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Sample records for mev electron source

  1. Simulation of Electron Behavior in PIG Ion Source for 9MeV Cyclotron

    CERN Document Server

    Ghergherehchi, Mitra; Yeon, Yeong- Heum; Chai, Jong- Seo

    2013-01-01

    In this paper, we focus on a PIG source for producing intense H-ions inside a 9MeV cyclotron. The properties of the PIG ion source were simulated for a variety of electric field distributions and magnetic field strengths using CST Particle Studio. After analyzing secondary electron emission (SEE) as a function of both magnetic and electric field strengths, we found that for the modeled PIG geometry a magnetic field strength of 0.2 T provided the best results in term of number of secondary electrons. Furthermore, at 0.2 T the number of secondary electrons proved to be greatest regardless of the cathode potential. Also the modified PIG ion source with quartz insulation tubes was tested in KIRAMS-13 cyclotron by varying gas flow rate and arc current, respectively. The capacity of the designed ion source was also demonstrated by producing plasma inside the constructed 9MeV cyclotron. As a result, the ion source is verified to be capable to produce intense H- beam and high ion beam current for the desired 9 MeV cy...

  2. Dislocation Climb Sources Activated by 1 MeV Electron Irradiation of Copper-Nickel Alloys

    DEFF Research Database (Denmark)

    Barlow, P.; Leffers, Torben

    1977-01-01

    Climb sources emitting dislocation loops are observed in Cu-Ni alloys during irradiation with 1 MeV electrons in a high voltage electron microscope. High source densities are found in alloys containing 5, 10 and 20% Ni, but sources are also observed in alloys containing 1 and 2% Ni. The range......, thermodynamically, there is not complete miscibility in the Cu-Ni system as implied by the published phase diagrams. It is furthermore suggested that these precipitates are platelets of Ni atoms on {100} planes, which would account for the formation of the rectangular loops. The binding energy between vacancies...... of irradiation temperatures corresponding to the highest source densities is approximately 350°–500°C. The climb sources are not related to any pre-existing dislocations resolved in the microscope. The sources emit three types of loop: ‘rectangular’ loops with a100 Burgers vector and {100} habit plane, normal...

  3. A Compact 5 MeV S-Band Electron Linac Based X-Ray Source for Industrial Radiography

    CERN Document Server

    Auditore, Lucrezia; De Pasquale, Domenico; Emanuele, Umberto; Italiano, Antonio; Trifirò, Antonio; Trimarchi, Marina

    2005-01-01

    A compact and reliable X-ray source, based on a 5 MeV, 1 kW, S-band electron linac, has been set up at the Dipartimento di Fisica, Universit\\'a di Messina. This source, coupled with a GOS scintillator screen and a CCD camera, represents an innovative transportable system for industrial radiography and X-ray tomography. Optimization of the parameters influencing the e-gamma conversion and the X-ray beam characteristics have been studied by means of the MCNP-4C2 code. The converter choice is the result of the study of the e-gamma conversion performances for different materials and materials thicknesses. Also the converter position with respect to the linac exit window was studied. The chosen converter consists in a Ta-Cu target inserted close to the linac window. The Cu layer acts as a filter both on the electrons from the source and on the low energy X-rays. The X-ray beam angular profile was studied by means of GafChromic films with and without collimation. In the final source project, a collimation system pr...

  4. 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.

  5. A Complete Reporting of MCNP6 Validation Results for Electron Energy Deposition in Single-Layer Extended Media for Source Energies <= 1-MeV

    Energy Technology Data Exchange (ETDEWEB)

    Dixon, David A. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Hughes, Henry Grady [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-05-04

    In this paper, we expand on previous validation work by Dixon and Hughes. That is, we present a more complete suite of validation results with respect to to the well-known Lockwood energy deposition experiment. Lockwood et al. measured energy deposition in materials including beryllium, carbon, aluminum, iron, copper, molybdenum, tantalum, and uranium, for both single- and multi-layer 1-D geometries. Source configurations included mono-energetic, mono-directional electron beams with energies of 0.05-MeV, 0.1-MeV, 0.3- MeV, 0.5-MeV, and 1-MeV, in both normal and off-normal angles of incidence. These experiments are particularly valuable for validating electron transport codes, because they are closely represented by simulating pencil beams incident on 1-D semi-infinite slabs with and without material interfaces. Herein, we include total energy deposition and energy deposition profiles for the single-layer experiments reported by Lockwood et al. (a more complete multi-layer validation will follow in another report).

  6. A Galactic Cosmic Ray Electron Spectrum from 2 MeV to 2 TeV That Fits Voyager 5-60 MeV Data at Low Energies and PAMELA and AMS-2 Data at 10 GeV Using an Electron Source Spectrum E^-2.25 A Calculation Using a Monte Carlo Diffusion Model

    CERN Document Server

    Webber, W R

    2015-01-01

    In this paper we fit the observed galactic cosmic ray electron spectrum from a few MeV to 1 TeV. New data from Voyager from 5-60 MeV beyond the heliopause is used along with high energy data from the PAMELA, FERMI and AMS-2 instruments in Earth orbit. Using a Monte Carlo diffusion model for galactic propagation we obtain a source rigidity spectrum with a spectral index =-2.25 independent of energy below 10 GeV, possibly steepening above 10 GeV to 2.40 at the highest energies. This spectrum will fit the electron data over 5 orders of magnitude to within + 10% at both low and high energies. This steepening of the electron source spectrum could be an important feature of the acceleration process, e.g., synchrotron loss during acceleration could steepen the source spectrum. This fit requires only a single break in the rigidity dependence of the diffusion coefficient by ~1.0 power in the exponent at about 1.0 GV. The calculations also predict the distribution of electrons perpendicular to the galactic disk. The ga...

  7. Temporal Structure of MeV Electron Precipitation

    Science.gov (United States)

    Millan, R. M.; Lorentzen, K. R.; Lin, R. P.; Smith, D. M.

    2001-12-01

    On January 12, 2000, the MAXIS (MeV Auroral X-ray Imaging and Spectroscopy) long duration balloon experiment was launched from McMurdo, Antarctica carrying x-ray instrumentation designed to search for MeV electron precipitation similar to the event observed in 1996 over Kiruna, Sweden (L=5.8). MAXIS detected seven x-ray bursts with significant flux extending above 0.8 MeV during the 18 day flight in addition to extended periods of softer X-ray activity. These seven events are characterized by an extremely flat spectrum ( ~E-1.7) indicating that the bulk of precipitating electrons producing the x-rays is at relativistic energies. The bursts were detected between magnetic latitudes 58o-67o (corresponding to L-values between 3.8-6.7) with durations varying from several minutes to several hours. The MeV bursts were found to occur preferentially in the late afternoon/dusk sectors (14:30-00:00 MLT) while softer precipitation was detected at all magnetic local times. Two of the strongest MeV events detected by MAXIS show strong modulation of the x-ray count rate at ULF timescales ( ~150 s) similar to modulations observed during the Kiruna event at 100-200 s. We present results from temporal analysis of the MAXIS germanium spectrometer data and examine ground-based and spacecraft observations for evidence of coincident ULF wave activity.

  8. Measurements of 1.9 MeV electron Bremsstrahlung

    Energy Technology Data Exchange (ETDEWEB)

    Lopez-Pino, Neivy; Cabal, Fatima Padilla; D' Alessandro, Katia [Instituto Superior de Tecnologias y Ciencias Aplicadas (InSTEC), La Habana (Cuba); Maidana, Nora Lia; Vanin, Vito Roberto; Martins, Marcos Nogueira; Malafronte, Alexandre; Bonini, Alfredo L. [Universidade de Sao Paulo (IF/USP), SP (Brazil). Inst. de Fisica. Lab. do Acelerador Linear; Sempau, Josep [Universitat Politecnica de Catalunya, Barcelona (Spain)

    2011-07-01

    Full text: Bremsstrahlung Cross section of 1.9 MeV electrons in Ti, Ag, and Au were measured at the Microtron accelerator of the IFUSP. Target mass surface density was in the range 0.1 to 1 mg/cm{sup 2} and the electron current varied from 3 to 30 nA, measured by a Faraday cup. The spectra were measured at three angles (30 deg; 90 deg and 60 deg) using a shielded p-type HPGe detector with an spectroscopy amplifier with pile-up rejection and a fast ADC. A 20 cm in length and 1.2 cm in diameter Pb collimator was placed in front of the detector to reduce the contribution of radiation scattered in the irradiation chamber or other background sources. With the goal of increasing the peak to total gamma-ray efficiency, the collimator hole was placed with its axis parallel to the coaxial detector symmetry axis, but displaced 1.4 cm to the right of the detector crystal axis. Hence, the Ge thickness exposed directly to the Bremsstrahlung beam was about 5 times bigger than that in the crystal axis, where the n-contact hole is located. The detector response functions were obtained by Monte Carlo simulations based on experimentally determined detector dimensions, in a procedure described in a companion paper submitted to this conference (Response function of a p-type Ge detector). Two energy bins: 50 keV and 1 keV were used in the Bremsstrahlung spectrum deconvolution. The first one was employed to determine the energy differential cross section from 0.1 to 1.9 MeV, and the second one for a more specific spectra study, in the high frequency limit or 'tip region'. The experimental spectrum was corrected for pile-up, with a simple model that assumes that the amplifier pile-up rejection resolving time is the same for all measured energies, and the photon background, measured with the target retracted from the beam. The Bremsstrahlung spectra B were obtained as: B = R{sup -}1 X E, where R is the matrix of the detector response function and E the recorded spectrum vector

  9. An intense 14 MeV neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Su Tongling; Sun Biehe; Yang Baotai; Piao Yubo; Shui Yongqing; Chen Kefan; Wang Xuezhi; Yang Cheng; Niu Zhanqi; Liu Yanton; Pan Minshen; Hong Zhongti; Chen Qin (Lanzhou Univ., GS (China). Inst. of Nuclear Research)

    1990-02-15

    A 3x10{sup 12} n/s source of 14 MeV neutrons is described in this paper. The neutrons are produced by the T(d,n){sup 4}He reaction under a 30 mA, 300 keV deuteron beam bombarding a water-cooled, rotating titanium-tritide target. The size of the beam spot on the target is 1.8 cm, and at the distance of closest approach to the source a neutron flux of 5x10{sup 11} n/cm{sup 2} s is obtained. (orig.).

  10. Dosimetric comparison of 4 MeV and 6 MeV electron beams for total skin irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jung In; Park, So Yeon; Park, Jong Min; Ye, Sung Joon; Kim, Il Han [Dept. of Radiation Oncology, Seoul National University Hospital, Seoul (Korea, Republic of)

    2014-11-15

    Total skin electron irradiation (TSEI) was developed by Stanford University in the 1950s and introduced for the treatment of mycosis fungoides, the most common form of cutaneous T-cell lymphoma which generally affects the skin. In this study, dosimetric aspects of TSEI consisting of a 4 MeV beam with no spoiler were investigated in comparison to a nominal 6 MeV beam applications was evaluated. The suggested 4 MeV beam for TSEI could be applied to shallow depth skin diseases and to electron boost as second treatment course.

  11. A direct electron detector for time-resolved MeV electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Vecchione, T.; Denes, P.; Jobe, R. K.; Johnson, I. J.; Joseph, J. M.; Li, R. K.; Perazzo, A.; Shen, X.; Wang, X. J.; Weathersby, S. P.; Yang, J.; Zhang, D.

    2017-03-01

    The introduction of direct electron detectors enabled the structural biology revolution of cryogenic electron microscopy. Direct electron detectors are now expected to have a similarly dramatic impact on time-resolved MeV electron microscopy, particularly by enabling both spatial and temporal jitter correction. Here we report on the commissioning of a direct electron detector for time-resolved MeV electron microscopy. The direct electron detector demonstrated MeV single electron sensitivity and is capable of recording megapixel images at 180 Hz. The detector has a 15-bit dynamic range, better than 30-μmμm spatial resolution and less than 20 analogue-to-digital converter count RMS pixel noise. The unique capabilities of the direct electron detector and the data analysis required to take advantage of these capabilities are presented. The technical challenges associated with generating and processing large amounts of data are also discussed.

  12. Modification and alignment of beam line of 10 MeV RF electron beam accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Barnwal, R; Ghodke, S R; Bhattacharjee, D; Kumar, M; Jayaprakash, D; Chindarkar, A R; Mishra, R L; Kumar, M; P, Dixit K; S, Acharya; Barje, S R; Lawangare, N K; C, Saroj P; Nimje, V T; Chandan, S; Tillu, A R; V, Sharma; Chavan, R B [Accelerator and Pulse Power Division, BARC, Mumbai, India-400085 (India); Dolas, S [Centre for Design and Manufacturing, BARC, Mumbai, India-400085 (India); Kulkarni, S Y [SAMEER, IIT Powai campus, Mumbai, India-400076 (India)], E-mail: rajesh_barc47@indiatimes.com (and others)

    2008-05-01

    A 10 MeV, 10 kW RF industrial Electron linac designed and developed at BARC is installed at the Electron Beam Center Kharghar, Navi Mumbai. The entire RF accelerator assembly consists of Electron gun, RF source, RF linac structure, Beam diagnostic chamber, Drift tube, Scanning magnet, Beam sensing aperture, Scan horn, and is spread over two floors at EBC. The paper discusses in detail about the alignment procedure adopted for the equipments of 10 MeV RF beamline. The complete electron beamline will be maintained under ultra high vacuum of the order of 10-7 torr. The paper discusses about the present problem of alignment, measurement technique of alignment, reason for misalignment, possible ways to solve the problem, equipment used for alignment, supports and arrestors, verification of alignment under vacuum.

  13. Modification & alignment of beam line of 10 MeV RF electron beam accelerator

    Science.gov (United States)

    Barnwal, R.; Ghodke, S. R.; Bhattacharjee, D.; Kumar, M.; Jayaprakash, D.; Chindarkar, A. R.; Mishra, R. L.; Dolas, S.; Kulkarni, S. Y.; Kumar, M.; P, Dixit K.; S, Acharya; Barje, S. R.; Lawangare, N. K.; C, Saroj P.; Nimje, V. T.; Chandan, S.; Tillu, A. R.; V, Sharma; Chavan, R. B.; V, Yadav; P, Roychowdhury; Mittal, K. C.; Chakravarthy, D. P.; Ray, A. K.

    2008-05-01

    A 10 MeV, 10 kW RF industrial Electron linac designed and developed at BARC is installed at the Electron Beam Center Kharghar, Navi Mumbai. The entire RF accelerator assembly consists of Electron gun, RF source, RF linac structure, Beam diagnostic chamber, Drift tube, Scanning magnet, Beam sensing aperture, Scan horn, and is spread over two floors at EBC. The paper discusses in detail about the alignment procedure adopted for the equipments of 10 MeV RF beamline. The complete electron beamline will be maintained under ultra high vacuum of the order of 10-7 torr. The paper discusses about the present problem of alignment, measurement technique of alignment, reason for misalignment, possible ways to solve the problem, equipment used for alignment, supports & arrestors, verification of alignment under vacuum

  14. Single-shot MeV transmission electron microscopy with picosecond temporal resolution

    CERN Document Server

    Li, R K

    2014-01-01

    Pushing the limits in temporal resolution for transmission electron microscopy (TEM) requires a revolutionary change in the electron source technology. In this paper we study the possibility of employing a radiofrequency photoinjector as the electron source for a time-resolved TEM. By raising the beam energy to the relativistic regime we minimize the space charge effects which otherwise limit the spatio-temporal resolution of the instrument. Analysis and optimization of the system taking into account the achievable beam brightness, electron flux on the sample, chromatic and spherical aberration of the electron optic system, and space charge effects in image formation are presented and supported by detailed numerical modeling. The results demonstrate the feasibility of 10 nanometer - 10 picosecond spatio-temporal resolution single-shot MeV TEM.

  15. Photonuclear and Radiation Effects Testing with a Refurbished 20 MeV Medical Electron Linac

    CERN Document Server

    Webb, Timothy; Beezhold, Wendland; De Veaux, Linda C; Harmon, Frank; Petrisko, Jill E; Spaulding, Randy

    2005-01-01

    An S-band 20 MeV electron linear accelerator formerly used for medical applications has been recommissioned to provide a wide range of photonuclear activation studies as well as various radiation effects on biological and microelectronic systems. Four radiation effect applications involving the electron/photon beams are described. Photonuclear activation of a stable isotope of oxygen provides an active means of characterizing polymer degradation. Biological irradiations of microorganisms including bacteria were used to study total dose and dose rate effects on survivability and the adaptation of these organisms to repeated exposures. Microelectronic devices including bipolar junction transistors (BJTs) and diodes were irradiated to study photocurrent from these devices as a function of peak dose rate with comparisons to computer modeling results. In addition, the 20 MeV linac may easily be converted to a medium energy neutron source which has been used to study neutron damage effects on transistors.

  16. CESAR, 2 MeV electron storage ring.

    CERN Multimedia

    1967-01-01

    CESAR (CERN Electron Storage and Accumulation Ring) was built as a study-model for the ISR (Intersecting Storage Rings). The model had to be small (24 m circumference) and yet the particles had to be highly relativistic, which led to the choice of electrons. On the other hand, in order to model the behaviour of protons, effects from synchrotron radiation had to be negligible, which meant low magnetic fields (130 G in the bending magnets) and a corresponding low energy of 1.75 MeV. All the stacking (accumulation) procedures envisaged for the ISR were proven with CESAR, and critical aspects of transverse stability were explored. Very importantly, CESAR was the test-bed for the ultrahigh vacuum techniques and components, essential for the ISR, with a final pressure of 6E-11 Torr. The CESAR project was decided early in 1960, design was completed in 1961 and construction in 1963. After an experimental period from 1964 to 1967, CESAR was dismantled in 1968.

  17. CESAR, 2 MeV electron storage ring; general view.

    CERN Multimedia

    1964-01-01

    CESAR (CERN Electron Storage and Accumulation Ring) was built as a study-model for the ISR (Intersecting Storage Rings). The model had to be small (24 m circumference) and yet the particles had to be highly relativistic, which led to the choice of electrons. On the other hand, in order to model the behaviour of protons, effects from synchrotron radiation had to be negligible, which meant low magnetic fields (130 G in the bending magnets) and a corresponding low energy of 1.75 MeV. All the stacking (accumulation) procedures envisaged for the ISR were proven with CESAR, and critical aspects of transverse stability were explored. Very importantly, CESAR was the test-bed for the ultrahigh vacuum techniques and components, essential for the ISR, with a final pressure of 6E-11 Torr. The CESAR project was decided early in 1960, design was completed in 1961 and construction in 1963. After an experimental period from 1964 to 1967, CESAR was dismantled in 1968.

