WorldWideScience

Sample records for energy electron accelerators

  1. Compact multi-energy electron linear accelerators

    International Nuclear Information System (INIS)

    Tanabe, E.; Hamm, R.W.

    1985-01-01

    Two distinctly different concepts that have been developed for compact multi-energy, single-section, standing-wave electron linear accelerator structures are presented. These new concepts, which utilize (a) variable nearest neighbor couplings and (b) accelerating field phase switching, provide the capability of continuously varying the electron output energy from the accelerator without degrading the energy spectrum. These techniques also provide the means for continuously varying the energy spectrum while maintaining a given average electron energy, and have been tested successfully with several accelerators of length from 0.1 m to 1.9 m. Theoretical amd experimental results from these accelerators, and demonstrated applications of these techniques to medical and industrial linear accelerator technology will be described. In addition, possible new applications available to research and industry from these techniques are presented. (orig.)

  2. Can Low Energy Electrons Affect High Energy Physics Accelerators?

    International Nuclear Information System (INIS)

    Cimino, Roberto

    2004-01-01

    The properties of the electrons participating in the build up of an electron cloud (EC) inside the beam-pipe have become an increasingly important issue for present and future accelerators whose performance may be limited by this effect. The EC formation and evolution are determined by the wall-surface properties of the accelerator vacuum chamber. Thus, the accurate modeling of these surface properties is an indispensible input to simulation codes aimed at the correct prediction of build-up thresholds, electron-induced instability or EC heat load. In this letter, we present the results of surface measurements performed on a prototype of the beam screen adopted for the Large Hadron Collider (LHC), which presently is under construction at CERN. We have measured the total secondary electron yield (SEY) as well as the related energy distribution curves (EDC) of the secondary electrons as a function of incident electron energy. Attention has been paid, for the first time in this context, to the probability at which low-energy electrons (<∼ 20 eV) impacting on the wall create secondaries or are elastically reflected. It is shown that the ratio of reflected to true-secondary electrons increases for decreasing energy and that the SEY approaches unity in the limit of zero primary electron energy

  3. An energy monitor for electron accelerators

    International Nuclear Information System (INIS)

    Geske, G.

    1990-01-01

    A monitor useful for checks of the energy selector scale of medical electron accelerators was developed and tested. It consists of a linear array of flat ionization chambers sandwiched between absorber plates of low-Z material. The first chamber at the electron beam entrance may be used to produce a reference signal S r , if not another suitable reference signal is taken. The following chambers are electrically connected and deliver the measuring signal S m . A clinical dosimeter can be used for recording current or charge. The energy-dependent electron range parameters R p , R 50 and R 80 in water vary as linear functions of the ratio reference singal/measuring signal. The best linear fit was obtained for the half value layer R 50 . Three types of the energy monitor are described, and experimental results obtained with a linear accelerator and a betatron between 5 and 25 MeV are reported. Uncertainties for checks of R 50 with a calibrated energy monitor were not larger than 1 to 2 mm. Theoretical considerations by a computer model support these results. (orig./HP) [de

  4. Can low energy electrons affect high energy physics accelerators?

    CERN Document Server

    Cimino, R; Furman, M A; Pivi, M; Ruggiero, F; Rumolo, Giovanni; Zimmermann, Frank

    2004-01-01

    The properties of the electrons participating in the build up of an electron cloud (EC) inside the beam-pipe have become an increasingly important issue for present and future accelerators whose performance may be limited by this effect. The EC formation and evolution are determined by the wall-surface properties of the accelerator vacuum chamber. Thus, the accurate modeling of these surface properties is an indispensible input to simulation codes aimed at the correct prediction of build-up thresholds, electron-induced instability or EC heat load. In this letter, we present the results of surface measurements performed on a prototype of the beam screen adopted for the Large Hadron Collider (LHC), which presently is under construction at CERN. We have measured the total secondary electron yield (SEY) as well as the related energy distribution curves (EDC) of the secondary electrons as a function of incident electron energy. Attention has been paid, for the first time in this context, to the probability at whic...

  5. Electron beam accelerator energy control system

    International Nuclear Information System (INIS)

    Sharma, Vijay; Rajan, Rehim; Acharya, S.; Mittal, K.C.

    2011-01-01

    A control system has been developed for the energy control of the electron beam accelerator using PLC. The accelerating voltage of 3 MV has been obtained by using parallel coupled voltage multiplier circuit. A autotransformer controlled variable 0-10 KV DC is fed to a tube based push pull oscillator to generate 120 Khz, 10 KV AC. Oscillator output voltage is stepped up to 0-300 KV/AC using a transformer. 0-300 KVAC is fed to the voltage multiplier column to generate the accelerating voltage at the dome 0-3 MV/DC. The control system has been designed to maintain the accelerator voltage same throughout the operation by adjusting the input voltage in close loop. Whenever there is any change in the output voltage either because of beam loading or arcing in the accelerator. The instantaneous accelerator voltage or energy is a direct proportional to 0-10 KVDC obtained from autotransformer. A PLC based control system with user settable energy level has been installed for 3 MeV, EB accelerator. The PLC takes the user defined energy value through a touch screen and compares it to the actual accelerating voltage (obtained using resistive divider). Depending upon the error the PLC generates the pulses to adjust the autotransformer to bring the actual voltage to the set value within the window of error (presently set to +/- 0.1%). (author)

  6. An energy monitor for electron accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Geske, G. (Friedrich-Schiller-Universitaet, Jena (German Democratic Republic). Klinik und Poliklinik des Bereiches Medizin)

    1990-09-01

    A monitor useful for checks of the energy selector scale of medical electron accelerators was developed and tested. It consists of a linear array of flat ionization chambers sandwiched between absorber plates of low-Z material. The first chamber at the electron beam entrance may be used to produce a reference signal S{sub r}, if not another suitable reference signal is taken. The following chambers are electrically connected and deliver the measuring signal S{sub m}. A clinical dosimeter can be used for recording current or charge. The energy-dependent electron range parameters R{sub p}, R{sub 50} and R{sub 80} in water vary as linear functions of the ratio reference singal/measuring signal. The best linear fit was obtained for the half value layer R{sub 50}. Three types of the energy monitor are described, and experimental results obtained with a linear accelerator and a betatron between 5 and 25 MeV are reported. Uncertainties for checks of R{sub 50} with a calibrated energy monitor were not larger than 1 to 2 mm. Theoretical considerations by a computer model support these results. (orig./HP).

  7. Utilization of low-energy electron accelerators in Korea

    International Nuclear Information System (INIS)

    Lee, Byung Cheol

    2003-01-01

    There are more than 20 electron accelerators in Korea. Most of those are installed in factories for heat-resistant cables, heat-shrinkable cables, radial tires, foams, tube/ films, curing, etc. Four low-energy electron accelerators are in operation for research purposes such as polymer modification, purification of flue gas, waste water treatment, modification of semiconductor characteristics, etc. (author)

  8. Utilization of low-energy electron accelerators in Korea

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Byung Cheol [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    2003-02-01

    There are more than 20 electron accelerators in Korea. Most of those are installed in factories for heat-resistant cables, heat-shrinkable cables, radial tires, foams, tube/ films, curing, etc. Four low-energy electron accelerators are in operation for research purposes such as polymer modification, purification of flue gas, waste water treatment, modification of semiconductor characteristics, etc. (author)

  9. Numerical simulation on range of high-energy electron moving in accelerator target

    International Nuclear Information System (INIS)

    Shao Wencheng; Sun Punan; Dai Wenjiang

    2008-01-01

    In order to determine the range of high-energy electron moving in accelerator target, the range of electron with the energy range of 1 to 100 MeV moving in common target material of accelerator was calculated by Monte-Carlo method. Comparison between the calculated result and the published data were performed. The results of Monte-Carlo calculation are in good agreement with the published data. Empirical formulas were obtained for the range of high-energy electron with the energy range of 1 to 100 MeV in common target material by curve fitting, offering a series of referenced data for the design of targets in electron accelerator. (authors)

  10. Stability of electron-beam energy monitor for quality assurance of the electron-beam energy from radiotherapy accelerators

    International Nuclear Information System (INIS)

    Chida, Koichi; Zuguchi, Masayuki; Saito, Haruo; Takai, Yoshihiro; Mitsuya, Masatoshi; Sakakida, Hideharu; Yamada, Shogo; Kohzuki, Masahiro

    2002-01-01

    Information on electron energy is important in planning radiation therapy using electrons. The Geske 3405 electron beam energy monitor (Geske monitor, PTW Nuclear Associates, Carle Place, NY, USA) is a device containing nine ionization chambers for checking the energy of the electron beams produced by radiotherapy accelerators. We wondered whether this might increase the likelihood of ionization chamber trouble. In spite of the importance of the stability of such a quality assurance (QA) device, there are no reports on the stability of values measured with a Geske monitor. The purpose of this paper was therefore to describe the stability of a Geske monitor. It was found that the largest coefficient of variation (CV) of the Geske monitor measurements was approximately 0.96% over a 21-week period. In conclusion, the stability of Geske monitor measurements of the energy of electron beams from a linear accelerator was excellent. (author)

  11. High energy electron acceleration with PW-class laser system

    International Nuclear Information System (INIS)

    Nakanii, N.; Kondo, K.; Yabuuchi, T.; Tsuji, K.; Kimura, K.; Fukumochi, S.; Kashihara, M.; Tanimoto, T.; Nakamura, H.; Ishikura, T.; Kodama, R.; Mima, K.; Tanaka, K. A.; Mori, Y.; Miura, E.; Suzuki, S.; Asaka, T.; Yanagida, K.; Hanaki, H.; Kobayashi, T.

    2008-01-01

    We performed electron acceleration experiment with PW-class laser and a plasma tube, which was created by imploding a hollow polystyrene cylinder. In this experiment, electron energies in excess of 600 MeV have been observed. Moreover, the spectra of a comparatively high-density plasma ∼10 19 cm -3 had a bump around 10 MeV. Additionally, we performed the absolute sensitivity calibration of imaging plate for 1 GeV electrons from the injector Linac of Spring-8 in order to evaluate absolute number of GeV-class electrons in the laser acceleration experiment

  12. The electron accelerator Ridgetron

    International Nuclear Information System (INIS)

    Hayashizaki, N.; Hattori, T.; Odera, M.; Fujisawa, T.

    1999-01-01

    Many electron accelerators of DC or RF type have been widely used for electron beam irradiation (curing, crosslinking of polymers, sterilization of medical disposables, preservation of food, etc.). Regardless of the acceleration energy, the accelerators to be installed in industrial facilities, have to satisfy the requires of compact size, low power consumption and stable operation. The DC accelerator is realized very compact in the energy under 300 keV, however, it is large to prevent the discharge of an acceleration column in the energy over 300 keV. The RF electron accelerator Ridgetron has been developed to accelerate the continuous beam of the 0.5-10 MeV range in compact space. It is the first example as an electron accelerator incorporated a ridged RF cavity. A prototype system of final energy of 2.5 MeV has been studied to confirm the feasibility at present

  13. The application analysis of high energy electron accelerator in food irradiation processing

    International Nuclear Information System (INIS)

    Deng Wenmin; Chen Hao; Feng Lei; Zhang Yaqun; Chen Xun; Li Wenjun; Xiang Chengfen; Pei Ying; Wang Zhidong

    2012-01-01

    Irradiation technology of high energy electron accelerator has been highly concerned in food processing industry with its fast development, especially in the field of food irradiation processing. In this paper, equipment and research situation of high energy electron accelerator were collected, meanwhile, the similarities and differences between high energy electron beam and 60 Co γ-rays were discussed. In order to provide more references of high energy electron beam irradiation, the usages of high energy electron in food irradiation processing was prospected. These information would promote the development of domestic food irradiation industry and give a useful message to irradiation enterprises and researchers. (authors)

  14. Study of electron beam energy conversion at gyrocon-linear accelerator facility

    International Nuclear Information System (INIS)

    Karliner, M.M.; Makarov, I.G.; Ostreiko, G.N.

    2004-01-01

    A gyrocon together with the high-voltage 1.5 MeV accelerator ELIT-3A represents a power generator at 430 MHz serving for linear electron accelerator pulse driving. The facility description and results of calorimetric measurements of ELIT-3A electron beam power and accelerated beam at the end of accelerator are presented in the paper. The achieved energy conversion efficiency is about 55%

  15. Success and prospects for low energy, self-shielded electron beam accelerators

    International Nuclear Information System (INIS)

    Laeuppi, U.V.

    1988-01-01

    The advantages of self-shielded, low energy, electron beam accelerators for electron beam processing are described. Applications of these accelerators for cross-linking plastic films, drying of coated materials and printing inks and for curing processes are discussed. (U.K.)

  16. Shielding for high energy, high intensity electron accelerator installation

    International Nuclear Information System (INIS)

    Warawas, C.; Chongkum, S.

    1997-03-01

    The utilization of electron accelerators (eBA) is gradually increased in Thailand. For instance, a 30-40 MeV eBA are used for tumor and cancer therapy in the hospitals, and a high current eBA in for gemstone colonization. In the near future, an application of eBA in industries will be grown up in a few directions, e.g., flue gases treatment from the coal fire-power plants, plastic processing, rubber vulcanization and food preservation. It is the major roles of Office of Atomic Energy for Peace (OAEP) to promote the peaceful uses of nuclear energy and to regulate the public safety and protection of the environment. By taking into account of radiation safety aspect, high energy electrons are not only harmful to human bodies, but the radioactive nuclides can be occurred. This report presents a literature review by following the National Committee on Radiation Protection and Measurements (NCRP) report No.31. This reviews for parametric calculation and shielding design of the high energy (up to 100 MeV), high intensity electron accelerator installation

  17. High-energy inverse free-electron laser accelerator

    International Nuclear Information System (INIS)

    Courant, E.D.; Pellegrini, C.; Zakowicz, W.

    1985-01-01

    We study the inverse free electron laser (IFEL) accelerator and show that it can accelerate electrons to the few hundred GeV region with average acceleration rates of the order of 200 meV/m. Several possible accelerating structures are analyzed, and the effect of synchrotron radiation losses is studied. The longitudinal phase stability of accelerated particles is also analyzed. A Hamiltonian description, which takes into account the dissipative features of the IFEL accelerator, is introduced to study perturbations from the resonant acceleration. Adiabatic invariants are obtained and used to estimate the change of the electron phase space density during the acceleration process

  18. Luminescent tracks of high-energy photoemitted electrons accelerated by plasmonic fields

    Directory of Open Access Journals (Sweden)

    Di Vece Marcel

    2015-12-01

    Full Text Available The emission of an electron from a metal nanostructure under illumination and its subsequent acceleration in a plasmonic field forms a platform to extend these phenomena to deposited nanoparticles, which can be studied by state-of-the-art confocal microscopy combined with femtosecond optical excitation. The emitted and accelerated electrons leave defect tracks in the immersion oil, which can be revealed by thermoluminescence. These photographic tracks are read out with the confocal microscope and have a maximum length of about 80 μm, which corresponds to a kinetic energy of about 100 keV. This energy is consistent with the energy provided by the intense laser pulse combined with plasmonic local field enhancement. The results are discussed within the context of the rescattering model by which electrons acquire more energy. The visualization of electron tracks originating from plasmonic field enhancement around a gold nanoparticle opens a new way to study with confocal microscopy both the plasmonic properties of metal nano objects as well as high energy electron interaction with matter.

  19. Acceleration of polarized electrons in the Bonn electron-accelerator facility ELSA

    International Nuclear Information System (INIS)

    Hoffmann, M.

    2001-12-01

    The future medium energy physics program at the electron stretcher accelerator ELSA of Bonn University mainly relies on experiments using polarized electrons in the energy range from 1 to 3.2 GeV. To prevent depolarization during acceleration in the circular accelerators several depolarizing resonances have to be corrected for. Intrinsic resonances are compensated using two pulsed betatron tune jump quadrupoles. The influence of imperfection resonances is successfully reduced applying a dynamic closed orbit correction in combination with an empirical harmonic correction on the energy ramp. Both types of resonances and the correction techniques have been studied in detail. The imperfection resonances were used to calibrate the energy of the stretcher ring with high accuracy. A new technique to extract the beam with horizontal oriented polarization was successfully installed. For all energies a polarized electron beam with more than 50% polarization can now be supplied to the experiments at ELSA, which is demonstrated by measurements using a Moeller polarimeter installed in the external beamline. (orig.)

  20. Acceleration of electrons using an inverse free electron laser auto- accelerator

    International Nuclear Information System (INIS)

    Wernick, I.K.; Marshall, T.C.

    1992-07-01

    We present data from our study of a device known as the inverse free electron laser. First, numerical simulations were performed to optimize the design parameters for an experiment that accelerates electrons in the presence of an undulator by stimulated absorption of radiation. The Columbia free electron laser (FEL) was configured as an auto-accelerator (IFELA) system; high power (MW's) FEL radiation at ∼1.65 mm is developed along the first section of an undulator inside a quasi-optical resonator. The electron beam then traverses a second section of undulator where a fraction of the electrons is accelerated by stimulated absorption of the 1.65 mm wavelength power developed in the first undulator section. The second undulator section has very low gain and does not generate power on its own. We have found that as much as 60% of the power generated in the first section can be absorbed in the second section, providing that the initial electron energy is chosen correctly with respect to the parameters chosen for the first and second undulators. An electron momentum spectrometer is used to monitor the distribution of electron energies as the electrons exit the IFELA. We have found; using our experimental parameters, that roughly 10% of the electrons are accelerated to energies as high as 1100 keV, in accordance with predictions from the numerical model. The appearance of high energy electrons is correlated with the abrupt absorption of millimeter power. The autoaccelerator configuration is used because there is no intense source of coherent power at the 1.65 mm design wavelength other than the FEL

  1. Electron accelerator

    International Nuclear Information System (INIS)

    Abramyan.

    1981-01-01

    The USSR produces an electron accelerator family of a simple design powered straight from the mains. The specifications are given of accelerators ELITA-400, ELITA-3, ELT-2, TEUS-3 and RIUS-5 with maximum electron energies of 0.3 to 5 MeV, a mean power of 10 to 70 kW operating in both the pulsed and the continuous (TEUS-3) modes. Pulsed accelerators ELITA-400 and ELITA-3 and RIUS-5 in which TESLA resonance transformers are used are characterized by their compact size. (Ha)

  2. Enhancement of electron energy during vacuum laser acceleration in an inhomogeneous magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Saberi, H.; Maraghechi, B., E-mail: behrouz@aut.ac.ir [Department of Physics, Amirkabir University of Technology, 15875-4413 Tehran (Iran, Islamic Republic of)

    2015-03-15

    In this paper, the effect of a stationary inhomogeneous magnetic field on the electron acceleration by a high intensity Gaussian laser pulse is investigated. A focused TEM (0,0) laser mode with linear polarization in the transverse x-direction that propagates along the z-axis is considered. The magnetic field is assumed to be stationary in time, but varies longitudinally in space. A linear spatial profile for the magnetic field is adopted. In other words, the axial magnetic field increases linearly in the z-direction up to an optimum point z{sub m} and then becomes constant with magnitude equal to that at z{sub m}. Three-dimensional single-particle simulations are performed to find the energy and trajectory of the electron. The electron rotates around and stays near the z-axis. It is shown that with a proper choice of the magnetic field parameters, the electron will be trapped at the focus of the laser pulse. Because of the cyclotron resonance, the electron receives enough energy from the laser fields to be accelerated to relativistic energies. Using numerical simulations, the criteria for optimum regime of the acceleration mechanism is found. With the optimized parameters, an electron initially at rest located at the origin achieves final energy of γ=802. The dynamics of a distribution of off-axis electrons are also investigated in which shows that high energy electrons with small energy and spatial spread can be obtained.

  3. Treatment planning for laser-accelerated very-high energy electrons

    International Nuclear Information System (INIS)

    Fuchs, T; Szymanowski, H; Oelfke, U; Glinec, Y; Rechatin, C; Faure, J; Malka, V

    2009-01-01

    In recent experiments, quasi-monoenergetic and well-collimated very-high energy electron (VHEE) beams were obtained by laser-plasma accelerators. We investigate their potential use for radiation therapy. Monte Carlo simulations are used to study the influence of the experimental characteristics such as beam energy, energy spread and initial angular distribution on the dose distributions. It is found that magnetic focusing of the electron beam improves the lateral penumbra. The dosimetric properties of the laser-accelerated VHEE beams are implemented in our inverse treatment planning system for intensity-modulated treatments. The influence of the beam characteristics on the quality of a prostate treatment plan is evaluated. In comparison to a clinically approved 6 MV IMRT photon plan, a better target coverage is achieved. The quality of the sparing of organs at risk is found to be dependent on the depth. The bladder and rectum are better protected due to the sharp lateral penumbra at low depths, whereas the femoral heads receive a larger dose because of the large scattering amplitude at larger depths.

  4. Fixed-Target Electron Accelerators

    International Nuclear Information System (INIS)

    Brooks, William K.

    2001-01-01

    A tremendous amount of scientific insight has been garnered over the past half-century by using particle accelerators to study physical systems of sub-atomic dimensions. These giant instruments begin with particles at rest, then greatly increase their energy of motion, forming a narrow trajectory or beam of particles. In fixed-target accelerators, the particle beam impacts upon a stationary sample or target which contains or produces the sub-atomic system being studied. This is in distinction to colliders, where two beams are produced and are steered into each other so that their constituent particles can collide. The acceleration process always relies on the particle being accelerated having an electric charge; however, both the details of producing the beam and the classes of scientific investigations possible vary widely with the specific type of particle being accelerated. This article discusses fixed-target accelerators which produce beams of electrons, the lightest charged particle. As detailed in the report, the beam energy has a close connection with the size of the physical system studied. Here a useful unit of energy is a GeV, i.e., a giga electron-volt. (ne GeV, the energy an electron would have if accelerated through a billion volts, is equal to 1.6 x 10 -10 joules.) To study systems on a distance scale much smaller than an atomic nucleus requires beam energies ranging from a few GeV up to hundreds of GeV and more

  5. Resent advance in electron linear accelerators

    International Nuclear Information System (INIS)

    Takeda, Seishi; Tsumori, Kunihiko; Takamuku, Setsuo; Okada, Toichi; Hayashi, Koichiro; Kawanishi, Masaharu

    1986-01-01

    In recently constructed electron linear accelerators, there has been remarkable advance both in acceleration of a high-current single bunch electron beam for radiation research and in generation of high accelerating gradient for high energy accelerators. The ISIR single bunch electron linear accelerator has been modified an injector to increase a high-current single bunch charge up to 67 nC, which is ten times greater than the single bunch charge expected in early stage of construction. The linear collider projects require a high accelerating gradient of the order of 100 MeV/m in the linear accelerators. High-current and high-gradient linear accelerators make it possible to obtain high-energy electron beam with small-scale linear accelerators. The advance in linear accelerators stimulates the applications of linear accelerators not only to fundamental research of science but also to industrial uses. (author)

  6. Radiation protection of the operation of accelerator facilities. On high energy proton and electron accelerators

    International Nuclear Information System (INIS)

    Kondo, Kenjiro

    1997-01-01

    Problems in the radiation protection raised by accelerated particles with energy higher than several hundreds MeV in strong accelerator facilities were discussed in comparison with those with lower energy in middle- and small-scale facilities. The characteristics in the protection in such strong accelerator facilities are derived from the qualitative changes in the interaction between the high energy particles and materials and from quantitative one due to the beam strength. In the former which is dependent on the emitting mechanism of the radiation, neutron with broad energy spectrum and muon are important in the protection, and in the latter, levels of radiation and radioactivity which are proportional to the beam strength are important. The author described details of the interaction between high energy particles and materials: leading to the conclusion that in the electron accelerator facilities, shielding against high energy-blemsstrahlung radiation and -neutron is important and in the proton acceleration, shielding against neutron is important. The characteristics of the radiation field in the strong accelerator facilities: among neutron, ionized particles and electromagnetic wave, neutron is most important in shielding since it has small cross sections relative to other two. Considerations for neutron are necessary in the management of exposure. Multiplicity of radionuclides produced: which is a result of nuclear spallation reaction due to high energy particles, especially to proton. Radioactivation of the accelerator equipment is a serious problem. Other problems: the interlock systems, radiation protection for experimenters and maintenance of the equipment by remote systems. (K.H.). 11 refs

  7. The use of low energy electron accelerator for processing of liquid matter in Indonesia

    International Nuclear Information System (INIS)

    Danu, Sugiarto

    2003-01-01

    Activities of radiation processing in Indonesia covering various fields are reviewed. The low and medium energy electron accelerator specially designed for radiation processing of liquid materials is introduced. P3TIR-BATAN is mostly engaged in radiation processing in general with Co-60 source and electron accelerators (300 keV, 50 mA and 2 MeV, 10 mA). A private company, Gajah Tunggal, has an accelerator of 500 keV, 20 mA. The use of low energy electron accelerator to irradiate liquid matter matter such as natural rubber latex, polysaccharides, starch, chitosan and other natural polymers in Indonesia are reported and future program of national research cooperation between government institutions and private companies are described. (S. Ohno)

  8. Project of the electron linear accelerator on the biperiodical accelerating structure with deep energy retuning in a pulse mode

    International Nuclear Information System (INIS)

    Bogdanovich, B.Yu.; Zavadtsev, D.A.; Kaminskij, V.I.; Sobenin, N.P.; Fadin, A.I.; Zavadtsev, A.A.

    2001-01-01

    The schemes of the electron linear accelerator (ELA), realized on the basis of a biperiodical accelerating structure and ensuring the possibility of deep retuning of the beam energy in a pulse mode, are considered. Advantages and shortcomings of the proposed methods of pulse regulation of the electron energy are discussed. A project of a two-section ELA with two levels of energy (10 and 4 MeV) is presented as a base version. The beam dynamics is calculated for two versions of the ELA. Their main parameters are given [ru

  9. Radiation vulcanization of natural rubber latex (NRL) using low energy electron beam accelerator

    International Nuclear Information System (INIS)

    Feroza Akhtar; Keizo Makuuchi; Fumio Yoshii

    1996-01-01

    The electron beam induced vulcanization of natural rubber latex has been studied using low energy Electron Beam (EB) accelerators of 300, 250 and 175 keV ne latex was irradiated in a special type stainless steel reaction reactor with a stirrer at the bottom of the reactor. From the results it was found that 300 and 250 keV accelerators could effectively vulcanize NRL. But accelerator of 175 keV is too low energy to vulcanize the latex. At the same time a drum type irradiator where thin layer of NRL was irradiated by accelerator, was used for vulcanization of NRL. This type of irradiator also showed good physical properties of vulcanized latex. The effects of beam current and stirrer speed on vulcanization were studied

  10. Application of electron accelerator worldwide

    International Nuclear Information System (INIS)

    Machi, Sueo

    2003-01-01

    Electron accelerator is an important radiation source for radiation technology, which covers broad fields such as industry, health care, food and environmental protection. There are about 1,000 electron accelerators for radiation processing worldwide. Electron accelerator has advantage over Co-60 irradiator in term of high dose rate and power, assurance of safety, and higher economic performance at larger volume of irradiation. Accelerator generating higher energy in the range of 10 MeV and high power electron beam is now commercially available. There is a trend to use high-energy electron accelerator replacing Co-60 in case of large through-put of medical products. Irradiated foods, in particular species, are on the commercial market in 35 countries. Electron accelerator is used efficiently and economically for production of new or modified polymeric materials through radiation-induced cross-linking, grafting and polymerization reaction. Another important application of electron beam is the curing of surface coatings in the manufacture of products. Electron accelerators of large capacity are used for cleaning exhaust gases in industrial scale. Economic feasibility studies of this electron beam process have shown that this technology is more cost effective than the conventional process. It should be noted that the conventional limestone process produce gypsum as a by-product, which cannot be used in some countries. By contrast, the by-product of the electron beam process is a valuable fertilizer. (Y. Tanaka)

  11. Application of electron accelerator worldwide

    Energy Technology Data Exchange (ETDEWEB)

    Machi, Sueo [Japan Atomic Industrial Forum, Inc., Tokyo (Japan)

    2003-02-01

    Electron accelerator is an important radiation source for radiation technology, which covers broad fields such as industry, health care, food and environmental protection. There are about 1,000 electron accelerators for radiation processing worldwide. Electron accelerator has advantage over Co-60 irradiator in term of high dose rate and power, assurance of safety, and higher economic performance at larger volume of irradiation. Accelerator generating higher energy in the range of 10 MeV and high power electron beam is now commercially available. There is a trend to use high-energy electron accelerator replacing Co-60 in case of large through-put of medical products. Irradiated foods, in particular species, are on the commercial market in 35 countries. Electron accelerator is used efficiently and economically for production of new or modified polymeric materials through radiation-induced cross-linking, grafting and polymerization reaction. Another important application of electron beam is the curing of surface coatings in the manufacture of products. Electron accelerators of large capacity are used for cleaning exhaust gases in industrial scale. Economic feasibility studies of this electron beam process have shown that this technology is more cost effective than the conventional process. It should be noted that the conventional limestone process produce gypsum as a by-product, which cannot be used in some countries. By contrast, the by-product of the electron beam process is a valuable fertilizer. (Y. Tanaka)

  12. The auroral electron accelerator

    International Nuclear Information System (INIS)

    Bryant, D.A.; Hall, D.S.

    1989-01-01

    A model of the auroral electron acceleration process is presented in which the electrons are accelerated resonantly by lower-hybrid waves. The essentially stochastic acceleration process is approximated for the purposes of computation by a deterministic model involving an empirically derived energy transfer function. The empirical function, which is consistent with all that is known of electron energization by lower-hybrid waves, allows many, possibly all, observed features of the electron distribution to be reproduced. It is suggested that the process occurs widely in both space and laboratory plasmas. (author)

  13. Two-dimensional angular energy spectrum of electrons accelerated by the ultra-short relativistic laser pulse

    Energy Technology Data Exchange (ETDEWEB)

    Borovskiy, A. V. [Department of Computer Science and Cybernetics, Baikal State University of Economics and Law, 11 Lenin Street, Irkutsk 664003 (Russian Federation); Galkin, A. L. [Coherent and Nonlinear Optics Department, A.M. Prokhorov General Physics Institute of the RAS, 38 Vavilov Street, Moscow 119991 (Russian Federation); Department of Physics of MBF, Pirogov Russian National Research Medical University, 1 Ostrovitianov Street, Moscow 117997 (Russian Federation); Kalashnikov, M. P., E-mail: galkin@kapella.gpi.ru [Max-Born-Institute for Nonlinear Optics and Short-Time Spectroscopy, 2a Max-Born-Strasse, Berlin 12489 (Germany)

    2015-04-15

    The new method of calculating energy spectra of accelerated electrons, based on the parameterization by their initial coordinates, is proposed. The energy spectra of electrons accelerated by Gaussian ultra-short relativistic laser pulse at a selected angle to the axis of the optical system focusing the laser pulse in a low density gas are theoretically calculated. The two-peak structure of the electron energy spectrum is obtained. Discussed are the reasons for its appearance as well as an applicability of other models of the laser field.

  14. Electron clouds in high energy hadron accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Petrov, Fedor

    2013-08-29

    The formation of electron clouds in accelerators operating with positrons and positively charge ions is a well-known problem. Depending on the parameters of the beam the electron cloud manifests itself differently. In this thesis the electron cloud phenomenon is studied for the CERN Super Proton Synchrotron (SPS) and Large Hadron Collider (LHC) conditions, and for the heavy-ion synchrotron SIS-100 as a part of the FAIR complex in Darmstadt, Germany. Under the FAIR conditions the extensive use of slow extraction will be made. After the acceleration the beam will be debunched and continuously extracted to the experimental area. During this process, residual gas electrons can accumulate in the electric field of the beam. If this accumulation is not prevented, then at some point the beam can become unstable. Under the SPS and LHC conditions the beam is always bunched. The accumulation of electron cloud happens due to secondary electron emission. At the time when this thesis was being written the electron cloud was known to limit the maximum intensity of the two machines. During the operation with 25 ns bunch spacing, the electron cloud was causing significant beam quality deterioration. At moderate intensities below the instability threshold the electron cloud was responsible for the bunch energy loss. In the framework of this thesis it was found that the instability thresholds of the coasting beams with similar space charge tune shifts, emittances and energies are identical. First of their kind simulations of the effect of Coulomb collisions on electron cloud density in coasting beams were performed. It was found that for any hadron coasting beam one can choose vacuum conditions that will limit the accumulation of the electron cloud below the instability threshold. We call such conditions the ''good'' vacuum regime. In application to SIS-100 the design pressure 10{sup -12} mbar corresponds to the good vacuum regime. The transition to the bad vacuum

  15. Need for accelerating electrons

    International Nuclear Information System (INIS)

    Kerst, D.W.

    1987-01-01

    Photons for nuclear disintegration experiments were not abundantly available in the early days of nuclear physics, whereas accelerated ions led the way. When electrons could be accelerated into the 20--30 MeV range, they found application not only to nuclear disintegration of the elements of the periodic table but also to x-ray radiography and to deep therapy. Energies of interest for probing nuclear structure by electron scattering and for meson production followed soon after. The elementary nature of the electron has now made it a valuable tool for present day particle physics; and the synchrotron radiation, which is an obstacle for some accelerating processes, has become a much sought after source of photons for experiments at atomic structure energies

  16. Application of pulse power technology to ultra high energy electron accelerators

    International Nuclear Information System (INIS)

    Nation, J.A.

    1989-01-01

    The author presents in this paper a review of the application of pulse power technology to the development of high gradient electron accelerators. The technology demands are relatively modest compared to the ultra high power technology used for inertial confinement fusion drivers. With the advent of magnetic switching intense electron beams can be generated with a sufficiently high repetition rate to be of interest for high energy electron accelerator driver applications. Most of the techniques considered rely on the excitation of large amplitude waves on the beams. Within this framework there are two broad categories of accelerator, those in which the waves are directly excited in and supported by the medium and, secondly, those where the waves are used to generate radiofrequency signals which are then coupled via structures to the beam being accelerated. In what follows we shall consider both approaches. Present-day pulse power technology limits pulse durations to about 100 nsec. Consequently, if these sources are to be used, we will need to use high group velocity structures to avoid the need for short accelerator module lengths. An advantage of the short pulse duration is that the available acceleration voltage gradient increases compared to that obtained using conventional rf drivers. 19 references, 9 figures, 1 table

  17. Picosecond, single pulse electron linear accelerator

    International Nuclear Information System (INIS)

    Kikuchi, Riichi; Kawanishi, Masaharu

    1979-01-01

    The picosecond, single pulse electron linear accelerators, are described, which were installed in the Nuclear Engineering Laboratory of the University of Tokyo and in the Nuclear Radiation Laboratory of the Osaka University. The purpose of the picosecond, single pulse electron linear accelerators is to investigate the very short time reaction of the substances, into which gamma ray or electron beam enters. When the electrons in substances receive radiation energy, the electrons get high kinetic energy, and the energy and the electric charge shift, at last to the quasi-stable state. This transient state can be experimented with these special accelerators very accurately, during picoseconds, raising the accuracy of the time of incidence of radiation and also raising the accuracy of observation time. The outline of these picosecond, single pulse electron linear accelerators of the University of Tokyo and the Osaka University, including the history, the systems and components and the output beam characteristics, are explained. For example, the maximum energy 30 -- 35 MeV, the peak current 1 -- 8 n C, the pulse width 18 -- 40 ps, the pulse repetition rate 200 -- 720 pps, the energy spectrum 1 -- 1.8% and the output beam diameter 2 -- 5 mm are shown as the output beam characteristics of the accelerators in both universities. The investigations utilizing the picosecond single pulse electron linear accelerators, such as the investigation of short life excitation state by pulsed radiation, the dosimetry study of pulsed radiation, and the investigation of the transforming mechanism and the development of the transforming technology from picosecond, single pulse electron beam to X ray, vacuum ultraviolet ray and visual ray, are described. (Nakai, Y.)

  18. Accelerators for energy

    International Nuclear Information System (INIS)

    Inoue, Makoto

    2000-01-01

    A particle accelerator is a device to consume energy but not to produce it. Then, the titled accelerator seems to mean an accelerator for using devices related to nuclear energy. For an accelerator combined to nuclear fissionable fuel, neutron sources are D-T type, (gamma, n) reaction using electron beam type spallation type, and so forth. At viewpoints of powers of incident beam and formed neutron, a spallation type source using high energy proton is told to be effective but others have some advantages by investigation on easy operability, easy construction, combustion with target, energy and directivity of neutron, and so forth. Here were discussed on an accelerator for research on accelerator driven energy system by dividing its researching steps, and on kind, energy, beam intensity, and so forth of an accelerator suitable for it. And, space electric charge effect at beam propagation direction controlled by beam intensity of cyclotron was also commented. (G.K.)

  19. The operational procedure of an electron beam accelerator

    International Nuclear Information System (INIS)

    Lee, Byung Cheol; Choi, Hwa Lim; Yang, Ki Ho; Han, Young Hwan; Kim, Sung Chan

    2008-12-01

    The KAERI(Korea Atomic Energy of Research Institute) high-power electron beam irradiation facility, operating at the energies between 0.3 MeV and 10 MeV, has provided irradiation services to users in industries, universities, and institute in various fields. This manual is for the operation of an electron beam which is established in KAERI, and describes elementary operation procedures of electron beam between 0.3 Mev and 10 MeV. KAERI Electron Accelerator facility(Daejeon, Korea) consists of two irradiators: one is a low-energy electron beam irradiator operated by normal conducting RF accelerator, the other is medium-energy irradiator operated by superconducting RF accelerator. We explain the check points of prior to operation, operation procedure of this facility and the essential parts of electron beam accelerator

  20. The operational procedure of an electron beam accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Byung Cheol; Choi, Hwa Lim; Yang, Ki Ho; Han, Young Hwan; Kim, Sung Chan

    2008-12-15

    The KAERI(Korea Atomic Energy of Research Institute) high-power electron beam irradiation facility, operating at the energies between 0.3 MeV and 10 MeV, has provided irradiation services to users in industries, universities, and institute in various fields. This manual is for the operation of an electron beam which is established in KAERI, and describes elementary operation procedures of electron beam between 0.3 Mev and 10 MeV. KAERI Electron Accelerator facility(Daejeon, Korea) consists of two irradiators: one is a low-energy electron beam irradiator operated by normal conducting RF accelerator, the other is medium-energy irradiator operated by superconducting RF accelerator. We explain the check points of prior to operation, operation procedure of this facility and the essential parts of electron beam accelerator.

  1. Laser vacuum acceleration of a relativistic electron bunch

    Energy Technology Data Exchange (ETDEWEB)

    Glazyrin, I V; Karpeev, A V; Kotova, O G; Nazarov, K S [E.I. Zababakhin All-Russian Scientific-Research Institute of Technical Physics, Russian Federal Nuclear Centre, Snezhinsk, Chelyabinsk region (Russian Federation); Bychenkov, V Yu [P N Lebedev Physics Institute, Russian Academy of Sciences, Moscow (Russian Federation)

    2015-06-30

    With regard to the problem of laser acceleration of a relativistic electron bunch we present a scheme of its vacuum acceleration directly by a relativistic intensity laser pulse. The energy of the electron bunch injected into the laser pulse leading edge increases during its coaxial movement to a thin, pulse-reflecting target. The laser-accelerated electrons continue to move free forward, passing through the target. The study of this acceleration scheme in the three-dimensional geometry is verified in a numerical simulation by the particle-in-cell method, which showed that the energy of a part of the electrons can increase significantly compared to the initial one. Restrictions are discussed, which impose limiting values of energy and total charge of accelerated electrons. (superstrong light fields)

  2. Electron cyclotron harmonic wave acceleration

    Science.gov (United States)

    Karimabadi, H.; Menyuk, C. R.; Sprangle, P.; Vlahos, L.

    1987-01-01

    A nonlinear analysis of particle acceleration in a finite bandwidth, obliquely propagating electromagnetic cyclotron wave is presented. It has been suggested by Sprangle and Vlahos in 1983 that the narrow bandwidth cyclotron radiation emitted by the unstable electron distribution inside a flaring solar loop can accelerate electrons outside the loop by the interaction of a monochromatic wave propagating along the ambient magnetic field with the ambient electrons. It is shown here that electrons gyrating and streaming along a uniform, static magnetic field can be accelerated by interacting with the fundamental or second harmonic of a monochromatic, obliquely propagating cyclotron wave. It is also shown that the acceleration is virtually unchanged when a wave with finite bandwidth is considered. This acceleration mechanism can explain the observed high-energy electrons in type III bursts.

  3. Electron cyclotron harmonic wave acceleration

    International Nuclear Information System (INIS)

    Karimabadi, H.; Menyuk, C.R.; Sprangle, P.; Vlahos, L.; Salonika Univ., Greece)

    1987-01-01

    A nonlinear analysis of particle acceleration in a finite bandwidth, obliquely propagating electromagnetic cyclotron wave is presented. It has been suggested by Sprangle and Vlahos in 1983 that the narrow bandwidth cyclotron radiation emitted by the unstable electron distribution inside a flaring solar loop can accelerate electrons outside the loop by the interaction of a monochromatic wave propagating along the ambient magnetic field with the ambient electrons. It is shown here that electrons gyrating and streaming along a uniform, static magnetic field can be accelerated by interacting with the fundamental or second harmonic of a monochromatic, obliquely propagating cyclotron wave. It is also shown that the acceleration is virtually unchanged when a wave with finite bandwidth is considered. This acceleration mechanism can explain the observed high-energy electrons in type III bursts. 31 references

  4. Electron acceleration by turbulent plasmoid reconnection

    Science.gov (United States)

    Zhou, X.; Büchner, J.; Widmer, F.; Muñoz, P. A.

    2018-04-01

    In space and astrophysical plasmas, like in planetary magnetospheres, as that of Mercury, energetic electrons are often found near current sheets, which hint at electron acceleration by magnetic reconnection. Unfortunately, electron acceleration by reconnection is not well understood yet, in particular, acceleration by turbulent plasmoid reconnection. We have investigated electron acceleration by turbulent plasmoid reconnection, described by MHD simulations, via test particle calculations. In order to avoid resolving all relevant turbulence scales down to the dissipation scales, a mean-field turbulence model is used to describe the turbulence of sub-grid scales and their effects via a turbulent electromotive force (EMF). The mean-field model describes the turbulent EMF as a function of the mean values of current density, vorticity, magnetic field as well as of the energy, cross-helicity, and residual helicity of the turbulence. We found that, mainly around X-points of turbulent reconnection, strongly enhanced localized EMFs most efficiently accelerated electrons and caused the formation of power-law spectra. Magnetic-field-aligned EMFs, caused by the turbulence, dominate the electron acceleration process. Scaling the acceleration processes to parameters of the Hermean magnetotail, electron energies up to 60 keV can be reached by turbulent plasmoid reconnection through the thermal plasma.

  5. Electron accelerators: History, applications, and perspectives

    International Nuclear Information System (INIS)

    Martins, M.N.; Silva, T.F.

    2014-01-01

    This paper will present an outlook on sources of radiation, focusing on electron accelerators. We will review advances that were important for the development of particle accelerators, concentrating on those that led to modern electron accelerators. Electron accelerators are multipurpose machines that deliver beams with energies spanning five orders of magnitude, and are used in applications that range from fundamental studies of particle interactions to cross-linking polymer chains in industrial plants. Each accelerator type presents specific characteristics that make it more suitable for certain applications. Our work will focus on radiation sources for medical applications, dominated by electron linacs (linear accelerators), and those used for research, field where electron rings dominate. We will outline the main technological advances that occurred in the past decades, which made possible the construction of machines fit for clinical environments. Their compactness, efficiency and reliability have been key to their acceptance in clinical applications. This outline will include advances that allowed for the construction of brighter synchrotron light sources, where the relevant beam characteristics are good optical quality and high beam current. The development of insertion devices will also be discussed, as well the development of Free Electron Lasers (FEL). We conclude the review with an outline of the new developments of electron accelerators and the expectations for Energy Recovery Linacs. - Highlights: ► We present an outlook on sources of radiation, focusing on electron accelerators. ► We review important advances for the development of modern electron accelerators. ► We outline advances that allowed for brighter synchrotron light sources. ► We describe the history of the development of electron accelerators in Brazil

  6. Ion acceleration in modulated electron beams

    International Nuclear Information System (INIS)

    Bonch-Osmolovskij, A.G.; Dolya, S.N.

    1977-01-01

    A method of ion acceleration in modulated electron beams is considered. Electron density and energy of their rotational motion are relatively low. However the effective ion-accelerating field is not less than 10 MeV/m. The electron and ion numbers in an individual bunch are also relatively small, although the number of produced bunches per time unit is great. Some aspects of realization of the method are considered. Possible parameters of the accelerator are given. At 50 keV electron energy and 1 kA beam current a modulation is realized at a wave length of 30 cm. The ion-accelerating field is 12 MeV/m. The bunch number is 2x10 3 in one pulse at a gun pulse duration of 2 μs. With a pulse repetition frequency of 10 2 Hz the number of accelerated ions can reach 10 13 -10 14 per second

  7. A Low-Energy-Spread Rf Accelerator for a Far-Infrared Free-Electron Laser

    NARCIS (Netherlands)

    van der Geer, C. A. J.; Bakker, R. J.; van der Meer, A. F. G.; van Amersfoort, P. W.; Gillespie, W. A.; Saxon, G.; Poole, M. W.

    1993-01-01

    A high electron current and a small energy spread are essential for the operation of a free electron laser (FEL). In this paper we discuss the design and performance of the accelerator for FELIX, the free electron laser for infrared experiments. The system consists of a thermionic gun, a prebuncher,

  8. Permanent-magnet energy spectrometer for electron beams from radiotherapy accelerators

    Energy Technology Data Exchange (ETDEWEB)

    McLaughlin, David J.; Shikhaliev, Polad M.; Matthews, Kenneth L. [Department of Physics and Astronomy, Louisiana State University, 202 Nicholson Hall, Baton Rouge, Louisiana 70803-4001 (United States); Hogstrom, Kenneth R., E-mail: hogstrom@lsu.edu; Carver, Robert L.; Gibbons, John P. [Mary Bird Perkins Cancer Center, 4950 Essen Lane, Baton Rouge, Louisiana 70809-3482 and Department of Physics and Astronomy, Louisiana State University, 202 Nicholson Hall, Baton Rouge, Louisiana 70803-4001 (United States); Clarke, Taylor; Henderson, Alexander; Liang, Edison P. [Physics and Astronomy Department, Rice University, 6100 Main MS-61, Houston, Texas 77005-1827 (United States)

    2015-09-15

    Purpose: The purpose of this work was to adapt a lightweight, permanent magnet electron energy spectrometer for the measurement of energy spectra of therapeutic electron beams. Methods: An irradiation geometry and measurement technique were developed for an approximately 0.54-T, permanent dipole magnet spectrometer to produce suitable latent images on computed radiography (CR) phosphor strips. Dual-pinhole electron collimators created a 0.318-cm diameter, approximately parallel beam incident on the spectrometer and an appropriate dose rate at the image plane (CR strip location). X-ray background in the latent image, reduced by a 7.62-cm thick lead block between the pinhole collimators, was removed using a fitting technique. Theoretical energy-dependent detector response functions (DRFs) were used in an iterative technique to transform CR strip net mean dose profiles into energy spectra on central axis at the entrance to the spectrometer. These spectra were transformed to spectra at 95-cm source to collimator distance (SCD) by correcting for the energy dependence of electron scatter. The spectrometer was calibrated by comparing peak mean positions in the net mean dose profiles, initially to peak mean energies determined from the practical range of central-axis percent depth-dose (%DD) curves, and then to peak mean energies that accounted for how the collimation modified the energy spectra (recalibration). The utility of the spectrometer was demonstrated by measuring the energy spectra for the seven electron beams (7–20 MeV) of an Elekta Infinity radiotherapy accelerator. Results: Plots of DRF illustrated their dependence on energy and position in the imaging plane. Approximately 15 iterations solved for the energy spectra at the spectrometer entrance from the measured net mean dose profiles. Transforming those spectra into ones at 95-cm SCD increased the low energy tail of the spectra, while correspondingly decreasing the peaks and shifting them to slightly lower

  9. Permanent-magnet energy spectrometer for electron beams from radiotherapy accelerators.

    Science.gov (United States)

    McLaughlin, David J; Hogstrom, Kenneth R; Carver, Robert L; Gibbons, John P; Shikhaliev, Polad M; Matthews, Kenneth L; Clarke, Taylor; Henderson, Alexander; Liang, Edison P

    2015-09-01

    The purpose of this work was to adapt a lightweight, permanent magnet electron energy spectrometer for the measurement of energy spectra of therapeutic electron beams. An irradiation geometry and measurement technique were developed for an approximately 0.54-T, permanent dipole magnet spectrometer to produce suitable latent images on computed radiography (CR) phosphor strips. Dual-pinhole electron collimators created a 0.318-cm diameter, approximately parallel beam incident on the spectrometer and an appropriate dose rate at the image plane (CR strip location). X-ray background in the latent image, reduced by a 7.62-cm thick lead block between the pinhole collimators, was removed using a fitting technique. Theoretical energy-dependent detector response functions (DRFs) were used in an iterative technique to transform CR strip net mean dose profiles into energy spectra on central axis at the entrance to the spectrometer. These spectra were transformed to spectra at 95-cm source to collimator distance (SCD) by correcting for the energy dependence of electron scatter. The spectrometer was calibrated by comparing peak mean positions in the net mean dose profiles, initially to peak mean energies determined from the practical range of central-axis percent depth-dose (%DD) curves, and then to peak mean energies that accounted for how the collimation modified the energy spectra (recalibration). The utility of the spectrometer was demonstrated by measuring the energy spectra for the seven electron beams (7-20 MeV) of an Elekta Infinity radiotherapy accelerator. Plots of DRF illustrated their dependence on energy and position in the imaging plane. Approximately 15 iterations solved for the energy spectra at the spectrometer entrance from the measured net mean dose profiles. Transforming those spectra into ones at 95-cm SCD increased the low energy tail of the spectra, while correspondingly decreasing the peaks and shifting them to slightly lower energies. Energy calibration

  10. Study and realization of an electron linear accelerator. Dynamics of accelerated electrons

    International Nuclear Information System (INIS)

    Bernard, J.

    1966-12-01

    The theoretical characteristics of the electron linear accelerator are: 30 MeV for the energy W S and 250 mA for the peak current I c . The main utilization is the intense production of fast neutrons by the reactions (γ,n) and (γ,f) induced in a target of natural uranium by the accelerated electrons. In the first part of the thesis, relative to the study and the realization of the accelerator, a new equation of dispersion is established analytically when the guide is loaded with round-edged irises. The relation is compared with the equation established by CHU and Hansen, WALKINSHAW, KVASIL in the case of a guide loaded with flat-edged irises. The experimental and theoretical curves of dispersion are compared. The accuracy of every relation of dispersion is estimated. The second part of the thesis is relative to the theoretical study of the electrons dynamics in the guide; it allows the derivation of the parameters of the beam: dispersion of phase, energy, dispersion of energy and the relation W S = f (I c ). The results relative to the first experiments are given and compared with the theoretical expectations. (author) [fr

  11. Cost analysis of low energy electron accelerator for film curing

    International Nuclear Information System (INIS)

    Ochi, Masafumi

    2003-01-01

    Low energy electron accelerators are recognized as one of the advanced curing means of converting processes for films and papers. In the last three years the price of the accelerator equipment has been greatly reduced. The targeted application areas are mainly processes of curing inks, coatings, and adhesives to make packaging materials. The operating cost analyses were made for electron beam (EB) processes over the conventional ones without EB. Then three new proposals for cost reduction of EB processes are introduced. Also being developed are new EB chemistries such as coatings, laminating adhesives and inks. EB processes give instantaneous cure and EB chemistries are basically non solvent causing less VOC emission to the environment. These developments of both equipment and chemistries might have a potential to change conventional packaging film industries. (author)

  12. Collective accelerator for electron colliders

    Energy Technology Data Exchange (ETDEWEB)

    Briggs, R.J.

    1985-05-13

    A recent concept for collective acceleration and focusing of a high energy electron bunch is discussed, in the context of its possible applicability to large linear colliders in the TeV range. The scheme can be considered to be a member of the general class of two-beam accelerators, where a high current, low voltage beam produces the acceleration fields for a trailing high energy bunch.

  13. Collective accelerator for electron colliders

    International Nuclear Information System (INIS)

    Briggs, R.J.

    1985-01-01

    A recent concept for collective acceleration and focusing of a high energy electron bunch is discussed, in the context of its possible applicability to large linear colliders in the TeV range. The scheme can be considered to be a member of the general class of two-beam accelerators, where a high current, low voltage beam produces the acceleration fields for a trailing high energy bunch

  14. Electron accelerators: History, applications, and perspectives

    Science.gov (United States)

    Martins, M. N.; Silva, T. F.

    2014-02-01

    This paper will present an outlook on sources of radiation, focusing on electron accelerators. We will review advances that were important for the development of particle accelerators, concentrating on those that led to modern electron accelerators. Electron accelerators are multipurpose machines that deliver beams with energies spanning five orders of magnitude, and are used in applications that range from fundamental studies of particle interactions to cross-linking polymer chains in industrial plants. Each accelerator type presents specific characteristics that make it more suitable for certain applications. Our work will focus on radiation sources for medical applications, dominated by electron linacs (linear accelerators), and those used for research, field where electron rings dominate. We will outline the main technological advances that occurred in the past decades, which made possible the construction of machines fit for clinical environments. Their compactness, efficiency and reliability have been key to their acceptance in clinical applications. This outline will include advances that allowed for the construction of brighter synchrotron light sources, where the relevant beam characteristics are good optical quality and high beam current. The development of insertion devices will also be discussed, as well the development of Free Electron Lasers (FEL). We conclude the review with an outline of the new developments of electron accelerators and the expectations for Energy Recovery Linacs.

  15. Energy Limits of Electron Acceleration in the Plasma Sheet During Substorms: A Case Study with the Magnetospheric Multiscale (MMS) Mission

    Science.gov (United States)

    Turner, D. L.; Fennell, J. F.; Blake, J. B.; Clemmons, J. H.; Mauk, B. H.; Cohen, I. J.; Jaynes, A. N.; Craft, J. V.; Wilder, F. D.; Baker, D. N.; hide

    2016-01-01

    We present multipoint observations of earthward moving dipolarization fronts and energetic particle injections from NASAs Magnetospheric Multiscale mission with a focus on electron acceleration. From a case study during a substorm on 02 August 2015, we find that electrons are only accelerated over a finite energy range, from a lower energy threshold at approx. 7-9 keV up to an upper energy cutoff in the hundreds of keV range. At energies lower than the threshold energy, electron fluxes decrease, potentially due to precipitation by strong parallel electrostatic wavefields or initial sources in the lobes. Electrons at energies higher than the threshold are accelerated cumulatively by a series of impulsive magnetic dipolarization events. This case demonstrates how the upper energy cutoff increases, in this case from approx. 130 keV to >500 keV, with each depolarization/injection during sustained activity. We also present a simple model accounting for these energy limits that reveals that electron energization is dominated by betatron acceleration.

  16. Experience and development program for the I.V. Kurchatov Atomic Energy Institute electron linear accelerator

    International Nuclear Information System (INIS)

    Aref'ev, A.V.; Blokhov, M.V.; Gerasimov, V.F.

    1981-01-01

    A program of physical investigations and the corresponding requirements to accelerated beam parameters are discussed in brief. The state and working capacity of separate units and the accelerator as a whole for the 8-year operating period are analyzed. The aim and principal program points of linear electron accelerator modernization are defined. The program of accelerator modernization assumes: electron beam energy increase up to 100-120 MeV; mounting of three additional accelerating sections; clystron efficiency increase; development of a highly reliable modulator; stabilized power supply sources; a system of synchronous start-up; a focusing system; a beam separation system and etc [ru

  17. High Power Electron Accelerator Prototype

    CERN Document Server

    Tkachenko, Vadim; Cheskidov, Vladimir; Korobeynikov, G I; Kuznetsov, Gennady I; Lukin, A N; Makarov, Ivan; Ostreiko, Gennady; Panfilov, Alexander; Sidorov, Alexey; Tarnetsky, Vladimir V; Tiunov, Michael A

    2005-01-01

    In recent time the new powerful industrial electron accelerators appear on market. It caused the increased interest to radiation technologies using high energy X-rays due to their high penetration ability. However, because of low efficiency of X-ray conversion for electrons with energy below 5 MeV, the intensity of X-rays required for some industrial applications can be achieved only when the beam power exceeds 300 kW. The report describes a project of industrial electron accelerator ILU-12 for electron energy up to 5 MeV and beam power up to 300 kW specially designed for use in industrial applications. On the first stage of work we plan to use the existing generator designed for ILU-8 accelerator. It is realized on the GI-50A triode and provides the pulse power up to 1.5-2 MW and up to 20-30 kW of average power. In the report the basic concepts and a condition of the project for today are reflected.

  18. Powerful accelerators for bremsstrahlung and electron beams generation on the basis of inductive energy-storage elements

    Energy Technology Data Exchange (ETDEWEB)

    Diyankov, V S; Kovalev, V P; Kormilitsin, A I; Lavrentev, B N [All-Russian Research Institute of Technical Physics, Snezhinsk (Russian Federation)

    1997-12-31

    The report summarizes RFNC-VNIITF activities from 1963 till 1995, devoted to the development of pulsed electron accelerators on the basis of inductive energy storage with electroexplosive wires. These accelerators are called IGUR. The activities resulted in the development of a series of generators of powerful radiation being cheap and easy in manufacturing and servicing. The accelerators achieved the following maximum parameters: diode voltage up to 6 MV, diode current up to 80 kA, current of the extracted electron beam 30 kA, density of the extracted electron beam energy 500 J/cm{sup 2}, bremsstrahlung dose 250000 Rads, and bremsstrahlung dose rate 10{sup 13} Rads/sec. (author). 3 tabs., 5 figs., 7 refs.

  19. Powerful accelerators for bremsstrahlung and electron beams generation on the basis of inductive energy-storage elements

    International Nuclear Information System (INIS)

    Diyankov, V.S.; Kovalev, V.P.; Kormilitsin, A.I.; Lavrentev, B.N.

    1996-01-01

    The report summarizes RFNC-VNIITF activities from 1963 till 1995, devoted to the development of pulsed electron accelerators on the basis of inductive energy storage with electroexplosive wires. These accelerators are called IGUR. The activities resulted in the development of a series of generators of powerful radiation being cheap and easy in manufacturing and servicing. The accelerators achieved the following maximum parameters: diode voltage up to 6 MV, diode current up to 80 kA, current of the extracted electron beam 30 kA, density of the extracted electron beam energy 500 J/cm 2 , bremsstrahlung dose 250000 Rads, and bremsstrahlung dose rate 10 13 Rads/sec. (author). 3 tabs., 5 figs., 7 refs

  20. Control of electron injection and acceleration in laser-wakefield accelerators

    International Nuclear Information System (INIS)

    Guillaume, E.

    2015-01-01

    Laser-plasma accelerators provide a promising compact alternative to conventional accelerators. Plasma waves with extremely strong electric fields are generated when a high intensity laser is focused into an underdense gas target. Electrons that are trapped in these laser-driven plasma waves can be accelerated up to energies of a few GeVs. Despite their great potential, laser-wakefield accelerators face some issues, regarding notably the stability and reproducibility of the beam when electrons are injected in the accelerating structure. In this manuscript, different techniques of electron injection are presented and compared, notably injection in a sharp density gradient and ionization injection. It is shown that combining these two methods allows for the generation of stable and tunable electron beams. We have also studied a way to manipulate the electron bunch in the phase-space in order to accelerate the bunch beyond the dephasing limit. Such a technique was used with quasi-monoenergetic electron beams to enhance their energy. Moreover, the origin of the evolution of the angular momentum of electrons observed experimentally was investigated. Finally, we demonstrated experimentally a new method - the laser-plasma lens - to strongly reduce the divergence of the electron beam. This laser-plasma lens consists of a second gas jet placed at the exit of the accelerator. The laser pulse drives a wakefield in this second jet whose focusing forces take advantage to reduce the divergence of the trailing electron bunch. A simple analytical model describing the principle is presented, underlining the major importance of the second jet length, density and distance from the first jet. Experimental demonstration of the laser-plasma lens shows a divergence reduction by a factor of 2.6 for electrons up to 300 MeV, in accordance with the model predictions

  1. High energy gain electron beam acceleration by 100TW laser

    International Nuclear Information System (INIS)

    Kotaki, Hideyuki; Kando, Masaki; Kondo, Shuji; Hosokai, Tomonao; Kanazawa, Shuhei; Yokoyama, Takashi; Matoba, Toru; Nakajima, Kazuhisa

    2001-01-01

    A laser wakefield acceleration experiment using a 100TW laser is planed at JAERI-Kansai. High quality and short pulse electron beams are necessary to accelerate the electron beam by the laser. Electron beam - laser synchronization is also necessary. A microtron with a photocathode rf-gun was prepared as a high quality electron injector. The quantum efficiency (QE) of the photocathode of 2x10 -5 was obtained. A charge of 100pC from the microtron was measured. The emittance and pulse width of the electron beam was 6π mm-mrad and 10ps, respectively. In order to produce a short pulse electron beam, and to synchronize between the electron beam and the laser pulse, an inverse free electron laser (IFEL) is planned. One of problems of LWFA is the short acceleration length. In order to overcome the problem, a Z-pinch plasma waveguide will be prepared as a laser wakefield acceleration tube for 1 GeV acceleration. (author)

  2. Present state and problems of radiological protection monitoring for high energy electron accelerator facilities in SPring-8

    International Nuclear Information System (INIS)

    Miyamoto, Yukihiro; Harada, Yasunori; Ueda, Hisao

    1998-09-01

    The present state and problems of the radiological protection monitoring for the high-energy electron accelerator are summarized. In the radiological protection monitoring for SPring-8, a third generation synchrotron radiation facility, there are many problems specific to the high-energy electron accelerator. This report describes the monitoring technique of pulsed radiation, high-energy radiation and low-energy radiation, and their problems. The management of induced radioactivity and the effects of electro-magnetic noise to monitoring instruments are also discussed. (author)

  3. CAS - CERN Accelerator School: Free Electron Lasers and Energy Recovery Linacs

    CERN Document Server

    2018-01-01

    These proceedings collate lectures given at the course on Free Electron Lasers and Energy Recovery Linacs (FELsand ERLs), organised by the CERN Accelerator School (CAS). The course was held at the Hotel Scandic HamburgEmporio, Hamburg, Germany from 31 May to 10 June 2016, in collaboration with DESY. Following introductorylectures on radiation issues, the basic requirements on linear accelerators and ERLs are discussed. Undulators andthe process of seeding and lasing are then treated in some detail, followed by lectures on various beam dynamicsand controls issues.

  4. Electron energy and electron trajectories in an inverse free-electron laser accelerator based on a novel electrostatic wiggler

    Science.gov (United States)

    Nikrah, M.; Jafari, S.

    2016-06-01

    We expand here a theory of a high-gradient laser-excited electron accelerator based on an inverse free-electron laser (inverse-FEL), but with innovations in the structure and design. The electrostatic wiggler used in our scheme, namely termed the Paul wiggler, is generated by segmented cylindrical electrodes with applied oscillatory voltages {{V}\\text{osc}}(t) over {{90}\\circ} segments. The inverse-FEL interaction can be described by the equations that govern the electron motion in the combined fields of both the laser pulse and Paul wiggler field. A numerical study of electron energy and electron trajectories has been made using the fourth-order Runge-Kutta method. The results indicate that the electron attains a considerable energy at short distances in this device. It is found that if the electron has got sufficient suitable wiggler amplitude intensities, it can not only gain higher energy in longer distances, but also can retain it even after the passing of the laser pulse. In addition, the results reveal that the electron energy gains different peaks for different initial axial velocities, so that a suitable small initial axial velocity of e-beam produces substantially high energy gain. With regard to the transverse confinement of the electron beam in a Paul wiggler, there is no applied axial guide magnetic field in this device.

  5. DARMSTADT: Superconducting electron accelerator in operation

    International Nuclear Information System (INIS)

    Anon.

    1991-01-01

    In December, the S-DALINAC superconducting radiofrequency electron accelerator at the Nuclear Physics Institute of Darmstadt's Technische Hochschule was completed. This pioneer continuous-wave (c.w.) machine passed a major milestone several years ago when it accelerated its first low energy electron beam

  6. High energy particle accelerators as radiation Sources

    Energy Technology Data Exchange (ETDEWEB)

    Abdelaziz, M E [National Center for Nuclear Safety and Radiation Vontrol, Atomic Energy Authority, Cairo (Egypt)

    1997-12-31

    Small accelerators in the energy range of few million electron volts are usually used as radiation sources for various applications, like radiotherapy, food irradiation, radiation sterilization and in other industrial applications. High energy accelerators with energies reaching billions of electron volts also find wide field of applications as radiation sources. Synchrotrons with high energy range have unique features as radiation sources. This review presents a synopsis of cyclic accelerators with description of phase stability principle of high energy accelerators with emphasis on synchrotrons. Properties of synchrotron radiation are given together with their applications in basic and applied research. 13 figs.,1 tab.

  7. Coincidence set-up with a high duty-cycle, high energy electron accelerator

    International Nuclear Information System (INIS)

    Leconte, P.

    1981-01-01

    Important studies are now undertaken to develop continuous wave electron accelerators with energy ranging from 1 to 4 Gev. So very important effort must be now put on the development of the experimental set-up matching the performances expected from the electron beam. Major steps in the understanding of the nuclear systems will come from more and more exclusive experiments where well defined mechanisms will be selected

  8. Shielding considerations for an electron linear accelerator complex for high energy physics and photonics research

    International Nuclear Information System (INIS)

    Holmes, J.A.; Huntzinger, C.J.

    1987-01-01

    Radiation shielding considerations for a major high-energy physics and photonics research complex which comprise a 50 MeV electron linear accelerator injector, a 1.0 GeV electron linear accelerator and a 1.3 GeV storage ring are discussed. The facilities will be unique because of the close proximity of personnel to the accelerator beam lines, the need to adapt existing facilities and shielding materials and the application of strict ALARA dose guidelines while providing maximum access and flexibility during a phased construction program

  9. Low voltage electron beam accelerators

    International Nuclear Information System (INIS)

    Ochi, Masafumi

    2003-01-01

    Widely used electron accelerators in industries are the electron beams with acceleration voltage at 300 kV or less. The typical examples are shown on manufactures in Japan, equipment configuration, operation, determination of process parameters, and basic maintenance requirement of the electron beam processors. New electron beam processors with acceleration voltage around 100 kV were introduced maintaining the relatively high dose speed capability of around 10,000 kGy x mpm at production by ESI (Energy Science Inc. USA, Iwasaki Electric Group). The application field like printing and coating for packaging requires treating thickness of 30 micron or less. It does not require high voltage over 110 kV. Also recently developed is a miniature bulb type electron beam tube with energy less than 60 kV. The new application area for this new electron beam tube is being searched. The drive force of this technology to spread in the industries would be further development of new application, process and market as well as the price reduction of the equipment, upon which further acknowledgement and acceptance of the technology to societies and industries would entirely depend. (Y. Tanaka)

  10. Low voltage electron beam accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Ochi, Masafumi [Iwasaki Electric Co., Ltd., Tokyo (Japan)

    2003-02-01

    Widely used electron accelerators in industries are the electron beams with acceleration voltage at 300 kV or less. The typical examples are shown on manufactures in Japan, equipment configuration, operation, determination of process parameters, and basic maintenance requirement of the electron beam processors. New electron beam processors with acceleration voltage around 100 kV were introduced maintaining the relatively high dose speed capability of around 10,000 kGy x mpm at production by ESI (Energy Science Inc. USA, Iwasaki Electric Group). The application field like printing and coating for packaging requires treating thickness of 30 micron or less. It does not require high voltage over 110 kV. Also recently developed is a miniature bulb type electron beam tube with energy less than 60 kV. The new application area for this new electron beam tube is being searched. The drive force of this technology to spread in the industries would be further development of new application, process and market as well as the price reduction of the equipment, upon which further acknowledgement and acceptance of the technology to societies and industries would entirely depend. (Y. Tanaka)

  11. Technology and applications of electron accelerator

    International Nuclear Information System (INIS)

    Natsir, M.

