). 8 figs., 15 refs.

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

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

International Nuclear Information System (INIS)

Saadatmand, K.; Johnson, K.F.; Schneider, J.D.

1991-01-01

A visual diagnostic technique has been developed to monitor and study ion beam structure shape and size along a transport line. In this technique, a commercially available fluorescent screen is utilized in conjunction with a video camera. This visual representation of the beam structure is digitized and enhanced through use of false-color coding and displayed on a TV monitor for on-line viewing. Digitized information is stored for further off-line processing (e.g., extraction of beam profiles). An optional wire grid placed upstream of the fluor screen adds the capability of transverse emittance (or angular spread) measurement to this technique. This diagnostic allows real-time observation of the beam response to parameter changes (e.g., evolution of the beam structure, shifts in the beam intensity at various spatial locations within the beam perimeter, and shifts in the beam center and position). 3 refs., 5 figs

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.

High-precision positioning system of four-quadrant detector based on the database query

Science.gov (United States)

Zhang, Xin; Deng, Xiao-guo; Su, Xiu-qin; Zheng, Xiao-qiang

2015-02-01

The fine pointing mechanism of the Acquisition, Pointing and Tracking (APT) system in free space laser communication usually use four-quadrant detector (QD) to point and track the laser beam accurately. The positioning precision of QD is one of the key factors of the pointing accuracy to APT system. A positioning system is designed based on FPGA and DSP in this paper, which can realize the sampling of AD, the positioning algorithm and the control of the fast swing mirror. We analyze the positioning error of facular center calculated by universal algorithm when the facular energy obeys Gauss distribution from the working principle of QD. A database is built by calculation and simulation with MatLab software, in which the facular center calculated by universal algorithm is corresponded with the facular center of Gaussian beam, and the database is stored in two pieces of E2PROM as the external memory of DSP. The facular center of Gaussian beam is inquiry in the database on the basis of the facular center calculated by universal algorithm in DSP. The experiment results show that the positioning accuracy of the high-precision positioning system is much better than the positioning accuracy calculated by universal algorithm.

High precision neutron polarization for PERC

International Nuclear Information System (INIS)

Klauser, C.

2013-01-01

The decay of the free neutron into a proton, an electron and an anti-electron neutrino offers a simple system to study the semi-leptonic weak decay. High precision measurements of angular correlation coefficients of this decay provide the opportunity to test the standard model on the low energy frontier. The Proton Electron Radiation Channel PERC is part of a new generation of expriments pushing the accuracy of such an angular correlation coefficient measurement towards 10 -4 . Past experiments have been limited to an accuracy of 10 -3 with uncertainties on the neutron polarization as one of the leading systematic errors. This thesis focuses on the development of a stable, highly precise neutron polarization for a large, divergent cold neutron beam. A diagnostic tool that provides polarization higher than 99.99 % and analyzes with an accuracy of 10 -4 , the Opaque Test Bench, is presented and validated. It consists of two highly opaque polarized helium cells. The Opaque Test Bench reveals depolarizing effects in polarizing supermirrors commonly used for polarization in neutron decay experiments. These effects are investigated in detail. They are due to imperfect lateral magnetization in supermirror layers and can be minimized by significantly increased magnetizing fields and low incidence angle and supermirror factor m. A subsequent test in the crossed (X-SM) geometry demonstrated polarizations up to 99.97% from supermirrors only, improving neutron polarization with supermirrors by an order of magnitude. The thesis also discusses other neutron optical components of the PERC beamline: Monte-Carlo simulations of the beamline under consideration of the primary guide are carried out. In addition, calculation shows that PERC would statistically profit from an installation at the European Spallation source. Furthermore, beamline components were tested. A radio-frequency spin flipper was confirmed to work with an efficiency higher than 0.9999. (author) [de

Mode profiling of optical fibers at high laser powers

DEFF Research Database (Denmark)

Nielsen, Peter Carøe; Pedersen, David Bue; Simonsen, R.B.

2008-01-01

of the focused spot can be determined. The analyser is based on the principle of a rotating wire being swept though the laser beam, while the reflected signal is recorded [1]. By changing the incident angle of the rotating rod from 0° to 360° in relation to the fiber, the full profile of the laser beam...... is obtained. Choosing a highly reflective rod material and a sufficiently high rotation speed, these measurements can be done with high laser powers, without any additional optical elements between the fiber and analyzer. The performance of the analyzer was evaluated by coupling laser light into different...

Autocalibration of high precision drift tubes

International Nuclear Information System (INIS)

Bacci, C.; Bini, C.; Ciapetti, G.; De Zorzi, G.; Gauzzi, P.; Lacava, F.; Nisati, A.; Pontecorvo, L.; Rosati, S.; Veneziano, S.; Cambiaghi, M.; Casellotti, G.; Conta, C.; Fraternali, M.; Lanza, A.; Livan, M.; Polesello, G.; Rimoldi, A.; Vercesi, V.

1997-01-01

We present the results on MDT (monitored drift tubes) autocalibration studies obtained from the analysis of the data collected in Summer 1995 on the H8B Muon Test Beam. In particular we studied the possibility of autocalibration of the MDT using four or three layers of tubes, and we compared the calibration obtained using a precise external tracker with the output of the autocalibration procedure. Results show the feasibility of autocalibration with four and three tubes and the good accuracy of the autocalibration procedure. (orig.)

Beam halo in high-intensity beams

International Nuclear Information System (INIS)

Wangler, T.P.

1993-01-01

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

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.

Precise focusing and diagnosis technology for laser beams in ICF target chamber

International Nuclear Information System (INIS)

Zhu Qixiang

1999-01-01

The precise focusing and diagnosis experimental system for laser beams in ICF target chamber is introduced. The system is controlled by computer. In process of focusing a series data of displacement in axial direction and relative area of focus spots are acquired. According to the functional curvature the accurate position of focal plane is determined. The construction of the system is simple, the system is controlled conveniently and runs quickly

Electron beam irradiation facility for low to high dose irradiation applications

International Nuclear Information System (INIS)

Petwal, V.C.; Wanmode, Yashwant; Verma, Vijay Pal; Bhisikar, Abhay; Dwivedi, Jishnu; Shrivastava, P.; Gupta, P.D.

2013-01-01

Electron beam based irradiation facilities are becoming more and more popular over the conventional irradiator facilities due to many inherent advantages such as tunability of beam energy, availability of radiation both in electron mode and X-ray mode, wide range of the dose rate, control of radiation from a ON-OFF switch and other safety related merits. A prototype experimental facility based on electron accelerator has been set-up at RRCAT to meet the low-dose, medium dose and high-dose requirements for radiation processing of food, agricultural and medical products. The facility can be operated in the energy range from 7-10 MeV at variable power level from 0.05-3 kW to meet the dose rate requirement of 100 Gy to kGy. The facility is also equipped with a Bremsstrahlung converter optimized for X-ray irradiation at 7.5 MV. Availability of dose delivery in wide range with precision control and measurement has made the facility an excellent tool for researchers interested in electron/X-ray beam irradiation. A precision dosimetry lab based on alanine EPR and radiochromic film dosimetry system have been established to characterize the radiation field and precise dose measurements. Electron beam scattering technique has been developed to achieve low dose requirement for EB irradiation of various seeds such as groundnut, wheat, soybeans, moong beans, black gram etc. for mutation related studies. This paper describes various features of the facility together with the dosimetric measurements carried out for qualification of the facility and recent irradiation experiments carried out using this facility. (author)

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-...

Fundamentals and industrial applications of high power laser beam cladding

International Nuclear Information System (INIS)

Bruck, G.J.

