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Sample records for beam emittance measurement

  1. Beam emittance measurements on multicusp ion sources

    Energy Technology Data Exchange (ETDEWEB)

    Sarstedt, M.; Lee, Y.; Leung, K.N. [and others

    1995-08-01

    Multicusp ion sources are used for various applications. Presently, the implementation of this type of ion source planned for the development of an ion beam lithography machine, which will be used for the projection of sub-0.2 {mu}m patterns onto a wafer substrate. Since, for this application, a very good beam quality and a small ion energy spread are required, emittance measurements have been performed on a multicusp ion source for various source conditions. It is shown that the installation of proper capacitors between the extraction electrodes is necessary to avoid rf-pickup, which otherwise leads to a distortion of the beam emittance. The influence of the magnetic filter field on the beam emittance has been investigated, and the beam emittance of a dc filament-discharge plasma has also been compared to that of an rf-generated plasma.

  2. Beam emittance measurements on multicusp ion sources

    International Nuclear Information System (INIS)

    Sarstedt, M.; Lee, Y.; Leung, K.N.

    1995-08-01

    Multicusp ion sources are used for various applications. Presently, the implementation of this type of ion source planned for the development of an ion beam lithography machine, which will be used for the projection of sub-0.2 μm patterns onto a wafer substrate. Since, for this application, a very good beam quality and a small ion energy spread are required, emittance measurements have been performed on a multicusp ion source for various source conditions. It is shown that the installation of proper capacitors between the extraction electrodes is necessary to avoid rf-pickup, which otherwise leads to a distortion of the beam emittance. The influence of the magnetic filter field on the beam emittance has been investigated, and the beam emittance of a dc filament-discharge plasma has also been compared to that of an rf-generated plasma

  3. Measuring emittance using beam position monitors

    International Nuclear Information System (INIS)

    Russell, S.; Carlsten, B.

    1993-01-01

    The Los Alamos Advanced Free Electron Laser uses a high charge (greater than InC), low emittance (normalized rams emittance less than 5π mm mrad) photoinjector driven accelerator. The high brightness achieved is due, in large part, to the rapid acceleration of the electrons to relativistic velocities. As a result, the beam does not have time to thermalize its distribution and its universe profile is, in general, non-Gaussian. This, coupled with the very high brightness, makes it difficult to measure the transverse emittance. Techniques used must be able to withstand the rigors of very intense electron beams, and not be reliant on Gaussian assumptions. Beam position monitors are ideal for this. They are not susceptible to beam damage, and it has been shown previously that they can be used to measure the transverse emittance of a beam with a Gaussian profile. However, this Gaussian restriction is not necessary and, in fact, a transverse emittance measurement using beam position monitors is independent of the beam's distribution

  4. BEAM EMITTANCE MEASUREMENT TOOL FOR CEBAF OPERATIONS

    International Nuclear Information System (INIS)

    Chevtsov, Pavel; Tiefenback, Michael

    2008-01-01

    A new software tool was created at Jefferson Lab to measure the emittance of the CEBAF electron beams. The tool consists of device control and data analysis applications. The device control application handles the work of wire scanners and writes their measurement results as well as the information about accelerator settings during these measurements into wire scanner data files. The data analysis application reads these files and calculates the beam emittance on the basis of a wire scanner data processing model. Both applications are computer platform independent but are mostly used on LINUX PCs recently installed in the accelerator control room. The new tool significantly simplifies beam emittance measurement procedures for accelerator operations and contributes to a very high availability of the CEBAF machine for the nuclear physics program at Jefferson Lab.

  5. MEV Energy Electrostatic Accelerator Ion Beam Emittance Measurement

    OpenAIRE

    I.G. Ignat’ev; M.I. Zakharets; S.V. Kolinko; D.P. Shulha

    2014-01-01

    The testing equipment was designed, manufactured and tried out permitting measurements of total current, current profile and emittance of an ion beam extracted from the ion beam. MeV energy electrostatic accelerator ion H + beam emittance measurement results are presented.

  6. Shadow photography method for beam emittance measurement

    International Nuclear Information System (INIS)

    Kashkovskij, V.V.; Lisin, V.A.

    1988-01-01

    Improved technique of shadow photography which allows to measure rather simply and accurately the angular distribution of electrons extracted from betatron is described. Measurement accuracy of particle flight angles is determined by setting of rods relatively to the plane of photographic paper sheet, their diameter and shadow trace length. Incidental angle deviation of rod axes contributes mainly into the error. Mean root-square error constituted 2-3% according to the results of several measurements of angles

  7. A system for online beam emittance measurements and proton beam characterization

    Science.gov (United States)

    Nesteruk, K. P.; Auger, M.; Braccini, S.; Carzaniga, T. S.; Ereditato, A.; Scampoli, P.

    2018-01-01

    A system for online measurement of the transverse beam emittance was developed. It is named 4PrOBεaM (4-Profiler Online Beam Emittance Measurement) and was conceived to measure the emittance in a fast and efficient way using the multiple beam profiler method. The core of the system is constituted by four consecutive UniBEaM profilers, which are based on silica fibers passing across the beam. The 4PrOBεaM system was deployed for characterization studies of the 18 MeV proton beam produced by the IBA Cyclone 18 MeV cyclotron at Bern University Hospital (Inselspital). The machine serves daily radioisotope production and multi-disciplinary research, which is carried out with a specifically conceived Beam Transport Line (BTL). The transverse RMS beam emittance of the cyclotron was measured as a function of several machine parameters, such as the magnetic field, RF peak voltage, and azimuthal angle of the stripper. The beam emittance was also measured using the method based on the quadrupole strength variation. The results obtained with both techniques were compared and a good agreement was found. In order to characterize the longitudinal dynamics, the proton energy distribution was measured. For this purpose, a method was developed based on aluminum absorbers of different thicknesses, a UniBEaM detector, and a Faraday cup. The results were an input for a simulation of the BTL developed in the MAD-X software. This tool allows machine parameters to be tuned online and the beam characteristics to be optimized for specific applications.

  8. Emittance Measurements For Future LHC Beams Using The PS Booster Measurement Line

    CERN Document Server

    Abelleira, Jose; Mikulec, Bettina; Di Giovanni, Gian Piero; CERN. Geneva. ATS Department

    2017-01-01

    The CERN PS Booster measurement line contains three pairs of SEM grids separated by drift space that measures the beam size in both planes. The combined analysis of these grids allows calculating a value for the transverse beam emittances. The precision of such a measurement depends on the ratio of RMS beam size and wire spacing. Within the LIU-PSB upgrade the extraction kinetic energy of the PSB will be increased from the current 1.4 GeV to 2.0 GeV. This will result in smaller transverse beam sizes for some of the future beams. The present layout of the transverse emittance measurement line is reviewed to verify if it will satisfy future requirements.

  9. Simple emittance measurement of H- beams from a large plasma source

    International Nuclear Information System (INIS)

    Guharay, S.K.; Tsumori, K.; Hamabe, M.; Takeiri, Y.; Kaneko, O.; Kuroda, T.

    1996-03-01

    An emittance meter is developed using pepper-pot method. Kapton foils are used to detect intensity distributions of small beamlets at the 'image' plane of the pepper-pot. Emittance of H - beams from a large plasma source for the neutral beam injector of the Large Helical Device (LHD) has been measured. The normalized emittance (95%) of a 6 mA H - beam with emission current density of about 10 mA/cm 2 is ∼0.59 mm mrad. The present system is very simple, and it eliminates many complexities of the existing schemes. (author)

  10. Simple emittance measurement of H{sup -} beams from a large plasma source

    Energy Technology Data Exchange (ETDEWEB)

    Guharay, S.K.; Tsumori, K.; Hamabe, M.; Takeiri, Y.; Kaneko, O.; Kuroda, T.

    1996-03-01

    An emittance meter is developed using pepper-pot method. Kapton foils are used to detect intensity distributions of small beamlets at the `image` plane of the pepper-pot. Emittance of H{sup -} beams from a large plasma source for the neutral beam injector of the Large Helical Device (LHD) has been measured. The normalized emittance (95%) of a 6 mA H{sup -} beam with emission current density of about 10 mA/cm{sup 2} is {approx}0.59 mm mrad. The present system is very simple, and it eliminates many complexities of the existing schemes. (author).

  11. Simple emittance measurement of negative hydrogen ion beam using pepper-pot method

    Energy Technology Data Exchange (ETDEWEB)

    Hamabe, M.; Tsumori, K.; Takeiri, Y.; Kaneko, O.; Asano, E.; Kawamoto, T.; Kuroda, T. [National Inst. for Fusion Science, Nagoya (Japan); Guharay, S.K.

    1997-02-01

    A simple apparatus for emittance measurement using pepper-pot method is developed. The pepper-pot patterns are directly exposed and recorded on a Kapton foil. Using this apparatus, emittance was measured in the case of the negative hydrogen (H{sup -}) beam from the large negative ion source, which is the 1/3 scaled test device for the negative-ion-based neutral beam injection (N-NBI) on the Large Helical Device (LHD). As the consequence of the first trial, the 95% normalized emittance value is measured as 0.59 mm mrad. (author)

  12. Space Charge Correction on Emittance Measurement of Low Energy Electron Beams

    Energy Technology Data Exchange (ETDEWEB)

    Treado, Colleen J.; /Massachusetts U., Amherst

    2012-09-07

    The goal of any particle accelerator is to optimize the transport of a charged particle beam along a set path by confining the beam to a small region close to the design trajectory and directing it accurately along the beamline. To do so in the simplest fashion, accelerators use a system of magnets that exert approximately linear electromagnetic forces on the charged beam. These electromagnets bend the beam along the desired path, in the case of bending magnets, and constrain the beam to the desired area through alternating focusing and defocusing effects, in the case of quadrupole magnets. We can model the transport of such a beam through transfer matrices representing the actions of the various beamline elements. However, space charge effects, produced from self electric fields within the beam, defocus the beam and must be accounted for in the calculation of beam emittance. We present below the preliminary results of a MATLAB code built to model the transport of a charged particle beam through an accelerator and measure the emittance under the influence of space charge effects. We demonstrate the method of correctly calculating the emittance of a beam under space charge effects using a least square fit to determine the initial properties of the beam given the beam size measured at a specific point after transport.

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

    Science.gov (United States)

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

    2004-12-01

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

  14. Measurements of electron beam emittance in the Accelerator Test Facility damping ring operated in multibunch modes

    Directory of Open Access Journals (Sweden)

    Yosuke Honda

    2003-09-01

    Full Text Available We present the measurement results of electron beam emittance in the Accelerator Test Facility damping ring operated in multibunch modes. The measurements were carried out with an upgraded laser wire beam profile monitor. The monitor has now a vertical wire as well as a horizontal one and is able to make much faster measurements thanks to an increased effective laser power inside the cavity. The measured emittance shows no large bunch-to-bunch dependence in either the horizontal or vertical directions. The values of the vertical emittance are similar to those obtained in the single-bunch operation. The present results are an important step toward the realization of a high-energy linear collider.

  15. Multiwire secondary-emission monitor and the emittance measurement of the AGS beam

    International Nuclear Information System (INIS)

    Weng, W.T.; Chiang, I.H.; Smith, G.A.; Soukas, A.

    1983-01-01

    For CBA injection the transverse emittances and the Twiss parameters of the AGS beam have to be well defined to minimize the phase space dilution in CBA. Althoug there exists a profile monitor device at U165, there are three reasons why construction of multiwire profile monitor system at three locations from U500 to U168 is required: (1) the dispersion function is not zero at U165 which makes it harder to interpret the measurement; (2) the original single wire device takes five minutes to traverse the whole beam; (3) a three station multiwire system can provide the profile information at all locations in one pulse which makes on-line analysis possible. In summary, a set of three stations of Multiwire Secondary Emission Monitor (MSEM) has been built and installed in the fast external beam line for the measurement of beam profiles. Each unit consists of two planes each with 30 nickel wires having a diameter of 5 mils. The signal is linear within the range of 10 10 to 10 13 incident protons on the wire and the resolution of the signal is well within a few percent. A least-square fitting routine has been used to extract the emittance and phase space parameters of the beam. The emittances obtained at various intensities will help us to understand the AGS acceleration process and to choose the optimal injection scheme for CBA

  16. 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 ...

  17. Parametric emittance measurements of electron beams produced by a laser plasma accelerator

    Science.gov (United States)

    Barber, S. K.; van Tilborg, J.; Schroeder, C. B.; Lehe, R.; Tsai, H.-E.; Swanson, K. K.; Steinke, S.; Nakamura, K.; Geddes, C. G. R.; Benedetti, C.; Esarey, E.; Leemans, W. P.

    2018-05-01

    Laser plasma accelerators (LPA) offer an exciting possibility to deliver high energy, high brightness electrons beams in drastically smaller distance scales than is typical for conventional accelerators. As such, LPAs draw considerable attention as potential drivers for next generation light sources and for a compact linear collider. In order to asses the viability of an LPA source for a particular application, the brightness of the source should be properly characterized. In this paper, we present charge dependent transverse emittance measurements of LPA sources using both ionization injection and shock induced density down ramp injection, with the latter delivering smaller transverse emittances by a factor of two when controlling for charge density. The single shot emittance method is described in detail with a discussion on limitations related to second order transport effects. The direct role of space charge is explored through a series of simulations and found to be consistent with experimental observations.

  18. Beam emittance measurements in improving the energy resolution using an achromatic/dispersive system

    CERN Document Server

    Mohammadzadeh, A H; Afarideh, H; Haji-Saeid, S M; Aslani, G; 10.1016/S1350-4487(01)00270-0

    2002-01-01

    An achromatic/dispersive dual-purpose system is designed to transport the C-30 Cyclotron proton beam achromatically while it is capable of improving its energy resolution from 2*10/sup -2/ ( Delta E=600 keV) to about 10/sup -3/ ( Delta E=30 keV) at the Cyclotron Department, Nuclear Research Center for Agriculture and Medicine (NRCAM). A wire scanner was installed on the beam line to measure the proton beam profiles in both the transverse and longitudinal phase spaces. The beam matrix and its emittance were consequently deduced and used to find a satisfactory first-order solution to the problem using TRANSPORT code (Transport Appendix. Fermilab and CERN, Geneva, Switzerland, 1977). The necessary corrections to the second-order geometric and chromatic aberrations were incorporated by introducing sextupole components into the designed system as well as using TRANSPORT VARY CODE iteration method for further reduction of the induced aberrations. (8 refs).

  19. Beam phase space and emittance

    International Nuclear Information System (INIS)

    Buon, J.

    1990-12-01

    The classical and elementary results for canonical phase space, the Liouville theorem and the beam emittance are reviewed. Then, the importance of phase portraits to obtain a geometrical description of motion is emphasized, with examples in accelerator physics. Finally, a statistical point of view is used to define beam emittance, to study its law of approximate conservation and to treat two particular examples

  20. Application of activity pencil beam algorithm using measured distribution data of positron emitter nuclei for therapeutic SOBP proton beam

    International Nuclear Information System (INIS)

    Miyatake, Aya; Nishio, Teiji

    2013-01-01

    Purpose: Recently, much research on imaging the clinical proton-irradiated volume using positron emitter nuclei based on target nuclear fragment reaction has been carried out. The purpose of this study is to develop an activity pencil beam (APB) algorithm for a simulation system for proton-activated positron-emitting imaging in clinical proton therapy using spread-out Bragg peak (SOBP) beams.Methods: The target nuclei of activity distribution calculations are 12 C nuclei, 16 O nuclei, and 40 Ca nuclei, which are the main elements in a human body. Depth activity distributions with SOBP beam irradiations were obtained from the material information of ridge filter (RF) and depth activity distributions of compounds of the three target nuclei measured by BOLPs-RGp (beam ON-LINE PET system mounted on a rotating gantry port) with mono-energetic Bragg peak (MONO) beam irradiations. The calculated data of depth activity distributions with SOBP beam irradiations were sorted in terms of kind of nucleus, energy of proton beam, SOBP width, and thickness of fine degrader (FD), which were verified. The calculated depth activity distributions with SOBP beam irradiations were compared with the measured ones. APB kernels were made from the calculated depth activity distributions with SOBP beam irradiations to construct a simulation system using the APB algorithm for SOBP beams.Results: The depth activity distributions were prepared using the material information of RF and the measured depth activity distributions with MONO beam irradiations for clinical therapy using SOBP beams. With the SOBP width widening, the distal fall-offs of depth activity distributions and the difference from the depth dose distributions were large. The shapes of the calculated depth activity distributions nearly agreed with those of the measured ones upon comparison between the two. The APB kernels of SOBP beams were prepared by making use of the data on depth activity distributions with SOBP beam

  1. Emittance measurements at PITZ

    Energy Technology Data Exchange (ETDEWEB)

    Vashchenko, Grygorii; Asova, Galina; Baehr, Juergen; Grabosch, Hans Juergen; Hakobyan, Levon; Haenel, Marc; Ivanisenko, Yevgeniy; Khojoyan, Martin; Krasilnikov, Mikhail; Mahgoub, Mahmoud; Nozdrin, Mikhail; O' Shea, Brendon; Otevrel, Marek; Petrosyan, Bagrat; Richter, Dieter; Riemann, Sabine; Rimjaem, Sakhorn; Roensch, Juliane; Shapovalov, Andrey; Spesyvtsev, Roman; Staykov, Lazar; Stephan, Frank [DESY, 15738 Zeuthen (Germany); Floettmann, Klaus; Lederer, Sven; Schreiber, Siegfried [DESY, 22607 Hamburg (Germany); Klemz, Guido; Will, Ingo [Max-Born-Institute, Berlin(Germany)

    2010-07-01

    The Photo Injector Test facility at DESY, Zeuthen site, (PITZ) has an aim to develop and optimize high brightness electron sources for Free Electron Lasers like FLASH and the European XFEL. The new laser system allows to produce trains of laser pulses with flat-top temporal profiles of about 20 ps FWHM and rise/fall time of about 2 ps had been commissioned at PITZ in late autumn 2008. Photo electrons emitted from the Cs{sub 2}Te cathode are accelerated by a 1.6-cell L band RF gun cavity operated at 60 MV/m maximum accelerating gradient at the cathode. For measuring of transverse projected emittance the so called single slit scan technique is used at PITZ. This procedure is discussed. Recent results on measured emittance of electron beam are presented.

  2. Measurement techniques for low emittance tuning and beam dynamics at CESR

    Science.gov (United States)

    Billing, M. G.; Dobbins, J. A.; Forster, M. J.; Kreinick, D. L.; Meller, R. E.; Peterson, D. P.; Ramirez, G. A.; Rendina, M. C.; Rider, N. T.; Sagan, D. C.; Shanks, J.; Sikora, J. P.; Stedinger, M. G.; Strohman, C. R.; Williams, H. A.; Palmer, M. A.; Holtzapple, R. L.; Flanagan, J.

    2018-03-01

    After operating as a High Energy Physics electron-positron collider, the Cornell Electron-positron Storage Ring (CESR) has been converted to become a dedicated synchrotron light source for the Cornell High Energy Synchrotron Source (CHESS). Over the course of several years CESR was adapted for accelerator physics research as a test accelerator, capable of studying topics relevant to future damping rings, colliders and light sources. Initially some specific topics were targeted for accelerator physic research with the storage ring in this mode, labeled CesrTA. These topics included 1) tuning techniques to produce low emittance beams, 2) the study of electron cloud (EC) development in a storage ring and 3) intra-beam scattering effects. The complete conversion of CESR to CesrTA occurred over a several year period, described elsewhere [1–3]. A number of specific instruments were developed for CesrTA. Much of the pre-existing instrumentation was modified to accommodate the scope of these studies and these are described in a companion paper [4]. To complete this research, a number of procedures were developed or modified, often requiring coordinated measurements among different instruments [5]. This paper provides an overview of types of measurements employed for the study of beam dynamics during the operation of CesrTA.

  3. Beam phase space and emittance

    International Nuclear Information System (INIS)

    Buon, J.

    1992-02-01

    The classical and elementary results for canonical phase space, the Liouville theorem and the beam emittance are reviewed. Then, the importance of phase portraits to obtain a geometrical description of motion is emphasized, with examples in accelerator physics. Finally, a statistical point of view is used to define beam emittance, to study its law of approximate conservation, with three particular examples, and to introduce a beam envelope-ellipse and the β-function, emphasing the statistical features of its properties. (author) 14 refs.; 11 figs

  4. Single-shot measurements of low emittance beams from laser-plasma accelerators comparing two triggered injection methods

    Science.gov (United States)

    van Tilborg, Jeroen

    2017-10-01

    The success of laser plasma accelerator (LPA) based applications, such as a compact x-ray free electron laser (FEL), relies on the ability to produce electron beams with excellent 6D brightness, where brightness is defined as the ratio of charge to the product of the three normalized emittances. As such, parametric studies of the emittance of LPA generated electron beams are essential. Profiting from a stable and tunable LPA setup, combined with a carefully designed single-shot energy-dispersed emittance diagnostic, we present a direct comparison of charge dependent emittance measurements of electron beams generated by two different injection mechanisms: ionization injection and shock-induced density down-ramp injection. Both injection mechanisms have gained in popularity in recent years due to their demonstrated stable LPA performance. For the down-ramp injection configuration, normalized emittances a factor of two lower were recorded: less than 1 micron at spectral charge densities up to 2 pC/MeV. For both injection mechanisms, a contributing correlation of space charge to the emittance was identified. This measurement technique in general, and these results specifically, are critical to the evaluation of LPA injection methods and development of high-quality LPA beam lines worldwide. This work is supported by the U.S. DOE under Contract No. DE-AC02-05CH11231, by the U.S. DOE NNSA, DNN R&D (NA22), by the National Science Foundation under Grant No. PHY-1415596, and by the Gordon and Betty Moore Foundation under Grant ID GBMF4898.

  5. A High-Resolution Multi-Slit Phase Space Measurement Technique for Low-Emittance Beams

    Energy Technology Data Exchange (ETDEWEB)

    Thangaraj, J. C.T. [Fermilab; Piot, P. [Northern Illinois U.

    2012-07-25

    Precise measurement of transverse phase space of a high-brightness electron beamis of fundamental importance in modern accelerators and free-electron lasers. Often, the transverse phase space of a high-brightness, space-charge-dominated electron beam is measured using a multi-slit method. In this method, a transverse mask (slit/pepperpot) samples the beaminto a set of beamlets, which are then analyzed on to a screen downstream. The resolution in this method is limited by the type of screen used which is typically around 20 mum for a high-sensitivity Yttrium Aluminum Garnet screen. Accurate measurement of sub-micron transverse emittance using this method would require a long drift space between the multi-slit mask and observation screen. In this paper, we explore a variation of the technique that incorporates quadrupole magnets between the multi-slit mask and the screen. It is shown that this arrangement can improve the resolution of the transverse-phase-space measurement with in a short footprint.

  6. Development of Emittance Analysis Software for Ion Beam Characterization

    International Nuclear Information System (INIS)

    Padilla, M.J.; Liu, Yuan

    2007-01-01

    Transverse beam emittance is a crucial property of charged particle beams that describes their angular and spatial spread. It is a figure of merit frequently used to determine the quality of ion beams, the compatibility of an ion beam with a given beam transport system, and the ability to suppress neighboring isotopes at on-line mass separator facilities. Generally, a high-quality beam is characterized by a small emittance. In order to determine and improve the quality of ion beams used at the Holifield Radioactive Ion Beam Facility (HRIBF) for nuclear physics and nuclear astrophysics research, the emittances of the ion beams are measured at the off-line Ion Source Test Facilities. In this project, emittance analysis software was developed to perform various data processing tasks for noise reduction, to evaluate root-mean-square emittance, Twiss parameters, and area emittance of different beam fractions. The software also provides 2D and 3D graphical views of the emittance data, beam profiles, emittance contours, and RMS. Noise exclusion is essential for accurate determination of beam emittance values. A Self-Consistent, Unbiased Elliptical Exclusion (SCUBEEx) method is employed. Numerical data analysis techniques such as interpolation and nonlinear fitting are also incorporated into the software. The software will provide a simplified, fast tool for comprehensive emittance analysis. The main functions of the software package have been completed. In preliminary tests with experimental emittance data, the analysis results using the software were shown to be accurate

  7. Measuring emittances and sigma matrices

    International Nuclear Information System (INIS)

    Rees, J.; Rivkin, L.

    1984-03-01

    The method used for measuring emittance at the SLAC Linac and the linear collider damping ring is described. The basis of the method is derived using one two-by-two matrix to specify the state of the input beam (sigma matrix) and another to describe the lens-drift transport system (R-matrix)

  8. Laser based stripping system for measurement of the transverse emittance of H-beams at the CERN Linac4

    CERN Document Server

    Hofmann, T; Raich, U; Roncarolo, F; Cheymol, B

    2013-01-01

    The new LINAC4 at CERN will accelerate H- particles to 160 MeV and allow high brightness proton beam transfers to the Proton Synchrotron Booster, via a charge-exchange injection scheme. This paper describes the conceptual design of a laser system proposed for transverse profile and emittance measurements based on photon detachment of electrons from the H- ions. The binding energy of the outer electron is only 0.75 eV and can easily be stripped with a laser beam. Measuring the electron signal as function of the laser position allows the transverse beam profile to be reconstructed. A downstream dipole can also be used to separate the laser neutralized H0 atoms from the main H- beam. By imaging these H0 atoms as a function of laser position the transverse emittance can be reconstructed in the same way as in traditional slit-and-grid systems. By properly dimensioning the laser power and spot size, this method results in negligible beam losses and is therefore non-destructive. In addition, the absence of material ...

  9. Design of a control system for stepper motors with micro-metric precision employed in the beam emittance measurement of the Linac4 at CERN

    CERN Document Server

    AUTHOR|(CDS)2207212; Dueñas Díaz, José Antonio

    A new linear accelerator (Linac4) is being designed to replace its predecessor (Linac2) at CERN. The new Linac4 will double the initial intensity giving an injection energy of up to 160 MeV. It will be an essential component of the LHC (Large Hadron Collider). To assess the quality of the beam, monitoring systems are placed along the beam pipe, being one of them devoted to measure its emittance, the so-called emittance scanner. The measurement of the emittance is important since it constitutes one of the two main parameters that limits the overall LHC performance, being the other parameter the energy of the beam. While the energy level of the beam can be modified during different phases at CERN, the beam emittance cannot; it is determined by the first source that produces the beam. The beam emittance directly influences the amount of particles colliding. For this purpose, the Linac4 emittance scanner will be placed on the very first step of the whole CERN accelerator complex right after the particles sour...

  10. Detection and measurement of band-type electron beams on fixed section of convergent emitter system

    CERN Document Server

    Narkhinov, V P

    2002-01-01

    The method for determining the currents azimuthal uniformity of the radially convergent electron beams on the assigned transport length along the lines coinciding with the motion direction is proposed. The direct method for measuring the current distribution of twenty eight radially convergent electron beams is considered. The principle of action of the device developed on the Faraday cylinder basis and mounted in the coaxial system of the gas-discharge electron source is presented. The currents numerical evaluation indicated the relatively small scattering by amplitudes, not exceeding 5% with an account of the measurement error. The average density of the azimuthal electron current of 28 radially convergent beams constituted 10 sup - sup 5 A/cm sup 2

  11. Mass Measurements of an Electrospray Beam from a Single Emitter Ionic Liquid Ferrofluid Electrospray Source

    Data.gov (United States)

    National Aeronautics and Space Administration — The research that will be conducted in its broadest sense is experimentally measuring the electric field that is used in micro-scale propulsion devices. The key...

  12. Measurement of the transverse emittance for the NSC Pelletron

    International Nuclear Information System (INIS)

    Rodriques, G.; Mandal, A.; Chopra, S.; Joshi, R.; Datta, S.K.; Roy, A.

    1998-01-01

    The knowledge of the emittance (transverse and longitudinal) of the NSC pelletron is essential for matching the acceptance of the LINAC which is to be installed to augment the pelletron beam energies. The transverse emittance of NSC pelletron has been measured by employing a focussing element and a down-stream beam profile monitor

  13. Emittance measurements from the LLUMC proton accelerator

    International Nuclear Information System (INIS)

    Coutrakon, G.; Gillespie, G.H.; Hubbard, J.; Sanders, E.

    2005-01-01

    A new method of calculating beam emittances at the extraction point of a particle accelerator is presented. The technique uses the optimization programs NPSOL and MINOS developed at Stanford University in order to determine the initial values of beam size, divergence and correlation parameters (i.e. beam sigma matrix, σ ij ) that best fit measured beam parameters. These σ ij elements are then used to compute the Twiss parameters α, β, and the phase space area, ε, of the beam at the extraction point. Beam size measurements in X and Y throughout the transport line were input to the optimizer along with the magnetic elements of bends, quads, and drifts. The σ ij parameters were optimized at the accelerator's extraction point by finding the best agreement between these measured beam sizes and those predicted by TRANSPORT. This expands upon a previous study in which a 'trial and error' technique was used instead of the optimizer software, and which yielded similar results. The Particle Beam Optics Laboratory (PBO Lab TM ) program used for this paper integrates particle beam optics and other codes into a single intuitive graphically-based computing environment. This new software provides a seamless interface between the NPSOL and MINOS optimizer and TRANSPORT calculations. The results of these emittance searches are presented here for the eight clinical energies between 70 and 250 MeV currently being used at LLUMC

  14. Emittance growth of bunched beams in bends

    International Nuclear Information System (INIS)

    Carlsten, B.E.; Raubenheimer, T.O.

    1995-01-01

    Talman [Phys. Rev. Lett. 56, 1429 (1986)] has proposed a novel relativistic effect that occurs when a charged particle beam is bent in the magnetic field from an external dipole. The consequence of this effect is that the space-charge forces from the particles do not exhibit the usual inverse-square energy dependence and some part of them are, in fact, independent of energy. This led to speculation that this effect could introduce significant emittance growth for a bending electron beam. Subsequently, it was shown that this effect's influence on the beam's transverse motion is canceled for a dc beam by a potential depression within the beam (to first order in the beam radius divided by the bend radius). In this paper, we extend the analysis to include short bunch lengths (as compared to the beam pipe dimensions) and find that there is no longer the cancellation for forces both transverse to and in the direction of motion. We provide an estimate for the emittance growth as a function of bend angle, beam radius, and current, and for magnetic compression of an electron bunch

  15. Emittance measurements of FEL accelerators using optical transition radiation methods

    International Nuclear Information System (INIS)

    Fiorito, R.B.; Rule, D.W.; Lumpkin, A.H.; Tokar, R.L.; Dowell, D.H.; Sellyey, W.C.; Lowrey, A.R.

    1991-01-01

    Measurements of the emittance of the Boeing FEL accelerator operating at 107 Mev, were performed using optical transition radiation (OTR). The results of the three measurement methods: measurement of beam spot size as a function of magnetic quadrupole focusing strength, two screen beam spot measurements, and beam spot-divergence measurements using a OTR interferometer are compared and shown to be in excellent agreement

  16. Irreversible processes in beam emittance shaping at an ion source outlet

    International Nuclear Information System (INIS)

    Batalin, V.A.

    1984-01-01

    The value of the minimal possible emittance of ion beam extracted from gas-discharge source was estimated by the methods of nonequilibrium thermodynamics. Criterion for evaluation of ion optics quality and efficiency of beam formation in the system of ion extraction was obtained by correlation of mentioned value with beam emittance measured in the experiment

  17. Using television cameras to measure emittance

    International Nuclear Information System (INIS)

    Ross, M.

    1984-01-01

    Since the luminosity in a linear collider depends on the horizontal and vertical emittance (epsilon/sub x/, epsilon/sub y/) as 1/√(epsilon/sub x/epsilon/sub y/) a possible method for improving the performance would be to decrease one or both of these numbers. Once this has been done in a damping ring for example, great care must be taken to avoid effective emittance growth in the remainder of the collider. Therefore an effort should be made to measure epsilon, (x and y), as accurately as possible, both during machine development and operationally. One technique used for measuring epsilon is to insert a luminescent screen in the path of the beam and measure the size of the spot of light made as the beam passes with a television camera and some associated electronics. This has advantages over sampling type techniques (such as wire scanners) because it provides full pulse to pulse two-dimensional information

  18. Transverse emittance measurement at REGAE via a solenoid scan

    Energy Technology Data Exchange (ETDEWEB)

    Hachmann, Max

    2012-12-15

    The linear accelerator REGAE at DESY produces short and low charged electron bunches, on the one hand to resolve the excitation transitions of atoms temporally by pump probe electron diffraction experiments and on the other hand to investigate principal mechanisms of laser plasma acceleration. For both cases a high quality electron beam is required. A quantity to rate the beam quality is the beam emittance. In the course of this thesis transverse emittance measurements by a solenoid scan could be realized and beyond that an improved theoretical description of a solenoid was successful. The foundation of emittance measurements are constituted by theoretical models which describe the envelope of a beam. Two different models were derived. The first is an often used model to determine the transverse beam emittance without considering space charge effects. More interesting and challenging was the development of an envelope model taking space charge effects into account. It is introduced and cross checked with measurements and simulations.

  19. Studies on the nondestructive emittance measurement at a negative-hydrogen-ion beam; Untersuchungen zur zerstoerungsfreien Emittanzmessung an einem negativen Wasserstoffionenstrahl

    Energy Technology Data Exchange (ETDEWEB)

    Gabor, C.

    2007-07-01

    In the present thesis the already known idea to apply photodetechment for the diagnosis at a H{sup -} beam has be newly interpretated and improved. Thereby a nondestructive emittance measurement method was developed, which is especially suited for future high-current accelerator projects. For emittance measurements thereby mechanical components can be totally abandoned, if at a small part of the H{sup -} ions the additional with only 0.754 eV weak bound electron is separated by photodetachment {Dirac_h}{omega}+H{sup -}{yields}H{sup 0}+e{sup -}. The neutralized H{sup -} ions can be magnetically or electrostatically separated from the electrons and the remaining H{sup -} ions. Especially the neutral particles are offered by their insensitivity against external electromagnetic fields for the determination of the phase-space distribution of the ion beam. Also the momentum transfer by photodetechment can be neglected at the neutralized ions. The detection of the divergence angle has been pursued by a scintillator with a CCD camera. For the calculation of the number of neutralized particles a simplified model under assumption of homogeneous density distributions was developed. The aim of the approximation was to make statements about the requirement on the laser system and the detector. Thereby especially the suitability of the measurement for high beam currents and beam parameters, as they are typically present behind a RFQ. Further aspects like the influence of the angle between laser and ion beams, relativistic ion beam, as well as the position and angular resolution have been also object of the discussion.

  20. Transverse Emittance Measurement and Preservation at the LHC

    CERN Document Server

    AUTHOR|(CDS)2082907

    The Large Hadron Collider (LHC) at CERN is a high energy storage ring that provides proton and heavy ion collisions to study fundamental particle physics. The luminosity production is closely linked to emittance preservation in the accelerator. The transverse emittance is the phase space density of the beam and should be conserved when the particle beam is transformed through the accelerator. Perturbing effects, however, can lead to emittance increase and hence luminosity degradation. Measuring the emittance growth is a complex task with high intensity beams and changing energies. The machine optics and the transverse beam size have to be measured as accurately as possible. Beta function measurements with k-modulation will be discussed. With this method the quadrupole focussing strength is varied and the resulting tune change is traced to determine the beta function at the quadrupole. A new k-modulation measurement tool was developed for the LHC. The fully automatic and online measurement system takes constra...

  1. DIAGNOSIS OF THE LOW EMITTANCE BEAM IN ATF DR EXTRACTION LINE

    International Nuclear Information System (INIS)

    McCormick, Douglas

    2003-01-01

    The ATF (Accelerator Test Facility in KEK) damping ring has been designed to produce the low emittance beam required by future linear colliders. In the design, the normalized vertical emittance of the ATF damping ring is 3.0E-8 radm which corresponds to the vertical beam size of about 10 micron in the extraction line. The emittance of the beam extracted from the ATF damping ring is measured with four wire scanners located in a dispersion free region of the extraction line. The optics of the extraction line is also studied. We will report the method and the result of the emittance measurement at the extraction line

  2. Experimentally minimized beam emittance from an L-band photoinjector

    Directory of Open Access Journals (Sweden)

    M. Krasilnikov

    2012-10-01

    Full Text Available High brightness electron sources for linac based free-electron lasers (FELs are being developed at the Photo Injector Test facility at DESY, Zeuthen site (PITZ. Production of electron bunches with extremely small transverse emittance is the focus of the PITZ scientific program. The photoinjector optimization in 2008–2009 for a bunch charge of 1, 0.5, 0.25, and 0.1 nC resulted in measured emittance values which are beyond the requirements of the European XFEL [S. Rimjaem et al., Nucl. Instrum. Methods Phys. Res., Sect. A 671, 62 (2012NIMAER0168-900210.1016/j.nima.2011.12.101]. Several essential modifications were commissioned in 2010–2011 at PITZ, resulting in further improvement of the photoinjector performance. Significant improvement of the rf gun phase stability is a major contribution in the reduction of the measured transverse emittance. The old TESLA prototype booster was replaced by a new cut disk structure cavity. This allows acceleration of the electron beam to higher energies and supports much higher flexibility for stable booster operation as well as for longer rf pulses which is of vital importance especially for the emittance optimization of low charge bunches. The transverse phase space of the electron beam was optimized at PITZ for bunch charges in the range between 0.02 and 2 nC, where the quality of the beam measurements was preserved by utilizing long pulse train operation. The experimental optimization yielded worldwide unprecedented low normalized emittance beams in the whole charge range studied.

  3. Theory and measurements of emittance preservation in plasma wakefield acceleration

    Energy Technology Data Exchange (ETDEWEB)

    Frederico, Joel

    2016-12-01

    In this dissertation, we examine the preservation and measurement of emittance in the plasma wakefield acceleration blowout regime. Plasma wakefield acceleration (PWFA) is a revolutionary approach to accelerating charged particles that has been demonstrated to have the potential for gradients orders of magnitude greater than traditional approaches. The application of PWFA to the design of a linear collider will make new high energy physics research possible, but the design parameters must first be shown to be competitive with traditional methods. Emittance preservation is necessary in the design of a linear collider in order to maximize luminosity. We examine the conditions necessary for circular symmetry in the PWFA blowout regime, and demonstrate that current proposals meet these bounds. We also present an application of beam lamentation which describes the process of beam parameter and emittance matching. We show that the emittance growth saturates as a consequence of energy spread in the beam. The initial beam parameters determine the amount of emittance growth, while the contribution of energy spread is negligible. We also present a model for ion motion in the presence of a beam that is much more dense than the plasma. By combining the model of ion motion and emittance growth, we find the emittance growth due to ion motion is minimal in the case of marginal ion motion. In addition, we present a simulation that validates the ion motion model, which is under further development to examine emittance growth of both marginal and pronounced ion motion. Finally, we present a proof-of-concept of an emittance measurement which may enable the analysis of emittance preservation in future PWFA experiments.

  4. Nanometer emittance ultralow charge beams from rf photoinjectors

    Directory of Open Access Journals (Sweden)

    R. K. Li

    2012-09-01

    Full Text Available In this paper we discuss the generation of a new class of high brightness relativistic electron beams, characterized by ultralow charge (0.1–1 pC and ultralow normalized emittance (<50  nm. These beams are created in rf photoinjectors when the laser is focused on the cathode to very small transverse sizes (<30  μm rms. In this regime, the charge density at the cathode approaches the limit set by the extraction electric field. By shaping the laser pulse to have a cigarlike aspect ratio (the longitudinal dimension much larger than the transverse dimension and a parabolic temporal profile, the resulting space charge dominated dynamics creates a uniformly filled ellipsoidal distribution and the emittance can be nearly preserved to its thermal value. We also present a new method, based on a variation of the pepper-pot technique, for single shot measurements of the ultralow emittances for this new class of beams.

  5. Achievement of ultra-low emittance beam in the ATF damping ring

    CERN Document Server

    Honda, Y; Araki, S; Bane, Karl Leopold Freitag; Brachmann, A; Frisch, J; Fukuda, M; Hasegawa, K; Hayano, H; Hendrickson, L; Higashi, Y; Higo, T; Hirano, K; Hirose, T; Iida, K; Imai, T; Inoue, Y; Karataev, P; Kubo, K; Kurihara, Y; Kuriki, M; Kuroda, R; Kuroda, S; Luo, X; Matsuda, M; McCormick, D; Muto, T; Nakajima, K; Nelson, J; Nomura, M; Ohashi, A; Okugi, T; Omori, T; Ross, M; Sakai, H; Sakai, I; Sasao, N; Smith, S; Suzuki, T; Takano, M; Takashi, N; Taniguchi, T; Terunuma, N; Toge, N; Turner, J; Urakawa, J; Vogel, V; Wolski, A; Woodley, M; Yamazaki, I; Yamazaki, Y; Yocky, J; Young, A; Zimmermann, Frank

    2003-01-01

    We report on the smallest vertical emittance achieved in single-bunch-mode operation of the ATF. The emittances were measured with a laser-wire beam-profile monitor installed in the damping ring. The bunch length and the momentum spread of the beam were also recorded under the same conditions. The smallest vertical rms emittance measured is 4 pm in the limit of zero current. It increases by a factor of 1.5 for a bunch intensity of 10^10 electrons. There are no discrepancies between the measured data and the calculations of intra-beam scattering.

  6. Beam emittance reduction during operation of Indus-2

    Energy Technology Data Exchange (ETDEWEB)

    Fakhri, Ali Akbar, E-mail: fakhri@rrcat.gov.in; Kant, Pradeep; Ghodke, A. D.; Singh, Gurnam [Raja Ramanna Centre for Advanced Technology, Indore 452 013 (India)

    2015-11-15

    Indus-2 storage ring is a 2.5 GeV third generation synchrotron radiation source. This source was commissioned using a moderate optics. Beam injection was accomplished using an off momentum electron beam to avoid difficulties faced in storage of beam at 550 MeV. The injection procedure and relevant beam dynamical studies are discussed. The switch over from the moderate optics to low emittance optics is done at 2.5 GeV after storing the electron beam. The procedure evolved to reduce the beam emittance and its implementation during the operation is discussed.

  7. Innovative energy efficient low-voltage electron beam emitters

    International Nuclear Information System (INIS)

    Felis, Kenneth P.; Avnery, Tovi; Berejka, Anthony J.

    2002-01-01

    Advanced electron beams (AEB) has developed a modular, low voltage (80-125 keV), high beam current (up to 40 ma), electron emitter with typically 25 cm of beam width, that is housed in an evacuated, returnable chamber that is easy to plug in and connect. The latest in nanofabrication enables AEB to use an ultra-thin beam window. The power supply for AEB's emitter is based on solid-state electronics. This combination of features results in a remarkable electrical efficiency. AEB's electron emitter relies on a touch screen, computer control system. With 80 μm of unit density beam penetration, AEB's electron emitter has gained market acceptance in the curing of opaque, pigmented inks and coatings used on flexible substrates, metals and fiber composites and in the curing of adhesives in foil based laminates

  8. Innovative energy efficient low-voltage electron beam emitters

    Science.gov (United States)

    Felis, Kenneth P.; Avnery, Tovi; Berejka, Anthony J.

    2002-03-01

    Advanced electron beams (AEB) has developed a modular, low voltage (80-125 keV), high beam current (up to 40 ma), electron emitter with typically 25 cm of beam width, that is housed in an evacuated, returnable chamber that is easy to plug in and connect. The latest in nanofabrication enables AEB to use an ultra-thin beam window. The power supply for AEB's emitter is based on solid-state electronics. This combination of features results in a remarkable electrical efficiency. AEB's electron emitter relies on a touch screen, computer control system. With 80 μm of unit density beam penetration, AEB's electron emitter has gained market acceptance in the curing of opaque, pigmented inks and coatings used on flexible substrates, metals and fiber composites and in the curing of adhesives in foil based laminates.

  9. Demonstration of cathode emittance dominated high bunch charge beams in a DC gun-based photoinjector

    Science.gov (United States)

    Gulliford, Colwyn; Bartnik, Adam; Bazarov, Ivan; Dunham, Bruce; Cultrera, Luca

    2015-03-01

    We present the results of transverse emittance and longitudinal current profile measurements of high bunch charge (≥100 pC) beams produced in the DC gun-based Cornell energy recovery linac photoinjector. In particular, we show that the cathode thermal and core beam emittances dominate the final 95% and core emittances measured at 9-9.5 MeV. Additionally, we demonstrate excellent agreement between optimized 3D space charge simulations and measurement, and show that the quality of the transverse laser distribution limits the optimal simulated and measured emittances. These results, previously thought achievable only with RF guns, demonstrate that DC gun based photoinjectors are capable of delivering beams with sufficient single bunch charge and beam quality suitable for many current and next generation accelerator projects such as Energy Recovery Linacs and Free Electron Lasers.

  10. Demonstration of cathode emittance dominated high bunch charge beams in a DC gun-based photoinjector

    Energy Technology Data Exchange (ETDEWEB)

    Gulliford, Colwyn, E-mail: cg248@cornell.edu; Bartnik, Adam, E-mail: acb20@cornell.edu; Bazarov, Ivan; Dunham, Bruce; Cultrera, Luca [CLASSE, Cornell University, 161 Synchrotron Drive Ithaca, New York 14853-8001 (United States)

    2015-03-02

    We present the results of transverse emittance and longitudinal current profile measurements of high bunch charge (≥100 pC) beams produced in the DC gun-based Cornell energy recovery linac photoinjector. In particular, we show that the cathode thermal and core beam emittances dominate the final 95% and core emittances measured at 9–9.5 MeV. Additionally, we demonstrate excellent agreement between optimized 3D space charge simulations and measurement, and show that the quality of the transverse laser distribution limits the optimal simulated and measured emittances. These results, previously thought achievable only with RF guns, demonstrate that DC gun based photoinjectors are capable of delivering beams with sufficient single bunch charge and beam quality suitable for many current and next generation accelerator projects such as Energy Recovery Linacs and Free Electron Lasers.

  11. Transverse emittance measurement and preservation at the LHC

    Energy Technology Data Exchange (ETDEWEB)

    Kuhn, Maria

    2016-06-20

    The Large Hadron Collider (LHC) at CERN is a high energy storage ring that provides proton and heavy ion collisions to study fundamental particle physics. The luminosity production is closely linked to emittance preservation in the accelerator. The transverse emittance is the phase space density of the beam and should be conserved when the particle beam is transformed through the accelerator. Perturbing effects, however, can lead to emittance increase and hence luminosity degradation. Measuring the emittance growth is a complex task with high intensity beams and changing energies. The machine optics and the transverse beam size have to be measured as accurately as possible. Beta function measurements with k-modulation are discussed. With this method the quadrupole focussing strength is varied and the resulting tune change is traced to determine the beta function at the quadrupole. A new k-modulation measurement tool was developed for the LHC. The fully automatic and online measurement system takes constraints of various systems such as tune measurement precision and powering limitations of the LHC superconducting circuits into account. With sinusoidal k-modulation record low beta function measurement uncertainties in the LHC have been reached. 2015 LHC beta function and β*, which is the beta function at the collision point, measurements with k-modulation will be presented. Wire scanners and synchrotron light monitors are presently used in the LHC to measure the transverse beam size. Accuracy and limitations of the LHC transverse profile monitors are discussed. During the 2012 LHC proton run it was found that wire scanner photomultiplier saturation added significant uncertainty on all measurements. A large discrepancy between emittances from wire scanners and luminosity was discovered but not solved. During Long Shutdown 1 the wire scanner system was upgraded with new photomultipliers. A thorough study of LHC wire scanner measurement precision in 2015 is presented

  12. Feasibility study for the measurement of the longitudinal emittance of the beam in the mean energy line of the Spiral-2 accelerator; Etude de faisabilite pour la mesure de l'emittance longitudinale du faisceau dans la ligne moyenne energie de l'accelerateur primaire Spiral-2

    Energy Technology Data Exchange (ETDEWEB)

    Duperrier, R.; Uriot, D

    2006-09-15

    The author describes 3 methods for measuring beam longitudinal emittance and presents the equipment and conditions required for the measurement. The first method implies to make the phase space discrete through a set of slits coupled to a dipole and to make a measurement of the phase extension. The second method is the 3 gradients method that is based on the measurement of different packet phase extensions that are obtained through the variation of the electric field amplitude of the first beam buncher of the mean energy line. The third method consists in simulating the beam transport through the use of simulation codes and the measurement of phase extension and transverse beam emittances. The third method appears to be complementary to the first one when non-linearities in transport are no more negligible. (A.C.)

  13. Low emittance electron beam formation with a 17 GHz RF gun

    Directory of Open Access Journals (Sweden)

    W. J. Brown

    2001-08-01

    Full Text Available We report on electron beam quality measurement results from the Massachusetts Institute of Technology 17 GHz RF gun experiment. The 1.5 cell RF gun uses a solenoid for emittance compensation. It has produced bunch charges up to 0.1 nC with beam energies up to 1 MeV. The normalized rms emittance of the beam after 35 cm of transport from the gun has been measured by a slit technique to be 3π mm mrad for a 50 pC bunch. This agrees well with PARMELA simulations at these beam energies. At the exit of the electron gun, we estimate the emittance to be about 1π mm mrad, which corresponds to a beam brightness of about 80 A/(π mm mrad^{2}. Improved beam quality should be possible with a higher energy output electron beam from the gun.

  14. Emittance and beam size distortion due to linear coupling

    International Nuclear Information System (INIS)

    Parzen, G.

    1993-01-01

    At injection, the presence of linear coupling may result in an increased beam emittance and in increased beam dimensions. Results for the emittance in the presence of linear coupling will be found. These results for the emittance distortion show that the harmonics of the skew quadrupole field close to ν x + ν y are the important harmonics. Results will be found for the important driving terms for the emittance distortion. It will be shown that if these driving terms are corrected, then the total emittance is unchanged, var-epsilon x + var-epsilon y = var-epsilon 1 + var-epsilon 2 . Also, the increase in the beam dimensions will be limited to a factor which is less than 1.414. If the correction is good enough, see below for details, one can achieve var-epsilon 1 = var-epsilon x , var-epsilon 2 = var-epsilon where var-epsilon 1 , var-epsilon 2 are the emittances in the presence of coupling, and the beam dimensions are unchanged. Global correction of the emittance and beam size distortion appears possible

  15. 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

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

    Science.gov (United States)

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

    1991-05-01

    A visual diagnostic technique was 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).

  17. Emittance measurements at the Darmstadt source of polarized electrons

    Energy Technology Data Exchange (ETDEWEB)

    Ingenhaag, Christoph; Barday, Roman; Eckardt, Christian; Enders, Joachim; Goeoek, Alf; Poltoratska, Yuliya; Wagner, Markus [Institut fuer Kernphysik, Technische Universitaet, Darmstadt (Germany)

    2009-07-01

    Emittance measurements for low-energy (100 keV) electron beams are presented. Data was acquired at the teststand of the source of polarized electrons which is being developed for future implementation at the superconducting Darmstadt electron linear accelerator S-DALINAC. Polarized electrons are produced by laser irradiation of a strained-superlattice GaAs cathode. The emittance was determined by measuring the beam profile as a function of the focusing strength of a solenoid for various operation modes (intensity, laser spot size, laser wavelength, pulsed vs. DC laser operation) of the electron source.

  18. Ultra low emittance electron beams from multi-alkali antimonide photocathode operated with infrared light

    Science.gov (United States)

    Cultrera, L.; Gulliford, C.; Bartnik, A.; Lee, H.; Bazarov, I.

    2016-03-01

    The intrinsic emittance of electron beams generated from a multi-alkali photocathode operated in a high voltage DC gun is reported. The photocathode showed sensitivity extending to the infrared part of the spectrum up to 830 nm. The measured intrinsic emittances of electron beams generated with light having wavelength longer than 800 nm are approaching the limit imposed by the thermal energy of electrons at room temperature with quantum efficiencies comparable to metallic photocathodes used in operation of modern photoinjectors.

  19. Emittance Measurement for Beamline Extension at the PET Cyclotron

    Directory of Open Access Journals (Sweden)

    Sae-Hoon Park

    2016-01-01

    Full Text Available Particle-induced X-ray emission is used for determining the elemental composition of materials. This method uses low-energy protons (of several MeV, which can be obtained from high-energy (of tens MeV accelerators. Instead of manufacturing an accelerator for generating the MeV protons, the use of a PET cyclotron has been suggested for designing the beamline for multipurpose applications, especially for the PIXE experiment, which has a dedicated high-energy (of tens MeV accelerator. The beam properties of the cyclotron were determined at this experimental facility by using an external beamline before transferring the ion beam to the experimental chamber. We measured the beam profile and calculated the emittance using the pepper-pot method. The beam profile was measured as the beam current using a wire scanner, and the emittance was measured as the beam distribution at the beam dump using a radiochromic film. We analyzed the measurement results and are planning to use the results obtained in the simulations of external beamline and aligned beamline components. We will consider energy degradation after computing the beamline simulation. The experimental study focused on measuring the emittance from the cyclotron, and the results of this study are presented in this paper.

  20. Limits to Electron Beam Emittance from Stochastic Coulomb Interactions

    Energy Technology Data Exchange (ETDEWEB)

    Coleman-Smith, Christopher; Padmore, Howard A.; Wan, Weishi

    2008-08-22

    Dense electron beams can now be generated on an ultrafast timescale using laser driven photo-cathodes and these are used for a range of applications from ultrafast electron defraction to free electron lasers. Here we determine a lower bound to the emittance of an electron beam limited by fundamental stochastic Coulomb interactions.

  1. 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

  2. Multi-dimensional beam emittance and β-functions

    International Nuclear Information System (INIS)

    Buon, J.

    1993-05-01

    The concept of r.m.s. emittance is extended to the case of several degrees of freedom that are coupled. That multi-dimensional emittance is lower than the product of the emittances attached to each degree of freedom, but is conserved in a linear motion. An envelope-hyperellipsoid is introduced to define the β-functions of the beam envelope. On the contrary of an one-degree of freedom motion, it is emphasized that these envelope functions differ from the amplitude functions of the normal modes of motion as a result of the difference between the Liouville and Lagrange invariants. (author) 4 refs

  3. Emittance characteristics of negative ion beams generated by the sputter technique

    International Nuclear Information System (INIS)

    Alton, G.D.

    1989-01-01

    Average emittance data for ion beams extracted from cesium-sputter negative ion sources equipped with spherical, ellipsoidal, and cylindrical geometry cesium-surface ionizers are presented. The attributes of the respective source geometries are described in terms of their cesium ion optical properties. The results of recent measurement of the emittances of momentum-analyzed beams extracted from the ellipsoidal geometry source are also presented. These measurements indicate the presence of a species-dependent effect. The effect is believed to be attributable to differences in the energy spreads of the respective negative ion beams introduced by the sputter generation process. 11 refs., 8 figs

  4. Wire scanner data analysis for the SSC Linac emittance measurement

    International Nuclear Information System (INIS)

    Yao, C.Y.; Hurd, J.W.; Sage, J.

    1993-07-01

    The wire scanners are designed in the SSC Linac for measurement of beam emittance at various locations. In order to obtain beam parameters from the scan signal, a data analysis program was developed that considers the problems of noise reduction, machine modeling, parameter fitting, and correction. This program is intended as a tool for Linac commissioning and also as part of the Linac control program. Some of the results from commissioning runs are presented

  5. The emittance of high current heavy ion beams

    International Nuclear Information System (INIS)

    White, N.R.; Devaney, A.S.

    1989-01-01

    Ion implantation is the main application for high current heavy ion beams. Transfer ratio is defined as the ratio of the total ion current leaving the ion source to the current delivered to the endstation. This ratio is monitored and logged and its importance is explained. It is also affected by other factors, such as the isotopic and molecular composition of the total ion beam. The transfer ratio reveals the fraction of ions which are intercepted by parts of the beamline system. The effects of these ions are discussed in two categories: processing purity and reliability. In discussing the emittance of ribbon beams, the two orthogonal planes are usually considered separately. Longitudinal emittance is determined by slot length and by plasma ion temperature. It has already been revealed that the longitudinal divergence of the beams from BF3 is perhaps double that of the beam from arsenic vapour or argon, at the same total perveance from the ion source. This poses the question: why is the ion temperature higher for BF3 than for As or Ar? The transverse emittance is in practical terms dominated by the divergence. It is the most fruitful area for improvement in most real-world systems. There is an intrinsic divergence arising from initial ion energies within the plasma, and there is emittance growth that can occur as a result of aberration in the beam extraction optics. (N.K.)

  6. 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...

  7. Model of emittance growth in a self-pinched beam

    International Nuclear Information System (INIS)

    Lee, E.P.; Yu, S.S.

    1979-01-01

    A semi-phenomenological formula is proposed for the change of emittance of a self-pinched beam which is not matched to its equilibrium radius. Near equilibrium this formula, coupled with an envelope equation, yields the damped sausage oscillations observed in simulation and experiments. For a beam which is injected cold (no transverse velocity spread), the formula coincides with the analytically calculated initial growth of emittance. The basic theory is developed here and used to compute the linear damping rate for several current profiles. The resultant non-linear increase in equilibrium quantities is also calculated in lowest order of the degree of mismatch

  8. Emittance Measurements from a Laser Driven Electron Injector

    Energy Technology Data Exchange (ETDEWEB)

    Reis, David A

    2003-07-28

    The Gun Test Facility (GTF) at the Stanford Linear Accelerator Center was constructed to develop an appropriate electron beam suitable for driving a short wavelength free electron laser (FEL) such as the proposed Linac Coherent Light Source (LCLS). For operation at a wavelength of 1.5 {angstrom}, the LCLS requires an electron injector that can produce an electron beam with approximately 1 {pi} mm-mrad normalized rms emittance with at least 1 nC of charge in a 10 ps or shorter bunch. The GTF consists of a photocathode rf gun, emittance-compensation solenoid, 3 m linear accelerator (linac), drive laser, and diagnostics to measure the beam. The rf gun is a symmetrized 1.6 cell, s-band high gradient, room temperature, photocathode structure. Simulations show that this gun when driven by a temporally and spatially shaped drive laser, appropriately focused with the solenoid, and further accelerated in linac can produce a beam that meets the LCLS requirements. This thesis describes the initial characterization of the laser and electron beam at the GTF. A convolved measurement of the relative timing between the laser and the rf phase in the gun shows that the jitter is less than 2.5 ps rms. Emittance measurements of the electron beam at 35 MeV are reported as a function of the (Gaussian) pulse length and transverse profile of the laser as well as the charge of the electron beam at constant phase and gradient in both the gun and linac. At 1 nC the emittance was found to be {approx} 13 {pi} mm-mrad for 5 ps and 8 ps long laser pulses. At 0.5 nC the measured emittance decreased approximately 20% in the 5 ps case and 40% in the 8 ps case. These measurements are between 40-80% higher than simulations for similar experimental conditions. In addition, the thermal emittance of the electron beam was measured to be 0.5 {pi} mm-mrad.

