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Sample records for beam emittance

  1. Beam emittance and beam disruption

    International Nuclear Information System (INIS)

    Beam disruption during the collision of intense relativistic bunches has been studied by R. Hollebeek. In the case of oppositely charged bunches, focussing effects occur causing a decrease in the effective bunch cross section, and thereby an increase of luminosity by an enhancement factor H. The term disruption derives from the fact that the beam emittance changes markedly during the collision. 1 ref., 1 fig., 1 tab

  2. Beam phase space and emittance

    International Nuclear Information System (INIS)

    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

  3. Beam emittance measurements in RHIC

    Energy Technology Data Exchange (ETDEWEB)

    Zelenski,A.; Bazilevsky, A.; Bunce, G.; Gill, R.; Huang, H.; Makdisi, Y.; Morozov, B.; Nemesure, S.; Russo, t.; Steski, D.; Sivertz, M.

    2009-05-04

    The RHIC proton polarimeters can operate in scanning mode, giving polarization profiles and transverse beam intensity profile (beam emittance) measurements. The polarimeters function as wire scanners, providing a very good signal/noise ratio and high counting rate. This allows accurate bunch-by-bunch emittance measurements during fast target sweeps (<1 s) through the beam. Very thin carbon strip targets make these measurements practically non-destructive. Bunch by bunch emittance measurements are a powerful tool for machine set-up; in RHIC, individual proton beam transverse emittances can only be measured by CNI polarimeter scans. We discuss the consistency of these measurements with Ionization Profile Monitors (IPMs) and vernier scan luminosity measurements. Absolute accuracy limitations and cross-calibration of different techniques are also discussed.

  4. Beam phase space and emittance

    International Nuclear Information System (INIS)

    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

  5. Beam emittance measurements at Fermilab

    Energy Technology Data Exchange (ETDEWEB)

    Wendt, Manfred; Eddy, Nathan; Hu, Martin; Scarpine, Victor; Syphers, Mike; Tassotto, Gianni; Thurman-Keup, Randy; Yang, Ming-Jen; Zagel, James; /Fermilab

    2008-01-01

    We give short overview of various beam emittance measurement methods, currently applied at different machine locations for the Run II collider physics program at Fermilab. All these methods are based on beam profile measurements, and we give some examples of the related instrumentation techniques. At the end we introduce a multi-megawatt proton source project, currently under investigation at Fermilab, with respect to the beam instrumentation challenges.

  6. The preservation of low emittance flat beams

    International Nuclear Information System (INIS)

    Many future linear collider designs require beams with very small transverse emittances and large emittance ratios εx much-gt εy. In this paper, we will discuss issues associated with the preservation of these small emittances during the acceleration of the beams. The primary sources of transverse emittance dilution in a high energy linear accelerator are the transverse wakefields, the dispersive errors, RF deflections, and betatron coupling. We will discuss the estimation of these effects and the calculation of tolerances that will limit the emittance dilution with a high degree of confidence. Since the six-dimensional emittance is conserved and only the projected emittances are increased, these dilutions can be corrected if the beam has not filamented (phase mixed). We discuss methods of correcting the dilutions and easing the tolerances with beam-based alignment and steering techniques, and non-local trajectory bumps. Finally, we discuss another important source of luminosity degradation, namely, pulse-to-pulse jitter

  7. Low Emittance Electron Beam Studies

    Energy Technology Data Exchange (ETDEWEB)

    Tikhoplav, Rodion

    2006-04-01

    We have studied the properties of a low emittance electron beam produced by laser pulses incident onto an rf gun photocathode. The experiments were carried out at the A0 photoinjector at Fermilab. Such beam studies are necessary for fixing the design of new Linear Colliders as well as for the development of Free Electron Lasers. An overview of the A0 photoinjector is given in Chapter 1. In Chapter 2 we describe the A0 photoinjector laser system. A stable laser system is imperative for reliable photoinjector operation. After the recent upgrade, we have been able to reach a new level of stability in the pulse-to-pulse fluctuations of the pulse amplitude, and of the temporal and transverse profiles. In Chapter 3 we present a study of transverse emittance versus the shape of the photo-cathode drive-laser pulse. For that purpose a special temporal profile laser shaping device called a pulse-stacker was developed. In Chapter 4 we discuss longitudinal beam dynamics studies using a two macro-particle bunch; this technique is helpful in analyzing pulse compression in the magnetic chicane, as well as velocity bunching effects in the rf-gun and the 9-cell accelerating cavity. In Chapter 5 we introduce a proposal for laser acceleration of electrons. We have developed a laser functioning on the TEM*{sub 01} mode, a mode with a longitudinal electric field component which is suitable for such a process. Using this technique at energies above 40 MeV, one would be able to observe laser-based acceleration.

  8. Measuring emittance using beam position monitors

    International Nuclear Information System (INIS)

    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

  9. Emittance in particle and radiation beam techniques

    International Nuclear Information System (INIS)

    The author discusses the important and diverse role of the phase space area - the emittance - in the advanced techniques involving interaction of particle and radiation beams. For undulator radiation from unbunched beams, the radiation phase space is diluted from the coherent phase space of the single electron radiation. When the undulator radiation is used as a light source, it is important to minimize the dilution by decreasing the beam emittance and matching the phase space distributions of the particle and the radiation beams. For optical stochastic cooling, on the other hand, the phase space should be maximally mismatched for efficient cooling. In the case particles are bunched to a length much shorter than the radiation wavelength, the emittance appears as an intensity enhancement factor. In the operation of free electron lasers, the phase space matching becomes doubly important, once as the dilution factor in the initial stage of energy modulation and then as the radiation efficiency factor at the end where the beam is density modulated. The author then discusses some of the beam cooling techniques producing smaller emittances, especially the recent suggestions for relativistic heavy ions in storage rings or electron beams in linacs. These are based on the radiative cooling that occurs when particle beams backscatter powerful laser beams

  10. Phase focusing for finite emittance beams

    International Nuclear Information System (INIS)

    An accelerator is a prime example of a physical system in which a beam of particles absorbs energy continuously from externally imposed electromagnetic fields only by remaining in, or very close to synchronism with the fields. Traveling-wave amplifiers are another example. When the injected beam has finite emittance, deviations from exact synchronism can arise, usually limiting the ultimate energy exchange with the fields, and the ultimate emittance of an accelerated beam. A general theory is provided in this paper for a means of limiting deviations from exact synchronism. This can be achieved by providing a small space-varying detuning from synchronism for a particle near the center of the distribution, thus allowing otherwise nonsynchronous particles brief opportunities to enjoy synchronism, and thus to limit their excursions in phase. To illustrate, an example is given of two-stage cyclotron autoresonance acceleration of a finite emittance beam, with and without detuning in the first stage. Space-varying detuning is shown to provide phase focusing in the first stage, lower phase spread at the entrance of the second stage, and thus higher ultimate energy. copyright 1999 American Institute of Physics

  11. Phase focusing for finite emittance beams

    International Nuclear Information System (INIS)

    An accelerator is a prime example of a physical system in which a beam of particles absorbs energy continuously from externally imposed electromagnetic fields only by remaining in, or very close to synchronism with the fields. Traveling-wave amplifiers are another example. When the injected beam has finite emittance, deviations from exact synchronism can arise, usually limiting the ultimate energy exchange with the fields, and the ultimate emittance of an accelerated beam. A general theory is provided in this paper for a means of limiting deviations from exact synchronism. This can be achieved by providing a small space-varying detuning from synchronism for a particle near the center of the distribution, thus allowing otherwise nonsynchronous particles brief opportunities to enjoy synchronism, and thus to limit their excursions in phase. To illustrate, an example is given of two-stage cyclotron autoresonance acceleration of a finite emittance beam, with and without detuning in the first stage. Space-varying detuning is shown to provide phase focusing in the first stage, lower phase spread at the entrance of the second stage, and thus higher ultimate energy

  12. Emittance measurements of low-energy beam line at KVI

    NARCIS (Netherlands)

    Toprek, D; Formanoy, [No Value

    2006-01-01

    In this paper is represented the results of beam profile measurements of He-3(+) beam delivered from ECR ion source at KVI. The beam emittance is estimated by varying quadrupole method. The estimated values for the beam emittance at the different profile grid locations along the transport beam line

  13. Low emittance electron beam optics commissioning in Indus-2

    International Nuclear Information System (INIS)

    Currently Indus-2 is normally operated with beam emittance of 85 nmrad at 2.0 GeV. In order to reduce the beam emittance to half of this value its dispersion function has been modified by properly choosing the quadrupoles strengths of the lattice. At this low beam emittance optics dynamic aperture reduces and may not be sufficient for beam injection thus a procedure has been evolved and implemented to shift the beam emittance of stored beam at 2.0 GeV. (author)

  14. A General Slice Moment Decomposition of RMS Beam Emittance

    CERN Document Server

    Mitchell, Chad

    2015-01-01

    The square of the horizontal projected (rms) beam emittance is expressed as the sum of four nonnegative contributions, each described using the slice moments of the beam and possessing a natural interpretation in terms of the geometrical properties of the beam in the six-dimensional phase space. The mathematical formalism describing the relationships between projected beam quantities and slice beam quantities is reviewed. The results may be used to reconstruct the moments and emittances of the beam from the moments of its subpopulations, as well as to isolate and better understand a variety of slice and interslice dynamical contributions to the projected beam emittance growth.

  15. Spectral beam combining of multi-single emitters

    Science.gov (United States)

    Wang, Baohua; Guo, Weirong; Guo, Zhijie; Xu, Dan; Zhu, Jing; Zhang, Qiang; Yang, Thomas; Chen, Xiaohua

    2016-03-01

    Spectral beam combination expands the output power while keeps the beam quality of the combined beam almost the same as that of a single emitter. Spectral beam combination has been successfully achieved for high power fiber lasers, diode laser arrays and diode laser stacks. We have recently achieved the spectral beam combination of multiple single emitter diode lasers. Spatial beam combination and beam transformation are employed before beams from 25 single emitter diode lasers can be spectrally combined. An average output power about 220W, a spectral bandwidth less than 9 nm (95% energy), a beam quality similar to that of a single emitter and electro-optical conversion efficiency over 46% are achieved. In this paper, Rigorous Coupled Wave analysis is used to numerically evaluate the influence of emitter width, emitter pitch and focal length of transform lens on diffraction efficiency of the grating and spectral bandwidth. To assess the chance of catastrophic optical mirror damage (COMD), the optical power in the internal cavity of a free running emitter and the optical power in the grating external cavity of a wavelength locked emitter are theoretically analyzed. Advantages and disadvantages of spectral beam combination are concluded.

  16. Emittance Measurements for Beams Extracted from LECR3 Ion Source

    Institute of Scientific and Technical Information of China (English)

    CaoYun; ZhaoHongwei; MaLei; ZhangZimin

    2003-01-01

    High quality ion beams are required by IMP cyclotron and atomic physics research, so it is important to research and measure beam emitt ance of ECR ion source. Intense beams extracted from ECR ion source usually have low energy, so it is suitable to use Electric-Sweep Scanner to measure the emittance. This kind of measurement is popularly used at ECR ion source, and it has some prominent merits such as high accuracy, very short time of data processing and easy expressing of the emittance pattern. So we designed and built this emittance scanner to measure emittance of the ion beams produced by LECR3 ion source. The structure of the ESS is shown in Fig.l, and the photo of the ESS is shown in Fig.2.

  17. Beam emittance reduction during operation of Indus-2

    Science.gov (United States)

    Fakhri, Ali Akbar; Kant, Pradeep; Ghodke, A. D.; Singh, Gurnam

    2015-11-01

    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.

  18. Beam emittance reduction during operation of Indus-2.

    Science.gov (United States)

    Fakhri, Ali Akbar; Kant, Pradeep; Ghodke, A D; Singh, Gurnam

    2015-11-01

    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. PMID:26628127

  19. 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.

  20. Beam emittance reduction during operation of Indus-2

    International Nuclear Information System (INIS)

    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

  1. Effect of beam emittance on self-modulation of long beams in plasma wakefield accelerators

    CERN Document Server

    Lotov, K V

    2015-01-01

    The initial beam emittance determines the maximum wakefield amplitude that can be reached as a result of beam self-modulation in the plasma. The wakefield excited by the fully self-modulated beam decreases linearly with the increase of the beam emittance. There is a value of initial emittance beyond which the self-modulation does not develop even if the instability is initiated by a strong seed perturbation. The emittance scale at which the wakefield is twice suppressed with respect to the zero-emittance case (the so called critical emittance) is determined by inability of the excited wave to confine beam particles radially and is related to beam and plasma parameters by a simple formula. The effect of beam emittance can be observed in several discussed self-modulation experiments.

  2. Scaled, circular-emitter Penning SPS for intense H- beams

    International Nuclear Information System (INIS)

    The Los Alamos versions of the Penning Surface-Plasma Source (SPS) routinely generate H- ion beams with pulsed currents over 100 mA. However, these sources employ geometries that result in the extraction of slit beams (0.5 x 10 mm2). Our modeling with the SNOW code indicates that the beam from a 5.4-mm-diam circular emitter will have lower emittance and divergence for transport to and injection into our radio-frequency quadrupole (RFQ) accelerator. This paper describes a newly constructed Penning SPS that has most of its discharge chamber dimensions scaled up by a factor of 4 to accommodate this circular emitter

  3. Beam Emittance Measurement for PLS-II Linac

    CERN Document Server

    Lee, Byung-Joon; Park, Chong do; Chunjarean, SomJai; Kim, Changbum

    2016-01-01

    The PLS-II has a 100 MeV pre-injector for the 3 GeV Linac. A thermionic gun produces electron charge of 200 pC with a bunch duration of 500 ps by a 250 ps triggering pulser. At the pre-injector, one of the most important beam parameters to identify the beam quality is a transverse emittance of electron bunches. Therefore we measure the beam emittance and twiss functions at 100 MeV in order to match the beam optics to beam transport line and go through it to the storage ring. To get the transverse emittance measurement, well-known technique, quadrupole scan, is used at the pre-injector. The emittance were 0.591 mm-mrad in horizontal and 0.774 mm-mrad in vertical direction.

  4. Innovative energy efficient low-voltage electron beam emitters

    International Nuclear Information System (INIS)

    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

  5. Transverse beam emittance measurement using quadrupole variation at KIRAMS-430

    Science.gov (United States)

    An, Dong Hyun; Hahn, Garam; Park, Chawon

    2015-02-01

    In order to produce a 430 MeV/u carbon ion (12 C 6+) beam for medical therapy, the Korea Institute of Radiological & Medical Sciences (KIRAMS) has carried out the development of a superconducting isochronous cyclotron, the KIRAMS-430. At the extraction of the cyclotron, an Energy Selection System (ESS) is located to modulate the fixed beam energy and to drive the ion beam through High Energy Beam Transport (HEBT) into the treatment room. The beam emittance at the ion beamline is to be measured to provide information on designing a beam with high quality. The well-known quadrupole variation method was used to determine the feasibility of measuring the transverse beam emittance. The beam size measured at the beam profile monitor (BPM) is to be utilized and the transformation of beam by transfer matrix is to be applied being taken under various transport condition of varying quadrupole magnetic strength. Two different methods where beam optics are based on the linear matrix formalism and particle tracking with a 3-D magnetic field distribution obtained by using OPERA3D TOSCA, are applied to transport the beam. The fittings for the transformation parameters are used to estimate the transverse emittance and the twiss parameters at the entrance of the quadrupole in the ESS. Including several systematic studies, we conclude that within the uncertainty the estimated emittances are consistent with the ones calculated by using Monte Carlo simulations.

  6. Uncorrelated Energy Spread and Longitudinal Emittance of a Photoinjector Beam

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Z; Dowell, D.; Emma, P.; Limborg-Deprey, C.; Stupakov, G.; Wu, J.; /SLAC

    2005-05-25

    Longitudinal phase space properties of a photoinjector beam are important in many areas of high-brightness beam applications such as bunch compression, transverse-to-longitudinal emittance exchange, and high-gain free-electron lasers. In this paper, we discuss both the rf and the space charge contributions to the uncorrelated energy spread of the beam generated from a laser-driven rf gun. We compare analytical expressions for the uncorrelated energy spread and the longitudinal emittance with numerical simulations and recent experimental results.

  7. Limits to Electron Beam Emittance from Stochastic Coulomb Interactions

    International Nuclear Information System (INIS)

    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.

  8. 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.

  9. Multi-dimensional beam emittance and β-functions

    International Nuclear Information System (INIS)

    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

  10. Use of beam emittance measurements in matching problems

    International Nuclear Information System (INIS)

    The CERN new 50 MeV linac should operate with a computer-aided beam matching in which the transverse criteria are based on measured r.m.s. values of beam co-ordinates in phase space. The collected data, however, need to undergo an intermediate treatment before significant results can be obtained and then used in computations. Some examples from the experimental study programme are given and the role of automated beam emittance measurements in matching problems discussed. (author)

  11. Emittance preservation during bunch compression with a magnetized beam

    Science.gov (United States)

    Stratakis, Diktys

    2016-03-01

    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 in combining a finite solenoid field where the beam is generated with a special optics adapter. Numerical simulations of this new type of beam source show that the induced phase-space density growth from CSR 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.

  12. 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.

  13. Development of High Intensity Beam Emittance Measurement Unit

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    Three sets of High Intensity Beam Emittance Measurement Units (HIBEMUs) are being developed at Peking University. They are HIBEMU-2 (slit-wire type, one direction), HIBEMU-3 (Allison scanner type, one direction) and HIBEMU-4 (slit-wire type, two directions). For HIBEMU-2 and HIBEMU-3, more recent work has been done on software redesign in order to measure beam emittance and to draw phase diagram more efficiently and precisely. Software for control and data processing of them were developed in Labveiw environment, trying to improve calculation rationality and to offer user-friendly interface. Mechanical modification was also done for HIBEMU-3, mainly concentrating on the protection of Faraday cups from being overheated by the high intensity beam and also from interference of secondary electrons. This paper will also cover the mechanical structure as well as the software development of HIBEMU-4, which is a two-direction emittance scanner newly designed and manufactured for the high energy beam transport (HEBT) of Peking University Neutron Imaging FaciliTY (PKUNIFTY). At the end of this paper, comparison and analysis of the three HIBEMUs are given to draw forth better design of the future emittance measurement facility.

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

    Science.gov (United States)

    Krasilnikov, M.; Stephan, F.; Asova, G.; Grabosch, H.-J.; Groß, M.; Hakobyan, L.; Isaev, I.; Ivanisenko, Y.; Jachmann, L.; Khojoyan, M.; Klemz, G.; Köhler, W.; Mahgoub, M.; Malyutin, D.; Nozdrin, M.; Oppelt, A.; Otevrel, M.; Petrosyan, B.; Rimjaem, S.; Shapovalov, A.; Vashchenko, G.; Weidinger, S.; Wenndorff, R.; Flöttmann, K.; Hoffmann, M.; Lederer, S.; Schlarb, H.; Schreiber, S.; Templin, I.; Will, I.; Paramonov, V.; Richter, D.

    2012-10-01

    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 , Nucl. Instrum. Methods Phys. Res., Sect. A 671, 62 (2012)NIMAER0168-900210.1016/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.

  15. Ion beam emittance from an ECRIS

    Energy Technology Data Exchange (ETDEWEB)

    Spädtke, P., E-mail: p.spaedtke@gsi.de; Lang, R.; Mäder, J.; Maimone, F.; Schlei, B. R.; Tinschert, K. [Gesellschaft für Schwerionenforschung (GSI), Darmstadt (Germany); Biri, S.; Rácz, R. [MTA Atomki, Debrecen (Hungary)

    2016-02-15

    Simulation of ion beam extraction from an Electron Cyclotron Resonance Ion Source (ECRIS) is a fully 3 dimensional problem, even if the extraction geometry has cylindrical symmetry. Because of the strong magnetic flux density, not only the electrons are magnetized but also the Larmor radius of ions is much smaller than the geometrical dimension of the plasma chamber (Ø 64 × 179 mm). If we assume that the influence of collisions is small on the path of particles, we can do particle tracking through the plasma if the initial coordinates of particles are known. We generated starting coordinates of plasma ions by simulation of the plasma electrons, accelerated stochastically by the 14.5 GHz radio frequency power fed to the plasma. With that we were able to investigate the influence of different electron energies on the extracted beam. Using these assumptions, we can reproduce the experimental results obtained 10 years ago, where we monitored the beam profile with the help of viewing targets. Additionally, methods have been developed to investigate arbitrary 2D cuts of the 6D phase space. To this date, we are able to discuss full 4D information. Currently, we extend our analysis tool towards 5D and 6D, respectively.

  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. Influence of injection beam emittance on beam transmission efficiency in a cyclotron

    Energy Technology Data Exchange (ETDEWEB)

    Kurashima, Satoshi, E-mail: kurashima.satoshi@jaea.go.jp; Kashiwagi, Hirotsugu; Miyawaki, Nobumasa; Yoshida, Ken-Ichi; Okumura, Susumu [Takasaki Advanced Radiation Research Institute, Japan Atomic Energy Agency, 1233 Watanuki, Takasaki, Gunma 370-1292 (Japan)

    2014-02-15

    The JAEA AVF cyclotron accelerates various kinds of high-energy ion beams for research in biotechnology and materials science. Beam intensities of an ion species of the order of 10{sup −9}–10{sup −6} ampere are often required for various experiments performed sequentially over a day. To provide ion beams with sufficient intensity and stability, an operator has to retune an ion source in a short time. However, the beam intensity downstream of the cyclotron rarely increases in proportion to the intensity at the ion source. To understand the cause of this beam behavior, transmission efficiencies of a {sup 12}C{sup 5+} beam from an electron cyclotron resonance ion source to the cyclotron were measured for various conditions of the ion source. Moreover, a feasible region for acceleration in the emittance of the injection beam was clarified using a transverse-acceptance measuring system. We confirmed that the beam emittance and profile were changed depending on the condition of the ion source and that matching between the beam emittance and the acceptance of the cyclotron was degraded. However, after fine-tuning to improve the matching, beam intensity downstream of the cyclotron increased.

  18. A transverse emittance and acceptance measurement system in a low-energy beam transport line

    Energy Technology Data Exchange (ETDEWEB)

    Kashiwagi, H., E-mail: kashiwagi.hirotsugu@jaea.go.jp; Miyawaki, N.; Kurashima, S.; Okumura, S. [Department of Advanced Radiation Technology, Japan Atomic Energy Agency, 1233 Watanuki, Takasaki, Gunma 370-1292 (Japan)

    2014-02-15

    A transverse beam emittance and acceptance measurement system has been developed to visualize the relationship between the injected beam emittance and the acceptance of a cyclotron. The system is composed of a steering magnet, two pairs of slits to limit the horizontal and vertical phase-space, a beam intensity detector just behind the slits for the emittance measurement, and a beam intensity detector in the cyclotron for the acceptance measurement. The emittance is obtained by scanning the slits and measuring the beam intensity distribution. The acceptance is obtained by measuring the distribution of relative beam transmission by injecting small emittance beams at various positions in a transverse phase-space using the slits. In the acceptance measurement, the beam from an ion source is deflected to the defined region by the slits using the steering magnet so that measurable acceptance area covers a region outside the injection beam emittance. Measurement tests were carried out under the condition of accelerating a beam of {sup 16}O{sup 6+} from 50.2 keV to 160 MeV. The emittance of the injected beam and the acceptance for accelerating and transporting the beam to the entrance of the extraction deflector were successfully measured. The relationship between the emittance and acceptance is visualized by displaying the results in the same phase-plane.

  19. 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...

  20. Beam emittance investigation in high brightness injector using different driver laser profiles

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    Beam emittance plays an important role in any accelerator, and it is a main parameter to judge the performance of an accelerator. Emittance optimization is an indispensable part in conditioning and operation of the facility. For a laser-driven high brightness injector, different time structure of the laser pulse has different effects on transverse emittance. In order to compare Gaussian and flat-top laser pulse, systematic simulations of 500 pC have been done. From the simulation results, one can see that flat-top pulse laser will yield smaller minimal transverse beam size and transverse beam emittance than Gaussian pulse laser.

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

    International Nuclear Information System (INIS)

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

  2. Emittance growth in displaced, space-charge-dominated beams with energy spread

    International Nuclear Information System (INIS)

    Conversion of transverse energy associated with the coherent motion of displaced beams into thermal energy, and thus emittance growth, has been predicted theoretically by a number of authors. Here, the authors show, using 2-D particle-in-cell simulations, that emittance growth is inhibited for tune depressed beams, if the energy spread of the beam is not too large. Further, using a uniform density model to calculate the space charge field of the beam, they numerically determine the criteria for emittance growth as a function of tune depression, energy spread, and beam displacement over a wide range of parameters. A theoretical interpretation of their results is presented

  3. Space-charged-induced emittance growth in the transport of high-brightness electron beams

    International Nuclear Information System (INIS)

    The emittance induced by space charge in a drifting beam of finite length has been investigated, and a scaling law has been obtained from simple considerations of the different rates of expansion of different portions of the beam. The scaling law predicts the initial rate of emittance growth, before the beam shape has distorted significantly, and thus represents an upper bound on the rate of emittance increase. This scaling law has been substantiated by particle-in-cell simulation and the dependence on geometric factors evaluated for specific choices of the beam profile. For long, axially nonuniform beams, the geometric factors have been evaluated explicitly for Gaussian profiles, and other shapes

  4. Focusing of ion beam with limit emittance by accelerator tube of electrostatic accelerator

    International Nuclear Information System (INIS)

    Focusing of nonrelativistic ion beam with finite emittance by accelerator tube is considered. Analytical relation between positions of the entrance and exit crossovers as a function of the beam emittance and the accelerator tube parameters was obtained. The comparison of conditions providing crossover to crossover transformation and conditions of entrance crossover optical image forming was carried out. 10 refs.; 3 figs

  5. Experimental Proof of Adjustable Single-Knob Ion Beam Emittance Partitioning

    CERN Document Server

    Groening, L; Xiao, C; Dahl, L; Gerhard, P; Kester, O K; Mickat, S; Vormann, H; Vossberg, M; Chung, M

    2014-01-01

    The performance of accelerators profits from phase space tailoring by coupling of planes. The previously applied techniques swap the emittances among the three planes but the set of available emittances is fixed. In contrast to these emittance exchange scenarios the emittance transfer scenario presented here allows for arbitrarily changing the set of emittances as long as the product of the emittances is preserved. This letter is on the first experimental demonstration of transverse emittance transfer along an ion beam line. The amount of transfer is chosen by setting just one single magnetic field value. The envelope-functions (beta) and -slopes (alpha) of the finally uncorrelated and re-partitioned beam at the exit of the transfer line do not depend on the amount of transfer.

  6. Miniature electron beam column with a silicon micro field emitter

    International Nuclear Information System (INIS)

    Silicon micro field emitters (Si-MFEs) are expected to be promising as electron sources for their high brightness and ease in making arrayed microcolumns due to small physical size. We have developed a Si-MFE electron gun assembly that produces an electron beam of 1 keV. All components including the Si acceleration electrode are mounted on an integrated circuit (IC) package stem (TO-8) by anodic and eutectic bonding. A high brightness (75 μA/sr) and a long lifetime (>1000 h) have been observed. To overcome the intrinsic emission instability of Si-MFEs, we developed a simple feedback circuit which controls an extraction voltage. The source position shift and the aberration coefficient change caused by stabilization were evaluated analytically and found to be negligible due to the scaling law as applied to micron size. We confirmed that the total emission fluctuation could be stabilized to less than 1% by detecting the absorption current but also found that this detection should be done in the electron beam column to stabilize the probe current due to the instability of the emission angle. Using the Si-MFE electron gun along with a miniature electron beam column 5 cm in length, we evaluated the electron optical properties and succeeded in demonstrating a scanning electron microscope operation with a resolution less than 0.5 μm. copyright 1997 American Vacuum Society

  7. Intrinsic beam emittance of laser-accelerated electrons measured by x-ray spectroscopic imaging

    OpenAIRE

    G. Golovin; Banerjee, S.; Liu, C; Chen, S.; Zhang, J.; Zhao, B.; Zhang, P.; Veale, M.; Wilson, M.; P. Seller; Umstadter, D.

    2016-01-01

    The recent combination of ultra-intense lasers and laser-accelerated electron beams is enabling the development of a new generation of compact x-ray light sources, the coherence of which depends directly on electron beam emittance. Although the emittance of accelerated electron beams can be low, it can grow due to the effects of space charge during free-space propagation. Direct experimental measurement of this important property is complicated by micron-scale beam sizes, and the presence of ...

  8. Beam emittance reconstructions at the KFUPM 350 keV ion accelerator

    International Nuclear Information System (INIS)

    We successfully reconstructed the horizontal and vertical beam emittances of a 160 keV low-intensity deuteron ion beam from the Energy Research Laboratory's low intensity duoplasmatron deuteron ion source. Reconstructions were made from horizontal and vertical beam width measurements. These measurements were done using only one quadrupole triplet and a beam profile monitor situated towards the end of the 45 beam line of the 350 kV ion accelerator. The deuteron beam emittances were εh = 67 π mm-mrad and εv = 4π mm-mrad at 90% of the beam. (orig.)

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

    International Nuclear Information System (INIS)

    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.))

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

    CERN Document Server

    Balandin, V; Golubeva, N

    2014-01-01

    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 gu...

  11. 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.

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

    International Nuclear Information System (INIS)

    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/cm2 is ∼0.59 mm mrad. The present system is very simple, and it eliminates many complexities of the existing schemes. (author)

  13. Effect of strong solenoidal focusing on beam emittance of low-energy intense proton beam in the SARAF LEBT

    Science.gov (United States)

    Shor, A.; Weissman, L.

    2016-07-01

    Influence of strong solenoidal beam focusing on beam emittance was studied at the SARAF LEBT beam line using 5 mA 20 keV proton quasi-DC beams. The measurements show that within the experimental uncertainties, emittance does not change over the whole focusing range. Detailed beam dynamics simulations were performed to achieve better understanding of the experimental results. The experimental and simulation results are fully consistent with the assumption of nearly full space charge neutralization for the quasi-DC proton beam.

  14. Characterizing and Optimizing Photocathode Laser Distributions for Ultra-low Emittance Electron Beam Operations

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, F. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Bohler, D. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Ding, Y. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Gilevich, S. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Huang, Z. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Loos, H. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Ratner, D. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Vetter, S. [SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2015-12-07

    Photocathode RF gun has been widely used for generation of high-brightness electron beams for many different applications. We found that the drive laser distributions in such RF guns play important roles in minimizing the electron beam emittance. Characterizing the laser distributions with measurable parameters and optimizing beam emittance versus the laser distribution parameters in both spatial and temporal directions are highly desired for high-brightness electron beam operation. In this paper, we report systematic measurements and simulations of emittance dependence on the measurable parameters represented for spatial and temporal laser distributions at the photocathode RF gun systems of Linac Coherent Light Source. The tolerable parameter ranges for photocathode drive laser distributions in both directions are presented for ultra-low emittance beam operations.

  15. Time-Resolved Emittance Characterization of an Induction Linac Beam using Optical Transition Radiation

    International Nuclear Information System (INIS)

    An induction linac is used by Lawrence Livermore National Laboratory to perform radiographic testing at the Flash X-ray Radiography facility. Emittance characterization is important since x-ray spot size impacts the resolution of shadow-graphs. Due to the long pulse length, high current, and beam energy, emittance measurement using Optical Transition Radiation is an attractive alternative for reasons that will be described in the text. The utility of OTR-based emittance measurement has been well demonstrated for both RF and induction linacs. We describe the time-resolved emittance characterization of an induction linac electron beam. We have refined the optical collection system for the induction linac application, and have demonstrated a new technique for probing the divergence of a subset of the beam profile. The experimental apparatus, data reduction, and conclusions will be presented. Additionally, a new scheme for characterizing the correlation between beam divergence and spatial coordinates within the beam profile will be described

  16. Time-Resolved Emittance Characterization of an Induction Linac Beam using Optical Transition Radiation

    CERN Document Server

    Le Sage, G P

    2002-01-01

    An induction linac is used by Lawrence Livermore National Laboratory to perform radiographic testing at the Flash X-ray Radiography facility. Emittance characterization is important since x-ray spot size impacts the resolution of shadow-graphs. Due to the long pulse length, high current, and beam energy, emittance measurement using Optical Transition Radiation is an attractive alternative for reasons that will be described in the text. The utility of OTR-based emittance measurement has been well demonstrated for both RF and induction linacs. We describe the time-resolved emittance characterization of an induction linac electron beam. We have refined the optical collection system for the induction linac application, and have demonstrated a new technique for probing the divergence of a subset of the beam profile. The experimental apparatus, data reduction, and conclusions will be presented. Additionally, a new scheme for characterizing the correlation between beam divergence and spatial coordinates within the b...

  17. Demonstration of Cathode Emittance Dominated High Bunch Charge Beams in a DC gun-based Photoinjector

    CERN Document Server

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

    2015-01-01

    We present the results of transverse emittance and longitudinal current profile measurements of high bunch charge (greater than or equal to 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 emittance 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 (ERLs) and Free Electron Lasers (FELs).

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

    International Nuclear Information System (INIS)

    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

  19. Shaping the electron beams with submicrosecond pulse duration in sources and electron accelerators with plasma emitters

    CERN Document Server

    Gushenets, V I

    2001-01-01

    One studies the techniques in use to shape submicrosecond electron beams and the physical processes associated with extraction of electrons from plasma in plasma emitters. Plasma emitter base sources and accelerators enable to generate pulse beams with currents varying from tens of amperes up to 10 sup 3 A, with current densities up to several amperes per a square centimeter, with pulse duration constituting hundreds of nanoseconds and with high frequencies of repetition

  20. Transverse emittance blow-up from beam injection errors in synchrotrons with nonlinear feedback systems

    International Nuclear Information System (INIS)

    The problem of transverse emittance blow-up from beam injection errors in synchrotrons with nonlinear feedback systems is considered. The relative emittance growth is calculated for linear and nonlinear feedback transfer functions. Effects of an increase of the damping decrement of the beam coherent oscillations and of a decrease of the coherent transverse amplitude spread of different bunches in case of the damper with positive cubic term in the feedback transfer function are discussed

  1. H- beam emittance measurements for the penning and the asymmetric, grooved magnetron surface-plasma sources

    International Nuclear Information System (INIS)

    Beam-intensity and emittance measurements show that the H- beam from our Penning surface-plasma source (SPS) has twice the intensity and ten times the brightness of the H- beam from an asymmetric, grooved magnetron SPS. We deduce H- ion temperatures of 5 eV for the Penning SPS and 22 eV for the asymmetric, grooved magnetron

  2. Extremely low vertical-emittance beam in accelerator-test facility at KEK

    International Nuclear Information System (INIS)

    Electron beams with the lowest, normalized transverse emittance recorded so far were produced and confirmed in single-bunch-mode operation of the Accelerator Test Facility at KEK. We established a tuning method of the damping rings which achieves a small vertical dispersion and small x-y orbit coupling. The vertical emittance was less than 1 percent of the horizontal emittance. At the zero-intensity limit, the vertical normalized emittance was less than 2.8 x 10-8 rad m at beam energy 1.3 GeV. At high intensity, strong effects of intrabeam scattering were observed, which had been expected in view of the extremely high particle density due to the small transverse emittance

  3. Emittance measurements of high current heavy ion beams using a single shot pepperpot system

    International Nuclear Information System (INIS)

    The new 1.4 MeV/u high current injector for the Unilac successfully commissioned in 1999 is now accelerating heavy ions close to the calculated intensities. For example an 40Ar1+ beam with 8 emA allows to fill the GSI synchrotron to its inherent intensity limit. For emittance measurements of such intense beams a single shot pepperpot system has been developed. An overview of the hard- and software including mathematical algorithms is given. Results of emittance measurements at different intensities and energies are presented. The influence of stripping and related space charge effects on the emittance could be investigated

  4. High Precision Measurement of Muon Beam Emittance Reduction in MICE

    CERN Document Server

    Rogers, Chris

    2005-01-01

    Muon ionization cooling, an essential ingredient of a neutrino factory, will be demonstrated for the first time by the MICE experiment. The central part of MICE consists of a short section of a neutrino factory cooling channel and the emittance reduction achieved in this experiment is quite modest, 10% to 15%. In order to extrapolate the performance of a full cooling channel from these values, it is crucial for MICE to achieve an emittance measurement accuracy of 10

  5. On the focused beam parameters of an electron gun with a plasma emitter

    International Nuclear Information System (INIS)

    The report presents the measurement results of the focused beam brightness in the electron gun with plasma emitter. The beam brightness was approximately 1010 A·m-2·sr-1 under the beam power up to 4 kW and an electron energy of 60 keV at the focal distance of 0.5 m. Qualitative assessment of the beam parameters was performed by welding test pieces. The results describing the possibility in principle of using the guns with a plasma emitter in nonvacuum technological devices are presented

  6. On the focused beam parameters of an electron gun with a plasma emitter

    Science.gov (United States)

    Kornilov, S.; Rempe, N.; Beniyash, A.; Murray, N.

    2014-11-01

    The report presents the measurement results of the focused beam brightness in the electron gun with plasma emitter. The beam brightness was approximately 1010 A·m-2·sr-1 under the beam power up to 4 kW and an electron energy of 60 keV at the focal distance of 0.5 m. Qualitative assessment of the beam parameters was performed by welding test pieces. The results describing the possibility in principle of using the guns with a plasma emitter in nonvacuum technological devices are presented.

  7. Self-field-driven rms emittances of a field-photoemitted intense short relativistic electron beam

    International Nuclear Information System (INIS)

    The photoinjector is presently considered as the best source for those low-emittance, short relativistic electron beams that various applications require. For high-current beams, the emittance growth is dominated by the self-field effects, and essentially located near the photocathode. In this region the electrons are submitted to a very strong acceleration so that the self-field effects cannot be considered as space-charge ones: relativistic acceleration and retardation phenomena have to be taken into account. A systematic study of transverse, longitudinal and 3D r.m.s. emittances, as a function of beam parameters and RF field intensity is presented, by extending preliminary results on the r.m.s. transverse emittances. (author) 5 refs.; 7 figs

  8. Beam emittance measurements and simulations of injector line for radio frequency quadrupole.

    Science.gov (United States)

    Mathew, Jose V; Rao, S V L S; Pande, Rajni; Singh, P

    2015-07-01

    A 400 keV deuteron (D(+)) radio frequency quadrupole (RFQ) accelerator has been designed, built, and commissioned at the Bhabha Atomic Research Centre, India. A beam line has been developed for injecting deuterons into the 400 keV RFQ. This comprises of a RF plasma ion source and a low energy beam transport (LEBT) system, consisting of two solenoid magnets and two steerer magnets. The ion source is characterized in terms of transverse beam emittance. A slit-wire scanner based emittance measurement setup has been developed for the transverse emittance measurements of H(+) and D(+) beams. The measured emittance values are found to be well within the acceptance value for the RFQ. These measured emittance parameters are used to optimize the solenoid fields in LEBT to match the beam from the ion source to RFQ. TRACEWIN simulation code is used for the beam transport simulations. The simulations show 99% transmission of D(+) beam through the RFQ, while 95% transmission has been measured experimentally. PMID:26233371

  9. Emittance growth in displaced, space-charge-dominated beams with energy spread

    Energy Technology Data Exchange (ETDEWEB)

    Barnard, J.J.; Miller, J. (Lawrence Livermore National Lab., CA (United States)); Haber, I. (Naval Research Lab., Washington, DC (United States))

    1993-05-11

    Conversion of transverse energy associated with the coherent motion of displaced beams into thermal energy, and thus emittance growth, has been predicted theoretically by a number of authors. Here, they authors show, using 2-D particle-in-cell simulations, that emittance growth is inhibited for tune depressed beams, if the energy spread of the beam is not too large. Further, using a uniform density model to calculate the space charge field of the beam, they numerically determine the criteria for emittance growth as a function of tune depression, energy spread, and beam displacement over a wide range of parameters. A theoretical interpretation of the results is presented. This study is applicable to an inertial fusion reactor driven by a heavy ion accelerator.

  10. Emittance growth in displaced, space-charge-dominated beams with energy spread

    International Nuclear Information System (INIS)

    Conversion of transverse energy associated with the coherent motion of displaced beams into thermal energy, and thus emittance growth, has been predicted theoretically by a number of authors. Here, they authors show, using 2-D particle-in-cell simulations, that emittance growth is inhibited for tune depressed beams, if the energy spread of the beam is not too large. Further, using a uniform density model to calculate the space charge field of the beam, they numerically determine the criteria for emittance growth as a function of tune depression, energy spread, and beam displacement over a wide range of parameters. A theoretical interpretation of the results is presented. This study is applicable to an inertial fusion reactor driven by a heavy ion accelerator

  11. Emittance growth in displaced, space-charge-dominated beams with energy spread

    Science.gov (United States)

    Barnard, J. J.; Miller, J.; Haber, I.

    1993-05-01

    Conversion of transverse energy associated with the coherent motion of displaced beams into thermal energy, and thus emittance growth, has been predicted theoretically by a number of authors. Here, they authors show, using 2-D particle-in-cell simulations, that emittance growth is inhibited for tune depressed beams, if the energy spread of the beam is not too large. Further, using a uniform density model to calculate the space charge field of the beam, they numerically determine the criteria for emittance growth as a function of tune depression, energy spread, and beam displacement over a wide range of parameters. A theoretical interpretation of the results is presented. This study is applicable to an inertial fusion reactor driven by a heavy ion accelerator.

  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. Emittance growth due to radial density variations of an emittance-dominated electron beam in a channel with continuous acceleration and focusing

    International Nuclear Information System (INIS)

    Simulations have identified charge-density variations as driving the dominant emittance growth mechanism for high-current, low-emittance induction linacs using solenoidal focusing, once the beam enters the emittance-dominated regime. In this paper, we use the radial equation of motion, including the nonlinearities resulting from radial density variations, to understand this effect. Nonlinearities in the beam close-quote s radial motion while in a solenoid arise from the noncancellation of the effects from the diamagnetic axial magnetic field and the potential depression of the beam, if the beam density is nonuniform. Any initial density variation drives a logarithmic increase in additional higher-order density variations (through the differential betatron motion), and an emittance growth that scales logarithmically, or greater (even potentially faster than linear), with the axial distance along the accelerator. The growth rate depends on the beam current, the focusing force, and the accelerating gradient, and for typical machine parameters, the growth rate can be faster than linear with distance. The magnitude of the emittance growth depends critically on the matching of the beam from the injector to the beamline. This formalism leads to a criterion of how uniform the beam density has to be and how well the beam needs to be matched in order not to have an unacceptable emittance growth. copyright 1998 American Institute of Physics

  14. Development of a transverse beam emittance and Twiss parameters measurement system for transport line-1

    International Nuclear Information System (INIS)

    Beam Transport Line-1 (TL-1) in Indus Accelerator Complex at Raja Ramanna Centre for Advanced Technology (RRCAT), Indore is being used to transport 20 MeV, 30 mA beam from the injector Microton exit point to the Booster Synchrotron where energy of electron beam is raised from 20 MeV to 450 MeV for injection into Indus-1 storage ring and 550 MeV to Indus-2 storage ring. It is important to measure the transverse beam emittance and Twiss parameters at Microton beam exit point for beam optics optimization in the transport line and to judge the beam quality. A transverse emittance and Twiss parameters measurement system using quadrupole scan method has been developed and tested. The system uses the electron beam images from the existing scintillator based beam profile monitor installed in TL-1 for beam size measurement. We have developed MATLAB codes that can extract transverse beam size and estimate transverse beam emittance. This paper describes the measurement method, software and some initial results obtained using this system. (author)

  15. Design studies for minimization of beam emittance in the LEHIPA LEBT

    International Nuclear Information System (INIS)

    The main design criterion in the Low Energy Beam Transport (LEBT) system is to transport and match the beam from the ion source into the RFQ with minimum emittance growth and loss of beam current. The LEHIPA LEBT is required to match a 30 mA, 50 keV, CW proton beam from the ion source to the RFQ. At these energies, for such high currents, the space charge forces, which are due to the coulomb repulsion between the particles, are very strong. These forces are highly non-linear and can lead to rapid increase in emittance and beam size. The beam quality and transmission through the RFQ is very sensitive to the beam parameters at its input. Also beam quality degradation is initiated mainly in the low energy sections of the linacs and later manifests itself in the form of beam halos at high energies. So careful studies in matching the beam from the ion source to the RFQ is required for minimizing emittance growth. The beam from the ion source also contains other species like H2+ and H3+ . An important function of the LEBT is also to reject these fractions and prevent them from entering the RFQ. Based on these criterions, detailed beam dynamics simulations have been done to optimize the design of the LEHIPA LEBT which will be presented in this paper. (author)

  16. Report on specification of the electron beam parameter suitable for emittance measurements

    CERN Document Server

    Malka, V

    2009-01-01

    The all optical external injection scheme that we will use with two colliding laser pulses allows a way to stabilize the injection of electrons into the plasma wave, and to easily tune the energy of the output beam by changing the longitudinal position of the injection. The charge and relative energy spread are also controllable by tuning parameters such as the injection intensity and its polarization. We report here on the control of the e-beam parameters, on the e-beam parameters that will be used for the conception and design of the emittance meter and on the experimental arrangement on which emittance measurement experiments will be achieved.