1988-01-01

Laser beam cladding has been refined such that clad characteristics are precisely determined through routine process control. This paper reviews the state of the art of laser cladding optical equipment, as well as the fundamental process/clad relationships that have been developed for high power processing. Major categories of industrial laser cladding are described with examples chose to highlight particular process attributes

Trapezoidal diffraction grating beam splitters in single crystal diamond

Science.gov (United States)

Kiss, Marcell; Graziosi, Teodoro; Quack, Niels

2018-02-01

Single Crystal Diamond has been recognized as a prime material for optical components in high power applications due to low absorption and high thermal conductivity. However, diamond microstructuring remains challenging. Here, we report on the fabrication and characterization of optical diffraction gratings exhibiting a symmetric trapezoidal profile etched into a single crystal diamond substrate. The optimized grating geometry diffracts the transmitted optical power into precisely defined proportions, performing as an effective beam splitter. We fabricate our gratings in commercially available single crystal CVD diamond plates (2.6mm x 2.6mm x 0.3mm). Using a sputter deposited hard mask and patterning by contact lithography, the diamond is etched in an inductively coupled oxygen plasma with zero platen power. The etch process effectively reveals the characteristic {111} diamond crystal planes, creating a precisely defined angled (54.7°) profile. SEM and AFM measurements of the fabricated gratings evidence the trapezoidal shape with a pitch of 3.82μm, depth of 170 nm and duty cycle of 35.5%. Optical characterization is performed in transmission using a 650nm laser source perpendicular to the sample. The recorded transmitted optical power as function of detector rotation angle shows a distribution of 21.1% in the 0th order and 23.6% in each +/-1st order (16.1% reflected, 16.6% in higher orders). To our knowledge, this is the first demonstration of diffraction gratings with trapezoidal profile in single crystal diamond. The fabrication process will enable beam splitter gratings of custom defined optical power distribution profiles, while antireflection coatings can increase the efficiency.

Two Profiles of the Dutch High Performing Employee

Science.gov (United States)

de Waal, A. A.; Oudshoorn, Michella

2015-01-01

Purpose: The purpose of this study is to explore the profile of an ideal employee, to be more precise the behavioral characteristics of the Dutch high-performing employee (HPE). Organizational performance depends for a large part on the commitment of employees. Employees provide their knowledge, skills, experiences and creativity to the…

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

STANFORD (SLAC): Precision electroweak result

International Nuclear Information System (INIS)

Anon.

1994-01-01

Precision testing of the electroweak sector of the Standard Model has intensified with the recent publication* of results from the SLD collaboration's 1993 run on the Stanford Linear Collider, SLC. Using a highly polarized electron beam colliding with an unpolarized positron beam, SLD physicists measured the left-right asymmetry at the Z boson resonance with dramatically improved accuracy over 1992

P2. A fused silica Cherenkov detector for the high precision determination of the weak mixing angle

Energy Technology Data Exchange (ETDEWEB)

Gerz, Kathrin; Becker, Dominik; Jennewein, Thomas; Baunack, Sebastian [Johannes Gutenberg Universitaet Mainz (Germany); Kumar, Krishna [Department of Physics and Astronomy, Stony Brook University, Stony Brook (United States); Maas, Frank [Johannes Gutenberg Universitaet Mainz (Germany); Helmholtz Institut Mainz (Germany)

2016-07-01

The weak mixing angle is a central parameter of the standard model and its high precision determination is tantamount to probing for new physics effects. The P2 experiment at the MESA accelerator in Mainz will perform such a measurement of the weak mixing angle via parity violating electron-proton scattering. We aim to determine sin{sup 2}(Θ{sub W}) to a relative precision of 0.13%. Since the weak charge of the proton is small compared to its electric charge, the measurable asymmetry is only 33 ppb, requiring a challenging measurement to a precision of only 0.44 ppb. In order to achieve this precision we need to collect very high statistics and carefully minimize interfering effects like apparatus induced false asymmetries. We present the status of the development of an integrating fused-silica Cherenkov detector, which is suitable for a high precision and high intensity experiment like P2. The contribution will focus on the investigation of the detector's response to incoming signal and background particles both by simulations and by beam tests at the MAMI accelerator.

Local high precision 3D measurement based on line laser measuring instrument

Science.gov (United States)

Zhang, Renwei; Liu, Wei; Lu, Yongkang; Zhang, Yang; Ma, Jianwei; Jia, Zhenyuan

2018-03-01

In order to realize the precision machining and assembly of the parts, the geometrical dimensions of the surface of the local assembly surfaces need to be strictly guaranteed. In this paper, a local high-precision three-dimensional measurement method based on line laser measuring instrument is proposed to achieve a high degree of accuracy of the three-dimensional reconstruction of the surface. Aiming at the problem of two-dimensional line laser measuring instrument which lacks one-dimensional high-precision information, a local three-dimensional profile measuring system based on an accurate single-axis controller is proposed. First of all, a three-dimensional data compensation method based on spatial multi-angle line laser measuring instrument is proposed to achieve the high-precision measurement of the default axis. Through the pretreatment of the 3D point cloud information, the measurement points can be restored accurately. Finally, the target spherical surface is needed to make local three-dimensional scanning measurements for accuracy verification. The experimental results show that this scheme can get the local three-dimensional information of the target quickly and accurately, and achieves the purpose of gaining the information and compensating the error for laser scanner information, and improves the local measurement accuracy.

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

High-precision half-life determination for 21Na using a 4 π gas-proportional counter

Science.gov (United States)

Finlay, P.; Laffoley, A. T.; Ball, G. C.; Bender, P. C.; Dunlop, M. R.; Dunlop, R.; Hackman, G.; Leslie, J. R.; MacLean, A. D.; Miller, D.; Moukaddam, M.; Olaizola, B.; Severijns, N.; Smith, J. K.; Southall, D.; Svensson, C. E.

2017-08-01

A high-precision half-life measurement for the superallowed β+ transition between the isospin T =1 /2 mirror nuclei 21Na and 21Ne has been performed at the TRIUMF-ISAC radioactive ion beam facility yielding T1 /2=22.4506 (33 ) s, a result that is a factor of 4 more precise than the previous world-average half-life for 21Na and represents the single most precisely determined half-life for a transition between mirror nuclei to date. The contribution to the uncertainty in the 21Na F tmirror value due to the half-life is now reduced to the level of the nuclear-structure-dependent theoretical corrections, leaving the branching ratio as the dominant experimental uncertainty.

In-beam PET at high-energy photon beams: a feasibility study

Science.gov (United States)

Müller, H.; Enghardt, W.

2006-04-01

For radiation therapy with carbon ion beams, either for the stable isotope 12C or for the radioactive one 11C, it has been demonstrated that the β+-activity distribution created or deposited, respectively, within the irradiated volume can be visualized by means of positron emission tomography (PET). The PET images provide valuable information for quality assurance and precision improvement of ion therapy. Dedicated PET scanners have been integrated into treatment sites at the Heavy Ion Medical Accelerator at Chiba (HIMAC), Japan, and the Gesellschaft für Schwerionenforschung (GSI), Germany, to make PET imaging feasible during therapeutic irradiation (in-beam PET). A similar technique may be worthwhile for radiotherapy with high-energy bremsstrahlung. In addition to monitoring the dose delivery process which in-beam PET has been primarily developed for, it may be expected that radiation response of tissue can be detected by means of in-beam PET. We investigate the applicability of PET for treatment control in the case of using bremsstrahlung spectra produced by 15-50 MeV electrons. Target volume activation due to (γ, n) reactions at energies above 20 MeV yields moderate β+-activity levels, which can be employed for imaging. The radiation from positrons produced by pair production is not presently usable because the detectors are overloaded due to the low duty factor of medical electron linear accelerators. However, the degradation of images caused by positron motion between creation and annihilation seems to be tolerable.

MHD phenomena in a neutral beam heated high beta, low qa disruption

International Nuclear Information System (INIS)

Chu, M.S.; Greene, J.M.; Kim, J.S.; Lao, L.; Snider, R.T.; Stambaugh, R.D.; Strait, E.J.; Taylor, T.S.

1988-01-01

A neutral beam heated, β maximizing discharge at low q a in Doublet III ending in disruption is studied and correlated with theoretical models. This discharge achieved MHD β-values close to the theoretical Troyon-Sykes-Wesson limit in its evolution. The MHD phenomena of this discharge are analysed. The sequence of events leading to the high β disruptions is hypothesized as follows: the current and pressure profiles are broadened continuously by neutral beam injection. A last sawtooth internal disruption initiates an (m/n = 2/1) island through current profile steepening around the q=2 surface. The loss of plasma through stochastic field lines slows the island rotation and enhances its interaction with the limiter. The resultant enhanced island growth through island cooling or profile change enlarged the edge stochastic region. The overlapping of the edge stochastic region with the sawtooth mixing region precipitated the pressure disruption. Thus, in our hypothetical model for this discharge, β increase by neutral beam heating does not directly cause the disruption but ushers the plasma indirectly towards it through the profile broadening process and contributes to the destabilization of the 1/1 and 2/1 tearing modes. (author). 26 refs, 12 figs

High resolution laser spectroscopy as a diagnostic tool in beams

International Nuclear Information System (INIS)

Bergmann, K.; Hefter, U.; Hering, P.