  18. 1 MeV, 10 kW DC electron accelerator for industrial applications

    Science.gov (United States)

    Nayak, B.; Acharya, S.; Bhattacharjee, D.; Bakhtsingh, R. I.; Rajan, R.; Sharma, D. K.; Dewangan, S.; Sharma, V.; Patel, R.; Tiwari, R.; Benarjee, S.; Srivastava, S. K.

    2016-03-01

    Several modern applications of radiation processing like medical sterilization, rubber vulcanization, polymerization, cross-linking and pollution control from thermal power stations etc. require D.C. electron accelerators of energy ranging from a few hundred keVs to few MeVs and power from a few kilowatts to hundreds of kilowatts. To match these requirements, a 3 MeV, 30 kW DC electron linac has been developed at BARC, Mumbai and current operational experience of 1 MeV, 10 kW beam power will be described in this paper. The LINAC composed mainly of Electron Gun, Accelerating Tubes, Magnets, High Voltage source and provides 10 kW beam power at the Ti beam window stably after the scanning section. The control of the LINAC is fully automated. Here Beam Optics study is carried out to reach the preferential parameters of Accelerating as well as optical elements. Beam trials have been conducted to find out the suitable operation parameters of the system.

  19. Backward Secondary Electron Emission Yield of Thick Targets Induced by MeV Ions

    Institute of Scientific and Technical Information of China (English)

    JIANG Lei; ZHAO Guo-Qing; ZHOU Zhu-Ying

    2000-01-01

    The backward secondary electron emission yields of MeV ions (H+, He+, He++, Cl, Si, and Cu ) impinging on thick carbon and gold targets are studied. The measured results for H+ (1MeV ≤ E ≤ 5MeV) on carbon are proportional to the electronic stopping power. Our experimental data and fitting formula of yields for H+ (1 MeV≤ E≤ 4.5MeV) impacting Au are compared with the theoretical expectation. The influence of the collective field and the charge state of ions on the secondary electron emission yield is discussed.

  20. A Transformative Imaging Capability Using Laser Driven Multi MeV Photon Sources

    Science.gov (United States)

    Gautier, Donald; Espy, Michelle; Palaniyappan, Sasi; Mendez, Jacob; Nelson, Ronald; Hunter, James; Fernandez, Juan; los alamos national laboratory Team

    2016-10-01

    Recent results from the LANL Trident Laser demonstrate the practical use of a laser of this class ( 70 J, 600 fs) as a multi MeV photon source. The utilization of novel targets operating in the relativistic transparency regime of laser-plasmas has enabled this development. The electron population made from these targets, when coupled to a suitable high-Z converter foil placed near the laser target, produces an intense >1 MeV photon source with a small source size compared to conventional sources. When coupled with efficient imaging detectors, this laser-driven hard x-ray source provides new capabilities to address current non-destructive and dynamic testing problems that require a quantum jump in resolution. ``Flash'' (pulse picosecond) photon imaging, micro-focus resolution enhancement, good object penetration, and magnification (4x) with sufficient dose (>10 Rad/sr) for practical application have all been demonstrated at the LANL Trident Laser, as summarized in this presentation.

  1. Design of Cavity for 10 MeV Electron Irradiation Accelerator

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    This article describes the 10 MeV high-power electron irradiation accelerator. This accelerator can output varied energy electron beam which the highest energy is 10 MeV or shooting target produce X-rays for industrial radiation processing.

  2. Characteristic parameters of 6--21 MeV electron beams from a 21 MeV linear accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Al-Ghazi, M.S.A.L. (Department of Medical Physics, Thunder Bay Regional Cancer Centre, Ontario Cancer Treatment and Research Foundation, Thunder Bay, Ontario P7A 7T1, (Canada) Department of Physics, Lakehead University, Thunder Bay, Ontario P7B 5E1, (Canada) Lingman, D. Department of Medical Physics, Thunder Bay Regional Cancer Centre, Ontario Cancer Treatment and Research Foundation, Thunder Bay, Ontario P7A 7T1, (Canada) Department of Computer Science, Lakehead University, Thunder Bay, Ontario P7B 5E1, (Canada)); Gilbert, L.D. (Thekkumthala, J. Department of Medical Physics, Thunder Bay Regional Cancer Centre, Ontario Cancer Treatment and Research Foundation, Thunder Bay, Ontario P7A 7T1, (Canada))

    1991-07-01

    Dosimetry measurements have been carried out for the electron beams produced by a linear accelerator at energies 6, 8, 10, 14, 18, and 21 MeV. Characteristic parameters of the central axis dose distributions were derived and compared to corresponding values of electron beams from other accelerators in clinical use where such a comparison is appropriate. A comprehensive set of dosimetric parameters is provided for electron beam treatment planning. The data include central axis depth dose, range--energy parameters, beam penumbra and uniformity.

  3. Diagnostics for a 1.2 kA, 1 MeV, electron induction injector

    Science.gov (United States)

    Houck, T. L.; Anderson, D. E.; Eylon, S.; Henestroza, E.; Lidia, S. M.; Vanecek, D. L.; Westenskow, G. A.; Yu, S. S.

    1998-12-01

    We are constructing a 1.2 kA, 1 MeV, electron induction injector as part of the RTA program, a collaborative effort between LLNL and LBNL to develop relativistic klystrons for Two-Beam Accelerator applications. The RTA injector will also be used in the development of a high-gradient, low-emittance, electron source and beam diagnostics for the second axis of the Dual Axis Radiographic Hydrodynamic Test (DARHT) Facility. The electron source will be a 3.5″-diameter, thermionic, flat-surface, m-type cathode with a maximum shroud field stress of approximately 165 kV/cm. Additional design parameters for the injector include a pulse length of over 150 ns flat top (1% energy variation), and a normalized edge emittance of less than 200 π-mm-mr. Precise measurement of the beam parameters is required so that performance of the RTA injector can be confidently scaled to the 4 kA, 3 MeV, and 2-microsecond pulse parameters of the DARHT injector. Planned diagnostics include an isolated cathode with resistive divider for direct measurement of current emission, resistive wall and magnetic probe current monitors for measuring beam current and centroid position, capacitive probes for measuring A-K gap voltage, an energy spectrometer, and a pepperpot emittance diagnostic. Details of the injector, beam line, and diagnostics are presented.

  4. Diagnostics for a 1.2 kA, 1 MeV electron induction injector

    Energy Technology Data Exchange (ETDEWEB)

    Houck, T.L.; Anderson, D.E.; Eylon, S.; Henestroza, E.; Lidia, S.M.; Vanecek, D.L.; Westenskow, G.A.; Yu, S.S.

    1998-05-11

    We are constructing a 1.2-kA, 1-MeV, electron induction injector as part of the RTA program, a collaborative effort between LLNL and LBNL to develop relativistic klystrons for Two-Beam Accelerator applications. The RTA injector will also be used in the development of a high-gradient, low-emittance, electron source and beam diagnostics for the second axis of the Dual Axis Radiographic Hydrodynamic Test (DARHT) Facility. The electron source will be a 3.5``-diameter, thermionic, flat-surface, m-type cathode with a maximum shroud field stress of approximately 165 kV/cm. Additional design parameters for the injector include a pulse length of over 150-ns flat top (1% energy variation), and a normalized edge emittance of less than 200 {pi}-mm-mr. Precise measurement of the beam parameters is required so that performance of the RTA injector can be confidently scaled to the 4-kA, 3-MeV, and 2-microsecond pulse parameters of the DARHT injector. Planned diagnostics include an isolated cathode with resistive divider for direct measurement of current emission, resistive wall and magnetic probe current monitors for measuring beam current and centroid position, capacitive probes for measuring A-K gap voltage, an energy spectrometer, and a pepper-pot emittance diagnostic. Details of the injector, beam line, and diagnostics are presented.

  5. Two-color infrared FEL facility employing a 250-MeV linac injector of Saga synchrotron light source

    CERN Document Server

    Tomimasu, T; Koga, N; Hashiguchi, Y; Ochiai, Y; Ishibashi, M

    2001-01-01

    A two-color infrared free electron laser (FEL) facility is proposed. This FEL facility will employ a new 250-MeV linac injector of the Saga synchrotron light source (SLS). The linac has two operation modes: short macropulse mode of 1 mu s at 250 MeV is for injection to a 1.4-GeV storage ring and long macropulse mode of 13 mu s at 40 MeV is for the two-color FEL facility. The two-color FEL uses a single electron beam and simultaneously provides both infrared (IR) and far-IR laser pulses for pump-probe studies of quantum-well structures and studying vibrational relaxation of molecules. The Saga SLS will be operated in 2004 to promote material science, bio-medical and industrial applications in Kyushu.

  6. Highly Stripped Ion Sources for MeV Ion Implantation

    Energy Technology Data Exchange (ETDEWEB)

    Hershcovitch, Ady

    2009-06-30

    Original technical objectives of CRADA number PVI C-03-09 between BNL and Poole Ventura, Inc. (PVI) were to develop an intense, high charge state, ion source for MeV ion implanters. Present day high-energy ion implanters utilize low charge state (usually single charge) ion sources in combination with rf accelerators. Usually, a MV LINAC is used for acceleration of a few rnA. It is desirable to have instead an intense, high charge state ion source on a relatively low energy platform (de acceleration) to generate high-energy ion beams for implantation. This de acceleration of ions will be far more efficient (in energy utilization). The resultant implanter will be smaller in size. It will generate higher quality ion beams (with lower emittance) for fabrication of superior semiconductor products. In addition to energy and cost savings, the implanter will operate at a lower level of health risks associated with ion implantation. An additional aim of the project was to producing a product that can lead to long­ term job creation in Russia and/or in the US. R&D was conducted in two Russian Centers (one in Tomsk and Seversk, the other in Moscow) under the guidance ofPVI personnel and the BNL PI. Multiple approaches were pursued, developed, and tested at various locations with the best candidate for commercialization delivered and tested at on an implanter at the PVI client Axcelis. Technical developments were exciting: record output currents of high charge state phosphorus and antimony were achieved; a Calutron-Bemas ion source with a 70% output of boron ion current (compared to 25% in present state-of-the-art). Record steady state output currents of higher charge state phosphorous and antimony and P ions: P{sup 2+} (8.6 pmA), P{sup 3+} (1.9 pmA), and P{sup 4+} (0.12 pmA) and 16.2, 7.6, 3.3, and 2.2 pmA of Sb{sup 3+} Sb {sup 4 +}, Sb{sup 5+}, and Sb{sup 6+} respectively. Ultimate commercialization goals did not succeed (even though a number of the products like high

  7. Electron Beam Ion Sources

    OpenAIRE

    Zschornacka, G.; Schmidt, M.; Thorn, A.

    2014-01-01

    Electron beam ion sources (EBISs) are ion sources that work based on the principle of electron impact ionization, allowing the production of very highly charged ions. The ions produced can be extracted as a DC ion beam as well as ion pulses of different time structures. In comparison to most of the other known ion sources, EBISs feature ion beams with very good beam emittances and a low energy spread. Furthermore, EBISs are excellent sources of photons (X-rays, ultraviolet, extreme ultraviole...

  8. Production of Highly Polarized Positrons Using Polarized Electrons at MeV Energies

    Science.gov (United States)

    Abbott, D.; Adderley, P.; Adeyemi, A.; Aguilera, P.; Ali, M.; Areti, H.; Baylac, M.; Benesch, J.; Bosson, G.; Cade, B.; Camsonne, A.; Cardman, L. S.; Clark, J.; Cole, P.; Covert, S.; Cuevas, C.; Dadoun, O.; Dale, D.; Dong, H.; Dumas, J.; Fanchini, E.; Forest, T.; Forman, E.; Freyberger, A.; Froidefond, E.; Golge, S.; Grames, J.; Guèye, P.; Hansknecht, J.; Harrell, P.; Hoskins, J.; Hyde, C.; Josey, B.; Kazimi, R.; Kim, Y.; Machie, D.; Mahoney, K.; Mammei, R.; Marton, M.; McCarter, J.; McCaughan, M.; McHugh, M.; McNulty, D.; Mesick, K. E.; Michaelides, T.; Michaels, R.; Moffit, B.; Moser, D.; Muñoz Camacho, C.; Muraz, J.-F.; Opper, A.; Poelker, M.; Réal, J.-S.; Richardson, L.; Setiniyaz, S.; Stutzman, M.; Suleiman, R.; Tennant, C.; Tsai, C.; Turner, D.; Ungaro, M.; Variola, A.; Voutier, E.; Wang, Y.; Zhang, Y.; PEPPo Collaboration

    2016-05-01

    The Polarized Electrons for Polarized Positrons experiment at the injector of the Continuous Electron Beam Accelerator Facility has demonstrated for the first time the efficient transfer of polarization from electrons to positrons produced by the polarized bremsstrahlung radiation induced by a polarized electron beam in a high-Z target. Positron polarization up to 82% have been measured for an initial electron beam momentum of 8.19 MeV /c , limited only by the electron beam polarization. This technique extends polarized positron capabilities from GeV to MeV electron beams, and opens access to polarized positron beam physics to a wide community.

  9. Field emission electron source

    Science.gov (United States)

    Zettl, Alexander Karlwalter; Cohen, Marvin Lou

    2000-01-01

    A novel field emitter material, field emission electron source, and commercially feasible fabrication method is described. The inventive field emission electron source produces reliable electron currents of up to 400 mA/cm.sup.2 at 200 volts. The emitter is robust and the current it produces is not sensitive to variability of vacuum or the distance between the emitter tip and the cathode. The novel emitter has a sharp turn-on near 100 volts.

  10. LIGHT SOURCE: Physical design of a 10 MeV LINAC for polymer radiation processing

    Science.gov (United States)

    Feng, Guang-Yao; Pei, Yuan-Ji; Wang, Lin; Zhang, Shan-Cai; Wu, Cong-Feng; Jin, Kai; Li, Wei-Min

    2009-06-01

    In China, polymer radiation processing has become one of the most important processing industries. The radiation processing source may be an electron beam accelerator or a radioactive source. Physical design of an electron beam facility applied for radiation crosslinking is introduced in this paper because of it's much higher dose rate and efficiency. Main part of this facility is a 10 MeV travelling wave electron linac with constant impedance accelerating structure. A start to end simulation concerning the linac is reported in this paper. The codes Opera-3d, Poisson-superfish and Parmela are used to describe electromagnetic elements of the accelerator and track particle distribution from the cathode to the end of the linac. After beam dynamic optimization, wave phase velocities in the structure have been chosen to be 0.56, 0.9 and 0.999 respectively. Physical parameters about the main elements such as DC electron gun, iris-loaded periodic structure, solenoids, etc, are presented. Simulation results proves that it can satisfy the industrial requirement. The linac is under construction. Some components have been finished. Measurements proved that they are in a good agreement with the design values.

  11. Polarized Electron Source Developments

    Energy Technology Data Exchange (ETDEWEB)

    Charles K. Sinclair

    1990-02-23

    Presently, only two methods of producing beams of polarized electrons for injection into linear accelerators are in use. Each of these methods uses optical pumping by circularly polarized light to produce electron polarization. In one case, electron polarization is established in metastable helium atoms, while in the other case, the polarized electrons are produced in the conduction band of appropriate semiconductors. The polarized electrons are liberated from the helium metastable by chemi-ionization, and from the semiconductors by lowering the work function at the surface of the material. Developments with each of these sources since the 1988 Spin Physics Conference are reviewed, and the prospects for further improvements discussed.

  12. Pulsed Plasma Electron Sources

    Science.gov (United States)

    Krasik, Yakov

    2008-11-01

    Pulsed (˜10-7 s) electron beams with high current density (>10^2 A/cm^2) are generated in diodes with electric field of E > 10^6 V/cm. The source of electrons in these diodes is explosive emission plasma, which limits pulse duration; in the case E Hadas and Ya. E. Krasik, Europhysics Lett. 82, 55001 (2008).

  13. 10MeV/20kW Electron Linac for Irradiation Microwave System

    Institute of Scientific and Technical Information of China (English)

    WU; Qing-feng; ZHU; Zhi-bin; WANG; Xiu-long; LIU; Bao-jie; HU; Tao

    2015-01-01

    Microwave system is one of main subsystems of 10 MeV/20kW electron irradiating linac.It provides accelerating tube with microwave power,and accelerates electron beam to design energy,high-energy electron beam is ultimately used for irradiation processing.In order to meet the requirements of the

  14. The KAERI 10 MeV Electron Linac - Description and Operational Manual

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Byung Cheol; Park, Seong Hee; Jung, Young Uk; Han, Young Hwan; Kang, Hee Young

    2005-06-15

    The objective of this technical report is to guide the right operation and maintenance of the KAERI electron linac system. The KAERI electron linac system consists of 2 MeV injector based on 176 MHz Normal conducting RF (Radio Frequency)cavity and 10 MeV main accelerator based on 352 MHz Superconducting RF cavity, electron beamlines (injection and extraction). Since a electron accelerator generates hazard radiation, this system is located at the shielded room in basement and we can operate the system using the remote control system. It includes the description and the operational manual as well as the detailed technical direction for trouble shooting.

  15. Design of 7 MeV electron beams for breast radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jon In; Kim, Jung In; Kwon, Hyuck Jun [Interdisplinary Program in Radiation Applied Life Science, Seoul National University Graduate School, Seoul (Korea, Republic of); Ha, Sung Whan; Kim, Il Han [Dept. of Radiation Oncology, Seoul National University College of Medicine, Seoul (Korea, Republic of); Lee, Hyun Suk; Ye, Sung Joon [Program in Biomedical Radiation Sciences, Dept. of Transdisciplinary Studies, Graduate School of Convergence Science and Technology, Seoul National University, Seoul (Korea, Republic of)

    2013-04-15

    For treating early stage breast cancer, breast conserving therapy with lumpectomy followed by radiation therapy has been preferred as the standard method Irradiation technique consists of whole breast irradiation of 50.0 Gy and supplemental boost of 10 Gy to the tumor bed. The 'boost' to supplement the dose to the highest risk breast tissue around the lumpectomy following whole breast irradiation (WBI) improves in-breast local control. Electron beams have been favored radiation as boost irradiation. Because of limited depth in electron beams, it is possible to reduce the dose for unwished organ such as lung and heart in located in deeper region. Traditionally, electron beams can be modified using a bolus. The use of bolus conforms 90% isodose curve of a single energy electron beam to the distal edge of the target volume. However, it often increases the skin dose with electron beams of energy below 10 MeV. Therefore, with an aim to simultaneously control the penetration depth of the electron beams and the skin dose, we produced the new 7 MeV electron beam by modulating 9 MeV electron beams available in clinical linear accelerators. In this study, we show that the 7 MeV electron beam is appropriate for treatment of patient with a tumor bed located in clinical depth (R90 – R80)

  16. Electron Beam Ion Sources

    CERN Document Server

    Zschornacka, G.; Thorn, A.