  17. Measurement of H- beam emittance in axial injection channel of DC-72 cyclotron

    International Nuclear Information System (INIS)

    A method of measuring the ion beam transversal emittance in the axial injection channel of DC-72 cyclotron is given. It is based on the gradient method using the standard rotating wire scanner for measurement of the transversal ion beam dimensions. This method was worked out for ion beam currents up to 1000 μA and allows one to reconstruct emittance with an accuracy about 30%. The method takes into account the ion beam self-charge, which is essential. It is not always a success to obtain an axial-symmetric ion beam in experiments. Therefore, a new experimental data processing method of measuring the transversal emittance for a non-axial-symmetric ion beam was suggested. The formulae for determination of the RMS dispersions of the ion beam dimensions in the rotation coordinate system by signals from the scanner wire are given. The measurements of the RMS emittances εx,y were carried out in the test stand of the injection channel of DC-72 cyclotron with the H- ion beam current of 180 μA and kinetic energy of ions of 16.82 keV. The results of the experimental data processing are adduced

  18. GEANT4 simulations for beam emittance in a linear collider based on plasma wakefield acceleration

    International Nuclear Information System (INIS)

    Alternative acceleration technologies are currently under development for cost-effective, robust, compact, and efficient solutions. One such technology is plasma wakefield acceleration, driven by either a charged particle or laser beam. However, the potential issues must be studied in detail. In this paper, the emittance evolution of a witness beam through elastic scattering from gaseous media and under transverse focusing wakefields is studied

  19. Longitudinal emittance measurement of the 100 MeV proton beam

    International Nuclear Information System (INIS)

    The results of the longitudinal emittance measurements carried out at the exit of the DTL part (100 MeV) of the 600 MeV Moscow meson emittance is determined from the bunch length measurements carried out at the exit of the last DTL cavity for three different and well known values of the accelerating field amplitudes. A Bunch length is measured by means of the bunch shape monitor with the phase resolution better than 1 degree at the DTL rf frequency. The results of the emittance measurements are used for a beam longitudinal matching between the DTL and the DAW parts of the linac

  20. The super collider transverse feedback system for suppression of the emittance growth and beam instabilities

    International Nuclear Information System (INIS)

    A super collider transverse feedback system designed to suppress injection errors, emittance growth due to external noises, and beam instabilities is considered. It is supposed that the feedback system should consist of two circuits: an injection damper operating just after injection and a super damper. To damp the emittance growth, the superdamper has to operate with the ultimate decrement close to the revolution frequency. The physics of such a feedback system and its main limitations are discussed. 9 refs.; 21 figs.; 1 tab

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

    International Nuclear Information System (INIS)

    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. FARTECH, 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 analysis 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

  2. Design and characterization of a movable emittance meter for low-energy electron beams

    International Nuclear Information System (INIS)

    In order to characterize and optimize the beam emittance compensation scheme [L. Serafini and J. B. Rosenzweig, Phys. Rev. E 55, 7565 (1997)] of the Sorgente Pulsata Autoamplificata di Radiazione Coerente project [D. Alesini et al., Nucl. Instrum. Methods Phys. Res. A 507, 345 (2003)] high brightness preinjector a system to accurately measure the beam rms emittance evolution downstream of the rf gun has been developed. Since in a space charge dominated beam the quadrupole-scan method is not applicable, a movable emittance measurement device has been built based on the pepper-pot technique. The device consists of a double system of horizontal and vertical slit arrays and a downstream screen, all installed on a longitudinally movable support equipped with bellows and spanning the ≅1.2 m long drift space between gun and first accelerating section. The system allows the measuring of the beam rms emittance all along the spanned region so as to accurately reconstruct its evolution along the beam trajectory. More than a simple improvement over more conventional beam emittance measurement tools this device defines a new strategy for characterizing high performance photoinjectors as it allows a detailed analysis of the beam behavior over a section of the accelerator where crucial beam shaping takes place. Numerical simulations of the measurement, mainly based on PARMELA [J. Billen, PARMELA Report No. LA-UR 96-1835, 1996 (unpublished)], have been used to estimate the achievable accuracy and to optimize the experimental setup. Wake field effects induced by the beam propagation through the bellows have also been investigated with HOMDYN [M. Ferrario et al., LCLS Report No. SLAC-PUB 84000, 1999 (unpublished)]. A series of laboratory tests to evaluate its performance has been carried out at LNF in Frascati. The system was then moved to DESY Zeuthen and installed on the Photo Injector Test Facility PITZ, for further testing with beam. Design criteria and tests carried out to

  3. Beam profile and emittance measurement in the CUTE-FEL setup

    International Nuclear Information System (INIS)

    Measurement of the size and profile of the electron beam in the CUTE-FEL setup has been performed in order to quantify the beam parameters. Since the CUTE-FEL employs a high charge beam, an optimization of beam parameters was performed to minimize the phosphor and CCD camera saturation. Neutral Density (ND) filters were employed to avoid CCD camera saturation. Measurement of beam emittance has also been performed by the pepper-pot technique using a new diagnostic chamber fabricated and installed in the beamline for the purpose. This paper discusses these beam characterization experiments. (author)

  4. Experimental measurement of emittance growth in mismatched space-charge-dominated beams

    International Nuclear Information System (INIS)

    Using the Single Beam Transport Experiment (SBTE) at LBL, we have measured the emittance of a well-matched 4.6-mA beam of 122-keV Cs+ to be conserved from injection into through exit from an 80-lens segment of the AG focussing channel. We then mismatched the beam into the same channel such that the maximum (minimum) radius of the beam at the midplane between lenses was about 1.5 (0.5) times the former value. We caused mismatches in the envelope of the beam in both transverse dimensions (labeled a and b) in modes both symmetric (δa = δb) and antisymmetric (δa = -δb). We found the mismatch amplitude to decay during the beam transit through the channel for both modes of mismatch, although more so for the antisymmetric mode. We also found the emittance of the symmetrically mismatched beam to be the same as for the matched beam, while the emittance of the antisymmetrically mismatched beam grew by as much as a factor of four over that for the matched beam

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

    International Nuclear Information System (INIS)

    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

  6. Beam dynamics studies and emittance optimization in the CTF3 linac at CERN

    CERN Document Server

    Urschütz, Peter; Corsini, Roberto; Döbert, Steffen; Ferrari, Arnaud; Tecker, Frank

    2006-01-01

    Small transverse beam emittances and well-known lattice functions are crucial for the 30 GHz power production in the Power Extraction and Transfer Structure (PETS) and for the commissioning of the Delay Loop of the CLIC Test Facility 3 (CTF3). Following beam dynamics simulation results, two additional solenoids were installed in the CTF3 injector in order to improve the emittance. During the runs in 2005 and 2006, an intensive measurement campaign to determine Twiss parameters and beam sizes was launched. The results obtained by means of quadrupole scans for different modes of operation suggest emittances well below the nominal .n,rms = 100 ?Î?Êm and a good agreement with PARMELA simulations.

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

    International Nuclear Information System (INIS)

    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

  8. 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.

  9. Plasma studies and beam emittance measurements of 2.45 GHz microwave ion source at VECC

    International Nuclear Information System (INIS)

    A 2.45 GHz microwave ion source operating at VECC is able to produce a total beam current of ∼ 12 mA at a beam energy of 75 KeV with a microwave power of 400 W as described in. In order to optimize the performance of the ion source, we have conducted systematic studies with the variation of ion source gas flow rate, magnetic field, extraction voltage, suppressor voltage, microwave power etc. The total extracted beam current was recorded as a function of each of the earlier mentioned parameters. Moreover, we have studied the effect on extracted beam current and its transmission in the beam transport line due to dielectric and water introduction into the plasma chamber. In the best setting, we have found a total extracted beam current of 12.5 mA with a beam transmission of 70 %. Furthermore, we have also studied the extracted beam current and its transmission in the beam transport line using aluminum plasma chamber of different diameters. Finally, we have estimated the beam emittance by solenoid scan technique of a neutralized 75 KeV, 5 mA proton beam by measuring beam profile using a non-interceptive residual gas fluorescence monitor. The measured normalized rms emittance of the neutralized beam is 0.05 mm-mrad, which seems to be quite reasonable. (author)

  10. Emittance reconstruction from measured beam sizes in ATF2 and perspectives for ILC

    Science.gov (United States)

    Faus-Golfe, A.; Navarro, J.; Fuster Martinez, N.; Resta Lopez, J.; Giner Navarro, J.

    2016-05-01

    The projected emittance (2D) and the intrinsic emittance (4D) reconstruction method by using the beam size measurements at different locations is analyzed in order to study analytically the conditions of solvability of the systems of equations involved in this process. Some conditions are deduced and discussed, and general guidelines about the locations of the measurement stations have been obtained to avoid unphysical results. The special case of the multi-Optical Transition Radiation system (m-OTR), made of four measurement stations, in the Extraction Line (EXT) of Accelerator Test Facility 2 (ATF2) has been simulated in much detail and compared with measurements. Finally a feasibility study of a multi-station system for fast transverse beam size measurement, emittance reconstruction and coupling correction in the Ring to Main Linac (RTML) of International Linear Collider (ILC) Diagnostic sections of the RTML has been discussed in detail.

  11. Beam-target interaction and intrabeam scattering in the HESR ring. Emittance, momentum resolution and luminosity

    International Nuclear Information System (INIS)

    The beam-target interaction is studied with respect to the transverse and longitudinal emittance growth of the HESR antiproton beam. The transverse emittance growth caused by the small angle Coulomb scattering can be described analytically using the differential cross section of the Coulomb interaction. Similarly, the longitudinal emittance growth caused by the energy loss of the beam can be calculated using the differential cross section of the energy-loss distribution. It is shown that particles with energy losses near the maximum energy loss in a head-on collision with a target electron are lost due to momentum acceptance of the HESR ring. Taking a relative momentum acceptance of about 1 x 10-3 into account yields an order of magnitude smaller growth rate of the mean square momentum deviation. The necessary cooling rates for the High Resolution mode and the High Luminosity mode are deduced assuming that the beam-target interaction is the dominant beam heating process. For comparison the effects of intrabeam scattering are estimated. For electron and stochastic cooling, analytic expressions are quoted in order to evaluate the momentum resolution and cooling rate. The potentialities of electron and stochastic cooling are discussed with respect to the achievable momentum resolution and beam-target overlap. Beam loss rates and average luminosities are evaluated taking the total hadronic cross section, the restricted momentum acceptance of the HESR ring, the large angle Coulomb scattering and the Touschek effect into account. (orig.)

  12. Beam-target interaction and intrabeam scattering in the HESR ring. Emittance, momentum resolution and luminosity

    Energy Technology Data Exchange (ETDEWEB)

    Hinterberger, F. [Bonn Univ. (Germany). Inst. fuer Strahlen- und Kernphysik

    2006-02-15

    The beam-target interaction is studied with respect to the transverse and longitudinal emittance growth of the HESR antiproton beam. The transverse emittance growth caused by the small angle Coulomb scattering can be described analytically using the differential cross section of the Coulomb interaction. Similarly, the longitudinal emittance growth caused by the energy loss of the beam can be calculated using the differential cross section of the energy-loss distribution. It is shown that particles with energy losses near the maximum energy loss in a head-on collision with a target electron are lost due to momentum acceptance of the HESR ring. Taking a relative momentum acceptance of about 1 x 10{sup -3} into account yields an order of magnitude smaller growth rate of the mean square momentum deviation. The necessary cooling rates for the High Resolution mode and the High Luminosity mode are deduced assuming that the beam-target interaction is the dominant beam heating process. For comparison the effects of intrabeam scattering are estimated. For electron and stochastic cooling, analytic expressions are quoted in order to evaluate the momentum resolution and cooling rate. The potentialities of electron and stochastic cooling are discussed with respect to the achievable momentum resolution and beam-target overlap. Beam loss rates and average luminosities are evaluated taking the total hadronic cross section, the restricted momentum acceptance of the HESR ring, the large angle Coulomb scattering and the Touschek effect into account. (orig.)

  13. Emittance growth and space-charge compensation in the transport of intense ion beams

    International Nuclear Information System (INIS)

    The aim of the GSI transport experiment was the study of the periodic beam transport at space-charge dominated and at partially compensated ion beams. For this purpose a periodic transport channel was constructed which consisted of 6 periods with each two alternatingly poled magnetic quadrupoles. Faraday cups and beam transformers were available for current measurements. At the entrance and the end of the channel the emittances were measured in both transverse planes. The measurements were performed with Ar1+ ions and an energy of 190 keV. The ion currents lied between some μA and 5 mA. The quantity of the rms emittance could be varied from 0.5 mm.mrad to 15 mm.mrad. In agreement with the theoretical considerations the measurement results show that the compensation of the space charge of an ion beam sets on successively. (orig./HSI)

  14. A new stand-alone beam emittance measurement system

    International Nuclear Information System (INIS)

    A unique mechanical arrangement is employed which utilizes a single Allison type emittance scanner pod. This arrangement allows scans to be taken at any rotational angle, thereby eliminating any differences that can occur between gap settings when multiple pods are used. Flexibility is enhanced since the user is not restricted to orthogonal angles. A stand alone control and data acquisition system is utilized. The architecture includes an 80386TM PC and CAMAC interfaces. Two TrekTM power supplies and a computer controlled signal generator provide maximum flexibility to the sweep voltages on the pod deflector plates. This paper describes the mechanical design of the scanner pod assembly, and the electrical and software design of the control system. (orig.)

  15. Optical emitter and amplifier by utilizing traveling electron beam

    OpenAIRE

    Yamada, Minoru; Kuwamura, Yuji

    2008-01-01

    Optical emission and amplification by a travelling electron beam adjacent to a high refractive index waveguide in vacuum was theoretically predicted and experimentally confirmed. Experimentally observed characteristics were compared with theoretical examinations. ©2008 IEEE.

  16. Verification of the AWA Photoinjector Beam Parameters Required for a Transverse-to-Longitudinal Emittance Exchange Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Rihaoui, M.M.; /Northern Illinois U. /Argonne; Piot, P.; /Northern Illinois U. /Fermilab; Power, J.G.; /Argonne; Mihalcea, D.; /Northern Illinois U.; Gai, W.; /Argonne

    2009-05-01

    A transverse-to-longitudinal emittance exchange experiment is in preparation at the Argonne Wakefield Accelerator (AWA). The experiment aims at exchanging a low ({var_epsilon}{sub z} < 5 {micro}m) longitudinal emittance with a large ({var_epsilon}{sub x} > 15 {micro}m) transverse horizontal emittance for a bunch charge of {approx}100 pC. Achieving such initial emittance partitioning, though demonstrated via numerical simulations, is a challenging task and needs to be experimentally verified. In this paper, we report preliminary emittance measurements of the beam in the transverse and longitudinal planes performed at {approx}12 MeV. The measurements are compared with numerical simulations.

  17. Formation of compressed flat electron beams with high transverse-emittance ratios

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, J. [Fermilab; Institute of Fluid Physics, CAEP, China; Piot, P. [Northern Illinois University; Fermilab; Mihalcea, D. [Northern Illinois University; Prokop, C. R. [Northern Illinois University

    2014-08-01

    Flat beams—beams with asymmetric transverse emittances—have important applications in novel light-source concepts and advanced-acceleration schemes and could possibly alleviate the need for damping rings in lepton colliders. Over the last decade, a flat beam generation technique based on the conversion of an angular-momentum-dominated beam was proposed and experimentally tested. In this paper we explore the production of compressed flat beams. We especially investigate and optimize the flat beam transformation for beams with substantial fractional energy spread. We use as a simulation example the photoinjector of Fermilab’s Advanced Superconducting Test Accelerator. The optimizations of the flat beam generation and compression at Advanced Superconducting Test Accelerator were done via start-to-end numerical simulations for bunch charges of 3.2 nC, 1.0 nC, and 20 pC at ~37 MeV. The optimized emittances of flat beams with different bunch charges were found to be 0.25 μm (emittance ratio is ~400), 0.13 μm, 15 nm before compression, and 0.41 μm, 0.20 μm, 16 nm after full compression, respectively, with peak currents as high as 5.5 kA for a 3.2-nC flat beam. These parameters are consistent with requirements needed to excite wakefields in asymmetric dielectric-lined waveguides or produce significant photon flux using small-gap micro-undulators.

  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. A compact proton synchrotron based on a low emittance beam extraction scheme using transverse RF noise

    International Nuclear Information System (INIS)

    A compact proton synchrotron for cancer therapy is presented. In the synchrotron, a new operating scheme for resonant beam extraction is applied with a combined function lattice in order to realize small emittance of the extracted beam with simple control for the accelerator system. In the extraction, the amplitude of the betatron oscillations of the particles inside the separatrix is increased by a transverse RF noise with a narrow bandwidth. During the extraction, the separatrix is kept constant, that is, the magnet currents related to the resonance are kept constant. The emittance of the extracted beam can be kept lower than about 0.1πmm · mrad without dynamic control of the closed orbit. (author)

  20. System for transporting an electron beam to the atmosphere for a gun with a plasma emitter

    Science.gov (United States)

    Kornilov, S. Yu.; Rempe, N. G.; Shidlovskiy, S. V.

    2016-06-01

    We report on the results of simulation of the gas flow in a gun with a plasma emitter and in the system for extracting the electron beam to the atmosphere, constructed on the basis of standard gasdynamic windows (GDWs). The design of the gun and GDWs is described. Calculations are performed for a pressure of about 10-3 Torr in the electron beam generation range. It is shown that the pressure drop to the atmospheric pressure in the system of electron beam extraction to the atmosphere can be ensured by two GDW stages evacuated by pumps with optimal performance.

  1. 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 ...

  2. Intrinsic beam emittance of laser-accelerated electrons measured by x-ray spectroscopic imaging.

    Science.gov (United States)

    Golovin, G; Banerjee, S; Liu, C; Chen, S; Zhang, J; Zhao, B; Zhang, P; Veale, M; Wilson, M; Seller, P; Umstadter, D

    2016-01-01

    The recent combination of ultra-intense lasers and laser-accelerated electron beams is enabling the development of a new generation of compact x-ray light sources, the coherence of which depends directly on electron beam emittance. Although the emittance of accelerated electron beams can be low, it can grow due to the effects of space charge during free-space propagation. Direct experimental measurement of this important property is complicated by micron-scale beam sizes, and the presence of intense fields at the location where space charge acts. Reported here is a novel, non-destructive, single-shot method that overcame this problem. It employed an intense laser probe pulse, and spectroscopic imaging of the inverse-Compton scattered x-rays, allowing measurement of an ultra-low value for the normalized transverse emittance, 0.15 (±0.06) π mm mrad, as well as study of its subsequent growth upon exiting the accelerator. The technique and results are critical for designing multi-stage laser-wakefield accelerators, and generating high-brightness, spatially coherent x-rays. PMID:27090440

  3. Intrinsic beam emittance of laser-accelerated electrons measured by x-ray spectroscopic imaging

    Science.gov (United States)

    Golovin, G.; Banerjee, S.; Liu, C.; Chen, S.; Zhang, J.; Zhao, B.; Zhang, P.; Veale, M.; Wilson, M.; Seller, P.; Umstadter, D.

    2016-04-01

    The recent combination of ultra-intense lasers and laser-accelerated electron beams is enabling the development of a new generation of compact x-ray light sources, the coherence of which depends directly on electron beam emittance. Although the emittance of accelerated electron beams can be low, it can grow due to the effects of space charge during free-space propagation. Direct experimental measurement of this important property is complicated by micron-scale beam sizes, and the presence of intense fields at the location where space charge acts. Reported here is a novel, non-destructive, single-shot method that overcame this problem. It employed an intense laser probe pulse, and spectroscopic imaging of the inverse-Compton scattered x-rays, allowing measurement of an ultra-low value for the normalized transverse emittance, 0.15 (±0.06) π mm mrad, as well as study of its subsequent growth upon exiting the accelerator. The technique and results are critical for designing multi-stage laser-wakefield accelerators, and generating high-brightness, spatially coherent x-rays.

  4. Efficient numerical modelling of the emittance evolution of beams with finite energy spread in plasma wakefield accelerators

    Science.gov (United States)

    Mehrling, T. J.; Robson, R. E.; Erbe, J.-H.; Osterhoff, J.

    2016-09-01

    This paper introduces a semi-analytic numerical approach (SANA) for the rapid computation of the transverse emittance of beams with finite energy spread in plasma wakefield accelerators in the blowout regime. The SANA method is used to model the beam emittance evolution when injected into and extracted from realistic plasma profiles. Results are compared to particle-in-cell simulations, establishing the accuracy and efficiency of the procedure. In addition, it is demonstrated that the tapering of vacuum-to-plasma and plasma-to-vacuum transitions is a viable method for the mitigation of emittance growth of beams during their injection and extraction from and into plasma cells.

  5. Initial Emittance Measurements of the Fermilab Linac Beam Using the MTA Beamline

    CERN Document Server

    Johnstone, C

    2012-01-01

    The MTA beam line has been specifically designed to facilitate measurements of the Fermilab Linac beam emittance and properties utilizing a long, 10m, element-free straight. Linac beam is extracted downstream of the 400-MeV electrostatic chopper located in the Booster injection line. This chopper cannot be utilized for MTA beam, and therefore the entire Linac beam pulse is directed into the MTA beamline. Pulse length manipulation is provided by the 750-keV electrostatic chopper at the upstream end of the Linac and, using this device, beam can be delivered from 8 {\\mu}sec up to the full 50 {\\mu}sec Linac pulse length. The 10 m emittance measurement straight exploits and begins at the 12' shield wall that separates the MTA Experimental Hall and beamline stub from the Linac enclosure. A quadrupole triplet has been installed upstream of the shield wall in order to focus a large, 1.5-2" (~95% width) beam through the shield wall and onto a profile monitor located at the exit of the shielding. Another profile monito...

  6. A pepper-pot emittance meter for low-energy heavy-ion beams

    International Nuclear Information System (INIS)

    A novel emittance meter has been developed to measure the four-dimensional, transverse phase-space distribution of a low-energy ion beam using the pepper-pot technique. A characteristic feature of this instrument is that the pepper-pot plate, which has a linear array of holes in the vertical direction, is scanned horizontally through the ion beam. This has the advantage that the emittance can also be measured at locations along the beam line where the beam has a large horizontal divergence. A set of multi-channel plates, scintillation screen, and ccd camera is used as a position-sensitive ion detector allowing a large range of beam intensities that can be handled. This paper describes the design, construction, and operation of the instrument as well as the data analysis used to reconstruct the four-dimensional phase-space distribution of an ion beam. Measurements on a 15 keV He+ beam are used as an example.

  7. Low emittance pion beams generation from bright photons and relativistic protons

    CERN Document Server

    Serafini, L; Petrillo, V

    2015-01-01

    Present availability of high brilliance photon beams as those produced by X-ray Free Electron Lasers in combination with intense TeV proton beams typical of the Large Hadron Collider makes it possible to conceive the generation of pion beams via photo-production in a highly relativistic Lorentz boosted frame: the main advantage is the low emittance attainable and a TeV-class energy for the generated pions, that may be an interesting option for the production of low emittance muon and neutrino beams. We will describe the kinematics of the two classes of dominant events, i.e. the pion photo-production and the electron/positron pair production, neglecting other small cross-section possible events like Compton and muon pair production. Based on the phase space distributions of the pion and muon beams we will analyze the pion beam brightness achievable in three examples, based on advanced high efficiency high repetition rate FELs coupled to LHC or Future Circular Collider (FCC) proton beams, together with the stud...

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

    International Nuclear Information System (INIS)

    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

  9. A Multislit Transverse-Emittance Diagnostic for Space-Charge-Dominated Electron Beams

    Science.gov (United States)

    Piot, P.; Song, J.; Li, R.; Krafft, G. A.; Jordan, K.; Feldl, E.; Kehne, D.; Denard, J.-C.

    1997-05-01

    Jefferson Lab is building a 10 MeV injector to provide electron beam for a high-power free-electron laser (FEL). To characterize the transverse phase space of the space-charged-dominated beam produced by this injector, we designed an interceptive multislit emittance diagnostic. It incorporates an algorithm for phase-space reconstruction and subsequent calculation of the Twiss parameters and emittance for both transverse directions at an update rate exceeding 1 Hz, a speed that will facilitate the transverse-phase-space matching between the injector and the FEL's accelerator that is critical for proper operation. This paper describes issues pertaining to the diagnostic's design. It also discusses the acquisition system, as well as the software algorithm and its implementation in the FEL control system. First results obtained from testing this diagnostic in Jefferson Lab's Injector Test Stand are also included.

  10. Studies on the nondestructive emittance measurement at a negative-hydrogen-ion beam

    International Nuclear Information System (INIS)

    In the present thesis the already known idea to apply photodetechment for the diagnosis at a H- 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- ions the additional with only 0.754 eV weak bound electron is separated by photodetachment ℎω+H-→H0+e-. The neutralized H- ions can be magnetically or electrostatically separated from the electrons and the remaining H- 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

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

    International Nuclear Information System (INIS)

    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

  12. Studies on space charge neutralization and emittance measurement of beam from microwave ion source

    International Nuclear Information System (INIS)

    A 2.45 GHz microwave ion source together with a beam transport system has been developed at VECC to study the problems related with the injection of high current beam into a compact cyclotron. This paper presents the results of beam profile measurement of high current proton beam at different degrees of space charge neutralisation with the introduction of neon gas in the beam line using a fine leak valve. The beam profiles have been measured at different pressures in the beam line by capturing the residual gas fluorescence using a CCD camera. It has been found that with space charge compensation at the present current level (∼5 mA at 75 keV), it is possible to reduce the beam spot size by ∼34%. We have measured the variation of beam profile as a function of the current in the solenoid magnet under the neutralised condition and used these data to estimate the rms emittance of the beam. Simulations performed using equivalent Kapchinsky-Vladimirsky beam envelope equations with space charge neutralization factor are also presented to interpret the experimental results

  13. 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.

  14. Beam emittance and output waveforms of high-flux laser ion source

    International Nuclear Information System (INIS)

    A laser ion source with short drift distance has been developed for a driver of heavy ion fusion (HIF). It supplies a copper ion beam of 200 mA (255 mA/cm2) with duration of 400 ns and beam emittance is about 0.8π mm·mrad. Moreover it has fast rising (30 ns), flat-top current waveform and a potential to deliver pure charge states between 1+ - 3+. Experimental results indicate that the laser ion source is a good candidate for the HIF driver. (author)

  15. Stable two-plane focusing for emittance-dominated sheet-beam transport

    Science.gov (United States)

    Carlsten, B. E.; Earley, L. M.; Krawczyk, F. L.; Russell, S. J.; Potter, J. M.; Ferguson, P.; Humphries, S.

    2005-06-01

    Two-plane focusing of sheet electron beams will be an essential technology for an emerging class of high-power, 100 to 300 GHz rf sources [Carlsten et al., IEEE Trans. Plasma Sci. 33, 85 (2005), ITPSBD, 0093-3813, 10.1109/TPS.2004.841172]. In these devices, the beam has a unique asymmetry in which the transport is emittance dominated in the sheet’s thin dimension and space-charge dominated in the sheet’s wide dimension. Previous work has studied the stability of the transport of beams in the emittance-dominated regime for both wiggler and periodic permanent magnet (PPM) configurations with single-plane focusing, and has found that bigger envelope scalloping occurs for equilibrium transport, as compared to space-charge dominated beams [Carlsten et al., this issue, Phys. Rev. ST Accel. Beams 8, 062001 (2005), PRABFM, 1098-4402]. In this paper, we describe the differences in transport stability when two-plane focusing is included. Two-plane wiggler focusing degrades the transport stability slightly, whereas two-plane PPM focusing greatly compromises the transport. On the other hand, single-plane PPM focusing can be augmented with external quadrupole fields to provide weak focusing in the sheet’s wide dimension, which has stability comparable to two-plane wiggler transport.

  16. Influence of the electron beam emittance on the polarization of a laser--electron X-ray generator

    CERN Document Server

    Artyukov, I A; Feshchenko, R M

    2016-01-01

    In this paper we analyze the polarization of the X-ray radiation coming from laser--electron X-ray generator (LEXG). We obtain general relations connecting the polarization state of outgoing X-ray radiation to the polarization state of laser beam as well as to the parameters of electron beam. We demonstrate that finite electron beam emittance causes a partial depolarization of initially fully polarized X-ray radiation even when the laser beam is fully polarized. We demonstrate with a number of numerical experiments that finite electron beam emittance can in some cases fundamentally alter the polarization state of X-ray radiation as compared to the polarization state of X-ray radiation scattered by electron beam with a zero emittance. Possible applications of polarized LEXG's radiation are discussed.

  17. Variation of beam emittance during the accelerator cycle of the synchrotron for INDUS-I and INDUS-II

    International Nuclear Information System (INIS)

    The variation of radial and vertical emittance with time is discussed for the synchrotron of INDUS-I and INDUS-II for the acceleration cycle of 1.5 Hz and 2.0 Hz. If adequate provision of time is made for radiation damping at the peak energy, the beam attains the equilibrium value of beam emittance at the extraction point for both the cases. Vertical emittance in both the cases is either less or equal to the natural value. (author). 3 tabs

  18. HIGH AVERAGE CURRENT LOW EMITTANCE BEAM EMPLOYING CW NORMAL CONDUCTING GUN.

    Energy Technology Data Exchange (ETDEWEB)

    CHANG,X.; BEN-ZVI, I.; KEWISCH, J.; PAI, C.

    2007-06-25

    CW normal conducting guns usually do not achieve very high field gradient and waste much RF power at high field gradient compared to superconducting cavities. But they have less trapped modes and wakefields compared to the superconducting cavities due to their low Q. The external bucking coil can also be applied very close to the cathode to improve the beam quality. By using a low frequency gun with a recessed cathode and a carefully designed beam line we can get a high average current and a high quality beam with acceptable RF power loss on the cavity wall. This paper shows that the CW normal conducting gun can be a backup solution for those projects which need high peak and average current, low emittance electron beams such as the Relativistic Heavy Ion Collider (RHIC) e-cooling project and Energy Recovery Linac (Em) project.

  19. Beam emittance growth in a proton storage ring employing charge exchange injection

    International Nuclear Information System (INIS)

    Recently, it has been shown that very large currents can be accumulated in medium energy proton storage rings by multiturn injection of an H- beam through a charge stripping medium. Since the particles are injected continuously into the same phase space, it is possible to increase the circulating beam brightness with respect to that of the incoming beam by a large factor. The stored protons pass repeatedly through the stripper, however, so that this phase space is gradually enlarged by scattering. The dependence of the circulating beam phase space (emittance) growth rate on the nature of the scattering process and on where it occurs in the storage ring matrix is considered. Since the motivation for this work arose in connection with the design of the proposed high-current storage ring at LAMPF, the results are focused on the specific parameters of that device. (U.S.)

  20. Emittance dependence on anode morphology of an ion beam provided by laser ablation

    Energy Technology Data Exchange (ETDEWEB)

    Velardi, L.; Delle Side, D.; Nassisi, V., E-mail: vincenzo.nassisi@le.infn.it

    2014-07-15

    Highlights: •We studied the characteristics of ion beams generated by laser ablation. •We varied the geometric configuration of the extracting electrode. •The emittance evaluation was performed by the pepper pot method utilizing radio-chromic films. -- Abstract: 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 a ns pulsed KrF able to apply irradiances of 10{sup 9}–10{sup 10} W/cm{sup 2}. The target ablated was pure disk of Cu. The accelerating voltage applied in this work was 60 kV. The emittance evaluation was performed by the pepper pot method utilizing 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, e.g. a plane and curved grid 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 was 0.20π mm mrad.

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

    International Nuclear Information System (INIS)

    Sweep plate scanners are preferred for emittance measurement due to their versatility, simplicity, and precision. At the Advanced Technology and Development Center of Northrop Grumman, we have routinely used these devices for characterization of injector beams with less than 20 W/cm2 average power density. To characterize higher power beams, like those required for production of tritium or for radioactive waste transmutation, the scanner pod and data collection algorithm must be redesigned due to the possibility of melting the scanner's protective front face or distorting the precision entrance knife edges. Among the methods we have used to mitigate these effects, one consists of drastically reducing the amount of time required for data collection. In this method, the emittance scanner pod traverses the beam in two passes, each requiring less than 0.5 second. In the first pass, the phase space limits of the beam are determined. In the second pass, data is collected primarily within the phase space region limits determined in the first pass. In this way, enough points are collected to assure that the precision of the measurement is high, even though the data collection time for each scan is less than 0.5 second. This paper will describe the layout of the scanner components, the data collection electronics and algorithm, and the data analysis. (author)

  2. Free-energy formula for emittance-growth estimation in intense mismatched beams

    Science.gov (United States)

    Osaki, Kazuya; Okamoto, Hiromi

    2015-09-01

    We construct a theoretical model that allows a quick estimate of emittance growth in an intense charged-particle beam initially mismatched to an external linear focusing potential. The present theory is a natural generalization of Reiser's free-energy model for coasting round beams in a uniform focusing channel. The free energy generated by a spatial mismatch, i.e. a discrepancy between the ideal beam size and an actual beam size, is calculated for an ellipsoidal bunch with an arbitrary aspect ratio. Following Reiser's prescription, we assume that the excess free energy is converted into root-mean-squared emittance growth. Multi-particle simulations are performed for comparison with theoretical predictions, which indicates that an initially mismatched bunch eventually settles into a sort of thermally anisotropic state when the mismatch is large. It is shown that the free-energy formula can explain simulation results over a wide range of parameters if the degree of the temperature anisotropy in the final state is properly incorporated into the theory.

  3. Possible operation of the European XFEL with ultra-low emittance beams

    International Nuclear Information System (INIS)

    Recent successful lasing of the Linac Coherent Light Source (LCLS) in the hard x-ray regime and the experimental demonstration of a possibility to produce low-charge bunches with ultra-small normalized emittance have lead to the discussions on optimistic scenarios of operation of the European XFEL. In this paper we consider new options that make use of low-emittance beams, a relatively high beam energy, tunable-gap undulators, and a multibunch capability of this facility. We study the possibility of operation of a spontaneous radiator (combining two of them, U1 and U2, in one beamline) in the SASE mode in the designed photon energy range 20-90 keV and show that it becomes possible with ultra-low emittance electron beams similar to those generated in LCLS. As an additional attractive option we consider the generation of powerful soft X-ray and VUV radiation by the same electron bunch for pump-probe experiments, making use of recently invented compact afterburner scheme. We also propose a betatron switcher as a simple, cheap, and robust solution for multi-color operation of SASE1 and SASE2 undulators, allowing to generate 2 to 5 X-ray beams of different independent colors from each of these undulators for simultaneous multi-user operation. We describe a scheme for pump-probe experiments, based on a production of two different colors by two closely spaced electron bunches (produced in photoinjector) with the help of a very fast betatron switcher. Finally, we discuss how without significant modifications of the layout the European XFEL can become a unique facility that continuously covers with powerful, coherent radiation a part of the electromagnetic spectrum from far infrared to gamma-rays. (orig.)

  4. Effect of the electrostatic plasma lens on the emittance of a high-current heavy ion beam

    International Nuclear Information System (INIS)

    We describe measurements we have made of the emittance of a high-current, moderate-energy ion beam after transport through a permanent-magnet electrostatic plasma lens. The results indicate the absence of emittance growth due to the lens, when the lens is adjusted for optimal beam focusing. The measured emittance for a 16 keV Cu2+ ion beam formed by a vacuum arc ion source was about 0.4 π · mm · mrad at a beam current of 50 mA rising more-or-less linearly to 1.5 π · mm · mrad at 250 mA, and was conserved in beam transport through the lens. These results have significance for the application of high-current ion sources and the electrostatic plasma lens to particle accelerator injection

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

    International Nuclear Information System (INIS)

    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.)

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

    International Nuclear Information System (INIS)

    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

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

    Energy Technology Data Exchange (ETDEWEB)

    Ikeda, Shunsuke, E-mail: shunsuke.ikeda@riken.jp; Sekine, Megumi [Tokyo Institute of Technology, Yokohama, Kanagawa (Japan); Riken, Wako, Saitama (Japan); Romanelli, Mark [Cornell University, Ithaca, New York 14850 (United States); Cinquegrani, David [University of Michigan, Ann Arbor, Michigan 48109 (United States); Kumaki, Masafumi [Waseda University, Shinjuku, Tokyo (Japan); Fuwa, Yasuhiro [Kyoto University, Uji, Kyoto (Japan); Kanesue, Takeshi; Okamura, Masahiro [Brookhaven National Laboratory, Upton, New York 11973 (United States); Horioka, Kazuhiko [Tokyo Institute of Technology, Yokohama, Kanagawa (Japan)

    2014-02-15

    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.

  8. 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.

  9. Beam Emittance Measurements for the Low-Energy Demonstration Accelerator Radio-Frequency Quadrupole

    CERN Document Server

    Schulze, M E; Lysenko, W P; Rybarcyk, L J; Schneider, J D; Smith, H V; You, L M

    2000-01-01

    The Low-Energy Demonstration Accelerator (LEDA) radio-frequency quadrupole (RFQ) is a 100% duty factor (CW) linac that delivers >100 mA of H+ beam at 6.7 MeV. The 8-m-long, 350-MHz RFQ structure accelerates a dc, 75-keV, 110-mA H+ beam from the LEDA injector with >90% transmission. LEDA [1,2] consists of a 75-keV proton injector, 6.7-MeV, 350-MHz CW RFQ with associated high-power and low-level rf systems, a short high-energy beam transport (HEBT) and high-power (670-kW CW) beam stop. The beam emittance is inferred from wire scanner measurements of the beam profile at a single location in the HEBT. The beam profile is measured as a function of the magnetic field gradient in one of the HEBT quadrupoles. As the gradient is changed the spot size passes through a transverse waist. Measurements are presented for peak currents between 25 and 100 mA.

  10. Simulation Study on the Emittance Compensation of Off-axis Emitted Beam in RF Photoinjector

    CERN Document Server

    Huang, Rui-Xuan; Jia, Qi-Ka; Papadopoulos, Christos; Sannibale, Fernando

    2016-01-01

    To make full use of photocathode material and improve its quantum efficiency lifetime, it can be necessary to operate laser away from the cathode center in photoinjectors. In RF guns, the off-axis emitted beam will see a time-dependent RF effect, which would generate a significant growth in transverse emittance. It has been demonstrated that such an emittance growth can be almost completely compensated by orienting the beam on a proper orbit in the downstream RF cavities along the injector. In this paper we analyze in detail the simulation techniques used in reference[1] and the issues associated with them. The optimization of photoinjector systems involving off-axis beams is a challenging problem. To solve this problem, one needs advanced simulation tools including both genetic algorithms and an efficient algorithm for 3D space charge. In this paper, we report on simulation studies where the two codes ASTRA and IMPACT-T are used jointly to overcome these challenges, in order to optimize a system designed to ...

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

    International Nuclear Information System (INIS)

    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. - Highlights: ► Ion range verification using PET requires to compare measured with simulated yields. ► Changes in modeling nuclear interactions strongly affect the positron emitter yields. ► Monte Carlo simulations with SHIELD-HIT10A reasonably matched PET isotope experiments. ► None of the employed simulation codes was superior in reproducing all experiments. ► Improved modeling requires more accurate measurements of nuclear cross-sections

  12. The primary test of measuremental system for the actual emittance of relativistic electron beams

    International Nuclear Information System (INIS)

    Recent, a new measuremental system has been established basically in Tsinghua University PRA. This system is able to measure the lower emittance of the electron beams from the RF accelerators for the FEL. It consists of a scanning magnetic field, a slit, a fluorescent screen, and a TV camera, an image processing system, a CAD 386 computer. Using it an actual phase diagram is obtained for 4-10 Mev electron beams, The principle and structure of the facility were reported in the Proceeding of the 15th FEL Conference. This paper describes the performance of the main components and the results of first measurement for the electron gun and 4Mev standing wave LINAC, Some new suggests are related too

  13. Emittance optimisation in the Drive Beam Recombination Complex at CTF3

    CERN Document Server

    Gamba, D

    2014-01-01

    According to the Conceptual Design Report, the power to accelerate the main colliding beams of CLIC is taken from parallel high intensity (100 A), low energy (2.37 GeV) beams. These beams are generated by long trains, accelerated by conventional klystrons and then time-compressed in the so called Drive-Beam Recombination Complex (DBRC). A scaled version of the DBRC has been built at the CLIC Test Facility (CTF3) at CERN in order to prove its principle and study any arising feasibility issues. One of the main constraints is the emittance control during the recombination process. This work presents an overview of the studies ongoing at CTF3, keeping in view possible improvements of the nominal CLIC design. In particular, a generic feedback algorithm to solve (quasi-)linear systems has been implemented and used in order to optimize the process by tuning the energy of the beam and steer the orbits in the different lines, as well matching the design dispersion. Current results and possible room for further optimiz...

  14. A beam profiler and emittance meter for the SPES project at INFN-LNL

    International Nuclear Information System (INIS)

    SPES is a new facility under construction at LNL (Legnaro National Laboratory - Italy) whose aim is the production of radioactive ion beams that will be injected into the Linac ALPI. New beam diagnostics tools have been developed for the SPES project in the perspective of reusing them to upgrade the system currently in operation at LNL in the superconducting Linac ALPI. The goal is providing the SPES facility with an homogenous set of tools and a common user interface to support beam transport over the future accelerators complex. The emittance meter designed for SPES is based on 2 identical moveable slits (collimators) placed in front of a couple of horizontal and vertical grids. The slits have an aperture of 0.3 mm and the distance from the grids is 300 mm. By moving the collimators up and down (or right to left) it is possible to scan the whole beam area and evaluate the beam divergence by measuring the grid currents for different collimator's positions. A control software has been developed using EPICS as general framework

  15. Performance of wire scanner beam profile monitors to determine the emittance and position of high power CW electron beams of the NBS-Los Alamos racetrack microtron

    International Nuclear Information System (INIS)

    The NBS-LANL Race Track Microtron (RTM) injector produces a sub-millimeter diameter, 600 μA, 5 MeV CW electron beam. In order to steer and focus this electron beam and to measure its emittance and energy spread, a system of wire scanner beam profile monitors has been developed. Three wire scanners are mounted in a straight line with approximately one meter spacing for emittance measurements. The fourth wire scanner is positioned after a 450 bending magnet for energy spread measurements

  16. Design of a standing-wave multicell radio frequency cavity beam monitor for simultaneous position and emittance measurement

    International Nuclear Information System (INIS)

    High precision, nondisruptive emittance measurement through second moment monitoring requires precise beam position at the measurement location. We present the design and analysis of a multicavity standing wave structure for a pulse-to-pulse beam position-emittance measurement system in which the quadrupole and the dipole standing wave modes resonate at harmonics of a presumed beam bunch train frequency. As an application for the Next Linear Collider (NLC) beams, an optimized nine-cavity standing-wave structure is designed for simultaneous high precision beam position and emittance measurement. It operates with the π-phase advance quadrupole mode resonating at the 16th harmonic (11.424 GHz) of the NLC bunch frequency and the 3π/4-phase advance dipole mode at the 12th harmonic (8.568 GHz). The output powers from these modes are estimated for the NLC beams. Measurement resolution is estimated to be on the micron scale for rms beam size and on the nanometer scale for beam position

  17. Alpha Particle Emitter Radiolabeled Antibody for Metastatic Cancer: What Can We Learn from Heavy Ion Beam Radiobiology?

    Directory of Open Access Journals (Sweden)

    Hong Song

    2012-06-01

    Full Text Available Alpha-particle emitter labeled monoclonal antibodies are being actively developed for treatment of metastatic cancer due to the high linear energy transfer (LET and the resulting greater biological efficacy of alpha-emitters. Our knowledge of high LET particle radiobiology derives primarily from accelerated heavy ion beam studies. In heavy ion beam therapy of loco-regional tumors, the modulation of steep transition to very high LET peak as the particle approaches the end of its track (known as the Bragg peak enables greater delivery of biologically potent radiation to the deep seated tumors while sparing normal tissues surrounding the tumor with the relatively low LET track segment part of the heavy ion beam. Moreover, fractionation of the heavy ion beam can further enhance the peak-to-plateau relative biological effectiveness (RBE ratio. In contrast, internally delivered alpha particle radiopharmaceutical therapy lack the control of Bragg peak energy deposition and the dose rate is determined by the administered activity, alpha-emitter half-life and biological kinetics of the radiopharmaceutical. The therapeutic ratio of tumor to normal tissue is mainly achieved by tumor specific targeting of the carrier antibody. In this brief overview, we review the radiobiology of high LET radiations learned from ion beam studies and identify the features that are also applicable for the development of alpha-emitter labeled antibodies. The molecular mechanisms underlying DNA double strand break repair response to high LET radiation are also discussed.

  18. Minimization of the emittance growth of multi-charge particle beams in the charge stripping section of RAON

    International Nuclear Information System (INIS)

    The charge stripping section of the Rare isotope Accelerator Of Newness (RAON), which is one of the critical components to achieve a high power of 400 kW with a short lianc, is a source of transverse emittance growth. The dominant effects are the angular straggling in the charge stripper required to increase the charge state of the beam and chromatic aberrations in the dispersive section required to separate the selected ion beam from the various ion beams produced in the stripper. Since the main source of transverse emittance growth in the stripper is the angular straggling, it can be compensated for by changing the angle of the phase ellipse. Therefore the emittance growth is minimized by optimizing the Twiss parameters at the stripper. The emittance growth in the charge selection section is also minimized by the correction of high-order aberrations using six sextupole magnets. In this paper, we present a method to minimize the transverse emittance growth in the stripper by changing the Twiss parameters and in the charge selection section by using sextupole magnets

  19. Lead ion beam emittance and transmission studies in the PS-SPS complex at CERN

    CERN Document Server

    Arduini, Gianluigi; Bohl, T; Burkhardt, H; Cappi, R; Carter, C; Cornelis, Karel; Dach, M; de Rijk, G; Faugier, A; Ferioli, G; Jakob, H; Jonker, M; Manglunki, Django; Martini, G; Martini, M; Riunaud, J P; Scheidenberger, C; Vandorpe, B; Vos, L; Zanolli, M

    1996-01-01

    In the Lead Ion Facility at CERN [1] Pb53+ ion beams are accelerated up to a kinetic energy of 4.2 GeV/u in the CERN PS, extracted and stripped to Pb82+ in the transfer line from PS to SPS where they are injected and accelerated up to 157 GeV/u. The stripping efficiency, emittance growth and energy loss in Al strippers of different thicknesses have been measured and they are in good agreement with the theoretical values. The results of these measurements and considerations on the PS-SPS transmission efficiency are presented. [1] D. Warner, ed., ŒCERN Heavy-Ion Facility Design Report¹, CERN 93-01.

