Design features and operational characteristics of the PEP beam-transport and injection system

International Nuclear Information System (INIS)

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

1981-03-01

The PEP beam-transport system was designed to transmit 4-to-15 GeV electron and positron beams from the SLAC linac within a +- 0.8% momentum band, to have flexible tuning of the betatron and off-momentum functions for matching into the PEP storage ring, and to have convenient operating characteristics. The transport lines were brought into operation quickly and have operated well. Electron injection has been consistent and efficient and relatively easy to accomplish. Positron injection also has been satisfactory but is variable and more sensitive to ring conditions

Beam-plasma interaction in case of injection of the electron beam to the symmetrically open plasma system

International Nuclear Information System (INIS)

Opanasenko, A.V.; Romanyuk, L.I.

1992-01-01

A beam-plasma interaction at the entrance of the symmetrically open plasma system with an electron beam injected through it is investigated. An ignition of the plasma-beam discharge on waves of upper hybrid dispersion branch of a magnetoactive plasma is found in the plasma penetrating into the vacuum contrary to the beam. It is shown that the beam-plasma discharge is localized in the inhomogeneous penetrating plasma in the zone where only these waves exist. Regularities of the beam-plasma discharge ignition and manifestation are described. It is determined that the electron beam crossing the discharge zone leads to the strong energy relaxation of the beam. It is shown possible to control the beam-plasma discharge ignition by changing the potential of the electron beam collector. (author)

Conceptual design for the ZEPHYR neutral-beam injection system

International Nuclear Information System (INIS)

Cooper, W.S.; Elischer, V.P.; Goldberg, D.A.; Hopkins, D.B.; Jacobson, V.L.; Lou, K.H.; Tanabe, J.T.

1981-03-01

In June 1980, the Lawrence Berkeley Laboratory began a conceptual design study for a neutral beam injection system for the ZEPHYR ignition tokamak proposed by the Max-Planck-Institut fur Plasmaphysik in Garching, Germany. The ZEPHYR project was cancelled, and the LBL design effort concluded prematurely in January 1981. This report describes the conceptual design as it existed at that time, and gives brief consideration to a schedule, but does not deal with costs

SPS transverse beam scraping and LHC injection losses

CERN Document Server

Drosdal, L; Bartmann, W; Bracco, C; Cornelis, K; Goddard, B; Meddahi, M; Veyrunes, E

2012-01-01

Machine protection sets strict requirements for the quality of the injected beam, in particular in the transverse plane. Losses at aperture restrictions and protection elements have to be kept at a minimum. Particles in the beam tails are lost at the tight transfer line collimators and can trigger the LHC beam abort system. These particles have to be removed by scrapers in the vertical and horizontal plane in the SPS. Scraping has become vital for high intensity LHC operation. This paper shows the dependence of injection quality on the SPS scraping and discusses an improved scraper setting up strategy for better reproducibility with the current scraper system.

Antiproton Production beam and Reverse Injection System

Energy Technology Data Exchange (ETDEWEB)

Chadwick, G.

1981-08-16

The objectives of this project are two fold: (1) To extract high energy protons from the Main Ring (MR) and target them to produce antiprotons which are subsequently captured in the existing Booster accelerator; and (2) to provide a channel for injecting either protons or antiprotons into the MR from the booster in a direction opposite to that of the normal proton acceleration as colliding beams can be created. The present design, therefore, is in support of two separate larger projects, viz., the collisions of protons in the Tevatron (normal circulation direction) with 'reverse injected' protons in the MR, and the collision of normal direction protons with reverse injected antiprotons either in the MR or in the Tevatron. Figure 1 shows the layout of the project area. It spans the shortest distance between possible injection/ejection points in the existing accelerator structures, hence minimizing costs. The tunnel will lie underground at the level of the MR and booster.

Operation and Development on the Positive-Ion Based Neutral Beam Injection System for JT-60 and JT-60U

International Nuclear Information System (INIS)

Kuriyama, M.; Akino, N.; Ebisawa, N.; Honda, A.; Itoh, T.; Kawai, M.; Mogaki, K.; Ohga, T.; Oohara, H.; Umeda, N.; Usui, K.; Yamamoto, M.; Yamamoto, T.; Matsuoka, M.

2002-01-01

The positive-ion based neutral beam injection (NBI) system for JT-60, which consists of 14 beamline units and has a beam energy of 70 to 100 keV, started operation in 1986 with hydrogen beams and injected a neutral beam power of 27 MW at 75 keV into the JT-60 plasma. In 1991, the NBI system was modified to be able to handle deuterium beams as part of the JT-60 upgrade modification. After executing some research and developments, deuterium beams of 40 MW at 95 keV were injected in 1996. As a result, NBI has contributed to the achievement of the highest performance plasmas, a DT-equivalent fusion power gain of 1.25 and a fusion triple product of 1.55 x 10 21 keVs/m 3 , in the world on JT-60U

Neutral beam injection optimization at TJ-II

International Nuclear Information System (INIS)

Fuentes, C.; Liniers, M.; Wolfers, G.; Alonso, J.; Marcon, G.; Carrasco, R.; Guasp, J.; Acedo, M.; Sanchez, E.; Medrano, M.; Garcia, A.; Doncel, J.; Alejaldre, C.; Tsai, C.C.; Barber, G.; Sparks, D.

2005-01-01

Neutral beam injection (NBI) heating has been used on the TJ-II stellarator for the first time. The beam has a port-through power between 200 and 400 kW and injection energy 28 kV. Beam transmission is limited by beam interception at the injection port and the first toroidal field coil, therefore, beam steering optimization is of critical importance. The beam interaction areas inside TJ-II vacuum chamber are surveyed by infrared thermography. Beam reionization can be a problem due to the presence of residual gas in the duct region. Halpha emission is used to monitor the reionization at the duct. A careful optimization of the injected gas has been carried out

Neutral beam injection in 2XIIB

International Nuclear Information System (INIS)

Hibbs, S.M.

1975-01-01

Integrated into the operation of the 2XIIB controlled fusion experiment is a 600-A, 20-keV neutral injection system: the highest neutral-beam current capacity of any existing fusion machine. This paper outlines the requirements of the injection system and the design features to which they led. Both mechanical and electrical aspects are discussed. Also included is a brief description of some operational aspects of the system and some of the things we have learned along the way, as well as a short history of the most significant developments

Sensibility Studies for the Neutral Beam Injection System in TJ-II

International Nuclear Information System (INIS)

Fuentes, C.; Liniers, M.; Guasp, J.

1999-01-01

The sensibility of the Neutral Beam Injection system of TJ-II to the changes of several parameters is analysed. Transmission, absorption and power loads at the intercepting structures are evaluated. The adopted values for the ion source distance, focal length and divergence are confirmed as optimal, showing a small sensitivity to changes, except for the divergence. The operational margins for beam misalignments has been found to be small but feasible, confirming also the reference directions as optimal. Finally four possible alternatives, intended to reduce the power loads at the beam entering structures, are analysed. All of them have been discarded since lead to the appearance of new risk zones, with unacceptable load levels, and reduce the transmitted power. (Author) 13 refs

Operating characteristics of a new ion source for KSTAR neutral beam injection system.

Science.gov (United States)

Kim, Tae-Seong; Jeong, Seung Ho; Chang, Doo-Hee; Lee, Kwang Won; In, Sang-Ryul

2014-02-01

A new positive ion source for the Korea Superconducting Tokamak Advanced Research neutral beam injection (KSTAR NBI-1) system was designed, fabricated, and assembled in 2011. The characteristics of the arc discharge and beam extraction were investigated using hydrogen and helium gas to find the optimum operating parameters of the arc power, filament voltage, gas pressure, extracting voltage, accelerating voltage, and decelerating voltage at the neutral beam test stand at the Korea Atomic Energy Research Institute in 2012. Based on the optimum operating condition, the new ion source was then conditioned, and performance tests were primarily finished. The accelerator system with enlarged apertures can extract a maximum 65 A ion beam with a beam energy of 100 keV. The arc efficiency and optimum beam perveance, at which the beam divergence is at a minimum, are estimated to be 1.0 A/kW and 2.5 uP, respectively. The beam extraction tests show that the design goal of delivering a 2 MW deuterium neutral beam into the KSTAR Tokamak plasma is achievable.

BEAMS3D Neutral Beam Injection Model

Energy Technology Data Exchange (ETDEWEB)

Lazerson, Samuel

2014-04-14

With the advent of applied 3D fi elds in Tokamaks and modern high performance stellarators, a need has arisen to address non-axisymmetric effects on neutral beam heating and fueling. We report on the development of a fully 3D neutral beam injection (NBI) model, BEAMS3D, which addresses this need by coupling 3D equilibria to a guiding center code capable of modeling neutral and charged particle trajectories across the separatrix and into the plasma core. Ionization, neutralization, charge-exchange, viscous velocity reduction, and pitch angle scattering are modeled with the ADAS atomic physics database [1]. Benchmark calculations are presented to validate the collisionless particle orbits, neutral beam injection model, frictional drag, and pitch angle scattering effects. A calculation of neutral beam heating in the NCSX device is performed, highlighting the capability of the code to handle 3D magnetic fields.

First neutral beam injection experiments on KSTAR tokamaka)

Science.gov (United States)

Jeong, S. H.; Chang, D. H.; Kim, T. S.; In, S. R.; Lee, K. W.; Jin, J. T.; Chang, D. S.; Oh, B. H.; Bae, Y. S.; Kim, J. S.; Park, H. T.; Watanabe, K.; Inoue, T.; Kashiwagi, M.; Dairaku, M.; Tobari, H.; Hanada, M.

2012-02-01

The first neutral beam (NB) injection system of the Korea Superconducting Tokamak Advanced Research (KSTAR) tokamak was partially completed in 2010 with only 1/3 of its full design capability, and NB heating experiments were carried out during the 2010 KSTAR operation campaign. The ion source is composed of a JAEA bucket plasma generator and a KAERI large multi-aperture accelerator assembly, which is designed to deliver a 1.5 MW, NB power of deuterium at 95 keV. Before the beam injection experiments, discharge, and beam extraction characteristics of the ion source were investigated. The ion source has good beam optics in a broad range of beam perveance. The optimum perveance is 1.1-1.3 μP, and the minimum beam divergence angle measured by the Doppler shift spectroscopy is 0.8°. The ion species ratio is D+:D2+:D3+ = 75:20:5 at beam current density of 85 mA/cm2. The arc efficiency is more than 1.0 A/kW. In the 2010 KSTAR campaign, a deuterium NB power of 0.7-1.5 MW was successfully injected into the KSTAR plasma with a beam energy of 70-90 keV. L-H transitions were observed within a wide range of beam powers relative to a threshold value. The edge pedestal formation in the Ti and Te profiles was verified through CES and electron cyclotron emission diagnostics. In every deuterium NB injection, a burst of D-D neutrons was recorded, and increases in the ion temperature and plasma stored energy were found.

Design of the ESCAR injection beam line

International Nuclear Information System (INIS)

Tanabe, J.; Staples, J.; Yourd, R.

1975-01-01

The design features of the elements of the ESCAR (Experimental Superconducting Accelerator Ring) injection beam line are described. The junction of the proton transport system with the ESCAR injection straight section requires the design of mechanical elements compatible with the 10 -11 torr vacuum requirements of the main ring. These elements include a novel septum magnet whose salient design features include a current-carrying septum of tapered thicknesses to reduce the overall power requirements and total enclosure of the magnet coil in a metal can for vacuum compatibility. Other elements are a wire electro-static septum and several fast-rise ''bump magnets''. A transition cryopump is designed to separate the main ring vacuum from the relatively poor 10 -6 torr vacuum of the conventional beam transport line. A brief description of the conventional beam transport line from the 50 MeV proton linac, recently installed for Bevatron injection,is also included. (U.S.)

Five second helium neutral beam injection using argon-frost cryopumping techniques

International Nuclear Information System (INIS)

Phillips, J.C.; Kellman, D.H.; Hong, R.; Kim, J.; Laughon, G.M.

1995-10-01

High power helium neutral beams for the heating of tokamak discharges can now be provided for 5 s by using argon cryopumping (of the helium gas) in the beamlines. A system has now been installed to deposit a layer of argon frost on the DIII-D neutral beam cryopanels, between tokamak injection pulses. The layer serves to trap helium on the cryopanels providing sufficient pumping speed for 5 s helium beam extraction. The argon frosting hardware is now present on two of four DIII-D neutral beamlines, allowing injection of up to 6 MW of helium neutral beams per discharge, with pulse lengths of up to 5 s. The argon frosting system is described, along with experimental results demonstrating its effectiveness as a method of economically extending the capabilities of cryogenic pumping panels to allow multi-second helium neutral beam injection

Injection system of teh SSC Medium Energy Booster

International Nuclear Information System (INIS)

Mao, N.; Gerig, R.; McGill, J.; Brown, K.

1994-04-01

The Medium Energy Booster (MEB) is the third of the SSCL accelerators and the largest of the resistive magnet synchrotrons. It accelerates protons from an injection momentum of 12 GeV/c to a top momentum of 200 GeV/c. A beam injection system has been designed to inject the beam transferred from the Low Energy Booster onto the MEB closed orbit in the MEB injection insertion region. The beam is injected via a vertical bending Lambertson septum magnet and a horizontal kicker with appropriate matching and very little beam loss and emittance dilution. The beam optics of the injection system is described in this paper. The required parameters of the Lambertson septum magnet and the injection kicker are given

First neutral beam injection experiments on KSTAR tokamak.

Science.gov (United States)

Jeong, S H; Chang, D H; Kim, T S; In, S R; Lee, K W; Jin, J T; Chang, D S; Oh, B H; Bae, Y S; Kim, J S; Park, H T; Watanabe, K; Inoue, T; Kashiwagi, M; Dairaku, M; Tobari, H; Hanada, M

2012-02-01

The first neutral beam (NB) injection system of the Korea Superconducting Tokamak Advanced Research (KSTAR) tokamak was partially completed in 2010 with only 1∕3 of its full design capability, and NB heating experiments were carried out during the 2010 KSTAR operation campaign. The ion source is composed of a JAEA bucket plasma generator and a KAERI large multi-aperture accelerator assembly, which is designed to deliver a 1.5 MW, NB power of deuterium at 95 keV. Before the beam injection experiments, discharge, and beam extraction characteristics of the ion source were investigated. The ion source has good beam optics in a broad range of beam perveance. The optimum perveance is 1.1-1.3 μP, and the minimum beam divergence angle measured by the Doppler shift spectroscopy is 0.8°. The ion species ratio is D(+):D(2)(+):D(3)(+) = 75:20:5 at beam current density of 85 mA/cm(2). The arc efficiency is more than 1.0 A∕kW. In the 2010 KSTAR campaign, a deuterium NB power of 0.7-1.5 MW was successfully injected into the KSTAR plasma with a beam energy of 70-90 keV. L-H transitions were observed within a wide range of beam powers relative to a threshold value. The edge pedestal formation in the T(i) and T(e) profiles was verified through CES and electron cyclotron emission diagnostics. In every deuterium NB injection, a burst of D-D neutrons was recorded, and increases in the ion temperature and plasma stored energy were found.

Neutral beam injection on the PLT tokamak

International Nuclear Information System (INIS)

Schilling, G.; Ashcroft, D.L.; Eubank, H.P.; Grisham, L.R.; Knauer, R.C.; Stewart, L.D.; Stooksberry, R.W.; Ulrickson, M.; Williams, M.D.

1981-01-01

We describe the operation of the neutral beam injection system on the PLT tokamak. Improvements, retrofits, and conditioning have changed the injection system from an experiment in itself to a fairly reliable and useful plasma heating tool. We will present a brief overview of our physics achievements and then describe the system as it exists now. This will include injector performance, conditioning needs, maintenance needs, reliability, and daily operating sequences. We will also include hardware modifications and additions, electrical and mechanical, and point out remaining problem areas

Beam-beam dynamics during the injection process at the PEP-II B-Factory

International Nuclear Information System (INIS)

Chin, Yong Ho.

1991-10-01

This paper is concerned with beam-beam effects during the injection process at the proposed asymmetric SLAC/LBL/LLNL B-Factory based on PEP (PEP-2). For symmetric colliders, the primary source of the beam-beam effect is the head-on collision at the interaction point (IP), and this effect can be mitigated by separating the beams during the injection process. For an asymmetric collider, which intrinsically consists of two separate rings, the bunches not only collide at the IP but experience a long-range beam-beam force on the way into and out of the IP region. These collisions are called ''parasitic crossings (PC).'' The parasitic crossings emerge as a potential source of far stronger beam-beam impact during the injection process for the following reason. In the proposed injection scheme of the APIARY-6.3d design, the bunches are injected horizontally into the two rings with large horizontal offset of 8σ Ox sptm where σ Ox sptm is the nominal horizontal storage ring beam size at the end of the septum magnet. Then, the injected beam starts to travel around the ring oscillating horizontally. For the sake of discussion, let us assume that the beam in the other ring has already been fully stored. When the injected beam arrives at the 1st PC, where the two nominal orbits are separated horizontally by about 7.6 times the nominal horizontal beam size of the low energy ring, it may pass through the other beam far more closely than at the nominal separation distance, or it may even strike the other beam head-on

Five second helium neutral beam injection using argon-frost cryopumping techniques

International Nuclear Information System (INIS)

Phillips, J.C.; Kellman, D.H.; Hong, R.; Kim, J.; Laughon, G.M.

1995-01-01

High power helium neutral beams for the heating of tokamak discharges can now be provided for 5 s by using argon cryopumping (of the helium gas) in the beamlines. The DIII-D neutral beam system has routinely provided up to 20 MW of deuterium neutral beam heating in support of experiments on the DIII-D tokamak. Operation of neutral beams with helium has historically presented a problem in that pulse lengths have been limited to 500 ms due to reliance solely on volume pumping of the helium gas. Helium is not condensed on the cryopanels. A system has now been installed to deposit a layer of argon frost on the DIII-D neutral beam cryopanels, between tokamak injection pulses. The layer serves to trap helium on the cryopanels providing sufficient pumping speed for 5 s helium beam extraction. The argon frosting hardware is now present on two of four DIII-D neutral beamlines, allowing injection of up to 6 MW of helium neutral beams per discharge, with pulse lengths of up to 5 s. The argon frosting system is described, along with experimental results demonstrating its effectiveness as a method of economically extending the capabilities of cryogenic pumping panels to allow multi-second helium neutral beam injection

Feasibility Study of the PS Injection for 2 GeV LIU Beams with an Upgraded KFA-45 Injection Kicker System Operating in Short Circuit Mode

CERN Document Server

Kramer, Thomas; Borburgh, Jan; Ducimetière, Laurent; Feliciano, Luis; Ferrero Colomo, Alvaro; Goddard, Brennan; Sermeus, Luc

2016-01-01

Under the scope of the LIU project the CERN PS Booster to PS beam transfer will be modified to match the requirements for the future 2 GeV beams. This paper describes the evaluation of the proposed upgrade of the PS injection kicker. Different schemes of an injection for LIU beams into the PS have been outlined in the past already under the aspect of individual transfer kicker rise and fall time performances. Homogeneous rise and fall time requirements in the whole PSB to PS transfer chain have been established which allowed to consider an upgrade option of the present injection kicker system operated in short circuit mode. The challenging pulse quality constraints require an improvement of the flat top and post pulse ripples. Both operation modes, terminated and short circuit mode are analysed and analogue circuit simulations for the present and upgraded system are outlined. Recent measurements on the installed kickers are presented and analysed together with the simulation data. First measurements verifying...

Thermo-mechanical analysis of an acceleration grid for the international thermonuclear experimental reactor-neutral beam injection system

International Nuclear Information System (INIS)

Fujiwara, Yukio; Hanada, Masaya; Okumura, Yoshikazu; Suzuki, Satoshi; Watanabe, Kazuhiro

2001-01-01

In the engineering design of a negative-ion beam source for a high-power neutral beam injection (NBI) system, one of the most important issues is thermo-mechanical design of acceleration grids for producing several tens of MW ion beams. An acceleration grid for the international thermonuclear experimental reactor-neutral beam injection (ITER-NBI) system will be subjected to the heat loading as high as 1.5 MW. In the present paper, thermo-mechanical characteristics of the acceleration grid for the ITER-NBI system were analyzed. Numerical simulation indicated that maximum aperture-axis displacement of the acceleration grid due to thermal expansion would be about 0.7 mm for the heat loading of 1.5 MW. From the thin lens theory of beam optics, beamlet deflection angle by the aperture-axis displacement was estimated to be about 2 mrad, which is within the requirement of the engineering design of the ITER-NBI system. Numerical simulation also indicated that no melting on the acceleration grid would occur for a heat loading of 1.5 MW, while local plastic deformation would happen. To avoid the plastic deformation, it is necessary to reduce the heat loading onto the acceleration grid to less than 1 MW

Comparison of beam deposition for three neutral beam injection codes

International Nuclear Information System (INIS)

Wieland, R.M.; Houlberg, W.A.; Mense, A.T.

1979-03-01

The three neutral beam injection codes BEAM (Houlberg, ORNL), HOFR (Howe, ORNL), and FREYA (Post, PPPL) are compared with respect to the calculation of the fast ion deposition profile H(r). Only plasmas of circular cross section are considered, with injection confined to the mid-plane of the torus. The approximations inherent in each code are pointed out, and a series of comparisons varying several parameters (beam energy and radius, machine size, and injection angle) shows excellent agreement among all the codes. A cost comparison (execution time and memory requirements) is made which points out the relative merits of each code within the context of incorporation into a plasma transport simulation code

Diagnosing the PEP-II Injection System

Energy Technology Data Exchange (ETDEWEB)

Decker, F.-J.; Donald, M.H.; Iverson, R.H.; Kulikov, A.; Pappas, G.C.; Weaver, M.; /SLAC

2005-05-09

The injection of beam into the PEP-II B-Factory, especially into the High Energy Ring (HER) has some challenges. A high background level in the BaBar detector has for a while inhibited us from trickling charge into the HER similar to the Low Energy Ring (LER). Analyzing the injection system has revealed many issues which could be improved. The injection bump between two kickers was not closed, mainly because the phase advance wasn't exactly 180{sup o} and the two kicker strengths were not balanced. Additionally we found reflections which kick the stored beam after the main kick and cause the average luminosity to drop about 3% for a 10 Hz injection rate. The strength of the overall kick is nearly twice as high as the design, indicating a much bigger effective septum thickness. Compared with single beam the background is worse when the HER beam is colliding with the LER beam. This hints that the beam-beam force and the observed vertical blow-up in the HER pushes the beam and especially the injected beam further out to the edge of the dynamic aperture or beyond.

Diagnosing the PEP-II Injection System

International Nuclear Information System (INIS)

Decker, F.-J.; Donald, M.H.; Iverson, R.H.; Kulikov, A.; Pappas, G.C.; Weaver, M.; SLAC

2005-01-01

The injection of beam into the PEP-II B-Factory, especially into the High Energy Ring (HER) has some challenges. A high background level in the BaBar detector has for a while inhibited us from trickling charge into the HER similar to the Low Energy Ring (LER). Analyzing the injection system has revealed many issues which could be improved. The injection bump between two kickers was not closed, mainly because the phase advance wasn't exactly 180 o and the two kicker strengths were not balanced. Additionally we found reflections which kick the stored beam after the main kick and cause the average luminosity to drop about 3% for a 10 Hz injection rate. The strength of the overall kick is nearly twice as high as the design, indicating a much bigger effective septum thickness. Compared with single beam the background is worse when the HER beam is colliding with the LER beam. This hints that the beam-beam force and the observed vertical blow-up in the HER pushes the beam and especially the injected beam further out to the edge of the dynamic aperture or beyond

LHC Injection Beam Quality During LHC Run I

CERN Document Server

AUTHOR|(CDS)2079186; Kain, Verena; Stapnes, Steinar

The LHC at CERN was designed to accelerate proton beams from 450 GeV to 7 TeV and collide them in four large experiments. The 450 GeV beam is extracted from the last pre-accelerator, the SPS, and injected into the LHC via two 3 km long transfer lines, TI 2 and TI 8. The injection process is critical in terms of preservation of beam quality and machine protection. During LHC Run I (2009-2013) the LHC was filled with twelve high intensity injections per ring, in batches of up to 144 bunches of 1.7*10^11 protons per bunch. The stored beam energy of such a batch is already an order of magnitude above the damage level of accelerator equipment. Strict quality and machine protection requirements at injection have a significant impact on operational efficiency. During the first years of LHC operation, the injection phase was identified as one of the limiting factors for fast LHC turnaround time. The LHC Injection Quality Check (IQC) software framework was developed as a part of this thesis to monitor the beam quality...

Beam-plasma interaction with an electron beam injecting into a symmetrically open plasma system; Electron beam relaxation. Puchkovo-plazmennoe vzaimodejstvie pri inzhektsii ehlektronnogo puchka v simmetrichno otkrytuyu plazmennuyu sistemu; Relaksatsiya ehlektronnogo puchka

Energy Technology Data Exchange (ETDEWEB)

Opanasenko, A V; Romanyuk, L I [AN Ukrainskoj SSR, Kiev (Ukrainian SSR). Inst. Yadernykh Issledovanij

1989-10-01

The relaxation of the electron beam with the electron density of 1-2 keV injected through the symmetrically open plasma system with the independent hot cathode Penning discharge is experimentally investigated. It is shown that the velocity distribution function of the electron beam changes after passing each wave generation zone induced by the beam. The contribution of different wave zones to the beam relaxation depends on the prehistory of the beam-plasma interaction and may be regulated by the selection of the plasma system parameters. By this way the complete relaxation of the electron beam can be achieved after the beam crossing the whole system.

The PEP injection system

International Nuclear Information System (INIS)

Brown, K.L.; Avery, R.T.; Peterson, J.M.

1988-01-01

A system to transport 10-to-15-GeV electron and positron beams from the Stanford Linear Accelerator and to inject them into the PEP storage ring under a wide variety of lattice configurations has been designed. Optically, the transport line consists of three 360/degree/ phase-shift sections of FODO lattice, with bending magnets interspersed in such a way as to provide achromaticity, convenience in energy and emittance definition, and independent tuning of the various optical parameters for matching into the ring. The last 360/degree/ of phase shift has 88 milliradians of bend in a vertical plane and deposits the beam at the injection septum via a Lambertson magnet. Injection is accomplished by launching the beam with several centimeters of radial betatron amplitude in a fast bump provided by a triad of pulsed kicker magnets. Radiation damping reduces the collective amplitude quickly enough to allow injection at a high repetition rate

Mixed deuterium-tritium neutral beam injection

International Nuclear Information System (INIS)

Ruby, L.; Lewis, M.S.

1989-01-01

An alternative mixed beam neutral beam injector (MNBI) for fusion reactors is proposed that eliminates the conventional isotope separation system (ISS) in the fuel cycle. The principal advantage of the alternative system is a capital and operating cost savings in the fuel cycle, as the ISS employs cryogenic distillation at liquid-hydrogen temperatures to effect a separation of hydrogen isotopes and to eliminate a buildup of normal hydrogen in the recycled fuel. Possible additional advantages of the alternative method involve an improvement in overall safety and a reduction of the amount of tritium in the fuel cycle. The alternative heating system uses an electromagnetic separation in the MNBI to limit the buildup of normal hydrogen. Calculations indicate that an MNBI can be reasonably optimized in the case of an upgraded injection system for the Tokamak Fusion Test Reactor

Effects of parasitic beam-beam interaction during the injection process at the PEP-II B Factory

International Nuclear Information System (INIS)

Chin, Y.H.

1992-06-01

This paper is concerned with beam-beam effects during the injection process at the proposed asymmetric SLAC/LBL/LLNL B-Factory, PEP-II. It is shown that the parasitic beam-beam interaction can lead to a significant blowup in the vertical size of the injected beam. Simulation results for the horizontal and the vertical injection schemes are presented, and their performances are studied

Use of off-axis injection as an alternative to geometrically merging beams in an energy-recovering linac

Science.gov (United States)

Douglas, David R [York County, VA

2012-01-10

A method of using off-axis particle beam injection in energy-recovering linear accelerators that increases operational efficiency while eliminating the need to merge the high energy re-circulating beam with an injected low energy beam. In this arrangement, the high energy re-circulating beam and the low energy beam are manipulated such that they are within a predetermined distance from one another and then the two immerged beams are injected into the linac and propagated through the system. The configuration permits injection without geometric beam merging as well as decelerated beam extraction without the use of typical beamline elements.

Operational considerations for the PSB H- Injection System

CERN Document Server

Weterings, W; Borburgh, J; Carli, C; Fowler, T; Goddard, B

2010-01-01

For the LINAC4 project the PS Booster (PSB) injection system will be upgraded. The 160 MeV Hbeam will be distributed to the 4 superimposed PSB synchrotron rings and horizontally injected by means of an H- charge-exchange system. Operational considerations for the injection system are presented, including expected beam losses from unwanted field stripping of H- and excited H0 and foil scattering, possible injection failure cases and expected stripping foil lifetimes. Loading assumptions for the internal beam dumps are discussed together with estimates of doses on various components.

Beam Scraping to detect and remove Halo in LHC Injection

CERN Document Server

Letnes, P A; Brielmann, A; Burkhardt, H; Kramer, Daniel

2008-01-01

Fast scrapers are installed in the SPS to detect and remove beam halo before extraction of beams to the LHC, to minimize the probability for quenching of superconducting magnets in the LHC. We shortly describe the current system and then focus on our recent work, which aims at providing a system which can be used as operational tool for standard LHC injection. A new control application was written and tested with the beam. We describe the current status and results and compare these with detailed simulations.

Results and analysis of the TMX electron-beam injection experiments

International Nuclear Information System (INIS)

Poulsen, P.; Grubb, D.P.

1980-01-01

Electron beams (e-beams) were injected into the Tandem Mirror Experiment (TMX) plasma in order to investigate the effect on the ion cyclotron fluctuations of the plasma. The power level of the e-beams was comparable to that of the injected neutral beams. It was found that injection of the e-beams produced no significant effect on the ion cyclotron fluctuations, the measured plasma parameters, or the particle and power flow of the plasma. The increase in bulk electron temperature and the production of mirror-confined electrons found in previous experiments in which e-beams were injected into a mirror-confined plasma were not observed in this experiment. Analysis of the regions and frequencies of wave creation and absorption within the plasma shows that the plasma density and magnetic field profiles through the plasma strongly affect the resonances encountered by the waves. The steep axial density profiles produced by neutral-beam injection in the TMX experiment are not conducive to efficient coupling of the e-beam energy to the plasma

Neutral beam injection system design for KSTAR tokamak

Energy Technology Data Exchange (ETDEWEB)

Choi, B.H.; Lee, K.W.; Chung, K.S.; Oh, B.H.; Cho, Y.S.; Bae, Y.D.; Han, J.M. [Korea Atomic Energy Research Institute, Taejon (Korea)

1998-06-01

The NBI system for KSTAR (Korean Superconducting Tokamak Advanced Research) has been designed based on conventional positive ion beam technology. One beam line consists of three ion sources, three neutralizers, one bending magnet, and one drift tube. This system will deliver 8 MW deuterium beam to KSTAR plasma in normal operation to support the advanced experiments on heating, current drive and profile control. The key technical issues in this design were high power ion source(120 kV, 65 A), long pulse operation (300 seconds; world record is 30 sec), and beam rotation from vertical to horizontal direction. The suggested important R and D points on ion source and beam line components are also included. (author). 7 refs., 27 figs., 1 tab.

An RF driven H- source and a low energy beam injection system for RFQ operation

International Nuclear Information System (INIS)

Leung, K.N.; Bachman, D.A.; Chan, C.F.; McDonald, D.S.

1992-01-01

An RF driven H - source has been developed at LBL for use in the Superconducting Super Collider (SSC). To date, an H - current of ∼40 mA can be obtained from a 5.6-cm-diam aperture with the source operated at a pressure of about 12 m Torr and 50 kW of RF power. In order to match the accelerated H - beam into the SSC RFQ, a low-energy H - injection system has been designed. This injector produces an outgoing H - beam free of electron contamination, with small radius, large convergent angle and small projectional emittance

Injection of an electron beam into a plasma and spacecraft charging

International Nuclear Information System (INIS)

Okuda, H.; Kan, J.R.

1987-01-01

Injection of a nonrelativistic electron beam into a fully ionized plasma from a spacecraft including the effect of charging has been studied using a one-dimensional particle simulation model. It is found that the spacecraft charging remains negligible and the beam can propagate into a plasma, if the beam density is much smaller than the ambient density. When the injection current is increased by increasing the beam density, significant spacecraft charging takes place and the reflection of beam electrons back to the spacecraft reduces the beam current significantly. On the other hand, if the injection current is increased by increasing the beam energy, spacecraft charging remains negligible and a beam current much larger than the thermal return current can be injected. It is shown that the electric field caused by the beam--plasma instability accelerates the ambient electrons toward the spacecraft thereby enhancing the return current

Injection and Dump Systems

CERN Document Server

Bracco, C; Barnes, M J; Carlier, E; Drosdal, L N; Goddard, B; Kain, V; Meddahi, M; Mertens, V; Uythoven, J

2012-01-01

Performance and failures of the LHC injection and ex- traction systems are presented. In particular, a comparison with the 2010 run, lessons learnt during operation with high intensity beams and foreseen upgrades are described. UFOs, vacuum and impedance problems related to the injection and extraction equipment are analysed together with possible improvements and solutions. New implemented features, diagnostics, critical issues of XPOC and IQC applications are addressed.

Injection and propagation of a nonrelativistic electron beam and spacecraft charging

International Nuclear Information System (INIS)

Okuda, H.; Berchem, J.

1987-05-01

Two-dimensional numerical simulations have been carried out in order to study the injection and propagation of a nonrelativistic electron beam from a spacecraft into a fully ionized plasma in a magnetic field. Contrary to the earlier results in one-dimension, a high density electron beam whose density is comparable to the ambient density can propagate into a plasma. A strong radial electric field resulting from the net charges in the beam causes the beam electrons to spread radially reducing the beam density. When the injection current exceeds the return current, significant charging of the spacecraft is observed along with the reflection of the injected electrons back to the spacecraft. Recent data on the electron beam injection from the Spacelab 1 (SEPAC) are discussed

Efficient Injection of Electron Beams into Magnetic Guide Fields

International Nuclear Information System (INIS)

Chorny, V.; Cooperstein, G.; Dubyna, V.; Frolov, O.; Harper-Slaboszewicz, V.; Hinshelwood, D.; Schneider, R.; Solovyov, V.; Tsepilov, H.; Vitkovitsky, I.; Ware, K.

1999-01-01

Preliminary experimental and modeling study of injection and transport of high current electron beams in current-neutralized background gas has been performed. Initial analysis of the results indicates that high current triaxial ring diode operates very reproducibly in the pinch mode. High current density beam can be injected efficiently into the drift region, using azimuthal guide field with reduced intensity near the injection region. This was shown to improve the effectiveness of capturing the beam for the transport. The transport length was insufficient to measure losses, such as would arise from scattering with the background gas

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

Science.gov (United States)

Hatakeyama, Shuichiro; Toyama, Takeshi

Beam power of J-PARC MR (30 GeV Proton Synchrotron Main Ring) has been improved since 2008 and now achieved over 200 kW for the user operation. A part of beam loss is localized at the beam injection phase so it is important to monitor the beam bunch behavior in the transverse direction. In this paper it is described the method how to measure the position and momentum for each injected beam bunch using Beam Position Monitors (BPMs). It is also mentioned some implementation of an operator's interface (OPI) to display the plots of injected and circulating beam bunches in phase space coordinate.

Increased power delivery from the DIII-D neutral beam injection system

International Nuclear Information System (INIS)

Colleraine, A.P.; Callis, R.W.; Hong, R.M.; Kellman, D.H.; Kim, J.; Langhorn, A.R.; Lee, R.; Phillips, J.C.; Wight, J.J.

1989-12-01

The neutral beam system installed on the DIII-D tokamak employs eight 80 kV Long Pulse Sources (LPS) mounted on four beamlines and was originally designed to deliver a nominal 12 MW of H degree power to a plasma for pulses of up to 5 sec duration. Lawrence Berkeley Laboratory designed the LPS for the US Fusion Program to fill the requirements of both the DIII-D and the TFTR machines. Essentially all source components are of a common design; the DIII-D version is therefore conservative in its rated parameters. Recently a neutron shield has been constructed around the torus hall allowing D degree injection to become routine. Because deuterium beams have a better neutralization efficiency, the nominal power delivery per source has been measured to be approximately 2 MW (for a total of 16 MW) without any modifications. However, by reoptimizing the voltage gradients in the source, the perveance can be increased without degrading the optics. A change of gradient grid voltage from 0.83 V accel to 0.79 V accel raises the perveance from 2.5 to 3.0 μPerv with a corresponding gain in beam power of about 20%. The arc power required also must be increased to the range of 100 to 120 kW but this is well within the design limits of the LPS. Further studies of our systems are now underway to assess the possibilities of raising V accel above 80 kV. An additional gain in power is possible by this technique. 6 refs., 6 figs

The kicker magnet system for TRISTAN Accumulation Ring injection

International Nuclear Information System (INIS)

Sakamoto, Y.; Satoh, K.; Nakayama, H.

1994-12-01

The injection of electron beams to TRISTAN Accumulation Ring (AR) was started in November 1983 and the positron injection started in November 1985. For the injection of electron and positron beams to AR, the unique kicker system was developed. In the kicker power supply the charging to the main capacitor was done with the resonant charge system together with the auxiliary charging unit. The impedance matching circuit was added to the kicker magnet for getting the required current form with least reflecting oscillation. In this paper we report the performance of this kicker system. (author)

The Beam Screen for the LHC Injection Kicker Magnets

CERN Document Server

Barnes, MJ; Ducimetière, L; Garrel, N; Kroyer, T

2006-01-01

The two LHC injection kicker magnet systems must each produce a kick of 1.2 T.m with a flattop duration variable up to 7.86 ìs, and rise and fall times of less than 0.9 ìs and 3 ìs, respectively. Each system is composed of four 5 Ù transmission line kicker magnets with matched terminating resistors and pulse forming networks (PFN). The LHC beam has a high intensity, hence a beam screen is required in the aperture of the magnets This screen consists of a ceramic tube with conducting ?stripes? on the inner wall. The stripes provide a path for the image current of the beam and screen the magnet ferrites against Wake fields. The stripes initially used gave adequately low beam impedance however stripe discharges occured during pulsing of the magnet: hence further development of the beam screen was undertaken. This paper presents options considered to meet the often conflicting needs for low beam impedance, shielding of the ferrite, fast field rise time and good electrical and vacuum behaviour.

Laser fusion: an assessment of pellet injection, tracking and beam pointing

International Nuclear Information System (INIS)

Monsler, M.J.

1978-01-01

A conceptual design is presented for a target injection and final optical system which can be integrated with a lithium waterfall laser fusion reactor and operate repetitively within the presented tolerances. A high f-number focusing system using coated metal optics at 30 to 60 meters distance is suggested. An intermediate section of the differentially pumped beam tube contains flowing xenon which effectively shields the optics from debris and x rays, allowing the mirrors to operate at least a year without optical degradation. Pellets are injected with a repeating gas gun positioned horizontally just above the laser beam. No pellet trajectory correction is desired or required. Simple tracking of the target using a low power laser illuminator, a position sensing photodetector, and a trajectory prediction scheme are assumed. Two-degree of freedom x-y beam steering is preferred, without focus capability. Both the tracker and the adaptive mirror are placed in the laser building, well away from the fixed final optical mirror which faces the microexplosion

Bootstrap current of fast ions in neutral beam injection heating

International Nuclear Information System (INIS)

Huang Qianhong; Gong Xueyu; Yang Lei; Li Xinxia; Lu Xingqiang; Yu Jun

2012-01-01

The bootstrap current of fast ions produced by the neutral beam injection is investigated in a large aspect ratio tokamak with circular cross-section under specific parameters. The bootstrap current density distribution and the total bootstrap current are figured out. In addition, the beam bootstrap current always accompanies the electron return current due to the parallel momentum transfer from fast ions. With the electron return current considered, the net current density obviously decreases due to electron return current, at the same time the peak of current moves towards the centre plasma. Numerical results show that the value of the net current depends sensitively not only on the angle of the neutral beam injection but also on the ratio of the velocity of fast ions to the critical velocity: the value of net current is small for the neutral beam parallel injection but increases multipliedly for perpendicular injection, and increases with beam energy increasing. (authors)

Acceleration of laser-injected electron beams in an electron-beam driven plasma wakefield accelerator

International Nuclear Information System (INIS)

Knetsch, Alexander

2018-03-01

Plasma wakefields deliver accelerating fields that are approximately a 100 times higher than those in conventional radiofrequency or even superconducting radiofrequency cavities. This opens a transformative path towards novel, compact and potentially ubiquitous accelerators. These prospects, and the increasing demand for electron accelerator beamtime for various applications in natural, material and life sciences, motivate the research and development on novel plasma-based accelerator concepts. However, these electron beam sources need to be understood and controlled. The focus of this thesis is on electron beam-driven plasma wakefield acceleration (PWFA) and the controlled injection and acceleration of secondary electron bunches in the accelerating wake fields by means of a short-pulse near-infrared laser. Two laser-triggered injection methods are explored. The first one is the Trojan Horse Injection, which relies on very good alignment and timing control between electron beam and laser pulse and then promises electron bunches with hitherto unprecedented quality as regards emittance and brightness. The physics of electron injection in the Trojan Horse case is explored with a focus on the final longitudinal bunch length. Then a theoretical and numerical study is presented that examines the physics of Trojan Horse injection when performed in an expanding wake generated by a smooth density down-ramp. The benefits are radically decreased drive-electron bunch requirements and a unique bunch-length control that enables longitudinal electron-bunch shaping. The second laser-triggered injection method is the Plasma Torch Injection, which is a versatile, all-optical laser-plasma-based method capable to realize tunable density downramp injection. At the SLAC National Laboratory, the first proof-of-principle was achieved both for Trojan Horse and Plasma Torch injection. Setup details and results are reported in the experimental part of the thesis along with the commissioning

Refined Calculation of Beam Dynamics During UMER Injection

CERN Document Server

Bai, Gang; Godlove, Terry; Haber, Irving; Kishek, Rami A; Quinn, Bryan; Reiser, Martin; Thangaraj, Jayakar C T; Walter, Mark

2005-01-01

The University of Maryland Electron Ring (UMER) is built as a low-cost testbed for intense beam physics for benefit of larger ion accelerators. The beam intensity is designed to be variable, spanning the entire range from low current operation to highly space-charge-dominated transport. The ring has recently been closed and multi-turn commissioning has begun. Although we have conducted many experiments at high space charge during UMER construction, lower-current beams have become quite useful in this commissioning stage for assisting us with beam steering, measurement of phase advance, etc. One of the biggest challenges of multi-turn operation of UMER is correctly operating the Y-shaped injection section, hence called the Y-section, which is specially designed for UMER multi-turn operation. It is a challenge because the system requires several quadrupoles and dipoles in a very stringent space, resulting in mechanical, electrical, and beam control complexities. This paper presents a simulation study of the bea...