  9. Emittance preservation during bunch compression with a magnetized beam

    Energy Technology Data Exchange (ETDEWEB)

    Stratakis, Diktys [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2015-09-02

    The deleterious effects of coherent synchrotron radiation (CSR) on the phase-space and energy spread of high-energy beams in accelerator light sources can significantly constrain the machine design and performance. In this paper, we present a simple method to preserve the beam emittance by means of using magnetized beams that exhibit a large aspect ratio on their transverse dimensions. The concept is based on combining a finite solenoid field where the beam is generated together with a special optics adapter. Numerical simulations of this new type of beam source show that the induced phase-space density growth can be notably suppressed to less than 1% for any bunch charge. This work elucidates the key parameters that are needed for emittance preservation, such as the required field and aspect ratio for a given bunch charge.

  10. Emittance of secondary beams and the project SISSI

    International Nuclear Information System (INIS)

    Mittig, W.

    1990-01-01

    The study of exotic nuclei has become a very active domain at GANIL. These nuclei are produced by a fragmentation-like process, which gives products focused to forward angles and having a rather well determined velocity. With the spectrometers actually used for studying these nuclei, LISE [1] and SPEG [2], only about typically 1% of the reaction products are accepted by these devices. In order to increase the collection efficiency, the author considers these products as a secondary beam. The Liouville theorem states that the emittance is conserved during beam transport, and the cost and difficulty of construction of this beam line increase with the emittance. Decision on the construction will be taken in beginning of 1990, and if accepted will increase the collection efficiency at GANIL by one order of magnitude. It will produce low emittance secondary beams, and increase the experimental flexibility due to the fact that this device will be placed up stream the experimental area, thus this beam may be sent to all existing equipment

  11. Measurements of Thermal Emittance for Cesium Telluride Photocathodes at PITZ

    CERN Document Server

    Miltchev, V; Grabosch, H J; Han, J H; Krasilnikov, M; Oppelt, A; Petrosian, B; Staykov, L; Stephan, F

    2005-01-01

    The thermal emittance determines the lower emittance limit and its measurement is of high importance to understand the ultimate injector performance. In this contribution we present results of thermal emittance measurements under rf operation conditions for various Cs2Te cathodes and different accelerating gradients. Measurements of thermal emittance scaling with the cathode laser spot size are presented and analysed. The significance of the Schottky effect in the emittance formation process is discussed.

  12. Ultra low emittance electron beams from multi-alkali antimonide photocathode operated with infrared light

    Energy Technology Data Exchange (ETDEWEB)

    Cultrera, L.; Gulliford, C.; Bartnik, A.; Lee, H.; Bazarov, I. [Cornell Laboratory for Accelerator-Based Sciences and Education, Cornell University, Ithaca, New York 14853 (United States)

    2016-03-28

    The intrinsic emittance of electron beams generated from a multi-alkali photocathode operated in a high voltage DC gun is reported. The photocathode showed sensitivity extending to the infrared part of the spectrum up to 830 nm. The measured intrinsic emittances of electron beams generated with light having wavelength longer than 800 nm are approaching the limit imposed by the thermal energy of electrons at room temperature with quantum efficiencies comparable to metallic photocathodes used in operation of modern photoinjectors.

  13. The Brookhaven ATF low-emittance beam line

    International Nuclear Information System (INIS)

    Wang, X.J.; Kirk, H.G.

    1991-01-01

    One component of the experimental program at the Brookhaven Accelerator Test Facility (ATF) consists of a class of experiments which will study the acceleration of electrons through micron-size structures which are exposed in coincidence to a 100 GW CO 2 laser beam. These experiments require the development and control of an electron beam with geometric emittances on the order of 10 -10 m-rad and intensities on the order of 10 6 electrons. In this paper, the authors describe the strategies for producing such beams and the effects of higher-order aberrations. Particle tracking results are presented for the final-focus system

  14. Emittance growth due to space charge compensation and beam intensity instabilities in negative ion beams

    Directory of Open Access Journals (Sweden)

    C. A. Valerio-Lizarraga

    2018-03-01

    Full Text Available The need to extract the maximum beam intensity with low transversal emittance often comes with the drawback of operating the ion source to limits where beam current instabilities arise, such fluctuations can change the beam properties producing a mismatch in the following sections of the machine. The space charge compensation (SCC generated by the beam particles colliding with the residual gas reaches a steady state after a build-up time. This paper shows how once in the steady state, the beam ends with a transversal emittance value bigger than the case without compensation. In addition, we study how the beam intensity variation can disturb the SCC dynamics and its impact on the beam properties. The results presented in this work come from 3-D simulations using tracking codes taking into account the secondary ions to estimate the degree of the emittance growth due to space charge and SCC.

  15. Emittance growth due to space charge compensation and beam intensity instabilities in negative ion beams

    Science.gov (United States)

    Valerio-Lizarraga, C. A.

    2018-03-01

    The need to extract the maximum beam intensity with low transversal emittance often comes with the drawback of operating the ion source to limits where beam current instabilities arise, such fluctuations can change the beam properties producing a mismatch in the following sections of the machine. The space charge compensation (SCC) generated by the beam particles colliding with the residual gas reaches a steady state after a build-up time. This paper shows how once in the steady state, the beam ends with a transversal emittance value bigger than the case without compensation. In addition, we study how the beam intensity variation can disturb the SCC dynamics and its impact on the beam properties. The results presented in this work come from 3-D simulations using tracking codes taking into account the secondary ions to estimate the degree of the emittance growth due to space charge and SCC.

  16. Superconducting wiggler magnets for beam-emittance damping rings

    CERN Document Server

    Schoerling, Daniel

    2012-01-01

    Ultra-low emittance beams with a high bunch charge are necessary for the luminosity performance of linear electron-positron colliders, such as the Compact Linear Collider (CLIC). An effective way to create ultra-low emittance beams with a high bunch charge is to use damping rings, or storage rings equipped with strong damping wiggler magnets. The remanent field of the permanent magnet materials and the ohmic losses in normal conductors limit the economically achievable pole field in accelerator magnets operated at around room temperature to below the magnetic saturation induction, which is 2.15 T for iron. In wiggler magnets, the pole field in the center of the gap is reduced further like the hyperbolic cosine of the ratio of the gap size and the period length multiplied by pi. Moreover, damping wiggler magnets require relatively large gaps because they have to accept the un-damped beam and to generate, at a small period length, a large magnetic flux density amplitude to effectively damp the beam emittance....

  17. Measurements of intrinsic emittance dependence on rf field for copper photocathodes

    Directory of Open Access Journals (Sweden)

    Eduard Prat

    2015-06-01

    Full Text Available Radio-frequency (rf photoinjectors are used to generate high-brightness electron beams for a wide range of applications. Because of their outstanding beam quality, they are particularly well-suited as sources for X-ray free-electron lasers (FELs. The beam emittance, which is significantly influenced by the intrinsic emittance of the cathode, is fundamental for FELs, since it has a strong impact on the lasing performance and it defines the length and cost of the facility. In this paper we present measurements of the intrinsic emittance as a function of the rf field for a copper photocathode. Our measurements match with the theoretical expectations, showing that the intrinsic emittance can be reduced by decreasing the rf field at the cathode. We obtained normalized intrinsic emittances down to 350  nm/mm, the lowest values ever measured in a rf photoinjector.

  18. Dependence of simulated positron emitter yields in ion beam cancer therapy on modeling nuclear fragmentation

    DEFF Research Database (Denmark)

    Lühr, Armin; Priegnitz, Marlen; Fiedler, Fine

    2014-01-01

    In ion beam cancer therapy, range verification in patients using positron emission tomography (PET) requires the comparison of measured with simulated positron emitter yields. We found that (1) changes in modeling nuclear interactions strongly affected the positron emitter yields and that (2) Monte...... Carlo simulations with SHIELD-HIT10A reasonably matched the most abundant PET isotopes 11C and 15O. We observed an ion-energy (i.e., depth) dependence of the agreement between SHIELD-HIT10A and measurement. Improved modeling requires more accurate measurements of cross-section values....

  19. Low Emittance Guns for the ILC Polarized Electron Beam

    International Nuclear Information System (INIS)

    Clendenin, J. E.; Brachmann, A.; Ioakeimidi, K.; Kirby, R. E.; Maruyama, T.; Miller, R. H.; Wang, J. W.; Zhou, F.

    2007-01-01

    Polarized electron beams generated by DC guns are routinely available at several accelerators including JLAB, Mainz and SLAC. These guns operate with a cathode bias on the order of -100 kV. To minimize space charge effects, relatively long bunches are generated at the gun and then compressed longitudinally external to the gun just before and during initial acceleration. For linear colliders, this compression is accomplished using a combination of rf bunchers. For the basic design of the International Linear Collider (ILC), a 120 kV DC photocathode gun is used to produce a series of nanosecond bunches that are each compressed by two sub-harmonic bunchers (SHBs) followed by an L-band buncher and capture section. The longitudinal bunching process results in a significantly higher emittance than produced by the gun alone. While high-energy experiments using polarized beams are not generally sensitive to the source emittance, there are several benefits to a lower source emittance including a simpler more efficient injector system and a lower radiation load during transport especially at bends as at the damping ring. For the ILC, the SHBs could be eliminated if the voltage of the gun is raised sufficiently. Simulations using the General Particle Tracer (GPT) package indicate that a cathode bias voltage of ≥200 kV should allow both SHBs to be operated at 433 or even 650 MHz, while ≥500 kV would be required to eliminate the SHBs altogether. Simulations can be used to determine the minimum emittance possible if the injector is designed for a given increased voltage. A possible alternative to the DC gun is an rf gun. Emittance compensation, routinely used with rf guns, is discussed for higher-voltage DC guns

  20. Low Emittance Guns for the ILC Polarized Electron Beam

    International Nuclear Information System (INIS)

    Clendenin, J.E.; Brachmann, A.; Ioakeimidi, K.; Kirby, R.E.; Maruyama, T.; Miller, R.H.; Wang, J.W.; Zhou, F.; SLAC

    2006-01-01

    Polarized electron beams generated by DC guns are routinely available at several accelerators including JLAB, Mainz and SLAC. These guns operate with a cathode bias on the order of -100 kV. To minimize space charge effects, relatively long bunches are generated at the gun and then compressed longitudinally external to the gun just before and during initial acceleration. For linear colliders, this compression is accomplished using a combination of rf bunchers. For the basic design of the International Linear Collider (ILC), a 120 kV DC photocathode gun is used to produce a series of nanosecond bunches that are each compressed by two sub-harmonic bunchers (SHBs) followed by an L-band buncher and capture section. The longitudinal bunching process results in a significantly higher emittance than produced by the gun alone. While high-energy experiments using polarized beams are not generally sensitive to the source emittance, there are several benefits to a lower source emittance including a simpler more efficient injector system and a lower radiation load during transport especially at bends as at the damping ring. For the ILC, the SHBs could be eliminated if the voltage of the gun is raised sufficiently. Simulations using the General Particle Tracer (GPT) package indicate that a cathode bias voltage of (ge)200 kV should allow both SHBs to be operated at 433 or even 650 MHz, while (ge)500 kV would be required to eliminate the SHBs altogether. Simulations can be used to determine the minimum emittance possible if the injector is designed for a given increased voltage. A possible alternative to the DC gun is an rf gun. Emittance compensation, routinely used with rf guns, is discussed for higher-voltage DC guns

  1. Investigation of Beam Emittance and Beam Transport Line Optics on Polarization

    Energy Technology Data Exchange (ETDEWEB)

    Fiedler, Andrew [Northern Illinois U.; Syphers, Michael [Fermilab

    2017-10-06

    Effects of beam emittance, energy spread, optical parameters and magnet misalignment on beam polarization through particle transport systems are investigated. Particular emphasis will be placed on the beam lines being used at Fermilab for the development of the muon beam for the Muon g-2 experiment, including comparisons with the natural polarization resulting from pion decay, and comments on the development of systematic correlations among phase space variables.

  2. High-Precision Resonant Cavity Beam Position, Emittance and Third-Moment Monitors

    CERN Document Server

    Barov, Nikolai; Miller, Roger H; Nantista, Christopher D; Weidemann, A W

    2005-01-01

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

  3. Emittance Measurements from a Laser Driven Electron Injector

    CERN Document Server

    Reis, D

    2003-01-01

    The Gun Test Facility (GTF) at the Stanford Linear Accelerator Center was constructed to develop an appropriate electron beam suitable for driving a short wavelength free electron laser (FEL) such as the proposed Linac Coherent Light Source (LCLS). For operation at a wavelength of 1.5 (angstrom), the LCLS requires an electron injector that can produce an electron beam with approximately 1 pi mm-mrad normalized rms emittance with at least 1 nC of charge in a 10 ps or shorter bunch. The GTF consists of a photocathode rf gun, emittance-compensation solenoid, 3 m linear accelerator (linac), drive laser, and diagnostics to measure the beam. The rf gun is a symmetrized 1.6 cell, s-band high gradient, room temperature, photocathode structure. Simulations show that this gun when driven by a temporally and spatially shaped drive laser, appropriately focused with the solenoid, and further accelerated in linac can produce a beam that meets the LCLS requirements. This thesis describes the initial characterization of the ...

  4. The optics, emittance, and brightness of the reflected beam sputter source

    International Nuclear Information System (INIS)

    White, N.R.

    1983-01-01

    The emittance of the reflected beam sputter source is shown to be low, and the brightness high. However, the emittance is very variable. The internal optical behaviour of the source has been found to be complex, and to depend strongly on space charge. This adversely affects the stability of the negative ion beam, and causes the variability seen in the emittance. The source, and hence the beam, lacks symmetry, and this lack adversely affects its matching properties and stability. (orig.)

  5. Longitudinal emittance reduction in LEIR of ion beams for LHC

    CERN Document Server

    Angoletta, M E; Findlay, A; Hancock, S; Manglunki, D

    2014-01-01

    For the 2013 LHC ion run the anticipated request for batches from the PS Complex comprising four ion bunches spaced by 100 ns was changed to batches of two bunches spaced by 200 ns. This modified demand was met by suppressing a splitting step in the PS machine, but with the consequence of halving the longitudinal emittance required from LEIR. Thus NOMINAL Pb54+ beams from LEIR had to be delivered inside ~9 eVs to provide sufficient blow-up margin in the PS. Machine Development (MD) sessions were carried out in LEIR to investigate methods to satisfy these stricter requirements. Two main ingredients were found to reduce longitudinal emittance. The first and most important was to adjust carefully the frequency offset at capture in order to align the RF with the position where the beam is deposited by the electron cooling system prior to acceleration. The second ingredient was to reduce the final bucket area in order to reduce any residual filamentation during capture. This note documents the results obtaine...

  6. New beam-based and direct magnetic waveform measurements of the BTx.KFA10(20) vertical recombination kickers and induced emittance blow-up simulations at 1.4 and 2 GeV

    CERN Document Server

    Forte, Vincenzo; Borburgh, Jan; Sermeus, Luc; CERN. Geneva. ATS Department

    2018-01-01

    In the framework of the LHC Injectors Upgrade (LIU) project [1], this document summarises a new reconstruction methodology for the measurement of the magnetic waveforms of the vertical re-combination kickers BT1.KFA10, BT4.KFA10 and BT2.KFA20, from data collected during several Machine Development (MD) sessions. The reconstruction has been performed in order to verify the LIU specification of the recombination kickers, which is required for a clean transfer of the longer bunches coming from the PSB after the upgrade. A beam-based methodology was developed to measure the transient magnetics dynamics of the kicker where the bunch length is comparable to the rise and/or fall times. These measurements represent a valuable way to reconstruct the mag-netic waveform of the kickers where removing them to make direct probe measurements is time consuming. A benchmarking of the beam-based measurements with field probe measurements is presented, together with realistic simulations of the vertical emittance blow-up at 1...

  7. Self-consistent β functions and emittances of round colliding beams

    Directory of Open Access Journals (Sweden)

    A. V. Otboyev

    1999-10-01

    Full Text Available The flip-flop effect with the linearized beam-beam force is formulated through self-consistent β functions and equilibrium emittances which are both affected by collision. We give the results of two models of emittance dependence. The effect of finite bunch length is also discussed.

  8. Transport and acceleration of low-emittance electron beams

    International Nuclear Information System (INIS)

    Henke, H.

    1989-01-01

    Linear accelerators for colliders and for free-electron lasers require beams with both high brightness and low emittance. Their transport and acceleration is limited by single-particle effects originating from injection jitter, from the unavoidable position jitter of components, and from chromaticity. Collective phenomena, essentially due to wake fields acting within the bunch, are most severe in the case of high-frequency structures, i.e. a small aperture. Whilst, in the past, the transverse wake-field effects were believed to be most serious, we know that they can even be beneficial when inducing a corresponding spread in betatron oscillation either by an energy spread along the bunch or by an RF focusing system acting on the bunch scale. This paper evaluates the different effects by simple analytical means after making use of the smooth focusing approximation and the two-particle model. Numerical simulation results are used for verification. 14 refs., 6 figs., 2 tabs

  9. Transverse-to-longitudinal Emittance-exchange with an Energy Chirped Beam

    Energy Technology Data Exchange (ETDEWEB)

    Thangaraj, J.; Ruan, J.; Johnson, A.S.; Thurman-Keup, R.; Lumpkin, A.H.; Santucci, J.; Sun, Y.-E; Maxwell, T.; Edwards, H.; /Fermilab

    2012-05-01

    Emittance exchange has been proposed to increase the performance of free electron lasers by tailoring the phase space of an electron beam. The principle of emittance exchange - where the transverse phase space of the electron beam is exchanged with the longitudinal phase space - has been demonstrated recently at the A0 photoinjector. The experiment used a low charge bunch (250 pC) with no energy chirp. Theory predicts an improvement in the emittance exchange scheme when the incoming beam has an energy chirp imparted on it. The energy chirp helps to overcome the thick lens effect of the deflecting mode cavity and other second order effects that might lead to an incomplete emittance exchange at higher charges. In this work, we report experimental and simulation results from operating the emittance exchange beam line using an energy chirped beam with higher charge (500 pC) at different RF-chirp settings.

  10. Thermal Emittance Measurement of the Cs2Te Photocathode in FZD Superconducting RF

    CERN Document Server

    Xiang, R; Michel, P; Murcek, P; Teichert, J

    2010-01-01

    The thermal emittance of the photocathode is an interesting physical property for the photoinjector, because it decides the minimum emittance the photoinjector can finally achieve. In this paper we will report the latest results of the thermal emittance of the Cs2Te photocathode in FZD Superconducting RF gun. The measurement is performed with solenoid scan method with very low bunch charge and relative large laser spot on cathode, in order to reduce the space charge effect as much as possible, and meanwhile to eliminate the wake fields and the effect from beam halos.

  11. Generation of low-emittance electron beams in electrostatic accelerators for FEL applications

    International Nuclear Information System (INIS)

    Chen Teng; Central Florida Univ., Orlando, FL; Elias, L.R. R.; Central Florida Univ., Orlando, FL

    1995-01-01

    This paper reports results of transverse emittance studies and beam propagation in electrostatic accelerators for free electron laser applications. In particular, we discuss emittance growth analysis of a low current electron beam system consisting of a miniature thermoionic electron gun and a National Electrostatics Accelerator (NEC) tube. The emittance growth phenomenon is discussed in terms of thermal effects in the electron gun cathode and aberrations produced by field gradient changes occurring inside the electron gun and throughout the accelerator tube. A method of reducing aberrations using a magnetic solenoidal field is described. Analysis of electron beam emittance was done with the EGUN code. Beam propagation along the accelerator tube was studied using a cylindrically symmetric beam envelope equation that included beam self-fields and the external accelerator fields which were derived from POISSON simulations. ((orig.))

  12. Design and Development of Emittance Measurement Device by Using the Pepper-pot Technique

    Science.gov (United States)

    Pakluea, S.; Rimjaem, S.

    2017-09-01

    Transverse emittance of a charged particle beam is one of the most important properties that reveals the quality of the beam. It is related to charge density, transvers size and angular displacement of the beam in transverse phase space. There are several techniques to measure the transverse emittance value. One of practical methods is the pepper-pot technique, which can measure both horizontal and vertical emittance value in a single measurement. This research concentrates on development of a pepper-pot device to measure the transverse emittance of electron beam produced from an accelerator injector system, which consists of a thermionic cathode RF electron gun and an alpha magnet, at the Plasma and Beam Physics Research Facility, Chiang Mai University. Simulation of beam dynamics was conducted with programs PARMELA, ELEGANT and self-developed codes using C and MATLAB. The geometry, dimensions and location of the pepper-pot as well as its corresponding screen station position were included in the simulation. The result from this study will be used to design and develop a practical pepper-pot experimental station.

  13. Investigation of slice emittance using an energy-chirped electron beam in a dispersive section for photo injector characterization at PITZ

    Energy Technology Data Exchange (ETDEWEB)

    Ivanisenko, Yevgeniy

    2012-06-15

    This work describes a transverse slice emittance diagnostics with an RMS temporal resolution down to 2 ps that was implemented at the Photo Injector Test facility in Zeuthen (PITZ). The measurements were performed for several bunch charges generated by a laser pulse that has a flat-top temporal profile of 21-22 ps FWHM duration. This diagnostics allows to study the beam projected emittance compensation with a solenoid magnetic field experimentally and therefore contributes to the beam emittance optimization for the needs of short wavelength linac-based FELs in particular. The diagnostics is based upon the usage of electron bunches which have a correlation between the longitudinal position and the momentum of the bunch particles. This property allows to convert the bunch longitudinal distribution into a transverse one in a dipole magnet. A slit with a narrow opening at the dipole exit selects a fraction of the particle ensemble, a slice, which emittance is analyzed at a screen downstream. Slit scan and quadrupole scan techniques can be used to measure the emittance of the slices. In the experiments it was found that the slice emittance values are 5-10% lower than the projected emittance values, indicating a good effectivity of the solenoid compensation. The emittance obtained using quadrupole scan technique has shown different results when compared to slit scan technique due to a beam halo. The observed beam halo in phase space contributes up to 40% of the emittance value while having only 10% of the bunch charge.

  14. A correction for emittance-measurement errors caused by finite slit and collector widths

    International Nuclear Information System (INIS)

    Connolly, R.C.

    1992-01-01

    One method of measuring the transverse phase-space distribution of a particle beam is to intercept the beam with a slit and measure the angular distribution of the beam passing through the slit using a parallel-strip collector. Together the finite widths of the slit and each collector strip form an acceptance window in phase space whose size and orientation are determined by the slit width, the strip width, and the slit-collector distance. If a beam is measured using a detector with a finite-size phase-space window, the measured distribution is different from the true distribution. The calculated emittance is larger than the true emittance, and the error depends both on the dimensions of the detector and on the Courant-Snyder parameters of the beam. Specifically, the error gets larger as the beam drifts farther from a waist. This can be important for measurements made on high-brightness beams, since power density considerations require that the beam be intercepted far from a waist. In this paper we calculate the measurement error and we show how the calculated emittance and Courant-Snyder parameters can be corrected for the effects of finite sizes of slit and collector. (Author) 5 figs., 3 refs

  15. Electron beam measurements on the Daresbury SRS

    International Nuclear Information System (INIS)

    Laundy, D.; Cummings, S.

    1992-01-01

    Two experiments which use hard x-ray synchrotron radiation have been carried out to allow us to monitor the electron beam on the Daresbury SRS. The beam spatial and angular vertical position and size was determined over a period of time when the SRS was operating normally. From these measurements, the position and angular stability of the electron beam during the measurement period was assessed and correlation of the beam emittance to the electron current was determined

  16. Possibilities for reduction of transverse projected emittances by partial removal of transverse to longitudinal beam correlations

    International Nuclear Information System (INIS)

    Balandin, V.; Decking, W.; Golubeva, N.

    2014-09-01

    We show that if in the particle beam there are linear correlations between energy of particles and their transverse positions and momenta (linear beam dispersions), then the transverse projected emittances always can be reduced by letting the beam to pass through magnetostatic system with specially chosen nonzero lattice dispersions. The maximum possible reduction of the transverse projected emittances occurs when all beam dispersions are zeroed, and the values of the lattice dispersions required for that are completely defined by the values of the beam dispersions and the beam rms energy spread and are independent from any other second-order central beam moments. Besides that, we prove that, alternatively, one can also use the lattice dispersions to remove linear correlations between longitudinal positions of particles and their transverse coordinates (linear beam tilts), but in this situation solution for the lattice dispersions is nonunique and the reduction of the transverse projected emittances is not guaranteed.

  17. Numerical studies of emittance exchange in 2-D charged-particle beams

    International Nuclear Information System (INIS)

    Guy, F.W.

    1986-01-01

    We describe results obtained from a two-dimensional particle-following computer code that simulates a continuous, nonrelativistic, elliptical charged-particle beam with linear continuous focusing. Emittances and focusing strengths can be different in the two transverse directions. The results can be applied, for example, for a quadrupole transport system in a smooth approximation to a real beam with unequal emittances in the two planes. The code was used to study emittance changes caused by kinetic-energy exchange between transverse directions and by shifts in charge distributions. Simulation results for space-charge-dominated beams agree well with analytic formulas. From simulation results, an empirical formula was developed for a ''partition parameter'' (the ratio of kinetic energies in the two directions) as a function of initial conditions and beamline length. Quantitative emittance changes for each transverse direction can be predicted by using this parameter. Simulation results also agree with Hofmann's generalized differential equation relating emittance and field energy

  18. Investigation of effect of solenoid magnet on emittances of ion beam from laser ablation plasma

    Science.gov (United States)

    Ikeda, Shunsuke; Romanelli, Mark; Cinquegrani, David; Sekine, Megumi; Kumaki, Masafumi; Fuwa, Yasuhiro; Kanesue, Takeshi; Okamura, Masahiro; Horioka, Kazuhiko

    2014-02-01

    A magnetic field can increase an ion current of a laser ablation plasma and is expected to control the change of the plasma ion current. However, the magnetic field can also make some fluctuations of the plasma and the effect on the beam emittance and the emission surface is not clear. To investigate the effect of a magnetic field, we extracted the ion beams under three conditions where without magnetic field, with magnetic field, and without magnetic field with higher laser energy to measure the beam distribution in phase space. Then we compared the relations between the plasma ion current density into the extraction gap and the Twiss parameters with each condition. We observed the effect of the magnetic field on the emission surface.

  19. Investigation of effect of solenoid magnet on emittances of ion beam from laser ablation plasma

    International Nuclear Information System (INIS)

    Ikeda, Shunsuke; Sekine, Megumi; Romanelli, Mark; Cinquegrani, David; Kumaki, Masafumi; Fuwa, Yasuhiro; Kanesue, Takeshi; Okamura, Masahiro; Horioka, Kazuhiko

    2014-01-01

    A magnetic field can increase an ion current of a laser ablation plasma and is expected to control the change of the plasma ion current. However, the magnetic field can also make some fluctuations of the plasma and the effect on the beam emittance and the emission surface is not clear. To investigate the effect of a magnetic field, we extracted the ion beams under three conditions where without magnetic field, with magnetic field, and without magnetic field with higher laser energy to measure the beam distribution in phase space. Then we compared the relations between the plasma ion current density into the extraction gap and the Twiss parameters with each condition. We observed the effect of the magnetic field on the emission surface

  20. Experimental studies on coherent synchrotron radiation at an emittance exchange beam line

    Directory of Open Access Journals (Sweden)

    J. C. T. Thangaraj

    2012-11-01

    Full Text Available One of the goals of the Fermilab A0 photoinjector is to investigate experimentally the transverse to longitudinal emittance exchange (EEX principle. Coherent synchrotron radiation in the emittance exchange line could limit the performance of the emittance exchanger at short bunch lengths. In this paper, we present experimental and simulation studies of the coherent synchrotron radiation (CSR in the emittance exchange line at the A0 photoinjector. We report on time-resolved CSR studies using a skew-quadrupole technique. We also demonstrate the advantages of running the EEX with an energy-chirped beam.

  1. Initial observations of high-charge, low-emittance electron beams at HIBAF (High Brightness Accelerator FEL)

    Energy Technology Data Exchange (ETDEWEB)

    Lumpkin, A.H.; Feldman, R.B.; Carsten, B.E.; Feldman, D.W.; Sheffield, R.L.; Stein, W.E.; Johnson, W.J.; Thode, L.E.; Bender, S.C.; Busch, G.E.

    1990-01-01

    We report our initial measurements of bright (high-charge, low-emittance) electron beams generated at the Los Alamos High Brightness Accelerator FEL (HIBAF) Facility. Normalized emittance values of less than 50 {pi} mm-mrad for charges ranging from 0.7 to 8.7 nC were obtained for single micropulses at a y-waist and at an energy of 14.7 MeV. These measurements were part of the commissioning campaign on the HIBAF photoelectric injector. Macropulse measurements have also been performed and are compared with PARMELA simulations. 5 refs., 8 figs., 3 tabs.

  2. On the feasibility of sub-100 nm rad emittance measurement in plasma accelerators using permanent magnetic quadrupoles

    Science.gov (United States)

    Li, F.; Wu, Y. P.; Nie, Z.; Guo, B.; Zhang, X. H.; Huang, S.; Zhang, J.; Cheng, Z.; Ma, Y.; Fang, Y.; Zhang, C. J.; Wan, Y.; Xu, X. L.; Hua, J. F.; Pai, C. H.; Lu, W.; Gu, Y. Q.

    2018-01-01

    Low emittance (sub-100 nm rad) measurement of electron beams in plasma accelerators has been a challenging issue for a while. Among various measurement schemes, measurements based on single-shot quad-scan using permanent magnetic quadrupoles (PMQs) has been recently reported with emittance as low as ∼200 nm Weingartner (2012 Phys. Rev. Spec. Top. Accel. Beams 15 111302). However, the accuracy and reliability of this method have not been systematically analyzed. Such analysis is critical for evaluating the potential of sub-100 nm rad emittance measurement using any scheme. In this paper, we analyze the effects of various nonideal physical factors on the accuracy and reliability using the PMQ method. These factors include aberration induced by a high order field, PMQ misalignment and angular fluctuation of incoming beams. Our conclusions are as follows: (i) the aberrations caused by high order fields of PMQs are relatively weak for low emittance measurement as long as the PMQs are properly constructed. A series of PMQs were manufactured and measured at Tsinghua University, and using numerical simulations their high order field effects were found to be negligible . (ii) The largest measurement error of emittance is caused by the angular misalignment between PMQs. For low emittance measurement of ∼100 MeV beams, an angular alignment accuracy of 0.1° is necessary. This requirement can be eased for beams with higher energies. (iii) The transverse position misalignment of PMQs and angular fluctuation of incoming beams only cause a translational and rotational shift of measured signals, respectively, therefore, there is no effect on the measured value of emittance. (iv) The spatial resolution and efficiency of the detection system need to be properly designed to guarantee the accuracy of sub-100 nm rad emittance measurement.

  3. MICE: the Muon Ionization Cooling Experiment. Step I: First Measurement of Emittance with Particle Physics Detectors

    CERN Document Server

    Bravar, U; Karadzhov, Y; Kolev, D; Russinov, I; Tsenov, R; Wang, L; Xu, F Y; Zheng, S X; Bertoni, R; Bonesini, M; Mazza, R; Palladino, V; Cecchet, G; de Bari, A; Capponi, M; Iaciofano, A; Orestano, D; Pastore, F; Tortora, L; Ishimoto, S; Suzuki, S; Yoshimura, K; Mori, Y; Kuno, Y; Sakamoto, H; Sato, A; Yano, T; Yoshida, M; Filthaut, F; Vretenar, M; Ramberger, S; Blondel, A; Cadoux, F; Masciocchi, F; Graulich, J S; Verguilov, V; Wisting, H; Petitjean, C; Seviour, R; Ellis, M; Kyberd, P; Littlefield, M; Nebrensky, J J; Forrest, D; Soler, F J P; Walaron, K; Cooke, P; Gamet, R; Alecou, A; Apollonio, M; Barber, G; Dobbs, A; Dornan, P; Fish, A; Hare, R; Jamdagni, A; Kasey, V; Khaleeq, M; Long, K; Pasternak, J; Sakamoto, H; Sashalmi, T; Blackmore, V; Cobb, J; Lau, W; Rayner, M; Tunnell, C D; Witte, H; Yang, S; Alexander, J; Charnley, G; Griffiths, S; Martlew, B; Moss, A; Mullacrane, I; Oats, A; York, S; Apsimon, R; Alexander, R J; Barclay, P; Baynham, D E; Bradshaw, T W; Courthold, M; Hayler, R Edgecock T; Hills, M; Jones, T; McNubbin, N; Murray, W J; Nelson, C; Nicholls, A; Norton, P R; Prior, C; Rochford, J H; Rogers, C; Spensley, W; Tilley, K; Booth, C N; Hodgson, P; Nicholson, R; Overton, E; Robinson, M; Smith, P; Adey, D; Back, J; Boyd, S; Harrison, P; Norem, J; Bross, A D; Geer, S; Moretti, A; Neuffer, D; Popovic, M; Qian, Z; Raja, R; Stefanski, R; Cummings, M A C; Roberts, T J; DeMello, A; Green, M A; Li, D; Sessler, A M; Virostek, S; Zisman, M S; Freemire, B; Hanlet, P; Huang, D; Kafka, G; Kaplan, D M; Snopok, P; Torun, Y; Onel, Y; Cline, D; Lee, K; Fukui, Y; Yang, X; Rimmer, R A; Cremaldi, L M; Hart, T L; Summers, D J; Coney, L; Fletcher, R; Hanson, G G; Heidt, C; Gallardo, J; Kahn, S; Kirk, H; Palmer, R B; C11-08-09

    2011-01-01

    The Muon Ionization Cooling Experiment (MICE) is a strategic R&D project intended to demonstrate the only practical solution to providing high brilliance beams necessary for a neutrino factory or muon collider. MICE is under development at the Rutherford Appleton Laboratory (RAL) in the United Kingdom. It comprises a dedicated beamline to generate a range of input muon emittances and momenta, with time-of-flight and Cherenkov detectors to ensure a pure muon beam. The emittance of the incoming beam will be measured in the upstream magnetic spectrometer with a scintillating fiber tracker. A cooling cell will then follow, alternating energy loss in Liquid Hydrogen (LH2) absorbers to RF cavity acceleration. A second spectrometer, identical to the first, and a second muon identification system will measure the outgoing emittance. In the 2010 run at RAL the muon beamline and most detectors were fully commissioned and a first measurement of the emittance of the muon beam with particle physics (time-of-flight) de...

  4. Correction of nonlinear distortion in high-transverse-emittance ratio-beam production with linear accelerator

    Directory of Open Access Journals (Sweden)

    Shaoheng Wang

    2008-05-01

    Full Text Available Derbenev proposed producing a high quality flat beam of high-transverse-emittance ratio (HTER with a linear accelerator. Kim also discussed the round-to-flat transformation of angular-momentum-dominated beam. Fermilab/NICADD Photoinjector Laboratory has performed many experiments on HTER beam production. Experiments and simulations, collectively, showed an S-shaped transverse distribution in the flat beam. In this paper, the source of this emittance deterioration in the transformation is identified as the nonlinear rf cavity focusing force; and a solution is proposed.

  5. Beam parameters of a possible emittance-dynamics test area for NLC studies at the SLC

    International Nuclear Information System (INIS)

    Seeman, J.T.; Fieguth, T.; Kheifets, S.; Raubenheimer, T.; Yeremian, A.D.

    1992-08-01

    A group at SLAC has studied the possibility of using the Stanford Linear Collider (SLC) to generate short-bunch small-emittance beams similar to those required for the Next Linear Collider (NLC). The conclusion is that such beams are feasible and that an experimental area for testing many concepts related to NLC beams can be provided with a reasonable addition of hardware to the existing SLC Linac. Some of the concepts that can be tested are: (1) effect tolerances of double bunch length compression, (2) wakefields of ultra-short bunches in accelerating structures, (3) the acceleration of short intense multiple bunches, (4) the generation and preservation of bunches with 100 to 1 emittances ratios, (5) beam deflections by collimators, (6) energy and energy spread control of multiple short bunches, and (7) vibration effects and trajectory stability for low emittance beams

  6. Test results of the signal processing and amplifier unit for the emittance measurement system

    International Nuclear Information System (INIS)

    Stawiszynski, L.; Schneider, S.

    1984-01-01

    The signal processing and amplifier unit for the emittance measurement system is the unit with which the beam current on the harp-wires and the slit is measured and converted to a digital output. Temperature effects are very critical at low currents and the purpose of the test measurements described in this report was mainly to establish the accuracy and repeatability of the measurements under the influence of temperature variations

  7. Cross section measurements for production of positron emitters for PET imaging in carbon therapy

    Science.gov (United States)

    Salvador, S.; Colin, J.; Cussol, D.; Divay, C.; Fontbonne, J.-M.; Labalme, M.

    2017-04-01

    In light ion beam therapy, positron (β+) emitters are produced by the tissue nuclei through nuclear interactions with the beam ions. They can be used for the verification of the delivered dose using positron emission tomography by comparing the spatial distribution of the β+ emitters activity to a computer simulation taking into account the patient morphology and the treatment plan. However, the accuracy of the simulation greatly depends on the method used to generate the nuclear interactions producing these emitters. In the case of Monte Carlo (MC) simulations, the nuclear interaction models still lack the required accuracy due to insufficient experimental cross section data. This is particularly true for carbon therapy where literature data on fragmentation cross sections of a carbon beam with targets of medical interest are very scarce. Therefore, we performed at GANIL in July 2016 measurements on β+ emitter production cross sections with a carbon beam at 25, 50, and 95 MeV/nucleon on thin targets (C, N, O, and PMMA). We extracted the production cross section of C,1110, 13N, and O,1514 that are essential to constrain or develop MC nuclear fragmentation models.

  8. Measurement of transverse emittance at the source of spin-polarized electrons at the S-DALINAC

    Energy Technology Data Exchange (ETDEWEB)

    Eckardt, Christian; Barday, Roman; Bonnes, Uwe; Eichhorn, Ralf; Enders, Joachim; Hessler, Christoph; Patalakha, Oleksandr; Platz, Markus; Poltoratska, Yuliya; Rick, Wolfgang [Institut fuer Kernphysik, TU Darmstadt (Germany); Ackermann, Wolfgang; Mueller, Wolfgang F.O.; Steiner, Bastian; Weiland, Thomas [Institut fuer Theorie Elektromagnetischer Felder, TU Darmstadt (Germany)

    2008-07-01

    A new injector concept for 100 keV spin-polarized electrons (SPIN) at the S-DALINAC has been developed. The transverse emittance was measured for beam characterization. The emittance is a quantity concerning the quality of the beam, describing the phase space area. Determination of the emittance requires measurement of the beam profile and knowledge of the focal length of a beam focussing device. A wire scanner unit consisting of two 50 {mu}m diameter tungsten wires is used for the beam-profile measurement. Data analysis is performed by fitting a gaussian model distribution to estimate the 1{sigma} beam radius. Each determined beam width is correlated to the corresponding focal length of a magnetic lens, and a parabola fit is applied to calculate the parameters of the {sigma}-matrix. The square root of the determinant of the {sigma}-matrix defines the emittance. The results of the calculation are presented and the emittance is compared to theoretical estimates.

  9. Beam based measurement of beam position monitor electrode gains

    OpenAIRE

    D. L. Rubin; M. Billing; R. Meller; M. Palmer; M. Rendina; N. Rider; D. Sagan; J. Shanks; C. Strohman

    2010-01-01

    Low emittance tuning at the Cornell Electron Storage Ring (CESR) test accelerator depends on precision measurement of vertical dispersion and transverse coupling. The CESR beam position monitors (BPMs) consist of four button electrodes, instrumented with electronics that allow acquisition of turn-by-turn data. The response to the beam will vary among the four electrodes due to differences in electronic gain and/or misalignment. This variation in the response of the BPM electrodes will couple ...

  10. A concept for emittance reduction of DC radioactive heavy-ion beams

    International Nuclear Information System (INIS)

    Nolen, J.A.; Dooling, J.C.

    1995-01-01

    Numerical simulations indicate that it should be possible to use an electron beam to strip 1+ DC radioactive ion beams to 2+ or higher charge states with on the order of 50% efficiency. The device, which the authors call an Electron-Beam Charge-State Amplifier, is similar to an Electron Beam Ion Source, except that it is not pulsed, the beams are continuous. The 2+ beams are obtained in a single pass through a magnetic solenoid while higher charge states may be reached via multiple passes. An unexpected result of the ion optics simulations is that the normalized transverse emittance of the ion beam is reduced in proportion to the charge-state gain. Ion beams with realistic emittances and zero angular momentum relative to the optic axis before entering the solenoid will travel though the solenoid on helical orbits which intercept the axis once per cycle. With an ion beam about 2 mm in diameter and an electron beam about 0.2 mm in diameter, the ion stripping only occurs very near the optic axis, resulting in the emittance reduction

  11. Pyrometric method for measuring emittances at high temperatures

    Science.gov (United States)

    Ballestrín, J.; Rodríguez, J.; Carra, M. E.; Cañadas, I.; Roldan, M. I.; Barbero, J.; Marzo, A.

    2016-05-01

    In this work an alternative method for emittance determination based on pyrometric measurements is presented. The measurement procedure has been applied to AISI 310S steel samples in the Plataforma Solar de Almería vertical axis solar furnace SF5. The experimental results show that emittance increases with increasing temperature and decreases with increasing wavelength. This behaviour is in agreement with experimental results obtained by other authors. Analysis of tests has revealed a good repeatability (1%) and accuracy (< 2%) of this measurement procedure.

  12. The generation and acceleration of low emittance flat beams for future linear colliders

    Energy Technology Data Exchange (ETDEWEB)

    Raubenheimer, Tor O. [Stanford Univ., CA (United States)

    1991-11-01

    Many future linear collider designs call for electron and positron beams with normalized rms horizontal and vertical emittances of γϵx = 3x10-6 m-rad and γϵy = 3x10-8 m-rad; these are a factor of 10 to 100 below those observed in the Stanford Linear Collider. In this dissertation, we examine the feasibility of achieving beams with these very small vertical emittances. We examine the limitations encountered during both the generation and the subsequent acceleration of such low emittance beams. We consider collective limitations, such as wakefields, space charge effects, scattering processes, and ion trapping; and also how intensity limitations, such as anomalous dispersion, betatron coupling, and pulse-to-pulse beam jitter. In general, the minimum emittance in both the generation and the acceleration stages is limited by the transverse misalignments of the accelerator components. We describe a few techniques of correcting the effect of these errors, thereby easing the alignment tolerances by over an order of magnitude. Finally, we also calculate ``fundamental`` limitations on the minimum vertical emittance; these do not constrain the current designs but may prove important in the future.

  13. The generation and acceleration of low emittance flat beams for future linear colliders

    Energy Technology Data Exchange (ETDEWEB)

    Raubenheimer, T.O.

    1991-11-01

    Many future linear collider designs call for electron and positron beams with normalized rms horizontal and vertical emittances of {gamma}{epsilon}{sub x} = 3{times}10{sup {minus}6} m-rad and {gamma}{epsilon}{sub y} = 3{times}10{sup {minus}8} m-rad; these are a factor of 10 to 100 below those observed in the Stanford Linear Collider. In this dissertation, we examine the feasibility of achieving beams with these very small vertical emittances. We examine the limitations encountered during both the generation and the subsequent acceleration of such low emittance beams. We consider collective limitations, such as wakefields, space charge effects, scattering processes, and ion trapping; and also how intensity limitations, such as anomalous dispersion, betatron coupling, and pulse-to-pulse beam jitter. In general, the minimum emittance in both the generation and the acceleration stages is limited by the transverse misalignments of the accelerator components. We describe a few techniques of correcting the effect of these errors, thereby easing the alignment tolerances by over an order of magnitude. Finally, we also calculate fundamental'' limitations on the minimum vertical emittance; these do not constrain the current designs but may prove important in the future.

  14. The generation and acceleration of low emittance flat beams for future linear colliders

    International Nuclear Information System (INIS)

    Raubenheimer, T.O.

    1991-11-01

    Many future linear collider designs call for electron and positron beams with normalized rms horizontal and vertical emittances of γε x = 3x10 -6 m-rad and γε y = 3x10 -8 m-rad; these are a factor of 10 to 100 below those observed in the Stanford Linear Collider. In this dissertation, we examine the feasibility of achieving beams with these very small vertical emittances. We examine the limitations encountered during both the generation and the subsequent acceleration of such low emittance beams. We consider collective limitations, such as wakefields, space charge effects, scattering processes, and ion trapping; and also how intensity limitations, such as anomalous dispersion, betatron coupling, and pulse-to-pulse beam jitter. In general, the minimum emittance in both the generation and the acceleration stages is limited by the transverse misalignments of the accelerator components. We describe a few techniques of correcting the effect of these errors, thereby easing the alignment tolerances by over an order of magnitude. Finally, we also calculate ''fundamental'' limitations on the minimum vertical emittance; these do not constrain the current designs but may prove important in the future

  15. Low emittance growth in a low energy beam transport line with un-neutralized section

    Science.gov (United States)

    Prost, L.; Carneiro, J.-P.; Shemyakin, A.

    2018-02-01

    In a low energy beam transport line (LEBT), the emittance growth due to the beam's space charge is typically suppressed by way of neutralization from either electrons or ions, which originate from ionization of the background gas. In cases where the beam is chopped, the neutralization pattern usually changes throughout the beginning of the pulse, causing the Twiss parameters to differ significantly from their steady state values, which, in turn, may result in beam losses downstream. For a modest beam perveance, there is an alternative solution, in which the beam is kept un-neutralized in the portion of the LEBT that contains the chopper. The emittance can be nearly preserved if the transition to the un-neutralized section occurs where the beam exhibits low transverse tails. This report introduces the rationale for the proposed scheme and formulates the physical arguments for it as well as its limitations. An experimental realization of the scheme was carried out at Fermilab's PIP2IT where low beam emittance dilution was demonstrated for a 5 mA, 30 keV H- beam.

  16. Passive emitter location with Doppler frequency and interferometric measurements

    NARCIS (Netherlands)

    Groot, J.S.; Dam, F.A.M.; Theil, A.

    2008-01-01

    Ground based emitters can be located with a receiver installed on an airborne platform. This paper discusses techniques based on Doppler frequency and differential phase measurements (interferometry). Measurements of the first technique are provided, while we discuss and compare the theoretical

  17. Emittance Measurements at the Langley Chemical Physics Laboratory

    Science.gov (United States)

    Lewis, B. W.

    1960-01-01

    Total hemispherical emittance measurements are made routinely for materials which may be heated by electrical resistance methods over the temperature range of 600 degrees to 2,000 F by using a black-body reference method. This employs a conical black body and a thermopile detector with a calcium fluoride lens. Emittance is obtained by measuring the radiant flux from the specimen strip and comparing it with the flux from an equal area of the black-body cone at the same temperature. The temperature measurements are made by use of thermocouples. It is planned to extend the temperature range of this type of measurement to temperatures above 2,000 F. Another technique has been investigated for measuring emittance of materials not amenable to electrical heating or thermocouple attachment. This method uses a black-body-cavity furnace similar to that used in reference 5 to measure emittance of transparent materials such as glass. The method employs a heated black-body cavity in which the semicircular specimen is allowed to come to the equilibrium temperature of the cavity and then is rotated in front of a water-cooled viewing port where a sensitive thermistor detector alternately views the specimen surface and the black-body cavity. The ratio of the two readings gives the specimen emittance directly, for the temperature of the black body. The detector output is recorded on a fast Brown self-balancing potentiometer. The furnace is provided with a water-cooled blackened shutter which may be inserted behind the specimen to eliminate any transmitted black-body radiation if the specimen is transparent. This apparatus is capable of measuring total normal emittance over the temperature range of 1,000 degrees to 2,000 F. Preliminary data for boron nitride specimens of two thicknesses are shown where total normal emittance is plotted against temperature for two experimental conditions: (1) black-body radiation incident on the back of the specimen and (2) no black-body radiation

  18. Internal dynamics and emittance growth in space-charge-dominated beams

    International Nuclear Information System (INIS)

    Anderson, O.A.

    1987-01-01

    Previous analytical studies have related transverse rms emittance growth in nonuniform beams to changes in the beam density profile, but the time evolution of the process has not been analyzed. Our new approach analyzes the internal motion of the beam and from this obtains the explicit time dependence of the rms emittance. It is shown to reach its peak value explosively in about one quarter of a plasma period. The subsequent behavior depends on the uniformity of the initial density profile. We derive a uniformity criterion that determines whether or not the emittance oscillates periodically and present examples of density profiles for which the emittance returns to its initial value and then continues to oscillate. We discuss a class of continuous initial profiles that lead to discontinuous shocklike behavior (with partial irreversibility of the oscillations) and a class of segmented profiles for which the emittance jumps to its maximum value in one fourth of a plasma period and remains at that value with essentially no further change. (author)

  19. Low-emittance tuning of storage rings using normal mode beam position monitor calibration

    Directory of Open Access Journals (Sweden)

    A. Wolski

    2011-07-01

    Full Text Available We describe a new technique for low-emittance tuning of electron and positron storage rings. This technique is based on calibration of the beam position monitors (BPMs using excitation of the normal modes of the beam motion, and has benefits over conventional methods. It is relatively fast and straightforward to apply, it can be as easily applied to a large ring as to a small ring, and the tuning for low emittance becomes completely insensitive to BPM gain and alignment errors that can be difficult to determine accurately. We discuss the theory behind the technique, present some simulation results illustrating that it is highly effective and robust for low-emittance tuning, and describe the results of some initial experimental tests on the CesrTA storage ring.

  20. Selective solar absorber emittance measurement at elevated temperature

    Science.gov (United States)

    Giraud, Philémon; Braillon, Julien; Raccurt, Olivier

    2017-06-01

    Durability of solar components for CSP (Concentrated Solar Power Plant) technologies is a key point to lower cost and ensure their large deployment. These technologies concentrated the solar radiation by means of mirrors on a receiver tube where it is collected as thermal energy. The absorbers are submitted to strong environmental constraints and the degradation of their optical properties (emittance and solar absorbance) have a direct impact on performance. The characterization of a material in such condition is complicated and requires advanced apparatuses, and different measurement methods exist for the determination of the two quantities of relevance regarding an absorber, which are its emittance and its solar absorbance. The objective is to develop new optical equipment for measure the emittance of this solar absorber at elevated temperature. In this paper, we present an optical bench developed for emittance measurement on absorbers is conditions of use. Results will be shown, with a discussion of some factors of influence over this measurement and how to control them.

  1. Emittance growth and halo formation in charge-dominated beams

    Energy Technology Data Exchange (ETDEWEB)

    Bondarev, B.I.; Durkin, A.P.; Murin, B.P. [Moscow Radiotechnical Institute (Russian Federation)] [and others

    1995-10-01

    The optimization of high-current high-energy linacs against the low beam loss requirement is not straightforward or well-codified. Outlying particle losses at the 10{sup {minus}5} up to 10{sup {minus}8} level might have only a small effect on the rms properties of the beam, and thus the total beam size must be constantly kept under observation. RMS-physics has gained wide-spread acceptance as a necessary design tool, but its sufficiency is an issue for ATW/ABC accelerators.

  2. Emittance measurements for optimum operation of the J-PARC RF-driven H{sup −} ion source

    Energy Technology Data Exchange (ETDEWEB)

    Ueno, A., E-mail: akira.ueno@j-parc.jp; Ohkoshi, K.; Ikegami, K.; Takagi, A.; Yamazaki, S.; Oguri, H. [J-PARC Center, Tokai-mura, Naka-gun, Ibaraki-ken 319-1195 (Japan)

    2015-04-08

    In order to satisfy the Japan Proton Accelerator Research Complex (J-PARC) second stage requirements of an H{sup −} ion beam of 60mA within normalized emittances of 1.5πmm•mrad both horizontally and vertically, a flat top beam duty factor of 1.25% (500μs×25Hz) and a life-time of longer than 1month, the J-PARC cesiated RF-driven H{sup −} ion source was developed by using an internal-antenna developed at the Spallation Neutron Source (SNS). The transverse emittances of the source were measured with various conditions to find out the optimum operation conditions minimizing the horizontal and vertical rms normalized emittances. The transverse emittances were most effectively reduced by operating the source with the plasma electrode temperature lower than 70°C. The optimum value of the cesium (Cs) density around the beam hole of the plasma electrode seems to be proportional to the plasma electrode temperature. The fine control of the Cs density is indispensable, since the emittances seem to increase proportionally to the excessiveness of the Cs density. Furthermore, the source should be operated with the Cs density beyond a threshold value, since the plasma meniscus shape and the ellipse parameters of the transverse emittances seem to be changed step-function-likely on the threshold Cs value.

  3. Emittance matching of a slow extracted beam for a rotating gantry

    Science.gov (United States)

    Fujimoto, T.; Iwata, Y.; Matsuba, S.; Fujita, T.; Sato, S.; Shirai, T.; Noda, K.

    2017-09-01

    The introduction of a heavy-ion rotating gantry is in progress at the Heavy Ion Medical Accelerator in Chiba (HIMAC) for realizing high-precision cancer therapy using heavy ions. A scanning irradiation method will be applied to this gantry course with 48-430 MeV/u beam energy. In the rotating gantry, the horizontal and vertical beam parameters are coupled by its rotation. To maintain a circular spot shape at the isocenter irrespective of the gantry angle, achieving symmetric phase space distribution of the horizontal and vertical beam at the entrance of the rotating gantry is necessary. Therefore, compensating the horizontal and vertical emittance is necessary. We consider using a thin scatterer method to compensate the emittance. After considering the optical design for emittance matching, the scatterer device is located in the high-energy beam transport line. In the beam commissioning, we confirm that the symmetrical spot shape is obtained at the isocenter without depending on the gantry angle.

  4. Conceptual Design of an Insertion Device for Non-Destructive Beam Diagnostics of a Low-Emittance Synchrotron Light Source

    CERN Document Server

    Masaki, Mitsuhiro

    2005-01-01

    An insertion device is proposed to measure small vertical angular divergence and energy spread (dE/E) of electron beam in a low-emittance synchrotron light source. In accelerators such as the SPring-8 storage ring operated on the small emittance-coupling ratio, vertical divergence of spectral photon flux produced by electron beam in a conventional undulator of several meters long will be dominated by natural divergence of the undulator radiation. Therefore, the divergence of spectral flux is not useful for vertical emittance diagnostics. The proposed insertion device consists of N short undulator sections as x-ray radiators cascaded through vertical deflective sections to make a half-period cosine-like electron trajectory. Two radiation parts of the upper and lower sides are formed due to up-and-down electron orbit by the deflective sections. X-rays emitted from the two radiation parts interfere at observation point far from the insertion device. It was numerically studied that the vertical angular divergence...

  5. Test beam results of a low-pressure micro-strip gas chamber with a secondary-electron emitter

    International Nuclear Information System (INIS)

    Kwan, S.; Anderson, D.F.; Zimmerman, J.; Sbarra, C.; Salomon, M.

    1994-10-01

    We present recent results, from a beam test, on the angular dependence of the efficiency and the distribution of the signals on the anode strips of a low-pressure microstrip gas chamber with a thick CsI layer as a secondary-electron emitter. New results of CVD diamond films as secondary-electron emitters are discussed

  6. Parallel simulations of partially coherent wavefront propagation from a finite emittance electron beam

    Science.gov (United States)

    Laundy, D.; Sutter, J. P.; Wagner, U. H.; Rau, C.; Thomas, C. A.; Sawhney, K. J. S.; Chubar, O.

    2013-03-01

    Hard X-ray undulator radiation at 3rd generation storage rings falls between the geometrical and the fully coherent limit. This is a result of the small but finite emittance of the electron beam source and means that the radiation cannot be completely modelled by incoherent ray tracing or by fully coherent wave propagation. We have developed using the wavefront propagation code Synchrotron Radiation Workshop (SRW) running in a Python environment, a parallel computer program using the Monte Carlo method for modelling the partially coherent emission from electron beam sources taking into account the finite emittance of the source. Using a parallel computing cluster with in excess of 500 cores and each core calculating the wavefront from in excess of a 1000 electrons, a source containing millions of electrons could be simulated. We have applied this method to the Diamond X-ray Imaging and Coherence beamline (113).

  7. Beam emittance and the effects of the rf, space charge and wake fields: Application to the ATF photoelectron beam

    International Nuclear Information System (INIS)

    Parsa, Z.

    1991-01-01

    Laser driven photoelectron guns are of interest for use in new methods of accelerations, future development of Linear Colliders and new experiments such as Free Electron laser (IFEL). Such guns are potential source of low emittance-high current and short bunch length electron beams, where the emitted electrons are accelerated quickly to a relativistic energy by a strong rf, electric field in the cavity. We present a brief overview of the beam dynamic studies, e.g. emittance for the Brookhaven National Laboratory (BNL) ATF high brightness photocathode radio frequency gun (now in operation), and show the effects of the rf, Space Charge, and Wake fields on the photoelectrons. 4 refs., 7 figs

  8. Simulations of beam emittance growth from the collectiverelaxation of space-charge nonuniformities

    Energy Technology Data Exchange (ETDEWEB)

    Lund, Steven M.; Grote, David P.; Davidson, Ronald C.

    2004-05-01

    Beams injected into a linear focusing channel typically have some degree of space-charge nonuniformity. For unbunched beams with high space-charge intensity propagating in linear focusing channels, Debye screening of self-field interactions tends to make the transverse density profile flat. An injected particle distribution with a large systematic charge nonuniformity will generally be far from an equilibrium of the focusing channel and the initial condition will launch a broad spectrum of collective modes. These modes can phase-mix and experience nonlinear interactions which result in an effective relaxation to a more thermal-equilibrium-like distribution characterized by a uniform density profile. This relaxation transfers self-field energy from the initial space-charge nonuniformity to the local particle temperature, thereby increasing beam phase space area (emittance growth). Here they employ two-dimensional electrostatic particle in cell (PIC) simulations to investigate the effects of initial transverse space-charge nonuniformities on the equality of beams with high space-charge intensity propagating in a continuous focusing channel. Results are compared to theoretical bounds of emittance growth developed in previous studies. Consistent with earlier theory, it is found that a high degree of initial distribution nonuniformity can be tolerated with only modest emittance growth and that beam control can be maintained. The simulations also provide information on the rate of relaxation and characteristic levels of fluctuations in the relaxed states. This research suggests that a surprising degree of initial space-charge nonuniformity can be tolerated in practical intense beam experiments.

  9. Magnetic Waveform Measurements of the PS Injection Kicker KFA45 and Future Emittance Growth Estimates

    CERN Document Server

    Forte, Vincenzo; Ferrero Colomo, Alvaro; CERN. Geneva. ATS Department

    2018-01-01

    In the framework of the LHC Injectors Upgrade (LIU) project [1], this document summarises the beam-based measurement of the magnetic waveform of the PS injection kicker KFA45 [2], from data collected during several Machine Development (MD) sessions in 2016 and 2017. In the first part of the document, the measurement methodology is introduced and the results presented and compared with the specification required for a clean transfer of the bunches coming from the PSB after the upgrade. These measurements represent, to date, the only way to reconstruct the magnetic waveform. In the second part, kicker magnetic waveform PSpice®[3] simulations are compared and tuned to the measurements. Finally the simulated (validated through measurements) waveforms are used to estimate the future expected emittance growth for the different PS injection schemes, both for (LIU target) LHC and fixed target beams.