1977-01-01

The combination of high resolution laser spectroscopy with the technique of molecular beams allows a very detailed beam research since molecules or atoms in specific quantum states can be sampled yielding previously unavailable sources of data. In these experiments a Na/Na 2 beam emerges from a 0.2 mm nozzle and is collimated by a 2 mm wide slit 50 cm downstream. To probe the molecules a single mode Ar + -laser was used which can be tuned within the gain profile of the laser line (8 GHz) to several transitions between specific levels in the ground state and second electronically excited state of the Na 2 molecule. (Auth.)

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.

Apparatus for precision micromachining with lasers

Science.gov (United States)

Chang, J.J.; Dragon, E.P.; Warner, B.E.

1998-04-28

A new material processing apparatus using a short-pulsed, high-repetition-rate visible laser for precision micromachining utilizes a near diffraction limited laser, a high-speed precision two-axis tilt-mirror for steering the laser beam, an optical system for either focusing or imaging the laser beam on the part, and a part holder that may consist of a cover plate and a back plate. The system is generally useful for precision drilling, cutting, milling and polishing of metals and ceramics, and has broad application in manufacturing precision components. Precision machining has been demonstrated through percussion drilling and trepanning using this system. With a 30 W copper vapor laser running at multi-kHz pulse repetition frequency, straight parallel holes with size varying from 500 microns to less than 25 microns and with aspect ratios up to 1:40 have been consistently drilled with good surface finish on a variety of metals. Micromilling and microdrilling on ceramics using a 250 W copper vapor laser have also been demonstrated with good results. Materialographic sections of machined parts show little (submicron scale) recast layer and heat affected zone. 1 fig.

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

Beam-target interaction for high-dose, multi-pulse radiography

International Nuclear Information System (INIS)

DeVolder, B.G.; Kwan, T.J.T.; Snell, C.M.; Kares, R.J.; McLenithan, K.D.

1996-01-01

The conversion of an intense relativistic electron beam into x-rays for radiographic imaging is achieved through the bremsstrahlung process of electrons in a tantalum or tungsten target of some optimal thickness. A high-dose radiographic source with small spot size is needed to achieve desirable resolution for thick objects. Consequently, an extremely high brightness electron beam is used and a significant amount of electron beam energy can be deposited in a small area of the target. The authors describe a computational methodology used to model the beam-target interaction and the evolution of the resultant plasma. Several codes, including particle-in-cell (PIC), Monte Carlo transport, and magnetohydrodynamic (MHD) codes, contribute to simulate different parts of the problem in a linked fashion. Issues addressed by the calculations include: the effects of the time dependence of the energy profile deposited in the target; the influence of the external magnetic field on plasma expansion; the influence of the expanding plasma on the guide magnetic field; radiation effects; and multi-dimensional effects

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.

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.

High Precision Current Control for the LHC Main Power Converters

CERN Document Server

Thiesen, H; Hudson, G; King, Q; Montabonnet, V; Nisbet, D; Page, S

2010-01-01

Since restarting at the end of 2009, the LHC has reached a new energy record in March 2010 with the two 3.5 TeV beams. To achieve the performance required for the good functioning of the accelerator, the currents in the main circuits (Main Bends and Main Quadrupoles) must be controlled with a higher precision than ever previously requested for a particle accelerator at CERN: a few parts per million (ppm) of nominal current. This paper describes the different challenges that were overcome to achieve the required precision for the current control of the main circuits. Precision tests performed during the hardware commissioning of the LHC illustrate this paper.

High-resolution electron collision spectroscopy with multicharged ions in merged beams

Energy Technology Data Exchange (ETDEWEB)

Lestinsky, M.

2007-04-18

The Heidelberg ion storage ring Tsr is currently the only ring equipped with two independent devices for the collinear merging of a cold electron beam with stored ions. This greatly improves the potential of electron-ion collision experiments, as the ion beam can be cooled with one electron beam, while the other one is used as a dedicated target for energy-resolved electron collision processes, such as recombination. The work describes the implementation of this system for rst electron collision spectroscopy experiments. A detection system has been realized including an ion detector and specroscopic beam-control software and instrumentation. Moreover, in order to improve the spectroscopic resolution systematical studies of intrinsic relaxation processes in the electron beam have been carried out. These include the dependence on the electron beam density, the magnetic guiding eld strength, and the acceleration geometry. The recombination measurements on low-lying resonances in lithiumlike Sc{sup 18+} yield a high-precision measurement of the 2s-2p{sub 3/2} transition energy in this system. Operation of the two-electron-beam setup at high collision energy ({approx}1000 eV) is established using resonances of hydrogenlike Mg{sup 11+}, while the unique possibility of modifying the beam-merging geometry con rms its importance for the electron-ion recombination rate at lowest relative energy, as demonstrated on F{sup 6+}. (orig.)

High-resolution electron collision spectroscopy with multicharged ions in merged beams

International Nuclear Information System (INIS)

Lestinsky, M.

2007-01-01

The Heidelberg ion storage ring Tsr is currently the only ring equipped with two independent devices for the collinear merging of a cold electron beam with stored ions. This greatly improves the potential of electron-ion collision experiments, as the ion beam can be cooled with one electron beam, while the other one is used as a dedicated target for energy-resolved electron collision processes, such as recombination. The work describes the implementation of this system for rst electron collision spectroscopy experiments. A detection system has been realized including an ion detector and specroscopic beam-control software and instrumentation. Moreover, in order to improve the spectroscopic resolution systematical studies of intrinsic relaxation processes in the electron beam have been carried out. These include the dependence on the electron beam density, the magnetic guiding eld strength, and the acceleration geometry. The recombination measurements on low-lying resonances in lithiumlike Sc 18+ yield a high-precision measurement of the 2s-2p 3/2 transition energy in this system. Operation of the two-electron-beam setup at high collision energy (∼1000 eV) is established using resonances of hydrogenlike Mg 11+ , while the unique possibility of modifying the beam-merging geometry con rms its importance for the electron-ion recombination rate at lowest relative energy, as demonstrated on F 6+ . (orig.)

High precision measurements of 26Naβ- decay

Science.gov (United States)

Grinyer, G. F.; Svensson, C. E.; Andreoiu, C.; Andreyev, A. N.; Austin, R. A.; Ball, G. C.; Chakrawarthy, R. S.; Finlay, P.; Garrett, P. E.; Hackman, G.; Hardy, J. C.; Hyland, B.; Iacob, V. E.; Koopmans, K. A.; Kulp, W. D.; Leslie, J. R.; MacDonald, J. A.; Morton, A. C.; Ormand, W. E.; Osborne, C. J.; Pearson, C. J.; Phillips, A. A.; Sarazin, F.; Schumaker, M. A.; Scraggs, H. C.; Schwarzenberg, J.; Smith, M. B.; Valiente-Dobón, J. J.; Waddington, J. C.; Wood, J. L.; Zganjar, E. F.

2005-04-01

High-precision measurements of the half-life and β-branching ratios for the β- decay of 26Na to 26Mg have been measured in β-counting and γ-decay experiments, respectively. A 4π proportional counter and fast tape transport system were employed for the half-life measurement, whereas the γ rays emitted by the daughter nucleus 26Mg were detected with the 8π γ-ray spectrometer, both located at TRIUMF's isotope separator and accelerator radioactive beam facility. The half-life of 26Na was determined to be T1/2=1.07128±0.00013±0.00021s, where the first error is statistical and the second systematic. The logft values derived from these experiments are compared with theoretical values from a full sd-shell model calculation.

High precision innovative micropump for artificial pancreas

Science.gov (United States)

Chappel, E.; Mefti, S.; Lettieri, G.-L.; Proennecke, S.; Conan, C.