  20. Evaluation of Rosenbaum's proposal for locally increasing the effective vertical emittance of the APS beam.

    CERN Document Server

    Emery, L; Sereno, N S

    2003-01-01

    At the APS Retreat in May 2002, G. Rosenbaum proposed a method for increasing the effective vertical emittance of the APS beam. His proposal, illustrated in Figure 1, is to use a rapidly-modulated four-magnet vertical position bump in a single straight section. The proposed modulation frequency is a 10-kHz triangle wave, with a kick angle of 0.65 mrad. There are several aspects of this proposal that may be problematical: (1) The high modulation frequency will require the use of a ceramic chamber with a thin conductive coating, similar to what is used for the injection kicker magnets. This is not necessarily a problem, but the following aspects need to be examined: (a) The chamber coating needs to be specified correctly to ensure that the beam motion reflects the desired triangle-wave pattern. (b) The effect of the eddy currents in the chamber on the multipole content of the magnetic field needs to be computed, to ensure that the system does not have undesirable effects on the beam. (2) The magnets and their c...

  1. Start-up of beam emittance shaping line of the NIIYaF MGU continuous action racetrack microtron

    International Nuclear Information System (INIS)

    Results of start-up of longitudinal and transverse emittance shaping line for 100 keV and up to 10 mA electron beam of aracetrack microtron are presented. The shaping line includes electron gun, magnetic lenses, correctors, vacuum seal, profile monitor. The line permit to obtain 10-15 deg of bunching. 6 refs.; 3 figs

  2. Nano-modulated electron beams via electron diffraction and emittance exchange for coherent x-ray generation

    OpenAIRE

    Nanni, Emilio A.; Graves, William S.; Moncton, David E.

    2015-01-01

    A new method for generation of relativistic electron beams with current modulations at nanometer scale and below is presented. The current modulation is produced by diffracting relativistic electrons in perfect crystal Si, accelerating the diffracted beam and imaging the crystal structure, then transferring the image into the temporal dimension via emittance exchange. The modulation period can be tuned by adjusting electron optics after diffraction. This tunable longitudinal modulation can ha...

  3. Method for maximizing the brightness of the bunches in a particle injector by converting a highly space-charged beam to a relativistic and emittance-dominated beam

    Energy Technology Data Exchange (ETDEWEB)

    Hannon, Fay

    2016-08-02

    A method for maximizing the brightness of the bunches in a particle injector by converting a highly space-charged beam to a relativistic and emittance-dominated beam. The method includes 1) determining the bunch charge and the initial kinetic energy of the highly space-charge dominated input beam; 2) applying the bunch charge and initial kinetic energy properties of the highly space-charge dominated input beam to determine the number of accelerator cavities required to accelerate the bunches to relativistic speed; 3) providing the required number of accelerator cavities; and 4) setting the gradient of the radio frequency (RF) cavities; and 5) operating the phase of the accelerator cavities between -90 and zero degrees of the sinusoid of phase to simultaneously accelerate and bunch the charged particles to maximize brightness, and until the beam is relativistic and emittance-dominated.

  4. Acceleration of Ultra-Low Emittance Proton and Ion Beams with High Intensity Lasers

    Science.gov (United States)

    Cowan, Thomas E.

    2002-11-01

    Intense beams of several MeV protons and ions, generated by the interaction of high-intensity short pulse lasers with thin foils, have been observed by many researchers in recent years.(S.P. Hatchett et al., Phys. Plasmas 7, 2076 (2000); T.E. Cowan et al., Nucl. Inst. Meth. A 455, 130 (2000); R.A. Snavely et al., Phys. Rev. Lett. 85, 2945 (2000); S.C. Wilks et al., Phys. Plasmas 8, 532 (2000); E. Clark et al., Phys. Rev. Lett. 84, 670 (2000).) In experiments performed at the 100 TW LULI laser, we have succeeded to control the ion acceleration process to produce ultra high quality proton beams, whose transverse emittance is laser-plasma interaction, of the transport of MA currents of relativistic electrons through the target substrate, and of the surface topology and source material layering on the target foil rear-surface.(M. Roth et al., Phys. Rev. ST Accel. Beams 5, 061002 (2002).) By varying the source material, we also accelerated light ion beams, such as He-like fluorine, to over 5 MeV/nucleon.(M. Hegelich et al., Phys. Rev. Lett. 89, 085002 (2002).) From PIC simulations we understand the highest-energy and lowest-divergence proton acceleration as a transient laser-driven virtual cathode effect occurring at the target rear-surface. We have also confirmed the acceleration of ions from the front surface (A. Maksimchuk et al., Phys. Rev. Lett. 84, 4108 (2000).), which we find exhibits an intense low-energy component, but only a tenuous high-energy component, in agreement with PIC simulations. This work was performed with corporate support of General Atomics.

  5. Microcontroller based motion control interface unit for double slit type beam emittance monitor for H- ion source

    International Nuclear Information System (INIS)

    The Indian Spallation Neutron Source (ISNS), proposed to be developed at RRCAT, will use a 1 GeV H- linac and an accumulator ring to produce high flux of pulsed neutrons via spallation process. The development activity of front end of 1H- linac for ISNS is under progress at RRCAT, for which a pulsed H- ion source of 50 keV energy, 30 mA current with pulse width of 500 μs has been developed at RRCAT. In this paper, we present the design and development of a microcontroller based motion control interface unit for double slit type beam emittance monitor for the H- ion source. This is an interceptive type of beam diagnostic device, which is used for the quantitative measurement of transverse emittance and beam intensity profile

  6. 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.

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

    International Nuclear Information System (INIS)

    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.

  8. Effective source size, radial, angular and energy spread of therapeutic 11C positron emitter beams produced by 12C fragmentation

    International Nuclear Information System (INIS)

    The use of positron emitter light ion beams in combination with PET (Positron Emission Tomography) and PET–CT (Computed Tomography) imaging could significantly improve treatment verification and dose delivery imaging during radiation therapy. The present study is dedicated to the analysis of the beam quality in terms of the effective source size, as well as radial, angular and energy spread of the 11C ion beam produced by projectile fragmentation of a primary point monodirectional and monoenergetic 12C ion beam in a dedicated range shifter of different materials. This study was performed combining analytical methods describing the transport of particles in matter and the Monte Carlo code SHIELD-HIT+. A high brilliance and production yield of 11C fragments with a small effective source size and emittance is best achieved with a decelerator made of two media: a first liquid hydrogen section of about 20 cm followed by a hydrogen rich section of variable length. The calculated intensity of the produced 11C ion beam ranges from about 5% to 8% of the primary 12C beam intensity depending on the exit energy and the acceptance of the beam transport system. The angular spread is lower than 1 degree for all the materials studied, but the brilliance of the beam is the highest with the proposed mixed decelerator

  9. 低能离子束横向发射度的测量及分析%Measuring and Analyzing Transverse Low-Energy Ion Beam Emittances

    Institute of Scientific and Technical Information of China (English)

    M.P.Stockli

    2007-01-01

    The transverse emittance of an ion beam describes its transverse size as the particles are transported from a source to a target.It allows for predicting beam losses in limiting apertures and the beam focus size at the target.Various definitions and issues are discussed.The most common and emerging measuring techniques are presented,including their advantages.Several methods of emittance data analysis,their accuracy and trustworthiness,are discussed.

  10. Short-lived positron emitters in beam-on PET imaging during proton therapy

    International Nuclear Information System (INIS)

    The only method for in vivo dose delivery verification in proton beam radiotherapy in clinical use today is positron emission tomography (PET) of the positron emitters produced in the patient during irradiation. PET imaging while the beam is on (so called beam-on PET) is an attractive option, providing the largest number of counts, the least biological washout and the fastest feedback. In this implementation, all nuclides, independent of their half-life, will contribute. As a first step towards assessing the relevance of short-lived nuclides (half-life shorter than that of 10C, T1/2  =  19 s) for in vivo dose delivery verification using beam-on PET, we measured their production in the stopping of 55 MeV protons in water, carbon, phosphorus and calcium The most copiously produced short-lived nuclides and their production rates relative to the relevant long-lived nuclides are: 12N (T1/2  =  11 ms) on carbon (9% of 11C), 29P (T1/2  =  4.1 s) on phosphorus (20% of 30P) and 38mK (T1/2  =  0.92 s) on calcium (113% of 38gK). No short-lived nuclides are produced on oxygen. The number of decays integrated from the start of an irradiation as a function of time during the irradiation of PMMA and 4 tissue materials has been determined. For (carbon-rich) adipose tissue, 12N dominates up to 70 s. On bone tissue, 12N dominates over 15O during the first 8–15 s (depending on carbon-to-oxygen ratio). The short-lived nuclides created on phosphorus and calcium provide 2.5 times more beam-on PET counts than the long-lived ones produced on these elements during a 70 s irradiation. From the estimated number of 12N PET counts, we conclude that, for any tissue, 12N PET imaging potentially provides equal to superior proton range information compared to prompt gamma imaging with an optimized knife-edge slit camera. The practical implementation of 12N PET imaging is discussed. (paper)

  11. Short-lived positron emitters in beam-on PET imaging during proton therapy

    Science.gov (United States)

    Dendooven, P.; Buitenhuis, H. J. T.; Diblen, F.; Heeres, P. N.; Biegun, A. K.; Fiedler, F.; van Goethem, M.-J.; van der Graaf, E. R.; Brandenburg, S.

    2015-12-01

    The only method for in vivo dose delivery verification in proton beam radiotherapy in clinical use today is positron emission tomography (PET) of the positron emitters produced in the patient during irradiation. PET imaging while the beam is on (so called beam-on PET) is an attractive option, providing the largest number of counts, the least biological washout and the fastest feedback. In this implementation, all nuclides, independent of their half-life, will contribute. As a first step towards assessing the relevance of short-lived nuclides (half-life shorter than that of 10C, T1/2  =  19 s) for in vivo dose delivery verification using beam-on PET, we measured their production in the stopping of 55 MeV protons in water, carbon, phosphorus and calcium The most copiously produced short-lived nuclides and their production rates relative to the relevant long-lived nuclides are: 12N (T1/2  =  11 ms) on carbon (9% of 11C), 29P (T1/2  =  4.1 s) on phosphorus (20% of 30P) and 38mK (T1/2  =  0.92 s) on calcium (113% of 38gK). No short-lived nuclides are produced on oxygen. The number of decays integrated from the start of an irradiation as a function of time during the irradiation of PMMA and 4 tissue materials has been determined. For (carbon-rich) adipose tissue, 12N dominates up to 70 s. On bone tissue, 12N dominates over 15O during the first 8-15 s (depending on carbon-to-oxygen ratio). The short-lived nuclides created on phosphorus and calcium provide 2.5 times more beam-on PET counts than the long-lived ones produced on these elements during a 70 s irradiation. From the estimated number of 12N PET counts, we conclude that, for any tissue, 12N PET imaging potentially provides equal to superior proton range information compared to prompt gamma imaging with an optimized knife-edge slit camera. The practical implementation of 12N PET imaging is discussed.

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

    International Nuclear Information System (INIS)

    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

  13. Measurement of the transverse four-dimensional beam rms-emittance of an intense uranium beam at 11.4 MeV/u

    Science.gov (United States)

    Xiao, C.; Groening, L.; Gerhard, P.; Maier, M.; Mickat, S.; Vormann, H.

    2016-06-01

    Knowledge of the transverse four-dimensional beam rms-parameters is essential for applications that involve lattice elements that couple the two transverse degrees of freedom (planes). Usually pepper-pots are used for measuring these beam parameters. However, for ions their application is limited to energies below 150 keV/u. This contribution is on measurements of the full transverse four-dimensional second-moments beam matrix of high intensity uranium ions at an energy of 11.4 MeV/u. The combination of skew quadrupoles with a slit/grid emittance measurement device has been successfully applied.

  14. 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 ...

  15. 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...

  16. Nano-modulated electron beams via electron diffraction and emittance exchange for coherent x-ray generation

    CERN Document Server

    Nanni, Emilio A; Moncton, David E

    2015-01-01

    A new method for generation of relativistic electron beams with current modulations at nanometer scale and below is presented. The current modulation is produced by diffracting relativistic electrons in perfect crystal Si, accelerating the diffracted beam and imaging the crystal structure, then transferring the image into the temporal dimension via emittance exchange. The modulation period can be tuned by adjusting electron optics after diffraction. This tunable longitudinal modulation can have a period as short as a few angstroms, enabling production of coherent hard x-rays from a device based on inverse Compton scattering with total length of a few meters. Electron beam simulations from cathode emission through diffraction, acceleration and image formation with variable magnification are presented along with estimates of the coherent x-ray output properties.

  17. Measurement of electron-beam bunch length and emittance using shot-noise-driven fluctuations in incoherent radiation

    International Nuclear Information System (INIS)

    Longitudinal and transverse phase space information has been obtained from a statistical analysis of fluctuations in the radiation spectrum of an electron bunch. Uncorrelated shot noise fluctuations in longitudinal beam density result in incoherent radiation with a spectrum that consists of spikes, with width inversely proportional to the bunch length. Measurements were performed at λ=620 nm on a 1--5 ps long, 44 MeV bunch propagating through a wiggler. Bunch length and emittance obtained with this single shot technique agree with independent measurements

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

    Science.gov (United States)

    Jiang, Bo-Cheng; Zhao, Zhen-tang; Feng, Chao

    2014-11-01

    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. Development of a MEMS electrostatic condenser lens array for nc-Si surface electron emitters of the Massive Parallel Electron Beam Direct-Write system

    Science.gov (United States)

    Kojima, A.; Ikegami, N.; Yoshida, T.; Miyaguchi, H.; Muroyama, M.; Yoshida, S.; Totsu, K.; Koshida, N.; Esashi, M.

    2016-03-01

    Developments of a Micro Electro-Mechanical System (MEMS) electrostatic Condenser Lens Array (CLA) for a Massively Parallel Electron Beam Direct Write (MPEBDW) lithography system are described. The CLA converges parallel electron beams for fine patterning. The structure of the CLA was designed on a basis of analysis by a finite element method (FEM) simulation. The lens was fabricated with precise machining and assembled with a nanocrystalline silicon (nc-Si) electron emitter array as an electron source of MPEBDW. The nc-Si electron emitter has the advantage that a vertical-emitted surface electron beam can be obtained without any extractor electrodes. FEM simulation of electron optics characteristics showed that the size of the electron beam emitted from the electron emitter was reduced to 15% by a radial direction, and the divergence angle is reduced to 1/18.

  20. Electron beam collimation with a 40 000 tip metallic double-gate field emitter array and in-situ control of nanotip sharpness distribution

    OpenAIRE

    Helfenstein, P.; Guzenko, V.A.; Fink, H W; Tsujino, S

    2013-01-01

    The generation of highly collimated electron beams from a double-gate field emitter array with 40000 metallic tips and large collimation gate apertures is reported. Field emission beam measurements demonstrated the reduction of the beam envelope down to the array size by applying a negative potential to the on-chip gate electrode for the collimation of individual field emission beamlets. Owing to the optimized gate structure, the concomitant decrease of the emission current was minimal, leadi...

  1. High Power Beam Test and Measurement of Emittance Evolution of a 1.6-Cell Photocathode RF Gun at Pohang Accelerator Laboratory

    Science.gov (United States)

    Park, Jang-Ho; Park, Sung-Ju; Kim, Changbum; Parc, Yong-Woon; Hong, Ju-Ho; Huang, Jung-Yun; Xiang, Dao; Wang, Xijie; Ko, In Soo

    2007-04-01

    A Brookhaven National Laboratory (BNL) GUN-IV type photocathode rf gun has been fabricated to use in femtosecond electron diffraction (FED), femtosecond far infrared radiation (fs-FIR) facility, and X-ray free electron laser (XFEL) facilities at the Pohang Accelerator Laboratory (PAL). The gun consists of a 1.6-cell cavity with a copper cathode, a solenoid magnet, beam diagnostic components and auxiliary systems. We report here the measurement of the basic beam parameters which confirm a successful fabrication of the photocathode RF gun system. The emittance evolution is measured by an emittance meter and compared with the PARMELA simulation, which shows a good agreement.

  2. Development of a pepper-pot device to determine the emittance of an ion beam generated by electron cyclotron resonance ion sources

    International Nuclear Information System (INIS)

    This paper describes the recent development and commissioning of a pepper-pot emittance meter at the Lawrence Berkeley National Laboratory (LBNL). It is based on a potassium bromide (KBr) scintillator screen in combination with a charged coupled device camera. Pepper-pot scanners record the full four-dimensional transverse phase space emittances which are particularly interesting for electron cyclotron resonance ion sources. The strengths and limitations of evaluating emittances using optical pepper-pot scanners are described and systematic errors induced by the optical data acquisition system will be presented. Light yield tests of KBr exposed to different ion species and first emittance measurement data using ion beams extracted from the 6.4 GHz LBNL electron cyclotron resonance ion source are presented and discussed.

  3. Beam Emittance Measurements for the Low-Energy Demonstration Accelerator Radio-Frequency Quadrupole

    OpenAIRE

    Schulze, M. E.; Gilpatrick, J.D.; Lysenko, W. P.; Rybarcyk, L. J.; Schneider, J. D.; Smith, Jr., Norman Austin; You, L. M.

    2000-01-01

    The Low-Energy Demonstration Accelerator (LEDA) radio-frequency quadrupole (RFQ) is a 100% duty factor (CW) linac that delivers >100 mA of H+ beam at 6.7 MeV. The 8-m-long, 350-MHz RFQ structure accelerates a dc, 75-keV, 110-mA H+ beam from the LEDA injector with >90% transmission. LEDA [1,2] consists of a 75-keV proton injector, 6.7-MeV, 350-MHz CW RFQ with associated high-power and low-level rf systems, a short high-energy beam transport (HEBT) and high-power (670-kW CW) beam stop. The beam...

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

    International Nuclear Information System (INIS)

    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

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

    Science.gov (United States)

    Carlsten, B. E.; Earley, L. M.; Krawczyk, F. L.; Russell, S. J.; Potter, J. M.; Ferguson, P.; Humphries, S.

    2005-06-01

    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 (2005), ITPSBD, 0093-3813, 10.1109/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 a cross section of

  7. Emittance measurements on ETA and ATA

    International Nuclear Information System (INIS)

    Emittance measurements on beams produced by the ETA and ATA accelerators are discussed. Emittance and brightness are defined. The significance of emittance for a beam in an accelerator and in gas is discussed. Various measurement techniques and results are presented and contrasted. Implicit calculations of emittance are also reported. Finally, the measurement of the time variation of emittance is discussed and the techniques to be used on the upcoming ATA experiments are outlined

  8. Transverse Phase Space Reconstruction and Emittance Measurement of Intense Electron Beams using a Tomography Technique

    International Nuclear Information System (INIS)

    Tomography is the technique of reconstructing an image from its projections. It is widely used in the medical community to observe the interior of the human body by processing multiple x-ray images taken at different angles, A few pioneering researchers have adapted tomography to reconstruct detailed phase space maps of charged particle beams. Some questions arise regarding the limitations of tomography technique for space charge dominated beams. For instance is the linear space charge force a valid approximation? Does tomography equally reproduce phase space for complex, experimentally observed, initial particle distributions? Does tomography make any assumptions about the initial distribution? This study explores the use of accurate modeling with the particle-in-cell code WARP to address these questions, using a wide range of different initial distributions in the code. The study also includes a number of experimental results on tomographic phase space mapping performed on University of Maryland Electron Ring (UMER)

  9. Emittance measurements by variable quadrupole method

    International Nuclear Information System (INIS)

    The beam emittance is a measure of both the beam size and beam divergence, we cannot directly measure its value. If the beam size is measured at different locations or under different focusing conditions such that different parts of the phase space ellipse will be probed by the beam size monitor, the beam emittance can be determined. An emittance measurement can be performed by different methods. Here we will consider the varying quadrupole setting method.

  10. FEL gain taking into account diffraction and electron beam emittance; generalized Madey's theorem

    International Nuclear Information System (INIS)

    We derive a formula for the free electron laser gain in the small-signal, low-grain regime which resembles closely the 1-D formula but taking into account the effect of wave diffraction and electron beam divergence and betatron motion. The formula is cast in a form which exhibits clearly the role of the transverse phase space distribution of photons and electrons. 8 refs

  11. Emittance Measurements of the Electron Beam at PITZ for the Commissioning Phase of the European XFEL

    OpenAIRE

    Vashchenko, G.; Asova, G.; Khojoyan, M; Kourkafas, G.; Kraslinikov, M.; Malyutin, D.; Melkumyan, D.; Oppelt, A.; Otevrel, M.; Renier, Y.; Rublack, T.; Stephan, F.; Bakr, M.; Zhao, Q.; Lishilin, O.

    2015-01-01

    For the operation of free electron lasers (FELs) like the European XFEL and FLASH located at DESY, Hamburg Site,high quality electron beams are required already from the source. The Photo Injector Test facility at DESY, ZeuthenSite (PITZ), was established to develop, characterize and optimize electron sources for such FELs. Last year the workat PITZ focused on the optimization of a photo injector operated very close to the startup parameters of the EuropeanXFEL. This implies photocathode lase...

  12. Study of the time and space distribution of $\\beta^+$ emitters from $80\\ \\mega\\electronvolt/$u carbon ion beam irradiation on PMMA

    CERN Document Server

    Agodi, C; Cirrone, G A P; Collamati, F; Cuttone, G; De Lucia, E; De Napoli, M; Di Domenico, A; Faccini, R; Ferroni, F; Fiore, S; Gauzzi, P; Iarocci, E; Marafini, M; Mattei, I; Paoloni, A; Patera, V; Piersanti, L; Romano, F; Sarti, A; Sciubba, A; Voena, C

    2012-01-01

    Proton and carbon ion therapy is an emerging technique used for the treatment of solid cancers. The monitoring of the dose delivered during such treatments and the on-line knowledge of the Bragg peak position is still a matter of research. A possible technique exploits the collinear $511\\ \\kilo\\electronvolt$ photons produced by positrons annihilation from $\\beta^+$ emitters created by the beam. This paper reports rate measurements of the $511\\ \\kilo\\electronvolt$ photons emitted after the interactions of a $80\\ \\mega\\electronvolt / u$ fully stripped carbon ion beam at the Laboratori Nazionali del Sud (LNS) of INFN, with a Poly-methyl methacrylate target. The time evolution of the $\\beta^+$ rate was parametrized and the dominance of $^{11}C$ emitters over the other species ($^{13}N$, $^{15}O$, $^{14}O$) was observed, measuring the fraction of carbon ions activating $\\beta^+$ emitters $A_0=(10.3\\pm0.7)\\cdot10^{-3}$. The average depth in the PMMA of the positron annihilation from $\\beta^+$ emitters was also meas...

  13. Study of the time and space distribution of {beta}{sup +} emitters from 80MeV/u carbon ion beam irradiation on PMMA

    Energy Technology Data Exchange (ETDEWEB)

    Agodi, C. [Laboratori Nazionali del Sud dell' INFN, Catania (Italy); Bellini, F. [Dipartimento di Fisica, Sapienza Universita di Roma, Roma (Italy); INFN Sezione di Roma, Roma (Italy); Cirrone, G.A.P. [Laboratori Nazionali del Sud dell' INFN, Catania (Italy); Collamati, F. [Dipartimento di Fisica, Sapienza Universita di Roma, Roma (Italy); INFN Sezione di Roma, Roma (Italy); Cuttone, G. [Laboratori Nazionali del Sud dell' INFN, Catania (Italy); De Lucia, E. [Laboratori Nazionali di Frascati dell' INFN, Frascati (Italy); De Napoli, M. [Laboratori Nazionali del Sud dell' INFN, Catania (Italy); Di Domenico, A.; Faccini, R.; Ferroni, F. [Dipartimento di Fisica, Sapienza Universita di Roma, Roma (Italy); INFN Sezione di Roma, Roma (Italy); Fiore, S. [Dipartimento di Fisica, Sapienza Universita di Roma, Roma (Italy); Gauzzi, P. [Dipartimento di Fisica, Sapienza Universita di Roma, Roma (Italy); INFN Sezione di Roma, Roma (Italy); Iarocci, E. [Laboratori Nazionali di Frascati dell' INFN, Frascati (Italy); Dipartimento di Scienze di Base e Applicate per l' Ingegneria, Sapienza Universita di Roma, Roma (Italy); Marafini, M., E-mail: michela.marafini@roma1.infn.it [Museo Storico della Fisica e Centro Studi e Ricerche ' E. Fermi' , Roma (Italy); Mattei, I. [Dipartimento di Fisica, Roma Tre Universita di Roma, Roma (Italy); Laboratori Nazionali di Frascati dell' INFN, Frascati (Italy); Paoloni, A. [Laboratori Nazionali di Frascati dell' INFN, Frascati (Italy); and others

    2012-07-15

    Proton and carbon ion therapy is an emerging technique used for the treatment of solid cancers. The monitoring of the dose delivered during such treatments and the on-line knowledge of the Bragg peak position is still a matter of research. A possible technique exploits the collinear 511keV photons produced by positrons annihilation from {beta}{sup +} emitters created by the beam. This paper reports rate measurements of the 511keV photons emitted after the interactions of a 80MeV/u fully stripped carbon ion beam at the Laboratori Nazionali del Sud (LNS) of INFN, with a poly-methyl methacrylate target. The time evolution of the {beta}{sup +} rate was parametrized and the dominance of {sup 11}C emitters over the other species ({sup 13}N, {sup 15}O, {sup 14}O) was observed, measuring the fraction of carbon ions activating {beta}{sup +} emitters to be (10.3{+-}0.7) Multiplication-Sign 10{sup -3}. The average depth in the PMMA of the positron annihilation from {beta}{sup +} emitters was also measured, D{sub {beta}{sup +}}=5.3{+-}1.1mm, to be compared to the expected Bragg peak depth D{sub Bragg}=11.0{+-}0.5mm obtained from simulations.

  14. Intracavity contacts for nitride based monolithic surface emitters by focused ion beam processing

    International Nuclear Information System (INIS)

    The realization of electrically driven nitride based vertical-cavity surface-emitting lasers (VCSELs) is challenging due to limitations in the conductivity of the distributed Bragg reflectors (DBRs). Therefore monolithic approaches are based on a doped cavity and one or two undoped DBRs. This requires the use of technologically complex intracavity contacts. The presented process yields intracavity contacts applicable to monolithically grown VCSEL structures. Initially mesas are structured by photolithography and chemical assisted ion beam etching. The precise structuring of the prestructured mesas is performed in a focused ion beam system (FIB), where the micropillars are thinned stepwise down to a diameter of 0.5-5 μm. The contacting of the pillars is realized by FIB deposited metal and insulator structures. Insulator separated Pt ring-contacts connect the micropillars with large-scale contact pads. This procedure was applied to a VCSEL structure consisting of a bottom AlInN/GaN-DBR with 40 pairs, a p/n-doped 5 λ GaN-cavity with embedded InGaN quantum dots and a top 10 pair AlInN/GaN-DBR. The developed contacting structure enables a current up to 15 mA through the cavity which documents the capability for the electrical operation of VCSEL devices.

  15. Intracavity contacts for nitride based monolithic surface emitters by focused ion beam processing

    Energy Technology Data Exchange (ETDEWEB)

    Fandrich, Malte; Dartsch, Heiko; Tessarek, Christian; Aschenbrenner, Timo; Hommel, Detlef [Institut fuer Festkoerperphysik - Halbleiterepitaxie, Universitaet Bremen (Germany)

    2010-07-01

    The realization of electrically driven nitride based vertical-cavity surface-emitting lasers (VCSELs) is challenging due to limitations in the conductivity of the distributed Bragg reflectors (DBRs). Therefore monolithic approaches are based on a doped cavity and one or two undoped DBRs. This requires the use of technologically complex intracavity contacts. The presented process yields intracavity contacts applicable to monolithically grown VCSEL structures. Initially mesas are structured by photolithography and chemical assisted ion beam etching. The precise structuring of the prestructured mesas is performed in a focused ion beam system (FIB), where the micropillars are thinned stepwise down to a diameter of 0.5-5 {mu}m. The contacting of the pillars is realized by FIB deposited metal and insulator structures. Insulator separated Pt ring-contacts connect the micropillars with large-scale contact pads. This procedure was applied to a VCSEL structure consisting of a bottom AlInN/GaN-DBR with 40 pairs, a p/n-doped 5 {lambda} GaN-cavity with embedded InGaN quantum dots and a top 10 pair AlInN/GaN-DBR. The developed contacting structure enables a current up to 15 mA through the cavity which documents the capability for the electrical operation of VCSEL devices.

  16. Monitoring the irradiation field of 12C and 16O SOBP beams using positron emitters produced through projectile fragmentation reactions

    International Nuclear Information System (INIS)

    In order to effectively utilize the prominent properties of heavy ions in radiotherapy, it is important to evaluate both the position of the field irradiated with incident ions and the absorbed dose distribution in a patient's body. One of the methods for this purpose is the utilization of the positron emitters produced through the projectile fragmentation reactions of stable heavy ions with target nuclei. In heavy-ion therapy, spread-out Bragg peak (SOBP) beams are used to achieve uniform biological dose distributions in the whole tumor volume. Therefore, in this study, we designed SOBP beams of 30 and 50 mm water-equivalent length (mmWEL) in width for 12C and 16O, and carried out irradiation experiments using them. Water, polyethylene and polymethyl methacrylate were selected as targets to simulate a human body. Pairs of annihilation gamma rays were detected by means of a limited-angle positron camera for 500 s, and annihilation gamma-ray distributions were obtained. The maximum likelihood estimation (MLE) method was applied to the detected distributions for evaluating the positions of the distal and proximal edges of the SOBP in a target. The differences between the positions evaluated with the MLE method and those derived from the measured dose distributions were less than 1.7 mm and 2.5 mm for the distal and the proximal edge, respectively, in all irradiation conditions. When the positions of both edges are determined with the MLE method, the most probable shape of the dose distribution in a target can be estimated simultaneously. The close agreement between the estimated and the measured distributions implied that the shape of the dose distribution in an irradiated target could be evaluated from the detected annihilation gamma-ray distribution

  17. Evidence for high-energy and low-emittance electron beams using ionization injection of charge in a plasma wakefield accelerator

    CERN Document Server

    Vafaei-Najafabadi, N; Clayton, C E; Joshi, C; Marsh, K A; Mori, W B; Welch, E C; Lu, W; Adli, E; Allen, J; Clarke, C I; Corde, S; Frederico, J; Gessner, S J; Green, S Z; Hogan, M J; Litos, M D; Yakimenko, V

    2015-01-01

    Ionization injection in a plasma wakefield accelerator was investigated experimentally using two lithium plasma sources of different lengths. The ionization of the helium gas, used to confine the lithium, injects electrons in the wake. After acceleration, these injected electrons were observed as a distinct group from the drive beam on the energy spectrometer. They typically have a charge of tens of pC, an energy spread of a few GeV, and a maximum energy of up to 30 GeV. The emittance of this group of electrons can be many times smaller than the initial emittance of the drive beam. The energy scaling for the trapped charge from one plasma length to the other is consistent with the blowout theory of the plasma wakefield.

  18. Low-emittance Storage Rings

    CERN Document Server

    Wolski, A

    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.

  19. Electron beam collimation with a 40 000 tip metallic double-gate field emitter array and in-situ control of nanotip sharpness distribution

    Energy Technology Data Exchange (ETDEWEB)

    Helfenstein, P.; Guzenko, V. A.; Tsujino, S. [Laboratory for Micro- and Nanotechnology, Paul Scherrer Institut, CH-5232 Villigen-PSI (Switzerland); Fink, H.-W. [Physik Institut, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich (Switzerland)

    2013-01-28

    The generation of highly collimated electron beams from a double-gate field emitter array with 40000 metallic tips and large collimation gate apertures is reported. Field emission beam measurements demonstrated the reduction of the beam envelope down to the array size by applying a negative potential to the on-chip gate electrode for the collimation of individual field emission beamlets. Owing to the optimized gate structure, the concomitant decrease of the emission current was minimal, leading to a net enhancement of the current density. Furthermore, a noble gas conditioning process was successfully applied to the double-gate device to improve the beam uniformity in-situ with orders of magnitude increase of the active emission area. The results show that the proposed double-gate field emission cathodes are promising for high current and high brightness electron beam applications such as free-electron lasers and THz power devices.

  20. Electron beam collimation with a 40 000 tip metallic double-gate field emitter array and in-situ control of nanotip sharpness distribution

    Science.gov (United States)

    Helfenstein, P.; Guzenko, V. A.; Fink, H.-W.; Tsujino, S.

    2013-01-01

    The generation of highly collimated electron beams from a double-gate field emitter array with 40000 metallic tips and large collimation gate apertures is reported. Field emission beam measurements demonstrated the reduction of the beam envelope down to the array size by applying a negative potential to the on-chip gate electrode for the collimation of individual field emission beamlets. Owing to the optimized gate structure, the concomitant decrease of the emission current was minimal, leading to a net enhancement of the current density. Furthermore, a noble gas conditioning process was successfully applied to the double-gate device to improve the beam uniformity in-situ with orders of magnitude increase of the active emission area. The results show that the proposed double-gate field emission cathodes are promising for high current and high brightness electron beam applications such as free-electron lasers and THz power devices.

  1. Suppression of Divergence of Low Energy Ion Beams by Space Charge Neutralization with Low Energy Electrons Emitted from Field Emitter Arrays

    International Nuclear Information System (INIS)

    Suppression of divergence of low energy neon ion beam was experimentally demonstrated by neutralizing the space charge of ion beam with low energy electrons emitted from silicon field emitter arrays (Si-FEAs). Treatment of the FEAs with trifluoromethane plasma realized surface carbonization which was efficient to elongate the lifetime of the FEA and to improve the electron energy distribution. Together with the improvement of the performance of Si-FEA, we have developed a novel electron deceleration system to produce low energy electrons. A low energy neon ion beam was produced and the beam property was investigated with and without the electron supply from surface carbonized Si-FEA (Si:C-FEA). As a result, the divergence of the neon ion beam was largely suppressed with presence of the electrons.

  2. 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.

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

    International Nuclear Information System (INIS)

    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.

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

    CERN Document Server

    Schroeder, C B; Bulanov, S S; Chen, M; Esarey, E; Geddes, C G R; Vay, J -L; Yu, L -L; Leemans, W P

    2015-01-01

    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:Al2...

  5. 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.

  6. Development of a pepper-pot emittance meter for diagnostics of low-energy multiply charged heavy ion beams extracted from an ECR ion source

    Energy Technology Data Exchange (ETDEWEB)

    Nagatomo, T., E-mail: nagatomo@riken.jp; Kase, M.; Kamigaito, O.; Nakagawa, T. [Nishina Center for Accelerator Based Science, RIKEN, Wako, Saitama 351-0198 (Japan); Tzoganis, V. [Nishina Center for Accelerator Based Science, RIKEN, Wako, Saitama 351-0198 (Japan); Cockcroft Institute, Daresbury, Warrington WA4 4AD (United Kingdom); Department of Physics, University of Liverpool, Liverpool, Merseyside L69 3BX (United Kingdom)

    2016-02-15

    Several fluorescent materials were tested for use in the imaging screen of a pepper-pot emittance meter that is suitable for investigating the beam dynamics of multiply charged heavy ions extracted from an ECR ion source. SiO{sub 2} (quartz), KBr, Eu-doped CaF{sub 2}, and Tl-doped CsI crystals were first irradiated with 6.52-keV protons to determine the effects of radiation damage on their fluorescence emission properties. For such a low-energy proton beam, only the quartz was found to be a suitable fluorescent material, since the other materials suffered a decay in fluorescence intensity with irradiation time. Subsequently, quartz was irradiated with heavy {sup 12}C{sup 4+}, {sup 16}O{sup 4+}, and {sup 40}Ar{sup 11+} ions, but it was found that the fluorescence intensity decreased too rapidly to measure the emittance of these heavy-ion beams. These results suggest that a different energy loss mechanism occurs for heavier ions and for protons.

  7. Development of a pepper-pot emittance meter for diagnostics of low-energy multiply charged heavy ion beams extracted from an ECR ion source

    Science.gov (United States)

    Nagatomo, T.; Tzoganis, V.; Kase, M.; Kamigaito, O.; Nakagawa, T.

    2016-02-01

    Several fluorescent materials were tested for use in the imaging screen of a pepper-pot emittance meter that is suitable for investigating the beam dynamics of multiply charged heavy ions extracted from an ECR ion source. SiO2 (quartz), KBr, Eu-doped CaF2, and Tl-doped CsI crystals were first irradiated with 6.52-keV protons to determine the effects of radiation damage on their fluorescence emission properties. For such a low-energy proton beam, only the quartz was found to be a suitable fluorescent material, since the other materials suffered a decay in fluorescence intensity with irradiation time. Subsequently, quartz was irradiated with heavy 12C4+, 16O4+, and 40Ar11+ ions, but it was found that the fluorescence intensity decreased too rapidly to measure the emittance of these heavy-ion beams. These results suggest that a different energy loss mechanism occurs for heavier ions and for protons.

  8. An experimental approach to improve the Monte Carlo modelling of offline PET/CT-imaging of positron emitters induced by scanned proton beams.

    Science.gov (United States)

    Bauer, J; Unholtz, D; Kurz, C; Parodi, K

    2013-08-01

    We report on the experimental campaign carried out at the Heidelberg Ion-Beam Therapy Center (HIT) to optimize the Monte Carlo (MC) modelling of proton-induced positron-emitter production. The presented experimental strategy constitutes a pragmatic inverse approach to overcome the known uncertainties in the modelling of positron-emitter production due to the lack of reliable cross-section data for the relevant therapeutic energy range. This work is motivated by the clinical implementation of offline PET/CT-based treatment verification at our facility. Here, the irradiation induced tissue activation in the patient is monitored shortly after the treatment delivery by means of a commercial PET/CT scanner and compared to a MC simulated activity expectation, derived under the assumption of a correct treatment delivery. At HIT, the MC particle transport and interaction code FLUKA is used for the simulation of the expected positron-emitter yield. For this particular application, the code is coupled to externally provided cross-section data of several proton-induced reactions. Studying experimentally the positron-emitting radionuclide yield in homogeneous phantoms provides access to the fundamental production channels. Therefore, five different materials have been irradiated by monoenergetic proton pencil beams at various energies and the induced β(+) activity subsequently acquired with a commercial full-ring PET/CT scanner. With the analysis of dynamically reconstructed PET images, we are able to determine separately the spatial distribution of different radionuclide concentrations at the starting time of the PET scan. The laterally integrated radionuclide yields in depth are used to tune the input cross-section data such that the impact of both the physical production and the imaging process on the various positron-emitter yields is reproduced. The resulting cross-section data sets allow to model the absolute level of measured β(+) activity induced in the investigated

  9. Emittance of short-pulsed high-current ion beams formed from the plasma of the electron cyclotron resonance discharge sustained by high-power millimeter-wave gyrotron radiation

    Science.gov (United States)

    Razin, S.; Zorin, V.; Izotov, I.; Sidorov, A.; Skalyga, V.

    2014-02-01

    We present experimental results on measuring the emittance of short-pulsed (≤100 μs) high-current (80-100 mA) ion beams of heavy gases (Nitrogen, Argon) formed from a dense plasma of an ECR source of multiply charged ions (MCI) with quasi-gas-dynamic mode of plasma confinement in a magnetic trap of simple mirror configuration. The discharge was created by a high-power (90 kW) pulsed radiation of a 37.5-GHz gyrotron. The normalized emittance of generated ion beams of 100 mA current was (1.2-1.3) π mm mrad (70% of ions in the beams). Comparing these results with those obtained using a cusp magnetic trap, it was concluded that the structure of the trap magnetic field lines does not exert a decisive influence on the emittance of ion beams in the gas-dynamic ECR source of MCI.

  10. 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

  11. Future laser-accelerated proton beams at ELI-Beamlines as potential source of positron emitters for PET

    International Nuclear Information System (INIS)

    The development of novel compact PET radionuclide production systems is of great interest to promote the diffusion of PET diagnostics, especially in view of the continuous development of novel, fast and efficient, radiopharmaceutical methods of labeling. We studied the feasibility to produce clinically-relevant amounts of PET isotopes by means of laser-accelerated proton sources expected at the ELI-Beamlines facility where a PW, 30 fs, 10 Hz laser system will be available. The production yields of several positron emitters were calculated through the TALYS software, by taking into account three possible scenarios of broad proton spectra expected, with maximum energies ranging from about 8 MeV to 100 MeV. With the hypothesized proton fluencies, clinically-relevant amounts of radionuclides can be obtained, suitable to prepare single doses of radiopharmaceuticals exploiting modern fast and efficient labeling systems

  12. Future laser-accelerated proton beams at ELI-Beamlines as potential source of positron emitters for PET

    Science.gov (United States)

    Amato, E.; Italiano, A.; Margarone, D.; Pagano, B.; Baldari, S.; Korn, G.

    2016-04-01

    The development of novel compact PET radionuclide production systems is of great interest to promote the diffusion of PET diagnostics, especially in view of the continuous development of novel, fast and efficient, radiopharmaceutical methods of labeling. We studied the feasibility to produce clinically-relevant amounts of PET isotopes by means of laser-accelerated proton sources expected at the ELI-Beamlines facility where a PW, 30 fs, 10 Hz laser system will be available. The production yields of several positron emitters were calculated through the TALYS software, by taking into account three possible scenarios of broad proton spectra expected, with maximum energies ranging from about 8 MeV to 100 MeV. With the hypothesized proton fluencies, clinically-relevant amounts of radionuclides can be obtained, suitable to prepare single doses of radiopharmaceuticals exploiting modern fast and efficient labeling systems.

  13. Emittance Measurement in MICE

    OpenAIRE

    Hart, Terrence L.; Kaplan, Daniel M.

    2008-01-01

    Muon ionization cooling provides the only practical solution to prepare high-brilliance beams necessary for a neutrino factory or muon collider. The Muon Ionization Cooling Experiment (MICE), under development at the Rutherford Appleton Laboratory, is installing the first set of particle detectors ever built to measure to 0.1% the emittance of a 200 MeV/c or so muon beam in and out of a cooling cell, and thus measure the cooling cell's performance. Two identical "emittometers" (a precise scin...

  14. Efficient upconversion polymer-inorganic nanocomposite thin film emitters prepared by the double beam matrix assisted pulsed laser evaporation (DB-MAPLE)

    Science.gov (United States)

    Darwish, Abdalla M.; Burkett, Allan; Blackwell, Ashley; Taylor, Keylantra; Walker, Vernell; Sarkisov, Sergey; Koplitz, Brent

    2014-09-01

    We report on fabrication and investigation of optical and morphological properties of highly efficient (a quantum yield of 1%) upconversion polymer-inorganic nanocomposite thin film emitters prepared by the new technique of double beam matrix assisted pulsed laser evaporation (DB-MAPLE). Polymer poly(methyl methacrylate) (PMMA) host was evaporated on a silicon substrate using a 1064-nm pulsed laser beam using a target made of frozen (to the temperature of liquid nitrogen) solution of PMMA in chlorobenzene. Concurrently, the second 532-nm pulsed beam from the same laser was used to impregnate the polymer host with the inorganic nanoparticulate made of the rare earth upconversion compounds NaYF4: Yb3+, Er3+, NaYF4: Yb3+, Ho3+, and NaYF4: Yb3+, Tm3+. The compounds were initially synthesized using the wet process, baked, and compressed in solid pellet targets. The proposed DB-MAPLE method has the advantage of making highly homogeneous nanocomposite films with precise control of the doping rate due to the optimized overlapping of the plumes produced by the ablation of the organic and inorganic target with the infrared and visible laser beams respectively. X-ray diffraction, electron and atomic force microscopy, and optical fluorescence spectroscopy indicated that the inorganic nanoparticulate preserved its crystalline structure and upconversion properties (strong emission in green, red, and blue bands upon illumination with 980-nm laser diode) after being transferred from the target in the polymer nanocomposite film. The produced films can be used in applications varying from the efficiency enhancement of the photovoltaic cells, optical sensors and biomarkers to anti-counterfeit labels.

  15. Shielding in ungated field emitter arrays

    International Nuclear Information System (INIS)

    Cathodes consisting of arrays of high aspect ratio field emitters are of great interest as sources of electron beams for vacuum electronic devices. The desire for high currents and current densities drives the cathode designer towards a denser array, but for ungated emitters, denser arrays also lead to increased shielding, in which the field enhancement factor β of each emitter is reduced due to the presence of the other emitters in the array. To facilitate the study of these arrays, we have developed a method for modeling high aspect ratio emitters using tapered dipole line charges. This method can be used to investigate proximity effects from similar emitters an arbitrary distance away and is much less computationally demanding than competing simulation approaches. Here, we introduce this method and use it to study shielding as a function of array geometry. Emitters with aspect ratios of 102–104 are modeled, and the shielding-induced reduction in β is considered as a function of tip-to-tip spacing for emitter pairs and for large arrays with triangular and square unit cells. Shielding is found to be negligible when the emitter spacing is greater than the emitter height for the two-emitter array, or about 2.5 times the emitter height in the large arrays, in agreement with previously published results. Because the onset of shielding occurs at virtually the same emitter spacing in the square and triangular arrays, the triangular array is preferred for its higher emitter density at a given emitter spacing. The primary contribution to shielding in large arrays is found to come from emitters within a distance of three times the unit cell spacing for both square and triangular arrays

  16. Personnel exposure from positron emitters

    International Nuclear Information System (INIS)

    Positron emitters may contribute considerably to the radiation from induced radioactivity in accelerator environments. In most cases of thick radiating objects (magnets, shielding walls) the dose rate from gamma emitters, including the 511 keV annihilation photons from positron emitters, dominates the radiation field. Direct positron interaction in skin tissue and in the lens of the eye may be an important contribution to absorbed dose in cases of thin targets and beam separating septa. Results of calculations and measurements show, however, that the dose to the lens of the eye is limited by limitations placed on whole-body doses. Irradiation from positron emitters gives rise to about the same absorbed doses as those experienced in the case of an electron exposure. (author)

  17. Low emittance electron beam generation from a laser wakefield accelerator using two laser pulses with different wavelengths

    CERN Document Server

    Xu, X L; Zhang, C J; Li, F; Wan, Y; Hua, J F; Pai, C -H; Lu, W; Yu, P; Joshi, C; Mori, W B

    2014-01-01

    Ionization injection triggered by short wavelength laser pulses inside a nonlinear wakefield driven by a longer wavelength laser is examined via multi-dimensional particle-in-cell simulations. We find that very bright electron beams can be generated through this two-color scheme in either collinear propagating or transverse colliding geometry. For a fixed laser intensity $I$, lasers with longer/shorter wavelength $\\lambda$ have larger/smaller ponderomotive potential ($\\propto I \\lambda^2$). The two color scheme utilizes this property to separate the injection process from the wakefield excitation process. Very strong wakes can be generated at relatively low laser intensities by using a longer wavelength laser driver (e.g. a $10 \\micro\\meter$ CO$_2$ laser) due to its very large ponderomotive potential. On the other hand, short wavelength laser can produce electrons with very small residual momenta ($p_\\perp\\sim a_0\\sim \\sqrt{I}\\lambda$) inside the wake, leading to electron beams with very small normalized emit...