  10. A laboratory goniometer system for measuring reflectance and emittance anisotropy.

    Science.gov (United States)

    Roosjen, Peter P J; Clevers, Jan G P W; Bartholomeus, Harm M; Schaepman, Michael E; Schaepman-Strub, Gabriela; Jalink, Henk; van der Schoor, Rob; de Jong, Arjan

    2012-12-13

    In this paper, a laboratory goniometer system for performing multi-angular measurements under controlled illumination conditions is described. A commercially available robotic arm enables the acquisition of a large number of measurements over the full hemisphere within a short time span making it much faster than other goniometers. In addition, the presented set-up enables assessment of anisotropic reflectance and emittance behaviour of soils, leaves and small canopies. Mounting a spectrometer enables acquisition of either hemispherical measurements or measurements in the horizontal plane. Mounting a thermal camera allows directional observations of the thermal emittance. This paper also presents three showcases of these different measurement set-ups in order to illustrate its possibilities. Finally, suggestions for applying this instrument and for future research directions are given, including linking the measured reflectance anisotropy with physically-based anisotropy models on the one hand and combining them with field goniometry measurements for joint analysis with remote sensing data on the other hand. The speed and flexibility of the system offer a large added value to the existing pool of laboratory goniometers.

  11. Linac4 Low Energy Beam Measurements with Negative Hydrogen

    CERN Document Server

    Scrivens, R; Crettiez, O; Dimov, V; Gerard, D; Granemann Souza, E; Guida, R; Hansen, J; Lallement, J B; Lettry, J; Lombardi, A; Midttun, O; Pasquino, C; Raich, U; Riffaud, B; Roncarolo, F; Valerio-Lizarraga, C A; Wallner, J; Yarmohammadi Satri, M; Zickler, T

    2014-01-01

    Linac4, a 160 MeV normal-conducting H- linear accelerator, is the first step in the upgrade of the beam intensity available from the LHC proton injectors at CERN. The Linac4 Low Energy Beam Transport (LEBT) line from the pulsed 2 MHz RF driven ion source, to the 352 MHz RFQ has been built and installed at a test stand, and has been used to transport and match to the RFQ a pulsed 14 mA H- beam at 45 keV. A temporary slit-and-grid emittance measurement system has been put in place to characterize the beam delivered to the RFQ. In this paper a description of the LEBT and its beam diagnostics is given, and the results of beam emittance measurements and beam transmission measurements through the RFQ are compared with the expectation from simulations.

  12. Beam based measurement of beam position monitor electrode gains

    Directory of Open Access Journals (Sweden)

    D. L. Rubin

    2010-09-01

    Full Text Available Low emittance tuning at the Cornell Electron Storage Ring (CESR test accelerator depends on precision measurement of vertical dispersion and transverse coupling. The CESR beam position monitors (BPMs consist of four button electrodes, instrumented with electronics that allow acquisition of turn-by-turn data. The response to the beam will vary among the four electrodes due to differences in electronic gain and/or misalignment. This variation in the response of the BPM electrodes will couple real horizontal offset to apparent vertical position, and introduce spurious measurements of coupling and vertical dispersion. To alleviate this systematic effect, a beam based technique to measure the relative response of the four electrodes has been developed. With typical CESR parameters, simulations show that turn-by-turn BPM data can be used to determine electrode gains to within ∼0.1%.

  13. Compact Measurement Station for Low Energy Proton Beams

    CERN Document Server

    Yildiz, H.

    2017-02-24

    A compact, remote controlled, cost efficient diagnostic station has been developed to measure the charge, the profile and the emittance for low energy proton beams. It has been installed and tested in the proton beam line of the Project Prometheus at SANAEM of the Turkish Atomic Energy Authority.

  14. Specific Emitter Identification Based on the Natural Measure

    Directory of Open Access Journals (Sweden)

    Yongqiang Jia

    2017-03-01

    Full Text Available Specific emitter identification (SEI techniques are often used in civilian and military spectrum-management operations, and they are also applied to support the security and authentication of wireless communication. In this letter, a new SEI method based on the natural measure of the one-dimensional component of the chaotic system is proposed. We find that the natural measures of the one-dimensional components of higher dimensional systems exist and that they are quite diverse for different systems. Based on this principle, the natural measure is used as an RF fingerprint in this letter. The natural measure can solve the problems caused by a small amount of data and a low sample rate. The Kullback–Leibler divergence is used to quantify the difference between the natural measures obtained from diverse emitters and classify them. The data obtained from real application are exploited to test the validity of the proposed method. Experimental results show that the proposed method is not only easy to operate, but also quite effective, even though the amount of data is small and the sample rate is low.

  15. Ugrades of beam diagnostics in support of emittance-exchange experiments at the Fermilab A0 photoinjector

    Energy Technology Data Exchange (ETDEWEB)

    Lumpkin, A.H.; Johnson, A.S.; Ruan, J.; Santucci, J.; Sun, Y.-E.; Thurman-Keup, R.; Edwards, H.; /Fermilab

    2011-01-01

    The possibility of using electron beam phase space manipulations to support a free-electron laser accelerator design optimization has motivated our research. An ongoing program demonstrating the exchange of transverse horizontal and longitudinal emittances at the Fermilab A0 photoinjector has benefited recently from the upgrade of several of the key diagnostics stations. Accurate measurements of these properties upstream and downstream of the exchanger beamline are needed. Improvements in the screen resolution term and reduced impact of the optical system's depth-of-focus by using YAG:Ce single crystals normal to the beam direction will be described. The requirement to measure small energy spreads (<10 keV) in the spectrometer and the exchange process which resulted in bunch lengths less than 500 fs led to other diagnostics performance adjustments and upgrades as well. A longitudinal to transverse exchange example is also reported.

  16. Emittance investigation of RF photo-injector

    CERN Document Server

    Yang Mao Rong; Li Zheng; Li Ming; Xu Zhou

    2002-01-01

    A high-power laser beam illuminates a photocathode surface placed on an end wall of an RF cavity. The emitted electrons are accelerated immediately to a relativistic energy by the strong RF find in the cavity. But space charge effect induces beam emittance growth especially near the cathode where the electrons are still nonrelativistic. The author analyzes the factors which lead the transverse emittance growth and method how to resolve this problem. After introducing solenoidal focusing near the photocathode, the beam emittance growth is suppressed dramatically. The beam emittance is given also after compensation and simulation results. The measurements show these results are coincident

  17. On the Emittance dependence on anode morphology of laser induced ion beams

    International Nuclear Information System (INIS)

    Velardi, L; Delle Side, D; Nassisi, V

    2014-01-01

    In this work, we studied the characteristics of ion beams generated by PLATONE accelerator in different anode configurations. The accelerator is a laser ion source with two gaps which accelerate the ions in cascade. The laser is an excimer KrF able to work at irradiances of 10 8 -10 10 W/cm 2 . The target ablated was disk of Cu. The accelerating voltage applied in this work was 60 kV. The emittance evaluation was performed by the pepper pot method utilising radio-chromic films, EBT Gafchromic, as sensible targets. The study was performed by varying the geometric configuration of the anode (the extracting electrode), modifying the hole morphology. A plane and curved grids were mounted in order to change the extraction configuration. The results were compared with the ones obtained with the extraction hole without any grid. For the normalized emittance the lowest value found was 0.20 π mm mrad.

  18. Development and investigation of finite energy spread and improved emittance relativistic electron beams

    International Nuclear Information System (INIS)

    Fink, J.; Schilling, H.B.; Schumacher, U.

    1979-07-01

    The experiments with a divided cathode in an electron beam gun, one half of which is connected via a resistor with the high voltage terminal, lead to the generation of a low emittance electron beam with instantaneously two different energies which is suitable for suppression of collective instabilities in an electron ring accelerator. The energy difference can be varied up to 100 keV proportional to the resistance, and the sub-currents are equal. The beam parts are well separated and focussed at the injection area of the compressor, and their radial distance is about equal to the radial difference of the corresponding closed orbits, such that electron ring formation with minimum radial betatron oscillations should be possible. (orig.)

  19. Low emittance design of the electron gun and the focusing channel of the Compact Linear Collider drive beam

    Directory of Open Access Journals (Sweden)

    M. Dayyani Kelisani

    2017-04-01

    Full Text Available For the Compact Linear Collider project at CERN, the power for the main linacs is extracted from a drive beam generated from a high current electron source. The design of the electron source and its subsequent focusing channel has a great impact on the beam dynamic considerations of the drive beam. We report the design of a thermionic electron source and the subsequent focusing channels with the goal of production of a high quality beam with a very small emittance.

  20. Measurement of the microwave emitter's inhomogeneity using optical fiber DTS

    Science.gov (United States)

    Jaros, Jakub; Papes, Martin; Liner, Andrej; Vašinek, Vladimir; Smira, Pavel; Nasswettrova, Andrea; Cubik, Jakub; Kepak, Stanislav

    2014-06-01

    Researcher's teams were dealing with the microwave emitter's inhomogeneity problem since the microwaves were used. One possible way, how to measure electromagnetic field is the measurement on inhomogeneous temperature distribution on the irradiated sample, which can cause problems as in other material processing, so in the undesirable change of properties and even security. Inhomogeneity of electromagnetic field is specific by creating spots with higher or lower temperature called "hot spots". This inhomogeneity strongly affects the temperature distribution in the cross section of the material and its resultant heating. Given the impossibility of using classical electronic devices with metal temperature sensors were various indirect methods used in the past. This paper deals with experimental measurement of the microwave emitter's inhomogeneity (2.45 GHz) using the optical fiber DTS. The greatest advantage of this sensor system is just in using of the optical fiber (electromagnetic resistance, small size, safety using in inflammable and explosive area, easy installation). Due to these properties of the optical fiber sensor it's possible to measure the temperature of the sample in real time. These sensor are able to measure the temperature along the fiber, in some cases they use nonlinear effect in optical fiber (Raman nonlinear effect). The verification of non-homogeneity consists in experimental measuring of the temperature distribution within the wooden sample. The method is based on heat exchange in an isolated system where wooden sample serves as an absorber of the irradiated energy. To identify locations with different power density was used DTS system, based on nonlinear phenomena in optical fibers.

  1. Accuracy determination of the CERN Linac4 emittance measurements at the test bench for 3 and 12 Mev

    CERN Document Server

    Roncarolo, F; Bravin, E; Raich, U

    2010-01-01

    The CERN LINAC4 commissioning will start in 2011, at first in a laboratory test stand where the 45 KeV Hsource is already installed and presently tested, and later in the LINAC4 tunnel. A movable diagnostics bench will be equipped with the necessary sensors capable of characterizing the H- beam in different stages, from 3 MeV up to the first DTL tank at 12 MeV. In this paper we will discuss the accuracy of the transverse emittance measurement that will be performed with the slit-grid method. The system’s mechanical and geometric parameters have been determined in order to achieve the required resolution and sensitivity. Space charge effects during the beam transfer from the slit to the grid and scattering effects at the slit have been considered to determine the overall emittance measurement accuracy.

  2. Ultrafast transmission electron microscopy using a laser-driven field emitter: Femtosecond resolution with a high coherence electron beam

    Energy Technology Data Exchange (ETDEWEB)

    Feist, Armin; Bach, Nora; Rubiano da Silva, Nara; Danz, Thomas; Möller, Marcel; Priebe, Katharina E.; Domröse, Till; Gatzmann, J. Gregor; Rost, Stefan; Schauss, Jakob; Strauch, Stefanie; Bormann, Reiner; Sivis, Murat; Schäfer, Sascha, E-mail: sascha.schaefer@phys.uni-goettingen.de; Ropers, Claus, E-mail: claus.ropers@uni-goettingen.de

    2017-05-15

    We present the development of the first ultrafast transmission electron microscope (UTEM) driven by localized photoemission from a field emitter cathode. We describe the implementation of the instrument, the photoemitter concept and the quantitative electron beam parameters achieved. Establishing a new source for ultrafast TEM, the Göttingen UTEM employs nano-localized linear photoemission from a Schottky emitter, which enables operation with freely tunable temporal structure, from continuous wave to femtosecond pulsed mode. Using this emission mechanism, we achieve record pulse properties in ultrafast electron microscopy of 9 Å focused beam diameter, 200 fs pulse duration and 0.6 eV energy width. We illustrate the possibility to conduct ultrafast imaging, diffraction, holography and spectroscopy with this instrument and also discuss opportunities to harness quantum coherent interactions between intense laser fields and free-electron beams. - Highlights: • First implementation of an ultrafast TEM employing a nanoscale photocathode. • Localized single photon-photoemission from nanoscopic field emitter yields low emittance ultrashort electron pulses. • Electron pulses focused down to ~9 Å, with a duration of 200 fs and an energy width of 0.6 eV are demonstrated. • Quantitative characterization of ultrafast electron gun emittance and brightness. • A range of applications of high coherence ultrashort electron pulses is shown.

  3. Drift tube alignment and beam emittance codes in use at the SuperHILAC

    International Nuclear Information System (INIS)

    Spence, D.A.

    1974-01-01

    Two Fortran-IV codes in use at the SuperHILAC are of significant value in optimizing the geometry of the accelerator and in evaluating the performance of the heavy ion beams. The first routine described is used to determine the existing root mean square deviation of the 210 internal drift tube quadrupoles fitted to a straight line or to a second-order quadratic. It then predicts the minimum number of drift tubes, and their identities, to be moved in order to attain a user-elected margin of error fit. Brief mention is made of the pulsed-wire alignment technique for the quadrupole positioning. The second program described is part of a data system which utilizes a PDP-8/I as a control device for the manipulation of beam-scanning hardware and a CDC-6600 in an off-line interactive mode which gives the user maximum versatility in treating the raw data and displaying the results of calculations. The code portrays the transverse beam emittance figures and their transmission through the accelerator and transport lines. Also discussed are future plans which include on-line data reduction and CRT display by the PDP-8/I to enable the operators to optimize the tuning of the HILAC. (U.S.)

  4. A Novel Location-Awareness Method Using CubeSats for Locating the Spot Beam Emitters of Geostationary Communications Satellites

    Directory of Open Access Journals (Sweden)

    Weicai Yang

    2018-01-01

    Full Text Available As more spacecraft are launched into the Geostationary Earth Orbit (GEO belt, the possibility of fatal collisions or unnecessary interference between spacecraft increases. In this paper, a new location-awareness method that uses CubeSats is proposed to assist with radiofrequency (RF domain verification by means of awareness and identification of the positions of the spot beam emitters of communications satellites in geostationary orbit. By flying a CubeSat (or a constellation of CubeSats through the coverage area of a spot beam, the spot beam emitter’s position is identified and the spot beam’s pattern knowledge is characterized. The geometry, the equations of motion of the spacecraft, the measurement process, and the filtering equations in a location system are addressed with respect to the location methods investigated in this study. A realistic scenario in which a CubeSat receives signals from GEO communications satellites is simulated using the Systems Tool Kit (STK. The results of the simulation and the analysis presented in this study provide a thorough verification of the performance of the location-awareness method.

  5. Smith-Purcell experiment utilizing a field-emitter array cathode measurements of radiation

    CERN Document Server

    Ishizuka, H; Yokoo, K; Shimawaki, H; Hosono, A

    2001-01-01

    Smith-Purcell (SP) radiation at wavelengths of 350-750 nm was produced in a tabletop experiment using a field-emitter array (FEA) cathode. The electron gun was 5 cm long, and a 25 mmx25 mm holographic replica grating was placed behind the slit provided in the anode. A regulated DC power supply accelerated electron beams in excess of 10 mu A up to 45 keV, while a small Van de Graaff generator accelerated smaller currents to higher energies. The grating had a 0.556 mu m period, 30 deg. blaze and a 0.2 mu m thick aluminum coating. Spectral characteristics of the radiation were measured both manually and automatically; in the latter case, the spectrometer was driven by a stepping motor to scan the wavelength, and AD-converted signals from a photomultiplier tube were processed by a personal computer. The measurement, made at 80 deg. relative to the electron beam, showed good agreement with theoretical wavelengths of the SP radiation. Diffraction orders were -2 and -3 for beam energies higher than 45 keV, -3 to -5 ...

  6. Smith-Purcell experiment utilizing a field-emitter array cathode: measurements of radiation

    Science.gov (United States)

    Ishizuka, H.; Kawamura, Y.; Yokoo, K.; Shimawaki, H.; Hosono, A.

    2001-12-01

    Smith-Purcell (SP) radiation at wavelengths of 350-750 nm was produced in a tabletop experiment using a field-emitter array (FEA) cathode. The electron gun was 5 cm long, and a 25 mm×25 mm holographic replica grating was placed behind the slit provided in the anode. A regulated DC power supply accelerated electron beams in excess of 10 μA up to 45 keV, while a small Van de Graaff generator accelerated smaller currents to higher energies. The grating had a 0.556 μm period, 30° blaze and a 0.2 μm thick aluminum coating. Spectral characteristics of the radiation were measured both manually and automatically; in the latter case, the spectrometer was driven by a stepping motor to scan the wavelength, and AD-converted signals from a photomultiplier tube were processed by a personal computer. The measurement, made at 80° relative to the electron beam, showed good agreement with theoretical wavelengths of the SP radiation. Diffraction orders were -2 and -3 for beam energies higher than 45 keV, -3 to -5 at 15-25 keV, and -2 to -4 in between. The experiment has thus provided evidence for the practical applicability of FEAs to compact radiation sources.

  7. Smith-Purcell experiment utilizing a field-emitter array cathode: measurements of radiation

    International Nuclear Information System (INIS)

    Ishizuka, H.; Kawamura, Y.; Yokoo, K.; Shimawaki, H.; Hosono, A.

    2001-01-01

    Smith-Purcell (SP) radiation at wavelengths of 350-750 nm was produced in a tabletop experiment using a field-emitter array (FEA) cathode. The electron gun was 5 cm long, and a 25 mmx25 mm holographic replica grating was placed behind the slit provided in the anode. A regulated DC power supply accelerated electron beams in excess of 10 μA up to 45 keV, while a small Van de Graaff generator accelerated smaller currents to higher energies. The grating had a 0.556 μm period, 30 deg. blaze and a 0.2 μm thick aluminum coating. Spectral characteristics of the radiation were measured both manually and automatically; in the latter case, the spectrometer was driven by a stepping motor to scan the wavelength, and AD-converted signals from a photomultiplier tube were processed by a personal computer. The measurement, made at 80 deg. relative to the electron beam, showed good agreement with theoretical wavelengths of the SP radiation. Diffraction orders were -2 and -3 for beam energies higher than 45 keV, -3 to -5 at 15-25 keV, and -2 to -4 in between. The experiment has thus provided evidence for the practical applicability of FEAs to compact radiation sources

  8. Measurements of Transverse Emittance for RF Photocathode Gun at the PAL

    CERN Document Server

    Park Jang Ho; Park, Sung-Ju; Soo Ko In; Wang, Xijie; Woon Parc, Yong; Xiang, Dao

    2005-01-01

    A BNL GUN-IV type RF photo-cathode gun is under fabrication for use in the FIR (Far Infra-Red) facility being built at the Pohang Accelerator Laboratory (PAL). Performance test of the gun will include the measurement of transverse emittance profile along the longitudinal direction. Successful measurement of the emittance profile will provide powerful tool for the commissioning of the 4GLS (4th generation light source) injectors based on the emittance compensation principle. We are going to achieve this withthe use of pepper-pot based emittance meters that can be moved along the longitudinal direction. In this article, we present design considerations on the emittance meter with the resolution of 1 mm mrad.

  9. Emittance growth due to Tevatron flying wires

    Energy Technology Data Exchange (ETDEWEB)

    Syphers, M; Eddy, Nathan

    2004-06-01

    During Tevatron injection, Flying Wires have been used to measure the transverse beam size after each transfer from the Main Injector in order to deduce the transverse emittances of the proton and antiproton beams. This amounts to 36 + 9 = 45 flies of each of 3 wire systems, with an individual wire passing through each beam bunch twice during a single ''fly''. below they estimate the emittance growth induced by the interaction of the wires with the particles during these measurements. Changes of emittance from Flying Wire measurements conducted during three recent stores are compared with the estimations.

  10. High-precision half-life and branching-ratio measurements for superallowed Fermi β+ emitters at TRIUMF – ISAC

    Directory of Open Access Journals (Sweden)

    Laffoley A. T.

    2014-03-01

    Full Text Available A program of high-precision half-life and branching-ratio measurements for superallowed Fermi β emitters is being carried out at TRIUMF’s Isotope Separator and Accelerator (ISAC radioactive ion beam facility. Recent half-life measurements for the superallowed decays of 14O, 18Ne, and 26Alm, as well as branching-ratio measurements for 26Alm and 74Rb are reported. These results provide demanding tests of the Standard Model and the theoretical isospin symmetry breaking (ISB corrections in superallowed Fermi β decays.

  11. Ultrafast transmission electron microscopy using a laser-driven field emitter: Femtosecond resolution with a high coherence electron beam.

    Science.gov (United States)

    Feist, Armin; Bach, Nora; Rubiano da Silva, Nara; Danz, Thomas; Möller, Marcel; Priebe, Katharina E; Domröse, Till; Gatzmann, J Gregor; Rost, Stefan; Schauss, Jakob; Strauch, Stefanie; Bormann, Reiner; Sivis, Murat; Schäfer, Sascha; Ropers, Claus

    2017-05-01

    We present the development of the first ultrafast transmission electron microscope (UTEM) driven by localized photoemission from a field emitter cathode. We describe the implementation of the instrument, the photoemitter concept and the quantitative electron beam parameters achieved. Establishing a new source for ultrafast TEM, the Göttingen UTEM employs nano-localized linear photoemission from a Schottky emitter, which enables operation with freely tunable temporal structure, from continuous wave to femtosecond pulsed mode. Using this emission mechanism, we achieve record pulse properties in ultrafast electron microscopy of 9Å focused beam diameter, 200fs pulse duration and 0.6eV energy width. We illustrate the possibility to conduct ultrafast imaging, diffraction, holography and spectroscopy with this instrument and also discuss opportunities to harness quantum coherent interactions between intense laser fields and free-electron beams. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

  12. Simulation study of electron cloud induced instabilities and emittance growth for the CERN Large Hadron Collider proton beam

    CERN Document Server

    Benedetto, Elena; Schulte, Daniel; Rumolo, Giovanni

    2005-01-01

    The electron cloud may cause transverse single-bunch instabilities of proton beams such as those in the Large Hadron Collider (LHC) and the CERN Super Proton Synchrotron (SPS). We simulate these instabilities and the consequent emittance growth with the code HEADTAIL, which models the turn-by-turn interaction between the cloud and the beam. Recently some new features were added to the code, in particular, electric conducting boundary conditions at the chamber wall, transverse feedback, and variable beta functions. The sensitivity to several numerical parameters has been studied by varying the number of interaction points between the bunch and the cloud, the phase advance between them, and the number of macroparticles used to represent the protons and the electrons. We present simulation results for both LHC at injection and SPS with LHC-type beam, for different electron-cloud density levels, chromaticities, and bunch intensities. Two regimes with qualitatively different emittance growth are observed: above th...

  13. An experimental method for making spectral emittance and surface temperature measurements of opaque surfaces

    International Nuclear Information System (INIS)

    Moore, Travis J.; Jones, Matthew R.; Tree, Dale R.; Daniel Maynes, R.; Baxter, Larry L.

    2011-01-01

    An experimental procedure has been developed to make spectral emittance and temperature measurements. The spectral emittance of an object is calculated using measurements of the spectral emissive power and of the surface temperature of the object obtained using a Fourier transform infrared (FTIR) spectrometer. A calibration procedure is described in detail which accounts for the temperature dependence of the detector. The methods used to extract the spectral emissive power and surface temperature from measured infrared spectra were validated using a blackbody radiator at known temperatures. The average error in the measured spectral emittance was 2.1% and the average difference between the temperature inferred from the recorded spectra and the temperature indicated on the blackbody radiator was 1.2%. The method was used to measure the spectral emittance of oxidized copper at various temperatures.

  14. Transverse Beam Profile Measurements Using Optical Methods

    CERN Document Server

    Peters, A; Weiss, A; Bank, A

    2001-01-01

    Two different systems are currently under development at GSI's heavy ion facility to measure transverse beam profiles using optical emitters. At the GSI-LINAC for energies up to 15 MeV/u residual gas fluorescence is investigated for pulsed high current beams. The fluorescence of N2 is monitored by an image intensified CCD camera. For all ion species with energies above 50 MeV/u slowly extracted from the synchrotron SIS a classical viewing screen system is used. Three different target materials have been investigated and their behavior concerning efficiency, saturation and timing performance is evaluated. Both systems (will) use CCD cameras with a digital read out using the IEEE 1394 standard.

  15. Neutron beam measurement dosimetry

    International Nuclear Information System (INIS)

    Amaro, C.R.

    1995-01-01

    This report describes animal dosimetry studies and phantom measurements. During 1994, 12 dogs were irradiated at BMRR as part of a 4 fraction dose tolerance study. The animals were first infused with BSH and irradiated daily for 4 consecutive days. BNL irradiated 2 beagles as part of their dose tolerance study using BPA fructose. In addition, a dog at WSU was irradiated at BMRR after an infusion of BPA fructose. During 1994, the INEL BNCT dosimetry team measured neutron flux and gamma dose profiles in two phantoms exposed to the epithermal neutron beam at the BMRR. These measurements were performed as a preparatory step to the commencement of human clinical trials in progress at the BMRR

  16. Beam diffusion measurements using collimator scans in the LHC

    Science.gov (United States)

    Valentino, Gianluca; Aßmann, Ralph; Bruce, Roderik; Burkart, Florian; Previtali, Valentina; Redaelli, Stefano; Salvachua, Belen; Stancari, Giulio; Valishev, Alexander

    2013-02-01

    The time evolution of beam losses during a collimator scan provides information on halo diffusion and population. This is an essential input for machine performance characterization and for the design of collimation systems. Beam halo measurements in the CERN Large Hadron Collider were conducted through collimator scrapings in a dedicated beam study for the first time at 4 TeV. Four scans were performed with two collimators, in the vertical plane for beam 1 and horizontally for beam 2, before and after bringing the beams into collisions. Inward and outward steps were performed. A diffusion model was used to interpret the observed loss rate evolution in response to the collimator steps. With this technique, diffusion coefficients were estimated as a function of betatron oscillation amplitude from approximately 3 to 7 standard deviations of the transverse beam distribution. A comparison of halo diffusion and core emittance growth rates is also presented.

  17. Beam diffusion measurements using collimator scans in the LHC

    Directory of Open Access Journals (Sweden)

    Gianluca Valentino

    2013-02-01

    Full Text Available The time evolution of beam losses during a collimator scan provides information on halo diffusion and population. This is an essential input for machine performance characterization and for the design of collimation systems. Beam halo measurements in the CERN Large Hadron Collider were conducted through collimator scrapings in a dedicated beam study for the first time at 4 TeV. Four scans were performed with two collimators, in the vertical plane for beam 1 and horizontally for beam 2, before and after bringing the beams into collisions. Inward and outward steps were performed. A diffusion model was used to interpret the observed loss rate evolution in response to the collimator steps. With this technique, diffusion coefficients were estimated as a function of betatron oscillation amplitude from approximately 3 to 7 standard deviations of the transverse beam distribution. A comparison of halo diffusion and core emittance growth rates is also presented.

  18. Linac beam dynamics calculations for low-current large-emittance beams

    International Nuclear Information System (INIS)

    Swain, G.R.; Butler, H.S.

    1992-01-01

    The beam in PILAC, a superconducting linac for pions proposed at LAUFF, will have a lager momentum spread (7% dp/p) and occupy a larger transverse space (13 cm dia. bore) than is usual in high-beta linacs. To find the effects of this large phase space, a cavity element is being added to the MOTER code. With this addition, pions and other particles may be tracked through the injection line and the PILAC linac. In one option, the particles may be cell by cell through a multicell cavity using formulas. The formulas are derived by integrating the energy gain and transverse impulse from the fields in a cell along the path of the particle. What is new in this analysis is that the transverse momentum is considered to be a significant part of the total momentum. The effect of a difference in velocity from the design velocity of the structure is considered. In another option still under development, field information is specified, and the particles may be tracked by stepwise integration

  19. Emittance calculations for the Stanford Linear Collider injector

    International Nuclear Information System (INIS)

    Sheppard, J.C.; Clendenin, J.E.; Helm, R.H.; Lee, M.J.; Miller, R.H.; Blocker, C.A.

    1983-03-01

    A series of measurements have been performed to determine the emittance of the high intensity, single bunch beam that is to be injected into the Stanford Linear Collider. On-line computer programs were used to control the Linac for the purpose of data acquisition and to fit the data to a model in order to deduce the beam emittance. This paper will describe the method of emittance calculation and present some of the measurement results

  20. Beam property measurement of a 300-kV ion source test stand for a 1-MV electrostatic accelerator

    Science.gov (United States)

    Park, Sae-Hoon; Kim, Dae-Il; Kim, Yu-Seok

    2016-09-01

    The KOMAC (Korea Multi-purpose Accelerator Complex) has been developing a 300-kV ion source test stand for a 1-MV electrostatic accelerator for industrial purposes. A RF ion source was operated at 200 MHz with its matching circuit. The beam profile and emittance were measured behind an accelerating column to confirm the beam property from the RF ion source. The beam profile was measured at the end of the accelerating tube and at the beam dump by using a beam profile monitor (BPM) and wire scanner. An Allison-type emittance scanner was installed behind the beam profile monitor (BPM) to measure the beam density in phase space. The measurement results for the beam profile and emittance are presented in this paper.

  1. MEASUREMENTS OF INTRA-BEAM SCATTERING GROWTH TIMES WITH GOLD BEAM BELOW TRANSITION IN RHIC

    International Nuclear Information System (INIS)

    FISCHER, W.; BAI, M.; BLASKIEWICZ, M.; BRENNAN, J.M.; CAMERON, P.; CONNOLLY, R.; LEHRACH, A.; PARZEN, G.; TEPIKIAN, S.; ZENO, K.; VAN ZEIJTS, J.

    2001-01-01

    While RHIC is filled with beam, bunches are stored for up to several minutes at the injection energy before acceleration starts. In gold operation, the RHIC injection energy is below transition. A bunch length increase, and correspondingly an increase in the longitudinal emittance, can lead to particle loss during transition crossing and rebucketing into the storage buckets. The longitudinal growth of gold beams in RHIC at injection is dominated by intra-beam scattering. Measurements of longitudinal growth times are presented and compared with computations

  2. Self-consistent simulation of the CSR effect on beam emittance

    International Nuclear Information System (INIS)

    Li, R.

    1999-01-01

    When a microbunch with high charge traverses a curved trajectory, the curvature-induced Coherent Synchrotron Radiation (CSR) and space-charge forces may cause serious emittance degradation. Earlier analyses based on rigid-line charge model are helpful in understanding the mechanism of this curvature-induced bunch self-interaction. In reality, however, the bunch has finite transverse size and its dynamics respond to the CSR force. In this paper, we present the first self-consistent simulation for the study of the impact of CSR on beam optics. With the bunch represented by a set of macroparticles, the dynamics of the bunch under the influence of the CSR force are simulated, where the CSR force in turn depends on the history of bunch charge distribution and current density in accordance to causality. This simulation is bench-marked with previous analytical results for a rigid-line bunch. The algorithm applied in the simulation will be presented, along with the simulation results obtained for bending systems in the Jefferson Lab FEL lattice

  3. Emittance Growth during Bunch Compression in the CTF-II

    Energy Technology Data Exchange (ETDEWEB)

    Raubenheimer, Tor O

    1999-02-26

    Measurements of the beam emittance during bunch compression in the CLIC Test Facility (CTF-II) are described. The measurements were made with different beam charges and different energy correlations versus the bunch compressor settings which were varied from no compression through the point of full compression and to over-compression. Significant increases in the beam emittance were observed with the maximum emittance occurring near the point of full (maximal) compression. Finally, evaluation of possible emittance dilution mechanisms indicate that coherent synchrotron radiation was the most likely cause.

  4. Emittance Growth during Bunch Compression in the CTF-II

    International Nuclear Information System (INIS)

    Raubenheimer, Tor O.

    1999-01-01

    Measurements of the beam emittance during bunch compression in the CLIC Test Facility (CTF-II) are described. The measurements were made with different beam charges and different energy correlations versus the bunch compressor settings which were varied from no compression through the point of full compression and to over-compression. Significant increases in the beam emittance were observed with the maximum emittance occurring near the point of full (maximal) compression. Finally, evaluation of possible emittance dilution mechanisms indicate that coherent synchrotron radiation was the most likely cause

  5. Feasibility of optical diffraction radiation for a non-invasive low-emittance beam diagnostics

    CERN Document Server

    Urakawa, J; Kubo, K; Kuroda, S; Terunuma, N; Kuriki, M; Okugi, T; Naito, T; Araki, S; Potylitsin, A P; Naumenko, G A; Karataev, P; Potylitsyna, N A; Vnukov, I; Hirose, T; Hamatsu, R; Muto, T; Ikezawa, M; Shibata, Y

    2001-01-01

    A 'proof-of-principle' experiment on the optical diffraction radiation (ODR) as a single-pulse beam profile monitor is planned using an electron beam extracted from the KEK-ATF damping ring. The main goals of this experiment are the following: (i) To measure the yield and the angular distributions of the optical diffraction radiation from a large-size target at different wavelengths, impact parameters and beam characteristics for a comparison with analogous characteristics of optical transition radiation from a foil with identical optical parameters and for a verification of the model assumption (perfectly conducting semi-infinite target). (ii) To investigate the ODR angular distributions from a tilted target with a slit for observing the interference effects. (iii) To compare the results obtained by simulations based on classical approaches, taking into account the optical characteristics of the equipment and the beam parameters. (iv) To estimate the prospects of using ODR as a new non-invasive tool for ultr...

  6. Measurements and analysis of a high-brightness electron beam collimated in a magnetic bunch compressor

    Science.gov (United States)

    Zhou, F.; Bane, K.; Ding, Y.; Huang, Z.; Loos, H.; Raubenheimer, T.

    2015-05-01

    A collimator located in a magnetic bunch compressor of a linear accelerator driven x-ray free electron laser has many potential applications, such as the removal of horns in the current distribution, the generation of ultrashort beams, and as a diagnostic of the beam slice emittance. Collective effects, however, are a major concern in applying the technique. Systematic measurements of emittance and analysis were performed using a collimator in the first bunch compressor of the Linac Coherent Light Source (LCLS). In the nominal, undercompressed configuration using the collimator we find that the y emittance (nonbending plane) is not increased, and the x emittance (in the bending plane) is increased by about 25%, in comparison to the injector emittance. From the analysis we conclude that the parasitic effects associated with this method are dominated by coherent synchrotron radiation (CSR), which causes a "systematic error" for measuring slice emittance at the bending plane using the collimation method. In general, we find good agreement between the measurements and simulations including CSR. However, for overcompressed beams at smaller collimator gaps, an extra emittance increase is found that does not agree with 1D simulations and is not understood.

  7. Total hemispherical emittance measured at high temperatures by the calorimetric method

    International Nuclear Information System (INIS)

    DiFilippo, F.; Mirtich, M.J.; Banks, B.A.; Stidham, C.; Kussmaul, M.

    1994-01-01

    A calorimetric vacuum emissometer (CVE) capable of measuring total hemispherical emittance of surfaces at elevated temperatures was designed, built, and tested. Several materials with a wide range of emittances were measured in the CVE between 773 to 923 K. These results were compared to values calculated from spectral emittance curves measured in a room temperature Hohlraum reflectometer and in an open-air elevated temperature emissometer. The results differed by as much as 0.2 for some materials but were in closer agreement for the more highly-emitting, diffuse-reflecting samples. The differences were attributed to temperature, atmospheric, and directional effects, and errors in the Hohlraum and emissometer measurements (± 5 percent). The probable error of the CVE measurements was typically less than 1 percent

  8. Beam-on imaging of short-lived positron emitters during proton therapy

    Science.gov (United States)

    Buitenhuis, H. J. T.; Diblen, F.; Brzezinski, K. W.; Brandenburg, S.; Dendooven, P.

    2017-06-01

    In vivo dose delivery verification in proton therapy can be performed by positron emission tomography (PET) of the positron-emitting nuclei produced by the proton beam in the patient. A PET scanner installed in the treatment position of a proton therapy facility that takes data with the beam on will see very short-lived nuclides as well as longer-lived nuclides. The most important short-lived nuclide for proton therapy is 12N (Dendooven et al 2015 Phys. Med. Biol. 60 8923-47), which has a half-life of 11 ms. The results of a proof-of-principle experiment of beam-on PET imaging of short-lived 12N nuclei are presented. The Philips Digital Photon Counting Module TEK PET system was used, which is based on LYSO scintillators mounted on digital SiPM photosensors. A 90 MeV proton beam from the cyclotron at KVI-CART was used to investigate the energy and time spectra of PET coincidences during beam-on. Events coinciding with proton bunches, such as prompt gamma rays, were removed from the data via an anti-coincidence filter with the cyclotron RF. The resulting energy spectrum allowed good identification of the 511 keV PET counts during beam-on. A method was developed to subtract the long-lived background from the 12N image by introducing a beam-off period into the cyclotron beam time structure. We measured 2D images and 1D profiles of the 12N distribution. A range shift of 5 mm was measured as 6  ±  3 mm using the 12N profile. A larger, more efficient, PET system with a higher data throughput capability will allow beam-on 12N PET imaging of single spots in the distal layer of an irradiation with an increased signal-to-background ratio and thus better accuracy. A simulation shows that a large dual panel scanner, which images a single spot directly after it is delivered, can measure a 5 mm range shift with millimeter accuracy: 5.5  ±  1.1 mm for 1  ×  108 protons and 5.2  ±  0.5 mm for 5  ×  108 protons. This makes

  9. Longitudinal Beam measurements at the LHC: The LHC Beam Quality Monitor

    CERN Document Server

    Papotti, G; Follin, F; Wehrle, U

    2011-01-01

    The LHC Beam Quality Monitor is a system that measures individual bunch lengths and positions, similarly to the twin system SPS Beam Quality Monitor, from which it was derived. The pattern verification that the system provides is vital during the injection process to verify the correctness of the injected pattern, while the bunch length measurement is fed back to control the longitudinal emittance blow up performed during the energy ramp and provides a general indication of the health of the RF system. The algorithms used, the hardware implementation and the system integration in the LHC control infrastructure are presented in this paper, along with possible improvements.

  10. Refined beam measurements on the SNS H- injector

    Science.gov (United States)

    Han, B. X.; Welton, R. F.; Murray, S. N.; Pennisi, T. R.; Santana, M.; Stinson, C. M.; Stockli, M. P.

    2017-08-01

    The H- injector for the SNS RFQ accelerator consists of an RF-driven, Cs-enhanced H- ion source and a compact, two-lens electrostatic LEBT. The LEBT output and the RFQ input beam current are measured by deflecting the beam on to an annular plate at the RFQ entrance. Our method and procedure have recently been refined to improve the measurement reliability and accuracy. The new measurements suggest that earlier measurements tended to underestimate the currents by 0-2 mA, but essentially confirm H- beam currents of 50-60 mA being injected into the RFQ. Emittance measurements conducted on a test stand featuring essentially the same H- injector setup show that the normalized rms emittance with 0.5% threshold (99% inclusion of the total beam) is in a range of 0.25-0.4 mm.mrad for a 50-60 mA beam. The RFQ output current is monitored with a BCM toroid. Measurements as well as simulations with the PARMTEQ code indicate an underperforming transmission of the RFQ since around 2012.

  11. Development of Stripline Kickers for Low Emittance Rings: Application to the Beam Extraction Kicker for CLIC Damping Rings

    CERN Document Server

    AUTHOR|(SzGeCERN)728476; Toral Fernandez, Fernando

    In the framework of the design study of Future Linear Colliders, the Compact Linear Collider (CLIC) aims for electron-positron collisions with high luminosity at a nominal centre-of-mass energy of 3 TeV. To achieve the luminosity requirements, Pre-Damping Rings (PDRs) and Damping Rings (DRs) are required: they reduce the beam emittance before the beam is accelerated in the main linac. Several injection and extraction systems are needed to inject and extract the beam from the PDRs and DRs. The work of this Thesis consists of the design, fabrication and laboratory tests of the first stripline kicker prototype for beam extraction from the CLIC DRs, although the methodology proposed can be extended to stripline kickers for any low emittance ring. The excellent field homogeneity required, as well as a good transmission of the high voltage pulse through the electrodes, has been achieved by choosing a novel electrode shape. With this new geometry, it has been possible to benefit from all the advantages that the most...

  12. Calculating emittance for Gaussian and Non-Gaussian distributions by the method of correlations for slits

    International Nuclear Information System (INIS)

    Tan, Cheng-Yang; Fermilab

    2006-01-01

    One common way for measuring the emittance of an electron beam is with the slits method. The usual approach for analyzing the data is to calculate an emittance that is a subset of the parent emittance. This paper shows an alternative way by using the method of correlations which ties the parameters derived from the beamlets to the actual parameters of the parent emittance. For parent distributions that are Gaussian, this method yields exact results. For non-Gaussian beam distributions, this method yields an effective emittance that can serve as a yardstick for emittance comparisons

  13. Semiconductor emitter based 32-channel spectrophotometer module for real-time process measurements

    Science.gov (United States)

    Keranen, Heimo; Malinen, Jouko

    1990-08-01

    A new type of semiconductor emitter based multichannel spectrophotometer has been designed and tested. The spectrophotometer consists of a small electrically conirolled narrow band light source an optical receiver and microprocessor electronics for data processing. The light source is based on a 32-element GaAs and GaAIAs LED chip array which is connected to a diffraction grating and feedback optics. The source is capable of emitting intensity-stabilized single-beam narrow band light pulses. The wavelength of the light pulse can be selected by the electronics without using any moving parts. The optical mechanical and optoelectronic parts of the source have been integrated to form a compact hybrid construction. Main characteristics have been tested with an experimental 32-channel spectrophotometer designed for the wavelength range 810 nm - 1060 nm. Measured wavelength half-power bandwidths are 8 nm and channel separation is 7. 5 nm. A single spectrum scan can be recorded in 8 ms. 64 scans are averaged by the microprocessor electronics and data is transferred to a PC for a multicomponent spectrum analysis program. Output light power level is better than i05 times the averaged detector noise level. The wavelength range used is optimized for near infrared transmittance (NIT) analysis of agricultural products. 1.

  14. Noninterceptive transverse-beam measurements

    International Nuclear Information System (INIS)

    Chamberlin, D.D.; Minerbo, G.N.; Mottershead, C.T.

    1981-01-01

    Totally noninterceptive techniques for accurate measurement of transverse beam distributions are required for high-current continuous wave (cw) linacs, such as the Fusion Materials Irradiation Test (FMIT) accelerator. Sensors responding to visible radiation from beam interactions with residual gas and computer algorithms reconstructing spatial and phase space distributions have been implemented. This paper reports on early measurements of the beam from the injector of the prototype FMIT facility at Los Alamos. The first section indicates hardware setup and performance whereas the second section describes the data-processing software. The third section outlines the resultant measurements and further developments are discussed in the fourth section

  15. Double Emittance Exchanger as a Bunch Compressor for the MaRIE XFEL electron beam line at 1GeV

    Energy Technology Data Exchange (ETDEWEB)

    Malyzhenkov, Alexander [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Northern Illinois Univ., DeKalb, IL (United States); Yampolsky, Nikolai [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Carlsten, Bruce Eric [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-09-22

    We demonstrate an alternative realization of a bunch compressor (specifically the second bunch compressor for the MaRIE XFEL beamline, 1GeV electron energy) using a double emittance exchanger (EEX) and a telescope in the transverse phase space.We compare our results with a traditional bunch compressor realized via chicane, taking into account the nonlinear dynamics, Coherent Synchrotron Radiation (CSR) and Space Charge (SC) effects. In particular, we use the Elegant code for tracking particles through the beam line and analyze the eigen-emittances evolution to separate the influence of the CSR/SC effects from the nonlinear dynamics effects. We optimize the scheme parameters to reach a desirable compression factor and minimize the emittance growth. We observe dominant CSR-effects in our scheme resulting in critical emittance growth and introduce alternative version of an emittance exchanger with a reduced number of bending magnets to minimize the impact of CSR effects.

  16. Using Spread Spectrum Transform for Fast and Robust Simultaneous Measurement in Active Sensors with Multiple Emitters

    DEFF Research Database (Denmark)

    Harbo, Anders La-Cour; Stoustrup, Jakob

    2002-01-01

    We present a signal processing algorithm for making robust and simultaneous measurements in an active sensor, which has one or more emitters and a receiver, and which employs some sort of signal processing hardware. Robustness means low sensitivity to time and frequency localized disturbances......, and to white noise. This is achieved partly by using a orthogonal spread spectrum transform for modulating the signals transmitted from the emitters to the receiver, and partly by using a number of transmission channels. The method is fast since the signals are short, and since the method does not rely......-cost active sensors....

  17. Coupling sections, emittance growth, and drift compensation in the use of bent solenoids as beam transport elements

    Directory of Open Access Journals (Sweden)

    J. Norem

    1999-05-01

    Full Text Available Bent solenoids can transmit charged particle beams while providing momentum dispersion. While less familiar than quadrupole and dipole systems, bent solenoids can produce superficially simple transport lines and large acceptance spectrometers for use at low energies. Design issues such as drift compensation and coupling sections between straight and bent solenoids are identified, and aberrations such as shears produced by perpendicular error fields are discussed. Examples are considered which provide the basis for the design of emittance exchange elements for the cooling system of a muon collider.

  18. Generation of energy bands in the electron beam with an asymmetric chicane-type emittance exchange beamline

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Bo-Cheng, E-mail: jiangbocheng@sinap.ac.cn; Zhao, Zhen-tang; Feng, Chao

    2014-11-11

    An asymmetric chicane-type transverse to longitudinal emittance exchange beam line is investigated and presented in this paper. This design is more feasible for existing machines due to its coaxial arrangement of the components and dispense of symmetric requirement of two doglegs compared to two-dogleg type one. By inserting quadrupoles between the dogleg and deflecting cavity, the dispersion can be amplified and hence the bending angle of the chicane is reduced with the same deflecting cavity parameters which will reduce the coherent synchrotron radiation effect.

  19. MD 400: LHC emittance growth in presence of an external source of noise during collision

    CERN Document Server

    Barranco Garcia, Javier; Pieloni, Tatiana; Tambasco, Claudia; Trad, Georges; Valuch, Daniel; Betz, Michael; Wendt, Manfred; Pojer, Mirko; Solfaroli Camillocci, Matteo; Salvachua Ferrando, Belen Maria; Fuchsberger, Kajetan; Albert, Markus; Qiang, Ji; CERN. Geneva. ATS Department

    2016-01-01

    The interplay between head-on beam-beam interaction and external sources of noise can be a significant source of emittance growth, especially when considering large beam-beam tune shifts as for the HL-LHC upgrade project. In this experiment the emittance growth of colliding bunches with different brightness and therefore different beam-beam parameters in the presence of an external white noise source with different amplitudes is measured for different gains of the transverse feedback.

  20. Source brightness and useful beam current of carbon nanotubes and other very small emitters

    NARCIS (Netherlands)

    Kruit, P.; Bezuijen, M.; Barth, J.E.

    2006-01-01

    The potential application of carbon nanotubes as electron sources in electron microscopes is analyzed. The resolution and probe current that can be obtained from a carbon nanotube emitter in a low-voltage scanning electron microscope are calculated and compared to the state of the art using Schottky

  1. A laboratory goniometer system for measuring reflectance and emittance anisotropy

    NARCIS (Netherlands)

    Roosjen, P.P.J.; Clevers, J.G.P.W.; Bartholomeus, H.; Schaepman, M.E.; Schaepman-Strub, G.; Jalink, H.; Schoor, van der R.; Jong, de A.

    2012-01-01

    In this paper, a laboratory goniometer system for performing multi-angular measurements under controlled illumination conditions is described. A commercially available robotic arm enables the acquisition of a large number of measurements over the full hemisphere within a short time span making it

  2. Alpha emitters activity measurement using the defined solid angle method

    International Nuclear Information System (INIS)

    Blanchis, P.

    1983-01-01

    The defined solid angle counting method can reach a very high accuracy, specially for heavy ions as alpha particles emitted by a radioactive source. The activity measurement of such sources with a relative uncertainty of the order of 0.01% is investigated. Such an accuracy is available only under suitable conditions: the radiation emitted by the source must be isotropic and all the particles emitted in the effective solid angle must be detected. The efficiency detection value must be equal to unity and phenomena such as absorption or scattering must be null. It is shown that corrections often become necessary. All parameters which can influence the measurements are studied [fr

  3. Transverse-emittance measurements on an S-band photocathode RF electron gun

    CERN Document Server

    Schmerge, J F; Clendenin, J E; Decker, Franz Josef; Dowell, D H; Gierman, S M; Limborg, C G; Murphy, B F

    2002-01-01

    Proposed fourth-generation light sources using SASE FELs to generate short pulse, coherent, X-rays require demonstration of high brightness electron sources. The gun test facility at SLAC was built to test high brightness sources for the proposed linac coherent light source at SLAC. The transverse-emittance measurements are made at nearly 30 MeV by measuring the spot size on a YAG screen using the quadrupole scan technique. The emittance was measured to vary from 1 to 3.5 mm mrad as the charge is increased from 50 to 350 pC using a laser pulse width of 2 ps FWHM. The measurements are in good agreement with simulation results using the LANL version of PARMELA.

  4. Design analysis and performance evaluation of a two-dimensional camera for accelerated positron-emitter beam injection by computer simulation

    International Nuclear Information System (INIS)

    Llacer, J.; Chatterjee, A.; Batho, E.K.; Poskanzer, J.A.

    1982-05-01

    The characteristics and design of a high-accuracy and high-sensitivity 2-dimensional camera for the measurement of the end-point of the trajectory of accelerated heavy ion beams of positron emitter isotopes are described. Computer simulation methods have been used in order to insure that the design would meet the demanding criteria of ability to obtain the location of the centroid of a point source in the X-Y plane with errors smaller than 1 mm, with an activity of 100 nanoCi, in a counting time of 5 sec or less. A computer program which can be developed into a general purpose analysis tool for a large number of positron emitter camera configurations is described in its essential parts. The validation of basic simulation results with simple measurements is reported, and the use of the program to generate simulated images which include important second order effects due to detector material, geometry, septa, etc. is demonstrated. Comparison between simulated images and initial results with the completed instrument shows that the desired specifications have been met

  5. Measurements of the Argonne Wakefield Accelerator's low charge, 4 MeV RF photocathode witness beam

    International Nuclear Information System (INIS)

    Power, J.

    1998-01-01

    The Argonne Wakefield Accelerator's (AWA) witness RF photocathode gun produced its first electron beam in April of 1996. We have characterized the charge, energy, emittance and bunch length of the witness beam over the last several months. The emittance Was measured by both a quad scan that fitted for space charge using an in house developed Mathematica routine and a pepper pot technique. The bunch length was measured by imaging Cherenkov light from a quartz plate to a Hamamatsu streak camera with 2 psec resolution. A beam energy of 3.9 Mev was measured with a 6 inch round pole spectrometer while a beam charge was measured with both an ICT and a Faraday Cup. Although the gun will normally be run at 100 pC it has produced charges from 10 pC to 4 nc. All results of the measurements to date are presented here

  6. Analysis of measured radar data for specific emitter identification

    CSIR Research Space (South Africa)

    Conning, M

    2010-05-01

    Full Text Available and can be used more efficiently to determine the exact times when a pulse starts and ends [3]. Other statistical methods are also available, as mentioned below. To determine the start of a signal, [4] and [5] used a variance fractal dimension... measure together with a Bayesian step change detector. Temporal, nonstationary signals’ fractal dimensions change over time. Multifractals can be used with such signals, e.g. radar pulses that have time-varying fractal dimensions [4], [6] and [7]. A...

  7. Longitudinal emittance blow-up and production of future LHC beams

    CERN Document Server

    Albright, S; Shaposhnikova, E

    2017-01-01

    During Long Shutdown 2 the RF systems of the PSB willbe replaced with broadband Finemet systems, there will alsobe an energy increase and many other modifications. Thisnote summarises studies that were done to investigate how tomeet the emittance requirements for the LIU-PSB baselineand a possible use of the broadband cavities to improve thecapture process.The LIU-PSB baseline requires longitudinal emittanceblow-up to 3 eVs with 205 ns bunch length at extraction. Thecurrent ferrite RF systems were used, with phase modulationof a high harmonic, to produce 2.8 eVs bunches with 220ns bunch length, as this is the largest that can currentlybe transferred to the PS. Larger emittances were possible,demonstrating the ability to reach the LIU-PSB baseline inthe future, which is confirmed in simulation.The broadband impedance of the Finemet was exploitedto allow RF voltage to be supplied on three harmonics (h=1,h=2, h=3), as opposed to the usual 2. For high intensitybeams this lead to an improved capture efficiency for...

  8. Linac3 LEBT beam measurements during the 2014-2015 Argon ion run

    CERN Document Server

    Bellodi, Giulia; Maintrot, Marc; Toivanen, Ville Aleksi; CERN. Geneva. ATS Department

    2016-01-01

    Between Spring 2014 and Spring 2015, LINAC3 delivered a beam of Argon ions. A campaign of beam studies was launched with the aim of better understanding the present limitations in the machine performance in the framework of the requested intensity goals as defined by the LHC Injectors Upgrade project. Measurements were mostly focused on beam characterization in the low energy part of Linac3 (LEBT), where performance in operation is mostly limited (in terms of beam transmission). Systematic quadrupole scans provided indirect measurement of the beam transverse emittance and were used as input to improve and refine the accelerator and beam description parameters used in simulations. IBSimu studies of beam formation and extraction at the source were interfaced with particle tracking with the 3D code PATH, and the resulting predictions found good validation in the beam measurements taken during this campaign.

  9. Determination of beta emitters (90Sr, 14C and 3H) in routine measurements using plastic scintillation beads

    International Nuclear Information System (INIS)

    Tarancon, A.; Garcia, J.F.; Rauret, G.

    2004-01-01

    Plastic scintillation has recently been shown to be a powerful alternative to liquid scintillation and Cherenkov techniques in radionuclide determination due to the good values obtained for the measurement parameters and the low amount of wastes generated. The present study evaluated the capability of plastic scintillation beads and polyethylene vials for routine measurements of beta emitters ( 90 Sr, 14 C, 3 H). Results show that high- and medium-energetic beta emitters can be quantified with relative errors less than 5% in low-activity aqueous samples, whereas low-energetic beta emitters can only be quantified in medium-activity samples

  10. Artificial collisions, entropy and emittance growth in computer simulations of intense beams

    Energy Technology Data Exchange (ETDEWEB)

    Boine-Frankenheim, O., E-mail: o.boine-frankenheim@gsi.de [Institut für Theorie Elektromagnetischer Felder (TEMF), Technische Universität Darmstadt, Schloßgartenstr. 8, 64289 Darmstadt (Germany); GSI Helmholtzzentrum für Schwerionenforschung GmbH, Planckstr. 1, 64291 Darmstadt (Germany); Hofmann, I. [Institut für Theorie Elektromagnetischer Felder (TEMF), Technische Universität Darmstadt, Schloßgartenstr. 8, 64289 Darmstadt (Germany); GSI Helmholtzzentrum für Schwerionenforschung GmbH, Planckstr. 1, 64291 Darmstadt (Germany); Struckmeier, J.; Appel, S. [GSI Helmholtzzentrum für Schwerionenforschung GmbH, Planckstr. 1, 64291 Darmstadt (Germany)

    2015-01-11

    Artificial collisions during particle tracking with self-consistent space charge lead to diffusion-like, numerical effects. The artificial collisions generate a stochastic noise spectrum. As a consequence the entropy and the emittance can grow along periodic focusing structures. The growth rates depend on the number of simulation macro-particles and on the space charge tune shifts. In our study we present analytical predictions for the numerical friction and diffusion in 2D simulations. For simple focusing structures we derive a relation between the friction coefficient and the entropy growth. The scaling of the friction coefficient with the macro-particle number and the space charge tune shift is obtained from 2D simulations and compared to the analytic predictions.

  11. Stability of an emittance-dominated sheet-electron beam in planar wiggler and periodic permanent magnet structures with natural focusing

    Directory of Open Access Journals (Sweden)

    B. E. Carlsten

    2005-06-01

    Full Text Available A sheet-beam traveling-wave amplifier has been proposed as a high-power generator of rf from 95 to 300 GHz, using a microfabricated rf slow-wave structure [Carlsten et al., IEEE Trans. Plasma Sci. 33, 85 (2005ITPSBD0093-381310.1109/TPS.2004.841172], for emerging radar and communications applications. The planar geometry of microfabrication technologies matches well with the nearly planar geometry of a sheet beam, and the greater allowable beam current leads to high-peak power, high-average power, and wide bandwidths. Simulations of nominal designs using a vane-loaded waveguide as the slow-wave structure have indicated gains in excess of 1   dB/mm, with extraction efficiencies greater than 20% at 95 GHz with a 120-kV, 20-A electron beam. We have identified stable sheet-beam formation and transport as the key enabling technology for this type of device. In this paper, we describe sheet-beam transport, for both wiggler and periodic permanent magnet (PPM magnetic field configurations, with natural (or single-plane focusing. For emittance-dominated transport, the transverse equation of motion reduces to a Mathieu equation, and to a modified Mathieu equation for a space-charge dominated beam. The space-charge dominated beam has less beam envelope ripple than an emittance-dominated beam, but they have similar stability thresholds (defined by where the beam ripple continues to grow without bound along the transport line, consistent with the threshold predicted by the Mathieu equation. Design limits are derived for an emittance-dominated beam based on the Mathieu stability threshold. The increased beam envelope ripple for emittance-dominated transport may impact these design limits, for some transport requirements. The stability of transport in a wiggler field is additionally compromised by the beam’s increased transverse motion. Stable sheet-beam transport with natural focusing is shown to be achievable for a 120-kV, 20-A, elliptical beam with

  12. High resolution spectrometry: how the analyzer and spectrometer performances and the beam emittance contribute to the results obtained

    International Nuclear Information System (INIS)

    Roussel, P.

    1984-01-01

    Using first order calculations derived for an achromatic system A) (deltaxsub(F)/deltaEsub(i)=0) or an optimised system O) (xsub(F) minima). It is shown that the final resolution measured in the local plane of the spectrometer depends only on the emittance of the accelerator and of the efficient area of the analyser exclusive of the properties of the spectrometer. The use of this result is only limited by higher order terms in the calculation or considerations out of this scope like target effects etc.. [fr

  13. Measurement of the tradeoff between intrinsic emittance and quantum efficiency from a NaKSb photocathode near threshold

    Energy Technology Data Exchange (ETDEWEB)

    Maxson, Jared, E-mail: jmm586@cornell.edu; Cultrera, Luca; Gulliford, Colwyn; Bazarov, Ivan [Cornell Laboratory for Accelerator-Based Sciences and Education, Cornell University, Ithaca, New York 14853 (United States)

    2015-06-08

    We measure the tradeoff between the quantum efficiency and intrinsic emittance from a NaKSb photocathode at three increasing wavelengths (635, 650, and 690 nm) at or below the energy of the bandgap plus the electron affinity, hν≤E{sub g}+E{sub a}. These measurements were performed using a high voltage dc gun for varied photocathode surface fields of 1.4−4.4 MV/m. Measurements of intrinsic emittance are performed using two different methods and were found to agree. At the longest wavelength available, 690 nm, the intrinsic emittance was 0.26 μm/mm-rms with a quantum efficiency of ∼10{sup −4}. The suitability of NaKSb emitting at threshold for various low emittance applications is discussed.