    1998-01-01

    Technology of electron accelerator have been developed so fast in advanced countries. It was applied in the research and development (R and D) and comercially in various industries. The industries applying electron accelerator includes polymers industry, sterilization of medical tools, material surface modification, and environmental management. The radiation process using electron beam is an ionization radiation process. Two facilities of electron accelerator have been established in pilot scale at the Centre for the Application of Isotope and Radiation CAIR-BATAN, Jakarta, for the RandD of radiation process technology and in demonstrating the electron accelerator application in industry in Indonesia. The first has low energy specification of 300 keV, 50 mA, EPS-300 type and the second has medium energy specification of 2 MeV, 10 mA dynamitron model GJ-2 type. Both the electron accelerators have an electron penetration depth capability of 0.6 and 12 mm, respectively, for the double side irradiation in the materials with density of 1 g/cm 3 . They also highly capacity production and electron beam cross-section of 120 cm length and 10 cm width. The beam will go through the atmosphere for irradiation samples or industrial products. The radiation dose can be selected precisely by adjusting the electron beam current and conveyor speed. Both of these facilities were applied in many aspects RandD, for examples dosimetry, wood surface coating, cross-linking of polymer, heatshrincable tube, polymer grafting, plastic degradation, food preservation, sterilization and so on. Engineering factors of radiation design process and general observation of electron accelerator application in RandD for various industries in Indonesia are briefly discussed

  12. A permanent magnet electron beam spread system used for a low energy electron irradiation accelerator

    International Nuclear Information System (INIS)

    Huang Jiang; Xiong Yongqian; Chen Dezhi; Liu Kaifeng; Yang Jun; Li Dong; Yu Tiaoqin; Fan Mingwu; Yang Bo

    2014-01-01

    The development of irradiation processing industry brings about various types of irradiation objects and expands the irradiation requirements for better uniformity and larger areas. This paper proposes an innovative design of a permanent magnet electron beam spread system. By clarifying its operation principles, the author verifies the feasibility of its application in irradiation accelerators for industrial use with the examples of its application in electron accelerators with energy ranging from 300 keV to 1 MeV. Based on the finite element analyses of electromagnetic fields and the charged particle dynamics, the author also conducts a simulation of electron dynamics in magnetic field on a computer. The results indicate that compared with the traditional electron beam scanning system, this system boosts the advantages of a larger spread area, non-power supply, simple structure and low cost, etc., which means it is not only suitable for the irradiation of objects with the shape of tubes, strips and panels, but can also achieve a desirable irradiation performance on irregular constructed objects of large size. (authors)

  13. Study and realization of an electron linear accelerator. Dynamics of accelerated electrons; Etude et realisation d'un accelerateur lineaire d'electrons. Dynamique des electrons acceleres

    Energy Technology Data Exchange (ETDEWEB)

    Bernard, J [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1967-04-01

    The theoretical characteristics of the electron linear accelerator are: 30 MeV for the energy W{sub S} and 250 mA for the peak current I{sub c}. The main utilization is the intense production of fast neutrons by the reactions ({gamma},n) and ({gamma},f) induced in a target of natural uranium by the accelerated electrons. In the first part of the thesis, relative to the study and the realization of the accelerator, a new equation of dispersion is established analytically when the guide is loaded with round-edged irises. The relation is compared with the equation established by CHU and Hansen, WALKINSHAW, KVASIL in the case of a guide loaded with flat-edged irises. The experimental and theoretical curves of dispersion are compared. The accuracy of every relation of dispersion is estimated. The second part of the thesis is relative to the theoretical study of the electrons dynamics in the guide; it allows the derivation of the parameters of the beam: dispersion of phase, energy, dispersion of energy and the relation W{sub S} = f (I{sub c}). The results relative to the first experiments are given and compared with the theoretical expectations. (author) [French] Les caracteristiques nominales theoriques de l'accelerateur lineaire d'electrons sont: 30 MeV pour l'energie W{sub S} et 250 mA pour le courant de crete I{sub c}. L'utilisation principale envisagee est la production de neutrons rapides par les reactions ({gamma},n) et ({gamma},f) induites dans une cible d'uranium naturel par les electrons acceleres. Dans la premiere partie de la these relative a l'elude et a la realisation de l'accelerateur, une nouvelle equation de dispersion (ou equation aux frequences) est etablie analytiquement pour un guide charge par des iris a bord rond. Cette relation est comparee a celles etablies par CHU et HANSEN, WALKINSHAW, KVASIL dans le cas du guide charge par des iris a bord plat. On compare les courbes de dispersion theoriques et experimentales et on evalue la precision de

  14. Beam dosimetry in high-power electron accelerators

    International Nuclear Information System (INIS)

    Popov, V.N.; Zhitomirskii, B.M.; Ermakov, A.N.; Terebilin, A.V.; Stryukov, V.A.

    1987-01-01

    In order to evaluate beam utilization efficiency, measure the radiation yield, and determine the cost effectiveness of the new technologies, it is necessary to know the radiation power of the electron beam absorbed by the reacting medium. To measure the electron-beam power the authors designed, built, and tested a radiation detector combining a Faraday cylinder with a continuous-flow calorimeter. The construction of the detector is shown. The radiation detector was tested on a number of electron accelerators. The beam-power and mean-electron-energy measurement results for the LUE-8M accelerator with 8 MeV maximum electron energy are given

  15. Plasma production for electron acceleration by resonant plasma wave

    International Nuclear Information System (INIS)

    Anania, M.P.; Biagioni, A.; Chiadroni, E.; Cianchi, A.; Croia, M.; Curcio, A.; Di Giovenale, D.; Di Pirro, G.P.; Filippi, F.; Ghigo, A.; Lollo, V.; Pella, S.; Pompili, R.; Romeo, S.; Ferrario, M.

    2016-01-01

    Plasma wakefield acceleration is the most promising acceleration technique known nowadays, able to provide very high accelerating fields (10–100 GV/m), enabling acceleration of electrons to GeV energy in few centimeter. However, the quality of the electron bunches accelerated with this technique is still not comparable with that of conventional accelerators (large energy spread, low repetition rate, and large emittance); radiofrequency-based accelerators, in fact, are limited in accelerating field (10–100 MV/m) requiring therefore hundred of meters of distances to reach the GeV energies, but can provide very bright electron bunches. To combine high brightness electron bunches from conventional accelerators and high accelerating fields reachable with plasmas could be a good compromise allowing to further accelerate high brightness electron bunches coming from LINAC while preserving electron beam quality. Following the idea of plasma wave resonant excitation driven by a train of short bunches, we have started to study the requirements in terms of plasma for SPARC-LAB (Ferrario et al., 2013 [1]). In particular here we focus on hydrogen plasma discharge, and in particular on the theoretical and numerical estimates of the ionization process which are very useful to design the discharge circuit and to evaluate the current needed to be supplied to the gas in order to have full ionization. Eventually, the current supplied to the gas simulated will be compared to that measured experimentally.

  16. Plasma production for electron acceleration by resonant plasma wave

    Energy Technology Data Exchange (ETDEWEB)

    Anania, M.P., E-mail: maria.pia.anania@lnf.infn.it [INFN - LNF, via Enrico Fermi, 40, 00044 Frascati (Italy); Biagioni, A.; Chiadroni, E. [INFN - LNF, via Enrico Fermi, 40, 00044 Frascati (Italy); Cianchi, A. [University of Rome Tor Vergata - INFN, via della Ricerca Scientifica, 1, 00133 Roma (Italy); INFN, Via della Ricerca Scientifica, 1, 00133 Roma (Italy); Croia, M.; Curcio, A. [INFN - LNF, via Enrico Fermi, 40, 00044 Frascati (Italy); University of Rome La Sapienza, Piazzale Aldo Moro, 2, 00185 Roma (Italy); Di Giovenale, D.; Di Pirro, G.P. [INFN - LNF, via Enrico Fermi, 40, 00044 Frascati (Italy); Filippi, F. [University of Rome La Sapienza, Piazzale Aldo Moro, 2, 00185 Roma (Italy); Ghigo, A.; Lollo, V.; Pella, S.; Pompili, R. [INFN - LNF, via Enrico Fermi, 40, 00044 Frascati (Italy); Romeo, S. [INFN - LNF, via Enrico Fermi, 40, 00044 Frascati (Italy); University of Rome La Sapienza, Piazzale Aldo Moro, 2, 00185 Roma (Italy); Ferrario, M. [INFN - LNF, via Enrico Fermi, 40, 00044 Frascati (Italy)

    2016-09-01

    Plasma wakefield acceleration is the most promising acceleration technique known nowadays, able to provide very high accelerating fields (10–100 GV/m), enabling acceleration of electrons to GeV energy in few centimeter. However, the quality of the electron bunches accelerated with this technique is still not comparable with that of conventional accelerators (large energy spread, low repetition rate, and large emittance); radiofrequency-based accelerators, in fact, are limited in accelerating field (10–100 MV/m) requiring therefore hundred of meters of distances to reach the GeV energies, but can provide very bright electron bunches. To combine high brightness electron bunches from conventional accelerators and high accelerating fields reachable with plasmas could be a good compromise allowing to further accelerate high brightness electron bunches coming from LINAC while preserving electron beam quality. Following the idea of plasma wave resonant excitation driven by a train of short bunches, we have started to study the requirements in terms of plasma for SPARC-LAB (Ferrario et al., 2013 [1]). In particular here we focus on hydrogen plasma discharge, and in particular on the theoretical and numerical estimates of the ionization process which are very useful to design the discharge circuit and to evaluate the current needed to be supplied to the gas in order to have full ionization. Eventually, the current supplied to the gas simulated will be compared to that measured experimentally.

  17. Evidence for acceleration of outer zone electrons to relativistic energies by whistler mode chorus

    Directory of Open Access Journals (Sweden)

    N. P. Meredith

    2002-07-01

    Full Text Available We use plasma wave and electron data from the Combined Release and Radiation Effects Satellite (CRRES to investigate the viability of a local stochastic electron acceleration mechanism to relativistic energies driven by gyroresonant interactions with whistler mode chorus. In particular, we examine the temporal evolution of the spectral response of the electrons and the waves during the 9 October 1990 geomagnetic storm. The observed hardening of the electron energy spectra over about 3 days in the recovery phase is coincident with prolonged substorm activity, as monitored by the AE index and enhanced levels of whistler mode chorus waves. The observed spectral hardening is observed to take place over a range of energies appropriate to the resonant energies associated with Doppler-shifted cyclotron resonance, as supported by the construction of realistic resonance curves and resonant diffusion surfaces. Furthermore, we show that the observed spectral hardening is not consistent with energy-independent radial diffusion models. These results provide strong circumstantial evidence for a local stochastic acceleration mechanism, involving the energisation of a seed population of electrons with energies of the order of a few hundred keV to relativistic energies, driven by wave-particle interactions involving whistler mode chorus. The results suggest that this mechanism contributes to the reformation of the relativistic outer zone population during geomagnetic storms, and is most effective when the recovery phase is characterised by prolonged substorm activity. An additional significant result of this paper is that we demonstrate that the lower energy part of the storm-time electron distribution is in steady-state balance, in accordance with the Kennel and Petschek (1966 theory of limited stably-trapped particle fluxes.Key words. Magnetospheric physics (storms and substorms, energetic particles, trapped – Space plasma physics (wave-particle interactions

  18. Multibeam electron-ion accelerator with the energy of up to 1.5 MeV/charge

    International Nuclear Information System (INIS)

    Baranov, I.A.; Devyatko, N.N.; Obnorskij, V.V.; Trofimenko, S.M.; Shilov, V.P.; Ehjsmont, V.P.; Auslender, V.L.; Lazarev, V.N.; Panfilov, A.D.; Polyakov, V.A.

    1979-01-01

    Basic design peculiarities and parameters of multi-beam pulse linear accelerator for using as ion synchrotron injector, and simultaneously, as electron accelerator for radiation investigations are given. Cylindrical steel container, inside of which a coaxial resonator with a drift tube is placed, is the basis of the accelerator. Maximum energy of protons amounts to 1.5 MeV. Beam intensities of accelerated nucleus from carbon to argon are in the range of 10 11 -10 10 particles, accordingly. Main parameters of accelerated particle beam are the following: the energy - 0.2-1.3 MeV, m - 1current A,0m- 1 mean power W,0-12 kW- 1 beam diameter cm. The accelerator is equipped with a system of quasi-circular scanning for homogeneous irradiation of object surfaces [ru

  19. Super High Energy Colliding Beam Accelerators

    International Nuclear Information System (INIS)

    Abdelaziz, M.E.

    2009-01-01

    This lecture presents a review of cyclic accelerators and their energy limitations. A description is given of the phase stability principle and evolution of the synchrotron, an accelerator without energy limitation. Then the concept of colliding beams emerged to yield doubling of the beam energy as in the Tevatron 2 trillion electron volts (TeV) proton collider at Fermilab and the Large Hadron Collider (LHC) which is now planned as a 14-TeV machine in the 27 kilometer tunnel of the Large Electron Positron (LEP) collider at CERN. Then presentation is given of the Superconducting Supercollider (SSC), a giant accelerator complex with energy 40-TeV in a tunnel 87 kilometers in circumference under the country surrounding Waxahachie in Texas, U.S.A. These superhigh energy accelerators are intended to smash protons against protons at energy sufficient to reveal the nature of matter and to consolidate the prevailing general theory of elementary particle.

  20. Acceleration of Electrons in a Diffraction Dominated IFEL

    CERN Document Server

    Musumeci, Pietro; Pellegrini, Claudio; Ralph, J; Rosenzweig, J B; Sung, C; Tochitsky, Sergei Ya; Travish, Gil

    2004-01-01

    We report on the observation of energy gain in excess of 20 MeV at the Inverse Free Electron Laser Accelerator experiment at the Neptune Laboratory at UCLA. A 14.5 MeV electron beam is injected ina 50 cm long undulator strongly tapered both in period and field amplitude. A CO2 10 μ m laser with power >300 GW is used as the IFEL driver. The Rayleigh range of the laser (1.8cm) is shorter than the undulator length so that the interaction is diffraction dominated. Few per cent of the injected particles are trapped in stable accelerating buckets and electrons with energies up to 35 MeV are detected on the magnetic spectrometers. Experimental results on the scaling of the accelerator characteristics versus input parameters like injection energy, laser focus position and laser power are discussed. Three dimensional simulations are in good agreement with the electron energy spectrums observed in the experiment and indicate that substantial energy exchange between laser and electron beam only occurs in the firs...

  1. Wide angle spectrometers for intermadiate energy electron accelerators

    International Nuclear Information System (INIS)

    Leconte, P.

    1982-10-01

    It is shown that improvements of the detector acceptances (in solid angle and momentum bite) is as important as increased duty cycle for coincidence experiments. To have a maximum efficiency and thus to reduce the cost of experiments, it is imperative to develop maximum solid angle systems. This implies an axial symmetry with respect to the incoming beam. At Saclay, we have investigated some of the properties of specific detectors covering up to 90% of 4π steradians for a high energy, 100% duty cycle electron accelerator. The techniques of wide angle spectrometers have already been explored on a large scale in high energy physics. However, in the case of charged particles, such detectors, compared to classical iron dipole spectrometers, present a smaller resolving power and a rather low background rejection. The choice of which of these two solutions is to be used depends on the conditions of the specific experiment

  2. Dynamics of electron acceleration in laser-driven wakefields. Acceleration limits and asymmetric plasma waves

    Energy Technology Data Exchange (ETDEWEB)

    Popp, Antonia

    2011-12-16

    The experiments presented in this thesis study several aspects of electron acceleration in a laser-driven plasma wave. High-intensity lasers can efficiently drive a plasma wave that sustains electric fields on the order of 100 GV/m. Electrons that are trapped in this plasma wave can be accelerated to GeV-scale energies. As the accelerating fields in this scheme are 3-4 orders of magnitude higher than in conventional radio-frequency accelerators, the necessary acceleration distance can be reduced by the same factor, turning laser-wakefield acceleration (LWFA) into a promising compact, and potentially cheaper, alternative. However, laser-accelerated electron bunches have not yet reached the parameter standards of conventional accelerators. This work will help to gain better insight into the acceleration process and to optimize the electron bunch properties. The 25 fs, 1.8 J-pulses of the ATLAS laser at the Max-Planck-Institute of Quantum Optics were focused into a steady-state flow gas cell. This very reproducible and turbulence-free gas target allows for stable acceleration of electron bunches. Thus the sensitivity of electron parameters to subtle changes of the experimental setup could be determined with meaningful statistics. At optimized experimental parameters, electron bunches of {approx}50 pC total charge were accelerated to energies up to 450 MeV with a divergence of {approx}2 mrad FWHM. As, in a new design of the gas cell, its length can be varied from 2 to 14 mm, the electron bunch energy could be evaluated after different acceleration distances, at two different electron densities. From this evolution important acceleration parameters could be extracted. At an electron density of 6.43. 10{sup 18} cm{sup -3} the maximum electric field strength in the plasma wave was determined to be {approx}160 GV/m. The length after which the relativistic electrons outrun the accelerating phase of the electric field and are decelerated again, the so-called dephasing length

  3. Dynamics of electron acceleration in laser-driven wakefields. Acceleration limits and asymmetric plasma waves

    International Nuclear Information System (INIS)

    Popp, Antonia

    2011-01-01

    The experiments presented in this thesis study several aspects of electron acceleration in a laser-driven plasma wave. High-intensity lasers can efficiently drive a plasma wave that sustains electric fields on the order of 100 GV/m. Electrons that are trapped in this plasma wave can be accelerated to GeV-scale energies. As the accelerating fields in this scheme are 3-4 orders of magnitude higher than in conventional radio-frequency accelerators, the necessary acceleration distance can be reduced by the same factor, turning laser-wakefield acceleration (LWFA) into a promising compact, and potentially cheaper, alternative. However, laser-accelerated electron bunches have not yet reached the parameter standards of conventional accelerators. This work will help to gain better insight into the acceleration process and to optimize the electron bunch properties. The 25 fs, 1.8 J-pulses of the ATLAS laser at the Max-Planck-Institute of Quantum Optics were focused into a steady-state flow gas cell. This very reproducible and turbulence-free gas target allows for stable acceleration of electron bunches. Thus the sensitivity of electron parameters to subtle changes of the experimental setup could be determined with meaningful statistics. At optimized experimental parameters, electron bunches of ∼50 pC total charge were accelerated to energies up to 450 MeV with a divergence of ∼2 mrad FWHM. As, in a new design of the gas cell, its length can be varied from 2 to 14 mm, the electron bunch energy could be evaluated after different acceleration distances, at two different electron densities. From this evolution important acceleration parameters could be extracted. At an electron density of 6.43. 10 18 cm -3 the maximum electric field strength in the plasma wave was determined to be ∼160 GV/m. The length after which the relativistic electrons outrun the accelerating phase of the electric field and are decelerated again, the so-called dephasing length, was found to be 4.9 mm

  4. The formation of kappa-distribution accelerated electron populations in solar flares

    Energy Technology Data Exchange (ETDEWEB)

    Bian, Nicolas H.; Stackhouse, Duncan J.; Kontar, Eduard P. [School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ (United Kingdom); Emslie, A. Gordon, E-mail: n.bian@physics.gla.ac.uk, E-mail: d.stackhouse.1@research.gla.ac.uk, E-mail: eduard@astro.gla.ac.uk, E-mail: emslieg@wku.edu [Department of Physics and Astronomy, Western Kentucky University, Bowling Green, KY 42101 (United States)

    2014-12-01

    Driven by recent RHESSI observations of confined loop-top hard X-ray sources in solar flares, we consider stochastic acceleration of electrons in the presence of Coulomb collisions. If electron escape from the acceleration region can be neglected, the electron distribution function is determined by a balance between diffusive acceleration and collisions. Such a scenario admits a stationary solution for the electron distribution function that takes the form of a kappa distribution. We show that the evolution toward this kappa distribution involves a 'wave front' propagating forward in velocity space, so that electrons of higher energy are accelerated later; the acceleration timescales with energy according to τ{sub acc} ∼ E {sup 3/2}. At sufficiently high energies escape from the finite-length acceleration region will eventually dominate. For such energies, the electron velocity distribution function is obtained by solving a time-dependent Fokker-Planck equation in the 'leaky-box' approximation. Solutions are obtained in the limit of a small escape rate from an acceleration region that can effectively be considered a thick target.

  5. Critical analysis of industrial electron accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Korenev, S. E-mail: sergey_korenev@steris.com

    2004-10-01

    The critical analysis of electron linacs for industrial applications (degradation of PTFE, curing of composites, modification of materials, sterilization and others) is considered in this report. Main physical requirements for industrial electron accelerators consist in the variations of beam parameters, such as kinetic energy and beam power. Questions for regulation of these beam parameters are considered. The level of absorbed dose in the irradiated product and throughput determines the main parameters of electron accelerator. The type of ideal electron linac for industrial applications is discussed.

  6. Critical analysis of industrial electron accelerators

    Science.gov (United States)

    Korenev, S.

    2004-09-01

    The critical analysis of electron linacs for industrial applications (degradation of PTFE, curing of composites, modification of materials, sterlization and others) is considered in this report. Main physical requirements for industrial electron accelerators consist in the variations of beam parameters, such as kinetic energy and beam power. Questions for regulation of these beam parameters are considered. The level of absorbed dose in the irradiated product and throughput determines the main parameters of electron accelerator. The type of ideal electron linac for industrial applications is discussed.

  7. Critical analysis of industrial electron accelerators

    International Nuclear Information System (INIS)

    Korenev, S.

    2004-01-01

    The critical analysis of electron linacs for industrial applications (degradation of PTFE, curing of composites, modification of materials, sterilization and others) is considered in this report. Main physical requirements for industrial electron accelerators consist in the variations of beam parameters, such as kinetic energy and beam power. Questions for regulation of these beam parameters are considered. The level of absorbed dose in the irradiated product and throughput determines the main parameters of electron accelerator. The type of ideal electron linac for industrial applications is discussed

  8. Degradation of carrageenan by low energy electron accelerator

    International Nuclear Information System (INIS)

    Relleve, L.; Aranilla, C.; Abad, L.; Dela Rosa, A.; Nagasawa, Naotsugu; Yagi, Toshiaki; Kume, Tamikazu; Yoshii, Fumio

    2004-01-01

    Degradation of κ-carrageenan using vessel-type low energy electron accelerator was investigated. Carrageenan with different molecular weights were obtained from irradiation of high molecular weight (HMW) and low molecular weight (LMW) κ-carrageenan. Other results presented were obtained from degradation studies of carrageenan by gamma rays. The decrease in molecular weight was accompanied by partial desulfation. From comparison of radiation degradation yield (Gd), it was found that the susceptibility to radiation of the three types of carrageenans in aqueous/gel forms follows the order of λ->ι->>κ- and could have been influenced by their conformational state. κ-carrageenan with molecular weight of ca. 10,000 showed strong growth promotion effect for potato in tissue culture. (author)

  9. Secondary electrons monitor for continuous electron energy measurements in UHF linac

    International Nuclear Information System (INIS)

    Zimek, Zbigniew; Bulka, Sylwester; Mirkowski, Jacek; Roman, Karol

    2001-01-01

    Continuous energy measurements have now became obligatory in accelerator facilities devoted to radiation sterilization process. This is one of several accelerator parameters like dose rate, beam current, bean scan parameters, conveyer speed which must be recorded as it is a required condition of accelerator validation procedure. Electron energy measurements are rather simple in direct DC accelerator, where the applied DC voltage is directly related to electron energy. High frequency linacs are not offering such opportunity in electron energy measurements. The analyzing electromagnet is applied in some accelerators but that method can be used only in off line mode before or after irradiation process. The typical solution is to apply the non direct method related to control and measurements certain accelerator parameters like beam current and microwave energy pulse power. The continuous evaluation of electron energy can be performed on the base of calculation and result comparison with calibration curve

  10. The electron stretcher accelerator ELSA

    International Nuclear Information System (INIS)

    Husmann, D.

    1989-01-01

    The electron stretcher accelerator, ELSA, provides unpolarized and polarized electron beams at energies between 0.5 and 3.5 GeV at high duty factor up to 99%. ELSA partly can serve also as a synchrotron radiation source in the vacuum ultra violet and X-ray region. ELSA is a circular accelerator of 165 m circumference. The Bonn 2.5 GeV Electron Synchrotron, which came into operation in 1967, is used as injector. To achieve the above-mentioned features, ELSA is operated in three different modes. 'Stretcher mode' is used at energies between 0.5 and 2.0 GeV. For a beam energy above 2.0 GeV, ELSA is operated in the 'post acceleration mode'. Where it is operated as a dedicated 'synchrotron radiation source', electrons are accumulated up to a limit of about 50 mA at 3.5 GeV. Dipole fields to obtain a closed orbit and quadrupole fields to get beam focusing are realized with help of two kinds of magnets, namely dipoles and quadrupoles. This structure provides radiation damping of the horizontal betatron oscillation needed for bean storage. It also allows a wade range variation of the optical working point of the machine. The ring contains 12 sextupoles, in addition to 32 quadrupoles and 24 dipoles, for correction of the optics and for extraction purposes. (N.K.)

  11. Acceleration of polarized electrons in the Bonn electron-accelerator facility ELSA; Beschleunigung polarisierter Elektronen in der Bonner Elektronen-Beschleunigeranlage ELSA

    Energy Technology Data Exchange (ETDEWEB)

    Hoffmann, M.

    2001-12-01

    The future medium energy physics program at the electron stretcher accelerator ELSA of Bonn University mainly relies on experiments using polarized electrons in the energy range from 1 to 3.2 GeV. To prevent depolarization during acceleration in the circular accelerators several depolarizing resonances have to be corrected for. Intrinsic resonances are compensated using two pulsed betatron tune jump quadrupoles. The influence of imperfection resonances is successfully reduced applying a dynamic closed orbit correction in combination with an empirical harmonic correction on the energy ramp. Both types of resonances and the correction techniques have been studied in detail. The imperfection resonances were used to calibrate the energy of the stretcher ring with high accuracy. A new technique to extract the beam with horizontal oriented polarization was sucessfully installed. For all energies a polarized electron beam with more than 50% polarization can now be supplied to the experiments at ELSA, which is demonstrated by measurements using a Moeller polarimeter installed in the external beamline. (orig.)

  12. Industrial applications of electron accelerators

    International Nuclear Information System (INIS)

    Singh, A.

    1994-01-01

    The interaction of high-energy radiation with organic systems produces very reactive, short-lived, ionic and free-radical species. The chemical changes brought about by these species are very useful in several systems, and are the basis of the growth of the electron processing industry. Some typical areas of the industrial use of electron accelerators are crosslinking wire and cable insulation, manufacturing heat shrink plastic items, curing coatings, and partially curing rubber products. Electron accelerators are also being considered in other areas such as sewage treatment, sterilizing medical disposables, and food irradiation. An emerging application of industrial electron accelerators is the production of advanced composites for the aerospace and other industries. Traditionally, the carbon-, aramid- and glass-fibre-reinforced composites with epoxy matrices are produced by thermal curing. However, equivalent composites with acrylated-epoxy matrices can be made by electron curing. Cost estimates suggest that electron curing could be more economical than thermal curing. Food irradiation has traditionally been an application for 60 Co γ-radiation. With the increasing demand for food irradiation in various countries, it may become necessary to use electron accelerators for this purpose. Since the dose rate during gamma and electron irradiation are generally very different, a review of the relevant work on the effect of dose rates has been done. This paper presents an overview of the industrial applications of electron accelerator for radiation processing, emphasises the electron curing of advanced composites and, briefly reviews the dose-rate effects in radiation processing of advanced composites and food irradiation. (author). 84 refs., 8 tabs

  13. Inverse free-electron laser accelerator development

    International Nuclear Information System (INIS)

    Fisher, A.; Gallardo, J.; Steenbergen, A. van; Sandweiss, J.; Fang, J.M.

    1994-06-01

    The study of the Inverse Free-Electron Laser, as a potential mode of electron acceleration, has been pursued at Brookhaven National Laboratory for a number of years. More recent studies focused on the development of a low energy (few GeV), high gradient, multistage linear accelerator. The authors are presently designing a short accelerator module which will make use of the 50 MeV linac beam and high power (2 x 10 11 W) CO 2 laser beam of the Accelerator Test Facility (ATF) at the Center for Accelerator Physics (CAP), Brookhaven National Laboratory. These elements will be used in conjunction with a fast excitation (300 μsec pulse duration) variable period wiggler, to carry out an accelerator demonstration stage experiment

  14. Electron Acceleration in Supernovae and Millimeter Perspectives

    Directory of Open Access Journals (Sweden)

    Keiichi Maeda

    2014-12-01

    Full Text Available Supernovae launch a strong shock wave by the interaction of the expanding ejecta and surrounding circumstellar matter (CSM. At the shock, electrons are accelerated to relativistic speed, creating observed synchrotron emissions in radio wavelengths. In this paper, I suggest that SNe (i.e., < 1 year since the explosion provide a unique site to study the electron acceleration mechanism. I argue that the eciency of the acceleration at the young SN shock is much lower than conventionally assumed, and that the electrons emitting in the cm wavelengths are not fully in the Diffusive Shock Acceleration (DSA regime. Thus radio emissions from young SNe record information on the yet-unresolved 'injection' mechanism. I also present perspectives of millimeter (mm observations of SNe - this will provide opportunities to uniquely determine the shock physics and the acceleration efficiency, to test the non-linear DSA mechanism and provide a characteristic electron energy scale with which the DSA start dominating the electron acceleration.

  15. Probing electron acceleration and x-ray emission in laser-plasma accelerators

    International Nuclear Information System (INIS)

    Thaury, C.; Ta Phuoc, K.; Corde, S.; Brijesh, P.; Lambert, G.; Malka, V.; Mangles, S. P. D.; Bloom, M. S.; Kneip, S.

    2013-01-01

    While laser-plasma accelerators have demonstrated a strong potential in the acceleration of electrons up to giga-electronvolt energies, few experimental tools for studying the acceleration physics have been developed. In this paper, we demonstrate a method for probing the acceleration process. A second laser beam, propagating perpendicular to the main beam, is focused on the gas jet few nanosecond before the main beam creates the accelerating plasma wave. This second beam is intense enough to ionize the gas and form a density depletion, which will locally inhibit the acceleration. The position of the density depletion is scanned along the interaction length to probe the electron injection and acceleration, and the betatron X-ray emission. To illustrate the potential of the method, the variation of the injection position with the plasma density is studied

  16. High power electron accelerators for flue gas treatment

    International Nuclear Information System (INIS)

    Zimek, Z.

    2011-01-01

    Flue gas treatment process based on electron beam application for SO 2 and NO x removal was successfully demonstrated in number of laboratories, pilot plants and industrial demonstration facilities. The industrial scale application of an electron beam process for flue gas treatment requires accelerators modules with a beam power 100-500 kW and electron energy range 0.8-1.5 MeV. The most important accelerator parameters for successful flue gas radiation technology implementation are related to accelerator reliability/availability, electrical efficiency and accelerator price. Experience gained in high power accelerators exploitation in flue gas treatment industrial demonstration facility was described and high power accelerator constructions have been reviewed. (author)

  17. Secondary electron emission from plasma processed accelerating cavity grade niobium

    Science.gov (United States)

    Basovic, Milos

    Advances in the particle accelerator technology have enabled numerous fundamental discoveries in 20th century physics. Extensive interdisciplinary research has always supported further development of accelerator technology in efforts of reaching each new energy frontier. Accelerating cavities, which are used to transfer energy to accelerated charged particles, have been one of the main focuses of research and development in the particle accelerator field. Over the last fifty years, in the race to break energy barriers, there has been constant improvement of the maximum stable accelerating field achieved in accelerating cavities. Every increase in the maximum attainable accelerating fields allowed for higher energy upgrades of existing accelerators and more compact designs of new accelerators. Each new and improved technology was faced with ever emerging limiting factors. With the standard high accelerating gradients of more than 25 MV/m, free electrons inside the cavities get accelerated by the field, gaining enough energy to produce more electrons in their interactions with the walls of the cavity. The electron production is exponential and the electron energy transfer to the walls of a cavity can trigger detrimental processes, limiting the performance of the cavity. The root cause of the free electron number gain is a phenomenon called Secondary Electron Emission (SEE). Even though the phenomenon has been known and studied over a century, there are still no effective means of controlling it. The ratio between the electrons emitted from the surface and the impacting electrons is defined as the Secondary Electron Yield (SEY). A SEY ratio larger than 1 designates an increase in the total number of electrons. In the design of accelerator cavities, the goal is to reduce the SEY to be as low as possible using any form of surface manipulation. In this dissertation, an experimental setup was developed and used to study the SEY of various sample surfaces that were treated

  18. Secondary Electron Emission from Plasma Processed Accelerating Cavity Grade Niobium

    Energy Technology Data Exchange (ETDEWEB)

    Basovic, Milos [Old Dominion Univ., Norfolk, VA (United States)

    2016-05-01

    Advances in the particle accelerator technology have enabled numerous fundamental discoveries in 20th century physics. Extensive interdisciplinary research has always supported further development of accelerator technology in efforts of reaching each new energy frontier. Accelerating cavities, which are used to transfer energy to accelerated charged particles, have been one of the main focuses of research and development in the particle accelerator field. Over the last fifty years, in the race to break energy barriers, there has been constant improvement of the maximum stable accelerating field achieved in accelerating cavities. Every increase in the maximum attainable accelerating fields allowed for higher energy upgrades of existing accelerators and more compact designs of new accelerators. Each new and improved technology was faced with ever emerging limiting factors. With the standard high accelerating gradients of more than 25 MV/m, free electrons inside the cavities get accelerated by the field, gaining enough energy to produce more electrons in their interactions with the walls of the cavity. The electron production is exponential and the electron energy transfer to the walls of a cavity can trigger detrimental processes, limiting the performance of the cavity. The root cause of the free electron number gain is a phenomenon called Secondary Electron Emission (SEE). Even though the phenomenon has been known and studied over a century, there are still no effective means of controlling it. The ratio between the electrons emitted from the surface and the impacting electrons is defined as the Secondary Electron Yield (SEY). A SEY ratio larger than 1 designates an increase in the total number of electrons. In the design of accelerator cavities, the goal is to reduce the SEY to be as low as possible using any form of surface manipulation. In this dissertation, an experimental setup was developed and used to study the SEY of various sample surfaces that were treated

  19. Calculating the radiation characteristics of accelerated electrons in laser-plasma interactions

    International Nuclear Information System (INIS)

    Li, X. F.; Yu, Q.; Qu, J. F.; Kong, Q.; Gu, Y. J.; Ma, Y. Y.; Kawata, S.

    2016-01-01

    In this paper, we studied the characteristics of radiation emitted by electrons accelerated in a laser–plasma interaction by using the Lienard–Wiechert field. In the interaction of a laser pulse with a underdense plasma, electrons are accelerated by two mechanisms: direct laser acceleration (DLA) and laser wakefield acceleration (LWFA). At the beginning of the process, the DLA electrons emit most of the radiation, and the DLA electrons emit a much higher peak photon energy than the LWFA electrons. As the laser–plasma interaction progresses, the LWFA electrons become the major radiation emitter; however, even at this stage, the contribution from DLA electrons is significant, especially to the peak photon energy.

  20. Electron linear accelerator system for natural rubber vulcanization

    Science.gov (United States)

    Rimjaem, S.; Kongmon, E.; Rhodes, M. W.; Saisut, J.; Thongbai, C.

    2017-09-01

    Development of an electron accelerator system, beam diagnostic instruments, an irradiation apparatus and electron beam processing methodology for natural rubber vulcanization is underway at the Plasma and Beam Physics Research Facility, Chiang Mai University, Thailand. The project is carried out with the aims to improve the qualities of natural rubber products. The system consists of a DC thermionic electron gun, 5-cell standing-wave radio-frequency (RF) linear accelerator (linac) with side-coupling cavities and an electron beam irradiation apparatus. This system is used to produce electron beams with an adjustable energy between 0.5 and 4 MeV and a pulse current of 10-100 mA at a pulse repetition rate of 20-400 Hz. An average absorbed dose between 160 and 640 Gy is expected to be archived for 4 MeV electron beam when the accelerator is operated at 400 Hz. The research activities focus firstly on assembling of the accelerator system, study on accelerator properties and electron beam dynamic simulations. The resonant frequency of the RF linac in π/2 operating mode is 2996.82 MHz for the operating temperature of 35 °C. The beam dynamic simulations were conducted by using the code ASTRA. Simulation results suggest that electron beams with an average energy of 4.002 MeV can be obtained when the linac accelerating gradient is 41.7 MV/m. The rms transverse beam size and normalized rms transverse emittance at the linac exit are 0.91 mm and 10.48 π mm·mrad, respectively. This information can then be used as the input data for Monte Carlo simulations to estimate the electron beam penetration depth and dose distribution in the natural rubber latex. The study results from this research will be used to define optimal conditions for natural rubber vulcanization with different electron beam energies and doses. This is very useful for development of future practical industrial accelerator units.

  1. Technology and application of two sets of industrial electron accelerators

    International Nuclear Information System (INIS)

    Hua Degen

    2000-01-01

    The radiation industry in China Academy of Engineering Physics (CAEP) has had a big scale, and the two sets of industrial electron accelerators play important roles. The Electron Processing System (E.P.S), which was introduced in 1987, is a powerful electron accelerator. And the 10 MeV Accelerator, which is a traveling wave linear electron accelerator, has the higher electron energy. Both of the stes are equipped the driving devices under the beam, and has made a considerable economic results. This article describes the technology and application of the two electron accelerators. (author)

  2. The electron beam characteristics of energies up to 20 MeV and comparison of electron parameters of linear accelerators

    International Nuclear Information System (INIS)

    Awada, M.; Elleithy, M.A.; ElWihady, G.F.; Mostafa, K.A.

    2005-01-01

    The electron beams characteristics studded for the energies 4-20 MeV of Varian 23 EX ,experimental results are presented and compared with the published data. The CADD curves are measured for all energies and carried out the PDD of different applicator sizes ,that compared with the PDD of in the BJR. The quality beam parameters are determined from the CADD curves and calculated the yielded parameters of the corresponding electron energies which compared with the published data of other accelerators and theoretical Monte-Carlo calculation. The beam profiles are measured at different depths to construct the isodose distribution

  3. Near-GeV-energy laser-wakefield acceleration of self-injected electrons in a centimeter-scale plasma channel

    International Nuclear Information System (INIS)

    Tsung, F.S.; Narang, Ritesh; Joshi, C.; Mori, W. B.; Fonseca, R. A.; Silva, L.O.

    2004-01-01

    The first three-dimensional, particle-in-cell (PIC) simulations of laser-wakefield acceleration of self-injected electrons in a 0.84 cm long plasma channel are reported. The frequency evolution of the initially 50 fs (FWHM) long laser pulse by photon interaction with the wake followed by plasma dispersion enhances the wake which eventually leads to self-injection of electrons from the channel wall. This first bunch of electrons remains spatially highly localized. Its phase space rotation due to slippage with respect to the wake leads to a monoenergetic bunch of electrons with a central energy of 0.26 GeV after 0.55 cm propagation. At later times, spatial bunching of the laser enhances the acceleration of a second bunch of electrons to energies up to 0.84 GeV before the laser pulse intensity is significantly reduced

  4. Industrial applications of electron accelerators

    CERN Document Server

    Cleland, M R

    2006-01-01

    This paper addresses the industrial applications of electron accelerators for modifying the physical, chemical or biological properties of materials and commercial products by treatment with ionizing radiation. Many beneficial effects can be obtained with these methods, which are known as radiation processing. The earliest practical applications occurred during the 1950s, and the business of radiation processing has been expanding since that time. The most prevalent applications are the modification of many different plastic and rubber products and the sterilization of single-use medical devices. Emerging applications are the pasteurization and preservation of foods and the treatment of toxic industrial wastes. Industrial accelerators can now provide electron energies greater than 10 MeV and average beam powers as high as 700 kW. The availability of high-energy, high-power electron beams is stimulating interest in the use of X-rays (bremsstrahlung) as an alternative to gamma rays from radioactive nuclides.

  5. PIC simulation of electron acceleration in an underdense plasma

    Directory of Open Access Journals (Sweden)

    S Darvish Molla

    2011-06-01

    Full Text Available One of the interesting Laser-Plasma phenomena, when the laser power is high and ultra intense, is the generation of large amplitude plasma waves (Wakefield and electron acceleration. An intense electromagnetic laser pulse can create plasma oscillations through the action of the nonlinear pondermotive force. electrons trapped in the wake can be accelerated to high energies, more than 1 TW. Of the wide variety of methods for generating a regular electric field in plasmas with strong laser radiation, the most attractive one at the present time is the scheme of the Laser Wake Field Accelerator (LWFA. In this method, a strong Langmuir wave is excited in the plasma. In such a wave, electrons are trapped and can acquire relativistic energies, accelerated to high energies. In this paper the PIC simulation of wakefield generation and electron acceleration in an underdense plasma with a short ultra intense laser pulse is discussed. 2D electromagnetic PIC code is written by FORTRAN 90, are developed, and the propagation of different electromagnetic waves in vacuum and plasma is shown. Next, the accuracy of implementation of 2D electromagnetic code is verified, making it relativistic and simulating the generating of wakefield and electron acceleration in an underdense plasma. It is shown that when a symmetric electromagnetic pulse passes through the plasma, the longitudinal field generated in plasma, at the back of the pulse, is weaker than the one due to an asymmetric electromagnetic pulse, and thus the electrons acquire less energy. About the asymmetric pulse, when front part of the pulse has smaller time rise than the back part of the pulse, a stronger wakefield generates, in plasma, at the back of the pulse, and consequently the electrons acquire more energy. In an inverse case, when the rise time of the back part of the pulse is bigger in comparison with that of the back part, a weaker wakefield generates and this leads to the fact that the electrons

  6. High quality electron beams from a plasma channel guided laser wakefield accelerator

    International Nuclear Information System (INIS)

    Geddes, C.G.R.; Toth, Cs.; Tilborg, J. van; Esarey, E.; Schroeder, C.B.; Bruhwiler, D.; Nieter, C.; Cary, J.; Leemans, W.P.

    2004-01-01

    Laser driven accelerators, in which particles are accelerated by the electric field of a plasma wave driven by an intense laser, have demonstrated accelerating electric fields of hundreds of GV/m. These fields are thousands of times those achievable in conventional radiofrequency (RF) accelerators, spurring interest in laser accelerators as compact next generation sources of energetic electrons and radiation. To date however, acceleration distances have been severely limited by lack of a controllable method for extending the propagation distance of the focused laser pulse. The ensuing short acceleration distance results in low energy beams with 100% electron energy spread, limiting applications. Here we demonstrate that a relativistically intense laser can be guided by a preformed plasma density channel and that the longer propagation distance can result in electron beams of percent energy spread with low emittance and increased energy, containing >10 9 electrons above 80 MeV. The preformed plasma channel technique forms the basis of a new class of accelerators, combining beam quality comparable to RF accelerators with the high gradients of laser accelerators to produce compact tunable high brightness electron and radiation sources

  7. Survey on neutron production by electron beam from high power CW electron linear accelerator

    International Nuclear Information System (INIS)

    Toyama, S.

    1999-04-01

    In Japan Nuclear Cycle Development Institute, the development of high current CW electron linear accelerator is in progress. It is possible for an accelerator to produce neutrons by means of a spallation and photo nuclear reactions. Application of neutron beam produced by bremsstrahlung is one of ways of the utilization for high current electron accelerator. It is actual that many electron linear accelerators which maximum energy is higher than a few hundreds MeV are used as neutron sources. In this report, an estimate of neutron production is evaluated for high current CW electron linear accelerator. The estimate is carried out by 10 MeV beam which is maximum energy limited from the regulation and rather low for neutron production. Therefore, the estimate is also done by 17 and 35 MeV beam which is possible to be accelerated. Beryllium is considered as a target for lower electron energy in addition to Lead target for higher energy, because Beryllium has low threshold energy for neutron production. The evaluation is carried out in account of the target thickness optimized by the radiation length and neutron cross section reducing the energy loss for both of electron and neutron, so as to get the maximum number of neutrons. The result of the calculations shows neutron numbers 1.9 x 10 10 , 6.1 x 10 13 and 4.8 x 10 13 (n/s), respectively, for 10, 17, and 35 MeV with low duty. The thermal removal from the target is one of critical points. The additional shielding and cooling system is necessary in order to endure radiation. A comparison with other facilities are also carried out. The estimate of neutron numbers suggests the possibility to be applied for neutron radiography and measurement of nuclear data by means of Lead spectrometer, for example. (author)

  8. Electron acceleration in the bubble regime

    Energy Technology Data Exchange (ETDEWEB)

    Jansen, Oliver

    2014-02-03

    The bubble regime of laser-wakefield acceleration has been studied over the recent years as an important alternative to classical accelerators. Several models and theories have been published, in particular a theory which provides scaling laws for acceleration parameters such as energy gain and acceleration length. This thesis deals with numerical simulations within the bubble regime, their comparison to these scaling laws and data obtained from experiments, as well as some specific phenomenona. With a comparison of the scaling laws with numerical results a parameter scan was able to show a large parameter space in which simulation and theory agree. An investigation of the limits of this parameter space revealed boundaries to other regimes, especially at very high (a{sub 0} > 100) and very low laser amplitudes (a{sub 0} < 4). Comparing simulation data with data from experiments concerning laser pulse development and electron energies, it was found that experimental results can be adequately reproduced using the Virtual-Laser-Plasma-Laboratory code. In collaboration with the Institut fuer Optik und Quantenelektronik at the Friedrich-Schiller University Jena synchrotron radiation emitted from the inside of the bubble was investigated. A simulation of the movement of the electrons inside the bubble together with time dependent histograms of the emitted radiation helped to prove that the majority of radiation created during a bubble acceleration originates from the inside of the bubble. This radiation can be used to diagnose the amplitude of oscillation of the trapped electrons. During a further study it was proven that the polarisation of synchrotron radiation from a bubble contains information about the exact oscillation direction. This oscillation was successfully controlled by using either a laser pulse with a tilted pulse front or an asymmetric laser pulse. First results of ongoing studies concerning injecting electrons into an existing bubble and a scheme called

  9. Electron Heating and Acceleration in a Reconnecting Magnetotail

    Science.gov (United States)

    El-Alaoui, M.; Zhou, M.; Lapenta, G.; Berchem, J.; Richard, R. L.; Schriver, D.; Walker, R. J.

    2017-12-01

    Electron heating and acceleration in the magnetotail have been investigated intensively. A major site for this process is the reconnection region. However, where and how the electrons are accelerated in a realistic three-dimensional X-line geometry is not fully understood. In this study, we employed a three-dimensional implicit particle-in-cell (iPIC3D) simulation and large-scale kinetic (LSK) simulation to address these problems. We modeled a magnetotail reconnection event observed by THEMIS in an iPIC3D simulation with initial and boundary conditions given by a global magnetohydrodynamic (MHD) simulation of Earth's magnetosphere. The iPIC3D simulation system includes the region of fast outflow emanating from the reconnection site that drives dipolarization fronts. We found that current sheet electrons exhibit elongated (cigar-shaped) velocity distributions with a higher parallel temperature. Using LSK we then followed millions of test electrons using the electromagnetic fields from iPIC3D. We found that magnetotail reconnection can generate power law spectra around the near-Earth X-line. A significant number of electrons with energies higher than 50 keV are produced. We identified several acceleration mechanisms at different locations that were responsible for energizing these electrons: non-adiabatic cross-tail drift, betatron and Fermi acceleration. Relative contributions to the energy gain of these high energy electrons from the different mechanisms will be discussed.

  10. The electron accelerator for FELIX [Free Electron Laser for Infrared eXperiments

    International Nuclear Information System (INIS)

    Amersfoort, P.W. van; Geer, C.A.J. van der; Meer, A.F.G. van der; Bruinsma, P.J.T.; Hoekstra, R.; Kroes, F.B.; Luyckx, G.; Noomen, J.G.; Poole, M.W.; Saxon, G.

    1989-01-01

    The authors discuss the design of the electron accelerator for the Free Electron Laser for Infrared eXperiments (FELIX), which is meant to provide the Dutch science community with a rapidly tunable source of infrared radiation. The first stage of the project will (at least) cover the wavelength range between 8 and 80 μm. The accelerator consists of a triode with a grid modulated at 1 GHz, a 3.8-MeV buncher, and two travelling-wave S-band linac structures, with which 70-A, 3-ps bunches are accelerated to an energy between 15 and 4-5 MeV. The system has been designed to minimize the energy spread in the electron beam. 8 refs., 2 figs., 1 tab

  11. High power electron accelerators for flue gas treatment

    Energy Technology Data Exchange (ETDEWEB)

    Zimek, Z. [Institute of Nuclear Chemistry and Technology, Warsaw (Poland)

    2011-07-01

    Flue gas treatment process based on electron beam application for SO{sub 2} and NO{sub x} removal was successfully demonstrated in number of laboratories, pilot plants and industrial demonstration facilities. The industrial scale application of an electron beam process for flue gas treatment requires accelerators modules with a beam power 100-500 kW and electron energy range 0.8-1.5 MeV. The most important accelerator parameters for successful flue gas radiation technology implementation are related to accelerator reliability/availability, electrical efficiency and accelerator price. Experience gained in high power accelerators exploitation in flue gas treatment industrial demonstration facility was described and high power accelerator constructions have been reviewed. (author)

  12. High-energy coherent terahertz radiation emitted by wide-angle electron beams from a laser-wakefield accelerator

    Science.gov (United States)

    Yang, Xue; Brunetti, Enrico; Jaroszynski, Dino A.

    2018-04-01

    High-charge electron beams produced by laser-wakefield accelerators are potentially novel, scalable sources of high-power terahertz radiation suitable for applications requiring high-intensity fields. When an intense laser pulse propagates in underdense plasma, it can generate femtosecond duration, self-injected picocoulomb electron bunches that accelerate on-axis to energies from 10s of MeV to several GeV, depending on laser intensity and plasma density. The process leading to the formation of the accelerating structure also generates non-injected, sub-picosecond duration, 1–2 MeV nanocoulomb electron beams emitted obliquely into a hollow cone around the laser propagation axis. These wide-angle beams are stable and depend weakly on laser and plasma parameters. Here we perform simulations to characterise the coherent transition radiation emitted by these beams if passed through a thin metal foil, or directly at the plasma–vacuum interface, showing that coherent terahertz radiation with 10s μJ to mJ-level energy can be produced with an optical to terahertz conversion efficiency up to 10‑4–10‑3.

  13. Multistage linear electron acceleration using pulsed transmission lines

    International Nuclear Information System (INIS)

    Miller, R.B.; Prestwich, K.R.; Poukey, J.W.; Epstein, B.G.; Freeman, J.R.; Sharpe, A.W.; Tucker, W.K.; Shope, S.L.

    1981-01-01

    A four-stage linear electron accelerator is described which uses pulsed radial transmission lines as the basic accelerating units. An annular electron beam produced by a foilless diode is guided through the accelerator by a strong axial magnetic field. Synchronous firing of the injector and the acccelerating modules is accomplished with self-breaking oil switches. The device has accelerated beam currents of 25 kA to kinetic energies of 9 MV, with 90% current transport efficiency. The average accelerating gradient is 3 MV/m

  14. Electron acceleration by femtosecond laser interaction with micro-structured plasmas

    Science.gov (United States)

    Goers, Andy James

    Laser-driven accelerators are a promising and compact alternative to RF accelerator technology for generating relativistic electron bunches for medical, scientific, and security applications. This dissertation presents three experiments using structured plasmas designed to advance the state of the art in laser-based electron accelerators, with the goal of reducing the energy of the drive laser pulse and enabling higher repetition rate operation with current laser technology. First, electron acceleration by intense femtosecond laser pulses in He-like nitrogen plasma waveguides is demonstrated. Second, significant progress toward a proof of concept realization of quasi-phasematched direct acceleration (QPM-DLA) is presented. Finally, a laser wakefield accelerator at very high plasma density is studied, enabling relativistic electron beam generation with ˜10 mJ pulse energies. Major results from these experiments include: • Acceleration of electrons up to 120 MeV from an ionization injected wakefield accelerator driven in a 1.5 mm long He-like nitrogen plasma waveguide • Guiding of an intense, quasi-radially polarized femtosecond laser pulse in a 1 cm plasma waveguide. This pulse provides a strong drive field for the QPM-DLA concept. • Wakefield acceleration of electrons up to ˜10 MeV with sub-terawatt, ˜10 mJ pulses interacting with a thin (˜200 mum), high density (>1020 cm-3) plasma. • Observation of an intense, coherent, broadband wave breaking radiation flash from a high plasma density laser wakefield accelerator. The flash radiates > 1% of the drive laser pulse energy in a bandwidth consistent with half-cycle (˜1 fs) emission from violent unidirectional acceleration of electron bunches from rest. These results open the way to high repetition rate (>˜kHz) laser-driven generation of relativistic electron beams with existing laser technology.

  15. Development of new electron beam accelerator

    International Nuclear Information System (INIS)

    Tanaka, Jiro

    1976-01-01

    Approximately two decades have elapsed since electron accelerators were first employed in industry. It is widely used in the fields of chemical and food industries and the prevention of pollution. The accelerators for industrial use are limited to those obtainable high current or high output, low cost and easy handling. The low energy (up to 2 or 3 MeV) accelerators applicable to industry include the rectification type (Cockcroft, Dynamitron, Van de Graaff etc.), the AC transformer type (resonance transformer, cascade transformer) and the transformer type. As the accelerators of higher energy (more than 3 MeV), there exist the linear accelerator and the electromagnetic induction type. The linear accelerators are widely employed for industrial and medical uses as the large output can be obtained. Though various types of accelerators are used in industry, more increasing demands in accordance with the diversification of application are not always satisfied. As it seems that the realization of a new accelerator of improved performance and cost requires long time, it may be important to perform the standardization by dividing the energy and output ranges. (Wakatsuki, Y.)

  16. Direct longitudinal laser acceleration of electrons in free space

    Directory of Open Access Journals (Sweden)

    Sergio Carbajo

    2016-02-01

    Full Text Available Compact laser-driven accelerators are pursued heavily worldwide because they make novel methods and tools invented at national laboratories widely accessible in science, health, security, and technology [V. Malka et al., Principles and applications of compact laser-plasma accelerators, Nat. Phys. 4, 447 (2008]. Current leading laser-based accelerator technologies [S. P. D. Mangles et al., Monoenergetic beams of relativistic electrons from intense laser-plasma interactions, Nature (London 431, 535 (2004; T. Toncian et al., Ultrafast laser-driven microlens to focus and energy-select mega-electron volt protons, Science 312, 410 (2006; S. Tokita et al. Single-shot ultrafast electron diffraction with a laser-accelerated sub-MeV electron pulse, Appl. Phys. Lett. 95, 111911 (2009] rely on a medium to assist the light to particle energy transfer. The medium imposes material limitations or may introduce inhomogeneous fields [J. R. Dwyer et al., Femtosecond electron diffraction: “Making the molecular movie,”, Phil. Trans. R. Soc. A 364, 741 (2006]. The advent of few cycle ultraintense radially polarized lasers [S. Carbajo et al., Efficient generation of ultraintense few-cycle radially polarized laser pulses, Opt. Lett. 39, 2487 (2014] has ushered in a novel accelerator concept [L. J. Wong and F. X. Kärtner, Direct acceleration of an electron in infinite vacuum by a pulsed radially polarized laser beam, Opt. Express 18, 25035 (2010; F. Pierre-Louis et al. Direct-field electron acceleration with ultrafast radially polarized laser beams: Scaling laws and optimization, J. Phys. B 43, 025401 (2010; Y. I. Salamin, Electron acceleration from rest in vacuum by an axicon Gaussian laser beam, Phys. Rev. A 73, 043402 (2006; C. Varin and M. Piché, Relativistic attosecond electron pulses from a free-space laser-acceleration scheme, Phys. Rev. E 74, 045602 (2006; A. Sell and F. X. Kärtner, Attosecond electron bunches accelerated and

  17. Improvements to laser wakefield accelerated electron beam stability, divergence, and energy spread using three-dimensional printed two-stage gas cell targets

    International Nuclear Information System (INIS)

    Vargas, M.; Schumaker, W.; He, Z.-H.; Zhao, Z.; Behm, K.; Chvykov, V.; Hou, B.; Krushelnick, K.; Maksimchuk, A.; Yanovsky, V.; Thomas, A. G. R.

    2014-01-01

    High intensity, short pulse lasers can be used to accelerate electrons to ultra-relativistic energies via laser wakefield acceleration (LWFA) [T. Tajima and J. M. Dawson, Phys. Rev. Lett. 43, 267 (1979)]. Recently, it was shown that separating the injection and acceleration processes into two distinct stages could prove beneficial in obtaining stable, high energy electron beams [Gonsalves et al., Nat. Phys. 7, 862 (2011); Liu et al., Phys. Rev. Lett. 107, 035001 (2011); Pollock et al., Phys. Rev. Lett. 107, 045001 (2011)]. Here, we use a stereolithography based 3D printer to produce two-stage gas targets for LWFA experiments on the HERCULES laser system at the University of Michigan. We demonstrate substantial improvements to the divergence, pointing stability, and energy spread of a laser wakefield accelerated electron beam compared with a single-stage gas cell or gas jet target

  18. Improvements to laser wakefield accelerated electron beam stability, divergence, and energy spread using three-dimensional printed two-stage gas cell targets

    Energy Technology Data Exchange (ETDEWEB)

    Vargas, M.; Schumaker, W.; He, Z.-H.; Zhao, Z.; Behm, K.; Chvykov, V.; Hou, B.; Krushelnick, K.; Maksimchuk, A.; Yanovsky, V.; Thomas, A. G. R., E-mail: agrt@umich.edu [Center for Ultrafast Optical Science, University of Michigan, Ann Arbor, Michigan 48109 (United States)

    2014-04-28

    High intensity, short pulse lasers can be used to accelerate electrons to ultra-relativistic energies via laser wakefield acceleration (LWFA) [T. Tajima and J. M. Dawson, Phys. Rev. Lett. 43, 267 (1979)]. Recently, it was shown that separating the injection and acceleration processes into two distinct stages could prove beneficial in obtaining stable, high energy electron beams [Gonsalves et al., Nat. Phys. 7, 862 (2011); Liu et al., Phys. Rev. Lett. 107, 035001 (2011); Pollock et al., Phys. Rev. Lett. 107, 045001 (2011)]. Here, we use a stereolithography based 3D printer to produce two-stage gas targets for LWFA experiments on the HERCULES laser system at the University of Michigan. We demonstrate substantial improvements to the divergence, pointing stability, and energy spread of a laser wakefield accelerated electron beam compared with a single-stage gas cell or gas jet target.

  19. Electron Linacs for High Energy Physics

    International Nuclear Information System (INIS)

    Wilson, Perry B.

    2011-01-01

    The purpose of this article is to introduce some of the basic physical principles underlying the operation of electron linear accelerators (electron linacs). Electron linacs have applications ranging from linacs with an energy of a few MeV, such that the electrons are approximately relativistic, to future electron-positron linear colliders having a collision energy in the several-TeV energy range. For the most part, only the main accelerating linac is treated in this article.

  20. Stochastic acceleration of electrons from multiple uncorrelated plasma waves

    Science.gov (United States)

    Gee, David; Michel, Pierre; Wurtele, Jonathan

    2017-10-01

    One-dimensional theory puts a strict limit on the maximum energy attainable by an electron trapped and accelerated by an electron plasma wave (EPW). However, experimental measurements of hot electron distributions accelerated by stimulated Raman scattering (SRS) in ICF experiments typically show a thermal distribution with temperatures of the order of the kinetic energy of the resonant EPW's (Thot mvp2 , where vp is the phase velocity of the EPW's driven by SRS) and no clear cutoff at high energies. In this project, we are investigating conditions under which electrons can be stochastically accelerated by multiple uncorrelated EPW's, such as those generated by incoherent laser speckles in large laser spots like the ones used on NIF ( mm-size), and reproduce distributions similar to those observed in experiments. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract No. DE-AC52-07NA27344.

  1. Three electron beams from a laser-plasma wakefield accelerator and the energy apportioning question

    CERN Document Server

    Yang, X; Reboredo Gil, David; Welsh, Gregor H; Li, Y.F; Cipiccia, Silvia; Ersfeld, Bernhard; Grant, D. W; Grant, P. A; Islam, Muhammad; Tooley, M.B; Vieux, Gregory; Wiggins, Sally; Sheng, Zheng-Ming; Jaroszynski, Dino

    2017-01-01

    Laser-wakefield accelerators are compact devices capable of delivering ultra-short electron bunches with pC-level charge and MeV-GeV energy by exploiting the ultra-high electric fields arising from the interaction of intense laser pulses with plasma. We show experimentally and through numerical simulations that a high-energy electron beam is produced simultaneously with two stable lowerenergy beams that are ejected in oblique and counter-propagating directions, typically carrying off 5–10% of the initial laser energy. A MeV, 10s nC oblique beam is ejected in a 30°–60° hollow cone, which is filled with more energetic electrons determined by the injection dynamics. A nC-level, 100s keV backward-directed beam is mainly produced at the leading edge of the plasma column. We discuss the apportioning of absorbed laser energy amongst the three beams. Knowledge of the distribution of laser energy and electron beam charge, which determine the overall efficiency, is important for various applications of laser-wake...

  2. Positron annihilation induced Auger electron spectroscopy and its implementation at accelerator based low energy positron factories

    International Nuclear Information System (INIS)

    Weiss, A.; Koeymen, A.R.; Mehl, D.; Lee, K.H.; Yang Gimo; Jensen, K.

    1991-01-01

    Positron annihilation induced auger electron spectroscopy (PAES) makes use of a beam of low energy positrons to excite Auger transitions by annihilating core electrons. The large secondary electron background usually present in Auger spectra can be eliminated by setting the positron beam energy well below the Auger electron energy. This allows true Auger lineshapes to be obtained. Further, because the positron is localized just outside the surface before it annihilates, PAES is extremely sensitive to the topmost atomic layer. Recent PAES results obtained at the University of Texas at Arlington will be presented. In addition, the use of high resolution energy analyzers with multichannel particle detection schemes to prevent problems due to the high data rates associated with accelerator based positron beams will be discussed. (orig.)

  3. Radiation processing of liquid with low energy electron accelerator

    International Nuclear Information System (INIS)

    Makuuchi, Keizo

    2003-01-01

    Radiation induced emulsion polymerization, radiation vulcanization of NR latex (RVNRL) and radiation degradation of natural polymers were selected and reviewed as the radiation processing of liquid. The characteristic of high dose rate emulsion polymerization is the occurrence of cationic polymerization. Thus, it can be used for the production of new materials that cannot be obtained by radical polymerization. A potential application will be production of polymer emulsion that can be used as water-borne UV/EB curing resins. The technology of RVNRL by γ-ray has been commercialized. RVNRL with low energy electron accelerator is under development for further vulcanization cost reduction. Vessel type irradiator will be favorable for industrial application. Radiation degradation of polysaccharides is an emerging and promising area of radiation processing. However, strict cost comparison between liquid irradiation with low energy EB and state irradiation with γ-ray should be carried out. (author)

  4. Radiation processing of liquid with low energy electron accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Makuuchi, Keizo [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

    2003-02-01

    Radiation induced emulsion polymerization, radiation vulcanization of NR latex (RVNRL) and radiation degradation of natural polymers were selected and reviewed as the radiation processing of liquid. The characteristic of high dose rate emulsion polymerization is the occurrence of cationic polymerization. Thus, it can be used for the production of new materials that cannot be obtained by radical polymerization. A potential application will be production of polymer emulsion that can be used as water-borne UV/EB curing resins. The technology of RVNRL by {gamma}-ray has been commercialized. RVNRL with low energy electron accelerator is under development for further vulcanization cost reduction. Vessel type irradiator will be favorable for industrial application. Radiation degradation of polysaccharides is an emerging and promising area of radiation processing. However, strict cost comparison between liquid irradiation with low energy EB and state irradiation with {gamma}-ray should be carried out. (author)

  5. Experimental studies of VpxB electron linear accelerator

    International Nuclear Information System (INIS)

    Taura, T.; Onihashi, H.; Otsuka, K.; Nishida, Y.; Yugami, N.

    1989-01-01

    In order to demonstrate a new electron linear accelerator an electron beam is accelerated either in the conventional linear accelerator scheme or in the V p xB scheme in a same machine and higher energy gain of about 18 % is observed in the V p xB scheme as is expected from the designed values. The experimental results are compared with the numerical simulation to show reasonable agreement. (author)

  6. High brightness electron accelerator

    International Nuclear Information System (INIS)

    Sheffield, R.L.; Carlsten, B.E.; Young, L.M.

    1994-01-01

    A compact high brightness linear accelerator is provided for use, e.g., in a free electron laser. The accelerator has a first plurality of accelerating cavities having end walls with four coupling slots for accelerating electrons to high velocities in the absence of quadrupole fields. A second plurality of cavities receives the high velocity electrons for further acceleration, where each of the second cavities has end walls with two coupling slots for acceleration in the absence of dipole fields. The accelerator also includes a first cavity with an extended length to provide for phase matching the electron beam along the accelerating cavities. A solenoid is provided about the photocathode that emits the electrons, where the solenoid is configured to provide a substantially uniform magnetic field over the photocathode surface to minimize emittance of the electrons as the electrons enter the first cavity. 5 figs

  7. Online beam energy measurement of Beijing electron positron collider II linear accelerator

    Science.gov (United States)

    Wang, S.; Iqbal, M.; Liu, R.; Chi, Y.

    2016-02-01

    This paper describes online beam energy measurement of Beijing Electron Positron Collider upgraded version II linear accelerator (linac) adequately. It presents the calculation formula, gives the error analysis in detail, discusses the realization in practice, and makes some verification. The method mentioned here measures the beam energy by acquiring the horizontal beam position with three beam position monitors (BPMs), which eliminates the effect of orbit fluctuation, and is much better than the one using the single BPM. The error analysis indicates that this online measurement has further potential usage such as a part of beam energy feedback system. The reliability of this method is also discussed and demonstrated in this paper.

  8. Electron cyclotron wave acceleration outside a flaring loop

    Science.gov (United States)

    Sprangle, P.; Vlahos, L.

    1983-01-01

    A model for the secondary acceleration of electrons outside a flaring loop is proposed. The results suggest that the narrow bandwidth radiation emitted by the unstable electron distribution inside a flaring loop can become the driver for secondary electron acceleration outside the loop. It is shown that a system of electrons gyrating about and streaming along an adiabatically spatially varying, static magnetic field can be efficiently accelerated to high energies by an electromagnetic wave propagating along and polarized transverse to the static magnetic field. The predictions from our model appear to be in general agreement with existing observations.

  9. Electron cyclotron wave acceleration outside a flaring loop

    International Nuclear Information System (INIS)

    Sprangle, P.; Vlahos, L.

    1983-01-01

    We propose a model for the secondary acceleration of electrons outside a flaring loop. Our results suggest that the narrow bandwidth radiation emitted by the unstable electron distribution inside a flaring loop can become the driver for secondary electron acceleration outside the loop. We show that a system of electrons gyrating about and streaming along an adiabatically spatially varying, static magnetic field can be efficiently accelerated to high energies by an electromagnetic wave propagating along and polarized transverse to the static magnetic field. The predictions from our model appear to be in general agreement with existing observations

  10. High-Power Electron Accelerators for Space (and other) Applications

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, Dinh Cong [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Lewellen, John W. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-05-23

    This is a presentation on high-power electron accelerators for space and other applications. The main points covered are: electron beams for space applications, new designs of RF accelerators, high-power high-electron mobility transistors (HEMT) testing, and Li-ion battery design. In summary, the authors have considered a concept of 1-MeV electron accelerator that can operate up to several seconds. This concept can be extended to higher energy to produce higher beam power. Going to higher beam energy requires adding more cavities and solid-state HEMT RF power devices. The commercial HEMT have been tested for frequency response and RF output power (up to 420 W). Finally, the authors are testing these HEMT into a resonant load and planning for an electron beam test in FY17.

  11. Electromagnetic Structure and Electron Acceleration in Shock–Shock Interaction

    Energy Technology Data Exchange (ETDEWEB)

    Nakanotani, Masaru [Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, 6-1 Kasuga-Koen, Kasuga, Fukuoka, 816-8580 (Japan); Matsukiyo, Shuichi; Hada, Tohru [Faculty of Engineering Sciences, Kyushu University, 6-1 Kasuga-Koen, Kasuga, Fukuoka, 816-8580 (Japan); Mazelle, Christian X., E-mail: nakanot@esst.kyushu-u.ac.jp [IRAP, Université Paul Sabatier Toulouse III-CNRS, F-31028 Toulouse Cedex 4 (France)

    2017-09-10

    A shock–shock interaction is investigated by using a one-dimensional full particle-in-cell simulation. The simulation reproduces the collision of two symmetrical high Mach number quasi-perpendicular shocks. The basic structure of the shocks and ion dynamics is similar to that obtained by previous hybrid simulations. The new aspects obtained here are as follows. Electrons are already strongly accelerated before the two shocks collide through multiple reflection. The reflected electrons self-generate waves upstream between the two shocks before they collide. The waves far upstream are generated through the right-hand resonant instability with the anomalous Doppler effect. The waves generated near the shock are due to firehose instability and have much larger amplitudes than those due to the resonant instability. The high-energy electrons are efficiently scattered by the waves so that some of them gain large pitch angles. Those electrons can be easily reflected at the shock of the other side. The accelerated electrons form a power-law energy spectrum. Due to the accelerated electrons, the pressure of upstream electrons increases with time. This appears to cause the deceleration of the approaching shock speed. The accelerated electrons having sufficiently large Larmor radii are further accelerated through the similar mechanism working for ions when the two shocks are colliding.