2014-03-01

The concept of artificial pancreas, which comprises an insulin pump, a continuous glucose meter and a control algorithm, is a major step forward in managing patient with type 1 diabetes mellitus. The stability of the control algorithm is based on short-term precision micropump to deliver rapid-acting insulin and to specific integrated sensors able to monitor any failure leading to a loss of accuracy. Debiotech's MEMS micropump, based on the membrane pump principle, is made of a stack of 3 silicon wafers. The pumping chamber comprises a pillar check-valve at the inlet, a pumping membrane which is actuated against stop limiters by a piezo cantilever, an anti-free-flow outlet valve and a pressure sensor. The micropump inlet is tightly connected to the insulin reservoir while the outlet is in direct communication with the patient skin via a cannula. To meet the requirement of a pump dedicated to closed-loop application for diabetes care, in addition to the well-controlled displacement of the pumping membrane, the high precision of the micropump is based on specific actuation profiles that balance effect of pump elasticity in low-consumption push-pull mode.

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)

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.

Edge density profiles in high-performance JET plasmas

International Nuclear Information System (INIS)

Summers, D.D.R.; Viaccoz, B.; Vince, J.

1997-01-01

Detailed electron density profiles of the scrape-off layer in high-performance JET plasmas (plasma current, I p nbi ∝17 MW) have been measured by means of a lithium beam diagnostic system featuring high spatial resolution [Kadota (1978)[. Measurements were taken over a period of several seconds, allowing examination of the evolution of the edge profile at a location upstream from the divertor target. The data clearly show the effects of the H-mode transition - an increase in density near the plasma separatrix and a reduction in density scrape-off length. The profiles obtained under various plasma conditions are compared firstly with data from other diagnostics, located elsewhere in the vessel, and also with the predictions of an 'onion-skin' model (DIVIMP), which used, as initial parameters, data from an array of probes located in the divertor target. (orig.)

Simulation of the Beam Dump for a High Intensity Electron Gun

CERN Document Server

Doebert, S; Lefevre, T; Pepitone, K

2014-01-01

The CLIC Drive Beam is a high-intensity pulsed electron beam. A test facility for the Drive Beam electron gun will soon be commissioned at CERN. In this contribution we outline the design of a beam dump / Faraday cup capable of resisting the beam’s thermal load. The test facility will operate initially up to 140 keV. At such low energies, the electrons are absorbed very close to the surface of the dump, leading to a large energy deposition density in this thin layer. In order not to damage the dump, the beam must be spread over a large surface. For this reason, a small-angled cone has been chosen. Simulations using Geant4 have been performed to estimate the distribution of energy deposition in the dump. The heat transport both within the electron pulse and between pulses has been modelled using finite element methods to check the resistance of the dump at high repetition rates. In addition, the possibility of using a moveable dump to measure the beam profile and emittance is discussed.

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.

IOP Latest R&D news and beam test performance of the highly granular SiW-ECAL technological prototype for the ILC

CERN Document Server

Irles, Adrián

2018-02-22

High precision physics at future colliders as the International Linear Collider (ILC) require unprecedented high precision in the determination of the energy of final state particles. The needed precision will be achieved thanks to the Particle Flow algorithms (PF) which require highly granular and hermetic calorimeters systems. The physical proof of concept of the PF was performed in the previous campaign of beam tests of physic prototypes within the CALICE collaboration. One of these prototypes was the physics prototype of the Silicon-Tungsten Electromagnetic Calorimeter (SiW-ECAL) for the International Large Detector at the ILC. In this document we present the latest nes on R&D of the next generation prototype, the technological prototype with fully embedded very front-end (VFE) electronics, of the SiW-ECAL. Special emphasis is given to the presentation and discussion of the first results from the beam test done at DESY in June 2017. The physics program for such beam test consisted in the calibration a...

A high-finesse Fabry–Perot cavity with a frequency-doubled green laser for precision Compton polarimetry at Jefferson Lab

International Nuclear Information System (INIS)

Rakhman, A.; Hafez, M.; Nanda, S.; Benmokhtar, F.; Camsonne, A.; Cates, G.D.; Dalton, M.M.; Franklin, G.B.; Friend, M.; Michaels, R.W.; Nelyubin, V.; Parno, D.S.; Paschke, K.D.; Quinn, B.P.

2016-01-01

A high-finesse Fabry–Perot cavity with a frequency-doubled continuous wave green laser (532 nm) has been built and installed in Hall A of Jefferson Lab for high precision Compton polarimetry. The infrared (1064 nm) beam from a ytterbium-doped fiber amplifier seeded by a Nd:YAG nonplanar ring oscillator laser is frequency doubled in a single-pass periodically poled MgO:LiNbO_3 crystal. The maximum achieved green power at 5 W infrared pump power is 1.74 W with a total conversion efficiency of 34.8%. The green beam is injected into the optical resonant cavity and enhanced up to 3.7 kW with a corresponding enhancement of 3800. The polarization transfer function has been measured in order to determine the intra-cavity circular laser polarization within a measurement uncertainty of 0.7%. The PREx experiment at Jefferson Lab used this system for the first time and achieved 1.0% precision in polarization measurements of an electron beam with energy and current of 1.06 GeV and 50 μA.

A high-finesse Fabry–Perot cavity with a frequency-doubled green laser for precision Compton polarimetry at Jefferson Lab

Energy Technology Data Exchange (ETDEWEB)

Rakhman, A., E-mail: rahim@ornl.gov [Syracuse University, Department of Physics, Syracuse, NY 13244 (United States); Research Accelerator Division, Spallation Neutron Source, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Hafez, M. [Old Dominion University, Applied Research Center, Norfolk, VA 23529 (United States); Nanda, S. [Thomas Jefferson National Accelerator Facility, Newport News, VA 23606 (United States); Benmokhtar, F. [Carnegie Mellon University, Department of Physics, Pittsburgh, PA 15213 (United States); Duquesne University, Pittsburgh, PA 15282 (United States); Camsonne, A. [Thomas Jefferson National Accelerator Facility, Newport News, VA 23606 (United States); Cates, G.D. [University of Virginia, Department of Physics, Charlottesville, VA 22904 (United States); Dalton, M.M. [Thomas Jefferson National Accelerator Facility, Newport News, VA 23606 (United States); University of Virginia, Department of Physics, Charlottesville, VA 22904 (United States); Franklin, G.B. [Carnegie Mellon University, Department of Physics, Pittsburgh, PA 15213 (United States); Friend, M. [Carnegie Mellon University, Department of Physics, Pittsburgh, PA 15213 (United States); High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki (Japan); Michaels, R.W. [Thomas Jefferson National Accelerator Facility, Newport News, VA 23606 (United States); Nelyubin, V. [University of Virginia, Department of Physics, Charlottesville, VA 22904 (United States); Parno, D.S. [Carnegie Mellon University, Department of Physics, Pittsburgh, PA 15213 (United States); University of Washington, Center for Experimental Nuclear Physics and Astrophysics and Department of Physics, Seattle, WA 98195 (United States); Paschke, K.D. [University of Virginia, Department of Physics, Charlottesville, VA 22904 (United States); Quinn, B.P. [Carnegie Mellon University, Department of Physics, Pittsburgh, PA 15213 (United States); and others

2016-06-21

A high-finesse Fabry–Perot cavity with a frequency-doubled continuous wave green laser (532 nm) has been built and installed in Hall A of Jefferson Lab for high precision Compton polarimetry. The infrared (1064 nm) beam from a ytterbium-doped fiber amplifier seeded by a Nd:YAG nonplanar ring oscillator laser is frequency doubled in a single-pass periodically poled MgO:LiNbO{sub 3} crystal. The maximum achieved green power at 5 W infrared pump power is 1.74 W with a total conversion efficiency of 34.8%. The green beam is injected into the optical resonant cavity and enhanced up to 3.7 kW with a corresponding enhancement of 3800. The polarization transfer function has been measured in order to determine the intra-cavity circular laser polarization within a measurement uncertainty of 0.7%. The PREx experiment at Jefferson Lab used this system for the first time and achieved 1.0% precision in polarization measurements of an electron beam with energy and current of 1.06 GeV and 50 μA.

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.