    2013-12-16

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

  17. Design of an MeV ultra-fast electron diffraction experiment at Tsinghua university

    Institute of Scientific and Technical Information of China (English)

    LI Ren-Kai; TANG Chuan-Xiang; HUANG Wen-Hui; DU Ying-Chao; SHI Jia-Ru; YAN Li-Xin

    2009-01-01

    Time-resolved MeV ultra-fast electron difiraction(UED)is a powerful tool for structure dynamics studies.In this paper.we present a design of a MeV UED facility based on a photocathode RF gun at Tsinghua University.Electron beam qualities are optimized with numerical simulations,indicating that resolutions of 250 fs and 0.01 A.and bunch charge exceeding 105 electrons are expected with technically achievable machine parameters.Status of experiment preparation is also presented.

  18. POSITRON-ELECTRON DECAY OF SI-28, AT AN EXCITATION-ENERGY OF 50-MEV

    NARCIS (Netherlands)

    BUDA, A; BACELAR, JC; BALANDA, A; VANDERPLOEG, H; SUJKOWSKI, Z; VANDERWOUDE, A

    1993-01-01

    The electron-positron pair decay of Si-28 at 50 MeV excitation produced by the isospin T=0 (alpha + Mg-24) and the mixed isospin T=0,1 (He-3 + Mg-25) reactions has been studied using a special designed Positron-Electron pair spectrometer PEPSI.

  19. POSITRON-ELECTRON DECAY OF SI-28, AT AN EXCITATION-ENERGY OF 50-MEV

    NARCIS (Netherlands)

    BUDA, A; BACELAR, JC; BALANDA, A; VANDERPLOEG, H; SUJKOWSKI, Z; VANDERWOUDE, A

    1993-01-01

    The electron-positron pair decay of Si-28 at 50 MeV excitation produced by the isospin T=0 (alpha + Mg-24) and the mixed isospin T=0,1 (He-3 + Mg-25) reactions has been studied using a special designed Positron-Electron pair spectrometer PEPSI.

  20. Induced photonuclear interaction by Rhodotron-TT200 10 MeV electron beam

    Indian Academy of Sciences (India)

    Farshid Tabbakh; Mojtaba Mostajab Aldaavati; Mahdieh Hoseyni; Khadijeh Rezaee Ebrahim Saraee

    2012-02-01

    In this paper the photonuclear interaction induced by 10 MeV electron beam generating high-intensity neutrons is studied. Since the results depend on the target material, the calculations are performed for Pb, Ta and W targets which have high , in a simple geometry. MCNPX code has been used to simulate the whole process. Also, the results of photon generation has been compared with the experimental results to evaluate the reliability of the calculation. The results show that the obtained neutron flux can reach up to 1012 n/cm2 /s with average energies of 0.9 MeV, 0.4 MeV and 0.9 MeV for these three elements respectively with the maximum heat deposited as 3000 W/c3,4500 W/c3 and 6000 W/c3.

  1. Production of highly-polarized positrons using polarized electrons at MeV energies

    CERN Document Server

    Abbott, D; Adeyemi, A; Aguilera, P; Ali, M; Areti, H; Baylac, M; Benesch, J; Bosson, G; Cade, B; Camsonne, A; Cardman, L S; Clark, J; Cole, P; Covert, S; Cuevas, C; Dadoun, O; Dale, D; Dong, H; Dumas, J; Fanchini, E; Forest, T; Forman, E; Freyberger, A; Froidefond, E; Golge, S; Grames, J; Guèye, P; Hansknecht, J; Harrell, P; Hoskins, J; Hyde, C; Josey, B; Kazimi, R; Kim, Y; Machie, D; Mahoney, K; Mammei, R; Marton, M; McCarter, J; McCaughan, M; McHugh, M; McNulty, D; Mesick, K E; Michaelides, T; Michaels, R; Moffit, B; Moser, D; Camacho, C Muñoz; Muraz, J -F; Opper, A; Poelker, M; Réal, J -S; Richardson, L; Setiniyaz, S; Stutzman, M; Suleiman, R; Tennant, C; Tsai, C; Turner, D; Ungaro, M; Variola, A; Voutier, E; Wang, Y; Zhang, Y

    2016-01-01

    The Polarized Electrons for Polarized Positrons experiment at the injector of the Continuous Electron Beam Accelerator Facility has demonstrated for the first time the efficient transfer of polarization from electrons to positrons produced by the polarized bremsstrahlung radiation induced by a polarized electron beam in a high-$Z$ target. Positron polarization up to 82\\% have been measured for an initial electron beam momentum of 8.19~MeV/$c$, limited only by the electron beam polarization. This technique extends polarized positron capabilities from GeV to MeV electron beams, and opens access to polarized positron beam physics to a wide community.

  2. Photoneutron source based on a compact 10 MeV betatron

    Energy Technology Data Exchange (ETDEWEB)

    Chakhlov, V.L. [Institute of Introscopy, Tomsk Polytechnic University, Tomsk 634028 (Russian Federation); Bell, Z.W. [Lockheed Martin Energy Systems, Inc., Oak Ridge, TN 37831 (United States); Golovkov, V.M. [Institute of Nuclear Physics, Tomsk Polytechnic University, Tomsk 634050 (Russian Federation); Shtein, M.M. [Institute of Introscopy, Tomsk Polytechnic University, Tomsk 634028 (Russian Federation)

    1999-02-11

    Accelerator-based photoneutron sources have enjoyed wide use and offer the advantages of long term stability, ease of control and absence of radioactive materials. We report here measurements of the yield of photoneutrons from a neutron generator using a compact betatron. Electrons were accelerated to energies up to 10 MeV and produced a bremsstrahlung beam with a dose rate of 0.16 Gy/min (at 10 MeV, 1 m from the bremsstrahlung target) to irradiate LiD, Be, depleted U, and Pb neutron-producing targets. The angular distributions of photoneutrons produced by bremsstrahlung beams were measured with a 'long' counter and integrated to determine neutron yield. In addition, neutron time of flight spectra were recorded from all targets using a 15.5 m flight path perpendicular to the photon beam. The maximum observed yields were 4.6x10{sup 7} n/s obtained with 1 kg of LiD, 5.7x10{sup 7} n/s from a 3.3 kg Be block, 6.2x10{sup 6} n/s from 1.5 kg of depleted U, and 7.0x10{sup 6} n/s from 10.7 kg of Pb. Optimization of target dimensions, shape, and positioning is expected to increase the yield from the LiD target by a factor of 35, while optimization of the other targets is expected to yield at most a factor of 10. With the increased yield and a deuteride target, this compact betatron-based system could find application in the interrogation of waste containers for fissile material.

  3. Absolute Calibration of Image Plate for electrons at energy between 100 keV and 4 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Chen, H; Back, N L; Eder, D C; Ping, Y; Song, P M; Throop, A

    2007-12-10

    The authors measured the absolute response of image plate (Fuji BAS SR2040) for electrons at energies between 100 keV to 4 MeV using an electron spectrometer. The electron source was produced from a short pulse laser irradiated on the solid density targets. This paper presents the calibration results of image plate Photon Stimulated Luminescence PSL per electrons at this energy range. The Monte Carlo radiation transport code MCNPX results are also presented for three representative incident angles onto the image plates and corresponding electron energies depositions at these angles. These provide a complete set of tools that allows extraction of the absolute calibration to other spectrometer setting at this electron energy range.

  4. MeV electron acceleration at 1 kHz with <10 mJ laser pulses

    Science.gov (United States)

    Salehi, Fatholah; Goers, Andy; Hine, George; Feder, Linus; Kuk, Donghoon; Miao, Bo; Woodbury, Daniel; Kim, Ki-Yong; Milchberg, Howard

    2017-01-01

    We demonstrate laser driven acceleration of electrons to MeV-scale energies at 1 kHz repetition rate using 1 MeV energy for both He and H gas jets. Such a high repetition rate, high flux ultrafast source has immediate application to time resolved probing of matter for scientific, medical, or security applications, either using the electrons directly or using a high-Z foil converter to generate ultrafast γ-rays. This work is supported by the US Department of Energy, the National Science Foundation, and the Air Force Office of Scientific Research.

  5. M-C simulation of shielding effects of PE, LiH and graphite fibers under 1 MeV electrons and 20 MeV protons

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Shielding effects of different materials under 1 MeV electron and 20 MeV proton beams were simulated with Geant4 code. It was found that shielding effects of polyethylene and graphite fibers are much better than aluminum. Energy depositions in the phantom shielded by the materials are calculated, with the least energy deposition by graphite fiber shielding. The results show that graphite fibers are good radiation shielding material in space programs.

  6. 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.

  7. Ultrafast electron diffraction with megahertz MeV electron pulses from a superconducting radio-frequency photoinjector

    Energy Technology Data Exchange (ETDEWEB)

    Feng, L. W.; Lin, L.; Huang, S. L.; Quan, S. W.; Hao, J. K.; Zhu, F.; Wang, F.; Liu, K. X., E-mail: kxliu@pku.edu.cn [Institute of Heavy Ion Physics and State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871 (China); Jiang, T.; Zhu, P. F.; Fu, F.; Wang, R.; Zhao, L.; Xiang, D., E-mail: dxiang@sjtu.edu.cn [Key Laboratory for Laser Plasmas (Ministry of Education), Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240 (China); IFSA Collaborative Innovation Center, Shanghai Jiao Tong University, Shanghai 200240 (China)

    2015-11-30

    We report ultrafast relativistic electron diffraction operating at the megahertz repetition rate where the electron beam is produced in a superconducting radio-frequency (rf) photoinjector. We show that the beam quality is sufficiently high to provide clear diffraction patterns from gold and aluminium samples. With the number of electrons, several orders of magnitude higher than that from a normal conducting photocathode rf gun, such high repetition rate ultrafast MeV electron diffraction may open up many new opportunities in ultrafast science.

  8. Scale size of magnetic turbulence in tokamaks probed with 30-MeV electrons

    NARCIS (Netherlands)

    Entrop, I.; Cardozo, N. J. L.; R. Jaspers,; Finken, K.H.

    2000-01-01

    Measurements of synchrotron radiation emitted by 30-MeV runaway electrons in the TEXTOR-94 tokamak show that the runaway population decays after switching on neutral beam injection (NBI). The decay starts only with a significant delay, which decreases with increasing NBI heating power. This delay pr

  9. First studies of 500-nm Cherenkov radiation from 255-MeV electrons in a diamond crystal

    Energy Technology Data Exchange (ETDEWEB)

    Takabayashi, Y., E-mail: takabayashi@saga-ls.jp [SAGA Light Source, 8-7 Yayoigaoka, Tosu, Saga 841-0005 (Japan); Fiks, E.I. [National Research Tomsk Polytechnic University, 634050 Tomsk (Russian Federation); Pivovarov, Yu.L. [National Research Tomsk Polytechnic University, 634050 Tomsk (Russian Federation); National Research Tomsk State University, 634050 Tomsk (Russian Federation)

    2015-06-12

    The first experiment on Cherenkov light from 255-MeV electrons passing through a 50-μm-thick diamond crystal in a special geometry allowing extraction of 500-nm Cherenkov light at a right angle with respect to the electron beam direction has been performed at the injector linac of SAGA Light Source accelerator facility. The dependence of 500-nm Cherenkov light intensity (separated by a band-pass filter) on the crystal rotation angle was measured by a CCD detector. The experimentally obtained rocking curve with an intense maximum is theoretically explained as the projector effect of Cherenkov light deflected by the exit surface of the crystal. The width of the rocking curve is explained by the convolution of the standard Tamm–Frank angular distribution of Cherenkov radiation with chromatic aberration, the multiple scattering of electrons in a crystal, and initial electron beam angular divergence. In addition, it is found that the Cherenkov light intensity did not change under the (220) planar channeling condition, which is consistent with a recent theory. - Highlights: • Cherenkov light from 255-MeV electrons in a diamond crystal has been investigated. • The Cherenkov light from channeled electrons has been observed for the first time. • The experimental results are in good agreement with theory.

  10. Pulsed 5 MeV standing wave electron linac for radiation processing

    Science.gov (United States)

    Auditore, L.; Barnà, R. C.; de Pasquale, D.; Italiano, A.; Trifirò, A.; Trimarchi, M.

    2004-03-01

    Several modern applications of radiation processing require compact and self-contained electron accelerators. To match these requirements, a 5MeV, 1kW electron linac has been developed at the Dipartimento di Fisica (Università di Messina) and will be described in this paper. This standing wave accelerator, driven by a 3GHz, 2.5MW magnetron generator, has an autofocusing structure and will be used to study several applications of radiation processing.

  11. The New Sorgentina Fusion Source-NSFS: 14 MeV neutrons for fusion and beyond

    Science.gov (United States)

    Pietropaolo, A.; Console Camprini, P.; Agostini, P.; Amendola, R.; Angelone, M.; Bernardi, D.; Bruni, F.; Capogni, M.; Colognesi, D.; Faccini, R.; Filabozzi, A.; Flammini, D.; Fiori, F.; Frisoni, M.; Grazzi, F.; Pillon, M.; Pizzuto, A.; Quintieri, L.; Sacchetti, F.; Valente, P.

    2016-09-01

    The importance of the design for the realization of an intense 14 MeV neutron facility devoted to test and validate materials suitable for harsh neutron environments, such as a fusion reactor, is well established. The “New Sorgentina” Fusion Source (NSFS) is a project that proposes an intense D-T 14 MeV neutron source achievable with T and D ion beams impinging on 2 m radius rotating targets. NSFS may produce about 1015 n/s at the target and has to be intended as an European facility that maybe realized in a few years, once provided a preliminary technological program devoted to the operation of the ion source in continuous mode, target heat loading/removal, target and tritium handling, inventor as well as site licensing. In this contribution, the main characteristics of NSFS project will be presented and its possible use as a multipurpose facility outlined.

  12. Shielding calculations for industrial 5/7.5MeV electron accelerators using the MCNP Monte Carlo Code

    Science.gov (United States)

    Peri, Eyal; Orion, Itzhak

    2017-09-01

    High energy X-rays from accelerators are used to irradiate food ingredients to prevent growth and development of unwanted biological organisms in food, and by that extend the shelf life of the products. The production of X-rays is done by accelerating 5 MeV electrons and bombarding them into a heavy target (high Z). Since 2004, the FDA has approved using 7.5 MeV energy, providing higher production rates with lower treatments costs. In this study we calculated all the essential data needed for a straightforward concrete shielding design of typical food accelerator rooms. The following evaluation is done using the MCNP Monte Carlo code system: (1) Angular dependence (0-180°) of photon dose rate for 5 MeV and 7.5 MeV electron beams bombarding iron, aluminum, gold, tantalum, and tungsten targets. (2) Angular dependence (0-180°) spectral distribution simulations of bremsstrahlung for gold, tantalum, and tungsten bombarded by 5 MeV and 7.5 MeV electron beams. (3) Concrete attenuation calculations in several photon emission angles for the 5 MeV and 7.5 MeV electron beams bombarding a tantalum target. Based on the simulation, we calculated the expected increase in dose rate for facilities intending to increase the energy from 5 MeV to 7.5 MeV, and the concrete width needed to be added in order to keep the existing dose rate unchanged.

  13. Temperature and 8 MeV electron irradiation effects on GaAs solar cells

    Indian Academy of Sciences (India)

    Asha Rao; Sheeja Krishnan; Ganesh Sajeev; K Siddappa

    2010-06-01

    GaAs solar cells hold the record for the highest single band-gap cell efficiency. Successful application of these cells in advanced space-borne systems demand characterization of cell properties like dark current under different ambient conditions and the stability of the cells against particle irradiation in space. In this paper, the results of the studies carried out on the effect of 8 MeV electron irradiation on the electrical properties of GaAs solar cells are presented. The – (current–voltage) characteristics of the cells under dark and AM1.5 illumination condition are studied and 8 MeV electron irradiation was carried out on the cells where they were exposed to graded doses of electrons from 1 to 100 kGy. The devices were also characterized using capacitance measurements at various frequencies before and after irradiation. The effect of electron irradiation on the solar cell parameters was studied. It is found that only small changes were observed in the GaAs solar cell parameters up to an electron dose of 100 kGy, exhibiting good tolerance for electrons of 8 MeV energy.

  14. ElectroOptical measurements of ultrashort 45 MeV electron beam bunch

    CERN Document Server

    Nikas, D; Kowalski, L A; Larsen, R; Lazarus, D M; Ozben, C; Semertzidis, Y K; Tsang, Thomas; Srinivasan-Rao, T

    2001-01-01

    We have made an observation of 45 MeV electron beam bunches using the nondestructive electro-optical (EO) technique. The amplitude of the EO modulation was found to increase linearly with electron beam charge and decrease inversely with the optical beam path distance from the electron beam. The risetime of the signal was bandwidth limited by our detection system to \\~70ps. An EO signal due to ionization caused by the electrons traversing the EO crystal was also observed. The EO technique may be ideal for the measurement of bunch structure with femtosecond resolution of relativistic charged particle beam bunches.

  15. Determining the Effects of EMIC Waves on Precipitating MeV Electrons during Strom Main Phases

    Science.gov (United States)

    Chen, Y.

    2015-12-01

    Theoretic studies have suggested that electromagnetic ion cyclotron (EMIC) waves can cause significant precipitation of ~MeV electrons, supposedly accounting for the fast dropouts of outer-belt electrons during storm main phases. Usually the resonance between left-hand polarized EMIC with electrons with moderate energy is unlikely due to their opposite polarizations, while resonance with highly relativistic electrons do occur and cause electrons to precipitate into the atmosphere through pitch-angle scattering. Several previous studies on observations find a close relation between the two phenomena, e.g., Cliverd et al. [2007], Sandanger et al. [2007], and Miyoshi et al. [2008], while others find otherwise, e.g., Meredith et al. [2011]; recently, more observational evidence supporting the connection has been reported (e.g., Li et al. [2014] and Blum et al. [2015]). However, whether and under what favoring conditions EMIC waves cause rapid dropouts of relativistic electrons during storm main phases remain unresolved questions. Here, using latest wave and electron data from multiple missions including Van Allen Probes, BARREL, and NOAA POES, we systemically examine the relation between EMIC waves and MeV electron precipitation. We first construct two independent event lists for intensified EMIC waves and enhancements of MeV electron precipitation, respectively. Then we cross check the two lists to identify if any significant correlation exists in between, and further characterize the wave effectiveness in terms of L-shell, MLT, resonance energy, as well as the background plasma conditions. Results from this study will advance our knowledge about the loss mechanism of outer-belt electrons, thus laying down another stepping stone towards high-fidelity physics-based models for radiation belts.