  14. Measurement of the tradeoff between intrinsic emittance and quantum efficiency from a NaKSb photocathode near threshold

    Science.gov (United States)

    Maxson, Jared; Cultrera, Luca; Gulliford, Colwyn; Bazarov, Ivan

    2015-06-01

    We measure the tradeoff between the quantum efficiency and intrinsic emittance from a NaKSb photocathode at three increasing wavelengths (635, 650, and 690 nm) at or below the energy of the bandgap plus the electron affinity, h ν≤Eg+Ea . These measurements were performed using a high voltage dc gun for varied photocathode surface fields of 1.4 -4.4 MV/m. Measurements of intrinsic emittance are performed using two different methods and were found to agree. At the longest wavelength available, 690 nm, the intrinsic emittance was 0.26 μm/mm-rms with a quantum efficiency of ˜10-4 . The suitability of NaKSb emitting at threshold for various low emittance applications is discussed.

  15. Wide-range Vacuum Measurements from MWNT Field Emitters Grown Directly on Stainless Steel Substrates

    Science.gov (United States)

    Zhang, Jian; Li, Detian; Zhao, Yangyang; Cheng, Yongjun; Dong, Changkun

    2016-01-01

    The field emission properties and the vacuum measurement application are investigated from the multi-walled carbon nanotubes (MWNTs) grown directly on catalytic stainless steel substrates. The MWNT emitters present excellent emission properties after the acid treatment of the substrate. The MWNT gauge is able to work down to the extreme-high vacuum (XHV) range with linear measurement performance in wide range from 10-11 to 10-6 Torr. A modulating grid is attempted with improved gauge sensitivity. The extension of the lower pressure limit is attributed largely to low outgassing effect due to direct growth of MWNTs and justified design of the electron source.

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

    CERN Document Server

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

    2018-01-01

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

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

    CERN Multimedia

    CERN. Geneva

    2014-01-01

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

  18. Studies of emittance growth in the ATF

    Energy Technology Data Exchange (ETDEWEB)

    Zimmermann, F.

    1997-03-01

    Several different mechanisms of emittance growth in the Accelerator Test Facility (ATF) at KEK are investigated: the author calculates rise times of the fast beam-ion instability for the damping ring (DR), and discusses the emittance growth caused by coherent synchrotron radiation in the beam-transport line (BT), the effect of quadrupole wake fields in the injector linac, and, finally, a single-bunch head-tail ion effect that can occur in both the DR and the BT. A first attempt to measure the quadrupole wake on the real machine is also reported.

  19. Studies of emittance growth in the ATF

    International Nuclear Information System (INIS)

    Zimmermann, F.

    1997-03-01

    Several different mechanisms of emittance growth in the Accelerator Test Facility (ATF) at KEK are investigated: the author calculates rise times of the fast beam-ion instability for the damping ring (DR), and discusses the emittance growth caused by coherent synchrotron radiation in the beam-transport line (BT), the effect of quadrupole wake fields in the injector linac, and, finally, a single-bunch head-tail ion effect that can occur in both the DR and the BT. A first attempt to measure the quadrupole wake on the real machine is also reported

  20. LHC MD2877: Beam-beam long range impact on coupling measurements

    CERN Document Server

    Wenninger, Jorg; Carlier, Felix Simon; Coello De Portugal - Martinez Vazquez, Jaime Maria; Fuchsberger, Kajetan; Hostettler, Michi; Persson, Tobias Hakan Bjorn; Tomas Garcia, Rogelio; Valuch, Daniel; Garcia-Tabares Valdivieso, Ana; CERN. Geneva. ATS Department

    2018-01-01

    The LHC is now operating with a tune separation of ∼0.004 in collision. This puts tight constraints on the allowed transverse coupling since a |C−| larger than a fraction of the fractional tune split may lead to beam instabilities. In the last years a new tool based on the ADT used in a similar way as an AC-dipole to excite the beam was developed. The ADT AC-dipole gives coherent oscillations without increasing the beam emittance. These oscillations are analyzed automatically to obtain the value of the coupling. A coupling measurement campaign was done in 2017 and while the correction converged and stayed rather constant over time it was observed that depending on the target bunch and filling scheme the results could vary by Δ|C−| ∼ 0.002. In this MD report we investigated 3 different bunches, one with Long Range Beam-Beam (LRBB) in IPs 1 and 5, one with LRBB in all IPs and one with no LRBB. The results indicate that there are differences in coupling between the bunches experiencing different LR...

  1. Beam tuning and stabilization using beam phase measurements at GANIL

    International Nuclear Information System (INIS)

    Chabert, A.; Loyer, F.; Sauret, J.

    1984-06-01

    Owing to the great sensitivity of the beam phase to the various parameters, on line beam phase measurements proved to be a very efficient way of tuning and stabilizing the beam of the multi-accelerator complex. We recall the system which allows to obtain the different kinds of accurate measurements we need and describe the main applications: - tuning process (buncher and SSC's RF phase determination, setting of the required radial beam phase law in the SSC's); - stabilization of the beam by loops, the basic principle of which being to keep constant the beam central phase all along the machine by adjusting RF voltages or magnetic fields. Feedback loops are described and comparative results with and without feedback are given

  2. H- beam neutralization measurements in a solenoidal beam transport system

    International Nuclear Information System (INIS)

    Sherman, J.; Pitcher, E.; Stevens, R.; Allison, P.

    1992-01-01

    H minus beam space-charge neutralization is measured for 65-mA, 35-keV beams extracted from a circular-aperture Penning surface-plasma source, the small-angle source. The H minus beam is transported to a RFQ matchpoint by a two-solenoid magnet system. Beam noise is typically ±4%. A four-grid analyzer is located in a magnetic-field-free region between the two solenoid magnets. H minus potentials are deduced from kinetic energy measurements of particles (electrons and positive ions) ejected radially from the beam channel by using a griddled energy analyzer. Background neutral gas density is increased by the introduction of additional Xe and Ar gases, enabling the H minus beam to become overneutralized

  3. IMPACT simulation and the SNS linac beam

    International Nuclear Information System (INIS)

    Zhang, Y.; Qiang, J.

    2008-01-01

    Multi-particle tracking simulations for the SNS linac beam dynamics studies are performed with the IMPACT code. Beam measurement results are compared with the computer simulations, including beam longitudinal halo and beam losses in the superconducting linac, transverse beam Courant-Snyder parameters and the longitudinal beam emittance in the linac. In most cases, the simulations show good agreement with the measured results

  4. Low-emittance Storage Rings

    CERN Document Server

    Wolski, Andrzej

    2014-01-01

    The effects of synchrotron radiation on particle motion in storage rings are discussed. In the absence of radiation, particle motion is symplectic, and the beam emittances are conserved. The inclusion of radiation effects in a classical approximation leads to emittance damping: expressions for the damping times are derived. Then, it is shown that quantum radiation effects lead to excitation of the beam emittances. General expressions for the equilibrium longitudinal and horizontal (natural) emittances are derived. The impact of lattice design on the natural emittance is discussed, with particular attention to the special cases of FODO-, achromat- and theoretical-minimum-emittance-style lattices. Finally, the effects of betatron coupling and vertical dispersion (generated by magnet alignment and lattice tuning errors) on the vertical emittance are considered.

  5. Direct-current proton-beam measurements at Los Alamos

    International Nuclear Information System (INIS)

    Sherman, J.; Stevens, R.R.; Schneider, J.D.; Zaugg, T.

    1994-01-01

    Recently, a CW proton accelerator complex was moved from Chalk River Laboratories (CRL) to Los Alamos National Laboratory. This includes a 50-keV dc proton injector with a single-solenoid low-energy beam transport system (LEBT) and a CW 1.25-MeV, 267-MHz radiofrequency quadrupole (RFQ). The move was completed after CRL had achieved 55-mA CW operation at 1.25 MeV using 250-kW klystrode tubes to power the RFQ. These accelerator components are prototypes for the front end of a CW linac required for an accelerator-driven transmutation linac, and they provide early confirmation of some CW accelerator components. The injector (ion source and LEBT) and emittance measuring unit are installed and operational at Los Alamos. The dc microwave ion source has been operated routinely at 50-keV, 75-mA hydrogen-ion current. This ion source has demonstrated very good discharge and H 2 gas efficiencies, and sufficient reliability to complete CW RFQ measurements at CRL. Proton fraction of 75% has been measured with 550-W discharge power. This high proton fraction removes the need for an analyzing magnet. Proton LEBT emittance measurements completed at Los Alamos suggest that improved transmission through the RFQ may be achieved by increasing the solenoid focusing current. Status of the final CW RFQ operation at CRL and the installation of the RFQ at Los Alamos is given

  6. Disruption effects on the beam size measurement

    International Nuclear Information System (INIS)

    Raimondi, P.; Decker, F.J.; Chen, P.

    1995-01-01

    At the SLC Final Focus with higher currents and smaller beam sizes, the disruption parameter D y is close to one and so the pinch effect should produce a luminosity enhancement. Since a flat beam-beam function is fit to deflection scan data to measure the beam size, disruption can affect the measurement. Here the authors discuss the quantitative effects of disruption for typical SLC beam parameters. With 3.5 10 10 particles per pulse, bunch length of 0.8 mm and beam sizes of 2.1 μm horizontally and 0.55 μm vertically, the measured vertical size can be as much as 25% bigger than the real one. Furthermore during the collision the spot size actually decrease, producing an enhancement factor H D of about 1.25. This would yield to a true luminosity which is 1.6 times that which is estimated from the beam-beam deflection fit

  7. Noninterceptive transverse beam diagnostics

    International Nuclear Information System (INIS)

    Chamberlin, D.D.; Minerbo, G.N.; Teel, L.E. Jr.; Gilpatrick, J.D.

    1981-01-01

    The transverse emittance properties of a high-current linear accelerator may be measured by using TV cameras sensitive to the visible radiation emitted following beam interactions with residual gas. This paper describes the TV system being used to measure emittances for the Fusion Materials Irradiation Test (FMIT) project

  8. Optics measurement and correction during beam acceleration in the Relativistic Heavy Ion Collider

    Energy Technology Data Exchange (ETDEWEB)

    Liu, C. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Marusic, A. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Minty, M. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.

    2014-09-09

    To minimize operational complexities, setup of collisions in high energy circular colliders typically involves acceleration with near constant β-functions followed by application of strong focusing quadrupoles at the interaction points (IPs) for the final beta-squeeze. At the Relativistic Heavy Ion Collider (RHIC) beam acceleration and optics squeeze are performed simultaneously. In the past, beam optics correction at RHIC has taken place at injection and at final energy with some interpolation of corrections into the acceleration cycle. Recent measurements of the beam optics during acceleration and squeeze have evidenced significant beta-beats which if corrected could minimize undesirable emittance dilutions and maximize the spin polarization of polarized proton beams by avoidance of higher-order multipole fields sampled by particles within the bunch. In this report the methodology now operational at RHIC for beam optics corrections during acceleration with simultaneous beta-squeeze will be presented together with measurements which conclusively demonstrate the superior beam control. As a valuable by-product, the corrections have minimized the beta-beat at the profile monitors so reducing the dominant error in and providing more precise measurements of the evolution of the beam emittances during acceleration.

  9. Emittance Growth of the LHC Beam due to the Effect of Head-on Beam-Beam Interaction and Ground Motion

    CERN Document Server

    Sen, T

    2000-01-01

    The influence of ground motion on the LHC beam is estimated by applying the existing theories of particle diffusion due to a weak-strong beam-beam collision with random offset at the interaction point. Noise at odd harmonics of the betatron frequency contributes significantly to particle diffusion. Extrapolating the characteristics of the random offset from the ground motion spectrum at the LHC site shows a fast fall-off with frequency and the amplitude is very small even at the first harmonic. We find that the head-on beam-beam force in the weak-strong approximation and ground motion by themselves do not induce significant diffusion over the lifetime of the beam.

  10. Emittance compensation in split photoinjectors

    Directory of Open Access Journals (Sweden)

    Klaus Floettmann

    2017-01-01

    Full Text Available The compensation of correlated emittance contributions is of primary importance to optimize the performance of high brightness photoinjectors. While only extended numerical simulations can capture the complex beam dynamics of space-charge-dominated beams in sufficient detail to optimize a specific injector layout, simplified models are required to gain a deeper understanding of the involved dynamics, to guide the optimization procedure, and to interpret experimental results. In this paper, a slice envelope model for the emittance compensation process in a split photoinjector is presented. The emittance term is included in the analytical solution of the beam envelope in a drift, which is essential to take the emittance contribution due to a beam size mismatch into account. The appearance of two emittance minima in the drift is explained, and the matching into the booster cavity is discussed. A comparison with simulation results points out effects which are not treated in the envelope model, such as overfocusing and field nonlinearities.

  11. Beam Profile Measurement in MTA Beam Line for High Pressure RF Cavity Beam Test

    International Nuclear Information System (INIS)

    Jana, M.R.; Bross, A.; Chung, M.; Greer, S.; Johnstone, C.; Kobilarcik, T.; Koizumi, G.; Leonova, M.; Moretti, A.; Popovic, M.; Schwartz, T.

    2012-01-01

    Recent High Pressure RF (HPRF) cavity experiment at MuCool Test Area (MTA) has used 400 MeV Linac proton beam to study the beam loading effect. When the energetic proton beam passes through the cavity, it ionizes the inside gas and produces the electrons. These electrons consume RF power inside the cavity. Number of electrons produced per cm inside the cavity (at 950 psi Hydrogen gas) per incident proton is ∼ 1200. The measurement of beam position and profile are necessary. MTA is flammable gas (Hydrogen) hazard zone so we have developed a passive beam diagnostic instrument using Chromox-6 scintillation screen and CCD camera. This paper presents quantitative information about beam position and beam profile. Neutral density filter was used to avoid saturation of CCD camera. Image data is filtered and fitted with Gaussian function to compute the beam size. The beam profile obtained from scintillation screen shall be compared with multi-wire beam profile.

  12. Ultra-low emittance beam generation using two-color ionization injection in a CO2 laser-driven plasma accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Schroeder, Carl [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Benedetti, Carlo [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Bulanov, Stepan [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Chen, Min [Shanghai Jiao Tong Univ. (China); Esarey, Eric [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Geddes, Cameron [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Vay, J. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Yu, Lule [Shanghai Jiao Tong Univ. (China); Leemans, Wim [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2015-05-21

    Ultra-low emittance (tens of nm) beams can be generated in a plasma accelerator using ionization injection of electrons into a wakefield. An all-optical method of beam generation uses two laser pulses of different colors. A long-wavelength drive laser pulse (with a large ponderomotive force and small peak electric field) is used to excite a large wakefield without fully ionizing a gas, and a short-wavelength injection laser pulse (with a small ponderomotive force and large peak electric field), co-propagating and delayed with respect to the pump laser, to ionize a fraction of the remaining bound electrons at a trapped wake phase, generating an electron beam that is accelerated in the wake. The trapping condition, the ionized electron distribution, and the trapped bunch dynamics are discussed. Expressions for the beam transverse emittance, parallel and orthogonal to the ionization laser polarization, are presented. An example is shown using a 10-micron CO2 laser to drive the wake and a frequency-doubled Ti:Al2O3 laser for ionization injection.

  13. Measurement of the most exotic beta-delayed neutron emitters at N=50 and N=126

    Science.gov (United States)

    Dillmann, Iris

    2017-09-01

    Beta-delayed neutron (βn)-emission will be the dominant decay mechanism of neutron-rich nuclei and plays an important role in the stellar nucleosynthesis of heavy elements in the ``r process''. It leads to a detour of the material β-decaying back to stability and the released neutrons increase the neutron-to-seed ratio, and are re-captured during the freeze-out phase and thus influence the final solar r-abundance curve. Thus the neutron branching ratio of very neutron-rich isotopes is a crucial parameter in astrophysical simulations. In addition, β-decay half-lives can be deduced from the time-dependent detection of βn's. I will talk about two recent experimental campaigns. The neutron detector BELEN was used at GSI Darmstadt to measure half-lives and neutron-branching ratios of the heaviest presently accessible βn-emitters at N=126. For isotopes between 204Au and 220Bi nine half-lives and eight neutron-branching ratios were measured for the first time and provide an important input for benchmarking theoretical models in this mass region. Its successor is the BRIKEN detector (``Beta-delayed neutron measurements at RIKEN for nuclear structure, astrophysics, and applications''), the most efficient neutron detector used so far for nuclear structure studies. In conjunction with two clover detectors and the ``Advanced Implantation Detector Array'' (AIDA) the setup has been used a few months ago to measure the most neutron-rich isotopes around 78Ni, 132Sn, and the Rare Earth Region. Some preliminary results are shown from the campaign covering the 78Ni region where the neutron-branching ratio of 78Ni and 28 more isotopes were measured for the first time, as well as the half-lives of 20 isotopes. The BRIKEN campaign aims to (re-)measure almost all βn-emitters between 76Co and 167Eu, many of them for the first time. An extension of the campaign to lighter masses is planned. This work has been supported by the NSERC and NRC in Canada, the US DOE, the Spanish

  14. Thermoreflectance microscopy measurements of the Joule heating characteristics of high- Tc superconducting terahertz emitters

    Science.gov (United States)

    Kashiwagi, Takanari; Tanaka, Taiga; Watanabe, Chiharu; Kubo, Hiroyuki; Komori, Yuki; Yuasa, Takumi; Tanabe, Yuki; Ota, Ryusei; Kuwano, Genki; Nakamura, Kento; Tsujimoto, Manabu; Minami, Hidetoshi; Yamamoto, Takashi; Klemm, Richard A.; Kadowaki, Kazuo

    2017-12-01

    Joule heating is the central issue in order to develop high-power and high-performance terahertz (THz) emission from mesa devices employing the intrinsic Josephson junctions in a layered high transition-temperature Tc superconductor. Here, we describe a convenient local thermal measurement technique using charge-coupled-device-based thermoreflectance microscopy, with the highest spatial resolution to date. This technique clearly proves that the relative temperature changes of the mesa devices between different bias points on the current-voltage characteristics can be measured very sensitively. In addition, the heating characteristics on the surface of the mesa devices can be detected more directly without any special treatment of the mesa surface such as previous coatings with SiC micro-powders. The results shown here clearly indicate that the contact resistance strongly affects the formation of an inhomogeneous temperature distribution on the mesa structures. Since the temperature and sample dependencies of the Joule heating characteristics can be measured quickly, this simple thermal evaluation technique is a useful tool to check the quality of the electrical contacts, electrical wiring, and sample defects. Thus, this technique could help to reduce the heating problems and to improve the performance of superconducting THz emitter devices.

  15. Measuring the Stellar Populations of Individual Lyman Alpha Emitters During the Epoch of Peak Star Formation

    Science.gov (United States)

    Reddy, Naveen

    2010-09-01

    Selecting galaxies by their strong Lyman-alpha emission provides a powerful means of probing the reionization epoch and the faint/low-mass galaxies that dominate star formation at high redshift. Yet, our understanding of high-redshift Lyman-alpha emitters {LAEs} has lagged behind that of other well-studied populations {e.g., Lyman break galaxies} due to their continuum faintness and the shifting of age/mass-sensitive features into the near-IR where the high terrestrial background inhibits deep observations. All existing studies of LAEs at z>2 have used stacked optical and/or Spitzer infrared data to discern their median properties, but the actual distributions of ages, reddenings, and stellar masses for these populations are poorly characterized. To fill this glaring gap in the observations and advance our understanding of this important population, we propose WFC3/IR+F160W imaging of fields where we have conducted a survey of low redshift {z 1.9} Lyman-alpha emitters {LAEs}, in order to measure their ages and stellar masses at an epoch where such observations directly probe the age-sensitive Balmer/4000 AA breaks. The targeted sample will include 45-50 spectroscopically confirmed LAEs at z=1.7-2.1 and roughly twice as many candidates, making it the largest sample of homogeneously selected LAEs with individual measurements of the ages, masses, and dust extinction. With these data we will {1} carefully take into account the age-dependence of the extinction curve to make robust comparisons between LAEs and continuum-selected galaxies at the same redshifts; {2} combine clustering and stellar mass measurements to infer the duty cycles of LAEs and determine if they are triggered in the presence of large-scale structures; and {3} quantify the importance of the LAE phase at different galaxy luminosity and mass scales, over a large dynamic range in these properties. An economical investment of just 12 orbits will allow us to accomplish these goals, and remains the only

  16. Microfabricated emitter array for an ionic liquid electrospray thruster

    Science.gov (United States)

    Nakagawa, Kaito; Tsuchiya, Toshiyuki; Takao, Yoshinori

    2017-06-01

    We have fabricated needle-shaped emitters on a Si wafer by a MEMS process, and measured the voltage-current characteristics and the frequency dependence of a bipolar pulse voltage for ionic liquid electrospray thrusters, which can be mounted on nanosatellites ( ≲ 10 kg). Although the extracted current did not increase with increasing number of emitters, probably owing to the lack of uniformity of the emitters fabricated, we have demonstrated that the emitted current depends on the gap distance between the emitter and the extractor grid electrode, and low frequencies of the bipolar pulse voltage are desirable for thruster operation. Moreover, the Bosch process is required for fabricating a reservoir of ionic liquid, which prevents undesirable electrical short circuits, and the minimum emitter pitch to prevent loss of ion beams to the extractor is estimated to be about 400 µm.

  17. Electron emitter pulsed-type cylindrical IEC

    International Nuclear Information System (INIS)

    Miley, G.H.; Gu, Y.; Stubbers, R.; Zich, R.; Anderl, R.; Hartwell, J.

    1997-01-01

    A cylindrical version of the single grid Inertial Electrostatic Confinement (IEC) device (termed the C-device) has been developed for use as a 2.5-MeV D-D fusion neutron source for neutron activation analysis. The C-device employs a hollow-tube type cathode with similar anodes backed up by ''reflector'' dishes. The resulting discharge differs from a conventional hollow cathode discharge, by creating an explicit ion beam which is ''pinched'' in the cathode region. Resulting fusion reactions generate ∼10 6 neutron/s. A pulsed version is under development for applications requiring higher fluxes. Several pulsing techniques are under study, including an electron emitter (e-emitter) assisted discharge in a thorated tungsten wire emitter located behind a slotted area in the reflector dishes. Pulsing is initiated after establishing a low power steady-state discharge by pulsing the e-emitter current using a capacitor switch type circuit. The resulting electron jet, coupled with the discharge by the biased slot array, creates a strong pulse in the pinched ion beam. The pulse length/repetition rate are controlled by the e-emitter pulse circuit. Typical parameters in present studies are ∼30micros, 10Hz and 1-amp ion current. Corresponding neutron measurements are an In-foil type activation counter for time averaged rates. Results for a wide variety of operating conditions are presented

  18. High-Precision Half-life Measurements for the Superallowed β+ Emitter 14O

    Directory of Open Access Journals (Sweden)

    Laffoley A. T.

    2014-03-01

    Full Text Available The half-life of 14O, a superallowed Fermi β+ emitter, has been determined via simultaneous γ and β counting experiments at TRIUMF’s Isotope Separator and Accelerator facility. Following the implantation of 14O samples at the center of the 8π spectrometer, a γ counting measurement was performed by detecting the 2313 keV γ-rays emitted from the first excited state of the daughter 14N using 20 high-purity germanium (HPGe detectors. A simultaneous β counting experiment was performed using a fast plastic scintillator positioned directly behind the implantation site. The results, T½(γ = 70:632 ± 0:094 s and T½(β = 70:610 ± 0:030 s, are consistent with one another and, together with eight previous measurements, establish a new average for the 14O half-life of T½ = 70:619 ± 0:011 s with a reduced χ2 of 0.99.

  19. First Beam Transfer Function measurements at LHC

    CERN Document Server

    Tambasco, Claudia; Fuchsberger, Kajetan; Lefevre, Thibaut; Pieloni, Tatiana; Barranco Garcia, Javier; Boccardi, Andrea; Gasior, Marek; Levens, Tom; Albert, Markus; CERN. Geneva. ATS Department

    2015-01-01

    For the first time in the LHC, Beam Transfer Function (BTF) measurements have been performed. Different machine configurations have been tested to determine the safety of the BTF measurement system that results to be completely transparent on single beam. To evaluate the spread given by different Landau octupole currents, an octupole current scan was performed. The data analysis is still ongoing. The BTF measurements have been tested also for beams in collision, the first attempt at 450 GeV resulted in the excitation of the beam-beam coherent -mode, while a second attempt at 6.5 GeV did not show any signs of instability. This is still under investigation and further tests are needed also with trains of bunches.

  20. In situ measurement of laser beam quality

    Science.gov (United States)

    Hashemi, Somayeh Sadat; Ghavami Sabouri, Saeed; Khorsandi, Alireza

    2017-09-01

    An innovative optical method is introduced for the beam quality measurement of any arbitrary transverse mode based on the reconstruction of the mode from a few-frame image of the beam cross-section. This is performed by the decomposition of a mode to its basic Hermite-Gaussian modal coefficients. The performance of the proposed method is examined through M 2-factor measurement of the beam of a Nd:YAG laser which was forced to oscillate in a certain mode using a crossed rectangular intracavity aperture. Obtained results have shown that this method can be alternatively replaced for the hologram- and ISO-based techniques recently exploiting for beam quality measurement regardless of the mode type and the position of utilized CCD camera along the beam direction.

  1. Phase measurement and control of bunched beams

    International Nuclear Information System (INIS)

    Lewis, R.N.

    1978-01-01

    An ion bean buncher was developed at ANL for bunching all ion species through a tandem accelerator. Transit time variations through the tandem, caused by ripple and fluctuations in the injection and lens power supplies and terminal voltage, and to varying voltage distributions in the accelerating tube, cause a beam-phase variation at the output of the tandem. A beam-phase measurement and control system was designed and installed in conjunction with the ion beam buncher to control beam phase at the tandem output. That system is described

  2. A device for measuring electron beam characteristics

    Directory of Open Access Journals (Sweden)

    M. Andreev

    2017-01-01

    Full Text Available This paper presents a device intended for diagnostics of electron beams and the results obtained with this device. The device comprises a rotating double probe operating in conjunction with an automated probe signal collection and processing system. This provides for measuring and estimating the electron beam characteristics such as radius, current density, power density, convergence angle, and brightness.

  3. Disruption effects on the beam size measurement

    Energy Technology Data Exchange (ETDEWEB)

    Raimondi, P.; Decker, F.J.; Chen, P.

    1995-06-01

    At the SLC Final Focus with higher currents and smaller beam sizes, the disruption parameter D{sub y} is close to one and so the pinch effect should produce a luminosity enhancement. Since a flat beam-beam function is fit to deflection scan data to measure the beam size, disruption can affect the measurement. Here the authors discuss the quantitative effects of disruption for typical SLC beam parameters. With 3.5 10{sup 10} particles per pulse, bunch length of 0.8 mm and beam sizes of 2.1 {mu}m horizontally and 0.55 {mu}m vertically, the measured vertical size can be as much as 25% bigger than the real one. Furthermore during the collision the spot size actually decrease, producing an enhancement factor H{sub D} of about 1.25. This would yield to a true luminosity which is 1.6 times that which is estimated from the beam-beam deflection fit.

  4. Overview of LHC Beam Loss Measurements

    CERN Document Server

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

    2011-01-01

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

  5. Experimental studies on coherent synchrotron radiaiton in the emittance exchange line at the Fermilab A0 Photoinjector

    International Nuclear Information System (INIS)

    Thangaraj, J.C.T.; Keup, R.; Johnson, A.; Ruan, J.; Piot, P.; Church, M.; Edwards, H.; Lumpkin, A.; Sun, Y.-E.; Santucci, J.

    2011-01-01

    Future accelerators will employ advanced beam conditioning systems such as emittance exchangers to manipulate high brightness beams. Coherent synchrotron radiation (CSR) in the dipoles could limit the performance of the emittance exchanger. In this paper, we report the experimental studies on measuring CSR and its effects on the beam at the A0 photoinjector in the emittance exchange line. After reporting the CSR power measurements, we report on the diagnostic scheme based on a weak skew quad in the emittance exchange line to study the CSR effects on the beam and other beam dynamics. In this work, we have reported on CSR measurements and the effect of skew quad on the dogleg line with the 5-cell turned on and off. We plan to study CSR effects on the bunch with the 5-cell on at larger chirp. This is will not only increase the CSR self-effect but also reduce the beamsize at the screen for convenient beamsize measurements.

  6. E-line: A new crystal collimator beam line for source size measurements at CHESS

    International Nuclear Information System (INIS)

    White, Jeffrey A.; Revesz, Peter; Finkelstein, Ken

    2007-01-01

    A new X-ray beam line has been constructed at cornell high energy synchrotron source (CHESS) to measure the vertical and horizontal source size of the positron particle beam. The cornell laboratory of elementary particle physics (LEPP) operates the storage ring (CESR) for X-ray generation for the CHESS user community by circulating electrons and their antimatter counterpart positrons in counter-rotating beams. As the laboratory reduces the emittances of particle beams to increase X-ray brilliance, there has been an increasing need for diagnostic tools to measure and monitor source size. A beam line front end that accesses the positron synchrotron light has been fitted with an experimental chamber and apparatus of compact design capable of horizontal and vertical source size measurement using the 'crystal collimator' technique, and an additional setup for vertical beam position monitoring using a luminescence-based X-ray video beam position monitoring system. The crystal collimators each consist of two Si(2 2 0) crystals in a dispersive (+,+) arrangement that diffract X-rays to a fluorescent material coated on a view port observed with a CCD camera. Measurements of the positron vertical beam size using the crystal collimation method at E-line are compared with measurements of visible synchrotron light at a remotely located dedicated port on the storage ring

  7. Systematic Errors of the Efficiency Tracer Technique for Measuring the Absolute Disintegration Rates of Pure Beta Emitters

    International Nuclear Information System (INIS)

    Williams, A.; Goodier, I.W.

    1967-01-01

    A basic requirement of, the theory of the efficiency tracer technique is the generally accepted assumption that there is a linear relationship between the efficiencies of the pure β-emitter and the tracer. However, an estimate of the inherent accuracy of the efficiency tracer technique has shown that, on theoretical grounds, this linear relationship would only be expected if the end-point energies and the shape of the β-spectra of the tracer and pure β-emitter were identical, the departure from linearity depending upon the ratio of the respective end-point energies. An experimentally determined value of the absolute disintegration rate of the pure emitter, obtained using a linear relationship, would have a significant systematic error if this relationship were in fact non-linear, for the usual straight-line extrapolation to 100% efficiency for the tracer would have to be replaced by an extrapolation with a significant curvature. To look for any non-linearity in the relationship it is first necessary to reduce the random measurement errors to a minimum. The first part of the paper contains a derivation of an expression for the expected value of these random errors in terms of the known statistical errors in the measurement. This expression shows that the ratio of the pure β-emitter and tracer activities can be chosen to make the random errors a minimum. The second part of the paper shows that it is possible to obtain an experimental error, which is comparable to that predicted in the expression derived above, for a pure β-emitter and tracer, combined in the same chemical form, whose end-point energies are similar (e.g. 32 P and 24 Na). To look for any non-linearity in the relationship between pure β-emitter and tracer efficiencies, 35 S (end-point energy E 0 = 168 keV) was measured with 60 Co(E 0 = 310 keV) and 134 Cs (effective E 0 = 110 keV) as tracers. The results of these measurements showed that there was a significant curvature, of opposite sign, for the

  8. Synchronization of streak and framing camera measurements of an intense relativistic electron beam propagating through gas

    International Nuclear Information System (INIS)

    Weidman, D.J.; Murphy, D.P.; Myers, M.C.; Meger, R.A.

    1994-01-01

    The expansion of the radius of a 5 MeV, 20 kA, 40 ns electron beam from SuperIBEX during propagation through gas is being measured. The beam is generated, conditions, equilibrated, and then passed through a thin foil that produces Cherenkov light, which is recorded by a streak camera. At a second location, the beam hits another Cherenkov emitter, which is viewed by a framing camera. Measurements at these two locations can provide a time-resolved measure of the beam expansion. The two measurements, however, must be synchronized with each other, because the beam radius is not constant throughout the pulse due to variations in beam current and energy. To correlate the timing of the two diagnostics, several shots have been taken with both diagnostics viewing Cherenkov light from the same foil. Experimental measurements of the Cherenkov light from one foil viewed by both diagnostics will be presented to demonstrate the feasibility of correlating the diagnostics with each other. Streak camera data showing the optical fiducial, as well as the final correlation of the two diagnostics, will also be presented. Preliminary beam radius measurements from Cherenkov light measured at two locations will be shown

  9. Test Beam Measurements on Picosec Gaseous Detector.

    CERN Document Server

    Sohl, Lukas

    2017-01-01

    In the Picosec project micro pattern gaseous detectors with a time resolution of some ten picoseconds are developed. The detectors are based on Micromegas detectors. With a cherenkov window and a photocathode the time jitter from different position of the primary ionization clusters can be substituted. This reports describes the beam setup and measurements of different Picosec prototypes. A time resolution of under 30 ps has been measured during the test beam. This report gives an overview of my work as a Summer Student. I set up and operated a triple-GEM tracker and a trigger system for the beam. During the beam I measured different prototypes of Picosec detectors and analysed the data.

  10. Beam divergence scaling in neutral beam injectors

    International Nuclear Information System (INIS)

    Holmes, A.J.T.

    1976-01-01

    One of the main considerations in the design of neutral beam injectors is to monimize the divergence of the primary ion beam and hence maximize the beam transport and minimize the input of thermal gas. Experimental measurements of the divergence of a cylindrical ion beam are presented and these measurements are used to analyze the major components of ion beam divergence, namely: space charge expansion, gas-ion scattering, emittance and optical aberrations. The implication of these divergence components in the design of a neutral beam injector system is discussed and a method of maximizing the beam current is described for a given area of source plasma

  11. 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

  12. Tomographic measurement of the phase space distribution of a space-charge-dominated beam

    Science.gov (United States)

    Stratakis, Diktys

    Many applications of accelerators, such as free electron lasers, pulsed neutron sources, and heavy ion fusion, require a good quality beam with high intensity. In practice, the achievable intensity is often limited by the dynamics at the low-energy, space-charge dominated end of the machine. Because low-energy beams can have complex distribution functions, a good understanding of their detailed evolution is needed. To address this issue, we have developed a simple and accurate tomographic method to map the beam phase using quadrupole magnets, which includes the effects from space charge. We extend this technique to use also solenoidal magnets which are commonly used at low energies, especially in photoinjectors, thus making the diagnostic applicable to most machines. We simulate our technique using a particle in cell code (PIC), to ascertain accuracy of the reconstruction. Using this diagnostic we report a number of experiments to study and optimize injection, transport and acceleration of intense space charge dominated beams. We examine phase mixing, by studying the phase-space evolution of an intense beam with a transversely nonuniform initial density distribution. Experimental measurements, theoretical predictions and PIC simulations are in good agreement each other. Finally, we generate a parabolic beam pulse to model those beams from photoinjectors, and combine tomography with fast imaging techniques to investigate the time-sliced parameters of beam current, size, energy spread and transverse emittance. We found significant differences between the slice emittance profiles and slice orientation as the beam propagates downstream. The combined effect of longitudinal nonuniform profiles and fast imaging of the transverse phase space provided us with information about correlations between longitudinal and transverse dynamics that we report within this dissertation.

  13. Very small beam-size measurement by a reflective synchrotron radiation interferometer

    Directory of Open Access Journals (Sweden)

    T. Naito

    2006-12-01

    Full Text Available A synchrotron radiation (SR interferometer with Herschelian reflective optics has been developed for the measurement of beams of several μm in size. In a conventional refractive SR interferometer, the dispersion effect of the objective lens limits the instrument to a smaller range of beam-size measurements. To avoid this problem, we designed a Herschelian arrangement of reflective optics for the interferometer. The effectiveness of the reflective SR interferometer was confirmed at the KEK Accelerator Test Facility (ATF damping ring. The measured vertical beam size obtained using the reflective SR interferometer was 4.7   μm and the estimated vertical emittance was 0.97×10^{-11}   m.

  14. DIAMOND SECONDARY EMITTER

    Energy Technology Data Exchange (ETDEWEB)

    BEN-ZVI, I.; RAO, T.; BURRILL, A.; CHANG, X.; GRIMES, J.; RANK, J.; SEGALOV, Z.; SMEDLEY, J.

    2005-10-09

    We present the design and experimental progress on the diamond secondary emitter as an electron source for high average power injectors. The design criteria for average currents up to 1 A and charge up to 20 nC are established. Secondary Electron Yield (SEY) exceeding 200 in transmission mode and 50 in emission mode have been measured. Preliminary results on the design and fabrication of the self contained capsule with primary electron source and secondary electron emitter will also be presented.

  15. Rare Earth Garnet Selective Emitter

    Science.gov (United States)

    Lowe, Roland A.; Chubb, Donald L.; Farmer, Serene C.; Good, Brian S.

    1994-01-01

    Thin film Ho-YAG and Er-YAG emitters with a platinum substrate exhibit high spectral emittance in the emission band (epsilon(sub lambda) approx. = 0.75, sup 4)|(sub 15/2) - (sup 4)|(sub 13/2),for Er-YAG and epsilon(sub lambda) approx. = 0.65, (sup 5)|(sub 7) - (sup 5)|(sub 8) for Ho-YAG) at 1500 K. In addition, low out-of-band spectral emittance, epsilon(sub lambda) less than 0.2, suggest these materials would be excellent candidates for high efficiency selective emitters in thermophotovoltaic (TPV) systems operating at moderate temperatures (1200-1500 K). Spectral emittance measurements of the thin films were made (1.2 less than lambda less than 3.0 microns) and compared to the theoretical emittances calculated using measured values of the spectral extinction coefficient. In this paper we present the results for a new class of rare earth ion selective emitters. These emitters are thin sections (less than 1 mm) of yttrium aluminum garnet (YAG) single crystal with a rare earth substitutional impurity. Selective emitters in the near IR are of special interest for thermophotovoltaic (TPV) energy conversion. The most promising solid selective emitters for use in a TPV system are rare earth oxides. Early spectral emittance work on rare earth oxides showed strong emission bands in the infrared (0.9 - 3 microns). However, the emittance outside the emission band was also significant and the efficiency of these emitters was low. Recent improvements in efficiency have been made with emitters fabricated from fine (5 - 10 microns) rare earth oxide fibers similar to the Welsbach mantle used in gas lanterns. However, the rare earth garnet emitters are more rugged than the mantle type emitters. A thin film selective emitter on a low emissivity substrate such as gold, platinum etc., is rugged and easily adapted to a wide variety of thermal sources. The garnet structure and its many subgroups have been successfully used as hosts for rare earth ions, introduced as substitutional

  16. Initial Measurements of CSR from a Bunch-Compressed Beam at APS

    CERN Document Server

    Lumpkin, Alex H; Borland, M; Sereno, N S

    2005-01-01

    The interest in bunch compression to generate higher peak current electron beams with low emittance continues in the free-electron laser (FEL) community. At the Advanced Photon source (APS) we have both an rf thermionic gun and an rf photocathode (PC) gun on the S-band linac. At the 150-MeV point in the linac, we have a flexible chicane bunch compressor whose four dipoles bend the beam in the horizontal plane. There is also a vertical bend dipole after the chicane that allows measurement of energy and horizontal beam size at the imaging screen station to study possible effects on emittance due to coherent synchrotron radiation (CSR) in the chicane. A far-infrared (FIR) coherent radiation monitor is located downstream of the chicane as well. We have begun recommissioning of this device with coherent transition radiation (CTR), but we also have directly observed CSR from the bunch-compressed beam as it transits the vertical dipole and goes into the down leg. The unique geometry allows simultaneous tracking of b...

  17. Measurements of Compression and Emittance Growth after the First LCLS Bunch Compressor Chicane

    International Nuclear Information System (INIS)

    Emma, P.

    2007-01-01

    The Linac Coherent Light Source (LCLS) is a SASE xray free-electron laser project presently under construction at SLAC. The injector section from RF photocathode gun through first bunch compressor chicane was installed during the fall of 2006. The first bunch compressor is located at 250 MeV and nominally compresses a 1-nC electron bunch from an rms length of about 1 mm to 0.2 mm. Transverse phase space and bunch length diagnostics are located immediately after the chicane. We present preliminary measurements and simulations of the longitudinal and transverse phase space after the chicane in various beam conditions, including extreme compression with micron-scale current spikes

  18. Beam measurements of the SPS longitudinal impedance

    CERN Document Server

    Lasheen, A

    2017-01-01

    Longitudinal instabilities are one of the main limitationsin the CERN SPS to reach the beam parameters requiredfor the High Luminosity LHC project. In preparation tothe SPS upgrade, possible remedies are studied by perform-ing macroparticle simulations using the machine impedancemodel obtained from electromagnetic simulations and mea-surements. To benchmark the impedance model, the resultsof simulations are compared with various beam measure-ments. In this study, the reactive part of the impedance wasprobed by measuring the quadrupole frequency shift withintensity, obtained from bunch length oscillations at mis-matched injection into the SPS. This method was appliedover many last years to follow up the evolution of the SPSimpedance, injecting bunches with the same bunch length.A novel approach, giving significantly more information,consists in varying the injected bunch length. The compari-son of these measurements with macroparticle simulationsallowed to test the existing model and identify some missingSPS i...

  19. Techniques for beam impedance measurements above cutoff

    International Nuclear Information System (INIS)

    Lambertson, G.R.; Jacob, A.F.; Rimmer, R.A.; Voelker, F.

    1990-08-01

    Methods for measuring beam impedance above cutoff have been very limited. For design work on the ALS we have developed two techniques that yield data in the frequency domain with high sensitivity. The first is an extension of the wire method; the second utilizes traveling TM waves to simulate the beam's fields at the wall, and thus avoids the mechanical difficulties of mounting the wire. It is also more sensitive than the other method but the interpretation is complicated by the presence of higher order modes. With either method we were able to detect resonant peaks smaller than 1 Ohm at 10 GHz

  20. Transverse beam shape measurements of intense proton beams using optical transition radiation

    Energy Technology Data Exchange (ETDEWEB)

    Scarpine, Victor E.; /Fermilab

    2012-03-01

    A number of particle physics experiments are being proposed as part of the Department of Energy HEP Intensity Frontier. Many of these experiments will utilize megawatt level proton beams onto targets to form secondary beams of muons, kaons and neutrinos. These experiments require transverse size measurements of the incident proton beam onto target for each beam spill. Because of the high power levels, most beam intercepting profiling techniques will not work at full beam intensity. The possibility of utilizing optical transition radiation (OTR) for high intensity proton beam profiling is discussed. In addition, previous measurements of OTR beam profiles from the NuMI beamline are presented.

  1. Aberrations and Emittance Growth in the DARHT 2nd Axis Downstream Transport

    Energy Technology Data Exchange (ETDEWEB)

    Schulze, Martin E. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-10-24

    The emittance of the DARHT 2nd Axis has been inferred from solenoid scans performed in the downstream transport (DST) region using a short kicked pulse. The beam spot size is measured by viewing optical transition radiation (OTR) in the near field as a function of the field (current) of a solenoid magnet (S4). The imaging station containing the OTR target is located about 100 cm downstream of the solenoid magnet. The emittance is then inferred using a beam optics code such as LAMDA or XTR by fitting the data to initial conditions upstream of the S4 solenoid magnet. The initial conditions are the beam size, beam convergence and emittance. The beam energy and current are measured. In preparation for a solenoid scan, the magnets upstream of the solenoid are adjusted to produce a round beam with no beam losses due to scraping in the beam tube. This is different from the standard tune in which the beam tune is adjusted to suppress the effects of ions and rf in the septum dump. In this standard tune, approximately 10% of the beam is lost due to scraping as the beam enters the small 3.75” ID beam tube after the septum. The normalized emittance inferred from recent solenoid scans typically ranges from 600 to 800 π(mm-mrad). This larger beam size increases the sensitivity to any non-linear fields in the Collins quadrupoles that are mounted along the small diameter beam tube. The primary magnet used to adjust the beam size in this region is the S3 solenoid magnet. Measurements made of the beam shape as the beam size was decreased showed significant structure consistent with non-linear fields. Using the measured magnetic fields in the Collins quadrupoles including higher order multipoles, the beam transport through the Collins quadrupoles is simulated and compared to the observed OTR images. The simulations are performed using the beam optics codes TRANSPORT [1] and TURTLE [2]. Estimates of the emittance growth and beam losses are made as a function of the S3

  2. ''Blood flow measurements in the irradiated pig skin using β emitters radionuclides''

    International Nuclear Information System (INIS)

    Daburon, F.; Lefaix, J.L.; Leplat, J.J.; Fayart, G.; Delacroix, D.; Le Thanh, P.

    1997-01-01

    Non invasive methods of study of the skin blood flow are numerous, but generally do not give any indication on the cutaneous micro-circulatory flow, except for cutaneous laser Doppler. The isotopic exploration of the skin with injected γ radionuclides, even of weak energy, doe snot allow to characterize the skin blood flow, because of the important contribution of the subcutaneous tissues. The use of β emitters energy spectrum, analyzed by different quantitative methods, are proportional to the thickness of the screen localized between the radioactive source and detector. Using simple and complex phantoms composed of tissue equivalent screens, with 32 P sources placed at different depths, it was possible to study the degradation of β spectra, simulating respectively the sub-epidermis and sub-dermis vascular levels. A modelization and an experimental study in-vivo are proposed in this work, with 32 P phosphate administered intravenously in pigs. (author)

  3. Beam lifetime measurement and analysis in Indus-2 electron ...

    Indian Academy of Sciences (India)

    In this paper, the beam lifetime measurement and its theoretical analysis are presented using measured vacuum pressure and applied radio frequency (RF) cavity voltage in Indus-2 electron storage ring at 2 GeV beam energy. Experimental studies of the effect of RF cavity voltage and bunched beam filling pattern on beam ...

  4. Turbulence measurements using six lidar beams

    DEFF Research Database (Denmark)

    Sathe, Ameya; Mann, Jakob

    2012-01-01

    components of the Reynolds stress tensor, which arises because, in a VAD scan the lidar beams are combined to obtain different components of the wind field. In this work we demonstrate theoretically, how the contamination by the cross components can be avoided by using the measured variances of the line......The use of wind lidars for measuring wind has increased significantly for wind energy purposes. The mean wind speed measurement using the velocity azimuth display (VAD) technique can now be carried out as reliably as the traditional instruments like the cup and sonic anemometers. Using the VAD...

  5. Measurement with hadron beams at COMPASS

    CERN Document Server

    Ferrero, Andrea

    2005-01-01

    The physics program of the COMPASS experiment at CERN focuses on the investigation of the hadron structure and spectroscopy, using both leptonic and hadronic probes. The COMPASS experiment has collected so far mostly data with polarized muon beams of 160 GeV, but also a pilot data taking with negative hadron beams of 190 GeV has been successfully completed at the end of the 2004 run. The main physics objectives of this pilot run are the study of soft pion-nuclei interactions. The predictions of the Chiral Perturbation Theory for the electric and magnetic polarizabilities of the pion will be verified through the study of the Primakoff scattering of 190 GeV pions on thin lead targets. A sample corresponding to an integrated beam flux of more than 10$^{11}$ pions has been collected for this purpose, and an equivalent sample with the muon beam of 190 GeV has been collected in the same experimental conditions to correct possible systematic effects. In parallel to the polarizability measurements, first data have al...

  6. Measurements of beam halo diffusion and population density in the Tevatron and in the Large Hadron Collider

    CERN Document Server

    Stancari, Giulio

    Halo dynamics influences global accelerator performance: beam lifetimes, emittance growth, dynamic aperture, and collimation efficiency. Halo monitoring and control are also critical for the operation of high-power machines. For instance, in the high-luminosity upgrade of the LHC, the energy stored in the beam tails may reach several megajoules. Fast losses can result in superconducting magnet quenches, magnet damage, or even collimator deformation. The need arises to measure the beam halo and to remove it at controllable rates. In the Tevatron and in the LHC, halo population densities and diffusivities were measured with collimator scans by observing the time evolution of losses following small inward or outward collimator steps, under different experimental conditions: with single beams and in collision, and, in the case of the Tevatron, with a hollow electron lens acting on a subset of bunches. After the LHC resumes operations, it is planned to compare measured diffusivities with the known strength of tran...

  7. 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.

  8. Online measurement of electron beam parameters by image processing

    International Nuclear Information System (INIS)

    Tyagi, Y.; Puntambekar, T.A.

    2010-01-01

    The basic image acquisition software which was developed earlier has been recently upgraded to support online measurement of beam centroid, beam height and beam width from the diagnostic devices namely fluorescent screen beam profile monitors and beam slit monitor installed in Transport Line -1(TL-1) at Indus Accelerator Complex at RRCAT, Indore. The online measurement of these electron beam parameters has helped the Indus operation team to take necessary corrective action if required before injection of the electron beam into booster synchrotron. This paper presents the methodology adopted for online measurement of above parameters in the software. (author)

  9. Cherenkov detector for beam quality measurement

    Science.gov (United States)

    Orfanelli, S.; CMS Collaboration

    2016-07-01

    A new detector to measure the machine induced background at larger radii has been developed and installed in the CMS experiment at the LHC. It consists of forty modules, each comprising a quartz bar read out by a photomultiplier tube. Since Cherenkov radiation is emitted in a forward cone around the charged particle trajectory, these detectors can distinguish between the arrival directions of the machine induced background and the collision products. The back-end electronics consists of a uTCA readout with excellent time resolution. The installation in the CMS is described and first commissioning measurements with the LHC beams in Run II are presented.

  10. Development of time-resolved optical measurement and diagnostic system for parameters of high current and pulsed electron beam

    International Nuclear Information System (INIS)

    Jiang Xiaoguo; Wang Yuan; Yang Guojun; Xia Liansheng; Li Hong; Zhang Zhuo; Liao Shuqing; Shi Jinshui

    2013-01-01

    The beam parameters measurement is the most important work for the study of linear induction accelerator(LIA). The beam parameters are important to evaluate the character of the beam. The demands of beam parameters measurement are improving while the development of accelerator is improving. The measurement difficulty feature higher time-resolved ability, higher spatial resolution, larger dynamic range and higher intuitionistic view data. The measurement technology of beam spot, beam emittance, beam energy have been developed for the past several years. Some high performance equipment such as high speed framing camera are developed recently. Under this condition, the relative integrated optical measurement and diagnostic system for the beam parameters is developed based on several principles. The system features time-resolved ability of up to 2 ns, high sensitivity and large dynamic range. The processing program is compiled for the data process and the local real-time process is reached. The measurement and diagnostic system has provided full and accurate data for the debug work and has been put into applications. (authors)

  11. Specialized beam diagnostic measurements for an ADTT accelerator funnel

    International Nuclear Information System (INIS)

    Gilpatrick, John Douglas

    1995-01-01

    Los Alamos National Laboratory has proposed several CW-proton-beam facilities for accelerator-driven transmutation technologies (ADTT) with beam-current densities greater than 5 mA/mm 2 . The primary beam-diagnostics-instrumentation requirement for these facilities is to provide sufficient beam information to understand and minimize beam-loss. To accomplish this task, the beam diagnostics instrumentation must measure beam parameters such as the projected centroids and profiles, total integrated current, and particle loss. Because of the high specific energy loss in materials at beam energies less than 20 MeV, interceptive measurements such as wire scanners or fluors cannot be used to determine beam profiles or centroids. Therefore, noninterceptive techniques must be used for on-line diagnosis of high-intensity CW beam at low energies. The beam funnel area of these proposed accelerator facilities provide a particular interesting beam measurement challenge. In this area of the accelerator, beam measurements must also sense how well the two funnel input-beams are matched to each other in phase space. This paper will discuss some of the measurement requirements for these proposed accelerator facilities and the various noninterceptive techniques to measure dual-beam funnel operation

  12. Specialized beam diagnostic measurements for an ADTT accelerator funnel

    International Nuclear Information System (INIS)

    Gilpatrick, J.D.

    1995-01-01

    Los Alamos National Laboratory has proposed several CW-proton-beam facilities for accelerator-driven transmutation technologies (ADTT) with beam-current densities greater than 5 mA/mm 2 . The primary beam-diagnostics-instrumentation requirement for these facilities is to provide sufficient beam information to understand and minimize beam-loss. To accomplish this task, the beam diagnostics instrumentation must measure beam parameters such as the projected centroids and profiles, total integrated current, and particle loss. Because of the high specific energy loss in materials at beam energies less than 20 MeV, interceptive measurements such as wire scanners or fluors cannot be used to determine beam profiles or centroids. Therefore, noninterceptive techniques must be used for on-line diagnosis of high-intensity CW beam at low energies. The beam funnel area of these proposed accelerator facilities provide a particular interesting beam measurement challenge. In this area of the accelerator, beam measurements must also sense how well the two funnel-input-beams are matched to each other in phase space. This paper will discuss some of the measurement requirements for these proposed accelerator facilities and the various noninterceptive techniques to measure dual-beam funnel operation

  13. Specialized beam diagnostic measurements for an ADTT accelerator funnel

    Energy Technology Data Exchange (ETDEWEB)

    Gilpatrick, J.D.

    1995-10-01

    Los Alamos National Laboratory has proposed several CW-proton-beam facilities for accelerator-driven transmutation technologies (ADTT) with beam-current densities greater than 5 mA/mm{sup 2}. The primary beam-diagnostics-instrumentation requirement for these facilities is to provide sufficient beam information to understand and minimize beam-loss. To accomplish this task, the beam diagnostics instrumentation must measure beam parameters such as the projected centroids and profiles, total integrated current, and particle loss. Because of the high specific energy loss in materials at beam energies less than 20 MeV, interceptive measurements such as wire scanners or fluors cannot be used to determine beam profiles or centroids. Therefore, noninterceptive techniques must be used for on-line diagnosis of high-intensity CW beam at low energies. The beam funnel area of these proposed accelerator facilities provide a particular interesting beam measurement challenge. In this area of the accelerator, beam measurements must also sense how well the two funnel-input-beams are matched to each other in phase space. This paper will discuss some of the measurement requirements for these proposed accelerator facilities and the various noninterceptive techniques to measure dual-beam funnel operation.

  14. 2-D emittance equation with acceleration and compression

    International Nuclear Information System (INIS)

    Hahn, K.D.; Smith, L.

    1988-10-01

    Since both acceleration and compression are required for an Inertial Fusion Driver, the understanding of their effect on the beam quality, emittance, is important. This report attempts to generalize the usual emittance formula for the drifting beam to include these effects. The derivation of the 2-D emittance equation is carried out and a comparison with the particle code results is given. The 2-D emittance at a given axial location is reasonable to consider for a long beam, particularly with velocity tilt; transverse emittance averaged over the entire bunch is not a useful quantity. 6 refs., 2 figs., 1 tab

  15. Realisation of a ultra-high vacuum system and technique development of microscopical emitters preparation in silicium. First measurements of field emission current and field photoemission

    International Nuclear Information System (INIS)

    El Manouni, A.

    1990-12-01

    The development of research in the domain of photocathode (electron sources) illuminated by laser light to produce intense multiple bunches of electrons in short time is needed by many applications as linear collider e + e - , free electron laser, lasertron, etc... In this way, after a study of field emission, of photoemission and of photofield emission, we prepared microscopical emitters in silicium heavy and weakly doped a boron using a technique of microlithography. Then, we realized a system of ultra-high vacuum of studying property of emission from photocathodes realized. The experiment results obtained in field emission and photofield emission have shown that a behaviour unexpected for P-silicium tips array compared to P + -silicon tips array. With P-type silicon, a quantum yield of 21 percent has been measured for laser power of 140 mW and for applied field of 1.125 x 10 7 V/m and an instantaneous response to laser light beam has been observed. It has been noted that presence of oxyde at the surface of photocathode limits extensively the emission current. The fluctuations of emission current are due to quality of vacuum [fr

  16. Measurements of the Argonne Wakefield Accelerator close-quote s low charge, 4 MeV RF photocathode witness beam

    International Nuclear Information System (INIS)

    Power, J.; Chojnacki, E.; Conde, M.; Gai, W.; Konecny, R.; Schoessow, P.; Simpson, J.

    1997-01-01

    The Argonne Wakefield Accelerator close-quote s (AWA) witness RF photocathode gun produced its first electron beam in April of 1996. We have characterized the charge, energy, emittance and bunch length of the witness beam over the last several months. The emittance was measured by both a quad scan that fitted for space charge using an in house developed Mathematica routine and a pepper pot technique. The bunch length was measured by imaging Cherenkov light from a quartz plate to a Hamamatsu streak camera with 2 psec resolution. A beam energy of 3.9 MeV was measured with a 6 inch round pole spectrometer while a beam charge was measured with both an ICT and a Faraday Cup. Although the gun will normally be run at 100 pC it has produced charges from 10 pC to 4 nC. All results of the measurements to date are presented here. copyright 1997 American Institute of Physics

  17. Microstructure cantilever beam for current measurement

    Directory of Open Access Journals (Sweden)

    M.T.E. Khan

    2010-01-01

    Full Text Available Most microelectromechanical systems (MEMS sensors are based on the microcantilever technology, which uses a broad range of design materials and structures. The benefit ofMEMStechnology is in developing devices with a lower cost, lower power consumption, higher performance and greater integration. A free-end cantilever beam with a magnetic material mass has been designed using MEMS software tools. The magnetic material was used to improve the sensitivity of the cantilever beam to an externally-applied magnetic field. The cantilever was designed to form a capacitance transducer, which consisted of variable capacitance where electrical and mechanical energies were exchanged. The aim of this paper was to analyse the system design of the microcantilever when subjected to a magnetic field produced by a current-carrying conductor. When the signal, a sinusoidal current with a constant frequency, was applied, the cantilever beam exhibited a vibration motion along the vertical axis when placed closer to the line current. This motion created corresponding capacitance changes and generated a voltage output proportional to the capacitive change in the signal-processing circuitry attached to the microcantilever. The equivalent massspring system theory was used to describe and analyse the effect of the natural frequency of the system vibrations and motion due to the applied magnetic field, in a single-degree of freedom. The main application of this microcantilever is in current measurements to develop a non-contact current sensor mote.

  18. Investigations on the transverse phase space at a photo injector for minimized emittance

    International Nuclear Information System (INIS)

    Miltchev, V.