Performance of the ALS injection system

International Nuclear Information System (INIS)

Kim, C.H.

1993-05-01

The authors started commissioning the Advanced Light Source (ALS) storage ring on January 11, 1993. The stored beam reached 60 mA on March 24, 1993 and 407 mA on April 9, 1993. The fast pace of storage ring commissioning can be attributed partially to the robust injection system. In this paper they describe the operating characteristics of the ALS injection system

Thermal analysis of injection beam dump of high-intensity rapid-cycling synchrotron in J-PARC

Science.gov (United States)

Kamiya, J.; Saha, P. K.; Yamamoto, K.; Kinsho, M.; Nihei, T.

2017-10-01

The beam dump at the beam injection area in the J-PARC 3-GeV rapid cycling synchrotron (RCS) accepts beams that pass through the charge exchange foil without ideal electron stripping during the multi-turn beam injection. The injection beam dump consists of the beam pipe, beam stopper, radiation shield, and cooling mechanism. The ideal beam power into the injection beam dump is 400 W in the case of design RCS extraction beam power of 1 MW with a healthy foil, which has 99.7 % charge stripping efficiency. On the other hand, as a radiation generator, the RCS is permitted to be operated with maximum average beam power of 4 kW into the injection beam dump based on the radiation shielding calculation, in consideration of lower charge stripping efficiency due to the foil deterioration. In this research, to evaluate the health of the RCS injection beam dump system from the perspective of the heat generation, a thermal analysis was performed based on the actual configuration with sufficiently large region, including the surrounding concrete and soil. The calculated temperature and heat flux density distribution showed the validity of the mesh spacing and model range. The calculation result showed that the dumped 4 kW beam causes the temperature to increase up to 330, 400, and 140 °C at the beam pipe, beam stopper, and radiation shield, respectively. Although these high temperatures induce stress in the constituent materials, the calculated stress values were lower than the ultimate tensile strength of each material. Transient temperature analysis of the beam stopper, which simulated the sudden break of the charge stripper foil, demonstrated that one bunched beam pulse with the maximum beam power does not lead to a serious rise in the temperature of the beam stopper. Furthermore, from the measured outgassing rate of stainless steel at high temperature, the rise in beam line pressure due to additive outgassing from the heated beam pipe was estimated to have a negligible

Metal impurity injection into DIVA plasmas with a Q-switched laser beam

International Nuclear Information System (INIS)

Yamauchi, Toshihiko; Nagami, Masayuki; Sengoku, Seio; Kumagai, Katsuaki

1978-08-01

Metal impurity injection into DIVA plasmas with a Q-switched ruby laser beam is described. Metal materials used are aluminium and gold. The Q-switched laser beam is incident onto a thin metal film thickness about 0.2 μm coated on pyrex glass plate surface. The metal film is vaporized by the laser beam and injected into DIVA plasma. The laser-beam injection method has advantages of sharp profile of vaporized metal, easy control of vaporized metal quantity and injection rate control of metal vapor. (author)

PLT and Doublet III neutral beam injection systems

International Nuclear Information System (INIS)

Haselton, H.H.; Dagenhart, W.K.; Schechter, D.E.; Stewart, L.D.; Stirling, W.L.

1976-01-01

The design program is being supported by experimental work with all beam line components: gas cells, bending magnets, beam stops, magnetic shielding, and high speed-high throughput cryopumping systems. Stray toroidal fields and fields produced by external transmission or mirror magnets are under study to determine the optimum means of removing the unneutralized component from the beam. Concepts utilizing materials with high permeability are adequate to provide the source with the necessary magnetic shielding. Beam stops capable of dissipating a power density of 10 to 40 kW/cm 2 are required for ion dumps, diagnostics, and on line ion source conditioning

Development of KSTAR Neutral Beam Heating System

Energy Technology Data Exchange (ETDEWEB)

Oh, B. H.; Song, W. S.; Yoon, B. J. (and others)

2007-10-15

The prototype components of a neutral beam injection (NBI) system have been developed for the KSTAR, and a capability of the manufactured components has been tested. High power ion source, acceleration power supply, other ion source power supplies, neutralizer, bending magnet for ion beam separation, calorimeter, and cryo-sorption pump have been developed by using the domestic technologies and tested for a neutral beam injection of 8 MW per beamline with a pulse duration of 300 seconds. The developed components have been continuously upgraded to achieve the design requirements. The development technology of high power and long pulse neutral beam injection system has been proved with the achievement of 5.2 MW output for a short pulse length and 1.6 MW output for a pulse length of 300 seconds. Using these development technologies, the domestic NB technology has been stabilized under the development of high power ion source, NB beamline components, high voltage and current power supplies, NB diagnostics, NB system operation and control.

The Booster to AGS beam transfer fast kicker systems

International Nuclear Information System (INIS)

Zhang, W.; Bunicci, J.; Soukas, A.V.; Zhang, S.Y.

1992-01-01

The Brookhaven AGS Booster has a very successful commissioning period in June 1991. The third phase of that commissioning was a beam extraction test. The Booster extraction fast kicker (F3) deflected a 1.2 GeV proton beam from the Booster circulating orbit into the extraction septum aperture, partially down the extraction line to a temporary beam stop. Now, the Booster is committed to the AGS operations program for both heavy ion and proton beams. Thus, the Booster extraction and the corresponding AGS injection systems must operate routinely up to a pulse repetition frequency of 7.5 Hertz, and up to a beam energy of 1.5 Gev. The injection fast kicker is located in the A5 section of the AGS ring and is used to deflect the proton or heavy ion beam into its final AGS closed orbit. A distinctive feature of the AGS injection fast kicker modulators is the tail-bitting function required for proton beam injection. This enables the system to produce a fast current fall time to go along with the high current pulse amplitude with a fast rise time. The AGS injection fast kicker system has three pulse modulators, and each modulator consists of two thyratrons. The main PFN thyratrons switch on the current, and the tail bitting thyratrons are used to force the magnet current to decrease rapidly. Two digital pulse delay generators are used to align the main thyratrons and the tail bitting thyratrons respectively. The system has been tested and installed. The final commissioning of the Booster to AGS beam transfer line and injection is currently being undertaken. In this article, the system design, realization techniques and performance data will be presented

The PEP II injection kicker system

International Nuclear Information System (INIS)

Pappas, G.C.; Donaldson, A.R.; Williams, D.

1997-07-01

PEP II or the B Factory consists of two asymmetric storage rings. The injection energy for electrons is 9 GeV, while that for positrons is 3.1 GeV. The bend angle into the high energy ring (HER) is 0.35 m-rad, and the angle into the low energy ring (LER) is 0.575 m-rad. The magnetic length for the HER kicker is 0.85 m, and 0.55 m for the LER kicker. The field produced by the magnet is therefore 123.5 G for the HER, and 132 G for the LER. Each ring has a kicker magnet upstream of the injection line which is used to distort the orbit of the stored beam. An identical magnet downstream of the injection line is used to restore the orbit of the stored beam and inject the incoming beam. The two magnets are driven in parallel by the modulator. The apeture of the magnets is 3.86x3.46 cm (HxV). Therefore the current required to drive the HER is 863 A, while for the LER it is 756 A. The inductance of the magnet is approximately 1.4 uH/m. The current pulse is a critically damped sinusoid with a rise time of less than 300 ns. A kicker system has been designed which can be used for injection of both beams by varying the charge of voltage. The modulator uses a conjugate circuit to match the impedance of the magnet, and coupling to the beam chamber

Mechanical design for modification of a neutral beam for off-axis injection

Energy Technology Data Exchange (ETDEWEB)

Anderson, P.M. [General Atomics, P.O. Box 85608, San Diego, CA 92186-5608 (United States)], E-mail: anderson@fusion.gat.com; Hong, R.-M. [General Atomics, P.O. Box 85608, San Diego, CA 92186-5608 (United States)

2009-06-15

DIII-D is planning to implement off-axis neutral beam current drive by neutral beam injection through a midplane port at angles up to 15 deg. from horizontal. To accommodate the beam-line tilting, the following modifications are planned: (1) move the beam line away from the tokamak by 0.39 m to allow for a 0.68 m inside diameter welded bellows of necessary length to provide 15 deg. of vertical motion between the vessel port and the beam line; (2) reduce the vertical height of the injected beam from 0.48 m to 0.43 m to provide clearance for the inclined beam as it passes through the length of the vessel port; (3) add a linkage system between the front of the beam line and the tokamak to restrain the NB against the vacuum loading from the bellows while maintaining zero roll about the axis of the beam line as it is moved about a virtual pivot axis; (4) add a forward and two rear vertical actuators for raising and lowering the beam line (These actuators require coordinated position control to rotate the NB about a virtual pivot axis.); (5) incorporate lateral restraint to comply with seismic requirements.

Beam based systems and controls

CERN Document Server

Jacquet, D

2012-01-01

This presentation will give a review from the operations team of the performance and issues of the beam based systems, namely RF, ADT, beam instrumentation, controls and injection systems. For each of these systems, statistics on performance and availability will be presented with the main issues encountered in 2012. The possible improvements for operational efficiency and safety will be discussed, with an attempt to answer the question "Are we ready for the new challenges brought by the 25ns beam and increased energy after LSI? ".

A review of JAERI R and D activities on the negative-ion-based neutral beam injection system

International Nuclear Information System (INIS)

Ohara, Yoshihiro; Akiba, Masato; Araki, Masanori

1990-08-01

R and D efforts to realize a negative-ion-based neutral beam injection system have been made intensively at JAERI for the past several years. Concerning a high current negative ion source which is one of the most important R and D items, a 10 A, 50 keV negative hydrogen ion beam has been produced successfully. The negative ion beam current and the current density correspond already to the value required for the negative-ion-based NBI system. In order to increase the beam energy further, a 350 keV, 0.1 A test stand has been constructed, and the test of a high energy negative ion accelerator has started. Concerning a high energy acceleration power supply, an inverter type power supply which has a high speed AC switch was proposed and applied to the 100 kV, 5 A power supply for JAERI Electron Beam Irradiation Stand. The reliable operation indicates that the concept of this system can be applied for a MV class acceleration power supply. As one of the promising candidates for a beam dump cooling element, an externally-finned swirl tube was proposed and tested to have a high burnout heat flux of 4.1 kW/cm 2 , which is high enough for the next NBI system. The R and Ds on the negative-ion-based NBI system have made great progress at JAERI in recent years. The construction of a 500 keV class NBI system has become realistic from the engineering point of view. (author)

A new dual injection system for AMS facility

International Nuclear Information System (INIS)

Liu Lin; Zhou Weijian; Cheng Peng; Yu Huagui; Chen Maobai

2007-01-01

In order to measure long-lived radioisotopes such as 10 Be with high sensitivity using an HVEE model 4130 AMS system, as well as to guarantee 14 C measurements of high precision, a new dual injection system for the AMS system is proposed. The proposal is to add a Wien filter located between the ion source system and the recombinator of the HVEE model 4130. When a pulsing voltage is optionally applied to the Wien filter, a sequential injection mode is turned on. The isotopes would alternately pass on different trajectories through the recombinator. When the pulsing voltage and magnetic field are turned off, the Wien filter acts as a field-free drift space and the standard simultaneous injection mode is on. Beam optics calculation show that the new dual injection system will increase the number of radio-nuclides which can be analyzed, keep the high precision capability for radiocarbon dating and achieve high sensitivity for 10 Be and 26 Al measurements, together with simplifying the layout as compared to existing dual-injector and dual high-energy beam line systems

An Improved Beam Screen for the LHC Injection Kickers

CERN Document Server

Barnes, M J; Ducimetière, L; Garrel, N; Kroyer, T

2007-01-01

The two LHC injection kicker magnet systems must produce a kick of 1.3 T.m with a flattop duration variable up to 7860 ns, and rise and fall times of less than 900 ns and 3000 ns, respectively. Each system is composed of two resonant charging power supplies (RCPSs) and four 5 WW transmission line kicker magnets with matched terminating resistors and pulse forming networks (PFNs). A beam screen is placed in the aperture of the magnets: the screen consists of a ceramic tube with conductors on the inner wall. The conductors provide a path for the image current of the, high intensity, LHC beam and screen the ferrite against Wake fields. The conductors initially used gave adequately low beam coupling impedance however inter-conductor discharges occurred during pulsing of the magnet: an alternative design was discharge free at the nominal operating voltage but the impedance was too high for the ultimate LHC beam. This paper presents the results of a new development undertaken to meet the often conflicting requireme...

Neutral-beam-injected tokamak fusion reactors: a review

International Nuclear Information System (INIS)

Jassby, D.L.

1976-08-01

The theories of energetic-ion velocity distributions, stability, injection, and orbits were summarized. The many-faceted role of the energetic ions in plasma heating, fueling, and current maintenance, as well as in the direct enhancement of fusion power multiplication and power density, is discussed in detail for three reactor types. The relevant implications of recent experimental results on several beam-injected tokamaks are examined. The behavior of energetic ions is found to be in accordance with classical theory, large total ion energy densities are readily achieved, and plasma equilibrium and stability are maintained. The status of neutral-beam injectors and of conceptual design studies of beam-driven reactors are briefly reviewed. The principal plasma-engineering problems are those associated directly with achieving quasi-stationary operation

FAFNER - a fully 3-D neutral beam injection code using Monte Carlo methods

International Nuclear Information System (INIS)

Lister, G.G.

1985-01-01

A computer code is described which models the injection of fast neutral particles into 3-dimensional toroidal plasmas and follows the paths of the resulting fast ions until they are either lost to the system or fully thermalised. A comprehensive model for the neutral beam injection system is included. The code is written especially for the use on the CRAY-1 computer: in particular, the modular nature of the program should enable the most time consuming sections of the program to be vectorised for each particular experiment to be modelled. The effects of plasma contamination by possible injection of impurities, such as oxygen, with the beams are also included. The code may also be readily adapted to plasmas for which a 1 or 2-dimensional description is adequate. It has also been constructed with a view to ready coupling with a transport or equilibrium code. (orig.)

Crystal Collimation with Lead Ion Beams at Injection Energy in the LHC

CERN Document Server

Rossi, Roberto; Andreassen, Arvid; Butcher, Mark; Dionisio Barreto, Cristovao Andre; Masi, Alessandro; Mirarchi, Daniele; Montesano, Simone; Lamas Garcia, Inigo; Redaelli, Stefano; Scandale, Walter; Serrano Galvez, Pablo; Rijllart, Adriaan; Valentino, Gianluca; Galluccio, Francesca; CERN. Geneva. ATS Department

2015-01-01

During this MD, performed on December 2nd 2015, bent silicon crystals were tested with ion beams for a possible usage of crystal-assisted collimation. Tests were performed at injection energy, using both horizontal and vertical crystals. Ion channeling was observed for the first time with LHC beams at the record energy of 450 GeV and the channeled beams were probed with scans performed with secondary collimators. Measurements of cleaning efficiency of a crystal-based collimation system were also performed.

Electron beam injection during active experiments. I - Electromagnetic wave emissions

Science.gov (United States)

Winglee, R. M.; Kellogg, P. J.

1990-01-01

The wave emissions produced in Echo 7 experiment by active injections of electron beams were investigated to determine the properties of the electromagnetic and electrostatic fields for both the field-aligned and cross-field injection in such experiments and to evaluate the sources of free energy and relative efficiencies for the generation of the VLF and HF emissions. It is shown that, for typical beam energies in active experiments, electromagnetic effects do not substantially change the bulk properties of the beam, spacecraft charging, and plasma particle acceleration. Through simulations, beam-generated whistlers; fundamental z-mode and harmonic x-mode radiation; and electrostatic electron-cyclotron, upper-hybrid, Langmuir, and lower-hybrid waves were identified. The characteristics of the observed wave spectra were found to be sensitive to both the ratio of the electron plasma frequency to the cyclotron frequency and the angle of injection relative to the magnetic field.

Bootstrap current of fast ions in neutral beam injection heating

International Nuclear Information System (INIS)

Huang Qianhong; Gong Xueyu; Li Xinxia; Yu Jun

2012-01-01

The bootstrap current of fast ions produced by neutral beam injection (NBI) is investigated in a large-aspect-ratio tokamak with circular cross-section under specific parameters. The bootstrap current density distribution and the total bootstrap current are reported. In addition, the beam bootstrap current always accompanies the electron return current due to the parallel momentum transfer from fast ions. With the electron return current taken into consideration, the net current density obviously decreases; at the same time, the peak of the current moves towards the central plasma. Numerical results show that the value of the net current depends sensitively not only on the angle of the NBI but also on the ratio of the velocity of fast ions to the critical velocity: the value of the net current is small for neutral beam parallel injection, but increases severalfold for perpendicular injection, and increases with increasing beam energy. (paper)

Neutral beam data systems at ORNL

International Nuclear Information System (INIS)

Stewart, C.R.

1982-01-01

A control system for neutral injection beam lines has been designed, implemented, and used with much success. Despite the problems with very high power levels this system is very successful in relieving the operators burdens of slow conditioning, data recording, and mode switching. The use of computer control with multiple beam lines now appears very promising

Selective injection locking of a multi-mode semiconductor laser to a multi-frequency reference beam

Science.gov (United States)

Pramod, Mysore Srinivas; Yang, Tao; Pandey, Kanhaiya; Giudici, Massimo; Wilkowski, David

2014-07-01

Injection locking is a well known and commonly used method for coherent light amplification. Usually injection locking is obtained on a single-mode laser injected by a single-frequency seeding beam. In this work we show that selective injection locking of a single-frequency may also be achieved on a multi-mode semiconductor laser injected by a multi-frequency seeding beam, if the slave laser provides sufficient frequency filtering. This selective injection locking condition depends critically on the frequency detuning between the free-running slave emission frequency and each injected frequency component. Stable selective injection locking to a set of three seeding components separated by 1.2 GHz is obtained. This system provides an amplification up to 37 dB of each component. This result suggests that, using distinct slave lasers for each frequency line, a set of mutually coherent high-power radiation modes can be tuned in the GHz frequency domain.

Ion transport studies on the PLT tokamak during neutral beam injection

International Nuclear Information System (INIS)

Suckewer, S.; Cavallo, A.; Cohen, S.

1983-12-01

Radial transport of ions during co- and counter-neutral beam heating in the PLT tokamak has been studied, using molybdenum and scandium ions as tracer elements. The time evolution of the radial profiles of several ionization stages of both elements, injected by laser blowoff during the neutral beam heating, were measured under three significantly different beam-plasma combinations. No noticeable differences in the radial profiles attributable to the beam direction were observed. However, a given injected amount resulted in considerably larger interior concentrations of the tracer element in the counter-beam heating cases, suggesting larger penetration of the plasma periphery. Computer simulation with the MIST code suggests a net inward drift of the order 10 3 cm/sec superposed to a diffusion coefficient of the order 10 4 cm 2 /sec for both scandium and molybdenum ions. Injection of larger amounts of the tracer element, sufficient to cause measurable central electron temperature changes, resulted in dramatic changes in ion-state distributions, making some appear peaked in the center while others disappeared. This effect could be produced with both co- and counter-beam heating, but with lesser amounts in the latter case. It is interpreted as rearrangement of the ionization balance, rather than any preferential accumulation of the injected element

Beam optics study of a negative ion source for neutral beam injection application at ASIPP

Energy Technology Data Exchange (ETDEWEB)

Wei, Jiang-Long; Liang, Li-Zhen [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Jiang, Cai-Chao [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Graduate school, University of Science and Technology of China, Hefei 230026 (China); Xie, Ya-Hong, E-mail: xieyh@ipp.ac.cn [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Hu, Chun-Dong; Li, Jun; Gu, Yu-Ming; Chen, Yu-Qian [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Li, Jing-Yong; Wu, Ming-Shan [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Graduate school, University of Science and Technology of China, Hefei 230026 (China)

2017-04-15

In order to study the generation and extraction of negative ions for neutral beam injection application, a negative ion source is being designed and constructed at Institute of Plasma Physics, Chinese Academy of Sciences (ASIPP). Through a four electrode grids system inside the accelerator, a negative ion beam will be extracted and accelerated up to −60 kV on a reduced scale extraction area of 12 × 50 cm{sup 2} (the area of PG apertures is 185 cm{sup 2}). The beam optics is a key issue for the accelerator design, and greatly determine the source experimental performance in term of beam current, heat load on the grid, beam divergence, and so on. In this paper, the trajectories of electrons and negative ions were simulated in the electrode grids of the negative ion source. The filter capability of electron deflection magnet on the co-extracted electrons is evaluated and confirmed. The negative ion beam optics was designed according to the calculated results of beam divergence and beam radius along the beamlet in different acceleration voltages. The deflection effect of the electron deflection magnet on the negative ion beam was investigated in the single beamlet case and multi-beamlets case.

Layout considerations for the PSB H- injection system

CERN Document Server

Aiba, M; Carli, C; Chanel, M; Fowler, A; Goddard, B; Weterings, W

2009-01-01

The layout of the PSB H- injection system is described, including the arguments for the geometry and the required equipment performance parameters. The longitudinal positions of the main elements are specified, together with the injected and circulating beam axes. The assumptions used in determining the geometry are listed.

Design of power supply system for the prototype RF-driven negative ion source for neutral beam injection application

Energy Technology Data Exchange (ETDEWEB)

Jiang, Caichao; Hu, Chundong [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Graduate school, University of Science and Technology of China, Hefei 230026 (China); Wei, Jianglong, E-mail: jlwei@ipp.ac.cn [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Xie, Yahong; Xu, Yongjian; Liang, Lizhen; Chen, Shiyong; Liu, Sheng; Liu, Zhimin; Xie, Yuanlai [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China)

2017-04-15

Highlights: • A supporting power supply system was designed in details for a RF-driven prototype negative ion source at ASIPP. • The RF power supply for plasma generation adopts an all-solid-state power supply structure. • The extraction grid power supply adopts the pulse step modulator (PSM) technology. - Abstract: In order to study the generation and extraction of negative ions for neutral beam injection application, a prototype RF-driven negative ion source and the corresponding test bed are under construction at Institute of Plasma Physics, Chinese Academy of Sciences (ASIPP). The target of the negative ion source is extracting a negation ion beam of 350 A/m{sup 2} for 3600 s plasma duration and 100 s beam duration. According to the required parameters of test bed, the design of power supply system is put forward for earlier study. In this paper, the performance requirements and design schemes of RF power supply for plasma generation, impedance matching network, bias voltage power supply, and extraction voltage power supply for negative beam extraction are introduced in details. The schemes provide a reference for the construction of power supply system and lay a foundation for the next phase of experimental operation.

An intense polarized beam by a laser ionization injection

International Nuclear Information System (INIS)

Ohmori, Chihiro; Hiramatsu, Shigenori; Nakamura, Takeshi.

1990-12-01

Accumulation of protons and polarized protons by photo-ionization injection are described. This method consists of (1)producing the neutral hydrogen beam by Lorentz stripping, (2)excitation of the neutral hydrogen beam with a laser, and (3)ionization of the hydrogen beam in the 2P excited state with another laser. When the laser for the excitation is circularly polarized, we can get a polarized proton beam. An ionization efficiency of 98% and a polarization of 80% can be expected by an intense laser beam from a FEL(Free Electron Laser). (author)

Gas injection in EBT-S for assessment of particle loading effects of neutral beam injection

International Nuclear Information System (INIS)

Carpenter, K.H.; Glowienka, J.C.

1979-01-01

Experiments have begun to examine the physics of neutral beam injection on EBT-S. Preliminary experiments have been limited to a calibrated gas puffing experiment which simulates the effects of a pulsed beam with zero energy. These experiments begin to address some of the compatibility problems that exist for future beam heating experiments on EBT devices. In particular, neutral beams are to be a significant part of the planned EBT-II experiment which is designed to demonstrate steady-state, reactor-like conditions with both electron cyclotron heating and neutral beam heating

Study of RF system of Hefei storage ring under injection

International Nuclear Information System (INIS)

Xu Hongliang; Wang Lin; Li Yongjun; Huang Guirong; Zhang Pengfei; Li Weimin; Liu Zuping; He Duohui

2004-01-01

In this paper, the beam loading effect of RF system and the conditions of Robinson instability are analyzed in detail. By the study of the injection beam intensity limit dependent on detune angle and visible detune angle, it is found that the storage ring can be injected to more than 300 mA current intensity to attain the design target of phase II project in the lower energy injection situation of Hefei Storage Ring if a certain power is feed in the RF cavity and a certain tuning angle of the RF cavity is set

Neutral beam injection and plasma convection in a magnetic field

International Nuclear Information System (INIS)

Okuda, H.; Hiroe, S.

1988-06-01

Injection of a neutral beam into a plasma in a magnetic field has been studied by means of numerical plasma simulations. It is found that, in the absence of a rotational transform, the convection electric field arising from the polarization charges at the edges of the beam is dissipated by turbulent plasma convection, leading to anomalous plasma diffusion across the magnetic field. The convection electric field increases with the beam density and beam energy. In the presence of a rotational transform, polarization charges can be neutralized by the electron motion along the magnetic field. Even in the presence of a rotational transform, a steady-state convection electric field and, hence, anomalous plasma diffusion can develop when a neutral beam is constantly injected into a plasma. Theoretical investigations on the convection electric field are described for a plasma in the presence of rotational transform. 11 refs., 19 figs

Los Alamos Proton Storage Ring (PSR) injection deflector system

International Nuclear Information System (INIS)

Jason, A.j.; Higgins, E.F.; Koelle, A.R.

1983-01-01

We describe a pulsed magnetic deflector system planned for the injection system of the PSR. Two sets of magnets, appropriately placed in the optical systems of both the ring and the injection transport line, provide control of the rate at which particles are injected into a given portion of transverse phase space and limit the interaction of stored beam with the injection stripping foil. High-current modulators that produce relatively complex waveforms are required for this purpose. Solid-state drivers using direct feedback to produce the necessary waveforms are discussed as replacements for the more conventional high-voltage tube technology

Treatment of H0 and H- beams spilled at the stripper foil at full energy charge-exchange injection scheme

International Nuclear Information System (INIS)

Yamane, Isao

1991-01-01

The charge-exchange injection into a synchrotron to generate high-intensity pulsed proton beams for a spallation neutron source is reviewed while focusing on the treatment of H 0 and H - beams spilled at the stripper foil. After charge-exchange injection is briefly outlined, scattering by foil atoms and causes to spill H 0 and H - beams are described. These spilled beams can amount to several μA and should be carefully treated. It is then shown that a direct H - injection system needs to be considerably long and requires a very long straight section. Because of its simplicity, two-step H 0 injection has very wide applicability to various types of rings. However, it has a problem of emittance growth due to angular divergence in the stripper magnet and an ionoptical mismatch at the stripper foil. These problems are discussed, including a new proposal for a measure to remedy this problem. The laser photoionization injection is also briefly mentioned. (author)

TRANSIENT BEAM LOADING EFFECTS IN RF SYSTEMS IN JLEIC

Energy Technology Data Exchange (ETDEWEB)

Wang, Haipeng [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Guo, Jiquan [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Rimmer, Robert A. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Wang, Shaoheng [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)

2016-05-01

The pulsed electron bunch trains generated from the Continuous Electron Beam Accelerator Facility (CEBAF) linac to inject into the proposed Jefferson Lab Electron Ion Collider (JLEIC) e-ring will produce transient beam loading effects in the Superconducting Radio Frequency (SRF) systems that, if not mitigated, could cause unacceptably large beam energy deviation in the injection capture, or exceed the energy acceptance of CEBAF’s recirculating arcs. In the electron storage ring, the beam abort or ion clearing gaps or uneven bucket filling can cause large beam phase transients in the (S)RF cavity control systems and even beam loss due to Robinson instability. We have first analysed the beam stability criteria in steady state and estimated the transient effect in Feedforward and Feedback RF controls. Initial analytical models for these effects are shown for the design of the JLEIC e-ring from 3GeV to 12GeV.

Doppler-shift spectra of Hα lines from negative-ion-based neutral beams for large helical device neutral beam injection

International Nuclear Information System (INIS)

Oka, Y.; Ikeda, K.; Takeiri, Y.; Tsumori, K.; Kaneko, O.; Nagaoka, K.; Osakabe, M.; Asano, E.; Kondo, T.; Sato, M.; Shibuya, M.; Grisham, L.; Umeda, N.; Honda, A.; Ikeda, Y.; Yamamoto, T.

2006-01-01

The velocity spectra of the negative-ion-(H - ) based neutral beams are studied in high-performance large-area ion sources during injection into large helical device fusion plasmas. We are conducting systematic observations in standard neutral beam injection to correlate beam spectra with source operating conditions. Almost all of the transmitted beam power was at full acceleration energy (∼170 keV). The small stripping beam component which was produced in the extraction gap was evaluated to be about 9%-22% by amplitude of the measured spectra for the sources in beam lines 1 and 2. H - production uniformity from the spectrum profile was 86%-90% for three sources. For the longest pulse injection during 74 and 128 s, a full energy component tended to decrease with time, while the accelerator gap stripping tail tended to increase slightly with time, which is attributed to beam-induced outgassing in the accelerator. A higher conductance multislot ground grid accelerator appeared to show little growth in the accelerator gap beam stripping during long pulses compared to the conventional multiaperture ground grid. The beam uniformity appeared to vary in part with the Cs uniformity on the plasma grid

TARA beamline and injection system

International Nuclear Information System (INIS)

Post, R.S.; Brindza, P.; Coleman, J.W.; Torti, R.P.; Blackfield, D.T.; Goodrich, P.

1983-01-01

The TARA beamline for neutral beam injection will permit one to three sources to fire into each plug (60 degree or optional 90 degree injection with respect to the TARA axis) or into each anchor (90 degree injection only). The sources, pre-aimed on their mounting plate at the NB test stand, may be fired into neutralizer ducts or optionally through a magnesium curtain, and the unneutralized fraction is dumped by the TARA fringing field onto a receiver plate. The beamline is housed in a cylindrical tank with the beam axis along the tank diameter at the midplane. The tank will be sorption pumped using LN + T/sub I/ or N/sub B/ and/or e-beam gettering. The beam burial tank contains sed arrays and a thin foil dump which reaches sufficiently high temperatures during the shot to boil out gas between shots

Impurity ion transport studies on the PLT tokamak during neutral-beam injection

International Nuclear Information System (INIS)

Suckewer, S.; Cavallo, A.; Cohen, S.

1984-01-01

Radial transport of medium- and high-Z ions during co- and counter-neutral-beam heating in the PLT tokamak is studied, using molybdenum and scandium ions as tracer elements. The time evolution of the radial profiles of several ionization stages of both elements, injected by laser blowoff during the neutral-beam heating, is measured under three significantly different beam-plasma combinations. No noticeable differences in the radial profiles attributable to the beam direction are observed. However, a given injected amount resulted in considerably larger interior concentrations of the tracer element in the counter-beam heating cases, suggesting larger penetration of the plasma periphery. Computer simulation with the MIST code suggests a net inward drift of the order 10 3 cm.s -1 superposed to a diffusion coefficient of the order 10 4 cm 2 .s -1 for both scandium and molybdenum ions. Injection of larger amounts of the tracer element, sufficient to cause measurable central electron temperature changes, resulted in dramatic changes in ion-state distributions, making some appear peaked in the centre while others disappeared. This effect could be produced with both co- and counter-beam heating, but with lesser amounts in the latter case. It is interpreted as rearrangement of the ionization balance, rather than any preferential accumulation of the injected element. (author)

Heating efficiency of high-power perpendicular neutral-beam injection in PDX

International Nuclear Information System (INIS)

Hawryluk, R.J.; Arunasalam, V.; Bell, M.

1982-03-01

The heating efficiency of high power (up to 7.2 MW) near-perpendicular neutral beam injection in the PDX tokamak is comparable to that of tangential injection in PLT. Collisionless plasmas with central ion temperatures up to 6.5 keV and central electron temperatures greater than 2.5 keV have been obtained. The plasma pressure, including the contribution from the beam particles, increases with increasing beam power and does not appear to saturate, although the parametric dependence of the energy confinement time is different from that observed in ohmic discharges

Beam Induced Ferrite Heating of the LHC Injection Kickers and Proposals for Improved Cooling

CERN Document Server

Barnes, M J; Calatroni, S; Day, H; Ducimetière, L; Garlaschè, M; Gomes Namora, V; Mertens, V; Sobiech, Z; Taborelli, M; Uythoven, J; Weterings, W

2013-01-01

The two LHC injection kicker systems produce an integrated field strength of 1.3 T·m with a flattop duration variable up to 7860 ns, and rise and fall times of less than 900 ns and 3000 ns, respectively. A beam screen is placed in the aperture of each magnet, which consists of a ceramic tube with conductors in the inner wall. The conductors provide a path for the beam image current and screen the ferrite yoke against wakefields. Recent LHC operation, with high intensity beam stable for many hours, resulted in significant heating of both the ferrite yoke and beam impedance reduction ferrites. For one kicker magnet the ferrite yoke approached its Curie temperature. As a result of a long thermal time-constant the ferrite yoke can require several hours to cool sufficiently to allow re-injection of beam, thus limiting the running efficiency of the LHC. Thermal measurement data has been analysed, a thermal model developed and emissivity measurements carried out. Various measures to improve the ferrite cooling have...

Design study of a neutral beam injection system for the JAERI Experimental Fusion Reactor (JXFR)

International Nuclear Information System (INIS)

1977-10-01

Design study has been made of a 200 kV, 45 MW D 0 neutral beam injection system for the JAERI Experimental Fusion Reactor (JXFR) covering the following: determination of the ion source specifications, design of components such as ion source with extraction electrodes, energy converter, cryopump and cooling system, and estimations of the energy conversion efficiency, overall power efficiency and total power required for operation of the NBI system, and also a hydrogen isotope separation method using cryo-sorption pumps. Optimizations and parameter studies of the neutralizing cell length, gas flow rate, operating pressure of ion sources, total pumping speed and pressure of energy converters are made in the design study based on reactor plasma requirements. Hollow cathode ion sources are proposed because of the extended operation time at low gas pressure (about 4.5 x 10 -3 Torr) and the high gas efficiency (40%). Life of the extraction electrodes is determined by blistering due to deuterium ions. Fast neutron radiation damage is relatively small. In-line direct converters with grounded recovery electrodes and neutralizing cells floated at negative potential -190 kV are used to recover residual deuterium ion energy without interrupting the neutral beam trajectories. Energy conversion efficiency of 80% and overall power efficiency of about 40% are obtained. (auth.)

The model of beam-plasma discharge in the rocket environment during an electron beam injection in the ionosphere

International Nuclear Information System (INIS)

Mishin, E.V.; Ruzhin, Yu.Ya.

1980-01-01

The model of beam-plasma discharge in the rocket environment during electron beam injection in the ionosphere is constructed. The discharge plasma density dependence on the neutral gas concentration and the beam parameters is found

Atmospheric Signatures and Effects of Space-based Relativistic Electron Beam Injection

Science.gov (United States)

Marshall, R. A.; Sanchez, E. R.; Kero, A.; Turunen, E. S.; Marsh, D. R.

2017-12-01

Future relativistic electron beam injection experiments have the potential to provide groundbreaking insights into the physics of wave-particle interactions and beam-neutral interactions, relevant to space physics and to fundamental plasma physics. However, these experiments are only useful if their signatures can be detected. In this work, we use a physics-based forward modeling framework to investigate the observable signatures of a relativistic beam interacting with the upper atmosphere. The modeling framework is based around the Electron Precipitation Monte Carlo (EPMC) model, used to simulate electron precipitation in the upper atmosphere. That model is coupled to physics-based models of i) optical emission production; ii) bremsstrahlung photon production and propagation; iii) D-region ion chemistry; and iv) VLF wave propagation in the Earth-ionosphere waveguide. Using these modeling tools, we predict the optical, X-ray, chemical, radar, and VLF signatures of a realistic beam injection, based on recent space-based accelerator designs. In particular, we inject a beam pulse of 10 mA for a duration of 500 μs at an energy of 1 MeV, providing a total pulse energy of 5 J. We further investigate variations in these parameters, in particular the total energy and the electron energy. Our modeling shows that for this 5 J pulse injection at 1 MeV electron energy, the optical signal is easily detectable from the ground in common emission bands, but the X-ray signal is likely too weak to be seen from either balloons or LEO orbiting spacecraft. We further predict the optical signal-to-noise ratio that would be expected in different optical systems. Chemical signatures such as changes to NOx and HOx concentrations are too short-lived to be detectable; however our modeling provides a valuable estimate of the total chemical response. Electron density perturbations should be easily measurable from ground-based high-power radars and via VLF subionospheric remote sensing

Experimental investigation of molecular beam injection in HL-1 tokamak

International Nuclear Information System (INIS)

Yao Lianghua; Diao Guangyao; Wang Zhanhe; Deng Huichen; Luo Junlin; Duan Xuru; Cui Zhengying

1993-07-01

A new method of gas puffing is presented. The molecular beam, formed by high pressure deuterium gas through Larval nozzle and skimmer slit, is injected into the HL-1 vacuum vessel. The deuterium molecular current from the nozzle passing through the skimmer is about 3 x 10 20 /s. At the line average electron density of 5.2 x 10 19 m -3 , the beam velocity is about 100 m/s. As the plasma density and temperature increasing, the influxes of deuterium particles attenuate quickly. When the molecular beam injection (MBI) just returned to normal gas puffing, the D α emission rapidly decreases, meanwhile, the particles move toward plasma center, the electron density is continuously peaking. The line average electron density rising lasts 45 ms. The thermal energy of plasma and confinement time for particles and energy are also increasing. the MBI is a direct and efficient gas fuelling mode, and the injected particles can reach to inside about 8 cm of plasma and q ≅ 2 confinement region. Its efficiency of injection is about 50%. After the MBI, the particle recycling coefficient R on the wall is 0.6 which is 10% lower than that of normal gas puffing

Optimization of parameters for the inline-injection system at Brookhaven Accelerator Test Facility

International Nuclear Information System (INIS)

Parsa, Z.; Ko, S.K.

1995-01-01

We present some of our parameter optimization results utilizing code PARMLEA, for the ATF Inline-Injection System. The new solenoid-Gun-Solenoid -- Drift-Linac Scheme would improve the beam quality needed for FEL and other experiments at ATF as compared to the beam quality of the original design injection system. To optimize the gain in the beam quality we have considered various parameters including the accelerating field gradient on the photoathode, the Solenoid field strengths, separation between the gun and entrance to the linac as well as the (type size) initial charge distributions. The effect of the changes in the parameters on the beam emittance is also given

Antiproton source beam position system

International Nuclear Information System (INIS)

Bagwell, T.; Holmes, S.; McCarthy, J.; Webber, R.