  12. Electron accelerators and nuclear physics

    International Nuclear Information System (INIS)

    Frois, B.

    1989-01-01

    The operating electron accelerators and their importance in the nuclear and in the particle physics developments, are underlined. The principles of probing the nucleus by applying electron scattering techniques and the main experimental results, are summarized. In order to understand hadron interactions and the dynamics of quark confinement in nuclei, the high energy electrons must provide quantitative data on the following topics: the structure of the nucleon, the role of non nucleonic components in nuclei, the nature of short-range nucleon correlations, the origin of the short-range part of nuclear forces and the effects of the nuclear medium on quark distributions. To progress in the nuclear structure knowledge it is necessary to build a coherent strategy of accelerator developments in Europe

  13. Intermediate energy electron cooling for antiproton sources using a Pelletron accelerator

    International Nuclear Information System (INIS)

    Cline, D.B.; Adney, J.; Ferry, J.; Kells, W.; Larson, D.J.; Mills, F.E.; Sundquist, M.

    1983-01-01

    It has been shown at FNAL that the electron cooling of protons is a very efficient method for reaching high luminosity in a proton beam. The emittance of the 120 KeV electron beam used at Fermilab corresponds to a cathode temperature of 0.1 eV. In order to apply cooling techniques to GeV proton beams the electron energies required are in the MeV range. In the experiment reported in this paper the emittance of a 3-MeV Pelletron electron accelerator was measured to determine that its emittance scaled to a value appropriate for electron cooling. The machine tested was jointly owned and operated by the University of California at Santa Barbara and National Electrostatics Corporation for research into free-electron lasers which also require low emittance beams for operation. This paper describes the thermal emittance of the beam to be the area in phase space in which 90% of the beam trajectories lie and goes on to describe the emittance-measurement method both in theory and application

  14. Unlimited electron acceleration in laser-driven plasma waves

    International Nuclear Information System (INIS)

    Katsouleas, T.; Dawson, J.M.

    1983-01-01

    It is shown that the limitation to the energy gain of 2(ω/ω/sub p/) 2 mc 2 of an electron in the laser-plasma beat-wave accelerator can be overcome by imposing a magnetic field of appropriate strength perpendicular to the plasma wave. This accelerates particles parallel to the phase fronts of the accelerating wave which keeps them in phase with it. Arbitrarily large energy is theoretically possible

  15. Electron beam accelerator facilities at IPEN-CNEN/SP

    Energy Technology Data Exchange (ETDEWEB)

    Somessari, Samir L.; Silveira, Carlos G. da; Paes, Helio; Somessari, Elizabeth S.R. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)], E-mail: somessar@ipen.br

    2007-07-01

    Electron beam processing is a manufacturing technique, which applies a focused beam of high-energy electrons produced by an electron accelerator to promote chemical changes within a product. At IPEN-CNEN/SP there are two electron beam accelerators Type Dynamitron{sup R} (manufactured by RDI- Radiation Dynamics Inc.) Job 188 and Job 307 models. The technical specifications for the Job 188 energy 1.5 MeV, beam current 25 mA, scan 1.20 m, beam power 37.5 kW and for the Job 307 energy 1.5 MeV, beam current 65 mA, Scan 1.20 m, beam power 97.5 kW. Some applications of the electron beam accelerator for radiation processing are wire and cable insulation crosslinking, rubber vulcanization, sterilization and disinfection of medical products, food preservation, heat shrinkable products, polymer degradation, aseptic packaging, semiconductors and pollution control. For irradiating these materials at IPEN-CNEN/SP, there are some equipment such as, underbeam capstan with speed control from 10 to 700 m/min; a track; a system to roll up and unroll wires and electric cables, polyethylene blankets and other systems to improve the quality of the products. (author)

  16. ELECTRON ACCELERATION BY MULTI-ISLAND COALESCENCE

    International Nuclear Information System (INIS)

    Oka, M.; Phan, T.-D.; Krucker, S.; Fujimoto, M.; Shinohara, I.

    2010-01-01

    Energetic electrons of up to tens of MeV are created during explosive phenomena in the solar corona. While many theoretical models consider magnetic reconnection as a possible way of generating energetic electrons, the precise roles of magnetic reconnection during acceleration and heating of electrons still remain unclear. Here, we show from two-dimensional particle-in-cell simulations that coalescence of magnetic islands that naturally form as a consequence of tearing mode instability and associated magnetic reconnection leads to efficient energization of electrons. The key process is the secondary magnetic reconnection at the merging points, or the 'anti-reconnection', which is, in a sense, driven by the converging outflows from the initial magnetic reconnection regions. By following the trajectories of the most energetic electrons, we found a variety of different acceleration mechanisms but the energization at the anti-reconnection is found to be the most important process. We discuss possible applications to the energetic electrons observed in the solar flares. We anticipate our results to be a starting point for more sophisticated models of particle acceleration during the explosive energy release phenomena.

  17. Performance review of thermionic electron gun developed for RF linear accelerators at RRCAT

    International Nuclear Information System (INIS)

    Wanmode, Yashwant; Mulchandani, J.; Reddy, T.S.; Bhisikar, A.; Singh, H.G.; Shrivastava, Purushottam

    2015-01-01

    RRCAT is engaged in development of RF electron linear accelerator for irradiation of industrial and agricultural products. Thermionic electron gun is primary source for this accelerator as beam current in the RF accelerator is modest and thermionic emission is most prevalent option for electron gun development. An electron gun has to meet high cathode emission capability, low filament power, good accessibility for cathode replacement and should provide short time for maintenance. Electron linear accelerator up to beam energy of 10 MeV require electron source of 45-50 keV beam energy and emission current of 1 A. Electron optics of gun and electron beam profile simulations were carried out using CST's particle tracking code and EGUN code. Triode type electron gun of cathode voltage 50 kV pulsed has been designed, developed and integrated with 10 MeV electron linear accelerators at RRCAT. Beam current of more than 600 mA has been measured with faraday cup in the test stand developed for characterizing the electron gun. Two accelerators one is imported and another one developed indigenously has been energized using this electron gun. Beam energy of 5-10 MeV has been achieved with beam current of 250-400 mA by integrating this electron gun with the linear accelerator. This paper reviews the performance of indigenously developed electron gun for both linear accelerators. (author)

  18. Plasma accelerators at the energy frontier and on tabletops

    CERN Document Server

    Joshi, Chandrashekhar

    2003-01-01

    New approaches to charged-particle acceleration by collective fields in plasma were discussed. These approaches show considerable promise for realizing plasma accelerators at the energy frontier as well as table-top electron and ion accelerators. Charged particles surfing on electron density waves in plasmas can experience enormous accelerating gradients. (Edited abstract) 45 Refs.

  19. Calculation of the electron trajectory for 200 kV self-shielded electron accelerator

    International Nuclear Information System (INIS)

    Wang Shuiqing

    2000-01-01

    In order to calculate the electron trajectory of 200 kV self-shielded electron accelerator, the electric field is calculated with a TRAJ program. In this program, following electron track mash points one by one, the electron beam trajectories are calculated. Knowing the effect of grid voltage on electron optics and gaining grid voltage focusing effect in the various energy grades, the authors have gained scientific basis for adjusting grid voltage, and also accumulated a wealth of experience for designing self-shielded electron accelerator or electron curtain in future

  20. High quality electron beams from a laser wakefield accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Wiggins, S M; Issac, R C; Welsh, G H; Brunetti, E; Shanks, R P; Anania, M P; Cipiccia, S; Manahan, G G; Aniculaesei, C; Ersfeld, B; Islam, M R; Burgess, R T L; Vieux, G; Jaroszynski, D A [SUPA, Department of Physics, University of Strathclyde, Glasgow (United Kingdom); Gillespie, W A [SUPA, Division of Electronic Engineering and Physics, University of Dundee, Dundee (United Kingdom); MacLeod, A M [School of Computing and Creative Technologies, University of Abertay Dundee, Dundee (United Kingdom); Van der Geer, S B; De Loos, M J, E-mail: m.wiggins@phys.strath.ac.u [Pulsar Physics, Burghstraat 47, 5614 BC Eindhoven (Netherlands)

    2010-12-15

    High quality electron beams have been produced in a laser-plasma accelerator driven by femtosecond laser pulses with a peak power of 26 TW. Electrons are produced with an energy up to 150 MeV from the 2 mm gas jet accelerator and the measured rms relative energy spread is less than 1%. Shot-to-shot stability in the central energy is 3%. Pepper-pot measurements have shown that the normalized transverse emittance is {approx}1{pi} mm mrad while the beam charge is in the range 2-10 pC. The generation of high quality electron beams is understood from simulations accounting for beam loading of the wakefield accelerating structure. Experiments and self-consistent simulations indicate that the beam peak current is several kiloamperes. Efficient transportation of the beam through an undulator is simulated and progress is being made towards the realization of a compact, high peak brilliance free-electron laser operating in the vacuum ultraviolet and soft x-ray wavelength ranges.

  1. Potential application of electron accelerators in Malaysia

    Energy Technology Data Exchange (ETDEWEB)

    Alang Md Rashid, Nahrul Khair; Mohd Dahlan, Khairul Zaman [Nuclear Energy Unit, Bangi, Selangor (Malaysia)

    1994-12-31

    Briefly discussed some applications of electron accelerators i.e. sterilization, pasteurization (high energy EBM - up to 10 MV), crosslinking of wire and cable and insulation (medium energy EBM - 1 to 5 MV), treatment of flue gases for removal of NO sub x and SO sub x from burning coal(low energy EBM - 700 to 900 kV), curing of surface coatings, printing ink, adhesives (low energy EBM - 200 to 500 kV); advantages and electron beam processing.

  2. Potential application of electron accelerators in Malaysia

    International Nuclear Information System (INIS)

    Nahrul Khair Alang Md Rashid; Khairul Zaman Mohd Dahlan

    1994-01-01

    Briefly discussed some applications of electron accelerators i.e. sterilization, pasteurization (high energy EBM - up to 10 MV), crosslinking of wire and cable and insulation (medium energy EBM - 1 to 5 MV), treatment of flue gases for removal of NO sub x and SO sub x from burning coal(low energy EBM - 700 to 900 kV), curing of surface coatings, printing ink, adhesives (low energy EBM - 200 to 500 kV); advantages and electron beam processing

  3. Application of TSEE characteristics to high energy radiation dosimetry around an electron linear accelerator

    International Nuclear Information System (INIS)

    Yamamoto, T.; Nakasaku, S.; Kawanishi, M.

    1986-01-01

    The response of the exoelectron dosemeter to the absorbed dose has been investigated with the LiF sample irradiated with high energy electrons from a linear accelerator and γ rays from a 60 Co source. The energy absorbed in the thin surface layer, which can be related to the origins of exoelectron emission, is, in general, smaller than the energy liberated there by primary radiation. In this paper the surface dose is calculated by the Monte Carlo Code EGS4. It is pointed out that the air layer in front of the sample also plays an important role by supplying secondary electrons to the surface region of the sample. The emission density of exoelectrons from a LiF single crystal for unit absorbed dose is found to be 5 x 10 4 electrons.cm -2 .Gy -1 , and nearly constant independent of the low LET radiation type. (author)

  4. Accelerators in industrial electron beam processing

    International Nuclear Information System (INIS)

    Becker, R.C.

    1984-01-01

    High power electron beam accelerators are being used for a variety of industrial processes. Such machines can process a wide range of products at very high thruput rates and at very low unit processing costs. These industrial accelerators are now capable of producing up to 200 kW of electron beam power at 4.0 MV and 100 kW at 5.0 MV. At this writing, even larger units are contemplated. The reliability of these high power devices also makes it feasible to consider bremsstrahlung (x-ray) processing as well. In addition to the advance of accelerator technology, microprocessor control systems now provide the capability to coordinate all the operations of the irradiation facility, including the accelerator, the material handling system, the personnel safety system and various auxiliary services. Facility designs can be adapted to many different industrial processes, including use of the dual purpose electron/x-ray accelerator, to ensure satisfactory product treatment with good dose uniformity, high energy efficiency and operational safety and simplicity. In addition, equipment manufacturers like RDI are looking beyond their conventional DC accelerator technology; looking at high power 10-12 MeV linear accelerators with power levels up to 25 kW or more. These high power linear accelerators could be the ideal processing tool for many sterilization and food irradiation applications. (author)

  5. Pulsed electron accelerator for radiation technologies in the enviromental applications

    Science.gov (United States)

    Korenev, Sergey

    1997-05-01

    The project of pulsed electron accelerator for radiation technologies in the environmental applications is considered. An accelerator consists of high voltage generator with vacuum insulation and vacuum diode with plasma cathode on the basis discharge on the surface of dielectric of large dimensions. The main parameters of electron accelerators are following: kinetic energy 0.2 - 2.0 MeV, electron beam current 1 - 30 kA and pulse duration 1- 5 microseconds. The main applications of accelerator for decomposition of wastewaters are considered.

  6. Concerning the maximum energy of ions accelerated at the front of a relativistic electron cloud expanding into vacuum

    International Nuclear Information System (INIS)

    Bulanov, S.V.; Esirkepov, T.Zh.; Koga, J.; Tajima, T.; Farina, D.

    2004-01-01

    Results of particle-in-cell simulations are presented that demonstrate characteristic interaction regimes of high-power laser radiation with plasma. It is shown that the maximum energy of fast ions can substantially exceed the electron energy. A theoretical model is proposed of ion acceleration at the front of a relativistic electron cloud expanding into vacuum in the regime of strong charge separation. The model describes the electric field structure and the dynamics of fast ions inside the electron cloud. The maximum energy the ions can gain at the front of the expanding electron cloud is found

  7. Optimization and application of electron acceleration in relativistic laser plasmas

    International Nuclear Information System (INIS)

    Koenigstein, Thomas

    2013-01-01

    This thesis describes experiments and simulations of the acceleration of electrons to relativistic energies (toward γ e ∼ 10 3 ) by structures in plasmas which are generated by ultrashort (pulse length < 10 -14 s) laser pulses. The first part of this work discusses experiments in a parameter space where quasimonoenergetic electron bunches are generated in subcritical (gaseous) plasmas and compares them to analytical scalings. A primary concern in this work is to optimize the stability of the energy and the pointing of the electrons. The second part deals with acceleration of electrons along the surface of solid substrates by laser-plasma interaction. The measurements show good agreement with existing analytical scalings and dedicated numerical simulations. In the third part, two new concepts for multi-stage acceleration will be presented and parameterised by analytical considerations and numerical simulations. The first method uses electron pairs, as produced in the first part, to transfer energy from the first bunch to the second by means of a plasma wave. The second method utilizes a low intensity laser pulse in order to inject electrons from a neutral gas into the accelerating phase of a plasma wave. The final chapter proposes and demonstrates a first application that has been developed in collaboration with ESA. The use of electron beams with exponential energy distribution, as in the second part of this work, offers the potential to investigate the resistance of electronic components against space radiation exposure.

  8. En Route: next-generation laser-plasma-based electron accelerators

    International Nuclear Information System (INIS)

    Hidding, Bernhard

    2008-05-01

    Accelerating electrons to relativistic energies is of fundamental interest, especially in particle physics. Today's accelerator technology, however, is limited by the maximum electric fields which can be created. This thesis presents results on various mechanisms aiming at exploiting the fields in focussed laser pulses and plasma waves for electron acceleration, which can be orders of magnitude higher than with conventional accelerators. With relativistic, underdense laser-plasma-interaction, quasimonoenergetic electron bunches with energies up to ∼50 MeV and normalized emittances of the order of 5mmmrad have been generated. This was achieved by focussing the ∼80 fs, 1 J pulses of the JETI-laser at the FSU Jena to intensities of several 10 19 W=cm 2 into gas jets. The experimental observations could be explained via ''bubble acceleration'', which is based on self-injection and acceleration of electrons in a highly nonlinear breaking plasma wave. For the rst time, this bubble acceleration was achieved explicitly in the self-modulated laser wakefield regime (SMLWFA). This quasimonoenergetic SMLWFA-regime stands out by relaxing dramatically the requirements on the driving laser pulse necessary to trigger bubble acceleration. This is due to self-modulation of the laser pulse in high-density gas jets, leading to ultrashort laser pulse fragments capable of initiating bubble acceleration. Electron bunches with durations < or similar 5 fs can thus be created, which is at least an order of magnitude shorter than with conventional accelerator technology. In addition, more than one laser pulse fragment can be powerful enough to drive a bubble. Distinct double peaks have been observed in the electron spectra, indicating that two quasimonoenergetic electron bunches separated by only few tens of fs have formed. This is backed up by PIC-Simulations (Particle-in-Cell). These results underline the feasibility of the construction of small table-top accelerators, while at the

  9. Electron acceleration by longitudinal electric field of a gaussian laser beam

    International Nuclear Information System (INIS)

    Takeuchi, Satoshi; Sugihara, Ryo; Shimoda, Koichi.

    1991-11-01

    It is shown that the longitudinal electric field of a transverse magnetic mode of a Gaussian laser beam accelerates an electron to an ultra-relativistic energy. The electron is captured and accelerated in a length of the order of the Rayleigh range. The ultimate energy increment of the electron with a single laser beam is given by the product of transverse field intensity and the beam waist, and can be of the order of 100MeV. This fact implies that a multi-stage acceleration enables TeV-order-acceleration in a length of a few kilometers with the present state of the art. (author)

  10. Low energy spread 100 MeV-1 GeV electron bunches from laser wakefield acceleration at LOASIS

    International Nuclear Information System (INIS)

    Geddes, C.G.R.; Esarey, E.; Michel, P.; Nagler, B.; Nakamura, K.; Plateau, G.R.; Schroeder, C.B.; Shadwick, B.A.; Toth, Cs.; Van Tilborg, J.; Leemans, W.P.; Hooker, S.M.; Gonsalves, A.J.; Michel, E.; Cary, J.R.; Bruhwiler, D.

    2006-01-01

    Experiments at the LOASIS laboratory of LBNL recently demonstrated production of 100 MeV electron beams with low energy spread and low divergence from laser wakefield acceleration. The radiation pressure of a 10 TW laser pulse guided over 10 diffraction ranges by a plasma density channel was used to drive an intense plasma wave (wakefield), producing acceleration gradients on the order of 100 GV/m in a mm-scale channel. Beam energy has now been increased from 100 to 1000 MeV by using a cm-scale guiding channel at lower density, driven by a 40TW laser, demonstrating the anticipated scaling to higher beam energies. Particle simulations indicate that the low energy spread beams were produced from self trapped electrons through the interplay of trapping, loading, and dephasing. Other experiments and simulations are also underway to control injection of particles into the wake, and hence improve beam quality and stability further

  11. Utilization of electron beam accelerators for polymer processing

    International Nuclear Information System (INIS)

    Sarma, K.S.S.

    2013-01-01

    During the last decade, electron beam processing has been amply demonstrated to the Indian cable industry by BARC using 2 MeV/20 kW electron beam (EB) accelerator (ILU-6 EBA facility) located at BARC-BRIT complex, Vashi. The electron beam accelerator is a machine producing high energy electrons which are made to impinge on the materials for inducing physical, chemical and biological modifications. The process is carried out at room temperature and in ambient atmospheric conditions. Lately, quite a few numbers of accelerators have been installed by the private cable industry and carrying out cross-linking of cable insulations for high performance viz. high temperature stability, good flame retardancy, lesser solvent-swelling, thinner insulations etc. The indigenously made accelerators at EB centre, particularly the 3 MeV/30 kW accelerator will be of much help for Indian industry for polymer processing as the market is poised to grow by adapting the technology

  12. NONTHERMALLY DOMINATED ELECTRON ACCELERATION DURING MAGNETIC RECONNECTION IN A LOW-β PLASMA

    International Nuclear Information System (INIS)

    Li, Xiaocan; Li, Gang; Guo, Fan; Li, Hui

    2015-01-01

    By means of fully kinetic simulations, we investigate electron acceleration during magnetic reconnection in a nonrelativistic proton–electron plasma with conditions similar to solar corona and flares. We demonstrate that reconnection leads to a nonthermally dominated electron acceleration with a power-law energy distribution in the nonrelativistic low-β regime but not in the high-β regime, where β is the ratio of the plasma thermal pressure and the magnetic pressure. The accelerated electrons contain most of the dissipated magnetic energy in the low-β regime. A guiding-center current description is used to reveal the role of electron drift motions during the bulk nonthermal energization. We find that the main acceleration mechanism is a Fermi-type acceleration accomplished by the particle curvature drift motion along the electric field induced by the reconnection outflows. Although the acceleration mechanism is similar for different plasma β, low-β reconnection drives fast acceleration on Alfvénic timescales and develops power laws out of thermal distribution. The nonthermally dominated acceleration resulting from magnetic reconnection in low-β plasma may have strong implications for the  highly efficient electron acceleration in solar flares and other astrophysical systems

  13. Compact high-current, subnanosecond electron accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Shpak, V G; Shunajlov, S A; Ulmaskulov, M R; Yalandin, M I [Russian Academy of Sciences, Ekaterinburg (Russian Federation). Inst. of Electrophysics; Pegel, I V [Russian Academy of Sciences, Tomsk (Russian Federation). High-Current Electronics Inst.; Tarakanov, V P [Russian Academy of Sciences, Moscow (Russian Federation). High-Temperature Inst.

    1997-12-31

    A compact subnanosecond, high-current electron accelerator producing an annular electron beam of duration up to 300 - 400 ps, energy about 250 keV, and current up to 1 kA has been developed to study transient processes in pulsed power microwave devices. The measuring and recording techniques used to experimentally investigate the dynamics of the beam current pulse and the transformation of the electron energy during the transportation of the beam in a longitudinal magnetic field are described. The experimental data obtained are compared with the predictions of a numerical simulation. (author). 6 figs., 5 refs.

  14. Operation of the graded-β electron test accelerator

    International Nuclear Information System (INIS)

    Fraser, J.S.; McKeown, J.; McMichael, G.E.; Diamond, W.T.

    1976-01-01

    The Electron Test Accelerator has been built to model the behaviour of the high energy portion of a proton linear accelerator which would be suitable for breeding fissile material. The test accelerator and its control systems have been tested at 100% duty factor producing a beam of electrons at 1.5 MeV and currents up to 20 mA where the incident rf power is shared equally between the structure dissipation and the beam loading. The structure has performed satisfactorily in all respects at dissipation power densities up to 5 kW/cell where the mean energy gradient was 1.1 MeV/m. Experiments have been done on the beam loading effects in the coupling of the transmission line to the cavity, the amplitude depression in and phase tilt along the structure, and the phase lag of the structure field. The phase acceptance, the variation of transmission with buncher-accelerator phase shift and the beam energy spread are in qualitative agreement with beam dynamics calculations. (author)

  15. An inverse free electron laser accelerator: Experiment and theoretical interpretation

    International Nuclear Information System (INIS)

    Fang, Jyan-Min.

    1997-01-01

    Experimental and numerical studies of the Inverse Free Electron Laser using a GW-level 10.6 μm CO 2 laser have been carried out at Brookhaven's Accelerator Test Facility. An energy gain of 2.5 % (ΔE/E) on a 40 MeV electron beam has been observed E which compares well with theory. The effects on IFEL acceleration with respect to the variation of the laser electric field, the input electron beam energy, and the wiggler magnetic field strength were studied, and show the importance of matching the resonance condition in the IFEL. The numerical simulations were performed under various conditions and the importance of the electron bunching in the IFEL is shown. The numerical interpretation of our IFEL experimental results was examined. Although good numerical agreement with the experimental results was obtained, there is a discrepancy between the level of the laser power measured in the experiment and used in the simulation, possibly due to the non-Gaussian profile of the input high power laser beam. The electron energy distribution was studied numerically and a smoothing of the energy spectrum by the space charge effect at the location of the spectrometer was found, compared with the spectrum at the exit of the wiggler. The electron bunching by the IFEL and the possibility of using the IFEL as an electron prebuncher for another laser-driven accelerator were studied numerically. We found that bunching of the electrons at 1 meter downstream from the wiggler can be achieved using the existing facility. The simulation shows that there is a fundamental difference between the operating conditions for using the IFEL as a high gradient accelerator, and as a prebuncher for another accelerator

  16. Design of cavities of a standing wave accelerating tube for a 6 MeV electron linear accelerator

    Directory of Open Access Journals (Sweden)

    S Zarei

    2017-08-01

    Full Text Available Side-coupled standing wave tubes in  mode are widely used in the low-energy electron linear accelerator, due to high accelerating gradient and low sensitivity to construction tolerances. The use of various simulation software for designing these kinds of tubes is very common nowadays. In this paper, SUPERFISH code and COMSOL are used for designing the accelerating and coupling cavities for a 6 MeV electron linear accelerator. Finite difference method in SUPERFISH code and Finite element method in COMSOL are used to solve the equations. Besides, dimension of accelerating and coupling cavities and also coupling iris dimension are optimized to achieve resonance frequency of 2.9985 MHz and coupling constant of 0.0112. Considering the results of this study and designing of the RF energy injection port subsequently, the construction of 6 MeV electron tube will be provided

  17. Electron acceleration from rest to GeV energy by chirped axicon Gaussian laser pulse in vacuum in the presence of wiggler magnetic field

    Science.gov (United States)

    Kant, Niti; Rajput, Jyoti; Singh, Arvinder

    2018-03-01

    This paper presents a scheme of electron energy enhancement by employing frequency - chirped lowest order axicon focussed radially polarised (RP) laser pulse in vacuum under the influence of wiggler magnetic field. Terawatt RP laser can be focussed down to ∼5μm by an axicon optical element, which produces an intense longitudinal electric field. This unique property of axicon focused Gaussian RP laser pulse is employed for direct electron acceleration in vacuum. A linear frequency chirp increases the time duration of laser-electron interaction, whereas, the applied magnetic wiggler helps in improving the strength of ponderomotive force v→ ×B→ and periodically deflects electron in order to keep it traversing in the accelerating phase up to longer distance. Numerical simulations have been carried out to investigate the influence of laser, frequency chirp and magnetic field parameters on electron energy enhancement. It is noticed that an electron from rest can be accelerated up to GeV energy under optimized laser and magnetic field parameters. Significant enhancement in the electron energy gain of the order of 11.2 GeV is observed with intense chirped laser pulse in the presence of wiggler magnetic field of strength 96.2 kG.

  18. Spin dynamics of electron beams in circular accelerators

    International Nuclear Information System (INIS)

    Boldt, Oliver

    2014-04-01

    Experiments using high energy beams of spin polarized, charged particles still prove to be very helpful in disclosing a deeper understanding of the fundamental structure of matter. An important aspect is to control the beam properties, such as brilliance, intensity, energy, and degree of spin polarization. In this context, the present studies show various numerical calculations of the spin dynamics of high energy electron beams in circular accelerators. Special attention has to be paid to the emission of synchrotron radiation, that occurs when deflecting charged particles on circular orbits. In the presence of the fluctuation of the kinetic energy due to the photon emission, each electron spin moves non-deterministically. This stochastic effect commonly slows down the speed of all numeric estimations. However, the shown simulations cover - using appropriate approximations - trackings for the motion of thousands of electron spins for up to thousands of turns. Those calculations are validated and complemented by empirical investigations at the electron stretcher facility ELSA of the University of Bonn. They can largely be extended to other boundary conditions and thus, can be consulted for new accelerator layouts.

  19. Electron acceleration by electromagnetic irradiation of a weakly-collisional plasma

    International Nuclear Information System (INIS)

    Karfidov, D.M.; Lukina, N.A.; Sergeychev, K.F.

    1989-01-01

    In this paper, electron acceleration is investigated experimentally in both a homogeneous and an inhomogeneous plasma. In the first case acceleration is produced by development of a parametric instability, while in the second case acceleration in a plasma resonance field is used. It is demonstrated that multiple electron passes through a resonant field will produce and accelerated electron energy spectrum characterized by the effective temperature. It is established that the electron replacement current flowing in the interaction region between the plasma and a spatially-limited microwave field excites ion-acoustic turbulence in plasma and also produces an anomalously low thermal conductivity and an anomalously high resistivity

  20. Medium Energy Industrial Electron Beam Accelerator (ILU-EBA) at Navi Mumbai for technology demonstration and commercial operations

    International Nuclear Information System (INIS)

    Benny, P.G.; Khader, S.A.; Sarma, K.S.S.

    2017-01-01

    BARC in early nineties installed a unique high pulse-powered electron beam accelerator of energy 2 MeV, (for the first time in India), in Trombay for developing industrial applications. The accelerator was capable of delivering powered electron beams up to 20kW average beam power (with 1200kW peak pulse power) with energy range from 1 to 2 MeV. Several applications have been developed and commercially exploited in the field of polymer cross linking, degradation, crystalline alterations etc. In addition, applications pertaining to the environmental remediation using electron beams were also worked out. The facility has been relocated at Navi Mumbai a decade ago operated under BARC safety regulatory body and was developed into a technology demonstration cum commercial plant with several product handling gadgets to evaluate the feasibility of different EB treatment processes for the industry viz. waste water treatment, polymer modifications, recycling to name a few

  1. ELECTRON ACCELERATION IN CONTRACTING MAGNETIC ISLANDS DURING SOLAR FLARES

    Energy Technology Data Exchange (ETDEWEB)

    Borovikov, D.; Tenishev, V.; Gombosi, T. I. [University of Michigan, Department of Climate and Space Sciences and Engineering, 2455 Hayward Street, Ann Arbor, MI 48104-2143 (United States); Guidoni, S. E. [The Catholic University of America, 620 Michigan Avenue Northeast, Washington, DC 20064 (United States); DeVore, C. R.; Karpen, J. T.; Antiochos, S. K. [Heliophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)

    2017-01-20

    Electron acceleration in solar flares is well known to be efficient at generating energetic particles that produce the observed bremsstrahlung X-ray spectra. One mechanism proposed to explain the observations is electron acceleration within contracting magnetic islands formed by magnetic reconnection in the flare current sheet. In a previous study, a numerical magnetohydrodynamic simulation of an eruptive solar flare was analyzed to estimate the associated electron acceleration due to island contraction. That analysis used a simple analytical model for the island structure and assumed conservation of the adiabatic invariants of particle motion. In this paper, we perform the first-ever rigorous integration of the guiding-center orbits of electrons in a modeled flare. An initially isotropic distribution of particles is seeded in a contracting island from the simulated eruption, and the subsequent evolution of these particles is followed using guiding-center theory. We find that the distribution function becomes increasingly anisotropic over time as the electrons’ energy increases by up to a factor of five, in general agreement with the previous study. In addition, we show that the energized particles are concentrated on the Sunward side of the island, adjacent to the reconnection X-point in the flare current sheet. Furthermore, our analysis demonstrates that the electron energy gain is dominated by betatron acceleration in the compressed, strengthened magnetic field of the contracting island. Fermi acceleration by the shortened field lines of the island also contributes to the energy gain, but it is less effective than the betatron process.

  2. Neutron yield of medical electron accelerators

    International Nuclear Information System (INIS)

    McCall, R.C.

    1988-01-01

    Shielding calculations for medical electron accelerators above about 10 MeV require some knowledge of the neutron emission from the machine. This knowledge might come from the manufacturer's specifications or from published measurements of the neutron leakage of that particular model and energy of accelerator. In principle, the yield can be calculated if details of the accelerator design are known. These details are often not available because the manufacturer considers them proprietary. A broader knowledge of neutron emission would be useful and it is the purpose of this paper to present such information

  3. The Bonn Electron Stretcher Accelerator ELSA: Past and future

    Energy Technology Data Exchange (ETDEWEB)

    Hillert, W. [Universitaet Bonn, Physikalisches Institut, Bonn (Germany)

    2006-05-15

    In 1953, it was decided to build a 500 MeV electron synchrotron in Bonn. It came into operation 1958, being the first alternating gradient synchrotron in Europe. After five years of performing photoproduction experiments at this accelerator, a larger 2.5 GeV electron synchrotron was built and set into operation in 1967. Both synchrotrons were running for particle physics experiments, until from 1982 to 1987 a third accelerator, the electron stretcher ring ELSA, was constructed and set up in a separate ring tunnel below the physics institute. ELSA came into operation in 1987, using the pulsed 2.5 GeV synchrotron as pre-accelerator. ELSA serves either as storage ring producing synchrotron radiation, or as post-accelerator and pulse stretcher. Applying a slow extraction close to a third integer resonance, external electron beams with energies up to 3.5 GeV and high duty factors are delivered to hadron physics experiments. Various photo- and electroproduction experiments, utilising the experimental set-ups PHOENICS, ELAN, SAPHIR, GDH and Crystal Barrel have been carried out. During the late 90's, a pulsed GaAs source of polarised electrons was constructed and set up at the accelerator. ELSA was upgraded in order to accelerate polarised electrons, compensating for depolarising resonances by applying the methods of fast tune jumping and harmonic closed orbit correction. With the experimental investigation of the GDH sum rule, the first experiment requiring a polarised beam and a polarised target was successfully performed at the accelerator. In the near future, the stretcher ring will be further upgraded to increase polarisation and current of the external electron beams. In addition, the aspects of an increase of the maximum energy to 5 GeV using superconducting resonators will be investigated. (orig.)

  4. The Bonn Electron Stretcher Accelerator ELSA: Past and future

    Science.gov (United States)

    Hillert, W.

    2006-05-01

    In 1953, it was decided to build a 500MeV electron synchrotron in Bonn. It came into operation 1958, being the first alternating gradient synchrotron in Europe. After five years of performing photoproduction experiments at this accelerator, a larger 2.5GeV electron synchrotron was built and set into operation in 1967. Both synchrotrons were running for particle physics experiments, until from 1982 to 1987 a third accelerator, the electron stretcher ring ELSA, was constructed and set up in a separate ring tunnel below the physics institute. ELSA came into operation in 1987, using the pulsed 2.5GeV synchrotron as pre-accelerator. ELSA serves either as storage ring producing synchrotron radiation, or as post-accelerator and pulse stretcher. Applying a slow extraction close to a third integer resonance, external electron beams with energies up to 3.5GeV and high duty factors are delivered to hadron physics experiments. Various photo- and electroproduction experiments, utilising the experimental set-ups PHOENICS, ELAN, SAPHIR, GDH and Crystal Barrel have been carried out. During the late 90's, a pulsed GaAs source of polarised electrons was constructed and set up at the accelerator. ELSA was upgraded in order to accelerate polarised electrons, compensating for depolarising resonances by applying the methods of fast tune jumping and harmonic closed orbit correction. With the experimental investigation of the GDH sum rule, the first experiment requiring a polarised beam and a polarised target was successfully performed at the accelerator. In the near future, the stretcher ring will be further upgraded to increase polarisation and current of the external electron beams. In addition, the aspects of an increase of the maximum energy to 5GeV using superconducting resonators will be investigated.

  5. The Bonn Electron Stretcher Accelerator ELSA: Past and future

    International Nuclear Information System (INIS)

    Hillert, W.

    2006-01-01

    In 1953, it was decided to build a 500 MeV electron synchrotron in Bonn. It came into operation 1958, being the first alternating gradient synchrotron in Europe. After five years of performing photoproduction experiments at this accelerator, a larger 2.5 GeV electron synchrotron was built and set into operation in 1967. Both synchrotrons were running for particle physics experiments, until from 1982 to 1987 a third accelerator, the electron stretcher ring ELSA, was constructed and set up in a separate ring tunnel below the physics institute. ELSA came into operation in 1987, using the pulsed 2.5 GeV synchrotron as pre-accelerator. ELSA serves either as storage ring producing synchrotron radiation, or as post-accelerator and pulse stretcher. Applying a slow extraction close to a third integer resonance, external electron beams with energies up to 3.5 GeV and high duty factors are delivered to hadron physics experiments. Various photo- and electroproduction experiments, utilising the experimental set-ups PHOENICS, ELAN, SAPHIR, GDH and Crystal Barrel have been carried out. During the late 90's, a pulsed GaAs source of polarised electrons was constructed and set up at the accelerator. ELSA was upgraded in order to accelerate polarised electrons, compensating for depolarising resonances by applying the methods of fast tune jumping and harmonic closed orbit correction. With the experimental investigation of the GDH sum rule, the first experiment requiring a polarised beam and a polarised target was successfully performed at the accelerator. In the near future, the stretcher ring will be further upgraded to increase polarisation and current of the external electron beams. In addition, the aspects of an increase of the maximum energy to 5 GeV using superconducting resonators will be investigated. (orig.)

  6. An injector system of a NDZ-20 medical electron linear accelerator

    International Nuclear Information System (INIS)

    Wang Houwen; Lai Qiji; Zhu Yizhang; Yang Fangxin

    1987-01-01

    The structure and characteristic of an injector system of a NDZ-20 medical electron linear accelerator are described. A bombarded type of Pierce electron gun is used. There are pre-focusing coil, deflecting coil, steering coil and beam pulse lead cutting coil in drift tube region. They control electron beam efficiently for ARC, ADC and BLC of the accelerator. ARC and ADC can increase stability and reliability of the accelerator operation, and BLC improves energy spectrum of the back feed accelerator

  7. Injection of electrons by colliding laser pulses in a laser wakefield accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Hansson, M., E-mail: martin.hansson@fysik.lth.se; Aurand, B.; Ekerfelt, H.; Persson, A.; Lundh, O.

    2016-09-01

    To improve the stability and reproducibility of laser wakefield accelerators and to allow for future applications, controlling the injection of electrons is of great importance. This allows us to control the amount of charge in the beams of accelerated electrons and final energy of the electrons. Results are presented from a recent experiment on controlled injection using the scheme of colliding pulses and performed using the Lund multi-terawatt laser. Each laser pulse is split into two parts close to the interaction point. The main pulse is focused on a 2 mm diameter gas jet to drive a nonlinear plasma wave below threshold for self-trapping. The second pulse, containing only a fraction of the total laser energy, is focused to collide with the main pulse in the gas jet under an angle of 150°. Beams of accelerated electrons with low divergence and small energy spread are produced using this set-up. Control over the amount of accelerated charge is achieved by rotating the plane of polarization of the second pulse in relation to the main pulse. Furthermore, the peak energy of the electrons in the beams is controlled by moving the collision point along the optical axis of the main pulse, and thereby changing the acceleration length in the plasma. - Highlights: • Compact colliding pulse injection set-up used to produce low energy spread e-beams. • Beam charge controlled by rotating the polarization of injection pulse. • Peak energy controlled by point of collision to vary the acceleration length.

  8. ELECTRON ACCELERATION BY CASCADING RECONNECTION IN THE SOLAR CORONA. II. RESISTIVE ELECTRIC FIELD EFFECTS

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, X.; Gan, W.; Liu, S. [Key Laboratory of Dark Matter and Space Astronomy, Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008 (China); Büchner, J.; Bárta, M., E-mail: zhou@mps.mpg.de, E-mail: liusm@pmo.ac.cn, E-mail: buechner@mps.mpg.de [Max Planck Institute for Solar System Research, Justus-von-Liebig-Weg 3, D-37077 Göttingen (Germany)

    2016-08-20

    We investigate electron acceleration by electric fields induced by cascading reconnections in current sheets trailing coronal mass ejections via a test particle approach in the framework of the guiding-center approximation. Although the resistive electric field is much weaker than the inductive electric field, the electron acceleration is still dominated by the former. Anomalous resistivity η is switched on only in regions where the current carrier’s drift velocity is large enough. As a consequence, electron acceleration is very sensitive to the spatial distribution of the resistive electric fields, and electrons accelerated in different segments of the current sheet have different characteristics. Due to the geometry of the 2.5-dimensional electromagnetic fields and strong resistive electric field accelerations, accelerated high-energy electrons can be trapped in the corona, precipitating into the chromosphere or escaping into interplanetary space. The trapped and precipitating electrons can reach a few MeV within 1 s and have a very hard energy distribution. Spatial structure of the acceleration sites may also introduce breaks in the electron energy distribution. Most of the interplanetary electrons reach hundreds of keV with a softer distribution. To compare with observations of solar flares and electrons in solar energetic particle events, we derive hard X-ray spectra produced by the trapped and precipitating electrons, fluxes of the precipitating and interplanetary electrons, and electron spatial distributions.

  9. Trends for Electron Beam Accelerator Applications in Industry

    Science.gov (United States)

    Machi, Sueo

    2011-02-01

    Electron beam (EB) accelerators are major pieces of industrial equipment used for many commercial radiation processing applications. The industrial use of EB accelerators has a history of more than 50 years and is still growing in terms of both its economic scale and new applications. Major applications involve the modification of polymeric materials to create value-added products, such as heat-resistant wires, heat-shrinkable sheets, automobile tires, foamed plastics, battery separators and hydrogel wound dressing. The surface curing of coatings and printing inks is a growing application for low energy electron accelerators, resulting in an environmentally friendly and an energy-saving process. Recently there has been the acceptance of the use of EB accelerators in lieu of the radioactive isotope cobalt-60 as a source for sterilizing disposable medical products. Environmental protection by the use of EB accelerators is a new and important field of application. A commercial plant for the cleaning flue gases from a coal-burning power plant is in operation in Poland, employing high power EB accelerators. In Korea, a commercial plant uses EB to clean waste water from a dye factory.

  10. 50 MeV Run of the IOTA / FAST Electron Accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Edstrom Jr., D.; et al.

    2017-02-02

    The low-energy section of the photoinjector-based electron linear accelerator at the Fermilab Accelerator Science & Technology (FAST) facility was recently commissioned to an energy of 50 MeV. This linear accelerator relies primarily upon pulsed SRF acceleration and an optional bunch compressor to produce a stable beam within a large operational regime in terms of bunch charge, total average charge, bunch length, and beam energy. Various instrumentation was used to characterize fundamental properties of the electron beam including the intensity, stability, emittance, and bunch length. While much of this instrumentation was commissioned in a 20 MeV running period prior, some (including a new Martin- Puplett interferometer) was in development or pending installation at that time. All instrumentation has since been recommissioned over the wide operational range of beam energies up to 50 MeV, intensities up to 4 nC/pulse, and bunch structures from ~1 ps to more than 50 ps in length.

  11. Inverse Free Electron Laser accelerator

    International Nuclear Information System (INIS)

    Fisher, A.; Gallardo, J.; van Steenbergen, A.; Sandweiss, J.

    1992-09-01

    The study of the INVERSE FREE ELECTRON LASER, as a potential mode of electron acceleration, is being pursued at Brookhaven National Laboratory. Recent studies have focussed on the development of a low energy, high gradient, multi stage linear accelerator. The elementary ingredients for the IFEL interaction are the 50 MeV Linac e - beam and the 10 11 Watt CO 2 laser beam of BNL's Accelerator Test Facility (ATF), Center for Accelerator Physics (CAP) and a wiggler. The latter element is designed as a fast excitation unit making use of alternating stacks of Vanadium Permendur (VaP) ferromagnetic laminations, periodically interspersed with conductive, nonmagnetic laminations, which act as eddy current induced field reflectors. Wiggler parameters and field distribution data will be presented for a prototype wiggler in a constant period and in a ∼ 1.5 %/cm tapered period configuration. The CO 2 laser beam will be transported through the IFEL interaction region by means of a low loss, dielectric coated, rectangular waveguide. Short waveguide test sections have been constructed and have been tested using a low power cw CO 2 laser. Preliminary results of guide attenuation and mode selectivity will be given, together with a discussion of the optical issues for the IFEL accelerator. The IFEL design is supported by the development and use of 1D and 3D simulation programs. The results of simulation computations, including also wiggler errors, for a single module accelerator and for a multi-module accelerator will be presented

  12. Application of electron accelerator for thin film in Indonesia

    International Nuclear Information System (INIS)

    Danu, Sugiarto; Darsono, Dadang

    2004-01-01

    Electron accelerator is widely used for the crosslinking of wire and cable insulation, the treatment of heat shrinkable products, precuring of tire components, and the sterilization of medical products. Research and development the use of electron accelerator for thin film in Indonesia covered radiation curing of surface coating, crosslinking of poly (butylenes succinate), crosslinking of wire, cable and heat shrinkable, sterilization of wound dressing, and prevulcanization of tire. In general, comparing with conventional method, electron beam processing have some advantages, such as, less energy consumption, much higher production rate, processing ability at ambient temperature and environmental friendly. Indonesia has a great potential to develop the application of electron accelerator, due to the remarkable growth industrial sector, the abundant of natural resources and the increasing demand of the high quality products. This paper describes the activities concerning with R and D, and application of electron accelerator for processing of thin film. (author)

  13. Generation of attosecond electron packets via conical surface plasmon electron acceleration

    Science.gov (United States)

    Greig, S. R.; Elezzabi, A. Y.

    2016-01-01

    We present a method for the generation of high kinetic energy attosecond electron packets via magnetostatic and aperture filtering of conical surface plasmon (SP) accelerated electrons. The conical SP waves are excited by coupling an ultrafast radially polarized laser beam to a conical silica lens coated with an Ag film. Electromagnetic and particle tracking models are employed to characterize the ultrafast electron packets. PMID:26764129

  14. Acceleration of electrons by the wake field of proton bunches

    International Nuclear Information System (INIS)

    Ruggiero, A.G.

    1986-01-01

    This paper discusses a novel idea to accelerate low-intensity bunches of electrons (or positrons) by the wake field of intense proton bunches travelling along the axis of a cylindrical rf structure. Accelerating gradients in excess of 100 MeV/m and large ''transformer ratios'', which allow for acceleration of electrons to energies in the TeV range, are calculated. A possible application of the method is an electron-positron linear collider with luminosity of 10 33 cm -2 s -1 . The relatively low cost and power consumption of the method is emphasized

  15. Development of electron linear accelerators in SAMEER

    International Nuclear Information System (INIS)

    Krishnan, R.

    2015-01-01

    LINear Accelerator (LINAC) based Radiotherapy machine is a key tool for Cancer Treatment. The number of such linac machines available is far less than the actual requirement projected, to suffice the needs of the vast number of Cancer Patients in the country. Development of indigenous state-of-art cancer therapy machine was therefore a crucial achievement under the Jai Vigyan Project of Govt. of India. With the support of Department of Electronics and Information Technology (DeitY), Govt of India, SAMEER has successfully developed 6 MV Radiation Oncology machine at par international standards and is being used to treat cancer patients in the country. SAMEER is also currently developing the dual photon energy and multiple electron energy medical linac machine for radiotherapy and also critical accessories to make a complete oncology system required for advanced state of art treatment. In this paper the work in SAMEER on electron linear accelerators for the medical applications and the related technology and facilities available will be presented. (author)

  16. Beam Position Monitor and Energy Analysis at the Fermilab Accelerator Science and Technology Facility

    Energy Technology Data Exchange (ETDEWEB)

    Lopez, David Juarez [Univ. of Guanajuato (Mexico)

    2015-08-01

    Fermilab Accelerator Science and Technology Facility has produced its first beam with an energy of 20 MeV. This energy is obtained by the acceleration at the Electron Gun and the Capture Cavity 2 (CC2). When fully completed, the accelerator will consist of a photoinjector, one International Liner Collider (ILC)-type cryomodule, multiple accelerator R&D beamlines, and a downstream beamline to inject 300 MeV electrons into the Integrable Optics Test Accelerator (IOTA). We calculated the total energy of the beam and the corresponding energy to the Electron Gun and CC2. Subsequently, a Beam Position Monitors (BPM) error analysis was done, to calculate the device actual resolution.

  17. Novel aspects of direct laser acceleration of relativistic electrons

    Science.gov (United States)

    Arefiev, Alexey

    2015-11-01

    Production of energetic electrons is a keystone aspect of ultraintense laser-plasma interactions that underpins a variety of topics and applications, including fast ignition inertial confinement fusion and compact particle and radiation sources. There is a wide range of electron acceleration regimes that depend on the duration of the laser pulse and the plasma density. This talk focuses on the regime in which the plasma is significantly underdense and the laser pulse duration is longer than the electron response time, so that, in contrast to the wakefield acceleration regime, the pulse creates a quasi-static channel in the electron density. Such a regime is of particular interest, since it can naturally arise in experiments with solid density targets where the pre-pulse of an ultraintense laser produces an extended sub-critical pre-plasma. This talk examines the impact of several key factors on electron acceleration by the laser pulse and the resulting electron energy gain. A detailed consideration is given to the role played by: (1) the static longitudinal electric field, (2) the static transverse electric field, (3) the electron injection into the laser pulse, (4) the electromagnetic dispersion, and (5) the static longitudinal magnetic field. It is shown that all of these factors lead, under conditions outlined in the talk, to a considerable electron energy gain that greatly exceeds the ponderomotive limit. The static fields do not directly transfer substantial energy to electrons. Instead, they alter the longitudinal dephasing between the electrons and the laser pulse, which then allows the electrons to gain extra energy from the pulse. The talk will also outline a time-resolution criterion that must be satisfied in order to correctly reproduce these effects in particle-in-cell simulations. Supported by AFOSR Contract No. FA9550-14-1-0045, National Nuclear Security Administration Contract No. DE-FC52-08NA28512, and US Department of Energy Contract No. DE-FG02

  18. Electron acceleration during the decay of nonlinear Whistler waves in low-beta electron-ion plasma

    International Nuclear Information System (INIS)

    Umeda, Takayuki; Saito, Shinji; Nariyuki, Yasuhiro

    2014-01-01

    Relativistic electron acceleration through dissipation of a nonlinear, short-wavelength, and monochromatic electromagnetic whistler wave in low-beta plasma is investigated by utilizing a one-dimensional fully relativistic electromagnetic particle-in-cell code. The nonlinear (large-amplitude) parent whistler wave decays through the parametric instability which enhances electrostatic ion acoustic waves and electromagnetic whistler waves. These waves satisfy the condition of three-wave coupling. Through the decay instability, the energy of electron bulk velocity supporting the parent wave is converted to the thermal energy perpendicular to the background magnetic field. Increase of the perpendicular temperature triggers the electron temperature anisotropy instability which generates broadband whistler waves and heats electrons in the parallel direction. The broadband whistler waves are inverse-cascaded during the relaxation of the electron temperature anisotropy. In lower-beta conditions, electrons with a pitch angle of about 90° are successively accelerated by inverse-cascaded whistler waves, and selected electrons are accelerated to over a Lorentz factor of 10. The result implies that the nonlinear dissipation of a finite-amplitude and short-wavelength whistler wave plays an important role in producing relativistic nonthermal electrons over a few MeV especially at lower beta plasmas.

  19. Design and construction of the first Iranian powerful industrial electron accelerator

    Directory of Open Access Journals (Sweden)

    AM Poursaleh

    2015-09-01

    Full Text Available In This paper we will introduce the process of design and manufacturing an electron accelerator with 10MeV energy and 100kW power as the first Iranian powerful industrial electron accelerator. This accelerator designed based on modeling of one of the most powerful industrial accelerator called Rhodotron. But the design of the accelerator in a way that can be localize by relying on domestic industries. So although it looks like a Rhodotron accelerator structure but has some different in design and manufacture of components, the results are satisfactory

  20. Parametric study of transport beam lines for electron beams accelerated by laser-plasma interaction

    Science.gov (United States)

    Scisciò, M.; Lancia, L.; Migliorati, M.; Mostacci, A.; Palumbo, L.; Papaphilippou, Y.; Antici, P.

    2016-03-01

    In the last decade, laser-plasma acceleration of high-energy electrons has attracted strong attention in different fields. Electrons with maximum energies in the GeV range can be laser-accelerated within a few cm using multi-hundreds terawatt (TW) lasers, yielding to very high beam currents at the source (electron bunches with up to tens-hundreds of pC in a few fs). While initially the challenge was to increase the maximum achievable electron energy, today strong effort is put in the control and usability of these laser-generated beams that still lack of some features in order to be used for applications where currently conventional, radio-frequency (RF) based, electron beam lines represent the most common and efficient solution. Several improvements have been suggested for this purpose, some of them acting directly on the plasma source, some using beam shaping tools located downstream. Concerning the latter, several studies have suggested the use of conventional accelerator magnetic devices (such as quadrupoles and solenoids) as an easy implementable solution when the laser-plasma accelerated beam requires optimization. In this paper, we report on a parametric study related to the transport of electron beams accelerated by laser-plasma interaction, using conventional accelerator elements and tools. We focus on both, high energy electron beams in the GeV range, as produced on petawatt (PW) class laser systems, and on lower energy electron beams in the hundreds of MeV range, as nowadays routinely obtained on commercially available multi-hundred TW laser systems. For both scenarios, our study allows understanding what are the crucial parameters that enable laser-plasma accelerators to compete with conventional ones and allow for a beam transport. We show that suitable working points require a tradeoff-combination between low beam divergence and narrow energy spread.

  1. Scaling electron acceleration in the bubble regime for upcoming lasers

    International Nuclear Information System (INIS)

    Jansen, O.; Tueckmantel, T.; Pukhov, A.

    2014-01-01

    Electron acceleration in the laser-plasma bubble appeared to be the most successful regime of laser wake field acceleration in the last decade. The laser technology became mature enough to generate short and relativistically intense pulses required to reach the bubble regime naturally delivering quasi-monoenergetic bunches of relativistic electrons. The upcoming laser technology projects are promising short pulses with many times more energy than the existing ones. The natural question is how will the bubble regime scale with the available laser energy. We present here a parametric study of laser-plasma acceleration in the bubble regime using full three dimensional particle-in-cell simulations and compare numerical results with the analytical scalings from the relativistic laser-plasma similarity theory. Our simulations and the theory match almost perfectly for spot sizes above R = 2λ and laser amplitudes above a 0 = 4. We also studied the emission of synchrotron radiation by the accelerated electrons. Both classical and a QED model were applied. We found borders, at which theory and simulations stopped matching. With small spot radii (R < 2λ) we almost never observed the formation of a bubble structure or any form of mono-energetic acceleration. Low laser amplitudes lead to higher energies than predicted by the theory

  2. The Continuous Electron Beam Accelerator Facility

    International Nuclear Information System (INIS)

    Grunder, H.A.; Bisognano, J.J.; Diamond, W.I.; Hartline, B.K.; Leemann, C.W.; Mougey, J.; Sundelin, R.M.; York, R.C.

    1987-01-01

    On February 13, 1987, construction started on the Continuous Electron Beam Accelerator Facility - a 4-GeV, 200-μA, continuous beam, electron accelerator facility designed for nuclear physics research. The machine has a racetrack configuration with two antiparallel, 500-MeV, superconducting linac segments connected by beam lines to allow four passes of recirculation. The accelerating structure consists of 1500-MHz, five-cell niobium cavities developed at Cornell University. A liquid helium cryogenic system cools the cavities to an operating temperature of 2 K. Beam extraction after any three of the four passes allows simultaneous delivery of up to three beams of independently variable currents and different, but correlated, energies to the three experimental areas. Beam breakup thresholds exceed the design current by nearly two orders of magnitude. Project completion and the start of physics operations are scheduled for 1993. The total estimated cost is $255 million

  3. Turbulent acceleration of auroral electrons

    International Nuclear Information System (INIS)

    Bryant, D.A.; Cook, A.C.; Wang, Z.-S.; Angelis, U. de; Perry, C.H.

    1991-07-01

    It is shown that the characteristic peak in the auroral electron velocity distribution can be generated stochastically through resonant interactions with lower-hybrid electrostatic turbulence. The peak itself is shown to be a direct consequence of restrictions imposed on reflexion of electron velocities in the frame of reference of individual wave packets by the limitation in group velocity. A Monte-Carlo model demonstrates how the various properties of the acceleration region are reflected in the resultant electron distribution. It is shown, in particular, that the width of the peak is governed by the amplitude of the turbulence, while the amplitude of the peak reflects the column density of wave energy. Electron distributions encountered within three auroral arcs are interpreted to yield order of magnitude estimates of the amplitude and rms electric field of lower-hybrid wave packets. The velocities and frequencies of the resonant waves, the net electric field, the column density of wave energy and the electric-field energy density are also estimated. The results are found to be consistent with available electric-field measurements. A general broadening of the electron distribution caused by less systematic interactions between electrons and wave packets is shown to have a negligible effect on the peak resulting from the reflexion process; it does, though, lead to the creation of a characteristic high-energy tail. (author)

  4. High-quality electron beam generation in a proton-driven hollow plasma wakefield accelerator

    Science.gov (United States)

    Li, Y.; Xia, G.; Lotov, K. V.; Sosedkin, A. P.; Hanahoe, K.; Mete-Apsimon, O.

    2017-10-01

    Simulations of proton-driven plasma wakefield accelerators have demonstrated substantially higher accelerating gradients compared to conventional accelerators and the viability of accelerating electrons to the energy frontier in a single plasma stage. However, due to the strong intrinsic transverse fields varying both radially and in time, the witness beam quality is still far from suitable for practical application in future colliders. Here we demonstrate the efficient acceleration of electrons in proton-driven wakefields in a hollow plasma channel. In this regime, the witness bunch is positioned in the region with a strong accelerating field, free from plasma electrons and ions. We show that the electron beam carrying the charge of about 10% of 1 TeV proton driver charge can be accelerated to 0.6 TeV with a preserved normalized emittance in a single channel of 700 m. This high-quality and high-charge beam may pave the way for the development of future plasma-based energy frontier colliders.

  5. Low energy accelerators for research and applications

    International Nuclear Information System (INIS)

    Bhandari, R.K.

    2013-01-01

    Charged particle accelerators are instruments for producing a variety of radiations under controlled conditions for basic and applied research as well as applications. They have helped enormously to study the matter, atoms, nuclei, sub-nuclear particles and their constituents, forces involved in the related phenomena etc. No other man-made instrument has been so effective in such studies as the accelerator. The large accelerator constructed so far is the Large Hadron Collider (LHC) housed in a tunnel of 27 km circumference, while a small accelerator can fit inside a room. Small accelerators accelerate charged particles such as electrons, protons, deuterons, alphas and, in general ions to low energy, generally, below several MeV. These particle beams are used for studies in nuclear astrophysics, atomic physics, material science, surface physics, bio sciences etc. They are used for ion beam analysis such as RBS, PIXE, NRA, AMS, CPAA etc. More importantly, the ion beams have important industrial applications like ion implantation, surface modification, isotope production etc. while electron beams are used for material processing, material modification, sterilization, food preservation, non destructive testing etc. In this talk, role of low energy accelerators in research and industry as well as medicine will be discussed. (author)

  6. The acceleration of electrons at a spherical coronal shock in a streamer-like coronal field

    Energy Technology Data Exchange (ETDEWEB)

    Kong, Xiangliang, E-mail: kongx@sdu.edu.cn; Chen, Yao, E-mail: yaochen@sdu.edu.cn [Shandong Provincial Key Laboratory of Optical Astronomy and Solar-Terrestrial Environment, and Institute of Space Sciences, Shandong University, Weihai, Shandong 264209 (China); Guo, Fan, E-mail: guofan.ustc@gmail.com [Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

    2016-03-25

    We study the effect of large-scale coronal magnetic field on the electron acceleration at a spherical coronal shock using a test-particle method. The coronal field is approximated by an analytical solution with a streamer-like magnetic field featured by partially open magnetic field and a current sheet at the equator atop the closed region. It shows that the closed field plays the role of a trapping agency of shock-accelerated electrons, allowing for repetitive reflection and acceleration, therefore can greatly enhance the shock-electron acceleration efficiency. It is found that, with an ad hoc pitch-angle scattering, electron injected in the open field at the shock flank can be accelerated to high energies as well. In addition, if the shock is faster or stronger, a relatively harder electron energy spectrum and a larger maximum energy can be achieved.

  7. Outline of FNCA project on application of electron accelerator

    International Nuclear Information System (INIS)

    Kume, Tamikazu

    2005-01-01

    FNCA (Forum for Nuclear Cooperation in Asia) activities in the field of electron accelerator applications are reported. The paper mainly reports on the achievement of the 3rd workshop to discuss status of utilization of electron accelerator for thin films/hydrogel in the FNCA participating countries, China, Indonesia, Japan, Korea, Malaysia, Philippines, Thailand, and Vietnam, held in August, 2003, at Kuala Lumpur. Cross-linking of thin film from sago starch polymer blend using the Cureton (200 keV, 20 mA) and cross-linking of hydrogel for wound dressing and CMC paste-like sheet using the medium energy (3.0 MeV, 30 mA) electron accelerator of MINT (from Malaysia) were successfully demonstrated. Efforts are being made by Vietnam, Thailand and Philippines having no electron accelerator to acquire the machine for R and D and commercial use in the near future. (S. Ohno)

  8. Electron accelerators and nanomaterials - a symbiosis

    International Nuclear Information System (INIS)

    Dixit, Kavita P.; Mittal, K.C.

    2011-01-01

    Electron Accelerators and Nanomaterials share a symbiotic relationship. While electron accelerators are fast emerging as popular tools in the field of nanomaterials, use of nanomaterials so developed for sub-systems of accelerators is being explored. Material damage studies, surface modification and lithography in the nanometre scale are some of the areas in which electron accelerators are being extensively used. New methods to characterize the structure of nanoparticles use intense X-ray sources, generated from electron accelerators. Enhancement of field emission properties of carbon nanotubes using electron accelerators is another important area that is being investigated. Research on nanomaterials for use in the field of accelerators is still in the laboratory stage. Yet, new trends and emerging technologies can effectively produce materials which can be of significant use in accelerators. Properties such as enhanced field emission can be put to use in cathodes of electron guns. Superconducting properties some materials may also be useful in accelerators. This paper focusses on the electron accelerators used for synthesis, characterization and property-enhancement of nanomaterials. The details of electron accelerators used for these applications will be highlighted. Some light will be thrown on properties of nano materials which can have potential use in accelerators. (author)

  9. New initiatives for producing high current electron accelerators

    International Nuclear Information System (INIS)

    Faehl, R.J.; Keinigs, R.K.; Pogue, E.W.

    1996-01-01

    New classes of compact electron accelerators able to deliver multi-kiloamperes of pulsed 10-50 MeV electron beams are being studied. One class is based upon rf linac technology with dielectric-filled cavities. For materials with ε/ε o >>1, the greatly increased energy storage permits high current operation. The second type is a high energy injected betatron. Circulating current limits scale as Β 2 γ 3

  10. Electron acceleration by a radially polarized laser pulse during ionization of low density gases

    Directory of Open Access Journals (Sweden)

    Kunwar Pal Singh

    2011-03-01

    Full Text Available The acceleration of electrons by a radially polarized intense laser pulse has been studied. The axial electric field of the laser is responsible for electron acceleration. The axial electric field increases with decreasing laser spot size; however, the laser pulse gets defocused sooner for smaller values and the electrons do not experience high electric field for long, reducing the energy they can reach. The electron remains confined in the electric field of the laser for longer and the electron energy peaks for the normalized laser spot size nearly equal to the normalized laser intensity parameter. Electron energy peaks for initial laser phase ϕ_{0}=π due to accelerating laser phase and decreases with transverse initial position of the electrons. The energy and angle of the emittance spectrum of the electrons generated during ionization of krypton and argon at low densities have been obtained and a right choice of laser parameters has been suggested to obtain high energy quasimonoenergetic collimated electron beams. It has been found that argon is more suitable than krypton to obtain high energy electron beams due to higher ionization potential of inner shells for the former.

  11. Measurement of Electron Clouds in Large Accelerators by Microwave Dispersion

    Energy Technology Data Exchange (ETDEWEB)

    De Santis, S.; Byrd, J.M.; /LBL, Berkeley; Caspers, F.; /CERN; Krasnykh, A.; /SLAC; Kroyer, T.; /CERN; Pivi, M.T.F.; /SLAC; Sonnad, K.G.; /LBL, Berkeley

    2008-03-19

    Clouds of low energy electrons in the vacuum beam pipes of accelerators of positively charged particle beams present a serious limitation for operation at high currents. Furthermore, it is difficult to probe their density over substantial lengths of the beam pipe. We have developed a novel technique to directly measure the electron cloud density via the phase shift induced in a TE wave transmitted over a section of the accelerator and used it to measure the average electron cloud density over a 50 m section in the positron ring of the PEP-II collider at the Stanford Linear Accelerator Center.

  12. Low energy intense electron beams with extra-low energy spread

    International Nuclear Information System (INIS)

    Aleksandrov, A.V.; Calabrese, R.; Ciullo, G.; Dikansky, N.S.; Guidi, V.; Kot, N.C.; Kudelainen, V.I.; Lamanna, G.; Lebedev, V.A.; Logachov, P.V.; Tecchio, L.; Yang, B.

    1994-01-01

    Maximum achievable intensity for low energy electron beams is a feature that is not very often compatible with low energy spread. We show that a proper choice of the source and the acceleration optics allows one to match them together. In this scheme, a GaAs photocathode excited by a single-mode infrared laser and adiabatic acceleration in fully magnetised optics enables the production of a low-energy-spread electron beam with relatively high intensity. The technological problems associated with the method are discussed together with its limitations. (orig.)

  13. Staging laser plasma accelerators for increased beam energy

    International Nuclear Information System (INIS)

    Panasenko, Dmitriy; Shu, Anthony; Schroeder, Carl; Gonsalves, Anthony; Nakamura, Kei; Matlis, Nicholas; Cormier-Michel, Estelle; Plateau, Guillaume; Lin, Chen; Toth, Csaba; Geddes, Cameron; Esarey, Eric; Leemans, Wim

    2008-01-01

    Staging laser plasma accelerators is an efficient way of mitigating laser pump depletion in laser driven accelerators and necessary for reaching high energies with compact laser systems. The concept of staging includes coupling of additional laser energy and transporting the electron beam from one accelerating module to another. Due to laser damage threshold constraints, in-coupling laser energy with conventional optics requires distances between the accelerating modules of the order of 10m, resulting in decreased average accelerating gradient and complicated e-beam transport. In this paper we use basic scaling laws to show that the total length of future laser plasma accelerators will be determined by staging technology. We also propose using a liquid jet plasma mirror for in-coupling the laser beam and show that it has the potential to reduce distance between stages to the cm-scale.

  14. Investigations of electron beams from a linear accelerator

    International Nuclear Information System (INIS)

    Sweeney, L.E.

    1981-01-01

    The use of high energy electron beams from linear accelerators is becoming more prevalent in Radiation Therapy clinics. Although the basic interactions of electrons in material have been described for many years, the use of the high energy electron beams is based mostly upon measurements in the clinical setting. It is the purpose of this work to experimentally study the physical properties and apply basic concepts to analyze these measurements. Three different topics are addressed in this work. The distance to the virtual source of the electron beam is determined by a series of ionization measurements in air and in a plastic phantom as a function of distance from the accelerator. Scattering effects of the x-ray collimators and electron applicators play an important role in the clinical evaluation of the distance to the virtual source as well as the energy of the electron beam. The ionization distribution of a narrow beam of 21 MeV electrons is measured and compared to theoretical calculations. The transverse ionization distribution is measured in a water phantom and compared with Monte Carlo calculation for this energy. The depth dose distribution is measured in two distinct geometrical configurations and found to be analogous within the errors of measurement. Depth ionization and depth dose properties of a broad 21 MeV electron beam are determined for a number of homogeneous materials having different physical properties. Comparison of these measurements are described by two different scaling factors for polystyrene, water, teflon, and aluminum phantom materials. Basic physical interactions, experimental techniques and results are discussed

  15. Electron beam accelerator: A new tool for environmental preservation in Malaysia

    Science.gov (United States)

    Hashim, Siti Aiasah; Bakar, Khomsaton Abu; Othman, Mohd Nahar

    2012-09-01

    Electron beam accelerators are widely used for industrial applications such as surface curing, crosslinking of wires and cables and sterilization/ decontamination of pharmaceutical products. The energy of the electron beam determines the type of applications. This is due to the penetration power of the electron that is limited by the energy. In the last decade, more work has been carried out to utilize the energetic electron for remediation of environmental pollution. For this purposes, 1 MeV electron beam accelerator is sufficient to treat wastewater from textile industry and flue gases from fossil fuel combustions. In Nuclear Malaysia, a variable energy Cockroft Walton type accelerator has been utilized to initiate investigations in these two areas. An electron beam flue gas treatment test rig was built to treat emission from diesel combustion, where it was found that using EB parameters of 1MeV and 12mA can successfully remove at least 80% of nitric oxide in the emission. Wastewater from textile industries was treated using combination of biological treatment and EB. The initial findings indicated that the quality of water had improved based on the CODCr, BOD5 indicators.