  18. Emittance Measurement in MICE

    CERN Document Server

    Hart, Terrence L

    2008-01-01

    Muon ionization cooling provides the only practical solution to prepare high-brilliance beams necessary for a neutrino factory or muon collider. The Muon Ionization Cooling Experiment (MICE), under development at the Rutherford Appleton Laboratory, is installing the first set of particle detectors ever built to measure to 0.1% the emittance of a 200 MeV/c or so muon beam in and out of a cooling cell, and thus measure the cooling cell's performance. Two identical "emittometers" (a precise scintillating-fiber tracker in solenoidal magnetic field and a 50 ps time-of-flight station) measure the six phase-space coordinates of each muon. Another TOF plane and two Cherenkov counters assure the purity of the incoming muon beam. A downstream electron/muon calorimeter eliminates contamination from decay electrons.

  19. Ultra Low Emittance Light Sources

    Energy Technology Data Exchange (ETDEWEB)

    Bengtsson,J.

    2008-06-23

    This paper outlines the special issues for reaching sub-nm emittance in a storage ring. Effects of damping wigglers, intra-beam scattering and lifetime issues, dynamic aperture optimization, control of optics, and their interrelations are covered in some detail. The unique choices for the NSLS-II are given as one example.

  20. Performance comparisons of low emittance lattices

    International Nuclear Information System (INIS)

    In this paper, the results of a performance analysis of several low emittance electron storage ring lattices provided by various members of the Lattice Working Group are presented. Altogether, four lattices were investigated. There are two different functions being considered for the low beam emittance rings discussed here. The first is to serve as a Damping Ring (DR), i.e., to provide the emittance damping required for a high energy linear collider. The second is to provide beams for a short wavelength Free Electron Laser (FEL), which is envisioned to operate in the wavelength region near 40 A

  1. Emittance growth due to dipole ripple and sextupole

    International Nuclear Information System (INIS)

    Ripple in the power supplies for storage ring magnets can have adverse effects on the circulating beams: orbit distortion and emittance growth from dipole ripple, tune modulation and dynamic aperture reduction from quadrupole ripple, etc. In this paper, we study the effects of ripple in the horizontal bending field of the SSC in the presence of nonlinearity, in particular, the growth in beam emittance

  2. Emittance growth due to dipole ripple and sextupole

    Energy Technology Data Exchange (ETDEWEB)

    Shih, H.J.; Ellison, J.A.; Syphers, M.J.; Newberger, B.S.

    1993-05-01

    Ripple in the power supplies for storage ring magnets can have adverse effects on the circulating beams: orbit distortion and emittance growth from dipole ripple, tune modulation and dynamic aperture reduction from quadrupole ripple, etc. In this paper, we study the effects of ripple in the horizontal bending field of the SSC in the presence of nonlinearity, in particular, the growth in beam emittance.

  3. Analysis of emittance growth of lattice with transverse and longitude coupling

    International Nuclear Information System (INIS)

    The emittance growing problem of non-correlating and non-coupling beam after passing through a lattice with transverse and longitude coupling was studied using linear transport theory. The results show that the beam effective emittance grows remarkably with the variation of initial conditions of beam after passing through the lattice. The related relations of the beam effective emittance growth and beam phase ellipse equations are given. (authors)

  4. A low-emittance lattice for SPEAR

    Science.gov (United States)

    Safranek, J.; Wiedemann, H.

    1992-08-01

    The design and implementation of a low emittance lattice for the SPEAR storage ring including measurements of the performance of the lattice are presented [J. Safranek, Ph.D. thesis, Stanford University, 1991]. The low emittance lattice is designed to optimize the performance of SPEAR as a synchrotron radiation source while keeping SPEAR hardware changes at a minimum. The horizontal emittance of the electron beam in the low emittance lattice is reduced by a factor of 4 from the previous lattice. This reduces the typical horizontal source size and divergence of the photon beams by a factor of 2 each and increases the photon beam brightness. At 3 GeV the horizontal emittance is 129π nm rad, which makes the low emittance lattice the lowest emittance, running synchrotron radiation source in the world in the 1.5 to 4.0 GeV energy range for the emittance scaled to 3 GeV. The measured vertical emittance was reduced to half that typically seen at SPEAR in the past. The brightness of the photon beams was further increased by reducing βy at the insertion devices to 1.1 m and reducing the energy dispersion at the insertion devices by more than a factor of 2 on average. The horizontal dispersion at the rf cavities was reduced by a factor of nearly 4 which gives much less problems with synchrobetatron resonances. The dynamic and physical apertures of the lattice are large, giving long beam lifetimes and easy injection of electrons. The measurements of the linear optics and intensity dependent phenomena gave reasonable agreement with the design. The overall performance of the machine was very good. Injection rates of 10 to 20 mA/min and larger were achieved routinely, and 100 mA total current was stored. Repeated ramping of stored beam from the injection energy of 2.3 GeV to the running energy of 3.0 GeV was achieved with very little beam loss. This low emittance configuration is expected to be the operating configuration for SPEAR starting in January 1992.

  5. Aberration Corrected Emittance Exchange

    CERN Document Server

    Nanni, Emilio A

    2015-01-01

    Full exploitation of emittance exchange (EEX) requires aberration-free performance of a complex imaging system including active radio-frequency (RF) elements which can add temporal distortions. We investigate the performance of an EEX line where the exchange occurs between two dimensions with normalized emittances which differ by orders of magnitude. The transverse emittance is exchanged into the longitudinal dimension using a double dog-leg emittance exchange setup with a 5 cell RF deflector cavity. Aberration correction is performed on the four most dominant aberrations. These include temporal aberrations that are corrected with higher order magnetic optical elements located where longitudinal and transverse emittance are coupled. We demonstrate aberration-free performance of emittances differing by 4 orders of magnitude, i.e. an initial transverse emittance of $\\epsilon_x=1$ pm-rad is exchanged with a longitudinal emittance of $\\epsilon_z=10$ nm-rad.

  6. Low emittance upgrade for CANDLE project

    CERN Document Server

    Zanyan, G S

    2015-01-01

    To improve the performance of CANDLE synchrotron light source and stay competitive with recently proposed low emittance upgrade programs in the world we have developed new low emittance lattices for CANDLE booster and storage ring. These lattices have been designed taking into account the new developments in magnet fabrication technology and the multi-bend achromat concept. The main design considerations, the linear and non-linear beam dynamics aspects of the modified lattices are presented.

  7. Calculated and measured emittance of sputter-type negative-ion source

    International Nuclear Information System (INIS)

    A method for calculating the beam current and emittance of a negative ion beam from a sputter-type source is described. Calculations are compared to measured emittance. The dependence of the emittance on ion source parameters such as cathode shape, exit aperture diameter, and cathode voltage is discussed

  8. Studies of emittance growth in the ATF

    International Nuclear Information System (INIS)

    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

  9. Tolerances for the vertical emittance in damping rings

    International Nuclear Information System (INIS)

    Future damping rings for linear colliders will need to have very small vertical emittances. In the limit of low beam current, the vertical emittance is primarily determined by the vertical dispersion and the betatron coupling. In this paper, the contributions to these effects from random misalignments are calculated and tolerances are derived to limit the vertical emittance with a 95% confidence level. 10 refs., 5 figs

  10. ETAII 6 MEV PEPPERPOT EMITTANCE MEASUREMENT

    Energy Technology Data Exchange (ETDEWEB)

    Paul, A C; Richardson, R; Weir, J

    2004-10-18

    We measured the beam emittance at the ETAII accelerator using a pepper-pot diagnostic at nominal parameters of 6 MeV and 2000 Amperes. During the coarse of these experiments, a ''new tune'' was introduced which significantly improved the beam quality. The source of a background pedestal was investigated and eliminated. The measured ''new tune'' emittance is {var_epsilon}= 8.05 {plus_minus} 0. 53 cm - mr or a normalized emittance of {var_epsilon}{sub n} = 943 {plus_minus} 63 mm - mr In 1990 the ETAII programmatic emphasis was on free electron lasers and the paramount parameter was whole beam brightness. The published brightness for ETAII after its first major rebuild was J = 1 - 3 x 10{sup 8} A/(m - rad){sup 2} at a current and energy of 1000-1400 Amperes and 2.5 MeV. The average normalized emittance derived from table 2 of that report is 864 mm-mr corresponding to a real emittance of 14.8 cm-mr.

  11. 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.

  12. Transverse emittance measurement at REGAE via a solenoid scan

    International Nuclear Information System (INIS)

    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.

  13. Theoretical study of transverse-longitudinal emittance coupling

    Energy Technology Data Exchange (ETDEWEB)

    Qin, H; Davidson, R C; Chung, M; Barnard, J J; Wang, T F

    2011-04-14

    The effect of a weakly coupled periodic lattice in terms of achieving emittance exchange between the transverse and longitudinal directions is investigated using the generalized Courant-Snyder theory for coupled lattices. Recently, the concept and technique of transverse-longitudinal emittance coupling have been proposed for applications in the Linac Coherent Light Source and other free-electron lasers to reduce the transverse emittance of the electron beam. Such techniques can also be applied to the driver beams for the heavy ion fusion and beam-driven high energy density physics, where the transverse emittance budget is typically tighter than the longitudinal emittance. The proposed methods consist of one or several coupling components which completely swap the emittances of one of the transverse directions and the longitudinal direction at the exit of the coupling components. The complete emittance exchange is realized in one pass through the coupling components. In the present study, we investigate the effect of a weakly coupled periodic lattice in terms of achieving emittance exchange between the transverse and longitudinal directions. A weak coupling component is introduced at every focusing lattice, and we would like to determine if such a lattice can realize the function of emittance exchange.

  14. Experimental study of coherent synchrotron radiation in the emittance exchange line at the A0-photoinjector

    CERN Document Server

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

    2012-01-01

    Next generation accelerators will require a high current, low emittance beam with a low energy spread. Such accelerators will employ advanced beam conditioning systems such as emittance exchangers to manipulate high brightness beams. One of the goals of the Fermilab A0 photoinjector is to investigate the transverse to longitudinal emittance exchange principle. Coherent synchrotron radiation could limit high current operation of the emittance exchanger. In this paper, we report on the preliminary experimental and simulation study of the coherent synchroton radiation (CSR) in the emittance exchange line at the A0 photoinjector.

  15. Experimental study of coherent synchrotron radiation in the emittance exchange line at the A0-photoinjector

    Energy Technology Data Exchange (ETDEWEB)

    Thangaraj, Jayakar C.T.; Thurman-Keup, R.; Johnson, A.; Lumpkin, A.H.; Edwards, H.; Ruan, J.; Santucci, J.; Sun, Y.E.-; Church, M.; /Fermilab; Piot, P.; /Fermilab /Northern Illinois U.

    2010-08-01

    Next generation accelerators will require a high current, low emittance beam with a low energy spread. Such accelerators will employ advanced beam conditioning systems such as emittance exchanger to manipulate high brightness beams. One of the goals of the Fermilab A0 photoinjector is to investigate the transverse to longitudinal emittance exchange principle. Coherent synchrotron radiation could limit high current operation of the emittance exchanger. In this paper, we report on the preliminary experimental and simulation study of the coherent synchroton radiation (CSR) in the emittance exchange line at A0 photoinjector.

  16. Modular low-voltage electron emitters

    International Nuclear Information System (INIS)

    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

  17. 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.

  18. Modeling and analysis of all the positron emitters simulation steps generated during the treatment phase in proton-therapy - from the beam to the PET camera - for the follow-up of the irradiations

    International Nuclear Information System (INIS)

    The proton-therapy is an innovative technique for cancer treatment in critical areas, such as the eye or the head. Even though the interaction of protons with human tissues is a well-known physical phenomenon which gives rise to the proton-therapy, there are uncertainties on the proton trajectory due to heterogeneities in the irradiated tissue, the calculation of the beam parameters in the planning treatment affects the theoretical benefits of the protons and the chosen dose delivery process. Thus, methods for irradiation quality control have been suggested. Most of them rely on utilizing the mapping of the positron emitters generated during the irradiation. They are detectable and quantifiable thanks to the use of the PET (positron emitter tomography), a medical imaging technique mainly used for the cancer expansion assessment. PET acquisitions were proposed and then realized on phantoms and patients after proton-therapy. The quality control relies on comparing the measured radioactive distribution to the simulated β+ distribution. The modeling of the positron activity generated by protons in the irradiated area can be divided into three steps: the simulation of the proton beam, the modeling of the proton interactions in the irradiated object and the modeling of the PET acquisition. Different ways of simulating these steps are possible. This PhD work suggests different ways of modeling the three steps and evaluates theirs benefits for the irradiation quality control. We have restrained our evaluation to the verification of the proton range and to the uncertainties related to the proton range. This research work utilizes on irradiations in homogenous and inhomogeneous areas in a head model. We have compared the uncertainties on the proton range measured thanks to the following β+ distributions: 1) A β+ distribution obtained by modeling the irradiation with a proton beam simulated analytically and simulated using the complete Monte Carlo method; 2) A Monte Carlo

  19. Preparation of an emittance transfer experiment

    CERN Document Server

    Xiao, C; Groening, L; Leibrock, H; Maier, M

    2012-01-01

    Flat beams feature unequal emittances in the horizontal and vertical phase space. Those beams were created successfully in lepton machines. Although a number of applications will profit also from flat hadron beams, to our knowledge they have never been created systematically. Multi-turn injection schemes, spectrometers, and colliders will directly benefit from those beams. The present paper covers the preparation of the experimental proof of principle for flat hadron beam creation in a beam transport section. Detailed simulations of the experiment, based on charge state stripping inside of a solenoid [L. Groening, Phys. Rev. ST Accel. Beams 14, 064201 (2011)], are performed. The matrix formalism was benchmarked with tracking through three-dimensional magnetic field maps of solenoids. An error analysis targeting at investigation of the impact of machine errors on the round-to-flat beam transformation has been performed. The remarkable flexibility of the set-up w.r.t. decoupling is addressed, as it can provide ...

  20. High brightness symmetric emittance rf photoinjector preliminary design report

    International Nuclear Information System (INIS)

    A preliminary design for a high bunch charge (8 nC), low emittance (z = 1 mm. Electrical and beam dynamical aspects of the photoinjector design are presented. A description of the proposed experimental program is included

  1. Recent developments of low-emittance electron gun for accelerator

    International Nuclear Information System (INIS)

    Recent developments of low-emittance electron guns for accelerator are reviewed. In the accelerator field, DC biased triode thermionic gun (Pierce type gun) has been widely used and is still conventional. On the other hand, because of strong demands on the high brightness electron beam by FEL and other advanced accelerator concepts based on linear accelerator, the low emittance beam generation becomes one of the most important issue in the accelerator science. The R and D effort is 'accelerated' by two technological innovations, photo-cathode and RF gun. They made a large improvement on the beam emittance. After the explanations on the technical and physical aspects of the low emittance electron beam generation, advanced electron sources for accelerators are reviewed. (author)

  2. CSR-induced emittance growth in achromats: Linear formalism revisited

    Energy Technology Data Exchange (ETDEWEB)

    Venturini, M.

    2015-09-11

    We review the R-matrix formalism used to describe Coherent Synchrotron Radiation (CSR)-induced projected emittance growth in electron beam transport lines and establish the connection with a description in terms of the dispersion-invariant function.

  3. CSR-induced emittance growth in achromats: Linear formalism revisited

    Science.gov (United States)

    Venturini, M.

    2015-09-01

    We review the R-matrix formalism used to describe Coherent Synchrotron Radiation (CSR)-induced projected emittance growth in electron beam transport lines and establish the connection with a description in terms of the dispersion-invariant function.

  4. Emittance growth due to dipole ripple and sextupole

    International Nuclear Information System (INIS)

    Ripple in the power supplies for storage ring magnets can have adverse effects on the circulating beams: orbit distortion and emittance growth from dipole ripple, tune modulation and dynamic aperture reduction from quadrupole ripple, etc. In this paper, the authors study the effects of ripple in the horizontal bending field of the SSC in the presence of nonlinearity, in particular, the growth in beam emittance

  5. Emittance compensation of CW DC-gun photoinjector

    International Nuclear Information System (INIS)

    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)

  6. Muon Cooling—emittance exchange

    Science.gov (United States)

    Parsa, Zohreh

    2001-05-01

    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.

  7. Direct Observation of Ultralow Vertical Emittance using a Vertical Undulator

    Energy Technology Data Exchange (ETDEWEB)

    Wootton, Kent

    2015-09-17

    In recent work, the first quantitative measurements of electron beam vertical emittance using a vertical undulator were presented, with particular emphasis given to ultralow vertical emittances [K. P. Wootton, et al., Phys. Rev. ST Accel. Beams, 17, 112802 (2014)]. Using this apparatus, a geometric vertical emittance of 0.9 ± 0.3 pm rad has been observed. A critical analysis is given of measurement approaches that were attempted, with particular emphasis on systematic and statistical uncertainties. The method used is explained, compared to other techniques and the applicability of these results to other scenarios discussed.

  8. Emittance Measurement with Upgraded RF Gun System at SPring-8

    CERN Document Server

    Mizuno, Akihiko; Hanaki, Hirofumi; Taniuchi, Tsutomu; Tomizawa, Hiromitsu; Uesaka, Mitsuru

    2005-01-01

    A single cell S-band RFgun has been developed at the SPring-8 since 1996. The minimum normalized beam emittance, measured with double slits' scanning method in 2002, was 2.3 pi mm mrad at the exit of the gun cavity with charge of 0.1 nC/bunch. In 2004, we installed a following accelerator structure to investigate beam behavior of the whole injector system. In this paper, we report emittance measurement results of upgraded system, using variable quadrupole magnet method. The minimum emittance of 2.0 pi mm mrad with a net charge of 0.14 nC/bunch were able to be measured.

  9. Quadrupole Transfer Function for Emittance Measurement

    CERN Document Server

    Cameron, Peter; Jansson, Andreas; Tan, Cheng-Yang

    2008-01-01

    Historically the use of the quadrupole moment measurement has been impeded by the requirement for large dynamic range, as well as measurement sensitivity to beam position. We investigate the use of the transfer function technique [1-3] in combination with the sensitivity and 160dB revolution line rejection of the direct diode detection analog front end [4] to open the possibility of an emittance diagnostic that may be implemented without operational complication, quasi- parasitic to the operation of existing tune measurement systems. Such a diagnostic would be particularly useful as an emittance monitor during acceleration ramp development in machines like RHIC and the LHC.

  10. Longitudinal emittance measurements at REX-ISOLDE

    CERN Document Server

    Fraser, M A; Jones, R.M.; Jones, R M; Pasini, M; Posocco, P A; Voulot, D; Wenander, F

    2012-01-01

    We report on measurements of the longitudinal emittance at the Radioactive ion beam EXperiment (REX) at ISOLDE, CERN. The rms longitudinal emittance was measured as 0.34 ± 0.08 π ns keV/u at the output of the RFQ and as 0.36 ± 0.04π ns keV/u in front of the third 7-gap split-ring resonator (7G3) using the three-gradient technique; systematic errors are not included but are estimated at approximately 10%. The 86% emittance was measured a factor of approximately 4.4 times larger than the rms emittance at 1.48 ± 0.2 and 1.55 ± 0.12π ns keV/u at the RFQ and 7G3, respectively. The REX switchyard magnet was used as a spectrometer to analyse the energy spread of the beam as it was manipulated by varying the voltage of the rebuncher (ReB) and 7G3 cavities operating at non-accelerating phases. The transfer matrix for a multi-gap bunching cavity is derived and suitably truncated to allow for the accurate reconstruction of the beam parameters from measurement. The technique for measuring the energy spread was rig...

  11. The DIORAMA Neutron Emitter

    Energy Technology Data Exchange (ETDEWEB)

    Terry, James Russell [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-05-05

    Emission of neutrons in a given event is modeled by the DioramaEmitterNeutron object, a subclass of the abstract DioramaEmitterModule object. The GenerateEmission method of this object is the entry point for generation of a neutron population for a given event. Shown in table 1, this method requires a number of parameters to be defined in the event definition.

  12. Performance comparisons of low emittance lattices

    International Nuclear Information System (INIS)

    The results of a performance analysis of four low emittance electron storage ring lattices provided to the authors by various members of the Lattice Working Group is presented. Altogether, four lattices were investigated. The beam energies of the four lattices are, respectively, 1.1, 2, 3, 4 GeV). A brief summary of the lattice parameters relevant to this study is given. The performance issues studied include an estimation of the longitudinal emittance expected for each lattice based on the effects of the longitudinal microwave instability, an estimation of the transverse emittance growth of the (required) dense bunches under the influence of intrabeam scattering (IBS), and an estimate of the Touschek lifetime. The analysis described here has been carried out with the LBL accelerator physics code ZAP

  13. Cascaded injection resonator for coherent beam combining of laser arrays

    Science.gov (United States)

    Kireev, Vassili [Sunnyvale, CA; Liu, Yun; Protopopescu, Vladimir [Knoxville, TN; Braiman, Yehuda [Oak Ridge, TN

    2008-10-21

    The invention provides a cascaded injection resonator for coherent beam combining of laser arrays. The resonator comprises a plurality of laser emitters arranged along at least one plane and a beam sampler for reflecting at least a portion of each laser beam that impinges on the beam sampler, the portion of each laser beam from one of the laser emitters being reflected back to another one of the laser emitters to cause a beam to be generated from the other one of the laser emitters to the beam reflector. The beam sampler also transmits a portion of each laser beam to produce a laser output beam such that a plurality of laser output beams of the same frequency are produced. An injection laser beam is directed to a first laser emitter to begin a process of generating and reflecting a laser beam from one laser emitter to another laser emitter in the plurality. A method of practicing the invention is also disclosed.

  14. Tuning the Magnetic Transport of an Induction LINAC using Emittance

    Energy Technology Data Exchange (ETDEWEB)

    Houck, T L; Brown, C G; Ong, M M; Paul, A C; Wargo, P E; Zentler, J M

    2006-08-11

    The Lawrence Livermore National Laboratory Flash X-Ray (FXR) machine is a linear induction accelerator used to produce a nominal 18 MeV, 3 kA, 65 ns pulse width electron beam for hydrodynamic radiographs. A common figure of merit for this type of radiographic machine is the x-ray dose divided by the spot area on the bremsstrahlung converter where a higher FOM is desired. Several characteristics of the beam affect the minimum attainable x-ray spot size. The most significant are emittance (chaotic transverse energy), chromatic aberration (energy variation), and beam motion (transverse instabilities and corkscrew motion). FXR is in the midst of a multi-year optimization project to reduce the spot size. This paper describes the effort to reduce beam emittance by adjusting the fields of the transport solenoids and position of the cathode. If the magnetic transport is not correct, the beam will be mismatched and undergo envelope oscillations increasing the emittance. We measure the divergence and radius of the beam in a drift section after the accelerator by imaging the optical transition radiation (OTR) and beam envelope on a foil. These measurements are used to determine an emittance. Relative changes in the emittance can be quickly estimated from the foil measurements allowing for an efficient, real-time study. Once an optimized transport field is determined, the final focus can be adjusted and the new x-ray spot measured. A description of the diagnostics and analysis is presented.

  15. Tuning the Magnetic Transport of an Induction LINAC using Emittance

    International Nuclear Information System (INIS)

    The Lawrence Livermore National Laboratory Flash X-Ray (FXR) machine is a linear induction accelerator used to produce a nominal 18 MeV, 3 kA, 65 ns pulse width electron beam for hydrodynamic radiographs. A common figure of merit for this type of radiographic machine is the x-ray dose divided by the spot area on the bremsstrahlung converter where a higher FOM is desired. Several characteristics of the beam affect the minimum attainable x-ray spot size. The most significant are emittance (chaotic transverse energy), chromatic aberration (energy variation), and beam motion (transverse instabilities and corkscrew motion). FXR is in the midst of a multi-year optimization project to reduce the spot size. This paper describes the effort to reduce beam emittance by adjusting the fields of the transport solenoids and position of the cathode. If the magnetic transport is not correct, the beam will be mismatched and undergo envelope oscillations increasing the emittance. We measure the divergence and radius of the beam in a drift section after the accelerator by imaging the optical transition radiation (OTR) and beam envelope on a foil. These measurements are used to determine an emittance. Relative changes in the emittance can be quickly estimated from the foil measurements allowing for an efficient, real-time study. Once an optimized transport field is determined, the final focus can be adjusted and the new x-ray spot measured. A description of the diagnostics and analysis is presented

  16. Space Charge Effects in Rectilinear Motion Emittance

    CERN Document Server

    Chen, C

    2000-01-01

    This report summarizes the presentations and discussions over a wide range of topics in Working Group I at the Second ICFA Advanced Accelerator Workshop on Physics of High-Brightness Beams held at University of California at Los $9 Angeles (UCLA), November 9-12, 1999. Latest developments towards to a better understanding of high-brightness photoinjectors were reported. The design and commissioning of the Los Alamos National Laboratory (LANL) Low-Energy $9 Demonstration Accelerator (LEDA) Radio-Frequency Quadrupole (RFQ) were reported. The problem of beam halo formation was discussed in both beam transport systems and the SLAC 50 MW 11.4 GHz periodic permanent magnet (PPM) focusing $9 klystron amplifier. A new class of corkscrewing elliptic beam equilibria was reported, and applications of such novel beam equilibria in controlling of charge-density and velocity fluctuations, beam halo formation and emittance $9 growth were discussed. Pattern formation in proton rings was also discussed.

  17. Sectional and projectional emittance measurements a

    International Nuclear Information System (INIS)

    For many applications of ion sources the quality of the generated ion beam plays an increasingly important role. Ion sources consist of the plasma generator and the extraction system. Both parts can, due to high ion temperature or various aberrations, contribute to a degrading of the beam quality. Though the beam quality is determined by many more factors, the transverse motion of the particles certainly is one of the important parameters. Knowledge of it can be obtained by an emittance measurement. This is best done in a four-dimensional phase space, yielding a density distribution as function of the transverse spatial and momentum coordinates. Often, however, due to practical considerations, only two dimensions of the four-dimensional open-quote open-quote trace space close-quote close-quote are being measured. This two-dimensional data can be obtained as a section or as a projection of the four-dimensional trace space, where both methods have their merits. Projectional emittance measurements can usually be performed much easier and quicker, but by the projection of the four-dimensional space onto a two-dimensional plane information is lost. And although not all the particles of the beam are represented in a section of trace space, here aberrative distortions of the emittance can be seen most clearly and allow an easier comparison to numerically obtained data. The advantages and disadvantages of both methods are discussed. Numerical and experimental examples are presented. copyright 1996 American Institute of Physics

  18. Cancer from internal emitters

    International Nuclear Information System (INIS)

    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 226Ra or medical injections of 224Ra, and thyroid cancer from exposures to iodine radionuclides in the environment or for medical purposes

  19. RFI emitter location techniques

    Science.gov (United States)

    Rao, B. L. J.

    1973-01-01

    The possibility is discussed of using Doppler techniques for determining the location of ground based emitters causing radio frequency interference with low orbiting satellites. An error analysis indicates that it is possible to find the emitter location within an error range of 2 n.mi. The parameters which determine the required satellite receiver characteristic are discussed briefly along with the non-real time signal processing which may by used in obtaining the Doppler curve. Finally, the required characteristics of the satellite antenna are analyzed.

  20. PENCIL LEAD FIELD EMITTER

    OpenAIRE

    Khairnar, R.; Joag, D.

    1989-01-01

    Field electron emission from 2H and HB grades of pencil lead has been studied. The pencil lead field emitter is found to obey the Fowler-Nordheim characteristics. The emission current fluctuations are found to increase with the residual gas pressure and the emission current. The current density of the order of 106 amp/cm2 could be drawn from these emitters. The emission stability over the operation of six hours has been found to be reasonably good. The field ion microscopy of the 2H and HB gr...

  1. Emittance growths in resonance crossing at FFAGs

    Energy Technology Data Exchange (ETDEWEB)

    Ng, K.Y.; /Fermilab; Pang, X.; Wang, F.; Wang, X.; Lee, S.Y.; /Indiana U.

    2007-10-01

    Scaling laws of the emittance growth for a beam crossing the 6th-order systematic space-charge resonances and the random-octupole driven 4th-order resonance are obtained by numerical multi-particle simulations. These laws can be important in setting the minimum acceleration rate and maximum tolerable resonance strength for the design of non-scaling fixed-field alternating gradient accelerators.

  2. Emittance growth in the DARHT Axis-II Downstream Transport

    Energy Technology Data Exchange (ETDEWEB)

    Ekdahl, Jr., Carl August [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Schulze, Martin E. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-04-14

    Using a particle-in-cell (PIC) code, we investigated the possibilities for emittance growth through the quadrupole magnets of the system used to transport the high-current electron beam from an induction accelerator to the bremsstrahlung converter target used for flash radiography. We found that even highly mismatched beams exhibited little emittance growth (< 6%), which we attribute to softening of their initial hard edge current distributions. We also used this PIC code to evaluate the accuracy of emittance measurements using a solenoid focal scan following the quadrupole magnets. If the beam is round after the solenoids, the simulations indicate that the measurement is highly accurate, but it is substantially inaccurate for elliptical beams

  3. Low-emittance tuning at the Cornell Electron Storage Ring

    CERN Document Server

    Shanks, James; Sagan, David

    2013-01-01

    In 2008 the Cornell Electron/Positron Storage Ring (CESR) was reconfigured from an electron/positron collider to serve as a testbed for the International Linear Collider (ILC) damping rings. One of the primary goals of the CESR Test Accelerator (CesrTA) project is to develop low emittance tuning techniques to achieve sub-10pm geometric vertical emittance at 2.085 GeV. This paper discusses the tuning methods used at CesrTA to achieve low-emittance conditions. A minimum vertical emittance of 8.7 +2.9/-3.4(sys) +/-0.2(stat) pm has been achieved at 2.085 GeV. In various configurations and beam energies the correction technique routinely achieves vertical emittance <15 pm after correction. Beam-based measurement and correction requires about 15 minutes. Simulations modeling the effects of magnet misalignments, BPM errors, and emittance correction algorithm suggest the residual vertical emittance measured at the conclusion of the tuning procedure is dominated by sources other than optics errors and misalignments...

  4. Optimization of the emittance of electrons (positrons) storage rings

    International Nuclear Information System (INIS)

    An important parameter of the source characteristics of a synchrotron radiation facility, is the beam emittance. The general structure presently adopted, is of the achromatic arc, or adapted dispersion type. This structure allows analytical treatment of dispersion and β function in the arcs, and then, the minimization of the dimension invariant. Practical formulae are given, allowing scaling of momentum compaction factor, minimum emittance limit and β value in the magnets. Limitations in chromaticity correction possibilities are also discussed

  5. Study of ultra-low emittance design for SPEAR3

    Energy Technology Data Exchange (ETDEWEB)

    Wang, M. -H.; Huang, X.; Safranek, J.; /SLAC

    2015-09-17

    Since its 2003 construction, the SPEAR3 synchrotron light source at SLAC has continuously improved its performance by raising beam current, top-off injection, and smaller emittance. This makes SPEAR3 one of the most productive light sources in the world. Now, to further enhance the performance of SPEAR3, we are looking into the possibility of converting SPEAR3 to an ultra-low emittance storage ring within its site constraint.

  6. Sharpening of field emitter tips using high-energy ions

    Science.gov (United States)

    Musket, Ronald G.

    1999-11-30

    A process for sharpening arrays of field emitter tips of field emission cathodes, such as found in field-emission, flat-panel video displays. The process uses sputtering by high-energy (more than 30 keV) ions incident along or near the longitudinal axis of the field emitter to sharpen the emitter with a taper from the tip or top of the emitter down to the shank of the emitter. The process is particularly applicable to sharpening tips of emitters having cylindrical or similar (e.g., pyramidal) symmetry. The process will sharpen tips down to radii of less than 12 nm with an included angle of about 20 degrees. Because the ions are incident along or near the longitudinal axis of each emitter, the tips of gated arrays can be sharpened by high-energy ion beams rastered over the arrays using standard ion implantation equipment. While the process is particularly applicable for sharpening of arrays of field emitters in field-emission flat-panel displays, it can be effectively utilized in the fabrication of other vacuum microelectronic devices that rely on field emission of electrons.

  7. High-current lanthanum-hexaboride electron emitter for a quasi-stationary arc plasma generator

    Energy Technology Data Exchange (ETDEWEB)

    Davydenko, V. I., E-mail: V.I.Davydenko@inp.nsk.su; Ivanov, A. A., E-mail: A.A.Ivanov@inp.nsk.su; Shul’zhenko, G. I. [Russian Academy of Sciences, Budker Institute of Nuclear Physics, Siberian Branch (Russian Federation)

    2015-11-15

    A high-current electron emitter on the basis of lanthanum hexaboride is developed for quasi-stationary arc plasma generators of ion sources. The emitter consists of a set of LaB{sub 6} washers interleaved with washers made of thermally extended graphite. The emitter is heated by the current flowing through the graphite washers. The thermal regime of emitter operation during plasma generation is considered. The emitter has been successfully used in the ion sources of the diagnostic injectors of fast hydrogen atomic beams.

  8. Study of Abnormal Vertical Emittance Growth in ATF Extraction Line

    Energy Technology Data Exchange (ETDEWEB)

    Alabau, M.; Faus-Golfe, A.; /Valencia U., IFIC; Alabau, M.; Bambade, P.; Brossard, J.; Le Meur, G.; Rimbault, C.; Touze, F.; /Orsay, LAL; Angal-Kalinin, D.; Jones, J.K.; /Daresbury; Appleby, R.; Scarfe, A.; /Manchester U.; Kuroda, S.; /KEK, Tsukuba; White, G.R.; Woodley, M.; /SLAC; Zimmermann, F.; /CERN

    2011-11-04

    Since several years, the vertical beam emittance measured in the Extraction Line (EXT) of the Accelerator Test Facility (ATF) at KEK, that will transport the electron beam from the ATF Damping Ring (DR) to the future ATF2 Final Focus beam line, is significantly larger than the emittance measured in the DR itself, and there are indications that it grows rapidly with increasing beam intensity. This longstanding problem has motivated studies of possible sources of this anomalous emittance growth. One possible contribution is non-linear magnetic fields in the extraction region experimented by the beam while passing off-axis through magnets of the DR during the extraction process. In this paper, simulations of the emittance growth are presented and compared to observations. These simulations include the effects of predicted non-linear field errors in the shared DR magnets and orbit displacements from the reference orbit in the extraction region. Results of recent measurements using closed orbit bumps to probe the relation between the extraction trajectory and the anomalous emittance growth are also presented.

  9. Frozen Beams

    CERN Document Server

    Okamoto, Hiromi

    2005-01-01

    In general, the temperature of a charged particle beam traveling in an accelerator is very high. Seen from the rest frame of the beam, individual particles randomly oscillate about the reference orbit at high speed. This internal kinetic energy can, however, be removed by introducing dissipative interactions into the system. As a dissipative process advances, the beam becomes denser in phase space or, in other words, the emittance is more diminished. Ideally, it is possible to reach a "zero-emittance" state where the beam is Coulomb crystallized. The space-charge repulsion of a crystalline beam just balances the external restoring force provided by artificial electromagnetic elements. In this talk, general discussion is made of coasting and bunched crystalline beams circulating in a storage ring. Results of molecular dynamics simulations are presented to demonstrate the dynamic nature of various crystalline states. A possible method to approach such an ultimate state of matter is also discussed.

  10. A method to measure the nonlinear force caused emittance growth in a RF photoinjector

    Institute of Scientific and Technical Information of China (English)

    Li Zheng-Hong; Yang Zhen-Ping

    2006-01-01

    Based on the multi-slit method, a new method is introduced to measure the non linear force caused emittance growth in a RF photoinjector. It is possible to reconstruct the phase space of a beam under some conditions by the multi-slit method. Based on the reconstructed phase space, besides the emittance, the emittance growth from the distortion of the phase space can also be measured. The emittance growth results from the effects of nonlinear force acting on electron, which is very important for the high quality beam in a RF photoinjector.

  11. 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

  12. 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).

  13. Emittance measurements results with upgraded setup at PITZ

    Energy Technology Data Exchange (ETDEWEB)

    Vashchenko, Grygorii; Asova, Galina; Gross, Matthias; Hakobyan, Levon; Isaev, Igor; Ivanisenko, Yevgeniy; Khojoyan, Martin; Klemz, Guido; Krasilnikov, Mikhail; Mahgoub, Mahmoud; Malyutin, Dmitriy; Otevrel, Marek; Petrosyan, Bagrat; Riechter, Dieter; Rimjaem, Sakhorn; Shapovalov, Andrey; Stephan, Frank [DESY, Zeuthen (Germany); Nozdrin, Mikhail [JINR, Dubna (Russian Federation); Templin, Horst-Ingo; Will, Ingo [MBI, Berlin (Germany)

    2012-07-01

    The photo injector test facility at DESY, Zeuthen site, PITZ develops and characterizes photoelectron sources for linac driven free electron lasers (FELs) such as FLASH and the European XFEL. The main goal of the PITZ is to obtain electron beams with low transverse normalize emittance which is necessary for the successful operation of SASE FEL. Major parts of the facility - gun and booster cavities, photocathode laser system were upgraded in 2010 in order to improve the photo injector performance. A slit technique is used at PITZ to reconstruct the transverse phase space of the electron beam. Many machine parameters were tuned to optimize the beam emittance for a wide range of the bunch charge - from 20 pC to 2 nC. Measured emittance depending on various machine parameters like a gun launching phase, booster gradient, laser spot size on the cathode and main solenoid current is presented.

  14. Directional Thermal Emitter Simulation

    OpenAIRE

    Dhaka, Shailja; Sakr, Enas Said; Bermel, Peter

    2015-01-01

    The development of renewable energy sources has attracted increasing interest because of negative externalities associated with fossil fuel use. Thermophotovoltaics is a promising technology, in which a thermal emitter radiates photons which are directly converted into electricity using a photovoltaic diode. However, blackbody emission includes a broad range of wavelengths, but only higher energy photons can be converted into electricity. Thus, tailoring the selectivity of thermal emission is...

  15. 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

  16. Measurements of the transverse emittance at the VUV-FEL

    International Nuclear Information System (INIS)

    The Tesla test facility (TTF) linear accelerator (linac) at DESY has been extended to drive a new Free Electron Laser facility (VUV-FEL) in the wavelength range from the vacuum-ultraviolet (VUV) to soft X-rays. With the upgraded photo injector and increased electron beam energy up to 1 GeV, wavelengths down to 6 nm can be achieved. During the commissioning phase of the VUV-FEL the emphasis is on lasing with a wavelength of 30 nm. A high quality electron beam is required for the lasing process. At the VUV-FEL the design values are 2 mm mrad normalized transverse emittance, 2500 A peak current, and 0.1% energy spread. In order to understand and optimize the electron beam, precise measurements of the beam properties are essential. In this diploma thesis, measurements of the transverse emittance during the commissioning of the VUV-FEL are presented. The transverse beam distribution is measured using optical transition radiation at four positions along the linac. The emittance is determined from the measured distributions using two methods: a fit of the Twiss parameters together with the emittance to the measured beam sizes, and as a second method, the tomographic reconstruction of the phase space density distributions using the Maximum Entropy Algorithm. (orig.)

  17. An ultracold low emittance electron source

    CERN Document Server

    Xia, G; Murray, A J; Bellan, L; Bertsche, W; Appleby, R B; Mete, O; Chattopadhyay, S

    2014-01-01

    Ultracold atom-based electron sources have recently been proposed as an alternative to the conventional photo-injectors or thermionic electron guns widely used in modern particle accelerators. The advantages of ultracold atom-based electron sources lie in the fact that the electrons extracted from the plasma (created from near threshold photo-ionization of ultracold atoms) have a very low temperature, i.e. down to tens of Kelvin. Extraction of these electrons has the potential for producing very low emittance electron bunches. These features are crucial for the next generation of particle accelerators, including free electron lasers, plasma-based accelerators and future linear colliders. The source also has many potential direct applications, including ultrafast electron diffraction (UED) and electron microscopy, due to its intrinsically high coherence. In this paper, the basic mechanism of ultracold electron beam production is discussed and our new research facility for an ultracold, low emittance electron s...

  18. A Resonant Cavity for Single-Shot Emittance Measurement

    CERN Document Server

    Kim, J S; Whittum, D H; Miller, R H; Tantawi, S G; Weidemann, A W

    2002-01-01

    We present a non-invasive, resonant cavity based approach to beam emittance measurement of a shot-to-shot non-circular beam pulse of multi-bunches. In a resonant cavity, desired field components can be enhanced up to Q_L_lambda/pi, where Q_L_lambda is the loaded Q of the resonance mode lambda, when the cavity resonant mode matches with the beam operating frequency. In particular, a Quad-cavity, with its quadrupole mode at beam operating frequency, extracts the beam quad-moment exclusively, utilizing the symmetry of the cavity and some simple networks to suppress common modes. Six successive beam quadrupole moment measurements, performed at different betatron phases in a linear transport system, allow us to determine the beam emittance, i.e., the beam size and shape in the beam's phase space. One measurement alone provides the rms-beam size if the beam position is given, for instance, by nearby beam-position-monitors. This paper describes the basic design and analysis of a Quad-cavity beam monitoring system.

  19. Localization of Narrowband Single Photon Emitters in Nanodiamonds.

    Science.gov (United States)

    Bray, Kerem; Sandstrom, Russell; Elbadawi, Christopher; Fischer, Martin; Schreck, Matthias; Shimoni, Olga; Lobo, Charlene; Toth, Milos; Aharonovich, Igor

    2016-03-23

    Diamond nanocrystals that host room temperature narrowband single photon emitters are highly sought after for applications in nanophotonics and bioimaging. However, current understanding of the origin of these emitters is extremely limited. In this work, we demonstrate that the narrowband emitters are point defects localized at extended morphological defects in individual nanodiamonds. In particular, we show that nanocrystals with defects such as twin boundaries and secondary nucleation sites exhibit narrowband emission that is absent from pristine individual nanocrystals grown under the same conditions. Critically, we prove that the narrowband emission lines vanish when extended defects are removed deterministically using highly localized electron beam induced etching. Our results enhance the current understanding of single photon emitters in diamond and are directly relevant to fabrication of novel quantum optics devices and sensors. PMID:26937848

  20. Localization of narrowband single photon emitters in nanodiamonds

    CERN Document Server

    Bray, Kerem; Elbadawi, Christopher; Fischer, Martin; Schreck, Matthias; Shimoni, Olga; Lobo, Charlene; Toth, Milos; Aharonovich, Igor

    2016-01-01

    Diamond nanocrystals that host room temperature narrowband single photon emitters are highly sought after for applications in nanophotonics and bio-imaging. However, current understanding of the origin of these emitters is extremely limited. In this work we demonstrate that the narrowband emitters are point defects localized at extended morphological defects in individual nanodiamonds. In particular, we show that nanocrystals with defects such as twin boundaries and secondary nucleation sites exhibit narrowband emission that is absent from pristine individual nanocrystals grown under the same conditions. Critically, we prove that the narrowband emission lines vanish when extended defects are removed deterministically using highly localized electron beam induced etching. Our results enhance the current understanding of single photon emitters in diamond, and are directly relevant to fabrication of novel quantum optics devices and sensors.

  1. The emittance of space radiator materials measured at elevated temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Mirtich, M.J. [Lewis Research Center, Cleveland, OH (United States); DiFilippo, F. [Case Western Reserve Univ., Cleveland, OH (United States); Barry, J.; Kussmaul, M. [Cleveland State Univ., OH (United States)

    1994-09-01

    The spectral emittances of textured space radiator materials between 1.7 and 14.7 {mu}m have been evaluated at room temperature and elevated temperature (630{degrees}C) in air. Heating in air caused a permanent increase in spectral emittance for all materials tested: HCl/ion beam textured 304 stainless steel, untextured Ti (6 percent Al, 4 percent V), and sandblasted Ti (6 percent Al, 4 percent V). Changes in the surface chemistry and/or surface morphology of these materials were also observed. Elevated temperature spectral emittance was measured in an argon atmosphere and compared to the measurements in air. Similarity between the room temperature and elevated temperature spectral emittance measurements was also investigated, and limited agreement was found.

  2. Simulation of emittance growth in the ALS [Advanced Light Source] pre-injector

    International Nuclear Information System (INIS)

    Transverse and longitudinal beam dynamics in the ALS preinjector were simulated with a 2 1/2 D code. Strong space charge-forces at low energy and nonlinearities caused emittances to grow. However, careful tuning of the bunching system and the linac reduced emittance growth to an acceptable label. About 1/3 of the gun output are within the required energy spread and the normalized rms emittance is significantly lower than the expected value. 3 refs., 7 figs., 1 tab

  3. Monolithic multinozzle emitters for nanoelectrospray mass spectrometry

    Science.gov (United States)

    Wang, Daojing; Yang, Peidong; Kim, Woong; Fan, Rong

    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.