    2006-08-01

    Radio frequency photoinjectors are electron sources able to generate beams of extremely high brightness, which are applicable to linac driven Free Electron Lasers (FEL). Because of the high phase space density, the dynamics of the electron beam is dominated by space charge interactions between the particles. This thesis studies the transverse phase space of space charge dominated electron beams produced by the Photo Injector Test Facility in Zeuthen (PITZ). The operation conditions for minimizing the transverse emittance are studied experimentally, theoretically and in simulations. The influence of the longitudinal profile of the driving UV laser pulse on the transverse emittance is investigated. Emphasis is placed on the experimental study of the emittance as a function of different machine parameters like the laser beam spot size, the amplitude of the focusing magnetic field, the rf phase and the electron bunch charge. First investigations on the thermal emittance for Cs 2 Te photocathodes under rf operating conditions are presented. Measurements of the thermal emittance scaling with the photocathode laser spot size are analyzed. The significance of the applied rf field in the emittance formation process is discussed. (orig.)

  19. Investigations on the transverse phase space at a photo injector for minimized emittance

    Energy Technology Data Exchange (ETDEWEB)

    Miltchev, V.

    2006-08-15

    Radio frequency photoinjectors are electron sources able to generate beams of extremely high brightness, which are applicable to linac driven Free Electron Lasers (FEL). Because of the high phase space density, the dynamics of the electron beam is dominated by space charge interactions between the particles. This thesis studies the transverse phase space of space charge dominated electron beams produced by the Photo Injector Test Facility in Zeuthen (PITZ). The operation conditions for minimizing the transverse emittance are studied experimentally, theoretically and in simulations. The influence of the longitudinal profile of the driving UV laser pulse on the transverse emittance is investigated. Emphasis is placed on the experimental study of the emittance as a function of different machine parameters like the laser beam spot size, the amplitude of the focusing magnetic field, the rf phase and the electron bunch charge. First investigations on the thermal emittance for Cs{sub 2}Te photocathodes under rf operating conditions are presented. Measurements of the thermal emittance scaling with the photocathode laser spot size are analyzed. The significance of the applied rf field in the emittance formation process is discussed. (orig.)

  20. Commissioning experience and beam physics measurements at the SwissFEL Injector Test Facility

    Directory of Open Access Journals (Sweden)

    T. Schietinger

    2016-10-01

    Full Text Available The SwissFEL Injector Test Facility operated at the Paul Scherrer Institute between 2010 and 2014, serving as a pilot plant and test bed for the development and realization of SwissFEL, the x-ray Free-Electron Laser facility under construction at the same institute. The test facility consisted of a laser-driven rf electron gun followed by an S-band booster linac, a magnetic bunch compression chicane and a diagnostic section including a transverse deflecting rf cavity. It delivered electron bunches of up to 200 pC charge and up to 250 MeV beam energy at a repetition rate of 10 Hz. The measurements performed at the test facility not only demonstrated the beam parameters required to drive the first stage of an FEL facility, but also led to significant advances in instrumentation technologies, beam characterization methods and the generation, transport and compression of ultralow-emittance beams. We give a comprehensive overview of the commissioning experience of the principal subsystems and the beam physics measurements performed during the operation of the test facility, including the results of the test of an in-vacuum undulator prototype generating radiation in the vacuum ultraviolet and optical range.

  1. 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.

  2. Faraday Cup - it is used to measure beam intensities at low energy beams.

    CERN Multimedia

    Maximilien Brice

    2005-01-01

    A Faraday Cup is used to measure beam intensities at low energy beams. An electrically isolated metallic electrode intercepts the beam and captures all its charges. These charges are integrated using an current sensitive amplifier. When the beam impinges onto the electrode surface low energy electrons are liberated. In order to prevent these electrons from escaping the cup and thus falsifying the measurement, a repeller electrode with negative potential pushes the electrons back onto the electrode.

  3. Accurate estimation of the RMS emittance from single current amplifier data

    International Nuclear Information System (INIS)

    Stockli, Martin P.; Welton, R.F.; Keller, R.; Letchford, A.P.; Thomae, R.W.; Thomason, J.W.G.

    2002-01-01

    This paper presents the SCUBEEx rms emittance analysis, a self-consistent, unbiased elliptical exclusion method, which combines traditional data-reduction methods with statistical methods to obtain accurate estimates for the rms emittance. Rather than considering individual data, the method tracks the average current density outside a well-selected, variable boundary to separate the measured beam halo from the background. The average outside current density is assumed to be part of a uniform background and not part of the particle beam. Therefore the average outside current is subtracted from the data before evaluating the rms emittance within the boundary. As the boundary area is increased, the average outside current and the inside rms emittance form plateaus when all data containing part of the particle beam are inside the boundary. These plateaus mark the smallest acceptable exclusion boundary and provide unbiased estimates for the average background and the rms emittance. Small, trendless variations within the plateaus allow for determining the uncertainties of the estimates caused by variations of the measured background outside the smallest acceptable exclusion boundary. The robustness of the method is established with complementary variations of the exclusion boundary. This paper presents a detailed comparison between traditional data reduction methods and SCUBEEx by analyzing two complementary sets of emittance data obtained with a Lawrence Berkeley National Laboratory and an ISIS H - ion source

  4. Commissioning experience and beam physics measurements at the SwissFEL Injector test Facility

    CERN Document Server

    Schietinger, T.; Aiba, M.; Arsov, V.; Bettoni, S.; Beutner, B.; Calvi, M.; Craievich, P.; Dehler, M.; Frei, F.; Ganter, R.; Hauri, C. P.; Ischebeck, R.; Ivanisenko, Y.; Janousch, M.; Kaiser, M.; Keil, B.; Löhl, F.; Orlandi, G. L.; Ozkan Loch, C.; Peier, P.; Prat, E.; Raguin, J.-Y.; Reiche, S.; Schilcher, T.; Wiegand, P.; Zimoch, E.; Anicic, D.; Armstrong, D.; Baldinger, M.; Baldinger, R.; Bertrand, A.; Bitterli, K.; Bopp, M.; Brands, H.; Braun, H. H.; Brönnimann, M.; Brunnenkant, I.; Chevtsov, P.; Chrin, J.; Citterio, A.; Csatari Divall, M.; Dach, M.; Dax, A.; Ditter, R.; Divall, E.; Falone, A.; Fitze, H.; Geiselhart, C.; Guetg, M. W.; Hämmerli, F.; Hauff, A.; Heiniger, M.; Higgs, C.; Hugentobler, W.; Hunziker, S.; Janser, G.; Kalantari, B.; Kalt, R.; Kim, Y.; Koprek, W.; Korhonen, T.; Krempaska, R.; Laznovsky, M.; Lehner, S.; Le Pimpec, F.; Lippuner, T.; Lutz, H.; Mair, S.; Marcellini, F.; Marinkovic, G.; Menzel, R.; Milas, N.; Pal, T.; Pollet, P.; Portmann, W.; Rezaeizadeh, A.; Ritt, S.; Rohrer, M.; Schär, M.; Schebacher, L.; Scherrer, St.; Schlott, V.; Schmidt, T.; Schulz, L.; Smit, B.; Stadler, M.; Steffen, Bernd; Stingelin, L.; Sturzenegger, W.; Treyer, D. M.; Trisorio, A.; Tron, W.; Vicario, C.; Zennaro, R.; Zimoch, D.

    2016-10-26

    The SwissFEL Injector Test Facility operated at the Paul Scherrer Institute between 2010 and 2014, serving as a pilot plant and test bed for the development and realization of SwissFEL, the x-ray Free Electron Laser facility under construction at the same institute. The test facility consisted of a laser-driven rf electron gun followed by an S-band booster linac, a magnetic bunch compression chicane and a diagnostic section including atransverse deflecting rf cavity. It delivered electron bunchesof up to200 pC chargeand up to 250 MeV beam energy at a repetition rate of 10 Hz. The measurements performed at the test facility not only demonstrated the beam parameters required to drive the first stage of a FEL facility, but also led to significant advances in instrumentation technologies, beam characterization methods and the generation, transport and compression of ultralow-emittance beams. We give a comprehensive overview of the commissioning experience of the principal subsystems and the beam physics measureme...

  5. On the preservation of single- and multi-bunch emittance in linear accelerators

    International Nuclear Information System (INIS)

    Drevlak, M.

    1995-11-01

    This document is concentrated on the investigation of the dynamics of a particle beam in a linear accelerator. We numerically simulate a number of effects and evaluate the severity of their impact on the beam. Furthermore, we examine the applicability of several correction techniques aiming at the suppression or correction of the effects diluting the beam emittance. First, there is the issue of single-bunch dynamics : we see that wake field effects and dispersive errors can cause a significant emittance growth. Secondly, long range dipole wakes and dispersive effects arising from the energy spread between different bunches will cause relative offsets between the individual bunches and likewise result in emittance growth. Finally, we observe interactions between the single-bunch and multi-bunch dynamics in a bunch train, which further aggravate these effects. The corrective measures against emittance growth are first tested with respect to individual effects relating to issues of single- or multi-bunch dynamics. Later, these different correction techniques are joined to one machine tuning procedure that will be applied in order to achieve good emittance preservation for operation of the accelerator with a full beam consisting of the full number of bunches. The performance of this procedure is tested in simulations of the combined single- and multi-bunch dynamics. Finally, tolerances on the machine alignment as well as machine and beam parameters are established. (orig.)

  6. Measuring the clustering of simulated surveys of high-redshift Lyman-Alpha Emitters with the Void Probability Function

    Science.gov (United States)

    Perez, Lucia A.; Tilvi, Vithal; Malhotra, Sangeeta; Rhoads, James E.

    2018-01-01

    The void probability function (VPF) has shown promise as a more sensitive and efficient probe of the large scale structure of the universe as compared to other methods. By measuring the probability that a given space will have no galaxies within it, this measure detects clustering more quickly and yielding different information than the traditional method of quantifying the average distance between a given number of galaxies, while still tying theoretically to these correlation functions. This work presents comparative measurements of the traditional two-point correlation function and the two and three dimensional VPF of multiple simulations of Lyman-Alpha emitter (LAE) inhabited dark matter halos across a wide redshift range, finding evidence for increased clustering of LAEs at higher redshifts. We also calculate the VPF of simulated mock LAE samples at different intergalactic medium mean ionized fractions, finding that the VPF is also able to detect the additional clustering caused by an increasingly neutral IGM. These results provide evidence for the VPF as an accurate and significantly less computationally intensive measure of clustering for large galaxy surveys.

  7. Emission measurement of diesel vehicles in Hong Kong through on-road remote sensing: Performance review and identification of high-emitters.

    Science.gov (United States)

    Huang, Yuhan; Organ, Bruce; Zhou, John L; Surawski, Nic C; Hong, Guang; Chan, Edward F C; Yam, Yat Shing

    2018-02-23

    A two-year remote sensing measurement program was carried out in Hong Kong to obtain a large dataset of on-road diesel vehicle emissions. Analysis was performed to evaluate the effect of vehicle manufacture year (1949-2015) and engine size (0.4-20 L) on the emission rates and high-emitters. The results showed that CO emission rates of larger engine size vehicles were higher than those of small vehicles during the study period, while HC and NO were higher before manufacture year 2006 and then became similar levels between manufacture years 2006 and 2015. CO, HC and NO of all vehicles showed an unexpectedly increasing trend during 1998-2004, in particular ≥6001 cc vehicles. However, they all decreased steadily in the last decade (2005-2015), except for NO of ≥6001 cc vehicles during 2013-2015. The distributions of CO and HC emission rates were highly skewed as the dirtiest 10% vehicles emitted much higher emissions than all the other vehicles. Moreover, this skewness became more significant for larger engine size or newer vehicles. The results indicated that remote sensing technology would be very effective to screen the CO and HC high-emitters and thus control the on-road vehicle emissions, but less effective for controlling NO emissions. No clear correlation was observed between the manufacture year and percentage of high-emitters for ≤3000 cc vehicles. However, the percentage of high-emitters decreased with newer manufacture year for larger vehicles. In addition, high-emitters of different pollutants were relatively independent, in particular NO emissions, indicating that high-emitter screening criteria should be defined on a CO-or-HC-or-NO basis, rather than a CO-and-HC-and-NO basis. Copyright © 2018 Elsevier Ltd. All rights reserved.

  8. Dependence of beam emittance on plasma electrode temperature and rf-power, and filter-field tuning with center-gapped rod-filter magnets in J-PARC rf-driven H− ion source

    International Nuclear Information System (INIS)

    Ueno, A.; Koizumi, I.; Ohkoshi, K.; Ikegami, K.; Takagi, A.; Yamazaki, S.; Oguri, H.

    2014-01-01

    The prototype rf-driven H − ion-source with a nickel plated oxygen-free-copper (OFC) plasma chamber, which satisfies the Japan Proton Accelerator Research Complex (J-PARC) 2nd stage requirements of a H − ion beam current of 60 mA within normalized emittances of 1.5 π mm mrad both horizontally and vertically, a flat top beam duty factor of 1.25% (500 μs × 25 Hz) and a life-time of more than 50 days, was reported at the 3rd international symposium on negative ions, beams, and sources (NIBS2012). The experimental results of the J-PARC ion source with a plasma chamber made of stainless-steel, instead of nickel plated OFC used in the prototype source, are presented in this paper. By comparing these two sources, the following two important results were acquired. One was that the about 20% lower emittance was produced by the rather low plasma electrode (PE) temperature (T PE ) of about 120 °C compared with the typically used T PE of about 200 °C to maximize the beam current for the plasma with the abundant cesium (Cs). The other was that by using the rod-filter magnets with a gap at each center and tuning the gap-lengths, the filter-field was optimized and the rf-power necessary to produce the J-PARC required H − ion beam current was reduced typically 18%. The lower rf-power also decreases the emittances

  9. Application of digital beam position processor Libera on tune measurement

    International Nuclear Information System (INIS)

    Zhang Chunhui; Sun Baogen; Cao Yong; Lu Ping; Li Jihao

    2006-01-01

    Digital signal processing (DSP) is widely used in the field of beam diagnostics. Especially, DSP achieves very good performance in beam position signal analysis and betatron tune measurement. In Hefei light source, when beam was excited by narrow-band Gaussian white nose, Libera, a digital beam position processor, was used to process the signals from beam position monitor (BPM), which contained betatron oscillation. Fast Fourier transform (FFT) was applied to finding out betatron resonance frequency, from which the decimal part of betatron oscillation tune was calculated. By this means, the measure of horizontal tune was 3.5352 and the measure of vertical tune is 2.6299. (authors)

  10. Muon Cooling - Emittance Exchange

    International Nuclear Information System (INIS)

    Parsa, Z.

    2001-01-01

    Muon Cooling is the key factor in building of a Muon collider, (to a less degree) Muon storage ring, and a Neutrino Factory. Muon colliders potential to provide a probe for fundamental particle physics is very interesting, but may take a considerable time to realize, as much more work and study is needed. Utilizing high intensity Muon sources - Neutrino Factories, and other intermediate steps are very important and will greatly expand our abilities and confidence in the credibility of high energy muon colliders. To obtain the needed collider luminosity, the phase-space volume must be greatly reduced within the muon life time. The Ionization cooling is the preferred method used to compress the phase space and reduce the emittance to obtain high luminosity muon beams. We note that, the ionization losses results not only in damping, but also heating. The use of alternating solenoid lattices has been proposed, where the emittance are large. We present an overview of the cooling and discuss formalism, solenoid magnets and some beam dynamics

  11. Alternative techniques for beam halo measurements

    CERN Document Server

    Welsch, CP; Burel, B; Lefèvre, T; Chapman, T; Pilon, MJ

    2006-01-01

    In future high intensity, high energy accelerators it must be ensured that particle losses are minimized, as activation of the vacuum chambers or other components makes maintenance and upgrade work time consuming and costly. It is imperative to have a clear understanding of the mechanisms that can lead to halo formation and to have the possibility to test available theoretical models with an adequate experimental setup. Measurements based on optical transition radiation (OTR) are a well-established technique for measurements of the transverse beam profile. However, in order to be suitable for halo measurements as well, the dynamic range of the final image acquisition system needs to be high, being able to cover at least five orders of magnitude in intensity changes. Here, the performance of a standard acquisition system as it is used in the CLIC test facility (CTF3) is compared to a step-by-step measurement with a small movable photo multiplier tube and an innovative camera system based on charge injection de...

  12. Measuring the electron beam energy in a magnetic bunch compressor

    International Nuclear Information System (INIS)

    Hacker, Kirsten

    2010-09-01

    Within this thesis, work was carried out in and around the first bunch compressor chicane of the FLASH (Free-electron LASer in Hamburg) linear accelerator in which two distinct systems were developed for the measurement of an electron beams' position with sub-5 μm precision over a 10 cm range. One of these two systems utilized RF techniques to measure the difference between the arrival-times of two broadband electrical pulses generated by the passage of the electron beam adjacent to a pickup antenna. The other system measured the arrival-times of the pulses from the pickup with an optical technique dependent on the delivery of laser pulses which are synchronized to the RF reference of the machine. The relative advantages and disadvantages of these two techniques are explored and compared to other available approaches to measure the same beam property, including a time-of-flight measurement with two beam arrival-time monitors and a synchrotron light monitor with two photomultiplier tubes. The electron beam position measurement is required as part of a measurement of the electron beam energy and could be used in an intra-bunch-train beam-based feedback system that would stabilize the amplitude of the accelerating field. By stabilizing the accelerating field amplitude, the arrival-time of the electron beam can be made more stable. By stabilizing the electron beam arrival-time relative to a stable reference, diagnostic, seeding, and beam-manipulation lasers can be synchronized to the beam. (orig.)

  13. Design, construction and measurements of an alpha magnet as a solution for compact bunch compressor for the electron beam from Thermionic RF Gun

    Science.gov (United States)

    Rajabi, A.; Jazini, J.; Fathi, M.; Sharifian, M.; Shokri, B.

    2018-03-01

    The beam produced by a thermionic RF gun has wide energy spread that makes it unsuitable for direct usage in photon sources. Here in the present work, we optimize the extracted beam from a thermionic RF gun by a compact economical bunch compressor. A compact magnetic bunch compressor (Alpha magnet) is designed and constructed. A comparison between simulation results and experimental measurements shows acceptable conformity. The beam dynamics simulation results show a reduction of the energy spread as well as a compression of length less than 1 ps with 2.3 mm-mrad emittance.

  14. Selective generation and extraction of low emittance electrons from plasmas: A new concept for E-beam cathodes

    International Nuclear Information System (INIS)

    Hershcovitch, A.

    1991-01-01

    It is shown that hollow cathode discharges can operate in a mode characterized by a two-component electron energy distribution: bulk electrons with a thermal distribution with a temperature of a few electron volts, and a component of fast electrons with an energy of about 30 eV and a thermal spread of about 0.1 eV. Measurements of both parallel and perpendicular energy spreads confirm the existence of fast, low energy spread electrons. Selective extraction of these electrons can form the basis of a high current, high brightness electron gun which could be well suited for EBIS applications. 8 refs., 4 figs., 1 tab

  15. Asymmetrical field emitter

    Science.gov (United States)

    Fleming, J.G.; Smith, B.K.

    1995-10-10

    A method is disclosed for providing a field emitter with an asymmetrical emitter structure having a very sharp tip in close proximity to its gate. One preferred embodiment of the present invention includes an asymmetrical emitter and a gate. The emitter having a tip and a side is coupled to a substrate. The gate is connected to a step in the substrate. The step has a top surface and a side wall that is substantially parallel to the side of the emitter. The tip of the emitter is in close proximity to the gate. The emitter is at an emitter potential, and the gate is at a gate potential such that with the two potentials at appropriate values, electrons are emitted from the emitter. In one embodiment, the gate is separated from the emitter by an oxide layer, and the emitter is etched anisotropically to form its tip and its asymmetrical structure. 17 figs.

  16. Multibunch Emittance Preservation in CLIC

    CERN Document Server

    Guignard, Gilbert

    1996-01-01

    In high-frequency linacs, where the wakefields are strong, the stability of a train of bunches is critical. The beam break-up due to long range wakefields induces a decoherence of the bunch oscillations and a consequent blow-up of the effective betatron emittances of the whole train. Since the Compact Linear Collider (CLIC) study now includes several bunches per pulse, it is important to analyse numerically and theoretically this emittance blow-up. possibilities of controlling the beam break-up without upsetting the single bunch stability have been considered: first a multibunch generalization of the BNS damping principle, secondly an attenuation of the long-range fields, and thirdly an increase of the focusing in order to overconstrain the beam. Simulation codes have been written for both checking the theoretical predictions and investigating the requirements associated with a possible application to the main linac. Animated graphics make it possible to get a didactic display of the multibunch instability.

  17. Exact cancellation of emittance growth due to coupled transverse dynamics in solenoids and rf couplers

    Science.gov (United States)

    Dowell, David H.; Zhou, Feng; Schmerge, John

    2018-01-01

    Weak, rotated magnetic and radio frequency quadrupole fields in electron guns and injectors can couple the beam's horizontal with vertical motion, introduce correlations between otherwise orthogonal transverse momenta, and reduce the beam brightness. This paper discusses two important sources of coupled transverse dynamics common to most electron injectors. The first is quadrupole focusing followed by beam rotation in a solenoid, and the second coupling comes from a skewed high-power rf coupler or cavity port which has a rotated rf quadrupole field. It is shown that a dc quadrupole field can correct for both types of couplings and exactly cancel their emittance growths. The degree of cancellation of the rf skew quadrupole emittance is limited by the electron bunch length. Analytic expressions are derived and compared with emittance simulations and measurements.

  18. Digital DC beam current measurement on SSRF storage ring

    International Nuclear Information System (INIS)

    Xiong Liang; Yin Chongxian; Liu Ming; Chen Jianfeng

    2011-01-01

    Both DC current transformer (DCCT) and integrating current transformer (ICT) can be used in DC beam current measurement. The ICT has strong capability of resisting electromagnetic interference, but its measurement accuracy cannot satisfy the DC beam current measurement requirement when using traditional high speed A/D. With high resolution A/D and equivalent sampling system, DC beam current measuring system based on ICT can reach high accuracy compared with DCCT system. In this paper, the ICT-based DC beam current measurement, equivalent sampling method and testing results at Shanghai Synchrotron Radiation Facility(SSRF) is described. (authors)

  19. Diffraction measurements using the LHC Beam Loss Monitoring System

    Science.gov (United States)

    Kalliokoski, Matti

    2017-03-01

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

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

    CERN Document Server

    Kalliokoski, Matti

    2017-01-01

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

  1. Measurement of Beam Loss at the Australian Synchrotron

    CERN Document Server

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

    2014-01-01

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

  2. Measuring beam losses in the THI project

    International Nuclear Information System (INIS)

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

    1997-01-01

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

  3. Measurement system to detect minute quantity of plutonium and other alpha emitter

    International Nuclear Information System (INIS)

    Simon, G.G.; Eyrich, W.

    1990-01-01

    Presently, the most highly developed method in use is the time correlation analysis method (TCA). With special equipped electronics and computer system designed for the TCA method, the time correlation of the registered events is used to determine the contribution of different multiplets. Thus, the efficiency of the measurement system and the isotopic composition of the probe can be determined and thereby the Plutonium content is calculated. In the case of minute contents of Plutonium, the TCA method is insufficient to calculate the efficiency of the measurement system because of the large statistical error relative to the fluctuation of the background counting rate. This paper reports that in addition to the TCA method, the local correlation analysis (LCA) was developed at the Nuclear Research Center in Karlsruhe (KfK) to yield more information. The efficiency of the measurement system can be calculated taking into account the lifetime of the neutrons in the measurement system and the probe position

  4. Precise half-life measurement of the superallowed β+ emitter 38Km

    International Nuclear Information System (INIS)

    Ball, G. C.; Boisvert, G.; Bricault, P.; Churchman, R.; Dombsky, M.; Lindner, T.; Macdonald, J. A.; Vandervoort, E.; Bishop, S.; D'Auria, J. M.; Hardy, J. C.; Iacob, V. E.; Leslie, J. R.; Mak, H.-B.

    2010-01-01

    The half-life of 38 K m has been measured to be 924.46(14) ms, a result that is a factor of two more precise than any of the five previous measurements of this quantity. The previous results are not consistent with one another, but our result agrees well with the two most recent ones. The derived ft value for 38 K m is now one of the three most precisely known superallowed ft values.

  5. Precise half-life measurement of the superallowed emitter 30S

    Science.gov (United States)

    Iacob, V. E.; Hardy, J. C.; Chen, L.; Horvat, V.; Bencomo, M.; Nica, N.; Park, H. I.; Roeder, B. T.; Saastamoinen, A.

    2018-03-01

    We have measured the half-life of 30S, the parent of a superallowed 0+→0+β transition, to a high precision using very pure sources and a 4 π proportional gas counter to detect the decay positrons. Our result for the half-life is 1.179 92(34) s. As a by-product of this measurement, we determine the half-life of its daughter, 30P, to be 2.501(2) min.

  6. Study on influences of experimental factors on energy and absolute activity measurements of alpha-emitters

    International Nuclear Information System (INIS)

    Terini, R.A.

    1991-01-01

    This work presents firstly a review of the fundamental results and conclusions obtained through alpha-spectrometry and alpha-counting, and the influence of energy straggling, energy loss, self-absorption and backscattering, on the determination of the energy and the absolute activity of alpha samples. Is is shown that the techniques of source fabrication and the methods of measurements play a capital influence on the obtained results. Moreover, measurements made by us, with a silicon surface barrier detector, show that the peak-asymmetry and peak-shift of an alpha-spectrum increases with the angle of emission, and that the magnitude of this effect depends on the thickness and homogeneity of the sample, as well as on the geometry of the measuring system. Through an analysis of the angular distribution of the emitted particles, the degree of isotropy of some thin Am sup(241) sources was measured and the influence of source backing and the geometry was analysed. We can conclude that, in general, there is a larger precision in measurements made under very small solid angles around the normal to the sample, and we enphasize the necessary cares required on the production of the source and on the set up of the measuring system. (author)

  7. Angular-momentum-dominated electron beams and flat-beam generation

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Yin-e [Univ. of Chicago, IL (United States)

    2005-06-01

    In the absence of external forces, if the dynamics within an electron beam is dominated by its angular momentum rather than other effects such as random thermal motion or self Coulomb-repulsive force (i.e., space-charge force), the beam is said to be angular-momentum-dominated. Such a beam can be directly applied to the field of electron-cooling of heavy ions; or it can be manipulated into an electron beam with large transverse emittance ratio, i.e., a flat beam. A flat beam is of interest for high-energy electron-positron colliders or accelerator-based light sources. An angular-momentum-dominated beam is generated at the Fermilab/NICADD photoinjector Laboratory (FNPL) and is accelerated to an energy of 16 MeV. The properties of such a beam is investigated systematically in experiment. The experimental results are in very good agreement with analytical expectations and simulation results. This lays a good foundation for the transformation of an angular-momentum-dominated beam into a flat beam. The round-to-flat beam transformer is composed of three skew quadrupoles. Based on a good knowledge of the angular-momentum-dominated beam, the quadrupoles are set to the proper strengths in order to apply a total torque which removes the angular momentum, resulting in a flat beam. For bunch charge around 0.5 nC, an emittance ratio of 100 ± 5 was measured, with the smaller normalized root-mean-square emittance around 0.4 mm-mrad. Effects limiting the flat-beam emittance ratio are investigated, such as the chromatic effects in the round-to-flat beam transformer, asymmetry in the initial angular-momentum-dominated beam, and space-charge effects. The most important limiting factor turns out to be the uncorrelated emittance growth caused by space charge when the beam energy is low, for example, in the rf gun area. As a result of such emittance growth prior to the round-to-flat beam transformer, the emittance ratio achievable in simulation decreases from orders of thousands to

  8. Emittance growth and tune spectra at PETRA III

    Energy Technology Data Exchange (ETDEWEB)

    Wanzenberg, R.

    2011-08-15

    At DESY the PETRA ring has been converted into a synchrotron radiation facility, called PETRA III. 20 damping wigglers have been installed to achieve an emittance of 1 nm. The commissioning with beam started in April 2009 and user runs have been started in 2010. The design current is 100 mA and the bunch to bunch distance is 8 ns for one particular filling pattern with 960 bunches. At a current of about 50 mA a strong vertical emittance increase has been observed. During machine studies it was found that the emittance increase depends strongly on the bunch filling pattern. For the user operation a filling scheme has been found which mitigates the increase of the vertical emittance. In August 2010 PETRA III has been operated without damping wigglers for one week. The vertical emittance growth was not significantly smaller without wigglers. Furthermore tune spectra at PETRA III show characteristic lines which have been observed at other storage rings in the connection with electron clouds. Measurements at PETRA III are presented for different bunch filling patterns and with and without wiggler magnets. (orig.)

  9. Electron Beam Size Measurements in a Cooling Solenoid

    CERN Document Server

    Kroc, Thomas K; Burov, Alexey; Seletsky, Sergey; Shemyakin, Alexander V

    2005-01-01

    The Fermilab Electron Cooling Project requires a straight trajectory and constant beam size to provide effective cooling of the antiprotons in the Recycler. A measurement system was developed using movable appertures and steering bumps to measure the beam size in a 20 m long, nearly continuous, solenoid. This paper discusses the required beam parameters, the implimentation of the measurement system and results for our application.

  10. Measurements of β or α emitter long lived radionuclides using inductively coupled plasma mass spectrometry

    International Nuclear Information System (INIS)

    Provitina, O.

    1993-01-01

    The measurement of long-lived radionuclides is highly important for characterizing nuclear wastes for their later storage. The main techniques for characterizing these isotopes are α spectrometry, β counting and γ spectrometry. The large period of these isotopes leads to low specific activity needing time consuming measurements in order to obtain significant signals. Moreover, the radiometric techniques are often limited by problems of interferences involving several steps of pretreatments. Among these steps, the specific extraction with crown ethers is highly selective for the separation of 99 Tc, 129 I and 135 Cs particularly. The radiometric techniques are here replaced by inductively coupled plasma mass spectroscopy (ICP-MS) the advantages of which are: few interferences, sensitivity which does not depend on the radiologic period as compared to radiochemistry. ICP-MS can then measure 237 Np in enriched uranium matrix and thereby reduce by a factor of 4 the sample pretreatment and the duration of the analysis usually performed by α spectrometry. Another technique, electrothermal vaporization (ETV), is consequently used. Crown ether extraction-ETV-ICP-MS is employed for measuring the long lived radionuclides 99 Tc and 129 I. The conditions of the extraction and the parameters of the ETV and the ICP-MS are studied and optimized. The methods optimized (extraction, electrothermal vaporization) are validated in the case of 99 Tc, in real samples. The spike method is required to quantify technetium, the quantification with calibration leading to bad results. The results obtained are in good agreement with the expected values. Extraction of technetium on anionic resin and its measurement by the spike method with pneumatic nebulization-ICP-MS is also performed on other samples. Measured values are also in agreement with expected values, but the method of extraction is more time consuming (half a day) than the extraction with crown ether (one hour). (author). 54 figs

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

    CERN Multimedia

    CERN. Geneva

    2014-01-01

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

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

    CERN Multimedia

    CERN. Geneva

    2014-01-01

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

  13. The Citizen Observatory of Radioactivity - Assessment of results - Measurement of gamma emitters. Year 2009

    International Nuclear Information System (INIS)

    2010-01-01

    This document proposes a set of tables containing different information and data regarding measurements of gamma radioactivity made during the first and second half-year of 2009 in different marine and water environments (algae, sands, sea water, molluscs, sediments, water mosses, vegetal) in different locations: a bay close to the AREVA plant in La Hague, different locations on the Normandy coast, around the AREVA plant in La Hague, waterways in Normandy and in other river near the Chinon and Civaux nuclear power stations. These tables contain information about the sampling (date, location, quantity, analysed fraction, and so on) and results of measurements of artificial (isotopes of cobalt, ruthenium-rhodium, silver, iodine, caesium, americium, europium) and natural (potassium, beryllium, lead, bismuth, etc.) radionuclides

  14. Use of proportional gas scintillator in absolute measurements of alpha-gamma emitter activities

    International Nuclear Information System (INIS)

    Tobias, C.C.B.

    1987-01-01

    The absolute activity of U-235 contained in a U 3 O 8 sample was measured utilizing a sum-coincidence circuit which selects only the alpha particles which are simultaneous with the 143 KeV and 186 KeV gamma radiations from the Th-231 (product nucleus). The alpha particles were detected by means of a new type of a gas scintillating chamber, in which the light emitted by excitation of the gas atoms, due to the passage of a charged incoming particle, has its intensity increased by the action of an applied electric field. The gamma radiations were detected by means of a NaI(Tl) 1'' x 1 1/2'' scintillation detector. The value obtained for the half-life of U-235 was compared with the data available from various observers which used different experimental techniques. It is shown tht the results, are in excellent agreement with the best international data available on the subject and that, therefore, the sum-coincidence technique constitutes an important method for such measurements. (Author) [pt

  15. Measurements on wave propagation characteristics of spiraling electron beams

    Science.gov (United States)

    Singh, A.; Getty, W. D.

    1976-01-01

    Dispersion characteristics of cyclotron-harmonic waves propagating on a neutralized spiraling electron beam immersed in a uniform axial magnetic field are studied experimentally. The experimental setup consisted of a vacuum system, an electron-gun corkscrew assembly which produces a 110-eV beam with the desired delta-function velocity distribution, a measurement region where a microwave signal is injected onto the beam to measure wavelengths, and a velocity analyzer for measuring the axial electron velocity. Results of wavelength measurements made at beam currents of 0.15, 1.0, and 2.0 mA are compared with calculated values, and undesirable effects produced by increasing the beam current are discussed. It is concluded that a suitable electron beam for studies of cyclotron-harmonic waves can be generated by the corkscrew device.

  16. Measurement of the absolute activity of alpha or beta emitters by measuring product nuclei (daughter) activity increase or by studing its radioactive decay

    International Nuclear Information System (INIS)

    Campos, L.C. de.

    1981-01-01

    A new method for determining absolute activity of alpha or beta emitters by measuring daughter product radioactive decay is presented. The separation method of UX from hexahydrated uranyl nitrate UO 2 (NO 3 ) 2 6H 2 O based on its dissolution in ethyl ether is described and the accuracy of this method is shown. The factors which accuate on total efficiency of a Geiger Mueller detector for beta particles are determined. The possibility to determine the mass of precursor element by daughter nuclei activity is shown. The results are compared with the one obtained by direct measurement of the mass (or number of atoms) of precursor radioactive substance and with theoretical values calculated for isotopes in secular equilibrium. (Author) [pt

  17. PLS beam position measurement and feedback system

    International Nuclear Information System (INIS)

    Huang, J.Y.; Lee, J.; Park, M.K.; Kim, J.H.; Won, S.C.

    1992-01-01

    A real-time orbit correction system is proposed for the stabilization of beam orbit and photon beam positions in Pohang Light Source. PLS beam position monitoring system is designed to be VMEbus compatible to fit the real-time digital orbit feedback system. A VMEbus based subsystem control computer, Mil-1553B communication network and 12 BPM/PS machine interface units constitute digital part of the feedback system. With the super-stable PLS correction magnet power supply, power line frequency noise is almost filtered out and the dominant spectra of beam obtit fluctuations are expected to appear below 15 Hz. Using DSP board in SCC for the computation and using an appropriate compensation circuit for the phase delay by the vacuum chamber, PLS real-time orbit correction system is realizable without changing the basic structure of PLS computer control system. (author)

  18. Generating and measuring nondiffracting vector Bessel beams

    CSIR Research Space (South Africa)

    Dudley, Angela L

    2013-09-01

    Full Text Available Nondiffracting vector Bessel beams are of considerable interest due to their nondiffracting nature and unique high-numerical-aperture focusing properties. Here we demonstrate their creation by a simple procedure requiring only a spatial light...

  19. Beam-Profile Instrumentation for a Beam-Halo Measurement Overall Description, Operation, and Beam Data

    CERN Document Server

    Gilpatrick, J D; Day, L; Kerstiens, D; Stettler, M; Valdiviez, R

    2001-01-01

    The halo experiment presently being conducted at the Low Energy Demonstration Accelerator (LEDA) at Los Alamos National Laboratory (LANL) has specific instruments that acquire horizontally and vertically projected particle-density beam distributions out to greater than 105:1 dynamic range. We measure the core of the distributions using traditional wire scanners, and the tails of the distribution using water-cooled graphite scraping devices. The wire scanner and halo scrapers are mounted on the same moving frame whose location is controlled with stepper motors. A sequence within the Experimental Physics and Industrial Control System (EPICS) software communicates with a National Instrument LabVIEW virtual instrument to control the movement and location of the scanner/scraper assembly. Secondary electrons from the wire scanner 33 μm carbon wire and protons impinging on the scraper are both detected with a lossy-integrator electronic circuit. Algorithms implemented within EPICS and in Research Systems Interactiv...

  20. Measurement of centroid trajectory of Dragon-I electron beam

    International Nuclear Information System (INIS)

    Jiang Xiaoguo; Wang Yuan; Zhang Wenwei; Zhang Kaizhi; Li Jing; Li Chenggang; Yang Guojun

    2005-01-01

    The control of the electron beam in an intense current linear induction accelerator (LIA) is very important. The center position of the electron beam and the beam profile are two important parameters which should be measured accurately. The setup of a time-resolved measurement system and a data processing method for determining the beam center position are introduced for the purpose of obtaining Dragon-I electron beam trajectory including beam profile. The actual results show that the centroid position error can be controlled in one to two pixels. the time-resolved beam centroid trajectory of Dragon-I (18.5 MeV, 2 kA, 90 ns) is obtained recently in 10 ns interval, 3 ns exposure time with a multi-frame gated camera. The results show that the screw movement of the electron beam is mainly limited in an area with a radius of 0.5 mm and the time-resolved diameters of the beam are 8.4 mm, 8.8 mm, 8.5 mm, 9.3 mm and 7.6 mm. These results have provided a very important support to several research areas such as beam trajectory tuning and beam transmission. (authors)

  1. OBSERVATION OF STRONG - STRONG AND OTHER BEAM - BEAM EFFECTS IN RHIC

    International Nuclear Information System (INIS)

    FISCHER, W.; BLASKIEWICZ, M.; BRENNAN, J.M.; CAMERON, P.; CONNOLLY, R.; MONTAG, C.; PEGGS, S.; PILAT, F.; PTITSYN, V.; TEPIKIAN, S.; TRBOJEVIC, D.; VAN ZEIJTS, J.

    2003-01-01

    RHIC is currently the only hadron collider in which strong-strong beam-beam effects can be seen. For the first time, coherent beam-beam modes were observed in a bunched beam hadron collider. Other beam-beam effects in RHIC were observed in operation and in dedicated experiments with gold ions, deuterons and protons. Observations include measurements of beam-beam induced tune shifts, lifetime and emittance growth measurements with and without beam-beam interaction, and background rates as a function of tunes. During ramps unequal radio frequencies in the two rings cause the crossing points to move longitudinally. Thus bunches experience beam-beam interactions only in intervals and the tunes are modulated. In this article we summarize the most important beam-beam observations made so far

  2. A beam energy measurement system at NIRS-930 cyclotron

    International Nuclear Information System (INIS)

    Hojo, S.; Honma, T.; Sakamoto, Y.; Miyahara, N.; Okada, T.; Komatsu, K.; Tsuji, N.; Yamada, S.

    2005-01-01

    A beam energy measurement system employing a set of capacitive probes has been developed at NIRS-930 cyclotron. Principle of the measurement is applying a modified-TOF method, so that the two proves are installed at one of the straight section in the beam transport line. Usually they are separated about 5.8 m, which is equivalent to the almost final path length of the beam extracted in the cyclotron. In the measurement, two beam signals are superimposed by adjusting a position of the downstream-probe along the beam direction with watching an oscilloscope screen roughly. In order to determine the beam energy accurately the signals are processed by MCA with suitable electric module. (author)

  3. Room-temperature deposition of diamond-like carbon field emitter on flexible substrates

    International Nuclear Information System (INIS)

    Chen, H.; Iliev, M.N.; Liu, J.R.; Ma, K.B.; Chu, W.-K.; Badi, N.; Bensaoula, A.; Svedberg, E.B.

    2006-01-01

    Room-temperature fabrication of diamond-like carbon electron field emitters on flexible polyimide substrate is reported. These thin film field emitters are made using an Ar gas cluster ion beam assisted C 6 vapor deposition method. The bond structure of the as-deposited diamond-like carbon film was studied using Raman spectroscopy. The field emission characteristics of the deposited films were also measured. Electron current densities over 15 mA/cm 2 have been recorded under an electrical field of about 65 V/μm. These diamond-like carbon field emitters are easy and inexpensive to fabricate. The results are promising for flexible field-emission fabrication without the need of complex patterning and tip shaping as compared to the Spindt-type field emitters

  4. Emittance studies of high intensity negative ion sources equipped with continuous surface cylindrical and spherical geometry tungsten ionizers

    International Nuclear Information System (INIS)

    Alton, G.D.; McConnell, J.W.; Tajima, S.; Nelson, G.S.

    1986-01-01

    A digitally controlled emittance measurement, data acquisition and processing system has been designed, implemented and used to determine emittances of negative ion beams extracted from high-intensity negative-ion sources equipped with cylindrical and spherical geometry cesium surface ionizers. Comparative studies indicate that the emittances of ion beams extracted from the source equipped with a spherical geometry ionizer are lower by 13% to 21% than those extracted from the source equipped with a cylindrical geometry ionizer. This difference may be attributable to geometric factors rather than differences in the sizes of the emission areas at the points of negative-ion generation. Studies reveal that the emittances of these sources are independent of ion mass for most of the materials investigated and independent of ion current over the range of ion currents used in these investigations (4μA to 12 μA)

  5. Measurement of beam energy spread in a space-charge dominated electron beam

    Directory of Open Access Journals (Sweden)

    Y. Cui

    2004-07-01

    Full Text Available Characterization of beam energy spread in a space-charge dominated beam is very important to understanding the physics of intense beams. It is believed that coupling between the transverse and longitudinal directions via Coulomb collisions will cause an increase of the beam longitudinal energy spread. At the University of Maryland, experiments have been carried out to study the energy evolution in such intense beams with a high-resolution retarding field energy analyzer. The temporal beam energy profile along the beam pulse has been characterized at the distance of 25 cm from the anode of a gridded thermionic electron gun. The mean energy of the pulsed beams including the head and tail is reported here. The measured rms energy spread is in good agreement with the predictions of the intrabeam scattering theory. As an application of the beam energy measurement, the input impedance between the cathode and the grid due to beam loading can be calculated and the impedance number is found to be a constant in the operation region of the gun.

  6. Bipolar junction transistor as a detector for measuring in diagnostic X-ray beams

    Energy Technology Data Exchange (ETDEWEB)

    Cavalcanti, Francisco A.; Monte, David S.; Alves, Aline N.; Barros, Fabio R.; Santos, Marcus A.P.; Santos, Luiz A.P., E-mail: franciscoacavalcanti@gmail.com, E-mail: lasantos@cnen.gov.br [Centro Regional de Ciencias Nucleares do Nordeste (CRCN-NE/CNEN-PE), Recife, PE (Brazil)

    2013-07-01

    Photodiode and phototransistor are the most frequently used devices for measuring ionizing radiation in medical applications. The cited devices have the operating principle well known, however the bipolar junction transistor (BJT) is not a typical device used as a detector for measuring some physical quantities for diagnostic radiation. In fact, a photodiode, for example, has an area about 10 mm square and a BJT has an area which can be more than 10 thousands times smaller. The purpose of this paper is to bring a new technique to estimate some physical quantities or parameters in diagnostic radiation; for example, peak kilovoltage (kVp), deep dose measurements. The methodology for each type of evaluation depends on the energy range of the radiation and the physical quantity or parameter to be measured. Actually, some characteristics of the incident radiation under the device can be correlated with the readout signal, which is a function of the electrical currents in the electrodes of the BJT: Collector, Base and Emitter. Samples of BJT are classified and submitted to diagnostic X-ray beams. The results show that the BJT could be a new semiconductor sensor type for measuring either the ionizing radiation dose or some characteristics of diagnostic X-ray beams. (author)

  7. Measuring the electron beam energy in a magnetic bunch compressor

    Energy Technology Data Exchange (ETDEWEB)

    Hacker, Kirsten

    2010-09-15

    Within this thesis, work was carried out in and around the first bunch compressor chicane of the FLASH (Free-electron LASer in Hamburg) linear accelerator in which two distinct systems were developed for the measurement of an electron beams' position with sub-5 {mu}m precision over a 10 cm range. One of these two systems utilized RF techniques to measure the difference between the arrival-times of two broadband electrical pulses generated by the passage of the electron beam adjacent to a pickup antenna. The other system measured the arrival-times of the pulses from the pickup with an optical technique dependent on the delivery of laser pulses which are synchronized to the RF reference of the machine. The relative advantages and disadvantages of these two techniques are explored and compared to other available approaches to measure the same beam property, including a time-of-flight measurement with two beam arrival-time monitors and a synchrotron light monitor with two photomultiplier tubes. The electron beam position measurement is required as part of a measurement of the electron beam energy and could be used in an intra-bunch-train beam-based feedback system that would stabilize the amplitude of the accelerating field. By stabilizing the accelerating field amplitude, the arrival-time of the electron beam can be made more stable. By stabilizing the electron beam arrival-time relative to a stable reference, diagnostic, seeding, and beam-manipulation lasers can be synchronized to the beam. (orig.)

  8. Measurement of deuteron beam polarization before and after acceleration

    Directory of Open Access Journals (Sweden)

    A Ramazani Moghaddam Arani

    2017-02-01

    Full Text Available Beam polarization measurement in scattering experiments with a high accuracy and the lowest possible cost is an important issue. In this regard, deuteron beam polarization was measured in the low-energy beam line easily with a relatively low cost procedure and in a very short time by Lamb Shift Polarimeter (LSP. Also, the beam polarization has been measured in high-energy beam line with BINA. In low-energy line, a polarized beam of deuterons delivered by POLIS was decelerated and focused on LSP detection system. Three resonances between 52mT and 63mT show the distribution of different spin states of polarized deuteron beam. In high-energy beam line, polarization can be measured employing BINA via the H(d,dp reaction. The asymmetry ratio, was obtained as a function of azimuthal angle, φ, for several polar scattering angles. Knowing values of the analyzing powers, the ratio has been used to extract the polarization results. The obtained results show that polarization of deuteron beam that is accelerated up to the energy of 130 MeV is almost the same before and after acceleration

  9. Designing Light Beam Transmittance Measuring Tool Using a Laser Pointer

    Science.gov (United States)

    Nuroso, H.; Kurniawan, W.; Marwoto, P.

    2016-08-01

    A simple instrument used for measuring light beam transmittance percentage made of window film has been developed. The instrument uses a laser pointer of 405 nm and 650 nm ±10% as a light source. Its accuracy approaches 80%. Transmittance data was found by comparing the light beam before and after passing the window film. The light intensity measuring unit was deleted by splitting the light source into two beams through a beam splitter. The light beam was changed into resistance by a NORP12 LDR sensor designed at a circuit of voltage divider rule of Khirchoff's laws. This conversion system will produce light beam intensity received by the sensor to become an equal voltage. This voltage will, then, be presented on the computer screen in the form of a real time graph via a 2.0 USB data transfer.

  10. The Quantum Efficiency and Thermal Emittance of Metal Photocathodes

    International Nuclear Information System (INIS)

    Dowell, D.

    2009-01-01

    Modern electron beams have demonstrated the brilliance needed to drive free electron lasers at x-ray wavelengths, with the principle improvements occurring since the invention of the photocathode gun. The state-of-the-art normalized emittance electron beams are now becoming limited by the thermal emittance of the cathode. In both DC and RF photocathode guns, details of the cathode emission physics strongly influence the quantum efficiency and the thermal emittance. Therefore improving cathode performance is essential to increasing the brightness of beams. It is especially important to understand the fundamentals of cathode quantum efficiency and thermal emittance. This paper investigates the relationship between the quantum efficiency and the thermal emittance of metal cathodes using the Fermi-Dirac model for the electron distribution. We derive the thermal emittance and its relationship to the quantum efficiency, and compare our results to those of others

  11. Beam size measurement of the stored electron beam at the APS storage ring using pinhole optics

    International Nuclear Information System (INIS)

    Cai, Z.; Lai, B.; Yun, W.

    1995-01-01

    Beam sizes of the stored electron beam at the APS storage ring were measured using pinhole optics and bending magnet x-rays in single-bunch and low-current mode. A pinhole of 25 μm and a fast x-ray imaging system were located 23.8 m and 35.4 m from the source, respectively. The x-ray imaging system consists of a CdWO 4 scintillation crystal 60 μm thick, an optical imaging system, and a CCD detector. A measurement time of a few tenths of a second was obtained on a photon beam of E>30 keV produced in a bending magnet from a 7-GeV electron beam of 2mA current. The measured vertical and horizontal sizes of the electron beam were in reasonable agreement with the expected values

  12. The first experience with LHC beam gas ionization monitor

    CERN Document Server

    Sapinski, M; Dehning, B; Guerrero, A; Patecki, M; Versteegen, R

    2012-01-01

    The Beam Gas Ionization Monitors (BGI) are used to measure beam emittance on LHC. This paper describes the detectors and their operation and discusses the issues met during the commissioning. It also discusses the various calibration procedures used to correct for non-uniformity of Multi-Channel plates and to correct the beam size for effects affecting the electron trajectory after ionization.

  13. Measurement of power density distribution and beam waist simulation for electron beam

    International Nuclear Information System (INIS)

    Shen, Chunlong; Peng, Yong; Wang, Kehong; Zhou, Qi

    2013-01-01

    The study aims to measure the power density distribution of the electron beam (EB) for further estimating its characteristics. A compact device combining deflection signal controller and current signal acquisition circuit of the EB was built. A software modelling framework was developed to investigate structural parameters of the electron beam. With an iterative algorithm, the functional relationship between the electron beam power and its power density was solved and the corresponding contour map of power density distribution was plotted through isoline tracking approach. The power density distribution of various layers of cross-section beam was reconstructed for beam volume by direct volume rendering technique. The further simulation of beam waist with all-known marching cubes algorithm reveals the evolution of spatial appearance and geometry measurement principle was explained in detail. The study provides an evaluation of promising to replace the traditional idea of EB spatial characteristics. - Highlights: ► We build a framework for measuring power density distribution for electron beam. ► We capture actual electron and build transient spatial power distribution for EB. ► Tracing algorithm of power density contour for cross-section was designed. ► The volume and waist of the beam are reconstructed in 4D mode. ► Geometry measurement is finished which is befit for designing of process welding.

  14. Neutralization of H- beams by magnetic stripping

    International Nuclear Information System (INIS)

    Jason, A.J.; Hudgings, D.W.; van Dyck, O.B.

    1981-01-01

    The stability of H - beams passing through strong magnetic fields has been relevant to accelerator transport problems and, recently, to neutral beam preparation techniques. The H - electron detachment rate was measured as a function of rest-frame electric field and provides parameters for a theoretical lifetime expression. The limitations imposed on H - transport by magnetic stripping, and neutral-beam preparation in emittance growth, magnetic fields, and beam energies are discussed. Application techniques are also briefly discussed

  15. Polarisation measurements on e sup+- beams

    CERN Document Server

    Long, K

    2002-01-01

    The current status of e sup+--beam polarimetry at the HERA ep collider is reviewed, giving the performance achieved to date and the status of the various upgrade projects together with a summary of the expected performance. In addition, the polarimeter that has been proposed for the TESLA e sup + e sup - collider is described.

  16. The single-beam funnel demonstration: Experiment and simulation

    International Nuclear Information System (INIS)

    Johnson, K.F.; Sander, O.R.; Bolme, G.O.; Gilpatrick, J.D.; Guy, F.W.; Marquardt, J.H.; Sandoval, D.; Yuan, V.; Saadatmand, K.

    1991-01-01

    Accelerator concepts for heavy-ion fusion and for the transmutation of nuclear waste require small-emittance, high-current beams. Such applications include funnels in which high-current, like-charged particle beams are interlaced to double the beam current. The first experimental demonstration confirming the beam dynamics of the funnel principle (with contained emittance growth) was recently completed at Los Alamos National Laboratory. A single leg of a prototype 5-MeV, H - funnel was successfully tested. This single-beam demonstration explored physics issues of a two-beam funnel. The experiment contained elements for emittance control, position control, and rf-deflection. Diagnostics allowed measurement of beam intensity, position and angle centroids, energy and phase centroids, transverse and longitudinal phase-space distributions. Results of the experiment will be presented along with comparisons to simulations

  17. B-dot monitor for intense electron beam measurement

    International Nuclear Information System (INIS)

    Li Qin; Li Hong; Chen Nan; Gao Feng; Wang Yongwei; Wang Liping

    2009-01-01

    Azimuthal arrays of B-dot loops are often used to measure the time-resolved beam centroid position of a pulsed, intense electron beam propagating in a metallic tube. This paper describes the designing principle, parameters and calibration of the B-dot monitors. According to the beam current pulse rise time, fall time and the pulse width, the B-dot is designed to work as a differential loop, the loop inductance is about 60 nH. The B-dot monitor's sensitivity and the displacement curve are calibrated in the test stand. The sensitivity of the B-dots and the passive RC integrator is averagely 4 147 A/V, integrate constant is about 1 μs. The B-dot monitors are used to measure the Dragon-I electron beam and the experimental results show that the B-dot monitors can measure the beam current and centroid position accurately. (authors)

  18. Metastable atom probe for measuring electron beam density profiles

    Science.gov (United States)

    Lockhart, J. M.; Zorn, J. C.

    1972-01-01

    Metastable atom probe was developed for measuring current density in electron beam as function of two arbitrary coordinates, with spatial resolution better than 0.5 mm. Probe shows effects of space charge, magnetic fields, and other factors which influence electron current density, but operates with such low beam densities that introduced perturbation is very small.

  19. Laser Beam Caustic Measurement with Focal Spot Analyser

    DEFF Research Database (Denmark)

    Olsen, Flemming Ove; Gong, Hui; Bagger, Claus

    2005-01-01

    In industrial applications of high power CO2-lasers the caustic characteristics of the laser beam have great effects on the performance of the lasers. A welldefined high intense focused spot is essential for reliable production results. This paper presents a focal spot analyser that is developed...... for measuring the beam profiles of focused high power CO2-lasers....

  20. Beam Shaping for CARS Measurements in Turbulent Environments

    Science.gov (United States)

    Magnotti, Gaetano; Cutler, Andrew D.; Danehy, Paul M.

    2010-01-01

    This paper describes a new technique to mitigate the effect of beam steering on CARS measurements in turbulent, variable density environments. The new approach combines Planar BOXCARS phase-matching with elliptical shaping of one of the beams to generate a signal insensitive to beam steering, while keeping the same spatial resolution. Numerical and experimental results are provided to demonstrate the effectiveness of this approach. One set of experiments investigated the effect of beam shaping in the presence of a controlled and well quantified displacement of the beams at the focal plane. Another set of experiments, more qualitative, proved the effectiveness of the technique in the presence of severe beam steering due to turbulence.

  1. 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.

  2. Measurements with radioactive beams at ATLAS.

    Energy Technology Data Exchange (ETDEWEB)

    Rehm, K. E.

    1998-08-06

    Reactions of interest to nuclear astrophysics have been studied with radioactive beams at the ATLAS accelerator. Using a modified ISOL technique, beams of {sup 18}F (T{sub 1/2} = 110 min) and {sup 56}Ni (T{sub 1/2} = 6.1d) were produced and the reactions {sup 18}F(p,{alpha}){sup 15}O, {sup 18}F(p,{gamma}){sup 19}Ne, and {sup 56}Ni(d,p){sup 57}Ni have been investigated. The results indicate that the {sup 18}F(p,{gamma}) route is a small contributor to the breakout from the hot CNO cycle into the rp process, while the {sup 56}Ni(p,{gamma}){sup 57}Cu rate is about ten times larger than previously assumed.

  3. Measurement of Beam Lifetime and Applications for SPEAR3

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Xiaobiao; Corbett, Jeff; /SLAC

    2011-04-05

    Beam lifetime studies for the SPEAR3 storage ring are presented. The three lifetime components are separated with lifetime measurements under various combinations of beam currents and fill patterns and vertical scraper scans. Touschek lifetime is studied with rf voltage scans and with the horizontal or vertical scrapers inserted. The measurements are explained with calculations based on the calibrated lattice model. Quantum lifetime measurements are performed with reduced longitudinal and horizontal apertures, respectively, from which we deduce the radiation energy loss down to a few keV per revolution and the horizontal beam size.

  4. Measurement system with high accuracy for laser beam quality.

    Science.gov (United States)

    Ke, Yi; Zeng, Ciling; Xie, Peiyuan; Jiang, Qingshan; Liang, Ke; Yang, Zhenyu; Zhao, Ming

    2015-05-20

    Presently, most of the laser beam quality measurement system collimates the optical path manually with low efficiency and low repeatability. To solve these problems, this paper proposed a new collimated method to improve the reliability and accuracy of the measurement results. The system accuracy controlled the position of the mirror to change laser beam propagation direction, which can realize the beam perpendicularly incident to the photosurface of camera. The experiment results show that the proposed system has good repeatability and the measuring deviation of M2 factor is less than 0.6%.

  5. Emittance scans for CMS luminosity calibration in 2017

    CERN Document Server

    CMS Collaboration

    2018-01-01

    Emittance scans are short van der Meer type scans performed at the beginning and at the end of LHC fills. The beams are scanned against each other in X and Y planes in 7 displacement steps. These scans are used for LHC diagnostics and since 2017 for a cross check of the CMS luminosity calibration. An XY pair of scans takes around 3 minutes. The BRIL project provides to LHC three independent online luminosity measurement from the Pixel Luminosity Telescope (PLT), the Fast Beam Condition Monitor (BCM1F) and the Forward calorimeter (HF). The excellent performance of the BRIL detector front-ends, fast back-end electronics and CMS XDAQ based data processing and publication allow the use of emittance scans for linearity and stability studies of the luminometers. Emittance scans became a powerful tool and dramatically improved the understanding of the luminosity measurement during the year. Since each luminometer is independently calibrated in every scan the measurements are independent and ratios of luminometers ca...

  6. The Electroluminescence Mechanism of Solution-Processed TADF Emitter 4CzIPN Doped OLEDs Investigated by Transient Measurements

    Directory of Open Access Journals (Sweden)

    Peng Wang

    2016-10-01

    Full Text Available High efficiency, solution-processed, organic light emitting devices (OLEDs, using a thermally-activated delayed fluorescent (TADF emitter, 1,2,3,5-tetrakis(carbazol-9-yl-4,6-dicyanobenzene (4CzIPN, are fabricated, and the transient electroluminescence (EL decay of the device with a structure of [ITO/PEDOT: PSS/4CzIPN 5 wt % doped 4,40-N,N0-dicarbazolylbiphenyl(CBP/bis-4,6-(3,5-di-4-pyridylphenyl-2-methylpyrimidine (B4PyMPM/lithium fluoride (LiF/Al], is systematically studied. The results shed light on the dominant operating mechanism in TADF-based OLEDs. Electroluminescence in the host–guest system is mainly produced from the 4CzIPN emitter, rather than the exciplex host materials.