  16. Radiation Damage of F8 Lead Glass with 20 MeV Electrons

    CERN Document Server

    Schaefer, B D; McChesney, P; Shepherd, M R; Frye, J M

    2011-01-01

    Using a 20 MeV linear accelerator, we investigate the effects of electromagnetic radiation on the optical transparency of F8 lead glass. Specifically, we measure the change in attenuation length as a function of radiation dose. Comparing our results to similar work that utilized a proton beam, we conclude that F8 lead glass is more susceptible to proton damage than electron damage.

  17. Radiation damage of F8 lead glass with 20 MeV electrons

    Science.gov (United States)

    Schaefer, B. D.; Mitchell, R. E.; McChesney, P.; Shepherd, M. R.; Frye, J. M.

    2012-03-01

    Using a 20 MeV linear accelerator, we investigate the effects of electromagnetic radiation on the optical transparency of F8 lead glass. Specifically, we measure the change in attenuation length as a function of radiation dose. Comparing our results to similar work that utilized a proton beam, we conclude that F8 lead glass is more susceptible to proton damage than electron damage.

  18. Cavity Formation in Aluminium Irradiated with a Pulsating Beam of 225 MeV Electrons

    DEFF Research Database (Denmark)

    Singh, Bachu Narain; Bilde-Sørensen, Jørgen; Leffers, Torben

    1984-01-01

    High-purity aluminium was irradiated with a pulsating beam of 225 MeV electrons to a maximum dose of 0.035 dpa with a helium generation rate of up to 17 appm/dpa. The irradiated samples contained cavities in the size range 5 to 70 nm. In a zone of up to 14 μm from the grain boundaries cavity size...

  19. The source of multi spectral energy of solar energetic electron

    Energy Technology Data Exchange (ETDEWEB)

    Herdiwijaya, Dhani [Astronomy Division and Bosscha Observatory, Faculty Mathematics and Natural Sciences, Intitute Technology of Bandung, Ganesha 10, Bandung, Indonesia 40132 dhani@as.itb.ac.id (Indonesia)

    2015-04-16

    We study the solar energetic electron distribution obtained from ACE and GOES satellites which have different altitudes and electron spectral energy during the year 1997 to 2011. The electron spectral energies were 0.038–0.315 MeV from EPAM instrument onboard ACE satellite and >2 MeV from GOES satellite. We found that the low electron energy has no correlation with high energy. In spite of we have corrected to the altitude differences. It implied that they originated from time dependent events with different sources and physical processes at the solar atmosphere. The sources of multi spectral energetic electron were related to flare and CME phenomena. However, we also found that high energetic electron comes from coronal hole.

  20. New applications of 10 MeV electrons for reeled goods

    Science.gov (United States)

    Günthard, C.; Lee, D. W.

    2000-03-01

    Because of their high penetration capability, electron beams produced by 10 MeV machines are increasingly used for the sterilization processing of medical devices. Worldwide there are already more than 20 such machines in action for this purpose. But compared with electron beam sterilization, the physical crosslinking of plastic products with 10 MeV has not been as much investigated as in the range of low and medium energy. So the products with high wall thickness or big dimensions are still chemically crosslinked as the penetration and power of the beam of existing accelerators was not sufficient for those products. But now radiation crosslinking is possible also for higher dimensions of reeled goods due to higher beam power up to 150 kW, and one machine with different handling systems can be used for sterilization and modification of plastic products. The aim of our work is to examine the homogeneous crosslinking of industrial products by a 10 MeV/150 kW electron beam as for instance for XLPE-c pipes and heat shrinkable tubes. Furthermore the uniformity of crosslinking especially along the roundness is measured, which is one of the essential quality characteristics.

  1. The MAMI source of polarized electrons

    Energy Technology Data Exchange (ETDEWEB)

    Aulenbacher, K. [Johannes Gutenberg Univ., Mainz (Germany). Inst. fur Kernphys.; Nachtigall, C.; Andresen, H.G.; Bermuth, J.; Dombo, T.; Drescher, P.; Euteneuer, H.; Fischer, H.; Harrach, D. v.; Hartmann, P.; Hoffmann, J.; Jennewein, P.; Kaiser, K.H.; Koebis, S.; Kreidel, H.J.; Langbein, J.; Petri, M.; Pluetzer, S.; Reichert, E.; Schemies, M.; Schoepe, H.-J.; Steffens, K.-H.; Steigerwald, M.; Trautner, H.; Weis, T.

    1997-06-11

    The present work describes the source of polarized electrons that is run at the 855 MeV race track microtron MAMI at the Johannes Gutenberg Universitaet in Mainz. The source is based on photoelectron emission from (III-V)-semiconductors. Presently strained layer InGaP- or GaAsP-cathodes are used, which are processed to negative electron affinity by coverage of the surface with a submonolayer of caesium and oxygen. Electron beams spin-polarized up to a degree of P=55% at a quantum efficiency of QE=2% or P=75% at QE=0.4%, respectively, are obtained. The well-known but hitherto unsolved problem of limited cathode lifetime has been sidestepped by the attachment of an UHV load lock system to the source electron gun. It allows quick replacement of cathodes without breaking the gun vacuum. Availabilities in excess of 85% are obtained regularly in beamtimes longer than 100 h. The source was mainly applied in measurements of nucleon form factors via the reactions {sup 1}H(vector e,e` vector p), {sup 2}D(vector e,e` vector p), {sup 2}D(vector e,e` vector n), and {sup 3} vector He(vector e,e`n). More than 1600 h beamtime have been accomplished in physics experiments with polarized electron beams at MAMI up to now. (orig.).

  2. Electron Accelerator Shielding Design of KIPT Neutron Source Facility

    OpenAIRE

    Zhaopeng Zhong; Yousry Gohar

    2016-01-01

    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 nu...

  3. Study on the microwave ion source of 100-MeV proton linac

    CERN Document Server

    Kwon, Hyeok-Jung

    2016-01-01

    A microwave ion source is used as an ion source of 100-MeV proton accelerator at Korea Multipurpose Accelerator Complex (KOMAC). The specifications of the ion source are 50 keV in energy and 20 mA in peak current. The plasma is operated in CW mode using magnetron and the pulse beam is extracted using semiconductor switch located in the extraction power supply. The beam characteristics were measured based on the pulse voltage and current. A test stand was also installed to study the beam characteristics of the ion source in off-line. In this paper, the pulse beam characteristics of the ion source are presented and the installation of the test stand is reported.

  4. 'Cabinet-safe' study of 1-8 MeV electron accelerators

    CERN Document Server

    Wells, D P; Yoon, W Y; Harmon, F

    2001-01-01

    The development of 'cabinet-safe' accelerator technology for approx 1-8 MeV electron LINACs would remove the only major barrier to large-scale 'field' applications of these accelerators. These applications range from non-destructive evaluation and assay to radiolytic degradation of hazardous waste. All field applications require large forward dose and very little lateral dose. We investigated the origin, energy, and angular distribution of unwanted lateral radiation dose from two different electron LINACS at three energies. We report on the contributions of various beam parameters to unwanted radiation dose and propose methods to control key beam parameters that significantly contribute to these doses.

  5. Identification of defects in GaAs induced by 1 MeV electron irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Lai, S.T.; Nener, B.D.; Faraone, L.; Nassibian, A.G. [Western Australia Univ., Nedlands, WA (Australia); Hotchkis, M.A.C. [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia)

    1993-12-31

    This paper shows that 1 MeV electron irradiation on n-type vapor phase epitaxial (VPE) GaAs creates three electron traps E1, E2 and EL6, and results in the splitting of the EL2 center into two levels EL2-A and EL2-B. A 15 minutes isochronal anneal results in the annihilation of the E1 and E2 traps, a reduction in EL6 trap concentration, and the return of EL2 to a single level EL2-A. A defect model is outlined which correlates with the observed results. 4 refs., 2 tabs., 3 figs.

  6. Solar Modulation of 50-500 Mev Cosmic Ray Electrons and the Electron Spectrum from 1964-1994

    Science.gov (United States)

    Huber, David M.

    1998-11-01

    Cosmic ray electrons have been directly measured since 1960. Over the last four decades a wealth of data has been collected on these particles, but perhaps none as valuable as the measurements made by the University of Chicago MEH experiment on the ISEE-3/ICE spacecraft and the University of Chicago/Bartol Research Institute Low Energy Electron (LEE) balloon experiment. These data span parts of four solar cycles and cover three solar polarity reversals. The MEH dataset itself has continuous electron coverage spanning seventeen years and two polarity reversals. A new analysis has been done on the MEH dataset to determine the spectrum of electrons with energies from about 30 to 500 MeV and interpret the evolution of the spectrum in the context of the modulation of cosmic electrons over the last four solar cycles. The spectral index for electrons between 30 and 500 MeV was observed to be at all times negative between the years 1979 and 1994. This observation supports recent theoretical calculations that predict fundamental differences between the behavior of electrons and protons at low energies, namely that electrons have a much longer mean free path at low energies than previously assumed. Recent modulation calculations have focused attention on the A-positive solar polarity state, but the compilation of electron spectrum observations and calculations in this work provides a basis for future exploration of the A-negative solar cycle.

  7. X-ray observations of MeV electron precipitation with a balloon-borne germanium spectrometer

    Science.gov (United States)

    Millan, R. M.; Lin, R. P.; Smith, D. M.; Lorentzen, K. R.; McCarthy, M. P.

    2002-12-01

    The high-resolution germanium detector aboard the MAXIS (MeV Auroral X-ray Imaging and Spectroscopy) balloon payload detected nine X-ray bursts with significant flux extending above 0.5 MeV during an 18 day flight over Antarctica. These minutes-to-hours-long events are characterized by an extremely flat spectrum (~E-2) similar to the first MeV event discovered in 1996, indicating that the bulk of parent precipitating electrons is at relativistic energies. The MeV bursts were detected between magnetic latitudes 58°-68° (L-values of 3.8-6.7) but only in the late afternoon/dusk sectors (14:30-00:00 MLT), suggesting scattering by EMIC (electromagnetic ion cyclotron) waves as a precipitation mechanism. We estimate the average flux of precipitating E >= 0.5 MeV electrons to be ~360 cm-2s-1, corresponding to about 5 × 1025 such electrons precipitated during the eight days at L = 3.8-6.7, compared to ~2 × 1025 trapped 0.5-3.6 MeV electrons estimated from dosimeter measurements on a GPS spacecraft. These observations show that MeV electron precipitation events are a primary loss mechanism for outer zone relativistic electrons.

  8. Proposal to observe half-bare electrons on a 45-MeV linac

    Science.gov (United States)

    Trofymenko, S. V.; Shul'ga, N. F.; Delerue, N.; Jenzer, S.; Khodnevych, V.; Migayron, A.

    2017-07-01

    The experimental investigation of the transition radiation (TR) generated by a “half-bare” electron having the proper field different from the Coulomb one is proposed. The electrons in half-bare state are intended to be obtained in the result of their crossing of a conducting screen. We propose to investigate the influence of the half-bare state of electron in this process upon TR generated by such electron on a downstream OTR screen situated on some distance along the direction of the electron beam from the upstream screen which “undresses” the particle. Calculations are presented for the case of a 45 MeV linac and the distance between the screens in the region between 100 mm and 300 mm. The proposed experiment is expected to reveal new features of TR signal in such process comparing to previous measurements.

  9. Electro-optical Measurements of Ultrashort 45 MeV Electron Beam Bunches

    CERN Document Server

    Tsang, Thomas; Kowalski, L A; Larsen, R; Lazarus, D M; Nikas, D; Ozben, C; Semertzidis, Y K; Srinivasan-Rao, T

    2000-01-01

    We have measured the temporal duration of 45 MeV picosecond electron beam bunches using a noninvasive electro-optical (EO) technique. The amplitude of the EO modulation was found to increase linearly with electron beam charge and decrease inversely with distance from the electron beam. The risetime of the temporal signal was limited by our detection system to ~70ps. The EO signal due to ionization caused by the electrons traversing the EO crystal was also observed. It has a distinctively long decay time constant and signal polarity opposite to that due to the field induced by the electron beam. The electro-optical technique may be ideal for the measurement of bunch length of femtosecond, relativistic, high energy, charged, particle beams.

  10. Attenuation of 10 MeV electron beam energy to achieve low doses does not affect Salmonella spp. inactivation kinetics

    Science.gov (United States)

    Hieke, Anne-Sophie Charlotte; Pillai, Suresh D.

    2015-05-01

    The effect of attenuating the energy of a 10 MeV electron beam on Salmonella inactivation kinetics was investigated. No statistically significant differences were observed between the D10 values of either Salmonella 4,[5],12:i:- or a Salmonella cocktail (S. 4,[5],12:i:-, Salmonella Heidelberg, Salmonella Newport, Salmonella Typhimurium, Salmonella) when irradiated with either a non-attenuated 10 MeV eBeam or an attenuated 10 MeV eBeam (~2.9±0.22 MeV). The results show that attenuating the energy of a 10 MeV eBeam to achieve low doses does not affect the inactivation kinetics of Salmonella spp. when compared to direct 10 MeV eBeam irradiation.

  11. Evaluation of induced radioactivity in 10 MeV electron-irradiated spices

    Energy Technology Data Exchange (ETDEWEB)

    Furuta, Masakazu; Ito, Norio; Mizohata, Akira; Matsunami, Tadao; Katayama, Tadashi; Toratani, Hirokazu (Osaka Prefectural Univ., Sakai (Japan). Research Inst. for Advanced Science and Technology); Takeda, Atsuhiko

    1993-10-01

    In order to make clear appreciation to induced radioactivity in the irradiated foods, photonuclear reactions which could produce radioactivity at energies up to 10 MeV were listed up from elemental compositions of black pepper, white pepper, red pepper, ginger and turmeric. The samples were irradiated with 10 MeV electron from a linear accelerator to a dose of 100 kGy and radioactivity was measured. Induced radioactivity could not be detected significantly by gamma-ray spectrometry and beta-ray counting in the irradiated samples except for spiked samples which contain some photonuclear target nuclides in the list. From the amount of observed radioactivities of short-lived photonuclear products in the spiked samples and calculation of H[sub 50] according to ICRP Publication 30, it was concluded that the induced radioactivity and its biological effects in the 10 MeV electron-irradiated natural samples were negligible in comparison with natural radioactivity from [sup 40]K contained in the samples. (J.P.N.).

  12. Dosimetric shield evaluation with tungsten sheet in 4, 6, and 9MeV electron beams.

    Science.gov (United States)

    Fujimoto, Takahiro; Monzen, Hajime; Nakata, Manabu; Okada, Takashi; Yano, Shinsuke; Takakura, Toru; Kuwahara, Junichi; Sasaki, Makoto; Higashimura, Kyoji; Hiraoka, Masahiro

    2014-11-01

    In electron radiotherapy, shielding material is required to attenuate beam and scatter. A newly introduced shielding material, tungsten functional paper (TFP), has been anticipated to become a very useful device that is lead-free, light, flexible, and easily processed, containing very fine tungsten powder at as much as 80% by weight. The purpose of this study was to investigate the dosimetric changes due to TFP shielding for electron beams. TFP (thickness 0-15mm) was placed on water or a water-equivalent phantom. Percentage depth ionization and transmission were measured for 4, 6, and 9MeV electron beams. Off-center ratio was also measured using film dosimetry at depth of dose maximum under similar conditions. Then, beam profiles and transmission with two shielding materials, TFP and lead, were evaluated. Reductions of 95% by using TFP at 0.5cm depth occurred at 4, 9, and 15mm with 4, 6, and 9MeV electron beams, respectively. It is found that the dose tend to increase at the field edge shaped with TFP, which might be influenced by the thickness. TFP has several unique features and is very promising as a useful tool for radiation protection for electron beams, among others.

  13. Prediction of MeV electron fluxes throughout the outer radiation belt using multivariate autoregressive models

    Science.gov (United States)

    Sakaguchi, Kaori; Nagatsuma, Tsutomu; Reeves, Geoffrey D.; Spence, Harlan E.

    2015-12-01

    The Van Allen radiation belts surrounding the Earth are filled with MeV-energy electrons. This region poses ionizing radiation risks for spacecraft that operate within it, including those in geostationary orbit (GEO) and medium Earth orbit. To provide alerts of electron flux enhancements, 16 prediction models of the electron log-flux variation throughout the equatorial outer radiation belt as a function of the McIlwain L parameter were developed using the multivariate autoregressive model and Kalman filter. Measurements of omnidirectional 2.3 MeV electron flux from the Van Allen Probes mission as well as >2 MeV electrons from the GOES 15 spacecraft were used as the predictors. Model explanatory parameters were selected from solar wind parameters, the electron log-flux at GEO, and geomagnetic indices. For the innermost region of the outer radiation belt, the electron flux is best predicted by using the Dst index as the sole input parameter. For the central to outermost regions, at L ≧ 4.8 and L ≧ 5.6, the electron flux is predicted most accurately by including also the solar wind velocity and then the dynamic pressure, respectively. The Dst index is the best overall single parameter for predicting at 3 ≦ L ≦ 6, while for the GEO flux prediction, the KP index is better than Dst. A test calculation demonstrates that the model successfully predicts the timing and location of the flux maximum as much as 2 days in advance and that the electron flux decreases faster with time at higher L values, both model features consistent with the actually observed behavior.

  14. Van Allen Probes observations of prompt MeV radiation belt electron acceleration in nonlinear interactions with VLF chorus

    Science.gov (United States)

    Foster, J. C.; Erickson, P. J.; Omura, Y.; Baker, D. N.; Kletzing, C. A.; Claudepierre, S. G.

    2017-01-01

    Prompt recovery of MeV (millions of electron Volts) electron populations in the poststorm core of the outer terrestrial radiation belt involves local acceleration of a seed population of energetic electrons in interactions with VLF chorus waves. Electron interactions during the generation of VLF rising tones are strongly nonlinear, such that a fraction of the relativistic electrons at resonant energies are trapped by waves, leading to significant nonadiabatic energy exchange. Through detailed examination of VLF chorus and electron fluxes observed by Van Allen Probes, we investigate the efficiency of nonlinear processes for acceleration of electrons to MeV energies. We find through subpacket analysis of chorus waveforms that electrons with initial energy of hundreds of keV to 3 MeV can be accelerated by 50 keV-200 keV in resonant interactions with a single VLF rising tone on a time scale of 10-100 ms.