  4. Longitudinal emittance control in high intensity proton synchrotrons

    International Nuclear Information System (INIS)

    Experiments of synchrotron injection using the direct fast chopped H- beam extracted from a surface-plasma-type H- ion source has been successfully achieved. The injection phase of the fast chopped beam from linac into the booster synchrotron is adjustable to the center of rf bucket by using this beam. It was obtained that the longitudinal emittance was controlled at the extraction of the booster synchrotron, and that the beam loss during the injection into main ring of the KEK-PS was reduced by this fast chopped beam. (author)

  5. 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

  6. Space charge dominated beam transport

    International Nuclear Information System (INIS)

    We consider beam transport systems where space charge forces are comparable in strength with the external focusing force. Space charge then plays an important role for beam transmission and emittance growth. We use the envelope model for matching and the generalized field energy equations to study emittance growth. Analytic results are compared with numerical simulation. (orig.)

  7. Development of real-time emittance monitor using pepper-pot method

    International Nuclear Information System (INIS)

    At Osaka University RCNP cyclotron facility, researches aimed at high-intensity and high quality of the proton beam have been carried out. In the current beam acceleration, there is one problem that the beam generated by the ion source is not injected to the AVF cyclotron downstream efficiently. This is due to the mismatch of acceptance of the AVF and the emittance of the ion source beam. Therefore, in order to realize the beam injection more efficient, it is necessary to measure and evaluate emittance and phase space distributions of the beam rapidly. In our facility, emittance measurements using a slit and a rotating profile monitor have been performed. Thus, the measurement time shortened from 30 minutes to 75 seconds. Thus, it becomes possible to adjust the parameters of the beam transport system and the ion source while the measure emittance, however, in order to improve the control of the beam further, we're aiming the development of real-time emittance measurement system using pepper-pot method. Since we moved a slit in the conventional emittance measurement system mechanically, it took a measurement time of 1 minute because it becomes rate-determining. On the other hand, since there is no mechanical drive in repeated measurements by using a MCP and pepper-pot mask drilled uniformly in pepper-pot method, significant shortening of measurement time is expected than the measurement time using a slit current. (author)

  8. Is transverse feedback necessary for the SSC emittance preservation? (Vibration noise analysis and feedback parameters optimization)

    International Nuclear Information System (INIS)

    The paper considers the Superconducting Super Collider (SSC) site ground motion measurements as well as data from accelerators worldwide about noises that worsen beam performance. Unacceptably fast emittance growth due to these noises is predicted for the SSC. A transverse feedback system was found to be the only satisfactory alternative to prevent emittance decay. Optimization of the primary feedback parameters was done

  9. 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.

  10. High brightness fiber laser pump sources based on single emitters and multiple single emitters

    Science.gov (United States)

    Scheller, Torsten; Wagner, Lars; Wolf, Jürgen; Bonati, Guido; Dörfel, Falk; Gabler, Thomas

    2008-02-01

    Driven by the potential of the fiber laser market, the development of high brightness pump sources has been pushed during the last years. The main approaches to reach the targets of this market had been the direct coupling of single emitters (SE) on the one hand and the beam shaping of bars and stacks on the other hand, which often causes higher cost per watt. Meanwhile the power of single emitters with 100μm emitter size for direct coupling increased dramatically, which also pushed a new generation of wide stripe emitters or multi emitters (ME) of up to 1000μm emitter size respectively "minibars" with apertures of 3 to 5mm. The advantage of this emitter type compared to traditional bars is it's scalability to power levels of 40W to 60W combined with a small aperture which gives advantages when coupling into a fiber. We show concepts using this multiple single emitters for fiber coupled systems of 25W up to 40W out of a 100μm fiber NA 0.22 with a reasonable optical efficiency. Taking into account a further efficiency optimization and an increase in power of these devices in the near future, the EUR/W ratio pushed by the fiber laser manufacturer will further decrease. Results will be shown as well for higher power pump sources. Additional state of the art tapered fiber bundles for photonic crystal fibers are used to combine 7 (19) pump sources to output powers of 100W (370W) out of a 130μm (250μm) fiber NA 0.6 with nominal 20W per port. Improving those TFB's in the near future and utilizing 40W per pump leg, an output power of even 750W out of 250μm fiber NA 0.6 will be possible. Combined Counter- and Co-Propagated pumping of the fiber will then lead to the first 1kW fiber laser oscillator.

  11. Summary report on transverse emittance preservation

    International Nuclear Information System (INIS)

    During the past years, significant progress has been made in understanding the beam transverse emittance blow-up and its preservation. However, one often finds him-/herself ignorant when he/she tries to explain what was observed in an existing machine or to predict what will happen in a machine under design. There are a number of such examples given in this report. Some of them are even fundamental. These are the challenges. But they are also the directions leading to new achievements. The workshop gladly acknowledged them and promised to work on them

  12. Emittance growth in rf linacs

    International Nuclear Information System (INIS)

    As the space-charge limit is approached, the current that can be accelerated in an rf linac and the output emittance that can be expected are discussed. The role of the envelope equations to estimate limits is outlined. The results of numerical experiments to explore general properties of emittance growth are given

  13. Developments of fast emittance monitors for ion sources at RCNP

    Energy Technology Data Exchange (ETDEWEB)

    Yorita, T., E-mail: yorita@rcnp.osaka-u.ac.jp; Hatanaka, K.; Fukuda, M.; Shimada, K.; Yasuda, Y.; Saito, T.; Tamura, H.; Kamakura, K. [Research Center for Nuclear Physics (RCNP), Osaka University, Osaka 567-0047 (Japan)

    2016-02-15

    Recently, several developments of low energy beam transport line and its beam diagnostic systems have been performed to improve the injection efficiency of ion beam to azimuthally varying field cyclotron at Research Center for Nuclear Physics, Osaka University. One of those is the fast emittance monitor which can measure within several seconds for the efficient beam development and a Pepper-Pot Emittance Monitor (PPEM) has been developed. The PPEM consists of pepper-pot mask, multichannel plate, fluorescent screen, mirror, and CCD camera. The CCD image is taken via IEEE1394b to a personal computer and analyzed immediately and frequently, and then real time measurement with about 2 Hz has been achieved.

  14. Developments of fast emittance monitors for ion sources at RCNP

    International Nuclear Information System (INIS)

    Recently, several developments of low energy beam transport line and its beam diagnostic systems have been performed to improve the injection efficiency of ion beam to azimuthally varying field cyclotron at Research Center for Nuclear Physics, Osaka University. One of those is the fast emittance monitor which can measure within several seconds for the efficient beam development and a Pepper-Pot Emittance Monitor (PPEM) has been developed. The PPEM consists of pepper-pot mask, multichannel plate, fluorescent screen, mirror, and CCD camera. The CCD image is taken via IEEE1394b to a personal computer and analyzed immediately and frequently, and then real time measurement with about 2 Hz has been achieved

  15. Emittance control and RF bunch compression in the NSRRC photoinjector

    Science.gov (United States)

    Lau, W. K.; Hung, S. B.; Lee, A. P.; Chou, C. S.; Huang, N. Y.

    2011-05-01

    The high-brightness photoinjector being constructed at the National Synchrotron Radiation Research Center is for testing new accelerator and light-source concepts. It is the so-called split photoinjector configuration in which a short solenoid magnet is used for emittance compensation. The UV-drive laser pulses are also shaped to produce uniform cylindrical bunches for further reduction of beam emittance. However, limited by the available power from our microwave power system, the nominal accelerating gradient in the S-band booster linac is set at 18 MV/m. A simulation study with PARMELA shows that the linac operating at this gradient fails to freeze the electron beam emittance at low value. A background solenoid magnetic field is applied for beam emittance control in the linac during acceleration. A satisfactory result that meets our preliminary goal has been achieved with the solenoid magnetic field strength at 0.1 T. RF bunch compression as a means to achieve the required beam brightness for high-gain free-electron laser experiments is also examined. The reduction of bunch length to a few hundred femtoseconds can be obtained.

  16. Emittance control and RF bunch compression in the NSRRC photoinjector

    International Nuclear Information System (INIS)

    The high-brightness photoinjector being constructed at the National Synchrotron Radiation Research Center is for testing new accelerator and light-source concepts. It is the so-called split photoinjector configuration in which a short solenoid magnet is used for emittance compensation. The UV-drive laser pulses are also shaped to produce uniform cylindrical bunches for further reduction of beam emittance. However, limited by the available power from our microwave power system, the nominal accelerating gradient in the S-band booster linac is set at 18 MV/m. A simulation study with PARMELA shows that the linac operating at this gradient fails to freeze the electron beam emittance at low value. A background solenoid magnetic field is applied for beam emittance control in the linac during acceleration. A satisfactory result that meets our preliminary goal has been achieved with the solenoid magnetic field strength at 0.1 T. RF bunch compression as a means to achieve the required beam brightness for high-gain free-electron laser experiments is also examined. The reduction of bunch length to a few hundred femtoseconds can be obtained.

  17. Development of C-band deflector for slice emittance monitoring of new electron gun

    International Nuclear Information System (INIS)

    The advanced RF electron gun was installed for an electronic source of a high charge and a low emittance in KEK e+/e- Linac, and the sliced bunch monitor is needed to achieve the required emittance for the SuperKEKB injection. In the KEK-Linac, we are monitoring using a fluorescent plate on the beam line. It is possible to measure the projection emittance of the beam in this way, however it is not possible to measure the slice emittance. To develop an electron gun which can be generating a beam of super-low emittance corresponding to SuperKEKB, monitoring of the slice emittance is required. The slice of time direction on a beam can be acquired by measuring the beam sliced with the RF-deflector using a fluorescent plate. RF-deflector performance is square root of RF frequency, has developed a high-powered ones corresponding to 10 GeV beam using X-band frequency at near the end of KEK-Linac. However, because the beam energy is about 10 MeV at the RF gun exit, enough resolution is obtained even by low energy. So, we have developed a new low energy RF-deflector using C-band frequency. (author)

  18. Beam-beam studies for the High-Energy LHC

    CERN Document Server

    Ohmi, K; Zimmermann, F

    2011-01-01

    LHC upgrades are being considered both towards higher luminosity (HL-LHC) and towards higher energy (HE-LHC). In this paper we report initial studies of the beam-beam effects in the HE-LHC [1]. The HE-LHC aims at beam energies of 16.5 TeV, where the transverse emittance decreases due to synchrotron radiation with a 2-hour damping time. As a result of this emittance, shrinkage the beam-beam parameter increases with time, during a physics store. The beam-beam limit in the HE-LHC is explored using computer simulations.

  19. Real-time modeling of transverse emittance growth due to ground motion

    International Nuclear Information System (INIS)

    Ground motion noise at frequencies around 1 kHz causes growth of transverse emittance of the Superconducting Super Collider (SSC) collider beams. The effect was quantitatively investigated using real-time signals from seismometers installed at the tunnel depth and on the surface. The SSC beam was modeled as an ensemble of oscillators with a spread of betatron frequencies. The effect of transverse feedback on emittance growth was investigated

  20. Emittance Studies of the BNL/SLAC/UCLA 1.6 Cell Photocathode RF Gun

    Energy Technology Data Exchange (ETDEWEB)

    Palmer, D.T.; /SLAC; Wang, X.J.; /Brookhaven; Miller, R.H.; /SLAC; Babzien, M.; Ben-Zvi, I.; /Brookhaven; Pellegrini, C.; /UCLA; Sheehan, J.; Skaritka, J.; /Brookhaven; Winick, H.; /SLAC; Woodle, M.; Yakimenko, V.; /Brookhaven

    2011-09-09

    The symmetrized 1.6 cell S-band photocathode gun developed by the BNL/SLAC/UCLA collaboration is in operation at the Brookhaven Accelerator Test Facility (ATF). A novel emittance compensation solenoid magnet has also been designed, built and is in operation at the ATF. These two subsystems form an emittance compensated photoinjector used for beam dynamics, advanced acceleration and free electron laser experiments at the ATF. The highest acceleration field achieved on the copper cathode is 150 MV/m, and the guns normal operating field is 130 MV/m. The maximum rf pulse length is 3 {mu}s. The transverse emittance of the photoelectron beam were measured for various injection parameters. The 1 nC emittance results are presented along with electron bunch length measurements that indicated that at above the 400 pC, space charge bunch lengthening is occurring. The thermal emittance, {epsilon}{sub o}, of the copper cathode has been measured.

  1. Muon Emittance Exchange with a Potato Slicer

    Energy Technology Data Exchange (ETDEWEB)

    Summers, D. J. [Univ. of Mississippi, Oxford, MS (United States); Hart, T. L. [Univ. of Mississippi, Oxford, MS (United States); Acosta, J. G. [Univ. of Mississippi, Oxford, MS (United States); Cremaldi, L. M. [Univ. of Mississippi, Oxford, MS (United States); Oliveros, S. J. [Univ. of Mississippi, Oxford, MS (United States); Perera, L. P. [Univ. of Mississippi, Oxford, MS (United States); Neuffer, D. V. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)

    2015-04-15

    We propose a novel scheme for final muon ionization cooling with quadrupole doublets followed by emittance exchange in vacuum to achieve the small beam sizes needed by a muon collider. A flat muon beam with a series of quadrupole doublet half cells appears to provide the strong focusing required for final cooling. Each quadrupole doublet has a low beta region occupied by a dense, low Z absorber. After final cooling, normalized transverse, longitudinal, and angular momentum emittances of 0.100, 2.5, and 0.200 mm-rad are exchanged into 0.025, 70, and 0.0 mm-rad. A skew quadrupole triplet transforms a round muon bunch with modest angular momentum into a flat bunch with no angular momentum. Thin electrostatic septa efficiently slice the flat bunch into 17 parts. The 17 bunches are interleaved into a 3.7 meter long train with RF deflector cavities. Snap bunch coalescence combines the muon bunch train longitudinally in a 21 GeV ring in 55 µs, one quarter of a synchrotron oscillation period. A linear long wavelength RF bucket gives each bunch a different energy causing the bunches to drift in the ring until they merge into one bunch and can be captured in a short wavelength RF bucket with a 13% muon decay loss and a packing fraction as high as 87 %.

  2. Muon Emittance Exchange with a Potato Slicer

    CERN Document Server

    Summers, D J; Acosta, J G; Cremaldi, L M; Oliveros, S J; Perera, L P; Neuffer, D V

    2015-01-01

    We propose a novel scheme for final muon ionization cooling with quadrupole doublets followed by emittance exchange in vacuum to achieve the small beam sizes needed by a muon collider. A flat muon beam with a series of quadrupole doublet half cells appears to provide the strong focusing required for final cooling. Each quadrupole doublet has a low beta region occupied by a dense, low Z absorber. After final cooling, normalized transverse, longitudinal, and angular momentum emittances of 0.100, 2.5, and 0.200 mm-rad are exchanged into 0.025, 70, and 0.0 mm-rad. A skew quadrupole triplet transforms a round muon bunch with modest angular momentum into a flat bunch with no angular momentum. Thin electrostatic septa efficiently slice the flat bunch into 17 parts. The 17 bunches are interleaved into a 3.7 meter long train with RF deflector cavities. Snap bunch coalescence combines the muon bunch train longitudinally in a 21 GeV ring in 55 microseconds, one quarter of a synchrotron oscillation period. A linear long ...

  3. Emittance Measurements from a Laser Driven Electron Injector

    International Nuclear Information System (INIS)

    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 π 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 ∼ 13 π 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 π mm-mrad

  4. Ultra-low emittance X-band photocathode RF gun

    Institute of Scientific and Technical Information of China (English)

    TANG Chuan-Xiang; LIU Xiao-Han

    2009-01-01

    In this paper,we present the simulation results of a 1.6 cell X-band photocathode RF gun for ultra-low emittance electron beams.It will work at 9.3 GHz.The emittance,bunch length,electron energy and energy spread at the gun exit are optimized at bunch charge of 1pC using PARMELA.Electron bunches type coupler is adopted in this gun and an initial simulation by MAFIA is also given in this paper.

  5. Studies of emittance of multiply charged ions extracted from high temperature superconducting electron cyclotron resonance ion source, PKDELIS

    International Nuclear Information System (INIS)

    For the high current injector project at Inter University Accelerator Centre, a high temperature superconducting electron cyclotron resonance (ECR) ion source, PKDELIS, would provide the high charge state ions. The emittance of the ECR ion source is an important parameter to design further beam transport system and to match the acceptances of the downstream radio frequency quadrupole and drift tube linac accelerators of the high current injector. The emittance of the analyzed beam of PKDELIS ECR source has been measured utilizing the three beam size technique. A slit and two beam profile monitors positioned at fixed distances from each other were used to measure the beam size. The digitized beam profiles have been analyzed to determine the emittance of various multiply charged ions. The variation of emittance with gas mixing, ultrahigh frequency power, and extraction energy are discussed in this presentation.

  6. IMPACT simulation and the SNS linac beam

    International Nuclear Information System (INIS)

    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

  7. Electron Cloud at Low Emittance in CesrTA

    International Nuclear Information System (INIS)

    The Cornell Electron Storage Ring (CESR) has been reconfigured as a test accelerator (CesrTA) for a program of electron cloud (EC) research at ultra low emittance. The instrumentation in the ring has been upgraded with local diagnostics for measurement of cloud density and with improved beam diagnostics for the characterization of both the low emittance performance and the beam dynamics of high intensity bunch trains interacting with the cloud. A range of EC mitigation methods have been deployed and tested and their effectiveness is discussed. Measurements of the electron cloud's effect on the beam under a range of conditions are discussed along with the simulations being used to quantitatively understand these results.

  8. Extraction induced emittance growth for negative ion sources

    International Nuclear Information System (INIS)

    Nonlinear emittance growth produced by ion extraction is considered by a 3-D analysis in a Vlasov-Poisson-Boltzmann formulation. Phenomena considered include: presheath effects, including electron depletion, electron sheath accumulation (for large transverse magnetic fields), nonlinear sheath fields (obtained by a self-consistent solution with an assumed quasi-equilibrium positive ion distribution and at least one Vlasov distribution), nonlinear fringe fields produced by the accelerator-extractor itself obtained self-consistently with item 3 above, nonlinear space charge of the beam itself, and beam in conjunction with extracted electrons. For specific volume negative ion source configurations, an investigation of the contribution of aberrations caused by an electron trap and electron accumulation in the extraction sheath are studied. Either of these effects can contribute significantly to the beam emittance, possibly dominating the contribution of the negative ion temperature in the source. 2 refs., 10 figs

  9. Electron Cloud at Low Emittance in CesrTA

    Energy Technology Data Exchange (ETDEWEB)

    Palmer, Mark; /Cornell U., CLASSE; Alexander, James; /Cornell U., CLASSE; Billing, Michael; /Cornell U., CLASSE; Calvey, Joseph; /Cornell U., CLASSE; Conolly, Christopher; /Cornell U., CLASSE; Crittenden, James; /Cornell U., CLASSE; Dobbins, John; /Cornell U., CLASSE; Dugan, Gerald; /Cornell U., CLASSE; Eggert, Nicholas; /Cornell U., CLASSE; Fontes, Ernest; /Cornell U., CLASSE; Forster, Michael; /Cornell U., CLASSE; Gallagher, Richard; /Cornell U., CLASSE; Gray, Steven; /Cornell U., CLASSE; Greenwald, Shlomo; /Cornell U., CLASSE; Hartill, Donald; /Cornell U., CLASSE; Hopkins, Walter; /Cornell U., CLASSE; Kreinick, David; /Cornell U., CLASSE; Kreis, Benjamin; /Cornell U., CLASSE; Leong, Zhidong; /Cornell U., CLASSE; Li, Yulin; /Cornell U., CLASSE; Liu, Xianghong; /Cornell U., CLASSE /Cornell U., CLASSE /Cornell U., CLASSE /Cornell U., CLASSE /Cornell U., CLASSE /Cornell U., CLASSE /Cornell U., CLASSE /Cornell U., CLASSE /Cornell U., CLASSE /Cornell U., CLASSE /Cornell U., CLASSE /Cornell U., CLASSE /Cornell U., CLASSE /Cornell U., CLASSE /Cornell U., CLASSE /Cornell U., CLASSE /Cornell U., CLASSE /Cornell U., CLASSE /Cornell U., CLASSE /Cornell U., CLASSE /Cornell U., CLASSE /Cornell U., CLASSE /Cornell U., CLASSE /Cornell U., CLASSE /Cornell U., CLASSE /Cornell U., CLASSE /CERN /CERN /CERN /CERN /CERN /CERN; /more authors..

    2012-07-06

    The Cornell Electron Storage Ring (CESR) has been reconfigured as a test accelerator (CesrTA) for a program of electron cloud (EC) research at ultra low emittance. The instrumentation in the ring has been upgraded with local diagnostics for measurement of cloud density and with improved beam diagnostics for the characterization of both the low emittance performance and the beam dynamics of high intensity bunch trains interacting with the cloud. A range of EC mitigation methods have been deployed and tested and their effectiveness is discussed. Measurements of the electron cloud's effect on the beam under a range of conditions are discussed along with the simulations being used to quantitatively understand these results.

  10. Diamondoid monolayers as electron emitters

    Science.gov (United States)

    Yang, Wanli; Fabbri, Jason D.; Melosh, Nicholas A.; Hussain, Zahid; Shen, Zhi-Xun

    2012-04-10

    Provided are electron emitters based upon diamondoid monolayers, preferably self-assembled higher diamondoid monolayers. High intensity electron emission has been demonstrated employing such diamondoid monolayers, particularly when the monolayers are comprised of higher diamondoids. The application of such diamondoid monolayers can alter the band structure of substrates, as well as emit monochromatic electrons, and the high intensity electron emissions can also greatly improve the efficiency of field-effect electron emitters as applied to industrial and commercial applications.

  11. Emittance measurement for high-brightness electron guns

    International Nuclear Information System (INIS)

    An emittance measurement system based on a high-precision pepper-pot technique has been developed for electron guns with low emittance of around πmm-mrad. Electron guns with a 1 mmφ cathode, the material of which is impregnated tungsten or single-crystal lanthanum hexaboride (La1-xCex)B6, have been developed. The performance has been evaluated by putting stress on cathode roughness, which gives rise to an angular divergence, according to the precise emittance measurement system. A new type of cathode holder, which is a modified version of the so called Vogel type, was developed and the beam uniformity has been improved. (Author) 5 figs., tab., 9 refs

  12. Space charge dominated beams

    International Nuclear Information System (INIS)

    After an introductory section on the relationship between emittance and beam Coulomb energy we discuss the properties of space charge dominated beams in progressive steps: from uniformly charged bunched beams to non-uniformly charged beams to correlation effects between particles (simulation beams or 'crystalline' beams). A practical application can be found in the beam dynamics of a high-current injector. The concept of correlation energy is of practical interest in computer simulation of high-brilliance beams, where one deals with an artificially enhanced two-particle Coulomb energy, if many real particles are combined into one simulation super-particle. This can be a source of non-physical emittance growth. (orig./HSI)

  13. Sectional and projectional emittance measurements (abstract)a

    International Nuclear Information System (INIS)

    For many applications of ion sources the quality of the generated ion beam plays an increasingly important role. Ion sources consist of the plasma generator and the extraction system. Both parts can, due to high ion temperature or various aberrations, contribute to a degrading of the beam quality. Though the beam quality is determined by many more factors, the transverse motion of the particles certainly is one of the important parameters. Knowledge of it can be obtained by an emittance measurement. This is best done in a four-dimensional phase space, yielding a density distribution as function of the transverse spatial and momentum coordinates. Often, however, due to practical considerations, only two dimensions of the four-dimensional open-quote open-quote trace space close-quote close-quote are being measured. This two-dimensional data can be obtained as a section or as a projection of the four-dimensional trace space, where both methods have their merits. Projectional emittance measurements can usually be performed much easier and quicker, but by the projection of the four-dimensional space onto a two-dimensional plane information is lost. And although not all the particles of the beam are represented in a section of trace space, here aberrative distortions of the emittance can be seen most clearly and allow an easier comparison to numerically obtained data. The advantages and disadvantages of both methods are discussed. Numerical and experimental examples are presented. copyright 1996 American Institute of Physics

  14. Emittance measurement techniques used in the 1 MeV RFQ for the PET isotope linac at Fermilab

    International Nuclear Information System (INIS)

    Beam emittance measurements have been performed on the 3He+ beam at the PET isotope production accelerator, being commissioned at Fermilab for the Biomedical Research Foundation in Shreveport, Louisiana, USA. Emittances have been measured at injection to and extraction from the first RFQ, at 20 keV and 1 MeV, respectively. A single slit followed by a 48 electrode collector is used in the standard way to measure the divergence of the 3He+ beam as a function of position. Noise reduction operations have been developed, both in hardware and software. These techniques and the emittance measurement results are presented

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

    International Nuclear Information System (INIS)

    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.

  16. Minimizing Emittance for the CLIC Damping Ring

    CERN Document Server

    Braun, H; Levitchev, E; Piminov, P; Schulte, Daniel; Siniatkin, S; Vobly, P P; Zimmermann, Frank; Zolotarev, Konstantin V; CERN. Geneva

    2006-01-01

    The CLIC damping rings aim at unprecedented small normalized equilibrium emittances of 3.3 nm vertical and 550 nm horizontal, for a bunch charge of 2.6·109 particles and an energy of 2.4 GeV. In this parameter regime the dominant emittance growth mechanism is intra-beam scattering. Intense synchrotron radiation damping from wigglers is required to counteract its effect. Here the overall optimization of the wiggler parameters is described, taking into account state-of-the-art wiggler technologies, wiggler effects on dynamic aperture, and problems of wiggler radiation absorption. Two technical solutions, one based on superconducting magnet technology the other on permanent magnets are presented. Although dynamic aperture and tolerances of this ring design remain challenging, benefits are obtained from the strong damping. For optimized wigglers, only bunches for a single machine pulse may need to be stored, making injection/extraction particularly simple and limiting the synchrotron-radiation power. With a 36...

  17. Beam Dynamics for ARIA

    Energy Technology Data Exchange (ETDEWEB)

    Ekdahl, Carl August Jr. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2014-10-14

    Beam dynamics issues are assessed for a new linear induction electron accelerator being designed for flash radiography of large explosively driven hydrodynamic experiments. Special attention is paid to equilibrium beam transport, possible emittance growth, and beam stability. It is concluded that a radiographic quality beam will be produced possible if engineering standards and construction details are equivalent to those on the present radiography accelerators at Los Alamos.

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

    International Nuclear Information System (INIS)

    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 Cs2Te 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. Emittance compensation for an SRF photo injector

    Energy Technology Data Exchange (ETDEWEB)

    Vennekate, H.; Lu, P. [HZDR (Germany); TU Dresden (Germany); Arnold, A.; Mucek, P.; Teichert, J.; Xiang, R. [HZDR (Germany); Kamps, T. [HZB (Germany); Kneisel, P. [JLab (Germany); Voelker, J. [HZB (Germany); Humboldt Universitaet Berlin (Germany); Volkov, V. [BINP (Germany); Will, I. [MBI (Germany)

    2013-07-01

    The development of a superconducting photo injector is an ongoing challenge at the HZDR in Dresden. Several milestones like the first operation of a half cell niobium cavity in 2002 and the worldwide first beam transfer from a 3 1/2-cell SRF gun into an actual accelerator structure have already been accomplished. Nevertheless, as superconducting electron sources are of great interest for future ERL or cw operated FEL projects, studies to improve their output parameters and stability continue to get them on the same level as their normal conducting counterparts. The talk discusses several of the current approaches to reduce the transversal emittance of the next 3 1/2-cell cavity at the HZDR including the installation of a superconducting solenoid within the gun's cryostat.

  1. Matching of horizontal and vertical emittances using a thin scatterer

    International Nuclear Information System (INIS)

    An isocentric superconducting rotating-gantry for heavy-ion therapy is being developed at NIRS. This rotating gantry can transport heavy ions having 430 MeV/u to an isocenter with irradiation angles of over ±180 degrees, and is further capable of performing fast raster-scanning irradiation. In the treatment using the rotating gantry, it is important to obtain a circular beam spot at the isocenter independent of the gantry angle. To accomplish this, we initially determined phase-space distributions of extracted beams from the HIMAC synchrotron ring, and further, matching of horizontal and vertical emittances using a thin scatterer was performed. We report results of the phase-space measurements as well as the emittance matching. (author)

  2. Beam instrumentation performance overview

    CERN Document Server

    Sapinski, M

    2012-01-01

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

  3. Combustion powered thermophotovoltaic emitter system

    Energy Technology Data Exchange (ETDEWEB)

    McHenry, R.S. [Naval Academy, Annapolis, MD (United States). Naval Architecture, Ocean and Marine Engineering

    1995-07-01

    The US Naval Academy (USNA) has recently completed an engineering design project for a high temperature thermophotovoltaic (TPV) photon emitter. The final apparatus was to be portable, completely self contained, and was to incorporate cycle efficiency optimization such as exhaust stream recuperation. Through computer modeling and prototype experimentation, a methane fueled emitter system was designed from structural ceramic materials to fulfill the high temperature requirements necessary for high system efficiency. This paper outlines the engineering design process, discusses obstacles and solutions encountered, and presents the final design.

  4. Emittance Growth at LHC Injection from SPS and LHC Kicker Ripple

    CERN Document Server

    Kotzian, G; Ducimetière, L; Goddard, B; Höfle, Wolfgang

    2008-01-01

    Fast pulsed kicker magnets are used to extract beams from the SPS and inject them into the LHC. The kickers exhibit time-varying structure in the pulse shape which translates into small offsets with respect to the closed orbit at LHC injection. The LHC damper systems will be used to damp out the resulting betatron oscillations, to keep the growth in the transverse emittance within specification. This paper describes the results of the measurements of the kicker ripple for the two systems, both in the laboratory and with beam, and presents the simulated performance of the transverse damper in terms of beam emittance growth. The implications for LHC operation are discussed.

  5. Directional couplers with integrated carbon nanotube incandescent light emitters

    OpenAIRE

    Fechner, Randy G.; Pyatkov, Felix; Khasminskaya, Svetlana; Flavel, Benjamin S.; Krupke, Ralph; Pernice, Wolfram H. P.

    2016-01-01

    We combine on-chip single-walled carbon nanotubes (SWNTs) emitters with directional coupling devices as fundamental building blocks for carbon photonic systems. These devices are essential for studying the emission properties of SWNTs in the few photon regime for future applications in on-chip quantum photonics. The combination of SWNTs with on-chip beam splitters herein provides the basis for correlation measurements as necessary for nanoscale source characterization. The employed fabricatio...

  6. Fine-tuning to minimize emittances of J-PARC RF-driven H- ion source

    Science.gov (United States)

    Ueno, A.; Ohkoshi, K.; Ikegami, K.; Takagi, A.; Asano, H.; Oguri, H.

    2016-02-01

    The Japan Proton Accelerator Research Complex (J-PARC) cesiated RF-driven H- ion source has been successfully operated for about one year. By the world's brightest level beam, the J-PARC design beam power of 1 MW was successfully demonstrated. In order to minimize the transverse emittances, the rod-filter-field (RFF) was optimized by changing the triple-gap-lengths of each of pairing five piece rod-filter-magnets. The larger emittance degradation seems to be caused by impurity-gases than the RFF. The smaller beam-hole-diameter of the extraction electrode caused the more than expected improvements on not only the emittances but also the peak beam intensity.

  7. Fine-tuning to minimize emittances of J-PARC RF-driven H− ion source

    International Nuclear Information System (INIS)

    The Japan Proton Accelerator Research Complex (J-PARC) cesiated RF-driven H− ion source has been successfully operated for about one year. By the world’s brightest level beam, the J-PARC design beam power of 1 MW was successfully demonstrated. In order to minimize the transverse emittances, the rod-filter-field (RFF) was optimized by changing the triple-gap-lengths of each of pairing five piece rod-filter-magnets. The larger emittance degradation seems to be caused by impurity-gases than the RFF. The smaller beam-hole-diameter of the extraction electrode caused the more than expected improvements on not only the emittances but also the peak beam intensity

  8. Numerical simulation of low emittance tuning at SuperKEKB

    International Nuclear Information System (INIS)

    SuperKEKB is a double ring e+e- collider aimed to reach new luminosity frontier. The target peak luminosity is 8x103 cm-2s-1, which is 40 times higher than the world recored achieved by the KEKB machine. The basic strategy to break the KEKB's record is 2 times higher beam current and 20 times smaller beam size at the interaction point. In order to obtain the required beam size, we have to stably storage high quality beams and squeez the beta function. Therefore, one of important accelerator topic in the project is the Low Emittance Tuning (LET) as in high brightness light source projects. We have conducted LET study, shush as error sensitivity, alignment strategy and beam optics correction by using numerical approach. Some remarkable simulation results obtained so far are reported. (author)

  9. Measurement of longitudinal acceptance and emittance of the Oak Ridge Spallation Neutron Source Superconducting Linac

    Science.gov (United States)

    Zhang, Y.; Galambos, J.; Shishlo, A.

    2008-10-01

    The longitudinal acceptance of the Spallation Neutron Source superconducting linac is computed with a longitudinal model. A beam current monitor and beam loss monitors are utilized in a new beam acceptance measurement technique, and the measured results show close agreement with the model. Based on the simulations and on the measurements of the superconducting linac acceptance, we developed a novel method to measure beam bunch shape, beam energy profile, and the longitudinal emittance at the entrance of the linac. The experimental measurements reveal that a large longitudinal beam halo exists in the injected beam to the superconducting linac, and the longitudinal rms emittance is approximately twice that of the nominal design. The simple measurement method is applicable to other superconducting linacs.

  10. Beam position stability in INDUS-2 storage ring

    International Nuclear Information System (INIS)

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

  11. Design of a high duty cycle, asymmetric emittance RF photocathode injector for linear collider applications

    International Nuclear Information System (INIS)

    One of the attractive features of the superconducting approach to linear collider design is that the transverse emittances demanded are much larger than in normal conducting schemes. For TESLA design parameters, the damping rings appear to be relatively large and expensive, and it is therefore of some interest to look into alternative sources. For electrons, a promising source candidate is an rf photocathode. In this paper, the authors present conceptual design work towards development of an asymmetric emittance rf photocathode source which can operate at the TESLA repetition rates and duty cycle, and is capable of emitting beams with the required emittances and charge per pulse

  12. 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.

  13. Time-zero detector based on microchannel plates and a friable dielectric emitter

    International Nuclear Information System (INIS)

    A microchannel plate detector is used in time - zero detectors as a fast multiplier of secondary electrons. For high energy reaction products emitters efficient for fission fragment detection are inadequate because of the very low secondary electron emission coefficient. One way to increase the detection efficiency is to use emitters with control of secondary electron emission by means of friable dielectrics. Such a set up is presented together with experimental tests with a heavy ion beam

  14. Increase of emittance by inverse multiple Touschek effect in a single bunch of charged accelerated particles

    International Nuclear Information System (INIS)

    Coulomb scattering of the longitudinal momentum distribution of particles in an accelerated bunch leads to the creation of a transverse emittance which adds to the natural emittance. This process has been calculated for high energy linacs used in high energy e+e- linear colliders. At beam energies of 500 GeV to 1 TeV, it has been found that the effect is weak

  15. Study of ultra-low emittance design for Spear3 using longitudinal gradient dipole

    Energy Technology Data Exchange (ETDEWEB)

    Wang, M. -H. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Huang, X. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Safranek, J. [SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2015-09-24

    Since its 2003 construction, the SPEAR3 synchrotron light source at SLAC has continuously improved its performance by raising beam current, top-off injection, and smaller emittance. This makes SPEAR3 one of the most productive light sources in the world. Now to further enhance the performance of SPEAR3, we are looking into the possibility of converting SPEAR3 to an ultra-low emittance storage ring within its site constraint.

  16. Low emittance lattice optimization using a multi-objective evolutionary algorithm

    International Nuclear Information System (INIS)

    A low emittance lattice design and optimization procedure are systematically studied with a non-dominated sorting-based multi-objective evolutionary algorithm which not only globally searches the low emittance lattice, but also optimizes some beam quantities such as betatron tunes, momentum compaction factor and dispersion function simultaneously. In this paper the detailed algorithm and lattice design procedure are presented. The Hefei light source upgrade project storage ring lattice, with fixed magnet layout, is designed to illustrate this optimization procedure. (authors)

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

    International Nuclear Information System (INIS)

    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.)

  18. Measurements of Transverse Emittance at the TTF VUV-FEL

    CERN Document Server

    Honkavaara, K

    2005-01-01

    The TESLA Test Facility (TTF) Linac at DESY has been extended to drive a new Free Electron Laser facility VUV-FEL. The 250 m long electron linac has been commissioned in 2004 and in the begin of 2005. Characterization of the electron beam is an essential part of the commissioning. The transverse emittance has been measured at a beam energy of 125 MeV with the four-screen method using optical transition radiation (OTR). We describe the experimental set-up and discuss the data-analysis methods. Experimental results as well as simulations are presented.

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

    International Nuclear Information System (INIS)

    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

  20. Beam-beam effects under the influence of external noise

    OpenAIRE

    Ohmi, K.

    2014-01-01

    Fast external noise, which gives fluctuation into the beam orbit, is discussed in connection with beam-beam effects. Phase noise from crab cavities and detection devices (position monitor) and kicker noise from the bunch by bunch feedback system are the sources. Beam-beam collisions with fast orbit fluctuations with turn by turn or multi-turn correlations, cause emittance growth and luminosity degradation. We discuss the tolerance of the noise amplitude for LHC and HL-LHC.

  1. Resonant-cavity approach to noninvasive, pulse-to-pulse emittance measurement

    International Nuclear Information System (INIS)

    We present a resonant-cavity approach for noninvasive, pulse-to-pulse, beam emittance measurements of noncircular multibunch beams. In a resonant cavity, desired field components can be enhanced up to QLλ/π, where QLλ is the loaded quality factor of the resonant mode λ, when the cavity resonant mode matches the bunch frequency of a bunch-train beam pulse. In particular, a quad cavity, with its quadrupole mode (TM220 for rectangular cavities) at beam operating frequency, rotated 45 deg. with respect to the beamline, extracts the beam quadrupole moment exclusively, utilizing the symmetry of the cavity and some simple networks to suppress common modes. Six successive beam quadrupole-moment measurements, performed at different betatron phases in a linear transport system, determine the beam emittance, i.e., the beam size and shape in the beam's phase space, if the beam current and position at these points are known. In the presence of x-y beam coupling, ten measurements are required. One measurement alone provides the rms beam size of a large aspect ratio beam. The resolution for such a measurement of rms beam size with the rectangular quad-cavity monitor presented in this article is estimated to be on the order of 10 μm. A prototype quad cavity was fabricated and preliminary beam tests were performed at the Next Linear Collider Test Accelerator at the Stanford Linear Accelerator Center. The results were mainly limited by beam jitter and uncertainty in the beam position measurement at the cavity location. This motivated the development of a position-emittance integrated monitor [J. S. Kim et al., Rev. Sci. Instrum. 76, 073302 (2005)

  2. Resonant-cavity approach to noninvasive, pulse-to-pulse emittance measurement

    Science.gov (United States)

    Kim, J. S.; Nantista, C. D.; Miller, R. H.; Weidemann, A. W.

    2005-12-01

    We present a resonant-cavity approach for noninvasive, pulse-to-pulse, beam emittance measurements of noncircular multibunch beams. In a resonant cavity, desired field components can be enhanced up to QLλ/π, where QLλ is the loaded quality factor of the resonant mode λ, when the cavity resonant mode matches the bunch frequency of a bunch-train beam pulse. In particular, a quad cavity, with its quadrupole mode (TM220 for rectangular cavities) at beam operating frequency, rotated 45° with respect to the beamline, extracts the beam quadrupole moment exclusively, utilizing the symmetry of the cavity and some simple networks to suppress common modes. Six successive beam quadrupole-moment measurements, performed at different betatron phases in a linear transport system, determine the beam emittance, i.e., the beam size and shape in the beam's phase space, if the beam current and position at these points are known. In the presence of x-y beam coupling, ten measurements are required. One measurement alone provides the rms beam size of a large aspect ratio beam. The resolution for such a measurement of rms beam size with the rectangular quad-cavity monitor presented in this article is estimated to be on the order of 10μm. A prototype quad cavity was fabricated and preliminary beam tests were performed at the Next Linear Collider Test Accelerator at the Stanford Linear Accelerator Center. The results were mainly limited by beam jitter and uncertainty in the beam position measurement at the cavity location. This motivated the development of a position-emittance integrated monitor [J. S. Kim et al., Rev. Sci. Instrum. 76, 073302 (2005)].

  3. Longitudinal emittance: An introduction to the concept and survey of measurement techniques including design of a wall current monitor

    Science.gov (United States)

    Webber, Robert C.

    1990-10-01

    The properties of charged particle beams associated with the distribution of the particles in energy and in time can be grouped together under the category of longitudinal emittance. This article is intended to provide an intuitive introduction to the concepts of longitudinal emittance; to provide an incomplete survey of methods used to measure this emittance and related properties of bunch length and momentum spread; and to describe the detailed design of a 6 Ghz bandwidth resistive wall current monitor useful for measuring bunch shapes of moderate to high intensity beams. Overall, the article is intended to be broad in scope, in most cases deferring details to cited original papers.

  4. Longitudinal emittance: An introduction to the concept and survey of measurement techniques including design of a wall current monitor

    International Nuclear Information System (INIS)

    The properties of charged particle beams associated with the distribution of the particles in energy and in time can be grouped together under the category of longitudinal emittance. This article is intended to provide an intuitive introduction to the concepts of longitudinal emittance; to provide an incomplete survey of methods used to measure this emittance and related properties of bunch length and momentum spread; and to describe the detailed design of a 6 Ghz bandwidth resistive wall current monitor useful for measuring bunch shapes of moderate to high intensity beams. Overall, the article is intended to be broad in scope, in most cases deferring details to cited original papers

  5. Longitudinal emittance: An introduction to the concept and survey of measurement techniques including design of a wall current monitor

    International Nuclear Information System (INIS)

    The properties of charged particle beams associated with the distribution of the particles in energy and in time can be grouped together under the category of longitudinal emittance. This article is intended to provide an intuitive introduction to the concepts longitudinal emittance; to provide an incomplete survey of methods used to measure this emittance and the related properties of bunch length and momentum spread; and to describe the detailed design of a 6 Ghz bandwidth resistive wall current monitor useful for measuring bunch shapes of moderate to high intensity beams. Overall, the article is intended to be broad in scope, in most cases deferring details to cited original papers. 37 refs., 21 figs

  6. Comparison between 50 W tapered laser arrays and tapered single emitters

    Science.gov (United States)

    Scholz, Christian; Boucke, Konstantin; Poprawe, Reinhart; Keleman, Marc T.; Weber, Jürgen; Mikulla, Michael; Weimann, Günter

    2006-02-01

    During the last few years high power diode laser arrays have become well established for direct material processing due to their high efficiency of more than 50%. But standard broad-area waveguide designs are susceptible to modal instabilities and filamentations resulting in low beam qualities. The beam quality increases by more than a factor of four by using tapered laser arrays, but so far they suffer from lower efficiencies. Therefore tapered lasers are mainly used today as single emitters in external resonator configurations. With increased output power and lifetime, they will be much more attractive for material processing and for pumping of fiber amplifiers. High efficiency tapered mini bars emitting at a wavelength of 980 nm are developed, and in order to qualify the bars, the characteristics of single emitters and mini bars from the same wafer have been compared. The mini bars have a width of 6 mm with 12 emitters. The ridge waveguide tapered lasers consist of a 500 μm long ridge and a 2000 μm long tapered section. The results show very similar behavior of the electro-optical characteristics and the beam quality for single emitters and bars. Due to different junction temperatures, different slope efficiencies were measured: 0.8 W/A for passively cooled mini bars and 1.0 W/A for actively cooled mini-bars and single emitters. The threshold current of 0.7 A per emitter is the same for single emitters and emitter arrays. Output powers of more than 50 W in continuous wave mode for a mini bar with standard packaging demonstrates the increased power of tapered laser bars.

  7. Laser Assisted Emittance Exchange: Downsizing the X-ray Free Electron Laser

    International Nuclear Information System (INIS)

    A technique is proposed to generate electron beam with ultralow transverse emittance through laser assisted transverse-to-longitudinal emittance exchange. In the scheme a laser operating in the TEM10 mode is used to interact with the electron beam in a dispersive region and to initiate the emittance exchange. It is shown that with the proposed technique one can significantly downsize an x-ray free electron laser (FEL), which may greatly extend the availability of these light sources. A hard x-ray FEL operating at 1.5 (angstrom) with a saturation length within 30 meters using a 3.8 GeV electron beam is shown to be practically feasible.

  8. FERMI@Elettra beam-based alignment simulations

    CERN Document Server

    Janeiro Costa, Raul Antonio; CERN. Geneva. BE Department

    2015-01-01

    In this report we present various simulations of the FERMI@Elettra linear accelerator performance with ideal and non-ideal element alignment, showing that a non-ideal machine’s emittance may be over 15 times its ideal counterpart. We then apply beam-based alignment techniques in order to correct this emittance growth, concluding that, under these conditions, dispersion-free steering is enough to reduce the emittance to within 30% of the beam’s original emittance.

  9. Beta emitters and radiation protection

    DEFF Research Database (Denmark)

    Jødal, Lars

    2009-01-01

    , and 90Y, using data from a freely available database. Bremsstrahlung yields were calculated for 90Y shielded by lead, aluminium, or perspex. Bremsstrahlung spectrum from 90Y shielded by perspex was measured, and attenuation of spectrum by lead was calculated. Whole-body and finger doses to persons...... the outside of the primary shielding material. If suitable shielding is used and larger numbers of handlings are divided among several persons, then handling of beta emitters can be a safe procedure....

  10. Description of laser transport and delivery system for the FETS laserwire emittance scanner

    CERN Document Server

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

    2013-01-01

    A beam emittance monitor for H- beams based on laserinduced ions neutralization is being developed at the Front End Test Stand (FETS) at the Rutherford Appleton Laboratory (RAL). In this paper we present a full account of the laser system that will be used for the photodetachment experiment, the optical transport system and the final delivery assembly. All the relevant measurements such as power, spatial and temporal characteristics of the laser, fiber coupling efficiency and final delivery laser beam parameters will be reported.