1984-05-01

The TeV I Beam Position Monitor (BPM) system is designed to provide a useful diagnostic tool during the commissioning and operational phases of the antiproton source. Simply stated the design goal is to provide single turn position information for intensities of > 1x10 9 particles, and multi-turn (clocked orbit) information for beam intensities of > 1x10 7 particles, both with sub-millimeter resolution. It is anticipated that the system will be used during commissioning for establishing the first turn through the Debuncher and Accumulator, for aligning injection orbits, for providing information necessary to correct closed orbits, and for measuring various machine parameters (e.g. tunes, dispersion, aperture, chromaticity). During normal antiproton operation the system will be used to monitor the beam position throughout the accumulation process

Empirical Scaling Laws of Neutral Beam Injection Power in HL-2A Tokamak

International Nuclear Information System (INIS)

Cao Jian-Yong; Wei Hui-Ling; Liu He; Yang Xian-Fu; Zou Gui-Qing; Yu Li-Ming; Li Qing; Luo Cui-Wen; Pan Yu-Dong; Jiang Shao-Feng; Lei Guang-Jiu; Li Bo; Rao Jun; Duan Xu-Ru

2015-01-01

We present an experimental method to obtain neutral beam injection (NBI) power scaling laws with operating parameters of the NBI system on HL-2A, including the beam divergence angle, the beam power transmission efficiency, the neutralization efficiency and so on. With the empirical scaling laws, the estimating power can be obtained in every shot of experiment on time, therefore the important parameters such as the energy confinement time can be obtained precisely. The simulation results by the tokamak simulation code (TSC) show that the evolution of the plasma parameters is in good agreement with the experimental results by using the NBI power from the empirical scaling law. (paper)

Injection control development of the JT-60U electron cyclotron heating system

Energy Technology Data Exchange (ETDEWEB)

Hiranai, Shinichi; Shinozaki, Shin-ichi; Yokokura, Kenji; Moriyama, Shinichi [Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan). Naka Fusion Research Establishment; Sato, Fumiaki [Nippon Advanced Technology Co., Ltd., Tokai, Ibaraki (Japan); Suzuki, Yasuo [Atomic Energy General Service Co., Ltd., Tokai, Ibaraki (Japan); Ikeda, Yoshitaka [Japan Atomic Energy Research Inst., Kashiwa, Chiba (Japan)

2003-03-01

The JT-60U electron cyclotron heating (ECH) System injects a millimeteric wave at 110 GHz into the JT-60 Plasma, and heats the plasma or drives a current locally to enhance the confinement performance of the JT-60 plasma. The system consists of four sets of high power gyrotrons, high voltage power supplies and transmission lines, and two antennas that launch electron cyclotron (EC) beams toward the plasma. The key features of the injection control system are streering of the direction of the EC beam by driving the movable mirror in the antenna, and capability to set any combination of polarization angle and ellipticity by rotating the two grooved mirrors in the polarizers. This report represents the design, fabrication and improvements of the injection control system. (author)

Heat flux to the limiter during disruptions and neutral beam injection in Doublet-III

International Nuclear Information System (INIS)

Hino, T.; DeGrassie, J.; Taylor, T.S.; Hopkins, G.; Meyer, C.; Petrie, T.W.; Kahn, C.L.; Ejima, S.

1984-01-01

The heat flux to the Doublet-III primary limiter has been monitored during plasma disruptions and during neutral beam injection. The surface temperature of the movable TiC-coated graphite limiter was measured with an Inframetrics thermal imaging system and a suitably filtered silicon photodiode spot detector. In addition, the floating electric potential of the limiter with respect to the vacuum vessel was measured. The heat pulse duration to the limiter was measured by the spot detector with a time response of x approx.= 10 μs and these times were correlated with the plasma parameters. In limiter discharges, 20% of the plasma kinetic stored energy goes to the limiter during disruptions. The power balance during disruptions is also discussed. During neutral beam injection, the limiter is not heated uniformly; the ion drift side receives much more thermal flux than the electron drift side. The fraction of beam power going to the limiter is as high as approx.= 35% in normal limiter discharges. (orig.)

External injection systems applied in modern cyclotrons designed and manufactured in NIIEFA

International Nuclear Information System (INIS)

Bogdanov, P.V.; Vasilchenko, I.N.; Veresov, O.L.; Gavrish, Yu.N.; Grigorenko, S.V.; Zuev, Yu.V.; Kozienko, M.T.; Mudrolyubov, V.G.; Strokach, A.P.; Tsygankov, S.S.

2012-01-01

The main parameters and design features of the external injection systems applied in modern cyclotrons designed and manufactured in NIIEFA and intended for production of radionuclides for medicine are presented. The use of these external injection systems instead of a traditional internal source allows the current of the accelerated beam to be significantly increased and the in-leakage of the working gas to the acceleration chamber to be reduced, which results in reduced beam losses in the process of acceleration and lower equipment activation.

Steel septum magnets for the LHC beam injection and extraction

CERN Document Server

Bidon, S; Guinand, M; Gyr, Marcel; Sassowsky, M; Weisse, E; Weterings, W; Abramov, A; Ivanenko, A I; Kolatcheva, E; Lapyguina, O; Ludmirsky, E; Mishina, N; Podlesny, P; Riabov, A; Tyurin, N

2002-01-01

The Large Hadron Collider (LHC) will be a superconducting accelerator and collider to be installed in the existing underground LEP ring tunnel at CERN. It will provide proton-proton collisions with a centre of mass energy of 14 TeV. The proton beams coming from the SPS will be injected into the LHC at 450 GeV by vertically deflecting kicker magnets and horizontally deflecting steel septum magnets (MSI). The proton beams will be dumped from the LHC with the help of two extraction systems comprising horizontally deflecting kicker magnets and vertically deflecting steel septum magnets (MSD). The MSI and MSD septa are laminated iron-dominated magnets using an all welded construction. The yokes are constructed from two different half cores, called coil core and septum core. The septum cores comprise circular holes for the circulating beams. This avoids the need for careful alignment of the usually wedge-shaped septum blades used in classical Lambertson magnets. The MSI and MSD septum magnets were designed and buil...

The Injection System of the INFN-SuperB Factory Project: Preliminary Design

Energy Technology Data Exchange (ETDEWEB)

Boni, Roberto; /INFN, Rome; Guiducci, Susanna; /INFN, Rome; Preger, Miro; /INFN, Rome; Raimondi, Pantaleo; /INFN, Rome; Chance, Antoine; /Saclay; Dadoun, Olivier; /Orsay, LAL; Poirier, Freddy; /Orsay, LAL; Variola, Alessandro; /Orsay, LAL; Seeman, John; /SLAC

2012-07-05

The ultra high luminosity B-factory (SuperB) project of INFN requires a high performance and reliable injection system, providing electrons at 4 GeV and positrons at 7 GeV, to fulfil the very tight requirements of the collider. Due to the short beam lifetime, continuous injection of electron and positron bunches in both LER and HER rings is necessary to maintain an high average luminosity. Polarized electrons are required for experiments and must be delivered by the injection system, due to the beam lifetime shorter than the ring polarization build-up: they will be produced by means of a SLAC-SLC polarized gun. The emittance and the energy spread of the e{sup -}/e{sup +} beams are reduced in a 1 GeV Damping Ring (DR) before injection in the main rings. Two schemes for positron production are under study, one with e{sup -}/e{sup +} conversion at low energy (< 1 Gev) and one with conversion at 6 GeV and a recirculation line to bring the positrons back to the DR. Acceleration through the Linac is provided by a 2856 MHz RF system made of travelling wave (TW), room temperature accelerating structures.

Online Measurement of the Energy Spread of Multi-Turn Beam in the Fermilab Booster at Injection

Energy Technology Data Exchange (ETDEWEB)

Nelson, J. [Brown U.; Bhat, C. M. [Fermilab; Hendricks, B. S. [Fermilab

2017-07-01

We have developed a computer program interfaced with the ACNET environment of Fermilab accelerators to measure energy spread of the proton beam from the LINAC at an injection into the Booster. It uses a digitizing oscilloscope and provides users an ability to configure the scope settings for optimal data acquisition from a resistive wall current monitor. When the program is launched, a) a one shot timeline is generated to initiate beam injection into the Booster, b) a gap of about 40 ns is produced in the injected beam using a set of fast kickers, c) collects line charge distribution data from the wall current monitor for the first 200 μs from the injection and d) performs complete data analysis to extract full beam energy spread of the beam. The program also gives the option to store the data for offline analyses. We illustrate a case with an example. We also present results on beam energy spread as a function of beam intensity from recent measurements.

Rocket potential measurements during electron beam injection into the ionosphere

International Nuclear Information System (INIS)

Gringauz, K.I.; Shutte, N.M.

1981-01-01

Electron flux measurements were made during pulsed injection of electron beams at a current of about 0.5 A and energy of 15 or 27 keV, using a retarding potential analyzer which was mounted on the lateral surface of the Eridan rocket during the ARAKS experiment of January 26, 1975. The general character of the retardation curves was found to be the same regardless of the electron injection energy, and regardless of the fact whether the plasma generator, injecting quasineutral cesium plasma with an ion current of about 10 A, was switched on. A sharp current increase in the interval between 10 to the -7th and 10 to the -6th A was observed with a decrease of the retarding potential. The rocket potential did not exceed approximately 150 V at about 130 to 190 km, and decreased to 20 V near 100 km. This was explained by the formation of a highly conducting region near the rocket, which was formed via intense plasma waves generated by the beam. Measurements of electron fluxes with energies of 1 to 3 keV agree well with estimates based on the beam plasma discharge theory

Nonlinear wave-beam kinetic equilibrium in decelerating systems

International Nuclear Information System (INIS)

Grishin, V.K.; Shaposhnikova, E.N.

1981-01-01

The equilibrium state of the wave-beam system arising during the interaction of a particle beam and excited electromagnetic wave has been investigated on the basis of the analysis of the exact polution of a non-linear self-consistent linear equation using the complete system of conservation laws. A waveguide with a dielectric filler, into which a monoenergetic particle beam magnetized in a transverse plane is continuously injected, is used as a model of an decelerating system. A dispersion equation describing the system state and expression for the evaluation of efficiency of the beam energy conversion to the field energy have been obtained. It is concluded that larae fields and high efficiency of energy conversion are achieved during the marked beam reconstruction. States with different values of current and beam velocity but similar amplitudes of a longitudinal field are possible in the system considered [ru

Confinement studies with neutral-beam injection on PDX and PLT

Energy Technology Data Exchange (ETDEWEB)

Goldston, R.; Kaye, S.; Davis, S.

1982-07-01

Neutral beam injection experiments on PLT and PDX have been conducted over a wider range in parameter space than previously. On PLT H/sup 0/ beams have been injected into well-confined high toroidal field, high density Ohmic plasmas, giving n/sub e/(0) tau/sub Ee/ products during injection of up to 5 x 10/sup 12/ sec cm/sup -3/. tau/sub Ee/ is found to rise slowly with increasing density in these experiments. Comparing these results with earlier (1979) discharges, which showed much lower heating efficiency, the importance of starting with a hot Ohmic plasma and a peaked density profile is striking. On PDX high power injection experiments over a range in plasma current have shown a significant variation with current of both ion heating and total stored plasma energy. Transport analysis of these results indicates that global confinement drops little when I/sup p/ is varied from 480 to 320 kA, but as I/sup p/ falls to 200 kA, tau/sub E/ deteriorates significantly.

Injection system of compact SR light source 'AURORA'

International Nuclear Information System (INIS)

Takayama, Takeshi; Yano, Takashi; Sasaki, Yasushi; Yasumitsu, Naoki

1991-01-01

A half-integer-resonance injection method is introduced for a superconducting SR-ring of 1 m orbit diameter, which is made of a weak focussing single-body magnet. The present method makes it possible to inject an electron beam of an energy of as high as 150 MeV into the ring of a magnetic field strength of 1 T. Several new injection devices are introduced in order to guide the beam under the strong magnetic fringing field, and to excite the half-integer-resonance. The field index of 0.73 is selected for the half-integer-resonance injection. The field index of 0.35 at the maximum magnetic field strength of 4.3 T is to get a sufficiently long quantum lifetime. A new device named resonance jumper is used to pass quickly several resonances of betatron motion without beam loss. The resonances occur when the magnetic field is ramped up and the field index decreases from 0.73 to 0.35. The injection devices except the inflector are air-core magnets in order to work in the strong magnetic field. In November of 1989, the beam was successfully injected and stored. The injection devices and the half-integer-resonance injection method were established. (author)

The beam diagnosis system for ELSA

International Nuclear Information System (INIS)

Schillo, M.

1991-10-01

A beam diagnostic system, which is based on capacitive beam-position monitors combined with fast electronics, has been developed for the Bonn Electron Stretcher Accelerator ELSA. The position signal of each monitor is digitized at an adjustable sampling rate and the most recent 8192 position and intensity values are buffered. This allows a wide range of different beam diagnostic measurements. The main purpose is the closed-orbit correction, which can be carried out on various time scales. To optimize the duty factor of the extracted beam, the system can also be used as a fast relative intensity monitor resolving the intensity distribution of the bunches or of the injected beam. It is designed to support betatron tune and phase measurements with very high accuracy, offering the choice to select any of the beam position monitors. This enables the measuring of many optical parameters. Furthermore any pair of suitable monitors can be used for experimental particle tracking or phase space measurements. (orig.) [de

A beam diagnostic system for ELSA

International Nuclear Information System (INIS)

Schillo, M.; Althoff, K.H.; Drachenfels, W.; Goetz, T.; Husmann, D.; Neckenig, M.; Picard, M.; Schittko, F.J.; Schauerte, W.; Wenzel, J.

1991-01-01

A beam diagnostic system, which is based on capacitive beam-position monitors combined with fast electronics, has been developed for the Bonn ELectron Stretcher Accelerator ELSA. The position signal of each monitor is digitized at an adjustable sampling rate (max.: 10 MHz) and the most recent 8192 position and intensity values are buffered. This allows a wide range of different beam diagnostic measurements. The main purpose is the closed-orbit correction, which can be carried out on various time scales. To optimize the duty factor of the extracted beam, the system can also be used as a fast relative intensity monitor resolving the intensity distribution of the bunches or of the injected beam. It is designed to support betatron tune and phase measurements with very high accuracy, offering the choice to select any of the beam position monitors. This enables the measuring of many optical parameters. Furthermore any pair of suitable monitors can be used for experimental particle tracking or phase space measurements

Neutral Beam Injection for Plasma and Magnetic Field Diagnostics

International Nuclear Information System (INIS)

Vainionpaa, Jaakko Hannes; Leung, Ka Ngo; Kwan, Joe W.; Levinton, Fred

2007-01-01

At the Lawrence Berkeley National Laboratory (LBNL) a diagnostic neutral beam injection system for measuring plasma parameters, flow velocity, and local magnetic field is being developed. High proton fraction and small divergence is essential for diagnostic neutral beams. In our design, a neutral hydrogen beam with an 8 cm x 11 cm (or smaller) elliptical beam spot at 2.5 m from the end of the extraction column is produced. The beam will deliver up to 5 A of hydrogen beam to the target with a pulse width of ∼1 s, once every 1-2 min. The H1+ ion species of the hydrogen beam will be over 90 percent. For this application, we have compared two types of RF driven multicusp ion sources operating at 13.56MHz. The first one is an ion source with an external spiral antenna behind a dielectric RF-window. The second one uses an internal antenna in similar ion source geometry. The source needs to generate uniform plasma over a large (8 cm x 5 cm) extraction area. We expect that the ion source with internal antenna will be more efficient at producing the desired plasma density but might have the issue of limited antenna lifetime, depending on the duty factor. For both approaches there is a need for extra shielding to protect the dielectric materials from the backstreaming electrons. The source walls will be made of insulator material such as quartz that has been observed to generate plasma with higher atomic fraction than sources with metal walls. The ion beam will be extracted and accelerated by a set of grids with slits, thus forming an array of 6 sheet-shaped beamlets. The multiple grid extraction will be optimized using computer simulation programs. Neutralization of the beam will be done in neutralization chamber, which has over 70 percent neutralization efficiency

Transverse beam emittance optimization for the injection into BESSY II

Energy Technology Data Exchange (ETDEWEB)

Kramer, Felix [Helmholtz Zentrum Berlin, Institut Beschleunigerphysik (Germany); Humboldt-Universitaet zu Berlin, Institut fuer Physik (Germany)

2016-07-01

For top up injection into the storage ring BESSY II an average injection efficiency of at least 90% is required. In low alpha mode the injection efficiency does not meet the requirements. Future BESSY II features will include shorter bunches in the storage ring (VSR) and user transparent injection with a non linear kicker. These will raise the demands on the quality of the injected beam even further. This work investigates the development of transverse emittance over the acceleration cycle in the synchrotron and the possibility of transverse emittance exchange by a sequence of skew quadrupoles in the transfer line. Results of emittance measurements and emittance exchange simulations will be given.

High-beta experiments with neutral-beam injection on PDX

International Nuclear Information System (INIS)

Johnson, D.; Bell, M.; Bitter, M.

1983-01-01

Experimental investigations of high-beta plasmas produced in PDX with near-perpendicular neutral-beam injection are reported. Systematic power scans have been performed over a wide range of toroidal fields (νsub(T)q.7 T< Bsub(T)<2.2 T) and plasma currents (200 kA< Isub(p)<500 kA). At high toroidal fields, the change in total stored energy due to beam injection increases linearly with input power and also increases with plasma current. At lower toroidal fields and low injection power levels, the stored energy also increases with power and plasma current. However, at high power and low toroidal fields, a saturation in heating is observed. This result suggests the onset of a νsub(T) limit for circular cross-section tokamaks with near-perpendicular injection. Scaling experiments indicate that this νsub(T) limit increases with rising 1/q. Values of νsub(T)approx.=3% at qsub(PSI)=1.8 have been achieved. At high values of νsub(T)q, short bursts of MHD activity are observed, synchronized with sharply increased fluxes of perpendicular charge-exchange neutrals and rapid decreases in the rate of beam-driven neutron production. When strong bursts occur, there is a significant depletion of the fast-ion population. Estimates of the fast-ion loss indicate that it could explain the observed decrease in heating, although an additional reduction in thermal-plasma confinement cannot be ruled out. Numerical studies using measured pressure profiles predict that the equilibria obtained become unstable to the ideal n=1 internal mode, at about the same value of 0 where the new fluctuations are observed. (author)

Optics Measurements and Matching of TT2-TT10 Line for Injection of the LHC Beam in the SPS

CERN Document Server

Benedetto, E; Guerrero, A; Jacquet, D

2008-01-01

A well matched injection in the SPS is very important for preserving the emittance of the LHC beam. The paper presents the algorithms used for the analysis and the results of the optics measurements done in the transfer line TT2-TT10 and in the SPS. The dispersion is computed by varying the beam momentum and recording the offsets at the BPMs, while the Twiss parameters and emittance measurements in TT2-TT10 are performed with beam profile monitors equipped with OTR screens. These results are completed by those obtained with a matching monitor installed in the SPS as a prototype for the LHC. This device makes use of an OTR screen and a fast acquisition system, to get the turn by turn beam profiles right at injection in the ring, from which the beam mismatch is computed and compared with the results obtained in the line. Finally, on the basis of such measurements, a betatron and dispersion matching of TT2-TT10 for injection in the SPS has been performed and successfully put in operation.

Helical axial injection concept for cyclotrons

Energy Technology Data Exchange (ETDEWEB)

Hudson, E.D.

1981-01-01

A concept for an external beam injection system using a helical beam path centered on the cyclotron axis is described. This system could be used to couple two accelerator stages, with or without intermediate stripping, in cases where conventional axial injection or radial injection are not practical.

Helical axial injection concept for cyclotrons

International Nuclear Information System (INIS)

Hudson, E.D.

1981-01-01

A concept for an external beam injection system using a helical beam path centered on the cyclotron axis is described. This system could be used to couple two accelerator stages, with or without intermediate stripping, in cases where conventional axial injection or radial injection are not practical

Focusing and bunching of ion beam in axial injection channel of IPHC cyclotron TR24

Science.gov (United States)

Adam, T.; Ivanenko, I.; Kazarinov, N.; Osswald, F.; Traykov, E.

2017-07-01

The CYRCe cyclotron (CYclotron pour la ReCherche et l’Enseignement) is used at IPHC (Institut Pluridisciplinaire Hubert Curien) for the production of radio-isotopes for diagnostics, medical treatments and fundamental research in radiobiology. The TR24 cyclotron produced and commercialized by ACSI (Canada) delivers a 16-25 MeV proton beam with intensity from few nA up to 500 μA. The solenoidal focusing instead of existing quadrupole one is proposed in this report. The changing of the focusing elements will give the better beam matching with the acceptance of the spiral inflector of the cyclotron. The parameters of the focusing solenoid are found. Additionally, the main parameters of the bunching system are evaluated in the presence of the beam space charge. This system consists of the buncher installed in the axial injection beam line of the cyclotron. The using of the grid-less multi harmonic buncher may increase the accelerated beam current and will give the opportunity to new proton beam applications.

The SSRL injector beam position monitoring systems

International Nuclear Information System (INIS)

Lavender, W.; Baird, S.; Brennan, S.; Borland, M.; Hettel, R.; Nuhn, H.D.; Ortiz, R.; Safranek, J.; Sebek, J.; Wermelskirchen, C.; Yang, J.

1991-01-01

The beam position monitoring system of the SSRL injector forms a vital component of its operation. Several different types of instrumentation are used to measure the position or intensity of the electron beam in the injector. These include current toroids, fluorescent screens, Faraday cups, the 'Q' meter, a synchrotron light monitor, and electron beam position monitors. This paper focuses on the use of the electron beam position monitors to measure electron trajectories in the injector transport lines and the booster ring. The design of the beam position monitors is described in another paper to be presented at this conference. There are three different beam position monitor systems in the injector. One system consists of a set of five BPMs located on the injection transport line from the linac to the booster (known as the LTB line). There is a second system of six BPMs located on the ejection transport line (known as the BTS line). Finally, there is an array of 40 BPMs installed on the main booster ring itself. This article describes the software and processing electronics of the systems used to measure electron beam trajectories for the new SSRL injector for SPEAR

Design of arc power supply for neutral beam injection system based on super capacitor energy storage

International Nuclear Information System (INIS)

Yang Puqiong; Xuan Weimin; Cao Jianyong; Li Qing; Liu Xiaolong

2015-01-01

The arc power supply is one of the most important equipment for neutral beam injection system. The stability of arc discharge and the quality of ion beam extraction were determined by its performance. For improving stability of the arc discharge, reducing the power network capacity and decreasing impulse on power network, the topology of the arc power supply applied the structure of DC/DC converter based on technology of super capacitor energy storage and switching power supply. Several IGBT power modules are operated in parallel, and it can improve the arc power supply's operating frequency and dynamic response. A filter circuit and a current fast transferring circuit were designed based on a detailed analysis on working process of the arc power sup- ply. According to the requirements and parameters of the arc power supply, and the current response of RL first order circuit, the minimum filter inductances were accurately calculated. Finally, using the model and Matlab, the performance of the arc power supply was simulated and verified, and it meets the design requirement. (authors)

The LEP injection monitors: Design and first results with beam

International Nuclear Information System (INIS)

Burtin, G.; Colchester, R.; Fischer, C.; Halvarsson, B.; Hemery, J.Y.; Jung, R.; Levitt, S.; Vouillot, J.M.

1989-01-01

The LEP injection monitors comprise of split foil monitors, luminescent screens and beam stoppers. The monitors are described with particular emphasis on their special features. These include: their low loss factors, their protection against synchrotron radiation and the screen read-out with a CCD chip. The results obtained during the positron injection tests in LEP in July 1988 are reported. 8 figs

First Experiences of Beam Presence Detection Based on Dedicated Beam Position Monitors

CERN Document Server

Jalal, A; Gasior, M; Todd, B

2011-01-01

High intensity particle beam injection into the LHC is only permitted when a low intensity pilot beam is already circulating in the LHC. This requirement addresses some of the risks associated with high intensity injection, and is enforced by a so-called Beam Presence Flag (BPF) system which is part of the interlock chain between the LHC and its injector complex. For the 2010 LHC run, the detection of the presence of this pilot beam was implemented using the LHC Fast Beam Current Transformer (FBCT) system. However, the primary function of the FBCTs, that is reliable measurement of beam currents, did not allow the BPF system to satisfy all quality requirements of the LHC Machine Protection System (MPS). Safety requirements associated with high intensity injections triggered the development of a dedicated system, based on Beam Position Monitors (BPM). This system was meant to work first in parallel with the FBCT BPF system and eventually replace it. At the end of 2010 and in 2011, this new BP...

New lens system using toroidal magnetic field for intense ion beam

International Nuclear Information System (INIS)

Mohri, Akihiro; Ikuta, Kazunari; Fujita, Junji.

1976-11-01

The use of toroidal magnetic field as a lens system is proposed for producing intense ion beam. The characteristics of the lens system are obtained both analytically and numerically. Some examples of ray-trajectories are presented for different focal lengths. The system is applicable to neutral beam injection heating and micro-pellet implosion for nuclear fusion, and to the other fields such as ion beam X-ray lasers. (auth.)

TFTR neutral beam D-T gas injection system operational experiences of the first two years

International Nuclear Information System (INIS)

Oldaker, M.E.; Lawson, J.E.; Stevenson, T.N.; Kamperschroer, J.H.

1995-01-01

The TFTR Neutral Beam Tritium Gas Injection System (TGIS) has successfully performed tritium operations since December 1993. TGIS operation has been reliable, with no leaks to the secondary containment to date. Notable operational problems include throughput leaks on fill, exit and piezoelectric valves. Repair of a TGIS requires replacement of the assembly, involving TFTR downtime and extensive purging, since the TGIS assembly is highly contaminated with residual tritium, and is located within secondary containment. Modifications to improve reliability and operating range include adjustable reverse bias voltage to the piezoelectric valves, timing and error calculation changes to tune the PLC and hardwired timing control, and exercising piezoelectric valves without actually pulsing gas prior to use after extended inactivity. A pressure sensor failure required the development of an open loop piezoelectric valve drive control scheme, using a simple voltage ramp to partially compensate for declining plenum pressure. Replacement of TGIS's have been performed, maintaining twelve system tritium capability as part of scheduled project maintenance activity

Neutral Beam Injection Requirements and Design Issues for the National Compact Stellarator Experiment

International Nuclear Information System (INIS)

Kugel, H.W.; Neilson, H.; Reiersen, W.; Zarnstorff, M.

2002-01-01

The National Compact Stellarator Experiment (NCSX) will require 6 MW of 50 keV neutral beam injection (NBI) with initial pulse lengths of 500 msec and upgradeable to pulse lengths of 1.5 sec. This paper discusses the NCSX NBI requirements and design issues, and shows how these are provided by the candidate PBX-M [Princeton Beta Experiment-Modification] NBI system

Design of the Injection and extraction system and related machine protection for the Clic Damping Rings

CERN Document Server

Apsimon, Robert; Barnes, Mike; Borburgh, Jan; Goddard, Brennan; Papaphilippou, Yannis; Uythoven, Jan

2014-01-01

Linear machines such as CLIC have relatively low rates of collision between bunches compared to their circular counterparts. In order to achieve the required luminosity, a very small spot size is envisaged at the interaction point, thus a low emittance beam is needed. Damping rings are essential for producing the low emittances needed for the CLIC main beam. It is crucial that the beams are injected and extracted from the damping rings in a stable and repeatable fashion to minimise emittance blow-up and beam jitter at the interaction point; both of these effects will deteriorate the luminosity at the interaction point. In this paper, the parameters and constraints of the injection and extraction systems are considered and the design of these systems is optimised within this parameter space. Related machine protection is considered in order to prevent damage from potential failure modes of the injection and extraction systems.

SPS Injection and Beam Quality for LHC Heavy Ions With 150 ns Kicker Rise Time

CERN Document Server

Goddard, Brennan; Ducimetière, Laurent; Kotzian, Gerd; Uythoven, Jan; Velotti, Francesco

2016-01-01

As part of the LHC Injectors Upgrade project for LHC heavy ions, the SPS injection kicker system rise time needs reduction below its present 225 ns. One technically challenging option under consideration is the addition of fast Pulse Forming Lines in parallel to the existing Pulse Forming Networks for the 12 kicker magnets MKP-S, targeting a system field rise time of 100 ns. An alternative option is to optimise the system to approach the existing individual magnet field rise time (2-98%) of 150 ns. This would still significantly increase the number of colliding bunches in LHC while minimising the cost and effort of the system upgrade. The observed characteristics of the present system are described, compared to the expected system rise time, together with results of simulations and measurements with 175 and 150 ns injection batch spacing. The expected beam quality at injection into LHC is quantified, with the emittance growth and simulated tail population taking into account expected jitter and synchronisatio...

Evidence for neutral beam injected oxygen impurities in 2XIIB

International Nuclear Information System (INIS)

Drake, R.P.; Moos, H.W.

1978-01-01

A series of experiments indicates that the principal source of impurities in the 2XIIB mirror confinement plasma experiment at Lawrence Livermore Laboratory is oxygen in the neutral beams. The dependence of 0 II 539 A emissions on neutral beam current, spatial scans of oxygen emissions, impurity injection experiments, spectral scans of the 0 VI 1032 A line, and other experiments all support this conclusion

Neutral beam current drive with balanced injection

International Nuclear Information System (INIS)

Eckhartt, D.

1990-01-01

Current drive with fast ions has proved its capability to sustain a tokamak plasma free of externally induced electric fields in a stationary state. The suprathermal ion population within the toroidal plasma was created by quasi-tangential and uni-directional injection of high-energy neutral atoms, their ionisation and subsequent deceleration by collisions with the background plasma particles. In future large tokamaks of the NET/INTER-type, with reactor-relevant values of plasma density and temperature, this current drive scheme is expected to maintain the toroidal current at the plasma centre, as current drive by lower hybrid waves will be restricted to the outer plasma regions owing to strong wave damping. Adequate penetration of the neutral atoms through the dense plasma requires particle energies of several hundred kilovolts per nucleon since beam absorption scales roughly with the ratio beam energy over density. The realisation of such high-energy high-power neutral beams, based on negative ion technology, is now under study. (author) 7 refs., 2 figs

The effects of electrode materials on the conversion efficiency of a direct converter used in neutral beam injection systems

International Nuclear Information System (INIS)

Noda, Shunichi; Nagae, Hiroshi; Yano, Hidenobu; Masuda, Mitsuharu; Akazaki, Masanori

1986-01-01

The injection of fast neutral beams into plasmas is thought to be the most promising way for the fusion plasma heating. Fast neutral beams are obtained by injecting fast ions into a neutralizer cell, in which ions are neutralized through charge exchange collisions with the ambient gas. However, the neutralization efficiency in the neutralizer cell is so low that the net power may not be extracted from a fusion reactor unless the energy of the ions being not neutralized in the cell is recovered. The present paper describes some problems associated with the electrostatic direct energy recovery of fast ion beams for this purpose. The titanium and molybdenum were tested as the direct converter electrode materials, and it was found that the conversion efficiency and the conditioning process of the converter electrode depended strongly on the electrode material. The effect of secondary electrons emitted from the electron repeller on the conversion efficiency was also made clear in the present experiments. (author)

160 MeV $H^-$ Injection into the CERN PSB

CERN Document Server

Weterings, W; Borburgh, J; Fowler, T; Gerigk, F; Goddard, B; Hanke, K; Martini, M; Sermeus, L

2007-01-01

The H- beam from the proposed LINAC4 will be injected into the four existing rings of the PS Booster at 160 MeV. A substantial upgrade of the injection region is required, including the modification of the beam distribution system and the construction of a new H- injection system. This paper discusses beam dynamics and hardware requirements and presents the results of optimisation studies of the injection process for different beam characteristics and scenarios. The resulting conceptual design of the injection region is presented, together with the main hardware modifications and performance specifications.

Diamagnetic measurement of JFT-2 plasma heated by neutral beam injection

International Nuclear Information System (INIS)

Maeno, Masaki; Sengoku, Seio; Yamamoto, Shin; Suzuki, Norio; Yamauchi, Toshihiko; Kawashima, Hisato; Miura, Yukitoshi

1984-01-01

A neutral beam was injected into the plasma in the JFT-2 tokamak, and the poloidal beta value βsub(p) of the plasma was determined by a diamagnetic method in which the change in the magnetic flux due to the plasma was obtained by measuring the very small perturbation of the current in the tokamak's toroidal field coil. The ratio of the perturbed to unperturbed currents in the coil was found to be (2-3) x 10 -4 . The poloidal beta value βsub(pd) determined by this method agrees within experimental error with that obtained from magnetic and energy profile analyses. βsub(pd) increases linearly with the total power Psub(net) deposited by the neutral beam in the plasma when Psub(net)=1.5 MW. The heating efficiency of the beam injection heating was found to be lower than that of Joule heating. (author)

Efficient, radiation-hardened, 400- and 800-keV neutral-beam injection systems

International Nuclear Information System (INIS)

Anderson, O.A.; Cooper, W.S.; Fink, J.A.; Goldberg, D.A.; Ruby, L.; Soroka, L.; Tanabe, J.

1983-04-01

We present designs for two negative-ion based neutral beam lines with reactor-level power output. Both beam lines make use of such technologically advanced features as high-current-density surface-conversion ion sources, transverse-field-focussing (TFF) acceleration and transport, and laser photodetachment. For the second of these designs, we also presented detailed beam and vacuum calculations, as well as a brief description of a proof-of-principle test system currently under development

Electron beam injection during active experiments. 1. Electromagnetic wave emissions

International Nuclear Information System (INIS)

Winglee, R.M.; Kellogg, P.J.

1990-01-01

During the active injection of an electron beam, a broad spectrum of waves is generated. In this paper examples of spectra from the recent Echo 7 experiment are presented. These results show that the characteristics of the emissions can change substantially with altitude. Two-dimensional (three velocity) relativistic electromagnetic particle simulations are used to investigate the changes in the plasma conditions required to account for the observed spectral variations. It is shown that many of these variations can be accounted for by assuming that the ratio of the electron plasma frequency ω pe to cyclotron frequency Ω e is less than unity at the lower altitudes of about 200 km and near or above unity at apogee of about 300 km. In the former case, whistlers with a cutoff at ω pe , lower hybrid and plasma waves are driven by the parallel beam energy while electromagnetic fundamental z mode and second harmonic x mode and electrostatic upper hybrid waves are driven by the perpendicular beam energy through the master instability. E x B drifts driven by perpendicular electric fields associated with the beam-plasma interaction can also be important in generating maser emission, particularly for field-aligned injection where there is no intrinsic perpendicular beam energy. The power in the electrostatic waves is a few percent of the beam energy and that in the electromagnetic waves a few tenths of a percent. In the latter case, where ω pe /Ω e increases above unity, emission in the fundamental z mode and second harmonic x mode become suppressed

Numerical simulation of the processes of small-diameter high-current electron beam shaping and injection

CERN Document Server

Gordeev, V S; Myskov, G A

2001-01-01

With the aid of BEAM 25 program there was carried out the numerical simulation of the non-stationary process of shaping a small-diameter (<= 20mm) high-current hollow electron beam in a diode with magnetic insulation,as well as of the process of beam injection into the accelerating LIA track. The diode configuration for the purpose of eliminating the leakage of electron flux to the anode surface was update. Presented are the results of calculation of the injected beam characteristics (amplitude-time parameters of a current pulse, space-angle distributions of electrons etc.) depending on diode geometric parameters.

Beam position monitor system for storage rings

International Nuclear Information System (INIS)

Nakamura, M.; Hinkson, J.A.

1985-05-01

Beam position monitors (BPM) for synchrotron light storage rings usually consist of beam pickup electrodes, coaxial relays and a narrowband receiver. While accurate, these systems are slow and of limited use in the commissioning of an accelerator. A beam position monitor is described which is intended to be a principal diagnostic during debug and routine running of a storage ring. It is capable of measuring the position of a single bunch on the first or nth orbit to an accuracy of a few percent. Stored beam position is more accurately measured with averaging techniques. Beam position changes can be studied in a bandwidth from DC to a few MHz. The beam monitor electronics consist of a separate amplification, detection, and sampling channel for each beam pickup electrode. Fast switches in each channel permit selection of the nth turn for measurement (single bunch mode). A calibration pulse is injected into each channel after beam measurement to permit gain offsets to be measured and removed from the final data. While initially more costly than the usual beam position monitor system, this sytem will pay for itself in reduced storage ring debug and trouble shooting time. 5 refs., 5 figs

Injection locking method for Raman beams in atom interferometer

Science.gov (United States)

Zi, Fei; Deng, Jianing; Zeng, Daji; Li, Tong; Sun, Mingli; Zhang, Xian; Huang, Kaikai; Lu, Xuanhui

2018-03-01

We present a novel method to generate two phase-locked beams with a frequency offset of 6.834 GHz. The output of the master laser is firstly modulated by an electric optical modulator (EOM), and then further injected into an Extended Cavity Diode Lasers (ECDL) which is used to filter out the unwanted mode and amplify the laser power. By locking to the first-order lower sideband of the modulated master laser, the average variance of the phase fluctuations is 5.6 x 10-3 rad2 , which implies phase coherence of 99.44% between the master laser and the slave ECDL. The line width of the beat notes is less than 1Hz. For the long term stability, with the delicate design of the electronic controller in ECDL, the phase coherence of the two laser beams can be stabilized over 200 hours without any adjustment. The Raman system is applicable for gravity detection with a preliminary sensitivity Δg/g of 4.5 x 10-7 for interrogation time of 1500 s.

Neutral Beam Injection Requirements and Design Issues for the National Compact Stellarator Experiment; TOPICAL

International Nuclear Information System (INIS)

H.W. Kugel; H. Neilson; W. Reiersen; M. Zarnstorff

2002-01-01

The National Compact Stellarator Experiment (NCSX) will require 6 MW of 50 keV neutral beam injection (NBI) with initial pulse lengths of 500 msec and upgradeable to pulse lengths of 1.5 sec. This paper discusses the NCSX NBI requirements and design issues, and shows how these are provided by the candidate PBX-M[Princeton Beta Experiment-Modification] NBI system

Beam position measurement system at the Fermilab main accelerator

International Nuclear Information System (INIS)

Kerns, Q.A.

1975-01-01

The beam position system of the Fermilab Main Ring contains one horizontal and one vertical Electrostatic Beam Pickup in each of the 96 cells of the machine. A pair of 75 ohm cables transmits the induced signal from the machine tunnel to the nearest service building. In each of the 24 service buildings, there is a solid-state multiplexer and a beam position detector which processes the A-B signal pairs to produce an intensity-normalized voltage proportional to beam displacement. This voltage is digitized, read into buffer of the Lockheed MAC A, and in turn transferred to the Xerox 530. Horizontal or vertical orbits can be obtained in 50 millisec. Orbits are obtained at injection and at a Main Ring Sample time, if requested, anywhere on the acceleration cycle. Injection orbits can be flattened automatically by a program that sets dipole trim magnets. (auth)

An injection system for a linear accelerator

International Nuclear Information System (INIS)

Santos, A.C.R.

1978-03-01

An injection system for the Linear Accelerator is developed using the parameters of machines at the Centro Brasileiro de Pesquisas Fisicas and the Instituto Militar de Engenharia. The proposed system consists basically of a prebuncher and a chopper. The pre-buncher is used to improve the energy resolution and also to increase the accelerator target current. The chopper is used to remove from the beam the electrons that have no possibility of attaining the desired energy and that are usually lost in the walls and the cavity tube, thus producing undesirable background. Theoretical development of the chopper is performed in order to obtain its dimensions for future construction. The complete design the pre-buncher and its feed supply system and the experimental verication of its performance are also presented. It is intended to give the necessary information for the design and construction of the complete injection system proposed. (Author) [pt

Neutron time behavior for deuterium neutral beam injection into a hydrogen plasma in ORMAK

International Nuclear Information System (INIS)

England, A.C.; Howe, H.C.; Mihalczo, J.T.; Fowler, R.H.

1977-10-01

Neutrons were produced by D-D interactions when a 28-keV deuterium beam was coinjected into a hydrogen plasma in the Oak Ridge Tokamak (ORMAK). Fokker-Planck calculations, which correctly predict the time behavior of the neutron rate after beam turnon, show that the majority of the neutrons are from injected particles interacting with previously injected deuterons that have scattered to pitch angles of approximately 60 to 90 0 while slowing down

EXPERIMENTAL TARGET INJECTION AND TRACKING SYSTEM CONSTRUCTION AND SINGLE SHOT TESTING

International Nuclear Information System (INIS)

PETZOLDT, R.W.; ALEXANDER, N.B.; DRAKE, T.J.; GOODIN, D.T; JONESTRACK, K; VERMILLION, B.A

2003-01-01

Targets must be injected into an IFE power plant at a rate of approximately 5 to 10 Hz. Targets must be tracked very accurately to allow driver beams to be aligned with defined points on the targets with accuracy ± 150 (micro)m for indirect drive and ± 20 (micro)m for direct drive. An experimental target injection and tracking system has been constructed at General Atomics. The injector system will be used as a tool for testing the survivability of various target designs and provide feedback to the target designers. Helium gas propels the targets down an 8 m gun barrel up to 400 m/s. Direct-drive targets are protected in the barrel by sabots that are spring loaded to separate into two halves after acceleration. A sabot deflector directs the sabot halves away from the target injection path. Targets will be optically tracked with laser beams and line-scan cameras. Target position and arrival time will be predicted in real time based on early target position measurements. The system installation will be described. System testing to overcome excessive projectile wear and debris in the gun barrel is presented

The design of a lead-bismuth target system with a dual injection tube

International Nuclear Information System (INIS)

Cho, C.H.; Kim, Y.; Song, T.Y.; Park, W.S.

2005-01-01

A spallation target system is a key component to be developed for an accelerator driven system (ADS). It is known that a 15 ∼ 25 MW spallation target is required for a practical 1000 MWth ADS. The design of a 20 MW spallation target is very challenging because more than 60% of the beam power is deposited as heat in a small volume of the target system. In the present work, a numerical design study was performed to obtain the optimal design parameters for a 20 MW spallation target for a 1000 MW ADS. A dual injection tube was proposed for the reduction of the LBE flow rate at the target channel. The results of the present study show that a 30 cm wide proton beam with a uniform beam distribution should be adopted for the spallation target of a 20 MW power. When the dual LBE injection tube is employed, the LBE flow rate could be reduced by a factor of 4 without reducing the maximum allowable beam current. (authors)

Stripping foils for the PSB H- injection system

CERN Document Server

Aiba, M; Goddard, B; Weterings, W

2009-01-01

Beam physics considerations for the stripping foil of the PSB H- injection system are described, including the arguments for the foil type, thickness, geometry and positioning. The foil performance considerations are described, including expected stripping efficiency, emittance growth, energy straggling, temperature and lifetime. The required movement ranges and tolerances are detailed, together with the assumptions used.