  7. Measuring Beam Quality of Hollow Core Photonic Crystal Fibers

    DEFF Research Database (Denmark)

    Shephard, J.D.; Roberts, John; Jones, J.D.C.

    2006-01-01

    In this paper, the authors measure the quality of the delivered beam from hollow core photonic crystal fibers (HC-PCFs). The$M^2$parameter is determined, and the near- to far-field transition is examined. The influence on these properties due to the presence of a core surround mode is evaluated....... The applicability of the International Standards Organization 11146 : 1999 standard for$M^2$measurement of the beam quality of HC-PCFs is discussed. Because they are dependent on the measurement parameters, such as choice of aperturing scheme and the axis of measurement,$M^2$values could vary from 1.32 to 3.......17 for the same output beam. This highlights the need for careful consideration when measuring and describing the beam quality delivered by these novel photonic fibers....

  8. Beam Optics Measurements Through Turn by Turn Beam Position Data in the SLS

    CERN Document Server

    Zisopoulos, P; Streun, A; Ziemann, v

    2013-01-01

    Refined Fourier analysis of turn-by-turn (TBT) transverse position data measurements can be used for determining several beam properties of a ring, such as transverse tunes, optics functions, phases, chromatic properties and coupling. In particular, the Numerical Analysis of Fundamental Frequencies (NAFF) algorithm is used to analyse TBT data from the Swiss Light Source (SLS) storage ring in order to estimate on and off-momentum beam characteristics. Of particular interest is the potential of using the full position information within one turn in order to measure beam optics properties.

  9. Extracted-beam-detection system around synchrotron saturne

    International Nuclear Information System (INIS)

    Anne, Remy; Milleret, Gerard; Giuliani, Arlette; Lefol, Andre; Perret, Robert; Poupard, Joseph; Trogno, Andre; Van den Bossche, Maurice; N'Guyen Sieu Viet.

    1977-07-01

    The extracted-beam-detection system working around the synchrotron Saturne is presented. The whole system is composed of about forty multiwire chambers used for beam tuning and providing beams profiles. Optic beam parameters such as position, divergence, dimension, emittance can be easily measured, or calculated with a program running on a computer. They are working in large range intensity beams (10 2 to 5.10 11 p/cm 2 /s of protons, alpha particles, deutons, pions, tritons and electrons [fr

  10. Measurement of beam energy spectrum and impurity content in high-power neutral beam injectors

    International Nuclear Information System (INIS)

    Langley, R.A.; Ryan, P.M.; Tsai, C.C.; Menon, M.M.; Botnick, E.M.; Magee, C.W.

    1985-01-01

    The energy spectrum and impurity content of a high-power neutral beam are measured by implanting the beam into high-purity silicon crystals. The depth distribution of the beam particles is then measured by secondary ion mass spectrometry (SIMS); the penetration depth is a function of the incident particle energy. This is one of the few measurement techniques that can determine neutral beam energy components directly. From the results, percentages of atomic and molecular ions in the source plasma can be inferred. Use of deuterium as the source gas provides insight into the role of residual hydrogen in the ion source and accelerating grids and in the SIMS analysis. The principal impurities are carbon and oxygen. Preliminary data indicate that carbon can originate from both methane and carbon monoxide, while oxygen can come from molecular oxygen, carbon monoxide, and water. Results are given and future plans are discussed

  11. Beam Based RF Voltage Measurements and Longitudinal Beam Tomography at the Fermilab Booster

    Energy Technology Data Exchange (ETDEWEB)

    Bhat, C. M. [Fermilab; Bhat, S. [Fermilab

    2017-10-19

    Increasing proton beam power on neutrino production targets is one of the major goals of the Fermilab long term accelerator programs. In this effort, the Fermilab 8 GeV Booster synchrotron plays a critical role for at least the next two decades. Therefore, understanding the Booster in great detail is important as we continue to improve its performance. For example, it is important to know accurately the available RF power in the Booster by carrying out beam-based measurements in order to specify the needed upgrades to the Booster RF system. Since the Booster magnetic field is changing continuously measuring/calibrating the RF voltage is not a trivial task. Here, we present a beam based method for the RF voltage measurements. Data analysis is carried out using computer programs developed in Python and MATLAB. The method presented here is applicable to any RCS which do not have flat-bottom and flat-top in the acceleration magnetic ramps. We have also carried out longitudinal beam tomography at injection and extraction energies with the data used for RF voltage measurements. Beam based RF voltage measurements and beam tomography were never done before for the Fermilab Booster. The results from these investigations will be very useful in future intensity upgrades.

  12. Study of instabilities and emittance growth in periodic focusing systems for intense beams. Technical report No. PP 82-142. Progress report

    International Nuclear Information System (INIS)

    Reiser, M.

    1982-03-01

    Experimental studies of beam properties and nonlinear effects with one and two solenoid lenses have yielded a large amount of valuable data. Several phenomena were identified and explored such as images and halos and formation of pronounced hollow beam profiles after passage through the lenses. The hollow beam effect is qualitatively attributed to nonlinear space charge forces and lens aberrations. The main research effort during the past year was devoted to the experimental investigation of beam focusing with one and two solenoid lenses

  13. Precision luminosity measurement at LHCb with beam-gas imaging

    International Nuclear Information System (INIS)

    Barschel, Colin

    2014-01-01

    The luminosity is the physical quantity which relates the cross-section to the production rate in collider experiments. The cross-section being the particle physics observable of interest, a precise determination of the luminosity is required. This work presents the absolute luminosity calibration results performed at the Large Hadron Collider beauty (LHCb) experiment at CERN using a novel method based on beam-gas interactions with data acquired at a center of mass energy √(s)=8 TeV and √(s)=2.76 TeV. Reconstructed beam-gas interaction vertices in LHCb are used to measure the beam profiles, thus making it possible to determine the beams overlap integral. An important element of this work was to install and use a neon gas injection system to increase the beam-gas interaction rate. The precision reached with the beam-gas imaging method relies on the two-dimensional beam shape determination developed in this work. For such precision, the interaction vertex resolution is an important ingredient. Therefore, a new method has been developed using all reconstructed vertices in order to improve the understanding of the vertex resolution. In addition to the overlap integral, the knowledge of the colliding bunch populations is required to measure the luminosity. The determination of the bunch populations relies on LHC instruments to measure the bunch population fractions and the total beam intensity. Studies performed as part of this work resulted in a reduction of the bunch current normalization uncertainty from ±2.7% to ±0.2% and making it possible to achieve precision luminosity measurements at all LHC experiments. Furthermore, information on beam-gas interactions not originating from nominally filled bunches was analyzed to determine the charge fraction not participating in bunch collisions. The knowledge of this fraction is required to correct the total beam intensity. The reference cross-section of pp interactions with at least two tracks in the vertex detector

  14. Emittance variations in current-amplifying ion induction linacs

    International Nuclear Information System (INIS)

    Fessenden, T.J.

    1991-01-01

    Since 1985 the Heavy Ion Fusion Accelerator Research program at the Lawrence Berkeley Laboratory has been studying current amplification and emittance variations in MBE-4, a four-cesium-beam induction linac. This experiment models much of the accelerator physics of the electrostatically focused section of a fusion driver. Four space-charge dominated Cs + beams, initially about one meter in length at currents of 5-10 mA, are focused by electrostatic quadrupoles and accelerated in parallel from approximately 200 keV up to one MeV by 24 accelerating gaps. Final currents of 20-40 mA per beam are typical. Recent experiments with extremely low emittance beams (var-epsilon n =0.03 mm-mRad) have investigated variations of transverse and longitudinal normalized emittance for drifting and accelerating beams. These very strongly tune-depressed beams (σ 0 =72 degree, σ∼6 degree) are difficult to match to the accelerator so as to avoid emittance growth during acceleration. During transport strong emittance fluctuations are observed in good qualitative agreement with simulations. Warmer beams with less tune depression exhibit little to no emittance growth, show smaller emittance fluctuations, and are much easier to match. A summary of findings from the MBE-4 studies is presented

  15. Emittance variations in current-amplifying ion induction linacs

    International Nuclear Information System (INIS)

    Fessenden, T.J.

    1991-04-01

    Since 1985 the Heavy Ion Fusion Accelerator Research program at the Lawrence Berkeley Laboratory has been studying current amplification and emittance variations in MBE-4, a four-cesium-beam induction linac. This experiment models much of the accelerator physics of the electrostatically focused section of a fusion driver. Four space-charge dominated Cs + beams, initially about one meter in length at currents of 5--10 mA, are focused by electrostatic quadrupoles and accelerated in parallel from approximately 200 keV up to one MeV by 24 accelerating gaps. Final currents of 20--40 mA per beam are typical. Recent experiments with extremely low emittance beams (ε n = 0.03 mm-mRad) have investigated variations of transverse and longitudinal normalized emittance for drifting and accelerating beams. These very strongly tune-depressed beams (σ o = 72 degrees, σ∼6 degree) are difficult to match the accelerator so as to avoid emittance growth during acceleration. During transport strong emittance fluctuations are observed in good qualitative agreement with simulations. Warmer beams with less tune depression exhibit little to no emittance growth, show smaller emittance fluctuations, and are much easier to match. A summary of findings from the MBE-4 studies is presented. 12 refs., 8 figs

  16. Measurements of beam halo diffusion and population density in the Tevatron and in the Large Hadron Collider

    Energy Technology Data Exchange (ETDEWEB)

    Stancari, Giulio [Fermilab

    2015-03-01

    Halo dynamics influences global accelerator performance: beam lifetimes, emittance growth, dynamic aperture, and collimation efficiency. Halo monitoring and control are also critical for the operation of high-power machines. For instance, in the high-luminosity upgrade of the LHC, the energy stored in the beam tails may reach several megajoules. Fast losses can result in superconducting magnet quenches, magnet damage, or even collimator deformation. The need arises to measure the beam halo and to remove it at controllable rates. In the Tevatron and in the LHC, halo population densities and diffusivities were measured with collimator scans by observing the time evolution of losses following small inward or outward collimator steps, under different experimental conditions: with single beams and in collision, and, in the case of the Tevatron, with a hollow electron lens acting on a subset of bunches. After the LHC resumes operations, it is planned to compare measured diffusivities with the known strength of transverse damper excitations. New proposals for nondestructive halo population density measurements are also briefly discussed.

  17. 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.

  18. Application of virtual instrument in accelerator beam measurement system

    International Nuclear Information System (INIS)

    Huang Guoqing; China Science and Technology Univ., Hefei; Yu Xiaoqi; Zhang Pengfei

    2007-01-01

    Virtual instrument is a novel computer-based technical method of measurement, which has got rapidly development and has been applied in many fields because of a variety of advantages. In this paper we mainly introduce application of virtual instrument in accelerator beam measurement system. Beam measurement system is an important part of accelerator technology and has important effect on accelerator debugging, running and machine research. Adopting new measurement methods and increasing accuracy of measurement directly affect accelerator debugging and running. Now many accelerators have been adopted virtual instrument system. (authors)

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

    CERN Document Server

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

    2013-01-01

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

  20. Laser alignment measurement model with double beam

    Science.gov (United States)

    Mo, Changtao; Zhang, Lili; Hou, Xianglin; Wang, Ming; Lv, Jia; Du, Xin; He, Ping

    2012-10-01

    Double LD-Double PSD schedule.employ a symmetric structure and there are a laser and a PSD receiver on each axis. The Double LD-Double PSD is used, and the rectangular coordinate system is set up by use of the relationship of arbitrary two points coordinates, and then the parameter formula is deduced by the knowledge of solid geometry. Using the data acquisition system and the data processing model of laser alignment meter with double laser beam and two detector , basing on the installation parameter of the computer, we can have the state parameter between the two shafts by more complicated calculation and correction. The correcting data of the four under chassis of the adjusted apparatus moving on the level and the vertical plane can be calculated using the computer. This will instruct us to move the apparatus to align the shafts.

  1. Parallel beam scanning system for flatness measurements of thin plates

    Science.gov (United States)

    Fan, Kuang-Chao; Wu, John H.

    1993-09-01

    This paper describes the work to develop a Parallel Beam Scanning System (PBSS) for the non-contact measurement of surface flatness of thin plates. The PBSS consists of a He-Ne laser source having good pointing stability a scanner to create divergent scanning beams a large aplanatic meniscus lens to convert the divergent beams to parallel beams a linear stage to drive the testpiece to each sampling position a screen for the projection of reflected beams from the tested surface and an image processing unit to analyze the projected image. Due to the out-of-flatness of the surface the straight line formed by the incident parallel beams will be distorted and magnified on the screen as it is reflected from the tested surface. The stage then positions the testpiece step-by-step to carry out measurements in the line-by-line sequence. A CCD camera is employed to capture the image of the distorted line on the screen each time. With the proposed mathematical model the flatness data of the testpiece can be computed from the input image data. Experimental results by the use of this system have shown in good agreement with the results obtained from the coordinate measuring machine. This system can be applied to the flatness measurements of thin plates such as sheet metals sheet moulding compound (SMC) plates glass plates etc. which are difficult to measure by traditional methods.

  2. Deviation in the predefined calibration factors of the dose calibrators and the associated inaccuracy in the radioactivity measurements of beta-gamma emitters

    International Nuclear Information System (INIS)

    Sharma, Sarika; Singh, Baljinder; Koul, Ashwani; Mittal, Bhagwant Rai

    2015-01-01

    To determine whether the predefined calibration factors of the dose calibrators can provide accurate radioactivity measurements of beta-gamma emitters used in routine therapeutic nuclear medicine procedures. Two models of dose calibrators were used in the present study for radioactivity measurements of 153 Sm ethylenediamine-N, N, N’, N’-tetrakis methylene phosphonic acid (EDTMP) and 177 Lu (EDTMP). A known (precalibrated) activity of each of the two beta emitters received by us from our National Supplier for administration to the patients with extensive bony metastases for bone pain palliation, was used for experiments. When we used the manufacturers’ provided dial setting of 450 × 10, each of the dose calibrators underestimated the radioactivity of 177 Lu by about 9.0%. Dial settings of 403 × 10 and 408 × 10 for 177 Lu on CRC-15R and CRC-ultra dose calibrators respectively were calculated experimentally using an iterative approach. The radioactivity measurements made at these settings provided an excellent agreement with the specified values. Likewise, a dial setting of 230 for each of the two dose calibrators was calculated for 153 Sm, which provided a good agreement between the experimentally derived radioactivity values and the certified values. A deviation of ± 5.0% was observed when radioactivity of 177 Lu and 153 Sm was measured over a wide range (4.0 MBq to 2.1 GBq) for time intervals equivalent to 4.5 half-lives of each of the two radionuclides. A deviation of ± 5% was observed when radioactivity was counted in different dilution volumes and in syringes of varying size. These variations could lead to a cumulative error of about 20.0% toward the inaccuracy in the radioactivity measurements of the beta-gamma emitters and thus predefined calibration factors of the dose calibrators may require experimental re-setting of these parameters and periodic checking to provide accurate radioactivity estimates of beta-gamma emitters in a given clinical

  3. Measurement and simulation of the TRR BNCT beam parameters

    Energy Technology Data Exchange (ETDEWEB)

    Bavarnegin, Elham [Nuclear Science and Technology Research Institute (NSTRI), Tehran (Iran, Islamic Republic of); Department of Physics, University of Guilan, Rasht (Iran, Islamic Republic of); Sadremomtaz, Alireza [Department of Physics, University of Guilan, Rasht (Iran, Islamic Republic of); Khalafi, Hossein [Nuclear Science and Technology Research Institute (NSTRI), Tehran (Iran, Islamic Republic of); Kasesaz, Yaser, E-mail: ykasesaz@aeoi.org.ir [Nuclear Science and Technology Research Institute (NSTRI), Tehran (Iran, Islamic Republic of); Golshanian, Mohadeseh; Ghods, Hossein; Ezzati, Arsalan; Keyvani, Mehdi; Haddadi, Mohammad [Nuclear Science and Technology Research Institute (NSTRI), Tehran (Iran, Islamic Republic of)

    2016-09-11

    Recently, the configuration of the Tehran Research Reactor (TRR) thermal column has been modified and a proper thermal neutron beam for preclinical Boron Neutron Capture Therapy (BNCT) has been obtained. In this study, simulations and experimental measurements have been carried out to identify the BNCT beam parameters including the beam uniformity, the distribution of the thermal neutron dose, boron dose, gamma dose in a phantom and also the Therapeutic Gain (TG). To do this, the entire TRR structure including the reactor core, pool, the thermal column and beam tubes have been modeled using MCNPX Monte Carlo code. To measure in-phantom dose distribution a special head phantom has been constructed and foil activation techniques and TLD700 dosimeter have been used. The results show that there is enough uniformity in TRR thermal BNCT beam. TG parameter has the maximum value of 5.7 at the depth of 1 cm from the surface of the phantom, confirming that TRR thermal neutron beam has potential for being used in treatment of superficial brain tumors. For the purpose of a clinical trial, more modifications need to be done at the reactor, as, for example design, and construction of a treatment room at the beam exit which is our plan for future. To date, this beam is usable for biological studies and animal trials. There is a relatively good agreement between simulation and measurement especially within a diameter of 10 cm which is the dimension of usual BNCT beam ports. This relatively good agreement enables a more precise prediction of the irradiation conditions needed for future experiments.

  4. Beam brilliance investigation of high current ion beams at GSI heavy ion accelerator facility.

    Science.gov (United States)

    Adonin, A A; Hollinger, R

    2014-02-01

    In this work the emittance measurements of high current Ta-beam provided by VARIS (Vacuum Arc Ion Source) ion source are presented. Beam brilliance as a function of beam aperture at various extraction conditions is investigated. Influence of electrostatic ion beam compression in post acceleration gap on the beam quality is discussed. Use of different extraction systems (single aperture, 7 holes, and 13 holes) in order to achieve more peaked beam core is considered. The possible ways to increase the beam brilliance are discussed.

  5. Obtaining the Bunch Shape in a Linac from Beam Spectrum Measurements

    International Nuclear Information System (INIS)

    Bane, Karl LF

    1999-01-01

    In linacs with high single-bunch charge, and tight tolerances for energy spread and emittance growth, controlling the short-range wakefield effects becomes extremely important. The effects of the wakefields, in turn, depend on the bunch length and also on the bunch shape. It was shown in the linac of the Stanford Linear Collider (SLC), for example, that by shaping the bunch, the final rms energy spread could be greatly reduced, compared to for the standard Gaussian bunch shape[1]. Therefore, in machines with high single-bunch charge, a method of measuring bunch shape can be an important beam diagnostic. In a linac with low single-bunch charge, the longitudinal bunch shape can be obtained relatively easily from a single measurement of the beam's final energy spectrum, provided that the final to initial energy ratio is large. One merely shifts the average phase of the beam, so that it rides off-crest sufficiently to induce an energy variation that is monotonic with longitudinal position. Then, by knowing the initial and final energies, the rf wave number, and the average beam phase, one can directly map the spectrum into the bunch shape. In a linac with high single-bunch charge, however, due to the effect of the longitudinal wakefield, this method either does not work at all, or it requires such a large shift in beam phase as to become impractical. In earlier work[2],[3] it was shown that, even when wakefields are important, if one measures the final beam spectrum for two different (properly chosen) values of beam phase, then one can again obtain the bunch shape, and--as a by-product--also the form of the wakefield induced voltage; this method was then illustrated using data from the linac of the SLC. These SLC measurements, however, had been performed with the machine in a special configuration, where the current was low; in addition, the noise the data was low and the measured spectra were smooth distributions. Under normal SLC conditions, however, the currents

  6. Beam tomography or ART in accelerator physics

    International Nuclear Information System (INIS)

    Fraser, J.S.

    1978-11-01

    Projections of charged particle beam current density have been used for many years as a measure of beam position and size. The conventional practice of obtaining only two projections, usually in the horizontal and vertical planes, puts a severe limit on the detail that can be recovered from the projections. A third projection provides sufficient improvement to justify the addition of a wire to the conventional wire scanner in certain cases. A group of programs using algebraic reconstruction techniques was written to reconstruct beam current density from beam projections obtained at three or more specific or arbitrary angles around the beam. A generalized program, which makes use of arbitrary 2 x 2 transfer matrices between projections, can be used to reconstruct transverse or longitudinal emittance from appropriate projections. Reconstruction examples of beam current density and transverse and longitudinal emittance using experimental data from the Clinton P. Anderson Meson Physics Facility (LAMPF) accelerator beam are given

  7. Precision measurements of the SLC [Stanford Linear Collider] beam energy

    International Nuclear Information System (INIS)

    Kent, J.; King, M.; Von Zanthier, C.

    1989-03-01

    A method of precisely determining the beam energy in high energy linear colliders has been developed using dipole spectrometers and synchrotron radiation detectors. Beam lines implementing this method have been installed on the Stanford Linear Collider. An absolute energy measurement with an accuracy of better than δE/E = 5 /times/ 10/sup /minus/4/ can be achieved on a pulse-to-pulse basis. The operation of this system will be described. 4 refs., 3 figs., 1 tab

  8. Characterisation of electron beams from laser-driven particle accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Brunetti, E.; Manahan, G. G.; Shanks, R. P.; Islam, M. R.; Ersfeld, B.; Anania, M. P.; Cipiccia, S.; Issac, R. C.; Vieux, G.; Welsh, G. H.; Wiggins, S. M.; Jaroszynski, D. A. [Physics Department, University of Strathclyde, Glasgow G4 0NG (United Kingdom)

    2012-12-21

    The development, understanding and application of laser-driven particle accelerators require accurate measurements of the beam properties, in particular emittance, energy spread and bunch length. Here we report measurements and simulations showing that laser wakefield accelerators can produce beams of quality comparable to conventional linear accelerators.

  9. Beam distribution function after filamentation

    Energy Technology Data Exchange (ETDEWEB)

    Raubenheimer, T.O.; Decker, F.J.; Seeman, J.T.

    1995-05-01

    In this paper, the authors calculate the beam distribution function after filamentation (phase-mixing) of a focusing mismatch. This distribution is relevant when interpreting beam measurements and sources of emittance dilution in linear colliders. It is also important when considering methods of diluting the phase space density, which may be required for the machine protection system in future linear colliders, and it is important when studying effects of trapped ions which filament in the electron beam potential. Finally, the resulting distribution is compared with measured beam distributions from the SLAC linac.

  10. Correction of beam-beam effects in luminosity measurement in the forward region at CLIC

    CERN Document Server

    Lukic, Strahinja

    2013-01-01

    Procedures for correcting the beam-beam effects in luminosity measurement at CLIC at 3 TeV CM energy are described and tested using Monte Carlo simulations: -> Correction of the angular counting loss due to the combined Beamstrahlung and initial-state radiation (ISR) effects, based on the reconstructed velocity of the collision frame of the Bhabha scattering. -> Deconvolution of the luminosity spectrum distortion due to the ISR emission. -> Correction of the counting bias due to the finite calorimeter energy resolution. All procedures were tested by simulation. Bhabha events were generated using BHLUMI, and used in Guinea-PIG to simulate the outgoing momenta of Bhabha particles in the bunch collisions at CLIC. Residual uncertainties after correction are listed in a table in the conclusions. The beam-beam related systematic counting uncertainty in the luminosity peak can be reduced to the order of permille.

  11. Correction of beam-beam effects in luminosity measurement in the forward region at CLIC

    CERN Document Server

    Lukic, Strahinja

    2013-01-01

    Procedures for correcting the beam-beam effects in luminosity measurement at CLIC at 3 TeV CM energy are described and tested using Monte Carlo simulations: - Correction of the angular counting loss due to the combined Beamstrahlung and initial-state radiation (ISR) effects, based on the reconstructed velocity of the collision frame of the Bhabha scattering. - Deconvolution of the luminosity spectrum distortion due to the ISR emission. - Correction of the counting bias due to the finite calorimeter energy resolution. All procedures were tested by simulation. Bhabha events were generated using BHLUMI, and used in Guinea-PIG to simulate the outgoing momenta of Bhabha particles in the bunch collisions at CLIC. Residual uncertainties after correction are listed in a table in the conclusions. The beam-beam related systematic counting uncertainty in the luminosity peak can be reduced to the order of permille.

  12. Precision luminosity measurement at LHCb with beam-gas imaging

    CERN Document Server

    Barschel, Colin

    The luminosity is the physical quantity which relates the cross-section to the production rate in collider experiments. The cross-section being the particle physics observable of interest, a precise determination of the luminosity is required. This work presents the absolute luminosity calibration results performed at the Large Hadron Collider beauty (LHCb) experiment at CERN using a novel method based on beam-gas interactions with data acquired at a center of mass energy $\\sqrt{s}=8$ TeV and $\\sqrt{s}=2.76$ TeV. Reconstructed beam-gas interaction vertices in LHCb are used to measure the beam profiles, thus making it possible to determine the beams overlap integral. An important element of this work was to install and use a neon gas injection system to increase the beam-gas interaction rate. The precision reached with the beam-gas imaging method relies on the two-dimensional beam shape determination developed in this work. For such precision, the interaction vertex resolution is an important ingredient. There...

  13. Study of the many-dimensional transverse phase-space distributions of intense ion beams

    International Nuclear Information System (INIS)

    Riehl, G.

    1993-12-01

    Aim of this thesis was the study of the transverse phase-space distributions of intense ion beams and especially the determination of the emittance growth and the filaments of the distributions. Developed was a facility, which determines under application of each two perpendicularly arranged slit apertures and profile grids and a multichannel current-amplifier plug-in both beam profile and beam emittance of the two transverse motion planes. After the determination of the 1- and 2-dimensional phase-space distributions was successfully realized, the facility was further developed for the measurement of the 3-dimensional phase-space distributions. The observed growth of the emittance and RMS growth on magnetic solenoids could be quantitatively determined and their different causes determined. The growth factors of an optically only slightly filamented beam emittance between 1.5 and 3.2 show that the beam quality is strongly interfered by such influences. The measurements showed beyond the causes and the connection between the filamentation of the emittance as well as the origin of the hollow beams and beam halos observed in many experiments. It could be shown that not only magnetic fields and space-charge fields but pricipally each radial-symmetric, nonlinear field couples the two transverse motion planes and by this causes in nearly all cases a growth of the beam emittance

  14. Experimental results of the laserwire emittance scanner for LINAC4 at CERN

    Energy Technology Data Exchange (ETDEWEB)

    Hofmann, Thomas, E-mail: thomas.hofmann@cern.ch [CERN, Geneva 1211 (Switzerland); John Adams Institute at Royal Holloway, University of London, Egham TW20 0EX (United Kingdom); Friedrich-Alexander-University, Erlangen 91054 (Germany); Boorman, Gary E.; Bosco, Alessio [John Adams Institute at Royal Holloway, University of London, Egham TW20 0EX (United Kingdom); Bravin, Enrico [CERN, Geneva 1211 (Switzerland); Gibson, Stephen M.; Kruchinin, Konstantin O. [John Adams Institute at Royal Holloway, University of London, Egham TW20 0EX (United Kingdom); Raich, Uli; Roncarolo, Federico; Zocca, Francesca [CERN, Geneva 1211 (Switzerland)

    2016-09-11

    Within the framework of the LHC Injector Upgrade (LIU), the new LINAC4 is currently being commissioned to replace the existing LINAC2 proton source at CERN. After the expected completion at the end of 2016, the LINAC4 will accelerate H{sup −} ions to 160 MeV. To measure the transverse emittance of the H{sup −} beam, a method based on photo-detachment is proposed. This system will operate using a pulsed laser with light delivered via an optical fibre and subsequently focused onto the H{sup −} beam. The laser photons have sufficient energy to detach the outer electron and create H{sup 0}/e{sup −} pairs. In a downstream dipole, the created H{sup 0} particles are separated from the unstripped H{sup −} ions and their distribution is measured with a dedicated detector. By scanning the focused laser beam across the H{sup −} beam, the transverse emittance of the H{sup −} beam can be reconstructed. This paper will first discuss the concept, design and simulations of the laser emittance scanner and then present results from a prototype system used during the 12 MeV commissioning of the LINAC4.

  15. Operational Performance of LCLS Beam Instrumentation

    International Nuclear Information System (INIS)

    Loos, Henrik; Akre, R.; Brachmann, A.; Coffee, R.; Decker, F.-J.; Ding, Y.; Dowell, D.; Edstrom, S.; Emma, P.; Fisher, A.; Frisch, J.; Gilevich, S.; Hays, G.; Hering, Ph.; Huang, Z.; Iverson, R.; Messerschmidt, M.; Miahnahri, A.; Moeller, S.; Nuhn, H.-D.; Ratner, D.

    2010-01-01

    The Linac Coherent Light Source (LCLS) X-ray FEL utilizing the last km of the SLAC linac has been operational since April 2009 and finished its first successful user run last December. The various diagnostics for electron beam properties including beam position monitors, wire scanners, beam profile monitors, and bunch length diagnostics are presented as well as diagnostics for the X-ray beam. The low emittance and ultra-short electron beam required for X-ray FEL operation has implications on the transverse and longitudinal diagnostics. The coherence effects of the beam profile monitors and the challenges of measuring fs long bunches are discussed.

  16. Operational Performance of LCLS Beam Instrumentation

    Energy Technology Data Exchange (ETDEWEB)

    Loos, Henrik; Akre, R.; Brachmann, A.; Coffee, R.; Decker, F.-J.; Ding, Y.; Dowell, D.; Edstrom, S.; Emma, P.; Fisher, A.; Frisch, J.; Gilevich, S.; Hays, G.; Hering, Ph.; Huang, Z.; Iverson, R.; Messerschmidt, M.; Miahnahri, A.; Moeller, S.; Nuhn, H.-D.; Ratner, D.; /SLAC /LLNL, Livermore

    2010-06-15

    The Linac Coherent Light Source (LCLS) X-ray FEL utilizing the last km of the SLAC linac has been operational since April 2009 and finished its first successful user run last December. The various diagnostics for electron beam properties including beam position monitors, wire scanners, beam profile monitors, and bunch length diagnostics are presented as well as diagnostics for the X-ray beam. The low emittance and ultra-short electron beam required for X-ray FEL operation has implications on the transverse and longitudinal diagnostics. The coherence effects of the beam profile monitors and the challenges of measuring fs long bunches are discussed.

  17. Modular low-voltage electron emitters

    International Nuclear Information System (INIS)

    Berejka, Anthony J.

    2005-01-01

    Modular, low-voltage electron emitters simplify electron beam (EB) technology for many industrial uses and for research and development. Modular electron emitters are produced in quantity as sealed systems that are evacuated at the factory, eliminating the need for vacuum pumps at the point of use. A plug-out-plug-in method of replacement facilitates servicing. By using an ultra-thin 6-7 μm titanium foil window, solid-state power supplies, an innovative design to extract and spread the beam (enabling systems to be placed adjacent to each other to extend beam width) and touch-screen computer controls, these modular units combine ease of use and electrical transfer efficiency at voltages that can be varied between 80 kV and 150 kV with beam currents up to 40 mA per 25 cm across the beam window. These new devices have been made in three widths: 5 cm, 25 cm, and 40 cm. Details of the beam construction and illustrations of industrial uses will be presented. Traditional uses in the graphic arts and coatings areas have welcomed this modular technology as well as uses for surface sterilization. Being compact and lightweight (∼15 kg/emitter), these modular beams have been configured around complex shapes to achieve three-dimensional surface curing at high production rates

  18. Modular low-voltage electron emitters

    Science.gov (United States)

    Berejka, Anthony J.

    2005-12-01

    Modular, low-voltage electron emitters simplify electron beam (EB) technology for many industrial uses and for research and development. Modular electron emitters are produced in quantity as sealed systems that are evacuated at the factory, eliminating the need for vacuum pumps at the point of use. A plug-out-plug-in method of replacement facilitates servicing. By using an ultra-thin 6-7 μm titanium foil window, solid-state power supplies, an innovative design to extract and spread the beam (enabling systems to be placed adjacent to each other to extend beam width) and touch-screen computer controls, these modular units combine ease of use and electrical transfer efficiency at voltages that can be varied between 80 kV and 150 kV with beam currents up to 40 mA per 25 cm across the beam window. These new devices have been made in three widths: 5 cm, 25 cm, and 40 cm. Details of the beam construction and illustrations of industrial uses will be presented. Traditional uses in the graphic arts and coatings areas have welcomed this modular technology as well as uses for surface sterilization. Being compact and lightweight (∼15 kg/emitter), these modular beams have been configured around complex shapes to achieve three-dimensional surface curing at high production rates.

  19. Development of diagnostic beams for alpha particle measurement on ITER

    Energy Technology Data Exchange (ETDEWEB)

    Sasao, M.; Taniike, A.; Nomura, I.; Wada, M.; Yamaoka, H.; Sato, M.

    1995-08-01

    The feasibility of alpha particle measurement using a high energy diagnostic beam in combination with a neutral particle analyzer is examined for a burning plasma on ITER. In order to measure them in the energy range of 0.5 - 3.5 MeV, the required beam energy is around 1 MeV for a {sup 3}He{sup 0} beam and 3 MeV for a {sup 6}Li{sup 0} beam with the beam current density of around 1 mA/cm{sup 2} for both cases. Among the various methods to produce such a high energy neutral beam, the acceleration of negative ions is most favorable. Recent results of relatively small-scale experiments on these negative ion sources show that the required current density is now realistic. Some technical problems how to scale-up the ion sources to be used on an ITER-size experiment are also studied on these experiments. (author).

  20. ILC beam energy measurement by means of laser Compton backscattering

    Energy Technology Data Exchange (ETDEWEB)

    Muchnoi, N. [Budker Inst. for Nuclear Physics, Novosibirsk (Russian Federation); Schreiber, H.J.; Viti, M. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany)

    2008-10-15

    A novel, non-invasive method of measuring the beam energy at the International Linear Collider is proposed. Laser light collides head-on with beam particles and either the energy of the Compton scattered electrons near the kinematic end-point is measured or the positions of the Compton backscattered {gamma}-rays, the edge electrons and the unscattered beam particles are recorded. A compact layout for the Compton spectrometer is suggested. It consists of a bending magnet and position sensitive detectors operating in a large radiation environment. Several options for high spatial resolution detectors are discussed. Simulation studies support the use of an infrared or green laser and quartz fiber detectors to monitor the backscattered photons and edge electrons. Employing a cavity monitor, the beam particle position downstream of the magnet can be recorded with submicrometer precision. Such a scheme provides a feasible and promising method to access the incident beam energy with precisions of 10{sup -4} or better on a bunch-to-bunch basis while the electron and positron beams are in collision. (orig.)

  1. Antiproton beam profile measurements using Gas Electron Multipliers

    CERN Document Server

    Duarte Pinto, Serge; Spanggaard, Jens; Tranquille, Gerard

    2011-01-01

    The new beam profile measurement for the Antiproton Decelerator (AD) at CERN is based on a single Gas Electron Multiplier (GEM) with a 2D readout structure. This detector is very light, ~0.4% X_0, as required by the low energy of the antiprotons, 5.3 MeV. This overcomes the problems previously encountered with multi-wire proportional chambers (MWPC) for the same purpose, where beam interactions with the detector severely affect the obtained profiles. A prototype was installed and successfully tested in late 2010, with another five detectors now installed in the ASACUSA and AEgIS beam lines. We will provide a detailed description of the detector and discuss the results obtained. The success of these detectors in the AD makes GEM-based detectors likely candidates for upgrade of the beam profile monitors in all experimental areas at CERN. The various types of MWPC currently in use are aging and becoming increasingly difficult to maintain.

  2. A SIMPLE METHOD FOR MEASURING THE ELECTRON-BEAM MAGNETIZATION

    Energy Technology Data Exchange (ETDEWEB)

    Halavanau, A. [Fermilab; Qiang, G. [Tsinghua U., Beijing, Dept. Eng. Phys.; Wisniewski, E. [Argonne; Ha, G. [POSTECH, Pohang; Power, J. [Argonne; Piot, P. [Fermilab

    2016-10-18

    There are a number of projects that require magnetized beams, such as electron cooling or aiding in “flat” beam transforms. Here we explore a simple technique to characterize the magnetization, observed through the angular momentum of magnetized beams. These beams are produced through photoemission. The generating drive laser first passes through microlens arrays (fly-eye light condensers) to form a transversely modulated pulse incident on the photocathode surface [1]. The resulting charge distribution is then accelerated from the photocathode. We explore the evolution of the pattern via the relative shearing of the beamlets, providing information about the angular momentum. This method is illustrated through numerical simulations and preliminary measurements carried out at the Argonne Wakefield Accelerator (AWA) facility are presented.

  3. First Beam Measurements with the LHC Synchrotron Light Monitors

    CERN Document Server

    Bravin, E; Fisher, AS; Guerrero, A; Jeff, A; Lefevre, T; Goldblatt, A; Roncarolo, F

    2010-01-01

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

  4. MD 979: Beta-beating measurements on colliding beams

    CERN Document Server

    Goncalves Jorge, Patrik; Pieloni, Tatiana; Buffat, Xavier; Carlier, Felix Simon; Coello De Portugal - Martinez Vazquez, Jaime Maria; Fol, Elena; Langner, Andy Sven; Medina Medrano, Luis Eduardo; Olexa, Jakub; Tomas Garcia, Rogelio; Valuch, Daniel; Wegscheider, Andreas; CERN. Geneva. ATS Department

    2017-01-01

    The HL-LHC high brightness beams will give a large β-beating due to the head-on and long-range interactions since a beam-beam parameter of 0.01 per Interaction Point (IP) is expected. The β-heating induced by two head-on collision reaches 15%. A third IP, i.e. IP8, could bring the β-heating up to 24%. The aim of the Machine Development (MD) study was to test optics measurements with AC dipole and ADT on colliding beams at injection and to implement a correction of the β-heating due to to head-on collision in the two experiments IP1&5. Int his note, we summarize the first results of this test performed in the LHC.

  5. Measurement of guided mode wave vectors by analysis of the transfer matrix obtained with multi-emitters and multi-receivers in contact

    Energy Technology Data Exchange (ETDEWEB)

    Minonzio, Jean-Gabriel; Talmant, Maryline; Laugier, Pascal, E-mail: jean-gabriel.minonzio@upmc.fr [UPMC Univ Paris 06, UMR 7623, LIP, 15 rue de l' ecole de medecine F-75005, Paris (France)

    2011-01-01

    Different quantitative ultrasound techniques are currently developed for clinical assessment of human bone status. This paper is dedicated to axial transmission: emitters and receivers are linearly arranged on the same side of the skeletal site, preferentially the forearm. In several clinical studies, the signal velocity of the earliest temporal event has been shown to discriminate osteoporotic patients from healthy subjects. However, a multi parameter approach might be relevant to improve bone diagnosis and this be could be achieved by accurate measurement of guided waves wave vectors. For clinical purposes and easy access to the measurement site, the length probe is limited to about 10 mm. The limited number of acquisition scan points on such a short distance reduces the efficiency of conventional signal processing techniques, such as spatio-temporal Fourier transform. The performance of time-frequency techniques was shown to be moderate in other studies. Thus, optimised signal processing is a critical point for a reliable estimate of guided mode wave vectors. Toward this end, a technique, taking benefit of using both multiple emitters and multiple receivers, is proposed. The guided mode wave vectors are obtained using a projection in the singular vectors basis. Those are determined by the singular values decomposition of the transmission matrix between the two arrays at different frequencies. This technique enables us to recover accurately guided waves wave vectors for moderately large array.

  6. Atomic physics measurements in an electron beam ion trap

    Science.gov (United States)

    Marrs, R. E.; Beiersdorfer, P.; Bennett, C.; Chen, M. H.; Cowan, T.; Dietrich, D.; Henderson, J. R.; Knapp, D. A.; Osterheld, S.; Schneider, M. B.; Scofield, J. H.; Levine, M. A.

    1989-06-01

    An electron Beam Ion Trap at Lawrence Livermore National Laboratory is being used to produce and trap very-highly-charged ions (q≥70+) for x-ray spectroscopy measurements. Recent measurements of transition energies and electron excitation cross sections for x-ray line emission are summarized.

  7. Cherenkov Detector for Beam Quality Measurement

    CERN Document Server

    AUTHOR|(CDS)2078842

    2016-01-01

    A new detector to measure the machine induced background at larger radiihas been developed and installed in the CMS experiment at LHC. Itconsists of 40 modules, each comprising a quartz bar read out by aphotomultiplier. Since Cerenkov radiation is emitted in a forward conearound the charged particle trajectory, these detectors can distinguishthe directions of the machine induced background.The back-end consists of a microTCA readout with excellent time resolution.The performance of the detector modules measured in several test-beamcampaigns will be reported. The installation in CMS will be described, andfirst results about operating the detector during data taking will begiven.

  8. Polystyrene calorimeter for electron beam dose measurements

    DEFF Research Database (Denmark)

    Miller, A.

    1995-01-01

    Calorimeters from polystrene have been constructed for dose measurement at 4-10 MeV electron accelerators. These calorimeters have been used successfully for a few years, and polystyrene calorimeters for use at energies down to 1 MeV and being tested. Advantage of polystyrene as the absorbing...

  9. Absolute luminosity measurement at LHCb with beam-gas imaging

    CERN Document Server

    Barschel, C

    2013-01-01

    A novel technique to measure the absolute luminosity at the Large Hadron Collider (LHC) using beam-gas interactions has been successfully used in the LHCb experiment. A gas injection device (SMOG) has been installed in the LHCb experiment to increase the pressure around the interaction point during dedicated fills. The Beam-Gas Imaging method (BGI) has now the potential to surpass the accuracy of the commonly used *van der Meer scan* method (VDM). The technique has been used in 10 LHC fills during 2012 including and also provided a first luminosity measurement for proton-lead collisions. This talk presents the principles of the gas injection and the improvements reached with the increased pressure. Furthermore the gas injection increased the accuracy measurement of the so-called ghost charges and also intensities per bunch. Those uncertainties are becoming the dominating factor because the uncertainty on the total beam current have been reduced.

  10. Observations and diagnostics in high brightness beams

    Energy Technology Data Exchange (ETDEWEB)

    Cianchi, A., E-mail: alessandro.cianchi@roma2.infn.it [University of Rome Tor Vergata and INFN-Roma Tor Vergata, Via della Ricerca Scientifica 1, 00133 Rome (Italy); Anania, M.P.; Bisesto, F.; Castellano, M.; Chiadroni, E.; Pompili, R.; Shpakov, V. [INFN-LNF, Via Enrico Fermi 40, 00044 Frascati (Italy)

    2016-09-01

    The brightness is a figure of merit largely used in the light sources, like FEL (Free Electron Lasers), but it is also fundamental in several other applications, as for instance Compton backscattering sources, beam driven plasma accelerators and THz sources. Advanced diagnostics are essential tools in the development of high brightness beams. 6D electron beam diagnostics will be reviewed with emphasis on emittance measurement.

  11. Proportional counter measurements in neutron therapy beams

    International Nuclear Information System (INIS)

    Menzel, H.G.

    1984-01-01

    Dosimetry for clinical neutron therapy requires a characterization of radiation quality in addition to the specification of absorbed dose. Generally, a very simple approach has been adopted which consists in separating total absorbed dose into neutron and photon fractions. This is explained by the requirement of clinical dosimetry to apply methods suitable for routine measurements, by the lack of generally accepted improved alternatives, and by the fact that radiation quality is only one of several problems in neutron therapy not sufficiently solved. Spectra measured with low-pressure tissue-equivalent proportional counters (experimental microdosimetry) provide a detailed description of the physical properties of the radiation field at neutron therapy facilities. These descriptions are suitable for explaining the influence of different parameters (collimation, field size, phantom) on radiation quality. Although the physical properties of the radiation field as described by the measured microdosimetric distributions and quantities are not the only properties relevant for radiation effects, in general there are reasons to believe that they provide a suitable radiation quality characterization for the limited range of applications in neutron therapy. (author)

  12. The emittances and brightnesses of high-intensity negative ion sources

    International Nuclear Information System (INIS)

    Alton, G.D.; McConnell, J.W.

    1987-01-01

    The emittances of high-intensity ion beams extracted from cesium sputter negative ion sources equipped with cylindrical and ellipsoidal solid tungsten and spiral-wound tantalum (General Ionex Corporation, Model 860), and cesium surface ionizers have been measured for several ion species, including 12 C - , 28 Si - , 58 Ni - , and 197 Au - . While certain sets of data from the ellipsoidal and cylindrical geometry ionizer sources suggest a moderate growth in emittance with increasing negative ion beam intensity I over the range of intensities investigated (5 ≤ 1 ≤ 60 μA) of perhaps 20%, not all data exhibit this dependence, especially those from the Model 860 source. As well, no evidence of an emittance dependence on ion mass of a monotonic nature was found. The emittances of ion beams at the 80% intensity level from the Model 860 source are found to be higher on the average by factors of 1.8 and 1.7, respectively, than those from sources equipped with ellipsoidal and cylindrical geometry cesium surface ionizers

  13. Half-life, branching-ratio, and Q-value measurement for the superallowed 0+→0+β+ emitter 42Ti

    International Nuclear Information System (INIS)

    Nieto, T. Kurtukian; Souin, J.; Audirac, L.; Blank, B.; Giovinazzo, J.; Eronen, T.; Aeystoe, J.; Elomaa, V.-V.; Hager, U.; Hakala, J.; Jokinen, A.; Kankainen, A.; Karvonen, P.; Kessler, T.; Moore, I. D.; Penttilae, H.; Rahaman, S.; Reponen, M.; Rissanen, J.; Saastamoinen, A.

    2009-01-01

    The half-life, the branching ratio, and the decay Q value of the superallowed β emitter 42 Ti were measured in an experiment performed at the JYFLTRAP facility of the Accelerator Laboratory of the University of Jyvaeskylae. 42 Ti is the heaviest T z =-1 nucleus for which high-precision measurements of these quantities have been tried. The half-life (T 1/2 =208.14±0.45 ms) and the Q value [Q EC =7016.83(25) keV] are close to or reach the required precision of about 0.1%. The branching ratio for the superallowed decay branch [BR=47.7(12)%], a by-product of the half-life measurement, does not reach the necessary precision yet. Nonetheless, these results allow one to determine the experimental ft value and the corrected Ft value to be 3114(79) and 3122(79) s, respectively.

  14. Electron beam water calorimetry measurements to obtain beam quality conversion factors.

    Science.gov (United States)

    Muir, Bryan R; Cojocaru, Claudiu D; McEwen, Malcolm R; Ross, Carl K

    2017-10-01

    To provide results of water calorimetry and ion chamber measurements in high-energy electron beams carried out at the National Research Council Canada (NRC). There are three main aspects to this work: (a) investigation of the behavior of ionization chambers in electron beams of different energies with focus on long-term stability, (b) water calorimetry measurements to determine absorbed dose to water in high-energy beams for direct calibration of ion chambers, and (c) using measurements of chamber response relative to reference ion chambers, determination of beam quality conversion factors, k Q , for several ion chamber types. Measurements are made in electron beams with energies between 8 MeV and 22 MeV from the NRC Elekta Precise clinical linear accelerator. Ion chamber measurements are made as a function of depth for cylindrical and plane-parallel ion chambers over a period of five years to investigate the stability of ion chamber response and for indirect calibration. Water calorimetry measurements are made in 18 MeV and 22 MeV beams. An insulated enclosure with fine temperature control is used to maintain a constant temperature (drifts less than 0.1 mK/min) of the calorimeter phantom at 4°C to minimize effects from convection. Two vessels of different designs are used with calibrated thermistor probes to measure radiation induced temperature rise. The vessels are filled with high-purity water and saturated with H 2 or N 2 gas to minimize the effect of radiochemical reactions on the measured temperature rise. A set of secondary standard ion chambers are calibrated directly against the calorimeter. Finally, several other ion chambers are calibrated in the NRC 60 Co reference field and then cross-calibrated against the secondary standard chambers in electron beams to realize k Q factors. The long-term stability of the cylindrical ion chambers in electron beams is better (always <0.15%) than plane-parallel chambers (0.2% to 0.4%). Calorimetry measurements

  15. Recent beam probe measurements on EBT, TMX, and RENTOR

    Energy Technology Data Exchange (ETDEWEB)

    Hickok, R L

    1980-06-01

    It is noted that beam probe systems can provide accurate, reliable measurments of plasma space potential and nf(T/sub e/). Over some temperature range, at least, it should be possible to separate n and T/sub e/ by measuring the multiple ionization reaction products. It is also an ideal diagnostic for studying fluctuations since it provides a simultaneous measurement of phi and nf(T/sub e/) from the same point in the plasma and the measurements are continuous in time. Measurements can be made quasi-continuously in space by rapidly sweeping the beam. By using more than one detector it should be possible to make measurements simultaneously at two different observation points in the plasma.

  16. Recent beam probe measurements on EBT, TMX, and RENTOR

    International Nuclear Information System (INIS)

    Hickok, R.L.

    1980-06-01

    It is noted that beam probe systems can provide accurate, reliable measurments of plasma space potential and nf(T/sub e/). Over some temperature range, at least, it should be possible to separate n and T/sub e/ by measuring the multiple ionization reaction products. It is also an ideal diagnostic for studying fluctuations since it provides a simultaneous measurement of phi and nf(T/sub e/) from the same point in the plasma and the measurements are continuous in time. Measurements can be made quasi-continuously in space by rapidly sweeping the beam. By using more than one detector it should be possible to make measurements simultaneously at two different observation points in the plasma

  17. Plasma-parameter measurements using neutral-particle-beam attenuation

    International Nuclear Information System (INIS)

    Foote, J.H.; Molvik, A.W.; Turner, W.C.

    1982-01-01

    Intense and energetic neutral-particle-beam injection used for fueling or heating magnetically confined, controlled-fusion experimental plasmas can also provide diagnostic measurements of the plasmas. The attenuation of an atomic beam (mainly from charge-exchange and ionization interactions) when passing through a plasma gives the plasma line density. Orthogonal arrays of highly collimated detectors of the secondary-electron-emission type have been used in magnetic-mirror experiments to measure neutral-beam attenuation along chords through the plasma volume at different radial and axial positions. The radial array is used to infer the radial plasma-density profile; the axial array, to infer the axial plasma-density profile and the ion angular distribution at the plasma midplane

  18. Transverse emittance and phase space program developed for use at the Fermilab A0 Photoinjector

    Energy Technology Data Exchange (ETDEWEB)

    Thurman-Keup, R.; Johnson, A.S.; Lumpkin, A.H.; Ruan, J.; /Fermilab

    2011-03-01

    The Fermilab A0 Photoinjector is a 16 MeV high intensity, high brightness electron linac developed for advanced accelerator R&D. One of the key parameters for the electron beam is the transverse beam emittance. Here we report on a newly developed MATLAB based GUI program used for transverse emittance measurements using the multi-slit technique. This program combines the image acquisition and post-processing tools for determining the transverse phase space parameters with uncertainties. An integral part of accelerator research is a measurement of the beam phase space. Measurements of the transverse phase space can be accomplished by a variety of methods including multiple screens separated by drift spaces, or by sampling phase space via pepper pots or slits. In any case, the measurement of the phase space parameters, in particular the emittance, can be drastically simplified and sped up by automating the measurement in an intuitive fashion utilizing a graphical interface. At the A0 Photoinjector (A0PI), the control system is DOOCS, which originated at DESY. In addition, there is a library for interfacing to MATLAB, a graphically capable numerical analysis package sold by The Mathworks. It is this graphical package which was chosen as the basis for a graphical phase space measurement system due to its combination of analysis and display capabilities.

  19. Transverse emittance and phase space program developed for use at the Fermilab A0 Photoinjector

    International Nuclear Information System (INIS)

    Thurman-Keup, R.; Johnson, A.S.; Lumpkin, A.H.; Ruan, J.

    2011-01-01

    The Fermilab A0 Photoinjector is a 16 MeV high intensity, high brightness electron linac developed for advanced accelerator R and D. One of the key parameters for the electron beam is the transverse beam emittance. Here we report on a newly developed MATLAB based GUI program used for transverse emittance measurements using the multi-slit technique. This program combines the image acquisition and post-processing tools for determining the transverse phase space parameters with uncertainties. An integral part of accelerator research is a measurement of the beam phase space. Measurements of the transverse phase space can be accomplished by a variety of methods including multiple screens separated by drift spaces, or by sampling phase space via pepper pots or slits. In any case, the measurement of the phase space parameters, in particular the emittance, can be drastically simplified and sped up by automating the measurement in an intuitive fashion utilizing a graphical interface. At the A0 Photoinjector (A0PI), the control system is DOOCS, which originated at DESY. In addition, there is a library for interfacing to MATLAB, a graphically capable numerical analysis package sold by The Mathworks. It is this graphical package which was chosen as the basis for a graphical phase space measurement system due to its combination of analysis and display capabilities.

  20. Emittance growth caused by bends in the Los Alamos free-electron laser energy recovery experiment

    International Nuclear Information System (INIS)

    Carlsten, B.E.

    1987-01-01

    Experimentally transporting the beam from the wiggler to the decelerators in the energy recovery experiment (ERX) at the Los Alamos National Laboratory free-electron laser was more difficult than expected because of the large initial emittance in the beam. This emittance was apparently caused in an early 60 0 achromatic bend. To get this beam through subsequent bends without wall interception, the quadrupole focusing had to be changed from the design amount; as a result, the emittance grew further. This paper discusses various mechanisms for this emittance growth in the 60 0 bend, including effects caused by path changes in the bend resulting from wake-field-induced energy changes of particles in the beam and examines emittance filters, ranging from a simple aperture near a beam crossover to more complicated telescope schemes designed to regain the original emittance before the 60 0 bend

  1. Emittance compensation of CW DC-gun photoinjector

    International Nuclear Information System (INIS)

    Li Peng; Wu Dai; Xu Zhou; Li Ming; Yang Xingfan

    2011-01-01

    Emittance growth induced by space charge effect is very important, especially for CW DC-gun photoinjector. In this work, the linear space charge force and its effect on electron beam transverse emittance are studied, and the principle and properties of emittance compensation by solenoid are analyzed. The CAEP DC-gun photoinjector with a solenoid is also simulated by code Parmela. Simulated results indicate that the normalized transverse emittance of an 80 pC bunch at the 350 keV DC-gun ex-it is 5.14 mm · mrad. And after compensated by a solenoid, it becomes 1.27 mm · mrad. The emittance of beam is well compensated. (authors)

  2. Measuring and recording system for electron beam welding parameters

    International Nuclear Information System (INIS)

    Lobanova, N.G.; Lifshits, M.L.; Efimov, I.I.

    1987-01-01

    The observation possibility during electron beam welding of circular articles with guaranteed clearance of welding bath leading front in joint gap and flare cloud over the bath by means of television monitor is considered. The composition and operation mode of television measuring system for metric characteristics of flare cloud and altitude of welding bath leading front in the clearance are described

  3. Crystal Collimation Cleaning Measurements with Proton Beams in LHC

    CERN Document Server

    Rossi, Roberto; Andreassen, Odd Oyvind; Butcher, Mark; Dionisio Barreto, Cristovao Andre; Masi, Alessandro; Mirarchi, Daniele; Montesano, Simone; Lamas Garcia, Inigo; Redaelli, Stefano; Scandale, Walter; Serrano Galvez, Pablo; Rijllart, Adriaan; Valentino, Gianluca; CERN. Geneva. ATS Department

    2016-01-01

    During this MD, performed on July 29th, 2016, bent silicon crystal were tested with proton beams for a possible usage of crystal-assisted collimation. Tests were performed at both injection energy and flat top using horizontal and vertical crystal. Loss maps with crystals at 6.5 TeV were measured.

  4. Measuring and assessing the physical impact of beam trawling

    NARCIS (Netherlands)

    Depestele, J.; Ivanovic, A.; Esmaelli, M.; Polet, H.; Roche, M.; Summerbell, K.; Teal, L.R.; Vanelslander, B.; O'Neill, F.G.

    2016-01-01

    Beam trawling causes physical disruption of the seabed through contact of the gear components with the sediment and the resuspension of sediment into the water column in the turbulent wake of the gear. To be able to measure and quantify these impacts is important so that gears of reduced impact can

  5. Electron density measurements during ion beam transport on Gamble II

    International Nuclear Information System (INIS)

    Weber, B.V.; Hinshelwood, D.D.; Neri, J.M.; Ottinger, P.F.; Rose, D.V.; Stephanakis, S.J.; Young, F.C.

    1999-01-01

    High-sensitivity laser interferometry was used to measure the electron density created when an intense proton beam (100 kA, 1 MeV, 50 ns) from the Gamble II generator was transported through low-pressure gas as part of a project investigating Self-Pinched Transport (SPT) of intense ion beams. This measurement is non-perturbing and sufficiently quantitative to allow benchmarking of codes (particularly IPROP) used to model beam-gas interaction and ion-beam transport. Very high phase sensitivity is required for this measurement. For example, a 100-kA, 1-MeV, 10-cm-radius proton beam with uniform current density has a line-integrated proton density equal to n b L = 3 x 10 13 cm -2 . An equal electron line-density, n e L = n b L, (expected for transport in vacuum) will be detected as a phase shift of the 1.064 microm laser beam of only 0.05degree, or an optical path change of 1.4 x 10 -4 waves (about the size of a hydrogen atom). The time-history of the line-integrated electron density, measured across a diameter of the transport chamber at 43 cm from the input aperture, starts with the proton arrival time and decays differently depending on the gas pressure. The gas conditions included vacuum (10 -4 Torr air), 30 to 220 mTorr He, and 1 Torr air. The measured densities vary by three orders of magnitude, from 10 13 to 10 16 cm -2 for the range of gas pressures investigated. In vacuum, the measured electron densities indicate only co-moving electrons (n e L approximately n b L). In He, when the gas pressure is sufficient for ionization by beam particles and SPT is observed, n e L increases to about 10 n b L. At even higher pressures where electrons contribute to ionization, even higher electron densities are observed with an ionization fraction of about 2%. The diagnostic technique as used on the SPT experiment will be described and a summary of the results will be given. The measurements are in reasonable agreement with theoretical predictions from the IPROP code

  6. Noninterceptive beam energy measurements in line D of the Los Alamos Meson Physics Facility

    International Nuclear Information System (INIS)

    Gilpatrick, J.D.; Carter, H.; Plum, M.; Power, J.F.; Rose, C.R.; Shurter, R.B.