  16. Electron beam accelerator: A new tool for environmental preservation in Malaysia

    International Nuclear Information System (INIS)

    Hashim, Siti Aiasah; Bakar, Khomsaton Abu; Othman, Mohd Nahar

    2012-01-01

    Electron beam accelerators are widely used for industrial applications such as surface curing, crosslinking of wires and cables and sterilization/ decontamination of pharmaceutical products. The energy of the electron beam determines the type of applications. This is due to the penetration power of the electron that is limited by the energy. In the last decade, more work has been carried out to utilize the energetic electron for remediation of environmental pollution. For this purposes, 1 MeV electron beam accelerator is sufficient to treat wastewater from textile industry and flue gases from fossil fuel combustions. In Nuclear Malaysia, a variable energy Cockroft Walton type accelerator has been utilized to initiate investigations in these two areas. An electron beam flue gas treatment test rig was built to treat emission from diesel combustion, where it was found that using EB parameters of 1MeV and 12mA can successfully remove at least 80% of nitric oxide in the emission. Wastewater from textile industries was treated using combination of biological treatment and EB. The initial findings indicated that the quality of water had improved based on the COD Cr , BOD 5 indicators.

  17. 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

  18. Production and applications of quasi-monoenergetic electron bunches in laser-plasma based accelerators

    International Nuclear Information System (INIS)

    Glinec, Y.; Faure, J.; Ewald, F.; Lifschitz, A.; Malka, V.

    2006-01-01

    Plasmas are attractive media for the next generation of compact particle accelerators because they can sustain electric fields larger than those in conventional accelerators by three orders of magnitude. However, until now, plasma-based accelerators have produced relatively poor quality electron beams even though for most practical applications, high quality beams are required. In particular, beams from laser plasma-based accelerators tend to have a large divergence and very large energy spreads, meaning that different particles travel at different speeds. The combination of these two problems makes it difficult to utilize these beams. Here, we demonstrate the production of high quality and high energy electron beams from laser-plasma interaction: in a distance of 3 mm, a very collimated and quasi-monoenergetic electron beam is emitted with a 0.5 nanocoulomb charge at 170 ± 20 MeV. In this regime, we have observed very nonlinear phenomena, such as self-focusing and temporal self-shortenning down to 10 fs durations. Both phenomena increase the excitation of the wakefield. The laser pulse drives a highly nonlinear wakefield, able to trap and accelerate plasma background electrons to a single energy. We will review the different regimes of electron acceleration and we will show how enhanced performances can be reached with state-of-the-art ultrashort laser systems. Applications such as gamma radiography of such electron beams will also be discussed

  19. A parametric model to describe neutron spectra around high-energy electron accelerators and its application in neutron spectrometry with Bonner Spheres

    Science.gov (United States)

    Bedogni, Roberto; Pelliccioni, Maurizio; Esposito, Adolfo

    2010-03-01

    Due to the increased interest of the scientific community in the applications of synchrotron light, there is an increasing demand of high-energy electron facilities, testified by the construction of several new facilities worldwide. The radiation protection around such facilities requires accurate experimental methods to determine the dose due to prompt radiation fields. Neutron fields, in particular, are the most complex to measure, because they extend in energy from thermal (10 -8 MeV) up to hundreds MeV and because the responses of dosemeters and survey meters usually have large energy dependence. The Bonner Spheres Spectrometer (BSS) is in practice the only instrument able to respond over the whole energy range of interest, and for this reason it is frequently used to derive neutron spectra and dosimetric quantities in accelerator workplaces. Nevertheless, complex unfolding algorithms are needed to derive the neutron spectra from the experimental BSS data. This paper presents a parametric model specially developed for the unfolding of the experimental data measured with BSS around high-energy electron accelerators. The work consists of the following stages: (1) Generation with the FLUKA code, of a set of neutron spectra representing the radiation environment around accelerators with different electron energies; (2) formulation of a parametric model able to describe these spectra, with particular attention to the high-energy component (>10 MeV), which may be responsible for a large part of the dose in workplaces; and (3) implementation of this model in an existing unfolding code.

  20. A parametric model to describe neutron spectra around high-energy electron accelerators and its application in neutron spectrometry with Bonner Spheres

    International Nuclear Information System (INIS)

    Bedogni, Roberto; Pelliccioni, Maurizio; Esposito, Adolfo

    2010-01-01

    Due to the increased interest of the scientific community in the applications of synchrotron light, there is an increasing demand of high-energy electron facilities, testified by the construction of several new facilities worldwide. The radiation protection around such facilities requires accurate experimental methods to determine the dose due to prompt radiation fields. Neutron fields, in particular, are the most complex to measure, because they extend in energy from thermal (10 -8 MeV) up to hundreds MeV and because the responses of dosemeters and survey meters usually have large energy dependence. The Bonner Spheres Spectrometer (BSS) is in practice the only instrument able to respond over the whole energy range of interest, and for this reason it is frequently used to derive neutron spectra and dosimetric quantities in accelerator workplaces. Nevertheless, complex unfolding algorithms are needed to derive the neutron spectra from the experimental BSS data. This paper presents a parametric model specially developed for the unfolding of the experimental data measured with BSS around high-energy electron accelerators. The work consists of the following stages: (1) Generation with the FLUKA code, of a set of neutron spectra representing the radiation environment around accelerators with different electron energies; (2) formulation of a parametric model able to describe these spectra, with particular attention to the high-energy component (>10 MeV), which may be responsible for a large part of the dose in workplaces; and (3) implementation of this model in an existing unfolding code.

  1. Non-thermal particle acceleration in collisionless relativistic electron-proton reconnection

    Science.gov (United States)

    Werner, G. R.; Uzdensky, D. A.; Begelman, M. C.; Cerutti, B.; Nalewajko, K.

    2018-02-01

    Magnetic reconnection in relativistic collisionless plasmas can accelerate particles and power high-energy emission in various astrophysical systems. Whereas most previous studies focused on relativistic reconnection in pair plasmas, less attention has been paid to electron-ion plasma reconnection, expected in black hole accretion flows and relativistic jets. We report a comprehensive particle-in-cell numerical investigation of reconnection in an electron-ion plasma, spanning a wide range of ambient ion magnetizations σi, from the semirelativistic regime (ultrarelativistic electrons but non-relativistic ions, 10-3 ≪ σi ≪ 1) to the fully relativistic regime (both species are ultrarelativistic, σi ≫ 1). We investigate how the reconnection rate, electron and ion plasma flows, electric and magnetic field structures, electron/ion energy partitioning, and non-thermal particle acceleration depend on σi. Our key findings are: (1) the reconnection rate is about 0.1 of the Alfvénic rate across all regimes; (2) electrons can form concentrated moderately relativistic outflows even in the semirelativistic, small-σi regime; (3) while the released magnetic energy is partitioned equally between electrons and ions in the ultrarelativistic limit, the electron energy fraction declines gradually with decreased σi and asymptotes to about 0.25 in the semirelativistic regime; and (4) reconnection leads to efficient non-thermal electron acceleration with a σi-dependent power-law index, p(σ _i)˜eq const+0.7σ _i^{-1/2}. These findings are important for understanding black hole systems and lend support to semirelativistic reconnection models for powering non-thermal emission in blazar jets, offering a natural explanation for the spectral indices observed in these systems.

  2. Simultaneous analysis with respect to time and energy of a linear electron accelerator beam; Analyse simultanee en temps et en energie du faisceau d'un accelerateur lineaire d'electrons

    Energy Technology Data Exchange (ETDEWEB)

    Garganne, P [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1965-07-01

    A system is described for displaying on an oscilloscope screen the energy spectrum of the electrons located in time at a particular moment of the total electron pulse accelerated by a linac. The shaping transistor circuitry is particularly described. Some examples are given concerning the experimental results observed with such a system at the Saclay Linac. (author) [French] On decrit un systeme d'affichage sur un ecran d'oscilloscope, du spectre en energie des electrons sortant de l'accelerateur a un instant variable dans l'impulsion totale acceleree, insistant sur les circuits a transistors de mise en forme des impulsions. On donne quelques exemples de resultats obtenus sur l'accelerateur lineaire de Saclay. (auteur)

  3. Tesla-transformer-type electron beam accelerator

    International Nuclear Information System (INIS)

    Liu Jinliang; Zhong Huihuang; Tan Qimei; Li Chuanlu; Zhang Jiande

    2002-01-01

    An electron-beam Tesla-transformer accelerator is described. It consists of the primary storage energy system. Tesla transformer, oil Blumlein pulse form line, and the vacuum diode. The experiments of initial stage showed that diode voltage rises up to about 500 kV with an input of 20 kV and the maximum electron-beam current is about 9 kA, the pulse width is about 50 ns. This device can operate stably and be set up easily

  4. Electron acceleration by wave turbulence in a magnetized plasma

    Science.gov (United States)

    Rigby, A.; Cruz, F.; Albertazzi, B.; Bamford, R.; Bell, A. R.; Cross, J. E.; Fraschetti, F.; Graham, P.; Hara, Y.; Kozlowski, P. M.; Kuramitsu, Y.; Lamb, D. Q.; Lebedev, S.; Marques, J. R.; Miniati, F.; Morita, T.; Oliver, M.; Reville, B.; Sakawa, Y.; Sarkar, S.; Spindloe, C.; Trines, R.; Tzeferacos, P.; Silva, L. O.; Bingham, R.; Koenig, M.; Gregori, G.

    2018-05-01

    Astrophysical shocks are commonly revealed by the non-thermal emission of energetic electrons accelerated in situ1-3. Strong shocks are expected to accelerate particles to very high energies4-6; however, they require a source of particles with velocities fast enough to permit multiple shock crossings. While the resulting diffusive shock acceleration4 process can account for observations, the kinetic physics regulating the continuous injection of non-thermal particles is not well understood. Indeed, this injection problem is particularly acute for electrons, which rely on high-frequency plasma fluctuations to raise them above the thermal pool7,8. Here we show, using laboratory laser-produced shock experiments, that, in the presence of a strong magnetic field, significant electron pre-heating is achieved. We demonstrate that the key mechanism in producing these energetic electrons is through the generation of lower-hybrid turbulence via shock-reflected ions. Our experimental results are analogous to many astrophysical systems, including the interaction of a comet with the solar wind9, a setting where electron acceleration via lower-hybrid waves is possible.

  5. Spatially inhomogeneous acceleration of electrons in solar flares

    Science.gov (United States)

    Stackhouse, Duncan J.; Kontar, Eduard P.

    2018-04-01

    The imaging spectroscopy capabilities of the Reuven Ramaty high energy solar spectroscopic imager (RHESSI) enable the examination of the accelerated electron distribution throughout a solar flare region. In particular, it has been revealed that the energisation of these particles takes place over a region of finite size, sometimes resolved by RHESSI observations. In this paper, we present, for the first time, a spatially distributed acceleration model and investigate the role of inhomogeneous acceleration on the observed X-ray emission properties. We have modelled transport explicitly examining scatter-free and diffusive transport within the acceleration region and compare with the analytic leaky-box solution. The results show the importance of including this spatial variation when modelling electron acceleration in solar flares. The presence of an inhomogeneous, extended acceleration region produces a spectral index that is, in most cases, different from the simple leaky-box prediction. In particular, it results in a generally softer spectral index than predicted by the leaky-box solution, for both scatter-free and diffusive transport, and thus should be taken into account when modelling stochastic acceleration in solar flares.

  6. Acceleration of electrons and supplementary ionization during parametrical plasma heating

    International Nuclear Information System (INIS)

    Grach, S.M.; Mityakov, N.A.; Trakhtengerts, V.Yu.; AN SSSR, Gor'kij. Inst. Prikladnoj Fiziki)

    1986-01-01

    Acceleration of electrons by plasma waves in partially ionized plasma is considered with provision for the effects of turbulent scattering and formation of secondary electrons, which are produced in the process of electron shock ionization. It is shown that the avalanche density growth of electrons accelerated up to 1-2 ionization potential (instability) takes place beginning from some critical density of plasma waves. Density of fast electrons is found out along with plasma wave energy density at the stage of instability saturation. Additional concentration of a background plasma, which manifests itself due to ionization, is evaluated

  7. Study of loading by beam of dual-resonator structure of linear electron accelerator

    International Nuclear Information System (INIS)

    Milovanov, O.S.; Smirnov, I.A.

    1988-01-01

    Loading by the beam of the accelerating structure of an Argus dual-resonator linear electron accelerator with a kinetic energy of ∼ 1 MeV and a pulsed beam current of up to 0.5 A is studied experimentally. It is shown that the conditions for stable single-frequency operation of the magnetron are disrupted and the acceleration process is cut off at certain electron-beam currents. Experimental curves of the maximum beam current and maximum electron efficiency of the Argus linear electron accelerator as functions of rf power are given

  8. Energy Balance in an Electrostatic Accelerator

    OpenAIRE

    Zolotorev, Max S.; McDonald, Kirk T.

    2000-01-01

    The principle of an electrostatic accelerator is that when a charge e escapes from a conducting plane that supports a uniform electric field of strength E_0, then the charge gains energy e E_0 d as it moves distance d from the plane. Where does this energy come from? We that the mechanical energy gain of the electron is balanced by the decrease in the electrostatic field energy of the system.

  9. High-Energy Electron Beam Application to Air Pollutants Removal

    International Nuclear Information System (INIS)

    Ighigeanu, D.; Martin, D.; Manaila, E.; Craciun, G.; Calinescu, I.

    2009-01-01

    The advantage of electron beam (EB) process in pollutants removal is connected to its high efficiency to transfer high amount of energy directly into the matter under treatment. Disadvantage which is mostly related to high investment cost of accelerator may be effectively overcome in future as the result of use accelerator new developments. The potential use of medium to high-energy high power EB accelerators for air pollutants removal is demonstrated in [1]. The lower electrical efficiencies of accelerators with higher energies are partially compensated by the lower electron energy losses in the beam windows. In addition, accelerators with higher electron energies can provide higher beam powers with lower beam currents [1]. The total EB energy losses (backscattering, windows and in the intervening air space) are substantially lower with higher EB incident energy. The useful EB energy is under 50% for 0.5 MeV and about 95% above 3 MeV. In view of these arguments we decided to study the application of high energy EB for air pollutants removal. Two electron beam accelerators are available for our studies: electron linear accelerators ALIN-10 and ALID-7, built in the Electron Accelerator Laboratory, INFLPR, Bucharest, Romania. Both accelerators are of traveling-wave type, operating at a wavelength of 10 cm. They utilize tunable S-band magnetrons, EEV M 5125 type, delivering 2 MW of power in 4 μ pulses. The accelerating structure is a disk-loaded tube operating in the 2 mode. The optimum values of the EB peak current IEB and EB energy EEB to produce maximum output power PEB for a fixed pulse duration EB and repetition frequency fEB are as follows: for ALIN-10: EEB = 6.23 MeV; IEB =75 mA; PEB 164 W (fEB = 100 Hz, EB = 3.5 s) and for ALID-7: EEB 5.5 MeV; IEB = 130 mA; PEB = 670 W (fEB = 250 Hz, EB = 3.75 s). This paper presents a special designed installation, named SDI-1, and several representative results obtained by high energy EB application to SO 2 , NOx and VOCs

  10. Collective ion acceleration by relativistic electron beams in plasmas

    International Nuclear Information System (INIS)

    Galvez, M.; Gisler, G.

    1991-01-01

    A two-dimensional fully electromagnetic particle-in-cell code is used to simulate the interaction of a relativistic electron beam injected into a finite-size background neutral plasma. The simulations show that the background electrons are pushed away from the beam path, forming a neutralizing ion channel. Soon after the beam head leaves the plasma, a virtual cathode forms which travels away with the beam. However, at later times a second, quasi-stationary, virtual cathode forms. Its position and strength depends critically on the parameters of the system which critically determines the efficiency of the ion acceleration process. The background ions trapped in the electrostatic well of the virtual cathode are accelerated and at later times, the ions as well as the virtual cathode drift away from the plasma region. The surfing of the ions in the electrostatic well produces an ion population with energies several times the initial electron beam energy. It is found that optimum ion acceleration occurs when the beam-to-plasma density ratio is near unity. When the plasma is dense, the beam is a weak perturbation and accelerates few ions, while when the plasma is tenuous, the beam is not effectively neutralized, and a virtual cathode occurs right at the injection plane. The simulations also show that, at the virtual cathode position, the electron beam is pinched producing a self-focusing phenomena

  11. Properties of the electron cloud in a high-energy positron and electron storage ring

    International Nuclear Information System (INIS)

    Harkay, K.C.; Rosenberg, R.A.

    2003-01-01

    Low-energy, background electrons are ubiquitous in high-energy particle accelerators. Under certain conditions, interactions between this electron cloud and the high-energy beam can give rise to numerous effects that can seriously degrade the accelerator performance. These effects range from vacuum degradation to collective beam instabilities and emittance blowup. Although electron-cloud effects were first observed two decades ago in a few proton storage rings, they have in recent years been widely observed and intensely studied in positron and proton rings. Electron-cloud diagnostics developed at the Advanced Photon Source enabled for the first time detailed, direct characterization of the electron-cloud properties in a positron and electron storage ring. From in situ measurements of the electron flux and energy distribution at the vacuum chamber wall, electron-cloud production mechanisms and details of the beam-cloud interaction can be inferred. A significant longitudinal variation of the electron cloud is also observed, due primarily to geometrical details of the vacuum chamber. Such experimental data can be used to provide realistic limits on key input parameters in modeling efforts, leading ultimately to greater confidence in predicting electron-cloud effects in future accelerators.

  12. Perturbation of the energy loss spectra for an accelerated electron beam due to the photo injector exit

    CERN Document Server

    Salah, W

    2003-01-01

    The influence of the photo-injector exit hall on the energy loss for an accelerated electron beam is investigated, by calculating the total energy transferred from the electrons to the wakefields, which are driven by the beam. The obtained energy loss is compared to those previously obtained for a 'pill-box' cavity. This comparison shows that the influence of this hall, in terms of energy loss, varies over the beam length. It is strongest in the middle of the beam and decreases towards both ends. In consequence of this perturbation, the center of the beam is displaced from its initial position during the first phase (t < 200 ps) where the exit aperture has no effect to a new equilibrium position which takes place at 200 < t < 250 ps. (author)

  13. Mount Aragats as a stable electron accelerator for atmospheric High-energy physics research

    International Nuclear Information System (INIS)

    Chilingarian, A.; Hovsepyan, G.; Mnatsakanyan, E.

    2016-01-01

    The observation of the numerous Thunderstorm ground Enhancements (TGEs), i.e. enhanced fluxes of electrons, gamma rays and neutrons detected by particle detectors located on the Earth’s surface and related to the strong thunderstorms above it helped to establish a new scientific topic - high-energy physics in the atmosphere. The Relativistic Runaway Electron Avalanches (RREAs) are believed to be a central engine initiated high-energy processes in the thunderstorm atmospheres. RREAs observed on Aragats Mt. in Armenia during strongest thunderstorms and simultaneous measurements of TGE electron and gamma ray energy spectra proved that RREA is a robust and realistic mechanism for electron acceleration. TGE research facilitates investigations of the long-standing lightning initiation problem. For the last 5 years we were experimenting with the “beams” of “electron accelerators” operated in the thunderclouds above the Aragats research station. Thunderstorms are very frequent above Aragats, peaking at May-June and almost all of them are accompanied with enhanced particle fluxes. The station is located on a plateau at altitude 3200 asl near a large lake. Numerous particle detectors and field meters are located in three experimental halls as well as outdoors; the facilities are operated all year round. The key method employed is that all the relevant information is being gathered, including the data on the particle fluxes, fields, lightning occurrences, and meteorological conditions. By the example of the huge thunderstorm that took place at Mt. Aragats on the 28th of August 2015, we show that simultaneous detection of all the relevant data allowed us to reveal the temporal pattern of the storm development and to investigate the atmospheric discharges and particle fluxes. (author)

  14. Development and applications of super high energy collider accelerators. Vol. 1

    Energy Technology Data Exchange (ETDEWEB)

    Abdelaziz, E M [National Center for Nuclear Safety and Radiation Control, Atomic Energy Authority, Cairo, (Egypt)

    1996-03-01

    This paper presents a review of cyclic accelerators and their energy limitations. A description is given of the phase stability principle and evaluation of the synchrotron, an accelerator without energy limitation. Then the concept of colliding beams emerged to yield doubling of the beam energy as in the Tevatron 2 trillion electron volts (TeV) proton collider at Fermilab, and the large harden collider (LHD) which is now planned as a 14-TeV machine in the 27 Kilometer tunnel of the large electron positron (LEP) collider at CERN. Then presentation is given of the superconducting supercollider (SSC), a giant accelerator complex with energy 40-TeV in a tunnel 87 Kilometers in circumference under the country surrounding Waxahachile in Texas, U.S.A. These superhigh energy accelerators are intended to smash protons against protons at energy sufficient to reveal the nature of matter and to consolidate the prevailing general theory of elementary particles. 12 figs., 1 tab.

  15. Development and applications of super high energy collider accelerators. Vol. 1

    International Nuclear Information System (INIS)

    Abdelaziz, E.M.

    1996-01-01

    This paper presents a review of cyclic accelerators and their energy limitations. A description is given of the phase stability principle and evaluation of the synchrotron, an accelerator without energy limitation. Then the concept of colliding beams emerged to yield doubling of the beam energy as in the Tevatron 2 trillion electron volts (TeV) proton collider at Fermilab, and the large harden collider (LHD) which is now planned as a 14-TeV machine in the 27 Kilometer tunnel of the large electron positron (LEP) collider at CERN. Then presentation is given of the superconducting supercollider (SSC), a giant accelerator complex with energy 40-TeV in a tunnel 87 Kilometers in circumference under the country surrounding Waxahachile in Texas, U.S.A. These superhigh energy accelerators are intended to smash protons against protons at energy sufficient to reveal the nature of matter and to consolidate the prevailing general theory of elementary particles. 12 figs., 1 tab

  16. Neutron-induced electronic failures around a high-energy linear accelerator

    International Nuclear Information System (INIS)

    Kry, Stephen F.; Johnson, Jennifer L.; White, R. Allen; Howell, Rebecca M.; Kudchadker, Rajat J.; Gillin, Michael T.

    2011-01-01

    Purpose: After a new in-vault CT-on-rails system repeatedly malfunctioned following use of a high-energy radiotherapy beam, we investigated the presence and impact of neutron radiation on this electronic system, as well as neutron shielding options. Methods: We first determined the CT scanner's failure rate as a function of the number of 18 MV monitor units (MUs) delivered. We then re-examined the failure rate with both 2.7-cm-thick and 7.6-cm-thick borated polyethylene (BPE) covering the linac head for neutron shielding. To further examine shielding options, as well as to explore which neutrons were relevant to the scanner failure, Monte Carlo simulations were used to calculate the neutron fluence and spectrum in the bore of the CT scanner. Simulations included BPE covering the CT scanner itself as well as covering the linac head. Results: We found that the CT scanner had a 57% chance of failure after the delivery of 200 MUs. While the addition of neutron shielding to the accelerator head reduced this risk of failure, the benefit was minimal and even 7.6 cm of BPE was still associated with a 29% chance of failure after the delivery of 200 MU. This shielding benefit was achieved regardless of whether the linac head or CT scanner was shielded. Additionally, it was determined that fast neutrons were primarily responsible for the electronic failures. Conclusions: As illustrated by the CT-on-rails system in the current study, physicists should be aware that electronic systems may be highly sensitive to neutron radiation. Medical physicists should therefore monitor electronic systems that have not been evaluated for potential neutron sensitivity. This is particularly relevant as electronics are increasingly common in the therapy vault and newer electronic systems may exhibit increased sensitivity.

  17. 5 MeV 300 kW electron accelerator project

    International Nuclear Information System (INIS)

    Auslender, V.L.; Cheskidov, V.G.; Gornakov, I.V.

    2004-01-01

    The paper presents a project of a high power linear accelerator for industrial applications. The accelerator has a modular structure and consists of the chain of accelerating cavities connected by the axis-located coupling cavities with coupling slots in the common walls. Main parameters of the accelerator are: operating frequency of 176 MHz, electron energy of up to 5 MeV, average beam power of 300 kW. The required RF pulse power can be supplied by the TH628 diacrode

  18. Inverse free electron laser accelerator for advanced light sources

    Directory of Open Access Journals (Sweden)

    J. P. Duris

    2012-06-01

    Full Text Available We discuss the inverse free electron laser (IFEL scheme as a compact high gradient accelerator solution for driving advanced light sources such as a soft x-ray free electron laser amplifier or an inverse Compton scattering based gamma-ray source. In particular, we present a series of new developments aimed at improving the design of future IFEL accelerators. These include a new procedure to optimize the choice of the undulator tapering, a new concept for prebunching which greatly improves the fraction of trapped particles and the final energy spread, and a self-consistent study of beam loading effects which leads to an energy-efficient high laser-to-beam power conversion.

  19. An in situ Comparison of Electron Acceleration at Collisionless Shocks under Differing Upstream Magnetic Field Orientations

    Energy Technology Data Exchange (ETDEWEB)

    Masters, A.; Dougherty, M. K. [The Blackett Laboratory, Imperial College London, Prince Consort Road, London, SW7 2AZ (United Kingdom); Sulaiman, A. H. [Department of Physics and Astronomy, University of Iowa, Iowa City, IA 52242 (United States); Stawarz, Ł. [Astronomical Observatory, Jagiellonian University, ul. Orla 171, 30-244 Krakow (Poland); Reville, B. [School of Mathematics and Physics, Queens University Belfast, Belfast BT7 1NN (United Kingdom); Sergis, N. [Office of Space Research and Technology, Academy of Athens, Soranou Efesiou 4, 11527 Athens (Greece); Fujimoto, M. [Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Chuo-ku, Sagamihara, Kanagawa 252-5210 (Japan); Burgess, D. [School of Physics and Astronomy, Queen Mary University of London, London E1 4NS (United Kingdom); Coates, A. J., E-mail: a.masters@imperial.ac.uk [Mullard Space Science Laboratory, Department of Space and Climate Physics, University College London, Holmbury St. Mary, Dorking RH5 6NT (United Kingdom)

    2017-07-10

    A leading explanation for the origin of Galactic cosmic rays is acceleration at high-Mach number shock waves in the collisionless plasma surrounding young supernova remnants. Evidence for this is provided by multi-wavelength non-thermal emission thought to be associated with ultrarelativistic electrons at these shocks. However, the dependence of the electron acceleration process on the orientation of the upstream magnetic field with respect to the local normal to the shock front (quasi-parallel/quasi-perpendicular) is debated. Cassini spacecraft observations at Saturn’s bow shock have revealed examples of electron acceleration under quasi-perpendicular conditions, and the first in situ evidence of electron acceleration at a quasi-parallel shock. Here we use Cassini data to make the first comparison between energy spectra of locally accelerated electrons under these differing upstream magnetic field regimes. We present data taken during a quasi-perpendicular shock crossing on 2008 March 8 and during a quasi-parallel shock crossing on 2007 February 3, highlighting that both were associated with electron acceleration to at least MeV energies. The magnetic signature of the quasi-perpendicular crossing has a relatively sharp upstream–downstream transition, and energetic electrons were detected close to the transition and immediately downstream. The magnetic transition at the quasi-parallel crossing is less clear, energetic electrons were encountered upstream and downstream, and the electron energy spectrum is harder above ∼100 keV. We discuss whether the acceleration is consistent with diffusive shock acceleration theory in each case, and suggest that the quasi-parallel spectral break is due to an energy-dependent interaction between the electrons and short, large-amplitude magnetic structures.

  20. Electron accelerators for environmental protection

    International Nuclear Information System (INIS)

    Zimek, Z.

    1998-01-01

    The primary objective of this publication is to provide information suitable for electron accelerators implementation in facilities applying radiation technology for environmental protection. It should be noticed that radiation processing has been successfully used in the fields of crosslinking polymer curing and medical products sterilization for more than 40 years. Practical application of radiation technology today extends on SO 2 and NO x removal from the flue gas (one of major power intensive radiation processing), destruction and removal of organic chemicals from water, decreasing bacteria content in the irradiated sludge and waste water. On the other hand the increased awareness of environmental pollution hazards and more stringent waste regulations in many countries may open stronger support for environmentally oriented technologies. This publication provides an evaluation of electron accelerators capabilities in respect of environmental applications where technological and economical criteria are now well defined. In order to determine the potential of electron accelerators, the literature data were examined as well visits and meetings with various accelerator manufacturers were performed by the author. Experience of the author in accelerator facilities construction and exploitation including those which were used for environmental protection are significant part of this publication. The principle of accelerator action was described in Chapter 1. Early development, accelerator classification and fields of accelerators application were included to this chapter as well. Details of accelerator construction was described in Chapter 2 to illustrate physical capability of accelerators to perform the function of ionizing radiation source. Electron beam extraction devices, under beam equipment, electron beam parameters and measuring methods were characterized in this chapter as well. Present studies of accelerator technology was described in Chapter 3, where

  1. Electron acceleration in laser-plasma interaction: development and characterization of an optical injector

    International Nuclear Information System (INIS)

    Rechatin, C.

    2009-09-01

    In any particle accelerator, the injector plays a crucial role since it determines most of the characteristics of the accelerated beam. This is also true for laser-plasma accelerators, that are based on the interaction of an ultra short, ultra intense laser with an underdense plasma. However, due to the compactness of these accelerators, injection is a real challenge: to obtain a good beam quality, injected electron beams have to be ultra short and precisely synchronized with the laser. In this manuscript, the relevance of an optical injector, that relies on a second laser pulse, is experimentally demonstrated. With this injector, mono energetic electron beams have been produced in a stable manner. Moreover, this injector gives control over the electron beam parameters. Using the parameters of the second laser pulse, it has been proven that the energy, the charge and the energy spread of the accelerated beam can be simply tuned. Those additional controls make it possible to study in great details the physical phenomena at play during the acceleration. Beam loading effects, due to the interaction of the accelerated bunch with the plasma, have been identified and studied. With optimized injector parameters, the narrowest electron beams measured to date in the laser plasma interaction have been obtained, with a relative energy spread of 1%. (author)

  2. Influence of high energy electrons on ECRH in LHD

    Directory of Open Access Journals (Sweden)

    Ogasawara S.

    2012-09-01

    Full Text Available The central bulk electron temperature of more than 20 keV is achieved in LHD as a result of increasing the injection power and the lowering the electron density near 2 × 1018 m−3. Such collision-less regime is important from the aspect of the neoclassical transport and also the potential structure formation. The presences of appreciable amount of high energy electrons are indicated from hard X-ray PHA, and the discrepancy between the stored energy and kinetic energy estimated from Thomson scattering. ECE spectrum are also sensitive to the presence of high energy electrons and discussed by solving the radiation transfer equation. The ECRH power absorption to the bulk and the high energy electrons are dramatically affected by the acceleration and the confinement of high energy electrons. The heating mechanisms and the acceleration process of high energy electrons are discussed by comparing the experimental results and the ray tracing calculation under assumed various density and mean energy of high energy electrons.

  3. The use and potential application of electron accelerator in Indonesia

    International Nuclear Information System (INIS)

    Danu, Sugiarto

    2003-01-01

    The use of electron accelerator in Indonesia for research and development, radiation services, commercial purposes and potential application in the future is described. A pilot plant for radiation curing technology particularly for wood surface coating using low energy electron accelerator (300 keV, 50 mA; installed in 1984) and a EBM GJ 2 (2 MeV, 10 mA, installed in 1994) for R and D of crosslinking process such as wire and cable and heat shrinkable tube and sheets in Center for Research and Development of Isotopes and Radiation Technology, Jakarta, and also a low energy electron accelerator (installed in 1998) in a private company, PT Gajah Tunggai, are being mainly used. Their performances are presented with activities achieved in the fields of wood surface coating, vulcanization of natural rubber latex, grafting of polyethylene terephthalate (PET), radiation sterilization, degradation of cellulose and, as promising applications, radiation curing for composite production and uses for environmental preservation are introduced. (S. Ohno)

  4. The use and potential application of electron accelerator in Indonesia

    Energy Technology Data Exchange (ETDEWEB)

    Danu, Sugiarto [National Nuclear Energy Agency, Center for Research and Development of Isotopes and Radiation Technology, Jakarta (Indonesia)

    2003-02-01

    The use of electron accelerator in Indonesia for research and development, radiation services, commercial purposes and potential application in the future is described. A pilot plant for radiation curing technology particularly for wood surface coating using low energy electron accelerator (300 keV, 50 mA; installed in 1984) and a EBM GJ 2 (2 MeV, 10 mA, installed in 1994) for R and D of crosslinking process such as wire and cable and heat shrinkable tube and sheets in Center for Research and Development of Isotopes and Radiation Technology, Jakarta, and also a low energy electron accelerator (installed in 1998) in a private company, PT Gajah Tunggai, are being mainly used. Their performances are presented with activities achieved in the fields of wood surface coating, vulcanization of natural rubber latex, grafting of polyethylene terephthalate (PET), radiation sterilization, degradation of cellulose and, as promising applications, radiation curing for composite production and uses for environmental preservation are introduced. (S. Ohno)

  5. Modeling of electron cyclotron resonance acceleration in a stationary inhomogeneous magnetic field

    Directory of Open Access Journals (Sweden)

    Valeri D. Dougar-Jabon

    2008-04-01

    Full Text Available In this paper, the cyclotron autoresonance acceleration of electrons in a stationary inhomogeneous magnetic field is studied. The trajectory and energy of electrons are found through a numerical solution of the relativistic Newton-Lorentz equation by a finite difference method. The electrons move along a TE_{112} cylinder cavity in a steady-state magnetic field whose axis coincides with the cavity axis. The magnetic field profile is such that it keeps the phase difference between the electric microwave field and the electron velocity vector within the acceleration phase band. The microwaves amplitude of 6  kV/cm is used for numerical calculations. It is shown that an electron with an initial longitudinal energy of 8 keV can be accelerated up to 260 keV by 2.45 GHz microwaves at a distance of 17 cm.

  6. Field-reversed bubble in deep plasma channels for high quality electron acceleration

    CERN Document Server

    Pukhov, A; Tueckmantel, T; Thomas, J; Yu, I; Kostyukov, Yu

    2014-01-01

    We study hollow plasma channels with smooth boundaries for laser-driven electron acceleration in the bubble regime. Contrary to the uniform plasma case, the laser forms no optical shock and no etching at the front. This increases the effective bubble phase velocity and energy gain. The longitudinal field has a plateau that allows for mono-energetic acceleration. We observe as low as 10−3 r.m.s. relative witness beam energy uncertainty in each cross-section and 0.3% total energy spread. By varying plasma density profile inside a deep channel, the bubble fields can be adjusted to balance the laser depletion and dephasing lengths. Bubble scaling laws for the deep channel are derived. Ultra-short pancake-like laser pulses lead to the highest energies of accelerated electrons per Joule of laser pulse energy.

  7. Auroral electron acceleration

    International Nuclear Information System (INIS)

    Bryant, D.A.

    1989-10-01

    Two theories of auroral electron acceleration are discussed. Part 1 examines the currently widely held view that the acceleration is an ordered process in a quasi-static electric field. It is suggested that, although there are many factors seeming to support this theory, the major qualifications and uncertainties that have been identified combine to cast serious doubt over its validity. Part 2 is devoted to a relatively new interpretation in terms of stochastic acceleration in turbulent electric fields. This second theory, which appears to account readily for most known features of the electron distribution function, is considered to provide a more promising approach to this central question in magnetospheric plasma physics. (author)

  8. Utilization of 5 MeV electron accelerator center and perspective

    International Nuclear Information System (INIS)

    Tanaka, Hiromi

    1990-01-01

    Electron beam process gives instantaneous effect as compared with heating process, and has such merits that energy consumption is very small, objects can be treated from outside, harmful chemicals are not used and treatment can be done as packed. The spread of electron beam process is largely due to the results of the development of highly reliable accelerators and utilization technologies, but as observed from all industrial fields, it is limited to only a part. In order to contribute to the solution of problems and the spread of electron beam process, Sumitomo Heavy Industries, Ltd. installed a 5 MeV, 200 kW large power accelerator developed by RDI in USA in the Electron Irradiation Application and Development Center opened in Tsukuba City. The Center was completed in June, 1989, and has carried out the activities of the development of irradiation utilization technologies, test irradiation and entrusted irradiation service. The features of electron beam process are high dose rate, the possibility of on and off as occasion demands, the preparation of radiation sources and the disposal of wastes being unnecessary, and no environmental problem. The industrialized processes, the types, energy and use of electron accelerators, the Tsukuba irradiation facilities and others are reported. (K.I.)

  9. The use of electron accelerators for fresh fruit irradiation

    International Nuclear Information System (INIS)

    Ferdes, O.; Minea, R.

    2000-01-01

    There are presented the results of tests concerning the effects of accelerated electron-beam to some early fresh fruits like strawberries, cherries, sour-cherries and apples. The irradiation were performed on common varieties, in normal conditions, to the NILPRP-Electron Accelerator Laboratory facility consisting in electron-beam accelerators which have the following parameters: - mean beam current, 5 μA; - electron mean energy approximately, 7 MeV; - pulse period, 3.5 μs. The doses varied between 0.5-3.0 kGy and the dose rate was about 1500 Gy/min. It was determined the fruit shelf life and there were analysed the main organoleptic and nutritional properties, as: size, shape, colour, dry weight, acidity, total and reducing sugars, ascorbic acid content and other. For the electron-beam treated fruits it was pointed out an increase in freshness and shelf life extension by 5-7 days for strawberries and more than two weeks for cherries. Otherwise, for the applied doses, the electron-beam irradiation did not produce any significant changes in the fruit characteristic values. These results lead to the conclusion that the electron accelerators could be successfully used as a technological solution for the fresh fruits processing, in view of shelf life extension. There are presented also some technical and economical considerations on the feasibility of this technology and on the use of electron-beam machines for food irradiation. (authors)

  10. Collective acceleration of protons by the plasma waves in a counterstreaming electron beam

    International Nuclear Information System (INIS)

    Yan, Y.T.

    1987-03-01

    A novel advanced accelerator is proposed. The counterstreaming electron beam accelerator relies on the same physical mechanism as that of the plasma accelerator but replaces the stationary plasma in the plasma accelerator by a magnetized relativistic electron beam, drifting antiparallel to the driving source and the driven particles, as the wave supporting medium. The plasma wave in a counterstreaming electron beam can be excited either by a density-ramped driving electron beam or by properly beating two laser beams. The fundamental advantages of the counterstreaming electron beam accelerator over the plasma accelerator are a longer and tunable plasma wavelength, a longer pump depletion length or a larger transformer ratio, and easier pulse shaping for the driving source and the driven beam. Thus the energy gain of the driven particles can be greatly enhanced whereas the trapping threshold can be dramatically reduced so as to admit the possibility for proton acceleration

  11. Electron accelerators for radiation processing: Criterions of selection and exploitation

    International Nuclear Information System (INIS)

    Zimek, Zbigniew

    2001-01-01

    The progress in accelerator technology is tightly attached to the continuously advanced development in many branches of technical activity. Although the present level of accelerators development can satisfy most of the commercial requirements, this field continues to expand and improve quality by offering efficient, cheap, reliable, high average beam power commercial units. Accelerator construction must be a compromised between size, efficiency and cost with respect to the field of its application. High power accelerators have been developed to meet specific demands of flue gas treatment and other high throughput to increase the capacity of the progress and reduced unit cost of operation. Automatic control, reliability and reduced maintenance, adequate adoption to process conditions, suitable electron energy and beam power are the basic features of modern accelerator construction. Accelerators have the potential to serve as industrial radiation sources and eventually may replace the isotope sources in future. Electron beam plants can transfer much higher amounts of energy into the irradiated objects than other types of facilities including gamma plants. This provides the opportunity to construct technological lines with high capacity that are more technically and economically suitable with high throughputs, short evidence time and grate versatility

  12. Relativistic electron acceleration in focused laser fields after above-threshold ionization

    International Nuclear Information System (INIS)

    Dodin, I.Y.; Fisch, N.J.

    2003-01-01

    Electrons produced as a result of above-threshold ionization of high-Z atoms can be accelerated by currently producible laser pulses up to GeV energies, as shown recently by Hu and Starace [Phys. Rev. Lett. 88, 245003 (2002)]. To describe electron acceleration by general focused laser fields, we employ an analytical model based on a Hamiltonian, fully relativistic, ponderomotive approach. Though the above-threshold ionization represents an abrupt process compared to laser oscillations, the ponderomotive approach can still adequately predict the resulting energy gain if the proper initial conditions are introduced for the particle drift following the ionization event. Analytical expressions for electron energy gain are derived and the applicability conditions of the ponderomotive formulation are studied both analytically and numerically. The theoretical predictions are supported by numerical computations

  13. Acceleration of electrons at wakefield excitation by a sequence of relativistic electron bunches in dielectric resonator

    International Nuclear Information System (INIS)

    Kiselev, V.A.; Linnik, A.F.; Mirnyj, V.I.; Onishchenko, I.N.; Uskov, V.V.

    2009-01-01

    Method is proposed to divide a regular sequence of electron bunches into parts of bunches driving wakefield and witness bunches, which should be accelerated. It allows to avoid the necessity of additional electron accelerator for witness bunches producing and the necessity of precision short time techniques of injection phase adjusting. The idea concludes to the frequency detuning between bunches repetition frequency and the frequency of the fundamental mode of excited wakefield. Experiments were carried out on the linear resonant accelerator 'Almaz-2', which injected in the dielectric resonator a sequence of 6000 short bunches of relativistic electrons with energy 4.5 MeV, charge 0.16 nC and duration 60 psec each, the repetition interval 360 ps. Frequency detuning was entered by change of frequency of the master generator of the klystron within the limits of one percent so that the phase taper on the length of bunches sequence achieved 2π. Energy spectra of electrons of bunches sequence, which have been propagated through the dielectric resonator are measured and analyzed

  14. Local re-acceleration and a modified thick target model of solar flare electrons

    Science.gov (United States)

    Brown, J. C.; Turkmani, R.; Kontar, E. P.; MacKinnon, A. L.; Vlahos, L.

    2009-12-01

    Context: The collisional thick target model (CTTM) of solar hard X-ray (HXR) bursts has become an almost “standard model” of flare impulsive phase energy transport and radiation. However, it faces various problems in the light of recent data, particularly the high electron beam density and anisotropy it involves. Aims: We consider how photon yield per electron can be increased, and hence fast electron beam intensity requirements reduced, by local re-acceleration of fast electrons throughout the HXR source itself, after injection. Methods: We show parametrically that, if net re-acceleration rates due to e.g. waves or local current sheet electric (E) fields are a significant fraction of collisional loss rates, electron lifetimes, and hence the net radiative HXR output per electron can be substantially increased over the CTTM values. In this local re-acceleration thick target model (LRTTM) fast electron number requirements and anisotropy are thus reduced. One specific possible scenario involving such re-acceleration is discussed, viz, a current sheet cascade (CSC) in a randomly stressed magnetic loop. Results: Combined MHD and test particle simulations show that local E fields in CSCs can efficiently accelerate electrons in the corona and and re-accelerate them after injection into the chromosphere. In this HXR source scenario, rapid synchronisation and variability of impulsive footpoint emissions can still occur since primary electron acceleration is in the high Alfvén speed corona with fast re-acceleration in chromospheric CSCs. It is also consistent with the energy-dependent time-of-flight delays in HXR features. Conclusions: Including electron re-acceleration in the HXR source allows an LRTTM modification of the CTTM in which beam density and anisotropy are much reduced, and alleviates theoretical problems with the CTTM, while making it more compatible with radio and interplanetary electron numbers. The LRTTM is, however, different in some respects such as

  15. Energy loss of a high charge bunched electron beam in plasma: Simulations, scaling, and accelerating wakefields

    Directory of Open Access Journals (Sweden)

    J. B. Rosenzweig

    2004-06-01

    Full Text Available The energy loss and gain of a beam in the nonlinear, “blowout” regime of the plasma wakefield accelerator, which features ultrahigh accelerating fields, linear transverse focusing forces, and nonlinear plasma motion, has been asserted, through previous observations in simulations, to scale linearly with beam charge. Additionally, from a recent analysis by Barov et al., it has been concluded that for an infinitesimally short beam, the energy loss is indeed predicted to scale linearly with beam charge for arbitrarily large beam charge. This scaling is predicted to hold despite the onset of a relativistic, nonlinear response by the plasma, when the number of beam particles occupying a cubic plasma skin depth exceeds that of plasma electrons within the same volume. This paper is intended to explore the deviations from linear energy loss using 2D particle-in-cell simulations that arise in the case of experimentally relevant finite length beams. The peak accelerating field in the plasma wave excited behind the finite-length beam is also examined, with the artifact of wave spiking adding to the apparent persistence of linear scaling of the peak field amplitude into the nonlinear regime. At large enough normalized charge, the linear scaling of both decelerating and accelerating fields collapses, with serious consequences for plasma wave excitation efficiency. Using the results of parametric particle-in-cell studies, the implications of these results for observing severe deviations from linear scaling in present and planned experiments are discussed.

  16. Calorimetry for absorbed dose measurement at 1-4 MeV electron accelerators

    International Nuclear Information System (INIS)

    Miller, A.

    2000-01-01

    Calorimeters are used for dose measurement, calibration and intercomparisons at industrial electron accelerators, and their use at 10 MeV electron accelerators is well documented. The work under this research agreement concerns development of calorimeters for use at electron accelerators with energies in the range of 2-4 MeV. The dose range of the calorimeters is 3-40 kGy, and their temperature stability after irradiation was found to be sufficient for practical use in an industrial environment. Measurement uncertainties were determined to be 5% at k = 2. (author)

  17. Summary of the electron accelerators session

    International Nuclear Information System (INIS)

    Prescott, C.Y.

    1988-10-01

    Since the last High Energy Physics Symposium, there has been considerable progress in the field of polarized electron accelerators. Projects well into construction include the SLC, HERA, and LEP. The status of polarized beams for these projects is discussed in this session. Semiclassical and quantum mechanical calculations of polarizing and depolarizing effects are discussed, for both linear colliders and for storage rings. Substantial progress is continuing in the understanding of depolarizing mechanisms for circular machines. Modelling of these machines is underway. Activities with polarized electron beams at Novosibirsk are described. 8 refs

  18. A novel approach to electron data background treatment in an online wide-angle spectrometer for laser-accelerated ion and electron bunches

    Science.gov (United States)

    Lindner, F. H.; Bin, J. H.; Englbrecht, F.; Haffa, D.; Bolton, P. R.; Gao, Y.; Hartmann, J.; Hilz, P.; Kreuzer, C.; Ostermayr, T. M.; Rösch, T. F.; Speicher, M.; Parodi, K.; Thirolf, P. G.; Schreiber, J.

    2018-01-01

    Laser-based ion acceleration is driven by electrical fields emerging when target electrons absorb laser energy and consecutively leave the target material. A direct correlation between these electrons and the accelerated ions is thus to be expected and predicted by theoretical models. We report on a modified wide-angle spectrometer, allowing the simultaneous characterization of angularly resolved energy distributions of both ions and electrons. Equipped with online pixel detectors, the RadEye1 detectors, the investigation of this correlation gets attainable on a single shot basis. In addition to first insights, we present a novel approach for reliably extracting the primary electron energy distribution from the interfering secondary radiation background. This proves vitally important for quantitative extraction of average electron energies (temperatures) and emitted total charge.

  19. CEBAF [Continuous Electron Beam Accelerator Facility] design report

    International Nuclear Information System (INIS)

    1986-05-01

    This book describes the conceptual design of, and the planning for, the Continuous Electron Beam Accelerator Facility (CEBAF), which will be a high-intensity, continuous-wave electron linear accelerator (linac) for nuclear physics. Its principal scientific goal is to understand the quark structure, behavior, and clustering of individual nucleons in the nuclear medium, and simultaneously to understand the forces governing this behavior. The linac will consist of 1 GeV of accelerating structure, split into two antiparallel 0.5-GeV segments. The segments will be connected by a beam transport system to circulate the electron beams from one segment to the other for up to four complete passes of acceleration. The maximum beam energy will be 4 GeV at a design current of 200 microamperes. The accelerator complex will also include systems to extract three continuous beams from the linac and to deliver them to three experimental halls equipped with detectors and instrumentation for nuclear physics research. The accelerating structure will be kept superconducting within insulated cryostats filled with liquid helium produced at a central helium refrigerator and distributed to the cryostats via insulated transfer lines. An injector, instrumentation and controls for the accelerator, radio-frequency power systems, and several support facilities will also be provided. A cost estimate based on the Work Breakdown Structure has been completed. Assuming a five-year construction schedule starting early in FY 1987, the total estimated cost is $236 million (actual year dollars), including contingency

  20. Electron accelerators for waste processing

    International Nuclear Information System (INIS)

    Kon'kov, N.G.

    1976-01-01

    The documents of the International symposium on radiation vaste processing are presented. Questions on waste utilization with the help of electron accelerators are considered. The electron accelerators are shown to have an advantage over some other ionizing radiation sources. A conclusion is made that radiation methods of waste processing are extensively elaborated in many developed countries. It has been pointed out that an electron accelerator is a most cheap and safe ionizing radiation source primarily for processing of gaseous and liquid wastes

  1. Electron Fermi acceleration in collapsing magnetic traps: Computational and analytical models

    International Nuclear Information System (INIS)

    Gisler, G.; Lemons, D.

    1990-01-01

    The authors consider the heating and acceleration of electrons trapped on magnetic field lines between approaching magnetic mirrors. Such a collapsing magnetic trap and consequent electron energization can occur whenever a curved (or straight) flux tube drifts into a relatively straight (or curved) perpendicular shock. The relativistic, three-dimensional, collisionless test particle simulations show that an initial thermal electron distribution is bulk heated while a few individual electrons are accelerated to many times their original energy before they escape the trap. Upstream field-aligned beams and downstream pancake distributions perpendicular to the field are predicted. In the appropriate limit the simulation results agree well with a nonrelativistic analytic model of the distribution of escaping electrons which is based on the first adiabatic invariant and energy conservation between collisions with the mirrors. Space science and astrophysical applications are discussed

  2. Non-thermal electron acceleration in low Mach number collisionless shocks. II. Firehose-mediated Fermi acceleration and its dependence on pre-shock conditions

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Xinyi; Narayan, Ramesh [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Sironi, Lorenzo [NASA Einstein Postdoctoral Fellow. (United States)

    2014-12-10

    Electron acceleration to non-thermal energies is known to occur in low Mach number (M{sub s} ≲ 5) shocks in galaxy clusters and solar flares, but the electron acceleration mechanism remains poorly understood. Using two-dimensional (2D) particle-in-cell (PIC) plasma simulations, we showed in Paper I that electrons are efficiently accelerated in low Mach number (M{sub s} = 3) quasi-perpendicular shocks via a Fermi-like process. The electrons bounce between the upstream region and the shock front, with each reflection at the shock resulting in energy gain via shock drift acceleration. The upstream scattering is provided by oblique magnetic waves that are self-generated by the electrons escaping ahead of the shock. In the present work, we employ additional 2D PIC simulations to address the nature of the upstream oblique waves. We find that the waves are generated by the shock-reflected electrons via the firehose instability, which is driven by an anisotropy in the electron velocity distribution. We systematically explore how the efficiency of wave generation and of electron acceleration depend on the magnetic field obliquity, the flow magnetization (or equivalently, the plasma beta), and the upstream electron temperature. We find that the mechanism works for shocks with high plasma beta (≳ 20) at nearly all magnetic field obliquities, and for electron temperatures in the range relevant for galaxy clusters. Our findings offer a natural solution to the conflict between the bright radio synchrotron emission observed from the outskirts of galaxy clusters and the low electron acceleration efficiency usually expected in low Mach number shocks.

  3. Femtosecond pulse radiolysis based on photocathode electron accelerator

    International Nuclear Information System (INIS)

    Yoshida, Y.; Yang, Jinfeng; Kondoh, T.; Kozawa, T.; Tagawa, S.

    2006-01-01

    Pulse radiolysis is a powerful tool for studying chemical kinetics and primary processes or reactions of radiation chemistry. In the pulse radiolysis, a short electron beam, which is almost produced by radio-frequency (RF) electron linear accelerator with energy from a few MeV to a few tens MeV, is used as an irradiative source. The electron-induced reactions or phenomena in matter are analyzed by a short-pulse analyzing light (e.g. synchronized lasers) with the time-resolved stroboscopic technique. The time resolution of pulse radiolysis is not only dependent on the electron bunch length, the analyzing light pulse width, the time jitter between the electron bunch and the analyzing light, but also determined by degradation due to the velocity difference between light and the electron in the sample because of the refractive index. In order to improve the time resolution into femtosecond time region, we have develop a new pulse radiolysis based on a concept of 'Equivalent Velocity Spectroscopy (EVS)' to avoid the degradation of the time resolution caused by the velocity difference between the light and the electron beam in sample. In EVS as shown in Fig.1, a femtosecond electron beam produced by a photocathode electron linear accelerator was used, and a synchronized femtosecond laser was used as the analyzing light source. The electron beam and the laser light were injected into sample with an angle (θ), which is determined by the refractive index (n) of the sample. The electron bunch was also rotated with a same angle to make an overlap of the electron bunch with the laser pulse. The degradation of the time resolution caused by the velocity difference between the light and the electron beam can be calculated as g(L)=L[n/c-1/(vcos θ)], where L is the optical path length and v is the velocity of the electron in sample (we can assume v=c for a few tens MeV electron beam).We can thus obtained g(L)=0 by adjusting the incident angle to cos θ=1/n. However, the rotation

  4. Temporary acceleration of electrons while inside an intense electromagnetic pulse

    Directory of Open Access Journals (Sweden)

    Kirk T. McDonald

    1999-12-01

    Full Text Available A free electron can temporarily gain a very significant amount of energy if it is overrun by an intense electromagnetic wave. In principle, this process would permit large enhancements in the center-of-mass energy of electron-electron, electron-positron, and electron-photon interactions if these take place in the presence of an intense laser beam. Practical considerations severely limit the utility of this concept for contemporary lasers incident on relativistic electrons. A more accessible laboratory phenomenon is electron-positron production via an intense laser beam incident on a gas. Intense electromagnetic pulses of astrophysical origin can lead to very energetic photons via bremsstrahlung of temporarily accelerated electrons.

  5. High energy plasma accelerators

    International Nuclear Information System (INIS)

    Tajima, T.

    1985-05-01

    Colinear intense laser beams ω 0 , kappa 0 and ω 1 , kappa 1 shone on a plasma with frequency separation equal to the electron plasma frequency ω/sub pe/ are capable of creating a coherent large longitudinal electric field E/sub L/ = mc ω/sub pe//e of the order of 1GeV/cm for a plasma density of 10 18 cm -3 through the laser beat excitation of plasma oscillations. Accompanying favorable and deleterious physical effects using this process for a high energy beat-wave accelerator are discussed: the longitudinal dephasing, pump depletion, the transverse laser diffraction, plasma turbulence effects, self-steepening, self-focusing, etc. The basic equation, the driven nonlinear Schroedinger equation, is derived to describe this system. Advanced accelerator concepts to overcome some of these problems are proposed, including the plasma fiber accelerator of various variations. An advanced laser architecture suitable for the beat-wave accelerator is suggested. Accelerator physics issues such as the luminosity are discussed. Applications of the present process to the current drive in a plasma and to the excitation of collective oscillations within nuclei are also discussed

  6. Dosimetry for electron beam from Microtron accelerator using chemical dosimeters

    International Nuclear Information System (INIS)

    Joseph, Praveen; Nairy, Rajesha; Sanjeev, Ganesh; Narayana, Y.

    2014-01-01

    The Microtron is a simple, compact, low cost electron accelerator with excellent beam quality and it can accelerate electrons to relativistic energies. The variable energy Microtron at Mangalore University is used for R and D programmes in basic and applied areas of physics, chemistry, materials science, biological sciences, medical science and industry. While studying the effects of radiation, it is essential to have complete knowledge of absorbed dose. In the present study the absorbed dose and the uniformity of dose distribution at various points due to 8 MeV electron beam from Microtron accelerator has been calculated using different chemical dosimeters. From the dosimetry studies for Microtron accelerator, it is observed that the absorbed doses measured at various dose ranges from 2 Gy to 25 kGy using FBX dosimeters at very low doses, Fricke at intermediate doses and alanine and glutamine at higher doses, varied linearly with increasing electron counts. From the dosimetry studies it is observed that there is a linear relation between dose and electron numbers over a wide range of absorbed doses. It is evaluated that the electron counts of about 1.15 x 10 14 corresponds to an absorbed dose of 100 Gy. Fricke dosimetry was carried out to measure the uniformity in dose distribution at a distance of 30 cm from the beam exit window of the accelerator to ensure the availability of uniform irradiation field size. It is observed that a field size of about 4 x 4 cm is available at 30 cm distance from the beam exit window over which the dose distribution is uniform. The sample size during radiological studies using Microtron was restricted to less than 4 x 4 cm dimension at 30 cm distance from the beam exit window to ensure uniform dose distribution to the sample

  7. Radioisotope production with electron accelerators

    International Nuclear Information System (INIS)

    Brinkman, G.A.

    1978-01-01

    The production of radio isotopes with electron accelerators proceeds mainly by secondary photons (bremsstrahlung), produced in an interaction between the electrons and the Coulomb field of the nuclei of a converter. The production yields depend on: the initial electron energy, the Z and thickness of the bremsstrahlung-converter, the Z, A and the thickness of the target, the geometric set up and the cross section for a particular reaction. In this article the production is only considered for thin bremsstrahlung converters in combination with an electron 'sweep' magnet. Simple formulae are given for the calculations of production yields under standard conditions with only sigmasub(q) (the cross section per equivalent quantum) and f (the fraction of the photons that hit the target) as variables and for the calculations of the dose rate at the production point. The units in which the yields are expressed in the literature (units of sigmasub(q) dose, electron beam intensity, monitor response) are discussed. (Auth.)

  8. Observation of laser multiple filamentation process and multiple electron beams acceleration in a laser wakefield accelerator

    International Nuclear Information System (INIS)

    Li, Wentao; Liu, Jiansheng; Wang, Wentao; Chen, Qiang; Zhang, Hui; Tian, Ye; Zhang, Zhijun; Qi, Rong; Wang, Cheng; Leng, Yuxin; Li, Ruxin; Xu, Zhizhan

    2013-01-01

    The multiple filaments formation process in the laser wakefield accelerator (LWFA) was observed by imaging the transmitted laser beam after propagating in the plasma of different density. During propagation, the laser first self-focused into a single filament. After that, it began to defocus with energy spreading in the transverse direction. Two filaments then formed from it and began to propagate independently, moving away from each other. We have also demonstrated that the laser multiple filamentation would lead to the multiple electron beams acceleration in the LWFA via ionization-induced injection scheme. Besides, its influences on the accelerated electron beams were also analyzed both in the single-stage LWFA and cascaded LWFA

  9. High Energy Density Physics and Exotic Acceleration Schemes

    International Nuclear Information System (INIS)

    Cowan, T.; Colby, E.

    2005-01-01

    The High Energy Density and Exotic Acceleration working group took as our goal to reach beyond the community of plasma accelerator research with its applications to high energy physics, to promote exchange with other disciplines which are challenged by related and demanding beam physics issues. The scope of the group was to cover particle acceleration and beam transport that, unlike other groups at AAC, are not mediated by plasmas or by electromagnetic structures. At this Workshop, we saw an impressive advancement from years past in the area of Vacuum Acceleration, for example with the LEAP experiment at Stanford. And we saw an influx of exciting new beam physics topics involving particle propagation inside of solid-density plasmas or at extremely high charge density, particularly in the areas of laser acceleration of ions, and extreme beams for fusion energy research, including Heavy-ion Inertial Fusion beam physics. One example of the importance and extreme nature of beam physics in HED research is the requirement in the Fast Ignitor scheme of inertial fusion to heat a compressed DT fusion pellet to keV temperatures by injection of laser-driven electron or ion beams of giga-Amp current. Even in modest experiments presently being performed on the laser-acceleration of ions from solids, mega-amp currents of MeV electrons must be transported through solid foils, requiring almost complete return current neutralization, and giving rise to a wide variety of beam-plasma instabilities. As keynote talks our group promoted Ion Acceleration (plenary talk by A. MacKinnon), which historically has grown out of inertial fusion research, and HIF Accelerator Research (invited talk by A. Friedman), which will require impressive advancements in space-charge-limited ion beam physics and in understanding the generation and transport of neutralized ion beams. A unifying aspect of High Energy Density applications was the physics of particle beams inside of solids, which is proving to

  10. Electron source with a carbon-fibrous cathode for radiation-technology accelerator

    International Nuclear Information System (INIS)

    Korenev, S.A.

    1994-01-01

    The paper analyses the circuit of a full operating voltage electron source which is a direct-action electron accelerator. The electron source consists of a power supply, high-voltage multiplier-rectifier, vacuum planar diode, vacuum system and control system. The vacuum electron diode contains an autoemission carbon-fibrous cathode and beryllium foil strip anode. The results of measurements of emission characteristics of alumosilicate and carbon-fibrous cathodes are presented. The investigations into test electron source show that it can be used as a basis for creating an electron accelerator which will be capable of generating 1 MW electron beams of 1-2 MeV energy and 1 A current. 3 refs., 1 fig., 1 tab

  11. The neutron dose equivalent around high energy medical electron linear accelerators

    Directory of Open Access Journals (Sweden)

    Poje Marina

    2014-01-01

    Full Text Available The measurement of neutron dose equivalent was made in four dual energy linear accelerator rooms. Two of the rooms were reconstructed after decommissioning of 60Co units, so the main limitation was the space. The measurements were performed by a nuclear track etched detectors LR-115 associated with the converter (radiator that consist of 10B and with the active neutron detector Thermo BIOREM FHT 742. The detectors were set at several locations to evaluate the neutron ambient dose equivalent and/or neutron dose rate to which medical personnel could be exposed. Also, the neutron dose dependence on collimator aperture was analyzed. The obtained neutron dose rates outside the accelerator rooms were several times smaller than the neutron dose rates inside the accelerator rooms. Nevertheless, the measured neutron dose equivalent was not negligible from the aspect of the personal dosimetry with almost 2 mSv a year per person in the areas occupied by staff (conservative estimation. In rooms with 15 MV accelerators, the neutron exposure to the personnel was significantly lower than in the rooms having 18 MV accelerators installed. It was even more pronounced in the room reconstructed after the 60Co decommissioning. This study confirms that shielding from the neutron radiation should be considered when building vaults for high energy linear accelerators, especially when the space constraints exist.

  12. An Inverse Free-Electron-Laser accelerator

    International Nuclear Information System (INIS)

    Fisher, A.S.; Gallardo, J.C.; van Steenbergen, A.; Ulc, S.; Woodle, M.; Sandweiss, J.; Fang, Jyan-Min

    1993-01-01

    Recent work at BNL on electron acceleration using the Inverse Free-Electron Laser (IFEL) has considered a low-energy, high-gradient, multi-stage linear accelerator. Experiments are planned at BNL's Accelerator Test Facility using its 50-MeV linac and 100-GW CO 2 laser. We have built and tested a fast-excitation wiggler magnet with constant field, tapered period, and overall length of 47 cm. Vanadium-Permendur ferromagnetic laminations are stacked in alternation with copper, eddy-current-induced, field reflectors to achieve a 1.4-T peak field with a 4-mm gap and a typical period of 3 cm. The laser beam will pass through the wiggler in a low-loss, dielectric-coated stainless-steel, rectangular waveguide. The attenuation and transverse mode has been measured in waveguide sections of various lengths, with and without the dielectric. Results of 1-D and 3-D IFEL simulations, including wiggler errors, will be presented for several cases: the initial, single-module experiment with ΔE = 39 MeV, a four-module design giving ΔE = 100 MeV in a total length of 2 m, and an eight-module IFEL with ΔE = 210 MeV

  13. Predicting Induced Radioactivity at High Energy Accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Fasso, Alberto

    1999-08-27

    Radioactive nuclides are produced at high-energy electron accelerators by different kinds of particle interactions with accelerator components and shielding structures. Radioactivity can also be induced in air, cooling fluids, soil and groundwater. The physical reactions involved include spallations due to the hadronic component of electromagnetic showers, photonuclear reactions by intermediate energy photons and low-energy neutron capture. Although the amount of induced radioactivity is less important than that of proton accelerators by about two orders of magnitude, reliable methods to predict induced radioactivity distributions are essential in order to assess the environmental impact of a facility and to plan its decommissioning. Conventional techniques used so far are reviewed, and a new integrated approach is presented, based on an extension of methods used at proton accelerators and on the unique capability of the FLUKA Monte Carlo code to handle the whole joint electromagnetic and hadronic cascade, scoring residual nuclei produced by all relevant particles. The radiation aspects related to the operation of superconducting RF cavities are also addressed.

  14. Electron acceleration by surface plasma waves in double metal surface structure

    Science.gov (United States)

    Liu, C. S.; Kumar, Gagan; Singh, D. B.; Tripathi, V. K.

    2007-12-01

    Two parallel metal sheets, separated by a vacuum region, support a surface plasma wave whose amplitude is maximum on the two parallel interfaces and minimum in the middle. This mode can be excited by a laser using a glass prism. An electron beam launched into the middle region experiences a longitudinal ponderomotive force due to the surface plasma wave and gets accelerated to velocities of the order of phase velocity of the surface wave. The scheme is viable to achieve beams of tens of keV energy. In the case of a surface plasma wave excited on a single metal-vacuum interface, the field gradient normal to the interface pushes the electrons away from the high field region, limiting the acceleration process. The acceleration energy thus achieved is in agreement with the experimental observations.

  15. Parallel electric fields accelerating ions and electrons in the same direction

    International Nuclear Information System (INIS)

    Hultqvist, B; Lundin, R.

    1988-01-01

    In this contribution the authors present Viking observations of electrons and positive ions which move upward along the magnetic field lines with energies of the same order of magnitude. The authors propose that both ions and electrons are accelerated by an electric field which has low-frequency temporal variations such that the ions experience and average electrostatic potential drop along the magnetic field lines whereas the upward streaming electrons are accelerated in periods of downward pointing electric field which is quasi-static for the electrons and forces them to beam out of the field region before the field changes direction

  16. Dealing with post-accelerated electrons in the ITER SINGAP accelerator

    International Nuclear Information System (INIS)

    Esch, H. de; Hemsworth, R.S.

    2006-01-01

    Electrons formed by stripping of the negative deuterium beam can be accelerated up to 960 keV in the 1 MeV SINGAP 40 A negative ion accelerator proposed by Europe for the ITER neutral beam injectors. SINGAP accelerates 1280 pre-accelerated 40 keV deuterium beamlets to 1 MeV in a single 350 mm wide gap. At the expected gas pressure of 0.03 Pa inside the accelerator, 2.7 MW of electrons are calculated to leave the accelerator and strike various beamline components, especially the neutraliser. The accelerators of the ITER injectors are designed to produce 4 '' column '' beams which pass through the 4 vertical channels of the neutraliser. Unperturbed the accelerated electrons create small, high power density, 3.3 kW/cm 2 , spots on the leading edges of the neutraliser channels, which is far in excess of their power handling capability. The hot spots arise from the overlapping of beamlets due to the bending induced by the far field of the magnetic filter in the ion source. The proposed solution bends the electrons further downwards, redistributing the power over the neutraliser floor, a vertical electron dump perpendicular to the beam axis located below the neutraliser entrance, and the neutraliser entrance. The bending is to be effected by a magnetic field transverse to the beam direction at the exit of the post-acceleration grid. This field is created by vertical columns of permanent magnets either side of each column beam. After passing between the magnet columns, the electron beams reach the electron dump with a maximum power density of 2.1 kW/cm 2 . The peak power density on the neutraliser entrance is 1.35 kW/cm 2 and on the neutraliser floor 0.82 kW/cm 2 . Electron backscattering would reduce all the numbers by 20%. To further reduce the average power density seen by the beamline components it is proposed to sweep the electron beam in an oscillatory fashion. It is suggested that a failsafe, inexpensive, way is to use a power supply with a ripple of ± 10% to

  17. Relativistic electron acceleration by net inverse bremsstrahlung in a laser-irradiated plasma

    International Nuclear Information System (INIS)

    Kim, S.H.; Chen, K.W.