Assessment of the plasma start-up in Wendelstein 7-X with neutral beam injection

International Nuclear Information System (INIS)

Gradic, D.; Dinklage, A.; Brakel, R.; McNeely, P.; Rust, N.; Wolf, R.; Osakabe, M.

2015-01-01

Plasma start-up by neutral beam injection was investigated for stellarators. A zero-dimensional collisional model was extended to evaluate the temporal evolution of the plasma start-up in a confining toroidal magnetic field. Inclusion of different beam energy components indicated a substantial effect due to the energy dependence of beam–gas collisions. Additional collision processes and particle equations were considered to simulate the plasma start-up in helium–hydrogen mixtures. The isotope effect between operation with hydrogen and deuterium beams was also investigated. As a major objective the conditions necessary for a plasma start-up with neutral beams in W7-X have been examined. The assessed beam configuration in W7-X was found not to allow plasma start-up by neutral beam injection alone. The model has been validated for experimental data from W7-AS and Large Helical Device. Quantitative predictions of this study show that the ratio of the beam–plasma interaction length and the plasma volume is an essential quantity for the successful plasma start-up with neutral beams. (paper)

Injection error monitor for KEK 12 GeV PS

International Nuclear Information System (INIS)

Shirakata, Masashi; Sato, Hikaru; Toyama, Takeshi; Marutsuka, Katsumi.

1994-01-01

The injection error monitor is now developing for an easy tuning of the main ring beam injection at the KEK 12 GeV proton synchrotron. The beam trajectory on the horizontal phase space plane is obtained by a test bench system. The injection error monitor proved to be available for the beam injection tuning. (author)

Test facility for the development of 150-keV, multi-megawatt neutral beam systems

International Nuclear Information System (INIS)

Haughian, W.; Baker, W.R.; Biagi, L.A.; Hopkins, D.B.

1975-11-01

The next generation of CTR experiments, such as the Tokamak Fusion Test Reactor (TFTR), will require neutral-beam injection systems that produce multi-megawatt, 120-keV deuterium-beam pulses of 0.5-second duration. Since present injection systems are operating in the 10- to 40-keV range, an intensive development effort is in progress to meet a 150-keV requirement. The vacuum system and power supplies that make up a test facility to be used in the development of these injectors are described

INTERACTION OF NEUTRAL BEAM INJECTED FAST IONS WITH ION CYCLOTRON RESONANCE FREQUENCY WAVES

International Nuclear Information System (INIS)

CHOI, M.; CHAN, V.S.; CHIU, S.C.; OMELCHENKO, Y.A.; SENTOKU, Y.; STJOH, H.E.

2003-01-01

OAK B202 INTERACTION OF NEUTRAL BEAM INJECTED FAST IONS WITH CYCLOTRON RESONANCE FREQUENCY WAVES. Existing tokamaks such as DIII-D and future experiments like ITER employ both NB injection (NBI) and ion-cyclotron resonance heating (ICRH) for auxiliary heating and current drive. The presence of energetic particles produced by NBI can result in absorption of the Ion cyclotron radio frequency (ICRF) power. ICRF can also interact with the energetic beam ions to alter the characteristics of NBI momentum deposition and resultant impact on current drive and plasma rotation. To study the synergism between NBI and ICRF, a simple physical model for the slowing-down of NB injected fast ions is implemented in a Monte-Carlo rf orbit code. This paper presents the first results. The velocity space distributions of energetic ions generated by ICRF and NBI are calculated and compared. The change in mechanical momentum of the beam and an estimate of its impact on the NB-driven current are presented and compared with ONETWO simulation results

UP-GRADED RHIC INJECTION SYSTEM.

Energy Technology Data Exchange (ETDEWEB)

HAHN,H.FISCHER,W.SEMERTZIDIS,Y.K.WARBURTON,D.S.

2003-05-12

The design of the RHIC injection systems anticipated the possibility of filling and operating the rings with a 120 bunch pattern, corresponding to 110 bunches after allowing for the abort gap. Beam measurements during the 2002 run confirmed the possibility, although at the expense of severe transverse emittance growth and thus not on an operational basis. An improvement program was initiated with the goal of reducing the kicker rise time from 110 to {approx}95 ns and of minimizing pulse timing jitter and drift. The major components of the injection system are 4 kicker magnets and Blmlein pulsers using thyratron switches. The kicker terminating resistor and operating voltage was increased to reduce the rise time. Timing has been stabilized by using commercial trigger units and extremely stable dc supplies for the thyratron reservoir. A fiber optical connection between control room and the thyratron trigger unit has been provided, thereby allowing the operator to adjust timing individually for each kicker unit. The changes were successfully implemented for use in the RHIC operation.

Optical two-beam traps in microfluidic systems

DEFF Research Database (Denmark)

Berg-Sørensen, Kirstine

2016-01-01

An attractive solution for optical trapping and stretching by means of two counterpropagating laser beams is to embed waveguides or optical fibers in a microfluidic system. The microfluidic system can be constructed in different materials, ranging from soft polymers that may easily be cast...... written waveguides and in an injection molded polymer chip with grooves for optical fibers. (C) 2016 The Japan Society of Applied Physics....

Electric potential structures and propagation of electron beams injected from a spacecraft into a plasma

International Nuclear Information System (INIS)

Singh, Nagendra; Hwang, K.S.

1988-01-01

The propagation of electron beams injected from a spacecraft into an ambient plasma and the associated potential structures are investigated by one-dimensional Vlasov simulations. For moderate beams, for which the time average spacecraft potential (Φ sa ) lies in the range T e much-lt eΦ sa approx-lt W B , where T e is the electron temperature in energy units and W B is the average beam energy, a double layer forms near the beam head which propagates into the ambient plasma much more slowly than the initial beam velocity. The double layer formation is being reported for the first time. For weak beams, for which |eΦ sa | approx-lt T e , the beam propagates with the initial beam velocity, and no double layer formation occurs. On the other hand, for strong beams for which eΦ sa > W B , the bulk of the beam is returned to the spacecraft, and the main feature of the potential structure is a sheath formation with an intense electric field limited to distances d near the spacecraft surface. These features of the potential structures are compared with those seen in laboratory and space experiments on electron beam injections

The injection system of the stretcher ring ELSA

International Nuclear Information System (INIS)

Dreist, A.

1989-07-01

For the stretcher ring ELSA in the framwork of this thesis an injection system has been concipated and constructed which should allow all projected operational modes of this stretcher ring, the stretcher, the post-acceleration, and the accumulation mode. The proof could be performed that the realized concept allows all these operational modes. Furthermore it could be shown that the injection shifted from the equilibrium orbit has no disadvantageous effects on a uniform extraction and by this on a high touching ratio. In fact it is even possible to apply the decay of the coherent betatron oscillations around the equilibrium orbit, caused by injection of the incident beam shifted from the equilibrium orbit, to diagnosis purposes: By reproduction of this damping process in a simulation model statements on nonlinearities present in the ring and by this statements on the actual phase-space structure are possible. It has so been shown that the concept presented in this thesis and realized for this thesis represents a suited injection system for the stretcher ring ELSA. (orig.) [de

Properties and parameters of the electron beam injected into the mirror magnetic trap of a plasma accelerator

Energy Technology Data Exchange (ETDEWEB)

Andreev, V. V., E-mail: temple18@mail.ru; Novitsky, A. A.; Vinnichenko, L. A.; Umnov, A. M.; Ndong, D. O. [Peoples’ Friendship University of Russia (Russian Federation)

2016-03-15

The parameters of the injector of an axial plasma beam injected into a plasma accelerator operating on the basis of gyroresonance acceleration of electrons in the reverse magnetic field are determined. The trapping of the beam electrons into the regime of gyroresonance acceleration is numerically simulated by the particle- in-cell method. The optimal time of axial injection of the beam into a magnetic mirror trap is determined. The beam parameters satisfying the condition of efficient particle trapping into the gyromagnetic autoresonance regime are found.

Considerations involved in the design of negative-ion-based neutral beam systems

International Nuclear Information System (INIS)

Cooper, W.S.

1983-11-01

We consider the requirements and constraints for negative-ion-based neutral beam injection systems, and show how these are reflected in design considerations. We will attempt to develop a set of guidelines for users and developers to use to see how well (in a qualitative sense, at least) a particular neutral beam system fits a particular proposed need

Design study of electrostatic inflector in compact cyclotron injection system

International Nuclear Information System (INIS)

Zhang Tianjue; Fan Mingwu

1996-01-01

The beam dynamics behaviour in electrostatic inflector is investigated for a vertical type injection system to a compact cyclotron. The computer aided design and matching of the inflector are based on the simulation of computed beam orbit. Modeling and simulation are done on PC-486 to form a software package. The software package can be used to develop a new type cyclotron design combining with the software package CYCCAE developed by China Institute of Atomic Energy three years ago

High heat flux engineering for the upgraded neutral beam injection systems of MAST-U

International Nuclear Information System (INIS)

Dhalla, F.; Mistry, S.; Turner, I.; Barrett, T.R.; Day, I.; McAdams, R.

2015-01-01

Highlights: • A new Residual Ion Dump (RID) and bend magnet system for the upgraded NBI systems have been designed for the 5 s MAST-U pulse requirements. • Design scoping was performed using numerical ion-tracing analysis software (MAGNET and OPERA codes). • A more powerful bending magnet will separate the residual ions into full, half and third energy components. • Three separate CuCrZr dumps spread the power loading resulting in acceptable power footprints. • FE thermo-mechanical analyses using ANSYS to validate the designs against the ITER SDC-IC code. • New bend magnet coils, yoke and CuCrZr water-cooled plates are in the procurement phase. - Abstract: For the initial phase of MAST-U operation the two existing neutral beam injection systems will be used, but must be substantially upgraded to fulfil expected operational requirements. The major elements are the design, manufacture and installation of a bespoke bending magnet and Residual Ion Dump (RID) system. The MAST-design full energy dump is being replaced with new actively-cooled full, half and third energy dumps, designed to receive 2.4 MW of ion power deflected by an iron-cored electromagnet. The main design challenge is limited space available in the vacuum vessel, requiring ion-deflection calculations to ensure acceptable heat flux distribution on the dump panels. This paper presents engineering and physics analysis of the upgraded MAST beamlines and reports the current status of manufacture.

Particle and momentum confinement in tokamak plasmas with unbalanced neutral beam injection and strong rotation

International Nuclear Information System (INIS)

Malik, M.A.

1988-01-01

There is a self-consistent theory of the effects of neutral beam injection on impurity transport in tokamak plasmas. The theory predicts that co-injection drives impurities outward and that counter-injection enhances the normally inward flow of impurities. The theory was applied to carry out a detailed analysis of the large experimental database from the PLT and the ISX-B tokamaks. The theory was found to generally model the experimental data quite well. It is, therefore, concluded that neutral beam co-injection can drive impurities outward to achieve clean central plasmas and a cool radiating edge. Theoretical predictions for future thermonuclear reactors such as INTOR, TIBER II, and ITER indicated that neutral beam driven flow reversal might be an effective impurity control method if the rate of beam momentum deposited per plasma ion is adequate. The external momentum drag, which is a pivotal concept in impurity flow reversal theory, is correctly predicted by the gyroviscous theory of momentum confinement. The theory was applied to analyze experimental data from the PLT and the PDX tokamaks with exact experimental conditions. The theory was found to be in excellent agreement with experiment over a wide range of parameters. It is, therefore, possible to formulate the impurity transport theory from first principles, without resort to empiricism

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

Science.gov (United States)

van Tilborg, Jeroen

2017-10-01

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

Synchronization of RF fields of Indus 2 RF cavities for proper injection and acceleration of beam

International Nuclear Information System (INIS)

Tiwari, Nitesh; Bagduwal, Pritam S.; Lad, M.; Hannurkar, P.R.

2009-01-01

Indus-2 is a synchrotron light source with designed parameters of 2.5 GeV, 300 mA beam current. Four RF cavities fed from four RF power stations have been used for beam acceleration from 550 MeV to 2.5 GeV and synchrotron loss compensation. Particle should reach the RF cavity at the proper phase for proper acceptance of the beam in ring. At injection if the phase is not proper the acceptance efficiency reduces and the maximum stored current in the ring also gets limited. Equal contribution from four cavities at every value of current and energy level is very important. Improper phase will cause the imbalance of the power among different station hence will limit maximum stored current and reduce life time of the stored beam. Phase optimization was done in two-step, first at injection to have better injection rate and the stations were operated at the sufficient power for control loops to operate. Then at 2 GeV and 2.5 GeV energy so that beam extracts equal power from all four RF stations. Phase synchronization of all four cavities from injection to 2.5 GeV has already been done at 50 mA stored beam current. If phases of RF fields inside four RF cavities is not proper then beam will not see the total RF voltage as summation of all four cavity gap voltages, hence it is a very important parameter to be optimized and maintained during operation. (author)

Beam loss reduction by injection painting in the 3-GeV rapid cycling synchrotron of the Japan Proton Accelerator Research Complex

Directory of Open Access Journals (Sweden)

H. Hotchi

2012-04-01

Full Text Available The 3-GeV rapid cycling synchrotron (RCS of the Japan Proton Accelerator Research Complex was commissioned in October 2007. Via the initial beam tuning and a series of underlying beam studies with low-intensity beams, since December 2009, we have intermittently been performing beam tuning experiments with higher-intensity beams including the injection painting technique. By optimizing the injection painting parameters, we have successfully achieved a 420 kW-equivalent output intensity at a low-level intensity loss of less than 1%. Also the corresponding numerical simulation well reproduced the observed painting parameter dependence on the beam loss, and captured a characteristic behavior of the high-intensity beam in the injection painting process. In this paper, we present the experimental results obtained in the course of the RCS beam power ramp-up, especially on the beam loss reduction achieved by employing the injection painting, together with the numerical simulation results.

An IGBT Driven Slotted Beam Pipe Kicker for SPEAR III Injection

International Nuclear Information System (INIS)

2002-01-01

The SPEAR III injection kicker system is composed of three kicker magnets, K1, K2, and K3. These magnets, along with the power modulators to drive them constitute an injection system which will be used to deflect an incoming electron beam with an energy of 3.3 GeV by an angle of 2.5 mrad for K1 and K3, and 1 mrad for K2. The pulse shape of the magnetic field in the three magnets must be matched in order to preserve a closed orbit. The pulse duration is required to be less than 780 ns, with rise and fall times of less than 375 ns, and a pulse repetition frequency of 10 Hz. The aperture of all three magnets is 60 x 34 mm in an 8 inch vacuum vessel. The magnetic length is 1.2 m for K1 and K3, and 0.6 m for K2 [1]. The magnet design employs a slotted beam pipe which is shorted at one end. A solid state IGBT based, induction type of modulator drives the magnets. Modulators for K1 and K3 consist of eight 4.5 kV, 600 A IGBTs, and eight Finemet magnet cores with four 22.5 Ohm output cables to drive 2381 A into the magnets. The modulator for K2 uses four IGBTs and cores, and 8 output cables to produce a 2619 A pulse. Cables of length greater than one half the pulse width must be used in order to avoid reflections from the shorted magnet. The design charge voltage for the modulators is 20 kV for K1 and K3. This paper describes the magnet and modulator design, as and presents test data from a prototype system

Beam Scraping in the SPS for LHC Injection Efficiency and Robustness Studies

CERN Document Server

Letnes, Paul/LPA; Myrheim, Jan

2008-01-01

The Large Hadron Collider (LHC) at CERN will be the world's most powerful accelerator when it is commissioned in fall 2008. Operation of the LHC will require injection of very high intensity beams. Fast transverse beam scrapers have been installed in the Super Proton Synchrotron (SPS) injector to detect and, if necessary, remove transverse beam tails. This will help to both diagnose and prevent beam quenches in the LHC. Scraping of a high intensity beam at top energy can potentially damage the scraper jaws. This has been studied with Monte Carlo simulations to find energy deposition and limits for hardware damage. Loss maps from scraping have been generated both with machine studies and tracking simulations. Time dependent Beam Loss Monitor (BLM) measurements have shown several interesting details about the beam. An analytical model of time dependent losses is compared with beam measurements and demonstrates that beam scraping can be used to estimate the beam size. Energy deposition simulations also give the ...

Feasibility study of an optical resonator for applications in neutral-beam injection systems for the next generation of nuclear fusion reactors

International Nuclear Information System (INIS)

Fiorucci, Donatella

2015-01-01

This work is part of a larger project called SIPHORE (Single gap Photo-neutralizer energy Recovery injector), which aims to enhance the overall efficiency of one of the mechanisms through which the plasma is heated, in a nuclear fusion reactor, i.e. the Neutral Beam Injection (NBI) system. An important component of a NBI system is the neutralizer of high energetic ion beams. SIPHORE proposes to substitute the gas cell neutralizer, used in the current NBI systems, with a photo-neutralizer exploiting the photo-detachment process within Fabry Perot cavities. This mechanism should allow a relevant NBI global efficiency of η≥ 60%, significantly higher than the one currently possible (η≤25% for ITER). The present work concerns the feasibility study of an optical cavity with suitable properties for applications in NBI systems. Within this context, the issue of the determination of an appropriated optical cavity design has been firstly considered and the theoretical and experimental analysis of a particular optical resonator has been carried on. The problems associated with the high levels of intracavity optical power (∼3 MW) required for an adequate photo-neutralization rate have then been faced. In this respect, we addressed both the problem of the thermal effects on the cavity mirrors due to their absorption of intra-cavity optical power (∼1 W) and the one associated to the necessity of a high powerful input laser beam (∼1 kW) to feed the optical resonator. (author)

Computer-controlled data acquisition system for the ISX-B neutral injection system

International Nuclear Information System (INIS)

Edmonds, P.H.; Sherrill, B.; Pearce, J.W.

1980-05-01

A data acquisition system for the Impurity Study Experiment (ISX-B) neutral injection system at the Oak Ridge National Laboratory is presented. The system is based on CAMAC standards and is controlled by a MIK-11/2 microcomputer. The system operates at the ion source high voltage on the source table, transmitting the analyzed data to a terminal at ground potential. This reduces the complexity of the communications link and also allows much flexibility in the diagnostics and eventual control of the beam line

Injection of a relativistic electron beam into neutral hydrogen gas

International Nuclear Information System (INIS)

de Haan, P.H.; Janssen, G.C.A.M.; Hopman, H.J.; Granneman, E.H.A.

1982-01-01

The injection of a relativistic electron beam (0.8 MeV, 6 kA, 150 nsec) into hydrogen gas of 190 Pa pressure results in a plasma with density n/sub e/approx. =10 20 m -3 and temperature kT/sub e/< or approx. =kT/sub i/approx. =3.5 eV. The results of the measurements show good agreement with computations based on a model combining gas ionization and turbulent plasma heating. It is found that a quasistationary state exists in which the energy lost by the beam (about 6% of the total kinetic energy of the beam) is partly used to further ionize and dissociate the gas and for the other part is lost as line radiation

Railgun pellet injection system for fusion experimental devices

International Nuclear Information System (INIS)

Onozuka, M.; Hasegawa, K.

1995-01-01

A railgun pellet injection system has been developed for fusion experimental devices. Using a low electric energy railgun system, hydrogen pellet acceleration tests have been conducted to investigate the application of the electromagnetic railgun system for high speed pellet injection into fusion plasmas. In the system, the pellet is pre-accelerated before railgun acceleration. A laser beam is used to induce plasma armature. The ignited plasma armature is accelerated by an electromagnetic force that accelerates the pellet. Under the same operational conditions, the energy conversion coefficient for the dummy pellets was around 0.4%, while that for the hydrogen pellets was around 0.12%. The highest hydrogen pellet velocity was 1.4 km s -1 using a 1 m long railgun. Based on the findings, it is estimated that the hydrogen pellet has the potential to be accelerated to 5 km s -1 using a 3 m long railgun. (orig.)

The injection and extraction of SSRF booster

International Nuclear Information System (INIS)

Li Yuan; Li Haohu; Liu Guimin; Li Deming

2008-01-01

The layout of injection and extraction system were introduced in this paper. The horizontal and vertical injection acceptance are about 23 πmm·mrad and 37 πmm·mrad, respectively, while emittance of the injected beam is 9 πmm·mrad (3σ). This ensures the high injection efficiency. Three slow kickers can form a good bump. The inside position of the entrance of septum is set to 15 mm, where the bumped beam and the extraction beam are 10 mm and 22 mm, respectively, far from the booster central orbit. (authors)

Ultra-low emittance electron beam generation using ionization injection in a plasma beatwave accelerator

Science.gov (United States)

Schroeder, Carl; Benedetti, Carlo; Esarey, Eric; Leemans, Wim

2017-10-01

Ultra-low emittance beams can be generated using ionization injection of electrons into a wakefield excited by a plasma beatwave accelerator. This all-optical method of electron beam generation uses three laser pulses of different colors. Two long-wavelength laser pulses, with frequency difference equal to the plasma frequency, resonantly drive a plasma wave without fully ionizing a gas. A short-wavelength injection laser pulse (with a small ponderomotive force and large peak electric field), co-propagating and delayed with respect to the beating long-wavelength lasers, ionizes a fraction of the remaining bound electrons at a trapped wake phase, generating an electron beam that is accelerated in the wakefield. Using the beating of long-wavelength pulses to generate the wakefield enables atomically-bound electrons to remain at low ionization potentials, reducing the required amplitude of the ionization pulse, and, hence, the initial transverse momentum and emittance of the injected electrons. An example is presented using two lines of a CO2 laser to form a plasma beatwave accelerator to drive the wake and a frequency-doubled Ti:Al2O3 laser for ionization injection. Supported by the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.

Mode and sawtooth behaviour during neutral beam injection in the W VII-A stellarator

International Nuclear Information System (INIS)

Grieger, G.; Renner, H.; Sapper, J.; Wobig, H.; Dorst, D.; Cattanei, G.; Javel, P.; Rau, F.; Zippe, M.; Jaeckel, H.

1980-02-01

The mode behaviour during Neutral Beam Injection in the WENDELSTEIN VII-A stellarator is presented. The analysis is mainly relying on soft X-ray measurements. Two types of discharges were found during Neutral Beam Injection with plasma currents >= 20 kA. The first type is dominated by large, regular and long sawteeth, which are caused by a (m,n) = (1,1) mode. In the second type the sawteeth disappear completely. Later in the discharge a local disruption causes a transition to the first type; this disruption has a (3,2) mode precursor. A new mode (2,2) is found and phase coupled to the (3,2) mode. Even at a high external rotational transform (t 0 = 0.23) a large (2,1) mode is found after the (3,2) mode has caused the local disruption. At slightly lower external rotational transform values major current disruptions may even occur. This is mainly due to the enhanced edge heating by the Neutral Beam Injection. Results of simulations of the mode structures are also presendet. (orig./GG)

Observation of bifurcation phenomena in an electron beam plasma system

International Nuclear Information System (INIS)

Hayashi, N.; Tanaka, M.; Shinohara, S.; Kawai, Y.

1995-01-01

When an electron beam is injected into a plasma, unstable waves are excited spontaneously near the electron plasma frequency f pe by the electron beam plasma instability. The experiment on subharmonics in an electron beam plasma system was performed with a glow discharge tube. The bifurcation of unstable waves with the electron plasma frequency f pe and 1/2 f pe was observed using a double-plasma device. Furthermore, the period doubling route to chaos around the ion plasma frequency in an electron beam plasma system was reported. However, the physical mechanism of bifurcation phenomena in an electron beam plasma system has not been clarified so far. We have studied nonlinear behaviors of the electron beam plasma instability. It was found that there are some cases: the fundamental unstable waves and subharmonics of 2 period are excited by the electron beam plasma instability, the fundamental unstable waves and subharmonics of 3 period are excited. In this paper, we measured the energy distribution functions of electrons and the dispersion relation of test waves in order to examine the physical mechanism of bifurcation phenomena in an electron beam plasma system

Intense relativistic electron beam injector system for tokamak current drive

International Nuclear Information System (INIS)

Bailey, V.L.; Creedon, J.M.; Ecker, B.M.; Helava, H.I.

1983-01-01

We report experimental and theoretical studies of an intense relativistic electron beam (REB) injection system designed for tokamak current drive experiments. The injection system uses a standard high-voltage pulsed REB generator and a magnetically insulated transmission line (MITL) to drive an REB-accelerating diode in plasma. A series of preliminary experiments has been carried out to test the system by injecting REBs into a test chamber with preformed plasma and applied magnetic field. REBs were accelerated from two types of diodes: a conventional vacuum diode with foil anode, and a plasma diode, i.e., an REB cathode immersed in the plasma. REB current was in the range of 50 to 100 kA and REB particle energy ranged from 0.1 to 1.0 MeV. MITL power density exceeded 10 GW/cm 2 . Performance of the injection system and REB transport properties is documented for plasma densities from 5 x 10 12 to 2 x 10 14 cm -3 . Injection system data are compared with numerical calculations of the performance of the coupled system consisting of the generator, MITL, and diode

Suppression of Alfven Modes on the National Spherical Torus Experiment Upgrade with Outboard Beam Injection [Suppression of Alfven Modes on the NSTX-U with Outboard Beam Injection

International Nuclear Information System (INIS)

Fredrickson, E. D.; Belova, E. V.; Battaglia, D. J.

2017-01-01

In this paper we present data from experiments on the National Spherical Torus Experiment Upgrade, where it is shown for the first time that small amounts of high pitch-angle beam ions can strongly suppress the counterpropagating global Alfven eigenmodes (GAE). GAE have been implicated in the redistribution of fast ions and modification of the electron power balance in previous experiments on NSTX. The ability to predict the stability of Alfven modes, and developing methods to control them, is important for fusion reactors like the International Tokamak Experimental Reactor, which are heated by a large population of nonthermal, super-Alfvenic ions consisting of fusion generated alpha's and beam ions injected for current profile control. We present a qualitative interpretation of these observations using an analytic model of the Doppler-shifted ion-cyclotron resonance drive responsible for GAE instability which has an important dependence on k(perpendicular to rho L). A quantitative analysis of this data with the HYM stability code predicts both the frequencies and instability of the GAE prior to, and suppression of the GAE after the injection of high pitch-angle beam ions.

Fast ion confinement during high power tangential neutral beam injection into low plasma current discharges on the ISX-B tokamak

International Nuclear Information System (INIS)

Carnevali, A.; Scott, S.D.; Neilson, H.; Galloway, M.; Stevens, P.; Thomas, C.E.

1988-01-01

The beam ion thermalization process during tangential neutral beam injection in the ISX-B tokamak is investigated. The classical model is tested in co- and counter-injected discharges at low plasma current, a regime where large orbit width excursions enhance the importance of the loss regions. To test the model, experimental charge exchange spectra are compared with the predictions of an orbit following Monte Carlo code. Measurements of beam-plasma neutron emission and measured decay rates of the emission following beam turnoff provide additional information. Good agreement is found between theory and experiment. Furthermore, beam additivity experiments show that, globally, the confinement of beam ions remains classical, independently of the injected beam power. However, some experimental evidence suggests that the fast ion density in the plasma core did not increase with beam power in a way consistent with classical processes. (author). 35 refs, 17 figs, 3 tabs

Transverse acceptance calculation for continuous ion beam injection into the electron beam ion trap charge breeder of the ReA post-accelerator

Energy Technology Data Exchange (ETDEWEB)

Kittimanapun, K., E-mail: kritsadak@slri.or.th [National Superconducting Cyclotron Laboratory (NSCL), Michigan State University (MSU), 640 S. Shaw Lane, East Lansing, Michigan 48824 (United States); Synchrotron Light Research Institute (SLRI), 111 University Avenue, Muang District, Nakhon Ratchasima, 30000 (Thailand); Baumann, T.M.; Lapierre, A.; Schwarz, S. [National Superconducting Cyclotron Laboratory (NSCL), Michigan State University (MSU), 640 S. Shaw Lane, East Lansing, Michigan 48824 (United States); Bollen, G. [National Superconducting Cyclotron Laboratory (NSCL), Michigan State University (MSU), 640 S. Shaw Lane, East Lansing, Michigan 48824 (United States); Facility for Rare Isotope Beams (FRIB), Michigan State University, 640 S. Shaw Lane, East Lansing, Michigan 48824 (United States)

2015-11-11

The ReA post-accelerator at the National Superconducting Cyclotron Laboratory (NSCL) employs an electron beam ion trap (EBIT) as a charge breeder. A Monte-Carlo simulation code was developed to calculate the transverse acceptance phase space of the EBIT for continuously injected ion beams and to determine the capture efficiency in dependence of the transverse beam emittance. For this purpose, the code records the position and time of changes in charge state of injected ions, leading either to capture or loss of ions. To benchmark and validate the code, calculated capture efficiencies were compared with results from a geometrical model and measurements. The results of the code agree with the experimental findings within a few 10%. The code predicts a maximum total capture efficiency of 50% for EBIT parameters readily achievable and an efficiency of up to 80% for an electron beam current density of 1900 A/cm{sup 2}.

A beam-synchronous gated peak-detector for the LHC beam observation system

CERN Document Server

Levens, T E; Wehrle, U

2013-01-01

Measurements of the bunch peak amplitude using the longitudinal wideband wall-current monitor are a vital tool used in the Large Hadron Collider (LHC) beam observation system. These peak-detected measurements can be used to diagnose bunch shape oscillations, for example coherent quadrupole oscillations, that occur at injection and during beam manipulations. Peak-detected Schottky diagnostics can also be used to obtain the synchrotron frequency distribution and other parameters from a bunched beam under stable conditions. For the LHC a beam-synchronous gated peak detector has been developed to allow individual bunches to be monitored without the influence of other bunches circulating in the machine. The requirement for the observation of both low intensity pilot bunches and high intensity bunches for physics requires a detector front-end with a high bandwidth and a large dynamic range while the usage for Schottky measurements requires low noise electronics. This paper will present the design of this detector s...

Buildup of electrons with hot electron beam injection into a homogeneous magnetic field

International Nuclear Information System (INIS)

Bashko, V.A.; Krivoruchko, A.M.; Tarasov, I.K.

1989-01-01

The injection of the monoenergetic beam of electrons into the vacuum drift channel under the conditions when the beam current exceeds a certain threshold value involves a virtual cathode creation. The process of virtual cathode creation leads to an exchange of one-fluid movement of beam particles to three-fluid one corresponding to incident, reflected and passed through anticathode beam particles. For the monoenergetic beam case when the velocity spread Δv dr (v dr is the beam drift velocity), the beam instability was predicted in theory and was observed in experiment. Meanwhile, the injection in the drift space of the 'hot' beam having finite spread in velocities may be accompanied not only by the reflection of particles if their velocity v 1/2 (where φ is the electrostatic potential dip value, e and m are the electron charge and mass, respectively), but also the mutual Coulomb scattering of incident and reflected electrons. The scattering process leads in its turn to appearance of viscosity forces and to trapping of a part of beam electrons into the effective potential well formed by electrostatic potential dip and the viscous force potential. The interaction of travelling and trapped particles may occur even at the stage preceding the virtual electrode formation and it may influence the process of its appearance and also the current flow through the drift space. In this report there are described the experimental results on accumulation of electrons when electron beam propagates in vacuum and has a large spread in particle velocities Δv dr in the homogeneous longitudinal magnetic field when ω pe He where ω pe is the electron Langmuir frequency of beam electrons, ω He is the electron cyclotron frequency. (author) 6 refs., 2 figs

Railgun pellet injection system for fusion experimental devices

Energy Technology Data Exchange (ETDEWEB)

Onozuka, M. [Mitsubishi Heavy Industries Ltd., Yokohama (Japan). Adv. Tech. Dev. Dept.; Oda, Y. [Mitsubishi Heavy Industries Ltd., Yokohama (Japan). Adv. Tech. Dev. Dept.; Azuma, K. [Mitsubishi Heavy Industries Ltd., Yokohama (Japan). Adv. Tech. Dev. Dept.; Satake, K. [Mitsubishi Heavy Industries Ltd., Yokohama (Japan). Adv. Tech. Dev. Dept.; Kasai, S. [Japan Atomic Energy Research Institute, Tokai-mura, Naka-gun 319-11 (Japan); Hasegawa, K. [Japan Atomic Energy Research Institute, Tokai-mura, Naka-gun 319-11 (Japan)

1995-11-01

A railgun pellet injection system has been developed for fusion experimental devices. Using a low electric energy railgun system, hydrogen pellet acceleration tests have been conducted to investigate the application of the electromagnetic railgun system for high speed pellet injection into fusion plasmas. In the system, the pellet is pre-accelerated before railgun acceleration. A laser beam is used to induce plasma armature. The ignited plasma armature is accelerated by an electromagnetic force that accelerates the pellet. Under the same operational conditions, the energy conversion coefficient for the dummy pellets was around 0.4%, while that for the hydrogen pellets was around 0.12%. The highest hydrogen pellet velocity was 1.4 km s{sup -1} using a 1 m long railgun. Based on the findings, it is estimated that the hydrogen pellet has the potential to be accelerated to 5 km s{sup -1} using a 3 m long railgun. (orig.).

A comparison of L-band and C-band rf guns as sources for inline-injection systems

International Nuclear Information System (INIS)

Gallardo, J.C.; Kirk, H.G.; Meyerer, T.

1994-12-01

We consider the beam dynamics associated with installing a BNL type 1 1/2 cell L-band or C-band rf gun before two TESLA L-band cryomodules. This system will deliver a 25 MeV electron beam with peak currents on the order of 100 A suitable for further magnetic compression. evaluate the injection systems utilizing the electron beam dynamic code PARMELA from the point of view of minimizing the transverse invariant emittance

Fabrication and installment of hard-wired I and C works for the neutral beam injection system of the KSTAR project

International Nuclear Information System (INIS)

Jung, Ki Sok; Oh, Byung Hun; In, Sang Ryul; Yoon, Jae Sung

2004-01-01

Instrumentation and Control(I and C) of the neutral beam injection(NBI) system for the K-STAR national fusion research project has been working from the start of the project to answer diverse requests arising from various facets of the development and construction phases of the project. In a parallel effort with the software oriented I and C development, there has been existing an enormous amount of hard-wiring I and C works for the NBI facility to be developed and fabricated in schedule. Circuits and hardwired functions have been designed, tested, fabricated, and finally installed to the relevant parts of the system. Some examples of those hard-wired I and C works are related to the vacuum system, gas feeding system, arc detector circuit, ion source monitoring, bending magnet and calorimeter. They are one of those integral parts for the proper operation of the NBI system. Examples of those hard-wired I and C works are introduced in this presentation

The direct injection of intense ion beams from a high field electron cyclotron resonance ion source into a radio frequency quadrupole.

Science.gov (United States)

Rodrigues, G; Becker, R; Hamm, R W; Baskaran, R; Kanjilal, D; Roy, A

2014-02-01

The ion current achievable from high intensity ECR sources for highly charged ions is limited by the high space charge. This makes classical extraction systems for the transport and subsequent matching to a radio frequency quadrupole (RFQ) accelerator less efficient. The direct plasma injection (DPI) method developed originally for the laser ion source avoids these problems and uses the combined focusing of the gap between the ion source and the RFQ vanes (or rods) and the focusing of the rf fields from the RFQ penetrating into this gap. For high performance ECR sources that use superconducting solenoids, the stray magnetic field of the source in addition to the DPI scheme provides focusing against the space charge blow-up of the beam. A combined extraction/matching system has been designed for a high performance ECR ion source injecting into an RFQ, allowing a total beam current of 10 mA from the ion source for the production of highly charged (238)U(40+) (1.33 mA) to be injected at an ion source voltage of 60 kV. In this design, the features of IGUN have been used to take into account the rf-focusing of an RFQ channel (without modulation), the electrostatic field between ion source extraction and the RFQ vanes, the magnetic stray field of the ECR superconducting solenoid, and the defocusing space charge of an ion beam. The stray magnetic field is shown to be critical in the case of a matched beam.

The direct injection of intense ion beams from a high field electron cyclotron resonance ion source into a radio frequency quadrupole

Science.gov (United States)

Rodrigues, G.; Becker, R.; Hamm, R. W.; Baskaran, R.; Kanjilal, D.; Roy, A.

2014-02-01

The ion current achievable from high intensity ECR sources for highly charged ions is limited by the high space charge. This makes classical extraction systems for the transport and subsequent matching to a radio frequency quadrupole (RFQ) accelerator less efficient. The direct plasma injection (DPI) method developed originally for the laser ion source avoids these problems and uses the combined focusing of the gap between the ion source and the RFQ vanes (or rods) and the focusing of the rf fields from the RFQ penetrating into this gap. For high performance ECR sources that use superconducting solenoids, the stray magnetic field of the source in addition to the DPI scheme provides focusing against the space charge blow-up of the beam. A combined extraction/matching system has been designed for a high performance ECR ion source injecting into an RFQ, allowing a total beam current of 10 mA from the ion source for the production of highly charged 238U40+ (1.33 mA) to be injected at an ion source voltage of 60 kV. In this design, the features of IGUN have been used to take into account the rf-focusing of an RFQ channel (without modulation), the electrostatic field between ion source extraction and the RFQ vanes, the magnetic stray field of the ECR superconducting solenoid, and the defocusing space charge of an ion beam. The stray magnetic field is shown to be critical in the case of a matched beam.

Transmission of the Neutral Beam Heating Beams at TJ-II

International Nuclear Information System (INIS)

Fuentes Lopez, C.

2007-01-01

Neutral beam injection heating has been development for the TJ-II stellarator. The beam has a port-through power between 700-1500 kW and injection energy 40 keV. The sensibility of the injection system to the changes of several parameters is analysed. Beam transmission is limited by losses processes since beam is born into the ions source until is coming into the fusion machine. For the beam transmission optimization several beam diagnostics have been developed. A carbon fiber composite (CFC) target calorimeter has been installed at TJ-II to study in situ the power density distribution of the neutral beams. The thermographic print of the beam can be recorded and analysed in a reliable way due to the highly anisotropic thermal conductivity of the target material. With the combined thermographic and calorimetric measurements it has been possible to determine the power density distribution of the beam. It has been found that a large beam halo is present, which can be explained by the extreme misalignment of the grids. This kind of halo has a deleterious effect on beam transport and must be minimized in order to improve the plasma heating capability of the beams. (Author) 155 refs

Mu2e-II Injection from PIP-II

Energy Technology Data Exchange (ETDEWEB)

Neuffer, David [Fermilab

2018-04-26

We discuss injection of 800 MeV proton beam from PIP-II into the production target for Mu2e-II, assuming a targeting and μ production scenario similar to mu2e. The incoming beam trajectory must be modified from the mu2e parameters to match the focusing fields. Adding a vertical deflection at injection enables the injected beam to reach the target. Other differences from the mu2e system must be considered, including changes in the target structure, the radiation shielding and beam dump/absorber. H- beam should be stripped to p+. Other variations are discussed.

Design of kicker magnet and power supply unit for synchrotron beam injection

International Nuclear Information System (INIS)

Wang, Ju.

1991-03-01

To inject beams from the positron accumulator ring (PAR) into the synchrotron, a pulsed kicker magnet is used. The specifications of this kicker magnet and the power supply unit are listed and discussed in this report

An improved 8 GeV beam transport system for the Fermi National Accelerator Laboratory

International Nuclear Information System (INIS)

Syphers, M.J.

1987-06-01

A new 8 GeV beam transport system between the Booster and Main Ring synchrotrons at the Fermi National Accelerator Laboratory is presented. The system was developed in an effort to improve the transverse phase space area occupied by the proton beam upon injection into the Main Ring accelerator. Problems with the original system are described and general methods of beamline design are formulated. Errors in the transverse properties of a beamline at the injection point of the second synchrotron and their effects on the region in transverse phase space occupied by a beam of particles are discussed. Results from the commissioning phase of the project are presented as well as measurements of the degree of phase space dilution generated by the transfer of 8 GeV protons from the Booster synchrotron to the Main Ring synchrotron

The beam diagnosis system for ELSA. Das Strahldiagnosesystem fuer ELSA

Energy Technology Data Exchange (ETDEWEB)

Schillo, M.

1991-10-01

A beam diagnostic system, which is based on capacitive beam-position monitors combined with fast electronics, has been developed for the Bonn Electron Stretcher Accelerator ELSA. The position signal of each monitor is digitized at an adjustable sampling rate and the most recent 8192 position and intensity values are buffered. This allows a wide range of different beam diagnostic measurements. The main purpose is the closed-orbit correction, which can be carried out on various time scales. To optimize the duty factor of the extracted beam, the system can also be used as a fast relative intensity monitor resolving the intensity distribution of the bunches or of the injected beam. It is designed to support betatron tune and phase measurements with very high accuracy, offering the choice to select any of the beam position monitors. This enables the measuring of many optical parameters. Furthermore any pair of suitable monitors can be used for experimental particle tracking or phase space measurements. (orig.).