  11. Experimental studies of emittance growth and energy spread in a photocathode RF gun

    CERN Document Server

    Yang, J; Okada, Y; Yorozu, M; Yanagida, T; Endo, A

    2002-01-01

    In this paper we report on a low emittance electron source, based on a photocathode RF gun, a solenoid magnet and a subsequent linac. The dependencies of the beam transverse emittance and relative energy spread with respect to the laser injection phase of the radio-frequency (RF) gun, the RF phase of the linac and the bunch charge were investigated experimentally. It was found that a lower beam emittance is observed when the laser injection phase in the RF gun is low. The emittance increases almost linearly with the bunch charge under a constant solenoid magnetic field. The corrected relative energy spread of the beam is not strongly dependent on the bunch charge. Finally, an optimal normalized rms transverse emittance of 1.91+-0.28 pi mm mrad at a bunch charge of 0.6 nC was obtained when the RF gun was driven by a picosecond Nd:YAG laser. A corrected relative rms energy spread of 0.2-0.25% at a bunch charge of 0.3-2 nC was obtained after the beam was accelerated to 14 MeV by the subsequent linac.

  12. Experimental studies of emittance growth and energy spread in a photocathode RF gun

    International Nuclear Information System (INIS)

    In this paper we report on a low emittance electron source, based on a photocathode RF gun, a solenoid magnet and a subsequent linac. The dependencies of the beam transverse emittance and relative energy spread with respect to the laser injection phase of the radio-frequency (RF) gun, the RF phase of the linac and the bunch charge were investigated experimentally. It was found that a lower beam emittance is observed when the laser injection phase in the RF gun is low. The emittance increases almost linearly with the bunch charge under a constant solenoid magnetic field. The corrected relative energy spread of the beam is not strongly dependent on the bunch charge. Finally, an optimal normalized rms transverse emittance of 1.91±0.28 πmm mrad at a bunch charge of 0.6 nC was obtained when the RF gun was driven by a picosecond Nd:YAG laser. A corrected relative rms energy spread of 0.2-0.25% at a bunch charge of 0.3-2 nC was obtained after the beam was accelerated to 14 MeV by the subsequent linac

  13. Normal spectral emittance of Inconel 718 aeronautical alloy coated with yttria stabilized zirconia films

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez-Fernandez, L. [Departamento de Fisica de la Materia Condensada, Facultad de Ciencia y Tecnologia, Universidad del Pais Vasco, Barrio Sarriena s/n, 48940 Leioa, Bizkaia (Spain); Industria de Turbo Propulsores, S.A., Planta de Zamudio, Edificio 300, 48170 Zamudio, Bizkaia (Spain); Campo, L. del [Departamento de Fisica de la Materia Condensada, Facultad de Ciencia y Tecnologia, Universidad del Pais Vasco, Barrio Sarriena s/n, 48940 Leioa, Bizkaia (Spain); Perez-Saez, R.B., E-mail: raul.perez@ehu.es [Departamento de Fisica de la Materia Condensada, Facultad de Ciencia y Tecnologia, Universidad del Pais Vasco, Barrio Sarriena s/n, 48940 Leioa, Bizkaia (Spain); Tello, M.J. [Departamento de Fisica de la Materia Condensada, Facultad de Ciencia y Tecnologia, Universidad del Pais Vasco, Barrio Sarriena s/n, 48940 Leioa, Bizkaia (Spain)

    2012-02-05

    Highlights: Black-Right-Pointing-Pointer Emittance of Inconel 718 coated with plasma sprayed yttria stabilized zirconia. Black-Right-Pointing-Pointer The coating is opaque for {lambda} > 9 {mu}m and semi-transparent for {lambda} < 9 {mu}m. Black-Right-Pointing-Pointer In the semi-transparent region the emittance decreases with coating thickness. Black-Right-Pointing-Pointer 300 {mu}m thick coatings are still semi-transparent. Black-Right-Pointing-Pointer In the opaque region the surface roughness determines the emittance level. - Abstract: Knowledge of the radiative behaviour of the yttria stabilized zirconia (YSZ) thermal barrier coatings (TBCs) is needed to perform radiative heat transfer calculations in industrial applications. In this paper, normal spectral emittance experimental data of atmospheric plasma sprayed (PS) YSZ films layered on Inconel 718 substrates are shown. The spectral emittance was measured between 2.5 and 22 {mu}m on samples with film thicknesses ranging from 20 to 280 {mu}m. The samples were heated in a controlled environment, and the emittance was measured for several temperatures between 330 and 730 Degree-Sign C. The dependence of the spectral emittance with film thickness, surface roughness and temperature has been studied and compared with the available results for YSZ TBCs obtained by electron-beam physical vapour deposition. The PS-TBC samples show a Christiansen point at {lambda} = 12.8 {mu}m. The films are semi-transparent for {lambda} < 9 {mu}m, and opaque for {lambda} > 9 {mu}m. In the semi-transparent region, the contribution of the radiation emitted by the Inconel 718 substrate to the global emittance of the samples is analysed. In addition, the influence of the roughness in the emittance values in the opaque spectral region is discussed. Finally, the total normal emittance is obtained as a function of the TBC thickness.

  14. Alpha particle emitters in medicine

    International Nuclear Information System (INIS)

    Radiation-induced cancer of bone, liver and lung has been a prominent harmful side-effect of medical applications of alpha emitters. In recent years, however, the potential use of antibodies labeled with alpha emitting radionuclides against cancer has seemed promising because alpha particles are highly effective in cell killing. High dose rates at high LET, effectiveness under hypoxic conditions, and minimal expectancy of repair are additional advantages of alpha emitters over antibodies labeled with beta emitting radionuclides for cancer therapy. Cyclotron-produced astatine-211 (211At) and natural bismuth-212 (212Bi) have been proposed and are under extensive study in the United States and Europe. Radium-223 (223Ra) also has favorable properties as a potential alpha emitting label, including a short-lived daughter chain with four alpha emissions. The radiation dosimetry of internal alpha emitters is complex due to nonuniformly distributed sources, short particle tracks, and high relative specific ionization. The variations in dose at the cellular level may be extreme. Alpha-particle radiation dosimetry, therefore, must involve analysis of statistical energy deposition probabilities for cellular level targets. It must also account fully for nonuniform distributions of sources in tissues, source-target geometries, and particle-track physics. 18 refs., 4 figs

  15. Simple formulae for the optimization of the FEL gain length including the effects of emittance, betatron oscillations and energy spread

    International Nuclear Information System (INIS)

    Simple analytical formulae are presented for a quick optimization of the Free Electron Laser (FEL) gain length for given values of radiation wavelength, electron beam current, normalized transverse emittance and energy spread. The optimization parameters include the gap size of the wiggler, the wiggler period and the betatron wavelength (in the case of external focusing). The method is based on the handy formulae for the FEL gain of a Gaussian beam including the effects of energy spread, emittance, and betatron oscillations of the electron beam. We have found a simple relation between the minimum FEL gain length and the optimum betatron wavelength for given energy spread, emittance, and gap size of the wiggler. When the emittance is about the radiation wavelength divided by 4ρ and the energy spread is negligible, this relation shows that the gain length is optimized if the betatron wavelength is chosen so that the betatron phase advances by a half radian in the gain length

  16. 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 ...

  17. Emittance dilution through coherent energy spread generation in bending systems

    International Nuclear Information System (INIS)

    For a bunched beam, coherent energy spread generated within a bending system may couple to the transverse (bending) plane coordinates through the chromatic transfer functions of the particular beamline - even an achromatic beamline. The resulting transverse emittance dilution is dependent on the magnitude of the energy spread, its generation rate along the beamline, and the beamline's chromatic transfer functions. The coherent energy spread may be due to resistive-wall wakefields or coherent synchrotron radiation. For specific beamlines, such as a periodic arc or wiggler, the longitudinal-to-transverse coupling is minimal and, in ideal cases, completely suppressed resulting in reduction or cancellation of all transverse emittance dilution effects. This is of particular interest for micro-bunch transport or compression systems such as exist in future FEL or linear collider projects

  18. First observation of the exchange of transverse and longitudinal emittances

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-02-01

    An experimental program to demonstrate a novel phase space manipulation in which the horizontal and longitudinal emittances of a particle beam are exchanged has been completed at the Fermilab A0 Photoinjector. A new beamline, consisting of a TM{sub 110} deflecting mode cavity flanked by two horizontally dispersive doglegs has been installed. We report on the first direct observation of transverse and longitudinal emittance exchange: {l_brace}{var_epsilon}{sub x}{sup n}, {var_epsilon}{sub y}{sup n}, {var_epsilon}{sub z}{sup n}{r_brace} = {l_brace} 2.9 {+-} 0.1, 2.4 {+-} 0.1, 13.1 {+-} 1.3{r_brace} {yields} {l_brace}11.3 {+-} 1.1, 2.9 {+-} 0.5, 3.1 {+-} 0.3{r_brace} mm-mrad.

  19. Computer simulation of the emittance growth due to noise in large hadron colliders

    International Nuclear Information System (INIS)

    The problem of emittance growth due to random fluctuations of the magnetic field in a hadron collider is considered. The results of computer simulations are compared with the analytical theory developed earlier. A good agreement was found between the analytical theory predictions and the computer simulations for the collider tunes located far enough from high order betatron resonances. The dependencies of the emittance growth rate on noise spectral density, beam separation at the Interaction Point (IP) and value of beam separation at long range collisions are studied. The results are applicable to the Superconducting Super Collider (SSC)

  20. Estimation of emittance degradation due to multi-pole fields of XFEL bunch compressors

    International Nuclear Information System (INIS)

    In order to obtain a high-brightness electron beam in an XFEL, the electron bunch should be longitudinally compressed in a linear accelerator using magnetic bunch compressors composed of four bending magnets. The bunch compression requires a large energy chirp on the electron bunch, which produces a horizontal spread of the beam size inside bunch compressors. Since the bending magnets have multi-pole field components, they leak energy-dispersion and degrade emittance downstream of the chicane. In this paper, the emittance degradation due to the multi-pole fields of the bending magnets is estimated using simplified analytical formulae for the XFEL/SPring-8. (author)

  1. Flexible control of femtosecond pulse duration and separation using an emittance-spoiling foil in x-ray free-electron lasers

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Y. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Behrens, C. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Coffee, R. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Decker, F. -J. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Emma, P. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Field, C. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Helml, W. [Technische Univ. Munchen, Garching (Germany); Huang, Z. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Krejcik, P. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Krzywinski, J. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Loos, H. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Lutman, A. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Marinelli, A. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Maxwell, T. J. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Turner, J. [SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2015-06-22

    We report experimental studies of generating and controlling femtosecond x-ray pulses in free-electron lasers (FELs) using an emittance spoiling foil. By selectivity spoiling the transverse emittance of the electron beam, the output pulse duration or double-pulse separation is adjusted with a variable size single or double slotted foil. Measurements were performed with an X-band transverse deflector located downstream of the FEL undulator, from which both the FEL lasing and emittance spoiling effects are observed directly.

  2. Emittance minimisation with longitudinal dipole field variation

    International Nuclear Information System (INIS)

    The reduction of horizontal emittance beyond the conventional limit is pursued by introducing a longitudinal variation of the field in a bending magnet. For a given dipole field, the search for the minimal emittance is formulated analytically under different boundary conditions, starting from the achromat condition, preferred for light source rings. With a dipole field rapidly decaying along the longitudinal position, it is shown that the emittance can be further reduced, essentially by rendering the H function to be out of phase with the third power of the local curvature. Under the minimal emittance condition analytically obtained, the optimal dipole field distribution is searched numerically with a polynomial function, analysing at the same time the mechanism of the emittance reduction. The minimal emittance is argued as a function of the required peak field and the field distribution. Adaptability of longitudinally varying dipole fields in a standard magnet lattice for light sources is also addressed

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

    International Nuclear Information System (INIS)

    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

  4. Emittance-imposed alignment and frequency tolerances for the TESLA Linear Collider

    CERN Document Server

    Baboi, N

    2004-01-01

    One option in building a future 500 GeV c.m. collider is to use superconducting 1.3 GHz 9-cell cavities. Wakefields excited by the bunch train in the TESLA linac can resonantly drive the beam into unstable operation such that a BBU (Beam Break Up) mode results or at the very least significant emittance dilution occurs. The largest kick factors (proportional to the transverse fields which transversely kick the beam off axis) are found in the first three dipole bands and hence multi-bunch emittance growth is mainly determined from these bands. These higher order dipole modes are damped by carefully orientating higher order mode couplers at the downstream end of the cavities. We investigate the dilution in the emittance of a beam injected with an initial offset from the axis of the cavities. The dependence of beam emittance on systematic errors in the cell frequencies is investigated. We also vary the bunch spacing in order to simulate a systematic frequency error. While scanning the bunch spacing over a wide ra...

  5. Directional emittance corrections for thermal infrared imaging

    Science.gov (United States)

    Daryabeigi, Kamran; Wright, Robert E., Jr.; Puram, Chith K.; Alderfer, David W.

    1992-01-01

    A simple measurement technique for measuring the variation of directional emittance of surfaces at various temperatures using commercially available radiometric IR imaging systems was developed and tested. This technique provided the integrated value of directional emittance over the spectral bandwidth of the IR imaging system. The directional emittance of flat black lacquer and red stycast, an epoxy resin, measured using this technique were in good agreement with the predictions of the electromagnetic theory. The data were also in good agreement with directional emittance data inferred from directional reflectance measurements made on a spectrophotometer.

  6. Hybrid emitter all back contact solar cell

    Science.gov (United States)

    Loscutoff, Paul; Rim, Seung

    2016-04-12

    An all back contact solar cell has a hybrid emitter design. The solar cell has a thin dielectric layer formed on a backside surface of a single crystalline silicon substrate. One emitter of the solar cell is made of doped polycrystalline silicon that is formed on the thin dielectric layer. The other emitter of the solar cell is formed in the single crystalline silicon substrate and is made of doped single crystalline silicon. The solar cell includes contact holes that allow metal contacts to connect to corresponding emitters.

  7. Stochastic Boundary, Diffusion, Emittance Growth and Lifetime calculation for the RHIC e-lens

    Energy Technology Data Exchange (ETDEWEB)

    Abreu,N.P.; Fischer, W.; Luo, Y.; Robert-Demolaize, G.

    2009-01-20

    To compensate the large tune shift and tune spread generated by the head-on beam-beam interactions in polarized proton operation in the Relativistic Heavy Ion Collider (RHIC), a low energy electron beam with proper Gaussian transverse profiles was proposed to collide head-on with the proton beam. In this article, using a modified version of SixTrack [1], we investigate stability of the single particle in the presence of head-on beam-beam compensation. The Lyapunov exponent and action diffusion are calculated and compared between the cases without and with beam-beam compensation for two different working points and various bunch intensities. Using the action diffusion results the emittance growth rate and lifetime of the proton beam is also estimated for the different scenarios.

  8. Novalike Cataclysmic Variables are Significant Radio Emitters

    CERN Document Server

    Coppejans, Deanne L; Miller-Jones, James C A; Rupen, Michael P; Knigge, Christian; Sivakoff, Gregory R; Groot, Paul J

    2015-01-01

    Radio emission from non-magnetic cataclysmic variables (CVs, accreting white dwarfs) could allow detailed studies of outflows and possibly accretion flows in these nearby, numerous and non-relativistic compact accretors. Up to now, however, very few CVs have been detected in the radio. We have conducted a VLA pilot survey of four close and optically-bright novalike CVs at 6 GHz, detecting three, and thereby doubling the number of radio detections of these systems. RW Sex, V603 Aql and the old nova TT Ari were detected in both of the epochs, while V1084 Her was not detected (to a $3\\sigma$ upper-limit of 7.8 $\\mu\\rm{Jy}\\,\\rm{beam}^{-1}$). These observations clearly show that the sensitivity of previous surveys was typically too low to detect these objects and that non-magnetic CVs can indeed be significant radio emitters. The three detected sources show a range of properties, including flaring and variability on both short ($\\sim$200 s) and longer-term (days) time-scales, as well as circular polarization level...

  9. Fundamental beam-beam limit from head-on interaction in the Large Hadron Collider

    Science.gov (United States)

    Ohmi, Kazuhito; Zimmermann, Frank

    2015-12-01

    The beam-beam limit at hadron colliders manifests itself in the form of degraded luminosity lifetime and/or reduced beam lifetime. In particular, for increasing beam intensity, the nonlinear beam-beam force causes incoherent emittance growth, while the (linear) coupling force between the two colliding beams can result in coherent beam-beam instabilities. These phenomena may be enhanced (or suppressed) by lattice errors, external noise, and other perturbations. We investigate the luminosity degradation caused both by incoherent emittance growth and by coherent beam-beam instability. The resulting beam-beam limit for an ideal machine and the of question how it is affected by some of the aforementioned errors are discussed in theory and simulation.

  10. Low Emittance Gun Project based on Field Emission

    CERN Document Server

    Ganter, Romain; Dehler, M; Gobrecht, Jens; Gough, Chris; Ingold, Gerhard; Leemann, Simon C; Shing-Bruce-Li, Kevin; Paraliev, Martin; Pedrozzi, Marco; Raguin, Jean Yves; Rivkin, Leonid; Schlott, Volker; Sehr, Harald; Streun, Andreas; Wrulich, Albin F; Zelenika, Sasa

    2004-01-01

    The design of an electron gun capable of producing beam emittance one order of magnitude lower than current technology would reduce considerably the cost and size of a free electron laser emitting at 0.1nm. Field emitter arrays (FEAs) including a gate and a focusing layer are an attractive technology for such high brightness sources. Electrons are extracted from micrometric tips thanks to voltage pulses between gate and tips. The focusing layer should then reduce the initial divergence of each emitted beamlets. This FEA will be inserted in a high gradient diode configuration coupled with a radiofrequency structure. In the diode part very high electric field pulses (several hundreds of MV/m) will limit the degradation of emittance due to space charge effect. This first acceleration will be obtained with high voltage pulses (typically a megavolt in a few hundred of nanoseconds) synchronized with the low voltage pulses applied to the FEA (typically one hundred of volts in one nanosecond at frequency below kilohe...

  11. Beam tests of phosphorescent screens

    International Nuclear Information System (INIS)

    Twelve phosphorescent screens were beam tested for linearity, uniformity, low radiation damage and a suitable emitted wavelength for use with television cameras. One screen was chosen for the construction of several intercepting profile monitors which were used during the SLC Ten Sector Tests to measure the emittance and wakefield effects of a damped electron beam

  12. Emittance studies at the Los Alamos National Laboratory free electron laser

    International Nuclear Information System (INIS)

    Recent emittance studies at the Los Alamos FEL have indicated several areas of concern in the linac and beamline feeding the wiggler. These studies included both experimental measurements and computer simulations. The beamline starts with a 5 A micropulse from the thermionic cathode in the gun. After bunching by velocity modulation and acceleration to 20 MeV in a 1300 MHz standing wave accelerator, the beam current is roughly 250 A. Final bunching to 800 A is performed in the nonisochronous bend that rotates the electrons onto the axis of the wiggler and the optical cavity. Four emittance growth mechanisms of special importance have been studied. First, a rapid growth of the electron beam's emittance immediately after the spherical gridded Pierce gun resulted, in part, from the long time required for our pulsing electronics to ramp the grid voltage up at the start and down at the end of the pulse, which created a pulse with a cosine-like current distribution as a function of time. The growth was compounded by the extremely small radial beam size (almost a waist) leaving the gun. In addition, we saw evidence of electrostatic charging of the insulators in the gun, reducing the quality of the electron beam further. Second the action of the solenoidal focusing fields in the low-voltage bunching region was studied, and criteria for a minimum emittance growth were established. Third, maximum misalignment angles and displacements for various elements of the beamline were calculated for the desired low emittance growth. Finally, emittance growth in the horizontal dimensions through the nonisochronous bend caused by varying energy depression on the particles due to longitudinal wake fields was both calculated and observed. In addition, we measured energy depressions caused by the wake fields generated by various other elements in the beamline. Strategies were developed to relieve the magnitude of these wake-field effects. (orig.)

  13. Fine-tuning to minimize emittances of 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.; Asano, H.; Oguri, H. [J-PARC Center, Tokai-Mura, Naka-Gun, Ibaraki-Ken 319-1195 (Japan)

    2016-02-15

    The Japan Proton Accelerator Research Complex (J-PARC) cesiated RF-driven H{sup −} ion source has been successfully operated for about one year. By the world’s brightest level beam, the J-PARC design beam power of 1 MW was successfully demonstrated. In order to minimize the transverse emittances, the rod-filter-field (RFF) was optimized by changing the triple-gap-lengths of each of pairing five piece rod-filter-magnets. The larger emittance degradation seems to be caused by impurity-gases than the RFF. The smaller beam-hole-diameter of the extraction electrode caused the more than expected improvements on not only the emittances but also the peak beam intensity.

  14. Improved Rare-Earth Emitter Hollow Cathode

    Science.gov (United States)

    Goebel, Dan M.

    2011-01-01

    An improvement has been made to the design of the hollow cathode geometry that was created for the rare-earth electron emitter described in Compact Rare Earth Emitter Hollow Cathode (NPO-44923), NASA Tech Briefs, Vol. 34, No. 3 (March 2010), p. 52. The original interior assembly was made entirely of graphite in order to be compatible with the LaB6 material, which cannot be touched by metals during operation due to boron diffusion causing embrittlement issues in high-temperature refractory materials. Also, the graphite tube was difficult to machine and was subject to vibration-induced fracturing. This innovation replaces the graphite tube with one made out of refractory metal that is relatively easy to manufacture. The cathode support tube is made of molybdenum or molybdenum-rhenium. This material is easily gun-bored to near the tolerances required, and finish machined with steps at each end that capture the orifice plate and the mounting flange. This provides the manufacturability and robustness needed for flight applications, and eliminates the need for expensive e-beam welding used in prior cathodes. The LaB6 insert is protected from direct contact with the refractory metal tube by thin, graphite sleeves in a cup-arrangement around the ends of the insert. The sleeves, insert, and orifice plate are held in place by a ceramic spacer and tungsten spring inserted inside the tube. To heat the cathode, an insulating tube is slipped around the refractory metal hollow tube, which can be made of high-temperature materials like boron nitride or aluminum nitride. A screw-shaped slot, or series of slots, is machined in the outside of the ceramic tube to constrain a refractory metal wire wound inside the slot that is used as the heater. The screw slot can hold a single heater wire that is then connected to the front of the cathode tube by tack-welding to complete the electrical circuit, or it can be a double slot that takes a bifilar wound heater with both leads coming out

  15. Bright Single Photon Emitter in Silicon Carbide

    Science.gov (United States)

    Lienhard, Benjamin; Schroeder, Tim; Mouradian, Sara; Dolde, Florian; Trong Tran, Toan; Aharonovich, Igor; Englund, Dirk

    Efficient, on-demand, and robust single photon emitters are of central importance to many areas of quantum information processing. Over the past 10 years, color centers in solids have emerged as excellent single photon emitters. Color centers in diamond are among the most intensively studied single photon emitters, but recently silicon carbide (SiC) has also been demonstrated to be an excellent host material. In contrast to diamond, SiC is a technologically important material that is widely used in optoelectronics, high power electronics, and microelectromechanical systems. It is commercially available in sizes up to 6 inches and processes for device engineering are well developed. We report on a visible-spectrum single photon emitter in 4H-SiC. The emitter is photostable at both room and low temperatures, and it enables 2 million photons/second from unpatterned bulk SiC. We observe two classes of orthogonally polarized emitters, each of which has parallel absorption and emission dipole orientations. Low temperature measurements reveal a narrow zero phonon line with linewidth < 0.1 nm that accounts for more than 30% of the total photoluminescence spectrum. To our knowledge, this SiC color emitter is the brightest stable room-temperature single photon emitter ever observed.

  16. Beam halo studies in LEHIPA DTL

    International Nuclear Information System (INIS)

    The Low Energy High Intensity Proton Accelerator (LEHIPA) project at Bhabha Atomic Research Centre (BARC) consists of a 20 MeV, 30 mA proton linac. The accelerator comprises of a 3 MeV Radio Frequency Quadrupole (RFQ) and a 20 MeV Drift Tube Linac (DTL). In such high intensity accelerators, beam halos are of concern as they not only cause an increase in emittance, but also lead to beam loss and radio activation. We have studied the effect of beam mismatch at the DTL input on halo formation and propagation. The particle core model is used to excite the three envelope eigen modes; the quadrupole mode, the fast mode and the slow mode by giving input beam mismatch. These modes get damped as the beam progresses through the DTL. The damping mechanism is clearly Landau damping and leads to increase in rms emittance of the beam. The evolution of these modes and the corresponding increase in beam emittance and maximum beam extent, as the beam propagates through the DTL, has been studied for different space charge tunes. The halo parameter based on the definition of Allen and Wangler has been calculated. It is seen that beam halos are very important for LEHIPA DTL, even at 20 MeV and leads to emittance and beam size increase and also to beam loss in some cases. The longitudinal halo is present even without mismatch and transverse halos arise in the presence of beam mismatch

  17. Towards a Small Emittance Design of the JLEIC Electron Collider Ring

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Fanglei [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Derbenev, Yaroslav [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Hutton, Andrew M. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Morozov, Vasiliy [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Pilat, Fulvia C. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Zhang, Yuhong [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)

    2016-05-01

    The electron collider ring of the Jefferson Lab Electron-Ion Collider (JLEIC) is designed to provide an electron beam with a small beam size at the IP for collisions with an ion beam in order to reach a desired high luminosity. For a chosen beta-star at the IP, electron beam size is determined by the equilibrium emittance that can be obtained through a linear optics design. This paper briefly describes the baseline design of the electron collider ring reusing PEP-II components and considering their parameters (such as dipole sagitta, magnet field strengths and acceptable synchrotron radiation power) and reports a few approaches to reducing the equilibrium emittance in the electron collider ring.

  18. Rotating system for four-dimensional transverse rms-emittance measurements

    CERN Document Server

    Xiao, C; Du, X N; Gerhard, P; Groening, L; Mickat, S; Vormann, H

    2016-01-01

    Knowledge of the transverse four-dimensional beam rms-parameters is essential for applications that involve lattice elements that couple the two transverse degrees of freedom (planes). Of special interest is the removal of inter-plane correlations to reduce the projected emittances. A dedicated ROtating System for Emittance measurements (ROSE) has been proposed, developed, and successfully commissioned to fully determine the four-dimensional beam matrix. This device has been used at the High Charge injector (HLI) at GSI using a beam line which is composed of a skew quadrupole triplet, a normal quadrupole doublet, and ROSE. Mathematical algorithms, measurements, and results for ion beams of 83Kr13+ at 1.4 MeV/u are reported in this paper.

  19. 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

    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...

  20. TPV Systems with Solar Powered Tungsten Emitters

    International Nuclear Information System (INIS)

    A solar TPV generator development and characterization are presented. A double stage sunlight concentrator ensures 4600x concentration ratio. TPV modules based on tungsten emitters and GaSb cells were designed, fabricated and tested at indoor and outdoor conditions. The performance of tungsten emitter under concentrated solar radiation was analyzed. Emitter temperatures in the range of 1400-2000 K were measured, depending on the emitter size. The light distribution in the module has been characterized, 1x1 cm GaSb TPV cells were fabricated with the use of the Zn-diffusion and LPE technologies. The cell efficiency of 19% under illumination by a tungsten emitter (27% under spectra cut-off at λ > 1820 nm) heated up to 1900-2000 K had been derived from experimentally measured PV parameters. The series connection of PV cells was ensured by the use of BeO ceramics. The possibilities of system performance improvement are discussed

  1. Batch By Batch Longitudinal Emittance Blowup MD

    CERN Document Server

    Mastoridis, T; Butterworth, A; Jaussi, M; Molendijk, J

    2012-01-01

    The transverse bunch emittance increases significantly at 450 GeV from the time of injection till the ramp due to IBS. By selectively blowing up the longitudinal emittance of the incoming batch at each injection, it should be possible to reduce the transverse emittance growth rates due to IBS. An MD was conducted on April 22nd 2012 to test the feasibility and performance of the batch-by-batch longitudinal emittance blowup. There were three main goals during the MD. First, to test the developed hardware, firmware, and software for the batch-by-batch blowup. Then, to measure the transverse emittance growth rates of blown-up and "witness" batches to quantify any improvement, and finally to test the ALLInjectSequencer class, which deals with the complicated gymnastics of introducing or masking the new batch to various RF loops.

  2. Positron emitter labeled enzyme inhibitors

    International Nuclear Information System (INIS)

    This invention involves a new strategy for imagining and mapping enzyme activity in the living human and animal body using positron emitter-labeled suicide enzyme inactivators or inhibitors which become covalently bound to the enzyme as a result of enzymatic catalysis. Two such suicide inactivators for monoamine oxidase have been labeled with carbon-11 and used to map the enzyme subtypes in the living human and animal body using PET. By using positron emission tomography to image the distribution of radioactivity produced by the body penetrating radiation emitted by carbon-11, a map of functionally active monoamine oxidase activity is obtained. Clorgyline and L-deprenyl are suicide enzyme inhibitors and irreversibly inhibit monoamine oxidase. When these inhibitors are labeled with carbon-11 they provide selective probes for monoamine oxidase localization and reactivity in vivo using positron emission tomography

  3. Field emission behavior of carbon nanotube field emitters after high temperature thermal annealing

    Directory of Open Access Journals (Sweden)

    Yuning Sun

    2014-07-01

    Full Text Available The carbon nanotube (CNT field emitters have been fabricated by attaching a CNT film on a graphite rod using graphite adhesive material. The CNT field emitters showed much improved field emission properties due to increasing crystallinity and decreasing defects in CNTs after the high temperature thermal annealing at 900 °C in vacuum ambient. The CNT field emitters showed the low turn-on electric field of 1.15 V/μm, the low threshold electric field of 1.62 V/μm, and the high emission current of 5.9 mA which corresponds to a current density of 8.5 A/cm2. In addition, the CNT field emitters indicated the enhanced field emission properties due to the multi-stage effect when the length of the graphite rod increases. The CNT field emitter showed good field emission stability after the high temperature thermal annealing. The CNT field emitter revealed a focused electron beam spot without any focusing electrodes and also showed good field emission repeatability.

  4. Design of main linac emittance tuning bumps for the Compact Linear Collider and the International Linear Collider

    CERN Document Server

    Eliasson, Peder

    2008-01-01

    The installation of elements in the main linac of future linear colliders can only be done with a limited precision. The inevitable misalignments lead to unacceptable emittance growth. Beam-based alignment, e.g., one-to-one correction, dispersion free steering, or ballistic alignment, is necessary to reduce the emittance growth. In some cases, this is, however, not sufficient. For further reduction of the emittance growth, so-called emittance tuning bumps have to be used. A general strategy for the design of emittance tuning bumps has been developed and tested. Simulations suggest that the method can be conveniently used to understand the weaknesses of existing emittance tuning bumps and to significantly improve their performance in terms of, e.g., emittance reduction capability and convergence speed. An example of an application is the design of ten orthogonal knobs that, according to simulations, can reduce the normalized emittance growth in the Compact Linear Collider (CLIC) main linac from 23.8 to 0.34 nm...

  5. To study the emittance dilution in Superconducting Linear Accelerator Design for International Linear Collider (ILC)

    Science.gov (United States)

    Ranjan, Kirti; Solyak, Nikolay; Tenenbaum, Peter

    2005-04-01

    Recently the particle physics community has chosen a single technology for the new accelerator, opening the way for the world community to unite and concentrate resources on the design of an International Linear collider (ILC) using superconducting technology. One of the key operational issues in the design of the ILC will be the preservation of the small beam emittances during passage through the main linear accelerator (linac). Sources of emittance dilution include incoherent misalignments of the quadrupole magnets and rf-structure misalignments. In this work, the study of emittance dilution for the 500-GeV center of mass energy main linac of the Superconducting Linear Accelerator design, based on adaptation of the TESLA TDR design is performed using LIAR simulation program. Based on the tolerances of the present design, effect of two important Beam-Based steering algorithms, Flat Steering and Dispersion Free Steering, are compared with respect to the emittance dilution in the main linac. We also investigated the effect of various misalignments on the emittance dilution for these two steering algorithms.

  6. Simulations of beam-beam and beam-wire interactions in RHIC

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyung J.; Sen, Tanaji; /Fermilab; Abreu, Natalia P.; Fischer, Wolfram; /Brookhaven

    2009-02-01

    The beam-beam interaction is one of the dominant sources of emittance growth and luminosity lifetime deterioration. A current carrying wire has been proposed to compensate long-range beam-beam effects in the LHC and strong localized long-range beam-beam effects are experimentally investigated in the RHIC collider. Tune shift, beam transfer function, and beam loss rate are measured in dedicated experiments. In this paper, they report on simulations to study the effect of beam-wire interactions based on diffusive apertures, beam loss rates, and beam transfer function using a parallelized weak-strong beam simulation code (BBSIMC). The simulation results are compared with measurements performed in RHIC during 2007 and 2008.

  7. Buffer gas cooling of ion beams

    International Nuclear Information System (INIS)

    The cooling action of a buffer gas on ions contained within it can be used to cool an ion beam, thereby greatly improving its emittance and energy spread. It can also be used to greatly enhance the collection of an ion beam in an electromagnetic trap. The basic principles will be introduced in the context of a prototype system for such a beam cooler

  8. Beam dynamics issues for linear colliders

    Energy Technology Data Exchange (ETDEWEB)

    Ruth, R.D.

    1987-09-01

    In this paper we discuss various beam dynamics issues for linear colliders. The emphasis is to explore beam dynamics effects which lead to an effective dilution of the emittance of the beam and thus to a loss of luminosity. These considerations lead to various tolerances which are evaluated for a particular parameter set.

  9. Bunched Beam Cooling in the Fermilab Recycler

    CERN Document Server

    Neuffer, David V; Burov, Alexey; Nagaitsev, Sergei

    2005-01-01

    Stochastic cooling with bunched beam in a linear bucket has been obtained and implemented operationally in the fermilab recycler. In this implementation the particle bunch length is much greater than the cooling system wavelengths. The simultaneous longitudinal bunching enables cooling to much smaller longitudinal emittances than the coasting beam or barrier bucket system. Characteristics and limitations of bunched beam stochastic cooling are discussed.

  10. 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.

  11. Beam test of wire scanner beam size monitor

    International Nuclear Information System (INIS)

    A beam size monitor for emittance measurement is required to have around 10μm resolution for injector linac, and to have a few tenth μm resolution for an extracted beam from a damping ring in Accelerator Test Facility (ATF). A wire scanner is a one of the candidate of a beam size monitor with a high resolution. The design and development study of the wire scanning stage has been done. The beam test using Tohoku 300MeV Linac was done and the emittance was measured by this wire scanner. A detection of beam size signal was done by a scintillator gamma detector placed at downstream of the wire stage. All of the measurements are taken by the computer. The beam test results are described. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Yin-e

    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

  13. Multinozzle Emitter Arrays for Nanoelectrospray Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Mao, Pan; Wang, Hung-Ta; Yang, Peidong; Wang, Daojing

    2011-06-16

    Mass spectrometry (MS) is the enabling technology for proteomics and metabolomics. However, dramatic improvements in both sensitivity and throughput are still required to achieve routine MS-based single cell proteomics and metabolomics. Here, we report the silicon-based monolithic multinozzle emitter array (MEA), and demonstrate its proof-of-principle applications in high-sensitivity and high-throughput nanoelectrospray mass spectrometry. Our MEA consists of 96 identical 10-nozzle emitters in a circular array on a 3-inch silicon chip. The geometry and configuration of the emitters, the dimension and number of the nozzles, and the micropillar arrays embedded in the main channel, can be systematically and precisely controlled during the microfabrication process. Combining electrostatic simulation and experimental testing, we demonstrated that sharpened-end geometry at the stem of the individual multinozzle emitter significantly enhanced the electric fields at its protruding nozzle tips, enabling sequential nanoelectrospray for the high-density emitter array. We showed that electrospray current of the multinozzle emitter at a given total flow rate was approximately proportional to the square root of the number of its spraying-nozzles, suggesting the capability of high MS sensitivity for multinozzle emitters. Using a conventional Z-spray mass spectrometer, we demonstrated reproducible MS detection of peptides and proteins for serial MEA emitters, achieving sensitivity and stability comparable to the commercial capillary emitters. Our robust silicon-based MEA chip opens up the possibility of a fully-integrated microfluidic system for ultrahigh-sensitivity and ultrahigh-throughput proteomics and metabolomics.

  14. Final Muon Emittance Exchange in Vacuum for a Collider

    Energy Technology Data Exchange (ETDEWEB)

    Summers, Don [Univ. of Mississippi, Oxford, MS (United States); Acosta, John [Univ. of Mississippi, Oxford, MS (United States); Cremaldi, Lucien [Univ. of Mississippi, Oxford, MS (United States); Hart, Terry [Univ. of Mississippi, Oxford, MS (United States); Oliveros, Sandra [Univ. of Mississippi, Oxford, MS (United States); Perera, Lalith [Univ. of Mississippi, Oxford, MS (United States); Wu, Wanwei [Univ. of Mississippi, Oxford, MS (United States); Neuffer, David [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)

    2015-05-07

    We outline a plan for final muon ionization cooling with quadrupole doublets focusing onto short absorbers followed by emittance exchange in vacuum to achieve the small transverse beam sizes needed by a muon collider. A flat muon beam with a series of quadrupole doublet half cells appears to provide the strong focusing required for final cooling. Each quadrupole doublet has a low β region occupied by a dense, low Z absorber. After final cooling, normalized xyz emittances of (0.071, 0.141, 2.4) mm-rad are exchanged into (0.025, 0.025, 70) mm-rad. Thin electrostatic septa efficiently slice the bunch into 17 parts. The 17 bunches are interleaved into a 3.7 meter long train with RF deflector cavities. Snap bunch coalescence combines the muon bunch train longitudinally in a 21 GeV ring in 55 μs, one quarter of a synchrotron oscillation period. A linear long wavelength RF bucket gives each bunch a different energy causing the bunches to drift until they merge into one bunch and can be captured in a short wavelength RF bucket with a 13% muon decay loss and a packing fraction as high as 87%.

  15. Final Muon Emittance Exchange in Vacuum for a Collider

    CERN Document Server

    Summers, Don; Cremaldi, Lucien; Hart, Terry; Oliveros, Sandra; Perera, Lalith; Wu, Wanwei; Neuffer, David

    2015-01-01

    We outline a plan for final muon ionization cooling with quadrupole doublets focusing onto short absorbers followed by emittance exchange in vacuum to achieve the small transverse beam sizes needed by a muon collider. A flat muon beam with a series of quadrupole doublet half cells appears to provide the strong focusing required for final cooling. Each quadrupole doublet has a low beta region occupied by a dense, low Z absorber. After final cooling, normalized xyz emittances of (0.071, 0.141, 2.4) mm-rad are exchanged into (0.025, 0.025, 70) mm-rad. Thin electrostatic septa efficiently slice the bunch into 17 parts. The 17 bunches are interleaved into a 3.7 meter long train with RF deflector cavities. Snap bunch coalescence combines the muon bunch train longitudinally in a 21 GeV ring in 55 microseconds, one quarter of a synchrotron oscillation period. A linear long wavelength RF bucket gives each bunch a different energy causing the bunches to drift until they merge into one bunch and can be captured in a sho...

  16. Magnetron Driven L Band RF Gun using a Photocathode Emitter

    Science.gov (United States)

    Evans, Kirk; Fisher, Amnon; Friedman, Moshe

    1996-11-01

    Magnetron Driven L Band RF Gun using a Photocathode Emitter A tunable 5 megawatt L-Band injection locked magnetron amplifier is used to drive a 1-1/2 cell RF cavity gun, to produce a 2.5 megavolt electron beam. A tunable RF source relaxes the precision of the cavity gun construction, and therefore simplifies the design and reduces the overall cost. The design of the L-Band ( 1.3 GHz) RF cavity linear accelerator is presented, along with Superfish, SOS computer simulations, and calculations of beam energy and temporal qualities. Measurements of a few robust photocathode materials as well as measurements of the beam qualities of the final accelerator are presented. Future work will utilize new semiconductor laser diodes that can be electrically driven in the gigahertz range. This makes possible an electron gun system which can run at the RF frequency used to accelerate the electron beam. Such a system produces a "lock to clock" and synchronized RF and electron beam source which can be run single shot or any rep rate up to the RF frequency.

  17. ECR [electron cyclotron resonance] ion source beams for accelerator applications: Final report

    International Nuclear Information System (INIS)

    Reliable, easily operated ion sources are always in demand for accelerator applications. This paper reports on a systematic study of ion-beam characterisrtics and optimization of beam quality for production of light ion beams in an ECR ion source. Of particular interest is the optimization of beam brightness (defined as ion current divided by the square of the emittance), which is typically used as a figure-of-merit for accelerator-quality beams. Other areas to be discussed include the measurement of beam emittance values, the effects of various source parameters on emittances, and scaling effects from operating the same ECR source at different frequencies. 4 refs., 4 figs

  18. Noninterceptive transverse emittance measurements using BPM for Chinese ADS R&D project

    Science.gov (United States)

    Wang, Zhi-Jun; Feng, Chi; He, Yuan; Dou, Weiping; Tao, Yue; Chen, Wei-long; Jia, Huan; Liu, Shu-hui; Wang, Wang-sheng; Zhang, Yong; Wu, Jian-qiang; Zhang, Sheng-hu; Zhang, X. L.

    2016-04-01

    The noninterceptive four-dimensional transverse emittance measurements are essential for commissioning the high power continue-wave (CW) proton linacs as well as their operations. The conventional emittance measuring devices such as slits and wire scanners are not well suited under these conditions due to sure beam damages. Therefore, the method of using noninterceptive Beam Position Monitor (BPM) is developed and demonstrated on Injector Scheme II at the Chinese Accelerator Driven Sub-critical System (China-ADS) proofing facility inside Institute of Modern Physics (IMP) [1]. The results of measurements are in good agreements with wire scanners and slits at low duty-factor pulsed (LDFP) beam. In this paper, the detailed experiment designs, data analysis and result benchmarking are presented.

  19. Suppression of the emittance growth induced by coherent synchrotron radiation in triple-bend achromat

    CERN Document Server

    Huang, Xiyang; Cui, Xiaohao; Xu, Gang

    2014-01-01

    Coherent synchrotron radiation (CSR) effect at a bending path plays an important role in transverse emittance dilution in high-brightness light sources and linear colliders, where the electron beams are of short bunch length and of high peak current. Suppression of the emittance growth induced by CSR is essential and critical to preserve the beam quality and to help improve the machine performance. To evaluate the CSR effect analytically, we have proposed a novel method, which enabled us to obtain generic conditions of cancelling the CSR linear effect in a two-dipole achromat. In this paper, it illustrates that with this method the CSR-cancellation condition can be obtained for a TBA with symmetric layout, which is independent of concrete element parameters, and to a large extent, the initial beam distribution. Implementation of found condition in concrete optics design of a TBA is discussed, and the proposed condition is verified through numerical simulations.

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

    Science.gov (United States)

    Hofmann, Thomas; Boorman, Gary E.; Bosco, Alessio; Bravin, Enrico; Gibson, Stephen M.; Kruchinin, Konstantin O.; Raich, Uli; Roncarolo, Federico; Zocca, Francesca

    2016-09-01

    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 onto 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 beam 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 emittance scanner and then present results from a prototype system used during the 12 MeV commissioning of the LINAC4.

  1. Alpha-emitters for medical therapy workshop

    Energy Technology Data Exchange (ETDEWEB)

    Feinendegen, L.E.; McClure, J.J.

    1996-12-31

    A workshop on ``Alpha-Emitters for Medical Therapy`` was held May 30-31, 1996 in Denver Colorado to identify research goals and potential clinical needs for applying alpha-particle emitters and to provide DOE with sufficient information for future planning. The workshop was attended by 36 participants representing radiooncology, nuclear medicine, immunotherapy, radiobiology, molecular biology, biochemistry, radiopharmaceutical chemistry, dosimetry, and physics. This report provides a summary of the key points and recommendations arrived at during the conference.

  2. Alpha-emitters for medical therapy workshop

    International Nuclear Information System (INIS)

    A workshop on ''Alpha-Emitters for Medical Therapy'' was held May 30-31, 1996 in Denver Colorado to identify research goals and potential clinical needs for applying alpha-particle emitters and to provide DOE with sufficient information for future planning. The workshop was attended by 36 participants representing radiooncology, nuclear medicine, immunotherapy, radiobiology, molecular biology, biochemistry, radiopharmaceutical chemistry, dosimetry, and physics. This report provides a summary of the key points and recommendations arrived at during the conference

  3. Scaling laws with current for equilibrium momentum spread and emittances from intrabeam scattering and electron cooling

    International Nuclear Information System (INIS)

    Based on the theories of Piwinski, Bjorken-Mtingawa and Martini of Coulomb scattering, expressions for the heating rates due to intrabeam scattering were known since a long time. Simplifications by Wei-Parzen and Rao and Piwinski led to analytic approximations which are easily applicable to existing lattices. We use these approximations and also the formulae from thermal equilibration of Struckmeier and equate them to either constant cooling rates from electron cooling or to the Novosibirsk cooling rates for electron cooling to calculate the equilibrium values of the horizontal and vertical emittances and the momentum spread (longitudinal emittance) for typical beams in the ESR or in the HESR. For constant cooling and all approximation formulae the ratio of current to the product of the three emittances remains almost constant. This yields a slope of the momentum spread with current between 0.2 and 0.3, in agreement with experimental data. Using the Novosibirsk cooling rates this slope is much larger

  4. Radioactive beam production at the Bevalac

    International Nuclear Information System (INIS)

    At the Bevalac radioactive beams are routinely produced by the fragmentation process. The effectiveness of this process with respect to the secondary beam' emittance, intensity and energy spread depends critically on the nuclear reaction kinematics and the magnitude of the incident beam energy. When this beam energy significantly exceeds the energies of the nuclear reaction process, many of the qualities of the incident beam can be passed on the secondary beam. Factors affecting secondary beam quality are discussed along with techniques for isolating and purifying a specific reaction product. The on-going radioactive beam program at the Bevalac is used as an example with applications, present performance and plans for the future

  5. Experimental study of proton beam halo in mismatched beams

    International Nuclear Information System (INIS)

    We report measurements of transverse beam-halo formation in mismatched proton beams in a 52-quadrupole FODO-transport channel following the 6.7 MeV RFQ at the Low-Energy Demonstration Accelerator (LEDA) at Los Alamos. Beam profiles in both transverse planes were measured using a new diagnostic device that consists of a movable carbon filament for measurement of the beam core, and scraper plates for measurement of the outer part of the distributions. The initial results indicate a surprisingly strong growth rate of the rms emittance even for the modest space-charge tune depressions of the experiment. Our results are consistent with the complete transfer of free energy of the mismatched beams into emittance growth within 10 envelope oscillations for both the breathing and the quadrupole modes.