A review of treatment planning for precision image-guided photon beam pre-clinical animal radiation studies

International Nuclear Information System (INIS)

Verhaegen, Frank; Hoof, Stefan van; Granton, Patrick V.; Trani, Daniela

2014-01-01

Recently, precision irradiators integrated with a high-resolution CT imaging device became available for pre-clinical studies. These research platforms offer significant advantages over older generations of animal irradiators in terms of precision and accuracy of image-guided radiation targeting. These platforms are expected to play a significant role in defining experiments that will allow translation of research findings to the human clinical setting. In the field of radiotherapy, but also others such as neurology, the platforms create unique opportunities to explore e.g. the synergy between radiation and drugs or other agents. To fully exploit the advantages of this new technology, accurate methods are needed to plan the irradiation and to calculate the three-dimensional radiation dose distribution in the specimen. To this end, dedicated treatment planning systems are needed. In this review we will discuss specific issues for precision irradiation of small animals, we will describe the workflow of animal treatment planning, and we will examine several dose calculation algorithms (factorization, superposition-convolution, Monte Carlo simulation) used for animal irradiation with kilovolt photon beams. Issues such as dose reporting methods, photon scatter, tissue segmentation and motion will also be discussed briefly.

Rigorous high-precision enclosures of fixed points and their invariant manifolds

Science.gov (United States)

Wittig, Alexander N.

The well established concept of Taylor Models is introduced, which offer highly accurate C0 enclosures of functional dependencies, combining high-order polynomial approximation of functions and rigorous estimates of the truncation error, performed using verified arithmetic. The focus of this work is on the application of Taylor Models in algorithms for strongly non-linear dynamical systems. A method is proposed to extend the existing implementation of Taylor Models in COSY INFINITY from double precision coefficients to arbitrary precision coefficients. Great care is taken to maintain the highest efficiency possible by adaptively adjusting the precision of higher order coefficients in the polynomial expansion. High precision operations are based on clever combinations of elementary floating point operations yielding exact values for round-off errors. An experimental high precision interval data type is developed and implemented. Algorithms for the verified computation of intrinsic functions based on the High Precision Interval datatype are developed and described in detail. The application of these operations in the implementation of High Precision Taylor Models is discussed. An application of Taylor Model methods to the verification of fixed points is presented by verifying the existence of a period 15 fixed point in a near standard Henon map. Verification is performed using different verified methods such as double precision Taylor Models, High Precision intervals and High Precision Taylor Models. Results and performance of each method are compared. An automated rigorous fixed point finder is implemented, allowing the fully automated search for all fixed points of a function within a given domain. It returns a list of verified enclosures of each fixed point, optionally verifying uniqueness within these enclosures. An application of the fixed point finder to the rigorous analysis of beam transfer maps in accelerator physics is presented. Previous work done by

Transverse phase space mapping of relativistic electron beams using optical transition radiation

Directory of Open Access Journals (Sweden)

G. P. Le Sage

1999-12-01

Full Text Available Optical transition radiation (OTR has proven to be a versatile and effective diagnostic for measuring the profile, divergence, and emittance of relativistic electron beams with a wide range of parameters. Diagnosis of the divergence of modern high brightness beams is especially well suited to OTR interference (OTRI techniques, where multiple dielectric or metal foils are used to generate a spatially coherent interference pattern. Theoretical analysis of measured OTR and OTRI patterns allows precise measurement of electron beam emittance characteristics. Here we describe an extension of this technique to allow mapping of divergence characteristics as a function of transverse coordinates within a measured beam. We present the first experimental analysis of the transverse phase space of an electron beam using all optical techniques. Comparing an optically masked portion of the beam to the entire beam, we measure different angular spread and average direction of the particles. Direct measurement of the phase-space ellipse tilt angle has been demonstrated using this optical masking technique.

Ultra-High Precision Half-Life Measurement for the Superallowed &+circ; Emitter ^26Al^m

Science.gov (United States)

Finlay, P.; Demand, G.; Garrett, P. E.; Leach, K. G.; Phillips, A. A.; Sumithrarachchi, C. S.; Svensson, C. E.; Triambak, S.; Grinyer, G. F.; Leslie, J. R.; Andreoiu, C.; Cross, D.; Austin, R. A. E.; Ball, G. C.; Bandyopadhyay, D.; Djongolov, M.; Ettenauer, S.; Hackman, G.; Pearson, C. J.; Williams, S. J.

2009-10-01

The calculated nuclear structure dependent correction for ^26Al^m (δC-δNS= 0.305(27)% [1]) is smaller by nearly a factor of two than the other twelve precision superallowed cases, making it an ideal case to pursue a reduction in the experimental errors contributing to the Ft value. An ultra-high precision half-life measurement for the superallowed &+circ; emitter ^26Al^m has been made at the Isotope Separator and Accelerator (ISAC) facility at TRIUMF in Vancouver, Canada. A beam of ˜10^5 ^26Al^m/s was delivered in October 2007 and its decay was observed using a 4π continuous gas flow proportional counter as part of an ongoing experimental program in superallowed Fermi β decay studies. With a statistical precision of ˜0.008%, the present work represents the single most precise measurement of any superallowed half-life to date. [4pt] [1] I.S. Towner and J.C. Hardy, Phys. Rev. C 79, 055502 (2009).

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.

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)

Transverse Laser Beam Shaping in High Brightness Electron Gun at ATF

CERN Document Server

Roychowdhury, S

2005-01-01

The brightness of electron beams from a photo injector is influenced by the transverse and longitudinal distribution of the laser beam illuminating the cathode. Previous studies at Brookhaven Accelerator Test Facility have shown that formation of an ideal e-beam with lowest transverse emittance requires uniform circular distribution of the emitted electrons. The use of the uniformly distributed power of the laser beam may not lead to that of the emitted electrons because of the non-uniform quantum efficiency. A proper shaping of the laser beam can compensate for this non-uniformity. In this paper we describe the use of digital light processing (DLP) technique based on digital mirror device (DMD) for spatial modulation of the laser beam, for measurements of the quantum efficiency map, and for creating the desirable e-beam density profiles. A DMD is aμelectronic mechanical system (MEMS) comprising of millions of highly reflectiveμmirrors controlled by underlying electronics. We present exper...

Initial Results on Neutralized Drift Compression Experiments (NDCX-IA) for High Intensity Ion Beam

CERN Document Server

Roy, Prabir K; Baca, David; Bieniosek, Frank; Coleman, Joshua E; Davidson, Ronald C; Efthimion, Philip; Eylon, Shmuel; Gilson, Erik P; Grant Logan, B; Greenway, Wayne; Henestroza, Enrique; Kaganovich, Igor D; Leitner, Matthaeus; Rose, David; Sefkow, Adam; Sharp, William M; Shuman, Derek; Thoma, Carsten H; Vanecek, David; Waldron, William; Welch, Dale; Yu, Simon

2005-01-01

Ion beam neutralization and compression experiments are designed to determine the feasibility of using compressed high intensity ion beams for high energy density physics (HEDP) experiments and for inertial fusion power. To quantitatively ascertain the various mechanisms and methods for beam compression, the Neutralized Drift Compression Experiment (NDCX) facility is being constructed at Lawrence Berkeley National Laboratory (LBNL). In the first compression experiment, a 260 KeV, 25 mA, K+ ion beam of centimeters size is radially compressed to a mm size spot by neutralization in a meter-long plasma column and beam peak current is longitudinally compressed by an induction velocity tilt core. Instrumentation, preliminary results of the experiments, and practical limits of compression are presented. These include parameters such as emittance, degree of neutralization, velocity tilt time profile, and accuracy of measurements (fast and spatially high resolution diagnostic) are discussed.