Injection Protection Upgrade for the HL-LHC

CERN Document Server

AUTHOR|(CDS)2067108; Biancacci, Nicolo; Bracco, Chiara; Frasciello, Oscar; Gentini, Luca; Goddard, Brennan; Lechner, Anton; Maciariello, Fausto; Perillo Marcone, Antonio; Salvant, Benoit; Shetty, Nikhil Vittal; Steele, Genevieve; Velotti, Francesco; Zobov, Mikhail

2015-01-01

The injector complex of the LHC is undergoing important changes in the light of the LIU project to provide brighter beams to the LHC. For this reason and as part of the High Luminosity LHC project the injection protection system of the LHC will be upgraded in the Long Shutdown 2 (2018 - 2019) to be able to protect downstream elements against injection failures with the high brightness, high intensity HL-LHC beams. The upgraded LHC injection protection system will consist of a segmented injection protection absorber TDIS, and auxiliary collimators and masks. The layout modifications are described, and the machine element protection and absorber jaw robustness studies are presented for the new systems.

Low energy, high power injection in JT-60 NBI

International Nuclear Information System (INIS)

Mizuno, Makoto; Dairaku, Masayuki; Horiike, Hiroshi

1988-05-01

JT-60 neutral beam injector (JT-60 NBI) is designed to inject 20 MW neutral hydrogen beam at energies of 70 ∼ 100 keV and the injection power decreases significantly at low energies (∼40 keV). For the extention of operation region aiming at the low density plasma heating and achieving H-mode by plasma periphery heating, increment of the injection power at low beam energies was required. The single-stage acceleration system was investigated in advance at the Prototype Injector Unit. From this result, the total injection power of 17 MW at 40 keV, 48 A per source was expected at the JT-60 NBI. This system was adopted in the JT-60 NBI from June, 1987 to July, 1987 and 17.6 MW neutral beam injection power was achieved. In the NB heating experiment, the H-mode transition phenomena was observed in JT-60 plasma. (author)

Calculation of beam injection and modes of acceleration for the JINR phasotron

International Nuclear Information System (INIS)

Vorozhtsov, S.B.; Dmitrievsky, V.P.

1981-01-01

On the basis of computer simulation of particles motion from the injection region up to the final radius of the accelerated proton beam behaviour together with different modes of the JINR high current synchrocyclotron operation is investigated. The THOUR modified computer code is used for calculations. The calculations have been performed with allowance for particle radial-phase motion and particle axial motion and although with beam collective effects. Beam dynamics during first turns of particles has been considered by integrating equations of motion. Tolerances for magnetic field structure in the region of first phase oscillation are obtained. Verifications of time dependences of accelerated voltage amplitude are performed. Time dependences of beam intensity (with and without account for space charge effect) and of mean magnetic field disturbance and the dependence of the separatrice dimension on the orbit radius of the accelerated beam are given. The conclusion is drawn on the correctness of the earlier appreciation of beam intensity equaling 40-45 mkA

Cluster beam injection

International Nuclear Information System (INIS)

Bottiglioni, F.; Coutant, J.; Fois, M.

1978-01-01

Areas of possible applications of cluster injection are discussed. The deposition inside the plasma of molecules, issued from the dissociation of the injected clusters, has been computed. Some empirical scaling laws for the penetration are given

First experiences of beam presence detection based on dedicated beam position monitors

International Nuclear Information System (INIS)

Jalal, A.; Gabourin, S.; Gasior, M.; Todd, B.

2012-01-01

High intensity particle beam injection into the LHC is only permitted when a low intensity pilot beam is already circulating in the LHC. This requirement addresses some of the risks associated with high intensity injection, and is enforced by a so-called Beam Presence Flag (BPF) system which is part of the interlock chain between the LHC and its injector complex. For the 2010 LHC run, the detection of the presence of this pilot beam was implemented using the LHC Fast Beam Current Transformer (FBCT) system. However, the primary function of the FBCTs, that is reliable measurement of beam currents, did not allow the BPF system to satisfy all quality requirements of the LHC Machine Protection System (MPS). Safety requirements associated with high intensity injections triggered the development of a dedicated system, based on Beam Position Monitors (BPM). This system was meant to work first in parallel with the FBCT BPF system and eventually replace it. At the end of 2010 and in 2011, this new BPF implementation based on BPMs was designed, built, tested and deployed. This paper reviews both the FBCT and BPM implementation of the BPF system, outlining the changes during the transition period. The paper briefly describes the testing methods, focuses on the results obtained from the tests performed during the end of 2010 LHC run and shows the changes made for the BPM BPF system deployment in LHC in 2011. Whilst the system has been proved to work with a threshold of 6*10 8 charges, it has been implemented with a threshold of 2*10 9 charges to protect the LHC. (authors)

High performance experiments on high pressure supersonic molecular beam injection in the HL-1M tokamak

International Nuclear Information System (INIS)

Yao Lianghua; Dong Jiafu; Zhou Yan; Feng Beibing; Cao Jianyong; Li Wei; Feng Zhen; Zhang Jiquan; Hong Wenyu; Cui Zhengying; Wang Enyao; Liu Yong

2004-01-01

Supersonic molecular beam injection (SMBI) was first proposed and demonstrated on the HL-1 tokamak and was successfully developed and used on HL-1M. Recently, new results of SMBI experiments were obtained by increasing the gas pressure from 0.5 to over 1.0 MPa. A stair-shaped density increment was obtained with high-pressure multi-pulse SMBI that was similar to the density evolution behaviour during multi-pellet injection. This demonstrated the effectiveness of SMBI as a promising fuelling tool for steady-state operation. The penetration depth and injection speed of the high-pressure SMBI were roughly measured from the contour plot of the Hα emission intensity. It was shown that injected particles could penetrate into the core region of the plasma. The penetration speed of high-pressure SMBI particles in the plasma was estimated to be about 1200 m s -1 . In addition, clusters within the beam may play an important role in the deeper injection. (author)

The principles of designing autoregulated circuits of particles injection in synchrotron accelerators

International Nuclear Information System (INIS)

Karabekov, I.P.; Krol', V.K.

1974-01-01

The paper deals with an investigation of beam injection systems of large electron synchrotrons from the point of view of a possibility of the injection process automation. The injection system elements of the Erevan synchrotron are considered as an example to show the possibility of designing a closed automatic control system based on the beam parameter data. To obtain data on the beam parameters a scheme based on magnetoinduction zero-indicators is used. The particle capture int orbit and automatic control system is shown to be indeterminate without preliminary monochromatization of the beam. The automatic control functional scheme is presented and main technical requirements for some synchrotron components are formulated. The realization of the proposed automatic control system on the Erevan synchrotron will ensure the matching of beam trajectory parameters at the point of particle capture into orbit with injected particle energy and the injection field value on the orbit, if the accuracy required for the adjustment of the magnetic field parameters necessary for the first turns is achieved

Electron beam injection and associated phenomena as observed in a large space simulation chamber

International Nuclear Information System (INIS)

Beghin, C.; Arnal, Y.; Delahaye, J.Y.

1982-01-01

This chapter describes an experiment whose main purpose was to perform a simulation under conditions where the ambient neutral and ionized gas, magnetic field strength and lay-out of the different packages were as close as possible to those anticipated for the First Spacelab Flight (FSLP) mission. Phenomena Induced by Charged Particle Beams (PICPAB) are planned to be investigated during the FSLP using a Euopean payload. The PICPAB experiment consists of two accelerators of electron and ion beams and associated diagnostic instruments including wave receivers, thermal plasma probes and return current particle energy-analyzers. The main results of the test with the electron beam are reported. Topics considered include the experimental configuration; a transverse dc electric field in the absence of background plasma; a transverse dc electric field in the background plasma; ambient plasma response; a high-frequency electric field; return current characteristics; and collector vs. plasma behavior. The complexity of the beam-plasma-collector-gun system is shown where nonlinear processes are generated in several consecutive steps. It is concluded that under the peculiar conditions described (with the beam propagation distance shorter than the first node focalization length and nearly zero pitch-angle injection, neutral gas pressure ranging from less to 10 -6 up to 10 -4 torr), the beam plasma discharge was never triggered

Beam interaction of a pulsed, nonlinear in-vacuum injection magnet

International Nuclear Information System (INIS)

Rast, Helge

2013-01-01

Theme of this thesis is the study of the interaction of the injection magnet designed for BESSY II with the electron beam. The main topic of this thesis lies in the numerical and measurement-technical study of the loss factor, the wake potential, and the wake impedance of the nonlinear kicker magnet with the aim of an optimization of the magnet design, so that a stable operation of the kicker in the BESSY II storage ring is made possible. A further main topic of this thesis is a study on the matching of the injection scheme with a single kicker to the conditions of the DELTA storage ring, which is operated by the TU Dortmund.

The Impact of Beam Deposition on Bootstrap Current of Fast Ion Produced by Neutral Beam Tangential Injection

International Nuclear Information System (INIS)

Huang Qian-Hong; Gong Xue-Yu; Lu Xing-Qiang; Yu Jun; Cao Jin-Jia

2015-01-01

The density profile of fast ions arising from a tangentially injected diffuse neutral beam in tokamak plasma is calculated. The effects of mean free paths and beam tangency radius on the density profile are discussed under typical HL-2A plasmas parameters. The results show that the profile of fast ions is strongly peaked at the center of the plasma when the mean free path at the maximum deuteron density is larger than the minor radius, while the peak value decreases when the mean free path at the maximum deuteron density is larger than twice that of the minor radius due to the beam transmission loss. Moreover, the bootstrap current of fast ions for various mean free paths at the maximum deuteron density is calculated and its density is proved to be closely related to the deposition of the neutral beam. With the electron return current considered, the net current density obviously decreases. Meanwhile, the peak central fast ion density increases when the beam tangency radius approaches the major radius, and the net bootstrap current increases rapidly with the increasing beam tangency radius. (paper)

The direct injection of intense ion beams from a high field electron cyclotron resonance ion source into a radio frequency quadrupole

Energy Technology Data Exchange (ETDEWEB)

Rodrigues, G., E-mail: gerosro@gmail.com; Kanjilal, D.; Roy, A. [Inter University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi (India); Becker, R. [Institut fur Angewandte Physik der Universitaet, D-60054 Frankfurt/M (Germany); Hamm, R. W. [R and M Technical Enterprises, Inc., 4725 Arlene Place, Pleasanton, California 94566 (United States); Baskaran, R. [Indira Gandhi Centre for Atomic Research, Kalpakkam, Tamilnadu (India)

2014-02-15

The ion current achievable from high intensity ECR sources for highly charged ions is limited by the high space charge. This makes classical extraction systems for the transport and subsequent matching to a radio frequency quadrupole (RFQ) accelerator less efficient. The direct plasma injection (DPI) method developed originally for the laser ion source avoids these problems and uses the combined focusing of the gap between the ion source and the RFQ vanes (or rods) and the focusing of the rf fields from the RFQ penetrating into this gap. For high performance ECR sources that use superconducting solenoids, the stray magnetic field of the source in addition to the DPI scheme provides focusing against the space charge blow-up of the beam. A combined extraction/matching system has been designed for a high performance ECR ion source injecting into an RFQ, allowing a total beam current of 10 mA from the ion source for the production of highly charged {sup 238}U{sup 40+} (1.33 mA) to be injected at an ion source voltage of 60 kV. In this design, the features of IGUN have been used to take into account the rf-focusing of an RFQ channel (without modulation), the electrostatic field between ion source extraction and the RFQ vanes, the magnetic stray field of the ECR superconducting solenoid, and the defocusing space charge of an ion beam. The stray magnetic field is shown to be critical in the case of a matched beam.

Safe LHC beam commissioning

International Nuclear Information System (INIS)

Uythoven, J.; Schmidt, R.

2007-01-01

Due to the large amount of energy stored in magnets and beams, safety operation of the LHC is essential. The commissioning of the LHC machine protection system will be an integral part of the general LHC commissioning program. A brief overview of the LHC Machine Protection System will be given, identifying the main components: the Beam Interlock System, the Beam Dumping System, the Collimation System, the Beam Loss Monitoring System and the Quench Protection System. An outline is given of the commissioning strategy of these systems during the different commissioning phases of the LHC: without beam, injection and the different phases with stored beam depending on beam intensity and energy. (author)

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

International Nuclear Information System (INIS)

Lebedev, V.A.

1993-01-01

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

Realistic RF system and Beam Simulation in Real Time for a Synchrotron

CERN Document Server

Tückmantel, Joachim

2001-01-01

Due to heavy beam loading with gaps in the LHC beams, RF and beam are intimately linked to a complex system with fast transients where the RF loops and their limitations play a decisive role. Such a system is difficult to assess with analytical methods. To learn about overall system stability and for the definition of RF components to be built it is essential to understand the complete system long before the machine really exists. Therefore the author has written a general purpose real time simulation program and applied it to model the LHC machine with its beam pattern and complete double RF system. The latter is equipped with fast RF vector feedback loops having loop delay, transmitter power limitation and limited amplifier bandwidth as well as including one-turn-delay feedback and longitudinal batch injection damping. The development of all RF and beam quantities can be displayed graphically turn by turn. These frames can be assembled to a realistic multi-trace scope movie.

Fast ion behavior during neutral beam injection in ATF

International Nuclear Information System (INIS)

Wade, M.R.; Thomas, C.E.; Colchin, R.J.; Rome, J.A.; England, A.C.; Fowler, R.H.; Aceto, S.C.

1993-01-01

In stellarators, single-particle confinement properties can be more complex than in their tokamak counterparts. Fast-ion behavior in tokamaks has been well characterized through an abundance of measurements on various devices and in general has been shown to be consistent with classical slowing-down theory, although anomalous ion behavior has been observed during intense beam injection in ISX-B, during fishbone instabilities in PDX, and in experiments on TFR. In contrast, fast ion behavior in stellarators is not as wel established experimentally with the primary experiments to date focusing o near-perpendicular or perpendicular neutral beam injection (NBI) on the Wendelstein 7-A stellarator (91 and Heliotron-E. This paper addresses fast-ion confinement properties in a large-aspect-ratio, moderate-shear stellarator, the Advanced Toroidal Facility, during tangential NBI. The primary data used in this study are the experimentally measured energy spectra of charge-exchange neutrals escaping from the plasma, using a two-dimensional scanning neutral particle analyzer. This diagnostic method is well established, having been used on several devices since the early 1970's. Various aspects of fast-ion behavior are investigated by comparing these data with computed theoretical spectra based on energeticion distributions derived from the fastion Fokker-Planck equation. Ion orbits are studied by computer orbit following, by the computation of J* surfaces, and by Monte Carlo calculations

Multiple track Doppler-shift spectroscopy system for TFTR neutral beam injectors

International Nuclear Information System (INIS)

Kamperschroer, J.H.; Kugel, H.W.; Reale, M.A.

1986-09-01

A Doppler-shift spectroscopy system has been installed on the TFTR neutral beam injection system to measure species composition during both conditioning and injection pulses. Two intensified vidicon detectors and two spectrometers are utilized in a system capable of resolving data from up to twelve ion sources simultaneously. By imaging the light from six ion sources onto one detector, a cost-effective system has been achieved. Fiber optics are used to locate the diagnostic in an area remote from the hazards of the tokamak test cell allowing continuous access, and eliminating the need for radiation shielding of electronic components. Automatic hardware arming and interactive data analysis allow beam composition to be computed between tokamak shots for use in analyzing plasma heating experiments. Measurements have been made using lines of sight into both the neutralizer and the drift duct. Analysis of the data from the drift duct is both simpler and more accurate since only neutral particles are present in the beam at this location. Comparison of the data taken at these two locations reveals the presence of partially accelerated particles possessing an estimated 1/e half-angle divergence of 15 0 and accounting for up to 30% of the extracted power

Conjugate echoes of artifically injected electron beams detected optically by means of new image processing

International Nuclear Information System (INIS)

Hallinan, T.J.; Stenbaek-Nielsen, H.C.; Baldridge, J.; Winckler, J.; Malcolm, P.

1990-01-01

Following two upward injections of energetic electrons (38 keV and 26 keV) from the Echo 4 rocket-borne electron accelerator, artificial auroral streaks were detected by ground-based low-light-level television. They were delayed relative to the injections by 2.06 s and 2.42 s, respectively. The delays are only 4-5% longer than calculated using a dynamic model of the geomagnetic field. Other field models yielded shorter bounce times. Since the delays were in the inverse ratio of the relativistic velocities calculated for the nominal beam energies, it is concluded that the potential of the payload remained below 1 kV during 45 mA injections at an altitude of 210 km. The echo streaks showed little dispersion in either time or space, indicating that the portion of the beam returning to the northen hemisphere loss cone remained collimated and nearly monoenergetic. But there was a 70% loss in the return flux. A diligent search failed to locate similar echoes from the more powerful injections employed in the Echo 5 and Echo 7 rocket experiments, suggesting flux losses of at least 98% and 92%, respectively. The losses are thought to be due to pitch angle scattering out of the loss cone as the electrons traverse the equatorial region but could also be due to collective beam plasma interactions

The drive beam pulse compression system for the CLIC RF power source

CERN Document Server

Corsini, R

1999-01-01

The Compact LInear Collider (CLIC) is a high energy (0.5 to 5 TeV) e ± linear collider that uses a high- current electron beam (the drive beam) for 30 GHz RF power production by the Two-Beam Acceleration (TBA) method. Recently, a new cost­effective and efficient generation scheme for the drive beam has been developed. A fully­loaded normal­conducting linac operating at lower frequency (937 MHz) generates and accelerates the drive beam bunches, and a compression system composed of a delay­line and two combiner rings produces the proper drive beam time structure for RF power generation in the drive beam decelerator. In this paper, a preliminary design of the whole compression system is presented. In particular, the fundamental issue of preserving the bunch quality along the complex is studied and its impact on the beam parameters and on the various system components is assessed. A first design of the rings and delay­line lattice, including path length tuning chicanes, injection and extraction regions is a...

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

CERN Document Server

Papotti, G; Follin, F; Wehrle, U

2011-01-01

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

Pulse radiolysis based on a femtosecond electron beam and a femtosecond laser light with double-pulse injection technique

International Nuclear Information System (INIS)

Yang Jinfeng; Kondoh, Takafumi; Kozawa, Takahiro; Yoshida, Youichi; Tagawa, Seiichi

2006-01-01

A new pulse radiolysis system based on a femtosecond electron beam and a femtosecond laser light with oblique double-pulse injection was developed for studying ultrafast chemical kinetics and primary processes of radiation chemistry. The time resolution of 5.2 ps was obtained by measuring transient absorption kinetics of hydrated electrons in water. The optical density of hydrated electrons was measured as a function of the electron charge. The data indicate that the double-laser-pulse injection technique was a powerful tool for observing the transient absorptions with a good signal to noise ratio in pulse radiolysis

Tailoring the laser pulse shape to improve the quality of the self-injected electron beam in laser wakefield acceleration

International Nuclear Information System (INIS)

Upadhyay, Ajay K.; Samant, Sushil A.; Krishnagopal, S.

2013-01-01

In laser wakefield acceleration, tailoring the shape of the laser pulse is one way of influencing the laser-plasma interaction and, therefore, of improving the quality of the self-injected electron beam in the bubble regime. Using three-dimensional particle-in-cell simulations, the evolution dynamics of the laser pulse and the quality of the self-injected beam, for a Gaussian pulse, a positive skew pulse (i.e., one with sharp rise and slow fall), and a negative skew pulse (i.e., one with a slow rise and sharp fall) are studied. It is observed that with a negative skew laser pulse there is a substantial improvement in the emittance (by around a factor of two), and a modest improvement in the energy-spread, compared to Gaussian as well as positive skew pulses. However, the injected charge is less in the negative skew pulse compared to the other two. It is also found that there is an optimal propagation distance that gives the best beam quality; beyond this distance, though the energy increases, the beam quality deteriorates, but this deterioration is least for the negative skew pulse. Thus, the negative skew pulse gives an improvement in terms of beam quality (emittance and energy spread) over what one can get with a Gaussian or positive skew pulse. In part, this is because of the lesser injected charge, and the strong suppression of continuous injection for the negative skew pulse.

Development of the ion source for PDX neutral beam injection

International Nuclear Information System (INIS)

Menon, M.M.; Tsai, C.C.; Gardner, W.L.; Barber, G.C.; Haselton, H.H.; Ponte, N.S.; Ryan, P.M.; Schechter, D.E.; Stirling, W.L.; Whealton, J.H.

1979-01-01

The paper describes the development of the ion source for neutral beam injection heating of PDX plasma. After a brief description of the plasma generator, the performance characteristics of the source, with different types of grids, are described. Based on test stand results it is concluded that at least two different versions of the source should be able to meet and even exceed the neutral power and energy requirements expected out of PDX injectors

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

International Nuclear Information System (INIS)

Schroeder, Carl; Benedetti, Carlo; Bulanov, Stepan; Chen, Min; Esarey, Eric; Geddes, Cameron; Vay, J.; Yu, Lule; Leemans, Wim

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 CO 2 laser to drive the wake and a frequency-doubled Ti:Al 2 O 3 laser for ionization injection.

SQL injection detection system

OpenAIRE

Vargonas, Vytautas

2017-01-01

SQL injection detection system Programmers do not always ensure security of developed systems. That is why it is important to look for solutions outside being reliant on developers. In this work SQL injection detection system is proposed. The system analyzes HTTP request parameters and detects intrusions. It is based on unsupervised machine learning. Trained by regular request data system detects outlier user parameters. Since training is not reliant on previous knowledge of SQL injections, t...

Neutral beam program

International Nuclear Information System (INIS)

Anon.

1979-01-01

The structure of the beam injection program for the Doublet-3 device is discussed. The design considerations for the beam line and design parameters for the Doublet-3 ion souce are given. Major components of the neutral beam injector system are discussed in detail. These include the neutralizer, magnetic shielding, reflecting magnets, vacuum system, calorimeter and beam dumps, and drift duct. The planned location of the two-injector system for Doublet-3 is illustrated and site preparation is considered. The status of beamline units 1 and 2 and the future program schedule are discussed

Model calibration and beam control systems for storage rings

International Nuclear Information System (INIS)

Corbett, W.J.; Lee, M.J.; Ziemann, V.

1993-04-01

Electron beam storage rings and linear accelerators are rapidly gaining worldwide popularity as scientific devices for the production of high-brightness synchrotron radiation. Today, everybody agrees that there is a premium on calibrating the storage ring model and determining errors in the machine as soon as possible after the beam is injected. In addition, the accurate optics model enables machine operators to predictably adjust key performance parameters, and allows reliable identification of new errors that occur during operation of the machine. Since the need for model calibration and beam control systems is common to all storage rings, software packages should be made that are portable between different machines. In this paper, we report on work directed toward achieving in-situ calibration of the optics model, detection of alignment errors, and orbit control techniques, with an emphasis on developing a portable system incorporating these tools

Beam developments for the Harwell microprobe system

International Nuclear Information System (INIS)

Read, P.M.; Cookson, J.A.; Alton, G.D.

1986-01-01

A consequence of the rapid development of micron and submicron size electronic devices is the diminished applicability of high energy ion microprobes with their present resolution limitations to the study of such components. Although submicron beams have been reported the available beam current is barely sufficiently for PIXE and is not adequate for RBS. This lack of lateral resolution is due to low beam brightness at the microprobe object and aberrations in the focusing elements. As part of a program to address these problems the Harwell microprobe lens has been relocated on a new 5 MV Laddertron accelerator. The increased brightness and improved stability of this facility has so far led to a reduction in beam size from 3 x 3 μm 2 to about 2 x 2 μm 2 . The feasibility of using a liquid metal ion source has been examined with a view to achieving more substantial increases in brightness. While such sources have brightness approximately 10 5 times greater than conventional gaseous sources the highly divergent nature of the beam presents problems for the beam transport system. The use of a liquid metal source on the accelerator has been successfully demonstrated but it indicates the need for a special low aberration injection lens if brightness is to be maintained

120-keV beam direct conversion system for TFTR injectors

International Nuclear Information System (INIS)

Hamilton, G.W.

1976-01-01

Several practical motivations exist for the development of beam direct conversion systems that are compatible with the injection systems of large experiments such as the Tokamak Fusion Test Reactor (TFTR). We present a preliminary design in which we analyze the most acute problems involved in scaling up existing designs and apparatus to fulfill TFTR requirements. Some of the questions addressed are the requirements for electron suppression, gas pumping, compactness, and power densities. A new idea is presented that allows for the handling of higher beam power. The gross savings in the capital cost of injector power supplies for the TFTR will be about $7.2 million, but the net savings will be somewhat less than this. This preliminary design has not yet revealed fundamental limitations with respect to the development of beam energy-recovery systems operating at high levels of current, voltage, and power densities

Design of Injection and Extraction Systems with Optimisation of Lattice and Layout for the CERN PS2 Synchrotron

CERN Document Server

Bartmann, W

2009-01-01

The CERN Proton Synchrotron PS2 is one of the foreseen accelerators for the LHC injector upgrade. This upgrade aims first at increasing the instantaneous luminosity of LHC and second at providing a reliable beam for the CERN accelerator complex. From this aspect, the main characteristics of the PS2 are high reliability for high intensity beams. The goal of this thesis was the design of the machine’s lattice and injection/extraction systems meeting the constraints coming mainly from the LHC beam type but also from beam requirements of experiments at PS2 and the SPS. In the design, the given energy range together with filling schemes for different beam types and RF cogging were first used to define the circumference of the machine. Estimates on the space requirements of injection/extraction systems were made in order to divide the total machine length between arc and long straight section. Existing tunnels for transfer lines together with the minimisation of the total transfer line length favoured a race trac...

Plasma behavior with molecular beam injection in the HL-1m tokamak

International Nuclear Information System (INIS)

Yao Lianghua; Tang Nianyi; Cui Zhengying; Xu Deming; Deng Zhongchao; Ding Xuantong; Luo Junlin; Dong Jiafu; Guo Gancheng; Yang Shikun; Cui Chenghe; Xiao Zhenggui; Liu Dequan; Chen Xiaoping; Yan Longwen; Yan Donghai; Wang Enyao; Deng Xiwen

1999-01-01

The authors report effect of the new fueling method of high speed molecular beam injection on Tokamak confinement improvement. The present method is an improvement of conventional gas puffing, with performance comparable to the small pellet injection in HL-1M and also to the slow pellet in ASDEX. The fact that a shallower fueling can lead to similar confinement improvement as a deep one suggests that there may exist a critical position in a Tokamak plasma such that any kind of fueling will have a better confinement as long as it can give rise to density peaking at the critical position

Septa and Distributor Developments for H- Injection into the Booster from LINAC4

CERN Document Server

Borburgh, J; Fowler, T; Hourican, M; Weterings, W

2008-01-01

The construction of Linac4 requires the modification of the existing injection system of the CERN PS Booster. A new transfer line will transport 160 MeV H- ions to this machine. A system of 5 pulsed magnets (BIDIS) and 3 vertical septa (BISMV) will distribute and inject the Linac pulses into the four-vertically separated Booster rings. Subsequently the beam will be injected horizontally, using a local bump created with bumpers (BS magnets) to bring the injected H- beam together with the orbiting proton beam onto the stripper foil. To accommodate the injected H- beam, the first of the BS magnets will have to be a septum-like device, deflecting only the orbiting beam. This paper highlights the requirements and technical issues and describes the solutions to be adopted for both the BIDIS and BISMV. The results of initial prototype testing of the BIDIS magnet will also be presented.

Impurity Dynamics under Neutral Beam Injection at TJ-II (simulation)

International Nuclear Information System (INIS)

Guasp, J.; Fuentes, C.; Liniers, M.

2001-01-01

In this study the simulations of plasma transport under NBI for TJ-II, previously performed, are extended. Since than a considerable number of important modifications have been introduced in the model: change of magnetic configuration, use of experimental initial profiles, expansion of the Data base from NBI calculations and, mainly, a detailed handling of impurities with inclusion of sputtering effects. Moreover there is now a particular emphasis on the analysis of the conditions for discharge collapse and on the possible effects of single beam injection. This analysis of impurity behaviour with sputtering shows that in the expected usual cases there is no radioactive collapse and that if the recycling coefficients remain lower the unity it is always possible to find a strategy for external gas puffing leading to a stationary state, with densities below the limit and efficient NBI absorption (>50%). The radioactive collapse can appear either at high densities (central value higher than 1.4x10''20 m''3), excessive influx of impurities (i. e. with sputtering rates higher than twice the expected values) o for insufficient injected beam power (less than 45 kW). The present study analyses only the 100 4 4 6 4 configuration of TJ-II, but future works will start a systematic scan of configuration using this same model. (Author) 12 Refs

Transverse Feedback for Electron-Cooled DC-Beam at COSY

International Nuclear Information System (INIS)

Kamerdzhiev, V.; Dietrich, J.

2004-01-01

At the cooler synchrotron COSY, high beam quality is achieved by means of beam cooling. In the case of intense electron-cooled beams, fast particle losses due to transverse coherent beam oscillations are regularly observed. To damp the instabilities a transverse feedback system was installed and successfully commissioned. Commissioning of the feedback system resulted in a significant increase of the e-cooled beam intensity by single injection and when cooling and stacking of repeated injections is applied. External experiments profit from the small diameter beams and the reduced halo. A transverse damping system utilizing a pick-up, signal processing electronics, power amplifiers, and a stripline deflector is introduced. Beam current and Schottky spectra measurements with the vertical feedback system turned on and off are presented

Tokamak Fusion Test Reactor neutral beam injection system vacuum chamber

International Nuclear Information System (INIS)

Pedrotti, L.R.

1977-01-01

Most of the components of the Neutral Beam Lines of the Tokamak Fusion Test Reactor (TFTR) will be enclosed in a 50 cubic meter box-shaped vacuum chamber. The chamber will have a number of unorthodox features to accomodate both neutral beam and TFTR requirements. The design constraints, and the resulting chamber design, are presented

A Computer Program to Measure the Energy Spread of Multi-turn Beam in the Fermilab Booster at Injection

Science.gov (United States)

Nelson, Jovan; Bhat, Chandrashekhara; Hendricks, Brian

2016-03-01

We have developed a computer program interfaced with the ACNET environment for Fermilab accelerators in order to measure the energy spread of the injected proton beam from the LINAC, at the energy of 400 MeV. This program allows the user to configure a digitizing oscilloscope and timing devices to optimize data acquisition from a resistive wall current monitor. When the program is launched, it secures control of the oscilloscope and then generates a ``one-shot'' timeline which initiates injection into the Booster. Once this is complete, a kicker is set to create a notch in the beam and the line charge distribution data is collected by the oscilloscope. The program then analyzes this data in order to obtain notch width, beam revolution period, and beam energy spread. This allows the program to be a possible useful diagnostic tool for the beginning of the acceleration cycle for the proton beam. Thank you to the SIST program at Fermilab.

Injection and accumulation method in the TARN

International Nuclear Information System (INIS)

Yamada, S.; Katayama, T.

1979-03-01

The test accumulation ring for NUMATRON (TARN) is being constructed at INS, University of Tokyo. The main purpose of the TARN is to establish some techniques related to beam injection and RF stacking, ultrahigh vacuum, and beam monitoring and handling. In this paper, the injection and accumulation methods in the TARN are described. The combination of multiturn injection and RF stacking is applied to the TARN. Heavy ions from the INS sector focusing (SF) cyclotron are injection through a magnetic and an electrostatic inflectors. Two pulse magnets and a bump field excited by square wave current are used for the multiturn injection method. The procedure of the RF stacking is as follows. The beam from the cyclotron is transported to the ring, and is injected by a multiturn method. Then, the RF accelerating voltage is put on, and the beam is captured in the stable region of the RF acceleration. The RF voltage and the frequency are adiabatically changed, and the beam is moved to the stacking orbit. The RF voltage is put off, and the beam remains on the stacking orbit. In the present system, a repetitive stacking scheme is applied for the RF stacking. The momentum spread after the RF stacking is approximately proportional to the stacking number in synchrotron phase space. The stacking number is chosen so that the total aperture required for the combined method may not exceed the available aperture in the ring doughnut. (Kato, T.)

Plasma heating by injection of neutral beams into TFR 600

International Nuclear Information System (INIS)

1981-01-01

Experimental results from quasi-perpendicular high power (up to 1.2 MW) neutral beam injection in the TFR 600 tokamak are reported. The trapped fast ions show all the characteristics of a classical feature. This allows us to study the behaviour of a dense plasma (n approximately equal to 10 14 cm -3 ) whose electron and ion temperatures are significantly changed by fast neutrals injection (ΔTsub(e,i)>300 eV). No increase of the global energy confinement time has been observed, but at low q value a large increase of internal disruptions appears. This fact permits to partly enlighten the internal disruptions mechanism and to emphasize their importance. 1-D simulation calculations are also reported; changes in the electron and ion heat conduction, necessary to explain most of the experimental results observed during the internal disruptions will be discussed

The Injection System of SAGA Light Source

CERN Document Server

Iwasaki, Yoshitaka; Ohgaki, Hideaki; Okajima, Toshihiro; Takabayashi, Yuichi; Tomimasu, Takio; Yoshida, Katuhide

2005-01-01

Saga light Source is a 1.4-GeV electron storage ring with a circumference of 75.6m. The injector is a 250-MeV linac producing 1 ms macro-pulse with a peak current of 12mA and repetition rate of 1Hz. The output beam from the linac is transported though a transport line, and injected into the ring though a septum magnet with a bending angle of 20-degree. The transport line consists of two bending magnets, two quadrupole doublelets, and a quadrupole singlet. The bump orbit is formed by four kicker magnets, two of which are installed at both sides of septum magnet, and other two are positioned apart by one magnet cell of the ring. They are excited by sinusoidal electric currents with a half width of 0.5 ms. The beam optics for the injection trajectory is computed and shown at control room, the parameters for which are provided directly from the power supply control server PC. The operator is able to see real-time result of the beam trajectory calculation. This tool is quite effective to optimize the magnets param...

Imaging instrument for positron emitting heavy ion beam injection

International Nuclear Information System (INIS)

Llacer, J.; Chatterjee, A.; Jackson, H.C.; Lin, J.C.; Zunzunegui, M.V.

1978-10-01

The design and performance of an instrument for the imaging of coincidence annihilation gamma rays emitted from the end point of the trajectories of radioactive high-energy heavy ions is described. The positron-emitting heavy ions are the result of nuclear fragmentation of accelerated heavy ions used in cancer therapy or diagnostic medicine. The instrument constructed is capable of locating the ion beam trajectory end point within 1 mm for an injected activity of 200 nanoCi in a measurement time of 1 sec in some favorable conditions. Limited imaging in three dimensions is also demonstrated

Versatile H+ beam chopper system at LAMPF

International Nuclear Information System (INIS)

Lunsford, J.S.; Lawrence, G.P.; Bentley, R.F.

1979-01-01

The H + chopper system at LAMPF provides two modes (A and B) of beam chopping. Mode A provides single micropulses separated by 1 μs or more. Mode B provides a single pulse 50-ns to 10-μs long at the LAMPF repetition rate of 12 Hz. The mode of operation is selected with coaxial relays which can switch during the dead time between LAMPF macropulses. The chopper consists of 1-m-long push-pull helical-wound slow-wave deflecting structures having an axial pulse velocity of 0.04c, which matches the velocity of the proton beam. The helix ground-planes are biased by a pulser providing push-pull 500-V pulses to deflect the H + beam from the injection channel. In chopping mode A, the helical windings are driven by push-pull, 1000-V, 5-ns pulses delivered by a circuit utilizing avalanche transistors and planar triodes. In mode B, the helical windings are driven by push-pull, 1000-V, 50-ns to 10-μs long pulses, produced by a circuit utilizing beam-power tetrodes and fast SCRs. In both modes, these pulses cancel the ground-plane bias and permit beam pulses to be delivered to the linac

Monte-Carlo calculation of perpendicular neutral-beam injection in helical systems

International Nuclear Information System (INIS)

Hanatani, K.; Wakatani, M.; Uo, K.

1981-01-01

The effect of a helical field ripple on the slowing-down process of the fast ions created by neutral injection is investigated numerically. For this purpose, the guiding-centre orbits are followed in a model magnetic field without plasma current, on the assumption that the slowing-down process is to be classical. Optimum injection angles in two types of helical magnetic traps are compared. One is the Heliotron-E configuration with a large rotational transform and deep helical ripple; the other one is the conventional stellarator field with a small rotational transform and shallow helical ripple. In contrast to the stellarator, the heating efficiency as calculated for Heliotron-E does not decrease monotonically when the injection angle is perpendicular to the toroidal direction; a heating efficiency of above 70% was obtained for perpendicular injection into a high-density plasma with negligible charge-exchange loss. The difference in heating efficiency versus injection angle between heliotron and conventional stellarator fields is explained by a difference in drift motion of the helically trapped fast ions. (author)

Electromagnetic radiation from beam-plasma instabilities

International Nuclear Information System (INIS)

Stenzel, R.L.; Whelan, D.A.

1982-01-01

This chapter investigates the mechanism by which unstable electrostatic waves of an electron-beam plasma system are converted into observed electromagnetic waves. Electromagnetic radiation arises from both natural beam-plasma systems (e.g., type III solar bursts and kilometric radiation), and from man-made electron beams injected from rockets and spacecraft. A pulsed magnetized discharge plasma is produced with a 1 m diam. oxide-coated cathode and the discussed experiment is performed in the quiescent afterglow. The primary beam-plasma instability involves the excitation of electrostatic plasma waves. Electromagnetic radiation from the beam-plasma system is observed with microwave antennas outside the plasma (all probes removed) or with coax-fed dipoles which can be inserted radially and axially into the plasma. The physical process of mode coupling by which electromagnetic radiation is generated in an electrostatic beam-plasma instability is identified. The results are relevant to beam injection experiments from rockets or satellites into space plasmas. The limited penetration of the beam current into the plasma due to instabilities is demonstrated

Evolution of High Intensity Beams in the CERN PS Booster after H⁻ Injection and Phase Space Painting

CERN Document Server

Cieslak-Kowalska, Magdalena; Benedetto, Elena; Bracco, Chiara

2016-01-01

With the LHC Injector Upgrade (LIU) project, the injection energy of PS Booster (PSB) ' first circular accelerator in the LHC injector chain ' will be raised from 50 MeV to 160 MeV and the present multiturn injection will be upgraded to H⁻ injection with transverse and longitudinal painting. In the scope of this project, it is planned to double the beam intensities, profiting from the fact that the βγ2 factor will be two times larger (0.35 at 50 MeV and 0.71 at 160 MeV), so the resulting tune spread driven by a direct space charge should remain similar. This paper describes the feasibility to double the intensity of high intensity and large emittance beams, looking into the evolution under space charge and taking into account losses constrains in the ring and in the extraction lines.

Dust appearance rates during neutral beam injection and after oxygen bake in the DIII-D tokamak

International Nuclear Information System (INIS)

Yu, J.H.; Smirnov, R.D.; Rudakov, D.L.

2011-01-01

A simple model to quantify source and sink terms of dust observed in tokamaks using fast visible imaging is presented. During neutral beam injection (NBI), dust appearance rates increase in front of the neutral beam port by up to a factor of 5. The images show dust streaming from the port box as previously settled dust becomes mobilized during beam injection. Following an oxygen bake and vent, the dust observation rate is a factor of 2 lower than that after a vessel entry vent with no oxygen bake. Detected dust levels decay on a shot-to-shot basis in a roughly exponential fashion, with a decay time of approximately 20 s of plasma exposure. Appearance rates of dust mass are estimated using assumed lognormal and power law functional forms for the dust size distribution. The two dust size distributions differ significantly on the amount the dust material carried by the largest particles, highlighting the need for further dust studies in order to make accurate forecasts to ITER.

Thermal analysis of EAST neutral beam injectors for long-pulse beam operation

Science.gov (United States)

Chundong, HU; Yongjian, XU; Yuanlai, XIE; Yahong, XIE; Lizhen, LIANG; Caichao, JIANG; Sheng, LIU; Jianglong, WEI; Peng, SHENG; Zhimin, LIU; Ling, TAO; the NBI Team

2018-04-01

Two sets of neutral beam injectors (NBI-1 and NBI-2) have been mounted on the EAST tokamak since 2014. NBI-1 and NBI-2 are co-direction and counter-direction, respectively. As with in-depth physics and engineering study of EAST, the ability of long pulse beam injection should be required in the NBI system. For NBIs, the most important and difficult thing that should be overcome is heat removal capacity of heat loaded components for long-pulse beam extraction. In this article, the thermal state of the components of EAST NBI is investigated using water flow calorimetry and thermocouple temperatures. Results show that (1) operation parameters have an obvious influence on the heat deposited on the inner components of the beamline, (2) a suitable operation parameter can decrease the heat loading effectively and obtain longer beam pulse length, and (3) under the cooling water pressure of 0.25 MPa, the predicted maximum beam pulse length will be up to 260 s with 50 keV beam energy by a duty factor of 0.5. The results present that, in this regard, the EAST NBI-1 system has the ability of long-pulse beam injection.