    1985-01-01

    Using the quantum-kinetic method, the net acceleration of relativistic electrons in a laser-irradiated plasma is studied as a function of the relevant parameters of the incident laser wave and the plasma wave. It is suggested that, in general, the net acceleration in laser-produced turbulent plasmas is primarily due to inverse bremsstrahlung proceses, and the acceleration gradient exceeds several hundreds gigavolt per meter when the electron energy is large (TeV) and the momentum spread of the beam is properly controlled

  18. Therapeutic dose from a pyroelectric electron accelerator.

    Science.gov (United States)

    Fullem, T Z; Fazel, K C; Geuther, J A; Danon, Y

    2009-11-01

    Simple heating of pyroelectric crystals has been used as the basis for compact sources of X rays, electrons, ions and neutrons. We report on the evaluation of the feasibility of using a portable pyroelectric electron accelerator to deliver a therapeutic dose to tissue. Such a device could be mass produced as a handheld, battery-powered instrument. Experiments were conducted with several crystal sizes in which the crystal was heated inside a vacuum chamber and the emitted electrons were allowed to penetrate a thin beryllium window into the surrounding air. A Faraday cup was used to count the number of electrons that exited the window. The energy of these electrons was determined by measuring the energy spectrum of the X rays that resulted from the electron interactions with the Faraday cup. Based on these measurements, the dose that this source could deliver to tissue was calculated using Monte Carlo calculations. It was found that 10(13) electrons with a peak energy of the order of 100 keV were emitted from the beryllium window and could deliver a dose of 1664 Gy to a 2-cm-diameter, 110-microm-deep region of tissue located 1.5 cm from the window with air between the window and the tissue. This dose level is high enough to consider this technology for medical applications in which shallow energy deposition is beneficial.

  19. Simulating electron clouds in heavy-ion accelerators

    International Nuclear Information System (INIS)

    Cohen, R.H.; Friedman, A.; Covo, M. Kireeff; Lund, S.M.; Molvik, A.W.; Bieniosek, F.M.; Seidl, P.A.; Vay, J.-L.; Stoltz, P.; Veitzer, S.

    2005-01-01

    Contaminating clouds of electrons are a concern for most accelerators of positively charged particles, but there are some unique aspects of heavy-ion accelerators for fusion and high-energy density physics which make modeling such clouds especially challenging. In particular, self-consistent electron and ion simulation is required, including a particle advance scheme which can follow electrons in regions where electrons are strongly magnetized, weakly magnetized, and unmagnetized. The approach to such self-consistency is described, and in particular a scheme for interpolating between full-orbit (Boris) and drift-kinetic particle pushes that enables electron time steps long compared to the typical gyroperiod in the magnets. Tests and applications are presented: simulation of electron clouds produced by three different kinds of sources indicates the sensitivity of the cloud shape to the nature of the source; first-of-a-kind self-consistent simulation of electron-cloud experiments on the high-current experiment [L. R. Prost, P. A. Seidl, F. M. Bieniosek, C. M. Celata, A. Faltens, D. Baca, E. Henestroza, J. W. Kwan, M. Leitner, W. L. Waldron, R. Cohen, A. Friedman, D. Grote, S. M. Lund, A. W. Molvik, and E. Morse, 'High current transport experiment for heavy ion inertial fusion', Physical Review Special Topics, Accelerators and Beams 8, 020101 (2005)], at Lawrence Berkeley National Laboratory, in which the machine can be flooded with electrons released by impact of the ion beam on an end plate, demonstrate the ability to reproduce key features of the ion-beam phase space; and simulation of a two-stream instability of thin beams in a magnetic field demonstrates the ability of the large-time-step mover to accurately calculate the instability

  20. Laser-driven electron accelerators

    International Nuclear Information System (INIS)

    Palmer, R.B.

    1981-01-01

    The following possibilities are discussed: inverse free electron laser (wiggler accelerator); inverse Cerenkov effect; plasma accelerator; dielectric tube; and grating linac. Of these, the grating acceleraton is considered the most attractive alternative

  1. A quality control method for detecting energy changes of medical accelerators

    International Nuclear Information System (INIS)

    McGinley, P.H.

    2000-01-01

    A description is presented of a simple and sensitive method for detecting a change in the energy of the electrons bombarding the target of medical accelerators. This technique is useful for x-ray beams with end point energy in the range of 15.7 to 25 MeV. The method is based on the photoactivation of 16 O and 14 N in a small sample of ammonium nitrate. It was found that the ratio of the activity induced in the oxygen divided by that produced in the nitrogen can be used as a quality control technique to detect a change in the energy of the electrons that bombard the target of the accelerator. An electron energy change of the order of 0.2 MeV can be determined using this method. (author)

  2. Cost evaluation of irradiation system with electron accelerator

    International Nuclear Information System (INIS)

    Kashiwagi, M.

    2003-01-01

    The features of electron beam irradiation system using electron accelerator are direct energy pour into the irradiated material, no third material mixture such as catalyst, suitable for mass production and easy operation and maintenance work available. These features can bring the various applications such as cross-linking action, graft polymerization, radical polymerization and others. The selection of electron accelerator ratings is made under consideration of quality, width and thickness of irradiated material, production amount, dose required for reaction and irradiation atmosphere. Especially in a case of irradiation of wire with high insulation material such as polyethylene, the consideration of maximum thickness toward irradiation direction is necessary to avoid the discharge (Lichtenberg discharge) by charged-up electrons inside insulation material. Therefore, the acceleration voltage should be selected to make the maximum penetration larger than maximum irradiation thickness. The actual model case of estimate the irradiation cost was selected that the irradiation object was polyethylene insulated wire up to AWG no.14, irradiation amount was 5,000 km/month, necessary dose was 200 kGy, operation time was 22 d/month and 8 h/day and actual operation efficiency was considered loss time such as bobbin changing as 80%. The selected ratings of electron accelerator were acceleration voltage of 800 kV, beam current of 100 mA and irradiation width of 180 cm with irradiation pulleys stand of 60 turns x 3 lanes. The initial total cost was estimated as 3 M$(US) and operation cost was evaluated as 215 k$(US). Therefore, the irradiation cost of wire was evaluated as 0.0036 $/m. (author)

  3. Development of 350 keV electron accelerator

    International Nuclear Information System (INIS)

    Qin Jiuchang; Cui Shan; Zhou Wenzhen; Cui Zhipeng; Shi Zhenghu; Lu Zhongcheng; Chen Shangwen; Zhang Lifeng; Cui Zongwei; Huang Jun; Yin Meng

    2007-01-01

    The 350 keV electron accelerator is used for irradiation and production of plas- tic film of the medical infusion bags. The body structure of Van de Graft accelerator and the high voltage power supply of Cockcrof-Walton accelerator are adopted in the electron accelerator. The 350 keV DC power supply is supplied by the high frequency power supply with 14 kHz and 35 kW. The body and DC power supply of the electron accelerator are installed in the tank filled with 0.3 MPa SF 6 . The electron accelerator is compact, self-shielding and suitable for on-line electron beam processing. The main characteristics of the facility are terminal voltage 370 kV, electron beam power 7 kW (350 keV/20 mA), scaning width 70 cm, irradiation dose inuniformity ≤7%. (authors)

  4. Electron surfing acceleration by the electron two-stream instability in a weak magnetic field

    International Nuclear Information System (INIS)

    Dieckmann, M E; Shukla, P K

    2006-01-01

    The thermalization of relativistically flowing colliding plasmas is not well understood. The transition layer, in which both plasmas interact and thermalize, is wide and highly structured and the instabilities in this layer may yield non-thermal particle distributions and shock-less energy dissipation. The objective in this work is to explore the ability of an electron two-stream instability for thermalizing a plasma beam that moves at the mildly relativistic speed 0.3c through weakly magnetized plasma and to identify the resulting particle distributions. It is demonstrated here with particle-in-cell simulations that the electron two-stream instability leads to waves that propagate within a wide angular range relative to the flow velocity. The waves are thus not planar, as required for efficient electron surfing acceleration (ESA). The short lifetime of the waves implies, however, only weak modifications of the ESA by the oblique modes, since the waves are sufficiently homogeneous. The ion (proton) beams are not modulated, which would be required to extract some of their energy. The instability can thus heat the electrons significantly, but it fails to accelerate them to relativistic energies and it cannot form a shock layer by thermalizing the protons, at least not for the system and the resolved timescales considered here

  5. Electron surfing acceleration by the electron two-stream instability in a weak magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Dieckmann, M E; Shukla, P K [Institut fuer Theoretische Physik IV, Ruhr-Universitaet Bochum, D-44780 Bochum (Germany)

    2006-10-15

    The thermalization of relativistically flowing colliding plasmas is not well understood. The transition layer, in which both plasmas interact and thermalize, is wide and highly structured and the instabilities in this layer may yield non-thermal particle distributions and shock-less energy dissipation. The objective in this work is to explore the ability of an electron two-stream instability for thermalizing a plasma beam that moves at the mildly relativistic speed 0.3c through weakly magnetized plasma and to identify the resulting particle distributions. It is demonstrated here with particle-in-cell simulations that the electron two-stream instability leads to waves that propagate within a wide angular range relative to the flow velocity. The waves are thus not planar, as required for efficient electron surfing acceleration (ESA). The short lifetime of the waves implies, however, only weak modifications of the ESA by the oblique modes, since the waves are sufficiently homogeneous. The ion (proton) beams are not modulated, which would be required to extract some of their energy. The instability can thus heat the electrons significantly, but it fails to accelerate them to relativistic energies and it cannot form a shock layer by thermalizing the protons, at least not for the system and the resolved timescales considered here.

  6. Properties of Trapped Electron Bunches in a Plasma Wakefield Accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Kirby, Neil; /SLAC

    2009-10-30

    Plasma-based accelerators use the propagation of a drive bunch through plasma to create large electric fields. Recent plasma wakefield accelerator (PWFA) experiments, carried out at the Stanford Linear Accelerator Center (SLAC), successfully doubled the energy for some of the 42 GeV drive bunch electrons in less than a meter; this feat would have required 3 km in the SLAC linac. This dissertation covers one phenomenon associated with the PWFA, electron trapping. Recently it was shown that PWFAs, operated in the nonlinear bubble regime, can trap electrons that are released by ionization inside the plasma wake and accelerate them to high energies. These trapped electrons occupy and can degrade the accelerating portion of the plasma wake, so it is important to understand their origins and how to remove them. Here, the onset of electron trapping is connected to the drive bunch properties. Additionally, the trapped electron bunches are observed with normalized transverse emittance divided by peak current, {epsilon}{sub N,x}/I{sub t}, below the level of 0.2 {micro}m/kA. A theoretical model of the trapped electron emittance, developed here, indicates that the emittance scales inversely with the square root of the plasma density in the non-linear 'bubble' regime of the PWFA. This model and simulations indicate that the observed values of {epsilon}{sub N,x}/I{sub t} result from multi-GeV trapped electron bunches with emittances of a few {micro}m and multi-kA peak currents. These properties make the trapped electrons a possible particle source for next generation light sources. This dissertation is organized as follows. The first chapter is an overview of the PWFA, which includes a review of the accelerating and focusing fields and a survey of the remaining issues for a plasma-based particle collider. Then, the second chapter examines the physics of electron trapping in the PWFA. The third chapter uses theory and simulations to analyze the properties of the trapped

  7. Radiation Fields in High Energy Accelerators and their impact on Single Event Effects

    CERN Document Server

    García Alía, Rubén; Wrobel, Frédéric; Brugger, Markus

    Including calculation models and measurements for a variety of electronic components and their concerned radiation environments, this thesis describes the complex radiation field present in the surrounding of a high-energy hadron accelerator and assesses the risks related to it in terms of Single Event Effects (SEE). It is shown that this poses not only a serious threat to the respective operation of modern accelerators but also highlights the impact on other high-energy radiation environments such as those for ground and avionics applications. Different LHC-like radiation environments are described in terms of their hadron composition and energy spectra. They are compared with other environments relevant for electronic component operation such as the ground-level, avionics or proton belt. The main characteristic of the high-energy accelerator radiation field is its mixed nature, both in terms of hadron types and energy interval. The threat to electronics ranges from neutrons of thermal energies to GeV hadron...

  8. Electron energy recovery system for negative ion sources

    International Nuclear Information System (INIS)

    Dagenhart, W.K.; Stirling, W.L.

    1982-01-01

    An electron energy recovery system for negative ion sources is provided. The system, employs crossed electric and magnetic fields to separate the electrons from ions as they are extracted from a negative ion source plasma generator and before the ions are accelerated to their full kinetic energy. With the electric and magnetic fields oriented 90* to each other, the electrons are separated from the plasma and remain at approximately the electrical potential of the generator in which they were generated. The electrons migrate from the ion beam path in a precessing motion out of the ion accelerating field region into an electron recovery region provided by a specially designed electron collector electrode. The electron collector electrode is uniformly spaced from a surface of the ion generator which is transverse to the direction of migration of the electrons and the two surfaces are contoured in a matching relationship which departs from a planar configuration to provide an electric field component in the recovery region which is parallel to the magnetic field thereby forcing the electrons to be directed into and collected by the electron collector electrode. The collector electrode is maintained at a potential slightly positive with respect to the ion generator so that the electrons are collected at a small fraction of the full accelerating supply voltage energy

  9. 0.56 GeV laser electron acceleration in ablative-capillary-discharge plasma channel

    International Nuclear Information System (INIS)

    Kameshima, Takashi; Kurokawa, Shin-ichi; Nakajima, Kazuhisa; Hong Wei; Wen Xianlun; Wu Yuchi; Tang Chuanming; Zhu Qihua; Gu Yuqiu; Zhang Baohan; Peng Hansheng; Sugiyama, Kiyohiro; Chen, Liming; Tajima, Toshiki; Kumita, Tetsuro

    2008-01-01

    A high-quality electron beam with a central energy of 0.56 GeV, an energy spread of 1.2% rms, and a divergence of 0.59 mrad rms was produced by means of a 4 cm ablative-capillary-discharge plasma channel driven by a 3.8 J27 fs laser pulse. This is the first demonstration of electron acceleration with an ablative capillary discharge wherein the capillary is stably operated in vacuum with a simple system triggered by a laser pulse. This result of the generation of a high-quality beam provides the prospects to realize a practical accelerator based on laser-plasma acceleration. (author)

  10. Electron Beam Charge Diagnostics for Laser Plasma Accelerators

    International Nuclear Information System (INIS)

    Nakamura, Kei; Gonsalves, Anthony; Lin, Chen; Smith, Alan; Rodgers, David; Donahue, Rich; Byrne, Warren; Leemans, Wim

    2011-01-01

    A comprehensive study of charge diagnostics is conducted to verify their validity for measuring electron beams produced by laser plasma accelerators (LPAs). First, a scintillating screen (Lanex) was extensively studied using subnanosecond electron beams from the Advanced Light Source booster synchrotron, at the Lawrence Berkeley National Laboratory. The Lanex was cross calibrated with an integrating current transformer (ICT) for up to the electron energy of 1.5 GeV, and the linear response of the screen was confirmed for charge density and intensity up to 160 pC/mm 2 and 0.4 pC/(ps mm 2 ), respectively. After the radio-frequency accelerator based cross calibration, a series of measurements was conducted using electron beams from an LPA. Cross calibrations were carried out using an activation-based measurement that is immune to electromagnetic pulse noise, ICT, and Lanex. The diagnostics agreed within ±8%, showing that they all can provide accurate charge measurements for LPAs.

  11. Electron beam charge diagnostics for laser plasma accelerators

    Directory of Open Access Journals (Sweden)

    K. Nakamura

    2011-06-01

    Full Text Available A comprehensive study of charge diagnostics is conducted to verify their validity for measuring electron beams produced by laser plasma accelerators (LPAs. First, a scintillating screen (Lanex was extensively studied using subnanosecond electron beams from the Advanced Light Source booster synchrotron, at the Lawrence Berkeley National Laboratory. The Lanex was cross calibrated with an integrating current transformer (ICT for up to the electron energy of 1.5 GeV, and the linear response of the screen was confirmed for charge density and intensity up to 160  pC/mm^{2} and 0.4  pC/(ps  mm^{2}, respectively. After the radio-frequency accelerator based cross calibration, a series of measurements was conducted using electron beams from an LPA. Cross calibrations were carried out using an activation-based measurement that is immune to electromagnetic pulse noise, ICT, and Lanex. The diagnostics agreed within ±8%, showing that they all can provide accurate charge measurements for LPAs.

  12. Post acceleration of a pseudospark-produced electron beam by an induction linac

    International Nuclear Information System (INIS)

    Ding, B.N.; Myers, T.J.; Rhee, M.J.

    1992-01-01

    Recently, a high-brightness electron beam produced by a simple pseudospark device has been reported. Typically, the electron beam has a peak current of up to 1 kA, FWHM pulse duration of 30 ns, and an effective emittance of 4[ 2 > r2 > - 2] 1/2 = 100 mm-mrad. The normalized brightness of the beam is estimated to be on the order of 10 11 A/(m 2 -rad 2 ). This high-brightness beam may be immediately useful for high current accelerators and free-electron lasers if the beam energy can be boosted up. In this paper, the authors present preliminary results of the post acceleration of the electron beam by using an induction linac. The pseudospark device is modified by adding a trigger electrode in the hollow cavity of the cathode so that the generation of the electron beam is synchronized with the induction linac. A simple induction linac system of 25 kV, 1 kA, 50 ns pulse is being constructed. The electron beam, which is born in a low pressure gas, will be accelerated in the same background gas. This gas provides a sufficient ion channel for necessary focusing of this high-current density beam. Preliminary results on the beam current, energy spectrum, and emittance measurements of the post-accelerated beam will be presented

  13. RF emittance in a low energy electron linear accelerator

    Science.gov (United States)

    Sanaye Hajari, Sh.; Haghtalab, S.; Shaker, H.; Kelisani, M. Dayyani

    2018-04-01

    Transverse beam dynamics of an 8 MeV low current (10 mA) S-band traveling wave electron linear accelerator has been studied and optimized. The main issue is to limit the beam emittance, mainly induced by the transverse RF forces. The linac is being constructed at Institute for Research in Fundamental Science (IPM), Tehran Iran Labeled as Iran's First Linac, nearly all components of this accelerator are designed and constructed within the country. This paper discusses the RF coupler induced field asymmetry and the corresponding emittance at different focusing levels, introduces a detailed beam dynamics design of a solenoid focusing channel aiming to reduce the emittance growth and studies the solenoid misalignment tolerances. In addition it has been demonstrated that a prebuncher cavity with appropriate parameters can help improving the beam quality in the transverse plane.

  14. Dielectric laser acceleration of non-relativistic electrons at a photonic structure

    Energy Technology Data Exchange (ETDEWEB)

    Breuer, John

    2013-08-29

    This thesis reports on the observation of dielectric laser acceleration of non-relativistic electrons via the inverse Smith-Purcell effect in the optical regime. Evanescent modes in the vicinity of a periodic grating structure can travel at the same velocity as the electrons along the grating surface. A longitudinal electric field component is used to continuously impart momentum onto the electrons. This is only possible in the near-field of a suitable photonic structure, which means that the electron beam has to pass the structure within about one wavelength. In our experiment we exploit the third spatial harmonic of a single fused silica grating excited by laser pulses derived from a Titanium:sapphire oscillator and accelerate non-relativistic 28 keV electrons. We measure a maximum energy gain of 280 eV, corresponding to an acceleration gradient of 25 MeV/m, already comparable with state-of-the-art radio-frequency linear accelerators. To experience this acceleration gradient the electrons approach the grating closer than 100 nm. We present the theory behind grating-based particle acceleration and discuss simulation results of dielectric laser acceleration in the near-field of photonic grating structures, which is excited by near-infrared laser light. Our measurements show excellent agreement with our simulation results and therefore confirm the direct acceleration with the light field. We further discuss the acceleration inside double grating structures, dephasing effects of non-relativistic electrons as well as the space charge effect, which can limit the attainable peak currents of these novel accelerator structures. The photonic structures described in this work can be readily concatenated and therefore represent a scalable realization of dielectric laser acceleration. Furthermore, our structures are directly compatible with the microstructures used for the acceleration of relativistic electrons demonstrated in parallel to this work by our collaborators in

  15. Kinetic Simulation of Fast Electron Transport with Ionization Effects and Ion Acceleration

    International Nuclear Information System (INIS)

    Robinson, A. P. L.; Bell, A. R.; Kingham, R. J.

    2005-01-01

    The generation of relativistic electrons and multi-MeV ions is central to ultra intense (> 1018Wcm-2) laser-solid interactions. The production of energetic particles by lasers has a number of potential applications ranging from Fast Ignition ICF to medicine. In terms of the relativistic (fast) electrons the areas of interest can be divided into three areas. Firstly there is the absorption of laser energy into fast electrons and MeV ions. Secondly there is the transport of fast electrons through the solid target. Finally there is a transduction stage, where the fast electron energy is imparted. This may range from being the electrostatic acceleration of ions at a plasma-vacuum interface, to the heating of a compressed core (as in Fast Ignitor ICF).We have used kinetic simulation codes to study the transport stage and electrostatic ion acceleration. (Author)

  16. Charging and the cross-field discharge during electron accelerator operation on a rocket

    International Nuclear Information System (INIS)

    Kellogg, P.J.; Monson, S.J.

    1988-01-01

    We present some limited results obtained from the flight of SCEX II, from Poker Flat, Alaska, on January 31, 1987. Some of the experiments were aimed at understanding neutralization processes around an electron beam emitting rocket. It was expected that electrons drifting in the strong electric fields around the charged rocket would acquire sufficient energy to ionize neutrals, and that the resulting ions would be hurled outward at energies up to the rocket potential. Three hemispherical retarding potential analyzers were ejected from the main payload to measure these ions. This experiment was successful, in spite of arcs which developed around the batteries for the electron guns, which degraded the emitted electron beam to unusable levels except for about 8 sec of the flight. Ions were observed at energies up to 175 eV, the limit of the analyzers. The main payload carried, in addition to the electron accelerator, two arms with conducting elements to act as Langmuir probes, and to measure floating potentials. These measurements show that fields sufficient to accelerate electrons to ionizing energies were present around the rocket. (author)

  17. Electron acceleration at Jupiter: input from cyclotron-resonant interaction with whistler-mode chorus waves

    Directory of Open Access Journals (Sweden)

    E. E. Woodfield

    2013-10-01

    Full Text Available Jupiter has the most intense radiation belts of all the outer planets. It is not yet known how electrons can be accelerated to energies of 10 MeV or more. It has been suggested that cyclotron-resonant wave-particle interactions by chorus waves could accelerate electrons to a few MeV near the orbit of Io. Here we use the chorus wave intensities observed by the Galileo spacecraft to calculate the changes in electron flux as a result of pitch angle and energy diffusion. We show that, when the bandwidth of the waves and its variation with L are taken into account, pitch angle and energy diffusion due to chorus waves is a factor of 8 larger at L-shells greater than 10 than previously shown. We have used the latitudinal wave intensity profile from Galileo data to model the time evolution of the electron flux using the British Antarctic Survey Radiation Belt (BAS model. This profile confines intense chorus waves near the magnetic equator with a peak intensity at ∼5° latitude. Electron fluxes in the BAS model increase by an order of magnitude for energies around 3 MeV. Extending our results to L = 14 shows that cyclotron-resonant interactions with chorus waves are equally important for electron acceleration beyond L = 10. These results suggest that there is significant electron acceleration by cyclotron-resonant interactions at Jupiter contributing to the creation of Jupiter's radiation belts and also increasing the range of L-shells over which this mechanism should be considered.

  18. Proceedings of the FNCA workshop on application of electron accelerator

    International Nuclear Information System (INIS)

    Yoshii, Fumio; Kume, Tamikazu

    2003-02-01

    'Forum for Nuclear Cooperation in Asia (FNCA) Workshop on Application of Electron Accelerator' was sponsored by the Ministry of Education, Culture, Sports, Science and Technology (MEXT) and hosted by Japan Atomic Energy Research Institute (JAERI) and Japan Atomic Industry Forum (JAIF). It was held at the Takasaki Radiation Chemistry Research Establishment (TRCRE), JAERI, Takasaki, Japan from 28 January to 1 February, 2002. The Workshop was attended by experts on application of electron accelerator from each of the participating countries, i.e. China, Indonesia, Korea, Malaysia, The Philippines, Thailand and Vietnam and 16 participants from Japan. A total of 17 papers including invited papers on the current status of application of electron accelerator in the participating countries were presented. The characteristics of various kinds of electron accelerators were introduced. Current research and development on the utilization radiation processing for natural rubber latex, natural polymer solution, polymer films, sterilization of spices and seeds, radiation treatment of flue gases and dioxin in liquid, solid, and gases were reported. Based on the proposed needs from the participating countries, the work plan was discussed and agreed on application of electron accelerator for liquid and for solid (thin films and granules/powder). All manuscripts submitted by every speaker were included in the proceedings. The 16 of the presented papers are indexed individually. (J.P.N.)

  19. Proceedings of the FNCA workshop on application of electron accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Yoshii, Fumio; Kume, Tamikazu (eds.) [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

    2003-02-01

    'Forum for Nuclear Cooperation in Asia (FNCA) Workshop on Application of Electron Accelerator' was sponsored by the Ministry of Education, Culture, Sports, Science and Technology (MEXT) and hosted by Japan Atomic Energy Research Institute (JAERI) and Japan Atomic Industry Forum (JAIF). It was held at the Takasaki Radiation Chemistry Research Establishment (TRCRE), JAERI, Takasaki, Japan from 28 January to 1 February, 2002. The Workshop was attended by experts on application of electron accelerator from each of the participating countries, i.e. China, Indonesia, Korea, Malaysia, The Philippines, Thailand and Vietnam and 16 participants from Japan. A total of 17 papers including invited papers on the current status of application of electron accelerator in the participating countries were presented. The characteristics of various kinds of electron accelerators were introduced. Current research and development on the utilization radiation processing for natural rubber latex, natural polymer solution, polymer films, sterilization of spices and seeds, radiation treatment of flue gases and dioxin in liquid, solid, and gases were reported. Based on the proposed needs from the participating countries, the work plan was discussed and agreed on application of electron accelerator for liquid and for solid (thin films and granules/powder). All manuscripts submitted by every speaker were included in the proceedings. The 16 of the presented papers are indexed individually. (J.P.N.)

  20. New generation of compact electron accelerators for radiation technologies

    International Nuclear Information System (INIS)

    Auslender, V.L.; Balakin, V.E.; Kraynov, G.S.

    1995-01-01

    Compact electron accelerators with energy range 0.25-1.0 MeV and beam power up to 32 kw are described. The feeding high voltage is formed by converter (working frequency 20 khz), coreless step-up transformer and a set of rectifying sections. The rectifying multiplier circuit used in rectifying sections permits to reach voltage gradient along accelerator's axis up to 14 kV/cm. The accelerators with vertical and horizontal position are described. The accelerators can be produced together with local radiation shielding and various underbeam transportation systems for irradiation of different products. Such version can be installed in any room facing general requirements for electric equipment

  1. submitter Parametric study of transport beam lines for electron beams accelerated by laser-plasma interaction

    CERN Document Server

    Scisciò, M; Migliorati, M; Mostacci, A; Palumbo, L; Papaphilippou, Y; Antici, P

    2016-01-01

    In the last decade, laser-plasma acceleration of high-energy electrons has attracted strong attention in different fields. Electrons with maximum energies in the GeV range can be laser-accelerated within a few cm using multi-hundreds terawatt (TW) lasers, yielding to very high beam currents at the source (electron bunches with up to tens-hundreds of pC in a few fs). While initially the challenge was to increase the maximum achievable electron energy, today strong effort is put in the control and usability of these laser-generated beams that still lack of some features in order to be used for applications where currently conventional, radio-frequency (RF) based, electron beam lines represent the most common and efficient solution. Several improvements have been suggested for this purpose, some of them acting directly on the plasma source, some using beam shaping tools located downstream. Concerning the latter, several studies have suggested the use of conventional accelerator magnetic devices (such as quadrupo...

  2. Construction of a 1 MeV Electron Accelerator for High Precision Beta Decay Studies

    Science.gov (United States)

    Longfellow, Brenden

    2014-09-01

    Beta decay energy calibration for detectors is typically established using conversion sources. However, the calibration points from conversion sources are not evenly distributed over the beta energy spectrum and the foil backing of the conversion sources produces perturbations in the calibration spectrum. To improve this, an external, tunable electron beam coupled by a magnetic field can be used to calibrate the detector. The 1 MeV electron accelerator in development at Triangle Universities Nuclear Laboratory (TUNL) utilizes a pelletron charging system. The electron gun shoots 104 electrons per second with an energy range of 50 keV to 1 MeV and is pulsed at a 10 kHz rate with a few ns width. The magnetic field in the spectrometer is 1 T and guiding fields of 0.01 to 0.05 T for the electron gun are used to produce a range of pitch angles. This accelerator can be used to calibrate detectors evenly over its energy range and determine the detector response over a range of pitch angles. Beta decay energy calibration for detectors is typically established using conversion sources. However, the calibration points from conversion sources are not evenly distributed over the beta energy spectrum and the foil backing of the conversion sources produces perturbations in the calibration spectrum. To improve this, an external, tunable electron beam coupled by a magnetic field can be used to calibrate the detector. The 1 MeV electron accelerator in development at Triangle Universities Nuclear Laboratory (TUNL) utilizes a pelletron charging system. The electron gun shoots 104 electrons per second with an energy range of 50 keV to 1 MeV and is pulsed at a 10 kHz rate with a few ns width. The magnetic field in the spectrometer is 1 T and guiding fields of 0.01 to 0.05 T for the electron gun are used to produce a range of pitch angles. This accelerator can be used to calibrate detectors evenly over its energy range and determine the detector response over a range of pitch angles

  3. Acceleration and Precipitation of Electrons during Substorm Dipolarization Events

    Science.gov (United States)

    Ashour-Abdalla, Maha; Richard, Robert; Donovan, Eric; Zhou, Meng; Goldstein, Mevlyn; El-Alaoui, Mostafa; Schriver, David; Walker, Raymond

    Observations and modeling have established that during geomagnetically disturbed times the Earth’s magnetotail goes through large scale changes that result in enhanced electron precipitation into the ionosphere and earthward propagating dipolarization fronts that contain highly energized plasma. Such events originate near reconnection regions in the magnetotail at about 20-30 R_E down tail. As the dipolarization fronts propagate earthward, strong acceleration of both ions and electrons occurs due to a combination of non-adiabatic and adiabatic (betatron and Fermi) acceleration, with particle energies reaching up to 100 keV within the dipolarization front. One consequence of the plasma transport that occurs during these events is direct electron precipitation into the ionosphere, which form auroral precipitation. Using global kinetic simulations along with spacecraft and ground-based data, causes of electron precipitation are determined during well-documented, disturbed events. It is found that precipitation of keV electrons in the pre-midnight sector at latitudes around 70(°) occur due to two distinct physical processes: (1) higher latitude (≥72(°) ) precipitation due to electrons that undergo relatively rapid non-adiabatic pitch angle scattering into the loss cone just earthward of the reconnection region at around 20 R_E downtail, and (2) lower latitude (≤72(°) ) precipitation due to electrons that are more gradually accelerated primarily parallel to the geomagnetic field during its bounce motion by Fermi acceleration and enter the loss cone much closer to the Earth at 10-15 R_E, somewhat tailward of the dipolarization front. As the dipolarization fronts propagate earthward, the electron precipitation shifts to lower latitudes and occurs over a wider region in the auroral ionosphere. Our results show a direct connection between electron acceleration in the magnetotail and electron precipitation in the ionosphere during disturbed times. The electron

  4. Proton-driven plasma wakefield acceleration: a path to the future of high-energy particle physics

    International Nuclear Information System (INIS)

    Assmann, R; Gross, M; Bingham, R; Holloway, J; Bohl, T; Bracco, C; Butterworth, A; Feldbaumer, E; Goddard, B; Gschwendtner, E; Buttenschön, B; Caldwell, A; Chattopadhyay, S; Cipiccia, S; Jaroszynski, D; Fonseca, R A; Grulke, O; Kempkes, P; Huang, C; Jolly, S

    2014-01-01

    New acceleration technology is mandatory for the future elucidation of fundamental particles and their interactions. A promising approach is to exploit the properties of plasmas. Past research has focused on creating large-amplitude plasma waves by injecting an intense laser pulse or an electron bunch into the plasma. However, the maximum energy gain of electrons accelerated in a single plasma stage is limited by the energy of the driver. Proton bunches are the most promising drivers of wakefields to accelerate electrons to the TeV energy scale in a single stage. An experimental program at CERN—the AWAKE experiment—has been launched to study in detail the important physical processes and to demonstrate the power of proton-driven plasma wakefield acceleration. Here we review the physical principles and some experimental considerations for a future proton-driven plasma wakefield accelerator. (paper)

  5. Proton-driven plasma wakefield acceleration: a path to the future of high-energy particle physics

    CERN Document Server

    Assmann, R.; Bohl, T.; Bracco, C.; Buttenschon, B.; Butterworth, A.; Caldwell, A.; Chattopadhyay, S.; Cipiccia, S.; Feldbaumer, E.; Fonseca, R.A.; Goddard, B.; Gross, M.; Grulke, O.; Gschwendtner, E.; Holloway, J.; Huang, C.; Jaroszynski, D.; Jolly, S.; Kempkes, P.; Lopes, N.; Lotov, K.; Machacek, J.; Mandry, S.R.; McKenzie, J.W.; Meddahi, M.; Militsyn, B.L.; Moschuering, N.; Muggli, P.; Najmudin, Z.; Noakes, T.C.Q.; Norreys, P.A.; Oz, E.; Pardons, A.; Petrenko, A.; Pukhov, A.; Rieger, K.; Reimann, O.; Ruhl, H.; Shaposhnikova, E.; Silva, L.O.; Sosedkin, A.; Tarkeshian, R.; Trines, R.M.G.N.; Tuckmantel, T.; Vieira, J.; Vincke, H.; Wing, M.; Xia, G.

    2014-01-01

    New acceleration technology is mandatory for the future elucidation of fundamental particles and their interactions. A promising approach is to exploit the properties of plasmas. Past research has focused on creating large-amplitude plasma waves by injecting an intense laser pulse or an electron bunch into the plasma. However, the maximum energy gain of electrons accelerated in a single plasma stage is limited by the energy of the driver. Proton bunches are the most promising drivers of wakefields to accelerate electrons to the TeV energy scale in a single stage. An experimental program at CERN -- the AWAKE experiment -- has been launched to study in detail the important physical processes and to demonstrate the power of proton-driven plasma wakefield acceleration. Here we review the physical principles and some experimental considerations for a future proton-driven plasma wakefield accelerator.

  6. 3D electromagnetic simulation of spatial autoresonance acceleration of electron beams

    International Nuclear Information System (INIS)

    Dugar-Zhabon, V D; Orozco, E A; González, J D

    2016-01-01

    The results of full electromagnetic simulations of the electron beam acceleration by a TE 112 linear polarized electromagnetic field through Space Autoresonance Acceleration mechanism are presented. In the simulations, both the self-sustaned electric field and selfsustained magnetic field produced by the beam electrons are included into the elaborated 3D Particle in Cell code. In this system, the space profile of the magnetostatic field maintains the electron beams in the acceleration regime along their trajectories. The beam current density evolution is calculated applying the charge conservation method. The full magnetic field in the superparticle positions is found by employing the trilinear interpolation of the mesh node data. The relativistic Newton-Lorentz equation presented in the centered finite difference form is solved using the Boris algorithm that provides visualization of the beam electrons pathway and energy evolution. A comparison between the data obtained from the full electromagnetic simulations and the results derived from the motion equation depicted in an electrostatic approximation is carried out. It is found that the self-sustained magnetic field is a factor which improves the resonance phase conditions and reduces the beam energy spread. (paper)

  7. Intensive beam dosimetry of accelerated electrons of low energy

    International Nuclear Information System (INIS)

    Oproiu, C.

    1984-01-01

    Dosimetric control of electron beams ranging between 0.3 MeV and 10 MeV is treated using proper dosimetric methods relying on calorimetry, Tricke chemical solution, dosimetric film of cellulose triacetate. Proper methods are pointed out for measurements in inhomogeneous fields, bringing into evidence the results obtained in deep dose distributions and on the surface of irradiated material. A measuring method of dose distribution in depth by means of an assembly with calorimetric elements, as well as a practical method to pointing out dose distribution and equidose curves along the depth of irradiated electric cable depth are presented. In order to find out the main sizes of accelerated electron beam one uses proper devices relying on Faraday cylinder, total absorption calorimeter, ionization chambers. (author)

  8. Free-electron laser as a power source for a high-gradient accelerating structure

    International Nuclear Information System (INIS)

    Sessler, A.M.

    1982-02-01

    A two beam colliding linac accelerator is proposed in which one beam is intense (approx. = 1KA), of low energy (approx. = MeV), and long (approx. = 100 ns) and provides power at 1 cm wavelength through a free-electron-laser-mechanism to the second beam of a few electrons (approx. = 10 11 ), which gain energy at the rate of 250 MeV/m in a high-gradient accelerating structure and hence reach 375 GeV in 1.5 km. The intense beam is given energy by induction units and gains, and losses by radiation, 250 keV/m thus supplying 25 J/m to the accelerating structure. The luminosity, L, of two such linacs would be, at a repetition rate of 1 kHz, L = 4. x 10 32 cm -2 s -1

  9. Laser plasma acceleration of electrons with multi-PW laser beams in the frame of CILEX

    Energy Technology Data Exchange (ETDEWEB)

    Cros, B., E-mail: brigitte.cros@u-psud.fr [LPGP, CNRS and Université Paris Sud, Orsay (France); Paradkar, B.S. [LPGP, CNRS and Université Paris Sud, Orsay (France); Davoine, X. [CEA DAM DIF, Arpajon F-91297 (France); Chancé, A. [CEA IRFU-SACM, Gif-Sur-Yvette (France); Desforges, F.G. [LPGP, CNRS and Université Paris Sud, Orsay (France); Dobosz-Dufrénoy, S. [CEA DSM-IRAMIS-SPAM, Gif-sur-Yvette (France); Delerue, N. [LAL, CNRS and Universit Paris Sud, Orsay (France); Ju, J.; Audet, T.L.; Maynard, G. [LPGP, CNRS and Université Paris Sud, Orsay (France); Lobet, M.; Gremillet, L. [CEA DAM DIF, Arpajon F-91297 (France); Mora, P. [CPhT, CNRS and Ecole Polytechnique, Palaiseau (France); Schwindling, J.; Delferrière, O. [CEA IRFU-SACM, Gif-Sur-Yvette (France); Bruni, C.; Rimbault, C.; Vinatier, T. [LAL, CNRS and Universit Paris Sud, Orsay (France); Di Piazza, A. [Max-Planck-Institut für Kernphysik, Heidelberg (Germany); Grech, M. [LULI, Ecole Polytechnique, CNRS, CEA, UPMC, Palaiseau (France); and others

    2014-03-11

    Laser plasma acceleration of electrons has progressed along with advances in laser technology. It is thus expected that the development in the near-future of multi-PW-class laser and facilities will enable a vast range of scientific opportunities for laser plasma acceleration research. On one hand, high peak powers can be used to explore the extremely high intensity regime of laser wakefield acceleration, producing for example large amounts of electrons in the GeV range or generating high energy photons. On the other hand, the available laser energy can be used in the quasi-linear regime to create accelerating fields in large volumes of plasma and study controlled acceleration in a plasma stage of externally injected relativistic particles, either electrons or positrons. In the frame of the Centre Interdisciplinaire de la Lumière EXtrême (CILEX), the Apollon-10P laser will deliver two beams at the 1 PW and 10 PW levels, in ultra-short (>15fs) pulses, to a target area dedicated to electron acceleration studies, such as the exploration of the non-linear regimes predicted theoretically, or multi-stage laser plasma acceleration.

  10. Ultra-High-Contrast Laser Acceleration of Relativistic Electrons in Solid Targets

    Science.gov (United States)

    Higginson, Drew Pitney

    The cone-guided fast ignition approach to Inertial Confinement Fusion requires laser-accelerated relativistic electrons to deposit kilojoules of energy within an imploded fuel core to initiate fusion burn. One obstacle to coupling electron energy into the core is the ablation of material, known as preplasma, by laser energy proceeding nanoseconds prior to the main pulse. This causes the laser-absorption surface to be pushed back hundreds of microns from the initial target surface; thus increasing the distance that electrons must travel to reach the imploded core. Previous experiments have shown an order of magnitude decrease in coupling into surrogate targets when intentionally increasing the amount of preplasma. Additionally, for electrons to deposit energy within the core, they should have kinetic energies on the order of a few MeV, as less energetic electrons will be stopped prior to the core and more energetic electrons will pass through the core without depositing much energy. Thus a quantitative understanding of the electron energy spectrum and how it responds to varied laser parameters is paramount for fast ignition. For the first time, this dissertation quantitatively investigates the acceleration of electrons using an ultra-high-contrast laser. Ultra-high-contrast lasers reduce the laser energy that reaches the target prior to the main pulse; drastically reducing the amount of preplasma. Experiments were performed in a cone-wire geometry relevant to fast ignition. These experiments irradiated the inner-tip of a Au cone with the laser and observed electrons that passed through a Cu wire attached to the outer-tip of the cone. The total emission of Kalpha x-rays is used as a diagnostic to infer the electron energy coupled into the wire. Imaging the x-ray emission allowed an effective path-length of electrons within the wire to be determined, which constrained the electron energy spectrum. Experiments were carried out on the ultra-high-contrast Trident laser

  11. Dosimetry of laser-accelerated electron beams used for in vitro cell irradiation experiments

    International Nuclear Information System (INIS)

    Richter, C.; Kaluza, M.; Karsch, L.; Schlenvoigt, H.-P.; Schürer, M.; Sobiella, M.; Woithe, J.; Pawelke, J.

    2011-01-01

    The dosimetric characterization of laser-accelerated electrons applied for the worldwide first systematic radiobiological in vitro cell irradiation will be presented. The laser-accelerated electron beam at the JeTi laser system has been optimized, monitored and controlled in terms of dose homogeneity, stability and absolute dose delivery. A combination of different dosimetric components were used to provide both an online beam as well as dose monitoring and a precise absolute dosimetry. In detail, the electron beam was controlled and monitored by means of an ionization chamber and an in-house produced Faraday cup for a defined delivery of the prescribed dose. Moreover, the precise absolute dose delivered to each cell sample was determined by an radiochromic EBT film positioned in front of the cell sample. Furthermore, the energy spectrum of the laser-accelerated electron beam was determined. As presented in a previous work of the authors, also for laser-accelerated protons a precise dosimetric characterization was performed that enabled initial radiobiological cell irradiation experiments with laser-accelerated protons. Therefore, a precise dosimetric characterization, optimization and control of laser-accelerated and therefore ultra-short pulsed, intense particle beams for both electrons and protons is possible, allowing radiobiological experiments and meeting all necessary requirements like homogeneity, stability and precise dose delivery. In order to fulfill the much higher dosimetric requirements for clinical application, several improvements concerning, i.e., particle energy and spectral shaping as well as patient safety are necessary.

  12. Directed Acceleration of Electrons from a Solid Surface by Sub-10-fs Laser Pulses

    International Nuclear Information System (INIS)

    Brandl, F.; Hidding, B.; Osterholz, J.; Hemmers, D.; Pretzler, G.; Karmakar, A.; Pukhov, A.

    2009-01-01

    Electrons have been accelerated from solid target surfaces by sub-10-fs laser pulses of 120 μJ energy which were focused to an intensity of 2x10 16 W/cm 2 . The electrons have a narrow angular distribution, and their observed energies exceed 150 keV. We show that these energies are not to be attributed to collective plasma effects but are mainly gained directly via repeated acceleration in the transient field pattern created by incident and reflected laser, alternating with phase-shift-generating scattering events in the solid.

  13. Production of a monoenergetic electron bunch in a self-injected laser-wakefield accelerator

    International Nuclear Information System (INIS)

    Chang, C.-L.; Hsieh, C.-T.; Ho, Y.-C.; Chen, Y.-S.; Lin, J.-Y.; Wang, J.; Chen, S.-Y.

    2007-01-01

    Production of a monoenergetic electron bunch in a self-injected laser-wakefield accelerator is investigated with a tomographic method which resolves the electron injection and acceleration processes. It is found that all the electrons in the monoenergetic electron bunch are injected at the same location in the plasma column and then accelerated with an acceleration gradient exceeding 2 GeV/cm. The injection position shifts with the position of pump-pulse focus, and no significant deceleration is observed for the monoenergetic electron bunch after it reaches the maximum energy. The results are consistent with the model of transverse wave breaking and beam loading for the injection of monoenergetic electrons. The tomographic method adds a crucial dimension to the whole array of existing diagnostics for laser beams, plasma waves, and electron beams. With this method the details of the underlying physical processes in laser-plasma interactions can be resolved and compared directly to particle-in-cell simulations

  14. Electron beam dynamics in the long-pulse, high-current DARHT-II linear induction accelerator

    International Nuclear Information System (INIS)

    Ekdahl, Carl A.; Abeyta, Epifanio O.; Aragon, Paul; Archuleta, Rita; Cook, Gerald; Dalmas, Dale; Esquibel, Kevin; Gallegos, Robert A.; Garnett, Robert; Harrison, James F.; Johnson, Jeffrey B.; Jacquez, Edward B.; Mccuistian, Brian T.; Montoya, Nicholas A.; Nath, Subrato; Nielsen, Kurt; Oro, David; Prichard, Benjamin; Rowton, Lawrence; Sanchez, Manolito; Scarpetti, Raymond; Schauer, Martin M.; Seitz, Gerald; Schulze, Martin; Bender, Howard A.; Broste, William B.; Carlson, Carl A.; Frayer, Daniel K.; Johnson, Douglas E.; Tom, C.Y.; Williams, John; Hughes, Thomas; Anaya, Richard; Caporaso, George; Chambers, Frank; Chen, Yu-Jiuan; Falabella, Steve; Guethlein, Gary; Raymond, Brett; Richardson, Roger; Trainham, C.; Watson, Jim; Weir, John; Genoni, Thomas; Toma, Carsten

    2009-01-01

    The DARHT-II linear induction accelerator (LIA) now accelerates 2-kA electron beams to more than 17 MeV. This LIA is unique in that the accelerated current pulse width is greater than 2 microseconds. This pulse has a flat-top region where the final electron kinetic energy varies by less than 1% for more than 1.5 microseconds. The long risetime of the 6-cell injector current pulse is 0.5 (micro)s, which can be scraped off in a beam-head cleanup zone before entering the 68-cell main accelerator. We discuss our experience with tuning this novel accelerator; and present data for the resulting beam transport and dynamics. We also present beam stability data, and relate these to previous stability experiments at lower current and energy.

  15. Vacuum electron acceleration by coherent dipole radiation

    International Nuclear Information System (INIS)

    Troha, A.L.; Van Meter, J.R.; Landahl, E.C.; Alvis, R.M.; Hartemann, F.V.; Troha, A.L.; Van Meter, J.R.; Landahl, E.C.; Alvis, R.M.; Li, K.; Luhmann, N.C. Jr.; Hartemann, F.V.; Unterberg, Z.A.; Kerman, A.K.

    1999-01-01

    The validity of the concept of laser-driven vacuum acceleration has been questioned, based on an extrapolation of the well-known Lawson-Woodward theorem, which stipulates that plane electromagnetic waves cannot accelerate charged particles in vacuum. To formally demonstrate that electrons can indeed be accelerated in vacuum by focusing or diffracting electromagnetic waves, the interaction between a point charge and coherent dipole radiation is studied in detail. The corresponding four-potential exactly satisfies both Maxwell's equations and the Lorentz gauge condition everywhere, and is analytically tractable. It is found that in the far-field region, where the field distribution closely approximates that of a plane wave, we recover the Lawson-Woodward result, while net acceleration is obtained in the near-field region. The scaling of the energy gain with wave-front curvature and wave amplitude is studied systematically. copyright 1999 The American Physical Society

  16. Electron beam potential measurements on an inductive-store, opening-switch accelerator

    International Nuclear Information System (INIS)

    Riordan, J.C.; Goyer, J.R.; Kortbawi, D.; Meachum, J.S.; Mendenhall, R.S.; Roth, I.S.

    1993-01-01

    Direct measurement of the accelerating potential in a relativistic electron beam accelerator is difficult, particularly when the diode is downstream from a plasma opening switch. An indirect potential measurement can be obtained from the high energy tail of the bremsstrahlung spectrum generated as the electron beam strikes the anode. The authors' time-resolved spectrometer contains 7 silicon pin diode detectors filtered with 2 to 15 mm of lead to span an electron energy range of 0.5 to 2 MeV. A Monte-Carlo transport code was used to provide calibration curves, and the resulting potential measurements have been confirmed in experiments on the PITHON accelerator. The spectrometer has recently been deployed on PM1, an inductive-store, opening-switch testbed. The diode voltage measurements from the spectrometer are in good agreement with the diode voltage measured upstream and corrected using transmission line relations. The x-ray signal and spectral voltage rise 10 ns later than the corrected electrical voltage, however, indicating plasma motion between the opening switch and the diode

  17. Neutron fluence in a 18 MeV Electron Accelerator for Therapy

    International Nuclear Information System (INIS)

    Paredes G, L.C.

    2001-01-01

    An investigation was made on the theoretical fundamentals for the determination of the neutron fluence in a linear electron accelerator for radiotherapy applications and the limit values of leakage neutron radiation established by guidelines and standards in radiation protection for these type of accelerators. This investigation includes the following parts: a) Exhaustive bibliographical review on the topics mentioned above, in order to combine and to update the necessary basic information to facilitate the understanding of this subject; b) Analysis of the accelerator operation and identification of its main components, specially in the accelerator head; c) Study of different types of targets and its materials for the Bremsstrahlung production which is based on the electron initial energy, the thickness of the target, and its angular distribution and energy, which influences in the neutron generation by means of the photonuclear and electro disintegration reactions; d) Analysis of the neutron yield based on the target type and its thickness, the energy of electrons and photons; e) Analysis of the neutron energy spectra generated in the accelerator head, inside and outside the treatment room; f) Study of the dosimetry fundamentals for neutron and photon mixed fields, the dosimeter selection criteria and standards applied for these applications, specially the Panasonic U D-809 thermoluminescent dosemeter and C R-39 nuclear track dosimeter; g) Theoretical calculation of the neutron yield using a simplified geometric model for the accelerator head with spherical cell, which considers the target, primary collimator, flattener filter, movable collimators and the head shielding as the main components for radiation production. The cases with W and Pb shielding for closed movable collimators and an irradiation field of 20 x 20 cm 2 were analyzed and, h) Experimental evaluation of the leakage neutron radiation from the patient and head planes, observing that the accelerator

  18. An experimental program for collective acceleration of ions using intense relativistic electron beams

    International Nuclear Information System (INIS)

    Vijayan, T.; Raychowdhury, P.; Iyengar, S.K.

    1992-01-01

    A program of collective ion acceleration using intense relativistic electron beam (IREB) of 0.25-1MeV, 6-80kA, 60ns on the Kilo Ampere Linear Injector (KALI) systems to accelerate light and heavy ions to high energies approaching GeV with currents over tens of amperes, is envisaged in this report. The accelerator will make use of the intense space-charge field of electron beam in vacuum for accelerating ions which are injected into it. For ion injection, various alternatives, such as, localized gas puff, dielectric insert, laser plasma, etc. have been considered as present and long-term objectives. Among the variety of diagnostic methods chosen for characterizing the accelerated ions include range-energy in foil, CR-39 track detector, nuclear activation technique and time-of-flight for energy and species determination; ion Faraday cup for current measurement; and Thomson parabola analyzer for determining the post-acceleration charge-state. In the proposed MAHAKALI collective accelerator, protons of energy over 10 MeV and higher charge state metal ions around a GeV are predicted using a REB of 1MeV, 30kA, 60ns from KALI-5000. In present experiments using KALI-200 with REB parameters of 250keV, 60kA, 80ns, protons over a MeV and carbon and fluorine ions respectively for 12MeV and 16MeV in significant currents have been accelerated. (author). 35 refs., figs., tabs

  19. Radiation belt electron acceleration during the 17 March 2015 geomagnetic storm: Observations and simulations

    International Nuclear Information System (INIS)

    Li, W.; Ma, Q.; Thorne, R. M.; Bortnik, J.; Zhang, X.-J.

    2016-01-01

    Various physical processes are known to cause acceleration, loss, and transport of energetic electrons in the Earth's radiation belts, but their quantitative roles in different time and space need further investigation. During the largest storm over the past decade (17 March 2015), relativistic electrons experienced fairly rapid acceleration up to ~7 MeV within 2 days after an initial substantial dropout, as observed by Van Allen Probes. In the present paper, we evaluate the relative roles of various physical processes during the recovery phase of this large storm using a 3-D diffusion simulation. By quantitatively comparing the observed and simulated electron evolution, we found that chorus plays a critical role in accelerating electrons up to several MeV near the developing peak location and produces characteristic flat-top pitch angle distributions. By only including radial diffusion, the simulation underestimates the observed electron acceleration, while radial diffusion plays an important role in redistributing electrons and potentially accelerates them to even higher energies. Moreover, plasmaspheric hiss is found to provide efficient pitch angle scattering losses for hundreds of keV electrons, while its scattering effect on > 1 MeV electrons is relatively slow. Although an additional loss process is required to fully explain the overestimated electron fluxes at multi-MeV, the combined physical processes of radial diffusion and pitch angle and energy diffusion by chorus and hiss reproduce the observed electron dynamics remarkably well, suggesting that quasi-linear diffusion theory is reasonable to evaluate radiation belt electron dynamics during this big storm.

  20. Preliminary investigations on high energy electron beam tomography

    Energy Technology Data Exchange (ETDEWEB)

    Baertling, Yves; Hoppe, Dietrich; Hampel, Uwe

    2010-12-15

    In computed tomography (CT) cross-sectional images of the attenuation distribution within a slice are created by scanning radiographic projections of an object with a rotating X-ray source detector compound and subsequent reconstruction of the images from these projection data on a computer. CT can be made very fast by employing a scanned electron beam instead of a mechanically moving X-ray source. Now this principle was extended towards high-energy electron beam tomography with an electrostatic accelerator. Therefore a dedicated experimental campaign was planned and carried out at the Budker Institute of Nuclear Physics (BINP), Novosibirsk. There we investigated the capabilities of BINP's accelerators as an electron beam generating and scanning unit of a potential high-energy electron beam tomography device. The setup based on a 1 MeV ELV-6 (BINP) electron accelerator and a single detector. Besides tomographic measurements with different phantoms, further experiments were carried out concerning the focal spot size and repeat accuracy of the electron beam as well as the detector's response time and signal to noise ratio. (orig.)

  1. Proposed Physics Experiments for Laser-Driven Electron Linear Acceleration in a Dielectric Loaded Vacuum, Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Byer, Robert L. [Stanford Univ., CA (United States). Dept. of Applied Physics. Edward L. Ginzton Lab.

    2016-07-08

    This final report summarizes the last three years of research on the development of advanced linear electron accelerators that utilize dielectric wave-guide vacuum channels pumped by high energy laser fields to accelerate beams of electrons.

  2. SEE induced in SRAM operating in a superconducting electron linear accelerator environment

    Science.gov (United States)

    Makowski, D.; Mukherjee, Bhaskar; Grecki, M.; Simrock, Stefan

    2005-02-01

    Strong fields of bremsstrahlung photons and photoneutrons are produced during the operation of high-energy electron linacs. Therefore, a mixed gamma and neutron radiation field dominates the accelerators environment. The gamma radiation induced Total Ionizing Dose (TID) effect manifests the long-term deterioration of the electronic devices operating in accelerator environment. On the other hand, the neutron radiation is responsible for Single Event Effects (SEE) and may cause a temporal loss of functionality of electronic systems. This phenomenon is known as Single Event Upset (SEU). The neutron dose (KERMA) was used to scale the neutron induced SEU in the SRAM chips. Hence, in order to estimate the neutron KERMA conversion factor for Silicon (Si), dedicated calibration experiments using an Americium-Beryllium (241Am/Be) neutron standard source was carried out. Single Event Upset (SEU) influences the short-term operation of SRAM compared to the gamma induced TID effect. We are at present investigating the feasibility of an SRAM based real-time beam-loss monitor for high-energy accelerators utilizing the SEU caused by fast neutrons. This paper highlights the effects of gamma and neutron radiations on Static Random Access Memory (SRAM), placed at selected locations near the Superconducting Linear Accelerator driving the Vacuum UV Free Electron Laser (VUVFEL) of DESY.

  3. Electron Acceleration by High Power Radio Waves in the Ionosphere

    Science.gov (United States)

    Bernhardt, Paul

    2012-10-01

    At the highest ERP of the High Altitude Auroral Research Program (HAARP) facility in Alaska, high frequency (HF) electromagnetic (EM) waves in the ionosphere produce artificial aurora and electron-ion plasma layers. Using HAARP, electrons are accelerated by high power electrostatic (ES) waves to energies >100 times the thermal temperature of the ambient plasma. These ES waves are driven by decay of the pump EM wave tuned to plasma resonances. The most efficient acceleration process occurs near the harmonics of the electron cyclotron frequency in earth's magnetic field. Mode conversion plays a role in transforming the ES waves into EM signals that are recorded with ground receivers. These diagnostic waves, called stimulated EM emissions (SEE), show unique resonant signatures of the strongest electron acceleration. This SEE also provides clues about the ES waves responsible for electron acceleration. The electron gas is accelerated by high frequency modes including Langmuir (electron plasma), upper hybrid, and electron Bernstein waves. All of these waves have been identified in the scattered EM spectra as downshifted sidebands of the EM pump frequency. Parametric decay is responsible low frequency companion modes such as ion acoustic, lower hybrid, and ion Bernstein waves. The temporal evolution of the scattered EM spectrum indicates development of field aligned irregularities that aid the mode conversion process. The onset of certain spectral features is strongly correlated with glow plasma discharge structures that are both visible with the unaided eye and detectable using radio backscatter techniques at HF and UHF frequencies. The primary goals are to understand natural plasma layers, to study basic plasma physics in a unique ``laboratory with walls,'' and to create artificial plasma structures that can aid radio communications.

  4. Future Accelerator Challenges in Support of High-Energy Physics

    International Nuclear Information System (INIS)

    Zisman, Michael S.; Zisman, M.S.

    2008-01-01

    Historically, progress in high-energy physics has largely been determined by development of more capable particle accelerators. This trend continues today with the imminent commissioning of the Large Hadron Collider at CERN, and the worldwide development effort toward the International Linear Collider. Looking ahead, there are two scientific areas ripe for further exploration--the energy frontier and the precision frontier. To explore the energy frontier, two approaches toward multi-TeV beams are being studied, an electron-positron linear collider based on a novel two-beam powering system (CLIC), and a Muon Collider. Work on the precision frontier involves accelerators with very high intensity, including a Super-BFactory and a muon-based Neutrino Factory. Without question, one of the most promising approaches is the development of muon-beam accelerators. Such machines have very high scientific potential, and would substantially advance the state-of-the-art in accelerator design. The challenges of the new generation of accelerators, and how these can be accommodated in the accelerator design, are described. To reap their scientific benefits, all of these frontier accelerators will require sophisticated instrumentation to characterize the beam and control it with unprecedented precision

  5. Future Accelerator Challenges in Support of High-Energy Physics

    Energy Technology Data Exchange (ETDEWEB)

    Zisman, Michael S.; Zisman, M.S.

    2008-05-03

    Historically, progress in high-energy physics has largely been determined by development of more capable particle accelerators. This trend continues today with the imminent commissioning of the Large Hadron Collider at CERN, and the worldwide development effort toward the International Linear Collider. Looking ahead, there are two scientific areas ripe for further exploration--the energy frontier and the precision frontier. To explore the energy frontier, two approaches toward multi-TeV beams are being studied, an electron-positron linear collider based on a novel two-beam powering system (CLIC), and a Muon Collider. Work on the precision frontier involves accelerators with very high intensity, including a Super-BFactory and a muon-based Neutrino Factory. Without question, one of the most promising approaches is the development of muon-beam accelerators. Such machines have very high scientific potential, and would substantially advance the state-of-the-art in accelerator design. The challenges of the new generation of accelerators, and how these can be accommodated in the accelerator design, are described. To reap their scientific benefits, all of these frontier accelerators will require sophisticated instrumentation to characterize the beam and control it with unprecedented precision.

  6. Production of high-quality electron bunches by dephasing and beam loading in channeled and unchanneled laser plasma accelerators

    International Nuclear Information System (INIS)

    Geddes, C.G.R.; Toth, Cs.; Tilborg, J. van; Esarey, E.; Schroeder, C.B.; Bruhwiler, D.; Nieter, C.; Cary, J.; Leemans, W.P.

    2005-01-01

    High-quality electron beams, with a few 10 9 electrons within a few percent of the same energy above 80 MeV, were produced in a laser wakefield accelerator by matching the acceleration length to the length over which electrons were accelerated and outran (dephased from) the wake. A plasma channel guided the drive laser over long distances, resulting in production of the high-energy, high-quality beams. Unchanneled experiments varying the length of the target plasma indicated that the high-quality bunches are produced near the dephasing length and demonstrated that channel guiding was more stable and efficient than relativistic self-guiding. Consistent with these data, particle-in-cell simulations indicate production of high-quality electron beams when trapping of an initial bunch of electrons suppresses further injection by loading the wake. The injected electron bunch is then compressed in energy by dephasing, when the front of the bunch begins to decelerate while the tail is still accelerated

  7. Supersonic micro-jets and their application to few-cycle laser-driven electron acceleration

    International Nuclear Information System (INIS)

    Schmid, Karl

    2009-01-01

    This thesis covers the few-cycle laser-driven acceleration of electrons in a laser-generated plasma. The laser system employed in this work is a new development based on optical parametric chirped pulse amplification and is the only multi-TW few-cycle laser in the world. In the experiment, the laser beam is focused onto a supersonic helium gas jet which leads to the formation of a plasma channel. The laser pulse, having an intensity of 10 19 W/cm 2 propagates through the plasma with an electron density of 2 x 10 19 cm -3 and forms via a highly nonlinear interaction a strongly anharmonic plasma wave. The amplitude of the wave is so large that the wave breaks, thereby injecting electrons from the background plasma into the accelerating phase. The energy transfer from the laser pulse to the plasma is so strong that the maximum propagation distance is limited to the 100 m range. Therefore, gas jets specifically tuned to these requirements have to be employed. The properties of microscopic supersonic gas jets are thoroughly analyzed in this work. Based on numeric flow simulation, this study encompasses several extensive parameter studies that illuminate all relevant features of supersonic flows in microscopic gas nozzles. This allowed the optimized design of de Laval nozzles with exit diameters ranging from 150 μm to 3 mm. The employment of these nozzles in the experiment greatly improved the electron beam quality. After these optimizations, the laser-driven electron accelerator now yields monoenergetic electron pulses with energies up to 50 MeV and charges between one and ten pC. The electron beam has a typical divergence of 5 mrad and comprises an energy spectrum that is virtually free from low energetic background. The electron pulse duration could not yet be determined experimentally but simulations point towards values in the range of 1 fs. The acceleration gradient is estimated from simulation and experiment to be approximately 0.5 TV/m. The electron accelerator

  8. Supersonic micro-jets and their application to few-cycle laser-driven electron acceleration

    Energy Technology Data Exchange (ETDEWEB)

    Schmid, Karl

    2009-07-23

    This thesis covers the few-cycle laser-driven acceleration of electrons in a laser-generated plasma. The laser system employed in this work is a new development based on optical parametric chirped pulse amplification and is the only multi-TW few-cycle laser in the world. In the experiment, the laser beam is focused onto a supersonic helium gas jet which leads to the formation of a plasma channel. The laser pulse, having an intensity of 10{sup 19} W/cm{sup 2} propagates through the plasma with an electron density of 2 x 10{sup 19} cm{sup -3} and forms via a highly nonlinear interaction a strongly anharmonic plasma wave. The amplitude of the wave is so large that the wave breaks, thereby injecting electrons from the background plasma into the accelerating phase. The energy transfer from the laser pulse to the plasma is so strong that the maximum propagation distance is limited to the 100 m range. Therefore, gas jets specifically tuned to these requirements have to be employed. The properties of microscopic supersonic gas jets are thoroughly analyzed in this work. Based on numeric flow simulation, this study encompasses several extensive parameter studies that illuminate all relevant features of supersonic flows in microscopic gas nozzles. This allowed the optimized design of de Laval nozzles with exit diameters ranging from 150 {mu}m to 3 mm. The employment of these nozzles in the experiment greatly improved the electron beam quality. After these optimizations, the laser-driven electron accelerator now yields monoenergetic electron pulses with energies up to 50 MeV and charges between one and ten pC. The electron beam has a typical divergence of 5 mrad and comprises an energy spectrum that is virtually free from low energetic background. The electron pulse duration could not yet be determined experimentally but simulations point towards values in the range of 1 fs. The acceleration gradient is estimated from simulation and experiment to be approximately 0.5 TV/m. The

  9. Few femtosecond, few kilo-ampere electron bunch produced by a laser-plasma accelerator

    International Nuclear Information System (INIS)

    Lundh, O.; Lim, J.; Rechatin, C.; Ammoura, L.; Goddet, J.P.; Malka, V.; Faure, J.; Ben-Ismail, A.; Davoine, X.; Lefebvre, E.; Gallot, G.

    2011-01-01

    Particle accelerators driven by the interaction of ultra-intense and ultrashort laser pulses with a plasma can generate accelerating electric fields of several hundred giga-volts per meter and deliver high-quality electron beams with low energy spread, low emittance and up to 1 GeV peak energy. Moreover, it is expected they may soon be able to produce bursts of electrons shorter than those produced by conventional particle accelerators, down to femtosecond durations and less. Here we present wide-band spectral measurements of coherent transition radiation which we use for temporal characterization. Our analysis shows that the electron beam, produced using controlled optical injection, contains a temporal feature that can be identified as a 15 pC, 1.4-1.8 fs electron bunch (root mean square) leading to a peak current of 3-4 kA depending on the bunch shape. We anticipate that these results will have a strong impact on emerging applications such as short-pulse and short-wavelength radiation sources, and will benefit the realization of laboratory-scale free-electron lasers. (authors)

  10. Physical design of 9 MeV travelling wave electron linac accelerating tube

    International Nuclear Information System (INIS)

    Chen Huaibi; Ding Xiaodong; Lin Yuzheng

    2000-01-01

    An accelerating tube is described. It is a part of an accelerator used for inspection of vehicle cargoes in rail cars, trucks, shipping containers, or airplanes in customs. A klystron with power of 4 MW and frequency of 2856 MHz will be applied to supply microwave power. The electrons can be accelerated by a travelling wave in the accelerating tube about 220 cm long, with a buncher whose capture efficiency is more than 80%. Energy of electrons after travelling through the tube can reach 9 MeV (pulse current intensity 170 mA) or 6 MeV (pulse current intensity 300 mA). Physical design of the accelerating tube, including the calculations of longitudinal particle dynamics, structure parameter and working character is carried out

  11. Electron beam acceleration and compression for short wavelength FELs

    International Nuclear Information System (INIS)

    Raubenheimer, T.O.

    1994-11-01

    A single pass UV or X-ray FEL will require a low emittance electron beam with high peak current and relatively high beam energy, a few hundred MeV to many GeV. To achieve the necessary peak current and beam energy, the beams must be bunch compressed and they must be accelerated in long transport lines where dispersive and wakefield emittance dilutions are important. In this paper, we will describe the sources and significance of the dilutions during acceleration, bunch compression, and transport through the undulator. In addition, we will discuss sources of jitter, especially effects arising from the bunch compressions, and the possible cancellation techniques

  12. The chirped-pulse inverse free-electron laser: A high-gradient vacuum laser accelerator

    International Nuclear Information System (INIS)

    Hartemann, F.V.; Landahl, E.C.; Troha, A.L.; Van Meter, J.R.; Baldis, H.A.; Freeman, R.R.; Luhmann, N.C. Jr.; Song, L.; Kerman, A.K.; Yu, D.U.