Enhancement of beam pulse controllability for a single-pulse formation system of a cyclotron

International Nuclear Information System (INIS)

Kurashima, Satoshi; Miyawaki, Nobumasa; Kashiwagi, Hirotsugu; Okumura, Susumu; Taguchi, Mitsumasa; Fukuda, Mitsuhiro

2015-01-01

The single-pulse formation technique using a beam chopping system consisting of two types of high-voltage beam kickers was improved to enhance the quality and intensity of the single-pulse beam with a pulse interval over 1 μs at the Japan Atomic Energy Agency cyclotron facility. A contamination rate of neighboring beam bunches in the single-pulse beam was reduced to less than 0.1%. Long-term purification of the single pulse beam was guaranteed by the well-controlled magnetic field stabilization system for the cyclotron magnet. Reduction of the multi-turn extraction number for suppressing the neighboring beam bunch contamination was achieved by restriction of a beam phase width and precise optimization of a particle acceleration phase. In addition, the single-pulse beam intensity was increased by a factor of two or more by a combination of two types of beam bunchers using sinusoidal and saw-tooth voltage waveforms. Provision of the high quality intense single-pulse beam contributed to improve the accuracy of experiments for investigation of scintillation light time-profile and for neutron energy measurement by a time-of-flight method

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

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.

Tune measurements with high intensity ion beams at GSI SIS-18

Energy Technology Data Exchange (ETDEWEB)

Singh, Rahul [GSI, Darmstadt (Germany); TEMF, TU Darmstadt (Germany); Forck, Peter; Kowina, Piotr; Kaufmann, Wolfgang [GSI, Darmstadt (Germany); Weiland, Thomas [TEMF, TU Darmstadt (Germany)

2012-07-01

A precise tune measurement during a full accelerating cycle is required to achieve stable high current operation. A new system has been commissioned at GSI for position, orbit and tune measurements. It consists of three distinct parts; an exciter which provides power to excite coherent betatron oscillations in the bunched beam; Fast ADCs to digitize the BPM signals at 125 MSa/s; the post processing electronics uses digitized BPM signals to acquire one position value per bunch. Subsequently the baseband tune is determined by Fourier transformation of the position data. Experiments were conducted to understand the effects of high beam intensity on tune at injection plateau (11.4 MeV/u) and during acceleration ramp (11.4-600 MeV/u). These experiments were performed with U{sup 73+} and Ar{sup 18+} ion beam at highest achievable intensities of 2.10{sup 9} and 2.5.10{sup 10} respectively. Tune shift with increased intensity was observed. The working principle of the tune measurement system and observed high intensity effects on tune will be reported in this contribution.

Tests of a Fast Plastic Scintillator for High-Precision Half-Life Measurements

Science.gov (United States)

Laffoley, A. T.; Dunlop, R.; Finlay, P.; Leach, K. G.; Michetti-Wilson, J.; Rand, E. T.; Svensson, C. E.; Grinyer, G. F.; Thomas, J. C.; Ball, G.; Garnsworthy, A. B.; Hackman, G.; Orce, J. N.; Triambak, S.; Williams, S. J.; Andreoiu, C.; Cross, D.

2013-03-01

A fast plastic scintillator detector is evaluated for possible use in an ongoing program of high-precision half-life measurements of short lived β emitters. Using data taken at TRI-UMF's Isotope Separator and Accelerator Facility with a radioactive 26Na beam, a detailed investigation of potential systematic effects with this new detector setup is being performed. The technique will then be applied to other β-decay half-life measurements including the superallowed Fermi β emitters 10C, 14O, and T = 1/2 decay of 15O.

High-precision branching-ratio measurement for the superallowed β+ emitter 26Alm

Science.gov (United States)

Finlay, P.; Ball, G. C.; Leslie, J. R.; Svensson, C. E.; Andreoiu, C.; Austin, R. A. E.; Bandyopadhyay, D.; Cross, D. S.; Demand, G.; Djongolov, M.; Ettenauer, S.; Garrett, P. E.; Green, K. L.; Grinyer, G. F.; Hackman, G.; Leach, K. G.; Pearson, C. J.; Phillips, A. A.; Rand, E. T.; Sumithrarachchi, C. S.; Triambak, S.; Williams, S. J.

2012-05-01

A high-precision branching-ratio measurement for the superallowed β+ emitter 26Alm was performed at the TRIUMF-ISAC radioactive ion beam facility. An upper limit of ⩽12 ppm at 90% confidence level was found for the second forbidden β+ decay of 26Alm to the 21+ state at 1809 keV in 26Mg. An inclusive upper limit of ⩽15 ppm at 90% confidence level was found when considering all possible nonanalog β+/EC decay branches of 26Alm, resulting in a superallowed branching ratio of 100.0000-0.0015+0%.

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

Physics of Eclipsing Binaries: Modelling in the new era of ultra-high precision photometry

OpenAIRE

Pavlovski, K.; Bloemen, S.; Degroote, P.; Conroy, K.; Hambleton, Kelly; Giammarco, J.M.; Pablo, H.; Prša, A.; Tkachenko, A.; Torres, G.

2013-01-01

Recent ultra-high precision observations of eclipsing binaries, especially data acquired by the Kepler satellite, have made accurate light curve modelling increasingly challenging but also more rewarding. In this contribution, we discuss low-amplitude signals in light curves that can now be used to derive physical information about eclipsing binaries but that were unaccessible before the Kepler era. A notable example is the detection of Doppler beaming, which leads to an increase in flux when...

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.

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

Present status and future aspects of highly precise radiotherapy

International Nuclear Information System (INIS)

Oita, Masataka; Takegawa, Yoshihiro; Maezawa, Hiroshi; Ikushima, Hitoshi; Osaki, Kyosuke; Nishitani, Hiromu

2006-01-01

This review describes about therapeutic equipments, irradiation technology, actual practice of highly precise radiotherapy (RT) and its tasks in future. Development of radiation equipments has made the therapy highly precise. At present, there are reportedly 836 linacs and 23 microtrons in Japan (March, 2005), most of which are computerized, new generation equipments. Image-guided RT, CT-linac system, real-time tumor-tracking RT (RTRT), tomotherapy and cyberknife are introduced owing to development of concerned devices and equipments. In addition, there are 7 facilities with proton and/or heavy ion beams. In parallel with the machine development above, irradiation has become to that from 2D to 3D by multi-gate technique with use of multi-leaf collimator and intensity-modulated RT is introduced. RTRT is an example of 4D RT. Practically, stereotactic irradiation (STI) to brain tumor has resulted in 1-year cumulative survival rate of 58% in 16 cases (23 foci, median size 1.2 cm and volume 0.57 ml) with median dose of 21.0 Gy in authors' hospital. STI in the early stage lung cancers is also practically conducted without severe adverse effects. Future tasks involve the further development of irradiation techniques and RT planning, QA/QC system, and raising of experts in related fields, which is a national problem. (T.I.)

High-Energy Beam Transport system

International Nuclear Information System (INIS)

Melson, K.E.; Farrell, J.A.; Liska, D.J.

1979-01-01

The High-Energy Beam Transport (HEBT) system for the Fusion Materials Irradiation Test (FMIT) Facility is to be installed at the Hanford Engineering Development Laboratory (HEDL) at Richland, Washington. The linear accelerator must transport a large emittance, high-current, high-power, continuous-duty deuteron beam with a large energy spread either to a lithium target or a beam stop. A periodic quadrupole and bending-magnet system provides the beam transport and focusing on target with small beam aberrations. A special rf cavity distributes the energy in the beam so that the Bragg Peak is distributed within the lithium target. Operation of the rf control system, the Energy Dispersion Cavity (EDC), and the beam transport magnets is tested on the beam stop during accelerator turn-on. Characterizing the beam will require extensions of beam diagnostic techniques and noninterceptive sensors. Provisions are being made in the facility for suspending the transport system from overhead supports using a cluster system to simplify maintenance and alignment techniques

The physics of high current beams

International Nuclear Information System (INIS)

Lawson, J.D.

1988-05-01

An outline is presented of paraxial charged particle optics in the presence of self-fields arising from the space-charge and current carried by the beam. Solutions of the envelope equations for beams with finite emittance are considered for a number of specific situations, with the approximation that the density profile of the beam is uniform with a sharp edge, so that the focusing remains linear. More realistic beams are then considered, and the problems of matching, emittance growth and stability are discussed. An attempt is made to emphasize physical principles and physical ideas rather than to present the detailed mathematical techniques required for specific problems. The approach is a tutorial one, and several 'exercises' are included in the text. Most of the material is treated in more depth in the author's forthcoming book. (author)

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 ....

Atomic physics of highly charged ions in an electron beam ion trap

International Nuclear Information System (INIS)

Marrs, R.E.