A proposal of a beam injection device for the proton storage ring of JAERI neutron science project

International Nuclear Information System (INIS)

Suzuki, Yasuo

1998-01-01

A new injection device (a charge-exchange device) with light and magnetic field, is proposed for a proton storage ring of JAERI Neutron Science Project. This injection device is composed of a neutralizer and an ionizer. The neutralizer strips electrons of H 0 beam into H - one with the undulator magnetic field. The ionizer which is composed of undulator magnets and an optical resonator placed along a straight part in the storage ring, can ionize effectively the H 0 beam excited to n=3 level by a laser beam into H + one. Adopting the 2nd harmonics of Nd : YAG laser, the powerful laser on the market can be used, and the required items of the technological development can be minimized. The energy of the particle beam, however, should be accelerated up to 1.587 GeV by 6% increase from 1.5 GeV. In this device, the non-charge-exchange rate and beam-spill can be minimized by decreasing the deflection angle of the beam which occurs at the charge-exchange process. This method can be realized with exiting technologies and there are not any effects on the trajectory of the ring-circulating proton beam due to scatterings by the foil as the usual charge-exchange devices. This device, therefore, will be an optimal and highly effective method of the least beam-spill as the injector of the high power proton storage ring. (author)

Echo 2: a study of electron beams injected into the high-latitude ionosphere from a large sounding rocket

International Nuclear Information System (INIS)

Winckler, J.R.; Arnoldy, R.L.; Hendrickson, R.A.

1975-01-01

The Black Brant V-C Echo 2 rocket was launched at Fort Churchill on September 25, 1972, and it injected 64-ms pulses of electron beams of 80-mA current and 45-keV voltage into the ionosphere. This paper studies the responses of on-board electrostatic deflection and solid state detectors to injected electrons after motion in the near ionosphere and atmosphere. It is shown that it was only through some form of scattering that the detectors could sense the injected beam electrons. By means of 'phase maps' of injection and detection pitch angles a number of distinct regions are found corresponding to a rocket scattering halo, an atmospheric scattering halo, a region of weak responses, and a source of strong scattering above the rocket. The atmospheric scattering has been compared with the theoretical and experimental results of the Echo 1 experiment, and it is found to be in reasonable agreement. The rocket halo is discussed qualitatively; but no explanation is found for the backscatter from above the rocket, which may be associated with an occasional violent beam instability. This analysis has been carried out to better understand the complexities of electron motion observed near large rockets carrying artifical electron accelerators as a guide in the planning of future experiments

Application of the OPTIMUS Code to the Neutral Beam Injection System of TJ-II

International Nuclear Information System (INIS)

Fuentes, C.; Liniers, M.; Guasp, J.

1998-01-01

The different losses processes affecting a neutral beam since is born into the ions source until is coming into the fusion machine, are dependent of the residual gas pressure distribution inside injector. The OPTIMUS code analyzes that losses and calculates the pressure distribution inside one injector with specific geometry. The adaptation of injector to TJ-II has not required important design changes, only the operating range of the gas flow and the pumping speed have modified. The calculations show that the required gas flows for the optimal operation of the system ned an independent pumping system for the calorimeter box with a pumping speed of 1200001/s. The system efficiency is not affected by an hypothetical beaming effect and it is found also that with a proper conditioning of the injector walls, so that the absorption coefficients do not surpass excessively the unity value, the injector operation remains optimal. (Author) 8 refs

Current drive by neutral beams, rotating magnetic fields and helicity injection in compact toroids

International Nuclear Information System (INIS)

Farengo, R.; Arista, N.R.; Lifschitz, A.F.; Clemente, R.A.

2003-01-01

The use of neutral beams (NB) for current drive and heating in spheromaks, the relaxed states of flux core spheromaks (FCS) sustained by helicity injection and the effect of ion dynamics on rotating magnetic field (RMF) current drive in spherical tokamaks (ST) are studied. (author)

Protection against Accidental Beam Losses at the LHC

CERN Document Server

Wenninger, Jörg

2005-01-01

Protection of the LHC against uncontrolled beam losses is of prime importance due to the very high stored beam energy. For nominal beam intensities, each of the two 7 TeV/c proton beams has a stored energy of 360 MJ threatening to damage accelerator equipment. At injection a number of passive beam absorbers must be correctly positioned and specific procedures have been proposed to ensure safe injection of high intensity. The LHC beam dump block being the only LHC element that can safety absorb the full LHC beam, it is essential that the beams are extracted unto the dump block in case of emergency. The failure time constants extend from 100 microseconds to few seconds depending on the equipment. Failures must be detected at a sufficiently early stage and transmitted to the beam interlock system that triggers the beam dumping system. To ensure safe operation the machine protection system uses a variety of systems to detect such failures. The strategy for protection of the LHC will be illustrated, with emphasis ...

Physics of the current injection process during localized helicity injection

Science.gov (United States)

Hinson, Edward Thomas

An impedance model has been developed for the arc-plasma cathode electron current source used in localized helicity injection tokamak startup. According to this model, a potential double layer (DL) is established between the high-density arc plasma (narc ˜ 1021 m-3) in the electron source, and the less-dense external tokamak edge plasma (nedge ˜ 10 18 m-3) into which current is injected. The DL launches an electron beam at the applied voltage with cross-sectional area close to that of the source aperture: Ainj ≈ 2 cm 2. The injected current, Iinj, increases with applied voltage, Vinj, according to the standard DL scaling, Iinj ˜ V(3/2/ inj), until the more restrictive of two limits to beam density nb arises, producing Iinj ˜ V(1/2/inj), a scaling with beam drift velocity. For low external tokamak edge density nedge, space-charge neutralization of the intense electron beam restricts the injected beam density to nb ˜ nedge. At high Jinj and sufficient edge density, the injected current is limited by expansion of the DL sheath, which leads to nb ˜ narc. Measurements of narc, Iinj , nedge, Vinj, support these predicted scalings, and suggest narc as a viable control actuator for the source impedance. Magnetic probe signals ≈ 300 degrees toroidally from the injection location are consistent with expectations for a gyrating, coherent electron beam with a compact areal cross-section. Technological development of the source has allowed an extension of the favorable Iinj ˜ V(1/2/inj) to higher power without electrical breakdown.

High Voltage Performance of the Beam Screen of the LHC Injection Kicker Magnets

CERN Document Server

Barnes, MJ; Bregliozzi, G; Calatroni, S; Costa Pinto, P; Day, H; Ducimetière, L; Kramer, T; Namora, V; Mertens, V; Taborelli, M

2014-01-01

The LHC injection kicker magnets include beam screens to shield the ferrite yokes against wakefields resulting from the high intensity beam. The screening is provided by conductors lodged in the inner wall of a ceramic support tube. The design of the beam screen has been upgraded to overcome limitations and permit LHC operation with increasingly higher bunch intensity and short bunch lengths: the new design also significantly reduces the electric field associated with the screen conductors, decreasing the probability of electrical breakdown. The high voltage conditioning process for the upgraded kicker magnets is presented and discussed. In addition a test setup has been utilized to study flashover, on the inner wall of the ceramic tube, as a function of both applied voltage and vacuum pressure: results from the test setup are presented.

Reduction of Surface Flashover of the Beam Screen of the LHC Injection Kickers

CERN Document Server

Barnes, M J; Calatroni, S; Caspers, F; Ducimetière, L; Gomes Namora, V; Mertens, V; Noulibos, R; Taborelli, M; Teissandier, B; Uythoven, J; Weterings, W

2013-01-01

The LHC injection kicker magnets include beam screens to shield the ferrite yokes against wake fields resulting from the high intensity beam. The screening is provided by conductors lodged in the inner wall of a ceramic support tube. LHC operation with increasingly higher bunch intensity and short bunch lengths, requires improved ferrite screening. This will be implemented by additional conductors; however these must not compromise the good high-voltage behaviour of the kicker magnets. Extensive studies have been carried out to better satisfy the often conflicting requirements for low beam coupling impedance, fast magnetic field rise-time, ultra-high vacuum and good high voltage behaviour. A new design is proposed which significantly reduces the electric field associated with the screen conductors. Results of high voltage tests are also presented.

DIII-D tokamak control and neutral beam computer system upgrades

International Nuclear Information System (INIS)

Penaflor, B.G.; McHarg, B.B.; Piglowski, D.A.; Pham, D.; Phillips, J.C.

2004-01-01

This paper covers recent computer system upgrades made to the DIII-D tokamak control and neutral beam computer systems. The systems responsible for monitoring and controlling the DIII-D tokamak and injecting neutral beam power have recently come online with new computing hardware and software. The new hardware and software have provided a number of significant improvements over the previous Modcomp AEG VME and accessware based systems. These improvements include the incorporation of faster, less expensive, and more readily available computing hardware which have provided performance increases of up to a factor 20 over the prior systems. A more modern graphical user interface with advanced plotting capabilities has improved feedback to users on the operating status of the tokamak and neutral beam systems. The elimination of aging and non supportable hardware and software has increased overall maintainability. The distinguishing characteristics of the new system include: (1) a PC based computer platform running the Redhat version of the Linux operating system; (2) a custom PCI CAMAC software driver developed by general atomics for the kinetic systems 2115 serial highway card; and (3) a custom developed supervisory control and data acquisition (SCADA) software package based on Kylix, an inexpensive interactive development environment (IDE) tool from borland corporation. This paper provides specific details of the upgraded computer systems

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

Energy Technology Data Exchange (ETDEWEB)

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

2016-05-15

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

Performance of magnetically-injected-plasma opening switches on the particle beam fusion accelerator 2

International Nuclear Information System (INIS)

Rochau, G.E.; McDaniel, D.H.; Mendel, C.W.; Sweeney, M.A.; Moore, W.B.S.; Mowrer, G.R.; Zagar, D.M.

1990-01-01

Plasma opening switch (POS) experiments have been performed on the PBFA II ion beam accelerator to develop a switch which will provide voltage and power gain to an applied-B lithium ion diode. These experiments have successfully coupled power to electron and ion beam diodes using a Magnetically-Injected-Plasma (MIP) POS. Carbon plasma with electron densities of 1 x 10 12 to 2 x 10 13 /cm 3 have been injected from the anode into the 8 cm gap of the 20-ohm Magnetically-Insulated-Transmission Line (MITL) of PBFA II along a B r,z magnetic field. The MIP switch uses the inertia of the plasma to keep the switch closed and the magnetic pressure of B θ from the conduction current to open the switch. The configuration of the injecting magnetic field and the plasma source has a significant effect on the efficiency of coupling power to high impedance loads. Plasma near the center of the injecting magnetic field limits the opening impedance of the switch and subsequently the power delivered to the load. The axial location of the switch with respect to the load has also been identified as a critical parameter in increasing the coupling efficiency. A length of 10 to 20 cm of MITL between the POS and the load has increased the power delivered to the load. Data on switch performance with high impedance loads and factors which improved performance are discussed

Injection Bucket Jitter Compensation Using Phase Lock System at Fermilab Booster

Energy Technology Data Exchange (ETDEWEB)

Seiya, K. [Fermilab; Drennan, C. [Fermilab; Pellico, W. [Fermilab; Chaurize, S. [Fermilab

2017-05-12

The extraction bucket position in the Fermilab Booster is controlled with a cogging process that involves the comparison of the Booster rf count and the Recycler Ring revolution marker. A one rf bucket jitter in the ex-traction bucket position results from the variability of the process that phase matches the Booster to the Recycler. However, the new slow phase lock process used to lock the frequency and phase of the Booster rf to the Recycler rf has been made digital and programmable and has been modified to correct the extraction notch position. The beam loss at the Recycler injection has been reduced by 20%. Beam studies and the phase lock system will be discussed in this paper.

Power deposition by neutral beam injected fast ions in field-reversed configurations

International Nuclear Information System (INIS)

Takahashi, Toshiki; Kato, Takayuki; Kondoh, Yoshiomi; Iwasaka, Naotaka

2004-04-01

Effects of Coulomb collisions on neutral beam (NB) injected fast ions into Field-Reversed Configuration (FRC) plasmas are investigated by calculating the single particle orbits, where the ions are subject to the slowing down and pitch angle collisions. The Monte-Carlo method is used for the pitch angle scattering, and the friction term is added to the equation of motion to show effects of slowing down collision such as the deposited power profile. Calculation parameters used are relevant to the NB injection on the FRC Injection Experiment (FIX) device. It is found that the dominant local power deposition occurs in the open field region between the X-point and the mirror point because of a concentration of fast ions and a longer duration travel at the mirror reflection point. In the present calculation, the maximum deposited power to the FRC plasma is about 10% of the injected power. Although the pitch angle scattering by Coulomb collision destroys the mirror confinement of NB injected fast ions, this effect is found negligible. The loss mechanism due to non-adiabatic fast ion motion, which is intrinsic in non-uniform FRC plasmas, affects much greater than the pitch angle scattering by Coulomb collision. (author)

Recent improvements to the DIII-D neutral beam instrumentation and control system

International Nuclear Information System (INIS)

Kellman, D.H.; Hong, R.

1997-11-01

The DIII-D neutral beam (NB) instrumentation and control (I and C) system provides for operational control and synchronization of the eight DIII-D neutral beam injection systems, as well as for pertinent data acquisition and safety interlocking. Recently, improvements were made to the I and C system. With the replacement of the NB control computers, new signal interfacing was required to accommodate the elimination of physical operator panels, in favor of graphical user interface control pages on computer terminal screens. The program in the mode control (MC) programmable logic controller (PLC), which serves as a logic-processing interface between the NB control computers and system hardware, was modified to improve the availability of NB heating of DIII-D plasmas in the event that one or more individual beam systems suddenly become unavailable while preparing for a tokamak experimental shot sequences. An upgraded computer platform was adopted for the NB control system operator interface and new graphical user interface pages were developed to more efficiently display system status data. A failure mode of the armor tile infrared thermometers (pyrometers), which serve to terminate beam pulsing if beam shine-through overheats wall thermal shielding inside the DIII-D tokamak, was characterized such that impending failures can be detected and repairs effected to mitigate beam system down-time. The hardware that controls gas flow to the beamline neutralizer cells was upgraded to reduce susceptibility to electromagnetic interference (EMI), and interlocking was provided to terminate beam pulsing in the event of insufficient neutralizer gas flow. Motivation, implementation, and results of these improvements are presented

Calculation of injection and extraction orbits for the IPCR SSC

International Nuclear Information System (INIS)

Goto, A.; Yano, Y.; Kishida, N.; Nakanishi, N.; Wada, T.

1982-01-01

Calculations of beam trajectories in the injection and extraction systems for the IPCR SSC were done and the characteristics of those elements were determined. Beam centering for single turn extraction by use of first harmonic fields were also studied. The rather simple conditions at the injection point for a well-centered acceleration orbit are also discussed

Evolution of radiation losses and importance of charge exchange between plasma impurities and injection beam neutrals in the W VII-A stellarator

International Nuclear Information System (INIS)

Smeulders, P.

1981-01-01

In certain discharges during Neutral Injection (N.I.) (84 0 CO-injection) in the 1 = 2, m = 5 WENDELSTEIN VII-A Stellarator impurity accumulation in the plasma center seems to occur as seen by bolometric, spectroscopic and ultra soft X-ray (USX) measurement. The time evolution of the radiation losses is shown. Three possible sources of the impurities which are responsible for the high central radiation losses are: - Beam injected impurities. - Plasma wall interaction. - Molybdenum protection plates. Possible mechanisms that can be responsible for the central impurity accumulations are: - An inward flow of the plasma or beam impurities. - An increased peaking of the depostion of the beam impurities. Various factors influencing the behaviour of the central radiation are mentioned. (orig./AH)

On finding the analytic dependencies of the external field potential on the control function when optimizing the beam dynamics

Science.gov (United States)

Ovsyannikov, A. D.; Kozynchenko, S. A.; Kozynchenko, V. A.

2017-12-01

When developing a particle accelerator for generating the high-precision beams, the injection system design is of importance, because it largely determines the output characteristics of the beam. At the present paper we consider the injection systems consisting of electrodes with given potentials. The design of such systems requires carrying out simulation of beam dynamics in the electrostatic fields. For external field simulation we use the new approach, proposed by A.D. Ovsyannikov, which is based on analytical approximations, or finite difference method, taking into account the real geometry of the injection system. The software designed for solving the problems of beam dynamics simulation and optimization in the injection system for non-relativistic beams has been developed. Both beam dynamics and electric field simulations in the injection system which use analytical approach and finite difference method have been made and the results presented in this paper.

The effect of off-axis neutral beam injection on sawtooth stability in ASDEX Upgrade and Mega-Ampere Spherical Tokamak

International Nuclear Information System (INIS)

Chapman, I. T.; de Bock, M. F.; Pinches, S. D.; Turnyanskiy, M. R.; Igochine, V. G.; Maraschek, M.; Tardini, G.

2009-01-01

Sawtooth behavior has been investigated in plasmas heated with off-axis neutral beam injection in ASDEX Upgrade [A. Herrmann and O. Gruber, Fusion Sci. Technol. 44, 569 (2003)] and the Mega-Ampere Spherical Tokamak (MAST) [A. Sykes et al., Nucl. Fusion 41, 1423 (2001)]. Provided that the fast ions are well confined, the sawtooth period is found to decrease as the neutral beam is injected further off-axis. Drift kinetic modeling of such discharges qualitatively shows that the passing fast ions born outside the q=1 rational surface can destabilize the n=1 internal kink mode, thought to be related to the sawtooth instability. This effect can be enhanced by optimizing the deposition of the off-axis beam energetic particle population with respect to the mode location.

Optics Measurements and Matching of TT2-TT10 Line for Injection of the LHC Beam in the SPS

CERN Document Server

Benedetto, E

2008-01-01

A well matched injection in the SPS is very important for preserving the emittance of the LHC beam. The paper presents the algorithms used for the analysis and the results of the 2007 optics measurements campaign done in the transfer line TT2-TT10 and in the SPS. The dispersion is computed by varying the beam momentum and recording the offsets at the BPMs, while the Twiss parameters and emittance measurements in TT2-TT10 are performed with beam profile monitors equipped with OTR screens. Finally, on the basis of such measurements, a betatron and dispersion matching of TT2-TT10 for injection in the SPS has been performed and successfully put in operation since October 2007.

The development of an expert system to tune a beam line

International Nuclear Information System (INIS)

Schultz, D.E.; Brown, P.A.; British Columbia Univ., Vancouver, BC

1989-01-01

The experience of developing an Expert System to aid in the tuning of the Ion Source Injection beam line at TRIUMF is described. The challenging and complex task of introducing Expert System technology into an established accelerator operation is outlined. Success in this environment depends strongly on the choice of project, the choice of experts, the choice of tools, and the methods used to represent the expertise. All these choices are discussed

Characteristics of a long-pulse (30-s), high-power (4-MW) ion source for neutral beam injection

International Nuclear Information System (INIS)

Menon, M.M.; Barber, G.C.; Combs, S.K.

1983-01-01

A quasi-steady-state ion source has been developed for neutral beam injection applications. It is of the duoPIGatron type designed for delivering 50 A of hydrogen ions at 80 keV for 30-s-long pulses. Ion beams of 40 A at 75 keV were extracted for pulse lengths up to 30 s, maintaining excellent optical quality in the beam for the entire pulse duration. The design features and operational characteristics of the ion source are elaborated

Simulation of the injection damping and resonance correction systems for the HEB of the SSC

Energy Technology Data Exchange (ETDEWEB)

Li, M.; Zhang, P.; Machida, S.

1993-02-01

An injection damping and resonance correction system for the High Energy Booster (HEB) of the Superconducting Super Collider (SSC) was investigated by means of multiparticle tracking. For an injection damping study, the code Simpsons is modified to utilize two Beam Position Monitors (BPM) and two dampers. ne particles of 200 Gev/c, numbered 1024 or more, with Gaussian distribution in 6-D phase space are injected into the HEB with certain injection offsets. The whole bunch of particles is then kicked in proportion to the BPM signals with some upper limit. Tracking these particles up to several hundred turn while the damping system is acting shows the turn-by-turn emittance growth, which is caused by the tune spread due to nonlinearity of the lattice and residual chromaticity with synchrotron oscillations. For a resonance correction study, the operating tune is scanned as a function of time so that a bunch goes through a resonance. The performance of the resonance correction system is demonstrated. We optimize the system parameters which satisfy the emittance budget of the HEB, taking into account the realistic hardware requirement.

Simulation of the injection damping and resonance correction systems for the HEB of the SSC

Energy Technology Data Exchange (ETDEWEB)

Li, M.; Zhang, P.; Machida, S. (Superconducting Super Collider Laboratory, Dallas, Texas 75237 (United States))

1993-12-25

An injection damping and resonance correction system for the High Energy Booster (HEB) of the Superconducting Super Collider (SSC) was investigated by means of multiparticle tracking. For an injection damping study, the code Simpsons is modified to utilize two Beam Position Monitors (BPM) and two dampers. The particles of 200 Gev/c, numbered 1024 or more, with Gaussian distribution in 6-D phase space are injected into the HEB with certain injection offsets. The whole bunch of particles is then kicked in proportion to the BPM signals with some upper limit. Tracking these particles up to several hundred turns while the damping system is acting shows the turn-by-turn emittance growth, which is caused by the tune spread due to nonlinearity of the lattice and residual chromaticity with synchrotron oscillations. For a resonance correction study, the operating tune is scanned as a function of time so that a bunch goes through a resonance. The performance of the resonance correction system is demonstrated. We optimize the system parameters which satisfy the emittance budget of the HEB, taking into account the realistic hardware requirement.

Inertial fusion energy target injection, tracking, and beam pointing

International Nuclear Information System (INIS)

Petzoldt, R.W.

1995-01-01

Several cryogenic targets must be injected each second into a reaction chamber. Required target speed is about 100 m/s. Required accuracy of the driver beams on target is a few hundred micrometers. Fuel strength is calculated to allow acceleration in excess of 10,000 m/s 2 if the fuel temperature is less than 17 K. A 0.1 μm thick dual membrane will allow nearly 2,000 m/s 2 acceleration. Acceleration is gradually increased and decreased over a few membrane oscillation periods (a few ms), to avoid added stress from vibrations which could otherwise cause a factor of two decrease in allowed acceleration. Movable shielding allows multiple targets to be in flight toward the reaction chamber at once while minimizing neutron heating of subsequent targets. The use of multiple injectors is recommended for redundancy which increases availability and allows a higher pulse rate. Gas gun, rail gun, induction accelerator, and electrostatic accelerator target injection devices are studied, and compared. A gas gun is the preferred device for indirect-drive targets due to its simplicity and proven reliability. With the gas gun, the amount of gas required for each target (about 10 to 100 mg) is acceptable. A revolver loading mechanism is recommended with a cam operated poppet valve to control the gas flow. Cutting vents near the muzzle of the gas gun barrel is recommended to improve accuracy and aid gas pumping. If a railgun is used, we recommend an externally applied magnetic field to reduce required current by an order of magnitude. Optical target tracking is recommended. Up/down counters are suggested to predict target arrival time. Target steering is shown to be feasible and would avoid the need to actively point the beams. Calculations show that induced tumble from electrostatically steering the target is not excessive

High beam current shut-off systems in the APS linac and low energy transfer line

International Nuclear Information System (INIS)

Wang, X.; Knott, M.; Lumpkin, A.

1994-01-01

Two independent high beam current shut-off current monitoring systems (BESOCM) have been installed in the APS linac and the low energy transport line to provide personnel safety protection in the event of acceleration of excessive beam currents. Beam current is monitored by a fast current transformer (FCT) and fully redundant supervisory circuits connected to the Access Control Interlock System (ACIS) for beam intensity related shutdowns of the linac. One FCT is located at the end of the positron linac and the other in the low energy transport line, which directs beam to the positron accumulator ring (PAR). To ensure a high degree of reliability, both systems employ a continuous self-checking function, which injects a test pulse to a single-turn test winding after each ''real'' beam pulse to verify that the system is fully functional. The system is designed to be fail-safe for all possible system faults, such as loss of power, open or shorted signal or test cables, loss of external trigger, malfunction of gated integrator, etc. The system has been successfully commissioned and is now a reliable part of the total ACIS

Formation and sustainment of field reversed configuration (FRC) plasmas by spheromak merging and neutral beam injection

Energy Technology Data Exchange (ETDEWEB)

Yamada, Masaaki [Princeton Plasma Physics Laboratory, Princeton University Princeton, New Jersey USA (United States)

2016-03-25

This paper briefly reviews a compact toroid reactor concept that addresses critical issues for forming, stabilizing and sustaining a field reversed configuration (FRC) with the use of plasma merging, plasma shaping, conducting shells, neutral beam injection (NBI). In this concept, an FRC plasma is generated by the merging of counter-helicity spheromaks produced by inductive discharges and sustained by the use of neutral beam injection (NBI). Plasma shaping, conducting shells, and the NBI would provide stabilization to global MHD modes. Although a specific FRC reactor design is outside the scope of the present paper, an example of a promising FRC reactor program is summarized based on the previously developed SPIRIT (Self-organized Plasmas by Induction, Reconnection and Injection Techniques) concept in order to connect this concept to the recently achieved the High Performance FRC plasmas obtained by Tri Alpha Energy [Binderbauer et al, Phys. Plasmas 22,056110, (2015)]. This paper includes a brief summary of the previous concept paper by M. Yamada et al, Plasma Fusion Res. 2, 004 (2007) and the recent experimental results from MRX.

Laboratory Measurements of Electrostatic Solitary Structures Generated by Beam Injection

International Nuclear Information System (INIS)

Lefebvre, Bertrand; Chen, Li-Jen; Gekelman, Walter; Pribyl, Patrick; Vincena, Stephen; Kintner, Paul; Pickett, Jolene; Chiang, Franklin; Judy, Jack

2010-01-01

Electrostatic solitary structures are generated by injection of a suprathermal electron beam parallel to the magnetic field in a laboratory plasma. Electric microprobes with tips smaller than the Debye length (λ De ) enabled the measurement of positive potential pulses with half-widths 4 to 25λ De and velocities 1 to 3 times the background electron thermal speed. Nonlinear wave packets of similar velocities and scales are also observed, indicating that the two descend from the same mode which is consistent with the electrostatic whistler mode and result from an instability likely to be driven by field-aligned currents.

Filamentation of a converging heavy ion beam

International Nuclear Information System (INIS)

Lee, E.P.; Buchanan, H.L.; Rosenbluth, M.N.

1980-01-01

A major concern in the use of heavy ion beams as igniters in pellet fusion systems is the vulnerability of the beam to the transverse flamentation instability. The undesirable consequence of this mode is the transverse heating of the beam to the extent that convergence on the pellet becomes impossible. This work considers the case of a beam injected into a gas filled reactor vessel, where finite pulse length and propagation distance play an important role in limiting growth. Two geometries are analyzed: a nonconverging case where the radius at injection is nearly equal to the desired radius at the pellet, and a converging case in which the injection radius is large and the beam is pre-focused to converge at the target. It is found that a cold beam will be severely disrupted if the product of the magnetic plasma frequency and the propagation distance is much larger than unity

Beam Instrumentation of the PXIE LEBT Beamline

Energy Technology Data Exchange (ETDEWEB)

D' Arcy, R. [Fermilab; Hanna, B. [Fermilab; Prost, L. [Fermilab; Scarpine, v. [Fermilab; Shemyakin, A. [Fermilab

2015-06-01

The PXIE accelerator [1] is the front-end test stand of the proposed Proton Improvement Plan (PIP-II) [2] initiative: a CW-compatible pulsed H- superconducting RF linac upgrade to Fermilab’s injection system. The PXIE Ion Source and Low-Energy Beam Transport (LEBT) section are designed to create and transfer a 1-10 mA $H^{-}$ beam, in either pulsed (0.001–16 ms) or DC mode, from the ion source through to the injection point of the RFQ. This paper discusses the range of diagnostic tools – Allison-type Emittance Scanner, Faraday Cup, Toroid, DCCT, electrically isolated diaphragms – involved in the commissioning of the beam line and preparation of the beam for injection into the RFQ.

Shielding considerations for neutral-beam injection systems

International Nuclear Information System (INIS)

de Seynes, X.

1983-03-01

Results of a study on the geometry of an FED-A Neutral Beam Injector beamline duct shield are presented. Also included is a calculation of dose rates, as a function of time, from an activated NBI. The shielding investigations consisted of varying the parameters of the geometry and transporting particles through it using the MCNP Monte-Carlo code. The dose rates were calculated by the ACDOS3 code using realistic MCNP results. A final-to-incident flux ratio of 6.5 x 10 -7 can be achieved through the use of a 65.5 cm reentry duct. This is for a realistic source and pure water shielding material. The activated NBI produced a dose rate of 15.9 mrem/hr two and a half days after shutdown of the reactor

Beam-beam effects for the PEP-II B Factory

International Nuclear Information System (INIS)

Furman, M.A.; Eden, J.R.

1993-05-01

We present a summary of a fairly extensive study of beam-beam issues that arise in the design of PEP-II. Most of these studies are carried out with ''strong-strong'' multiparticle tracking simulations. We focus on: choice of nominal beam-beam parameter, strength of the parasitic collisions, injection issues, performance and tradeoffs with unequal beam-beam parameters. We comment only briefly on beam lifetime. We conclude that: the beams are sufficiently well separated so that the parasitic collisions are effectively weak; that small inequalities in the beam-beam parameters may imply more comfortable performance margins; and that vertical injection with vertical beam separation is more comfortable than horizontal

Power deposition by neutral beam injected fast ions in field-reversed configurations

International Nuclear Information System (INIS)

Takahashi, Toshiki; Kato, Takayuki; Kondoh, Yoshiomi; Iwasawa, Naotaka

2004-01-01

The effects of Coulomb collisions on neutral beam (NB) injected fast ions into field-reversed configuration (FRC) plasmas are investigated by calculating the single particle orbits, where the ions are subject to the slowing-down and pitch-angle collisions. The Monte Carlo method is used for the pitch-angle scattering, and the friction term is added to the equation of motion to show the effects of the slowing-down collision, such as the deposited power profile. The calculation parameters used are relevant to the NB injection on the FRC injection experiment device [T. Asai, Y. Suzuki, T. Yoneda, F. Kodera, M. Okubo, and S. Goto, Phys. Plasmas 7, 2294 (2000)]. It is found that the dominant local power deposition occurs in the open field region between the X point and the mirror point because of a concentration of fast ions and a longer duration travel at the mirror reflection point. In the present calculation, the maximum deposited power to the FRC plasma is about 10% of the injected power. Although the pitch-angle scattering by Coulomb collision destroys the mirror confinement of NB injected fast ions, this effect is found to be negligible. The loss mechanism due to nonadiabatic fast ion motion, which is intrinsic in nonuniform FRC plasmas, has a much greater effect than the pitch-angle scattering by Coulomb collision

LHC Report: Towards stable beams and collisions

CERN Multimedia

CERN Bulletin

2011-01-01

Over the past two weeks, the LHC re-commissioning with beam has continued at a brisk pace. The first collisions of 2011 were produced on 2 March, with stable beams and collisions for physics planned for the coming days. Low intensity beams with just a few bunches of particles were used to test the energy ramp to 3.5 TeV and the squeeze. The results were successful and, as a by-product, the first collisions of 2011 were recorded 2 March. One of the main activities carried out by the operation teams has been the careful set-up of the collimation system, and the injection and beam dump protection devices. The collimation system provides essential beam cleaning, preventing stray particles from impacting other elements of the machine, particularly the superconducting magnets. In addition to the collimation system, also the injection and beam dump protection devices perform a vital machine protection role, as they detect any beam that might be mis-directed during rare, but not totally unavoidable, hardware hiccups...

Observations of ELM stabilization during neutral beam injection in DIII-D

Science.gov (United States)

Bortolon, Alessandro; Kramer, Gerrit; Diallo, Ahmed; Knolker, Matthias; Maingi, Rajesh; Nazikian, Raffi; Degrassie, John; Osborne, Thomas

2017-10-01

Edge localized modes (ELMs) are generally interpreted as peeling-ballooning instabilities, driven by the pedestal current and pressure gradient, with other subdominant effects possibly relevant close to marginal stability. We report observations of transient stabilization of type-I ELMs during neutral beam injection (NBI), emerging from a combined dataset of DIII-D ELMy H-mode plasmas with moderate heating obtained through pulsed NBI waveforms. Statistical analysis of ELM onset times indicates that, in the selected dataset, the likelihood of onset of an ELM lowers significantly during NBI modulation pulses, with the stronger correlation found with counter-current NBI. The effect is also found in rf-heated H-modes, where ELMs appear inhibited when isolated diagnostic beam pulses are applied. Coherent average analysis is used to determine how plasma density, temperature, rotation as well as beam ion quantities evolve during a NB modulation cycle, finding relatively small changes ( 3%) of pedestal Te and ne and toroidal and poloidal rotation variations up to 5 km/s. The effect of these changes on pedestal stability will be discussed. Work supported by US DOE under DE-FC02-04ER54698, DE-AC02-09CH11466.

Confinement studies during neutral beam injection in PLT

International Nuclear Information System (INIS)

Goldston, R.; Davis, S.; Eubank, H.

1980-12-01

Neutral beam injection experiments on PLT have provided definitive information on ion energy confinement in highly collisionless plasmas. We find that ion thermal conduction is consistent, within a factor of approx. 3, with neoclassical theory, and that anomalous thermal convection of ion energy is a factor of 2-3 less than would be calculated from the INTOR D/sub e/ with a convection loss term of the form 5/2nkTv/sub r/. From our experiments with a shunted TF coil we have found that a single shallow ripple well of 2.5% has a neglible effect on ion energy confinement, even at the lowest collisionality obtainable on PLT. Scrutiny of the analytic theories of ripple induced transport motivated by these experiments, suggests that more theoretical (and perhaps numerical) work is needed in this area

Formation of a single-bunch beam in the booster synchrotron at SPring-8

CERN Document Server

Suzuki, H; Ego, H; Hara, M; Hosoda, N; Kawashima, Y; Ohashi, Y; Ohshima, T; Tani, N; Yabashi, M; Yonehara, H

2000-01-01

In order to fill a radio frequency (rf) bucket with an electron beam in the storage ring at SPring-8, an rf knockout system was installed in the booster synchrotron. With this system, the energy of the electron beam injected from the linac was increased from 1 to 8 GeV. The time width of multi-bunch beams from the linac operated at 2856 MHz rf can be selected as 1 or 40 ns. The beam injected from the linac is distributed in rf buckets of the booster synchrotron operated at 508.58 MHz rf. To fill a single rf bucket with a beam, the rf knockout system is operated at a minimum beam energy of 1 GeV. By using the rf knockout system, the electron beam is effectively kept in a single rf bucket. Then the beam is injected into a targeted rf bucket in the storage ring with a precise timing system. The beam intensity of satellite rf buckets in the storage ring was measured with a photon counting method and determined to be 10 sup - sup 6 less than that of the main rf bucket. In this paper, we describe the rf knockout sy...

Optics measurements and transfer line matching for the SPS injection of the CERN Multi-Turn Extraction beam

CERN Document Server

Benedetto, E; Cettour Cave, S; Follin, F; Gilardoni, S; Giovannozzi, M; Roncarolo, F

2010-01-01

Dispersion and beam optics measurements were carried out in the transfer line between the CERN PS and SPS for the new Multi-Turn Extraction beam. Since the extraction conditions of the four islands and the core are different and strongly dependent on the non-linear effects used to split the beam in the transverse plane, a special care was taken during the measurement campaigns. Furthermore, an appropriate strategy was devised to minimize the overall optical mismatch at SPS injection. All this led to a new optical configuration that will be presented in the paper.

LHC Damper Beam commissioning in 2010

CERN Document Server

Höfle, W; Schokker, M; Valuch, D

2011-01-01

The LHC transverse dampers were commissioned in 2010 with beam and their use at injection energy of 450 GeV, during the ramp and in collisions at 3.5 TeV for Physics has become part of the standard operations pro- cedure. The system proved important to limit emittance blow-up at injection and to maintain smaller than nominal emittances throughout the accelerating cycle. We describe the commissioning of the system step-by-step as done in 2010 and summarize its performance as achieved for pro- ton as well as ion beams in 2010. Although its principle function is to keep transverse oscillations under control, the system has also been used as an exciter for abort gap clean- ing and tune measurement. The dedicated beam position measurement system with its low noise properties provides additional possibilities for diagnostics.

High-Energy Beam Transport system

International Nuclear Information System (INIS)

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

1979-01-01

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

Transmission of the Neutral Beam Heating Beams at TJ-II; Transmision del Haz de Neutros de Calentamiento en TJ-II

Energy Technology Data Exchange (ETDEWEB)

Fuentes Lopez, C

2007-09-27

Neutral beam injection heating has been development for the TJ-II stellarator. The beam has a port-through power between 700-1500 kW and injection energy 40 keV. The sensibility of the injection system to the changes of several parameters is analysed. Beam transmission is limited by losses processes since beam is born into the ions source until is coming into the fusion machine. For the beam transmission optimization several beam diagnostics have been developed. A carbon fiber composite (CFC) target calorimeter has been installed at TJ-II to study in situ the power density distribution of the neutral beams. The thermographic print of the beam can be recorded and analysed in a reliable way due to the highly anisotropic thermal conductivity of the target material. With the combined thermographic and calorimetric measurements it has been possible to determine the power density distribution of the beam. It has been found that a large beam halo is present, which can be explained by the extreme misalignment of the grids. This kind of halo has a deleterious effect on beam transport and must be minimized in order to improve the plasma heating capability of the beams. (Author) 155 refs.

FLOC: Field Line and Orbit Code for the study of ripple beam injection into tokamaks

Energy Technology Data Exchange (ETDEWEB)

Fowler, R. H.; Lee, D. K.; Gaffney, P. W.; Rome, J. A.

1978-06-01

The computer code described is used to study ripple beam injection into a tokamak plasma. The collisionless guiding center equations of motion are integrated to find the orbits of single particles in realistic magnetic fields for ripple injection. In order to determine if the ripple is detrimental to the plasma, the magnetic flux surfaces are constructed by integration of the field line equations. The numerical techniques are described, and use of the code is outlined. A program listing is provided, and the results of sample cases are presented.

FLOC: Field Line and Orbit Code for the study of ripple beam injection into tokamaks

International Nuclear Information System (INIS)

Fowler, R.H.; Lee, D.K.; Gaffney, P.W.; Rome, J.A.

1978-06-01

The computer code described is used to study ripple beam injection into a tokamak plasma. The collisionless guiding center equations of motion are integrated to find the orbits of single particles in realistic magnetic fields for ripple injection. In order to determine if the ripple is detrimental to the plasma, the magnetic flux surfaces are constructed by integration of the field line equations. The numerical techniques are described, and use of the code is outlined. A program listing is provided, and the results of sample cases are presented

Mode particle resonances during near-tangential neutral beam injection in large tokamaks

International Nuclear Information System (INIS)

Kaita, R.; White, R.B.; Morris, A.W.; Fredrickson, E.D.; McGuire, K.M.; Medley, S.S.; Scott, S.D.

1988-01-01

Coherent magnetohydrodynamic modes have been observed during neutral beam injection in TFTR and JET. Periodic bursts of oscillations were detected with several plasma diagnostics, and Fokker-Planck calculations show that the populations of trapped particles in both tokamaks are sufficient to account for fishbone destabilization. Estimates of mode parameters are in reasonable agreement with the experiments, and they indicate that the fishbone mode may continue to affect the performance of intensely heated tokamaks. 13 refs., 1 fig., 1 tab

Reliability Analysis of the new Link between the Beam Interlock System and the LHC Beam Dumping System Zuverlässigkeitsanalyse der neuen Verbindung zwischen dem Beam Interlock System und dem LHC Beam Dumping System

CERN Document Server

Vatansever, Volkan

The nominal stored energy in each LHC beam is 360 MJ, surpassing the beam energy of other accelerators by orders of magnitude. This energy threatens to damage accelerator components in case of uncontrolled beam losses To avoid damage of accelerator equipment due to impacting beam, the controlled removal of the LHC beams from the collider rings towards the dump block must be guaranteed at all times. Therefore, the LHC Beam Dumping System was built according to high reliability standards. To further reduce the risk of incapability to dump the beams in case of correlated failures in the redundant system, a new direct link from the LHC Beam Interlock System to the Re-triggering Lines of the LHC Beam Dumping System will be implemented for the startup with beam in 2015. This link represents a diverse redundancy to the current implementation, which should neither significantly increase the risk for so-called Asynchronous Beam Dumps nor compromise machine availability. Therefore, a reliability analysis down to the co...

Fusion Energy Division automation of the ISX-B neutral beams

International Nuclear Information System (INIS)

Bates, S.C.; Hanna, P.C.

1982-06-01

Operation of the two neutral beams on the ISX-B tokamak has been fully automated for an injected power up to 2 MW. A PDP 11/34 FORTRAN program conditions and injects the beams using commercial CAMAC hardware and ad hoc modifications of the beam controls. The fundamental beam conditioning algorithm is based on the breakdown history of the source. Difficulties encountered were noise entering the CAMAC system through control and data lines and the lack of well-defined operating heuristics detailed problem diagnostic techniques. A brief description is given of the hardware and software systems, operating techniques, and items of special concern

Direct energy conversion and neutral beam injection for catalyzed D and D-3He tokamak reactors

International Nuclear Information System (INIS)

Blum, A.S.; Moir, R.W.

1977-01-01

The calculated performance of single stage and Venetian blind direct energy converters for Catalyzed D and D- 3 He Tokamak reactors are discussed. Preliminary results on He pumping are outlined. The efficiency of D and T neutral beam injection is reviewed

PEP-II injection timing and controls

International Nuclear Information System (INIS)

Bharadwaj, V.; Browne, M.; Crane, M.; Gromme, T.; Himel, T.; Ross, M.; Stanek, M.; Ronan, M.