  15. Calibration of imaging plates to electrons between 40 and 180 MeV.

    Science.gov (United States)

    Rabhi, N; Bohacek, K; Batani, D; Boutoux, G; Ducret, J-E; Guillaume, E; Jakubowska, K; Thaury, C; Thfoin, I

    2016-05-01

    This paper presents the response calibration of Imaging Plates (IPs) for electrons in the 40-180 MeV range using laser-accelerated electrons at Laboratoire d'Optique Appliquée (LOA), Palaiseau, France. In the calibration process, the energy spectrum and charge of electron beams are measured by an independent system composed of a magnetic spectrometer and a Lanex scintillator screen used as a calibrated reference detector. It is possible to insert IPs of different types or stacks of IPs in this spectrometer in order to detect dispersed electrons simultaneously. The response values are inferred from the signal on the IPs, due to an appropriate charge calibration of the reference detector. The effect of thin layers of tungsten in front and/or behind IPs is studied in detail. GEANT4 simulations are used in order to analyze our measurements.

  16. Scalability of the LEU-Modified Cintichem Process: 3-MeV Van de Graaff and 35-MeV Electron Linear Accelerator Studies

    Energy Technology Data Exchange (ETDEWEB)

    Rotsch, David A. [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division; Brossard, Tom [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division; Roussin, Ethan [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division; Quigley, Kevin [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division; Chemerisov, Sergey [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division; Gromov, Roman [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division; Jonah, Charles [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division; Hafenrichter, Lohman [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division; Tkac, Peter [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division; Krebs, John [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division; Vandegrift, George F. [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division

    2016-10-31

    Molybdenum-99, the mother of Tc-99m, can be produced from fission of U-235 in nuclear reactors and purified from fission products by the Cintichem process, later modified for low-enriched uranium (LEU) targets. The key step in this process is the precipitation of Mo with α-benzoin oxime (ABO). The stability of this complex to radiation has been examined. Molybdenum-ABO was irradiated with 3 MeV electrons produced by a Van de Graaff generator and 35 MeV electrons produced by a 50 MeV/25 kW electron linear accelerator. Dose equivalents of 1.7–31.2 kCi of Mo-99 were administered to freshly prepared Mo-ABO. Irradiated samples of Mo-ABO were processed according to the LEU Modified-Cintichem process. The Van de Graaff data indicated good radiation stability of the Mo-ABO complex up to ~15 kCi dose equivalents of Mo-99 and nearly complete destruction at doses >24 kCi Mo-99. The linear accelerator data indicate that even at 6.2 kCi of Mo-99 equivalence of dose, the sample lost ~20% of Mo-99. The 20% loss of Mo-99 at this low dose may be attributed to thermal decomposition of the product from the heat deposited in the sample during irradiation.

  17. Relativistic electron microbursts and variations in trapped MeV electron fluxes during the 8-9 October 2012 storm: SAMPEX and Van Allen Probes observations

    Science.gov (United States)

    Kurita, Satoshi; Miyoshi, Yoshizumi; Blake, J. Bernard; Reeves, Geoffery D.; Kletzing, Craig A.

    2016-04-01

    It has been suggested that whistler mode chorus is responsible for both acceleration of MeV electrons and relativistic electron microbursts through resonant wave-particle interactions. Relativistic electron microbursts have been considered as an important loss mechanism of radiation belt electrons. Here we report on the observations of relativistic electron microbursts and flux variations of trapped MeV electrons during the 8-9 October 2012 storm, using the SAMPEX and Van Allen Probes satellites. Observations by the satellites show that relativistic electron microbursts correlate well with the rapid enhancement of trapped MeV electron fluxes by chorus wave-particle interactions, indicating that acceleration by chorus is much more efficient than losses by microbursts during the storm. It is also revealed that the strong chorus wave activity without relativistic electron microbursts does not lead to significant flux variations of relativistic electrons. Thus, effective acceleration of relativistic electrons is caused by chorus that can cause relativistic electron microbursts.

  18. The Gent University 15 MeV high-current linear electron accelerator facility

    Science.gov (United States)

    Mondelaers, W.; Van Laere, K.; Goedefroot, A.; Van den Bossche, K.

    1996-01-01

    The Gent University 15 MeV 20kW linear electron accelerator facility was initially designed for fundamental nuclear physics research. During the last years a large effort has been devoted to the expansion of the range of machine applications in view of a new extensive experimental programme in the fields of atomic and solid-state physics, biomaterials research, polymer chemistry, space research, food technology, high-dose dosimetry and radiation therapy. The accelerator facility in its present configuration, the peripheral equipment and the experimental programme are described with emphasis on the original features.

  19. Scale size of magnetic turbulence in tokamaks probed with 30-MeV electrons

    Science.gov (United States)

    Entrop; Lopes Cardozo NJ; Jaspers; Finken

    2000-04-17

    Measurements of synchrotron radiation emitted by 30-MeV runaway electrons in the TEXTOR-94 tokamak show that the runaway population decays after switching on neutral beam injection (NBI). The decay starts only with a significant delay, which decreases with increasing NBI heating power. This delay provides direct evidence of the energy dependence of runaway confinement, which is expected if magnetic modes govern the loss of runaways. Application of the theory by Mynick and Strachan [Phys. Fluids 24, 695 (1981)] yields estimates for the "mode width" (delta) of magnetic perturbations: delta<0.5 cm in Ohmic discharges, increasing to delta = 4.4 cm for 0. 6 MW NBI.

  20. Bunch evolution study in optimization of MeV ultrafast electron diffraction

    CERN Document Server

    Lu, Xianhai; Huang, Wenhui; Tang, Chuanxiang

    2014-01-01

    Megaelectronvolt ultrafast electron diffraction (UED) is a promising detection tool for ultrafast processes. The quality of diffraction image is determined by the transverse evolution of the probe bunch. In this paper, we study the contributing terms of the emittance and space charge effects to the bunch evolution in MeV UED scheme, employing a mean-field model with an ellipsoidal distribution as well as particle tracking simulation. Small transverse dimension of the drive laser is found critical to improve the reciprocal resolution, exploiting both smaller emittance and larger transverse bunch size before the solenoid. The degradation of reciprocal spatial resolution caused by the space charge effects should be carefully controlled.

  1. Toward 10 meV electron energy-loss spectroscopy resolution for plasmonics.

    Science.gov (United States)

    Bellido, Edson P; Rossouw, David; Botton, Gianluigi A

    2014-06-01

    Energy resolution is one of the most important parameters in electron energy-loss spectroscopy. This is especially true for measurement of surface plasmon resonances, where high-energy resolution is crucial for resolving individual resonance peaks, in particular close to the zero-loss peak. In this work, we improve the energy resolution of electron energy-loss spectra of surface plasmon resonances, acquired with a monochromated beam in a scanning transmission electron microscope, by the use of the Richardson-Lucy deconvolution algorithm. We test the performance of the algorithm in a simulated spectrum and then apply it to experimental energy-loss spectra of a lithographically patterned silver nanorod. By reduction of the point spread function of the spectrum, we are able to identify low-energy surface plasmon peaks in spectra, more localized features, and higher contrast in surface plasmon energy-filtered maps. Thanks to the combination of a monochromated beam and the Richardson-Lucy algorithm, we improve the effective resolution down to 30 meV, and evidence of success up to 10 meV resolution for losses below 1 eV. We also propose, implement, and test two methods to limit the number of iterations in the algorithm. The first method is based on noise measurement and analysis, while in the second we monitor the change of slope in the deconvolved spectrum.

  2. Synthesis and characterisation of starch grafted superabsorbent via 10 MeV electron-beam irradiation.

    Science.gov (United States)

    Zhang, Sufen; Wang, Wei; Wang, Haiyan; Qi, Wenyuan; Yue, Ling; Ye, Qingfu

    2014-01-30

    A starch-graft-polyacrylamide (St-g-PAM) superabsorbent crosslinked by N,N'-methyl bisacrylamide (MBA) was prepared using 10 MeV simultaneous electron beam irradiation at room temperature and subsequent alkaline hydrolysis. The effects of the irradiation dose, acryliamide-to-anhydroglucose unit (AM-to-AGU) ratio and crosslinker amount on the properties of the obtained polymers were evaluated. The structure of the graft copolymer was confirmed by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscope (SEM). Optimisation treatments were carried out and found for a total dose of 8 kGy, an AM-to-AGU ratio of 4.5 mol mol(-1) and a crosslinker-to-AM ratio of 0.4%mol mol(-1). The obtained superabsorbent polymer showed the maximum absorptions of 1,452 gg(-1) and 83 gg(-1) for distilled water and saline solution, respectively (relative to its own dry weight). The results suggest 10 MeV electron beam irradiation is more efficient than γ-ray irradiation due to its higher energy and dose rate.

  3. 500-MeV electron beam bench-mark experiments and calculations

    Energy Technology Data Exchange (ETDEWEB)

    Farley, E.; Crase, K.; Selway, D.

    1979-12-01

    Experiments measuring the energy deposited by electron beams were performed to provide bench marks against which to evaluate our HANDYL76 electron beam computer code. The experiments, done at Stanford's Mk III accelerator, measured dose vs depth and dose vs radius profiles induced in layered aluminum targets by 500-MeV electrons. The dose was measured by passive thermoluminescence and photographic film placed between aluminum plates. The calculations predict a dose vs radius profile that forward-peaks on axis after the beam passes through a 200-cm air gap; the experimental measurements do not show this peak. This discrepancy indicates there may be a problem in using HANDYL76 to calculate deep penetration of a target with a large gap.

  4. Photocatalytic activity of 6.5 MeV electron-irradiated ZnO nanorods

    Science.gov (United States)

    Sapnar, K. B.; Ghule, L. A.; Bhoraskar, S. V.; Garadkar, K. M.; Dhole, S. D.; Bhoraskar, V. N.

    2012-04-01

    The microwave-synthesized zinc-oxide (ZnO) nanonorods of average length of ∼ 1500 nm and diameter ∼ 100 nm were irradiated with 6.5 meV electrons. From sample to sample, the electron fluence was varied over the range 5×1014 to 2.5×1015 e-cm-2. The pre- and post-electron-irradiated ZnO nanorods were characterized by X-ray diffraction, UV-VIS, EDAX, scanning electron microscopy, transmission electron microscopy, and BET methods. The results show that after electron irradiation, the ZnO nanorods could retain the hexagonal phase with the wurtzite structure; however, the average length of the ZnO nanorods reduced to ∼ 800 nm. Moreover, the oxygen atoms from a fraction of ZnO molecules were dislodged, and the process contributed to the formation of Zn-ZnO mixed phase, with increased zinc to oxygen ratio. In the photo-degradation of Rhodamine-B, a significant enhancement in the photocatalytic activity of the electron-irradiated ZnO nanorods was observed. This could be attributed to the induced defects, reduced dimensions, and increased surface area of the ZnO nanorods, in addition to the formation of the Zn-ZnO phase. All these could collectively contribute to the effective separation of the photogenerated electrons from the holes on the ZnO nanorods, and therefore enhance the photocatalytic activity under UV exposure.

  5. Design status of an intense 14 MeV neutron source for cancer therapy

    CERN Document Server

    Yao, Z E; Cheng, S W; Jia, W B

    2002-01-01

    Design and development of an intense 14 MeV neutron source for cancer therapy is in progress at the Institute of Nuclear Research of Lanzhou University. The neutrons from the T(d,n) sup 4 He reaction are produced by bombarding a rotating titanium tritide target with a 40 mA deuteron beam at 600 keV. The designed neutron yield is 8x10 sup 1 sup 2 n/s and the maximum dose rate at a 100 cm source-to-skin distance is 25 cGy/min. The HV terminal, accelerating column and HV power supply are enclosed inside a stainless steel pressure vessel containing 6 atm SF sub 6 gas to provide the electrical insulation.

  6. INTEGRAL/XMM views on the MeV source GRO J1411-64

    CERN Document Server

    Torres, D F; Reimer, O; Barcons, X; Corral, A; Bosch-Ramon, V; Paredes, J M; Romero, G E; Qu, J L; Collmar, W; Schönfelder, V; Butt, Y; Torres, Diego F.; Zhang, Shu; Reimer, Olaf; Barcons, Xavier; Corral, Amalia; Bosch-Ramon, Valent\\'{\\i}; Paredes, Josep M.; Romero, Gustavo E.; Qu, Jin Lu; Collmar, Werner; Sch\\"onfelder, Volker; Butt, Yousaf

    2006-01-01

    The COMPTEL unidentified source GRO J 1411-64 was observed by INTEGRAL and XMM-Newton in 2005. The Circinus Galaxy is the only source detected within the 4$\\sigma$ location error of GRO J1411-64, but in here excluded as the possible counterpart. At soft X-rays, 22 reliable and statistically significant sources (likelihood $> 10$) were extracted and analyzed from XMM-Newton data. Only one of these sources, XMMU J141255.6 -635932, is spectrally compatible with GRO J1411-64 although the fact the soft X-ray observations do not cover the full extent of the COMPTEL source position uncertainty make an association hard to quantify and thus risky. At the best location of the source, detections at hard X-rays show only upper limits, which, together with MeV results obtained by COMPTEL suggest the existence of a peak in power output located somewhere between 300-700 keV for the so-called low state. Such a spectrum resembles those in blazars or microquasars, and might suggest at work by a similar scenario. However, an an...

  7. Physical and thermal properties of 8 MeV electron beam irradiated HPMC polymer films

    Energy Technology Data Exchange (ETDEWEB)

    Sangappa [Department of Studies in Physics, Mangalore University, Mangalagangotri 574 199 (India)], E-mail: sangappa@mangaloreuniversity.ac.in; Demappa, T.; Mahadevaiah [Department of Polymer Science, Sir M V, P G Center, University of Mysore, Mandya 575 007 (India); Ganesha, S. [Microtron Center, Mangalore University, Mangalagangotri 574 199 (India); Divakara, S. [Department of Physics, East Point College of Engineering and Technology, Bangalore 560049 (India); Pattabi, Manjunath [Department of Material Science, Mangalore University, Mangalagangotri 574 199 (India); Somashekar, R. [Department of Studies in Physics, University of Mysore, Manasagangotri, Mysore 570 006 (India)

    2008-09-15

    Microstructural modification in hydroxypropyl methylcellulose (HPMC) polymer films induced by electron irradiation is studied. Irradiation was performed in air at room temperature using a 8 MeV electron accelerator at doses of 25, 50, 75 and 100 kGy. Irradiation can be used to crosslink or degrade the desired component or to fix the polymer morphology. Changes in microstructural parameters, crystallinity and thermal properties in virgin and irradiated HPMC films have been studied using wide angle X-ray scattering data and differential scanning calorimetry. The heat of fusion and the degree of crystallinity are found to be highest for unirradiated HPMC and the crystallite size is larger in virgin HPMC films.

  8. Capacitance and conductance studies on silicon solar cells subjected to 8 MeV electron irradiations

    Science.gov (United States)

    Sathyanarayana Bhat, P.; Rao, Asha; Sanjeev, Ganesh; Usha, G.; Priya, G. Krishna; Sankaran, M.; Puthanveettil, Suresh E.

    2015-06-01

    The space grade silicon solar cells were irradiated with 8 MeV electrons with doses ranging from 5-100 k Gy. Capacitance and conductance measurements were carried out in order to investigate the anomalous degradation of the cells in the radiation harsh environments and the results are presented in this paper. Detailed and systematic analysis of the frequency-dependent capacitance and conductance measurements were performed to extract the information about the interface trap states. The small increase in density of interface states was observed from the conductance-frequency measurements. The reduction in carrier concentration upon electron irradiation is due to the trapping of charge carriers by the radiation induced trap centres. The Drive Level Capacitance Profiling (DLCP) technique has been applied to study the properties of defects in silicon solar cells. A small variation in responding state densities with measuring frequency was observed and the defect densities are in the range 1015 -1016 cm-3.

  9. Vacuum system of the 3MeV industrial electron beam accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Jayaprakash, D; Mishra, R L; Ghodke, S R; Kumar, M; Kumar, M; Nanu, K; Mittal, Dr K C [Accelerator and Pulse Power Division, Bhabha Atomic Research Centre, Trombay, Mumbai, 400 085 (India)], E-mail: jaypee@barc.gov.in

    2008-05-01

    One DC Accelerator, for electron beam of 3 MeV energy and 10 mA beam current, to derive 30 KW beam power for Industrial applications is nearing completion at Electron Beam Centre, Kharghar, Navi Mumbai. Beam-line of the accelerator is six meters long, consists of electron gun at top, followed by the accelerating column and finally the scan horn. Electron gun and the accelerating column is exposed to SF{sub 6} gas at six atmospheres. Area exposed to the vacuum is 65,000 sq: cm, and includes a volume of 200 litres. Vacuum of the order of 1x10{sup -7}mbar is desired. To ensure a good vacuum gradient, distributive pumping is implemented. Electron beam is scanned to a size of 5cm x 120cm, to get a useful beam coverage, for industrial radiation applications. The beam is extracted through a window of Titanium foil of 50{mu}m thickness. A safety interlock, to protect the electron gun, accelerating column and sputter ion pumps, in case of a foil rupture, is incorporated. Foil change can be done without disturbing the vacuum in the other zones. System will be integrated to a master control system to take care of the various safety aspects, and to make it operator friendly.

  10. Vacuum system of the 3MeV industrial electron beam accelerator

    Science.gov (United States)

    Jayaprakash, D.; Mishra, R. L.; Ghodke, S. R.; kumar, M.; kumar, M.; Nanu, K.; Mittal, K. C., Dr

    2008-05-01

    One DC Accelerator, for electron beam of 3 MeV energy and 10 mA beam current, to derive 30 KW beam power for Industrial applications is nearing completion at Electron Beam Centre, Kharghar, Navi Mumbai. Beam-line of the accelerator is six meters long, consists of electron gun at top, followed by the accelerating column and finally the scan horn. Electron gun and the accelerating column is exposed to SF6 gas at six atmospheres. Area exposed to the vacuum is 65,000 sq: cm, and includes a volume of 200 litres. Vacuum of the order of 1×10-7mbar is desired. To ensure a good vacuum gradient, distributive pumping is implemented. Electron beam is scanned to a size of 5cm × 120cm, to get a useful beam coverage, for industrial radiation applications. The beam is extracted through a window of Titanium foil of 50μm thickness. A safety interlock, to protect the electron gun, accelerating column and sputter ion pumps, in case of a foil rupture, is incorporated. Foil change can be done without disturbing the vacuum in the other zones. System will be integrated to a master control system to take care of the various safety aspects, and to make it operator friendly.