1990-07-01

Two electron beam ion traps are in use at LLNL for the purpose of studying the properties of very highly charged ions and their interactions with electrons. This paper reviews the operation of the traps and discusses recent experiments in three areas: precision transition energy measurements in the limit of very high ion charge, dielectronic recombination measurements for the He-like isoelectronic sequence, and measurements of x-ray polarization. 22 refs., 11 figs., 1 tab

Ultra-High Density Electron Beams for Beam Radiation and Beam Plasma Interaction

CERN Document Server

Anderson, Scott; Frigola, Pedro; Gibson, David J; Hartemann, Fred V; Jacob, Jeremy S; Lim, Jae; Musumeci, Pietro; Rosenzweig, James E; Travish, Gil; Tremaine, Aaron M

2005-01-01

Current and future applications of high brightness electron beams, which include advanced accelerators such as the plasma wake-field accelerator (PWFA) and beam-radiation interactions such as inverse-Compton scattering (ICS), require both transverse and longitudinal beam sizes on the order of tens of microns. Ultra-high density beams may be produced at moderate energy (50 MeV) by compression and subsequent strong focusing of low emittance, photoinjector sources. We describe the implementation of this method used at LLNL's PLEIADES ICS x-ray source in which the photoinjector-generated beam has been compressed to 300 fsec duration using the velocity bunching technique and focused to 20 μm rms size using an extremely high gradient, permanent magnet quadrupole (PMQ) focusing system.

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

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

Definition and measurement of the times-diffraction-limit number of high-power laser beams

Science.gov (United States)

Bollanti, Sarah; Di Lazzaro, Paolo; Murra, Daniele

1998-07-01

A novel definition of the times-diffraction-limit (TDL) number of a laser beam is given. A comparison is made with the commonly used beam-propagation parameter M2, which is unreliable for hard-edge beams, like those produced by unstable resonators with diffraction output coupling. The new suggested TDL number definition doesn't rely on the real beam comparison to a Gaussian beam, but on the comparison of the far-field performances of the real beam with respect to those of a uniphase beam with the same amplitude profile in the near field. A practical method is also given for the estimation of the TDL number of real beams. Finally, this procedure is applied to the high-peak-power laser beams generated by two excimer laser systems developed in ENEA.

Calculation of the non-inductive current profile in high-performance NSTX plasmas

Science.gov (United States)

Gerhardt, S. P.; Fredrickson, E.; Gates, D.; Kaye, S.; Menard, J.; Bell, M. G.; Bell, R. E.; Le Blanc, B. P.; Kugel, H.; Sabbagh, S. A.; Yuh, H.

2011-03-01

The constituents of the current profile have been computed for a wide range of high-performance plasmas in NSTX (Ono et al 2000 Nucl. Fusion 40 557); these include cases designed to maximize the non-inductive fraction, pulse length, toroidal-β or stored energy. In the absence of low-frequency MHD activity, good agreement is found between the reconstructed current profile and that predicted by summing the independently calculated inductive, pressure-driven and neutral beam currents, without the need to invoke any anomalous beam ion diffusion. Exceptions occur, for instance, when there are toroidal Alfvén eigenmode avalanches or coupled m/n = 1/1 + 2/1 kink-tearing modes. In these cases, the addition of a spatially and temporally dependent fast-ion diffusivity can reduce the core beam current drive, restoring agreement between the reconstructed profile and the summed constituents, as well as bringing better agreement between the simulated and measured neutron emission rate. An upper bound on the fast-ion diffusivity of ~0.5-1 m2 s-1 is found in 'MHD-free' discharges, based on the neutron emission, the time rate of change in the neutron signal when a neutral beam is stepped and reconstructed on-axis current density.

Calculation of the Non-Inductive Current Profile in High-Performance NSTX Plasmas

International Nuclear Information System (INIS)

Gerhardt, S.P.; Fredrickson, E.; Gates, D.; Kaye, S.; Menard, J.; Bell, M.G.; Bell, R.E.; Le Blanc, B.P.; Kugel, H.; Sabbagh, S.A.; Yuh, H.

2011-01-01

The constituents of the current profile have been computed for a wide range of high-performance plasmas in NSTX [M. Ono, et al., Nuclear Fusion 40, 557 (2000)]; these include cases designed to maximize the non-inductive fraction, pulse length, toroidal-β, or stored energy. In the absence of low-frequency MHD activity, good agreement is found between the reconstructed current profile and that predicted by summing the independently calculated inductive, pressure-driven, and neutral beam currents, without the need to invoke any anomalous beam ion diffusion. Exceptions occur, for instance, when there are toroidal Alfven eigenmode avalanches or coupled m/n=1/1+2/1 kink-tearing modes. In these cases, the addition of a spatially and temporally dependent fast ion diffusivity can reduce the core beam current drive, restoring agreement between the reconstructed profile and the summed constituents, as well as bringing better agreement between the simulated and measured neutron emission rate. An upper bound on the fast ion diffusivity of ∼0.5-1 m 2 /sec is found in 'MHD-free' discharges, based on the neutron emission, time rate of change of the neutron signal when a neutral beam is stepped, and reconstructed on-axis current density.

HIGH ENERGY DENSITY PHYSICS EXPERIMENTS WITH INTENSE HEAVY ION BEAMS

International Nuclear Information System (INIS)

Bieniosek, F.M.; Henestroza, E.; Leitner, M.; Logan, B.G.; More, R.M.; Roy, P.K.; Ni, P.; Seidl, P.A.; Waldron, W.L.; Barnard, J.J.

2008-01-01

The US heavy ion fusion science program has developed techniques for heating ion-beam-driven warm dense matter (WDM) targets. The WDM conditions are to be achieved by combined longitudinal and transverse space-charge neutralized drift compression of the ion beam to provide a hot spot on the target with a beam spot size of about 1 mm, and pulse length about 1-2 ns. As a technique for heating volumetric samples of matter to high energy density, intense beams of heavy ions are capable of delivering precise and uniform beam energy deposition dE/dx, in a relatively large sample size, and the ability to heat any solid-phase target material. Initial experiments use a 0.3 MeV K+ beam (below the Bragg peak) from the NDCX-I accelerator. Future plans include target experiments using the NDCX-II accelerator, which is designed to heat targets at the Bragg peak using a 3-6 MeV lithium ion beam. The range of the beams in solid matter targets is about 1 micron, which can be lengthened by using porous targets at reduced density. We have completed the fabrication of a new experimental target chamber facility for WDM experiments, and implemented initial target diagnostics to be used for the first target experiments in NDCX-1. The target chamber has been installed on the NDCX-I beamline. The target diagnostics include a fast multi-channel optical pyrometer, optical streak camera, VISAR, and high-speed gated cameras. Initial WDM experiments will heat targets by compressed NDCX-I beams and will explore measurement of temperature and other target parameters. Experiments are planned in areas such as dense electronegative targets, porous target homogenization and two-phase equation of state

Computational Calorimetry: High-Precision Calculation of Host–Guest Binding Thermodynamics

Science.gov (United States)

2015-01-01

We present a strategy for carrying out high-precision calculations of binding free energy and binding enthalpy values from molecular dynamics simulations with explicit solvent. The approach is used to calculate the thermodynamic profiles for binding of nine small molecule guests to either the cucurbit[7]uril (CB7) or β-cyclodextrin (βCD) host. For these systems, calculations using commodity hardware can yield binding free energy and binding enthalpy values with a precision of ∼0.5 kcal/mol (95% CI) in a matter of days. Crucially, the self-consistency of the approach is established by calculating the binding enthalpy directly, via end point potential energy calculations, and indirectly, via the temperature dependence of the binding free energy, i.e., by the van’t Hoff equation. Excellent agreement between the direct and van’t Hoff methods is demonstrated for both host–guest systems and an ion-pair model system for which particularly well-converged results are attainable. Additionally, we find that hydrogen mass repartitioning allows marked acceleration of the calculations with no discernible cost in precision or accuracy. Finally, we provide guidance for accurately assessing numerical uncertainty of the results in settings where complex correlations in the time series can pose challenges to statistical analysis. The routine nature and high precision of these binding calculations opens the possibility of including measured binding thermodynamics as target data in force field optimization so that simulations may be used to reliably interpret experimental data and guide molecular design. PMID:26523125

High-speed precision motion control

CERN Document Server

Yamaguchi, Takashi; Pang, Chee Khiang

2011-01-01

Written for researchers and postgraduate students in Control Engineering, as well as professionals in the Hard Disk Drive industry, this book discusses high-precision and fast servo controls in Hard Disk Drives (HDDs). The editors present a number of control algorithms that enable fast seeking and high precision positioning, and propose problems from commercial products, making the book valuable to researchers in HDDs. Each chapter is self contained, and progresses from concept to technique, present application examples that can be used within automotive, aerospace, aeronautical, and manufactu

High - speed steel for precise cased tools

International Nuclear Information System (INIS)

Karwiarz, J.; Mazur, A.