  6. Summary from working group on multiple beams and funneling

    International Nuclear Information System (INIS)

    The working group on Multiple Beams and Funneling discussed various topics related to multiple beams and funneling, including (1) design considerations for multiple-beam accelerators; (2) scaling of current, emittance, and brightness for multiple-beam systems; (3) funneling lines using either discrete components or a radiofrequency quadrupole (RFQ) funneling structure; and (4) alternatives to funneling

  7. Luminosity dilution due to random offset beam-beam interaction

    International Nuclear Information System (INIS)

    We consider beam-beam interaction in a collider in the case when the beams randomly displace around the equilibrium orbit at the interaction point. Due to the random part of the interaction, particles diffuse over the betatron amplitude causing an emittance growth of the beam. A Fokker-Planck equation is derived in which a diffusion coefficient is related with the spectral density of the noise. Estimations for the Superconducting Super Collider parameters give a tolerable level of the high-frequency beam offset at the interaction point. 2 refs

  8. Improving Touschek lifetime in ultralow-emittance lattices through systematic application of successive closed vertical dispersion bumps

    Science.gov (United States)

    Breunlin, J.; Leemann, S. C.; Andersson, Å.

    2016-06-01

    In present ultralow-emittance storage ring designs the emittance coupling required for the production of vertically diffraction-limited synchrotron radiation in the hard x-ray regime is achieved and in many cases surpassed by a correction of the orbit and the linear optics alone. However, operating with a vertical emittance lower than required is disadvantageous, since it decreases Touschek lifetime and reduces brightness due to the transverse emittance increase from intrabeam scattering. In this paper we present a scheme consisting of closed vertical dispersion bumps successively excited in each arc of the storage ring by skew quadrupoles that couple horizontal dispersion into the vertical plane to a desired level and thereby raise the vertical emittance in a controlled fashion. A systematic approach to vertical dispersion bumps has been developed that suppresses dispersion and betatron coupling in the straight sections in order to maintain a small projected emittance for insertion devices. In this way, beam lifetime can be significantly increased without negatively impacting insertion device source properties and hence brightness. Using simulation results for the MAX IV 3 GeV storage ring including magnet and alignment imperfections we demonstrate that Touschek lifetime can be increased by more than a factor 2 by adjusting the vertical emittance from 1.3 pm rad (after orbit correction) to 8 pm rad (after application of dispersion bumps) using two to three independent skew quadrupole families all the while ensuring deviations from design optics are restrained to a minimum.

  9. [Simulation of ultra-low emittance electron storage]. Performance report for period December 1, 1985-present

    International Nuclear Information System (INIS)

    A set of programs has been developed which can be used to design and simulate damping rings with tune values up to 1000 or more. The simulation program XSIM has been run to determine the beam emittances of model acceleration. Another accomplishment reported is the invention of the idea of laser cooling of an electron beam. A high peak power laser beam is focused on an electron beam in a storage ring straight section containing an undulator. The undulator period and magnetic field are chosen so that the average energy of the electron beam coincides with the resonant energy of the undulator-laser combination. The energy distribution of electrons is thus narrowed and the beam is cooled

  10. Beam-beam observations in the Relativistic Heavy Ion Collider

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Y. [Brookhaven National Laboratory (BNL), Upton, NY (United States); Fischer, W. [Brookhaven National Laboratory (BNL), Upton, NY (United States); White, S. [Brookhaven National Laboratory (BNL), Upton, NY (United States)

    2015-06-24

    The Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory has been operating since 2000. Over the past decade, thanks to the continuously increased bunch intensity and reduced β*s at the interaction points, the maximum peak luminosity in the polarized proton operation has been increased by more than two orders of magnitude. In this article, we first present the beam-beam observations in the previous RHIC polarized proton runs. Then we analyze the mechanisms for the beam loss and emittance growth in the presence of beam-beam interaction. The operational challenges and limitations imposed by beam-beam interaction and their remedies are also presented. In the end, we briefly introduce head-on beam-beam compensation with electron lenses in RHIC.

  11. Three-dimensional theory of emittance in Compton scattering and x-ray protein crystallography

    International Nuclear Information System (INIS)

    A complete, three-dimensional theory of Compton scattering is described, which fully takes into account the effects of the electron beam emittance and energy spread upon the scattered x-ray spectral brightness. The radiation scattered by an electron subjected to an arbitrary electromagnetic field distribution in vacuum is first derived in the linear regime, and in the absence of radiative corrections; it is found that each vacuum eigenmode gives rise to a single Doppler-shifted classical dipole excitation. This formalism is then applied to Compton scattering in a three-dimensional laser focus, and yields a complete description of the influence of the electron beam phase-space topology on the x-ray spectral brightness; analytical expressions including the effects of emittance and energy spread are also obtained in the one-dimensional limit. Within this framework, the x-ray brightness generated by a 25 MeV electron beam is modeled, fully taking into account the beam emittance and energy spread, as well as the three-dimensional nature of the laser focus; its application to x-ray protein crystallography is outlined. Finally, coherence, harmonics, and radiative corrections are also briefly discussed

  12. Enhancing the accelerated beam current in the booster synchrotron by optimizing the transport line beam propagation

    Indian Academy of Sciences (India)

    Saini R S; Tyagi Y; Ghodke A D; Puntambekar T A

    2016-04-01

    In this paper, we present the results of transverse beam emittance and twiss parameter measurement of an electron beam, delivered by a 20 MeV microtron which is used as a pre-injector system for a booster synchrotron in the Indus Accelerator Facility at RRCAT Indore. Based on these measured beam parameters, beam optics of a transport line was optimized and its results are alsodiscussed in this paper. This beam transport line is used to transport the electron beam from the 20MeV microtron to the booster synchrotron. The booster synchrotron works as a main injector for Indus-1 and Indus-2 synchrotron radiation facilities. To optimize the beam optics of a transport linefor proper beam transmission through the line as well as to match the beam twiss parameters at the beam injection point of another accelerator, it is necessary to know the transverse beam emittance and twiss parameters of the beam coming from the first one. A MATLAB-based GUI program has been developed to calculate the beam emittance and twiss parameters, using quadrupole scanmethod. The measured parameters have been used for beam transport line optimization and twiss parameters matching at booster injection point. After this optimization, an enhancement of ∼50% beam current has been observed in the booster synchrotron.

  13. A Design Report of the Baseline for PEP-X: an Ultra-Low Emittance Storage Ring

    Energy Technology Data Exchange (ETDEWEB)

    Bane, Karl; Bertsche, Kirk; Cai, Yunhai; Chao, Alex; Corbett, Willian; Fox, John; Hettel, Robert; Huang, Xiaobiao; Huang, Zhirong; Ng, Cho-Kuen; Nosochkov, Yuri; Novokhatski, Sasha; Radedeau, Thomas; Raubenheimer, Tor; Rivetta, Claudio; Safranek, James; Seeman, John; Stohr, Joachim; Stupakov, Gennady; Wang, Lanfa; Wang, Min-Huey; /SLAC

    2010-06-02

    Over the past year, we have worked out a baseline design for PEP-X, as an ultra-low emittance storage ring that could reside in the existing 2.2-km PEPII tunnel. The design features a hybrid lattice with double bend achromat (DBA) cells in two arcs and theoretical minimum emittance (TME) cells in the remaining four arcs. Damping wigglers are used to reduce the horizontal emittance to 86 pm-rad at zero current for a 4.5 GeV electron beam. At a design current of 1.5 A, the horizontal emittance increases, due to intrabeam scattering, to 164 pm-rad when the vertical emittance is maintained at a diffraction limited 8 pm-rad. The baseline design will produce photon beams achieving a brightness of 10{sup 22} (ph/s/mm{sup 2}/mrad{sup 2}/0.1% BW) at 10 keV in a 3.5-m conventional planar undulator. Our study shows that an optimized lattice has adequate dynamic aperture, while accommodating a conventional off-axis injection system. In this report, we present the results of study, including the lattice properties, nonlinear dynamics, intra-beam scattering and Touschek lifetime, RF system, and collective instabilities. Finally, we discuss the possibility of partial lasing at soft X-ray wavelengths using a long undulator in a straight section.

  14. Consequences of bounds on longitudinal emittance growth for the design of recirculating linear accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Berg, J. S. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.

    2015-05-03

    Recirculating linear accelerators (RLAs) are a cost-effective method for the acceleration of muons for a muon collider in energy ranges from a couple GeV to a few 10s of GeV. Muon beams generally have longitudinal emittances that are large for the RF frequency that is used, and it is important to limit the growth of that longitudinal emittance. This has particular consequences for the arc design of the RLAs. I estimate the longitudinal emittance growth in an RLA arising from the RF nonlinearity. Given an emittance growth limitation and other design parameters, one can then compute the maximum momentum compaction in the arcs. I describe how to obtain an approximate arc design satisfying these requirements based on the deisgn in [1]. Longitudinal dynamics also determine the energy spread in the beam, and this has consequences on the transverse phase advance in the linac. This in turn has consequences for the arc design due to the need to match beta functions. I combine these considerations to discuss design parameters for the acceleration of muons for a collider in an RLA from 5 to 63 GeV.

  15. Diamond-based single-photon emitters

    International Nuclear Information System (INIS)

    The exploitation of emerging quantum technologies requires efficient fabrication of key building blocks. Sources of single photons are extremely important across many applications as they can serve as vectors for quantum information-thereby allowing long-range (perhaps even global-scale) quantum states to be made and manipulated for tasks such as quantum communication or distributed quantum computation. At the single-emitter level, quantum sources also afford new possibilities in terms of nanoscopy and bio-marking. Color centers in diamond are prominent candidates to generate and manipulate quantum states of light, as they are a photostable solid-state source of single photons at room temperature. In this review, we discuss the state of the art of diamond-based single-photon emitters and highlight their fabrication methodologies. We present the experimental techniques used to characterize the quantum emitters and discuss their photophysical properties. We outline a number of applications including quantum key distribution, bio-marking and sub-diffraction imaging, where diamond-based single emitters are playing a crucial role. We conclude with a discussion of the main challenges and perspectives for employing diamond emitters in quantum information processing.

  16. Integrated photonic crystal selective emitter for thermophotovoltaics

    Science.gov (United States)

    Zhou, Zhiguang; Yehia, Omar; Bermel, Peter

    2016-01-01

    Converting blackbody thermal radiation to electricity via thermophotovoltaics (TPV) is inherently inefficient. Photon recycling using cold-side filters offers potentially improved performance but requires extremely close spacing between the thermal emitter and the receiver, namely a high view factor. Here, we propose an alternative approach for thermal energy conversion, the use of an integrated photonic crystal selective emitter (IPSE), which combines two-dimensional photonic crystal selective emitters and filters into a single device. Finite difference time domain and current transport simulations show that IPSEs can significantly suppress sub-bandgap photons. This increases heat-to-electricity conversion for photonic crystal based emitters from 35.2 up to 41.8% at 1573 K for a GaSb photovoltaic (PV) diode with matched bandgaps of 0.7 eV. The physical basis of this enhancement is a shift from a perturbative to a nonperturbative regime, which maximized photon recycling. Furthermore, combining IPSEs with nonconductive optical waveguides eliminates a key difficulty associated with TPV: the need for precise alignment between the hot selective emitter and cool PV diode. The physical effects of both the IPSE and waveguide can be quantified in terms of an extension of the concept of an effective view factor.

  17. Variable emittance behavior of smart radiative coating

    Science.gov (United States)

    Guo, Li; Fan, Desong; Li, Qiang

    2016-02-01

    Smart radiative coating on yttria stabilized zirconia (YSZ) substrate was prepared by the sol-gel La{}1-xSr x MnO3 (x = 0.125, 0.175 and 0.2) nanoparticles and the binder composed of terpineol and ethyl cellulose. The crystallized structure, grain size, chemical compositions, magnetization and the surface morphology were characterized. The thermal radiative properties of coating in the infrared range was evaluated from infrared reflectance spectra at various temperatures. A single perovskite structure is detected in sol-gel nanoparticles with size 200 nm. Magnetization measurement reveals that room temperature phase transition samples can be obtained by appropriate Sr substitution. The influence of surface conditions and sintering temperature on the emittance of coating was observed. For rough coatings with root-mean-square roughness 640 nm (x = 0.125) and 800 nm (x = 0.175) , its emittance increment is 0.24 and 0.26 in in the temperature range of 173-373 K. Increasing sintering temperature to 1673 K, coating emittance variation improves to 0.3 and 0.302 respectively. After mechanical polishing treatment, the emittance increment of coatings are enhanced to 0.31 and 0.3, respectively. The results suggested that the emittance variation can be enhanced by reducing surface roughness and increasing sintering temperature of coating.

  18. Extension of the general thermal field equation for nanosized emitters

    Energy Technology Data Exchange (ETDEWEB)

    Kyritsakis, A., E-mail: akyritsos1@gmail.com; Xanthakis, J. P. [Department of Electrical and Computer Engineering, National Technical University of Athens, Zografou Campus, Athens 15700 (Greece)

    2016-01-28

    During the previous decade, Jensen et al. developed a general analytical model that successfully describes electron emission from metals both in the field and thermionic regimes, as well as in the transition region. In that development, the standard image corrected triangular potential barrier was used. This barrier model is valid only for planar surfaces and therefore cannot be used in general for modern nanometric emitters. In a recent publication, the authors showed that the standard Fowler-Nordheim theory can be generalized for highly curved emitters if a quadratic term is included to the potential model. In this paper, we extend this generalization for high temperatures and include both the thermal and intermediate regimes. This is achieved by applying the general method developed by Jensen to the quadratic barrier model of our previous publication. We obtain results that are in good agreement with fully numerical calculations for radii R > 4 nm, while our calculated current density differs by a factor up to 27 from the one predicted by the Jensen's standard General-Thermal-Field (GTF) equation. Our extended GTF equation has application to modern sharp electron sources, beam simulation models, and vacuum breakdown theory.

  19. Extension of the general thermal field equation for nanosized emitters

    International Nuclear Information System (INIS)

    During the previous decade, Jensen et al. developed a general analytical model that successfully describes electron emission from metals both in the field and thermionic regimes, as well as in the transition region. In that development, the standard image corrected triangular potential barrier was used. This barrier model is valid only for planar surfaces and therefore cannot be used in general for modern nanometric emitters. In a recent publication, the authors showed that the standard Fowler-Nordheim theory can be generalized for highly curved emitters if a quadratic term is included to the potential model. In this paper, we extend this generalization for high temperatures and include both the thermal and intermediate regimes. This is achieved by applying the general method developed by Jensen to the quadratic barrier model of our previous publication. We obtain results that are in good agreement with fully numerical calculations for radii R > 4 nm, while our calculated current density differs by a factor up to 27 from the one predicted by the Jensen's standard General-Thermal-Field (GTF) equation. Our extended GTF equation has application to modern sharp electron sources, beam simulation models, and vacuum breakdown theory

  20. Simulation of Head-on Beam-Beam Limitations in Future High Energy Colliders

    CERN Document Server

    Buffat, Xavier; Florio, Adrien; Pieloni, Tatiana; Tambasco, Claudia

    2016-01-01

    The Future Circular Hadron Collider (FCC-hh) project calls for studies in a new regime of beam-beam interactions. While the emittance damping due to synchrotron radiation is still slower than in past or existing lepton colliders, it is significantly larger than in other hadron colliders. The slow reduction of the emittance is profitable for higher luminosity in term of transverse beam size at the interaction points and also to mitigate long-range beam-beam effects, potentially allowing for a reduction of the crossing angle between the beams during the operation. In such conditions, the strength of head-on beam-beam interactions increases, potentially limiting the beam brightness. 4D weak-strong and strong-strong simulations are performed in order to assess these limitations.

  1. Recent Advances in Beam Diagnostic Techniques

    Science.gov (United States)

    Fiorito, R. B.

    2002-12-01

    We describe recent advances in diagnostics of the transverse phase space of charged particle beams. The emphasis of this paper is on the utilization of beam-based optical radiation for the precise measurement of the spatial distribution, divergence and emittance of relativistic charged particle beams. The properties and uses of incoherent as well as coherent optical transition, diffraction and synchrotron radiation for beam diagnosis are discussed.

  2. Resonant Laser Cooling of Circular Accelerator Beams

    OpenAIRE

    Tumanian, R. V.

    2004-01-01

    The resonant laser cooling of circular accelerator beams of relativistic charged particle is studied. It is shown that in the approximation of the given external electromagnetic wave amplitude (small gain free electron laser) the emittance of a beam of charged particles decreases. In the field of particle energy about 100 in the mass energy units the beam energy losses are negligible. The discovered effect can be used for cooling of charged particle beams in various accelerators. The signific...

  3. Optimized aperiodic highly directional narrowband infrared emitters

    Science.gov (United States)

    Granier, Christopher H.; Afzal, Francis O.; Min, Changjun; Dowling, Jonathan P.; Veronis, Georgios

    2014-09-01

    Bulk thermal emittance sources possess incoherent, isotropic, and broadband radiation spectra that vary from material to material. However, these radiation spectra can be drastically altered by modifying the geometry of the structures. In particular, several approaches have been proposed to achieve narrowband, highly directional thermal emittance based on photonic crystals, gratings, textured metal surfaces, metamaterials, and shock waves propagating through a crystal. Here we present optimized aperiodic structures for use as narrowband, highly directional thermal infrared emitters for both TE and TM polarizations. One-dimensional layered structures without texturing are preferable to more complex two- and three-dimensional structures because of the relative ease and low cost of fabrication. These aperiodic multilayer structures designed with alternating layers of silicon and silica on top of a semi-infinite tungsten substrate exhibit extremely high emittance peaked around the wavelength at which the structures are optimized. Structures were designed by a genetic optimization algorithm coupled to a transfer matrix code which computed thermal emittance. First, we investigate the properties of the genetic-algorithm optimized aperiodic structures and compare them to a previously proposed resonant cavity design. Second, we investigate a structure optimized to operate at the Wien wavelength corresponding to a near-maximum operating temperature for the materials used in the aperiodic structure. Finally, we present a structure that exhibits nearly monochromatic and highly directional emittance for both TE and TM polarizations at the frequency of one of the molecular resonances of carbon monoxide (CO); hence, the design is suitable for a detector of CO via absorption spectroscopy.

  4. Spectral Emittance of Uncoated and Ceramic-Coated Inconel and Type 321 Stainless Steel

    Science.gov (United States)

    Richmond, Joseph C.; Stewart, James E.

    1959-01-01

    The normal spectral emittance of Inconel and type 321 stainless steel with different surface treatments was measured at temperatures of 900, 1,200, 1,500, and 1,800 F over a wavelength range of 1.5 to 15 microns. The measurements involved comparison of the radiant energy emitted by the heated specimen with that emitted by a comparison standard at the same temperature by means of a recording double-beam infrared spectrophotometer. The silicon carbide comparison standard had previously been calibrated against a laboratory black-body furnace. Surface treatments included electropolishing, sandblasting, electro-polishing followed by oxidation in air for 1/2 hour at 1,800 F, sandblasting followed by oxidation in air for 1/2 hour at 1,800 F, application of National Bureau of Standards coating A-418, and application of NBS ceramic coating N-143. The normal spectral emittance of both alloys in the electropolished condition was low and decreased very slightly with increasing wavelength while in the sandblasted condition it was somewhat higher and did not vary appreciably with wavelength. The oxidation treatment greatly increased the normal spectral emittance of both the electropolished and sandblasted type 321 stainless steel specimens and of the electropolished Inconel specimens and introduced some spectral selectivity into the curves. The oxidation increased the normal spectral emittance of the sandblasted Inconel specimens only moderately. Of the specimens to which a coating about 0.002 inch thick was applied, those coated with A-418 had higher emittance at all wavelengths than did those coated with N-143, and the coated specimens of Inconel had higher spectral emittance at all wavelengths than did the corresponding specimens of type 321 stainless steel. Both coatings were found to be partially transparent to the emitted energy at this thickness but essentially opaque at a thickness of 0.005 inch. Coated specimens with 0.005 inch or more of coating did not show the effect

  5. Real-time transverse-emittance and phase-space monitor

    Science.gov (United States)

    Song, J.; Piot, P.; Legg, R.; Kehne, D.; Li, R.; Feldl, E.; Jordan, K.; Denard, J.-C.; Krafft, G. A.; Neil, G. R.; Bohn, C. L.

    1998-02-01

    A real-time multislit [1]transverse-emittance monitor has been developed for diagnosing the space-charge-dominated beam in the 10 MeV injection line of the FEL at Thomas Jefferson National Accelerator Facility (formerly CEBAF). It gives emittance, Twiss parameters, and phase-space contours (without any symmetry assumptions) at the update rate of 1 Hz. It reduces measurement noise in real-time, and incorporates a special algorithm for constructing the phase-space matrix, which yields more accurate results by sweeping the beam across the slits. In this paper we will discuss issues relevant to the software design and implementation. Experimental results obtained from a 250 keV photocathode gun will also be presented and compared with other methods and with PARMELA simulations.

  6. Simulated Emittance Growth due to Electron Cloud for SPS and LHC

    CERN Document Server

    Benedetto, Elena; Schulte, Daniel; Zimmermann, Frank

    2004-01-01

    The emittance growth caused by an electron cloud is simulated by the HEADTAIL code with conducting boundary conditions. Under some conditions the simulation results may depend on the number of beam-cloud interaction points, the phase advance between them and the number of macroparticles used to represent beam and cloud. Simulations include a transverse feedback system and, optionally, a large chromaticity, as employed in actual SPS operation. Simulation results for the SPS can be compared with observations, and the emittance growth in the LHC is computed as a function of average electron density. An attempt is made to extrapolate to low electron densities. We also compare the initial instability rise times with those obtained for an equivalent broadband resonator.

  7. Studies and calculations of transverse emittance growth in high-energy proton storage rings

    International Nuclear Information System (INIS)

    In the operation of proton-antiproton colliders, an important goal is to maximize the integrated luminosity. During such operations in the Fermilab Tevatron, the transverse beam emittances were observed to grow unexpectedly quickly, thus causing a serious reduction of the luminosity. We have studied this phenomenon experimentally and theoretically. A formula for the emittance growth rate, due to random dipole kicks, is derived. In the experiment, RF phase noise of known amplitude was deliberately injected into the Tevatron to kick the beam randomly, via dispersion at the RF cavities. Theory and experiment are found to agree reasonably well. We also briefly discuss the problem of quadrupole kicks. 14 refs., 2 figs., 3 tabs

  8. Emittance growth and energy loss due to coherent synchrotron radiation in a bunch compressor

    International Nuclear Information System (INIS)

    Electron bunches of high charge (up to 10 nC) are compressed in length in the Compact Linear Collider Test Facility magnetic chicane to less than 0.4 mm rms. The short bunches radiate coherently in the chicane magnetic field, and the horizontal and longitudinal phase space density distributions are affected. This paper reports the results of beam emittance and momentum measurements. Horizontal and vertical emittances and momentum spectra were measured for different bunch compression factors and bunch charges. In particular, for 10 nC bunches, the mean beam momentum decreased by about 5% while the rms momentum spread increased from 2% to 8%. The experimental results are compared with simulations made with the code TRAFIC4

  9. An ultimate storage ring lattice with vertical emittance generated by damping wigglers

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Xiaobiao [SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States)

    2015-01-06

    We discuss the approach of generating round beams for ultimate storage rings using vertical damping wigglers (with horizontal magnetic field). The vertical damping wigglers provide damping and excite vertical emittance. This eliminates the need to generate large linear coupling that is impractical with traditional off-axis injection. We use a PEP-X compatible lattice to demonstrate the approach. This lattice uses separate quadrupole and sextupole magnets with realistic gradient strengths. Intrabeam scattering effects are calculated. As a result, the horizontal and vertical emittances are 22.3 pm and 10.3 pm, respectively, for a 200 mA, 4.5 GeV beam, with a vertical damping wiggler of a total length of 90 m, a peak field of 1.5 T and a wiggler period of 100 mm.

  10. Methods for measuring sub-pm rad vertical emittance at the Swiss Light Source

    Science.gov (United States)

    Breunlin, J.; Andersson, Å.; Milas, N.; Saá Hernández, Á.; Schlott, V.

    2015-12-01

    We report on methods capable of measuring a rms vertical electron beam size of 3 μm with a rms error of less than 10% at a diagnostic beamline at the Swiss Light Source (SLS). This corresponds to a vertical emittance of 0.6 pm rad with a 20% rms error. We showed this capability by presenting the theoretical basis for, and the data from, a series of measurements on a stable beam at 1.6 pm rad vertical emittance at the SLS. The methods presented utilized either π- or σ-polarized synchrotron radiation (SR) in the visible to ultra violet (vis-UV) spectral range. In addition to the established π-polarization method, we introduced a diffraction method with a potentially high resolution capability. Also an intensity imbalanced diffraction scheme was introduced, but was found to be prone to SR induced carbon contamination on optical elements.

  11. Design of a low emittance and high repetition rate S-band photoinjector

    Science.gov (United States)

    Han, Jang-Hui

    2014-09-01

    As an electron beam injector of X-ray free-electron lasers (FELs), photoinjectors have been developed for the past few decades. Such an injector starting with a photocathode RF gun provides high brightness beams and therefore it is being adopted as an injector of X-ray FELs. In this paper we show how to improve photoinjector performance in terms of emittance and repetition rates by means of injector components optimization, especially with the gun. Transverse emittance at the end of an injector is reduced by optimizing the gun design, gun solenoid position, and accelerating section position. The repetition rate of an injector mainly depends on the gun. It is discussed that a repetition rate of 1 kHz at a normal-conducting S-band photoinjector is feasible by adopting a coaxial RF coupler and improving cooling-water channels surrounding the gun.

  12. Coupling single emitters to quantum plasmonic circuits

    CERN Document Server

    Huck, Alexander

    2016-01-01

    In recent years the controlled coupling of single photon emitters to propagating surface plasmons has been intensely studied, which is fueled by the prospect of a giant photonic non-linearity on a nano-scaled platform. In this article we will review the recent progress on coupling single emitters to nano-wires towards the construction of a new platform for strong light-matter interaction. The control over such a platform might open new doors for quantum information processing and quantum sensing at the nanoscale, and for the study of fundamental physics in the ultra-strong coupling regime.

  13. Research on Radar Emitter Attribute Recognition Method

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    In order to solve emitter recognition problems in a practical reconnaissance environment, attribute mathematics is introduced. The basic concepts and theory of attribute set and attribute measure are described in detail. A new attribute recognition method based on attribute measure is presented in this paper. Application example is given, which demonstrates this new method is accurate and effective. Moreover, computer simulation for recognizing the emitter purpose is selected, and compared with classical statistical pattern recognition through simulation. The excellent experimental results demonstrate that this is a brand-new attribute recognition method as compared to existing statistical pattern recognition techniques.

  14. An Observation of a Transverse to Longitudinal Emittance Exchange at the Fermilab A0 Photoinjector

    Energy Technology Data Exchange (ETDEWEB)

    Koeth, Timothy W.; /Rutgers U., Piscataway

    2009-05-01

    An experimental program to perform a proof of principle of transverse to longitudinal emittance exchange ({epsilon}{sub x{sub in}} {Leftrightarrow} {epsilon}{sub z{sub out}} and {epsilon}{sub z{sub in}} {Leftrightarrow} {epsilon}{sub x{sub out}}) has been developed at the Fermilab A0 Photoinjector. A new beamline, including two magnetic dogleg channels and a TM{sub 110} 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 x{sub in}, x'{sub in}, y{sub in}, y'{sub in}, z{sub in}, or {delta}{sub in}, and measuring the changes in all of the beam output vector's elements, x{sub out}, x'{sub out}, y{sub out}, y'{sub out}, z{sub out}, {delta}{sub out}, 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, {epsilon}{sub z{sub in}} of 21.1 {+-} 1.5 mm{center_dot}mrad was observed to be exchanged with {epsilon}{sub x{sub out}} of 20.8 {+-} 2.00 mm{center_dot}mrad. Diagnostic limitations in the {epsilon}{sub z{sub out}} measurement did not account for an energy-time correlation, thus potentially returning values larger than the actual longitudinal emittance. The {epsilon}{sub x{sub in}} of 4.67 {+-} 0.22 mm{center_dot}mrad was observed to be exchanged with {epsilon}{sub z{sub out}} of 7.06 {+-} 0.43 mm{center_dot}mrad. The apparent {epsilon}{sub z{sub out}} growth is consistent with calculated values in which the correlation term is neglected.

  15. Electron-beam dynamics for an advanced flash-radiography accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Ekdahl, Carl August Jr. [Los Alamos National Laboratory

    2015-06-22

    Beam dynamics issues were assessed for a new linear induction electron accelerator. Special attention was paid to equilibrium beam transport, possible emittance growth, and beam stability. Especially problematic would be high-frequency beam instabilities that could blur individual radiographic source spots, low-frequency beam motion that could cause pulse-to-pulse spot displacement, and emittance growth that could enlarge the source spots. Beam physics issues were examined through theoretical analysis and computer simulations, including particle-in cell (PIC) codes. Beam instabilities investigated included beam breakup (BBU), image displacement, diocotron, parametric envelope, ion hose, and the resistive wall instability. Beam corkscrew motion and emittance growth from beam mismatch were also studied. It was concluded that a beam with radiographic quality equivalent to the present accelerators at Los Alamos will result if the same engineering standards and construction details are upheld.

  16. Electron beam experiments at Maryland University

    International Nuclear Information System (INIS)

    An experimental study of the stability of intense electron beams is described. The purpose is to determine the emittance growth associated with aberrations arising from the non-uniform transverse density distribution in the beam, and to compare measurements with the results of computer simulations

  17. Bunch Compressor for Beam-Based Alignment

    CERN Document Server

    Latina, A; Schulte, D

    2007-01-01

    Misalignments in the main linac of future linear colliders can lead to significant emittance growth. Beam-based alignment algorithms, such as Dispersion Free Steering (DFS), are necessary to mitigate these effects. We study how to use the Bunch Compressor to create the off-energy beams necessary for DFS and discuss the effectiveness of this method.

  18. High current beam transport with multiple beam arrays

    International Nuclear Information System (INIS)

    Highlights of recent experimental and theoretical research progress on the high current beam transport of single and multiple beams by the Heavy Ion Fusion Accelerator Research (HIFAR) group at the Lawrence Berkeley Laboratory (LBL) are presented. In the single beam transport experiment (SBTE), stability boundaries and the emittance growth of a space charge dominated beam in a long quadrupole transport channel were measured and compared with theory and computer simulations. Also, a multiple beam ion induction linac (MBE-4) is being constructed at LBL which will permit study of multiple beam transport arrays, and acceleration and bunch length compression of individually focused beamlets. Various design considerations of MBE-4 regarding scaling laws, nonlinear effects, misalignments, and transverse and longitudinal space charge effects are summarized. Some aspects of longitudinal beam dynamics including schemes to generate the accelerating voltage waveforms and to amplify beam current are also discussed

  19. A scintillator based time-of-flight hodoscope with a new type of emitter follower divider

    International Nuclear Information System (INIS)

    A high precision, time-of-flight hodoscope has been constructed to analyse the secondary pion beam at GSI, Darmstadt. The hodoscope comprises three scintillator planes with the individual scintillator rods read out by photomultipliers in both ends. A new active base of the emitter follower type has been developed for stabilization of voltages at the last dynodes of the photomultiplier. The time resolution of this system was found to be σ=<150ps for counting rates up to 2MHz

  20. Implications of longitudinal emittance dilution for HIF storage ring driver schemes

    International Nuclear Information System (INIS)

    The role is discussed of transverse and longitudinal emittance dilutions during the injection, debunching, compression, extraction and transport stages in storage rings for HIF drivers. The question of dilution effects at the space-charge levels is also considered. Possible storage ring schemes are examined and arrangements for bunch compression rings and final beam lines considered. Limitations on possible designs due to dilution effects are given. (U.K.)

  1. 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. PMID:22380182

  2. Thermo-mechanical design of a CW sweep plate emittance scanner

    International Nuclear Information System (INIS)

    A sweep plate emittance scanner for use with high power, continuous wave (CW) beams has been designed, fabricated and commissioned at Northrop Grumman. The design is capable of scanning beams of up to 20 kW beam power with a spot diameter as small as 2 cm. The scanner pod is mounted on a ball screw driven linear bearing table that is driven through the beam by a stepper motor at velocities up to 30 cm/sec. This paper presents the thermo-mechanical analysis of the pod moving through a gaussian beam and the details of the mechanical design of the pod and motion system. Analyses to determine scanner cooling schemes and structural materials are presented. (author)

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

    Institute of Scientific and Technical Information of China (English)

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

    2013-01-01

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

  4. Beam-Beam Effects

    OpenAIRE

    Herr, W; Pieloni, T.

    2016-01-01

    One of the most severe limitations in high-intensity particle colliders is the beam-beam interaction, i.e. the perturbation of the beams as they cross the opposing beams. This introduction to beam-beam effects concentrates on a description of the phenomena that are present in modern colliding beam facilities.

  5. Beam-Beam Effects

    CERN Document Server

    Herr, W

    2014-01-01

    One of the most severe limitations in high-intensity particle colliders is the beam-beam interaction, i.e. the perturbation of the beams as they cross the opposing beams. This introduction to beam-beam effects concentrates on a description of the phenomena that are present in modern colliding beam facilities.

  6. Micromachining using focused ion beams

    International Nuclear Information System (INIS)

    Focused ion beam (FIB) systems prove to be useful precision micromachining tools for a wide variety of applications. This micromachining technique includes scanning ion microscopy (SIM), micromachining by physical sputtering, and the ion-beam induced surface chemistry for etching and deposition. This technique is applied to image and modify IC's, to micromechanical applications, to modify the tip shape of tungsten emitters, and to prepare cross sections of selected regions for inspection in a transmission electron microscope (TEM). (orig.)

  7. Low energy beam transport system developments

    International Nuclear Information System (INIS)

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

  8. Low energy beam transport system developments

    Science.gov (United States)

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

    2015-04-01

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

  9. Microfabricated electrospray emitter arrays with integrated extractor and accelerator electrodes for the propulsion of small spacecraft

    International Nuclear Information System (INIS)

    Microfabricated electrospray thrusters could revolutionize the spacecraft industry by providing efficient propulsion capabilities to micro and nano satellites (1–100 kg). We present the modeling, design, fabrication and characterization of a new generation of devices, for the first time integrating in the fabrication process individual accelerator electrodes capable of focusing and accelerating the emitted sprays. Integrating these electrodes is a key milestone in the development of this technology; in addition to increasing the critical performance metrics of thrust, specific impulse and propulsive efficiency, the accelerators enable a number of new system features such as power tuning and thrust vectoring and balancing. Through microfabrication, we produced high density arrays (213 emitters cm−2) of capillary emitters, assembling them at wafer-level with an extractor/accelerator electrode pair separated by micro-sandblasted glass. Through IV measurements, we could confirm that acceleration could be decoupled from the extraction of the spray—an important element towards the flexibility of this technology. We present the largest reported internally fed microfabricated arrays operation, with 127 emitters spraying in parallel, for a total beam of 10–30 µA composed by 95% of ions. Effective beam focusing was also demonstrated, with plume half-angles being reduced from approximately 30° to 15° with 2000 V acceleration. Based on these results, we predict, with 3000 V acceleration, thrust per emitter of 38.4 nN, specific impulse of 1103 s and a propulsive efficiency of 22% with <1 mW/emitter power consumption. (paper)

  10. Measurement of alpha emitters in radioactive waste

    International Nuclear Information System (INIS)

    The alpha emitters measurement in radioactive waste (10-2Ci/T) is essential for a good fissil materials management. This paper describes 3 classes of devices: device using a neutronic passive counting, device using a neutronic activation and detection of fission gamma, device using a neutronic activation and detection of prompt neutrons fission

  11. THz imaging system with the IJJ emitter

    Science.gov (United States)

    Tsujimoto, Manabu; Minami, Hidetoshi; Sawamura, Masashi; Delfanazari, Kaveh; Yamamoto, Takashi; Kashiwagi, Takanari; Kadowaki, Kazuo

    2011-03-01

    The intrinsic Josephson junction (IJJ) emitter consisted of thousands of IJJs uniformly stacked in single crystalline high-Tc superconductor Bi 2 Sr 2 CaCu 2 O8 + δ (Bi-2212) [L. Ozyuzer et al., Science 318, (2007) 1291.] is expected to be a novel source of the continuous terahertz electromagnetic waves (THz-waves). The maximum emission power of tens of microwatts recently obtained with the mesa structure of IJJs seems to be sufficient to make use of the IJJ emitter for some practical applications such as THz imaging. According to the cavity resonance condition, we can control the radiation frequency by changing the geometrical size of the mesa. In this study, we develop the THz imaging system with IJJ emitter. In the presentation, we will show some transparent images of standard specimens obtained by the raster scanning method. Also, we will mention some problems to be solved for the future applications of the IJJ emitter. CREST-JST, WPI-MANA, Strategic Initiative A (University of Tsukuba).

  12. Optical beam diagnostics at the Electron Stretcher Accelerator ELSA

    International Nuclear Information System (INIS)

    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.

  13. Innovative Field Emitters for High-Voltage Electronic Devices

    Science.gov (United States)

    Sominski, G. G.; Sezonov, V. E.; Taradaev, E. P.; Tumareva, T. A.; Zadiranov, Yu. M.; Kornishin, S. Yu.; Stepanova, A. N.

    2015-12-01

    We describe multitip field emitters with protective coatings, which were developed in Peter the Great St. Petersburg Polytechnic University. The coatings ensure long-term operation of the emitters under high currents and technical vacuum. Innovative multi-layer emitters composed of contacting nanolayers of materials with different work functions are presented as well. The possibility by using the developed emitters in high-voltage electronic devices is demonstrated.

  14. What is so super about super-emitters? Characterizing methane high emitters from natural gas infrastructure

    Science.gov (United States)

    Zavala Araiza, D.; Lyon, D. R.; Alvarez, R.; Harriss, R. C.; Palacios, V.; Hamburg, S.

    2015-12-01

    Methane emissions across the natural gas supply chain are dominated at any one time by a few high-emitters (super-emitters or fat-tail of the distribution), often underrepresented in published datasets used to construct emission inventories. Characterization of high-emitters is essential for improving emission estimates based on atmospheric data (top-down) and emission inventories (bottom-up). The population of high-emitters (e.g. 10-20% of sites that account for 80-90% of the emissions) is temporally and spatially dynamic. As a consequence, it is challenging to design sampling methods and construct estimates that accurately represent their frequency and magnitude of emissions. We present new methods to derive facility-specific emission distribution functions that explicitly integrate the influence of the relatively rare super-emitters. These methods were applied in the Barnett Shale region to construct a custom emission inventory that is then compared to top-down emission estimates for the region. We offer a methodological framework relevant to the design of future sampling campaigns, in which these high-emitters are seamlessly incorporated to representative emissions distributions. This framework can be applied to heterogeneous oil and gas production regions across geographies to obtain accurate regional emission estimates. Additionally, we characterize emissions relative to the fraction of a facility's total methane throughput; an effective metric to identify sites with excess emissions resulting from avoidable operating conditions, such as malfunctioning equipment (defined here as functional super-emitters). This work suggests that identifying functional super-emitters and correcting their avoidable operating conditions would result in significant emission reductions. However, due to their spatiotemporal dynamic behavior, achieving and maintaining uniformly low emissions across the entire population of sites will require mitigation steps (e.g. leak detection

  15. RF Emitter geolocation using PDOA algorithms and UAVs - A strategy from emitter detection to location prediction

    OpenAIRE

    Engebråten, Sondre Andreas

    2015-01-01

    In this thesis, I explored strategies for locating an RF emitter. Expanding on an idea conceived at Norwegian Defence Research Establishment (FFI), of using small, cheap RSS sensors and Unmanned Aerial Vehicles (UAVs) to search for unknown RF emitters. Cheap and simple, will in most cases, mean that some property of the system suffers, compared to more complicated and expensive systems. This thesis attempts to circumvent these issues by using multiple sensors instead of one ...

  16. High-temperature plasmonic thermal emitter for thermophotovotaics

    DEFF Research Database (Denmark)

    Liu, Jingjing; Guler, Urcan; Li, Wei; Kildishev, Alexander V.; Boltasseva, Alexandra; Shalaev, Vladimir M.

    2014-01-01

    We use titanium nitride (TiN) to demonstrate an ultra-thin plasmonic thermal emitter operating at high temperatures (830 K). The spectrally selective emitter exhibits a large emittance at around 2.5 μm and below, and suppresses emission at longer wavelengths....

  17. Longitudinal emittance measurements in the Booster and AGS during the 2014 RHIC gold run

    Energy Technology Data Exchange (ETDEWEB)

    Zeno, K. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.

    2014-08-18

    This note describes longitudinal emittance measurements that were made in the Booster and AGS during the 2014 RHIC Gold run. It also contains an overview of the longitudinal aspects of their setup during this run. Each bunch intended for RHIC is composed of beam from 4 Booster cycles, and there are two of them per AGS cycle. For each of the 8 Booster cycles required to produce the 2 bunches in the AGS, a beam pulse from EVIS is injected into the Booster and captured in four h=4 buckets. Then those bunches are accelerated to a porch where they are merged into 2 bunches and then into 1 bunch.

  18. Longitudinal emittance measurements in the Booster and AGS during the 2014 RHIC gold run

    International Nuclear Information System (INIS)

    This note describes longitudinal emittance measurements that were made in the Booster and AGS during the 2014 RHIC Gold run. It also contains an overview of the longitudinal aspects of their setup during this run. Each bunch intended for RHIC is composed of beam from 4 Booster cycles, and there are two of them per AGS cycle. For each of the 8 Booster cycles required to produce the 2 bunches in the AGS, a beam pulse from EVIS is injected into the Booster and captured in four h=4 buckets. Then those bunches are accelerated to a porch where they are merged into 2 bunches and then into 1 bunch.

  19. NLC Luminosity as a Function of Beam Parameters

    CERN Document Server

    Nosochkov, Yu M; Raubenheimer, T O; Seryi, Andrei

    2002-01-01

    Realistic calculation of NLC luminosity has been performed using particle tracking in DIMAD and beam-beam simulations in GUINEA-PIG code for various values of beam emittance, energy and beta functions at the Interaction Point (IP). Results of the simulations are compared with analytic luminosity calculations. The optimum range of IP beta functions for high luminosity was identified.

  20. Beam extraction system in AIC-144 automatic isochronous cyclotron

    International Nuclear Information System (INIS)

    Project of beam extraction system in Cracow AIC-144 cyclotron is described. The problems of increase of beam emittance, and change of the magnetic field in the cyclotron chamber are discussed. Expected extraction coefficient of the beam is about 0.7. (S.B.)

  1. An ESQ lens system for low energy beam transport experiments on the SSC test stand

    International Nuclear Information System (INIS)

    A low-energy beam transport system is designed with the aim of transporting a 30 mA, 35 kV H- beam from a volume source and focusing it into an RFQ. The characteristics of the beam from the source are determined analyzing the emittance data. The behavior of the beam through the LEBT is studied using simulation codes. The system parameters are optimized so that the LEBT has a very modest contribution to the emittance growth (here a factor of about 1.5) and the emittance budget of the linac section is maintained

  2. Emittance measurement and optimization for the photocathode RF gun with laser profile shaping

    International Nuclear Information System (INIS)

    The Laser Undulator Compact X-ray source (LUCX) is a test bench for a compact high brightness X-ray generator, based on inverse Compton Scattering at KEK, which requires high intensity multi-bunch trains with low transverse emittance. A photocathode RF gun with emittance compensation solenoid is used as an electron source. Much endeavor has been made to increase the beam intensity in the multi-bunch trains. The cavity of the RF gun is tuned into an unbalanced field in order to reduce space charge effects, so that the field gradient on the cathode surface is relatively higher when the forward RF power into gun cavity is not high enough. A laser profile shaper is employed to convert the driving laser profile from Gaussian into uniform. In this research we seek to find the optimized operational conditions for the decrease of the transverse emittance. With the uniform driving laser and the unbalanced RF gun, the RMS transverse emittance of a 1 nC bunch has been improved effectively from 5.46 πmm.mrad to 3.66 πmm·mrad. (authors)

  3. Focusing performance and thermal property of carbon-nanotube emitter-based X-ray sources

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Seung Ho; Kim, Wan Sun; Ryu, Je Hwang; Kim, Kyung Sook; Park, Hun Kuk [Kyung Hee University, Seoul (Korea, Republic of)

    2014-12-15

    Carbon-nanotube (CNT) emitter-based X-ray sources have been extensively investigated as new imaging devices. The electron-beam trajectory in the CNT emitter-based X-ray sources were simulated to determine the optimized conditions for high focusing performance and limited thermal damage to the anode. The beam trajectory from the cathode to the anode was simulated, and the focal spot size (FSS) of the beam was determined by varying the structure of the electrode in the X-ray system. The temperature change of the anode caused by the electron-beam was calculated. The effects of electrode voltage and of the distance between the electrode and the anode on the FSS were significant while the effect of electrode thickness was small in all structures. When the electron-beam was emitted with an FSS of 170 μm and a power of 130 W, the thermal damage to the anode was reduced by using a 2-ms pulsed-voltage operation for a duration of 8 ms.