1997-07-01

Hardware has been built and software written and incorporated in the existing SLC accelerator control system to control injection of beam pulses from the accelerator into the PEP-II storage rings currently under construction. Hardware includes a CAMAC module to delay the machine timing fiducial in order that a beam pulse extracted from a damping ring will be injected into a selected group of four 476 MHz buckets in a PEP-II ring. Further timing control is accomplished by shifting the phase of the bunches stored in the damping rings before extraction while leaving the phase of the PEP-II stored beam unchanged. The software which drives timing devices on a pulse-to-pulse basis relies on a dedicated communication link on which one scheduling microprocessor broadcasts a 128-bit message to all distributed control microprocessors at 360 Hz. PEP-II injection will be driven by the scheduling microprocessor according to lists specifying bucket numbers in arbitrary order, and according to scheduling constraints maximizing the useful beam delivered to the SLC collider currently in operation. These lists will be generated by a microprocessor monitoring the current stored per bucket in each of the PEP-II rings

The use of electron beams as probes of the distant magnetosphere

International Nuclear Information System (INIS)

Winckler, J.R.

1982-01-01

This chapter reports on experiments in which electron beams have been injected into the magnetosphere in order to diagnose plasma processes at a great distance by measurements made in the ionosphere. Topics considered include the beam injecting rocket system in the ionosphere; beam detection and analysis; echo detection by particle counters; echo analysis; the structure of echoes; the atmosphere as a detector; radio and radar methods; perturbation of the distant magnetosphere by beam injection; changes in the injected beam in the near-rocket region; some observations of the distant magnetosphere by beams; the comparison of distant and local electric fields; electron diffusion; the distant magnetic field; and future possibilities. Conjugate locations, field line lengths, electric and magnetic drifts, field fluctuations, and electron scattering and diffusion are analyzed. Echo detection by particle counters on some of the ECHO rocket series is discussed in detail

LHC Report: The beam is back at the LHC

CERN Multimedia

Reyes Alemany

2015-01-01

A series of sector beam tests paved the way for the start-up of the LHC in 2008 and 2009. These tests and the follow-up of the issues that arose were part of the process that led to a smooth start-up with beam.   Given this experience, sector tests were scheduled to take place several weeks before the 2015 start-up. On the weekend of 6-9 March, beam from the SPS was injected into both LHC injection regions, followed by a first pass through the downstream LHC sectors. For the clockwise LHC beam (called “beam 1”) this meant passing through ALICE and into Sector 2-3, while the anticlockwise beam (called “beam 2”) was threaded through LHCb and all the way from Point 8 to Point 6, where it was extracted by the beam dump kickers onto the beam dump block. The dry runs in the previous weeks were mainly targeted at preparation for the sector tests. The systems tested included: injection, timing, synchronisation and beam instrumentation. The beam interlock ...

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

International Nuclear Information System (INIS)

Witkover, R.L.

1995-01-01

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

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

International Nuclear Information System (INIS)

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

1989-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

1989-01-01

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

Injection and extraction techniques in circular accelerators

International Nuclear Information System (INIS)

Tang Jingyu

2008-01-01

Injection and extraction are usually the key systems in circular accelerators. They play important roles in transferring the beam from one stage acceleration to the other or to experimental stations. It is also in the injection and extraction regions where beam losses happen mostly. Due to the tight space and to reduce the perturbation to the circulating orbit, the devices are usually designed to meet special requirements such as compactness, small stray field, fast rise time or fall time, etc. Usual injection and extraction devices include septum magnets, kicker magnets, electrostatic deflectors, slow bump magnets and strippers. In spite of different accelerators and specification for the injection and extraction devices, many techniques are shared in the design and manufacturing. This paper gives a general review on the techniques employed in the major circular accelerators in China. (authors)

MTBE and priority contaminant treatment with high energy electron beam injection

Energy Technology Data Exchange (ETDEWEB)

Cooper, William J; Nickelsen, Michael G; Mezyk, Stephen P; Leslie, Greg; Tornatore, Paul M; Hardison, Wayne; Hajali, Paris A

2002-11-01

A study was conducted to examine the removal of methyl tert-butyl ether (MTBE) and 15 other organic compounds, as well as perchlorate ion, in waters of different quality. The 15 organic compounds consisted of halogenated solvents (chlorination), disinfection by-products, pesticides, and nitrosodimethylamine (NDMA). These studies were conducted using a pilot scale 20 kW mobile electron beam system at Water Factory 21, Orange County, CA where wastewater is treated and re-injected into the ground as a barrier to salt water intrusion. Future applications for this treated water include water reuse. Ground water and treated wastewater, after having gone through a reverse osmosis-polishing step (RO permeate), were used to prepare mixtures of the compounds. Using fundamental radiation chemistry, it was possible to examine the factors effecting removal efficiency of all the compounds as well as MTBE destruction and reaction by-product formation and removal. All of the organic compounds were destroyed in the studies and we also observed the destruction of perchlorate ion in one of the waters.

MTBE and priority contaminant treatment with high energy electron beam injection

International Nuclear Information System (INIS)

Cooper, William J.; Nickelsen, Michael G.; Mezyk, Stephen P.; Leslie, Greg; Tornatore, Paul M.; Hardison, Wayne; Hajali, Paris A.

2002-01-01

A study was conducted to examine the removal of methyl tert-butyl ether (MTBE) and 15 other organic compounds, as well as perchlorate ion, in waters of different quality. The 15 organic compounds consisted of halogenated solvents (chlorination), disinfection by-products, pesticides, and nitrosodimethylamine (NDMA). These studies were conducted using a pilot scale 20 kW mobile electron beam system at Water Factory 21, Orange County, CA where wastewater is treated and re-injected into the ground as a barrier to salt water intrusion. Future applications for this treated water include water reuse. Ground water and treated wastewater, after having gone through a reverse osmosis-polishing step (RO permeate), were used to prepare mixtures of the compounds. Using fundamental radiation chemistry, it was possible to examine the factors effecting removal efficiency of all the compounds as well as MTBE destruction and reaction by-product formation and removal. All of the organic compounds were destroyed in the studies and we also observed the destruction of perchlorate ion in one of the waters

ORNL 150 keV neutral beam test facility

International Nuclear Information System (INIS)

Gardner, W.L.; Kim, J.; Menon, M.M.; Schilling, G.

1977-01-01

The 150 keV neutral beam test facility provides for the testing and development of neutral beam injectors and beam systems of the class that will be needed for the Tokamak Fusion Test Reactor (TFTR) and The Next Step (TNS). The test facility can simulate a complete beam line injection system and can provide a wide range of experimental operating conditions. Herein is offered a general description of the facility's capabilities and a discussion of present system performance

Accelerated Electron-Beam Formation with a High Capture Coefficient in a Parallel Coupled Accelerating Structure

Science.gov (United States)

Chernousov, Yu. D.; Shebolaev, I. V.; Ikryanov, I. M.

2018-01-01

An electron beam with a high (close to 100%) coefficient of electron capture into the regime of acceleration has been obtained in a linear electron accelerator based on a parallel coupled slow-wave structure, electron gun with microwave-controlled injection current, and permanent-magnet beam-focusing system. The high capture coefficient was due to the properties of the accelerating structure, beam-focusing system, and electron-injection system. Main characteristics of the proposed systems are presented.

Cooled heavy ion beams at the ESR

International Nuclear Information System (INIS)

Steck, M.; Beckert, K.; Bosch, F.; Eickhoff, H.; Franzke, B.; Klepper, O.; Nolden, F.; Reich, H.; Schlitt, B.; Spaedtke, P.; Winkler, T.

1996-01-01

The storage ring ESR has been used in various operational modes for experiments with electron cooled heavy ion beams. Besides the standard storage mode including injection and beam accumulation the deceleration of highly charged ions has been demonstrated. Beams of highly charged ions have been injected and accumulated and finally decelerated to a minimum energy of 50 MeV/u. An ultraslow extraction method using charge changing processes is now also available for cooled beams of highly charged ions. For in ring experiments the internal gas jet and the cold electron beam of the cooling system are applied as targets. High precision mass spectrometry by Schottky noise detection has been demonstrated. Operation at transition energy has been achieved with cooled beams opening the field for experiments which require an isochronous revolution of the ions. (orig.)

Dynamic neutral beam current and voltage control to improve beam efficacy in tokamaks

Science.gov (United States)

Pace, D. C.; Austin, M. E.; Bardoczi, L.; Collins, C. S.; Crowley, B.; Davis, E.; Du, X.; Ferron, J.; Grierson, B. A.; Heidbrink, W. W.; Holcomb, C. T.; McKee, G. R.; Pawley, C.; Petty, C. C.; Podestà, M.; Rauch, J.; Scoville, J. T.; Spong, D. A.; Thome, K. E.; Van Zeeland, M. A.; Varela, J.; Victor, B.

2018-05-01

An engineering upgrade to the neutral beam system at the DIII-D tokamak [J. L. Luxon, Nucl. Fusion 42, 614 (2002)] enables time-dependent programming of the beam voltage and current. Initial application of this capability involves pre-programmed beam voltage and current injected into plasmas that are known to be susceptible to instabilities that are driven by energetic ( E ≥ 40 keV) beam ions. These instabilities, here all Alfvén eigenmodes (AEs), increase the transport of the beam ions beyond a classical expectation based on particle drifts and collisions. Injecting neutral beam power, P beam ≥ 2 MW, at reduced voltage with increased current reduces the drive for Alfvénic instabilities and results in improved ion confinement. In lower-confinement plasmas, this technique is applied to eliminate the presence of AEs across the mid-radius of the plasmas. Simulations of those plasmas indicate that the mode drive is decreased and the radial extent of the remaining modes is reduced compared to a higher beam voltage case. In higher-confinement plasmas, this technique reduces AE activity in the far edge and results in an interesting scenario of beam current drive improving as the beam voltage reduces from 80 kV to 65 kV.

Remote systems requirements of the high-yield lithium injection fusion energy converter concept

International Nuclear Information System (INIS)

Walker, P.E.

1978-01-01

Remote systems will be required in the high-yield lithium injection fusion energy converter power plant proposed by Lawrence Livermore Laboratory. During inspection operations, viewing of the chamber interior and certain pumps, valve fittings, and welds must be done remotely. Ideas for remote maintenance of laser-beam blast baffles, optics, and target material traps are described. Radioisotope sources, their distributions, and exposure rates at various points in the reactor vicinity are presented

Study on improvement of the lifetime of a field-reversed configuration by tangential neutron beam injection

International Nuclear Information System (INIS)

Takahashi, Toshiki; Kondoh, Yoshiomi; Hirano, Yoichi; Asai, Tomohiko; Takahashi, Tsutomu; Mizuguchi, Naoki; Tomita, Yukihiro

2006-01-01

The numerical analysis of neutron beam injection (NBI) is carried out to keep the stationary conditions of the field-reversed configuration (FRC) plasma. The ionization process of neutron beam was reproduced by the Monte Carlo method. A confinement of 15 keV beam ion was investigated using the sharp of stormer region obtained by the position and velocity at a moment of ionization. The relation between the external magnetic field B ex [T] and radius of machine r w [m] was shown by B ex = 0.1 r w -3/4 . The power imparted to plasma was estimated by beam ion orbital calculation. The confinement coefficient of beam ion was lost by re-charge-exchange reaction with deuterium; this fact was discovered at first. In order to keep the configuration of plasma under the conditions of 0.2 T of the external magnetic field, 0.4 m of radius, and 100 eV ion temperature, about 17 MW/m NBI power is needed. (S.Y.)

Upgrade of the LHC Injection Kicker Magnets

CERN Document Server

Barnes, M J; Baglin, V; Bregliozzi, G; Caspers, F; Calatroni, S; Day, H; Ducimetière, L; Garlaschè, M; Gomes Namora, V; Jimenez, J M; Magnin, N; Mertens, V; Métral, E; Salvant, B; Taborelli, M; Uythoven, J; Weterings, W

2013-01-01

Two LHC injection kicker systems, each comprising 4 magnets per ring, produce a kick of 1.3 T·m with a rise-time of less than 900 ns and a flattop ripple of less than ±0.5%. A beam screen is placed in the aperture of each magnet, to provide a path for the image current of the LHC beam and screen the ferrite yoke against wake fields. The screen consists of a ceramic tube with conductors in the inner wall. The initially implemented beam screen ensured a low rate of electrical breakdowns and an adequately low beam coupling impedance. Operation with increasingly higher intensity beams, stable for many hours at a time, has resulted in substantial heating of the ferrite yoke, sometimes requiring cool-down over several hours before the LHC can be refilled. During the long shutdown in 2013/2014 all eight kicker magnets will be upgraded with an improved beam screen and an increased emissivity of the vacuum tank. In addition equipment adjacent to the injection kickers and various vacuum components will be modified to...

Injection quality measurements with diamond based particle detectors

CERN Document Server

Stein, Oliver; CERN. Geneva. ATS Department

2016-01-01

During the re-commissioning phase of the LHC after the long shutdown 1 very high beam losses were observed at the TDI during beam injection. The losses reached up to 90% of the dump threshold. To decrease the through beam losses induced stress on the accelerator components these loss levels need to be reduced. Measurements with diamond based particle detectors (dBLMs), which have nano-second time resolution, revealed that the majority of these losses come from recaptured SPS beam surrounding the nominal bunch train. In this MD the injection loss patterns and loss intensities were investigated in greater detail. Performed calibration shots on the TDI (internal beam absorber for injection) gave a conversion factor from impacting particles intensities to signal in the dBLMs (0.1Vs/109 protons). Using the SPS tune kicker for cleaning the recaptured beam in the SPS and changing the LHC injection kicker settings resulted in a reduction of the injection losses. For 144 bunch injections the loss levels were decreased...

High power 1 MeV neutral beam system and its application plan for the international tokamak experimental reactor

Energy Technology Data Exchange (ETDEWEB)

Hemsworth, R S [ITER Joint Central Team, Naka, Ibaraki (Japan)

1997-03-01

This paper describes the Neutral Beam Injection system which is presently being designed for the International Tokamak Experimental Reactor, ITER, in Europe Japan and Russia, with co-ordination by the Joint Central Team of ITER at Naka, Japan. The proposed system consists of three negative ion based neutral injectors, delivering a total of 50 MW of 1 MeV D{sup 0} to the ITER plasma for a pulse length of >1000 s. Each injectors uses a single caesiated volume arc discharge negative ion source, and a multi-grid, multi-aperture accelerator, to produce about 40 A of 1 MeV D{sup -}. This will be neutralized by collisions with D{sub 2} in a sub-divided gas neutralizer, which has a conversion efficiency of about 60%. The charged fraction of the beam emerging from the neutralizer is dumped in an electrostatic residual ion dump. A water cooled calorimeter can be moved into the beam path to intercept the neutral beam, allowing commissioning of the injector independent of ITER. ITER is scheduled to produce its first plasma at the beginning of 2008, and the planning of the R and D, construction and installation foresees the neutral injection system being available from the start of ITER operations. (author)

Performance of the PDX neutral beam wall armor

International Nuclear Information System (INIS)

Kugel, H.W.; Eubank, H.P.; Kozub, T.A.; Williams, M.D.

1985-02-01

The PDX wall armor was designed to function as an inner wall thermal armor, a neutral beam diagnostic, and a large area inner toroidal plasma limiter. In this paper we discuss its thermal performance as wall armor during two years of PDX neutral beam heating experiments. During this period it provided sufficient inner wall protection to permit perpendicular heating injections into normal and disruptive plasmas as well as injections in the absence of plasma involving special experiments, calibrations, and tests important for the optimization and development of the PDX neutral beam injection system. Many of the design constraints and performance issues encountered in this work are relevant to the design of larger fusion devices

Dual fuel injection piggyback controller system

Science.gov (United States)

Muji, Siti Zarina Mohd.; Hassanal, Muhammad Amirul Hafeez; Lee, Chua King; Fawzi, Mas; Zulkifli, Fathul Hakim

2017-09-01

Dual-fuel injection is an effort to reduce the dependency on diesel and gasoline fuel. Generally, there are two approaches to implement the dual-fuel injection in car system. The first approach is changing the whole injector of the car engine, the consequence is excessive high cost. Alternatively, it also can be achieved by manipulating the system's control signal especially the Electronic Control Unit (ECU) signal. Hence, the study focuses to develop a dual injection timing controller system that likely adopted to control injection time and quantity of compressed natural gas (CNG) and diesel fuel. In this system, Raspberry Pi 3 reacts as main controller unit to receive ECU signal, analyze it and then manipulate its duty cycle to be fed into the Electronic Driver Unit (EDU). The manipulation has changed the duty cycle to two pulses instead of single pulse. A particular pulse mainly used to control injection of diesel fuel and another pulse controls injection of Compressed Natural Gas (CNG). The test indicated promising results that the system can be implemented in the car as piggyback system. This article, which was originally published online on 14 September 2017, contained an error in the acknowledgment section. The corrected acknowledgment appears in the Corrigendum attached to the pdf.

An analysis of the SCEX 3 ionospheric electron beam injection experiment

International Nuclear Information System (INIS)

Goerke, R.T.

1992-01-01

The SCEX 3 experiment (Several Compatible EXperiments using a rocket-borne accelerator) was carried to ionospheric altitudes (375 km) by a Black Brant 11 rocket on February 1, 1990. The experiment was launched from Poker Flat Research Range (65.1 degree N, 147.5 degree W) at 1207 UT. The payload split into two parts (hereafter forward and aft payloads) 116 seconds after launch. The aft payload carried two electron accelerators as well as several diagnostic instruments. The forward payload was ejected at an angle of 6 degree with the magnetic field in a northwesterly direction. This payload carried a multiband plasma wave receiver and various particle detectors to make in situ measurements of the Beam Plasma Interaction (BPI) region. Two Throw Away Detectors (TAD's 1 and 2) were also ejected from the aft payload in the east and west directions respectively. TAD 1 also carried a multiband plasma wave receiver. Preceding the launch an auroral arch along the southern boundary of a diffuse auroral patch suddenly brightened, split into two separate arcs and moved to a position north of the rocket's trajectory. SCEX 3 was launched into an active breakup aurora consisting of tall rays and diffuse patches. The purpose of this experiment were (1) to observe injected electrons reflected from the naturally occurring parallel electric field structures which are thought to accelerate the auroral electron, (2) to observe a variety of plasma effects caused by the artificial electron beam and the associated spacecraft charging, and (3) study the natural phenomena associated with auroral activity. This work is a summary of the interesting observations made by the SCEX 3 experiment. These observations include VHF emissions produced by the electron beam via the Beam Plasma Discharge (BPD), Diffuse resonance emissions by the hot plasma region surrounding the electron beam and auroral Z-mode emissions

Computer system for the beam line data processing at JT-60 prototype neutral beam injector

International Nuclear Information System (INIS)

Horiike, Hiroshi; Kawai, Mikito; Ohara, Yoshihiro

1987-08-01

The present report describes the hard and soft wares of the data acquisition computer system for the prototype neutral injector unit for JT-60. In order to operate the unit, more than hundreds of signals of the beam line components have to be measured. These are mainly differential thermometers for the coolant waters and thermocouples for the beam dump components but not include those for the cryo system. Since the unit operates in a series of pulses, the measurement should be conducted very quickly in order to ensure the simultaneity of large number of the measured data. The present system actualize fast data acquisition using a small computer of 128 kB and measuring instruments connected through the bus. The system is connected to the JAERI computer center since the data capacity is fairly large to completely process them by the small computer. Therefore the measured data can be transferred to the computer center to calculate there, and the results can be received. After the system was completed the computer quickly print out the power flow data, which needed much work to calculate with hands. This system was very useful. It enhanced the experiments at the unit and reduced the labor. It enables us to early demonstrate the rated operation of the unit and to accurately estimate such operation data of the JT-60 NBI as the injection power. (author)

Beam-driven currents in the 1/ν regime in a helical system

International Nuclear Information System (INIS)

Nakajima, Noriyoshi; Okamoto, Masao.

1990-04-01

Beam currents driven by a neutral particle injection in a helical system (stellarator, heliotron/torsatron) are studied in the 1/ν collisionality regime. The general expression for the beam-driven current is obtained for arbitrary magnetic field configurations by solving the drift kinetic equation for electrons. It is found that F = J(net)/J(b) (J(net) is the net current and J(b) is the fast ion beam current) increases as f(t) and Zeff where f(t) is the fraction of trapped electrons and Zeff is the effective ionic charge number. Especially, for Zeff ≅ 1 the effect of trapped electrons is large and F is roughly proportional to f(t). On the other hand, if Zeff > or approx 3 the effect of trapped electrons becomes small. (author)

Electron and ion heat transport with lower hybrid current drive and neutral beam injection heating in ASDEX

International Nuclear Information System (INIS)

Soeldner, F.X.; Pereverzev, G.V.; Bartiromo, R.; Fahrbach, H.U.; Leuterer, F.; Murmann, H.D.; Staebler, A.; Steuer, K.H.

1993-01-01

Transport code calculations were made for experiments with the combined operation of lower hybrid current drive and heating and of neutral beam injection heating on ASDEX. Peaking or flattening of the electron temperature profile are mainly explained by modifications of the MHD induced electron heat transport. They originate from current profile changes due to lower hybrid and neutral beam current drive and to contributions from the bootstrap current. Ion heat transport cannot be described by one single model for all heating scenarios. The ion heat conductivity is reduced during lower hybrid heated phases with respect to Ohmic and neutral beam heating. (author). 13 refs, 5 figs

Modeling and control of plasma rotation for NSTX using neoclassical toroidal viscosity and neutral beam injection

Energy Technology Data Exchange (ETDEWEB)

Goumiri, I. R. [Princeton Univ., NJ (United States). Mechanical and Aerospace Dept.; Rowley, C. W. [Princeton Univ., NJ (United States). Mechanical and Aerospace Dept.; Sabbagh, S. A. [Columbia Univ., New York, NY (United States). Dept. of Applied Physics and Applied Mathematics; Gates, D. A. [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); Gerhardt, S. P. [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); Boyer, M. D. [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); Andre, R. [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); Kolemen, E. [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); Taira, K. [Florida State Univ, Dept Mech Engn, Tallahassee, FL USA.

2016-02-19

A model-based feedback system is presented to control plasma rotation in a magnetically confined toroidal fusion device, to maintain plasma stability for long-pulse operation. This research uses experimental measurements from the National Spherical Torus Experiment (NSTX) and is aimed at controlling plasma rotation using two different types of actuation: momentum from injected neutral beams and neoclassical toroidal viscosity generated by three-dimensional applied magnetic fields. Based on the data-driven model obtained, a feedback controller is designed, and predictive simulations using the TRANSP plasma transport code show that the controller is able to attain desired plasma rotation profiles given practical constraints on the actuators and the available measurements of rotation.

Beam loss caused by edge focusing of injection bump magnets and its mitigation in the 3-GeV rapid cycling synchrotron of the Japan Proton Accelerator Research Complex

Directory of Open Access Journals (Sweden)

H. Hotchi

2016-01-01

Full Text Available In the 3-GeV rapid cycling synchrotron of the Japan Proton Accelerator Research Complex, transverse injection painting is utilized not only to suppress space-charge induced beam loss in the low energy region but also to mitigate foil scattering beam loss during charge-exchange injection. The space-charge induced beam loss is well minimized by the combination of modest transverse painting and full longitudinal painting. But, for sufficiently mitigating the foil scattering part of beam loss, the transverse painting area has to be further expanded. However, such a wide-ranging transverse painting had not been realized until recently due to beta function beating caused by edge focusing of pulsed injection bump magnets during injection. This beta function beating additionally excites random betatron resonances through a distortion of the lattice superperiodicity, and its resultant deterioration of the betatron motion stability causes significant extra beam loss when expanding the transverse painting area. To solve this issue, we newly installed pulse-type quadrupole correctors to compensate the beta function beating. This paper presents recent experimental results on this correction scheme for suppressing the extra beam loss, while discussing the beam loss and its mitigation mechanisms with the corresponding numerical simulations.

Novel technique for injecting and extracting beams in a circular hadron accelerator without using septum magnets

Directory of Open Access Journals (Sweden)

Andrea Franchi

2015-07-01

Full Text Available With a few exceptions, all on-axis injection and extraction schemes implemented in circular particle accelerators, synchrotrons, and storage rings, make use of magnetic and electrostatic septa with systems of slow-pulsing dipoles acting on tens of thousands of turns and fast-pulsing dipoles on just a few. The dipoles create a closed orbit deformation around the septa, usually referred to as an orbit bump. A new approach is presented which obviates the need for the septum deflectors. Fast-pulsing elements are still required, but their strength can be minimized by choosing appropriate local accelerator optics. This technique should increase the beam clearance and reduce the usually high radiation levels found around the septa and also reduce the machine impedance introduced by the fast-pulsing dipoles. The basis of the technique is the creation of stable islands around stable fixed points in horizontal phase space. The trajectories of these islands may then be adjusted to match the position and angle of the incoming or outgoing beam.

Magnetically insulated transmission line used for relativistic electron beam injection into SPAC-VI

International Nuclear Information System (INIS)

Tsuzuki, Tetsuya; Narihara, Kazumichi; Tomita, Yukihiro; Mohri, Akihiro.

1980-10-01

For the purpose to inject the electron beam with energy of about 1.5 MeV and current of about 100 kA into the SPAC-6 (torus device), a magnetically insulated transmission line was designed and constructed. The motion of electrons in the line was theoretically analyzed. The requirements for the design of the transmission line were as follows-: (a) condition of magnetic insulation, (b) suppression against reverse gas flow from the beam source to the torus, (c) care to minimize the influence of strong torus magnetic field, (d) reduction of inductance and (e) safety engineering measures, e.g., separation valve in the MITL between the beam source and the SPAC-6. The transmission line of 2.4 m long was designed and constructed. The wave forms of electric potential and current were measured. The transmission efficiency of current along the axis and the efficiency as a function of current at the end of the line were also measured. The reason of the loss of current is discussed. (J.P.N.)

Injection Related Background due to the Transverse Feedback

International Nuclear Information System (INIS)

Decker, F.J.; Akre, R.; Fisher, A.; Iverson, R.; Weaver, M.

2008-01-01

The background in the BaBar detector is especially high during injection, when most components are actually having reduced voltages. The situation is worse for the beam in High Energy Ring (HER) when the LER beam is present. It was found that the transverse feedback system plays an important role when stacking more charge on top of existing bunches. Lowering the feedback gain helped and it was realized later that the best scenario would be to gate off the feedback for only the one bunch, which got additional charge injected into it. The explanation is that the blown-up, but centered, original HER bunch plus the small injected off-axis bunch (each with half the charge) would stay in the ring if not touched, but the feedback system sees half the offset and wants to correct it, therefore disturbing and scraping the blown-up part

A description of the ITER's gas injection systems and current R and D activities

International Nuclear Information System (INIS)

Li, W.; Li, B.; Maruyama, S.; Jiang, T.; Yang, Y.; Xia, Z.W.; Zhang, Y.X.; Lu, J.

2012-01-01

The gas injection system (GIS) is an indispensable part of ITER fueling system. It deliveries the necessary gas species from tritium plant to vacuum vessel, pellet injection system or neutral beam for plasma operation and fusion power shutdown. In this paper, the current design status of GIS, including the previous design changes, is briefly described. As the GIS design justification and support, the experimental study on GIS response time is illustrated. The factors delayed the GIS response time are identified, and two kinds of control mode are proved to be effective for improving the GIS response time. The exploration on magnetic shield design shows the discrepancy of shielding performance occurs in the case of the paralleling external magnetic field to the sample cylinder. These R and D works prove the design feasibility in some ways, and support possible solutions for design challenges as alternative design options.

A volumetric flow sensor for automotive injection systems

International Nuclear Information System (INIS)

Schmid, U; Krötz, G; Schmitt-Landsiedel, D

2008-01-01

For further optimization of the automotive power train of diesel engines, advanced combustion processes require a highly flexible injection system, provided e.g. by the common rail (CR) injection technique. In the past, the feasibility to implement injection nozzle volumetric flow sensors based on the thermo-resistive measurement principle has been demonstrated up to injection pressures of 135 MPa (1350 bar). To evaluate the transient behaviour of the system-integrated flow sensors as well as an injection amount indicator used as a reference method, hydraulic simulations on the system level are performed for a CR injection system. Experimentally determined injection timings were found to be in good agreement with calculated values, especially for the novel sensing element which is directly implemented into the hydraulic system. For the first time pressure oscillations occurring after termination of the injection pulse, predicted theoretically, could be verified directly in the nozzle. In addition, the injected amount of fuel is monitored with the highest resolution ever reported in the literature

A volumetric flow sensor for automotive injection systems

Science.gov (United States)

Schmid, U.; Krötz, G.; Schmitt-Landsiedel, D.

2008-04-01

For further optimization of the automotive power train of diesel engines, advanced combustion processes require a highly flexible injection system, provided e.g. by the common rail (CR) injection technique. In the past, the feasibility to implement injection nozzle volumetric flow sensors based on the thermo-resistive measurement principle has been demonstrated up to injection pressures of 135 MPa (1350 bar). To evaluate the transient behaviour of the system-integrated flow sensors as well as an injection amount indicator used as a reference method, hydraulic simulations on the system level are performed for a CR injection system. Experimentally determined injection timings were found to be in good agreement with calculated values, especially for the novel sensing element which is directly implemented into the hydraulic system. For the first time pressure oscillations occurring after termination of the injection pulse, predicted theoretically, could be verified directly in the nozzle. In addition, the injected amount of fuel is monitored with the highest resolution ever reported in the literature.

Measurement of neutral beam power and beam profile distribution on DNB

International Nuclear Information System (INIS)

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

2005-01-01

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

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

International Nuclear Information System (INIS)

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

1979-01-01

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

Status of the 160 MeV H- Injection into the CERN PSB

CERN Document Server

Weterings, W; Benedetto, E; Borburgh, J; Bracco, C; Carli, C; Goddard, B; Hanke, K; Mikulec, B; Newborough, A; Noulibos, R; Tan, J

2012-01-01

The 160 MeV H- beam from the LINAC4 will be injected into the 4 superimposed rings of the PS Booster (PSB) with a new H- charge-exchange injection system. This entails a massive upgrade of the injection region. The hardware requirements and constraints, the performance specifications and the design of the H- injection region are described.

CONCEPTUAL DESIGN OF THE NSLS-II INJECTION SYSTEM.

Energy Technology Data Exchange (ETDEWEB)

SHAFTAN,T.; ROSE, T.; PINAYEV, I.; HEESE, R.; BENGTSSON, J.; SKARITKA, J.; MENG, W.; OZAKI, S.; MEIER, R.; STELMACH, C.; LITVINENKO, V.; PJEROV, S.; SHARMA, S.; GANETIS, G.; HSEUH, H.C.; JOHNSON, E.D.; TSOUPAS, N.; GUO, W.; BEEBE-WANG, J.; LUCCIO, A.U.; YU, L.H.; RAPARIA, D.; WANG, D.

2007-06-25

We present the conceptual design of the NSLS-II injection system [1,2]. The injection system consists of a low-energy linac, booster and transport lines. We review two different injection system configurations; a booster located in the storage ring tunnel and a booster housed in a separate building. We briefly discuss main parameters and layout of the injection system components.

TRANSVERSE PHASE SPACE PAINTING FOR SNS ACCUMULATOR RING INJECTION.

Energy Technology Data Exchange (ETDEWEB)

BEEBE-WANG,J.; LEE,Y.Y.; RAPARIA,D.; WEI,J.

1999-03-29

The result of investigation and comparison of a series of transverse phase space painting schemes for the injection of SNS accumulator ring [1] is reported. In this computer simulation study, the focus is on the creation of closed orbit bumps that give desired distributions at the target. Space charge effects such as tune shift, emittance growth and beam losses are considered. The results of pseudo end-to-end simulations from the injection to the target through the accumulator ring and Ring to Target Beam Transfer (RTBT) system [2] are presented and discussed.

The LHC injection kicker magnet

CERN Document Server

Ducimetière, Laurent; Barnes, M J; Wait, G D

2003-01-01

Proton beams will be injected into LHC at 450 GeV by two kicker magnet systems, producing magnetic field pulses of approximately 900 ns rise time and up to 7.86 s flat top duration. One of the stringent design requirements of these systems is a flat top ripple of less than ± 0.5%. Both injection systems are composed of 4 travelling wave kicker magnets of 2.7 m length each, powered by pulse forming networks (PFN's). To achieve the required kick strength of 1.2 Tm, a low characteristic impedance has been chosen and ceramic plate capacitors are used to obtain 5 Omega. Conductive stripes in the aperture of the magnets limit the beam impedance and screen the ferrite. The electrical circuit has been designed with the help of PSpice computer modelling. A full size magnet prototype has been built and tested up to 60 kV with the magnet under ultra high vacuum (UHV). The pulse shape has been precision measured at a voltage of 15 kV. After reviewing the performance requirements the paper presents the magnet...

Remote systems requirements of the High Yield Lithium Injection Fusion Energy (HYLIFE) converter concept

International Nuclear Information System (INIS)

Walker, P.E.

1978-10-01

Remote systems will be required in the High Yield Lithium Injection Fusion Energy Converter power plant proposed by Lawrence Livermore Laboratory. During inspection operations, viewing of the chamber interior and certain pumps, valve fittings and welds must be done remotely. Ideas for remote maintenance of laser beam blast baffles, optics, and target material traps are described. Radioisotope sources and their distributions, and exposure rates at various points in the reactor vicinity are presented

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

International Nuclear Information System (INIS)

Anon.

1978-01-01

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

Phase measurement and control of bunched beams

International Nuclear Information System (INIS)

Lewis, R.N.

1978-01-01

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

Injection and lessons for 2012

International Nuclear Information System (INIS)

Bracco, C.; Barnes, M.J.; Bartmann, W.; Cornelis, K.; Drosdal, L.N.; Goddard, B.; Kain, V.; Meddahi, M.; Mertens, V.; Uythoven, J.

2012-01-01

Injection of 144 bunches into the LHC became fully operational during the 2011 run and one nominal injection of 288 bunches was accomplished. Several mitigation solutions were put in place to minimise losses from the Transfer Line (TL) collimators and losses from kicking de-bunched beam during injection. Nevertheless, shot-by- shot and bunch-by-bunch trajectory variations, as well as long terms drifts, were observed and required a regular re-steering of the TL implying a non negligible amount of time spent for injection setup. Likely sources of instability have been identified (i.e. MKE and MSE ripples) and possible cures to optimise 2012 operation are presented. Well defined references for TL steering will be defined in a more rigorous way in order to allow a more straightforward and faster injection setup. Encountered and potential issues of the injection system, in particular the injection kickers MKI, are discussed also in view of injections with a higher number of bunches. (authors)

Injection and lessons for 2012

CERN Document Server

Bracco, C; Bartmann, W; Cornelis, K; Drosdal, L N; Goddard, B; Kain, V; Meddahi, M; Mertens, V; Uythoven, J

2012-01-01

Injection of 144 bunches into the LHC became fully operational during the 2011 run and a nominal injection of 288 bunches was accomplished during MD time. Several mitigation solutions were put in place to minimise losses from the transfer line (TL) collimators and losses from kicking debunched beam during injection. Nevertheless, shot-by-shot and bunch-by-bunch trajectory variations, as well as long terms drifts, were observed and required a regular resteering of the TL implying a non negligible amount of time spent for injection setup. Likely sources of instability have been identified (i.e. MKE and MSE ripples) and possible cures to optimise 2012 operation are presented. Well defined references for TL steering will be defined in a more rigorous way in order to allow a more straightforward and faster injection setup. Encountered and potential issues of the injection system, in particular the injection kickers MKI, are discussed also in view of injections with a higher number of bunches.

Dual Power Supplies for PEP-II Injection Kickers

CERN Document Server

Olszewski, Joseph; Iverson, Richard; Kulikov, Artem; Pappas, Chris

2005-01-01

Originally the PEP-II injection kickers where powered by one power supply. Since the kicker magnets where not perfectly matched, the stored beam got excited by about 7% of the maximum kicker amplitude. This led to luminosity losses which were especially obvious for trickle injection when the detector is on for data taking. Therefore two independant power supplies with thyratrons in the tunnel next to the kicker magnet were installed. This also reduces the necessary power by about a factor of five since there are no long cables that have to be charged. The kickers are now independantly adjustable to eliminate any non-closure of the kicker system and therefore excitation of the stored beam. Setup, commissioning and fine tuning of this system are discussed.

Dual Power Supplies for PEP-II Injection Kickers

Energy Technology Data Exchange (ETDEWEB)

Olszewski, J; Decker, F.-J.; Iverson, R.H.; Kulikov, A.; Pappas, C.; /SLAC

2005-05-25

Originally the PEP-II injection kickers were powered by one power supply. Since the kicker magnets where not perfectly matched, the stored beam got excited by about 7% of the maximum kicker amplitude. This led to luminosity losses which were especially obvious for trickle injection when the detector is on for data taking. Therefore two independent power supplies with thyratrons in the tunnel next to the kicker magnet were installed. This also reduces the necessary power by about a factor of four since there are no long cables that have to be charged. The kickers are now independently adjustable to eliminate any non-closure of the kicker system and therefore excitation of the stored beam. Setup, commissioning and fine tuning of this system are discussed.

Dual Power Supplies for PEP-II Injection Kickers

International Nuclear Information System (INIS)

Olszewski, J; Decker, F.-J.; Iverson, R.H.; Kulikov, A.; Pappas, C.; SLAC

2005-01-01

Originally the PEP-II injection kickers were powered by one power supply. Since the kicker magnets where not perfectly matched, the stored beam got excited by about 7% of the maximum kicker amplitude. This led to luminosity losses which were especially obvious for trickle injection when the detector is on for data taking. Therefore two independent power supplies with thyratrons in the tunnel next to the kicker magnet were installed. This also reduces the necessary power by about a factor of four since there are no long cables that have to be charged. The kickers are now independently adjustable to eliminate any non-closure of the kicker system and therefore excitation of the stored beam. Setup, commissioning and fine tuning of this system are discussed

Ion source and injection line for high intensity medical cyclotron

Science.gov (United States)

Jia, XianLu; Guan, Fengping; Yao, Hongjuan; Zhang, TianJue; Yang, Jianjun; Song, Guofang; Ge, Tao; Qin, Jiuchang

2014-02-01

A 14 MeV high intensity compact cyclotron, CYCIAE-14, was built at China Institute of Atomic Energy (CIAE). An injection system based on the external H- ion source was used on CYCIAE-14 so as to provide high intensity beam, while most positron emission tomography cyclotrons adopt internal ion source. A beam intensity of 100 μA/14 MeV was extracted from the cyclotron with a small multi-cusp H- ion source (CIAE-CH-I type) and a short injection line, which the H- ion source of 3 mA/25 keV H- beam with emittance of 0.3π mm mrad and the injection line of with only 1.2 m from the extraction of ion source to the medial plane of the cyclotron. To increase the extracted beam intensity of the cyclotron, a new ion source (CIAE-CH-II type) of 9.1 mA was used, with maximum of 500 μA was achieved from the cyclotron. The design and test results of the ion source and injection line optimized for high intensity acceleration will be given in this paper.

TFTR neutral beam control and monitoring for DT operations

International Nuclear Information System (INIS)

O'Connor, T.; Kamperschroer, J.; Chu, J.

1995-01-01

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

Overview of the CERN Linac4 beam instrumentation

CERN Document Server

Roncarolo, F; Bravin, E; Dehning, B; Duraffourg, M; Gerard, D; Holzer, E B; Lenardon, F; Focker, G; Raich, U; Soby, L; Sordet, M; Tan, J; Tranquille, G; Vuitton, C; Zamantzas, C; Cheymol, B

2010-01-01

The CERN LINAC4 will represent the first upgrade of the LHC injection chain, by accelerating H- ions from 45 KeV to 160 MeV for charge-exchange injection into the PS Booster. In order to provide its safe and efficient commissioning and operation, a wide variety of beam diagnostics devices has been designed for installation at convenient locations all over the accelerator length and in the transfer line to the PS Booster. This paper gives an overview of all instrumentation devices, including those to measure beam position, transverse and longitudinal profile, beam current and beam loss. The well advanced status of the system design and the main instrument features are discussed

Achieving a long-lived high-beta plasma state by energetic beam injection

Science.gov (United States)

Guo, H. Y.; Binderbauer, M. W.; Tajima, T.; Milroy, R. D.; Steinhauer, L. C.; Yang, X.; Garate, E. G.; Gota, H.; Korepanov, S.; Necas, A.; Roche, T.; Smirnov, A.; Trask, E.

2015-04-01

Developing a stable plasma state with high-beta (ratio of plasma to magnetic pressures) is of critical importance for an economic magnetic fusion reactor. At the forefront of this endeavour is the field-reversed configuration. Here we demonstrate the kinetic stabilizing effect of fast ions on a disruptive magneto-hydrodynamic instability, known as a tilt mode, which poses a central obstacle to further field-reversed configuration development, by energetic beam injection. This technique, combined with the synergistic effect of active plasma boundary control, enables a fully stable ultra-high-beta (approaching 100%) plasma with a long lifetime.

Beam transport calculations for the EN tandem installation

International Nuclear Information System (INIS)

Sparks, R.J.