2001-01-01

The test results of high-vanadium high - speed steel (SWV9) for precise casted tools are presented. The face -milling cutters of NFCa80A type have been tested in industrial operating conditions. An average life - time of SWV9 steel tools was 3-10 times longer compare to the conventional high - speed milling cutters. Metallography of SWB9 precise casted steel revealed beneficial for tool properties distribution of primary vanadium carbides in the steel matrix. Presented results should be a good argument for wide application of high - vanadium high - speed steel for precise casted tools. (author)

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

Precision experiments with rare isotopes with LEBIT at MSU

Energy Technology Data Exchange (ETDEWEB)

Schury, P.; Bollen, G.; Ringle, R.; Sun, T. [National Superconducting Cyclotron Laboratory, East Lansing, MI (United States); Michigan State University, Department of Physics and Astronomy, East Lansing, MI (United States); Davies, D.A.; Morrissey, D.J. [National Superconducting Cyclotron Laboratory, East Lansing, MI (United States); Michigan State University, Department of Chemistry, East Lansing, MI (United States); Doemer, A.; Prinke, A. [Michigan State University, Department of Physics and Astronomy, East Lansing, MI (United States); Lawton, D.; Ottarson, J.; Schwarz, S.; Weissman, L. [National Superconducting Cyclotron Laboratory, East Lansing, MI (United States)

2005-09-01

The Low-Energy Beam and Ion Trap facility LEBIT at the NSCL is in the final phase of commissioning. Gas stopping of fast fragment beams and modern ion manipulation techniques are used to provide beams for high-precision mass measurements and other experiments. The status of the facility and the result of first test mass measurements on stable krypton isotopes are presented. (orig.)

A new high-speed X-ray beam chopper

International Nuclear Information System (INIS)

McPherson, A.; Wang, J.; Lee, P. L.; Mills, D. M.

1999-01-01

A new high-speed x-ray beam chopper using laser scanner technology has been developed and tested on the SRI-CAT sector 1 beamline at the Advanced Photon Source (APS) storage ring (1). As illustrated in figure 1, it is compact in size and has two sets of transmission windows: BK-7 glass for visible light transmission and 0.23-mm-thick Be for the transmission of x-rays. The rotor is made of aluminum and has a diameter of 50.8 mm. A 0.5-mm-wide and 2.29-mm-tall slit is cut through the center of the rotor. The circumference of the rotor has a coating of 1-mm-thick Ni, which gives an attenuation of 10 8 at 30 keV. Turning at nearly 80000 RPM, this beam chopper has an opening time window of 2450 ns, corresponding to 67% of the revolution time of the APS storage ring. The primary feature in selecting laser scanner technology to develop into an x-ray beam chopper was the high level of rotational speed control of the rotor that makes up the beam chopper element (2). By using an optical feedback circuit to sample the rotational speed four times each revolution, the jitter in the position of the transmission open time window is only 3 ns at the 3 standard deviation level. The APS storage ring orbital frequency, supplied by the control room, is divided down to provide the appropriate drive frequency for the beam chopper motor controller. By this means, both the storage ring and the beam chopper are operating off the same master clock. After a turn-on time of about 15 to 20 seconds, the rotational precision of the motor results in immediate phase locking to the temporal structure of the APS storage ring. By inserting a Stanford delay generator between the frequency divider and the beam chopper motor controller, the phase between the storage ring temporal structure and the beam chopper rotation can be adjusted to position the transmission time window of the beam chopper on any desired part of the storage ring fill pattern. If an asymmetric fill pattern is used in the APS storage

Precision improving of double beam shadow moiré interferometer by phase shifting interferometry for the stress of flexible substrate

Science.gov (United States)

Huang, Kuo-Ting; Chen, Hsi-Chao; Lin, Ssu-Fan; Lin, Ke-Ming; Syue, Hong-Ye

2012-09-01

While tin-doped indium oxide (ITO) has been extensively applied in flexible electronics, the problem of the residual stress has many obstacles to overcome. This study investigated the residual stress of flexible electronics by the double beam shadow moiré interferometer, and focused on the precision improvement with phase shifting interferometry (PSI). According to the out-of-plane displacement equation, the theoretical error depends on the grating pitch and the angle between incident light and CCD. The angle error could be reduced to 0.03% by the angle shift of 10° as a result of the double beam interferometer was a symmetrical system. But the experimental error of the double beam moiré interferometer still reached to 2.2% by the noise of the vibration and interferograms. In order to improve the measurement precision, PSI was introduced to the double shadow moiré interferometer. Wavefront phase was reconstructed by the five interferograms with the Hariharan algorithm. The measurement results of standard cylinder indicating the error could be reduced from 2.2% to less than 1% with PSI. The deformation of flexible electronic could be reconstructed fast and calculated the residual stress with the Stoney correction formula. This shadow moiré interferometer with PSI could improve the precision of residual stress for flexible electronics.

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)

The on-line beam control and diagnosis system of TARN

International Nuclear Information System (INIS)

Takanaka, M.; Watanabe, S.; Chiba, K.; Katayama, T.; Noda, A.

1982-04-01

The computer network in TARN is composed of a central main frame computer, two different minicomputers and several microprocessors. It has been used for the beam control and the beam diagnosis; support for adjustment of elements of the transport line and the ring, generation of RF voltage function, measurement of beam profile at RF stacking, on-line measurement of ν:value, and observation of Schottky signal. By the use of this computer system, the operation of TARN has been effectively and steadily performed, and additionally it has contributed to measuring the beam characteristics precisely in the ring. (author)

Study of a high power hydrogen beam diagnostic based on secondary electron emission

Energy Technology Data Exchange (ETDEWEB)

Sartori, E., E-mail: emanuele.sartori@igi.cnr.it [Consorzio RFX (CNR, ENEA, INFN, UNIPD, Acciaierie Venete SpA), Corso Stati Uniti 4, 35127 Padova (Italy); Department of Management and Engineering, University di Padova strad. S. Nicola 3, 36100 Vicenza (Italy); Panasenkov, A. [NRC, Kurchatov Institute, 1, Kurchatov Sq, Moscow 123182 (Russian Federation); Veltri, P. [Consorzio RFX (CNR, ENEA, INFN, UNIPD, Acciaierie Venete SpA), Corso Stati Uniti 4, 35127 Padova (Italy); INFN-LNL, viale dell’Università n. 2, 35020 Legnaro (Italy); Serianni, G.; Pasqualotto, R. [Consorzio RFX (CNR, ENEA, INFN, UNIPD, Acciaierie Venete SpA), Corso Stati Uniti 4, 35127 Padova (Italy)

2016-11-15

In high power neutral beams for fusion, beam uniformity is an important figure of merit. Knowing the transverse power profile is essential during the initial phases of beam source operation, such as those expected for the ITER heating neutral beam (HNB) test facility. To measure it a diagnostic technique is proposed, based on the collection of secondary electrons generated by beam-surface and beam-gas interactions, by an array of positively biased collectors placed behind the calorimeter tubes. This measurement showed in the IREK test stand good proportionality to the primary beam current. To investigate the diagnostic performances in different conditions, we developed a numerical model of secondary electron emission, induced by beam particle impact on the copper tubes, and reproducing the cascade of secondary emission caused by successive electron impacts. The model is first validated against IREK measurements. It is then applied to the HNB case, to assess the locality of the measurement, the proportionality to the beam current density, and the influence of beam plasma.