  11. ICPP: Scale size of of magnetic turbulence as probed with 30 MeV runaway electrons

    Science.gov (United States)

    Jaspers, Roger

    2000-10-01

    This paper reviews results concerning generation, confinement and transport of runaway electrons in the energy range 20-30 MeV in the TEXTOR tokamak. For future fusion reactors, it is of major importance to know the processes of runaway generation and runaway loss after disruptions, because of the potential damage to first wall components. Second, since the runaway electrons are effectively collisionless, their confinement is determined by the magnetic field turbulence. In this way the runaway transport provides a unique opportunity to probe turbulence in the core of a thermonuclear plasma. Runaway electrons above 20 MeV emit synchrotron radiation in the (near) infrared, which can easily be detected by thermographic cameras. This technique is developed and exploited at the TEXTOR-94 tokamak and has resulted in some spectacular results. These include: the experimental evidence of the secondary (`knock-on') runaway generation; the discovery of the runaway snake; the observation of disruption generated runaways; the probing of magnetic turbulence in the core of the plasma in Ohmic and additionally heated plasmas. The paper reviews these results with special emphasis on the subject of probing magnetic turbulence in the core of the plasma. Measurements in the TEXTOR-94 tokamak show that after switching on Neutral Beam Injection, the runaway population decays. The decay only starts with a significant delay, which decreases with increasing NBI heating power. This delay provides direct evidence of the energy dependence of runaway confinement, which is expected if magnetic modes govern the loss of runaway electrons. These observations allow to estimate the mode width δ of the magnetic perturbations:δ smaller than 0.5 cm in Ohmic discharges, increasing to δ=3D 4.4 cm for 0.6 MW NBI power.

  12. Experimental SF6/-//SF6 and Cl/-//CFC13 electron-attachment cross sections in the energy range 0-200 meV

    Science.gov (United States)

    Chutjian, A.

    1981-01-01

    Experimental cross sections for the electron-attachment processes for SF6(-)/SF6 and Cl(-)/CFl3 are reported in the energy range 0-200 meV by normalizing each attachment line shape to measurement of a thermal rate coefficient. When the same ion states are detected, good agreement is found between present values, for which a monoenergetic electron source is used, and swarm-unfolded results. The present data constitute a new limit for cross sections reported at high resolution at the lowest electron energy.

  13. Near realtime forecasting of MeV protons on the basis of sub relativistic electrons

    Science.gov (United States)

    Labrenz, Johannes; Heber, Bernd; Kuehl, Patrick; Sarlanis, Christos; Malandraki, Olga; Posner, Arik

    2016-04-01

    A major impact on human and robotic space exploration activities is the sudden and prompt occurrence of solar energetic ion events. In order to provide up to an hour warning before these particles arrive at Earth, relativistic electron and below 50 MeV proton data from the Electron Proton Helium Instrument (EPHIN) on SOHO were used to implement the 'Relativistic Electron Alert System for Exploration (REleASE)'. It has been demonstrated that the analysis of relativistic electron time profiles provides a low miss and false alarm rate. High Energy Solar Particle Events foRecastIng and Analysis (HESPERIA) is a project funded within the European Union's Horizon 2020 research and innovation programme (PROTEC-1-2014 Call: Space Weather). Within this project the REleASE forecasting scheme was rewritten in the open access programming language PYTHON and will be made public. As a next step, we have analyzed the possibility to also use, along with relativistic electrons (v > 0.9 c) provided by SOHO, near-relativistic (v forecasting scheme to provide reliable SEP forecasts. A comparison of measured and forecast proton intensities by SOHO/EPHIN and ACE/EPAM will be presented. In addition we investigated the false alarm rate and detection probability of solar ion events. This project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 637324.

  14. Central region design for a 10 MeV internal ion source cyclotron

    Institute of Scientific and Technical Information of China (English)

    QIN Bin; LIU Kai-Feng; FENG Yi-Zhang; FAN Ming-Wu

    2009-01-01

    Internal ion sources are widely adopted in commercial cyclotrons used for short-life isotopes produc-tion. Without beam manipulation provided by the external beam injection line, the central region of this type of cyclotron is more sensitive and should be carefully designed. A design study and beam dynamics simulation for the central region of a 10 MeV compact cyclotron is presented. The OPERA3D/TOSCA code was used to calculate the electric field from a parameterized three dimensional (3D) central region model. With iterative structure optimizations of the central region, the beam centering and vertical focusing is well controlled, and the RF phase acceptance is around 25° A c++ code for beam simulation in the central region was developed and tested.

  15. A Project for High Fluence 14 MeV Neutron Source

    CERN Document Server

    Pillon, Mario; Pizzuto, Aldo; Pietropaolo, Antonino

    2014-01-01

    The international community agrees on the importance to build a large facility devoted to test and validate materials to be used in harsh neutron environments. Such a facility, proposed by ENEA , reconsiders a previous study known as “Sorgentina” but takes into account new technological development so far attained. The “New Sorgentina” Fusion Source (NSFS) project is based upon an intense D - T 14 MeV neutron source achievable with T and D ion beams impinging on 2 m radius rotating target s . NSFS produces about 1 x10 13 n cm - 2 s - 1 over about 50 cm 3 . The NSFS facility will use the ion source and accelerating system technology developed for the Positive Ion Injectors (PII) used to heat the plasma in the fusion experiments,. NSFS, to be intended as an European facility, may be realized in a few years, once provided a preliminary technological program devote to study the operation of the ion source in continuous mode, target h eat loading/ removal, target and tritium handling, inventory as well as ...

  16. Design and Experimental Study of the External H~- Ion Source for a 10 MeV Medical Cyclotron

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    A 10 MeV medical cyclotron has been designed by the BRIF Division at CIAE, for which the H- beam is axially injected to the machine. To satisfy the requirement for the cyclotron with H- ion source, a compact multicusp H- ion source has

  17. Dislocation Loops with a Burgers Vector Produced by 1 MeV Electron Irradiation in FCC Copper-Nickel

    DEFF Research Database (Denmark)

    Leffers, Torben; Barlow, P.

    1975-01-01

    Dislocation loops with Burgers vector a are formed in Cu-Ni alloys during 1 MeV electron irradiation in a high-voltage electron microscope at 350°-400°C. The dislocation loops are of interstitial type and pure edge in character with line vectors. Some of the loops are seen to dissociate into loop...

  18. Energy spectrum measurement of high power and high energy(6 and 9 MeV) pulsed x-ray source for industrial use

    Energy Technology Data Exchange (ETDEWEB)

    Takagi, Hiroyuki [Hitachi, Ltd. Power Systems Company, Ibaraki (Japan); Murata, Isao [Graduate School of Engineering, Osaka University, Osaka (Japan)

    2016-06-15

    Industrial X-ray CT system is normally applied to non-destructive testing (NDT) for industrial product made from metal. Furthermore there are some special CT systems, which have an ability to inspect nuclear fuel assemblies or rocket motors, using high power and high energy (more than 6 MeV) pulsed X-ray source. In these case, pulsed X-ray are produced by the electron linear accelerator, and a huge number of photons with a wide energy spectrum are produced within a very short period. Consequently, it is difficult to measure the X-ray energy spectrum for such accelerator-based X-ray sources using simple spectrometry. Due to this difficulty, unexpected images and artifacts which lead to incorrect density information and dimensions of specimens cannot be avoided in CT images. For getting highly precise CT images, it is important to know the precise energy spectrum of emitted X-rays. In order to realize it we investigated a new approach utilizing the Bayesian estimation method combined with an attenuation curve measurement using step shaped attenuation material. This method was validated by precise measurement of energy spectrum from a 1 MeV electron accelerator. In this study, to extend the applicable X-ray energy range we tried to measure energy spectra of X-ray sources from 6 and 9 MeV linear accelerators by using the recently developed method. In this study, an attenuation curves are measured by using a step-shaped attenuation materials of aluminum and steel individually, and the each X-ray spectrum is reconstructed from the measured attenuation curve by the spectrum type Bayesian estimation method. The obtained result shows good agreement with simulated spectra, and the presently developed technique is adaptable for high energy X-ray source more than 6 MeV.

  19. Bunch evolution study in optimization of MeV ultrafast electron diffraction

    Science.gov (United States)

    Lu, Xian-Hai; Du, Ying-Chao; Huang, Wen-Hui; Tang, Chuan-Xiang

    2014-12-01

    Megaelectronvolt ultrafast electron diffraction (UED) is a promising detection tool for ultrafast processes. The quality of diffraction image is determined by the transverse evolution of the probe bunch. In this paper, we study the contributing terms of the emittance and space charge effects to the bunch evolution in the MeV UED scheme, employing a mean-field model with an ellipsoidal distribution as well as particle tracking simulation. The small transverse dimension of the drive laser is found to be critical to improve the reciprocal resolution, exploiting both smaller emittance and larger transverse bunch size before the solenoid. The degradation of the reciprocal spatial resolution caused by the space charge effects should be carefully controlled.

  20. Concept of a laser-plasma based electron source for sub-10 fs electron diffraction

    CERN Document Server

    Faure, J; Beaurepaire, B; Gallé, G; Vernier, A; Lifschitz, A

    2015-01-01

    We propose a new concept of an electron source for ultrafast electron diffraction with sub-10~fs temporal resolution. Electrons are generated in a laser-plasma accelerator, able to deliver femtosecond electron bunches at 5 MeV energy with kHz repetition rate. The possibility of producing this electron source is demonstrated using Particle-In-Cell simulations. We then use particle tracking simulations to show that this electron beam can be transported and manipulated in a realistic beamline, in order to reach parameters suitable for electron diffraction. The beamline consists of realistic static magnetic optics and introduces no temporal jitter. We demonstrate numerically that electron bunches with 5~fs duration and containing 1.5~fC per bunch can be produced, with a transverse coherence length exceeding 2~nm, as required for electron diffraction.

  1. Neutron yield and induced radioactivity: a study of 235-MeV proton and 3-GeV electron accelerators.

    Science.gov (United States)

    Hsu, Yung-Cheng; Lai, Bo-Lun; Sheu, Rong-Jiun

    2016-01-01

    This study evaluated the magnitude of potential neutron yield and induced radioactivity of two new accelerators in Taiwan: a 235-MeV proton cyclotron for radiation therapy and a 3-GeV electron synchrotron serving as the injector for the Taiwan Photon Source. From a nuclear interaction point of view, neutron production from targets bombarded with high-energy particles is intrinsically related to the resulting target activation. Two multi-particle interaction and transport codes, FLUKA and MCNPX, were used in this study. To ensure prediction quality, much effort was devoted to the associated benchmark calculations. Comparisons of the accelerators' results for three target materials (copper, stainless steel and tissue) are presented. Although the proton-induced neutron yields were higher than those induced by electrons, the maximal neutron production rates of both accelerators were comparable according to their respective beam outputs during typical operation. Activation products in the targets of the two accelerators were unexpectedly similar because the primary reaction channels for proton- and electron-induced activation are (p,pn) and (γ,n), respectively. The resulting residual activities and remnant dose rates as a function of time were examined and discussed.

  2. Emittance measurements for the Illinois/CEBAF polarized electron source

    Energy Technology Data Exchange (ETDEWEB)

    Dunham, B.M.; Cardman, L.S. [Illinois Univ., Urbana, IL (United States); Sinclair, C.K. [Continuous Electron Beam Accelerator Facility, Newport News, VA (United States)

    1995-01-01

    The transverse thermal properties of the electrons photoemitted from GaAs determine the intrinsic beam emittance, an important quantity in applications such as polarized electron sources and high-brightness sources. In this paper, emittance measurements using the Illinois/CEBAF polarized electron source are described. The emittance was measured as a function of both the laser beam spot size and laser wavelength at low currents. The data was used to infer the transverse thermal energy of the electrons photoemitted from GaAs for wavelengths between 514 and 840 nm. Near the bandgap the transverse energy is {approximately}34 meV, a factor of 3 lower than that of the beam from a typical thermionic electron gun. 8 refs., 2 figs.

  3. Photon activation analysis of the scraper in a 200-MeV electron accelerator using gamma-spectrometry depth profiling

    CERN Document Server

    Lijuan, He; Guobing, Yu; Guangyi, Ren; Zongjin, Duan

    2014-01-01

    For a high energy electron facility, the estimates of induced radioactivity in materials are of major importance to keep exposure to personnel and to the environment as low as reasonably achievable. In addition, an accurate prediction of induced radioactivity is also essential for the design, operation and decommissioning of a high energy electron linear accelerator. The research of induced radioactivity focuses on the photonuclear reaction, whose giant resonance response in the copper is ranging from 10 MeV to 28 MeV. The 200 MeV electron linac of NSRL is one of the earliest high-energy electron linear accelerators in P. R. China. The electrons are accelerated to 200 MeV by five acceleration tubes and collimated by the scrapers made of copper. At present, it is the first retired high-energy electron linear accelerator in domestic. Its decommissioning provides an efficient way for the induced radioactivity research of such accelerators, and is a matter of great significance to the accumulation of the induced ...

  4. MeV- and Sub-MeV-photon Sources Based on Compton Backscattering at Spring-8 and KPSI-JAEA

    Institute of Scientific and Technical Information of China (English)

    K.Kawase; M.Kando; T.Hayakawa; I.Daito; S.Kondo; T.Homma; T.Kameshima; H.Kotaki; L.Chen; Y.Fukuda; A.Faenov; Shizuma; S.V.Bulanov; T.Kimura; T.Tajima; M.Shoji; S.Suzuki; K.Tamura; H.Ohkuma; Y.Arimoto; T.Yorita; M.Fujiwara; S.Okajima

    2009-01-01

    Recently we have constructed two facilities for generating photon beams in the MeV and sub-MeV energy regions by means of the Compton backscattering with a laser and an electron beam at SPring-8 and at Kansai Photon Science Institute of Japan Atomic Energy Agency(KPSIJAEA).The MeV-photon source at SPring-8 consists of a continuous-wave optically-pumped far infrared laser with a wavelength of 118.8 μm and an 8 GeV stored electron beam.Present MeV-photon flux is estimated to be 1.3×10~3 photons/s.On the other hand,the sub-MeV-photon source at KPSI-JAEA consists of a pulse Nd:YAG laser with a wavelength of 1 064 nm and a 150 MeV electron beam accelerated by microtron.In the first trial of the photon production in this source,backscattered photon flux is estimated to be 20 photons/pulse.Both the Compton backscattered photon sources have possibilities to be used for new tools in various fields such as nuclear physics,materials science,and astronomy.

  5. Impedance Source Power Electronic Converters

    DEFF Research Database (Denmark)

    Liu, Yushan; Abu-Rub, Haitham; Ge, Baoming

    Impedance Source Power Electronic Converters brings together state of the art knowledge and cutting edge techniques in various stages of research related to the ever more popular impedance source converters/inverters. Significant research efforts are underway to develop commercially viable...... and technically feasible, efficient and reliable power converters for renewable energy, electric transportation and for various industrial applications. This book provides a detailed understanding of the concepts, designs, controls, and application demonstrations of the impedance source converters/inverters. Key...... control methods. Presents the latest power conversion solutions that aim to advance the role of power electronics into industries and sustainable energy conversion systems. Compares impedance source converter/inverter applications in renewable energy power generation and electric vehicles as well...

  6. Buncher Power Source Monitoring System of 100 MeV Cyclotron

    Institute of Scientific and Technical Information of China (English)

    WEI; Jun-yi; FU; Xiao-liang; GUO; Juan-juan; ZHANG; Yi-wang; CAO; Xue-long; YIN; Zhi-guo; JI; Bin

    2015-01-01

    The 100MeV cyclotron provides 70-100MeV and 200μA proton beam,which can be used in astrophysics,medical,defense,energy and other fields.Buncher system can enhance the beam intensity and expand the scope of application of the accelerator.Buncher system is one part of the

  7. Instrumentation developments for production and characterisation of Inverse Compton Scattering X-rays and first results with a 17 MeV electron beam

    Energy Technology Data Exchange (ETDEWEB)

    Chauchat, A.S., E-mail: anne-sophie.chauchat@cea.f [CEA, DAM, DIF, F-91297 Arpajon (France); Le Flanchec, V.; Negre, J.P.; Binet, A.; Balleyguier, P. [CEA, DAM, DIF, F-91297 Arpajon (France); Brasile, J.P. [THALES Communication, 160 Bd de Valmy, F-92700 Colombes (France); Ortega, J.M. [CLIO/LCP, Batiment 201, Universite Paris-Sud, F-91405 Orsay (France)

    2010-10-01

    An X-ray Compton source is under development at the ELSA facility. The electron beam coming from the ELSA linear accelerator interacts with a laser beam to generate an X-ray flux in the direction of the electron beam. With a 17 MeV electron beam and a 532 nm laser, the resulting X-ray maximal energy is around 11 keV. The beams visualization at the interaction point is achieved via an aluminum retractable bevel-edge with an OTR surface on one side and a slightly roughened surface on the other. Thanks to an optical beamsplitter, beam images are both transmitted to a CCD camera and to a streak camera to manage the spatial and temporal overlap of the bunches. Careful beam management and electron background noise minimization were both required to observe the first Inverse Compton Scattering X-ray profile of this source on radio-luminescent imaging plates.

  8. CESAR, 2 MeV electron storage ring; general view from above.

    CERN Multimedia

    Service Photo

    1967-01-01

    CESAR (CERN Electron Storage and Accumulation Ring) was built as a study-model for the ISR (Intersecting Storage Rings). The model had to be small (24 m circumference) and yet the particles had to be highly relativistic, which led to the choice of electrons. On the other hand, in order to model the behaviour of protons, effects from synchrotron radiation had to be negligible, which meant low magnetic fields (130 G in the bending magnets) and a corresponding low energy of 1.75 MeV. All the stacking (accumulation) procedures envisaged for the ISR were proven with CESAR, and critical aspects of transverse stability were explored. Very importantly, CESAR was the test-bed for the ultrahigh vacuum techniques and components, essential for the ISR, with a final pressure of 6E-11 Torr. The CESAR project was decided early in 1960, design was completed in 1961 and construction in 1963. After an experimental period from 1964 to 1967, CESAR was dismantled in 1968.

  9. The UHV system of the 10 MeV RF electron linac

    Science.gov (United States)

    Bhattacharjee, D.; Jayaprakash, D.; Mishra, R. L.; Nimje, V. T.; Mittal, K. C.