1980-12-01

Transport of a charged particle beam through the new EN tandem accelerator installation of the Institute of Nuclear Sciences has been analysed using simplified mathematical models. The purpose is to identify the factors affecting transmission of the beam, and to arrive at a design for the system to inject the beam into the accelerator

Electron energy distribution function in the divertor region of the COMPASS tokamak during neutral beam injection heating

Science.gov (United States)

Hasan, E.; Dimitrova, M.; Havlicek, J.; Mitošinková, K.; Stöckel, J.; Varju, J.; Popov, Tsv K.; Komm, M.; Dejarnac, R.; Hacek, P.; Panek, R.; the COMPASS Team

2018-02-01

This paper presents the results from swept probe measurements in the divertor region of the COMPASS tokamak in D-shaped, L-mode discharges, with toroidal magnetic field BT = 1.15 T, plasma current Ip = 180 kA and line-average electron densities varying from 2 to 8×1019 m-3. Using neutral beam injection heating, the electron energy distribution function is studied before and during the application of the beam. The current-voltage characteristics data are processed using the first-derivative probe technique. This technique allows one to evaluate the plasma potential and the real electron energy distribution function (respectively, the electron temperatures and densities). At the low average electron density of 2×1019 m-3, the electron energy distribution function is bi-Maxwellian with a low-energy electron population with temperatures 4-6 eV and a high-energy electron group 12-25 eV. As the line-average electron density is increased, the electron temperatures decrease. At line-average electron densities above 7×1019 m-3, the electron energy distribution function is found to be Maxwellian with a temperature of 6-8.5 eV. The effect of the neutral beam injection heating power in the divertor region is also studied.

Experiments on the margin of beam induced quenches a superconducting quadrupole magnet in the LHC

CERN Document Server

Bracco, C; Bednarek, M J; Nebot Del Busto, E; Goddard, B; Holzer, E B; Nordt, A; Sapinski, M; Schmidt, R; Solfaroli Camillocci, M; Zerlauth, M

2012-01-01

Protection of LHC equipment relies on a complex system of collimators to capture injected and circulating beam in case of LHC kicker magnet failures. However, for specific failures of the injection kickers, the beam can graze the injection protection collimators and induce quenches of downstream superconducting magnets. This occurred twice during 2011 operation and cannot be excluded during future operation. Tests were performed during Machine Development periods of the LHC to assess the quench margin of the quadrupole located just downstream of the last injection protection collimator in point 8. In addition to the existing Quench Protection System, a special monitoring instrumentation was installed at this magnet to detect any resistance increase below the quench limit. The correlation between the magnet and Beam Loss Monitor signals was analysed for different beam intensities and magnet currents. The results of the experiments are presented.

A Beam Quality Monitor for LHC Beams in the SPS

CERN Document Server

Papotti, G

2008-01-01

The SPS Beam Quality Monitor (BQM) system monitors the longitudinal parameters of the beam before extraction to the LHC to prevent losses and degradation of the LHC luminosity by the injection of low quality beams. It is implemented in two priority levels. At the highest level the SPS-LHC synchronization and global beam structure are verified. If the specifications are not met, the beam should be dumped in the SPS before extraction. On the second level, individual bunch position, length and stability are checked for beam quality assessment. Tolerances are adapted to the mode of operation and extraction to the LHC can also be inhibited. Beam parameters are accessed by acquiring bunch profiles with a longitudinal pick up and fast digital oscilloscope. The beam is monitored for instabilities during the acceleration cycle and thoroughly checked a few ms before extraction for a final decision on extraction interlock. Dedicated hardware and software components implementing fast algorithms are required. In this pape...

Photoelectric schlieren method used to study the properties of diesel engine injection systems

International Nuclear Information System (INIS)

Reznicek, R.

1987-01-01

The time dependence of the fuel flow rate issuing from the injector nozzle represents very important information concerning the properties of Diesel engine injection systems. By analysing the delivery rate, it is possible to judge a new design, and the modifications and adjustments of Diesel engine injection systems. A number of devices for measuring the delivery rate, frequently founded on mechanical principles, have also been constructed. Mechanical methods are laborious, require complicated measuring instruments, and the analysis of the results is quite tedious. For investigating the delivery rate, one can also use the intensity of the luminous flux of the light ray which is intersected, and consequently its intensity decreased, by the flow of the delivered fuel. The schlieren method can be used for this purpose, employing a thin beam of parallel light rays and a photoelectric sensor placed immediately beyond the cut-off slit. After adjustment and calibration, the variations of the original electric signal represent the time variation of the delivery rate by the nozzle

Premature beam dumps in 2011

CERN Document Server

Albert, Markus

2012-01-01

The statistical analysis of all non-programmed beam dumps during the 2011 proton run is presented. The selection criteria of fills that got considered were that the beam intensity of each of the two beams exceeded at least 1e12 particles per beam in order to exclude all probe beam dumps and most of the MPS test dumps. A distribution of beam dump causes by system is shown, as well as the time it took to re-establish injection after a non-programmed dump for fills which made it into STABLE BEAMS. This was done in an attempt to evaluate the cost of those non-programmed dumps in terms of time.

Beam dynamics issues in an extended relativistic klystron

International Nuclear Information System (INIS)

Giordano, G.; Li, H.; Goffeney, N.; Henestroza, E.; Sessler, A.; Yu, S.

1995-04-01

Preliminary studies of beam dynamics in a relativistic klystron were done to support a design study for a 1 TeV relativistic klystron two-beam accelerator (RK-TBA), 11.424 GHz microwave power source. This paper updates those studies. An induction accelerator beam is modulated, accelerated to 10 MeV, and injected into the RK with a rf current of about 1.2 kA. The main portion of the RK is the 300-m long extraction section comprise of 150 traveling-wave output structures and 900 induction accelerator cells. A periodic system of permanent quadrupole magnets is used for focusing. One and two dimensional numerical studies of beam modulation, injection into the main RK, transport and longitudinal equilibrium are presented. Transverse beam instability studies including Landau damping and the ''Betatron Node Scheme'' are presented

Methods of measuring of the ion beam transversal emittance in the injection channel of the cyclotron DC-72

CERN Document Server

Kazarinov, N; Kalagin, I V; Kazacha, V I

2002-01-01

The methods of measuring of the transversal emittance of ion beams in the cyclotron DC-72 injection channel with the help of the 'pepper-pot' and gradient means are discussed in this work. Two ways for the reconstruction of the ion beam transversal emittance are proposed for the 'pepper-pot' method. The first one can be used for beams having the uniform distribution of particles in the phase space. At that the values of the Twiss matrix and the full beam emittance are reconstructed according to the measurement results with the help of the phase ellipse fitting by the least-squares method. The corresponding FORTRAN code was created. On simulation the beam emittance was reconstructed with accuracy of 5%. The second method of the beam emittance reconstruction can be used in the common case at the arbitrary particle distribution in the phase space. It is based on calculation of the mean-square parameters of the beam according to the measurement results in the plane of the 'pepper-pot' mask. The mean-square emitta...

Plasma dynamics near an earth satellite and neutralization of its electric charge during electron beam injection into the ionosphere

International Nuclear Information System (INIS)

Fedorov, V.A.

2000-01-01

A study is made of the dynamics of the ionospheric plasma in the vicinity of an earth satellite injecting an electron beam. The time evolution of the electric charge of the satellite is determined. The electric potential of the satellite is found to be well below the beam-cutoff potential. It is shown that, under conditions typical of active experiments in space, the plasma electrons are capable of neutralizing the satellite's charge

Current drive by neutral beams, rotating magnetic fields and helicity injection in compact toroids

International Nuclear Information System (INIS)

Farengo, R.

2002-01-01

A Monte-Carlo code is used to study neutral beam current drive in Spheromaks. The exact particle trajectories are followed in the self-consistent equilibria calculated including the beam current. Reducing Z(eff) does not increase the current drive efficiency because the reduction of the stopping cross section is compensated by an increase in the electron canceling current. Significant changes in the safety factor profile can be produced with relatively low beam currents. Minimum dissipation states of a flux core spheromak sustained by helicity injection are presented. Helicity balance is used as a constraint and the resistivity is considered to be non-uniform. Two types of relaxed states are found; one has a central core of open flux surrounded by a toroidal region of closed flux surfaces and the other has the open flux wrapped around the closed flux surfaces. Non-uniform resistivity effects can be very important due to the changes they produce in the safety factor profile. A hybrid, fluid electrons particle ions, code is employed to study ion dynamics in FRCs sustained by rotating magnetic fields. (author)

Systems and methods of varying charged particle beam spot size

Science.gov (United States)

Chen, Yu-Jiuan

2014-09-02

Methods and devices enable shaping of a charged particle beam. A modified dielectric wall accelerator includes a high gradient lens section and a main section. The high gradient lens section can be dynamically adjusted to establish the desired electric fields to minimize undesirable transverse defocusing fields at the entrance to the dielectric wall accelerator. Once a baseline setting with desirable output beam characteristic is established, the output beam can be dynamically modified to vary the output beam characteristics. The output beam can be modified by slightly adjusting the electric fields established across different sections of the modified dielectric wall accelerator. Additional control over the shape of the output beam can be excreted by introducing intentional timing de-synchronization offsets and producing an injected beam that is not fully matched to the entrance of the modified dielectric accelerator.

DISSOLVED OXYGEN REDUCTION IN THE DIII-D NEUTRAL BEAM ION SOURCE COOLING SYSTEM

International Nuclear Information System (INIS)

YIP, H.; BUSATH, J.; HARRISON, S.

2004-03-01

OAK-B135 Neutral beam ion sources (NBIS) are critical components for the neutral beam injection system supporting the DIII-D tokamak. The NBIS must be cooled with 3028 (ell)/m (800 gpm) of de-ionized and de-oxygenated water to protect the sources from overheating and failure. These ions sources are currently irreplaceable. Since the water cooled molybdenum components will oxidize in water almost instantaneously in the presence of dissolved oxygen (DO), de-oxygenation is extremely important in the NBIS water system. Under normal beam operation the DO level is kept below 5 ppb. However, during weeknights and weekends when neutral beam is not in operation, the average DO level is maintained below 10 ppb by periodic circulation with a 74.6 kW (100 hp) pump, which consumes significant power. Experimental data indicated evidence of continuous oxygen diffusion through non-metallic hoses in the proximity of the NBIS. Because of the intermittent flow of the cooling water, the DO concentration at the ion source(s) could be even higher than measured downstream, and hence the concern of significant localized oxidation/corrosion. A new 3.73 kW (5 hp) auxiliary system, installed in the summer of 2003, is designed to significantly reduce the peak and the time-average DO levels in the water system and to consume only a fraction of the power

Design of the calorimeter and beam dump for the TFTR prototype neutral beam injector

International Nuclear Information System (INIS)

Stone, R.R.; Haughian, J.M.

1977-01-01

A calorimeter has been designed for use with the TFTR prototype neutral beam injection system. It consists of three vees each having two 18.8-mm-thick (0.75 in.) copper plates at a 6-deg angle, relative to the beam centerline. The maximum power density on a plate with this arrangement will be 2.0 kW/cm 2 , resulting in a front surface temperature rise of about 420 0 C. A support and retraction system moves the calorimeter in and out of the beam centerline. Various factors used in the selection of the absorber plate material will be discussed and also some experimental test results will be presented

Thermal analysis of the LHC injection kicker magnets

Science.gov (United States)

Vega, L.; Abánades, A.; Barnes, M. J.; Vlachodimitropoulos, V.; Weterings, W.

2017-07-01

The CERN Large Hadron Collider LHC is equipped with two fast pulsed magnet systems (MKIs) that inject particle beams coming from the injector chain. Operation with high intensity beams for many hours can lead to significant beam induced heating of the ferrite yokes of the MKIs. When the ferrite exceeds the Curie temperature of 125°C it loses its magnetic properties, preventing further injection until the ferrite cools down, potentially causing a delay of several hours. Hence important upgrades of the beam-screen were implemented after Run 1 of LHC. However, the High-Luminosity (HL) LHC will be operated with significantly higher intensity beams and hence additional measures are required to limit the ferrite temperature. These magnets operate under ultra-high vacuum conditions: convection is negligible and, as a result of low emissivity of the inside of the vacuum tanks, thermal radiation is limited. A detailed study of the thermal behaviour of these magnets is reported and compared with measurements. In addition several options to improve cooling of the ferrites are presented and analysed.

Computer control of the ISX-B neutral injection beamlines

International Nuclear Information System (INIS)

Hanna, P.C.

1982-09-01

A system of controls for the Impurity Study Experiment (ISX-B) neutral injection beamlines at the Oak Ridge National Laboratory is presented. The system uses standard CAMAC equipment interfaced to the actual beamline controls and driven by a PDP-11/34 mini-computer. It is designed to relieve the operator of most of the mundane tasks of beam injection and also to reduce the number of operators needed to monitor multiple beamlines

Improvement of Galilean refractive beam shaping system for accurately generating near-diffraction-limited flattop beam with arbitrary beam size.

Science.gov (United States)

Ma, Haotong; Liu, Zejin; Jiang, Pengzhi; Xu, Xiaojun; Du, Shaojun

2011-07-04

We propose and demonstrate the improvement of conventional Galilean refractive beam shaping system for accurately generating near-diffraction-limited flattop beam with arbitrary beam size. Based on the detailed study of the refractive beam shaping system, we found that the conventional Galilean beam shaper can only work well for the magnifying beam shaping. Taking the transformation of input beam with Gaussian irradiance distribution into target beam with high order Fermi-Dirac flattop profile as an example, the shaper can only work well at the condition that the size of input and target beam meets R(0) ≥ 1.3 w(0). For the improvement, the shaper is regarded as the combination of magnifying and demagnifying beam shaping system. The surface and phase distributions of the improved Galilean beam shaping system are derived based on Geometric and Fourier Optics. By using the improved Galilean beam shaper, the accurate transformation of input beam with Gaussian irradiance distribution into target beam with flattop irradiance distribution is realized. The irradiance distribution of the output beam is coincident with that of the target beam and the corresponding phase distribution is maintained. The propagation performance of the output beam is greatly improved. Studies of the influences of beam size and beam order on the improved Galilean beam shaping system show that restriction of beam size has been greatly reduced. This improvement can also be used to redistribute the input beam with complicated irradiance distribution into output beam with complicated irradiance distribution.

The development of new injection septum magnet for upgrating of J-PARC MR (3)

International Nuclear Information System (INIS)

Shibata, Tatsunobu; Ishii, Koji; Sugimoto, Takuya; Matsumoto, Noriyuki; Matsumoto, Hiroshi; Fan, Kuanjun; Kawaguchi, Yusuke; Nakamura, Kenta; Hamano, Kei

2017-01-01

We are improving the Main Ring (MR) for beam power of 750 kW which is a first goal of J-PARC. The repetition period of the Fast eXtraction(FX) must be shorten to 1.3 sec from the current period of 2.48 sec for the improvement of the beam power. We must upgrade injection and extraction magnets and their power supplies for upgrading the beam power. In 2016 summer, we have finished the replacement of a high field injection septum magnet and its power supply. One of the main reason was that the previous injection septum system could not be operated with 1.3 sec repetition. The other thing was that we have confirmed the large leakage field around circulating beam line of the injection magnet, so we must reduce them. The new injection septum magnet and its power supply were produced in 2014. We started to conduct the test-operation of the power supply and measurement of the magnetic field in 2015, and finished in August 2016, We have started the beam operation with the new injection septum in October 2016. The converter units in the new power supply of the new injection septum were broken in October and November 2016 as initial trouble. The main source of the trouble was electric noise in the gate signal. After countermeasure, we have no trouble in the power supply. We have found that there is still small leakage field in the upstream line of the new injection septum. We have installed an additional magnetic shield to the new injection septum. (author)

A verification scenario of nuclear plus interference scattering effects using neutron incident angle distribution to the wall in beam-injected deuterium plasmas

International Nuclear Information System (INIS)

Sugiyama, Shota; Matsuura, Hideaki; Uchiyama, Daisuke; Sawada, Daisuke; Watanabe, Tsuguhiro; Goto, Takuya; Mitarai, Osamu

2015-01-01

A verification scenario of knock-on tail formation in the deuteron distribution function due to nuclear plus interference scattering is presented by observing the incident angle distribution of neutrons in a vacuum vessel. Assuming a knock-on tail created in a "3He-beam-injected deuterium plasma, the incident angle distribution and energy spectra of the neutrons produced by fusion reactions between 1-MeV and thermal deuterons are evaluated. The relation between the neutron incident angle to the vacuum vessel and neutron energy is examined in the case of anisotropic neutron emission due to knock-on tail formation in neutral-beam-injected plasmas. (author)

Helium refrigeration system for BNL colliding beam accelerator

International Nuclear Information System (INIS)

Brown, D.P.; Farah, Y.; Gibbs, R.J.; Schlafke, A.P.; Schneider, W.J.; Sondericker, J.H.; Wu, K.C.

1983-01-01

A Helium Refrigeration System which will supply the cooling required for the Colliding Beam Accelerator at Brookhaven National Laboratory is under construction. Testing of the compressor system is scheduled for late 1983 and will be followed by refrigerator acceptance tests in 1984. The refrigerator has a design capacity of 24.8 kW at a temperature level near 4K while simultaneously producing 55 kW for heat shield loads at 55K. When completed, the helium refrigerator will be the world's largest. Twenty-five oil-injected screw compressors with an installed total of 23,250 horsepower will supply the gas required. One of the unique features of the cycle is the application of three centrifugal compressors used at liquid helium temperature to produce the low temperatures (2.5K) and high flow rates (4154 g/s) required for this service

Numerical simulation of injection and resistive trapping of ion rings

International Nuclear Information System (INIS)

Mankofsky, A.; Friedman, A.; Sudan, R.N.

1981-01-01

Numerical studies of the injection and resistive trapping efficiency of ion rings, using an improved algorithm are presented. Trapping efficiency is found to be strongly dependent upon the number of particles injected and upon mirror ratios in the system. Wall resistivity and beam divergence affect the process to a lesser extent. (author)

Density peaking in the JFT-2M tokamak plasma with counter neutral beam injection

International Nuclear Information System (INIS)

Ida, K.; Itoh, S.; Itoh, K.

1991-05-01

A significant particle pinch and reduction of the effective thermal diffusivity are observed after switching the neutral beam direction from co- to counter- injection in the JFT-2M tokamak. A time delay in the occurrence of density peaking to that of plasma rotation is found. This shows that the particle pinch is related to the profile of the electric field as determined by the plasma rotation profile. The measured particle flux shows qualitative agreement with the theoretically-predicted inward pinch. (author)

Injection of 1 GeV H- beam into the JHF I-A ring

International Nuclear Information System (INIS)

Yamane, Isao; Kitagawa, Kiyoshi; Someya, Hirohiko; Yano, Yoshiharu.

1988-11-01

Application of the H 0 injection method to the injection system of the JHF I-A ring was studied. It turned out that the H 0 injection method is adequate when some conditions are fulfilled. The ways to fulfill those conditions are described. (author)

Optimization of laser-plasma injector via beam loading effects using ionization-induced injection

Science.gov (United States)

Lee, P.; Maynard, G.; Audet, T. L.; Cros, B.; Lehe, R.; Vay, J.-L.

2018-05-01

Simulations of ionization-induced injection in a laser driven plasma wakefield show that high-quality electron injectors in the 50-200 MeV range can be achieved in a gas cell with a tailored density profile. Using the PIC code Warp with parameters close to existing experimental conditions, we show that the concentration of N2 in a hydrogen plasma with a tailored density profile is an efficient parameter to tune electron beam properties through the control of the interplay between beam loading effects and varying accelerating field in the density profile. For a given laser plasma configuration, with moderate normalized laser amplitude, a0=1.6 and maximum electron plasma density, ne 0=4 ×1018 cm-3 , the optimum concentration results in a robust configuration to generate electrons at 150 MeV with a rms energy spread of 4% and a spectral charge density of 1.8 pC /MeV .

Dumping the decelerated beams of CLIC

CERN Document Server

Jeanneret, Bernard

2011-01-01

The spent drive beam must be cleanly extracted and bent away from the decelerator axis at the end of each CLIC decelerator in order to leave space for injecting a fresh beam train in the next sector. Then the spent beam must be safely absorbed. A compact extraction system made of a single dipole is proposed. The spent beam is driven to a water dump located at 20m downstream of the extraction point and transversely 6m away of the axis of the main linac. An adequate spread of the beam impact map on the dump offers small temperature excursions in both the dump and its entrance window, allowing for reliable operation and a long lifetime of the system.

High quality proton beams from hybrid integrated laser-driven ion acceleration systems

Energy Technology Data Exchange (ETDEWEB)

Sinigardi, Stefano, E-mail: sinigardi@bo.infn.it [Dipartimento di Fisica e Astronomia, Università di Bologna and INFN Sezione di Bologna, Via Irnerio 46, I-40126 Bologna (Italy); Turchetti, Giorgio; Rossi, Francesco; Londrillo, Pasquale [Dipartimento di Fisica e Astronomia, Università di Bologna and INFN Sezione di Bologna, Via Irnerio 46, I-40126 Bologna (Italy); Giove, Dario; De Martinis, Carlo [Dipartimento di Fisica, Università di Milano and INFN Sezione di Milano, Via F.lli Cervi 201, I-20090 Segrate (Italy); Bolton, Paul R. [Kansai Photon Science Institute (JAEA), Umemidai 8-1-7, Kizugawa-shi, Kyoto 619-0215 (Japan)

2014-03-11

We consider a hybrid acceleration scheme for protons where the laser generated beam is selected in energy and angle and injected into a compact linac, which raises the energy from 30 to 60 MeV. The laser acceleration regime is TNSA and the energy spectrum is determined by the cutoff energy and proton temperature. The dependence of the spectrum on the target properties and the incidence angle is investigated with 2D PIC simulations. We base our work on widely available technologies and on laser with a short pulse, having in mind a facility whose cost is approximately 15M€. Using a recent experiment as the reference, we choose the laser pulse and target so that the energy spectrum obtained from the 3D PIC simulation is close to the one observed, whose cutoff energy was estimated to be over 50 MeV. Laser accelerated protons in the TNSA regime have wide energy spectrum and broad divergence. In this paper we compare three transport lines, designed to perform energy selection and beam collimation. They are based on a solenoid, a quadruplet of permanent magnetic quadrupoles and a chicane. To increase the maximum available energy, which is actually seen as an upper limit due to laser properties and available targets, we propose to inject protons into a small linac for post-acceleration. The number of selected and injected protons is the highest with the solenoid and lower by one and two orders of magnitude with the quadrupoles and the chicane respectively. Even though only the solenoid enables achieving to reach a final intensity at the threshold required for therapy with the highest beam quality, the other systems will be very likely used in the first experiments. Realistic start-to-end simulations, as the ones reported here, are relevant for the design of such experiments.

High quality proton beams from hybrid integrated laser-driven ion acceleration systems

Science.gov (United States)

Sinigardi, Stefano; Turchetti, Giorgio; Rossi, Francesco; Londrillo, Pasquale; Giove, Dario; De Martinis, Carlo; Bolton, Paul R.

2014-03-01

We consider a hybrid acceleration scheme for protons where the laser generated beam is selected in energy and angle and injected into a compact linac, which raises the energy from 30 to 60 MeV. The laser acceleration regime is TNSA and the energy spectrum is determined by the cutoff energy and proton temperature. The dependence of the spectrum on the target properties and the incidence angle is investigated with 2D PIC simulations. We base our work on widely available technologies and on laser with a short pulse, having in mind a facility whose cost is approximately 15 M €. Using a recent experiment as the reference, we choose the laser pulse and target so that the energy spectrum obtained from the 3D PIC simulation is close to the one observed, whose cutoff energy was estimated to be over 50 MeV. Laser accelerated protons in the TNSA regime have wide energy spectrum and broad divergence. In this paper we compare three transport lines, designed to perform energy selection and beam collimation. They are based on a solenoid, a quadruplet of permanent magnetic quadrupoles and a chicane. To increase the maximum available energy, which is actually seen as an upper limit due to laser properties and available targets, we propose to inject protons into a small linac for post-acceleration. The number of selected and injected protons is the highest with the solenoid and lower by one and two orders of magnitude with the quadrupoles and the chicane respectively. Even though only the solenoid enables achieving to reach a final intensity at the threshold required for therapy with the highest beam quality, the other systems will be very likely used in the first experiments. Realistic start-to-end simulations, as the ones reported here, are relevant for the design of such experiments.

High quality proton beams from hybrid integrated laser-driven ion acceleration systems

International Nuclear Information System (INIS)

Sinigardi, Stefano; Turchetti, Giorgio; Rossi, Francesco; Londrillo, Pasquale; Giove, Dario; De Martinis, Carlo; Bolton, Paul R.

2014-01-01

We consider a hybrid acceleration scheme for protons where the laser generated beam is selected in energy and angle and injected into a compact linac, which raises the energy from 30 to 60 MeV. The laser acceleration regime is TNSA and the energy spectrum is determined by the cutoff energy and proton temperature. The dependence of the spectrum on the target properties and the incidence angle is investigated with 2D PIC simulations. We base our work on widely available technologies and on laser with a short pulse, having in mind a facility whose cost is approximately 15M€. Using a recent experiment as the reference, we choose the laser pulse and target so that the energy spectrum obtained from the 3D PIC simulation is close to the one observed, whose cutoff energy was estimated to be over 50 MeV. Laser accelerated protons in the TNSA regime have wide energy spectrum and broad divergence. In this paper we compare three transport lines, designed to perform energy selection and beam collimation. They are based on a solenoid, a quadruplet of permanent magnetic quadrupoles and a chicane. To increase the maximum available energy, which is actually seen as an upper limit due to laser properties and available targets, we propose to inject protons into a small linac for post-acceleration. The number of selected and injected protons is the highest with the solenoid and lower by one and two orders of magnitude with the quadrupoles and the chicane respectively. Even though only the solenoid enables achieving to reach a final intensity at the threshold required for therapy with the highest beam quality, the other systems will be very likely used in the first experiments. Realistic start-to-end simulations, as the ones reported here, are relevant for the design of such experiments

Charge exchange measurements of MHD activity during neutral beam injection in the Princeton Large Torus and the Poloidal Divertor Experiment

International Nuclear Information System (INIS)

Goldston, R.J.; Kaita, R.; Beiersdorfer, P.; Gammel, G.; Herndon, D.L.; McCune, D.C.; Meyerhofer, D.D.

1987-01-01

The horizontally scanning, multi-angle charge exchange analysers on the Princeton Large Torus (PLT) and the Poloidal Divertor Experiment (PDX) were used to study the effects of MHD activity on the background ion distribution function and on the beam ion slowing-down process during high power neutral injection. Sawtooth oscillations were observed in the fast ion flux on PLT and PDX, and measurements with neutral beams providing local neutral density enhancement indicated that the ions were transported radially when these events occurred. With near-perpendicular injection in PDX, at the lower toroidal fields necessary to maximize the plasma beta, repetitive bursts of greatly enhanced charge exchange flux were observed. These were associated with the 'fishbone' MHD instability, and a substantial depletion of the perpendicular slowing-down spectrum below the injection energy was seen. A simple phenomenological model for this loss mechanism was developed, and its use in simulation codes has been successful in providing good agreement with the experimental data. The behaviour and characteristics of this model are well matched by direct theoretical calculations. (author)

Charge-exchange measurements of MHD activity during neutral beam injection in the Princeton Large Torus and the Poloidal Divertor Experiment

International Nuclear Information System (INIS)

Goldston, R.J.; Kaita, R.; Beiersdorfer, P.; Gammel, G.; Herndon, D.L.; McCune, D.C.; Meyerhofer, D.D.

1986-07-01

The horizontally scanning, multiangle charge-exchange analyzers on the Princeton Large Torus (PLT) and the Poloidal Divertor Experiment (PDX) were used to study the effects of MHD activity on the background ion distribution function and on the beam ion slowing-down process during high-power neutral injection. Sawtooth oscillations were observed in the fast ion flux on PLT and PDX, and measurements with neutral beams providing local neutral density enhancement indicate that ions are transported radially when these events occur. With near-perpendicular injection in PDX, at the lower toroidal fields necessary to maximize beta, rapid, repetitive bursts of greatly enhanced charge-exchange flux were observed. These are associated with the ''fishbone'' MHD instability, and a substantial depletion of the perpendicular slowing-down spectrum below the injection energy was seen. A simple phenomenological model for this loss mechanism was developed, and its use in simulation codes has been successful in providing good agreement with the data. The behavior and characteristics of this model are well matched by the direct theoretical calculations

Implementation of a Direct Link between the LHC Beam Interlock System and the LHC Beam Dumping System Re-Triggering Lines

CERN Document Server

Gabourin, S; Denz, R; Magnin, N; Uythoven, J; Wollmann, D; Zerlauth, M; Vatansever, V; Bartholdt, M; Bertsche, B; Zeiler, P

2014-01-01

To avoid damage of accelerator equipment due to impacting beam, the controlled removal of the LHC beams from the collider rings towards the dump blocks must be guaranteed at all times. When a beam dump is demanded, the Beam Interlock System communicates this request to the Trigger Synchronisation and Distribution System of the LHC Beam Dumping System. Both systems were built according to high reliability standards. To further reduce the risk of incapability to dump the beams in case of correlated failures in the Trigger Synchronisation and Distribution System, a new direct link from the Beam Interlock System to the re-triggering lines of the LHC Beam Dumping System will be implemented for the start-up with beam in 2015. The link represents a diverse redundancy to the current implementation, which should neither significantly increase the risk for so-called asynchronous beam dumps nor compromise machine availability. This paper describes the implementation choices of this link. Furthermore the results of a rel...

Electron beam interaction with space plasmas

International Nuclear Information System (INIS)

Krafft, C.; Volokitin, A.S.

1999-01-01

Active space experiments involving the controlled injection of electron beams and the formation of artificially generated currents can provide in many cases a calibration of natural phenomena connected with the dynamic interaction of charged particles with fields. They have a long history beginning from the launches of small rockets with electron guns in order to map magnetic fields lines in the Earth's magnetosphere or to excite artificial auroras. Moreover, natural beams of charged particles exist in many space and astrophysical plasmas and were identified in situ by several satellites; a few examples are beams connected with solar bursts, planetary foreshocks or suprathermal fluxes traveling in planetary magnetospheres. Many experimental and theoretical works have been performed in order to interpret or plan space experiments involving beam injection as well as to understand the physics of wave-particle interaction, as wave radiation, beam dynamics and background plasma modification. Recently, theoretical studies of the nonlinear evolution of a thin monoenergetic electron beam injected in a magnetized plasma and interacting with a whistler wave packet have led to new results. The influence of an effective dissipation process connected with whistler wave field leakage out of the beam volume to infinity (that is, effective radiation outside the beam) on the nonlinear evolution of beam electrons distribution in phase space has been studied under conditions relevant to active space experiments and related laboratory modelling. The beam-waves system's evolution reveals the formation of stable nonlinear structures continuously decelerated due to the effective friction imposed by the strongly dissipated waves. The nonlinear interaction between the electron bunches and the wave packet are discussed in terms of dynamic energy exchange, particle trapping, slowing down of the beam, wave dissipation and quasi-linear diffusion. (author)

Neutral particle beam alternative concept for ITER

International Nuclear Information System (INIS)

Sedgley, D.; Brook, J.; Luzzi, T.; Deutsch, L.

1989-01-01

An analysis of an ITER neutral particle beam system is presented. The analysis covers the neutralizer, ion dumps, pumping, and geometric aspects. The US beam concept for ITER consists of three or four clusters of beamlines delivering approximately 80 MW total of 1.6-MeV deuterium to three or four reactor ports. Each cluster has three self-contained beamlines featuring plasma neutralizers and electrostatic ion dumps. In this study, each of the beamlines has two source assemblies with separate gas neutralizers and magnetic ion dumps. Deuterium is injected into the gas neutralizers by a separate system. Saddle-shaped copper coils augment the tokamak poloidal field to turn the charged particles into the ion dumps. The gas flow from the source, neutralizer, and ion dump is pumped by regenerable cryopanels. The effect of the port between the TF coils and the beam injection angle on the plasma footprint was studied

Prompt Loss of Energetic Ions during Early Neutral Beam Injection in the National Spherical Torus Experiment

International Nuclear Information System (INIS)

Medley, S.S.; Darrow, D.S.; Liu, D.; Roquemore, A.L.

2005-01-01

Early neutral-beam injection is used in the National Spherical Torus Experiment (NSTX) to heat the electrons and slow current penetration which keeps q(0) elevated to avoid deleterious MHD activity and at the same time reduces Ohmic flux consumption, all of which aids long-pulse operation. However, the low plasma current (I p ∼ 0.5 MA) and electron density (n e ∼ 1 x 10 13 cm -3 ) attending early injection lead to elevated orbit and shine through losses. The inherent orbit losses are aggravated by large excursions in the outer gap width during current ramp-up. An investigation of this behavior using various energetic particle diagnostics on NSTX and TRANSP code analysis is presented

Automated Calculation of DIII-D Neutral Beam Availability

International Nuclear Information System (INIS)

Phillips, J.C.; Hong, R.M.; Scoville, B.G.

1999-01-01

The neutral beam systems for the DIII-D tokamak are an extremely reliable source of auxiliary plasma heating, capable of supplying up to 20 MW of injected power, from eight separate beam sources into each tokamak discharge. The high availability of these systems for tokamak operations is sustained by careful monitoring of performance and following up on failures. One of the metrics for this performance is the requested injected power profile as compared to the power profile delivered for a particular pulse. Calculating this was a relatively straightforward task, however innovations such as the ability to modulate the beams and more recently the ability to substitute an idle beam for one which has failed during a plasma discharge, have made the task very complex. For example, with this latest advance it is possible for one or more beams to have failed, yet the delivered power profile may appear perfect. Availability used to be manually calculated. This paper presents the methods and algorithms used to produce a system which performs the calculations based on information concerning the neutral beam and plasma current waveforms, along with post-discharge information from the Plasma Control System, which has the ability to issue commands for beams in real time. Plots representing both the requested and actual power profiles, along with statistics, are automatically displayed and updated each shot, on a web-based interface viewable both at DIII-D and by our remote collaborators using no-cost software

H- charge exchange injection systems

International Nuclear Information System (INIS)

Ankenbrandt, C.; Curtis, C.; Hojvat, C.; Johnson, R.P.; Owen, C.; Schmidt, C.; Teng, L.; Webber, R.C.

1980-01-01

The techniques and components required for injection of protons into cyclic accelerators by means of H - charge exchange processes are reviewed, with emphasis on the experience at Fermilab. The advantages of the technique are described. The design and performance of the system of injection of H - ions into the Fermilab Booster are detailed. (Auth.)

Design of the injection channel magnets for the K1200 cyclotron

International Nuclear Information System (INIS)

Wu, X.Y.; Lawton, D.; Marti, F.; Zeller, A.F.

2001-01-01

The beam from the K500 cyclotron is injected radially into the median plane of the K1200 cyclotron where it is stripped inside a dee. Along the injection path, the injected beam traverses large magnetic gradients under the K1200 superconducting coil and on the edge of the hill. To match the injected beam to the eigen-ellipse for the accelerated beam, two magnetic elements are included in the injection channel in the yoke of the K1200 cyclotron. One of them is an active element and the other a conical focusing passive element. This last element must move in the horizontal plane to match the different beam paths. We describe in the paper the beam dynamics calculations as well as the mechanical design and construction of these magnets

Neutron measurements from beam-target reactions at the ELISE neutral beam test facility

International Nuclear Information System (INIS)

Xufei, X.; Fan, T.; Nocente, M.; Gorini, G.; Bonomo, F.; Franzen, P.; Fröschle, M.; Grosso, G.; Tardocchi, M.; Grünauer, F.; Pasqualotto, R.

2014-01-01

Measurements of 2.5 MeV neutron emission from beam-target reactions performed at the ELISE neutral beam test facility are presented in this paper. The measurements are used to study the penetration of a deuterium beam in a copper dump, based on the observation of the time evolution of the neutron counting rate from beam-target reactions with a liquid scintillation detector. A calculation based on a local mixing model of deuterium deposition in the target up to a concentration of 20% at saturation is used to evaluate the expected neutron yield for comparison with data. The results are of relevance to understand neutron emission associated to beam penetration in a solid target, with applications to diagnostic systems for the SPIDER and MITICA Neutral Beam Injection prototypes

Engineering of beam direct conversion for a 120-kV, 1-MW ion beam

International Nuclear Information System (INIS)

Barr, W.L.; Doggett, J.N.; Hamilton, G.W.; Kinney, J.D.; Moir, R.W.

1977-01-01

Practical systems for beam direct conversion are required to recover the energy from ion beams at high efficiency and at very high beam power densities in the environment of a high-power, neutral-injection system. Such an experiment is now in progress using a 120-kV beam with a maximum total current of 20 A. After neutralization, the H + component to be recovered will have a power of approximately 1MW. A system testing these concepts has been designed and tested at 15 kV, 2 kW in preparation for the full-power tests. The engineering problems involved in the full-power tests affect electron suppression, gas pumping, voltage holding, diagnostics, and measurement conditions. Planning for future experiments at higher power includes the use of cryopumping and electron suppression by a magnetic field rather than by an electrostatic field. Beam direct conversion for large fusion experiments and reactors will save millions of dollars in the cost of power supplies and electricity and will dispose of the charged beam under conditions that may mot be possible by other techniques

Engineering of beam direct conversion for a 120-kV, 1-MW ion beam

International Nuclear Information System (INIS)

Barr, W.L.; Doggett, J.N.; Hamilton, G.W.; Kinney, J.D.; Moir, R.W.

1977-01-01

Practical systems for beam direct conversion are required to recover the energy from ion beams at high efficiency and at very high beam power densities in the environment of a high-power, neutral-injection system. Such an experiment is now in progress using a 120-kV beam with a maximum total current of 20 A. After neutralization, the H + component to be recovered will have a power of approximately 1 MW. A system testing these concepts has been designed and tested at 15 kV, 2 kW in preparation for the full-power tests. The engineering problems involved in the full-power tests affect electron suppression, gas pumping, voltage holding, diagnostics, and measurement conditions. Planning for future experiments at higher power includes the use of cryopumping and electron suppression by a magnetic field rather than by an electrostatic field. Beam direct conversion for large fusion experiments and reactors will save millions of dollars in the cost of power supplies and electricity and will dispose of the charged beam under conditions that may not be possible by other techniques

Neutral beam development plan

International Nuclear Information System (INIS)

Staten, H.S.

1980-08-01

The national plan is presented for developing advanced injection systems for use on upgrades of existing experiments, and use on future facilities such as ETF, to be built in the late 1980's or early 90's where power production from magnetic fusion will move closer to a reality. Not only must higher power and longer pulse length systems be developed , but they must operate reliably; they must be a tool for the experimenter, not the experiment itself. Neutral beam systems handle large amounts of energy and as such, they often are as complicated as the plasma physics experiment itself. This presents a significant challenge to the neutral beam developer

Preliminary analysis of beam trip and beam jump events in an ADS prototype

International Nuclear Information System (INIS)

D'Angelo, A.; Bianchini, G.; Carta, M.

2001-01-01

A core dynamics analysis relevant to some typical current transient events has been carried out on an 80 MW energy amplifier prototype (EAP) fuelled by mixed oxides and cooled by lead-bismuth. Fuel and coolant temperature trends relevant to recovered beam trip and beam jump events have been preliminary investigated. Beam trip results show that the drop in temperature of the core outlet coolant would be reduced a fair amount if the beam intensity could be recovered within few seconds. Due to the low power density in the EAP fuel, the beam jump from 50% of the nominal power transient evolves benignly. The worst thinkable current transient, beam jump with cold reactor, mainly depends on the coolant flow conditions. In the EAP design, the primary loop coolant flow is assured by natural convection and is enhanced by a particular system of cover gas injection into the bottom part of the riser. If this system of coolant flow enhancement is assumed in function, even the beam jump with cold reactor event evolves without severe consequences. (authors)

Initial results from beam commissioning of the LHC beam dump system

CERN Document Server

Goddard, B; Carlier, E; Ducimetière, L; Gallet, E; Gyr, M; Jensen, L; Jones, R; Kain, V; Kramer, T; Lamont, M; Meddahi, M; Mertens, V; Risselada, Thys; Uythoven, J; Wenninger, J; Weterings, W

2010-01-01

Initial commissioning of the LHC beam dump system with beam took place in August and September 2008. The preparation, setting-up and the tests performed are described together with results of the extractions of beam into the dump lines. Analysis of the first detailed aperture measurements of the extraction channels and kicker performance derived from dilution sweep shapes are presented. The performance of the other equipment subsystems is summarised, in particular that of the dedicated dump system beam instrumentation.

Contrastive Analysis and Research on Negative Pressure Beam Tube System and Positive Pressure Beam Tube System for Mine Use

Science.gov (United States)

Wang, Xinyi; Shen, Jialong; Liu, Xinbo

2018-01-01

Against the technical defects of universally applicable beam tube monitoring system at present, such as air suction in the beam tube, line clogging, long sampling time, etc., the paper analyzes the current situation of the spontaneous combustion fire disaster forecast of mine in our country and these defects one by one. On this basis, the paper proposes a research thought that improving the positive pressure beam tube so as to substitute the negative pressure beam tube. Then, the paper introduces the beam tube monitoring system based on positive pressure technology through theoretical analysis and experiment. In the comparison with negative pressure beam tube, the paper concludes the advantage of the new system and draws the conclusion that the positive pressure beam tube is superior to the negative pressure beam tube system both in test result and test time. At last, the paper proposes prospect of the beam tube monitoring system based on positive pressure technology.