    1999-01-01

    The inverse free-electron laser (IFEL) interaction is studied theoretically and computationally in the case where the drive laser intensity approaches the relativistic regime, and the pulse duration is only a few optical cycles long. The IFEL concept has been demonstrated as a viable vacuum laser acceleration process; it is shown here that by using an ultrashort, ultrahigh-intensity drive laser pulse, the IFEL interaction bandwidth and accelerating gradient are increased considerably, thus yielding large energy gains. Using a chirped pulse and negative dispersion focusing optics allows one to take further advantage of the laser optical bandwidth and produce a chromatic line focus maximizing the gradient. The combination of these novel ideas results in a compact vacuum laser accelerator capable of accelerating picosecond electron bunches with a high gradient (GeV/m) and very low energy spread. copyright 1999 American Institute of Physics

  13. High Energy Electron Dosimetry by Alanine/ESR Spectroscopy

    International Nuclear Information System (INIS)

    Chu, Sung Sil

    1989-01-01

    Dosimetry based on electron spin resonance(ESR) analysis of radiation induced free radicals in amino acids is relevant to biological dosimetry applications. Alanine detectors are without walls and are tissue equivalent. Therefore, alanine ESR dosimetry looks promising for use in the therapy level. The dose range of the alanine/ESR dosimetry system can be extended down to l Gy. In a water phantom the absorbed dose of electrons generated by a medical linear accelerator of different initial energies (6-21 MeV) and therapeutic dose levels(1-60 Gy) was measured. Furthermore, depth dose measurements carried out with alanine dosimeters were compared with ionization chamber measurements. As the results, the measured absorbed doses for shallow depth of initial electron energies above 15 MeV were higher by 2-5% than those calculated by nominal energy CE factors. This seems to be caused by low energy scattered beams generated from the scattering foil and electron cones of beam projecting device in medical linear accelerator

  14. Ultra high energy electrons powered by pulsar rotation.

    Science.gov (United States)

    Mahajan, Swadesh; Machabeli, George; Osmanov, Zaza; Chkheidze, Nino

    2013-01-01

    A new mechanism of particle acceleration, driven by the rotational slow down of the Crab pulsar, is explored. The rotation, through the time dependent centrifugal force, can efficiently excite unstable Langmuir waves in the electron-positron (hereafter e(±)) plasma of the star magnetosphere. These waves, then, Landau damp on electrons accelerating them in the process. The net transfer of energy is optimal when the wave growth and the Landau damping times are comparable and are both very short compared to the star rotation time. We show, by detailed calculations, that these are precisely the conditions for the parameters of the Crab pulsar. This highly efficient route for energy transfer allows the electrons in the primary beam to be catapulted to multiple TeV (~ 100 TeV) and even PeV energy domain. It is expected that the proposed mechanism may, unravel the puzzle of the origin of ultra high energy cosmic ray electrons.

  15. Small-sized accelerating tube for electron acceleration to 500 keV at pulse duration of 2 ns

    International Nuclear Information System (INIS)

    Pavlovskaya, N.G.; Ehl'yash, S.L.; Dron', N.A.; Sloeva, G.N.

    1978-01-01

    The design and characteristics (current, voltage, current density, electron beam structure, energy spectrum, and dose rate) of a soldered small-size two-electrode 600 kV accelerating tube are considered. A six-stage Arkadiev-Marx generator is the pulse high-voltage supply of nanosecond duration. When using a cathode (diameter of 8 mm) made of tantalum foil 0.02 mm thick and with interelectrode gap of 10 mm, the amplitude of the electron beam current beyond the beryllium anode equals to 1040 A under maximum voltage of 490 kV, current pulse duration of 2 ns, number of electrons is 10 13 . The increased electron density on the anode in a spot of 4 mm in diameter is observed; the current density in the spot reaches 1 kA/cm 2 . The electron energy in the beam beyond the anode is as much as 0.6-0.8 J per pulse, and the dose rate near the outer surface of the outlet window is 10 14 -10 15 rad/s. The use of an intensifying oil spark gap is shown to increase radiation hardness. The accelerating tube provides more than 10 5 shots in a single-switching mode

  16. Accelerators for atomic energy research

    International Nuclear Information System (INIS)

    Shibata, Tokushi

    1999-01-01

    The research and educational activities accomplished using accelerators for atomic energy research were studied. The studied items are research subjects, facility operation, the number of master theses and doctor theses on atomic energy research using accelerators and the future role of accelerators in atomic energy research. The strategy for promotion of the accelerator facility for atomic energy research is discussed. (author)

  17. Electron acceleration by CO/sub 2/ laser

    International Nuclear Information System (INIS)

    Fujita, H.; Kitagawa, Y.; Daido, H.

    1986-01-01

    Experiments on electron acceleration have been performed by LEKKO VIII CO/sub 2/ laser system. The laser light was focused by an off-axis parabolic mirror with the F-number of 1.5 and irradiated to thin foil and pipe targets in order to obtain uniform underdense plasmas. Energy spectrum of electrons was measured by an electron spectrometer in the range of 0.3-1.1 MeV. In the single frequency case, electrons up to 1 MeV were observed in the direction of the laser axis for the laser intensity above 1.6 x 10/sup 14/ W/cm/sup 2/ which was equal to the estimated threshold for forward Raman scattering. Amount of high energy electrons depended on the interaction length and the background hot electron temperature. More electrons could resonate with the plasma wave for the higher hot electron temperature. This was confirmed by particle simulation. In most experiments, the plasma density was estimated of about 0.1 n/sub c/. When the plasma density was reduced to 0.01 n/sub c/ using pre-pulse, high energy electrons were not observed because of the low background hot electron temperature and the higher instability threshold. In the two frequency case, energetic electron beam injection is planned for efficient coupling with fast plasma wave. Pipe target seems to be hopeful because 1) the laser light is confined by the plasma fiber and 2) the phase velocity of the plasma wave is controlled by the transverse mode

  18. Simulation studies of electron acceleration by ion ring distributions in solar flares

    International Nuclear Information System (INIS)

    McClements, K.G.; Bingham, R.; Su, J.J.; Dawson, J.M.; Spicer, D.S.

    1990-07-01

    Using a 21/2-D fully relativistic electromagnetic particle-in-cell code (PIC) we have investigated a potential electron acceleration mechanism in solar flares. The free energy is provided by ions which have a ring velocity distribution about the magnetic field direction. Ion rings may be produced by perpendicular shocks, which could in turn be generated by the super-Alfvenic motion of magnetic flux tubes emerging from the photosphere or by coronal mass ejections (CMEs). Such ion distributions are known to be unstable to the generation of lower hybrid waves, which have phase velocities in excess of the electron thermal speed parallel to the field and can therefore resonantly accelerate electrons in that direction. The simulations show the transfer of perpendicular ion energy to energetic electrons via lower hybrid wave turbulence. With plausible ion ring velocities, the process can account for the observationally inferred fluxes and energies of non-thermal electrons during the impulsive phase of flares. Our results also show electrostatic wave generation close to the plasma frequency: we suggest that this is due to bump-in-tail instability of the electron distribution. (author)

  19. Ultra-High-Contrast Laser Acceleration of Relativistic Electrons in Solid Targets

    Energy Technology Data Exchange (ETDEWEB)

    Higginson, Drew Pitney [Univ. of California, San Diego, CA (United States)

    2013-01-01

    The cone-guided fast ignition approach to Inertial Con nement Fusion requires laser-accelerated relativistic electrons to deposit kilojoules of energy within an imploded fuel core to initiate fusion burn. One obstacle to coupling electron energy into the core is the ablation of material, known as preplasma, by laser energy proceeding nanoseconds prior to the main pulse. This causes the laser-absorption surface to be pushed back hundreds of microns from the initial target surface; thus increasing the distance that electrons must travel to reach the imploded core. Previous experiments have shown an order of magnitude decrease in coupling into surrogate targets when intentionally increasing the amount of preplasma. Additionally, for electrons to deposit energy within the core, they should have kinetic energies on the order of a few MeV, as less energetic electrons will be stopped prior to the core and more energetic electrons will pass through the core without depositing much energy. Thus a quantitative understanding of the electron energy spectrum and how it responds to varied laser parameters is paramount for fast ignition. For the rst time, this dissertation quantitatively investigates the acceleration of electrons using an ultra-high-contrast laser. Ultra-high-contrast lasers reduce the laser energy that reaches the target prior to the main pulse; drastically reducing the amount of preplasma. Experiments were performed in a cone-wire geometry relevant to fast ignition. These experiments irradiated the inner-tip of a Au cone with the laser and observed electrons that passed through a Cu wire attached to the outer-tip of the cone. The total emission of K x-rays is used as a diagnostic to infer the electron energy coupled into the wire. Imaging the x-ray emission allowed an e ective path-length of electrons within the wire to be determined, which constrained the electron energy spectrum. Experiments were carried out on the ultra-high-contrast Trident laser at Los

  20. Radiation safety aspects of high energy particle accelerators

    International Nuclear Information System (INIS)

    Subbaiah, K.V.

    2007-01-01

    High-energy accelerators are widely used for various applications in industry, medicine and research. These accelerators are capable of accelerating both ions and electrons over a wide range of energy and subsequently are made to impinge on the target materials. Apart from generating intended reactions in the target, these projectiles can also generate highly penetrating radiations such as gamma rays and neutrons. Over exposure to these radiations will cause deleterious effects on the living beings. Various steps taken to protect workers and general public from these harmful radiations is called radiation safety. The primary objective in establishing permissible values for occupational workers is to keep the radiation worker well below a level at which adverse effects are likely to be observed during one's life time. Another objective is to minimize the incidence of genetic effects for the population as a whole. Today's presentation on radiation safety of accelerators will touch up on the following sub-topics: Types of particle accelerators and their applications; AERB directives on dose limits; Radiation Source term of accelerators; Shielding Design-Use of Transmission curves and Tenth Value layers; Challenges for accelerator health physicists

  1. Change in operating parameters of the Continuous Electron Beam Accelerator Facility and Free Electron Laser, Thomas Jefferson National Accelerator Facility, Newport News, Virginia

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-10-01

    In this environmental assessment (EA), the US Department of Energy (DOE) reports the results of an analysis of the potential environmental impacts from a proposed change in operating parameters of the Continuous Electron Beam Accelerator Facility (CEBAF), and operation of the Free Electron Laser (FEL) facility beyond the initial demonstration period. With this proposal, DOE intends to increase CEBAF operating range from its current operating maximum beam energy of 4.0 GeV [giga-(billion) electron volts] to 8.0 GeV at a beam power of no greater than 1,000 kW [1 megawatt (MW)], its maximum attainable level, based on current technology and knowledge, without significant, costly equipment modifications. DOE has prepared an EA for this action to determine the potential for adverse impacts from operation of CEBAF and the FEL at the proposed levels. Changing the operating parameters of CEBAF would require no new major construction and minor modifications to the accelerator, its support systems, the FEL, and onsite utility systems. Modifications and performance improvements would be made to (1) the accelerator housed in the underground tunnels, (2) its support systems located in the above ground service buildings, and (3) the water and equipment cooling systems both in the tunnel and at the ground surface. All work would be performed on previously disturbed land and in, on, or adjacent to existing buildings, structures, and equipment. With the proposed action, the recently constructed FEL facility at the Jefferson Lab would operate in concert with CEBAF beyond its demonstration period and up to its maximum effective electron beam power level of 210 kW. In this EA, DOE evaluates the impacts of the no-action alternative and the proposed action alternative. Alternatives considered, but dismissed from further evaluation, were the use of another accelerator facility and the use of another technology.

  2. Change in operating parameters of the Continuous Electron Beam Accelerator Facility and Free Electron Laser, Thomas Jefferson National Accelerator Facility, Newport News, Virginia

    International Nuclear Information System (INIS)

    1997-10-01

    In this environmental assessment (EA), the US Department of Energy (DOE) reports the results of an analysis of the potential environmental impacts from a proposed change in operating parameters of the Continuous Electron Beam Accelerator Facility (CEBAF), and operation of the Free Electron Laser (FEL) facility beyond the initial demonstration period. With this proposal, DOE intends to increase CEBAF operating range from its current operating maximum beam energy of 4.0 GeV [giga-(billion) electron volts] to 8.0 GeV at a beam power of no greater than 1,000 kW [1 megawatt (MW)], its maximum attainable level, based on current technology and knowledge, without significant, costly equipment modifications. DOE has prepared an EA for this action to determine the potential for adverse impacts from operation of CEBAF and the FEL at the proposed levels. Changing the operating parameters of CEBAF would require no new major construction and minor modifications to the accelerator, its support systems, the FEL, and onsite utility systems. Modifications and performance improvements would be made to (1) the accelerator housed in the underground tunnels, (2) its support systems located in the above ground service buildings, and (3) the water and equipment cooling systems both in the tunnel and at the ground surface. All work would be performed on previously disturbed land and in, on, or adjacent to existing buildings, structures, and equipment. With the proposed action, the recently constructed FEL facility at the Jefferson Lab would operate in concert with CEBAF beyond its demonstration period and up to its maximum effective electron beam power level of 210 kW. In this EA, DOE evaluates the impacts of the no-action alternative and the proposed action alternative. Alternatives considered, but dismissed from further evaluation, were the use of another accelerator facility and the use of another technology

  3. Laser wakefield electron acceleration. A novel approach employing supersonic microjets and few-cycle laser pulses

    International Nuclear Information System (INIS)

    Schmid, Karl

    2011-01-01

    This thesis covers the few-cycle laser-driven acceleration of electrons in a laser-generated plasma. This process, known as laser wakefield acceleration (LWFA), relies on strongly driven plasma waves for the generation of accelerating gradients in the vicinity of several 100 GV/m, a value four orders of magnitude larger than that attainable by conventional accelerators. This thesis demonstrates that laser pulses with an ultrashort duration of 8 fs and a peak power of 6 TW allow the production of electron energies up to 50 MeV via LWFA. The special properties of laser accelerated electron pulses, namely the ultrashort pulse duration, the high brilliance, and the high charge density, open up new possibilities in many applications of these electron beams. (orig.)

  4. Use of electron accelerators in food irradiation

    International Nuclear Information System (INIS)

    Sanyal, Bhaskar

    2013-01-01

    Preservation of food by ionizing radiations involves controlled application of energy of radiation to agricultural commodities, foods and food ingredients, for improving storage life, hygiene and safety. Insects and microbes cause major economic losses to stored crops. Many of our food products are contaminated with diseases causing germs and toxin producing molds. Without improvement in microbial quality and getting properly treated to overcome quarantine barriers our agricultural products cannot get international markets. In this respect electron accelerators have immense potential in commercial radiation processing of foods. Both low and high dose applications with increased process rates can be achieved using accelerators to cover a wide spectrum of food commodities approved for commercial radiation processing as per the recent gazette notification under Atomic Energy (Radiation Processing of Food and Allied Products) Rule, 2012. The effectiveness of processing of food by ionizing radiation depends on proper delivery of absorbed dose and its reliable measurement. For food destined for international trade, it is important that the dosimetry used for dose determination is carried out accurately and that the process is monitored in accordance with the internationally accepted procedures. Experiments using alanine-EPR system were carried out to optimize the process parameters of 10 MeV electron beam for commercial irradiation of food. Different food commodities namely, mango, potato and rawa (semolina) were irradiated to measure the absorbed dose distribution. The actual depth dose profile in food products and useful scan width of the electron beam were determined for commercial radiation processing of food using electron beam. (author)

  5. Effects of laser-polarization and wiggler magnetic fields on electron acceleration in laser-cluster interaction

    Science.gov (United States)

    Singh Ghotra, Harjit; Kant, Niti

    2018-06-01

    We examine the electron dynamics during laser-cluster interaction. In addition to the electrostatic field of an individual cluster and laser field, we consider an external transverse wiggler magnetic field, which plays a pivotal role in enhancing the electron acceleration. Single-particle simulation has been presented with a short pulse linearly polarized as well as circularly polarized laser pulses for electron acceleration in a cluster. The persisting Coulomb field allows the electron to absorb energy from the laser field. The stochastically heated electron finds a weak electric field at the edge of the cluster from where it is ejected. The wiggler magnetic field connects the regions of the stochastically heated, ejected electron from the cluster and high energy gain by the electron from the laser field outside the cluster. This increases the field strength and hence supports the electron to meet the phase of the laser field for enhanced acceleration. A long duration resonance appears with an optimized magnetic wiggler field of about 3.4 kG. Hence, the relativistic energy gain by the electron is enhanced up to a few 100 MeV with an intense short pulse laser with an intensity of about 1019 W cm‑2 in the presence of a wiggler magnetic field.

  6. Energetic Electron Acceleration and Injection During Dipolarization Events in Mercury's Magnetotail

    Science.gov (United States)

    Dewey, Ryan M.; Slavin, James A.; Raines, Jim M.; Baker, Daniel N.; Lawrence, David J.

    2017-12-01

    Energetic particle bursts associated with dipolarization events within Mercury's magnetosphere were first observed by Mariner 10. The events appear analogous to particle injections accompanying dipolarization events at Earth. The Energetic Particle Spectrometer (3 s resolution) aboard MESSENGER determined the particle bursts are composed entirely of electrons with energies ≳ 300 keV. Here we use the Gamma-Ray Spectrometer high-time-resolution (10 ms) energetic electron measurements to examine the relationship between energetic electron injections and magnetic field dipolarization in Mercury's magnetotail. Between March 2013 and April 2015, we identify 2,976 electron burst events within Mercury's magnetotail, 538 of which are closely associated with dipolarization events. These dipolarizations are detected on the basis of their rapid ( 2 s) increase in the northward component of the tail magnetic field (ΔBz 30 nT), which typically persists for 10 s. Similar to those at Earth, we find that these dipolarizations appear to be low-entropy, depleted flux tubes convecting planetward following the collapse of the inner magnetotail. We find that electrons experience brief, yet intense, betatron and Fermi acceleration during these dipolarizations, reaching energies 130 keV and contributing to nightside precipitation. Thermal protons experience only modest betatron acceleration. While only 25% of energetic electron events in Mercury's magnetotail are directly associated with dipolarization, the remaining events are consistent with the Near-Mercury Neutral Line model of magnetotail injection and eastward drift about Mercury, finding that electrons may participate in Shabansky-like closed drifts about the planet. Magnetotail dipolarization may be the dominant source of energetic electron acceleration in Mercury's magnetosphere.

  7. The electron accelerator in industry - safety aspects

    International Nuclear Information System (INIS)

    Kirthi, K.N.

    1993-01-01

    Electron beam accelerators are being used in increasing numbers in a variety of important applications. Commercial uses include radiography, food preservation, product sterilisation and radiation processing of materials. Since most of the industrial applications involve products, some that can be treated with electrons and others that require photons, electron accelerators serve this dual purpose economically. Although industrial accelerators are now regarded as standard products, finished installations show considerable diversity, reflecting the users, needs and planning. Because of the high radiation output, proper planning regarding safety is warranted. This paper discusses the hazards, safety and planning required during design and operation of the electron beam accelerators. (author). 4 refs., 1 fig

  8. Electron accelerator shielding design of KIPT neutron source facility

    Energy Technology Data Exchange (ETDEWEB)

    Zhong, Zhao Peng; Gohar, Yousry [Argonne National Laboratory, Argonne (United States)

    2016-06-15

    The Argonne National Laboratory of the United States and the Kharkov Institute of Physics and Technology of the Ukraine have been collaborating on the design, development and construction of a neutron source facility at Kharkov Institute of Physics and Technology utilizing an electron-accelerator-driven subcritical assembly. The electron beam power is 100 kW using 100-MeV electrons. The facility was designed to perform basic and applied nuclear research, produce medical isotopes, and train nuclear specialists. The biological shield of the accelerator building was designed to reduce the biological dose to less than 5.0e-03 mSv/h during operation. The main source of the biological dose for the accelerator building is the photons and neutrons generated from different interactions of leaked electrons from the electron gun and the accelerator sections with the surrounding components and materials. The Monte Carlo N-particle extended code (MCNPX) was used for the shielding calculations because of its capability to perform electron-, photon-, and neutron-coupled transport simulations. The photon dose was tallied using the MCNPX calculation, starting with the leaked electrons. However, it is difficult to accurately tally the neutron dose directly from the leaked electrons. The neutron yield per electron from the interactions with the surrounding components is very small, ∼0.01 neutron for 100-MeV electron and even smaller for lower-energy electrons. This causes difficulties for the Monte Carlo analyses and consumes tremendous computation resources for tallying the neutron dose outside the shield boundary with an acceptable accuracy. To avoid these difficulties, the SOURCE and TALLYX user subroutines of MCNPX were utilized for this study. The generated neutrons were banked, together with all related parameters, for a subsequent MCNPX calculation to obtain the neutron dose. The weight windows variance reduction technique was also utilized for both neutron and photon dose

  9. Electron acceleration by a self-diverging intense laser pulse

    International Nuclear Information System (INIS)

    Singh, K.P.; Gupta, D.N.; Tripathi, V.K.; Gupta, V.L.

    2004-01-01

    Electron acceleration by a laser pulse having a Gaussian radial and temporal profile of intensity has been studied. The interaction region is vacuum followed by a gas. The starting point of the gas region has been chosen around the point at which the peak of the pulse interacts with the electron. The tunnel ionization of the gas causes a defocusing of the laser pulse and the electron experiences the action of a ponderomotive deceleration at the trailing part of the pulse with a lower intensity rather than an acceleration at the rising part of the laser pulse with a high intensity, and thus gains net energy. The initial density of the neutral gas atoms should be high enough to properly defocus the pulse; otherwise the electron experiences some deceleration during the trailing part of the pulse and the net energy gain is reduced. The rate of tunnel ionization increases with the increase in the laser intensity and the initial density of neutral gas atoms, and with the decreases in the laser spot size, which causes more defocusing of the laser pulse. The required initial density of neutral gas atoms decreases with the increase in the laser intensity and also with the decrease in the laser spot size

  10. Repetitive nanosecond electron accelerators type URT-1 for radiation technology

    Science.gov (United States)

    Sokovnin, S. Yu.; Balezin, M. E.

    2018-03-01

    The electron accelerator URT-1М-300 for mobile installation was created for radiation disinfecting to correct drawbacks that were found the URT-1M electron accelerator operation (the accelerating voltage up to 1 МV, repetition rate up to 300 pps, electron beam size 400 × 100 mm, the pulse width about 100 ns). Accelerator configuration was changed that allowed to reduce significantly by 20% tank volume with oil where is placed the system of formation high-voltage pulses, thus the average power of the accelerator is increased by 6 times at the expense of increase in pulses repetition rate. Was created the system of the computerized monitoring parameters (output parameters and thermal mode) and remote control of the accelerator (charge voltage, pulse repetition rate), its elements and auxiliary systems (heat of the thyratron, vacuum system), the remote control panel is connected to the installation by the fiber-optical channel, what lightens the work for service personnel. For generating an electron beam up to 400 mm wide there are used metal- ceramic] and metal-dielectric cold cathodes of several emission elements (plates) with a non-uniform distribution of the electron beam current density on the output foil ± 15%. It was found that emission drop of both type of cathodes, during the operation at the high repetition rate (100 pps) is substantial at the beginning of the process, and then proceeds rather slowly that allows for continuous operation up to 40 h. Experiments showed that linear dependence of the voltage and a signal from the pin-diode remains within the range of the charge voltage 45-65 kV. Thus, voltage increases from 690 to 950 kV, and the signal from the pin-diode - from (2,8-4,6)*104 Gy/s. It allows to select electron energy quite precisely with consideration of the radiation technology requirements.

  11. High-energy cosmic-ray acceleration

    CERN Document Server

    Bustamante, M; de Paula, W; Duarte Chavez, J A; Gago, A M; Hakobyan, H; Jez, P; Monroy Montañez, J A; Ortiz Velasquez, A; Padilla Cabal, F; Pino Rozas, M; Rodriguez Patarroyo, D J; Romeo, G L; Saldaña-Salazar , U J; Velasquez, M; von Steinkirch, M

    2010-01-01

    We briefly review the basics of ultrahigh-energy cosmic-ray acceleration. The Hillas criterion is introduced as a geometrical criterion that must be fulfilled by potential acceleration sites, and energy losses are taken into account in order to obtain a more realistic scenario. The different available acceleration mechanisms are presented, with special emphasis on Fermi shock acceleration and its prediction of a power-law cosmic-ray energy spectrum. We conclude that first-order Fermi acceleration, though not entirely satisfactory, is the most promising mechanism for explaining the ultra-high-energy cosmic-ray flux.

  12. Radiological safety aspects of the operation of electron linear accelerators

    International Nuclear Information System (INIS)

    Swanson, W.P.

    1979-01-01

    This manual is intended as a guide for the planning and implementation of radiation protection programmes for all types of electron linear accelerators. Material is provided for guidance in the planning and installation stages, as well as for the implementation of radiation protection for continuing operations. Because of their rapidly growing importance, the problems of installation and radiation safety of standard medical and industrial accelerators are discussed in separate sections. Special discussions are devoted to the radiation protection problems unique to electron accelerators: thick-target bremsstrahlung, the electromagnetic cascade, the estimation of secondary-radiation yields from thick targets, and instrumental corrections for accelerator duty factor. In addition, an extensive review of neutron production is given which includes new calculations of neutron production in various materials. A recalculation of activation in a variety of materials has been done for this manual, and specific gamma-ray constants have been recalculated for a number of nuclides to take into account the contribution of K X-rays. The subjects of air and water activation, as well as toxic gas production in air have been specially reviewed. Betatrons and electron microtrons operating at the same energy produce essentially the same kind of secondary radiation as electron linacs and the material given in this manual is directly applicable to them

  13. Longitudinal transport measurements in an energy recovery accelerator with triple bend achromat arcs

    Directory of Open Access Journals (Sweden)

    F. Jackson

    2016-12-01

    Full Text Available Longitudinal properties of electron bunches (energy spread and bunch length and their manipulation are of importance in free electron lasers (FELs, where magnetic bunch length compression is a common feature of beam transport. Recirculating accelerators and energy recovery linac accelerators (ERLs have been used as FEL drivers for several decades and control of longitudinal beam transport is particularly important in their magnet lattices. We report on measurements of longitudinal transport properties in an ERL-FEL, the ALICE (Accelerators and Lasers in Combined Experiments accelerator at Daresbury Laboratory. ALICE is an energy recovery research accelerator that drives an infrared free electron laser. By measuring the time of arrival of electron bunches, the canonical longitudinal transport quantities were measured in the beam transport and bunch compression sections of the lattice. ALICE includes a four-dipole bunch compression chicane providing fixed longitudinal transport, and triple bend achromat arcs including sextupole magnets where the first and second order longitudinal transport can be adjusted. The longitudinal transport properties in these lattice sections were measured and compared with the theoretical model of the lattice. A reasonable level of agreement has been found. The effect of sextupoles in second order, as well as first order, longitudinal correction is considered, with the measurements indicating the level of alignment of the beam to the center of the sextupole.

  14. Longitudinal wake field for an electron beam accelerated through a ultra-high field gradient

    Energy Technology Data Exchange (ETDEWEB)

    Geloni, G.; Saldin, E.; Schneidmiller, E.; Yurkov, M.

    2006-12-15

    Electron accelerators with higher and higher longitudinal field gradients are desirable, as they allow for the production of high energy beams by means of compact and cheap setups. The new laser-plasma acceleration technique appears to constitute the more promising breakthrough in this direction, delivering unprecedent field gradients up to TV/m. In this article we give a quantitative description of the impact of longitudinal wake fields on the electron beam. Our paper is based on the solution of Maxwell's equations for the longitudinal field. Our conclusions are valid when the acceleration distance is much smaller than the the overtaking length, that is the length that electrons travel as a light signal from the tail of the bunch overtakes the head of the bunch. This condition is well verified for laser-plasma devices. We calculate a closed expression for the impedance and the wake function that may be evaluated numerically. It is shown that the rate of energy loss in the bunch due to radiative interaction is equal to the energy emitted through coherent radiation in the far-zone. Furthermore, an expression is found for the asymptotic limit of a large distance of the electron beam from the accelerator compared with the overtaking length. Such expression allows us to calculate analytical solutions for a Gaussian transverse and longitudinal bunch shape. Finally, we study the feasibility of Table-Top Free-Electron Lasers in the Vacuum Ultra-Violet (TT-VUV FEL) and X-ray range (TT-XFEL), respectively based on 100 MeV and 1 GeV laser-plasma accelerator drivers. Numerical estimations presented in this paper indicate that the effects of the time-dependent energy change induced by the longitudinal wake pose a serious threat to the operation of these devices. (orig.)

  15. Spin dynamics of electron beams in circular accelerators; Spindynamik von Elektronenstrahlen in Kreisbeschleunigern

    Energy Technology Data Exchange (ETDEWEB)

    Boldt, Oliver

    2014-04-15

    Experiments using high energy beams of spin polarized, charged particles still prove to be very helpful in disclosing a deeper understanding of the fundamental structure of matter. An important aspect is to control the beam properties, such as brilliance, intensity, energy, and degree of spin polarization. In this context, the present studies show various numerical calculations of the spin dynamics of high energy electron beams in circular accelerators. Special attention has to be paid to the emission of synchrotron radiation, that occurs when deflecting charged particles on circular orbits. In the presence of the fluctuation of the kinetic energy due to the photon emission, each electron spin moves non-deterministically. This stochastic effect commonly slows down the speed of all numeric estimations. However, the shown simulations cover - using appropriate approximations - trackings for the motion of thousands of electron spins for up to thousands of turns. Those calculations are validated and complemented by empirical investigations at the electron stretcher facility ELSA of the University of Bonn. They can largely be extended to other boundary conditions and thus, can be consulted for new accelerator layouts.

  16. THz cavities and injectors for compact electron acceleration using laser-driven THz sources

    Directory of Open Access Journals (Sweden)

    Moein Fakhari

    2017-04-01

    Full Text Available We present a design methodology for developing ultrasmall electron injectors and accelerators based on cascaded cavities excited by short multicycle THz pulses obtained from laser-driven THz generation schemes. Based on the developed concept for optimal coupling of the THz pulse, a THz electron injector and two accelerating stages are designed. The designed electron gun consists of a four cell cavity operating at 300 GHz and a door-knob waveguide to coaxial coupler. Moreover, special designs are proposed to mitigate the problem of thermal heat flow and induced mechanical stress to achieve a stable device. We demonstrated a gun based on cascaded cavities that is powered by only 1.1 mJ of THz energy in 300 cycles to accelerate electron bunches up to 250 keV. An additional two linac sections can be added with five and four cell cavities both operating at 300 GHz boosting the bunch energy up to 1.2 MeV using a 4-mJ THz pulse.

  17. Electron acceleration via high contrast laser interacting with submicron clusters

    International Nuclear Information System (INIS)

    Zhang Lu; Chen Liming; Wang Weiming; Yan Wenchao; Yuan Dawei; Mao Jingyi; Wang Zhaohua; Liu Cheng; Shen Zhongwei; Li Yutong; Dong Quanli; Lu Xin; Ma Jinglong; Wei Zhiyi; Faenov, Anatoly; Pikuz, Tatiana; Li Dazhang; Sheng Zhengming; Zhang Jie

    2012-01-01

    We experimentally investigated electron acceleration from submicron size argon clusters-gas target irradiated by a 100 fs, 10 TW laser pulses having a high-contrast. Electron beams are observed in the longitudinal and transverse directions to the laser propagation. The measured energy of the longitudinal electron reaches 600 MeV and the charge of the electron beam in the transverse direction is more than 3 nC. A two-dimensional particle-in-cell simulation of the interaction has been performed and it shows an enhancement of electron charge by using the cluster-gas target.

  18. Developments of electron accelerators for national economy in the AN SSSR SO IYaF

    International Nuclear Information System (INIS)

    Auslender, V.L.; Salimov, R.A.

    1979-01-01

    Described is the work aimed at developing ELV-type electrostatic electron accelerators with electron energies ranging from 0.4 to 1.5 MeV and an average beam current of up to 100 mA, and the ILU-6 electron linear accelerator with the energy from 0.5 to 2 MeV and an average beam current of up to 40 mA. To provide an output of a linearly scanned beam a special titanium window with dimension of 75 x 980 mm which provides transit of a current of up to 80 mA has been developed. To irradiate articles having a cylindrical shape two types of devices with a circular beam scanning have been developed. A device has been worked out for the output of concentrated beams into the atmosphere, in which the electron beam leaves the vacuum through a system of four ports having different diameters. Principles of operation and results of tests of these devices are briefly outlined. Examples of their application are given. More than ten tons of tubes have been irradiated on the ILU-6 accelerator to obtain thermal shrinkage, and this accelerator also served as the basis for developing a radiation sewage treatment plant. An annual economical effect is estimated at 2 million roubles per an accelerator

  19. Dose properties of x-ray beams produced by laser-wakefield-accelerated electrons

    International Nuclear Information System (INIS)

    Kainz, K K; Hogstrom, K R; Antolak, J A; Almond, P R; Bloch, C D

    2005-01-01

    Given that laser wakefield acceleration (LWFA) has been demonstrated experimentally to accelerate electron beams to energies beyond 25 MeV, it is reasonable to assess the ability of existing LWFA technology to compete with conventional radiofrequency linear accelerators in producing electron and x-ray beams for external-beam radiotherapy. We present calculations of the dose distributions (off-axis dose profiles and central-axis depth dose) and dose rates of x-ray beams that can be produced from electron beams that are generated using state-of-the-art LWFA. Subsets of an LWFA electron energy distribution were propagated through the treatment head elements (presuming an existing design for an x-ray production target and flattening filter) implemented within the EGSnrc Monte Carlo code. Three x-ray energy configurations (6 MV, 10 MV and 18 MV) were studied, and the energy width ΔE of the electron-beam subsets varied from 0.5 MeV to 12.5 MeV. As ΔE increased from 0.5 MeV to 4.5 MeV, we found that the off-axis and central-axis dose profiles for x-rays were minimally affected (to within about 3%), a result slightly different from prior calculations of electron beams broadened by scattering foils. For ΔE of the order of 12 MeV, the effect on the off-axis profile was of the order of 10%, but the central-axis depth dose was affected by less than 2% for depths in excess of about 5 cm beyond d max . Although increasing ΔE beyond 6.5 MeV increased the dose rate at d max by more than 10 times, the absolute dose rates were about 3 orders of magnitude below those observed for LWFA-based electron beams at comparable energies. For a practical LWFA-based x-ray device, the beam current must be increased by about 4-5 orders of magnitude. (note)

  20. High voltage high brightness electron accelerators with MITL voltage adder coupled to foilless diodes

    International Nuclear Information System (INIS)

    Mazarakis, M.G.; Poukey, J.W.; Frost, C.A.; Shope, S.L.; Halbleib, J.A.; Turman, B.N.

    1993-01-01

    During the last ten years the authors have extensively studied the physics and operation of magnetically-immersed electron foilless diodes. Most of these sources were utilized as injectors to high current, high energy linear induction accelerators such as those of the RADLAC family. Recently they have experimentally and theoretically demonstrated that foilless diodes can be successfully coupled to self-magnetically insulated transmission line voltage adders to produce very small high brightness, high definition (no halo) electron beams. The RADLAC/SMILE experience opened the path to a new approach in high brightness, high energy induction accelerators. There is no beam drifting through the device. The voltage addition occurs in a center conductor, and the beam is created at the high voltage end in an applied magnetic field diode. This work was motivated by the remarkable success of the HERMES-III accelerator and the need to produce small radius, high energy, high current electron beams for air propagation studies and flash x-ray radiography. In this paper they present experimental results compared with analytical and numerical simulations in addition to design examples of devices that can produce multikiloamp electron beams of as high as 100 MV energies and radii as small as 1 mm

  1. Parametrisation of linear accelerator electron beam for computerised dosimetry calculations

    International Nuclear Information System (INIS)

    Millan, P.E.; Millan, S.; Hernandez, A.; Andreo, P.

    1979-01-01

    A previously published age-diffusion model has been adapted to obtain parameters for the Saggittaire linear accelerator electron beams. The calculations are shown and the results discussed. A comparison is presented between measured and predicted percentage depth doses for electron beams at various energies between 10 and 32 MeV. Theoretical isodose curves are compared, for an energy of 10 MeV, with experimental curves. The parameters obtained are used for computer electron isodose curve calculation in a program called FIJOE adapted from a previously published program. This program makes it possible to correct for irregular body contours, but not for internal inhomogeneities. (UK)

  2. Relativistic electron beam acceleration by cascading nonlinear Landau damping of electromagnetic waves in a plasma

    International Nuclear Information System (INIS)

    Sugaya, R.; Ue, A.; Maehara, T.; Sugawa, M.

    1996-01-01

    Acceleration and heating of a relativistic electron beam by cascading nonlinear Landau damping involving three or four intense electromagnetic waves in a plasma are studied theoretically based on kinetic wave equations and transport equations derived from relativistic Vlasov endash Maxwell equations. Three or four electromagnetic waves excite successively two or three nonresonant beat-wave-driven relativistic electron plasma waves with a phase velocity near the speed of light [v p =c(1-γ -2 p ) 1/2 , γ p =ω/ω pe ]. Three beat waves interact nonlinearly with the electron beam and accelerate it to a highly relativistic energy γ p m e c 2 more effectively than by the usual nonlinear Landau damping of two electromagnetic waves. It is proved that the electron beam can be accelerated to more highly relativistic energy in the plasma whose electron density decreases temporally with an appropriate rate because of the temporal increase of γ p . copyright 1996 American Institute of Physics

  3. Research on heightening quality of free electron laser using superconducting linear accelerator

    International Nuclear Information System (INIS)

    Minehara, Eisuke

    1996-01-01

    In this paper, the superconducting high frequency linear accelerator technology using low temperature superconductor is introduced, and its application to the heightening of quality of free electron laser is discussed. The high frequency application of superconductivity is a relatively new technology, and the first superconducting high frequency linear accelerator was made at the middle of 1960s. The invention of free electron laser and the development so far are described. In free electron laser, the variation of wavelength, high efficiency and high power output are possible as compared with conventional type lasers. The price and the size are two demerits of free electron laser that remain to the last. In Japan Atomic Energy Research Institute, the adjustment experiment is carried out for the prototype free electron laser. About this prototype, injection system, superconducting accelerator, helium refrigerator, whole solid element high frequency power source, control system, electron beam transport system, undulator system and optical resonator are described. The application of high mean power output free electron laser and its future are discussed. (K.I.)

  4. Electromagnetic computer simulations of collective ion acceleration by a relativistic electron beam

    International Nuclear Information System (INIS)

    Galvez, M.; Gisler, G.R.

    1988-01-01

    A 2.5 electromagnetic particle-in-cell computer code is used to study the collective ion acceleration when a relativistic electron beam is injected into a drift tube partially filled with cold neutral plasma. The simulations of this system reveals that the ions are subject to electrostatic acceleration by an electrostatic potential that forms behind the head of the beam. This electrostatic potential develops soon after the beam is injected into the drift tube, drifts with the beam, and eventually settles to a fixed position. At later times, this electrostatic potential becomes a virtual cathode. When the permanent position of the electrostatic potential is at the edge of the plasma or further up, then ions are accelerated forward and a unidirectional ion flow is obtained otherwise a bidirectional ion flow occurs. The ions that achieve higher energy are those which drift with the negative potential. When the plasma density is varied, the simulations show that optimum acceleration occurs when the density ratio between the beam (n b ) and the plasma (n o ) is unity. Simulations were carried out by changing the ion mass. The results of these simulations corroborate the hypothesis that the ion acceleration mechanism is purely electrostatic, so that the ion acceleration depends inversely on the charge particle mass. The simulations also show that the ion maximum energy increased logarithmically with the electron beam energy and proportional with the beam current

  5. High-energy acceleration of an intense negative ion beam

    International Nuclear Information System (INIS)

    Takeiri, Y.; Ando, A.; Kaneko, O.

    1995-02-01

    A high-current H - ion beam has been accelerated with the two-stage acceleration. A large negative hydrogen ion source with an external magnetic filter produces more than 10 A of the H - ions from the grid area of 25cm x 50cm with the arc efficiency of 0.1 A/kW by seeding a small amount of cesium. The H - ion current increases according to the 3/2-power of the total beam energy. A 13.6 A of H - ion beam has been accelerated to 125 keV at the operational gas pressure of 3.4 mTorr. The optimum beam acceleration is achieved with nearly the same electric fields in the first and the second acceleration gaps on condition that the ratio of the first acceleration to the extraction electric fields is adjusted for an aspect ratio of the extraction gap. The ratio of the acceleration drain current to the H - ion current is more than 1.7. That is mainly due to the secondary electron generated by the incident H - ions on the extraction grid and the electron suppression grid. The neutralization efficiency was measured and agrees with the theoretical calculation result. (author)

  6. First observations of acceleration of injected electrons in a laser plasma beatwave experiment

    International Nuclear Information System (INIS)

    Ebrahim, N.A.; Martin, F.; Bordeur, P.; Heighway, E.A.; Matte, J.P.; Pepin, H.; Lavigne, P.

    1986-01-01

    The first experimental observations of acceleration of injected electrons in a laser driven plasma beatwave are presented. The plasma waves were excited in an ionized gas jet, using a short pulse high intensity CO 2 laser with two collinearly propagating beams (at λ = 9.6 μm and 10.6 μm) to excite a fast wave (v/sub p/ = c). The source of electrons was a laser plasma produced on an aluminum slab target by a third, synchronized CO 2 laser beam. A double-focusing dipole magnet was used to energy select and inject electrons into the beatwave, and a second magnetic spectrograph was used to analyze the accelerated electrons. Electron acceleration was only observed when the appropriate resonant plasma density was produced (∼ 10 17 cm -3 ), the two laser lines were incident on the plasma, and electrons were injected into this plasma from an external source

  7. Secondary electron emission yield in the limit of low electron energy

    CERN Document Server

    Andronov, A.N.; Kaganovich, I.D.; Startsev, E.A.; Raitses, Y.; Demidov, V.I.

    2013-04-22

    Secondary electron emission (SEE) from solids plays an important role in many areas of science and technology.1 In recent years, there has been renewed interest in the experimental and theoretical studies of SEE. A recent study proposed that the reflectivity of very low energy electrons from solid surface approaches unity in the limit of zero electron energy2,3,4, If this was indeed the case, this effect would have profound implications on the formation of electron clouds in particle accelerators,2-4 plasma measurements with electrostatic Langmuir probes, and operation of Hall plasma thrusters for spacecraft propulsion5,6. It appears that, the proposed high electron reflectivity at low electron energies contradicts to numerous previous experimental studies of the secondary electron emission7. The goal of this note is to discuss possible causes of these contradictions.

  8. Control-grid electron gun as a source of modulated electron beam for a collective accelerator

    International Nuclear Information System (INIS)

    Bakumenko, A.A.; Belikov, V.V.; Zvyagintsev, A.V.; Lyul'chenko, V.I.; Lymar', A.G.; Martynenko, P.A.; Suryadnyj, A.V.

    1989-01-01

    Structure is described and experimental results of investigations into an electron gun with transverse beam compression and control grid are presented. The pulse trailing edge is formed by a sectioned discharger. A modulated electron beam with the following parameters: 110 keV beam energy, 70 A current amplitude, 3-8 MHz modulation frequency, 100% modulation depth, ≅8-6 mm minimal beam diameter, ≅ 10μs pulse duration, 3% pulse top non-uniformity, more than 200 compression degree is obtained when introducing the positive feedback in auto-generator regime to the gun supply circuit. Further it is supposed to use the developed electron gun for heavy ion acceleration by a field of space charge of a modulated electron beam in a corrugated liner. It should be underlined that power supply of such an accelerator does not require powerful outside HF generator. 5 refs.; 1 fig

  9. Recent developments at French atomic energy commission relating to non destructive nuclear waste assay by using electron accelerator

    International Nuclear Information System (INIS)

    Lvoussi, A.; Romeyer-Dhebey, J.; Jallu, F.; Passard, C.; Mariani, A.; Recroix, H.; Payan, E.; Denis, C.; Loridon, J.; Buisson, A.; Nurdin, G.; Allano, J.; Jaureguy, J.C.

    2000-01-01

    An important program is currently in progress at several laboratories over the world for the development of sensitive, practical non-destructive assay techniques for the quantification of low level transuranics (TRU) in solid wastes. The wide variety of materials and contaminants, the low concentrations and large volumes involve, all make this kind of assay a complicated affair. Over the last few years, considerable progress has been made in the field of assay techniques for low level contaminated wastes. This report describes the methods being developed at French Atomic Energy Commission (C.E.A.) in Cadarache to assay high density TRU waste packages by using photon, neutron or both photon and neutron as interrogating particles. All of these particles are produced by using a pulsed electron linear accelerator from which the photons are produced following Bremsstrahlung phenomena on a heavy metallic converter and the neutrons are generated in appropriate low level photoneutron threshold target (e.g. Beryllium). The dynamic of photonuclear interactions and photoneutron production, use of an electron linear accelerator as a particle source, experimental and electronics details, experimental results, simulation to experiment performances and future experimental and theoretical studies are discussed. (authors)

  10. Modernization of electron accelerator on the base of the RUP-400 x-ray unit

    International Nuclear Information System (INIS)

    Buslaev, I.I.; Kon'kov, N.G.; Kochetov, O.N.; Krylov, S.Yu.; Nikolaev, S.M.

    1976-01-01

    A device has been designed enabling one to change directly from the control panel relation of high to low energy electrons in the beam with a view to up-date a linear electron accelerator. The device comprises a high-voltage transformer accommodating an accelerating tube of the vacuum system with a titanium pump and a scanner. 1.5 BPV-2-400 X-ray tube with a renewable cathode is used as an accelerating tube. As a result of these modifications the accelerator has become smaller and not so heavy. Its characteristics on material irradiation have also improved

  11. Gun power source for electron gun of 3 MeV DC accelerator

    International Nuclear Information System (INIS)

    Dewangan, S.; Sharma, D.K.; Nanu, K.

    2011-01-01

    In DC electron beam accelerator electron gun is situated at high voltage terminal which requires constant power irrespective of beam energy. Floating power source is required for gun. This paper describes the scheme of static gun power source derived from parallel coupled voltage multiplier column. (author)

  12. Electron pulse shaping in the FELIX RF accelerator

    International Nuclear Information System (INIS)

    Weits, H.H.; Geer, C.A.J. van der; Oepts, D.; Meer, A.F.G. van der

    1999-01-01

    The FELIX free-electron laser uses short pulses of relativistic electrons produced by an RF accelerator. The design target for the duration of these electron bunches was around 3 ps. In experiments we observed that the bunches emit coherently enhanced spontaneous emission (CSE) when they travel through an undulator. It was demonstrated that the power level of the CSE critically depends on the settings of the accelerator. In this article we seek to explain these observations by studying the length and shape of the electron bunches as a function of the settings of the accelerator. A particle-tracking model was used to simulate the acceleration and transport processes. These include bunch compression in a 14-cell travelling wave buncher cavity, acceleration in a travelling wave linear accelerator, and passage through a (dispersive) chicane structure. The effect of the phase setting of the RF accelerating field with respect to the arrival time of the electron bunch in each accelerator structure was studied. The parameter range of the simulations is related to that of an actual free-electron laser experiment using these bunches. We find that, for specific settings of the accelerating system, electron pulses with a length of 350 μm FWHM (1 ps) are produced. The charge in the bunch rises steeply within a distance of 25 μm. This bunch shape explains the high level of coherently enhanced spontaneous emission observed in the FELIX laser. (author)

  13. Controller for control of pulsed electron linear accelerator

    International Nuclear Information System (INIS)

    Bryazgin, A.A.; Faktorovich, B.L.

    1995-01-01

    The controller is based on the K1816VE31 microprocessor and contains 22-channel integrating 10-digital two-wire analog-to-digital converter, 8-channel 12-digit digital-to-analog converter, 24-digit output register, 16-digit input register pulse generator in the range of 0.5 - 50 Hz with the regulation step of 0.05 Hz and delayed pulse generator. The controller is used for pulsed electron linear accelerator control and is reduced to regulation of the electron beam pulse repetition rate and beam energy. 1 ref., 1 fig

  14. Construction of an electron accelerator of 20 KeV: application in the polymeric study

    International Nuclear Information System (INIS)

    Sandonato, G.M.

    1983-01-01

    A low energy electron accelerator (maximum energy 20 KeV) is constructed. A black and white kinescope electron gun, with a single thermionic emitter was used as electron source. The energy of electron beam can be changed continuously from 0 to 20 KeV. The intensity of the current can be changed from a minimum of 10 -12 A to a maximum of 3 μA, and can be mantained contant in time after its value has been fixed. The irradiated area can be changed from a diameter of 1 milimeter to a maximum of 6 centimeter, by focalizing or defocalizing the image of electron beam. The final pressure reached in vacuum chambers was 10 -7 Torr. During operation the surface of cathode of electron gun is damaged by ion bombardeament. The degree of damage can be checked if the cathode image is focalized and examined on a luminescent screen. The accelerator was used to study electron irradiation effects in Teflon, employing the method of the split Faraday cup. Transient charging and discharging currents were measured. The average range of electrons of the electrons and the induced conductivity were determined. (Author) [pt

  15. Ionospheric electron acceleration by electromagnetic waves near regions of plasma resonances

    International Nuclear Information System (INIS)

    Villalon, E.

    1989-01-01

    Electron acceleration by electromagnetic fields propagating in the inhomogeneous ionospheric plasma is investigated. It is found that high-amplitude short wavelength electrostatic waves are generated by the incident electromagnetic fields that penetrate the radio window. These waves can very efficiently transfer their energy to the electrons if the incident frequency is near the second harmonic of the cyclotron frequency

  16. Optically controlled laser-plasma electron accelerator for compact gamma-ray sources

    Science.gov (United States)

    Kalmykov, S. Y.; Davoine, X.; Ghebregziabher, I.; Shadwick, B. A.

    2018-02-01

    Generating quasi-monochromatic, femtosecond γ-ray pulses via Thomson scattering (TS) demands exceptional electron beam (e-beam) quality, such as percent-scale energy spread and five-dimensional brightness over 1016 A m-2. We show that near-GeV e-beams with these metrics can be accelerated in a cavity of electron density, driven with an incoherent stack of Joule-scale laser pulses through a mm-size, dense plasma (n 0 ˜ 1019 cm-3). Changing the time delay, frequency difference, and energy ratio of the stack components controls the e-beam phase space on the femtosecond scale, while the modest energy of the optical driver helps afford kHz-scale repetition rate at manageable average power. Blue-shifting one stack component by a considerable fraction of the carrier frequency makes the stack immune to self-compression. This, in turn, minimizes uncontrolled variation in the cavity shape, suppressing continuous injection of ambient plasma electrons, preserving a single, ultra-bright electron bunch. In addition, weak focusing of the trailing component of the stack induces periodic injection, generating, in a single shot, a train of bunches with controllable energy spacing and femtosecond synchronization. These designer e-beams, inaccessible to conventional acceleration methods, generate, via TS, gigawatt γ-ray pulses (or multi-color pulse trains) with the mean energy in the range of interest for nuclear photonics (4-16 MeV), containing over 106 photons within a microsteradian-scale observation cone.

  17. Environmental assessment: Continuous Electron Beam Accelerator Facility, Newport News, Virginia

    International Nuclear Information System (INIS)

    1987-01-01

    This Environmental Assessment has been prepared by the US Department of Energy (DOE) to fulfill its obligations pursuant to Sect. 102 of the National Environmental Policy Act (NEPA) of 1969 (Public Law 91-190). The proposed federal action addressed in this document is DOE's funding of a Continuous Electron Beam Accelerator Facility (CEBAF) at Newport News, Virginia. DOE intends to contract with the Southeastern Universities Research Association (SURA) for operation of CEBAF, a continuous wave (CW) linear accelerator system (linac) capable of providing high-duty-factor beams throughout the energy range from 0.5 to 4.0 GeV. CEBAF will be the first of its kind worldwide and will offer a multi-GeV energy, high-intensity, high-duty-factor electron beam for use by the US nuclear physics community in research on the states of nuclear matter and the short-distance behavior of nuclei. The CEBAF project is largely in the conceptual design stage, with some components in the preliminary design stage. Construction is anticipated to begin in 1987 and be completed by 1992

  18. Application of high power modulated intense relativistic electron beams for development of Wake Field Accelerator

    International Nuclear Information System (INIS)

    Friedman, M.

    1989-01-01

    This final Progress Report addresses DOE-sponsored research on the development of future high-gradient particle accelerators. The experimental and the theoretical research, which lasted three years, investigated the Two Beam Accelerator (TBA). This high-voltage-gradient accelerator was powered by a modulated intense relativistic electron beam (MIREB) of power >10 10 watts. This research was conceived after a series of successful experiments performed at NRL generating and using MIREBs. This work showed that an RF structure could be built which was directly powered by a modulated intense relativistic electron beam. This structure was then used to accelerate a second electron beam. At the end of the three year project the proof-of-principle accelerator demonstrated the generation of a high current beam of electrons with energy >60 MeV. Scaling laws needed to design practical devices for future applications were also derived

  19. Derivation of electron and photon energy spectra from electron beam central axis depth dose curves

    Energy Technology Data Exchange (ETDEWEB)

    Deng Jun [Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA 94305 (United States)]. E-mail: jun@reyes.stanford.edu; Jiang, Steve B.; Pawlicki, Todd; Li Jinsheng; Ma, C.M. [Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA 94305 (United States)

    2001-05-01

    A method for deriving the electron and photon energy spectra from electron beam central axis percentage depth dose (PDD) curves has been investigated. The PDD curves of 6, 12 and 20 MeV electron beams obtained from the Monte Carlo full phase space simulations of the Varian linear accelerator treatment head have been used to test the method. We have employed a 'random creep' algorithm to determine the energy spectra of electrons and photons in a clinical electron beam. The fitted electron and photon energy spectra have been compared with the corresponding spectra obtained from the Monte Carlo full phase space simulations. Our fitted energy spectra are in good agreement with the Monte Carlo simulated spectra in terms of peak location, peak width, amplitude and smoothness of the spectrum. In addition, the derived depth dose curves of head-generated photons agree well in both shape and amplitude with those calculated using the full phase space data. The central axis depth dose curves and dose profiles at various depths have been compared using an automated electron beam commissioning procedure. The comparison has demonstrated that our method is capable of deriving the energy spectra for the Varian accelerator electron beams investigated. We have implemented this method in the electron beam commissioning procedure for Monte Carlo electron beam dose calculations. (author)

  20. Development of an automated system for the operation of an electron beam accelerator

    International Nuclear Information System (INIS)

    Somessari, Samir L.; Moura, João A.; Calvo, Wilson Ap. Parejo

    2017-01-01

    Electron beam accelerators are used in many applications, such as basic physical research, chemistry, medicine, molecular biology, microelectronics, agriculture and industry, among others. The majority of the accelerators have electrons from a hot tungsten filament and their energy is increased as it passes through an electric field in the vacuum chamber. For industrial purposes, the most common model is Dynamitrons®. At IPEN-CNEN/SP, there is an electron beam accelerator Dynamitron® Type (Manufactured by RDI- Radiation Dynamics Inc., 1978) model DC1500/25/4. The technology applied was available in the 60's and 70's, but, nowadays is obsolete. Moreover, there are not original spare parts for this equipment any longer. The aim of this work is to develop a nationalized automated operation system for the accelerator, to replace the old equipment. (author)

  1. Development of an automated system for the operation of an electron beam accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Somessari, Samir L.; Moura, João A.; Calvo, Wilson Ap. Parejo, E-mail: somessar@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2017-11-01

    Electron beam accelerators are used in many applications, such as basic physical research, chemistry, medicine, molecular biology, microelectronics, agriculture and industry, among others. The majority of the accelerators have electrons from a hot tungsten filament and their energy is increased as it passes through an electric field in the vacuum chamber. For industrial purposes, the most common model is Dynamitrons®. At IPEN-CNEN/SP, there is an electron beam accelerator Dynamitron® Type (Manufactured by RDI- Radiation Dynamics Inc., 1978) model DC1500/25/4. The technology applied was available in the 60's and 70's, but, nowadays is obsolete. Moreover, there are not original spare parts for this equipment any longer. The aim of this work is to develop a nationalized automated operation system for the accelerator, to replace the old equipment. (author)

  2. Electron acceleration during streamer collisions in air

    DEFF Research Database (Denmark)

    Köhn, Christoph; Chanrion, Olivier; Neubert, Torsten

    2017-01-01

    charge fields, with a Monte Carlo scheme accounting for collisions and ionization. We present the electron density, the electric field, and the velocity distribution as functions of space and time. Assuming a background electric field 1.5 times the breakdown field, we find that the electron density......High-voltage laboratory experiments show that discharges in air, generated over a gap of one meter with maximal voltage of 1 MV, may produce X-rays with photon energies up to 1 MeV. It has been suggested that the photons are bremsstrahlung from electrons accelerated by the impulsive, enhanced field...... during collisions of negative and a positive streamers. To explore this process, we have conducted the first self-consistent particle simulations of streamer encounters. Our simulation model is a 2-D, cylindrically symmetric, particle-in-cell code tracing the electron dynamics and solving the space...

  3. Matching beams on photon/electron linear accelerators

    International Nuclear Information System (INIS)

    Oliver, L.; Vial, P.; Hunt, P.

    2004-01-01

    Full text: There are a number of obvious reasons to match megavoltage X-ray and electron beams for clinical purposes. If two dual-purpose X-ray/electron linear accelerators are of the same design and manufacturer, then this might be possible. The issue is however whether the beams can be matched sufficiently close to be considered the same for patient treatments and planning data for dose calculation purposes. If successfully achieved, there are significant advantages in reduced commissioning time, less work in planning and flexibility in the treatment of patients between the two treatment machines. We have investigated matching a new Varian Clinac 21EX with our 1993 Varian Clinac 2100 C/D. A Varian Clinac 1800 was the first linear accelerator installed at RNSH in 1987. When the Clinac 2100 C/D was installed in 1993, we attempted to match all the X-ray and electron beams with the original Clinac 1800 physical data. The X-ray beam characteristics were satisfactory but the electron beams were not sufficiently compatible for planning or patient treatment purposes. A different designed scattering foil and electron applicator were the cause of the different electron beam physical characteristics between the two models. In replacing the Clinac 1800 with the Clinac 21EX, we have used the original 1993 data of the Clinac 2100 C/D as the gold standard to aim for. Initial measurements during acceptance tests showed that all beams satisfied the manufacturer's specification. The energy was then matched to the existing clinical physics data by adjusting the bending magnet power supply and re-tuning the accelerator. This involved matching % depth dose and the corresponding ratio of 10 and 20 cm % depth dose ratio for 6MV and 18 MV X-ray beams. For 6, 9, 12, 16 and 20 MeV electron beams the normal physical parameters of depth of maximum (R max ), the practical range (R p ), the depth of 50% (R 50 ), the slope (G), the average energy at the surface (E 0 ) and the % photon

  4. High-energy cosmic-ray acceleration

    OpenAIRE

    Bustamante, M; Carrillo Montoya, G; de Paula, W; Duarte Chavez, J A; Gago, A M; Hakobyan, H; Jez, P; Monroy Montañez, J A; Ortiz Velasquez, A; Padilla Cabal, F; Pino Rozas, M; Rodriguez Patarroyo, D J; Romeo, G L; Saldaña-Salazar , U J; Velasquez, M

    2010-01-01

    We briefly review the basics of ultrahigh-energy cosmic-ray acceleration. The Hillas criterion is introduced as a geometrical criterion that must be fulfilled by potential acceleration sites, and energy losses are taken into account in order to obtain a more realistic scenario. The different available acceleration mechanisms are presented, with special emphasis on Fermi shock acceleration and its prediction of a power-law cosmic-ray energy spectrum. We conclude that first-order Fermi accelera...

  5. An energy recovery electron linac-on-ring collider

    International Nuclear Information System (INIS)

    Merminga, L.; Krafft, G.A.; Lebedev, V.A.; Ben-Zvi, I.

    2000-01-01

    We present the design of high-luminosity electron-proton/ion colliders in which the electrons are produced by an Energy Recovering Linac (ERL). Electron-proton/ion colliders with center of mass energies between 14 GeV and 100 GeV (protons) or 63 GeV/A (ions) and luminosities at the 10 33 (per nucleon) level have been proposed recently as a means for studying hadronic structure. The linac-on-ring option presents significant advantages with respect to: (1) spin manipulations (2) reduction of the synchrotron radiation load in the detectors (3) a wide range of continuous energy variability. Rf power and beam dump considerations require that the electron linac recover the beam energy. Based on extrapolations from actual measurements and calculations, energy recovery is expected to be feasible at currents of a few hundred mA and multi-GeV energies. Luminosity projections for the linac-ring scenario based on fundamental limitations are presented. The feasibility of an energy recovery electron linac-on-proton ring collider is investigated and four conceptual point designs are shown corresponding to electron to proton energies of: 3 GeV on 15 GeV, 5 GeV on 50 GeV and 10 GeV on 250 GeV, and for gold ions with 100 GeV/A. The last two designs assume that the protons or ions are stored in the existing RHIC accelerator. Accelerator physics issues relevant to proton rings and energy recovery linacs are discussed and a list of required R and D for the realization of such a design is presented

  6. High-energy electron acceleration in the gas-puff Z-pinch plasma

    Energy Technology Data Exchange (ETDEWEB)

    Takasugi, Keiichi, E-mail: takasugi@phys.cst.nihon-u.ac.jp [Institute of Quantum Science, Nihon University, 1-8 Kanda-Surugadai, Chiyoda, Tokyo 101-8308 (Japan); Miyazaki, Takanori [Institute of Quantum Science, Nihon University, 1-8 Kanda-Surugadai, Chiyoda, Tokyo 101-8308, Japan and Dept. Innovation Systems Eng., Utsunomiya University, 7-1-2 Yoto, Utsunomiya, Tochigi 321-8585 (Japan); Nishio, Mineyuki [Anan National College of Technology, 265 Aoki, Minobayashi, Anan, Tokushima 774-0017 (Japan)

    2014-12-15

    The characteristics of hard x-ray generation were examined in the gas-puff z-pinch experiment. The experiment on reversing the voltage was conducted. In both of the positive and negative discharges, the x-ray was generated only from the anode surface, so it was considered that the electrons were accelerated by the induced electromagnetic force at the pinch time.

  7. A simultaneous electron energy and dosimeter calibration method for an electron beam irradiator

    International Nuclear Information System (INIS)

    Tanaka, R.; Sunaga, H.; Kojima, T.

    1991-01-01

    In radiation processing using electron accelerators, the reproducibility of absorbed dose in the product depends not only on the variation of beam current and conveyor speed, but also on variations of other accelerator parameters. This requires routine monitoring of the beam current and the scan width, and also requires periodical calibration of routine dosimeters usually in the shape of film, electron energy, and other radiation field parameters. The electron energy calibration is important especially for food processing. The dose calibration method using partial absorption calorimeters provides only information about absorbed dose. Measurement of average electron current density provides basic information about the radiation field formed by the beam scanning and scattering at the beam window, though it does not allow direct dose calibration. The total absorption calorimeter with a thick absorber allows dose and dosimeter calibration, if the depth profile of relative dose in a reference absorber is given experimentally. It also allows accurate calibration of the average electron energy at the surface of the calorimeter core, if electron fluence received by the calorimeter is measured at the same time. This means that both electron energy and dosimeters can be simultaneously calibrated by irradiation of a combined system including the calorimeter, the detector of the electron current density meter, and a thick reference absorber for depth profile measurement of relative dose. We have developed a simple and multifunctional system using the combined calibration method for 5 MeV electron beams. The paper describes a simultaneous calibration method for electron energy and film dosimeters, and describes the electron current density meter, the total absorption calorimeter, and the characteristics of this method. (author). 13 refs, 7 figs, 3 tabs

  8. Landscape of Future Accelerators at the Energy and Intensity Frontier

    Energy Technology Data Exchange (ETDEWEB)

    Syphers, M. J. [Northern Illinois U.; Chattopadhyay, S. [Northern Illinois U.

    2016-11-21

    An overview is provided of the currently envisaged landscape of charged particle accelerators at the energy and intensity frontiers to explore particle physics beyond the standard model via 1-100 TeV-scale lepton and hadron colliders and multi-Megawatt proton accelerators for short- and long- baseline neutrino experiments. The particle beam physics, associated technological challenges and progress to date for these accelerator facilities (LHC, HL-LHC, future 100 TeV p-p colliders, Tev-scale linear and circular electron-positron colliders, high intensity proton accelerator complex PIP-II for DUNE and future upgrade to PIP-III) are outlined. Potential and prospects for advanced “nonlinear dynamic techniques” at the multi-MW level intensity frontier and advanced “plasma- wakefield-based techniques” at the TeV-scale energy frontier and are also described.

  9. The electronic logbook for LNL accelerators

    International Nuclear Information System (INIS)

    Canella, S.; Carletto, O.

    2012-01-01

    In spring 2009 all run-time data concerning the particle accelerators at LNL (Legnaro National Laboratory) were still registered mainly on paper. The electrostatic accelerator TANDEM-XTU and its Negative Source data were logged on a large format paper logbook. For the ALPI booster and the PIAVE injector with its Positive ECR Source a number of independent paper notebooks were used, together with plain data files containing raw instant snapshots of the RF super-conductive accelerators. At that time a decision was taken to build a new tool for a general electronic registration of accelerators run-time data. The result of this effort, the LNL electronic logbook, is here presented. The LNL electronic logbook is a many-layers software tool that is made of data sets and software programs. It is used to register states, events, texts, images and files according to the shift structures in the working time of the LNL accelerators. The same system is used to register data and to retrieve them. It may be accessed by standard browser on any platform

  10. Modified two beam accelerator driven by a D.C. pelletron free electron laser

    International Nuclear Information System (INIS)

    Larson, D.

    1985-01-01

    Assembling the next generation of linear particle accelerators requires progress in three areas. (1) Sources must be developed to provide the coherent electromagnetic radiation used to power the device. (2) Physical structures must be designed which efficiently transfer the power to the high energy beam. (3) Cooling techniques must be developed in order to enhance beam transport and to provide sufficient luminosity. This paper will describe a method of obtaining a highly efficient coherent radiation source by using a continuous wave Free Electron Laser (FEL). Several possibilities exist for an accelerating structure which could use this radiation as a power source. These include scaling down the size of traditional RF cavities, inverse free electron lasers, and surface grating schemes. Inverse free electron lasers have the possibility of intrinsic cooling of the high energy beam

  11. Industrial applications of electron beam accelerators

    International Nuclear Information System (INIS)

    Braid, W.G. Jr.

    1976-01-01

    The use of electron beam accelerators for crosslinking polyolefins for shrinking food packaging is discussed. Irradiation procedures, accelerator characteristics, and industrial operations are described

  12. Electron Acceleration in the Field-reversed Configuration (FRC) by Slowly Rotation Odd-parity Magnetic Fields (RMFo)

    International Nuclear Information System (INIS)

    Glasser, A.H.; Cohen, S.A.

    2001-01-01

    The trajectories of individual electrons are studied numerically in a 3D, prolate, FRC [field-reversed configuration] equilibrium magnetic geometry with added small-amplitude, slowly rotating, odd-parity magnetic fields (RMFos). RMFos cause electron heating by toroidal acceleration near the O-point line and by field-parallel acceleration away from it, both followed by scattering from magnetic-field inhomogeneities. Electrons accelerated along the O-point line move antiparallel to the FRC's current and attain average toroidal angular speeds near that of the RMFo, independent of the sense of RMFo rotation. A conserved transformed Hamiltonian, dependent on electron energy and RMFo sense, controls electron flux-surface coordinate

  13. Current and future industrial application of electron accelerators in Thailand

    International Nuclear Information System (INIS)

    Siri-Upathum, Chyagrit

    2003-01-01

    Industrial applications of electron accelerators in Thailand, first introduced in 1997 for radiation sterilized products such as doctor gown, pampas, feminine napkin etc followed by installation of accelerators, one with energies at 20 MV and the other at 5 MV to produce new value added products like gem stones, topaz, tourmaline and zircon. The machines operate in pulse mode and is also used for irradiation services for food and sterilized products treatment. The need for low and medium energy accelerators in radiation technology is stressed. They are to be used for crosslinking of electrical wire and cable, heat shrinkable materials, low protein concentrated rubber latex, rubber wood furniture and parts, and silk protein degradation. The role of governmental organizations like Nuclear Research Institute (OAEP) and universities in stimulating the utilization of radiation processing in Thailand is strengthened. (S. Ohno)

  14. Current and future industrial application of electron accelerators in Thailand

    Energy Technology Data Exchange (ETDEWEB)

    Siri-Upathum, Chyagrit [Chulalongkorn Univ., Faculty of Engineering, Bangkok (Thailand)

    2003-02-01

    Industrial applications of electron accelerators in Thailand, first introduced in 1997 for radiation sterilized products such as doctor gown, pampas, feminine napkin etc followed by installation of accelerators, one with energies at 20 MV and the other at 5 MV to produce new value added products like gem stones, topaz, tourmaline and zircon. The machines operate in pulse mode and is also used for irradiation services for food and sterilized products treatment. The need for low and medium energy accelerators in radiation technology is stressed. They are to be used for crosslinking of electrical wire and cable, heat shrinkable materials, low protein concentrated rubber latex, rubber wood furniture and parts, and silk protein degradation. The role of governmental organizations like Nuclear Research Institute (OAEP) and universities in stimulating the utilization of radiation processing in Thailand is strengthened. (S. Ohno)

  15. BOOK REVIEW: Electron acceleration in the aurora and beyond

    Science.gov (United States)

    McClements, K. G.