    2008-05-01

    A 10 MeV, 10 kW RF Electron Linac, for Industrial applications, is installed and commissioned at Electron Beam Centre (EBC), Kharghar, Navi Mumbai. The accelerator consists of the electron gun, RF Linac, Vacuum system, Beam diagnostics system, Magnetic sweep scanning system and Scan horn. The accelerator is divided into three sections with gate valves to isolate them, to enable servicing of pumps and modifications. The vacuum requirement in the accelerator is 10-7 mbar considering the breakdown parameters of the RF field within the linac. Total length of the accelerator from electron gun to the scan horn is about 5.0 meters. Vacuum plumb lines are of SS 304 pipes of nominal bores of 100 mm and 150 mm, machined internally to a surface finish of 0.8 μm. It encloses a volume of 156 litres. Total surface area exposed to vacuum is 57,500 cm2. It consists of 5250 cm2 of OFHC Copper, 51300 cm2 of SS 304 and 940 cm2 of ceramic sections. Leak-tightness of the order of 1 × 10-9mbar.l/s is ensured for the whole system, after eliminating the leaks at every stage of the assembly. Baking the plumb line and pumps at 150° C, for eight hours an ultimate vacuum of 2 × 10-7mbar is achieved in the accelerator. Modifications of the vacuum system is undertaken to suit the design changes in the gun and the diagnostic systems.

  10. The UHV system of the 10 MeV RF electron linac

    Energy Technology Data Exchange (ETDEWEB)

    Bhattacharjee, D; Jayaprakash, D; Mishra, R L; Nimje, V T; Mittal, K C [D. Bhattacharjee, Accelerator and Pulse Power Division, Bhabha Atomic Research Centre, Trombay, Mumbai, 400 085 (India)], E-mail: dhruvab@barc.gov.in

    2008-05-01

    A 10 MeV, 10 kW RF Electron Linac, for Industrial applications, is installed and commissioned at Electron Beam Centre (EBC), Kharghar, Navi Mumbai. The accelerator consists of the electron gun, RF Linac, Vacuum system, Beam diagnostics system, Magnetic sweep scanning system and Scan horn. The accelerator is divided into three sections with gate valves to isolate them, to enable servicing of pumps and modifications. The vacuum requirement in the accelerator is 10{sup -7} mbar considering the breakdown parameters of the RF field within the linac. Total length of the accelerator from electron gun to the scan horn is about 5.0 meters. Vacuum plumb lines are of SS 304 pipes of nominal bores of 100 mm and 150 mm, machined internally to a surface finish of 0.8 {mu}m. It encloses a volume of 156 litres. Total surface area exposed to vacuum is 57,500 cm{sup 2}. It consists of 5250 cm{sup 2} of OFHC Copper, 51300 cm{sup 2} of SS 304 and 940 cm{sup 2} of ceramic sections. Leak-tightness of the order of 1 x 10{sup -9}mbar.l/s is ensured for the whole system, after eliminating the leaks at every stage of the assembly. Baking the plumb line and pumps at 150 deg. C, for eight hours an ultimate vacuum of 2 x 10{sup -7}mbar is achieved in the accelerator. Modifications of the vacuum system is undertaken to suit the design changes in the gun and the diagnostic systems.

  11. Impedance source power electronic converters

    CERN Document Server

    Liu, Yushan; Ge, Baoming; Blaabjerg, Frede; Ellabban, Omar; Loh, Poh Chiang

    2016-01-01

    Impedance Source Power Electronic Converters brings together state of the art knowledge and cutting edge techniques in various stages of research related to the ever more popular impedance source converters/inverters. Significant research efforts are underway to develop commercially viable and technically feasible, efficient and reliable power converters for renewable energy, electric transportation and for various industrial applications. This book provides a detailed understanding of the concepts, designs, controls, and application demonstrations of the impedance source converters/inverters. Key features: Comprehensive analysis of the impedance source converter/inverter topologies, including typical topologies and derived topologies. Fully explains the design and control techniques of impedance source converters/inverters, including hardware design and control parameter design for corresponding control methods. Presents the latest power conversion solutions that aim to advance the role of pow...

  12. M-shell electron capture and direct ionization of gold by 25-MeV carbon and 32-MeV oxygen ions

    Energy Technology Data Exchange (ETDEWEB)

    Andrews, M.C.; McDaniel, F.D.; Duggan, J.L.; Miller, P.D.; Pepmiller, P.L.; Krause, H.; Rosseel, T.; Rayburn, L.A.; Mehta, R.; Lapicki, G.

    1984-01-01

    M-shell x-ray production cross sections have been measured for thin solid targets of Au for 25 MeV /sup 12/C/sup q+/ (q = 4, 5, 6) and for 32 MeV /sup 16/O/sup q+/ (q = 5, 7, 8). The microscopic cross sections were determined from measurements made with targets ranging in thickness from 0.5 to 100 ..mu..g/cm/sup 2/. For projectiles with one or two K-shell vacancies, the M-shell x-ray production cross sections are found to be enhanced over those by projectiles without a K-shell vacancy. The sum of direct ionization to the continuum (DI) and electron capture (EC) to the L, M, N ... shells and EC to the K-shell of the projectile have been extracted from the data. The results are compared to the predictions of first Born theories i.e. PWBA for DI and OBK of Nikolaev for EC and the ECPSSR approach that accounts for energy loss, Coulomb deflection and relativistic effects in the perturbed stationary state theory. 25 references, 3 figures, 1 table.

  13. Commissioning Status of the 3 MeV RFQ for the Compact Pulsed Hadron Source (CPHS) at Tsinghua University

    CERN Document Server

    Xing, QZ; Stovall, J; He, Y; Guan, WQ; Du, L; Cheng, C; Cai, JC; Bin, DT; Bai, YJ; Wang, XW; Wang, D; Jiang, C; Du, Q; Billen, JH; Li, J; Xiong, ZF; Xing, QZ; Zheng, SX; Zhang, HY; Yang, SY; Qiang, Q; Guan, XL; Du, TB

    2012-01-01

    The 3 MeV Radio Frequency Quadrupole (RFQ) accelerator for the Compact Pulsed Hadron Source (CPHS) is in its initial stage for the commissioning at Tsinghua University. Braze of the flanges was completed in January, 2012. The RFQ cavity has been delivered to Tsinghua University after the final field tuning. In 2012 the 3-meter-long RFQ is expected to deliver 3 MeV protons to the downstream High Energy Beam Transport (HEBT) with the peak current of 50 mA, pulse length of 0.5 ms and beam duty factor of 2.5%. The initial commissioning is now underway.

  14. Estimation of Electron Dose Delivered by a 0.4 MeV Accelerator from Bremsstrahlung Dose Measurements

    DEFF Research Database (Denmark)

    Karadjov, A. G.; Hansen, Jørgen-Walther

    1980-01-01

    Determination of a 0.4 MeV electron dose from a bremsstrahlung dose measurement using a converter-detector system is considered. The detector used is a Frickle dosimeter, and the converters are aluminum, copper and lead foils. Optimal converter thickness is ascertained experimentally for each mat...

  15. Electron beam characteristics of the 50-MeV racetrack microtron.

    Science.gov (United States)

    Karlsson, M; Nyström, H; Svensson, H

    1992-01-01

    Electron beams in the MM50 racetrack microtron are generated by computer controlled scanning of a well-focused electron pencil beam. The treatment head is optimized to give a minimum of scatter between the source position and the collimator plane by a general minimization of all scattering material in the beam and by replacement of the air in the treatment head by helium, which has a much lower linear scattering power than air. A double-focused multileaf collimator with a 31-cm collimator to patient distance is used both for electron and photon collimation. In general, no extra electron collimation is needed for the standard SSD of 100 cm. To make irregular field collimation at a distance this far from the patient possible, a number of requirements have to be fulfilled regarding the virtual source position and the spatial and angular distribution of the initial electron beam. The virtual source position has been found to be at a fixed position for different irradiation parameters. This is important for the use of the light field in electron beam treatment but also for achieving a high degree of accuracy in the dosimetry. Scatter from the multileaf collimator has not been found to give any significant contribution to the radiation field or to the monitor output factor of the MM50. Experimental dose distribution data on the MM50 have been compared to data both from other types of treatment units and to Monte Carlo simulations.

  16. Simulation of Electron Beam Dynamics in the 22 MeV Accelerator for a Coherent Electron Cooling Proof of Principle Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Owen, Justin [Stony Brook Univ., NY (United States)

    2013-12-01

    Coherent electron cooling (CeC) offers a potential new method of cooling hadron beams in colliders such as the Relativistic Heavy Ion Collider (RHIC) or the future electron ion collider eRHIC. A 22 MeV linear accelerator is currently being built as part of a proof of principle experiment for CeC at Brookhaven National Laboratory (BNL). In this thesis we present a simulation of electron beam dynamics including space charge in the 22 MeV CeC proof of principle experiment using the program ASTRA (A Space charge TRacking Algorithm).

  17. A Positron Trapping Study of Molybdenum Irradiated with 2,10, and 40 MeV Electrons

    DEFF Research Database (Denmark)

    Eldrup, Morten Mostgaard; McKee, B. T. A.; Stewart, A. T.

    1979-01-01

    Molybdenum samples of two different impurity levels (one set of a few parts per million and another set of some tens of parts per million concentration) were irradiated at about 60 degrees C with electrons of energies 2, 10, and 40 MeV. Subsequent measurements at 20 degrees C indicated...... and small vacancy clusters of average size 3-4 vacancies. Rough estimates indicate the concentration of clusters for the 10 and 40 MeV samples to be of the order of 10-50% of the monovacancy concentration....

  18. High intensity polarized electron sources

    Energy Technology Data Exchange (ETDEWEB)

    Sinclair, C.K.

    1980-10-01

    The status of the polarized electron source development program at SLAC will be reviewed. Emission currents of 60 A, corresponding to a space charge limited current density of 180 A/cm/sup 2/, have been obtained from GaAs photocathodes. Electron beam polarization 20% greater than that obtainable from GaAs cathodes has been observed from multilayer GaAs-GaAlAs structures. Work in progress to produce high beam polarization from II-IV-V/sub 2/ chalcopyrite photocathodes will also be described.

  19. Plasma Cathode Electron Sources Physics, Technology, Applications

    CERN Document Server

    Oks, Efim

    2006-01-01

    This book fills the gap for a textbook describing this kind of electron beam source in a systematic and thorough manner: from physical processes of electron emission to examples of real plasma electron sources and their applications.

  20. Measurements of photoneutrons produced by a 15 MeV electron linac for radiography applications

    Science.gov (United States)

    Huang, W. L.; Li, Q. F.; Lin, Y. Z.; Su, Q.; Luo, Y. S.

    2006-10-01

    Electrons (15 MeV) bombard a bremsstrahlung target to generate X-rays, which produces photoneutrons leading to radiation hazards and image blurring in radiography accelerators. Neutron measurements are very difficult in this type of accelerator system, due to the photon activation of high energy X-rays, the narrow pulse width of neutrons and the wide neutron spectrum. In order to study photoneutron problems, a series of experiments were conducted in our lab. At points 1 m away from the target in different directions, CR39s and BDPNDs were used to measure the neutron doses, the results of which showed that the ratios of the neutron dose to the photon dose were (0.062 ± 0.016) mSv/Gy X-ray and (0.082 ± 0.008) mSv/Gy X-ray respectively in the main X-ray beam, which agreed with Monte-Carlo simulation results within 20% and 10%. When the accelerator was equipped with shielding, activation foils were placed at a point 1 m away from the target in a 30° direction to the main beam to evaluate the activities induced by either photons or neutrons. The In foils indicated that the ratio of the fast neutron flux at this point to the photon dose at the isocenter was about (4.6 ± 0.05) × 10 4 n cm -2 Gy -1 X-ray, which agreed very well with the MCNP5 simulation.

  1. Channeling and coherent bremsstrahlung effects for relativistic positrons and electrons. [16 to 28 MeV, orientation

    Energy Technology Data Exchange (ETDEWEB)

    Walker, R. L.

    1976-03-22

    Channeling of positrons in single crystals of silicon was observed in transmission and scattering measurements for incident energies from 16 to 28 MeV. In addition, the spectral dependence upon crystal orientation of the forward coherent bremsstrahlung produced by beams of 28-MeV positrons and electrons incident upon a 5 ..mu..m thick single crystal of silicon was measured with a NaI photon spectrometer. Effects of channeling and perhaps of the nonvalidity of the first Born approximation were observed for beam directions near the (111) axis of the crystal, and coherent peaks near 0.5 MeV were observed for a compound interference direction, in agreement with first-order theoretical calculations. 32 fig.

  2. Effect of the energy of recoil atoms on conductivity compensation in moderately doped n-Si and n-SiC under irradiation with MeV electrons and protons

    Science.gov (United States)

    Kozlovski, V. V.; Lebedev, A. A.; Emtsev, V. V.; Oganesyan, G. A.

    2016-10-01

    Processes of radiation defect formation and conductivity compensation in silicon and silicon carbide irradiated with 0.9 MeV electrons are considered in comparison with the electron irradiation at higher energies. The experimental values of the carrier removal rate at the electron energy of 0.9 MeV are nearly an order of magnitude smaller than the similar values of the parameter for higher energy electrons (6-9 MeV). At the same time, the formation cross-section of primary radiation defects (Frenkel pairs, FPs) is nearly energy-independent in this range. It is assumed that these differences are due to the influence exerted by the energy of primary knocked-on atoms (PKAs). As the PKA energy increases, the average distance between the genetically related FPs grows and, as a consequence, the fraction of FPs unrecombined under irradiation becomes larger. The FP recombination radius is estimated (∼1.1 nm), which makes it possible to ascertain the charge state of the recombining components. Second, the increase in the PKA energy enables formation of new, more complex secondary radiation defects. At electron energies exceeding 15 MeV, the average PKA energies are closer to the values obtained under irradiation with 1 MeV protons, compared with an electron irradiation at the same energy. As for the radiation-induced defect formation, the irradiation of silicon with MeV protons can be, in principle, regarded as a superposition of the irradiation with 1 MeV electrons and that with silicon ions having energy of ∼1 keV, with the "source" of silicon ions generating these ions uniformly across the sample thickness.

  3. New readout and data-acquisition system in an Electron-Tracking Compton Camera for MeV Gamma-Ray Astronomy (SMILE-II)

    CERN Document Server

    Mizumoto, Tetsuya; Mizumura, Yoshitaka; Tanimori, Toru; Kubo, Hidetoshi; Takada, Atsushi; Iwaki, Satoru; Sawano, Tatsuya; Nakamura, Kiseki; Komura, Shotaro; Nakamura, Shogo; Kishimoto, Tetsuro; Oda, Makoto; Miyamoto, Shohei; Takemura, Taito; Parker, Joseph D; Tomono, Dai; Sonoda, Shinya; Miuchi, Kentaro; Kurosawa, Shunsuke

    2015-01-01

    For MeV gamma-ray astronomy, we have developed an electron-tracking Compton camera (ETCC) as a MeV gamma-ray telescope capable of rejecting the radiation background and attaining the high sensitivity of near 1 mCrab in space. Our ETCC comprises a gaseous time-projection chamber (TPC) with a micro pattern gas detector for tracking recoil electrons and a position-sensitive scintillation camera for detecting scattered gamma rays. After the success of a first balloon experiment in 2006 with a small ETCC (using a 10$\\times$10$\\times$15 cm$^3$ TPC) for measuring diffuse cosmic and atmospheric sub-MeV gamma rays (Sub-MeV gamma-ray Imaging Loaded-on-balloon Experiment I; SMILE-I), a (30 cm)$^{3}$ medium-sized ETCC was developed to measure MeV gamma-ray spectra from celestial sources, such as the Crab Nebula, with single-day balloon flights (SMILE-II). To achieve this goal, a 100-times-larger detection area compared with that of SMILE-I is required without changing the weight or power consumption of the detector syste...

  4. MeV electrons accelerated backward along laser axis from low energy, high intensity laser-water interactions

    CERN Document Server

    Feister, Scott; Morrison, John T; Frische, Kyle D; Orban, Chris; Ngirmang, Gregory; Handler, Abraham; Schillaci, Mark; Chowdhury, Enam A; Freeman, R R; Roquemore, W M

    2015-01-01

    Direct electron spectrum measurements show MeV energy electrons generated backward along the laser axis by a $\\lambda =$ 780 nm, 40 fs, 2.9 mJ short-pulse laser ($1.5 \\cdot 10^{18}$ W/cm$^2$). Electrons pass through a 3 mm hole in the center of the final off-axis paraboloid (OAP) and are characterized by a magnetic spectrometer. The charge collected at the OAP is hundreds of pC per pulse. A mechanism for this super-ponderomotive backward electron acceleration is discussed in the framework of 3D Particle-in-cell simulations.

  5. Latent track formation in germanium irradiated with 20, 30 and 40 MeV fullerenes in the electronic regime

    Energy Technology Data Exchange (ETDEWEB)

    Colder, A.; Marty, O.; Canut, B.; Levalois, M.; Marie, P. E-mail: marie@labolermat.ismra.fr; Portier, X.; Ramos, S.M.M.; Toulemonde, M

    2001-05-01

    Conventional transmission electron microscopy (TEM) and high resolution electron microscopy (HREM) have been performed on irradiated germanium with a few tens of MeV C{sub 60} incident clusters (fullerenes). Normal and inclined incidences of the beam have been investigated. As observed in the case of silicon, microscopy observations after irradiation with 20, 30 and 40 MeV beams show clearly the presence of cylindrical amorphous latent tracks of 6, 10.6 and 12.5 nm in diameter, respectively. Other microstructural considerations are reported. The difference in diameter has been interpreted in terms of high electronic energy deposited by the three different energetic fullerene beams. Furthermore, during HREM observation, a recrystallisation process of the amorphous region of the tracks has been observed and analysed.

  6. 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

  7. MeV gold irradiation induced damage in {alpha}-quartz: Competition between nuclear and electronic stopping

    Energy Technology Data Exchange (ETDEWEB)

    Toulemonde, M. E-mail: toulemonde@ganil.fr; Ramos, S.M.M.; Bernas, H.; Clerc, C.; Canut, B.; Chaumont, J.; Trautmann, C

    2001-05-01

    Damage creation in crystalline {alpha}-quartz by irradiation is studied using gold ions of energies between 0.5 and 10 MeV. For all ions, the total stopping power (dE/dx){sub tot} has a value of about 4.5 keV/nm, whereas the contribution of the electronic stopping power ranges from 0.93 keV/nm at 0.5 MeV to 3.6 keV/nm at 10 MeV. This variation allows us to test which role the nuclear and the electronic collisions plays for the damage processes. The kinetic of the ion induced damage was determined by channeling RBS and the volume increase by profilometry. Single ion impacts create damage when electronic stopping dominates, while several impacts are necessary to achieve damage in the nuclear stopping regime. A detailed analysis allows us to deduce the damage cross-sections of the two processes. The electronic stopping power of damage creation appears above an electronic dE/dx threshold of 1.4{+-}0.3 keV/nm.