    1995-01-01

    Several members of the Accelerator and Operations Technology (AOT) division beam-diagnostics team performed time-of-flight (TOF) beam-energy measurements in line D of the Los Alamos Meson Physics Facility (LAMPF) using developmental beam time. These measurements provided information for a final design of an on-line beam energy measurement. The following paper discusses these measurements and how they apply to the final beam energy measurement design

  7. Optimizing beam transport in rapidly compressing beams on the neutralized drift compression experiment – II

    Directory of Open Access Journals (Sweden)

    Anton D. Stepanov

    2018-03-01

    Full Text Available The Neutralized Drift Compression Experiment-II (NDCX-II is an induction linac that generates intense pulses of 1.2 MeV helium ions for heating matter to extreme conditions. Here, we present recent results on optimizing beam transport. The NDCX-II beamline includes a 1-m-long drift section downstream of the last transport solenoid, which is filled with charge-neutralizing plasma that enables rapid longitudinal compression of an intense ion beam against space-charge forces. The transport section on NDCX-II consists of 28 solenoids. Finding optimal field settings for a group of solenoids requires knowledge of the envelope parameters of the beam. Imaging the beam on the scintillator gives the radius of the beam, but the envelope angle is not measured directly. We demonstrate how the parameters of the beam envelope (radius, envelop angle, and emittance can be reconstructed from a series of images taken by varying the B-field strengths of a solenoid upstream of the scintillator. We use this technique to evaluate emittance at several points in the NDCX-II beamline and for optimizing the trajectory of the beam at the entry of the plasma-filled drift section. Keywords: Charged-particle beams, Induction accelerators, Beam dynamics, Beam emittance, Ion beam diagnostics, PACS Codes: 41.75.-i, 41.85.Ja, 52.59.Sa, 52.59.Wd, 29.27.Eg

  8. An Observation of a Transverse to Longitudinal Emittance Exchange at the Fermilab A0 Photoinjector

    Energy Technology Data Exchange (ETDEWEB)

    Koeth, Timothy W [State Univ. of New Jersey, New Brunswick, NJ (United States)

    2009-05-01

    An experimental program to perform a proof of principle of transverse to longitudinal emittance exchange (ϵxin ↔ ϵzout and ϵxin ↔ ϵzout) has been developed at the Fermilab A0 Photoinjector. A new beamline, including two magnetic dogleg channels and a TM110 deflecting mode radio frequency cavity, were constructed for the emittance exchange experiment. The first priority was a measurement of the Emittance Exchange beamline transport matrix. The method of difference orbits was used to measure the transport matrix. Through varying individual beam input vector elements, such as xin, x'in, yin, y'in, zin, or δin, and measuring the changes in all of the beam output vector's elements, xout, x'out, yout, y'out, zout, δout, the full 6 x 6 transport matrix was measured. The measured emittance exchange transport matrix was in overall good agreement with our calculated transport matrix. A direct observation of an emittance exchange was performed by measuring the electron beam's characteristics before and after the emittance exchange beamline. Operating with a 14.3 MeV, 250pC electron bunch, ϵzin of 21.1 ± 1.5 mm • mrad was observed to be exchanged with ϵxout of 20.8 ± 2.00 mm • mrad. Diagnostic limitations in the ϵzout measurement did not account for an energy-time correlation, thus potentially returning values larger than the actual longitudinal emittance. The ϵxin of 4.67 ± 0.22 mm • mrad was observed to be exchanged with ϵzout of 7.06 ± 0.43 mm • mrad. The apparent ϵzoutgrowth is consistent with calculated values in which the correlation term is neglected.

  9. Measurements of beam-ion confinement during tangential beam-driven instabilities in PBX [Princeton Beta Experiment

    International Nuclear Information System (INIS)

    Heidbrink, W.W.; Kaita, R.; Takahashi, H.; Gammel, G.; Hammett, G.W.; Kaye, S.

    1987-01-01

    During tangential injection of neutral beams into low density tokamak plasmas with β > 1% in the Princeton Beta Experiment (PBX), instabilities are observed that degrade the confinement of beam ions. Neutron, charge-exchange, and diamagnetic loop measurements are examined in order to identify the mechanism or mechanisms responsible for the beam-ion transport. The data suggest a resonant interaction between the instabilities and the parallel energetic beam ions. Evidence for some nonresonant transport also exists

  10. The software for the CERN LEP beam orbit measurement system

    International Nuclear Information System (INIS)

    Morpurgo, G.

    1992-01-01

    The Beam Orbit Measurement (BOM) system of LEP consists of 504 pickups, distributed all around the accelerator, that are capable of measuring the positions of the two beams. Their activity has to be synchronized, and the data produced by them have to be collected together, for example to form a 'closed orbit measurement' or a 'trajectory measurement'. On the user side, several clients can access simultaneously the results from this instrument. An automatic acquisition mode, and an 'on request' one, can run in parallel. This results in a very flexible and powerful system. The functionality of the BOM system is fully described, as well as the structure of the software processes which constitute the system, and their interconnections. Problems solved during the implementation are emphasized. (author)

  11. Optical beam diagnostics at the Electron Stretcher Accelerator ELSA; Optische Strahldiagnose an der Elektronen-Stretcher-Anlage ELSA

    Energy Technology Data Exchange (ETDEWEB)

    Zander, Sven

    2013-10-15

    At the ELectron Stretcher Accelerator ELSA, a resonant excitation of the horizontal particle oscillations is used to extract the electrons to the experiments. This so-called resonance extraction influences the properties of the extracted beam. The emittance, as a number of the beam quality, was determined by using synchrotron light monitors. To enable broad investigations of the emittance a system of synchrotron light monitors was set up. This system was used to measure the influence of the extraction method on the emittance. Time resolved measurements were conducted to investigate the development of the emittance during an accelerator cycle. To improve the optical beam diagnostics a new beamline to an external laboratory was constructed. There, a new high resolution synchrotron light monitor was commissioned. In addition, a streak camera has been installed to enable longitudinal diagnostics of the beam profiles. First measurements of the longitudinal charge distribution with a time resolution in the range of a few picoseconds were conducted successfully.

  12. Development and Applications of Residual Stress Measurements Using Neutron Beams

    OpenAIRE

    ABRIOLA S. A.; BALAGUROV A.; BASHIR J.; DAS A.; EDWARDS L.; GNAEUPEL-HEROLD T.; GOH B.; IONITA I.; MIKULA P.; OHMS Carsten; PELD N.; SCHNEIDER Rainer; SUTIARSO S.; TOROK G.; VENTER A.

    2012-01-01

    The deep penetration and selective absorption of neutrons make them a powerful tool in nondestructive testing of materials with large samples or objects. Residual stress formed in a material during manufacturing, welding, utilization or repairs can be measured by means of neutron diffraction. In fact, neutron diffraction is the only non-destructive testing method, which can facilitate 3-D mapping of residual stress in a bulk component. Stress measurement using neutron beams is a technique ...

  13. Characterisation of the Muon Beams for the Muon Ionisation Cooling Experiment

    CERN Document Server

    Adams, D.; Alekou, A.; Apollonio, M.; Asfandiyarov, R.; Back, J.; Barber, G.; Barclay, P.; de Bari, A.; Bayes, R.; Bayliss, V.; Bertoni, R.; Blackmore, V.J.; Blondel, A.; Blot, S.; Bogomilov, M.; Bonesini, M.; Booth, C.N.; Bowring, D.; Boyd, S.; Bradshaw, T.W.; Bravar, U.; Bross, A.D.; Capponi, M.; Carlisle, T.; Cecchet, G.; Charnley, G.; Cobb, J.H.; Colling, D.; Collomb, N.; Coney, L.; Cooke, P.; Courthold, M.; Cremaldi, L.M.; DeMello, A.; Dick, A.; Dobbs, A.; Dornan, P.; Fayer, S.; Filthaut, F.; Fish, A.; Fitzpatrick, T.; Fletcher, R.; Forrest, D.; Francis, V.; Freemire, B.; Fry, L.; Gallagher, A.; Gamet, R.; Gourlay, S.; Grant, A.; Graulich, J.S.; Griffiths, S.; Hanlet, P.; Hansen, O.M.; Hanson, G.G.; Harrison, P.; Hart, T.L.; Hartnett, T.; Hayler, T.; Heidt, C.; Hills, M.; Hodgson, P.; Iaciofano, A.; Ishimoto, S.; Kafka, G.; Kaplan, D.M.; Karadzhov, Y.; Kim, Y.K.; Kolev, D.; Kuno, Y.; Kyberd, P.; Lau, W.; Leaver, J.; Leonova, M.; Li, D.; Lintern, A.; Littlefield, M.; Long, K.; Lucchini, G.; Luo, T.; Macwaters, C.; Martlew, B.; Martyniak, J.; Middleton, S.; Moretti, A.; Moss, A.; Muir, A.; Mullacrane, I.; Nebrensky, J.J.; Neuffer, D.; Nichols, A.; Nicholson, R.; Nugent, J.C.; Onel, Y.; Orestano, D.; Overton, E.; Owens, P.; Palladino, V.; Palmer, R.B.; Pasternak, J.; Pastore, F.; Pidcott, C.; Popovic, M.; Preece, R.; Prestemon, S.; Rajaram, D.; Ramberger, S.; Rayner, M.A.; Ricciardi, S.; Richards, A.; Roberts, T.J.; Robinson, M.; Rogers, C.; Ronald, K.; Rubinov, P.; Rucinski, R.; Rusinov, I.; Sakamoto, H.; Sanders, D.A.; Santos, E.; Savidge, T.; Smith, P.J.; Snopok, P.; Soler, F.J.P.; Stanley, T.; Summers, D.J.; Takahashi, M.; Tarrant, J.; Taylor, I.; Tortora, L.; Torun, Y.; Tsenov, R.; Tunnell, C.D.; Vankova, G.; Verguilov, V.; Virostek, S.; Vretenar, M.; Walaron, K.; Watson, S.; White, C.; Whyte, C.G.; Wilson, A.; Wisting, H.; Zisman, M.

    2013-01-01

    A novel single-particle technique to measure emittance has been developed and used to characterise seventeen different muon beams for the Muon Ionisation Cooling Experiment (MICE). The muon beams, whose mean momenta vary from 171 to 281 MeV/c, have emittances of approximately 1.5--2.3 \\pi mm-rad horizontally and 0.6--1.0 \\pi mm-rad vertically, a horizontal dispersion of 90--190 mm and momentum spreads of about 25 MeV/c. There is reasonable agreement between the measured parameters of the beams and the results of simulations. The beams are found to meet the requirements of MICE.

  14. Characterisation of the muon beams for the Muon Ionisation Cooling Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Adams, D.; Barclay, P.; Bayliss, V.; Bradshaw, T.W.; Courthold, M.; Francis, V.; Fry, L.; Hayler, T.; Hills, M.; Lintern, A.; Macwaters, C.; Nichols, A.; Preece, R.; Ricciardi, S.; Rogers, C.; Stanley, T.; Tarrant, J.; Watson, S.; Wilson, A. [Harwell Oxford, STFC Rutherford Appleton Laboratory, Didcot (United Kingdom); Adey, D.; Back, J.; Boyd, S.; Harrison, P.; Pidcott, C.; Taylor, I. [University of Warwick, Department of Physics, Coventry (United Kingdom); Alekou, A.; Apollonio, M.; Barber, G.; Colling, D.; Dobbs, A.; Dornan, P.; Fayer, S.; Fish, A.; Hunt, C.; Leaver, J.; Long, K.; Martyniak, J.; Middleton, S.; Pasternak, J.; Richards, A.; Santos, E.; Savidge, T.; Takahashi, M. [Imperial College London, Department of Physics, Blackett Laboratory, London (United Kingdom); Asfandiyarov, R.; Blondel, A.; Graulich, J.S.; Karadzhov, Y.; Verguilov, V.; Wisting, H. [Universite de Geneve, DPNC, Section de Physique, Geneva (Switzerland); De Bari, A.; Cecchet, G. [Sezione INFN Pavia (Italy); Dipartimento di Fisica Nucleare e Teorica, Pavia (Italy); Bayes, R.; Forrest, D.; Nugent, J.C.; Soler, F.J.P.; Walaron, K. [The University of Glasgow, School of Physics and Astronomy, Glasgow (United Kingdom); Bertoni, R.; Bonesini, M.; Lucchini, G. [Sezione INFN Milano Bicocca (Italy); Dipartimento di Fisica G. Occhialini, Milano (Italy); Blackmore, V.J.; Carlisle, T.; Cobb, J.H.; Lau, W.; Rayner, M.A.; Tunnell, C.D. [University of Oxford, Department of Physics, Oxford (United Kingdom); Blot, S.; Kim, Y.K. [University of Chicago, Enrico Fermi Institute, Chicago, IL (United States); Bogomilov, M.; Kolev, D.; Rusinov, I.; Tsenov, R.; Vankova, G. [St. Kliment Ohridski University of Sofia, Department of Atomic Physics, Sofia (Bulgaria); Booth, C.N.; Hodgson, P.; Nicholson, R.; Overton, E.; Robinson, M.; Smith, P.J. [University of Sheffield, Department of Physics and Astronomy, Sheffield (United Kingdom); Bowring, D.; DeMello, A.; Gourlay, S.; Li, D.; Prestemon, S.; Virostek, S.P.; Zisman, M.S. [Lawrence Berkeley National Laboratory, Berkeley, CA (United States); Bravar, U. [University of New Hampshire, Durham, NH (United States); Bross, A.D.; Fitzpatrick, T.; Leonova, M.; Moretti, A.; Neuffer, D.; Popovic, M.; Rubinov, P.; Rucinski, R. [Fermilab, Batavia, IL (United States); Capponi, M.; Iaciofano, A.; Orestano, D.; Pastore, F.; Tortora, L. [Sezione INFN Roma Tre e Dipartimento di Fisica, Roma (Italy); Charnley, G.; Collomb, N.; Gallagher, A.; Grant, A.; Griffiths, S.; Hartnett, T.; Martlew, B.; Moss, A.; Muir, A.; Mullacrane, I.; Owens, P.; White, C. [STFC Daresbury Laboratory, Cheshire (United Kingdom); Coney, L.; Fletcher, R.; Hanson, G.G.; Heidt, C. [University of California, Riverside, CA (United States); Cooke, P.; Gamet, R. [University of Liverpool, Department of Physics, Liverpool (United Kingdom); Cremaldi, L.M.; Hart, T.L.; Luo, T.; Sanders, D.A.; Summers, D.J. [University of Mississippi, Oxford, MS (United States); Dick, A.J.; Ronald, K.; Whyte, C.G. [University of Strathclyde, Department of Physics, Glasgow (United Kingdom); Filthaut, F. [NIKHEF, Amsterdam (Netherlands); Freemire, B.; Hanlet, P.; Kafka, G.; Kaplan, D.M.; Rajaram, D.; Snopok, P.; Torun, Y. [Illinois Institute of Technology, Chicago, IL (United States); Hansen, O.M.; Ramberger, S.; Vretenar, M. [CERN, Geneva (Switzerland); Ishimoto, S. [Institute of Particle and Nuclear Studies, High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki (Japan); Kuno, Y.; Sakamoto, H. [Osaka University, Graduate School of Science, Department of Physics, Toyonaka, Osaka (Japan); Kyberd, P.; Littlefield, M.; Nebrensky, J.J. [Brunel University, Uxbridge (United Kingdom); Onel, Y. [University of Iowa, Department of Physics and Astronomy, Iowa City, IA (United States); Palladino, V. [Universita Federico II, Sezione INFN Napoli (Italy); Dipartimento di Fisica, Napoli (Italy); Palmer, R.B. [Brookhaven National Laboratory, Upton, NY (US); Roberts, T.J. [Muons, Inc., Batavia, IL (US); Collaboration: The MICE Collaboration

    2013-10-15

    A novel single-particle technique to measure emittance has been developed and used to characterise seventeen different muon beams for the Muon Ionisation Cooling Experiment (MICE). The muon beams, whose mean momenta vary from 171 to 281 MeV/c, have emittances of approximately 1.2-2.3 {pi} mm-rad horizontally and 0.6-1.0 {pi} mm-rad vertically, a horizontal dispersion of 90-190 mm and momentum spreads of about 25 MeV/c. There is reasonable agreement between the measured parameters of the beams and the results of simulations. The beams are found to meet the requirements of MICE. (orig.)

  15. Characterisation of the muon beams for the Muon Ionisation Cooling Experiment

    International Nuclear Information System (INIS)

    Adams, D.; Barclay, P.; Bayliss, V.; Bradshaw, T.W.; Courthold, M.; Francis, V.; Fry, L.; Hayler, T.; Hills, M.; Lintern, A.; Macwaters, C.; Nichols, A.; Preece, R.; Ricciardi, S.; Rogers, C.; Stanley, T.; Tarrant, J.; Watson, S.; Wilson, A.; Adey, D.; Back, J.; Boyd, S.; Harrison, P.; Pidcott, C.; Taylor, I.; Alekou, A.; Apollonio, M.; Barber, G.; Colling, D.; Dobbs, A.; Dornan, P.; Fayer, S.; Fish, A.; Hunt, C.; Leaver, J.; Long, K.; Martyniak, J.; Middleton, S.; Pasternak, J.; Richards, A.; Santos, E.; Savidge, T.; Takahashi, M.; Asfandiyarov, R.; Blondel, A.; Graulich, J.S.; Karadzhov, Y.; Verguilov, V.; Wisting, H.; De Bari, A.; Cecchet, G.; Bayes, R.; Forrest, D.; Nugent, J.C.; Soler, F.J.P.; Walaron, K.; Bertoni, R.; Bonesini, M.; Lucchini, G.; Blackmore, V.J.; Carlisle, T.; Cobb, J.H.; Lau, W.; Rayner, M.A.; Tunnell, C.D.; Blot, S.; Kim, Y.K.; Bogomilov, M.; Kolev, D.; Rusinov, I.; Tsenov, R.; Vankova, G.; Booth, C.N.; Hodgson, P.; Nicholson, R.; Overton, E.; Robinson, M.; Smith, P.J.; Bowring, D.; DeMello, A.; Gourlay, S.; Li, D.; Prestemon, S.; Virostek, S.P.; Zisman, M.S.; Bravar, U.; Bross, A.D.; Fitzpatrick, T.; Leonova, M.; Moretti, A.; Neuffer, D.; Popovic, M.; Rubinov, P.; Rucinski, R.; Capponi, M.; Iaciofano, A.; Orestano, D.; Pastore, F.; Tortora, L.; Charnley, G.; Collomb, N.; Gallagher, A.; Grant, A.; Griffiths, S.; Hartnett, T.; Martlew, B.; Moss, A.; Muir, A.; Mullacrane, I.; Owens, P.; White, C.; Coney, L.; Fletcher, R.; Hanson, G.G.; Heidt, C.; Cooke, P.; Gamet, R.; Cremaldi, L.M.; Hart, T.L.; Luo, T.; Sanders, D.A.; Summers, D.J.; Dick, A.J.; Ronald, K.; Whyte, C.G.; Filthaut, F.; Freemire, B.; Hanlet, P.; Kafka, G.; Kaplan, D.M.; Rajaram, D.; Snopok, P.; Torun, Y.; Hansen, O.M.; Ramberger, S.; Vretenar, M.; Ishimoto, S.; Kuno, Y.; Sakamoto, H.; Kyberd, P.; Littlefield, M.; Nebrensky, J.J.; Onel, Y.; Palladino, V.; Palmer, R.B.; Roberts, T.J.

    2013-01-01

    A novel single-particle technique to measure emittance has been developed and used to characterise seventeen different muon beams for the Muon Ionisation Cooling Experiment (MICE). The muon beams, whose mean momenta vary from 171 to 281 MeV/c, have emittances of approximately 1.2-2.3 π mm-rad horizontally and 0.6-1.0 π mm-rad vertically, a horizontal dispersion of 90-190 mm and momentum spreads of about 25 MeV/c. There is reasonable agreement between the measured parameters of the beams and the results of simulations. The beams are found to meet the requirements of MICE. (orig.)

  16. Cryogenic current comparators for precise ion beam current measurements

    International Nuclear Information System (INIS)

    Kurian, Febin

    2015-01-01

    The planned Facility for Antiproton and Ion Research (FAIR) at GSI has to cope with a wide range of beam intensities in its high-energy beam transport systems and in the storage rings. To meet the requirements of a non-intercepting intensity measurement down to nA range, it is planned to install a number of Cryogenic Current Comparator (CCC) units at different locations in the FAIR beamlines. In this work, the first CCC system for intensity measurement of heavy ion beams, which was developed at GSI, was re-commissioned and upgraded to be used as a 'GSI - CCC prototype' for extensive optimization and development of an improved CCC for FAIR. After installation of a new SQUID sensor and related electronics, as well as implementation of improved data acquisition components, successful beam current measurements were performed at a SIS18 extraction line. The measured intensity values were compared with those of a Secondary Electron Monitor (SEM). Furthermore, the spill-structure of a slowly extracted beam was measured and analyzed, investigating its improvement due to bunching during the slow-extraction process. Due to the extreme sensitivity of the superconducting sensor, the determined intensity values as well as the adjustment of the system for optimal performance are strongly influenced by the numerous noise sources of the accelerators environment. For this reason, detailed studies of different effects caused by noise have been carried out, which are presented together with proposals to reduce them. Similarly, studies were performed to increase the dynamic range and overcome slew rate limitations, the results of which are illustrated and discussed as well. By combining the various optimizations and characterizations of the GSI CCC prototype with the experiences made during beam operation, criteria for a more efficient CCC System could be worked out, which are presented in this work. The details of this new design are worked out with respect to the

  17. LHC MD 652: Coupled-Bunch Instability with Smaller Emittance (all HOMs)

    CERN Document Server

    AUTHOR|(CDS)2081238; Timko, Helga; CERN. Geneva. ATS Department

    2017-01-01

    The aim of the MD was to measure the coupled-bunch stability from all HOM impedances, with a reduced longitudinal emittance in order to explore the HL-LHC conditions. The acceleration ramp was performed with the nominal beams of 2016, but a reduced target bunch length and RF voltage. With this reduced emittance, the beam remained close but above the single-bunch stability threshold. No coupled-bunch oscillations were observed, so we can conclude that the stability threshold for coupled-bunch instability is not lower than the single-bunch threshold. An interesting observation in the MD was the long-lasting injection oscillations, whose traces can still be seen at arrival to flat top; in agreement with observations in earlier MDs. The measurements took place between 28th October 20:00 and 29th October 05:10.

  18. PHYSICAL PROPERTIES OF Ly{alpha} EMITTERS AT z {approx} 0.3 FROM UV-TO-FIR MEASUREMENTS

    Energy Technology Data Exchange (ETDEWEB)

    Oteo, I.; Bongiovanni, A.; Perez Garcia, A. M.; Cepa, J.; Pintos-Castro, I. [Instituto de Astrofisica de Canarias (IAC), E-38200 La Laguna, Tenerife (Spain); Ederoclite, A. [Centro de Estudios de Fisica del Cosmos de Aragon, Plaza San Juan 1, Planta 2, Teruel, 44001 (Spain); Sanchez-Portal, M.; Altieri, B. [Herschel Science Centre (ESAC), Villafranca del Castillo (Spain); Perez-Martinez, R. [XMM/Newton Science Operations Centre (ESAC), Villafranca del Castillo (Spain); Lutz, D.; Berta, S.; Foerster Schreiber, N.; Genzel, R.; Magnelli, B. [Max-Planck-Institut fuer Extraterrestrische Physik (MPE), Postfach 1312, 85741 Garching (Germany); Andreani, P. [ESO, Karl-Schwarzchild-Str. 2, D-85748 Garching (Germany); Aussel, H.; Daddi, E.; Elbaz, D.; Le Floc' h, E. [Commissariat a l' Energie Atomique (CEA-SAp) Saclay (France); Cimatti, A. [Dipartimento di Astronomia, Universita di Bologna, Via Ranzani 1, 40127 Bologna (Italy); and others

    2012-06-01

    The analysis of the physical properties of low-redshift Ly{alpha} emitters (LAEs) can provide clues in the study of their high-redshift analogs. At z {approx} 0.3, LAEs are bright enough to be detected over almost the entire electromagnetic spectrum and it is possible to carry out a more precise and complete study than at higher redshifts. In this work, we examine the UV and IR emission, dust attenuation, star formation rate (SFR), and morphology of a sample of 23 GALEX-discovered star-forming LAEs at z {approx} 0.3 with direct UV (GALEX), optical (ACS), and FIR (PACS and MIPS) data. Using the same UV and IR limiting luminosities, we find that LAEs at z {approx} 0.3 tend to be less dusty, have slightly higher total SFRs, have bluer UV continuum slopes, and are much smaller than other galaxies that do not exhibit Ly{alpha} emission in their spectrum (non-LAEs). These results suggest that at z {approx} 0.3, Ly{alpha} photons tend to escape from small galaxies with low dust attenuation. Regarding their morphology, LAEs belong to Irr/merger classes, unlike non-LAEs. Size and morphology represent the most noticeable difference between LAEs and non-LAEs at z {approx} 0.3. Furthermore, the comparison of our results with those obtained at higher redshifts indicates either that the Ly{alpha} technique picks up different kind of galaxies at different redshifts or that the physical properties of LAEs are evolving with redshift.

  19. Four Dimensional Trace Space Measurement

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez, M.

    2005-02-10

    Future high energy colliders and FELs (Free Electron Lasers) such as the proposed LCLS (Linac Coherent Light Source) at SLAC require high brightness electron beams. In general a high brightness electron beam will contain a large number of electrons that occupy a short longitudinal duration, can be focused to a small transverse area while having small transverse divergences. Therefore the beam must have a high peak current and occupy small areas in transverse phase space and so have small transverse emittances. Additionally the beam should propagate at high energy and have a low energy spread to reduce chromatic effects. The requirements of the LCLS for example are pulses which contain 10{sup 10} electrons in a temporal duration of 10 ps FWHM with projected normalized transverse emittances of 1{pi} mm mrad[1]. Currently the most promising method of producing such a beam is the RF photoinjector. The GTF (Gun Test Facility) at SLAC was constructed to produce and characterize laser and electron beams which fulfill the LCLS requirements. Emittance measurements of the electron beam at the GTF contain evidence of strong coupling between the transverse dimensions of the beam. This thesis explores the effects of this coupling on the determination of the projected emittances of the electron beam. In the presence of such a coupling the projected normalized emittance is no longer a conserved quantity. The conserved quantity is the normalized full four dimensional phase space occupied by the beam. A method to determine the presence and evaluate the strength of the coupling in emittance measurements made in the laboratory is developed. A method to calculate the four dimensional volume the beam occupies in phase space using quantities available in the laboratory environment is also developed. Results of measurements made of the electron beam at the GTF that demonstrate these concepts are presented and discussed.

  20. A numerical study of emittance growths in RF guns

    CERN Document Server

    Masuda, K; Sobajima, M; Kitagaki, J; Ohnishi, M; Toku, H; Yoshikawa, K

    1999-01-01

    A beam with greatly reduced emittance is required for further improvements of FELs, in particular, for FELs of shorter wavelengths, and of narrower bandwidths. From this viewpoint, the BNL/SLAC/UCLA 1.6-cell S-band photocathode RF gun performance characteristics were calculated, first in order to evaluate what may contribute to the emittance growths in photocathode RF guns. We developed an RF gun to produce an electron beam with an extremely low emittance, by using a 2-D simulation code. It is found that, by optimizing the laser injection phase, the drive laser spot radius and the cavity shape around the laser spot, the beam emittance by the 1.6-cell RF gun can be greatly reduced to 2.1 pi mm mrad, from the previous 4.4 pi mm mrad of the original shape.

  1. Emittance preservation in plasma-based accelerators with ion motion

    Science.gov (United States)

    Benedetti, Carlo; Schroeder, Carl; Esarey, Eric E.; Leemans, Wim

    2017-10-01

    In a plasma-accelerator-based linear collider, the density of matched, low-emittance, high-energy particle bunches required for collider applications can be orders of magnitude above the background ion density, leading to ion motion, nonlinear focusing fields, and, hence, to beam emittance growth. By analyzing the response of the background ions to an ultra-high density beam, analytical expressions, valid for nonrelativistic ion motion, are derived for the transverse wakefield and for the final (i.e., after saturation) bunch emittance. Analytical results are validated against numerical modeling. A class of initial beam distributions are derived that are equilibrium solutions, which require head-to-tail bunch shaping, enabling emittance preservation with ion motion. This work was supported by the Director, Office of Science, Office of High Energy Physics, of the U.S. DOE under Contract No. DE-AC02-05CH11231.

  2. Computer codes for automatic tuning of the beam transport at the UNILAC

    International Nuclear Information System (INIS)

    Dahl, L.; Ehrich, A.

    1984-01-01

    For application in routine operation fully automatic computer controlled algorithms are developed for tuning of beam transport elements at the Unilac. Computations, based on emittance measurements, simulate the beam behaviour and evaluate quadrupole settings, in order to produce defined beam properties at specified positions along the accelerator. The interactive program is controlled using a graphic display on which the beam emittances and envelopes are plotted. To align the beam onto the ion-optical axis of the accelerator two automatic computer controlled procedures have been developed. The misalignment of the beam is determined by variation of quadrupole or steering magnet settings with simultaneous measurement of the beam distribution on profile grids. According to the result a pair of steering magnet settings are adjusted to bend the beam on the axis. The effects of computer controlled tuning on beam quality and operation are reported

  3. Turbulence measurement with a two-beam nacelle lidar

    DEFF Research Database (Denmark)

    Wagner, Rozenn; Sathe, Ameya; Mioullet, A.

    The analysis of the turbulence intensity measurement is performed for a lidar measuring horizontally with two beams. First the turbulence intensity measured by such a system was evaluated theoretically. The Mann model of turbulence was used to evaluate the true value of the turbulence intensity...... of the wind speed and the main effects of the lidar measurement principles on turbulence intensity measurement were modeled: - A lidar senses the wind speed over the probe volume acting as a low pass-filter and thus cannot resolve high frequency turbulence; - The horizontal wind speed is retrieved from...... the combination of the radial speeds measured along two line-of-sights with different orientations; this results in the contamination of the lidar turbulence intensity measurement from the transverse component of the wind field. Secondly, the theoretical results were compared to experimental measurements. A two...

  4. Characterization of electron bunches from field emitter array cathodes for use in next-generation x-ray free electron lasers

    International Nuclear Information System (INIS)

    Leemann, S. C.

    2007-01-01

    PSI is interested in developing an x-ray free electron laser (X-FEL) as a companion radiation source to the existing Swiss Light Source. In order to achieve radiation wavelengths as low as 1 Α, the X-FEL requires excellent electron beam quality and high beam energy. The energy requirements and thus the size and cost of the project can be reduced considerably if an ultra-low emittance electron source is developed. Therefore PSI has started the Low Emittance Gun Project with the aim to design a novel type of electron source that will deliver an electron beam with unprecedented emittance at high peak currents to the linear accelerator of the proposed X-FEL. A source candidate for such a gun is field emission from cold cathodes. In order to gain first experience with field emission guns, investigate the dynamics of space charge dominated electron beams and to develop diagnostics capable of resolving ultra-low emittances, it was decided to build a 100 keV DC gun test stand. In the scope of this thesis, the test stand has been designed, assembled and commissioned. For the first time, transverse phase space measurements of bunches emitted by field emitter arrays in pulsed DC accelerating fields have been performed. (author)

  5. Mini biased collimated faraday cups for measurement of intense pulsed ion beams

    International Nuclear Information System (INIS)

    He Xiaoping; Shi Lei; Zhang Jiasheng; Qiu Aici

    2000-01-01

    An analysis of principle of a biased Faraday cup for measuring ion beams density and the main reasons related to the measuring accuracy were presented. An array of mini biased collimated Faraday cups was manufactured for the measurement of ion beam density of a compact 200 keV high power ion beam source. In the experiments the maximum density of ion beam was in the center of the beam, and it was about 170 A/cm 2

  6. Beam loss control on the ISIS synchrotron simulations, measurements, upgrades

    CERN Document Server

    Warsop, C M

    2003-01-01

    The ISIS 800 MeV proton synchrotron presently provides 2.5*10/sup 13/ protons per pulse at 50 Hz, corresponding to a mean power of 160 kW. A dual harmonic RF system upgrade, now being installed, is expected to increase the intensity and power to about 3.75*10/sup 13/ ppp and 240 kW respectively. This paper describes work presently underway to understand and optimise beam loss control, which is a dominant factor determining operational performance. The main features of the collimation system are described, and Monte Carlo simulations of the loss control process are used to understand variations of efficiency with beam loss mode (growth rate, plane). Results of simulations are compared with measurements and operational data. Improvements to measurements are also outlined.

  7. Some TPC measurements in an oxygen beam at the AGS

    International Nuclear Information System (INIS)

    Love, W.A.; Etkin, A.; Foley, K.J.; Hackenburg, R.W.; Longacre, R.S.; Morris, T.W.; Platner, E.D.; Saulys, A.C.; Bonner, B.E.; Buchanan, J.A.; Chiou, C.N.; Clement, J.M.; Corcoran, M.D.; Krishna, N.; Kruk, J.W.; Miettinen, H.E.; Mutchler, G.S.; Nessi-Tedaldi, F.; Nessi, M.; Phillips, G.C.; Roberts, J.B.; Chan, C.S.; Kramer, M.A.; Hallman, T.J.; Madansky, L.; Lindenbaum, S.J.

    1989-01-01

    The principal detector for AGS Experiment 810 is a Time Projection Chamber (TPC) in which it is intended to measure momenta and angles of a major fraction of the charged particles from each light ion collision. This report describes the results of a test of a prototype of the TPC in a beam of (14.6x16=233.6 GeV/c) oxygen ions run in June of this year. (orig.)

  8. Invariant measures for stochastic nonlinear beam and wave equations

    Czech Academy of Sciences Publication Activity Database

    Brzezniak, Z.; Ondreját, Martin; Seidler, Jan

    2016-01-01

    Roč. 260, č. 5 (2016), s. 4157-4179 ISSN 0022-0396 R&D Projects: GA ČR GAP201/10/0752 Institutional support: RVO:67985556 Keywords : stochastic partial differential equation * stochastic beam equation * stochastic wave equation * invariant measure Subject RIV: BA - General Mathematics Impact factor: 1.988, year: 2016 http://library.utia.cas.cz/separaty/2016/SI/ondrejat-0453412.pdf

  9. Development of technique for quantifying gamma emitters in metal waste. New technique of precise and automatic measurements for confirmation of clearance level of metal waste

    International Nuclear Information System (INIS)

    Hattori, Takatoshi

    2002-01-01

    A New technique of precise and automatic measurements of gamma emitters in metal waste has been developed using 3D non-contact shape measurement and monte-carlo calculation techniques in order to confirm that specific radioactivity level of metal waste satisfies the clearance level and furthermore the surface contamination level of the metal waste is below the legal standard level. The technique can give a calibration factor every measurement target automatically and realize an automatic correction for reduction of background count rate in gamma measurements due to self-shield effect of the measurement target. The accuracy of the present method has been made clear using mock-metal wastes with various types of shape, number and size. Assuming the goal of the detection limit for practical use is 25OBq in radioactivity, a concept of the practical gamma monitor has been designed so as to be able to confirm both the clearance level and surface contamination level simultaneously and to cope with the metal waste at a speed of 2-10 ton a day. (author)

  10. Direct measurement of the beam deflection angle using the axial B-dot field

    Directory of Open Access Journals (Sweden)

    Xiaozhong He

    2011-05-01

    Full Text Available Beam position monitors are an important diagnostics tool for particle accelerator operation and related beam dynamics research. The measurement of the beam deflection angle, or moving direction of a charged particle beam with respect to the beam pipe axis, can provide useful additional information. Beam monitors sensitive to the beam’s azimuthal B-dot field (sometimes referred as B dots are used to measure the displacement (position of the beam centroid, as the beam generates a dipole term of the azimuthal magnetic field. Similarly, a dipole term of the axial magnetic field will be generated by the beam moving in a direction not parallel to the axis of the beam pipe. In this paper, a new method using the axial B-dot field is presented to measure the beam deflection angle directly, including the theoretical background. Simulations using the MAFIA numerical code have been performed, demonstrating a good agreement to the new established analytical model.

  11. Velocity bunching of high-brightness electron beams

    Directory of Open Access Journals (Sweden)

    S. G. Anderson

    2005-01-01

    Full Text Available Velocity bunching has been recently proposed as a tool for compressing electron beam pulses in modern high brightness photoinjector sources. This tool is familiar from earlier schemes implemented for bunching dc electron sources, but presents peculiar challenges when applied to high current, low emittance beams from photoinjectors. The main difficulty foreseen is control of emittance oscillations in the beam in this scheme, which can be naturally considered as an extension of the emittance compensation process at moderate energies. This paper presents two scenarios in which velocity bunching, combined with emittance control, is to play a role in nascent projects. The first is termed ballistic bunching, where the changing of relative particle velocities and positions occur in distinct regions, a short high gradient linac, and a drift length. This scenario is discussed in the context of the proposed ORION photoinjector. Simulations are used to explore the relationship between the degree of bunching, and the emittance compensation process. Experimental measurements performed at the UCLA Neptune Laboratory of the surprisingly robust bunching process, as well as accompanying deleterious transverse effects, are presented. An unanticipated mechanism for emittance growth in bends for highly momentum chirped beam was identified and studied in these experiments. The second scenario may be designated as phase space rotation, and corresponds closely to the recent proposal of Ferrario and Serafini. Its implementation for the compression of the electron beam pulse length in the PLEIADES inverse Compton scattering (ICS experiment at LLNL is discussed. It is shown in simulations that optimum compression may be obtained by manipulation of the phases in low gradient traveling wave accelerator sections. Measurements of the bunching and emittance control achieved in such an implementation at PLEIADES, as well as aspects of the use of velocity-bunched beam directly

  12. Modeling of antihydrogen beam formation for interferometric gravity measurements

    Science.gov (United States)

    Gerber, Sebastian

    2018-02-01

    In this paper a detailed computational study is performed on the formation of antihydrogen via three-body-recombination of positrons and antiprotons in a Penning trap with a specific focus on formation of a beam of antihydrogen. First, an analytical model is presented to calculate the formation process of the anti-atoms, the yield of the fraction leaving the recombination plasma volume and their angular velocity distribution. This model is then benchmarked against data from different antihydrogen experiments. Subsequently, the flux of antihydrogen towards the axial opening angle of a Penning trap is evaluated for its suitability as input beam into a Talbot–Lau matter interferometer. The layout and optimization of the interferometer to measure the acceleration of antihydrogen in the Earth’s gravitational field is numerically calculated. The simulated results can assist experiments aiming to measure the weak equivalence principle of antimatter as proposed by the AEgIS experiment (Testera et al 2015 Hyperfine Interact. 233 13–20). The presented model can further help in the optimization of beam-like antihydrogen sources for CPT invariance tests of antimatter (Kuroda et al 2014 Nat. Commun. 5 3089).

  13. DC proton beam measurements in a single-solenoid low-energy beam transport system

    International Nuclear Information System (INIS)

    Stevens, R.R. Jr.; Schafstall, P.; Schneider, J.D.; Sherman, J.; Zaugg, T.; Taylor, T.

    1994-01-01

    High current, CW proton accelerators are being considered for a number of applications including disposition of nuclear wastes, reduction of fissionable nuclear material inventories, safe production of critical nuclear materials, and energy production. All these applications require the development of high current, reliable, hydrogen ion injectors. In 1986, a program using CW RFQ technology was undertaken at CRL in collaboration with LANL and was continued there until 1993. During this time, an accelerator was built which produced 600 keV, 75 mA and 1,250 keV, 55 mA CW proton beams. The present program at Los Alamos using this accelerator is aimed at continuing the CRL work to demonstrate long-term reliability. In the present work, the authors are seeking to determine the optimal match to and the current limit of the 1,250-keV RFQ. This paper discusses the characterization of the 50 keV beams at the exit of the single-solenoid LEBT and presents both the experimental measurements and the beam simulations done to model this system

  14. Correction of beam-beam effects in luminosity measurement at ILC

    CERN Document Server

    Lukic, S

    2015-01-01

    Three methods for handling beam-beam effects in luminosity measurement at ILC are tested and evaluated in this work. The first method represents an optimization of the LEPtype asymmetric selection cuts that reduce the counting biases. The second method uses the experimentally reconstructed shape of the √ s ′ spectrum to determine the Beamstrahlung component of the bias. The last, recently proposed, collision-frame method relies on the reconstruction of the collision-frame velocity to define the selection function in the collision frame both in experiment and in theory. Thus the luminosity expression is insensitive to the difference between the CM frame of the collision and the lab frame. The collision-frame method is independent of the knowledge of the beam parameters, and it allows an accurate reconstruction of the luminosity spectrum above 80% of the nominal CM energy. However, it gives no precise infromation about luminosity below 80% of the nominal CM energy. The compatibility of diverse selection cut...

  15. Flat profile laser beam shaper

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Todd R.

    2017-09-12

    A system for shaping a beam comprises an emitter for emitting coherent electromagnetic radiation. Birefringent displacers are configured between the emitter and a target wherein the at least two birefringent displacers split the coherent electromagnetic radiation into a plurality of coherent parallel beams of electromagnetic radiation thereby producing a shaped wave front of the coherent parallel beams of electromagnetic radiation.

  16. Measurement of ultra-low ion energy of decelerated ion beam using a deflecting electric field

    Energy Technology Data Exchange (ETDEWEB)

    Thopan, P.; Suwannakachorn, D.; Tippawan, U. [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Yu, L.D., E-mail: yuld@thep-center.org [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayutthaya Road, Bangkok 10400 (Thailand)

    2015-12-15

    In investigation on ultra-low-energy ion bombardment effect on DNA, an ion beam deceleration lens was developed for high-quality ultra-low-energy ion beam. Measurement of the ion energy after deceleration was necessary to confirm the ion beam really decelerated as theoretically predicted. In contrast to conventional methods, this work used a simple deflecting electrostatic field after the deceleration lens to bend the ion beam. The beam bending distance depended on the ion energy and was described and simulated. A system for the measurement of the ion beam energy was constructed. It consisted of a pair of parallel electrode plates to generate the deflecting electrical field, a copper rod measurement piece to detect ion beam current, a vernier caliper to mark the beam position, a stepping motor to translate the measurement rod, and a webcam-camera to read the beam bending distance. The entire system was installed after the ion-beam deceleration lens inside the large chamber of the bioengineering vertical ion beam line. Moving the measurement rod across the decelerated ion beam enabled to obtain beam profiles, from which the beam bending distance could be known and the ion beam energy could be calculated. The measurement results were in good agreement with theoretical and simulated results.

  17. Laser Assisted Emittance Transfer for Storage Ring Lasing

    Energy Technology Data Exchange (ETDEWEB)

    Xiang, Dao; /SLAC

    2011-06-01

    In modern storage rings the transverse emittance of electron beams can be comparable to that from state-of-art photoinjectors, but the intrinsic low peak current and large energy spread pre-cludes the possibility of realizing short-wavelength high-gain free electron lasers (FELs) in storage rings. In this note I propose a technique to significantly increase beam peak current without greatly increasing beam energy spread, which is achieved by transferring part of the longitudinal emittance to transverse plane. It is shown that by properly repartitioning the emittance in 6-D phase space, the beam from a large storage ring may be used to drive a single-pass high-gain FEL in soft x-ray wavelength range.

  18. Phase-space measurement of stored electron beam at the Cornell Electron Storage Ring using a combination of slit array and CCD detector

    International Nuclear Information System (INIS)

    Cai, Z.; Lai, B.; Yun, W.; Gluskin, E.; Dejus, R.; Ilinski, P.

    1995-01-01

    A new technique for fast phase-space measurement has been developed and tested during a recent APS/CHESS undulator run. A measurement time of a few seconds was obtained by using a slit array and a high-resolution position sensitive detector system. The detector system consists of a CdWO 4 scintillation crystal, an optical imaging system, and a CCD detector. The short measurement time increases the measurement accuracy by reducing the effects from the instabilities of the electron beam in storage ring. The vertical emittance at the Cornell Electron Storage Ring in single-bunch and low-current mode was measured, and reasonable agreement with the expected values for both source size and source divergence were obtained (σ y =75 μm and σ y' =12 μrad). The effects of the finite size of the first slit on the measurement results are discussed, and a comprehensive data analysis procedure is described

  19. Cancer from internal emitters

    International Nuclear Information System (INIS)

    Boecker, B.B.; Griffith, W.C. Jr.

    1995-01-01

    Irradiation from internal emitters, or internally deposited radionuclides, is an important component of radiation exposures encountered in the workplace, home, or general environment. Long-term studies of human populations exposed to various internal emitters by different routes of exposure are producing critical information for the protection of workers and members of the general public. The purpose of this report is to examine recent developments and discuss their potential importance for understanding lifetime cancer risks from internal emitters. The major populations of persons being studied for lifetime health effects from internally deposited radionuclides are well known: Lung cancer in underground miners who inhaled Rn progeny, liver cancer from persons injected with the Th-containing radiographic contrast medium Thorotrast, bone cancer from occupational or medical intakes of 226 Ra or medical injections of 224 Ra, and thyroid cancer from exposures to iodine radionuclides in the environment or for medical purposes

  20. Transport and emittance study for 18 GHz superconducting-ECR ion source at RCNP.

    Science.gov (United States)

    Yorita, T; Hatanaka, K; Fukuda, M; Ueda, H; Kibayashi, M; Morinobu, S; Tamii, A

    2012-02-01

    As the upgrade program of the azimuthally varying field (AVF) cyclotron is at the cyclotron facility of the RCNP, Osaka University for the improvement of the quality, stability, and intensity of accelerated beams, an 18 GHz superconducting (SC) ECR ion source has been installed to increase beam currents and to extend the variety of ions, especially for highly charged heavy ions which can be accelerated by RCNP AVF cyclotron. The production development of several ions such as B, O, N, Ne, Ar, Ni, Kr, and Xe has been performed by Yorita et al. [Rev. Sci. Instrum. 79, 02A311(2008); 81, 02A332 (2010)]. Further studies for the beam transport have been done in order to improve the beam current more for injection of cyclotron. The effect of field leakage of AVF main coil is not negligible and additional steering magnet has been installed and then beam transmission has been improved. The emittance monitor has also been developed for the purpose of investigating correlation between emittance of beam from ECR ion sources and injection efficiency. The monitor consists with BPM82 with rotating wire for fast measurement for efficient study.

  1. Ultrarelativistic electron beam spatial size estimation from angular distribution emission in thin crystals

    Energy Technology Data Exchange (ETDEWEB)

    Goponov, Yu.A.; Sidnin, M.A. [Belgorod National Research University, Belgorod (Russian Federation); Sumitani, K.; Takabayashi, Y. [SAGA Light Source, 8-7 Yayoigaoka, Tosu, Saga 841-0005 (Japan); Vnukov, I.E., E-mail: vnukov@bsu.edu.ru [Belgorod National Research University, Belgorod (Russian Federation)

    2016-02-01

    The use of ultrarelativistic electron (positron) emission in thin crystals to estimate particle beam spatial sizes for projected electron–positron colliders is proposed. The existing position-sensitive X-ray range detectors restrict the minimum value of the measured beam size to a level of approximately 10 μm, which is far greater than the planned sizes of collider beams. We propose to estimate the electron (positron) beam divergence over the diffracted transition radiation from angular distribution measurements. The spatial size can be obtained from the calculated beam emittance or the experimental emittance, which is measured during the earlier stage of acceleration using optical transition or optical diffraction radiation. The problem of crystal destruction under the influence of a high-intensity electron beam is discussed. The use of surface parametric X-ray radiation, where the problem of crystal destruction is almost absent, to measure the electron beam parameters is also discussed.

  2. Ultrarelativistic electron beam spatial size estimation from angular distribution emission in thin crystals

    Science.gov (United States)

    Goponov, Yu. A.; Sidnin, M. A.; Sumitani, K.; Takabayashi, Y.; Vnukov, I. E.

    2016-02-01

    The use of ultrarelativistic electron (positron) emission in thin crystals to estimate particle beam spatial sizes for projected electron-positron colliders is proposed. The existing position-sensitive X-ray range detectors restrict the minimum value of the measured beam size to a level of approximately 10 μm, which is far greater than the planned sizes of collider beams. We propose to estimate the electron (positron) beam divergence over the diffracted transition radiation from angular distribution measurements. The spatial size can be obtained from the calculated beam emittance or the experimental emittance, which is measured during the earlier stage of acceleration using optical transition or optical diffraction radiation. The problem of crystal destruction under the influence of a high-intensity electron beam is discussed. The use of surface parametric X-ray radiation, where the problem of crystal destruction is almost absent, to measure the electron beam parameters is also discussed.

  3. Substrate heating measurements in pulsed ion beam film deposition

    Energy Technology Data Exchange (ETDEWEB)

    Olson, J.C.; Davis, H.A.; Rej, D.J.; Waganaar, W.J. [Los Alamos National Lab., NM (United States); Tallant, D.R. [Cornell Univ., Ithaca, NY (United States). Materials Science and Engineering Dept.; Thompson, M.O. [Sandia National Labs., Albuquerque, NM (United States)

    1995-05-01

    Diamond-like Carbon (DLC) films have been deposited at Los Alamos National Laboratory by pulsed ion beam ablation of graphite targets. The targets were illuminated by an intense beam of hydrogen, carbon, and oxygen ions at a fluence of 15-45 J/cm{sup 2}. Ion energies were on the order of 350 keV, with beam current rising to 35 kA over a 400 ns ion current pulse. Raman spectra of the deposited films indicate an increasing ratio of sp{sup 3} to sp{sup 2} bonding as the substrate is moved further away from the target and further off the target normal. Using a thin film platinum resistor at varying positions, we have measured the heating of the substrate surface due to the kinetic energy and heat of condensation of the ablated material. This information is used to determine if substrate heating is responsible for the lack of DLC in positions close to the target and near the target normal. Latest data and analysis will be presented.

  4. Measuring g with a beam of antihydrogen (AEgIS)

    CERN Document Server

    Canali, C

    2011-01-01

    The gravitational interaction between matter and antimatter has never been tested experimentally. According to some attempts to unify gravity with the other forces, the possibility that $g(p) 6= g\\bar{(p)}$ cannot be excluded 1 . The AEGIS experiment 2 intends to measure for the first time the gravitational acceleration of antimatter using cold antihydrogen atoms. Antihydrogen atoms will be obtained trough a charge exchange process between Rydberg positronium atoms and antiprotons. Once $\\bar{H}$ are accelerated to form a horizontal beam, they travel through a Moire deflectometer, able to measure the vertical displacement of atoms due to gravity. Knowing the velocity of the antiatoms from the time of flight measurement and the length of the flight path allows to estimate the gravity acceleration g for antihydrogen. With this setup an initial precision on the measure of g of 1% is expected.

  5. The activity of γ-emitters as measured by ionisation chambers the determination of the specific emission coefficient γ for some radio-elements (1961)

    International Nuclear Information System (INIS)

    Engelmann, J.

    1962-06-01

    The object of this work is to study techniques of measurement using the gamma ionisation chamber, making it possible either to measure the activities of radioactive sources, or to determine the specific emission coefficient γ (or the coefficient K) of a given radioelement. The ionisation chambers studied belong to two categories: graphites cavity-chambers, and 4 π γ chambers. For the cavity-chamber measurements, the different correction factors of which account must be taken have been calculated, in particular the geometric and hygrometric corrections. The absorption and auto-absorption corrections have led to the introduction of the notion of the 'effective energy γ' of a radioelement. In the case of 4 π γ chambers, it has been shown that appropriately shaped electrodes make it possible to improve their performances. One of the chambers described permits the measurement of β emitters using the associated Bremsstrahlung. In order to measure the K coefficient of some radioelements, it has been found useful a 4 π γ chamber with graphite walls, the measurement being carried out by comparison with a radium standard. The validity of the method was checked with radioelements for whom the K coefficient values are well-known ( 24 Na, 60 Co, 131 I, 198 Au). For other radioelements, the following values were obtained (expressed in r cm 3 mc -1 h -1 ): 51 Cr: 0,18; 56 Mn: 8,8; 65 Zn: 3,05; 124 Sb: 9,9; 134 Cs: 9,3; 137 Cs: 3,35; 141 Ce: 0,46; 170 Tm: 0,023; 192 Ir: 24,9; 203 Hg: 1,18; These values have been corrected for the contribution to the dose of the fluorescent radiation which may be emitted by the source, except in the case of Tm 170 . In the last part of this work, the performances of the different electro-metric devices used were compared. (author) [fr

  6. Beam Spin Asymmetry Measurements for Two Pion Photoproduction at CLAS

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Mark D. [Univ. of Glasgow, Scotland (United Kingdom)

    2015-09-01

    The overarching goal of this analysis, and many like it, is to develop our understanding of the strong force interactions within the nucleon by examining the nature of their excitation spectra. As the resonances of these spectra have very short lifetimes (tau = 1x10-23 s) and often have very similar masses, it is often impossible to directly observe resonances in the excitation spectra of nucleons. Polarization observables allow us to study the resonances by looking at how they affect the spin state of final state particles. The beam asymmetry is a polarization observable that allows us to detect the sensitivity of these resonances, and other transition mechanisms, to the electric vector orientation of incident photons. Presented in this thesis are first measurements of the beam asymmetries in the resonant region for the reaction channel pgamma p --> p π+ π-focusing on the intermediate mesonic states rho^0 and f^0, and the final state pions. The analysis used data from the g8b experiment undertaken at the Thomas Jefferson National Accelerator Facility (JLab), the first experiment at JLab to use a linearly polarized photon beam. Using the coherent Bremsstrahlung facility and the CLAS detector of Hall B at JLab allowed for many multi-channel reactions to be detected and the first measurements of many polarization observables including those presented here. A brief overview of the theoretical framework used to undertake this analysis is given, followed by a description of the experimental details of the facilities used, then a description of the calibration of the Bremsstrahlung tagging facility which the author undertook, and finally the analysis is presented and the resulting measurements.

  7. Electron Beam Polarization Measurement Using Touschek Lifetime Technique

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Changchun; /Duke U., DFELL; Li, Jingyi; /Duke U., DFELL; Mikhailov, Stepan; /Duke U., DFELL; Popov, Victor; /Duke U., DFELL; Wu, Wenzhong; /Duke U., DFELL; Wu, Ying; /Duke U., DFELL; Chao, Alex; /SLAC; Xu, Hong-liang; /Hefei, NSRL; Zhang, Jian-feng; /Hefei, NSRL

    2012-08-24

    Electron beam loss due to intra-beam scattering, the Touschek effect, in a storage ring depends on the electron beam polarization. The polarization of an electron beam can be determined from the difference in the Touschek lifetime compared with an unpolarized beam. In this paper, we report on a systematic experimental procedure recently developed at Duke FEL laboratory to study the radiative polarization of a stored electron beam. Using this technique, we have successfully observed the radiative polarization build-up of an electron beam in the Duke storage ring, and determined the equilibrium degree of polarization and the time constant of the polarization build-up process.

  8. An Automatic System for Determining Solar Absorptance and Thermal Emittance of Surfaces from Spectral Normal Reflectance Measurements

    National Research Council Canada - National Science Library

    Teichman, Louis

    1965-01-01

    .... The system consists of two spectrophotometers used to make optical reflectance measurements, electronic digitizing equipment to record the data, and a high-speed electronic computer to calculate the desired results...

  9. Laboratory Measurements of Electrostatic Solitary Structures Generated by Beam Injection

    International Nuclear Information System (INIS)

    Lefebvre, Bertrand; Chen, Li-Jen; Gekelman, Walter; Pribyl, Patrick; Vincena, Stephen; Kintner, Paul; Pickett, Jolene; Chiang, Franklin; Judy, Jack

    2010-01-01

    Electrostatic solitary structures are generated by injection of a suprathermal electron beam parallel to the magnetic field in a laboratory plasma. Electric microprobes with tips smaller than the Debye length (λ De ) enabled the measurement of positive potential pulses with half-widths 4 to 25λ De and velocities 1 to 3 times the background electron thermal speed. Nonlinear wave packets of similar velocities and scales are also observed, indicating that the two descend from the same mode which is consistent with the electrostatic whistler mode and result from an instability likely to be driven by field-aligned currents.

  10. Comparison of cone beam computed tomography imaging with physical measures.

    Science.gov (United States)

    Stratemann, S A; Huang, J C; Maki, K; Miller, A J; Hatcher, D C

    2008-02-01

    The goal of this study was to determine the accuracy of measuring linear distances between landmarks commonly used in orthodontic analysis on a human skull using two cone beam CT (CBCT) systems. Measurements of length were taken using volumetric data from two CBCT systems and were compared with physical measures using a calliper applied to one human adult skull. Landmarks were identified with chromium steel balls embedded at 32 cranial and 33 mandibular landmarks and the linear measures were taken with a digital calliper. The skull was then scanned with two different CBCT systems: the NewTom QR DVT 9000 (Aperio Inc, Sarasota, FL) and the Hitachi MercuRay (Hitachi Medico Technology, Tokyo, Japan). CT data including the landmark point data were threshold segmented using CyberMed's CB Works software (CB Works 1.0, CyberMed Inc., Seoul, Korea). The resulting segmentations were exported from CB Works as VRML (WRL) files to Amira software (Amira 3.1, Mercury Computer Systems GmbH, Berlin, Germany). The error was small compared with the gold standard of the physical calliper measures for both the NewTom (0.07+/-0.41 mm) and CB MercuRay (0.00+/-0.22 mm) generated data. Absolute error to the gold standard was slightly positive, indicating minor compression relative to the calliper measurement. The error was slightly smaller in the CB MercuRay than in the NewTom, probably related to a broader greyscale range for describing beam attenuation in 12-bit vs 8-bit data. The volumetric data rendered with both CBCT systems provided highly accurate data compared with the gold standard of physical measures directly from the skulls, with less than 1% relative error.

  11. Neutral beam power measurements inside the ASDEX torus

    International Nuclear Information System (INIS)

    Zengliang, Y.; Staebler, A.; Vollmer, O.

    1982-11-01

    Neutral beam power measurements inside the ASDEX torus are done with a retractable calorimeter which is only radiation cooled. The calorimeter plate made from Molybdenum is subdivided into nine segments whose increase in energy content due to a shot yields the absorbed beam power. Different models for the backward extrapolation of the measured temperature curves are examined for a series of low energy shots with the result that pure radiation cooling is a valid assumption. Furthermore, a temperature correction to the measured power is derived from these experiments. The evaluation of the shots onto this calorimeter is done by a computer program. The application of this program to a few full power shots shows that a neutral power up to 3.2 MW has been injected into the ASDEX vessel by the two injectors with an overall efficiency of up to 40%. Reionization losses due to the ASDEX stray field are less than 10%; they do not show any dependence upon the pulse length for shots up to 200 ms. (orig.)

  12. Measuring charge density of electron beam single nanosecond pulses

    International Nuclear Information System (INIS)

    Gonchar, A.I.; Nesterenko, V.S.; Fazkullin, V.A.