    1999-08-01

    Duncan Bryant is a retired space plasma physicist who spent most of his career at the Rutherford-Appleton Laboratory in Oxfordshire, England. For many years he has been challenging a widely accepted theory, that auroral electrons are accelerated by double layers, on the grounds that it contains a fundamental error (allegedly, an implicit assumption that charged particles can gain energy from conservative fields). It is, of course, right that models of particle acceleration in natural plasmas should be scrutinized carefully in terms of their consistency with basic physical principles, and I believe that Dr Bryant has performed a valuable service by highlighting this issue. He maintains that auroral electron acceleration by double layers is fundamentally untenable, and that acceleration takes place instead via resonant interactions with lower hybrid waves. In successive chapters, he asserts that essentially the same process can account for electron acceleration observed at the Earth's bow shock, in the neighbourhood of an `artificial comet' produced as part of the Active Magnetospheric Particle Explorers (AMPTE) space mission in 1984/85, in the solar wind, at the Earth's magnetopause, and in the Earth's magneto- sphere. The evidence for this is not always convincing: waves with frequencies of the order of the lower hybrid resonance are often observed in these plasma environments, but in general it is difficult to identify clearly which wave mode is being observed (whistlers, for example, have frequencies in approximately the same range as lower hybrid waves). Moreover, it is not at all clear that the waves which are observed, even if they were of the appropriate type, would have sufficient intensity to accelerate electrons to the extent observed. The author makes a persuasive case, however, that acceleration in the aurora, and in other plasma environments accessible to in situ measurements, involves some form of wave turbulence. In Chapter 2 it is pointed out that

  16. Prototype of industrial electrons accelerator

    International Nuclear Information System (INIS)

    Lopez, V.H.; Valdovinos, A.M.

    1992-01-01

    The interest and the necessity of Mexico's industry in the use of irradiation process has been increased in the last years. As examples are the irradiation of combustion gases (elimination of NO x and SO 2 ) and the polymer cross-linking between others. At present time at least twelve enterprises require immediately of them which have been contacted by electron accelerators suppliers of foreign countries. The first project step consisted in to identify the electrons accelerator type that in can be constructed in Mexico with the major number of possible equipment, instruments, components and acquisition materials local and useful for the major number of users. the characteristics of the accelerator prototype are: accelerator type transformer with multiple secondary insulated and rectifier circuits with a potential of 0.8 MV of voltage, the second step it consisted in an economic study that permitted to demonstrate the economic feasibility of its construction. (Author)

  17. A practical guide to modern high energy particle accelerators

    International Nuclear Information System (INIS)

    Holmes, S.D.

    1987-10-01

    The purpose of these lectures is to convey an understanding of how particle accelerators work and why they look the way they do. The approach taken is physically intuitive rather than mathematically rigorous. The emphasis is on the description of proton circular accelerators and colliders. Linear accelerators are mentioned only in passing as sources of protons for higher energy rings. Electron accelerators/storage rings and antiproton sources are discussed only by way of brief descriptions of the features which distinguish them from proton accelerators. The basics of how generic accelerators work are discussed, focusing on descriptions of what sets the overall scale, single particle dynamics and stability, and descriptions of the phase space of the particle beam, the information thus presented is then used to go through the exercise of designing a Superconducting Super Collider

  18. Monte Carlo computation of Bremsstrahlung intensity and energy spectrum from a 15 MV linear electron accelerator tungsten target to optimise LINAC head shielding

    International Nuclear Information System (INIS)

    Biju, K.; Sharma, Amiya; Yadav, R.K.; Kannan, R.; Bhatt, B.C.

    2003-01-01

    The knowledge of exact photon intensity and energy distributions from the target of an electron target is necessary while designing the shielding for the accelerator head from radiation safety point of view. The computations were carried out for the intensity and energy distribution of photon spectrum from a 0.4 cm thick tungsten target in different angular directions for 15 MeV electrons using a validated Monte Carlo code MCNP4A. Similar results were computed for 30 MeV electrons and found agreeing with the data available in literature. These graphs and the TVT values in lead help to suggest an optimum shielding thickness for 15 MV Linac head. (author)

  19. Electron accelerator for tunneling through hard rock

    International Nuclear Information System (INIS)

    Avery, R.T.; Keefe, D.

    1975-10-01

    Earlier work demonstrated that intense sub-microsecond bursts of energetic electrons cause significant pulverization and spalling of a variety of rock types. The spall debris generally consists of sand, dust, and small flakes. If carried out at rapid repetition rate, this can lead to a promising technique for increasing the speed and reducing the cost of underground excavation of tunnels, mines, and storage spaces. The conceptual design features of a Pulsed Electron Tunnel Excavator capable of tunneling approximately ten times faster than conventional drill/blast methods are presented, with primary emphasis on the electron accelerator and only a brief description of the tunneling aspects. Of several candidate types of accelerators, a linear induction accelerator producing electron pulses (5 MV, 5 kA, 1.0 μs = 25 kJ) at a 360 Hz rate was selected for the conceptual example. This provides the required average electron beam power output of 9 MW. The feasibility of such an accelerator is discussed

  20. Electron accelerator for tunneling through hard rock

    International Nuclear Information System (INIS)

    Avery, R.T.; Keefe, D.

    1975-01-01

    Earlier work demonstrated that intense sub-microsecond bursts of energetic electrons cause significant pulverization and spalling of a variety of rock types. The spall debris generally consists of sand, dust, and small flakes. If carried out at rapid repetition rate, this can lead to a promising technique for increasing the speed and reducing the cost of underground excavation of tunnels, mines, and storage spaces. The conceptual design features of a Pulsed Electron Tunnel Excavator capable of tunneling approximately ten times faster than conventional drill/blast methods are presented with primary emphasis on the electron accelerator and only a brief description of the tunneling aspects. Of several candidate types of accelerators, a linear induction accelerator producing electron pulses (5 MV, 5 kA, 1.0 μs = 25 kJ) at a 360 Hz rate was selected for the conceptual example. This provides the required average electron beam power output of 9 MW. The feasibility of such an accelerator is discussed

  1. Dosimetry measurements during the commissioning of the GJ-2 electron accelerator

    DEFF Research Database (Denmark)

    Chosdu, R.; Hilmy, N.; Tobing, R.

    1995-01-01

    The GJ-2 electron accelerator (made in China, Sanghai) was put into operation at the Centre for Application of Isotopes and Radiation in Jakarta, Indonesia. In the course of the commissioning of the machine its main technical parameters were measured under different operating conditions. The elec......The GJ-2 electron accelerator (made in China, Sanghai) was put into operation at the Centre for Application of Isotopes and Radiation in Jakarta, Indonesia. In the course of the commissioning of the machine its main technical parameters were measured under different operating conditions......, ethanol-chlorobenzene dosimeter solution and FWT-60 film dosimeters. The applicability of polystyrene calorimeters designed for low electron energies at Ris phi National Laboratory was also tested for nominal dose determination....

  2. Analytical use of electron accelerators

    International Nuclear Information System (INIS)

    Kapitsa, S.P.; Chapyzhnikov, B.A.; Firsov, V.I.; Samosyuk, V.N.; Tsipenyuk, Y.M.

    1985-01-01

    After detailed investigation the authors conclude that the newest electron accelerators provide good scope for gamma activation and also for producing neutrons for neutron activation. These accelerators are simpler and safer than reactors, and one can provide fairly homogeneous irradiation of substantial volumes, and the determination speed and sensitivity then constitute the main advantages. The limits of detection and the reproducibility are sufficient to handle a wide range of tasks. Analysts at present face a wide range of unlikely extreme problems, while the selectivity provides exceptional analysis facilities. However, the record examples are not to be taken as exceptions, since activation analysis based on electron accelerators opens up essentially universal scope for analyzing all elements at the concentrations and accuracies currently involved, which will involve its extensive use in analytical practice in the foreseeable future. The authors indicate that the recognition of these possibilities governs the general use of these methods and the employment of current efficient fast-electron sources to implement them

  3. Auroral electron acceleration by lower-hybrid waves

    International Nuclear Information System (INIS)

    Bingham, R.; Bryant, D.A.; Hall, D.S.

    1986-01-01

    Because the particles and electric fields association with inverted-V electron streams do not have the characteristics expected for acceleration by a quasistatic potential difference, the possiblity that the electrons are stochastically accelerated by waves is investigated. It is demonstrated that the lower hybrid waves seen on auroral field lines have the righ properties to account for the electron acceleration. It is further shown that the lower hybrid wave power measured on auroral field lines can be generated by the streaming ions observed at the boundary of the plasma sheet, and that this wave power is sufficient to account for the electron power observed close to the atmosphere. (author)

  4. Acceleration of polarized proton in high energy accelerators

    International Nuclear Information System (INIS)

    Lee, S.Y.

    1991-01-01

    In low to medium energy accelerators, betatron tune jumps and vertical orbit harmonic correction methods have been used to overcome the intrinsic and imperfection resonances. At high energy accelerators, snakes are needed to preserve polarization. The author analyzes the effects of snake resonances, snake imperfections, and overlapping resonances on spin depolarization. He discusses also results of recent snake experiments at the IUCF Cooler Ring. The snake can overcome various kinds of spin depolarization resonances. These experiments pointed out further that partial snake can be used to cure the imperfection resonances in low to medium energy accelerators

  5. First experimental results of the BNL inverse free electron laser accelerator

    International Nuclear Information System (INIS)

    Steenbergen, A. van; Gallardo, J.; Babzien, M.; Skaritka, J.; Wang, X.J.; Sandweiss, J.; Fang, J.M.; Qiu, X.

    1996-10-01

    A 40 MeV electron beam, using the inverse3e free-electron laser interaction, has been accelerated by ΔE/E = 2.5% over a distance of 0.47 m. The electrons interact with a 1--2 GW CO 2 laser beam bounded by a 2.8 mm ID sapphire circular waveguide in the presence of a tapered wiggler with Bmax ∼ 1 T and a period 2.89 cm ≤ λ w ≤ 3.14 cm. The experimental results of ΔE/E as a function of electron energy E, peak magnetic field Bw and laser power W 1 compare well with analytical and 1-D numerical simulations and permit scaling to higher laser power and electron energy

  6. Study of absorbed dose distribution to high energy electron beams

    International Nuclear Information System (INIS)

    Cecatti, E.R.

    1983-01-01

    The depth absorbed dose distribution by electron beams was studied. The influence of the beam energy, the energy spread, field size and design characteristics of the accelerator was relieved. Three accelerators with different scattering and collimation systems were studied leading todifferent depth dose distributions. A theoretical model was constructed in order to explain the increase in the depth dose in the build-up region with the increase of the energy. The model utilizes a three-dimensional formalism based on the Fermi-Eyges multiple scattering theory, with the introduction of modifications that takes into account the criation of secondary electrons. (Author) [pt

  7. Design of an electron injector for multi-stages laser wakefield acceleration

    International Nuclear Information System (INIS)

    Audet, T.

    2016-01-01

    Laser wakefield acceleration (LWFA) is a particle acceleration process relying on the interaction between high intensity laser pulses, of the order of 10 18 W/cm 2 and a plasma. The plasma wave generated in the laser wake sustain high amplitude electric fields (1- 100 GV/m). Those electric fields are 3 orders of magnitude higher than maximum electric fields in radio frequency cavities and represent the main benefit of LWFA, allowing more compact acceleration. However improvements of the LWFA-produced electron bunches properties, stability and repetition rate are mandatory for LWFA to be usable for applications. A scheme to improve electron bunches properties and to potentially increase the repetition rate is multi-stage LWFA. The laser plasma electron source, called the injector, has to produce relatively low energy (50 - 100 MeV), but high charge, small size and low divergence electron bunches. Produced electron bunches then have to be transported and injected into a second stage to increase electron kinetic energy. The subject of this thesis is to study and design a laser wakefield electron injector for multistage LWFA. In the frame of CILEX and the two-stages LWFA program, a prototype of the injector was built : ELISA consisting in a variable length gas cell. The plasma electronic density, which is a critical parameter for the control of the electron bunches properties, was characterized both experimentally and numerically. ELISA was used at 2 different laser facilities and physical mechanisms linked to electron bunches properties were studied in function of experimental parameters. A range of experimental parameters suitable for a laser wakefield injector was determined. A magnetic transport and diagnostic line was also built, implemented and tested at the UHI100 laser facility of the CEA Saclay. It allowed a more precise characterization of electron bunches generated with ELISA as well as an estimation of the quality of transported electron bunches for their

  8. Design and implementation of a device for measuring radiation energy of an electron accelerator

    International Nuclear Information System (INIS)

    Salhi, Heythem; Selmi, Samir

    2010-01-01

    Our work is part of a graduation project at the School of Technology and Computing, to obtain a master's degree in electrical engineering specialty industrial computer. Throughout the four-month internship at the National Center for Nuclear Science and Technology (CNSTN), we have learned to practice the knowledge acquired during the formative years and to manage our working time. Our job was to design and implementation of a device for measuring the energy of radiation. Our project meets the needs of users in the radio treatment Unit, which amount to automate measurement of radiation energy from the electron accelerator. This project has been beneficial on several levels: it was an opportunity to achieve better control of printed circuits, especially when they are dual layer and learning a new programming language that is actually BASIC. In human terms, this work has given us the opportunity to learn to manage our time, and learn teamwork. However, we are convinced that this project can be enhanced on various levels. It can be considered as a starting point of a contribution to the real-time measurement of the energy of radiation.

  9. Radiation environment in the tunnel of a high-energy proton accelerator at energies near 1 TeV

    International Nuclear Information System (INIS)

    McCaslin, J.B.; Sun, R.K.S.; Swanson, W.P.

    1987-12-01

    Neutron energy spectra, fluence distributions and rates in the FNAL Tevatron tunnel are summarized. This work has application to radiation damage to electronics and research equipment at high energy accelerators, as well as to radiological protection. 7 refs., 4 figs

  10. ELECTRON ACCELERATION IN PULSAR-WIND TERMINATION SHOCKS: AN APPLICATION TO THE CRAB NEBULA GAMMA-RAY FLARES

    Energy Technology Data Exchange (ETDEWEB)

    Kroon, John J.; Becker, Peter A.; Dermer, Charles D. [Department of Physics and Astronomy, George Mason University, Fairfax, VA 22030-4444 (United States); Finke, Justin D., E-mail: jkroon@gmu.edu, E-mail: pbecker@gmu.edu, E-mail: charlesdermer@outlook.com, E-mail: justin.finke@nrl.navy.mil [Space Science Division, Naval Research Laboratory, Washington, DC 20375 (United States)

    2016-12-20

    The γ -ray flares from the Crab Nebula observed by AGILE and Fermi -LAT reaching GeV energies and lasting several days challenge the standard models for particle acceleration in pulsar-wind nebulae because the radiating electrons have energies exceeding the classical radiation-reaction limit for synchrotron. Previous modeling has suggested that the synchrotron limit can be exceeded if the electrons experience electrostatic acceleration, but the resulting spectra do not agree very well with the data. As a result, there are still some important unanswered questions about the detailed particle acceleration and emission processes occurring during the flares. We revisit the problem using a new analytical approach based on an electron transport equation that includes terms describing electrostatic acceleration, stochastic wave-particle acceleration, shock acceleration, synchrotron losses, and particle escape. An exact solution is obtained for the electron distribution, which is used to compute the associated γ -ray synchrotron spectrum. We find that in our model the γ -ray flares are mainly powered by electrostatic acceleration, but the contributions from stochastic and shock acceleration play an important role in producing the observed spectral shapes. Our model can reproduce the spectra of all the Fermi -LAT and AGILE flares from the Crab Nebula, using magnetic field strengths in agreement with the multi-wavelength observational constraints. We also compute the spectrum and duration of the synchrotron afterglow created by the accelerated electrons, after they escape into the region on the downstream side of the pulsar-wind termination shock. The afterglow is expected to fade over a maximum period of about three weeks after the γ -ray flare.

  11. Beam dynamics study of a 30 MeV electron linear accelerator to drive a neutron source

    Science.gov (United States)

    Kumar, Sandeep; Yang, Haeryong; Kang, Heung-Sik

    2014-02-01

    An experimental neutron facility based on 32 MeV/18.47 kW electron linac has been studied by means of PARMELA simulation code. Beam dynamics study for a traveling wave constant gradient electron accelerator is carried out to reach the preferential operation parameters (E = 30 MeV, P = 18 kW, dE/E E-gun, pre-buncher, buncher, and 2 accelerating columns. A disk-loaded, on-axis-coupled, 2π/3-mode type accelerating rf cavity is considered for this linac. After numerous optimizations of linac parameters, 32 MeV beam energy is obtained at the end of the linac. As high electron energy is required to produce acceptable neutron flux. The final neutron flux is estimated to be 5 × 1011 n/cm2/s/mA. Future development will be the real design of a 30 MeV electron linac based on S band traveling wave.

  12. 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.

  13. Shielding Calculations for Industrial 5/7.5MeV Electron Accelerators Using the MCNP Monte Carlo Code

    International Nuclear Information System (INIS)

    Peri, E.; Orion, I.

    2014-01-01

    High energy X-rays from accelerators are used to irradiate food ingredients to prevent growth and development of unwanted biological organisms in food, in order to extend the shelf life of products. High energy photons can cause food activation due to (D 3 ,n) reactions. Until 2004, to eliminate the possibility of food activation, the electron energy was limited to 5 MeV X-rays for food irradiation. In 2004, the FDA approved the usage of up to 7.5 MeV, but only with tantalum and gold targets (1). Higher X-ray energy results an increased flux of X-rays in the forward direction, increased penetration, and higher photon dose rate due to better electron-to-photon conversion. These improvements could decrease the irradiation time and allow irradiation of larger packages, thereby providing higher production rates with lower treatment cost. Medical accelerators usually work with 6-18 MV electron energy with tungsten target to convert the electron beam to X-rays. In order to protect the patients, the accelerator head is protected with a heavy lead shielding; therefore, the bremsstrahlung is emitted only in the forward direction. There are many publications and standards that guide how to design optimal shielding for medical accelerator rooms. The shielding data for medical accelerators is not applicable for industrial accelerators, since the data is for different conversion targets, different X-Ray energies, and only for the forward direction. Collimators are not always in use in industrial accelerators, and therefore bremsstrahlung photons can be emitted in all directions. The bremsstrahlung spectrum and dose rate change as a function of the emission angle. The dose rate decreases from maximum in the forward direction (0°) to minimum at 180° by 1-2 orders of magnitude. In order to design and calculate optimal shielding for food accelerator rooms, there is a need to have the bremsstrahlung spectrum data, dose rates and concrete attenuation data in all emission directions

  14. Application of PIN photodiodes on the detection of X-rays generated in an electron accelerator

    International Nuclear Information System (INIS)

    Mondragon-Contreras, L.; Ramirez-Jimenez, F.J.; Garcia-Hernandez, J.M.; Torres-Bribiesca, M.A.; Lopez-Callejas, R.; Aguilera-Reyes, E.F.; Pena-Eguiluz, R.; Lopez-Valdivia, H.; Carrasco-Abrego, H.

    2009-01-01

    PIN photodiodes are used in a novel application for the determination, within the energy range from 90 to 485 keV, of the intensity of X-rays generated by an experimental electron accelerator. An easily assembled X-ray monitor has been built with a low-cost PIN photodiode and operational amplifiers. The output voltage signal obtained from this device can be related to the electron beam current and the accelerating voltage of the accelerator in order to estimate the dose rate delivered by bremsstrahlung.

  15. Decomposition of PCBs in transformer oil using an electron beam accelerator

    Science.gov (United States)

    Jung, In-Ha; Lee, Myun-Joo; Mah, Yoon-Jung

    2012-07-01

    Decomposition of PCBs in commercially used transformer oil used for more than 30 years has been carried out at normal temperature and pressure without any additives using an electron beam accelerator. The experiments were carried out in two ways: batch and continuous pilot plant with 1.5 MeV of energy, a 50 mA current, and 75 kW of power in a commercial scale accelerator. The electron beam irradiation seemed to transform large molecular weight compounds into lower ones, but the impact was considered too small on the physical properties of oil. Residual concentrations of PCBs after irradiation depend on the absorption dose of the electron beam energy, but aliphatic chloride compounds were produced at higher doses of irradiation. As the results from FT-NMR, chloride ions decomposed from the PCBs are likely to react with aliphatic hydro carbon compounds rather than existing as free radical ions in the transformer oil. Since this is a dry process, treated oil can be used as cutting oil or machine oil for heavy equipment without any additional treatments.

  16. Generation of intense spin-polarized electron beams at the electron accelerator facility ELSA

    International Nuclear Information System (INIS)

    Heiliger, Dominik

    2014-08-01

    The inverted source of polarized electrons at the electron accelerator ELSA in Bonn routinely provides a pulsed and low energetic beam of polarized electrons (100 mA, 48 keV) by irradiating a GaAs strained-layer superlattice photocathode with laser light. Due to the beam energy of 48 keV the beam transport to the linear accelerator is strongly space charge dominated and the actual beam current has an impact on the beam dynamics. Thus, the optics of the transfer line to the linear accelerator must be optimized with respect to the chosen beam intensity. An intensity upgrade including numerical simulations of the beam transport as well as a generation and a transport of a beam current of nearly 200 mA was successfully operated. In order to enhance the reliability and uptime of the source, a new extreme high vacuum load lock system was installed and commissioned. It consists of an activation chamber for heat cleaning of the photocathodes and activation with cesium and oxygen, a storage in which different types of photocathodes can be stored and a loading chamber in which an atomic hydrogen source is used to remove nearly any remaining surface oxidation. The new cleaning procedure with atomic hydrogen was investigated regarding its potential to restore the initial quantum efficiency of the photocathode after many activations.

  17. Optimization of laser parameters to obtain high-energy, high-quality electron beams through laser-plasma acceleration

    International Nuclear Information System (INIS)

    Samant, Sushil Arun; Sarkar, Deepangkar; Krishnagopal, Srinivas; Upadhyay, Ajay K.; Jha, Pallavi

    2010-01-01

    The propagation of an intense (a 0 =3), short-pulse (L∼λ p ) laser through a homogeneous plasma has been investigated. Using two-dimensional simulations for a 0 =3, the pulse-length and spot-size at three different plasma densities were optimized in order to get a better quality beam in laser wakefield accelerator. The study reveals that with increasing pulse-length the acceleration increases, but after a certain pulse-length (L>0.23λ p ) the emittance blows-up unacceptably. For spot-sizes less than that given by k p0 r s =2√(a 0 ), trapping is poor or nonexistent, and the optimal spot-size is larger. The deviation of the optimal spot-size from this formula increases as the density decreases. The efficacy of these two-dimensional simulations has been validated by running three-dimensional simulations at the highest density. It has been shown that good quality GeV-class beams can be obtained at plasma densities of ∼10 18 cm -3 . The quality of the beam can be substantially improved by selecting only the high-energy peak; in this fashion an energy-spread of better than 1% and a current in tens of kA can be achieved, which are important for applications such as free-electron lasers.

  18. Electron Acceleration in Wakefield and Supra-Bubble Regimes by Ultraintense Laser with Asymmetric Pulse

    International Nuclear Information System (INIS)

    Maimaitiaili, Bake; Sayipjamal, Dulat; Aimierding, Aimidula; Xie Baisong

    2011-01-01

    Electron acceleration in plasma driven by circular polarized ultraintense laser with asymmetric pulse are investigated analytically and numerically in terms of oscillation-center Hamiltonian formalism. Studies include wakefield acceleration, which dominates in blow-out or bubble regime and snow-plow acceleration which dominates in supra-bubble regime. By a comparison with each other it is found that snow-plow acceleration has lower acceleration capability. In wakefield acceleration, there exists an obvious optimum pulse asymmetry or/and pulse lengths that leads to the high net energy gain while in snow-plow acceleration it is insensitive to the pulse lengths. Power and linear scaling laws for wakefield and snow-plow acceleration respetively are observed from the net energy gain depending on laser field amplitude. Moreover, there exists also an upper and lower limit on plasma density for an effective acceleration in both of regimes. (physics of gases, plasmas, and electric discharges)

  19. Standing-wave free-electron laser two-beam accelerator

    International Nuclear Information System (INIS)

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

    1991-01-01

    A free-electron laser (FEL) two-beam accelerator (TBA) is proposed, in which the FEL interaction takes place in a series of drive cavities, rather than in a waveguide. Each drive cavity is 'beat-coupled' to a section of the accelerating structure. This standing-wave TBA is investigated theoretically and numerically, with analyses included of microwave extraction, growth of the FEL signal through saturation, equilibrium longitudinal beam dynamics following saturation, and sensitivity of the microwave amplitude and phase to errors in current and energy. It is found that phase errors due to current jitter are substantially reduced from previous versions of the TBA. Analytic scalings and numerical simulations are used to obtain an illustrative TBA parameter set. (orig.)

  20. Accelerators of future generation

    International Nuclear Information System (INIS)

    Kolomenskij, A.A.

    1983-01-01

    A brief review of the prospects of development of various of types accelerator over next 10 to 15 years is given. The following directions are considered: superhign energy proton accelerators and storage rings, electron-positron colliding beams, heavy ion accelerators, medium energy, high-current proton accelerators superhigh power particle beams (electrons light- and heavy ions) for inertial fusion

  1. Final report to US Department of Energy: Cyclotron autoresonance accelerator for electron beam dry scrubbing of flue gases

    Energy Technology Data Exchange (ETDEWEB)

    Hirshfield, J.L.

    2001-05-25

    Several designs have been built and operated of microwave cyclotron autoresonance accelerators (CARA's) with electron beam parameters suitable for remediation of pollutants in flue gas emissions from coal-burning power plants. CARA designs have also been developed with a TW-level 10.6 micron laser driver for electron acceleration from 50 to 100 MeV, and with UHF drivers for proton acceleration to over 500 MeV. Dose requirements for reducing SO2, NOx, and particulates in flue gas emissions to acceptable levels have been surveyed, and used to optimize the design of an electron beam source to deliver this dose.

  2. Electron accelerator technology research in food irradiation

    International Nuclear Information System (INIS)

    Jin Jianqiao; Ye Mingyang; Zhang Yue; Yang Bin; Xu Tao; Kong Xiangshan

    2014-01-01

    Electronic accelerator was applied to instead of cobalt sources for food irradiation, to keep food quality and to improve the effect of the treatment. Appropriate accelerator parameters lead to optimal technique. The irradiation effect is associated with the relationship between uniformity and irradiating speed, the effect of cargo size on radiation penetration, as well as other factors that affect the irradiation effects. Industrialization of electron accelerator irradiation will be looked to the future. (authors)

  3. SIS: an accelerator installation for heavy ions of high energy

    International Nuclear Information System (INIS)

    The two major sections of the report cover the scientific experimental program and the accelerator installation. Topics covered in the first include: heavy ion physics in the medium energy region; nuclear physics at relativistic energies; atomic physics loss and capture cross sections for electrons; spectroscopy of few-electron systems; atomic collision processes; biological experiments; nuclear track techniques in biology; and experiments with protons and secondary radiation. The second includes: concept for the total installation; technical description of the SIS 12; technical description of the SIS 100; status of the UNILAC injector; development options for the SIS installations; properties of the heavy ion beam; and structural work and technical supply provisions. In this SIS project proposal, an accelerator installation based on two synchrotrons is described with which atomic nuclei up to uranium can be accelerated to energies of more than 10 GeV/μ. With the SIS 12, which is the name of the first stage, heavy ion physics at intermediate energies can be pursued up to 500 MeV/μ. The second stage, a larger synchrotron, the SIS 100, has a diameter of 250 m. With this device, it is proposed to open up the domain of relativistic heavy ion physics up to 14 GeV/μ (for intermediate mass particles) and 10 GeV/μ (for uranium)

  4. Critical system issues and modeling requirements - the problem of beam energy sweep in an electron linear induction accelerator

    International Nuclear Information System (INIS)

    Turner, W.C.; Barrett, D.M.; Sampayan, S.E.

    1991-01-01

    In this paper the authors attempt to motivate the development of modeling tools for linear induction accelerator components by giving examples of performance limitations related to energy sweep. The most pressing issues is the development of an accurate model of the switching behavior of large magnetic cores at high dB/dt in the accelerator and magnetic compression modulators. Ideally one would like to have a model with as few parameters as possible that allows the user to choose the core geometry and magnetic material and perhaps a few parameters characterizing the switch model. Beyond this, the critical modeling tasks are: simulation of a magnetic compression modulator, modeling the reset dynamics of a magnetic compression modulator, modeling the loading characteristics of a linear induction accelerator cell, and modeling the electron injector current including the dynamics of feedback modulation and beam loading in an accelerator cell. Of course in the development of these models care should be given to benchmarking them against data from experimental systems. Beyond that one should aim for tools that have predictive power so that they can be used as design tools and not merely to replicate existing data

  5. WE-G-BRD-09: Novel MRI Compatible Electron Accelerator for MRI-Linac Radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Whelan, B; Keall, P [University of Sydney, Sydney (Australia); Gierman, S; Schmerge, J [SLAC National Accelerator Laboratory, Palo Alto, CA (United States); Holloway, L [Ingham Institute, Sydney, NSW (Australia); Fahrig, R [Stanford University, Stanford, CA (United States)

    2015-06-15

    Purpose: MRI guided radiotherapy is a rapidly growing field; however current linacs are not designed to operate in MRI fringe fields. As such, current MRI- Linac systems require magnetic shielding, impairing MR image quality and system flexibility. Here, we present a bespoke electron accelerator concept with robust operation in in-line magnetic fields. Methods: For in-line MRI-Linac systems, electron gun performance is the major constraint on accelerator performance. To overcome this, we propose placing a cathode directly within the first accelerating cavity. Such a configuration is used extensively in high energy particle physics, but not previously for radiotherapy. Benchmarked computational modelling (CST, Darmstadt, Germany) was employed to design and assess a 5.5 cell side coupled accelerator with a temperature limited thermionic cathode in the first accelerating cell. This simulation was coupled to magnetic fields from a 1T MRI model to assess robustness in magnetic fields for Source to Isocenter Distance between 1 and 2 meters. Performance was compared to a conventional electron gun based system in the same magnetic field. Results: A temperature limited cathode (work function 1.8eV, temperature 1245K, emission constant 60A/K/cm{sup 2}) will emit a mean current density of 24mA/mm{sup 2} (Richardson’s Law). We modeled a circular cathode with radius 2mm and mean current 300mA. Capture efficiency of the device was 43%, resulting in target current of 130 mA. The electron beam had a FWHM of 0.2mm, and mean energy of 5.9MeV (interquartile spread of 0.1MeV). Such an electron beam is suitable for radiotherapy, comparing favourably to conventional systems. This model was robust to operation the MRI fringe field, with a maximum current loss of 6% compared to 85% for the conventional system. Conclusion: The bespoke electron accelerator is robust to operation in in-line magnetic fields. This will enable MRI-Linacs with no accelerator magnetic shielding, and minimise

  6. Stray-electron accumulation and effects in HIF accelerators

    International Nuclear Information System (INIS)

    Cohen, R.H.; Friedman, A.; Furman, M.A.; Lund, S.M.; Molvik, A.W.; Stoltz, P.; Vay, J.-L.

    2003-01-01

    Stray electrons can be introduced in positive-charge accelerators for heavy ion fusion (or other applications) as a result of ionization of ambient gas or gas released from walls due to halo-ion impact, or as a result of secondary-electron emission. Electron accumulation is impacted by the ion beam potential, accelerating fields, multipole magnetic fields used for beam focus, and the pulse duration. We highlight the distinguishing features of heavy-ion accelerators as they relate to stray-electron issues, and present first results from a sequence of simulations to characterize the electron cloud that follows from realistic ion distributions. Also, we present ion simulations with prescribed random electron distributions, undertaken to begin to quantify the effects of electrons on ion beam quality

  7. Ultrafast Diagnostics for Electron Beams from Laser Plasma Accelerators

    International Nuclear Information System (INIS)

    Matlis, N.H.; Bakeman, M.; Geddes, C.G.R.; Gonsalves, T.; Lin, C.; Nakamura, K.; Osterhoff, J.; Plateau, G.R.; Schroeder, C.B.; Shiraishi, S.; Sokollik, T.; van Tilborg, J.; Toth, Cs.; Leemans, W.P.

    2010-01-01

    We present an overview of diagnostic techniques for measuring key parameters of electron bunches from Laser Plasma Accelerators (LPAs). The diagnostics presented here were chosen because they highlight the unique advantages (e.g., diverse forms of electromagnetic emission) and difficulties (e.g., shot-to-shot variability) associated with LPAs. Non destructiveness and high resolution (in space and time and energy) are key attributes that enable the formation of a comprehensive suite of simultaneous diagnostics which are necessary for the full characterization of the ultrashort, but highly-variable electron bunches from LPAs.

  8. Ultrafast Diagnostics for Electron Beams from Laser Plasma Accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Matlis, N. H.; Bakeman, M.; Geddes, C. G. R.; Gonsalves, T.; Lin, C.; Nakamura, K.; Osterhoff, J.; Plateau, G. R.; Schroeder, C. B.; Shiraishi, S.; Sokollik, T.; van Tilborg, J.; Toth, Cs.; Leemans, W. P.

    2010-06-01

    We present an overview of diagnostic techniques for measuring key parameters of electron bunches from Laser Plasma Accelerators (LPAs). The diagnostics presented here were chosen because they highlight the unique advantages (e.g., diverse forms of electromagnetic emission) and difficulties (e.g., shot-to-shot variability) associated with LPAs. Non destructiveness and high resolution (in space and time and energy) are key attributes that enable the formation of a comprehensive suite of simultaneous diagnostics which are necessary for the full characterization of the ultrashort, but highly-variable electron bunches from LPAs.

  9. The electron accelerator for the AWAKE experiment at CERN

    Energy Technology Data Exchange (ETDEWEB)

    Pepitone, K., E-mail: kevin.pepitone@cern.ch [CERN, Geneva (Switzerland); Doebert, S., E-mail: steffen.doebert@cern.ch [CERN, Geneva (Switzerland); Burt, G. [The University of Lancaster, Lancaster (United Kingdom); Chevallay, E.; Chritin, N.; Delory, C.; Fedosseev, V.; Hessler, Ch.; McMonagle, G. [CERN, Geneva (Switzerland); Mete, O. [The University of Manchester, Manchester (United Kingdom); Verzilov, V. [Triumf, Vancouver (Canada); Apsimon, R. [The University of Lancaster, Lancaster (United Kingdom)

    2016-09-01

    The AWAKE collaboration prepares a proton driven plasma wakefield acceleration experiment using the SPS beam at CERN. A long proton bunch extracted from the SPS interacts with a high power laser and a 10 m long rubidium vapour plasma cell to create strong wakefields allowing sustained electron acceleration. The electron bunch to probe these wakefields is supplied by a 20 MeV electron accelerator. The electron accelerator consists of an RF-gun and a short booster structure. This electron source should provide beams with intensities between 0.1 and 1 nC, bunch lengths between 0.3 and 3 ps and an emittance of the order of 2 mm mrad. The wide range of parameters should cope with the uncertainties and future prospects of the planned experiments. The layout of the electron accelerator, its instrumentation and beam dynamics simulations are presented.

  10. Free electron lasers for transmission of energy in space

    Science.gov (United States)

    Segall, S. B.; Hiddleston, H. R.; Catella, G. C.

    1981-01-01

    A one-dimensional resonant-particle model of a free electron laser (FEL) is used to calculate laser gain and conversion efficiency of electron energy to photon energy. The optical beam profile for a resonant optical cavity is included in the model as an axial variation of laser intensity. The electron beam profile is matched to the optical beam profile and modeled as an axial variation of current density. Effective energy spread due to beam emittance is included. Accelerators appropriate for a space-based FEL oscillator are reviewed. Constraints on the concentric optical resonator and on systems required for space operation are described. An example is given of a space-based FEL that would produce 1.7 MW of average output power at 0.5 micrometer wavelength with over 50% conversion efficiency of electrical energy to laser energy. It would utilize a 10 m-long amplifier centered in a 200 m-long optical cavity. A 3-amp, 65 meV electrostatic accelerator would provide the electron beam and recover the beam after it passes through the amplifier. Three to five shuttle flights would be needed to place the laser in orbit.

  11. Industrial use of electron accelerators

    International Nuclear Information System (INIS)

    Tabata, Y.

    1980-01-01

    Use of accelerators in various fields of Japan is reviewed. The total number of accelerators in Japan and its relation with others fields, the number of accelerators for use in radiation processing, comparison between the use of low and high energy machines, etc... is done. (E.G.) [pt

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

    Science.gov (United States)

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

    2018-04-01

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

  13. Comparison of measured with calculated dose distribution from a 120-MeV electron beam from a laser-plasma accelerator

    International Nuclear Information System (INIS)

    Lundh, O.; Rechatin, C.; Faure, J.; Ben-Ismaïl, A.; Lim, J.; De Wagter, C.; De Neve, W.; Malka, V.

    2012-01-01

    Purpose: To evaluate the dose distribution of a 120-MeV laser-plasma accelerated electron beam which may be of potential interest for high-energy electron radiation therapy. Methods: In the interaction between an intense laser pulse and a helium gas jet, a well collimated electron beam with very high energy is produced. A secondary laser beam is used to optically control and to tune the electron beam energy and charge. The potential use of this beam for radiation treatment is evaluated experimentally by measurements of dose deposition in a polystyrene phantom. The results are compared to Monte Carlo simulations using the geant4 code. Results: It has been shown that the laser-plasma accelerated electron beam can deliver a peak dose of more than 1 Gy at the entrance of the phantom in a single laser shot by direct irradiation, without the use of intermediate magnetic transport or focusing. The dose distribution is peaked on axis, with narrow lateral penumbra. Monte Carlo simulations of electron beam propagation and dose deposition indicate that the propagation of the intense electron beam (with large self-fields) can be described by standard models that exclude collective effects in the response of the material. Conclusions: The measurements show that the high-energy electron beams produced by an optically injected laser-plasma accelerator can deliver high enough dose at penetration depths of interest for electron beam radiotherapy of deep-seated tumors. Many engineering issues must be resolved before laser-accelerated electrons can be used for cancer therapy, but they also represent exciting challenges for future research.

  14. Direct acceleration of electrons by a CO2 laser in a curved plasma waveguide

    CERN Document Server

    Yi, Longqing; Shen, Baifei

    2016-01-01

    Laser plasma interaction with micro-engineered targets at relativistic intensities has been greatly promoted by recent progress in the high contrast lasers and the manufacture of advanced micro- and nano-structures. This opens new possibilities for the physics of laser-matter interaction. Here we propose a novel approach that leverages the advantages of high-pressure CO 2 laser, laser-waveguide interaction, as well as micro-engineered plasma structure to accelerate electrons to peak energy greater than 1 GeV with narrow slice energy spread (~1%) and high overall efficiency. The acceleration gradient is 26 GV/m for a 1.3 TW CO2 laser system. The micro-bunching of a long electron beam leads to the generation of a chain of ultrashort electron bunches with the duration roughly equal to half-laser-cycle. These results open a way for developing a compact and economic electron source for diverse applications.

  15. Longitudinal Jitter Analysis of a Linear Accelerator Electron Gun

    Directory of Open Access Journals (Sweden)

    MingShan Liu

    2016-11-01

    Full Text Available We present measurements and analysis of the longitudinal timing jitter of a Beijing Electron Positron Collider (BEPCII linear accelerator electron gun. We simulated the longitudinal jitter effect of the gun using PARMELA to evaluate beam performance, including: beam profile, average energy, energy spread, and XY emittances. The maximum percentage difference of the beam parameters is calculated to be 100%, 13.27%, 42.24% and 65.01%, 86.81%, respectively. Due to this, the bunching efficiency is reduced to 54%. However, the longitudinal phase difference of the reference particle was 9.89°. The simulation results are in agreement with tests and are helpful to optimize the beam parameters by tuning the trigger timing of the gun during the bunching process.

  16. Electron cloud dynamics in the Cornell Electron Storage Ring Test Accelerator wiggler

    Directory of Open Access Journals (Sweden)

    C. M. Celata

    2011-04-01

    Full Text Available The interference of stray electrons (also called “electron clouds” with accelerator beams is important in modern intense-beam accelerators, especially those with beams of positive charge. In magnetic wigglers, used, for instance, for transverse emittance damping, the intense synchrotron radiation produced by the beam can generate an electron cloud of relatively high density. In this paper the complicated dynamics of electron clouds in wigglers is examined using the example of a wiggler in the Cornell Electron Storage Ring Test Accelerator experiment at the Cornell Electron Storage Ring. Three-dimensional particle-in-cell simulations with the WARP-POSINST computer code show different density and dynamics for the electron cloud at locations near the maxima of the vertical wiggler field when compared to locations near the minima. Dynamics in these regions, the electron cloud distribution vs longitudinal position, and the beam coherent tune shift caused by the wiggler electron cloud will be discussed.

  17. Calorimetry at industrial electron accelerators

    DEFF Research Database (Denmark)

    Miller, Arne; Kovacs, A.

    1985-01-01

    Calorimetry is a convenient way to measure doses at industrial electron accelerators, where high absorbed doses (1-100 kGy) are delivered at dose rates of 102-105 Gy s-1 or even higher. Water calorimeters have been used for this purpose for several years, but recently other materials such as grap......Calorimetry is a convenient way to measure doses at industrial electron accelerators, where high absorbed doses (1-100 kGy) are delivered at dose rates of 102-105 Gy s-1 or even higher. Water calorimeters have been used for this purpose for several years, but recently other materials...

  18. Acceleration of a trailing positron bunch in a plasma wakefield accelerator

    International Nuclear Information System (INIS)

    Doche, A.; Beekman, C.; Corde, S.

    2017-01-01

    High gradients of energy gain and high energy efficiency are necessary parameters for compact, cost-efficient and high-energy particle colliders. Plasma Wakefield Accelerators (PWFA) offer both, making them attractive candidates for next-generation colliders. Here in these devices, a charge-density plasma wave is excited by an ultra-relativistic bunch of charged particles (the drive bunch). The energy in the wave can be extracted by a second bunch (the trailing bunch), as this bunch propagates in the wake of the drive bunch. While a trailing electron bunch was accelerated in a plasma with more than a gigaelectronvolt of energy gain, accelerating a trailing positron bunch in a plasma is much more challenging as the plasma response can be asymmetric for positrons and electrons. We report the demonstration of the energy gain by a distinct trailing positron bunch in a plasma wakefield accelerator, spanning nonlinear to quasi-linear regimes, and unveil the beam loading process underlying the accelerator energy efficiency. A positron bunch is used to drive the plasma wake in the experiment, though the quasi-linear wake structure could as easily be formed by an electron bunch or a laser driver. Finally, the results thus mark the first acceleration of a distinct positron bunch in plasma-based particle accelerators.

  19. Radiosensitivity of chlorella after medium energy accelerated electron irradiation; Radiosensibilite des chlorelles aux electrons acceleres de moyenne energie

    Energy Technology Data Exchange (ETDEWEB)

    Roux, J C [commissariat a L' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

    1966-06-01

    The survival curves (capability of multiplication) of chlorella pyrenoidosa after irradiations can be used for soft electrons (0.65 and 1 MeV), hence penetrating into only 2 to 4 millimeters of water: the algae are laying on porous membranes and the doses are calculated from the power of the electron beam measured by the electric current on a metallic target or by Fricke's dosimetry. With these techniques, it is showed and discussed the part of anoxia in the radioprotection (magnitude or reduction of the dose calculated from the slope of survival curves: 2.5 ) that is more important than the restoration studied by the fractionation of the dose. The 0.65 and 1 MeV electrons have a biologic effect lesser than 180 keV X-rays (RBE - relative biological efficiency - calculated on the slope of survival curves is 0.92 in aerated irradiation, 0.56 in the deoxygenated irradiation). (author) [French] Les courbes de survie clonale (capacite de multiplication) de chlorella pyrenoidosa apres irradiation sont realisables meme avec des electrons peu energetiques (0.65 et 1 MeV), donc peu penetrants, par l'irradiation d'algues deposees sur membrane filtrante et grace au calcul de la dose a partir de l'energie du faisceau mesure par le courant que celui-ci cree dans une cible metallique ou par dosimetrie de Fricke. Par ces techniques, on a montre et discute le role de l'anoxie dans la radioprotection des chlorelles (facteur de reduction de la dose calcule sur la pente des courbes de survie de 2.5) qui est plus important que le pouvoir de restauration etudie par le fractionnement de la dose. Les electrons utilises ont un effet biologique moins grand que les rayons X de 180 keV (l'efficacite biologique relative - EBR - calculee sur la pente des courbes de survie est de 0.9 en presence d'air, 0.6 en presence d'azote)

  20. On the quasi-monoenergetic electron beam generation in the laser wakefield acceleration

    International Nuclear Information System (INIS)

    Bulanov, S.V.; Tajima, Toshiki

    2005-01-01

    A new phase of laser acceleration research has entered, as signified by the recent reports in Nature 9/30/05 of the generation of quasi-monoenergetic electron beam by laser wakefield acceleration in three experiments. We survey the current status of experiments and offer their theoretical interpretation. We understand why the choice of parameters is of such importance and why the earlier experiments showed energy spectra far from monoenergy. (author)

  1. Subharmonic beam-loading in electron linear accelerators

    International Nuclear Information System (INIS)

    Gallagher, W.J.

    1983-01-01

    The intention of operating an electron linear accelerator subharmonically beam loaded for free electron laser application requires justification of the beam-loaded energy gain equation. The mode of operation typically planned is 5 to 10 nanocoulombs single RF cycle pulses at 25 to 50 nanosecond intervals. This inquiry investigates the details of this sort of beam loading and discusses the performance achievable. Several other investigations of single bunch beam loading have been undertaken, notably at SLAC, where it has been found experimentally that the beam-loading varies directly as the bunch charge and independently of its energy; that investigation also included radiation effects of the wake field and losses owing to parasitic effects of higher order modes. In the case of beam loading where there are multiple pulses transiting at the same time, and spaced far enough apart that significant RF power is introduced between pulses, the energy gain may be calculated by dividing the waveguide into a number of segments, each equal in length to the integral of the interpulse time and the local group velocity. Equations which reveal that the net energy gain in the steady state is the sum of the energy gains in these segments, which compute the initial field intensity, and which calculate the energy gain in the subharmonic case on the basis of the equivalent beam current are presented

  2. Improvement of the quality of laser-wakefield accelerators: towards a compact free-electron laser

    International Nuclear Information System (INIS)

    Lehe, R.

    2014-01-01

    When an intense and short laser pulse propagates through an underdense gas, it can accelerate a fraction of the electrons of the gas, and thereby generate an electron bunch with an energy of a few hundreds of MeV. This phenomenon, which is referred to as laser-wakefield acceleration, has many potential applications, including the design of ultra-bright X-ray sources known as free electron lasers (FEL). However, these applications require the electron bunch to have an excellent quality (low divergence, emittance and energy spread). In this thesis, different solutions to improve the quality of the electron bunch are developed, both analytically and through the use of Particle-In-Cell (PIC) simulations. It is first shown however that PIC simulations tend to erroneously overestimate the emittance of the bunch, due to the numerical Cherenkov effect. Thus, in order to correctly estimate the emittance, a modified PIC algorithm is proposed, which is not subject to this unphysical Cherenkov effect. Using this algorithm, we have observed and studied a new mechanism to generate the electron bunch: optical transverse injection. This mechanism can produce bunches with a high charge, a low emittance and a low energy spread. In addition, we also proposed an experimental setup - the laser-plasma lens - which can strongly reduce the final divergence of the bunch. Finally, these results are put into context by discussing the properties required for the design of a compact FEL. It is shown in particular that laser-wakefield accelerator could be advantageously combined with innovative laser-plasma undulators, in order to produce bright X-rays sources. (author)

  3. Accelerator Technology and High Energy Physic Experiments, WILGA 2012; EuCARD Sessions

    CERN Document Server

    Romaniuk, R S

    2012-01-01

    Wilga Sessions on HEP experiments, astroparticle physica and accelerator technology were organized under the umbrella of the EU FP7 Project EuCARD – European Coordination for Accelerator Research and Development. The paper is the second part (out of five) of the research survey of WILGA Symposium work, May 2012 Edition, concerned with accelerator technology and high energy physics experiments. It presents a digest of chosen technical work results shown by young researchers from different technical universities from this country during the XXXth Jubilee SPIE-IEEE Wilga 2012, May Edition, symposium on Photonics and Web Engineering. Topical tracks of the symposium embraced, among others, nanomaterials and nanotechnologies for photonics, sensory and nonlinear optical fibers, object oriented design of hardware, photonic metrology, optoelectronics and photonics applications, photonics-electronics co-design, optoelectronic and electronic systems for astronomy and high energy physics experiments, JET and pi-of-the ...

  4. The generation of high fields for particle acceleration to very high energies

    International Nuclear Information System (INIS)

    1985-01-01

    A Workshop organised by the CERN Accelerator School, the European Committee for Future Accelerators and the Istituto Nazionale di Fisica Nucleare was held at the Frascati laboratory of INFN during the last week of September 1984. Its purpose was to bring together an inter-disciplinary group of physicists to review ideas for the acceleration of particles to energies beyond those attainable in machines whose construction is underway, or is currently contemplated. These proceedings contain some of the material presented and discussed at the Workshop, comprising papers on topics such as: the free-electron-laser, the lasertron, wakefield accelerators, the laser excitation of droplet arrays, a switched-power linac, plasma beat-wave accelerators and the choice of basic parameters for linear colliders intended for the TeV energy region. (orig.)

  5. Nonponderomotive electron acceleration in ultrashort surface-plasmon fields

    Energy Technology Data Exchange (ETDEWEB)

    Racz, Peter; Dombi, Peter [Wigner Research Centre for Physics, Konkoly-Thege M. ut 29-33, H-1121 Budapest (Hungary)

    2011-12-15

    We investigate the nonponderomotive nature of ultrafast plasmonic electron acceleration in strongly decaying electromagnetic fields generated by few-cycle and single-cycle femtosecond laser pulses. We clearly identify the conditions contributing to nonponderomotive acceleration and establish fundamental scaling laws and carrier-envelope phase effects. These all-optically accelerated compact, femtosecond electron sources can be utilized in contemporary ultrafast methods.

  6. Electronics around the accelerators- mathematical recalls

    International Nuclear Information System (INIS)

    Le Meur, G.

    1992-02-01

    The author presents the main mathematical tools used in electronics and in particular in accelerator electronics: complex functions, distributions, Fourier series, Laplace transformation, Fourier transformation and probabilities

  7. Summary Report of Working Group 5: Electron Beam Driven Plasma Accelerators

    International Nuclear Information System (INIS)

    Hogan, Mark J.; Conde, Manoel E.

    2009-01-01

    Electron beam driven plasma accelerators have seen rapid progress over the last decade. Recent efforts have built on this success by constructing a concept for a plasma wakefield accelerator based linear collider. The needs for any future collider to deliver both energy and luminosity have substantial implications for interpreting current experiments and setting priorities for the future. This working group reviewed current experiments and ideas in the context of the demands of a future collider. The many discussions and presentations are summarized here.

  8. Overview of the low energy accelerator scanning system

    International Nuclear Information System (INIS)

    Leo Kwee Wah; Lojius Lombigit; Muhamad Zahidee Taat; Abu Bakar Ghazali; Mohd Rizal Ibrahim; Mohd Rizal Chulan Md Chulan; Azaman Ahmad; Abdul Halim Baijan; Rokiah Mohd Sabri

    2009-01-01

    This paper describes the specification of the low energy accelerator (Baby-EBM; Electron Beam Machine) scanning system. It comprises a discussion of coil inductance measurement, power supply design and the test results. The scanning horn system was completely assembled and tested; it was found that the system is able to scan the beam across the scanning window with a required beam profile. (Author)

  9. Application of Plasma Waveguides to High Energy Accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Milchberg, Howard M

    2013-03-30

    The eventual success of laser-plasma based acceleration schemes for high-energy particle physics will require the focusing and stable guiding of short intense laser pulses in reproducible plasma channels. For this goal to be realized, many scientific issues need to be addressed. These issues include an understanding of the basic physics of, and an exploration of various schemes for, plasma channel formation. In addition, the coupling of intense laser pulses to these channels and the stable propagation of pulses in the channels require study. Finally, new theoretical and computational tools need to be developed to aid in the design and analysis of experiments and future accelerators. Here we propose a 3-year renewal of our combined theoretical and experimental program on the applications of plasma waveguides to high-energy accelerators. During the past grant period we have made a number of significant advances in the science of laser-plasma based acceleration. We pioneered the development of clustered gases as a new highly efficient medium for plasma channel formation. Our contributions here include theoretical and experimental studies of the physics of cluster ionization, heating, explosion, and channel formation. We have demonstrated for the first time the generation of and guiding in a corrugated plasma waveguide. The fine structure demonstrated in these guides is only possible with cluster jet heating by lasers. The corrugated guide is a slow wave structure operable at arbitrarily high laser intensities, allowing direct laser acceleration, a process we have explored in detail with simulations. The development of these guides opens the possibility of direct laser acceleration, a true miniature analogue of the SLAC RF-based accelerator. Our theoretical studies during this period have also contributed to the further development of the simulation codes, Wake and QuickPIC, which can be used for both laser driven and beam driven plasma based acceleration schemes. We

  10. An inverse free electron laser accelerator experiment

    International Nuclear Information System (INIS)

    Wernick, I.; Marshall, T.C.

    1992-01-01

    A free electron laser was configured as an autoaccelerator to test the principle of accelerating electrons by stimulated absorption of radiation (λ = 1.65mm) by an electron beam (750kV) traversing an undulator. Radiation is produced in the first section of a constant period undulator (1 w1 = 1.43cm) and then absorbed (∼ 40%) in a second undulator, having a tapered period (1 w2 = 1.8 - 2.25cm), which results in the acceleration of a subgroup (∼ 9%) of electrons to ∼ 1MeV

  11. Effects of Shock and Turbulence Properties on Electron Acceleration

    Science.gov (United States)

    Qin, G.; Kong, F.-J.; Zhang, L.-H.

    2018-06-01

    Using test particle simulations, we study electron acceleration at collisionless shocks with a two-component model turbulent magnetic field with slab component including dissipation range. We investigate the importance of the shock-normal angle θ Bn, magnetic turbulence level {(b/{B}0)}2, and shock thickness on the acceleration efficiency of electrons. It is shown that at perpendicular shocks the electron acceleration efficiency is enhanced with the decrease of {(b/{B}0)}2, and at {(b/{B}0)}2=0.01 the acceleration becomes significant due to a strong drift electric field with long time particles staying near the shock front for shock drift acceleration (SDA). In addition, at parallel shocks the electron acceleration efficiency is increasing with the increase of {(b/{B}0)}2, and at {(b/{B}0)}2=10.0 the acceleration is very strong due to sufficient pitch-angle scattering for first-order Fermi acceleration, as well as due to the large local component of the magnetic field perpendicular to the shock-normal angle for SDA. On the other hand, the high perpendicular shock acceleration with {(b/{B}0)}2=0.01 is stronger than the high parallel shock acceleration with {(b/{B}0)}2=10.0, the reason might be the assumption that SDA is more efficient than first-order Fermi acceleration. Furthermore, for oblique shocks, the acceleration efficiency is small no matter whether the turbulence level is low or high. Moreover, for the effect of shock thickness on electron acceleration at perpendicular shocks, we show that there exists the bendover thickness, L diff,b. The acceleration efficiency does not noticeably change if the shock thickness is much smaller than L diff,b. However, if the shock thickness is much larger than L diff,b, the acceleration efficiency starts to drop abruptly.

  12. Dragon-I Linear Induction Electron Accelerator

    International Nuclear Information System (INIS)

    Ding Bonan; Deng Jianjun; Wang Huacen; Cheng Nian'an; Dai Guangsen; Zhang Linwen; Liu Chengjun; Zhang Wenwei; Li Jin; Zhang Kaizhi

    2005-01-01

    Dragon-I is a linear induction electron accelerator. This facility consists of a 3.6 MeV injector, 38 meter beam transport line and 16 MeV induction accelerator powered by high voltage generators, including 8 Marx generators and 48 Blumlein lines. This paper describes the physics design, development and experimental results of Dragon-I. The key technology is analyzed in the accelerator development, and the design requirements and operation of the major subsystems are presented. The experimental results show Dragon-I generates an 18-20 MeV, 2.5 kA, 70 ns electron beam. The X-ray spot size is about 1.2 mm and dose level about 0.103 C/kg at 1 meter. (authors)

  13. Estimation of the characteristic energy of electron precipitation

    Directory of Open Access Journals (Sweden)

    C. F. del Pozo

    2002-09-01

    Full Text Available Data from simultaneous observations (on 13 February 1996, 9 November 1998, and 12 February 1999 with the IRIS, DASI and EISCAT systems are employed in the study of the energy distribution of the electron precipitation during substorm activity. The estimation of the characteristic energy of the electron precipitation over the common field of view of IRIS and DASI is discussed. In particular, we look closely at the physical basis of the correspondence between the characteristic energy, the flux-averaged energy, as defined below, and the logarithm of the ratio of the green-light intensity to the square of absorption. This study expands and corrects results presented in the paper by Kosch et al. (2001. It is noticed, moreover, that acceleration associated with diffusion processes in the magnetosphere long before precipitation may be controlling the shape of the energy spectrum. We propose and test a "mixed" distribution for the energy-flux spectrum, exponential at the lower energies and Maxwellian or modified power-law at the higher energies, with a threshold energy separating these two regimes. The energy-flux spectrum at Tromsø, in the 1–320 keV range, is derived from EISCAT electron density profiles in the 70–140 km altitude range and is applied in the "calibration" of the optical intensity and absorption distributions, in order to extrapolate the flux and characteristic energy maps.Key words. Ionosphere (auroral ionosphere; particle precipitation; particle acceleration

  14. Estimation of the characteristic energy of electron precipitation

    Directory of Open Access Journals (Sweden)

    C. F. del Pozo

    Full Text Available Data from simultaneous observations (on 13 February 1996, 9 November 1998, and 12 February 1999 with the IRIS, DASI and EISCAT systems are employed in the study of the energy distribution of the electron precipitation during substorm activity. The estimation of the characteristic energy of the electron precipitation over the common field of view of IRIS and DASI is discussed. In particular, we look closely at the physical basis of the correspondence between the characteristic energy, the flux-averaged energy, as defined below, and the logarithm of the ratio of the green-light intensity to the square of absorption. This study expands and corrects results presented in the paper by Kosch et al. (2001. It is noticed, moreover, that acceleration associated with diffusion processes in the magnetosphere long before precipitation may be controlling the shape of the energy spectrum. We propose and test a "mixed" distribution for the energy-flux spectrum, exponential at the lower energies and Maxwellian or modified power-law at the higher energies, with a threshold energy separating these two regimes. The energy-flux spectrum at Tromsø, in the 1–320 keV range, is derived from EISCAT electron density profiles in the 70–140 km altitude range and is applied in the "calibration" of the optical intensity and absorption distributions, in order to extrapolate the flux and characteristic energy maps.

    Key words. Ionosphere (auroral ionosphere; particle precipitation; particle acceleration

  15. Results from the S-DALINAC: one year of operational experience from a superconducting electron accelerator

    International Nuclear Information System (INIS)

    Graef, H.D.; Horn, J.; Hummel, K.D.; Luettge, C.; Richter, A.; Riedorf, T.; Ruehl, K.; Schardt, P.; Spamer, E.; Stiller, A.; Thomas, F.; Titze, O.; Toepper, J.; Weise, H.; Winkler, T.

    1992-01-01

    Since August 1991 the superconducting cw-electron accelerator S-DALINAC at Darmstadt has produced single and multi pass beam which is used for different experiments. At energies below 10 MeV investigations of channeling radiation production and nuclear resonance fluorescence experiments are performed. Single pass operation yielding beam energies up to 40 MeV has been used for tests of the Free Electron Laser (FEL) beamline and for the investigation of spontaneous emission from the undulator. Two and three pass operation at higher energies produces beam for electron scattering experiments,(e,e') and (e,e'x), as well as for the production of channeling radiation. True cw operation allows for energies up to 84 MeV limited by the capacity of the He refrigerator. At higher energies the duty factor has to be reduced and pulse length is on the order of seconds. The successful operation of the entire accelerator was the result of several developments: six accelerating cavities fabricated from RRR = 280 niobium raised the average field gradient to 6 MV/m; the control systems for gun, rf, cavity tuners, and the beam transport system including beam diagnostics have been integrated into a reliable remote control of the S-DALINAC; and computer controlled path length adjustments for the two recirculating beamlines were installed for optimization of the reinjection phase. (Author) fig., tab., 10 refs

  16. Survey of physics research with a high duty cycle electron accelerator

    International Nuclear Information System (INIS)

    Bartholomew, G.A.; Earle, E.D.; Knowles, J.W.; Lone, M.A.

    1981-02-01

    The opportunities for nuclear physics research afforded by a CW electron linac with nominal energy 100 MeV and beam current >= 100 μA equipped with a bremsstrahlung monochromator and reaction product coincidence facilities are outlined. It is proposed that a program toward realization of an accelerator meeting these requirements and with provision for eventual extension to higher energies be undertaken at the Chalk River Nuclear Laboratories. (author)

  17. Dose properties of a laser accelerated electron beam and prospects for clinical application

    International Nuclear Information System (INIS)

    Kainz, K.K.; Hogstrom, K.R.; Antolak, J.A.; Almond, P.R.; Bloch, C.D.; Chiu, C.; Fomytskyi, M.; Raischel, F.; Downer, M.; Tajima, T.

    2004-01-01

    Laser wakefield acceleration (LWFA) technology has evolved to where it should be evaluated for its potential as a future competitor to existing technology that produces electron and x-ray beams. The purpose of the present work is to investigate the dosimetric properties of an electron beam that should be achievable using existing LWFA technology, and to document the necessary improvements to make radiotherapy application for LWFA viable. This paper first qualitatively reviews the fundamental principles of LWFA and describes a potential design for a 30 cm accelerator chamber containing a gas target. Electron beam energy spectra, upon which our dose calculations are based, were obtained from a uniform energy distribution and from two-dimensional particle-in-cell (2D PIC) simulations. The 2D PIC simulation parameters are consistent with those reported by a previous LWFA experiment. According to the 2D PIC simulations, only approximately 0.3% of the LWFA electrons are emitted with an energy greater than 1 MeV. We studied only the high-energy electrons to determine their potential for clinical electron beams of central energy from 9 to 21 MeV. Each electron beam was broadened and flattened by designing a dual scattering foil system to produce a uniform beam (103%>off-axis ratio>95%) over a 25x25 cm2 field. An energy window (ΔE) ranging from 0.5 to 6.5 MeV was selected to study central-axis depth dose, beam flatness, and dose rate. Dose was calculated in water at a 100 cm source-to-surface distance using the EGS/BEAM Monte Carlo algorithm. Calculations showed that the beam flatness was fairly insensitive to ΔE. However, since the falloff of the depth-dose curve (R 10 -R 90 ) and the dose rate both increase with ΔE, a tradeoff between minimizing (R 10 -R 90 ) and maximizing dose rate is implied. If ΔE is constrained so that R 10 -R 90 is within 0.5 cm of its value for a monoenergetic beam, the maximum practical dose rate based on 2D PIC is approximately 0.1 Gy min-1

  18. Energy Conversion Mechanism for Electron Perpendicular Energy in High Guide-Field Reconnection

    Science.gov (United States)

    Guo, Xuehan; Horiuchi, Ritoku; Kaminou, Yasuhiro; Cheng, Frank; Ono, Yasushi

    2016-10-01

    The energy conversion mechanism for electron perpendicular energy, both the thermal and the kinetic energy, is investigated by means of two-dimensional, full-particle simulations in an open system. It is shown that electron perpendicular heating is mainly due to the breaking of magnetic moment conservation in separatrix region because the charge separation generates intense variation of electric field within the electron Larmor radius. Meanwhile, electron perpendicular acceleration takes place manly due to the polarization drift term as well as the curvature drift term of E . u⊥ in the downstream near the X-point. The enhanced electric field due to the charge separation there results in a significant effect of the polarization drift term on the dissipation of magnetic energy within the ion inertia length in the downstream. Japan Society for the Promotion of Science (JSPS) Fellows 15J03758.

  19. Characteristics of an electron-beam rocket pellet accelerator

    International Nuclear Information System (INIS)

    Tsai, C.C.; Foster, C.A.; Schechter, D.E.

    1989-01-01

    An electron-beam rocket pellet accelerator has been designed, built, assembled, and tested as a proof-of-principle (POP) apparatus. The main goal of accelerators based on this concept is to use intense electron-beam heating and ablation of a hydrogen propellant stick to accelerate deuterium and/or tritium pellets to ultrahigh speeds (10 to 20 km/s) for plasma fueling of next-generation fusion devices such as the International Thermonuclear Engineering Reactor (ITER). The POP apparatus is described and initial results of pellet acceleration experiments are presented. Conceptual ultrahigh-speed pellet accelerators are discussed. 14 refs., 8 figs

  20. Comparison of measured with calculated dose distribution from a 120-MeV electron beam from a laser-plasma accelerator.

    Science.gov (United States)

    Lundh, O; Rechatin, C; Faure, J; Ben-Ismaïl, A; Lim, J; De Wagter, C; De Neve, W; Malka, V

    2012-06-01

    To evaluate the dose distribution of a 120-MeV laser-plasma accelerated electron beam which may be of potential interest for high-energy electron radiation therapy. In the interaction between an intense laser pulse and a helium gas jet, a well collimated electron beam with very high energy is produced. A secondary laser beam is used to optically control and to tune the electron beam energy and charge. The potential use of this beam for radiation treatment is evaluated experimentally by measurements of dose deposition in a polystyrene phantom. The results are compared to Monte Carlo simulations using the geant4 code. It has been shown that the laser-plasma accelerated electron beam can deliver a peak dose of more than 1 Gy at the entrance of the phantom in a single laser shot by direct irradiation, without the use of intermediate magnetic transport or focusing. The dose distribution is peaked on axis, with narrow lateral penumbra. Monte Carlo simulations of electron beam propagation and dose deposition indicate that the propagation of the intense electron beam (with large self-fields) can be described by standard models that exclude collective effects in the response of the material. The measurements show that the high-energy electron beams produced by an optically injected laser-plasma accelerator can deliver high enough dose at penetration depths of interest for electron beam radiotherapy of deep-seated tumors. Many engineering issues must be resolved before laser-accelerated electrons can be used for cancer therapy, but they also represent exciting challenges for future research. © 2012 American Association of Physicists in Medicine.

  1. High energy polarized electron beams

    International Nuclear Information System (INIS)

    Rossmanith, R.

    1987-01-01

    In nearly all high energy electron storage rings the effect of beam polarization by synchrotron radiation has been measured. The buildup time for polarization in storage rings is of the order of 10 6 to 10 7 revolutions; the spins must remain aligned over this time in order to avoid depolarization. Even extremely small spin deviations per revolution can add up and cause depolarization. The injection and the acceleration of polarized electrons in linacs is much easier. Although some improvements are still necessary, reliable polarized electron sources with sufficiently high intensity and polarization are available. With the linac-type machines SLC at Stanford and CEBAF in Virginia, experiments with polarized electrons will be possible

  2. Proceedings of the FNCA 2005 workshop on application of electron accelerator. EB treatment of wastewater

    International Nuclear Information System (INIS)

    Yoshii, Fumio; Kume, Tamikazu

    2006-08-01

    'Forum for Nuclear Cooperation in Asia (FNCA) Workshop on Application of Electron Accelerator' was sponsored by the Ministry of Education, Culture, Sports, Science and Technology (MEXT), Japan. The 2005 workshop was jointly organized by the Ministry of Science and Technology (MOST), Korea, Korea Atomic Energy Research Institute and Japan Atomic Energy Agency (JAEA). It was held at the International Nuclear Technology and Education Center (INTEC/KAERI), Daejeon, Korea from 14 to 18 November 2005. The Workshop was attended by 32 experts on application of electron accelerator from each of the participating countries, i.e., China (1), Indonesia (1), Korea (18), Malaysia (2), Philippines (1), Thailand (1) and Vietnam (1), and 7 participants from Japan. On the first day, a National Executive Management Seminar on Application of Electron Accelerator was held and attended by 45 participants. Total of 20 papers including Seminar lectures, invited papers on wastewater treatment by electron beam, and country reports on EB irradiation system were presented. The major areas of interest of FNCA member states for cooperation were identified for application of low energy electron accelerator to liquids (natural polymer, wastewater), solids (hydrogel, thin film) and gases (flue gas). Based on the evaluation and proposal from the participating countries, discussions were carried out to re-formulate the work plan of the project on natural polymers and wastewater for three years until FY 2008. It was agreed the FNCA 2006 workshop on EB crosslinking of natural polymers would be held in Malaysia. All manuscripts submitted by every speaker were included in the proceedings. The 18 presented papers are indexed individually. (J.P.N.)