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

    International Nuclear Information System (INIS)

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

  5. Electron Beam Ion Sources

    CERN Document Server

    Zschornacka, G; Thorn, A

    2013-01-01

    Electron beam ion sources (EBISs) are ion sources that work based on the principle of electron impact ionization, allowing the production of very highly charged ions. The ions produced can be extracted as a DC ion beam as well as ion pulses of different time structures. In comparison to most of the other known ion sources, EBISs feature ion beams with very good beam emittances and a low energy spread. Furthermore, EBISs are excellent sources of photons (X-rays, ultraviolet, extreme ultraviolet, visible light) from highly charged ions. This chapter gives an overview of EBIS physics, the principle of operation, and the known technical solutions. Using examples, the performance of EBISs as well as their applications in various fields of basic research, technology and medicine are discussed.

  6. Small horizontal emittance in the TESLA damping ring

    International Nuclear Information System (INIS)

    The present TESLA damping ring is designed for a normalized horizontal emittance of 8x10-6 m. γ-γ collisions at the TESLA linear collider will benefit from a further decrease of the horizontal emittance. This paper reviews the processes which limit the horizontal emittance in the damping ring. Preliminary estimates on the smallest horizontal emittance for the present TESLA damping ring design as well as an ultimate limit of the emittance reachable with the TESLA damping ring concept will be given

  7. Studying fringe field effect of a field emitter array

    International Nuclear Information System (INIS)

    Field emitter arrays on heavy As-doped Si wafer are studied in vacuum nanoelectronics diode configuration. Different shapes of emitters are considered: cone-shaped point-emitters and cylinder-shaped sharp-edge-emitters are compared. Micro scale field enhancement factor on the edge of cylindrical emitter was calculated via home-developed Matlab application and the results are presented. Two types of anode geometry are proposed: plane anode and spherical anode. Experimental and modelling results of surface electric field distribution are presented. The spherical shape of anode allows higher voltage (and higher field emission current) without destructive arcs risk

  8. Emittance growth caused by electron cloud below the "fast-TMCI" threshold numerical noise or true physics?

    CERN Document Server

    Benedetto, Elena; Zimmermann, Frank; Franchetti, Giuliano; Ohmi, K

    2005-01-01

    Simulations show a persisting slow emittance growth for electron cloud densities below the threshold of the fast Transverse Mode Coupling type instability, which could prove important for proton beams with negligible radiation damping, such as in the LHC. We report on a variety of studies performed to quantify the contributions to the simulated emittance growth from numerical noise in the PIC module and from an artificial resonance excitation due to the finite number of kicks per turn applied for modeling the cloud-bunch interaction.

  9. X-ray Fresnel diffractometry for micron light source size measurement of ultralow-emittance next-generation storage ring

    International Nuclear Information System (INIS)

    A novel emittance diagnostics technique with high sensitivity using X-ray Fresnel diffraction by a single slit has been developed to measure micron-order electron beam sizes at insertion devices (IDs) of photon beamlines. The X-ray Fresnel diffractometry (XFD) is promising for diagnostics of next-generation light sources, where a tuning of ultra-low emittance at IDs is essentially important to ensure the absence of degradation of brilliance and transverse coherence of radiation at beamlines due to distortion of lattice functions. The validity of the new method was theoretically and experimentally studied at SPring-8. The achievable resolution of XFD is also discussed. (author)

  10. Analytical Approach to Eigen-Emittance Evolution in Storage Rings

    International Nuclear Information System (INIS)

    This dissertation develops the subject of beam evolution in storage rings with nearly uncoupled symplectic linear dynamics. Linear coupling and dissipative/diffusive processes are treated perturbatively. The beam distribution is assumed Gaussian and a function of the invariants. The development requires two pieces: the global invariants and the local stochastic processes which change the emittances, or averages of the invariants. A map based perturbation theory is described, providing explicit expressions for the invariants near each linear resonance, where small perturbations can have a large effect. Emittance evolution is determined by the damping and diffusion coefficients. The discussion is divided into the cases of uniform and non-uniform stochasticity, synchrotron radiation an example of the former and intrabeam scattering the latter. For the uniform case, the beam dynamics is captured by a global diffusion coefficient and damping decrement for each eigen-invariant. Explicit expressions for these quantities near coupling resonances are given. In many cases, they are simply related to the uncoupled values. Near a sum resonance, it is found that one of the damping decrements becomes negative, indicating an anti-damping instability. The formalism is applied to a number of examples, including synchrobetatron coupling caused by a crab cavity, a case of current interest where there is concern about operation near half integer νx. In the non-uniform case, the moment evolution is computed directly, which is illustrated through the example of intrabeam scattering. Our approach to intrabeam scattering damping and dicusion has the advantage of not requiring a loosely-defined Coulomb Logarithm. It is found that in some situations there is a small difference between our results and the standard approaches such as Bjorken-Mtingwa, which is illustrated by comparison of the two approaches and with a measurement of Au evolution in RHIC. Finally, in combining IBS with the

  11. Analytical Approach to Eigen-Emittance Evolution in Storage Rings

    Energy Technology Data Exchange (ETDEWEB)

    Nash, Boaz; /SLAC

    2006-05-16

    This dissertation develops the subject of beam evolution in storage rings with nearly uncoupled symplectic linear dynamics. Linear coupling and dissipative/diffusive processes are treated perturbatively. The beam distribution is assumed Gaussian and a function of the invariants. The development requires two pieces: the global invariants and the local stochastic processes which change the emittances, or averages of the invariants. A map based perturbation theory is described, providing explicit expressions for the invariants near each linear resonance, where small perturbations can have a large effect. Emittance evolution is determined by the damping and diffusion coefficients. The discussion is divided into the cases of uniform and non-uniform stochasticity, synchrotron radiation an example of the former and intrabeam scattering the latter. For the uniform case, the beam dynamics is captured by a global diffusion coefficient and damping decrement for each eigen-invariant. Explicit expressions for these quantities near coupling resonances are given. In many cases, they are simply related to the uncoupled values. Near a sum resonance, it is found that one of the damping decrements becomes negative, indicating an anti-damping instability. The formalism is applied to a number of examples, including synchrobetatron coupling caused by a crab cavity, a case of current interest where there is concern about operation near half integer {nu}{sub x}. In the non-uniform case, the moment evolution is computed directly, which is illustrated through the example of intrabeam scattering. Our approach to intrabeam scattering damping and diffusion has the advantage of not requiring a loosely-defined Coulomb Logarithm. It is found that in some situations there is a small difference between our results and the standard approaches such as Bjorken-Mtingwa, which is illustrated by comparison of the two approaches and with a measurement of Au evolution in RHIC. Finally, in combining IBS

  12. Cancellation of RF Coupler-Induced Emittance Due to Astigmatism

    CERN Document Server

    Dowell, David H

    2015-01-01

    It is well-known that the electron beam quality required for applications such as FELs and ultra-fast electron diffraction can be degraded by the asymmetric fields introduced by the RF couplers of superconducting linacs. This effect is especially troublesome in the injector where the low energy beam from the gun is captured into the first high gradient accelerator section. Unfortunately modifying the established cavity design is expensive and time consuming, especially considering that only one or two sections are needed for an injector. Instead, it is important to analyze the coupler fields to understand their characteristics and help find less costly solutions for their cancellation and mitigation. This paper finds the RF coupler-induced emittance for short bunches is mostly due to the transverse spatial sloping or tilt of the field, rather than the field's time-dependence. It is shown that the distorting effects of the coupler can be canceled with a static (DC) quadrupole lens rotated about the z-axis.

  13. Emittance-dominated long bunches in dual harmonic RF system

    Institute of Scientific and Technical Information of China (English)

    AN Shi-Zhong; Klaus Bongardt; Rudolf Maier; TANG Jing-Yu; ZHANG Tian-Jue

    2008-01-01

    The storage of long bunches for long time intervals needs flattened stationary buckets with a large bucket height. The longitudinal motion of the initially mismatched beam has been studied for both the single and dual harmonic RF systems. The RF amplitude is determined to be r.m.s wise matched. The bucket height of the single harmonic system is too small even for shorter bunch with only 20% increased energy spread. The Halo formation and even debunching can be seen after a few synchrotron periods for single particles with large amplitude. In the case of small energy spread for a cooled beam, Coulomb interaction cannot be ignored. The external voltage has to be increased to keep the r.m.s bunch length unchanged. The new voltage ratio R(N) simplifies physics for the emittance-dominated bunches with modest particle number N. For the single harmonic system, substantial amount of debunching occurs without increasing the external voltage, but very little if the RF amplitude is doubled. Results from the ORBIT tracking code are presented for the 1 GeV bunch in the HESR synchrotron, part of the GSI FAIR project.

  14. The influence of emitter conditioning on the performance of a tungsten <111> cold field emission gun operating at 300 kV

    International Nuclear Information System (INIS)

    In this contribution, we examine the influence of emitter conditioning for a <111> tungsten cold field emission gun on the emission and beam characteristics of a double aberration corrected electron microscope. By varying the post flash build-up parameters we can control the effective emitter tip radius. A sharp emitter yields an energy resolution of 0.31eV but relatively low beam current whereas an increased tip radius results in a reduction in energy resolution to 0.4eV but much higher potential beam current. Consequently, careful control of the build-up parameters can be used as a means of tailoring the emission to suit specific instrumental requirements

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2008-10-01

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

  16. Characterization of electron bunches from field emitter array cathodes for use in next-generation x-ray free electron lasers

    International Nuclear Information System (INIS)

    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)

  17. Suppression of Space Charge Induced Beam Halo in Nonlinear Focusing Channel

    CERN Document Server

    Batygin, Yuri K; Kurennoy, Sergey; Li, Chao

    2016-01-01

    An intense non-uniform particle beam exhibits strong emittance growth and halo formation in focusing channels due to nonlinear space charge forces of the beam. This phenomenon limits beam brightness and results in particle losses. The problem is connected with irreversible distortion of phase space volume of the beam in conventional focusing structures due to filamentation in phase space. Emittance growth is accompanied by halo formation in real space, which results in inevitable particle losses. A new approach for solving a self-consistent problem for a matched non-uniform beam in two-dimensional geometry is discussed. The resulting solution is applied to the problem of beam transport, while avoiding emittance growth and halo formation by the use of nonlinear focusing field. Conservation of a beam distribution function is demonstrated analytically and by particle-in-cell simulation for a beam with a realistic beam distribution.

  18. Suppression of space charge induced beam halo in nonlinear focusing channel

    Science.gov (United States)

    Batygin, Yuri K.; Scheinker, Alexander; Kurennoy, Sergey; Li, Chao

    2016-04-01

    An intense non-uniform particle beam exhibits strong emittance growth and halo formation in focusing channels due to nonlinear space charge forces of the beam. This phenomenon limits beam brightness and results in particle losses. The problem is connected with irreversible distortion of phase space volume of the beam in conventional focusing structures due to filamentation in phase space. Emittance growth is accompanied by halo formation in real space, which results in inevitable particle losses. A new approach for solving a self-consistent problem for a matched non-uniform beam in two-dimensional geometry is discussed. The resulting solution is applied to the problem of beam transport, while avoiding emittance growth and halo formation by the use of nonlinear focusing field. Conservation of a beam distribution function is demonstrated analytically and by particle-in-cell simulation for a beam with a realistic beam distribution.

  19. Emittance problems in Tau-charm factories

    International Nuclear Information System (INIS)

    Tau-charm factory (TCF) was proposed by J. Kirkby for high precision studies of τ-leptons, τ-neutrinos and charmed particles. A number of requirements for TCF physics put hard constraints on the machine. The peak luminosity must be around the τ-lepton production threshold energy of E≅2 GeV and higher than 1033 cm-2s-1. TCF must provide a high average luminosity and high luminosity must be provided is a wide energy range from E≅1.5∼2.85 GeV. In this report, the TCF lattice requirements and possible solutions were discussed. The lattices with FODO regular cells were considered to be suitable for TCF, although larger longitudinal acceptance at low emittance option is desirable. Additional studies for high emittance option with DBA and TBA regular cells are necessary to overcome small dynamic aperture. The main collider parameters of conventional and monochromatic designs were presented. And it was concluded that TCF should be designed with possibility to work not only with marginal values of emittance, but intermediate too. (M.N.)

  20. Single-Particle Dynamics in Electron Storage Rings with Extremely Low Emittance

    Energy Technology Data Exchange (ETDEWEB)

    Cai, Yunhai; /SLAC

    2011-05-31

    Electron storage rings are widely used for high luminosity colliders, damping rings in high-energy linear colliders, and synchrotron light sources. They have become essential facilities to study high-energy physics and material and medical sciences. To further increase the luminosity of colliders or the brightness of synchrotron light sources, the beam emittance is being continually pushed downward, recently to the nanometer region. In the next decade, another order of reduction is expected. This requirement of ultra-low emittance presents many design challenges in beam dynamics, including better analysis of maps and improvement of dynamic apertures. To meet these challenges, we have refined transfer maps of common elements in storage rings and developed a new method to compute the resonance driving terms as they are built up along a beamline. The method is successfully applied to a design of PEP-X as a future light source with 100-pm emittance. As a result, we discovered many unexpected cancelations of the fourth-order resonance terms driven by sextupoles within an achromat.

  1. Emissivity Tuned Emitter for RTPV Power Sources

    Energy Technology Data Exchange (ETDEWEB)

    Carl M. Stoots; Robert C. O' Brien; Troy M. Howe

    2012-03-01

    Every mission launched by NASA to the outer planets has produced unexpected results. The Voyager I and II, Galileo, and Cassini missions produced images and collected scientific data that totally revolutionized our understanding of the solar system and the formation of the planetary systems. These missions were enabled by the use of nuclear power. Because of the distances from the Sun, electrical power was produced using the radioactive decay of a plutonium isotope. Radioisotopic Thermoelectric Generators (RTGs) used in the past and currently used Multi-Mission RTGs (MMRTGs) provide power for space missions. Unfortunately, RTGs rely on thermocouples to convert heat to electricity and are inherently inefficient ({approx} 3-7% thermal to electric efficiency). A Radioisotope Thermal Photovoltaic (RTPV) power source has the potential to reduce the specific mass of the onboard power supply by increasing the efficiency of thermal to electric conversion. In an RTPV, a radioisotope heats an emitter, which emits light to a photovoltaic (PV) cell, which converts the light into electricity. Developing an emitter tuned to the desired wavelength of the photovoltaic is a key part in increasing overall performance. Researchers at the NASA Glenn Research Center (GRC) have built a Thermal Photovoltaic (TPV) system, that utilizes a simulated General Purpose Heat Source (GPHS) from a MMRTG to heat a tantalum emitter. The GPHS is a block of graphite roughly 10 cm by 10 cm by 5 cm. A fully loaded GPHS produces 250 w of thermal power and weighs 1.6 kgs. The GRC system relies on the GPHS unit radiating at 1200 K to a tantalum emitter that, in turn, radiates light to a GaInAs photo-voltaic cell. The GRC claims system efficiency of conversion of 15%. The specific mass is around 167 kg/kWe. A RTPV power source that utilized a ceramic or ceramic-metal (cermet) matrix would allow for the combination of the heat source, canister, and emitter into one compact unit, and allow variation in size

  2. Transverse Beam Matching Application for SNS

    CERN Document Server

    Chu, Chungming; Jeon Dong Oh; Plum, Michael

    2005-01-01

    An automated transverse beam matching application has been developed for the Spallation Neutron Source (SNS) beam transport lines. The application is written within the XAL Java framework and the matching algorithm is based on the simplex optimization method. Other functionalities, such as emittance calculated from profile monitor measurements (adopted from a LANL Fortran code), profile monitor display, and XAL on-line model calculation, are also provided by the application. Test results obtained during the SNS warm linac commissioning will be reported. A comparison between the emittances obtained from this application and an independent Trace-3D routine will also be shown.

  3. Requirements of CLIC Beam Loss Monitoring System

    CERN Document Server

    Sapinski, M; Holzer, EB; Jonker, M; Mallows, S; Otto, T; Welsch, C

    2010-01-01

    The Compact Linear Collider (CLIC) [1] is a proposed multi-TeV linear electron-positron collider being designed by a world-wide collaboration. It is based on a novel twobeam acceleration scheme in which two beams (drive and main beam) are placed in parallel to each other and energy is transferred from the drive beam to the main one. Beam losses on either of them can have catastrophic consequences for the machine, because of high intensity (drive beam) or high energy and small emittance (main beam). In the framework of machine protection, a Beam Loss Monitoring (BLM) system has to be put in place. This paper discusses the requirements for the beam loss system in terms of detector sensitivity, resolution, dynamic range and ability to distinguish losses originating from various sources. The two-beam module where the protection from beam losses is particularly challenging and important, is studied.

  4. Scheme to funnel ion beams with a radio-frequency quadrupole

    International Nuclear Information System (INIS)

    We describe a proposed method to funnel ion beams using a new form of the radio-frequency quadrupole (RFQ) structure. This RFQ accepts two bunched ion beams and combines them into a single final beam with interlaced microstructure pulses. It also provides uninterrupted periodic transverse focusing to facilitate the funneling of beams with high current and low emittance

  5. A fluor and wire-shadow diagnostic for low-energy ion beams

    International Nuclear Information System (INIS)

    A video diagnostic technique utilizing a fluorescent screen and a video camera has been developed to monitor the two-dimensional beam-intensity profile and angular divergence of low-energy (25-35 keV) ion beams. Detailed off-line analysis is used to compare and augment standard beam emittance data. Experimental results on 2-D beam profiles are presented

  6. Effect of Beamstrahlung on Bunch Length and Emittance in Future Circular e+e- Colliders

    CERN Document Server

    Valdivia Garcia, Marco Alan

    2016-01-01

    In future circular e+e− colliders, beamstrahlung may limit the beam lifetime at high energies, and increase the energy spread and bunch length at low energies. If the dispersion or slope of the dispersion is not zero at the collision point, beamstrahlung will also affect the transverse emittance. In this paper, we first examine the beamstrahlung properties, and show that for the proposed FCC-ee, the radiation is fairly well modelled by the classical formulae describing synchrotron radiation in bending magnets. We then derive a set of equations determining the equilibrium emittances in the presence of a nonzero dispersion at the collision point. An example case from FCC-ee will serve as an illustration.

  7. Effects of surface and volume production on emittance in a volume type negative ion source

    International Nuclear Information System (INIS)

    A volume-type negative ion source has been modeled using a version of the Negative Ion Injector Design Analysis Program (NIIDeAP). The purpose of the study was to investigate the relative effects of surface-produced ions and volume-produced ions on the emittance of the total extracted beam. The differences between the two types of ion production can be expected to influence energy and emittance distributions for several reasons. Even though the fundamental physics of ion production in the source imply a low temperature, the effects of magnetic field, internal surface geometry, plasma potential, and superposition of two different populations can result in a significant increase of the apparent temperature. A high precision ion trajectory integrator was used. (Author) 5 figs., 5 refs

  8. Fast electrical switching of orbital angular momentum modes using ultra-compact integrated vortex emitters.

    Science.gov (United States)

    Strain, Michael J; Cai, Xinlun; Wang, Jianwei; Zhu, Jiangbo; Phillips, David B; Chen, Lifeng; Lopez-Garcia, Martin; O'Brien, Jeremy L; Thompson, Mark G; Sorel, Marc; Yu, Siyuan

    2014-01-01

    The ability to rapidly switch between orbital angular momentum modes of light has important implications for future classical and quantum systems. In general, orbital angular momentum beams are generated using free-space bulk optical components where the fastest reconfiguration of such systems is around a millisecond using spatial light modulators. In this work, an extremely compact optical vortex emitter is demonstrated with the ability to actively tune between different orbital angular momentum modes. The emitter is tuned using a single electrically contacted thermo-optical control, maintaining device simplicity and micron scale footprint. On-off keying and orbital angular momentum mode switching are achieved at rates of 10 μs and 20 μs respectively. PMID:25229882

  9. Building a backlight unit with lateral gate structure based on carbon nanotube field emitters

    International Nuclear Information System (INIS)

    This paper describes the fabrication of a backlight unit for liquid crystal display based on printed carbon nanotube field emitters with lateral gate and additional mesh structures. The device architecture has been optimized through field emission characterization and supporting numerical simulation. The emission current depends strongly on the cathode-gate gap, mesh position, and mesh bias. Direct observation of luminous images on a phosphor screen reveals that the electron beams undergo a noticeable shrinkage along the lateral direction with increasing anode bias, which is in good agreement with the simulation results. We suggest and demonstrate a modified structure equipped with double emitter edges leading to ∼20% improved phosphor efficiency (34.4 lm W-1) and luminance (9600 cd m-2), compared to those from a single edge structure.

  10. Inducing electron emission from field emitter arrays by fs near infrared laser pulses

    International Nuclear Information System (INIS)

    Full text: Field-emitter array (FEA) cathode generates electron beam by electron tunneling under intense electric field. Although FEA are capable of delivering very high current-density, production of short electron bunches with the duration of picosecond or below by electrical switching is challenging limiting their application. In this work, we trigger field emission from ultrasharp tip arrays by 50 fs near infrared laser pulses. Despite small total emission area of FEAs, generation of up 107 electron per laser pulse was observed. Laser-intensity dependence indicated photo-field emission from FEAs as the electron emission process. Electromagnetic simulations demonstrated that sharp tips can enhance emission yields through shape-induced local field enhancement. The observed high charge generation indicates the feasibility of using field-emitter array cathode for applications in THz vacuum electronic as well as accelerator applications like SwissFEL X-ray free electron laser. (author)

  11. Polyaniline: a conductive polymer coating for durable nanospray emitters

    Science.gov (United States)

    Maziarz; Lorenz; White; Wood

    2000-07-01

    Despite the tremendous sensitivity and lower sample requirements for nanospray vs. conventional electrospray, metallized nanospray emitters have suffered from one of two problems: low mechanical stability (leading to emitter failure) or lengthy, tedious production methods. Here, we describe a simple alternative to metallized tips using polyaniline (PANI), a synthetic polymer well known for its high conductivity, anticorrosion properties, antistatic properties, and mechanical stability. A simple method for coating borosilicate emitters (1.2 mm o.d.) pulled to fine tapers (4 +/- 1 microm) with water-soluble and xylene-soluble dispersions of conductive polyaniline (which allows for electrical contact at the emitter outlet) is described. The polyaniline-coated emitters show high durability and are resistant to electrical discharge, likely because of the thick (yet optically transparent) coatings; a single emitter can be used over a period of days for multiple samples with no visible indication of the destruction of the polyaniline coating. The optical transparency of the coating also allows the user to visualize the sample plug loaded into the emitter. Examples of nanospray using coatings of the water-soluble and xylene-soluble polyaniline dispersions are given. A comparison of PANI-coated and gold-coated nanospray emitters to conventional electrospray ionization (ESI) show that PANI-coated emitters provide similar enhanced sensitivity that gold-coated emitters exhibit vs. conventional ESI. PMID:10883822

  12. Simulation studies for ion beam extraction systems

    Energy Technology Data Exchange (ETDEWEB)

    Abdelrahman, M.M.; Zakhary, S.G. [Atomic Energy, Cairo (Egypt). Nuclear Research Center. Accelerators and Ion Sources Dept.], e-mail: moustafa82003@yahoo.com

    2009-06-15

    The characteristics of the ion beam extracted from an ion sources were investigated using computer code SIMION 3 D Version 7.0. It has been used to evaluate the extraction system in order to produce an ion beam with high current and low beam emittance. The results show that the shape of the extraction electrode plays an important role in ion beam formation. Comparison has been made between two extraction systems, Pierce extraction electrode and spherical extraction electrode. The results show that the spherical extraction system yields ion extraction beam with lower emittance and radius than that the Pierce system. The simulation can provide the basis for optimizing the extraction system and the acceleration gap for ion source. (author)

  13. Beam dynamics with new booster dipoles

    International Nuclear Information System (INIS)

    New bending magnets are being designed for the booster synchrotron at RRCAT, Indore with the same effective length and field which will be installed in the existing ring with the same configuration of drifts and quadrupole magnets. Presently sector type dipoles are in use. It is easier to fabricate parallel edge (rectangular type) dipoles but the beam optics gets modified due to edges which provide additional focusing. The effect on tune point can be corrected using two quadrupole families. Studies indicate that the beam emittance is lower in the optics with rectangular type dipoles but the beam injection and extraction are more difficult. In this paper, the beam optics, beam emittance, injection and extraction with two configurations of the dipole magnets are compared. (author)

  14. The Physics and Applications of High Brightness Beams: Working Group A Summary on High Brightness Beam Production

    International Nuclear Information System (INIS)

    Working group A was devoted to high brightness beam production and characterization. The presentations and discussions could be categorized as cathode physics, new photoinjector designs, computational modeling of high brightness beams, and new experimental methods and results. Several novel injector and cathode designs were presented. However, a standard 1.5 cell rf photoinjector is still the most common source for high brightness beams. New experimental results and techniques were presented and thoroughly discussed. The brightest beam produced in a rf photoinjector published at the time of the workshop is approximately 2 1014 A/(m-rad)2 at Sumitomo Heavy Industries in Japan with 1 nC of charge, a 9 ps FWHM long laser pulse and a normalized transverse emittance of 1.2 pm. The emittance was achieved by utilizing a temporally flat laser pulse which decreased the emittance by an estimated factor of 2 from the beam produced with a Gaussian pulse shape with an identical pulse length

  15. 100 W/100 μm passively cooled fiber coupled diode laser at 976 nm based on multiple 100 μm single emitters

    Science.gov (United States)

    Werner, Marcel; Wessling, Christian; Hengesbach, Stefan; Traub, Martin; Hoffmann, Hans-Dieter

    2009-02-01

    We developed a high brightness fiber coupled diode laser module based on single diode lasers providing more than 60 Watts output power from a 100 micron fiber at the optimum fiber laser pump wavelength of 976 nm. The advantage of using multiple single emitters on a submount compared to using bars or mini bars is the direct fiber coupling by use of optical stacking and the fact that no beam transformation is needed. We achieved best brightness with a high fill factor, optical efficiency of more then 80% and wall-plug efficiency of more then 40%. The use of single emitters on a submount also extends the life span due to reduced failure (xn vs. x) per device (n individual emitters vs. n emitters on a bar (mini array)). Low drive current enables modulation.

  16. Infrared spectral normal emittance/emissivity comparison

    Science.gov (United States)

    Hanssen, L.; Wilthan, B.; Filtz, J.-R.; Hameury, J.; Girard, F.; Battuello, M.; Ishii, J.; Hollandt, J.; Monte, C.

    2016-01-01

    The National Measurement Institutes (NMIs) of the United States, Germany, France, Italy and Japan, have joined in an inter-laboratory comparison of their infrared spectral emittance scales. This action is part of a series of supplementary inter-laboratory comparisons (including thermal conductivity and thermal diffusivity) sponsored by the Consultative Committee on Thermometry (CCT) Task Group on Thermophysical Quantities (TG-ThQ). The objective of this collaborative work is to strengthen the major operative National Measurement Institutes' infrared spectral emittance scales and consequently the consistency of radiative properties measurements carried out worldwide. The comparison has been performed over a spectral range of 2 μm to 14 μm, and a temperature range from 23 °C to 800 °C. Artefacts included in the comparison are potential standards: oxidized Inconel, boron nitride, and silicon carbide. The measurement instrumentation and techniques used for emittance scales are unique for each NMI, including the temperature ranges covered as well as the artefact sizes required. For example, all three common types of spectral instruments are represented: dispersive grating monochromator, Fourier transform and filter-based spectrometers. More than 2000 data points (combinations of material, wavelength and temperature) were compared. Ninety-eight percent (98%) of the data points were in agreement, with differences to weighted mean values less than the expanded uncertainties calculated from the individual NMI uncertainties and uncertainties related to the comparison process. Main text To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCT, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

  17. Micro computer aided beam transport for the SF cyclotron

    International Nuclear Information System (INIS)

    An improvement of the beam transport system for the SF cyclotron is described. The system was designed to handle on-line alignment of the beam extracted from the SF cyclotron onto the optical axis of the transport line. It also enables to measure the beam emittance. The measurement of the emittance parameters is in particular necessary to calculate the beam optics. The calculation has been modified to become easy to handle. With the help of the computer-aided on-line beam profile measurement system, the operation of the beam transport system is very subservient to shorten the beam-tuning time and to improve the beam-transmission efficiency and the quality. (author)

  18. The Saturne beam measurement system for orbit corrections and high and low intensity beam acceleration

    International Nuclear Information System (INIS)

    This paper summarizes the dipolar and multipolar correction system and the main beam diagnostics of Saturne II: wide-band RF electrostatic pick-up electrode for observation of bunches, beam position and tune measurement systems, special electrodes for observation of emittance blow-up when particles cross a resonance line. For low intensity beams, special electrodes and electronics have been developed. All this instrumentation is computer controlled

  19. Quadrupole modes in linearized beam-beam interaction in e+e- colliding rings

    International Nuclear Information System (INIS)

    The dynamic-beta model is extended, incorporating the synchrotron radiation effects. The model yields dynamic-emittance effect. The steady-state envelope matrix is explicitly obtained. Both equal-beam and flip-flop solutions are found. The stability of the steady-state solutions are investigated by numerical calculations. The model illustrates some characteristic features of the beam-beam interaction at e+e- colliding rings in spite of containing some qualitatively unrealistic points. (author)

  20. Emittance growth from transient coherent synchrotron radiation

    International Nuclear Information System (INIS)

    If the energies of individual particles in a bunch change as the bunch traverses a bending system, even if it is achromatic, betatron oscillations can be excited. Consequently, the transverse emittance of the bunch will grow as it moves downstream. Short bunches may be particularly susceptible to emission of coherent synchrotron radiation which can act back on the particles to change their energies and trajectories. Because a bend spans a well-defined length and angle, the bunch-excited wakefield and its effect back on the bunch are inherently transient. We outline a recently developed theory of this effect and apply it to example bending systems

  1. Thermal emittance measurements of a cesium potassium antimonide photocathode

    OpenAIRE

    Bazarov, Ivan; Cultrera, Luca; Bartnik, Adam; Dunham, Bruce; Karkare, Siddharth; Li, Yulin; Liu, Xianghong; Maxson, Jared; Roussel, William

    2011-01-01

    Thermal emittance measurements of a CsK2Sb photocathode at several laser wavelengths are presented. The emittance is obtained with a solenoid scan technique using a high voltage dc photoemission gun. The thermal emittance is 0.56+/-0.03 mm-mrad/mm(rms) at 532 nm wavelength. The results are compared with a simple photoemission model and found to be in a good agreement.

  2. Thermal emittance measurements of a cesium potassium antimonide photocathode

    Science.gov (United States)

    Bazarov, Ivan; Cultrera, Luca; Bartnik, Adam; Dunham, Bruce; Karkare, Siddharth; Li, Yulin; Liu, Xianghong; Maxson, Jared; Roussel, William

    2011-05-01

    Thermal emittance measurements of a CsK2Sb photocathode at several laser wavelengths are presented. The emittance is obtained with a solenoid scan technique using a high voltage dc photoemission gun. The thermal emittance is 0.56±0.03 mm mrad/mm(rms) at 532 nm wavelength. The results are compared with a simple photoemission model and found to be in a good agreement.

  3. Off-line emittance measurements of the SPES ion source at LNL

    International Nuclear Information System (INIS)

    In the framework of the SPES Radioactive Beam Facility of INFN, a dedicated Ion Source R and D program has recently been started at the Legnaro Laboratory. The main goal is to study and improve its quality. The measurements of transverse phase space distributions of the ions produced in the target complex are of great importance for every ISOL based facility like for example SPES. In particular the phase space distribution becomes essential for the determination of simulation parameters and hence for the mass separation, the injection into traps and breeders, calculation of transport losses, etc. For these reasons a new beam emittance analyzer device, developed at the Legnaro laboratories, has recently been coupled with an off-line target front-end. The experimental measurements on the SPES surface ion source, using three different stable ion beams (Rb, Cs, Al), and their analysis, are presented here.

  4. Statistics of scattered photons from a driven three-level emitter in 1D open space

    Energy Technology Data Exchange (ETDEWEB)

    Roy, Dibyendu [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Div. and Center for Nonlinear Studies; Bondyopadhaya, Nilanjan [Visva-Bharati University, Santiniketan (India). Integrated Science Education and Research Centre

    2014-01-07

    We derive the statistics of scattered photons from a Λ- or ladder-type three-level emitter (3LE) embedded in a 1D open waveguide. The weak probe photons in the waveguide are coupled to one of the two allowed transitions of the 3LE, and the other transition is driven by a control beam. This system shows electromagnetically induced transparency (EIT) which is accompanied with the Autler-Townes splitting (ATS) at a strong driving by the control beam, and some of these effects have been observed recently. We show that the nature of second-order coherence of the transmitted probe photons near two-photon resonance changes from bunching to antibunching to constant as strength of the control beam is ramped up from zero to a higher value where the ATS appears.

  5. Fibrous selective emitter structures from sol-gel process

    International Nuclear Information System (INIS)

    Selective emitters have the potential benefit of high efficiency due to the matching of emission spectra to the response of photovoltaic (PV) cells. Continuous uniform rare-earth oxide selective emitter fibers were successfully fabricated using a viscous solution made from metal organic precursors. Cylindrical- and planar configuration emitter structures were made by direct cross-winding or stacking of precursor fiber layers. The combustion and optical performance of the planar emitter structures were tested. The results indicates that both the designing of the fiber packing density and the thickness is critical for high photon and power output

  6. Intelligent Variable Emittance Panels Using New, ""True"" Solid Electrolyte Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This work further developed a highly promising Variable Emittance technology for spacecraft thermal control based on Conducting Polymer (CP) electrochromics...

  7. Low energy ion beam dynamics of NANOGAN ECR ion source

    Science.gov (United States)

    Kumar, Sarvesh; Mandal, A.

    2016-04-01

    A new low energy ion beam facility (LEIBF) has been developed for providing the mass analyzed highly charged intense ion beams of energy ranging from a few tens of keV to a few MeV for atomic, molecular and materials sciences research. The new facility consists of an all permanent magnet 10 GHz electron cyclotron resonance (ECR) ion source (NANOGAN) installed on a high voltage platform (400 kV) which provides large currents of multiply charged ion beams. Higher emittance at low energy of intense ion beam puts a tremendous challenge to the beam optical design of this facility. The beam line consists of mainly the electrostatic quadrupoles, an accelerating section, analyzing cum switching magnet and suitable beam diagnostics including vacuum components. The accelerated ion beam is analyzed for a particular mass to charge (m/q) ratio as well as guided to three different lines along 75°, 90° and 105° using a large acceptance analyzing cum switching magnet. The details of transverse beam optics to all the beam lines with TRANSPORT and GICOSY beam optics codes are being described. Field computation code, OPERA 3D has been utilized to design the magnets and electrostatic quadrupoles. A theoretical estimation of emittance for optimized geometry of ion source is given so as to form the basis of beam optics calculations. The method of quadrupole scan of the beam is used to characterize the emittance of the final beam on the target. The measured beam emittance increases with m/q ratios of various ion beams similar to the trend observed theoretically.

  8. High intensity ion beam injection into the 88-inch cyclotron

    OpenAIRE

    Wutte, Daniela; Clark, Dave J.; Laune, Bernard; Leitner, Matthaeus A.; Lyneis, Claude M.

    2000-01-01

    Low cross section experiments to produce super-heavy elements have increased the demand for high intensity heavy ion beams at energies of about 5 MeV/nucleon at the 88-Inch Cyclotron at the Lawrence Berkeley National Laboratory. Therefore, efforts are underway to increase the overall ion beam transmission through the axial injection line and the cyclotron. The ion beam emittance has been measured for various ion masses and charge states. Beam transport simulations including space charge ...

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

    International Nuclear Information System (INIS)

    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

  10. Optics and beam guidance

    International Nuclear Information System (INIS)

    This is an introductory manual for the field of particle transport (guiding). The utilized method described is that of classical geometrical optics which is based on the action principle or minimal action principle. This manual is addressed to readers neither specialized or familiar with intricate computations. The treatment is focussed upon the transport line of an experimental beam conceived for the late-project PIAFE. This case was chosen as it poses and solves certain significant difficult issues. In addition it will also allow in course of exposition to illustrate formulas and properties and also to give orders of magnitude. Background notions are given on: forces, curvature radius, potential, energy and units. The frame of conception is defined by means of the concepts of particle, referential trajectory, emittance, quadrupoles, electrostatic lenses, etc. Simulation for a large number of systems can be done with fairly high accuracy with the aid of thin lenses. Consequently the properties of several assemblies as for instance the periodic system 'FODO' are studied on the case of a single particle and emittance by means of adaptation and stability notions. The manual is structured on the following sections: 1. Introduction; 2. Basic notions; 3. Particle trajectories; 4. The real beam. Emittance and Evolution; 5.Optics notions and applications; 6. Elements of focusing; 7. Particle beam bending; 8. Some items presented in annexes and conclusions. In annexes the following important technical issues are addressed: 1. Effects of alignment failures on PIAFE structure trajectories; 2. Alignment. Phase 1: Magnetic centers and quadrupoles; 3. Alignment. Phase 2: Structures; 4. Residual gas/ Required pressure

  11. Barium depletion in hollow cathode emitters

    International Nuclear Information System (INIS)

    Dispenser hollow cathodes rely on a consumable supply of Ba released by BaO-CaO-Al2O3 source material in the pores of a tungsten matrix to maintain a low work function surface. The examination of cathode emitters from long duration tests shows deposits of tungsten at the downstream end that appear to block the flow of Ba from the interior. In addition, a numerical model of Ba transport in the cathode plasma indicates that the Ba partial pressure in the insert may exceed the equilibrium vapor pressure of the dominant Ba-producing reaction, and it was postulated previously that this would suppress Ba loss in the upstream part of the emitter. New measurements of the Ba depletion depth from a cathode insert operated for 8200 h reveal that Ba loss is confined to a narrow region near the downstream end, confirming this hypothesis. The Ba transport model was modified to predict the depletion depth with time. A comparison of the calculated and measured depletion depths gives excellent qualitative agreement, and quantitative agreement was obtained assuming an insert temperature 70 °C lower than measured beginning-of-life values

  12. Barium depletion in hollow cathode emitters

    Energy Technology Data Exchange (ETDEWEB)

    Polk, James E., E-mail: james.e.polk@jpl.nasa.gov; Mikellides, Ioannis G.; Katz, Ira [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California 91109 (United States); Capece, Angela M. [Graduate Aerospace Laboratories, California Institute of Technology, Pasadena, California 91125 (United States)

    2016-01-14

    Dispenser hollow cathodes rely on a consumable supply of Ba released by BaO-CaO-Al{sub 2}O{sub 3} source material in the pores of a tungsten matrix to maintain a low work function surface. The examination of cathode emitters from long duration tests shows deposits of tungsten at the downstream end that appear to block the flow of Ba from the interior. In addition, a numerical model of Ba transport in the cathode plasma indicates that the Ba partial pressure in the insert may exceed the equilibrium vapor pressure of the dominant Ba-producing reaction, and it was postulated previously that this would suppress Ba loss in the upstream part of the emitter. New measurements of the Ba depletion depth from a cathode insert operated for 8200 h reveal that Ba loss is confined to a narrow region near the downstream end, confirming this hypothesis. The Ba transport model was modified to predict the depletion depth with time. A comparison of the calculated and measured depletion depths gives excellent qualitative agreement, and quantitative agreement was obtained assuming an insert temperature 70 °C lower than measured beginning-of-life values.

  13. Barium depletion in hollow cathode emitters

    Science.gov (United States)

    Polk, James E.; Mikellides, Ioannis G.; Capece, Angela M.; Katz, Ira

    2016-01-01

    Dispenser hollow cathodes rely on a consumable supply of Ba released by BaO-CaO-Al2O3 source material in the pores of a tungsten matrix to maintain a low work function surface. The examination of cathode emitters from long duration tests shows deposits of tungsten at the downstream end that appear to block the flow of Ba from the interior. In addition, a numerical model of Ba transport in the cathode plasma indicates that the Ba partial pressure in the insert may exceed the equilibrium vapor pressure of the dominant Ba-producing reaction, and it was postulated previously that this would suppress Ba loss in the upstream part of the emitter. New measurements of the Ba depletion depth from a cathode insert operated for 8200 h reveal that Ba loss is confined to a narrow region near the downstream end, confirming this hypothesis. The Ba transport model was modified to predict the depletion depth with time. A comparison of the calculated and measured depletion depths gives excellent qualitative agreement, and quantitative agreement was obtained assuming an insert temperature 70 °C lower than measured beginning-of-life values.

  14. Beam Conditioning for FELs: Consequences and Methods

    Energy Technology Data Exchange (ETDEWEB)

    Wolski, Andrzej; Penn, Gregory; Sessler, Andrew; Wurtele, Jonathan

    2003-10-09

    The consequences of beam conditioning in four example cases (VISA, a Soft X-Ray FEL, LCLS and a ''Greenfield'' FEL) are examined. It is shown that in emittance limited cases, proper conditioning reduces sensitivity to the transverse emittance, and allows stronger focusing in the undulator. Simulations show higher saturation power, with gain lengths reduced up to a factor of two. The beam dynamics in a general conditioning system are studied, with ''matching conditions'' derived for achieving conditioning without growth in effective emittance. Various conditioners are considered, and expressions derived for the amount of conditioning provided in each case when the matching conditions are satisfied. We discuss the prospects for conditioners based on laser and plasma systems.

  15. Compact Rare Earth Emitter Hollow Cathode

    Science.gov (United States)

    Watkins, Ronald; Goebel, Dan; Hofer, Richard

    2010-01-01

    A compact, high-current, hollow cathode utilizing a lanthanum hexaboride (LaB6) thermionic electron emitter has been developed for use with high-power Hall thrusters and ion thrusters. LaB6 cathodes are being investigated due to their long life, high current capabilities, and less stringent xenon purity and handling requirements compared to conventional barium oxide (BaO) dispenser cathodes. The new cathode features a much smaller diameter than previously developed versions that permit it to be mounted on axis of a Hall thruster ( internally mounted ), as opposed to the conventional side-mount position external to the outer magnetic circuit ("externally mounted"). The cathode has also been reconfigured to be capable of surviving vibrational loads during launch and is designed to solve the significant heater and materials compatibility problems associated with the use of this emitter material. This has been accomplished in a compact design with the capability of high-emission current (10 to 60 A). The compact, high-current design has a keeper diameter that allows the cathode to be mounted on the centerline of a 6- kW Hall thruster, inside the iron core of the inner electromagnetic coil. Although designed for electric propulsion thrusters in spacecraft station- keeping, orbit transfer, and interplanetary applications, the LaB6 cathodes are applicable to the plasma processing industry in applications such as optical coatings and semiconductor processing where reactive gases are used. Where current electrical propulsion thrusters with BaO emitters have limited life and need extremely clean propellant feed systems at a significant cost, these LaB6 cathodes can run on the crudest-grade xenon propellant available without impact. Moreover, in a laboratory environment, LaB6 cathodes reduce testing costs because they do not require extended conditioning periods under hard vacuum. Alternative rare earth emitters, such as cerium hexaboride (CeB6) can be used in this

  16. Conceptual design of parallel beam lines for tandem accelerator

    International Nuclear Information System (INIS)

    In order to get enough beam current for each parallel beam line, the beam intensity distribution along aperture on the diaphragm is calculated to deduce a function which is verified by computer program for simulating charged particle beam transport systems, based on this function relationship between emittance of beam and the different aperture parameters on diaphragm is analyzed. At the end, a conceptual design of parallel beam line is given and the parameters of the optical elements are calculated. The results are accurate and credible. quality of beam can reach the requirements of user for nuclear physics experiments. (authors)

  17. Profile and Emittance Measurements at the CERN LINAC4 3 MeV test Stand

    CERN Document Server

    Zocca, F; Duraffourg, M; Focker, GJ; Gerard, D; Raich, U; Roncarolo, F

    2013-01-01

    A new 160 MeV H- Linac named Linac-4 will be built at CERN to replace the old 50 MeV proton Linac. The ion source, the 3 MeV Radio Frequency Quadrupole (RFQ) and the Medium Energy Beam Transport (MEBT) line hosting a chopper, have been commissioned in a dedicated test stand. Wire grids and wire scanners were used to measure the transverse beam profile and a slit/grid emittance meter was installed on a temporary test bench plugged at the RFQ and MEBT exit in different stages. The emittance meter slit was also used as a scanning scraper able to reconstruct the transverse profile by measuring the transmission with a downstream current transformer. On the same measurement bench, a spectrometer in conjunction with a wire grid allowed measuring the energy spread of the particles. This paper summarizes the measurement results that allowed characterizing the 3 MeV beam and discusses the present understanding of monitor performance.

  18. Accelerator Physical Issues of PETRA III - A New Low Emittance Light Source

    International Nuclear Information System (INIS)

    The reconstruction of the 2304 m long existing storage ring PETRA II into a dedicated Light Source PETRA III is presented. Envisaged is a machine with an energy of 6 GeV and an emittance of 1 nmrad operating with a current of at least 100 mA. The ring will provide 9 straight sections for the installation of undulators. For this purpose one eights of PETRA will be converted into a section of DBA cells. Two modes of operation are foreseen. One with a very high number of bunches and a second one with a considerably lower number of bunches allowing time resolved measurements. In the later mode the Touschek effect severely limits the beam lifetime to the order of an hour. To compensate for the rapid losses a frequent refilling of the machine is necessary. This procedure is usually called topping up mode. The low emittance in combination with the optics at the insertion devices leads to very small beam dimensions especially in the vertical plane. Therefore a sophisticated beam position control system is mandatory. To combat the multi bunch instabilities driven by the higher order modes of the cavities a powerful wideband feedback system is required

  19. Beam-beam effects

    Energy Technology Data Exchange (ETDEWEB)

    Zholents, A.

    1994-12-01

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

  20. 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.