    1982-01-01

    A description is presented of a probe design and electrometric repeater circuit and technique for measuring the charge (current) density of electron beam single pulses by integrating current at a reference capacitor with a subsequent registering of voltage across the capacitor. The probe consists of a band-type signal electrodes and two oval cross-section sleeves: external and internal with larger and smaller rectangular openings, respectively. The external sleeve has antidynatron grid located over the hole. The design employs integer nickel sleever - the cores of electron tube cathodes. The signal electrode is made of nickel band 0.15 mm thick. The probe elements are insulated from each other along the whole length with a layer of teflon band (30 μm), with rectangular openings cut in compliance with the sleeve openings. The measurement range is from 0.4x10 - 9 to 1x10 - 7 C/cm 2 . The rated accuracy of measurements is no worse than +-5% for the beam energy of 0.2 to 3 KeV. The ultimate parameters the charge density - 6 C/cm 2 and direct current density 3 mA/cm 2 - are specified by the breakdown voltage (200 V) of the input capacitor and probe insulation

  13. 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

  14. Beam-based alignment and tuning procedures for e+e- collider final focus systems

    International Nuclear Information System (INIS)

    Bulos, F.; Burke, D.; Helm, R.; Irwin, J.; Odian, A.; Roy, G.; Ruth, R.; Yamamoto

    1991-01-01

    For future linear colliders, with very small emittances and beam sizes and demanding tolerances on final focus system alignment and magnet errors, it becomes increasingly important to use the beam as a diagnostic tool. The authors report here procedures they have identified and will be implemented in the Final Focus Test Beam at SLAC incorporating (1) quadrupole strength changes, (2) central orbit modifications, (3) spot size measurements, and (4) beam stability monitoring

  15. Beam-based alignment and tuning procedures for e+e- collider final focus systems

    International Nuclear Information System (INIS)

    Bulos, F.; Burke, D.; Helm, R.; Irwin, J.; Odian, A.; Roy, G.; Ruth, R.; Yamamoto, N.

    1991-05-01

    For future linear colliders, with very small emittances and beam sizes and demanding tolerances on final focus system alignment and magnet errors, it becomes increasingly important to use the beam as a diagnostic tool. We report here procedures we have identified and will be implemented in the Final Focus Test Beam at SLAC incorporating (1) quadrupole strength changes, (2) central orbit modifications, (3) spot size measurements, and (4) beam stability monitoring. 3 refs., 4 figs., 3 tabs

  16. Secondary beam line phase space measurement and modeling at LAMPF

    International Nuclear Information System (INIS)

    Floyd, R.; Harrison, J.; Macek, R.; Sanders, G.

    1979-01-01

    Hardware and software have been developed for precision on-line measurement and fitting of secondary beam line phase space parameters. A system consisting of three MWPC planes for measuring particle trajectories, in coincidence with a time-of-flight telescope and a range telescope for particle identification, has been interfaced to a computer. Software has been developed for on-line track reconstruction, application of experimental cuts, and fitting of two-dimensional phase space ellipses for each particle species. The measured distributions have been found to agree well with the predictions of the Monte Carlo program DECAY TURTLE. The fitted phase space ellipses are a useful input to optimization routines, such as TRANSPORT, used to search for superior tunes. Application of this system to the LAMPF Stopped Muon Channel is described

  17. Imaging and Measuring Electron Beam Dose Distributions Using Holographic Interferometry

    DEFF Research Database (Denmark)

    Miller, Arne; McLaughlin, W. L.

    1975-01-01

    Holographic interferometry was used to image and measure ionizing radiation depth-dose and isodose distributions in transparent liquids. Both broad and narrowly collimated electron beams from accelerators (2–10 MeV) provided short irradiation times of 30 ns to 0.6 s. Holographic images...... and measurements of absorbed dose distributions were achieved in liquids of various densities and thermal properties and in water layers thinner than the electron range and with backings of materials of various densities and atomic numbers. The lowest detectable dose in some liquids was of the order of a few k......Rad. The precision limits of the measurement of dose were found to be ±4%. The procedure was simple and the holographic equipment stable and compact, thus allowing experimentation under routine laboratory conditions and limited space....

  18. Development and calibration of a portable detection device for in vivo measurement of high-energy photon emitters incorporated by humans

    International Nuclear Information System (INIS)

    Soares, A.B.; Arbach, M.N.; Lucena, E.A.; Dantas, A.L.A.; Dantas, B.M.

    2017-01-01

    This work presents the evaluation of the applicability and sensitivity of a portable detection device specially designed for in vivo measurement of high-energy photon emitters in the human body. The calibration was performed at the In-Vivo Monitoring Laboratory of the IRD. The equipment consists of a lead-collimated NaI (Tl) 3″ x 3″ scintillation detector assembled on a tripod. The detector and its compact associated electronics are connected via USB cable to a portable PC. Spectrum acquisition and analysis is controlled by specific commercially available software. The calibration was performed using a standard liquid source of 152 Eu contained in 3 L polyethylene bottles. The evaluation of the system is based on the estimation of the minimum committed effective doses associated to the minimum detectable activities, calculated using current biokinetic and dosimetric models available in the literature. The dose detection limits for selected radionuclides of interest in an emergency scenario have shown to be far below 1 mSv allowing the system to be useful in accident situations. (author)

  19. Absolute measurement of {beta} emitters with a 4 {pi} counter; Mesure absolue des emetteurs {beta} au compteur 4 {pi}

    Energy Technology Data Exchange (ETDEWEB)

    Le Gallic, Y. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1959-06-15

    The object of this work is to investigate the conditions under which the activity of {beta}-emitting radionuclides may be measured with a maximum of precision, and as a result to study the relevant corrections. The various problems relating to activity measurements with a 4 {pi} counter have been examined successively: - comparison of 4 {pi}, GM and proportional counters; - study of the preparation of sources; - corrections on the counting of sources; - self-absorption; - correction for absorption. The precision obtained on these measurements varies from 1.2 to 3 per cent, with the result that the 4 {pi} counter can be considered a very satisfactory calibration instrument. (author) [French] Le but de ce travail est de rechercher les conditions permettant d'obtenir avec le maximum de precision, la mesure de l'activite des radionuclides se desintegrant par emission et par consequent d'etudier les corrections qui s'y rapportent. Nous avons examine successivement les differents problemes se rapportant aux mesures d'activite au compteur 4 {pi}: - Comparaison des compteurs 4 {pi}, GM et proportionnel; - etude de la preparation des sources; - corrections sur la numeration des sources; - auto-absorption; - correction d'absorption. La precision obtenue dans ces mesures, variant de 1,2 a 3 pour cent, on peut donc considerer le compteur 4 {pi} comme un instrument d'etalonnage tres satisfaisant. (auteur)

  20. Analysis of emittance compensation and simulation results to photo-cathode RF gun

    CERN Document Server

    LiuShengGuang

    2002-01-01

    The emittance compensation technology will be used on the photo-cathode RF gun for Shanghai SDUV-FEL. The space charge force and its effect on electron beam transverse emittance in RF gun is studied, the principle of emittance compensation in phase-space is discussed. The authors have designed a compensation solenoid and calculated its magnetic field distribution. Its performance has been studied by the code PARMELA. A simulation result indicates that the normalized transverse RMS emittance for electron beam of 1.5 nC is 1.612 pi mm centre dot mrad, electron energy E = 5.71 MeV

  1. First Beam Test of Nanometer Spot Size Monitor Using Laser Interferometry

    CERN Document Server

    Walz, D

    2003-01-01

    The nanometer spot size monitor based on the laser interferometry (Laser-Compton Spot Size Monitor) has been tested in FFTB beam line at SLAC. A low emittance beam of 46 GeV electrons, provided by the two-mile linear accelerator, was focused into nanometer spot in the FFTB line, and its transverse dimensions were precisely measured by the spot size monitor.

  2. Paired emitter-detector light emitting diodes for the measurement of lead(II) and cadmium(II)

    International Nuclear Information System (INIS)

    Lau, K.-T.; McHugh, Eimear; Baldwin, Susan; Diamond, Dermot

    2006-01-01

    A transmittance mode optical device based on using a reverse biased light emitting diode (LED) as light detector has been developed for colorimetric analysis. This new optical device was validated with bromocresol green dye for absorbance measurements before being employed for detecting cadmium(II) and lead(II) in water. Results show that the performance of this LED-based device is comparable to much more expensive bench top UV-vis instruments, but with the advantages of being low cost, low power and simple to operate

  3. The separated-sector cyclotron: beam transport

    International Nuclear Information System (INIS)

    1989-01-01

    The diagnostic components that were ordered for the rest of the proposed beamlines at the NAC have been delivered. Design and manufacture of a special harp for the beam swinger has commenced. The Faraday cups and slits in the transfer beamline were replaced by water-cooled versions, owing to the decision to transport beams of higher intensity than initially specified. A prototype water-cooled slit for use in the low-energy beamline emittance measurement system has been installed, replacing the previous uncooled slit, to meet the requirement to measure the emittance of high-intensity beams. Software to automate the emittance measurement procedure is being developed. The method of calibration and alignment of the beamline scanners has been improved resulting in a more accurate measurement of the beam position. Software is being developed to regulate the beam current on the neutron therapy target. Current measurement from the target is used as feedback to regulate the aperture of a slit-system in the low-energy transfer beamline. This procedure will be implemented as soon as final tests have been carried out during the next scheduled shutdown. 3 figs

  4. 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.

  5. Beam Measurements of a CLOUD (Cosmics Leaving OUtdoor Droplets) Chamber

    CERN Document Server

    Kirkby, Jasper

    2001-01-01

    A striking correlation has recently been observed between global cloud cover and the flux of incident cosmic rays. The effect of natural variations in the cosmic ray flux is large, causing estimated changes in the Earth's energy radiation balance that are comparable to those attributed to greenhouse gases from the burning of fossil fuels since the Industrial Revolution. However a direct link between cosmic rays and cloud formation has not been unambiguously established. We therefore propose to experimentally measure cloud (water droplet) formation under controlled conditions in a test beam at CERN with a CLOUD chamber, duplicating the conditions prevailing in the troposphere. These data, which have never been previously obtained, will allow a detailed understanding of the possible effects of cosmic rays on clouds and confirm, or otherwise, a direct link between cosmic rays, global cloud cover and the Earth's climate. The measurements will, in turn, allow more reliable calculations to be made of the residual e...

  6. 'Crystal Collimator' Measurement of CESR particle-beam Source Size

    International Nuclear Information System (INIS)

    Finkelstein, K.D.; Bazarov, Ivan; White, Jeffrey; Revesz, Peter

    2004-01-01

    We have measured electron and positron beam source size at CHESS when the Cornell Electron Storage Ring (CESR) is run dedicated for the production of synchrotron radiation. Horizontal source size at several beamlines is expected to shrink by a factor of two but synchrotron (visible) light measurements only provide the vertical size. Therefore a 'crystal collimator' using two Bragg reflection in dispersive (+,+) orientation has been built to image the horizontal (vertical) source by passing x-rays parallel to within 5 microradians to an imaging screen and camera. With the 'crystal collimator' we observe rms sizes of 1.2 mm horizontal by 0.28 mm vertical, in good agreement with the 1.27 mm size calculated from lattice functions, and 0.26 mm observed using a synchrotron light interferometer

  7. Measuring the self-healing of the spatially inhomogeneous states of polarization of vector Bessel beams

    CSIR Research Space (South Africa)

    Milione, G

    2015-02-01

    Full Text Available We experimentally measured the self-healing of the spatially inhomogeneous states of polarization of vector Bessel beams. Radially and azimuthally polarized vector Bessel beams were experimentally generated via a digital version of Durnin's method...

  8. Application of a transverse phase-space measurement technique for high-brightness, H- beams to the GTA H- beam

    International Nuclear Information System (INIS)

    Johnson, K.F.; Garcia, R.C.; Rusthoi, D.P.; Sander, O.R.; Sandoval, D.P.; Shinas, M.A.; Smith, M.; Yuan, V.W.; Connolly, R.C.

    1995-01-01

    The Ground Test Accelerator (GTA) had the objective Of Producing a high-brightness, high-current H-beam. The major components were a 35 keV injector, a Radio Frequency Quadrupole (RFQ), an intertank matching section (IMS), and a drift tube linac (DTL), consisting of 10 modules. A technique for measuring the transverse phase-space of high-power density beams has been developed and tested. This diagnostic has been applied to the GTA H-beam. Experimental results are compared to the slit and collector technique for transverse phase-space measurements and to simulations

  9. Industrial application of electron sources with plasma emitters

    CERN Document Server

    Belyuk, S I; Rempe, N G

    2001-01-01

    Paper contains a description, operation, design and parameters of electron sources with plasma emitters. One presents examples of application of these sources as part of automated electron-beam welding lines. Paper describes application of such sources for electron-beam deposition of composite powders. Electron-beam deposition is used to rebuild worn out part and to increase strength of new parts of machines and tools. Paper presents some examples of rebuilding part and the advantages gained in this case

  10. Device for the radiation centering at electron emitters

    International Nuclear Information System (INIS)

    Panzer, S.; Ardenne, T. von; Jessat, K.; Bahr, G.

    1985-01-01

    The invention has been directed at a device for a simplified and reliable centering of electron beams at electron emitters in particular for welding and thermal surface modifications. The electron beam has been focussed relatively to an electron-optical lens. A movable masked electron detector has been arranged at the electron beam deflection plane. The electron detector is connected with an electronic data evaluation equipment

  11. Space Charge Compensation in the Linac4 Low Energy Beam Transport Line with Negative Hydrogen Ions

    CERN Document Server

    Valerio-Lizarraga, C; Leon-Monzon, I; Lettry, J; Midttun, O; Scrivens, R

    2014-01-01

    The space charge effect of low energy, unbunched ion beams can be compensated by the trapping of ions or electrons into the beam potential. This has been studied for the 45 keV negative hydrogen ion beam in the CERN Linac4 Low Energy Beam Tranport (LEBT) using the package IBSimu1, which allows the space charge calculation of the particle trajectories. The results of the beam simulations will be compared to emittance measurements of an H- beam at the CERN Linac4 3 MeV test stand, where the injection of hydrogen gas directly into the beam transport region has been used to modify the space charge compensation degree.

  12. Modified theoretical minimum emittance lattice for an electron storage ring with extreme-low emittance

    Directory of Open Access Journals (Sweden)

    Yi Jiao

    2011-05-01

    Full Text Available In the continuing efforts to reduce the beam emittance of an electron storage ring composed of theoretical minimum emittance (TME lattice, down to a level of several tens of picometers, nonlinear dynamics grows to be a great challenge to the performance of the storage ring because of the strong sextupoles needed to compensate for its large global natural chomaticities coupled with its small average dispersion function. To help in dealing with the challenge of nonlinear optimization, we propose a novel variation of theoretical minimum emittance (TME lattice, named as “modified-TME” lattice, with minimal emittance about 3 times of the exact theoretical minimum, while with more compact layout, lower phase advance per cell, smaller natural chromaticities, and more relaxed optical functions than that in a TME cell, by using horizontally defocusing quadrupole closer to the dipole or simply combined-function dipole with horizontally defocusing gradient. We present approximate scaling formulas to describe the relationships of the design parameters in a modified-TME cell. The applications of modified-TME lattice in the PEP-X storage ring design are illustrated and the proposed lattice appears a good candidate for synchrotron radiation light source with extremely low emittance.

  13. MD 382: Beam Transfer Function and diffusion mechanisms

    CERN Document Server

    Tambasco, Claudia; Buffat, Xavier; Crouch, Matthew; Pieloni, Tatiana; Boccardi, Andrea; Fuchsberger, Kajetan; Gasior, Marek; Kotzian, Gerd; Lefevre, Thibaut; Pojer, Mirko; Salvachua Ferrando, Belen Maria; Solfaroli Camillocci, Matteo; Giachino, Rossano; CERN. Geneva. ATS Department

    2016-01-01

    The Beam Transfer Function (BTF) measurements have been previously tested in the LHC during MD block 1 and 2. Different machine configurations (i.e. energy, beam intensity, emittance etc...) have been tested to determine a safe set-up (excitation amplitude) of the system to be completely transparent to the beam (no emittance blow-up neither losses). The aim of this experiment in MD block 3 was to characterize the Stability Diagram (SD) in the presence of diffusion mechanisms induced by excited resonances due to beam-beam long range and Landau octupole interplay. During the experiment, BTF measurements have been acquired at flat top for different settings of Landau octupole current, different chromaticity values and transverse feedback gains. In this note the description of the experiment is presented together with some preliminary results.

  14. DC-SC Photoinjector with Low Emittance at Peking University

    CERN Document Server

    Xiang Rong; Hao, J; Huang, Senlin; Lu Xiang Yang; Quan, Shengwen; Zhang, Baocheng; Zhao, Kui

    2005-01-01

    High average power Free Electron Lasers require the high quality electron beams with the low emittance and the sub-picosecond bunches. The design of DC-SC photoinjector, directly combining a DC photoinjector with an SRF cavity, can produce high average current beam with moderate bunch charge and high duty factor. Because of the DC gun, the emittance increases quickly at the beginning, so a carefully design is needed to control that. In this paper, the simulation of an upgraded design has been done to lower the normalized emittance below 1.5mm·mrad. The photoinjector consists of a DC gap and a 2+1/2-cell SRF cavity, and it is designed to produce 4.2 MeV electron beams at 100pC bunch charge and 81.25MHz repetition rate (8 mA average current).

  15. Measuring micron size beams in the SLC final focus

    International Nuclear Information System (INIS)

    McCormick, D.; Ross, M.; DeBarger, S.

    1994-10-01

    A pair of high resolution wire scanners have been built and installed in the SLC final focus. The final focus optics uses a set of de-magnifying telescopes, and an ideal location for a beam size monitor is at one of the magnified image points of the interaction point. The image point chosen for these scanners is in the middle of a large bend magnet. The design beam spots here are about 2 microns in the vertical and 20 microns in the horizontal plane. The scanners presented a number of design challenges. In this paper we discuss the mechanical design of the scanner, and fabrication techniques of its ceramic wire support card which holds many 4 and 7 um carbon wires. Accurate motion of the wire during a scan is critical. In this paper we describe tests of stepper motors, gear combinations, and radiation hardened encoders needed to produce the required motion with a step resolution of 80 nanometers. Also presented here are the results of scattered radiation detector placement studies carried out to optimize the signal from the 4 micron wires. Finally, we present measurements from the scanner

  16. Beam Quality Preservation in the CERN PS-SPS Complex

    CERN Multimedia

    Arduini, Gianluigi

    2004-01-01

    The LHC will require beams of unprecedented transverse and longitudinal brightness. Their production imposes tight constraints on the emittance growth in each element of the LHC injector chain, namely the PS-SPS Accelerator Complex. The problems encountered at the different stages of the acceleration in the complex span a wide range of topics, such as injection matching, RF gymnastics, space charge, transverse and longitudinal single- and coupled-bunch instabilities, and electron cloud effects. The measurement techniques developed and applied to identify and study the various sources of emittance dilution to the high precision required for the LHC beams and the solutions found to control such phenomena are illustrated.

  17. Spherical proton emitters

    International Nuclear Information System (INIS)

    Berg, S.; Semmes, P.B.; Nazarewicz, W.

    1997-01-01

    Various theoretical approaches to proton emission from spherical nuclei are investigated, and it is found that all the methods employed give very similar results. The calculated decay widths are found to be qualitatively insensitive to the parameters of the proton-nucleus potential, i.e., changing the potential parameters over a fairly large range typically changes the decay width by no more than a factor of ∼3. Proton half-lives of observed heavy proton emitters are, in general, well reproduced by spherical calculations with the spectroscopic factors calculated in the independent quasiparticle approximation. The quantitative agreement with experimental data obtained in our study requires that the parameters of the proton-nucleus potential be chosen carefully. It also suggests that deformed proton emitters will provide invaluable spectroscopic information on the angular momentum decomposition of single-proton orbitals in deformed nuclei. copyright 1997 The American Physical Society

  18. 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

  19. Measurements of the sensitivity of radiochromic film using ion beams

    Science.gov (United States)

    Steidle, J. A.; Shortino, J. P.; Ellison, D. M.; Freeman, C. G.; Sangster, T. C.

    2013-10-01

    Radiochromic film (RCF) is used in several diagnostics as a dosimeter that chromatically responds to incident particles. This response depends on the fluence, energy, and species of the incident particles. A 1.7 MV tandem Pelletron accelerator is used to create a monoenergetic ion beam which is scattered off a thin gold target onto a strip of RCF. A surface barrier detector is positioned behind a small hole in the film to measure the ion fluence on the nearby film. Once the film develops, it is scanned to examine its optical density. A response curve is acquired by fitting a three parameter formula to optical density and dose. These calibration curves can be used to help determine incident doses in a variety of situations.

  20. An optimized Faraday cage design for electron beam current measurements

    International Nuclear Information System (INIS)

    Turner, J.N.; Hausner, G.G.; Parsons, D.F.

    1975-01-01

    A Faraday cage detector is described for measuring electron beam intensity for use with energies up to 1.2 Mev, with the present data taken at 100 keV. The design features a readily changeable limiting aperture and detector cup geometry, and a secondary electron suppression grid. The detection efficiency of the cage is shown to be limited only by primary backscatter through the detector solid angle of escape, which is optimized with respect to primary backscattered electrons and secondary electron escape. The geometry and stopping material of the detection cup are varied, and the results show that for maximum detection efficiency with carbon as the stopping mateiral, the solid angle of escape must be equal to or less than 0.05πsr. The experimental results are consistent within the +-2% accuracy of the detection electronics, and are not limited by the Faraday cage detection efficiency. (author)

  1. Spectral beam combining of a 980 nm tapered diode laser bar

    DEFF Research Database (Denmark)

    Vijayakumar, Deepak; Jensen, Ole Bjarlin; Ostendorf, Ralf

    2010-01-01

    We demonstrate spectral beam combining of a 980 nm tapered diode laser bar. The combined beam from 12 tapered emitters on the bar yielded an output power of 9.3 W at 30 A of operating current. An M2 value of 5.3 has been achieved along the slow axis. This value is close to that of a free running...... single tapered emitter on the bar at the same current level. The overall spectral beam combining efficiency was measured to be 63%....

  2. The new SLS beam size monitor, first results

    CERN Document Server

    Saa Hernandez, A; Rohrer, M; Schlott, V; Streun, A; Andersson, A; Breunlin, J

    2013-01-01

    An extremely small vertical beam size of 3.6 µm, corresponding to a vertical emittance of 0.9 pm, only about five times bigger than the quantum limit, has been achieved at the storage ring of the Swiss Light Source (SLS). The measurement was performed by means of a beam size monitor based on the imaging of the vertically polarized synchrotron radiation in the visible and UV spectral ranges. However, the resolution limit of the monitor was reached during the last measurement campaign and prevented further emittance minimization. In the context of the work package SLS Vertical Emittance Tuning of the TIARA collaboration, a new improved monitor was built. It provides larger magnification, an increase of resolution and enables two complementary methods of measurement: imaging and interferometry. In this paper we present the design, installation, commissioning, performance studies and first results obtained with the new monitor.

  3. Analytical Considerations for Reducing the Effective Emittance with Variable Dipole Field Strengths

    CERN Document Server

    Papaphilippou, Yannis

    2005-01-01

    The basic optics design scope in lepton rings is to match the sections in either side of the bending magnets in order to minimise the equilibrium emittance. A further important emittance reduction can be achieved by incorporating dipoles for which the deflecting field varies along the electron beam path in the magnet. The figure of merit for such lattices when used in a synchrotron light source is the minimization of the so-called effective emittance. The effective emittance is computed in the middle of the undulator straight section as the product of the rms size and divergence and therefore includes contributions from the betatron emittance and from the electron energy spread. In this paper, analytical formulas are obtained for the minimum betatron and effective emittance in arbitrary dipole fields and the associated optics function at the dipole entrance. Examples are given for specific dipole field functions and their properties with respect to the effective emittance minimisation. Finally, the effective ...

  4. LHC Damper Beam commissioning in 2010

    CERN Document Server

    Höfle, W; Schokker, M; Valuch, D

    2011-01-01

    The LHC transverse dampers were commissioned in 2010 with beam and their use at injection energy of 450 GeV, during the ramp and in collisions at 3.5 TeV for Physics has become part of the standard operations pro- cedure. The system proved important to limit emittance blow-up at injection and to maintain smaller than nominal emittances throughout the accelerating cycle. We describe the commissioning of the system step-by-step as done in 2010 and summarize its performance as achieved for pro- ton as well as ion beams in 2010. Although its principle function is to keep transverse oscillations under control, the system has also been used as an exciter for abort gap clean- ing and tune measurement. The dedicated beam position measurement system with its low noise properties provides additional possibilities for diagnostics.

  5. Development and Applications of Residual Stress Measurements Using Neutron Beams

    International Nuclear Information System (INIS)

    2014-01-01

    The deep penetration and selective absorption of neutrons make them a powerful tool for the non-destructive testing of large samples of material or large objects. Residual stress that is formed in a material during manufacturing, welding, utilization or repair can be measured by means of neutron diffraction. In fact, neutron diffraction is the only non-destructive testing method which can facilitate three dimensional mapping of residual stress in a bulk component. Stress measurement using neutron beams is a technique that enables this kind of high quality non-destructive investigation, and provides insight into the material strain and stress state deep within engineering components and structures under various conditions representative of those which might be experienced in service. Such studies are of importance to improve the quality of industrial components in production and to optimize design criteria in applications. Anisotropies in macroscopic properties such as thermal and electrical conductivities, for instance of fuel elements, and mechanical properties of materials depend on the textures developed during their preparation or thermal treatment. Such textures also can be studied using neutron diffraction techniques. There is currently substantial scientific and industrial demand for high quality non-destructive residual stress measurements, and the continuing competitive drive to optimize performance and minimize weight in many applications indicates that this demand will continue to grow. As such, the neutron diffraction technique is an increasingly important tool for mechanical and materials engineering in the search for improved manufacturing processes to reduce stress and distortion. Considering this trend, and in accordance with its purpose of promoting the peaceful use of nuclear applications, in 2006-2009 the IAEA organized a Coordinated Research Project on the Development and Application of the Techniques of Residual Stress Measurements in Materials

  6. Activity measurements of the high-energy pure beta-emitters Sr-89 and Y-90 by the TDCR efficiency calculation technique

    CSIR Research Space (South Africa)

    Simpson, BRS

    2006-10-01

    Full Text Available The absolute activities of the pure beta-emitters Sr-89 and Y-90 have been determined by a direct method, namely the triple-to-double coincidence ratio (TDCR) efficiency calculation technique. This undertaking has extended further the number...

  7. Sources of Emittance in RF Photocathode Injectors

    Energy Technology Data Exchange (ETDEWEB)

    Dowell, David [SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2016-12-11

    Advances in electron beam technology have been central to creating the current generation of x-ray free electron lasers and ultra-fast electron microscopes. These once exotic devices have become essential tools for basic research and applied science. One important beam technology for both is the electron source which, for many of these instruments, is the photocathode RF gun. The invention of the photocathode gun and the concepts of emittance compensation and beam matching in the presence of space charge and RF forces have made these high-quality beams possible. Achieving even brighter beams requires a taking a finer resolution view of the electron dynamics near the cathode during photoemission and the initial acceleration of the beam. In addition, the high brightness beam is more sensitive to degradation by the optical aberrations of the gun’s RF and magnetic lenses. This paper discusses these topics including the beam properties due to fundamental photoemission physics, space charge effects close to the cathode, and optical distortions introduced by the RF and solenoid fields. Analytic relations for these phenomena are derived and compared with numerical simulations.

  8. Transverse beam profile reconstruction using synchrotron radiation interferometry

    Directory of Open Access Journals (Sweden)

    L. Torino

    2016-12-01

    Full Text Available Transverse beam size measurements in new generation of synchrotron light sources is a challenging task due to their characteristic small beam emittances and low couplings. Since the late 1990s, synchrotron radiation interferometry (SRI has been used in many accelerators to measure the beam size through the analysis of the spatial coherence of the synchrotron light. However, the standard SRI using a double-aperture system provides the beam size projection in a given direction. For this reason, the beam shape is not fully characterized because information about possible transverse beam tilts is not determined. In this report, we describe a technique to fully reconstruct the transverse beam profile based on a rotating double-pinhole mask, together with experimental results obtained at ALBA under different beam couplings. We also discuss how this method allows us to infer ultrasmall beam sizes in case of limitations of the standard SRI.

  9. Experimental results of the laserwire emittance scanner for LINAC4 at CERN

    CERN Document Server

    Hofmann, Thomas; Bosco, Alessio; Bravin, Enrico; Gibson, Stephen M.; Kruchinin, Konstantin O.; Raich, Uli; Roncarolo, Federico; Zocca, Francesca

    2016-01-01

    Within the framework of the LHC Injector Upgrade (LIU), the new LINAC4 is currently being commissioned to replace the existing LINAC2 proton source at CERN. After the expected completion at the end of 2016, the LINAC4 will accelerate H- ions to 160 MeV. To measure the transverse emittance of the H- beam, a method based on photo-detachment is proposed. This system will operate using a pulsed laser with light delivered via an optical fibre and subsequently focused through a thin slice of the H- beam. The laser photons have sufficient energy to detach the outer electron and create H0/e- pairs. In a downstream dipole, the created H0 particles are separated from the unstripped H- ions and their distribution is measured with a dedicated detector. By scanning the focused laser across the H- beam, the transverse emittance of the H- beam can be reconstructed. This paper will first discuss the concept, design and simulations of the laser

  10. Emittance growth in coast in the SPS

    CERN Document Server

    Alekou, A; Bartosik, H; Calaga, R

    2017-01-01

    The CERN SPS will be used as a test-bed for the LHCprototype crab-cavities, which will be installed and testedin the SPS in 2018. As the time available for experimen-tal beam dynamics studies with the crab cavities installedin the machine will be limited, a very good preparation isrequired in advance. One of the main concerns is the in-duced emittance growth, driven by phase jitter in the crabcavities. In this respect, several machine development (MD)studies were performed during the past years to quantifyand characterize the emittance evolution of proton beamsin coast in the SPS. In these proceedings, the experimentalobservations from past years are summarized and the MDstudies from 2016 are presented. Finally, a proposal for anexperimental program for 2017 is discussed.

  11. Computing Eigen-Emittances from Tracking Data

    Energy Technology Data Exchange (ETDEWEB)

    Alexahin, Y. [Fermilab

    2014-09-18

    In a strongly nonlinear system the particle distribution in the phase space may develop long tails which contribution to the covariance (sigma) matrix should be suppressed for a correct estimate of the beam emittance. A method is offered based on Gaussian approximation of the original particle distribution in the phase space (Klimontovich distribution) which leads to an equation for the sigma matrix which provides efficient suppression of the tails and cannot be obtained by introducing weights. This equation is easily solved by iterations in the multi-dimensional case. It is also shown how the eigen-emittances and coupled optics functions can be retrieved from the sigma matrix in a strongly coupled system. Finally, the developed algorithm is applied to 6D ionization cooling of muons in HFOFO channel.

  12. Prototype system for phase advance measurements of LHC small beam oscillations

    CERN Document Server

    Olexa, J; Brezovic, Z; Gasior, M

    2013-01-01

    Magnet lattice parameters of the Large Hadron Collider (LHC) are measured by exciting beam transverse oscillations that allow measuring their phase advance using the beam position measurement (BPM) system. However, the BPM system requires millimetre oscillation amplitudes, with which nominal high intensity beams would cause large particle loss, dangerous for the LHC superconducting magnets. Therefore, such measurements cannot be done often, as they require special low intensity beams with important set-up time. After its first long shut-down the LHC will be equipped with new collimators with embedded BPMs, for which a new front-end electronics has been developed. Its main processing channels based on compensated diode detectors are designed for beam orbit measurement with sub-micrometre resolution. It is planned to extend this system by adding dedicated channels optimised for phase advance measurement, allowing continuous LHC optics measurement with much smaller beam excitation. This subsystem will be based o...

  13. Multi-beam synchronous measurement based on PSD phase detection using frequency-domain multiplexing

    Science.gov (United States)

    Duan, Ying; Qin, Lan; Xue, Lian; Xi, Feng; Mao, Jiubing

    2013-10-01

    According to the principle of centroid measurement, position-sensitive detectors (PSD) are commonly used for micro displacement detection. However, single-beam detection method cannot satisfy such tasks as multi-dimension position measurement, three dimension vision reconstruction, and robot precision positioning, which require synchronous measurement of multiple light beams. Consequently, we designed PSD phase detection method using frequency-domain multiplexing for synchronous detection of multiple modulated light beams. Compared to previous PSD amplitude detection method, the phase detection method using FDM has advantages of simplified measuring system, low cost, high capability of resistance to light interference as well as improved resolution. The feasibility of multi-beam synchronous measurement based on PSD phase detection using FDM was validated by multi-beam measuring experiments. The maximum non-linearity error of the multi-beam synchronous measurement is 6.62%.

  14. A system for measuring the energy spread of an accelerated beam

    International Nuclear Information System (INIS)

    Wilkerson, J.F.; Ludwig, E.J.; Clegg, T.B.; Anderson, R.E.

    1987-01-01

    A system has been implemented to monitor directly the energy spread of analyzed beams from a tandem electrostatic accelerator. The dispersion of a deflection magnet in the beam handling system is used to transform the energy distribution into a spatial distribution, which then is measured by electrostatically sweeping the spatially extended beam across a narrow slit. (orig.)

  15. Low Emittance Growth in a LEBT with Un-Neutralized Section

    Energy Technology Data Exchange (ETDEWEB)

    Prost, Lionel [Fermilab; Carneiro, Jean-Paul [Fermilab; Shemyakin, Alexander [Fermilab

    2016-06-01

    In a Low Energy Beam Transport line (LEBT), the emittance growth due to the beam's own space charge is typically suppressed by way of neutralization from either electrons or ions, which originate from ionization of the background gas. In cases where the beam is chopped, the neutralization pattern changes throughout the beginning of the pulse, causing the Twiss parameters to differ significantly from their steady state values, which, in turn, may result in beam losses downstream. For a modest beam perveance, there is an alternative solution, in which the beam is kept un-neutralized in the portion of the LEBT that contains the chopper. The emittance can be nearly preserved if the transition to the un-neutralized section occurs where the beam exhibits low transverse tails. This report discusses the experimental realization of such a scheme at Fermilab's PXIE, where low beam emittance dilution was demonstrated

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

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Y., E-mail: yjma@ciae.ac.cn; Cui, B.; Ma, R.; Tang, B.; Chen, L.; Huang, Q.; Jiang, W. [China Institute of Atomic Energy, Beijing 102413 (China)

    2014-02-15

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

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

    Science.gov (United States)

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

    2014-02-01

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

  18. Dielectric emitter in an injector of a linear induction electron accelerator

    International Nuclear Information System (INIS)

    Tomskikh, O.N.; Furman, Eh.G.

    1991-01-01

    Dielectric emitter in an injector of linear induction electron accelerator is decribed. Principle of operation of a new-type cathode - dielectric emitter - is based on preliminary accumulation of electron charge on the dielectric surface with their subsequent injection. Injector design of linear induction accelerator with dielectric emitter, providing for generation of beam current of 1.5 kA by charging voltage of 29 kV and accelerating voltage of 400 kV is described

  19. Design for a practical, low-emittance damping ring

    International Nuclear Information System (INIS)

    Krejcik, P.

    1988-01-01

    The luminosity requirements for future high-energy linear colliders calls for very low emittances in the two beams. These low emittances can be achieved with damping rings, but, in order to reach the design goal of a factor 10 improvement over present day machines, great care must be taken in their design. This paper emphasizes the need to address simultaneously all of the factors which limit the operational emittance in the ring. Particularly since in standard designs there is a conflict between different design parameters which makes it difficult to extrapolate such designs to very low emittances. The approach chosen here is to resolve such conflicts by separating their design solutions. Wigglers are used predominantly in zero-dispersion regions to achieve the desired damping rate, whereas in the arcs high dispersion insertions are made in regions of zero curvature to allow for easier chromaticity control

  20. Pulsed Electron Beam Spectroscopy for Temperature Measurements in Hypersonic Flows

    Science.gov (United States)

    2010-01-01

    Collisional Quenching Data ............................................ 26 C. Improvements to Pulsed E-Beam System...neutral g informati vibrationa The e-be flow m e Developm Shock T applicatio employs continuo mtorr are of an e-beam g the elect are acce through...the f irst two advantages result in improved signal/noise ratio over continuous e-beam systems and a shorter exposure time. The third advantage of a

  1. Beam Parameter Measurement and Control at the SNS Target

    CERN Document Server

    Plum, Michael; McManamy, Tom

    2005-01-01

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

  2. MD 2197: Experimental studies of Landau damping by means of Beam Transfer Function measurements in the presence of beam-beam interactions and diffusive mechanisms

    CERN Document Server

    Tambasco, Claudia; Barranco Garcia, Javier; Boccardi, Andrea; Buffat, Xavier; Bruce, Roderik; Gasior, Marek; Hostettler, Michi; Lefevre, Thibaut; Louro Alves, Diogo Miguel; Metral, Elias; Persson, Tobias Hakan Bjorn; Pieloni, Tatiana; Pojer, Mirko; Salvachua Ferrando, Belen Maria; Solfaroli Camillocci, Matteo; CERN. Geneva. ATS Department

    2018-01-01

    Beam Transfer Function (BTF) measurements are direct measurement of the stability diagrams that define the stability threshold of coherent beam instabilities driven by the impedance. At the LHC, some coherent instabilities at flat top energy are still not fully understood and the BTF measurements provide a method to experimentally probe the Landau damping of the proton beams. The BTF response is sensitive to the particle distribution changes and contain information about the transverse tune spread in the beams. The BTF system has been installed in the LHC in the 2015 in order to investigate the Landau damping at different stages of the operational cycle, machine configurations (different octupole currents, crossing angles, tunes etc...) and in presence of beam-beam excited resonances that may provoke diffusion mechanisms with a consequence change of Landau damping. Past MDs showed some difficulties for the reconstruction of the stability diagram from BTF measurements and several improvements on the BTF sy...

  3. Improved sample utilization in thermal ionization mass spectrometry isotope ratio measurements: refined development of porous ion emitters for nuclear forensic applications

    Energy Technology Data Exchange (ETDEWEB)

    Baruzzini, Matthew Louis [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-05-08

    The precise and accurate determination of isotopic composition in nuclear forensic samples is vital for assessing origin, intended use and process history. Thermal ionization mass spectrometry (TIMS) is widely accepted as the gold standard for high performance isotopic measurements and has long served as the workhorse in the isotopic ratio determination of nuclear materials. Nuclear forensic and safeguard specialists have relied heavily on such methods for both routine and atypical e orts. Despite widespread use, TIMS methods for the assay of actinide systems continue to be hindered by poor ionization e ciency, often less than tenths of a percent; the majority of a sample is not measured. This represents a growing challenge in addressing nextgeneration nuclear detection needs by limiting the ability to analyze ultratrace quantities of high priority elements that could potentially provide critical nuclear forensic signatures. Porous ion emitter (PIE) thermal ion sources were developed in response to the growing need for new TIMS ion source strategies for improved ionization e ciency, PIEs have proven to be simple to implement, straightforward approach to boosting ion yield. This work serves to expand the use of PIE techniques for the analysis of trace quantities of plutonium and americium. PIEs exhibited superior plutonium and americium ion yields when compared to direct lament loading and the resin bead technique, one of the most e cient methods for actinide analysis, at similar mass loading levels. Initial attempts at altering PIE composition for the analysis of plutonium proved to enhance sample utilization even further. Preliminary investigations of the instrumental fractionation behavior of plutonium and uranium analyzed via PIE methods were conducted. Data collected during these initial trial indicate that PIEs fractionate in a consistent, reproducible manner; a necessity for high precision isotope ratio measurements. Ultimately, PIEs methods were applied for

  4. The quantum measurement effect of interaction without interaction for an atomic beam

    Science.gov (United States)

    Huang, Yong-Yi

    When an atomic beam collectively and harmonically vibrates perpendicular to the wave vector of the beam, the number of atoms reaching the atomic detector will have a vibrant factor Δt / T if the measurement time interval Δt is shorter than the period T. This new quantum mechanical measurement effect for an atomic beam is called interaction without interaction: though the translational motion of the atomic beam does not interact with its collective and transverse harmonic vibration, the latter will have an effect on the measured number of atoms associated with the former. From the new measurement effect the classical harmonic vibration's period is evaluated. We give a clear physical picture and a satisfactory physical interpretation for the measurement effect based on the Copenhagen interpretation of quantum mechanics. We present an experimental proposal to verify this measurement effect for an ion beam instead of an atomic beam.

  5. LogAmp electronics and Optical Transmission for the new SPS Beam Position Measurement System

    CERN Document Server

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

    2013-01-01

    A new front-end board is under development for the CERN SPS Multi ORbit Position System (MOPOS). Based on logarithmic amplifiers, it measures the beam position over a large dynamic range of beam intensities and resolves the multi-batch structure of the SPS beams. Analogue data are digitized at 10 MS/s, packed in frames by an FPGA and on every turn sent to the readout board, via a 2.4 Gb/s optical transmission link. A first prototype has been successfully tested with several SPS beams. This paper presents an overall description of the system and its capabilities highlighted by the first beam measurements.

  6. Measurements of high-current electron beams from X pinches and wire array Z pinches

    International Nuclear Information System (INIS)

    Shelkovenko, T. A.; Pikuz, S. A.; Blesener, I. C.; McBride, R. D.; Bell, K. S.; Hammer, D. A.; Agafonov, A. V.; Romanova, V. M.; Mingaleev, A. R.

    2008-01-01

    Some issues concerning high-current electron beam transport from the X pinch cross point to the diagnostic system and measurements of the beam current by Faraday cups are discussed. Results of computer simulation of electron beam propagation from the pinch to the Faraday cup give limits for the measured current for beams having different energy spreads. The beam is partially neutralized as it propagates from the X pinch to a diagnostic system, but within a Faraday cup diagnostic, space charge effects can be very important. Experimental results show evidence of such effects.

  7. Monolithic multinozzle emitters for nanoelectrospray mass spectrometry

    Science.gov (United States)

    Wang, Daojing [Daly City, CA; Yang, Peidong [Kensington, CA; Kim, Woong [Seoul, KR; Fan, Rong [Pasadena, CA

    2011-09-20

    Novel and significantly simplified procedures for fabrication of fully integrated nanoelectrospray emitters have been described. For nanofabricated monolithic multinozzle emitters (NM.sup.2 emitters), a bottom up approach using silicon nanowires on a silicon sliver is used. For microfabricated monolithic multinozzle emitters (M.sup.3 emitters), a top down approach using MEMS techniques on silicon wafers is used. The emitters have performance comparable to that of commercially-available silica capillary emitters for nanoelectrospray mass spectrometry.

  8. Non-perturbative measurement of low-intensity charged particle beams

    Science.gov (United States)

    Fernandes, M.; Geithner, R.; Golm, J.; Neubert, R.; Schwickert, M.; Stöhlker, T.; Tan, J.; Welsch, C. P.

    2017-01-01

    Non-perturbative measurements of low-intensity charged particle beams are particularly challenging to beam diagnostics due to the low amplitude of the induced electromagnetic fields. In the low-energy antiproton decelerator (AD) and the future extra low energy antiproton rings at CERN, an absolute measurement of the beam intensity is essential to monitor the operation efficiency. Superconducting quantum interference device (SQUID) based cryogenic current comparators (CCC) have been used for measuring slow charged beams in the nA range, showing a very good current resolution. But these were unable to measure fast bunched beams, due to the slew-rate limitation of SQUID devices and presented a strong susceptibility to external perturbations. Here, we present a CCC system developed for the AD machine, which was optimised in terms of its current resolution, system stability, ability to cope with short bunched beams, and immunity to mechanical vibrations. This paper presents the monitor design and the first results from measurements with a low energy antiproton beam obtained in the AD in 2015. These are the first CCC beam current measurements ever performed in a synchrotron machine with both coasting and short bunched beams. It is shown that the system is able to stably measure the AD beam throughout the entire cycle, with a current resolution of 30 {nA}.

  9. A calorimeter-Faraday cup to measure energy content of ion beams

    International Nuclear Information System (INIS)

    Luzzi, G.

    1984-01-01

    A calorimeter-Faraday cup to measure energy content of ion beams is described. It uses an HP quartz thermometer having a 10 -40 C sensitivity; contact potential problems, arising when working with thermocouples, are so avoided. Calibration has been performed with a resistive filament and with an electron beam. The apparatus is profitable if the measured ion beams are constant in time. The measured sensitivity was 10 -40 C/10 -5 W. (author)

  10. Measuring penetration depth of electron beam welds. Final report

    International Nuclear Information System (INIS)

    Hill, J.W.; Collins, M.C.; Mentesana, C.P.; Watterson, C.E.

    1975-07-01

    The feasibility of evaluating electron beam welds using state-of-the-art techniques in the fields of holographic interferometry, micro-resistance measurements, and heat transfer was studied. The holographic study was aimed at evaluating weld defects by monitoring variations in weld strength under mechanical stress. The study, along with successful work at another facility, proved the feasibility of this approach for evaluating welds, but it did not assign any limitations to the technique. The micro-resistance study was aimed at evaluating weld defects by measuring the electrical resistance across the weld junction as a function of distance along the circumference. Experimentation showed this method, although sensitive, is limited by the same factors affecting other conventional nondestructive tests. Nevertheless, it was successful at distinguishing between various depths of penetration. It was also shown to be a sensitive thickness gage for thin-walled parts. The infrared study was aimed at evaluating weld defects by monitoring heat transfer through the weld under transient thermal conditions. Experimentation showed that this theoretically sound technique is not workable with the infrared equipment currently available at Bendix Kansas City. (U.S.)

  11. First Measurement of Beam-Recoil Observables Cx and Cz

    Energy Technology Data Exchange (ETDEWEB)

    R. Bradford; R.A. Schumacher; G. Adams; M.J. Amaryan; P. Ambrozewicz; E. Anciant; M. Anghinolfi; B. Asavapibhop; G. Asryan; G. Audit; H. Avakian; H. Bagdasaryan; N. Baillie; J.P. Ball; N.A. Baltzell; S. Barrow; V. Batourine; M. Battaglieri; K. Beard; I. Bedlinskiy; M. Bektasoglu; M. Bellis; N. Benmouna; B.L. Berman; N. Bianchi; A.S. Biselli; B.E. Bonner; S. Bouchigny; S. Boiarinov; D. Branford; W.J. Briscoe; W.K. Brooks; S. B¨ultmann; V.D. Burkert; C. Butuceanu; J.R. Calarco; S.L. Careccia; D.S. Carman; B. Carnahan; S. Chen; P.L. Cole; A. Coleman; P. Collins; P. Coltharp; D. Cords; † P. Corvisiero; D. Crabb; H. Crannell; V. Crede; J.P. Cummings; R. De Masi; E. De Sanctis; R. De Vita; P.V. Degtyarenko; H. Denizli; L. Dennis; A. Deur; K.V. Dharmawardane; R. Dickson; C. Djalali; G.E. Dodge; J. Donnelly; D. Doughty; P. Dragovitsch; M. Dugger; S. Dytman; O.P. Dzyubak; H. Egiyan; ; K.S. Egiyan; L. El Fassi; L. Elouadrhiri; A. Empl; P. Eugenio; R. Fatemi; G. Fedotov; G. Feldman; R.J. Feuerbach; T.A. Forest; H. Funsten; M. Garcon; G. Gavalian; ; G.P. Gilfoyle; K.L. Giovanetti; F.X. Girod; J.T. Goetz; A. Gonenc; R.W. Gothe; K.A. Griffioen; M. Guidal; M. Guillo; N. Guler; L. Guo; V. Gyurjyan; C. Hadjidakis; K. Hafidi; H. Hakobyan; R.S. Hakobyan; J. Hardie; D. Heddle; F.W. Hersman; K. Hicks; I. Hleiqawi; M. Holtrop; J. Hu; M. Huertas; C.E. Hyde-Wright; Y. Ilieva; D.G. Ireland; B.S. Ishkhanov; E.L. Isupov; M.M. Ito; D. Jenkins; H.S. Jo; K. Joo; H.G. Juengst; N. Kalantarians; J.D. Kellie; M. Khandaker; K.Y. Kim; K. Kim; W. Kim; A. Klein; F.J. Klein; M. Klusman; M. Kossov; L.H. Kramer; V. Kubarovsky; J. Kuhn; S.E. Kuhn; S.V. Kuleshov; J. Lachniet; J.M. Laget; J. Langheinrich; D. Lawrence; A.C.S. Lima; K. Livingston; H.Y. Lu; K. Lukashin; M. MacCormick; J.J. Manak; C. Marchand; N. Markov; S. McAleer; B. McKinnon; J.W.C. McNabb; B.A. Mecking; M.D. Mestayer; C.A. Meyer; T. Mibe; K. Mikhailov; M. Mirazita; R. Miskimen; V. Mokeev; K. Moriya; S.A. Morrow; M. Moteabbed; V. Muccifora; J. Mueller; G.S. Mutchler; P. Nadel-Turonski; J. Napolitano; R. Nasseripour; N. Natasha; S. Niccolai; G. Niculescu; I. Niculescu; B.B. Niczyporuk; M.R. Niroula; R.A. Niyazov; M. Nozar; G.V. O’Rielly; M. Osipenko; A.I. Ostrovidov; K. Park; E. Pasyuk; C. Paterson; S.A. Philips; J. Pierce; N. Pivnyuk; D. Pocanic; O. Pogorelko; E. Polli; I. Popa; S. Pozdniakov; B.M. Preedom; J.W. Price; Y. Prok; D. Protopopescu; L.M. Qin; B.P. Quinn; B.A. Raue; G. Riccardi; G. Ricco; M. Ripani; B.G. Ritchie; F. Ronchetti; G. Rosner; P. Rossi; D. Rowntree; P.D. Rubin; F. Sabatie; J. Salamanca; C. Salgado; J.P. Santoro; ; V. Sapunenko; V.S. Serov; A. Shafi; Y.G. Sharabian; J. Shaw; N.V. Shvedunov; S. Simionatto; A.V. Skabelin; E.S. Smith; L.C. Smith; D.I. Sober; D. Sokhan; M. Spraker; A. Stavinsky; S.S. Stepanyan; S. Stepanyan; B.E. Stokes; P. Stoler; I.I. Strakovsky; S. Strauch; M. Taiuti; S. Taylor; D.J. Tedeschi; U. Thoma; R. Thompson; A. Tkabladze; S. Tkachenko; L. Todor; C. Tur; M. Ungaro; M.F. Vineyard; A.V. Vlassov; K. Wang; D.P. Watts; L.B. Weinstein; H. Weller; D.P. Weygand; M. Williams; E. Wolin; M.H. Wood; A. Yegneswaran; J. Yun; L. Zana; J. Zhang; B. Zhao; and Z.W. Zhao

    2007-03-01

    Spin transfer from circularly polarized real photons to recoiling hyperons has been measured for the reactions $\\vec\\gamma + p \\to K^+ + \\vec\\Lambda$ and $\\vec\\gamma + p \\to K^+ + \\vec\\Sigma^0$. The data were obtained using the CLAS detector at Jefferson Lab for center-of-mass energies $W$ between 1.6 and 2.53 GeV, and for $-0.85<\\cos\\theta_{K^+}^{c.m.}< +0.95$. For the $\\Lambda$, the polarization transfer coefficient along the photon momentum axis, $C_z$, was found to be near unity for a wide range of energy and kaon production angles. The associated transverse polarization coefficient, $C_x$, is smaller than $C_z$ by a roughly constant difference of unity. Most significantly, the {\\it total} $\\Lambda$ polarization vector, including the induced polarization $P$, has magnitude consistent with unity at all measured energies and production angles when the beam is fully polarized. For the $\\Sigma^0$ this simple phenomenology does not hold. All existing hadrodynamic models are in poor agreement with these results.

  12. Vacuum Rabi spectra of a single quantum emitter.

    Science.gov (United States)

    Ota, Yasutomo; Ohta, Ryuichi; Kumagai, Naoto; Iwamoto, Satoshi; Arakawa, Yasuhiko

    2015-04-10

    We report the observation of the vacuum Rabi splitting of a single quantum emitter by measuring its direct spontaneous emission into free space. We use a semiconductor quantum dot inside a photonic crystal nanocavity, in conjunction with an appropriate cavity design and filtering with a polarizer and an aperture, enabling the extraction of the inherently weak emitter's signal. The emitter's vacuum Rabi spectra exhibit clear differences from those measured by detecting the cavity photon leakage. Moreover, we observe an asymmetric vacuum Rabi spectrum induced by interference between the emitter and cavity detection channels. Our observations lay the groundwork for accessing various cavity quantum electrodynamics phenomena that manifest themselves only in the emitter's direct spontaneous emission.

  13. Design of measurement equipment for high power laser beam shapes

    DEFF Research Database (Denmark)

    Hansen, K. S.; Olsen, F. O.; Kristiansen, Morten

    2013-01-01

    -chip implemented in a camera system. Most available CCD-based systems do however suffer from a low maximum intensity threshold. Therefore attenuation is needed. This paper describes the construction of such a beam analysing system where beam patterns produced by single mode fiber laser on a diffractic optical...

  14. Generating and measuring non-diffracting vector Bessel beams

    CSIR Research Space (South Africa)

    Dudley, Angela L

    2014-03-01

    Full Text Available We demonstrate how to create non-diffracting vector Bessel beams by implementing a spatial light modulator (SLM) to generate scalar Bessel beams which are then converted into vector fields by the use of an azimuthally-varying birefringent plate...

  15. Movement of Irrigation Water in Soil from a Surface Emitter

    Directory of Open Access Journals (Sweden)

    Ibrahim Abbas Dawood

    2016-09-01

    Full Text Available rickle irrigation is one of the most conservative irrigation techniques since it implies supplying water directly on the soil through emitters. Emitters dissipate energy of water at the end of the trickle irrigation system and provide water at emission points. The area wetted by an emitter depends upon the discharge of emitter, soil texture, initial soil water content, and soil permeability. The objectives of this research were to predict water distribution profiles through different soils for different conditions and quantify the distribution profiles in terms of main characteristics of soil and emitter. The wetting patterns were simulated at the end of each hour for a total time of application of 12 hrs, emitter discharges of 0.5, 0.75, 1, 2, 3, 4, and 5 lph, and five initial volumetric soil water contents. Simulation of water flow from a single surface emitter was carried out by using the numerically-based software Hydrus-2D/3D, Version 2.04. Two approaches were used in developing formulas to predict the domains of the wetted pattern. In order to verify the results obtained by implementing the software Hydrus-2D/3D a field experiment was conducted to measure the wetted diameter and compare measured values with simulated ones. The results of the research showed that the developed formulas to express the wetted diameter and depth in terms of emitter discharge, time of application, and initial soil water content are very general and can be used with very good accuracy.

  16. Flat beams in the SLC

    International Nuclear Information System (INIS)

    Adolphsen, C.; Barklow, T.; Burke, D.; Decker, F.J.; Emma, P.; Hildreth, M.; Himel, T.; Krejcik, P.; Limberg, T.; Minty, M.

    1993-01-01

    The Stanford Linear Collider was designed to operate with round beams; horizontal and vertical emittance made equal in the damping rings. The main motivation was to facilitate the optical matching through beam lines with strong coupling elements like the solenoid spin rotator magnets and the SLC arcs. Tests in 1992 showed that open-quote flat close-quote beams with a vertical to horizontal emittance ratio of around 1/10 can be successfully delivered to the end of the linac. Techniques developed to measure and control the coupling of the SLC arcs allow These beams to be transported to the Interaction Point (IP). Before flat beams could be used for collisions with polarized electrons, a new method of rotating the electron spin orientation with vertical arc orbit bumps had to be developed. Early in the 1993 run, the SLC was switched to open-quote flat close-quote beam operation. Within a short time the peak luminosity of the previous running cycle was reached and then surpassed. The average daily luminosity is now a factor of about two higher than the best achieved last year. In the following the authors present an overview of the problems encountered and their solutions for different parts of the SLC

  17. Simulated Measurements of Cooling in Muon Ionization Cooling Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Mohayai, Tanaz [IIT, Chicago; Rogers, Chris [Rutherford; Snopok, Pavel [Fermilab

    2016-06-01

    Cooled muon beams set the basis for the exploration of physics of flavour at a Neutrino Factory and for multi-TeV collisions at a Muon Collider. The international Muon Ionization Cooling Experiment (MICE) measures beam emittance before and after an ionization cooling cell and aims to demonstrate emittance reduction in muon beams. In the current MICE Step IV configuration, the MICE muon beam passes through low-Z absorber material for reducing its transverse emittance through ionization energy loss. Two scintillating fiber tracking detectors, housed in spectrometer solenoid modules upstream and downstream of the absorber are used for reconstructing position and momentum of individual muons for calculating transverse emittance reduction. However, due to existence of non-linear effects in beam optics, transverse emittance growth can be observed. Therefore, it is crucial to develop algorithms that are insensitive to this apparent emittance growth. We describe a different figure of merit for measuring muon cooling which is the direct measurement of the phase space density.

  18. A polarization-insensitive plasmonic photoconductive terahertz emitter

    KAUST Repository

    Li, Xurong

    2017-11-16

    We present a polarization-insensitive plasmonic photoconductive terahertz emitter that uses a two-dimensional array of nanoscale cross-shaped apertures as the plasmonic contact electrodes. The geometry of the cross-shaped apertures is set to maximize optical pump absorption in close proximity to the contact electrodes. The two-dimensional symmetry of the cross-shaped apertures offers a polarization-insensitive interaction between the plasmonic contact electrodes and optical pump beam. We experimentally demonstrate a polarization-insensitive terahertz radiation from the presented emitter in response to a femtosecond optical pump beam and similar terahertz radiation powers compared to previously demonstrated polarization-sensitive photoconductive emitters with plasmonic contact electrode gratings at the optimum optical pump polarization.

  19. Transverse emittance studies of an induction accelerator of heavy ions

    International Nuclear Information System (INIS)

    Garvey, T.; Eylon, S.; Fessenden, T.J.; Hahn, K.; Henestroza, E.

    1991-01-01

    Current amplification of heavy ion beams is an integral feature of the induction linac approach to heavy ion fusion. As part of the Heavy Ion Fusion Accelerator Research program at LBL the authors have been studying the evolution of the transverse emittance of ion beams while they are undergoing current amplification, achieved by longitudinal bunch compression and acceleration. Experiments are conducted on MBE-4, a four beam Cs + induction linac. The space-charge dominated beams of MBE-4 are focused by electrostatic quadrupoles while they are accelerated from nominally 200 keV up to ∼ 1 MEV by 24 accelerating gaps. Initially the beams have currents of typically 4 mA to 10 mA per beam. Early experimental results showed a growth of the normalized emittance by a factor of 2 while the beam current was amplified by up to 9 times its initial value. The authors will discuss the results of recent experiments in which a mild bunch length compression rate, more typical of that required by a fusion driver, has shown that the normalized emittance can be maintained at its injection value (0.03 mm-mr) during acceleration

  20. Observation of an optical vortex beam from a helical undulator in the XUV region.

    Science.gov (United States)

    Kaneyasu, Tatsuo; Hikosaka, Yasumasa; Fujimoto, Masaki; Iwayama, Hiroshi; Hosaka, Masahito; Shigemasa, Eiji; Katoh, Masahiro

    2017-09-01

    The observation of an optical vortex beam at 60 nm wavelength, produced as the second-harmonic radiation from a helical undulator, is reported. The helical wavefront of the optical vortex beam was verified by measuring the interference pattern between the vortex beam from a helical undulator and a normal beam from another undulator. Although the interference patterns were slightly blurred owing to the relatively large electron beam emittance, it was possible to observe the interference features thanks to the helical wavefront of the vortex beam. The experimental results were well reproduced by simulation.