  3. Energetic Electron Acceleration Observed by MMS in the Vicinity of an X-Line Crossing

    Science.gov (United States)

    Jaynes, A. N.; Turner, D. L.; Wilder, F. D.; Osmane, A.; Baker, D. N.; Blake, J. B.; Fennell, J. F.; Cohen, I. J.; Mauk, B. H.; Reeves, G. D.; hide

    2016-01-01

    During the first months of observations, the Magnetospheric Multiscale Fly's Eye Energetic Particle Spectrometer instrument has observed several instances of electron acceleration up to greater than 100 keV while in the vicinity of the dayside reconnection region. While particle acceleration associated with magnetic reconnection has been seen to occur up to these energies in the tail region, it had not yet been reported at the magnetopause. This study reports on observations of electron acceleration up to hundreds of keV that were recorded on 19 September 2015 around 1000 UT, in the midst of an X-line crossing. In the region surrounding the X-line, whistler-mode and broadband electrostatic waves were observed simultaneously with the appearance of highly energetic electrons which exhibited significant energization in the perpendicular direction. The mechanisms by which particles may be accelerated via reconnection-related processes are intrinsic to understanding particle dynamics among a wide range of spatial scales and plasma environments.

  4. Beam energy reduction in an acceleration gap

    International Nuclear Information System (INIS)

    Rhee, M.J.

    1990-01-01

    The subject of high-current accelerators has recently attracted considerable attention. The high-current beam accompanies a substantial amount of field energy in the space between the beam and the drift tube wall, as it propagates through a conducting drift tube of accelerator system. While such a beam is being accelerated in a gap, this field energy is subject to leak through the opening of the gap. The amount of energy lost in the gap is replenished by the beam at the expense of its kinetic energy. In this paper, the authors present a simple analysis of field energy loss in an acceleration gap for a relativistic beam for which beam particle velocity equals to c. It is found that the energy loss, which in turn reduces the beam kinetic energy, is ΔV = IZ 0 : the beam current times the characteristic impedance of the acceleration gap. As a result, the apparent acceleration voltage of the gap is reduced from the applied voltage by ΔV. This effect, especially for generation of high-current beam accelerated by a multigap accelerator, appears to be an important design consideration. The energy reduction mechanism and a few examples are presented

  5. Charged particle measurements from a rocket-borne electron accelerator experiment

    International Nuclear Information System (INIS)

    Duprat, G.R.J.; McNamara, A.G.; Whalen, B.A.

    1982-01-01

    This chapter presents charged particle observations which relate to the spatial distribution of energetic (keV) charged particles surrounding the accelerator during gun firings, the energy distribution of energetic electrons produced in the plasma by the electron beam, and the dependence of these characteristics on the beam energy, current, and injection angle. The primary objective of the flight of the Nike Black Brant rocket (NUB-06) was to use an electron beam to probe the auroral field lines for electric fields parallel to the magnetic field. The secondary objectives were to study electron beam interactions in the ionosphere and spacecraft charging effects. It is demonstrated that during high current (greater than or equal to 10ma electron beam firings, an intense suprathermal as well as energetic electron population is created on flux tubes near the beam. Certain similarities exist between these measurements and corresponding ones made in the Houston vacuum tank suggesting that the same instability observed in the laboratory is occurring at high altitudes in the ionosphere

  6. Numerical Studies of Electron Acceleration Behind Self-Modulating Proton Beam in Plasma with a Density Gradient

    CERN Document Server

    Petrenko, A.; Sosedkin, A.

    2016-01-01

    Presently available high-energy proton beams in circular accelerators carry enough momentum to accelerate high-intensity electron and positron beams to the TeV energy scale over several hundred meters of the plasma with a density of about 1e15 1/cm^3. However, the plasma wavelength at this density is 100-1000 times shorter than the typical longitudinal size of the high-energy proton beam. Therefore the self-modulation instability (SMI) of a long (~10 cm) proton beam in the plasma should be used to create the train of micro-bunches which would then drive the plasma wake resonantly. Changing the plasma density profile offers a simple way to control the development of the SMI and the acceleration of particles during this process. We present simulations of the possible use of a plasma density gradient as a way to control the acceleration of the electron beam during the development of the SMI of a 400 GeV proton beam in a 10 m long plasma. This work is done in the context of the AWAKE project --- the proof-of-prin...

  7. Investigation of the Electron Acceleration by a High-Power Laser and a Density-Tapered Mixed-Gas Cell

    Science.gov (United States)

    Kim, Jinju; Phung, Vanessa L. J.; Kim, Minseok; Hur, Min-Sup; Suk, Hyyong

    2017-10-01

    Plasma-based accelerators can generate about 1000 times stronger acceleration field compared with RF-based conventional accelerators, which can be done by high power laser and plasma. There are many issues in this research and one of them is development of a good plasma source for higher electron beam energy. For this purpose, we are investigating a special type of plasma source, which is a density-tapered gas cell with a mixed-gas for easy injection. By this type of special gas cell, we expect higher electron beam energies with easy injection in the wakefield. In this poster, some experimental results for electron beam generation with the density-tapered mixed-gas cell are presented. In addition to the experimental results, CFD (Computational-Fluid-Dynamics) and PIC (Particle-In-Cell) simulation results are also presented for comparison studies.

  8. Few-cycle surface plasmon enhanced electron acceleration

    International Nuclear Information System (INIS)

    Racz, P.; Lenner, M.; Kroo, N.; Farkas, Gy.; Dombi, P.; Takao Fuji; Krausz, F.; Irvine, S.E.; Elezzabi, A.Y.

    2010-01-01

    Complete text of publication follows. It is possible to generate high-quality ultrafast electron beams with keV energy based on surface plasmon-enhanced electron acceleration. The beam generated this way can be also used to investigate ultrafast phenomena in the plasmon field. For the better understanding of the temporal behavior of these ultrafast surface processes we carried out time-resolved experiments with 5.5 fs laser pulses for the first time. In this experiment, we executed an autocorrelation measurement with an ultra-broadband interferometer. By generating surface plasmons at the output of the interferometer, we measured the plasmonic photocurrent as a function of the delay between the interferometer arms. Figure (a) shows a typical measured result, and figure (b) shows the fourth order calculated autocorrelation function of the 5.5 fs long laser pulse, corresponding to the fourth order nonlinearity of the electron emission process. According to the correspondence of these two curves, we can also state that the length of the generated surface plasmon pulse is only 2-3 optical cycles. As a further experiment, we executed spectrally resolved measurements of the electron beam at higher intensities. According to these results, it is possible to reach electron beams with keV energy in the few-cycle regime too. It was found that the field strength of the surface plasmons is x 7 to x 30 higher than that of the focused laser pulse.

  9. Very high pulse-energy accelerators

    International Nuclear Information System (INIS)

    Ramirez, J.J.

    1989-01-01

    The dominant trend in the development of pulsed power accelerator technology over the last decade has been towards higher power and shorter pulse widths. Limitations in high voltage, high current switch performance, and in power flow through vacuum insulator housings led to the development of highly modular designs. This modular approach requires precise synchronization of the various modules and efficient methods of combining the power from these modules to drive a common load. The need to drive very low impedance loads led to effective ways to combine these modules in parallel. The Particle Beam Fusion Accelerator I (PBFA I) and Saturn are representative of these designs. Hermes III represent a new approach towards the efficient generation of higher voltages. It is designed to drive a 22-MV, 730-kA, 40-ns electron beam diode and combines conventional, modular pulsed power technology with linear induction accelerator concepts. High-power induction accelerator cavities are combined with voltage addition along a MITL to generate the desired output. This design differs from a conventional linac in that the voltages are added by the MITL flow rather than by a drifting beam that gains kinetic energy at each stage. This design is a major extrapolation of previous state-of-the-art technology represented by the injector module of the Advanced Test Accelerator and has proven to be efficient and reliable. The design and performance of Hermes III are presented together with a discussion of the application of this technology to the light ion beam inertial confinement fusion program. 18 refs., 9 figs

  10. Proceedings of the FNCA 2004 workshop on application of electron accelerator. EB treatment of flue gases

    International Nuclear Information System (INIS)

    Yoshii, Fumio; Kume, Tamikazu

    2005-06-01

    'Forum for Nuclear Cooperation in Asia (FNCA) Workshop on Application of Electron Accelerator' was sponsored by the Ministry of Education, Culture, Sports, Science and Technology (MEXT). The 2004 workshop was jointly organized by China Atomic Energy Authority (CAEA), Institute of Modern Physics/Chinese Academy of Sciences(IMP-CAS) and Japan Atomic Energy Research Institute (JAERI). It was held at Prime Hotel, Beijing, China from 6 to 10 September 2004. The Workshop was attended by 28 experts on application of electron accelerator from each of the participating countries, i.e., China, Indonesia, Korea, Malaysia, The Philippines, Thailand and Vietnam, and 10 participants from Japan. On the first day, a National Executive Management Seminar on Application of Electron Accelerator was held and attended by 67 participants. Total of 20 papers including Seminar lectures, invited papers on flue gas treatment by electron beam, and country reports on EB irradiation system were presented. The major areas of interest of FNCA member states for cooperation were identified for application of low energy electron accelerator as liquid (natural polymer, wastewater), solid (hydrogel, thin film) and gases (flue gas). Based on the proposal from the participating countries, discussions were carried out to re-formulate the work plan of the project for three years until FY 2005. It was agreed the FNCA 2005 workshop on EB treatment of wastewater will be held in Korea. All manuscripts submitted by every speaker were included in the proceedings. The 20 of the presented papers are indexed individually. (J.P.N.)

  11. Laser-Driven Very High Energy Electron/Photon Beam Radiation Therapy in Conjunction with a Robotic System

    Directory of Open Access Journals (Sweden)

    Kazuhisa Nakajima

    2014-12-01

    Full Text Available We present a new external-beam radiation therapy system using very-high-energy (VHE electron/photon beams generated by a centimeter-scale laser plasma accelerator built in a robotic system. Most types of external-beam radiation therapy are delivered using a machine called a medical linear accelerator driven by radio frequency (RF power amplifiers, producing electron beams with an energy range of 6–20 MeV, in conjunction with modern radiation therapy technologies for effective shaping of three-dimensional dose distributions and spatially accurate dose delivery with imaging verification. However, the limited penetration depth and low quality of the transverse penumbra at such electron beams delivered from the present RF linear accelerators prevent the implementation of advanced modalities in current cancer treatments. These drawbacks can be overcome if the electron energy is increased to above 50 MeV. To overcome the disadvantages of the present RF-based medical accelerators, harnessing recent advancement of laser-driven plasma accelerators capable of producing 1-GeV electron beams in a 1-cm gas cell, we propose a new embodiment of the external-beam radiation therapy robotic system delivering very high-energy electron/photon beams with an energy of 50–250 MeV; it is more compact, less expensive, and has a simpler operation and higher performance in comparison with the current radiation therapy system.

  12. Energetics of small electron acceleration episodes in the solar corona from radio noise storm observations

    Science.gov (United States)

    James, Tomin; Subramanian, Prasad

    2018-05-01

    Observations of radio noise storms can act as sensitive probes of nonthermal electrons produced in small acceleration events in the solar corona. We use data from noise storm episodes observed jointly by the Giant Metrewave Radio Telescope (GMRT) and the Nancay Radioheliograph (NRH) to study characteristics of the nonthermal electrons involved in the emission. We find that the electrons carry 1021 to 1024 erg/s, and that the energy contained in the electrons producing a representative noise storm burst ranges from 1020 to 1023 ergs. These results are a direct probe of the energetics involved in ubiquitous, small-scale electron acceleration episodes in the corona, and could be relevant to a nanoflare-like scenario for coronal heating.

  13. Conceptual design of a laser-plasma accelerator driven free-electron laser demonstration experiment

    Energy Technology Data Exchange (ETDEWEB)

    Seggebrock, Thorben

    2015-07-08

    Up to now, short-wavelength free-electron lasers (FEL) have been systems on the scale of hundreds of meters up to multiple kilometers. Due to the advancements in laser-plasma acceleration in the recent years, these accelerators have become a promising candidate for driving a fifth-generation synchrotron light source - a lab-scale free-electron laser. So far, demonstration experiments have been hindered by the broad energy spread typical for this type of accelerator. This thesis addresses the most important challenges of the conceptual design for a first lab-scale FEL demonstration experiment using analytical considerations as well as simulations. The broad energy spread reduces the FEL performance directly by weakening the microbunching and indirectly via chromatic emittance growth, caused by the focusing system. Both issues can be mitigated by decompressing the electron bunch in a magnetic chicane, resulting in a sorting by energies. This reduces the local energy spread as well as the local chromatic emittance growth and also lowers performance degradations caused by the short bunch length. Moreover, the energy dependent focus position leads to a focus motion within the bunch, which can be synchronized with the radiation pulse, maximizing the current density in the interaction region. This concept is termed chromatic focus matching. A comparison shows the advantages of the longitudinal decompression concept compared to the alternative approach of transverse dispersion. When using typical laser-plasma based electron bunches, coherent synchrotron radiation and space-charge contribute in equal measure to the emittance growth during decompression. It is shown that a chicane for this purpose must not be as weak and long as affordable to reduce coherent synchrotron radiation, but that an intermediate length is required. Furthermore, the interplay of the individual concepts and components is assessed in a start-to-end simulation, confirming the feasibility of the

  14. Conceptual design of a laser-plasma accelerator driven free-electron laser demonstration experiment

    International Nuclear Information System (INIS)

    Seggebrock, Thorben

    2015-01-01

    Up to now, short-wavelength free-electron lasers (FEL) have been systems on the scale of hundreds of meters up to multiple kilometers. Due to the advancements in laser-plasma acceleration in the recent years, these accelerators have become a promising candidate for driving a fifth-generation synchrotron light source - a lab-scale free-electron laser. So far, demonstration experiments have been hindered by the broad energy spread typical for this type of accelerator. This thesis addresses the most important challenges of the conceptual design for a first lab-scale FEL demonstration experiment using analytical considerations as well as simulations. The broad energy spread reduces the FEL performance directly by weakening the microbunching and indirectly via chromatic emittance growth, caused by the focusing system. Both issues can be mitigated by decompressing the electron bunch in a magnetic chicane, resulting in a sorting by energies. This reduces the local energy spread as well as the local chromatic emittance growth and also lowers performance degradations caused by the short bunch length. Moreover, the energy dependent focus position leads to a focus motion within the bunch, which can be synchronized with the radiation pulse, maximizing the current density in the interaction region. This concept is termed chromatic focus matching. A comparison shows the advantages of the longitudinal decompression concept compared to the alternative approach of transverse dispersion. When using typical laser-plasma based electron bunches, coherent synchrotron radiation and space-charge contribute in equal measure to the emittance growth during decompression. It is shown that a chicane for this purpose must not be as weak and long as affordable to reduce coherent synchrotron radiation, but that an intermediate length is required. Furthermore, the interplay of the individual concepts and components is assessed in a start-to-end simulation, confirming the feasibility of the

  15. Report of the Panel on Electron Accelerator Facilities, DOE/NSF Nuclear Science Advisory Committee

    International Nuclear Information System (INIS)

    1983-04-01

    This Panel finds that the highest priority for new accelerator construction in the US nuclear physics program is for an electron accelerator of high duty factor capable of producing beams at any energy in the range from 500 to 4000 MeV. After detailed study and consideration of the proposals for such facilities submitted to it, the Panel recommends: that the proposal submitted by the Southeastern University Research Association (SURA) be accepted and funded for the construction of a new National Electron Accelerator Laboratory (NEAL) centering on a 4 GeV linear accelerator-stretcher ring system capable of delivering intense, high duty factor, electron beams in the energy range from 500 to 4000 MeV. Additional recommendations relating to this principal one are to be found in the body of this report. As modified by the Panel consequent to its own studies and analyses, the estimated cost (in 1983 dollars) of the accelerator complex is 111.8 million dollars; of the entire laboratory is 146.8 million dollars; and the operating cost averaged over the first five years of operation is 18.1 million dollars per year. The projected 15 year total cost of the project is 418.3 million dollars. The construction period is estimated to be 4.5 years. The NEAL Laboratory, from the outset will be constructed and managed as a national rather than a regional facility and will provide the United States with a truly unique facility for research in electromagnetic physics

  16. Study of electron groupings in the Saclay linear accelerator; Etude du groupement des electrons dans l'accelerateur lineaire de Saclay

    Energy Technology Data Exchange (ETDEWEB)

    Bergere, R; Veyssiere, A; Beil, H [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1965-07-01

    The classical theory of the linear accelerator buncher does not fit the experimental measurements of the shape of the bunch of electrons performed at Saclay by the method of the energy spectrum. If the spurious effect of the mode converter at the input of the linac is taken into account the theory can fit the experimental results and also explain the variations of the phase of the bunch on the accelerating sine wave. (authors) [French] Une etude classique du groupeur en tete de l'Accelerateur Lineaire de Saclav conduit a des resultats incompatibles avec les resultats experimentaux obtenus sur le groupement des electrons par l'etude du spectre des frequences rayonnees par le faisceau d'electrons ou par l'etude des spectres en energie. Par contre si l'effet parasite du convertisseur de mode a l'entree de l'accelerateur est pris en consideration les resultats theoriques coincident bien avec les resultats experimentaux et permettent en outre d'expliquer les variations du calage en phase des paquets elementaires d'electrons. (auteurs)

  17. Applications and technology of electron beam accelerators

    International Nuclear Information System (INIS)

    Sethi, R.C.

    2005-01-01

    Traditionally, accelerators have been employed for pursuing research in basic sciences. But over the last couple of decades their uses have proliferated into the applied fields as well. The major credit for which goes to the electron beams. Electron beams or the radiations generated by them are being extensively used in almost all the applied areas. This article is a brief account of the impact made by the accelerator based electron beams and the attempts initiated by DAE for building a base in this technology. (author)

  18. The low-energy electron accelerator LEA for pilot scale operations

    International Nuclear Information System (INIS)

    Mehnert, R.; Klenert, P.

    1990-01-01

    An electron processor equipped with a linear cathode has been developed for use in pilot scale radiation processing. It can provide electron beam powers up to 6 kW at energies between 150 and 200 keV. The design of some components of the processor system and first results of its operation as part of a pilot unit for curing of furniture elements will be discussed. (author)

  19. On the properties of synchrotron-like X-ray emission from laser wakefield accelerated electron beams

    Science.gov (United States)

    McGuffey, C.; Schumaker, W.; Matsuoka, T.; Chvykov, V.; Dollar, F.; Kalintchenko, G.; Kneip, S.; Najmudin, Z.; Mangles, S. P. D.; Vargas, M.; Yanovsky, V.; Maksimchuk, A.; Thomas, A. G. R.; Krushelnick, K.

    2018-04-01

    The electric and magnetic fields responsible for electron acceleration in a Laser Wakefield Accelerator (LWFA) also cause electrons to radiate x-ray photons. Such x-ray pulses have several desirable properties including short duration and being well collimated with tunable high energy. We measure the scaling of this x-ray source experimentally up to laser powers greater than 100 TW. An increase in laser power allows electron trapping at a lower density as well as with an increased trapped charge. These effects resulted in an x-ray fluence that was measured to increase non-linearly with laser power. The fluence of x-rays was also compared with that produced from K-α emission resulting from a solid target interaction for the same energy laser pulse. The flux was shown to be comparable, but the LWFA x-rays had a significantly smaller source size. This indicates that such a source may be useful as a backlighter for probing high energy density plasmas with ultrafast temporal resolution.

  20. Proceedings of the FNCA 2003 workshop on application of electron accelerator. Radiation system for thin film

    International Nuclear Information System (INIS)

    Yoshii, Fumio; Kume, Tamikazu

    2004-06-01

    'Forum for Nuclear Cooperation in Asia (FNCA) Workshop on Application of Electron Accelerator' was sponsored by the Ministry of Education, Culture, Sports, Science and Technology (MEXT) and co-hosted by Malaysian Institute for Nuclear Technology Research (MINT) and Japan Atomic Energy Research Institute (JAERI). It was held at the Legend Hotel, Kuala Lumpur, Malaysia from 18 to 22 August 2003. The Workshop was attended by 28 experts on application of electron accelerator from each of the participating countries, i.e., China, Indonesia, Korea, Malaysia, The Philippines, Thailand and Vietnam, and 5 participants from Japan. On the first day, a National Executive Management Seminar on Application of Electron Accelerator was held and attended by 87 participants. Total of 19 papers including Seminar lectures, invited papers on film treatment by electron beam, and country reports on EB irradiation system were presented. The major areas of interest of FNCA member states for cooperation were identified for application of low energy electron accelerator as liquid, thin film and granules. The flue gas and wastewater treatments were added to the above major areas. Based on the proposal from the participating countries, discussions were carried out to re-formulate the work plan of the project for three years until FY 2004. All manuscripts submitted by every speaker were included in the proceedings. The 19 of the presented papers are indexed individually. (J.P.N.)

  1. Secondary Electron Emission Yields from PEP-II Accelerator Materials

    International Nuclear Information System (INIS)

    Kirby, Robert E.

    2000-01-01

    The PEP-II B-Factory at SLAC operates with aluminum alloy and copper vacuum chambers, having design positron and electron beam currents of 2 and 1 A, respectively. Titanium nitride coating of the aluminum vacuum chamber in the arcs of the positron ring is needed in order to reduce undesirable electron-cloud effects. The total secondary electron emission yield of TiN-coated aluminum alloy has been measured after samples of beam chamber material were exposed to air and again after electron-beam bombardment, as a function of incident electron beam angle and energy. The results may be used to simulate and better understand electron-cloud effects under actual operating conditions. We also present yield measurements for other accelerator materials because new surface effects are expected to arise as beam currents increase. Copper, in particular, is growing in popularity for its good thermal conductivity and self-radiation-shielding properties. The effect of electron bombardment, ''conditioning'', on the yield of TiN and copper is shown

  2. Electron guns for accelerators

    International Nuclear Information System (INIS)

    Rangarajan, L.M.; Mahadevan, S.; Ramamurthi, S.S.

    1995-01-01

    The high voltage, high current electron guns developed elsewhere for Linacs are based on cathode pulsing with direct emitting cathodes. Our grid pulsed triode gun employs indirect emitting cathode pellet under electron bombardment or a direct cathode emitter. Electron beam from the gun is injected to the accelerator guide at 40 kV and pulse duration is 2.8μsec. The gun is limited to axially symmetric geometry and electron optical design is optimized by computer programming. The gun with a water cooled Faraday cup is connected to a vacuum system comprising of a sputter ion pump and sorption pump. Working pressure is 1x10 -6 Pa. Gun is designed to be baked as an assembly at temperatures of 400 degC while vacuum processing. Materials are therefore restricted to refractory metals, SS, OFHC copper and all the electrodes are housed inside a ceramic tube. Lower Z graphite is used as a base material of Faraday cup. Grid is non-intercepting modulator anode, a new feature introduced, as compared to meshed grid system by others. CAT gun delivers 160 mA current pulses at 40 kV and its working characteristics such as perveance, emittance and beam radius compare well with SLAC and Hermosa guns. The above guns can be used for electron beam machines such as medical Linacs, industrial accelerators and EB welding equipment. (author). 2 refs., 2 figs

  3. A bremsstrahlung gamma-ray source based on stable ionization injection of electrons into a laser wakefield accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Döpp, A., E-mail: andreas.doepp@polytechnique.edu [LOA, ENSTA ParisTech, CNRS, École polytechnique, Université Paris-Saclay, 828 bd des Maréchaux, 91762 Palaiseau Cedex (France); Centro de Laseres Pulsados, Parque Cientfico, 37185 Villamayor, Salamanca (Spain); Guillaume, E.; Thaury, C.; Lifschitz, A. [LOA, ENSTA ParisTech, CNRS, École polytechnique, Université Paris-Saclay, 828 bd des Maréchaux, 91762 Palaiseau Cedex (France); Sylla, F. [SourceLAB SAS, 86 rue de Paris, 91400 Orsay (France); Goddet, J-P.; Tafzi, A.; Iaquanello, G.; Lefrou, T.; Rousseau, P. [LOA, ENSTA ParisTech, CNRS, École polytechnique, Université Paris-Saclay, 828 bd des Maréchaux, 91762 Palaiseau Cedex (France); Conejero, E.; Ruiz, C. [Departamento de Física Aplicada, Universidad de Salamanca, Plaza de laMerced s/n, 37008 Salamanca (Spain); Ta Phuoc, K.; Malka, V. [LOA, ENSTA ParisTech, CNRS, École polytechnique, Université Paris-Saclay, 828 bd des Maréchaux, 91762 Palaiseau Cedex (France)

    2016-09-11

    Laser wakefield acceleration permits the generation of ultra-short, high-brightness relativistic electron beams on a millimeter scale. While those features are of interest for many applications, the source remains constraint by the poor stability of the electron injection process. Here we present results on injection and acceleration of electrons in pure nitrogen and argon. We observe stable, continuous ionization-induced injection of electrons into the wakefield for laser powers exceeding a threshold of 7 TW. The beam charge scales approximately with the laser energy and is limited by beam loading. For 40 TW laser pulses we measure a maximum charge of almost 1 nC per shot, originating mostly from electrons of less than 10 MeV energy. The relatively low energy, the high charge and its stability make this source well-suited for applications such as non-destructive testing. Hence, we demonstrate the production of energetic radiation via bremsstrahlung conversion at 1 Hz repetition rate. In accordance with GEANT4 Monte-Carlo simulations, we measure a γ-ray source size of less than 100 μm for a 0.5 mm tantalum converter placed at 2 mm from the accelerator exit. Furthermore we present radiographs of image quality indicators.

  4. KEK (High Energy Accelerator Research Organization) annual report, 2005

    International Nuclear Information System (INIS)

    2006-01-01

    This report summarizes research activities of KEK (High Energy Accelerator Research Organization) in the fiscal year 2005. Two years have passed since the KEK was reorganized as an inter-university research institute corporation, and KEK continue to facilitate a wide range of research programs based on high-energy accelerators for users from universities. KEK consists of two research institutes, the Institute of Particle and Nuclear Studies (IPNS) and the Institute of Materials Science (IMSS); and two laboratories, the Accelerator Laboratory and the Applied Research Laboratory. KEK has been operating four major accelerator facilities in Tsukuba: the 12 GeV Proton Synchrotron (PS), the KEK B-factory (KEKB), the Photon Factory (PF), and the Electron/Positron Injector Linac. We are now engaged in the construction of the Japan Proton Accelerator Research Complex (J-PARC) in Tokai in cooperation with the Japan Atomic Energy Agency (JAEA). The J-PARC Center was established in February 2006 to take full responsibility for the operation of J-PARC. With the progress of construction, the PS ceased operation at the end of March 2006 after a history of 26 years. The task of KEK is to play a key role in the fields of elementary particle, nuclei, materials and life science as one of leading research facilities of the world. The fiscal year 2005 activities of both KEK employees and visiting researchers yielded excellent outcomes in these research fields. (J.P.N.)

  5. Plasma Density Tapering for Laser Wakefield Acceleration of Electrons and Protons

    International Nuclear Information System (INIS)

    Ting, A.; Gordon, D.; Kaganovich, D.; Sprangle, P.; Helle, M.; Hafizi, B.

    2010-01-01

    Extended acceleration in a Laser Wakefield Accelerator can be achieved by tailoring the phase velocity of the accelerating plasma wave, either through profiling of the density of the plasma or direct manipulation of the phase velocity. Laser wakefield acceleration has also reached a maturity that proton acceleration by wakefield could be entertained provided we begin with protons that are substantially relativistic, ∼1 GeV. Several plasma density tapering schemes are discussed. The first scheme is called ''bucket jumping'' where the plasma density is abruptly returned to the original density after a conventional tapering to move the accelerating particles to a neighboring wakefield period (bucket). The second scheme is designed to specifically accelerate low energy protons by generating a nonlinear wakefield in a plasma region with close to critical density. The third scheme creates a periodic variation in the phase velocity by beating two intense laser beams with laser frequency difference equal to the plasma frequency. Discussions and case examples with simulations are presented where substantial acceleration of electrons or protons could be obtained.

  6. Generation of X-rays by electrons recycling through thin internal targets of cyclic accelerators

    Science.gov (United States)

    Kaplin, V.; Kuznetsov, S.; Uglov, S.

    2018-05-01

    The use of thin (recycling effect) of electrons through them. The multiplicity of electron passes (M) is determined by the electron energy, accelerator parameters, the thickness, structure and material of a target and leads to an increase in the effective target thickness and the efficiency of radiation generation. The increase of M leads to the increase in the emittance of electron beams which can change the characteristics of radiation processes. The experimental results obtained using the Tomsk synchrotron and betatron showed the possibility of increasing the yield and brightness of coherent X-rays generated by the electrons passing (recycling) through thin crystals and periodic multilayers placed into the chambers of accelerators, when the recycling effect did not influence on the spectral and angular characteristics of generated X-rays.

  7. Development of an Automatic Frequency Control (AFC) System for RF Electron Linear Accelerators

    International Nuclear Information System (INIS)

    Cha, Sungsu; Kim, Yujong; Lee, Byeong-No; Joo, Youngwoo; Lee, Soo Min; Lee, Byung Cheol; Cha, Hyungki; Park, Hyung Dal; Lee, Seung Hyun

    2015-01-01

    In this paper, the design, fabrication, and RF power test of the AFC system for the X-band linac are presented. The main function of the AFC system is automatically matching of the resonance frequency of the accelerating structure and the RF frequency of the magnetron. For the frequency tuning, a fine tuning of 10 kHz is possible by rotating the tuning shaft with a rotation of 0.72 degree per pulse. Therefore, the frequency deviation is about 0.01%, and almost full RF power (2.1 MW) transmission was obtained because the reflected power is minimized. The Radiation Equipment Research Division of the Korea Atomic Energy Research Institute has been developing and upgrading a medical/industrial X-band RF electron linear accelerators. The medical compact RF electron linear accelerator consists of an electron gun, an acceleration tube (accelerating structure), two solenoid magnets, two steering magnets, a magnetron, modulator, an automatic frequency control (AFC) system, and an X-ray generating target. The accelerating structure of the component is composed of oxygen-free high-conductivity copper (OFHC). Therefore, the volume of the structure, hence, its resonance frequency can easily be changeable if the ambient temperature and pressure are changed. If the RF frequency of the 9300 MHz magnetron and the resonance frequency of accelerating structure are not matched, performance of the structure can be degraded. An AFC system is automatically matched with the RF frequency of the magnetron and resonance frequency of the accelerating structure, which obtained a high output power and reliable accelerator operation

  8. Development of an Automatic Frequency Control (AFC) System for RF Electron Linear Accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Cha, Sungsu; Kim, Yujong; Lee, Byeong-No; Joo, Youngwoo; Lee, Soo Min; Lee, Byung Cheol; Cha, Hyungki [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Park, Hyung Dal [Radiation Technology eXcellence, Daejeon (Korea, Republic of); Lee, Seung Hyun [Sungkyunkwan University, Suwon (Korea, Republic of)

    2015-10-15

    In this paper, the design, fabrication, and RF power test of the AFC system for the X-band linac are presented. The main function of the AFC system is automatically matching of the resonance frequency of the accelerating structure and the RF frequency of the magnetron. For the frequency tuning, a fine tuning of 10 kHz is possible by rotating the tuning shaft with a rotation of 0.72 degree per pulse. Therefore, the frequency deviation is about 0.01%, and almost full RF power (2.1 MW) transmission was obtained because the reflected power is minimized. The Radiation Equipment Research Division of the Korea Atomic Energy Research Institute has been developing and upgrading a medical/industrial X-band RF electron linear accelerators. The medical compact RF electron linear accelerator consists of an electron gun, an acceleration tube (accelerating structure), two solenoid magnets, two steering magnets, a magnetron, modulator, an automatic frequency control (AFC) system, and an X-ray generating target. The accelerating structure of the component is composed of oxygen-free high-conductivity copper (OFHC). Therefore, the volume of the structure, hence, its resonance frequency can easily be changeable if the ambient temperature and pressure are changed. If the RF frequency of the 9300 MHz magnetron and the resonance frequency of accelerating structure are not matched, performance of the structure can be degraded. An AFC system is automatically matched with the RF frequency of the magnetron and resonance frequency of the accelerating structure, which obtained a high output power and reliable accelerator operation.

  9. Dosimetric implications of shifts in linear accelerator electron beam energy detected in routine constancy checks: a scanning film densitometry detection method

    International Nuclear Information System (INIS)

    Cross, P.; Wang, Y.

    1993-01-01

    The effects of change in electron beam energy are primarily manifest by changes in the range parameters of the depth ionisation/dose curve. Even for a change of up to 10% in the mean energy at the surface, E O , the dose to the depth of maximum on the central axis changes by less than 1%. Using as a limit of acceptability that the change in the therapeutic range (R 85 ) should not be more than ±1.5 mm, the precision required by beam energy checking is that a change of 0.4 MeV in E O should be detectable for all electron beams provided by the accelerator. To satisfy this criterion a routine method is proposed that uses therapy verification film exposed to the electron beam under a perspex wedge. The automatically processed film is then scanned with the densitometer of a beam data acquisition system (BDAS). The optical density versus distance plot is analysed using the BDAS computer that converts it to a quasi-depth dose curve and then calculates E O and E p,0 from the range parameters. The results for electron beams from console energies of 5 to 14 MeV show that the test criterion is within the capability of the method, and that the method is very practical for routine use in a quality assurance program. 9 refs., 5 tab., 2 figs

  10. A real-time low energy electron calorimeter

    International Nuclear Information System (INIS)

    Mod Ali, N.; Smith, F.A.

    1999-01-01

    A real-time low energy electron calorimeter with a thin film window has been designed and fabricated to facilitate a reliable method of dose assessment for electron beam energies down to 200 keV. The work was initiated by the Radiation Physics Group of Queen Mary and Westfield College in collaboration with the National Physical Laboratory (NPL), Teddington. Irradiations were performed on the low and medium electron energy electron accelerators at the Malaysian Institute for Nuclear Technology Research (MINT). Calorimeter response was initially tested using the on-line temperature measurements for a 500-keV electron beam. The system was later redesigned by incorporating a data-logger to use on the self-shielded 200-keV beam. In use, the final version of the calorimeter could start logging temperature a short time before the calorimeter passed under the beam and continue measurements throughout the irradiation. Data could be easily retrieved at the end of the exposure. (author)

  11. The applications of electron accelerator. Liquid, thin film and gases

    International Nuclear Information System (INIS)

    Khairul Zaman Hj Mohd Dahlan; Kamaruddin Hashim; Zulkafli Ghazali

    2004-01-01

    As indicated by the results of this study, low energy electron beam accelerator of 200 keV to 500 keV can be utilized to irradiate thin hydrogel film in the range of 60 to 500 μm thickness. However, the industrial applications of this technology will depend on its applications. For thin films, cosmetic use such as faced mask is possible. The production of sago hydrogel for cosmetic used is in the process of commercialization in Malaysia. As for electron beam treatment of industrial wastewater in particular the effluent from the textile industry is still at infancy. Further work is necessary in order to have a base line data before the commercialization is taken place. Malaysia has also embarked on the electron beam treatment of flue gases and has completed the semi-pilot scale study by using 1.0 MeV electron accelerator voltage and 400 cum flue gas generated from diesel generator. This study was conducted together with the TNB Research, the research institute belongs to the electrical power company in Malaysia. For technology transfer and commercialization, MINT is planned to promote this technology to Independent Power Producers (IPP) in Malaysia. (author)

  12. Single-stage plasma-based correlated energy spread compensation for ultrahigh 6D brightness electron beams

    Science.gov (United States)

    Manahan, G. G.; Habib, A. F.; Scherkl, P.; Delinikolas, P.; Beaton, A.; Knetsch, A.; Karger, O.; Wittig, G.; Heinemann, T.; Sheng, Z. M.; Cary, J. R.; Bruhwiler, D. L.; Rosenzweig, J. B.; Hidding, B.

    2017-06-01

    Plasma photocathode wakefield acceleration combines energy gains of tens of GeV m-1 with generation of ultralow emittance electron bunches, and opens a path towards 5D-brightness orders of magnitude larger than state-of-the-art. This holds great promise for compact accelerator building blocks and advanced light sources. However, an intrinsic by-product of the enormous electric field gradients inherent to plasma accelerators is substantial correlated energy spread--an obstacle for key applications such as free-electron-lasers. Here we show that by releasing an additional tailored escort electron beam at a later phase of the acceleration, when the witness bunch is relativistically stable, the plasma wave can be locally overloaded without compromising the witness bunch normalized emittance. This reverses the effective accelerating gradient, and counter-rotates the accumulated negative longitudinal phase space chirp of the witness bunch. Thereby, the energy spread is reduced by an order of magnitude, thus enabling the production of ultrahigh 6D-brightness beams.

  13. Quasi-phase-matched acceleration of electrons in a corrugated plasma channel

    Directory of Open Access Journals (Sweden)

    S. J. Yoon

    2012-08-01

    Full Text Available A laser pulse propagating in a corrugated plasma channel is composed of spatial harmonics whose phase velocities can be subluminal. The phase velocity of a spatial harmonic can be matched to the speed of a relativistic electron resulting in direct acceleration by the guided laser field in a plasma waveguide and linear energy gain over the interaction length. Here we examine the fully self-consistent interaction of the laser pulse and electron beam using particle-in-cell (PIC simulations. For low electron beam densities, we find that the ponderomotive force of the laser pulse pushes plasma channel electrons towards the propagation axis, which deflects the beam electrons. When the beam density is high, the space charge force of the beam drives the channel electrons off axis, providing collimation of the beam. In addition, we consider a ramped density profile for lowering the threshold energy for trapping in a subluminal spatial harmonic. By using a density ramp, the trapping energy for a normalized vector potential of a_{0}=0.1 is reduced from a relativistic factor γ_{0}=170 to γ_{0}=20.

  14. Two Step Acceleration Process of Electrons in the Outer Van Allen Radiation Belt by Time Domain Electric Field Bursts and Large Amplitude Chorus Waves

    Science.gov (United States)

    Agapitov, O. V.; Mozer, F.; Artemyev, A.; Krasnoselskikh, V.; Lejosne, S.

    2014-12-01

    A huge number of different non-linear structures (double layers, electron holes, non-linear whistlers, etc) have been observed by the electric field experiment on the Van Allen Probes in conjunction with relativistic electron acceleration in the Earth's outer radiation belt. These structures, found as short duration (~0.1 msec) quasi-periodic bursts of electric field in the high time resolution electric field waveform, have been called Time Domain Structures (TDS). They can quite effectively interact with radiation belt electrons. Due to the trapping of electrons into these non-linear structures, they are accelerated up to ~10 keV and their pitch angles are changed, especially for low energies (˜1 keV). Large amplitude electric field perturbations cause non-linear resonant trapping of electrons into the effective potential of the TDS and these electrons are then accelerated in the non-homogeneous magnetic field. These locally accelerated electrons create the "seed population" of several keV electrons that can be accelerated by coherent, large amplitude, upper band whistler waves to MeV energies in this two step acceleration process. All the elements of this chain acceleration mechanism have been observed by the Van Allen Probes.

  15. In-situ measurements of the secondary electron yield in an accelerator environment: Instrumentation and methods

    International Nuclear Information System (INIS)

    Hartung, W.H.; Asner, D.M.; Conway, J.V.; Dennett, C.A.; Greenwald, S.; Kim, J.-S.; Li, Y.; Moore, T.P.; Omanovic, V.; Palmer, M.A.; Strohman, C.R.

    2015-01-01

    The performance of a particle accelerator can be limited by the build-up of an electron cloud (EC) in the vacuum chamber. Secondary electron emission from the chamber walls can contribute to EC growth. An apparatus for in-situ measurements of the secondary electron yield (SEY) in the Cornell Electron Storage Ring (CESR) was developed in connection with EC studies for the CESR Test Accelerator program. The CESR in-situ system, in operation since 2010, allows for SEY measurements as a function of incident electron energy and angle on samples that are exposed to the accelerator environment, typically 5.3 GeV counter-rotating beams of electrons and positrons. The system was designed for periodic measurements to observe beam conditioning of the SEY with discrimination between exposure to direct photons from synchrotron radiation versus scattered photons and cloud electrons. The samples can be exchanged without venting the CESR vacuum chamber. Measurements have been done on metal surfaces and EC-mitigation coatings. The in-situ SEY apparatus and improvements to the measurement tools and techniques are described

  16. In-situ measurements of the secondary electron yield in an accelerator environment: Instrumentation and methods

    Energy Technology Data Exchange (ETDEWEB)

    Hartung, W.H., E-mail: wh29@cornell.edu; Asner, D.M.; Conway, J.V.; Dennett, C.A.; Greenwald, S.; Kim, J.-S.; Li, Y.; Moore, T.P.; Omanovic, V.; Palmer, M.A.; Strohman, C.R.

    2015-05-21

    The performance of a particle accelerator can be limited by the build-up of an electron cloud (EC) in the vacuum chamber. Secondary electron emission from the chamber walls can contribute to EC growth. An apparatus for in-situ measurements of the secondary electron yield (SEY) in the Cornell Electron Storage Ring (CESR) was developed in connection with EC studies for the CESR Test Accelerator program. The CESR in-situ system, in operation since 2010, allows for SEY measurements as a function of incident electron energy and angle on samples that are exposed to the accelerator environment, typically 5.3 GeV counter-rotating beams of electrons and positrons. The system was designed for periodic measurements to observe beam conditioning of the SEY with discrimination between exposure to direct photons from synchrotron radiation versus scattered photons and cloud electrons. The samples can be exchanged without venting the CESR vacuum chamber. Measurements have been done on metal surfaces and EC-mitigation coatings. The in-situ SEY apparatus and improvements to the measurement tools and techniques are described.

  17. Proposal to detect an emission of unusual super-high energy electrons in electron storage rings

    Directory of Open Access Journals (Sweden)

    Da-peng Qian

    2014-01-01

    Full Text Available According to an extended Lorentz–Einstein mass formula taken into the uncertainty principle, it is predicted that the electron beams passing accelerating electric field should with a small probability generate abnormal super-high energy electrons which are much higher than the beam energy. Author’s preliminary experiment result at electron storage ring has hinted these signs, so suggests to more strictly detect this unusual phenomenon, and thus to test the extended mass formula as well as a more perfect special relativity.

  18. Radiative damping in plasma-based accelerators

    Directory of Open Access Journals (Sweden)

    I. Yu. Kostyukov

    2012-11-01

    Full Text Available The electrons accelerated in a plasma-based accelerator undergo betatron oscillations and emit synchrotron radiation. The energy loss to synchrotron radiation may seriously affect electron acceleration. The electron dynamics under combined influence of the constant accelerating force and the classical radiation reaction force is studied. It is shown that electron acceleration cannot be limited by radiation reaction. If initially the accelerating force was stronger than the radiation reaction force, then the electron acceleration is unlimited. Otherwise the electron is decelerated by radiative damping up to a certain instant of time and then accelerated without limits. It is shown that regardless of the initial conditions the infinite-time asymptotic behavior of an electron is governed by a self-similar solution providing that the radiative damping becomes exactly equal to 2/3 of the accelerating force. The relative energy spread induced by the radiative damping decreases with time in the infinite-time limit. The multistage schemes operating in the asymptotic acceleration regime when electron dynamics is determined by the radiation reaction are discussed.

  19. Dosimetry of the energy of the electrons beam and virtual distance of the source of a lineal accelerator

    International Nuclear Information System (INIS)

    Gonzales, A.; Garcia, B.; Ramirez, J.; Marquina, J.

    2014-08-01

    The objectives of this work were to characterize, to gauge the energy of a electrons beam of 12 MeV and to find the virtual distance of the source for a lineal accelerator Trilogy-Varian. For the characterization, calibration and to find the virtual distance of the source of a lineal accelerator Trilogy-Varian, a water phantom was used (cylindrical Cuba 3-D) of Sun-Nuclear. The following values were found: R 50.ion = 4, 95 g/cm 2 , R 50 = 5, 04 g/cm 2 , Z ref = 2,92 g/cm 2 , Z max = 2, 60 g/cm 2 . In the calibration was found D W,Q (Z max ) = 1, 0015 c Gy/Um. In the profile In-plane was measured a symmetry and flatness of 1, 9% and 1, 6% respectively. In the profile Cross-plane a symmetry was measured and flatness of 1, 9% and 1, 3% respectively. The virtual distance regarding the source was of DFS (virtual) =105,81 cm. The electrons beam of 12 MeV was characterized and gauged satisfactorily, were carried out the In-plane and Cross-plane profiles, obtaining all the parameters inside the acceptance limit. The virtual distance of the source was of 105,81 cm. (Author)

  20. Ion acceleration in non-equilibrium plasmas driven by fast drifting electron

    Energy Technology Data Exchange (ETDEWEB)

    Castro, G. [INFN- Laboratori Nazionali del Sud, via S.Sofia 62, 95123 Catania (Italy); Università degli Studi di Catania, Dipartimento di Fisica e Astronomia, V. S.Sofia 64, 95123 Catania (Italy); Di Bartolo, F., E-mail: fdibartolo@unime.it [Università di Messina, V.le F. Stagno D’Alcontres 31, 98166, Messina (Italy); Gambino, N. [INFN- Laboratori Nazionali del Sud, via S.Sofia 62, 95123 Catania (Italy); Università degli Studi di Catania, Dipartimento di Metodologie Fisiche e Chimiche per L’ingegneria, Viale A.Doria 6, 95125 Catania (Italy); Mascali, D. [INFN- Laboratori Nazionali del Sud, via S.Sofia 62, 95123 Catania (Italy); CSFNSM, Viale A. Doria 6, 95125 Catania (Italy); Romano, F.P. [INFN- Laboratori Nazionali del Sud, via S.Sofia 62, 95123 Catania (Italy); CNR-IBAM Via Biblioteca 4, 95124 Catania (Italy); Anzalone, A.; Celona, L.; Gammino, S. [INFN- Laboratori Nazionali del Sud, via S.Sofia 62, 95123 Catania (Italy); Di Giugno, R. [INFN- Laboratori Nazionali del Sud, via S.Sofia 62, 95123 Catania (Italy); Università degli Studi di Catania, Dipartimento di Fisica e Astronomia, V. S.Sofia 64, 95123 Catania (Italy); Lanaia, D. [INFN- Laboratori Nazionali del Sud, via S.Sofia 62, 95123 Catania (Italy); Miracoli, R. [INFN- Laboratori Nazionali del Sud, via S.Sofia 62, 95123 Catania (Italy); Università degli Studi di Catania, Dipartimento di Fisica e Astronomia, V. S.Sofia 64, 95123 Catania (Italy); Serafino, T. [CSFNSM, Viale A. Doria 6, 95125 Catania (Italy); Tudisco, S. [INFN- Laboratori Nazionali del Sud, via S.Sofia 62, 95123 Catania (Italy); CSFNSM, Viale A. Doria 6, 95125 Catania (Italy)

    2013-05-01

    We hereby present results on ion acceleration mechanisms in non equilibrium plasmas generated by microwaves or high intensity laser pulses. Experiments point out that in magnetized plasmas X–B conversion takes place for under resonance values of the magnetic field, i.e. an electromagnetic mode is converted into an electrostatic wave. The strong self-generated electric field, of the order of 10{sup 7} V/m, causes a E × B drift which accelerates both ions and electrons, as it is evident by localized sputtering in the plasma chamber. These fields are similar (in magnitude) to the ones obtainable in laser generated plasmas at intensity of 10{sup 12} W/cm{sup 2}. In this latter case, we observe that the acceleration mechanism is driven by electrons drifting much faster than plasma bulk, thus generating an extremely strong electric field ∼10{sup 7} V/m. The two experiments confirm that ions acceleration at low energy is possible with table-top devices and following complementary techniques: i.e. by using microwave-driven (producing CW beams) plasmas, or non-equilibrium laser-driven plasmas (producing pulsed beams). Possible applications involve ion implantation, materials surface modifications, ion beam assisted lithography, etc.

  1. Time dependent formulation of the energy loss by an accelerated intense electron beam just emitted by the cathode of RF-FEL photoinjector

    Energy Technology Data Exchange (ETDEWEB)

    Salah, Wa' el [Physics Department, Hashemite University, Zarqa 13115 (Jordan)]. E-mail: wael_salahh@hotmail.com; Coacolo, J.-L. [Institut de Physique Nucleaire d' Orsay, 91406 Orsay Cedex (France); Hallak, A.B. [Physics Department, Hashemite University, Zarqa 13115 (Jordan); Al-Obaid, M. [Physics Department, Hashemite University, Zarqa 13115 (Jordan)

    2006-08-01

    The energy loss by an accelerated electron bunch of a conical shape propagating in the laser-driven RF-photoinjector is expressed in terms of an expansion of the vector and scalar potentials into a series of eigenfunctions of the empty unit 'pill-box' cavity. A versatile and simple analytical formula which can be easily applied to a bunch of any shape is obtained.

  2. New accelerators in high-energy physics

    International Nuclear Information System (INIS)

    Blewett, J.P.

    1982-01-01

    First, I should like to mention a few new ideas that have appeared during the last few years in the accelerator field. A couple are of importance in the design of injectors, usually linear accelerators, for high-energy machines. Then I shall review some of the somewhat sensational accelerator projects, now in operation, under construction or just being proposed. Finally, I propose to mention a few applications of high-energy accelerators in fields other than high-energy physics. I realize that this is a digression from my title but I hope that you will find it interesting

  3. Multiple quasi-monoenergetic electron beams from laser-wakefield acceleration with spatially structured laser pulse

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Y.; Li, M. H.; Li, Y. F.; Wang, J. G.; Tao, M. Z.; Han, Y. J.; Zhao, J. R.; Huang, K.; Yan, W. C.; Ma, J. L.; Li, Y. T. [Beijing National Laboratory of Condensed Matter Physics, Institute of Physics, CAS, Beijing 100080 (China); Chen, L. M., E-mail: lmchen@iphy.ac.cn [Beijing National Laboratory of Condensed Matter Physics, Institute of Physics, CAS, Beijing 100080 (China); Department of Physics and Astronomy and IFSA Collaborative Innovation Center, Shanghai Jiao Tong University, Shanghai 200240 (China); Li, D. Z. [Institute of High Energy Physics, CAS, Beijing 100049 (China); Chen, Z. Y. [Institute of Fluid Physics, China Academy of Engineering Physics, Mianyang, Sichuan 621999 (China); Sheng, Z. M. [Department of Physics and Astronomy and IFSA Collaborative Innovation Center, Shanghai Jiao Tong University, Shanghai 200240 (China); Department of Physics, Scottish Universities Physics Alliance, University of Strathclyde, Glasgow G4 0NG (United Kingdom); Zhang, J. [Department of Physics and Astronomy and IFSA Collaborative Innovation Center, Shanghai Jiao Tong University, Shanghai 200240 (China)

    2015-08-15

    By adjusting the focus geometry of a spatially structured laser pulse, single, double, and treble quasi-monoenergetic electron beams were generated, respectively, in laser-wakefield acceleration. Single electron beam was produced as focusing the laser pulse to a single spot. While focusing the laser pulse to two spots that are approximately equal in energy and size and intense enough to form their own filaments, two electron beams were produced. Moreover, with a proper distance between those two focal spots, three electron beams emerged with a certain probability owing to the superposition of the diffractions of those two spots. The energy spectra of the multiple electron beams are quasi-monoenergetic, which are different from that of the large energy spread beams produced due to the longitudinal multiple-injection in the single bubble.

  4. MeV electron acceleration at 1kHz with <10 mJ laser pulses

    Science.gov (United States)

    Salehi, Fatholah; Goers, Andy; Hine, George; Feder, Linus; Kuk, Donghoon; Kim, Ki-Yong; Milchberg, Howard

    2016-10-01

    We demonstrate laser driven acceleration of electrons at 1 kHz repetition rate with pC charge above 1MeV per shot using required for relativistic self-focusing low enough for mJ scale laser pulses to self- focus and drive strong wakefields. Experiments and particle-in-cell simulations show that optimal drive pulse duration and chirp for maximum electron bunch charge and energy depends on the target gas species. High repetition rate, high charge, and short duration electron bunches driven by very modest pulse energies constitutes an ideal portable electron source for applications such as ultrafast electron diffraction experiments and high rep. rate γ-ray production. This work is supported by the US Department of Energy, the National Science Foundation, and the Air Force Office of Scientific Research.

  5. Compact ILU-type electron accelerators as a base for industrial 4-sided irradiation systems for cable and tubes

    International Nuclear Information System (INIS)

    Auslender, V.L.; Nekhaev, V.E.; Panfilov, A.D.; Tuvik, A.A.

    1999-01-01

    The ILU-type industrial electron accelerators are developed in BINP sins 1967. Their energy range is 0.7-4.0 MeV at beam power of 20-50 kW. The comparison of the irradiation results after bilateral and four-sided irradiation of cables and tubes is given. It is shown that the required electron energy and beam power in the case of four-sided irradiation are sufficiently lower than in the case of bilateral irradiation, resulting in an increase of productive rate of the process and improvement of treatment quality. The installations for four-sided irradiation of cables and tubes are based on the industrial electron accelerators type ILU

  6. Radiation effects on semiconductor devices in high energy heavy ion accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Belousov, Anton

    2014-10-20

    Radiation effects on semiconductor devices in GSI Helmholtz Center for Heavy Ion Research are becoming more and more significant with the increase of beam intensity due to upgrades. Moreover a new accelerator is being constructed on the basis of GSI within the project of facility for antiproton and ion research (FAIR). Beam intensities will be increased by factor of 100 and energies by factor of 10. Radiation fields in the vicinity of beam lines will increase more than 2 orders of magnitude and so will the effects on semiconductor devices. It is necessary to carry out a study of radiation effects on semiconductor devices considering specific properties of radiation typical for high energy heavy ion accelerators. Radiation effects on electronics in accelerator environment may be divided into two categories: short-term temporary effects and long-term permanent degradation. Both may become critical for proper operation of some electronic devices. This study is focused on radiation damage to CCD cameras in radiation environment of heavy ion accelerator. Series of experiments with irradiation of devices under test (DUTs) by secondary particles produced during ion beam losses were done for this study. Monte Carlo calculations were performed to simulate the experiment conditions and conditions expected in future accelerator. Corresponding comparisons and conclusions were done. Another device typical for accelerator facilities - industrial Ethernet switch was tested in similar conditions during this study. Series of direct irradiations of CCD and MOS transistors with heavy ion beams were done as well. Typical energies of the primary ion beams were 0.5-1 GeV/u. Ion species: from Na to U. Intensities of the beam up to 10{sup 9} ions/spill with spill length of 200-300 ns. Criteria of reliability and lifetime of DUTs in specific radiation conditions were formulated, basing on experimental results of the study. Predictions of electronic device reliability and lifetime were

  7. FLARE VERSUS SHOCK ACCELERATION OF HIGH-ENERGY PROTONS IN SOLAR ENERGETIC PARTICLE EVENTS

    International Nuclear Information System (INIS)

    Cliver, E. W.

    2016-01-01

    Recent studies have presented evidence for a significant to dominant role for a flare-resident acceleration process for high-energy protons in large (“gradual”) solar energetic particle (SEP) events, contrary to the more generally held view that such protons are primarily accelerated at shock waves driven by coronal mass ejections (CMEs). The new support for this flare-centric view is provided by correlations between the sizes of X-ray and/or microwave bursts and associated SEP events. For one such study that considered >100 MeV proton events, we present evidence based on CME speeds and widths, shock associations, and electron-to-proton ratios that indicates that events omitted from that investigation’s analysis should have been included. Inclusion of these outlying events reverses the study’s qualitative result and supports shock acceleration of >100 MeV protons. Examination of the ratios of 0.5 MeV electron intensities to >100 MeV proton intensities for the Grechnev et al. event sample provides additional support for shock acceleration of high-energy protons. Simply scaling up a classic “impulsive” SEP event to produce a large >100 MeV proton event implies the existence of prompt 0.5 MeV electron events that are approximately two orders of magnitude larger than are observed. While classic “impulsive” SEP events attributed to flares have high electron-to-proton ratios (≳5 × 10 5 ) due to a near absence of >100 MeV protons, large poorly connected (≥W120) gradual SEP events, attributed to widespread shock acceleration, have electron-to-proton ratios of ∼2 × 10 3 , similar to those of comparably sized well-connected (W20–W90) SEP events.

  8. Cavity characterization for general use in linear electron accelerators

    International Nuclear Information System (INIS)

    Souza Neto, M.V. de.

    1985-01-01

    The main objective of this work is to is to develop measurement techniques for the characterization of microwave cavities used in linear electron accelerators. Methods are developed for the measurement of parameters that are essential to the design of an accelerator structure using conventional techniques of resonant cavities at low power. Disk-loaded cavities were designed and built, similar to those in most existing linear electron accelerators. As a result, the methods developed and the estimated accuracy were compared with those from other investigators. The results of this work are relevant for the design of cavities with the objective of developing linear electron accelerators. (author) [pt

  9. Diagnostics for induction accelerators

    International Nuclear Information System (INIS)

    Fessenden, T.J.

    1996-04-01

    The induction accelerator was conceived by N. C. Christofilos and first realized as the Astron accelerator that operated at LLNL from the early 1960's to the end of 1975. This accelerator generated electron beams at energies near 6 MeV with typical currents of 600 Amperes in 400 ns pulses. The Advanced Test Accelerator (ATA) built at Livermore's Site 300 produced 10,000 Ampere beams with pulse widths of 70 ns at energies approaching 50 MeV. Several other electron and ion induction accelerators have been fabricated at LLNL and LBNL. This paper reviews the principal diagnostics developed through efforts by scientists at both laboratories for measuring the current, position, energy, and emittance of beams generated by these high current, short pulse accelerators. Many of these diagnostics are closely related to those developed for other accelerators. However, the very fast and intense current pulses often require special diagnostic techniques and considerations. The physics and design of the more unique diagnostics developed for electron induction accelerators are presented and discussed in detail

  10. Beam-front dynamics and ion acceleration in drifting intense relativistic electron beams

    International Nuclear Information System (INIS)

    Alexander, K.F.; Hintze, W.

    1976-01-01

    Collective ion acceleration at the injection of a relativistic electron beam into a low-pressure gas or a plasma is discussed and its strong dependence on the beam-front dynamics is shown. A simple one-dimensional model taking explicitly into account the motion and ionizing action of the ions in the beam-front region is developed for the calculation of the beam drift velocity. The obtained pressure dependence is in good agreement with experimental data. The energy distribution is shown of the ions accelerated in the moving potential well of the space charge region. Scaling laws for the beam-front dynamics and ion acceleration are derived. (J.U.)

  11. High power millimeter-wave free electron laser based on recirculating electrostatic accelerator

    International Nuclear Information System (INIS)

    Lee, Byung-Cheol; Kim, Sun-Kook; Jeong, Young-Uk; Cho, Sung-Oh; Lee, Jongmin

    1995-01-01

    Progress in the development of a high power, millimeter-wave free electron laser driven by a recirculating electrostatic accelerator is reported. The energy and the current of electron beam are 430 keV and 2 A, respectively. The expected average output power is above 10 kW at the wavelength of 3-10 mm. Minimizing of the beam loss is a key issue for CW operation of the FEL with high efficiency. (author)

  12. Ion and electron Van de Graaff accelerators of Kyoto University

    International Nuclear Information System (INIS)

    Fukuzawa, F.; Imanishi, N.; Tomita, M.; Norisawa, K.; Yoshida, K.; Ohdaira, T.

    1990-01-01

    Two Van de Graaff accelerators are available at the Uji campus of Kyoto University. One is a 4MV machine, which is used for heavy ion acceleration, while the other is a 2MV machine for electron acceleration. These machines have been modified in various parts and currently used very actively in many fields of investigation. Important modifications of the 4MV machine are: use of a newly developed accelerating tube, addition of a charge-changer before the analyzing magnet, renewal of the charging belt, and development of a microbeam system for PIXE and RBS analysis. An attempt is now being made to accelerate micro-particles using the 2MV machine. The new accelerating tube has bucket type electrodes with large accelerating apertures. By charge-changing the accelerated 1+ ions to higher charge states, 2+, 3+, ..., at the entrance of the analyzing magnet, Ar ions with energies of up to 2.73, 6.21, .... MeV can be deflected to the duct. Scanning microbeam PIXE and RBS are powerful tools for analysis of spatial elemental distribution. Calculations suggest that a beam size of about 3 μm can be attained by using an object aperture of 10μm in diameter and controlling the beam divergence within 10μ rad in both directions. (N.K.)

  13. Design of an accelerator tube for 500 keV/10 mA electron beam machine

    International Nuclear Information System (INIS)

    Maksum, W.; Sudjatmoko; Suprapto

    1999-01-01

    A design of an accelerator tube for 500 keV/10 mA electron beam machine was carried out. This tube was used for focussing and accelerating of electron beams. The tube was designed to consist of some electrodes insulator tubes and a voltage divider. The electrodes was made of stainless steel due to its low outgassing constant and stainless, the insulator was made of pyrex glass due to its low outgassing constant and high temperature proof and the voltage divider was made of high-ohmic resistors used for accelerating potential distribution at the electrodes. The stainless steel electrodes were comic shaped 3 mm thick with 134 mm inlet diameter and 60 mm outlet diameter. The number for this electrodes was 34 so that the potential gap between adjacent electrodes not exceed 15 kV. The insulators were 5 mm thick, 150 mm outer diameter, 140 mm inner diameter and 32 mm long. The insulators were joined to the electrodes by using an epoxy form an accelerator tube. The designed accelerator tube could be constructed and operated at a vacuum of 10 -6 torr and accelerated electron beam at an energy of 500 keV. (author)

  14. Beam dynamics study of a 30 MeV electron linear accelerator to drive a neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Sandeep; Yang, Haeryong; Kang, Heung-Sik, E-mail: hskang@postech.ac.kr [Pohang Accelerator Laboratory, San31, Hyoja-dong, Pohang, Gyeongbuk 790-784 (Korea, Republic of)

    2014-02-14

    An experimental neutron facility based on 32 MeV/18.47 kW electron linac has been studied by means of PARMELA simulation code. Beam dynamics study for a traveling wave constant gradient electron accelerator is carried out to reach the preferential operation parameters (E = 30 MeV, P = 18 kW, dE/E < 12.47% for 99% particles). The whole linac comprises mainly E-gun, pre-buncher, buncher, and 2 accelerating columns. A disk-loaded, on-axis-coupled, 2π/3-mode type accelerating rf cavity is considered for this linac. After numerous optimizations of linac parameters, 32 MeV beam energy is obtained at the end of the linac. As high electron energy is required to produce acceptable neutron flux. The final neutron flux is estimated to be 5 × 10{sup 11} n/cm{sup 2}/s/mA. Future development will be the real design of a 30 MeV electron linac based on S band traveling wave.

  15. An MCNP-based model for the evaluation of the photoneutron dose in high energy medical electron accelerators.

    Science.gov (United States)

    Carinou, Eleutheria; Stamatelatos, Ion Evangelos; Kamenopoulou, Vassiliki; Georgolopoulou, Paraskevi; Sandilos, Panayotis

    The development of a computational model for the treatment head of a medical electron accelerator (Elekta/Philips SL-18) by the Monte Carlo code mcnp-4C2 is discussed. The model includes the major components of the accelerator head and a pmma phantom representing the patient body. Calculations were performed for a 14 MeV electron beam impinging on the accelerator target and a 10 cmx10 cm beam area at the isocentre. The model was used in order to predict the neutron ambient dose equivalent at the isocentre level and moreover the neutron absorbed dose distribution within the phantom. Calculations were validated against experimental measurements performed by gold foil activation detectors. The results of this study indicated that the equivalent dose at tissues or organs adjacent to the treatment field due to photoneutrons could be up to 10% of the total peripheral dose, for the specific accelerator characteristics examined. Therefore, photoneutrons should be taken into account when accurate dose calculations are required to sensitive tissues that are adjacent to the therapeutic X-ray beam. The method described can be extended to other accelerators and collimation configurations as well, upon specification of treatment head component dimensions, composition and nominal accelerating potential.

  16. Program for Plasma-Based Concepts for Future High Energy Accelerators

    International Nuclear Information System (INIS)

    Katsouleas, Thomas C.; Muggli, Patric

    2003-01-01

    OAK B204 Program for Plasma-Based Concepts for Future High Energy Accelerators. The progress made under this program in the period since November 15, 2002 is reflected in this report. The main activities for this period were to conduct the first run of the E-164 high-gradient wakefield experiment at SLAC, to prepare for run 2 and to continue our collaborative effort with CERN to model electron cloud interactions in circular accelerators. Each of these is described. Also attached to this report are papers that were prepared or appeared during this period

  17. Energy Spread Reduction of Electron Beams Produced via Laser Wake

    Energy Technology Data Exchange (ETDEWEB)

    Pollock, Bradley Bolt [Univ. of California, San Diego, CA (United States)

    2012-01-01

    Laser wakefield acceleration of electrons holds great promise for producing ultra-compact stages of GeV scale, high quality electron beams for applications such as x-ray free electron lasers and high energy colliders. Ultra-high intensity laser pulses can be self-guided by relativistic plasma waves over tens of vacuum diffraction lengths, to give >1 GeV energy in cm-scale low density plasma using ionization-induced injection to inject charge into the wake at low densities. This thesis describes a series of experiments which investigates the physics of LWFA in the self-guided blowout regime. Beginning with high density gas jet experiments the scaling of the LWFA-produced electron beam energy with plasma electron density is found to be in excellent agreement with both phenomenological theory and with 3-D PIC simulations. It is also determined that self-trapping of background electrons into the wake exhibits a threshold as a function of the electron density, and at the densities required to produce electron beams with energies exceeding 1 GeV a different mechanism is required to trap charge into low density wakes. By introducing small concentrations of high-Z gas to the nominal He background the ionization-induced injection mechanism is enabled. Electron trapping is observed at densities as low as 1.3 x 1018 cm-3 in a gas cell target, and 1.45 GeV electrons are demonstrated for the first time from LWFA. This is currently the highest electron energy ever produced from LWFA. The ionization-induced trapping mechanism is also shown to generate quasi-continuous electron beam energies, which is undesirable for accelerator applications. By limiting the region over which ionization-induced trapping occurs, the energy spread of the electron beams can be controlled. The development of a novel two-stage gas cell target provides the capability to tailor the gas composition in the longitudinal direction, and confine the trapping process to occur only in a

  18. Measurements of beat wave accelerated electrons in a toroidal plasma

    International Nuclear Information System (INIS)

    Rogers, J.H.

    1992-06-01

    Electrons are accelerated by large amplitude electron plasma waves driven by counter-propagating microwaves with a difference frequency approximately equal to the electron plasma frequency. Energetic electrons are observed only when the phase velocity of the wave is in the range 3v e ph e (v ph was varied 2v e ph e ), where v e is the electron thermal velocity, (kT e /m e ) 1/2 . As the phase velocity increases, fewer electrons are accelerated to higher velocities. The measured current contained in these accelerated electrons has the power dependence predicted by theory, but the magnitude is lower than predicted

  19. One-dimensional theory and simulation of acceleration in relativistic electron beam Raman scattering

    International Nuclear Information System (INIS)

    Abe, T.

    1986-01-01

    Raman scattering by a parallel relativistic electron beam was examined analytically and by using the numerical simulation. Incident wave energy can be transferred not only to the scattered electromagnetic wave but also to the beam. That is, the beam can be accelerated by the Doppler-shifted plasma oscillation accompanied by the scattered wave. The energy conversion rates for them were obtained. They increase with the γ value of the electron beam. For the larger γ values of the beam, the energy of the incident wave is mainly transferred to the beam, while in smaller γ, the energy conversion rate to the scattered wave is about 0.2 times that to the beam. Even in smaller γ, the total energy conversion rate is about 0.1

  20. 12 MeV, 4.3 kW electron linear accelerator irradiation application

    International Nuclear Information System (INIS)

    Hang Desheng; Lai Qiji

    2000-01-01

    Characteristics of an electron linear accelerator, which has 6-12 MeV energy, 4.2 kW average beam power is introduced. Results show that it has advantages on improving the characteristics of semiconductor devices such as diodes, triodes, SCR, preventing garlic from sprout, preservation of food, and so on