  8. The ILC polarized electron source

    CERN Document Server

    Brachmann, Axel; Garwin, Edward; Kirby, Robert; Luh Dah An; Maruyama, Takashi; Prepost, Richard; Schultz, David; Sheppard, John

    2005-01-01

    The SLC polarized electron source (PES) can meet the expected requirements of the International Linear Collider (ILC) for polarization, charge and lifetime. However, experience with newer and successful PES designs at JLAB, Mainz and elsewhere can be incorporated into a first-generation ILC source that will emphasize reliability and stability without compromising the photocathode performance. The long pulse train for the ILC may introduce new challenges for the PES, and in addition more reliable and stable operation of the PES may be achievable if appropriate R&D is carried out for higher voltage operation and for a simpler load-lock system. The outline of the R&D program currently taking shape at SLAC and elsewhere is discussed. The principal components of the proposed ILC PES, including the laser system necessary for operational tests, are described.

  9. Cusp electron production in Coincidence with Target Recoil Ions for 3 MeV C^+ + Ar Collisions

    Science.gov (United States)

    Wig, A. G.; Desai, D. D.; Breinig, M.

    1996-11-01

    The production cross section and energy distribution of ionized projectile electrons are measured in coincidence with the target recoil ion charge state for 3 MeV C^+ projectiles colliding with Ar. Evidence for the importance of the electron-electron interaction is sought in the dependence of the cross section on the target recoil ion charge state and the shape of the energy distribution as a function of recoil ion charge state. While the coincidence yields suggest that the projectile electron-target electron interaction produces a significant fraction of the cusp electrons which have energy < 1 eV in the projectile frame, the measured cusp shapes are independent of recoil ion charge state. This suggest that the cusp shape is independent of the production mechanism and depends only on the interaction of the cusp electron with the remaining projectile ion.

  10. Variation of carrier concentration and interface trap density in 8MeV electron irradiated c-Si solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Bhat, Sathyanarayana, E-mail: asharao76@gmail.com; Rao, Asha, E-mail: asharao76@gmail.com [Department of Physics, Mangalore Institute of Technology and Engineering, Moodabidri, Mangalore-574225 (India); Krishnan, Sheeja [Department of Physics, Sri Devi Institute of Technology, Kenjar, Mangalore-574142 (India); Sanjeev, Ganesh [Microtron Centre, Department of Physics, Mangalore University, Mangalagangothri-574199 (India); Suresh, E. P. [Solar Panel Division, ISRO Satellite Centre, Bangalore-560017 (India)

    2014-04-24

    The capacitance and conductance measurements were carried out for c-Si solar cells, irradiated with 8 MeV electrons with doses ranging from 5kGy – 100kGy in order to investigate the anomalous degradation of the cells in the radiation harsh environments. Capacitance – Voltage measurements indicate that there is a slight reduction in the carrier concentration upon electron irradiation due to the creation of radiation induced defects. The conductance measurement results reveal that the interface state densities and the trap time constant increases with electron dose due to displacement damages in c-Si solar cells.

  11. Electron transport simulation in the range 1 keV-4 MeV for the purpose of high-resolution dosimetric application

    Energy Technology Data Exchange (ETDEWEB)

    Cobut, V. [Univ. de Cergy-Pontoise, Neuville/Oise (France). Lab. Pharmacophores Redox, Phytochimie et Radiobiologie; Cirioni, L.; Patau, J.P. [Univ. Paul Sabatier, Toulouse (France). Faculte de Pharmacie

    2001-07-01

    Experimental spectrometry and dosimetry can offer some reliable answers. However, they are not easy to implement in some specific situations. Furthermore, information on dose distributions cannot always be obtained with the desirable geometrical resolution. A way to get rid of these disadvantages consist in simulating every successive individual interactions suffered by electrons and photons along their path. We applied this principle to simulate the response of a detector placed in the field of beta-gamma sources, which maximum energy does not exceed 4 MeV. A part of this work is presented here, which concerns Monte Carlo simulation of electron transport in materials encountered in experimental dosimetric devices. Electrons were followed down to a cutoff energy of 1 keV. (orig.)

  12. Channeling and Radiation of 855 MeV Electrons and Positrons in Straight and Bent Tungsten (110) Crystals

    CERN Document Server

    Shen, H; Zhang, F S; Sushko, Gennady B; Korol, Andrei V; Solov'yov, Andrey V

    2016-01-01

    Planar channeling of 855 MeV electrons and positrons in straight and bent tungsten (110) crystal is simulated by means of the \\MBNExplorer software package. The results of simulations for a broad range of bending radii are analyzed in terms of the channel acceptance, dechanneling length, and spectral distribution of the emitted radiation. Comparison of the results with predictions of other theories as well as with the data for (110) oriented diamond, silicon and germanium crystals is carried out.

  13. Non-ambipolar Electron Source Project

    Data.gov (United States)

    National Aeronautics and Space Administration — A device to produce electron beams from magnetized plasma created with rf fields combined with electron extraction by electron sheaths is proposed. The source can...

  14. Summary of monoenergetic neutron beam sources for energies gt 14 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Brady, F.P.; Romero, J.L. (Univ. of California-Davis, Crocker Nuclear Lab., Davis, CA (US))

    1990-11-01

    This paper examines the production of neutron beams for energies between {approx}20 and 100 MeV. Considerations for obtaining monoenergetic beams as well as some of the limiting factors, such as energy resolution are examined as well. Production cross sections at 0 deg are reviewed for proton- and deuteron-induced reactions on light elements. Some current facilities in the context of neutron beams obtained by collimation, by the associate particle method, and by the use of a beam swinger are also discussed.

  15. An ultracold low emittance electron source

    CERN Document Server

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

    2014-01-01

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

  16. Neutron fluence in a 18 MeV Electron Accelerator for Therapy; Fluencia de neutrones en un Acelerador de Electrones de 18 MeV para terapia

    Energy Technology Data Exchange (ETDEWEB)

    Paredes G, L.C. [Instituto Nacional de Investigaciones Nucleares, Direccion de Innovacion Tecnologica, A.P. 18-1027, 11801 Mexico D.F. (Mexico)

    2001-07-01

    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{sup 2} were analyzed and, h) Experimental evaluation of the leakage neutron radiation from the patient and head planes, observing that the

  17. New readout and data-acquisition system in an electron-tracking Compton camera for MeV gamma-ray astronomy (SMILE-II)

    Energy Technology Data Exchange (ETDEWEB)

    Mizumoto, T., E-mail: mizumoto@cr.scphys.kyoto-u.ac.jp [Department of Physics, Kyoto University, 606-8502 Kyoto (Japan); Matsuoka, Y. [Department of Physics, Kyoto University, 606-8502 Kyoto (Japan); Mizumura, Y. [Unit of Synergetic Studies for Space, Kyoto University, 606-8502 Kyoto (Japan); Department of Physics, Kyoto University, 606-8502 Kyoto (Japan); Tanimori, T. [Department of Physics, Kyoto University, 606-8502 Kyoto (Japan); Unit of Synergetic Studies for Space, Kyoto University, 606-8502 Kyoto (Japan); Kubo, H.; Takada, A.; Iwaki, S.; Sawano, T.; Nakamura, K.; Komura, S.; Nakamura, S.; Kishimoto, T.; Oda, M.; Miyamoto, S.; Takemura, T.; Parker, J.D.; Tomono, D.; Sonoda, S. [Department of Physics, Kyoto University, 606-8502 Kyoto (Japan); Miuchi, K. [Department of Physics, Kobe University, 658-8501 Kobe (Japan); Kurosawa, S. [Institute for Materials Research, Tohoku University, 980-8577 Sendai (Japan)

    2015-11-11

    For MeV gamma-ray astronomy, we have developed an electron-tracking Compton camera (ETCC) as a MeV gamma-ray telescope capable of rejecting the radiation background and attaining the high sensitivity of near 1 mCrab in space. Our ETCC comprises a gaseous time-projection chamber (TPC) with a micro pattern gas detector for tracking recoil electrons and a position-sensitive scintillation camera for detecting scattered gamma rays. After the success of a first balloon experiment in 2006 with a small ETCC (using a 10×10×15 cm{sup 3} TPC) for measuring diffuse cosmic and atmospheric sub-MeV gamma rays (Sub-MeV gamma-ray Imaging Loaded-on-balloon Experiment I; SMILE-I), a (30 cm){sup 3} medium-sized ETCC was developed to measure MeV gamma-ray spectra from celestial sources, such as the Crab Nebula, with single-day balloon flights (SMILE-II). To achieve this goal, a 100-times-larger detection area compared with that of SMILE-I is required without changing the weight or power consumption of the detector system. In addition, the event rate is also expected to dramatically increase during observation. Here, we describe both the concept and the performance of the new data-acquisition system with this (30 cm){sup 3} ETCC to manage 100 times more data while satisfying the severe restrictions regarding the weight and power consumption imposed by a balloon-borne observation. In particular, to improve the detection efficiency of the fine tracks in the TPC from ~10% to ~100%, we introduce a new data-handling algorithm in the TPC. Therefore, for efficient management of such large amounts of data, we developed a data-acquisition system with parallel data flow.

  18. Real photon scattering up to 10 MeV: the improved facility at the Darmstadt electron accelerator S-DALINAC

    CERN Document Server

    Mohr, P J; Hartmann, T; Kaiser, H; Schiesser, D; Schmitt, S; Volz, S; Wissel, F; Zilges, A

    1999-01-01

    A new radiator and collimator system has been installed at the photon scattering facility of the superconducting electron accelerator S-DALINAC at the Darmstadt University of Technology. The new set-up allows the high-resolution (gamma,gamma') experiments to be extended to the energy range between 7 and 10 MeV without neutron induced gamma-ray background. First test measurements of sup 1 sup 1 B targets in combination with Ge(HP) detectors have been performed successfully and show the huge potential of the improved set-up.

  19. Physics design of a 10 MeV, 6 kW travelling wave electron linac for industrial applications

    Indian Academy of Sciences (India)

    NITA S KULKARNI; RINKY DHINGRA; VINIT KUMAR

    2016-11-01

    We present the physics design of a 10 MeV, 6 kW S-band (2856 MHz) electron linear accelerator (linac), which has been recently built and successfully operated at Raja Ramanna Centre for Advanced Technology, Indore. The accelerating structure is a $2\\pi/3$ mode constant impedance travelling wave structure, which comprises travelling wave buncher cells, followed by regular accelerating cells. The structure is designed to accelerate 50 keV electron beam from the electron gun to 10 MeV. This paper describes the details of electromagnetic design simulations to fix the mechanical dimensions and tolerances, as well as heat loss calculations in the structure. Results of design simulations have been compared with those obtained using approximate analytical formulae. The beam dynamics simulation with space charge is performed and the required magnetic field profile for keeping the beam focussed in the linac has been evaluated and discussed. An important feature of a travelling wave linac (in contrast with standing wave linac) is that it accepts the RF power over a band of frequencies. Threedimensional transient simulations of the accelerating structure along with the input and output couplers have beenperformed using the software CST-MWS to explicitly demonstrate this feature.

  20. Electron Accelerator Shielding Design of KIPT Neutron Source Facility

    Directory of Open Access Journals (Sweden)

    Zhaopeng Zhong

    2016-06-01

    Full Text Available 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

  1. 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

  2. Higher-order corrections to electron-nucleus bremsstrahlung cross sections above a few MeV

    Science.gov (United States)

    Mangiarotti, A.; Martins, M. N.

    2016-08-01

    Despite the fact that the first calculations of nuclear bremsstrahlung cross sections were performed for relativistic electrons more than 80 years ago by Sauter, Bethe and Heitler, and Racah, a fully satisfactory solution to this problem is still missing up to the present day. Numerical approaches are impractical for electrons with energies above a few MeV because they require a prohibitively large number of partial waves. Analytic formulae need to describe simultaneously and accurately the interaction with the Coulomb field of the nucleus and the screening effect of the atomic electrons. In the present paper, a state-of-the-art analytic calculation will be discussed. In particular, higher-order corrections to the interaction with the Coulomb field of the nucleus, a subject seldom tackled in the past, are included and compared extensively with published data. The emerged difficulties will be highlighted, but unfortunately they can be overcome only with future large coordinated theoretical and experimental efforts.

  3. Radiation sources and diagnostics with ultrashort electron bunches

    Energy Technology Data Exchange (ETDEWEB)

    Catravas, P.; Esarey, E.; Leemans, W.P.

    2001-11-02

    The basic principles and design of radiation sources (transition radiation, Cerenkov radiation, radiation from periodic structures, etc.) and radiation-based diagnostics will be discussed, with emphasis on radiation from ultra-short electron bunches. Ultra-short electron bunches have the potential to produce high peak flux radiation sources that cover wavelength regimes where sources are currently not widely available (coherent THz/IR) as well as ultrashort X-ray pulses (3-100 fs). While radiation from the electron bunch contains the full signature of the electron beam and/or medium it has travelled through, the deconvolution of a single property of interest can be difficult due to a large number of contributing properties. The experimental implementation of novel solutions to this problem will be described for beams from 30 MeV to 30 GeV, including fluctuational interferometry, source imaging, phase matched cone angles and laser-based techniques, which utilize optical transition radiation, wiggler and Cerenkov radiation, and Thomson scattering. These novel diagnostic methods have the potential to resolve fs bunch durations, slice emittance on fs scales, etc. The advantages and novel features of these techniques will be discussed.

  4. 8 MeV electron irradiation studies on electrical characteristics of Cu(In,Ga)Se{sub 2} solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Rao, Asha [Department of Physics, Mangalore Institute of Technology and Engineering, Moodabidri, Mangalore 574 227 (India); Krishnan, Sheeja; Sanjeev, Ganesh [Microtron Centre, Department of Physics, Mangalore University, Mangalagangothri 574 199 (India); Siddappa, K. [JSS Foundation for Science and Society, Bangalore 560 085 (India); Ullal, Harin S.; Wu, Xuanzhi [National Center for Photovoltaics, National Renewable Energy Laboratory, 1617, Cole Boulevard, Golden, CO 80401 (United States)

    2009-09-15

    Cu(In,Ga)Se{sub 2} (CIGS) solar cells are gaining considerable interest due to their high optical absorption coefficient and adjustable band gap, which enables them to achieve high conversion efficiency and also present many promising applications in space power systems. In this paper we report the results of the effect of temperature and 8 MeV electron irradiation on the electrical characteristics of ZnO/CdS/Cu(In,Ga)Se{sub 2}/Mo polycrystalline thin-film solar cells under forward and reverse bias studied in the temperature range 270-315 K. The solar cells were subjected to 8 MeV electron irradiation from the Microtron accelerator and were exposed to graded doses of electrons up to 75 kGy. I-V characteristics of the cells under dark and AM 1.5 illumination condition were studied before and after the irradiation. Capacitance measurements were also carried out at various frequencies before and after irradiation. In the measured temperature range, the dark current contribution is due to the generation-recombination of the minority carriers in the depletion region. The ideality factor is found to decrease with increase in temperature. It seems that electron irradiation has not altered the dark current conduction mechanism significantly. The effect of electron irradiation on the solar cell parameters such as fill factor (FF), conversion efficiency ({eta}), saturation current (I{sub o}), short circuit current (I{sub sc}), open circuit voltage (V{sub oc}), and ideality factor (n) was studied. They were found to be stable up to 75 kGy of electron dose as only small changes were observed in the solar cell parameters. (author)

  5. Dose measurements in the treatment of mycosis fungoides with total skin irradiation using a 4 MeV electron beam

    Energy Technology Data Exchange (ETDEWEB)

    Poli, M.E.R. [Hospital Real e Benemerita Sociedade Portuguesa de Beneficencia (Brazil); Todo, A.S.; Campos, L.L. [Instituto de Pesquisas Energeticas e Nucleares, CNEN/SP Travessa R, Sao Paulo (Brazil)

    2000-05-01

    The total skin irradiation (TSI) is one of the most efficient techniques in the treatment administered with curative intent of the mycosis fungoides. The cure may be obtained in 10% to 40% of cases. The original Stanford University technique, created in 1960, was applied in a 4.8 MeV linear accelerator, that provided 2.5 MeV electrons in the patient, by the use of 4 couple beams with the patient placed in front of the beam, 3 meters distant from the apparatus. In this work we describe a 4 MeV electrons beam treatment method. We intend to improve the uniformity of the dose in the patient, as well, to reduce the problems with the overlapping treatment fields, that occurs in conventional treatment that uses 1 meter of focus-skin distance, and the treatment time to the patient. Only one modification was done in the apparatus: the dose rate for this treatment was doubled. The patient is placed on a rotative base and he assumes successively 6 positions: stand up and perpendicular to the beam, distant 2.83 meters from the gantry, with 60 degrees of interval between the rotations. In each position, the patient receives a couple of beams (the beam angulation is 19.5 degrees above the transversal axis in the middle of the patient and 19.5 degrees below it). The dosimetric data obtained were compared to the international protocols (AAPM). The delivered doses in the patient were measured with thermoluminescent dosimeters placed on skin surface and with Kodak XV-2 films placed between different slabs of an anthropomorphic phantom. The dose distribution in the phantom shows a good uniformity, in all thickness of interest, so it is possible to use this technique in the treatment of the mycosis fungoides as well Kaposi's sarcoma. (author)

  6. Simulation of a Compact Neutron Source with 13MeV Cyclotron

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jeong ho; Lee, Seung Wook [Pusan National University, Busan (Korea, Republic of); Moon, Myung Kook; Hur, Min Goo; Kim, GTae Joo [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-10-15

    In this presentation, we calculated neutron flux and neutron energy spectrum in 13MeV Cyclotron. Additionally, we found suitable design of target, metal layer and cooling system. We could find an opportunity about neutron radiography system by using cyclotron. For neutron radiography, fast neutron have to shift thermal range. We need to study this direction. Monte Carlo code is not almighty, so we need to refer to this data. This presentation can be first step to prove to operate KIRAMS-13 in Pusan National University. Proton accelerator is valuable for neutron generator for neutron generator. This paper is aim to verify possibility to get neutron from KIRAMS-13, which is located in Pusan national university and optimize neutron target. To get nice quality of neutrons, it is necessary to study neutron flux and neutron energy spectrum. In order to get neutronic data, the simulation is conducted by using Monte Carlo method with Geant4 code. Regarding target design, which is consist of Beryllium target, metal layer and cooling system, simulation is conducted below many different combinations.

  7. Polarized electrons at Bates: Source to storage ring

    Science.gov (United States)

    Zwart, Townsend; Booth, E.; Casagrande, F.; Dow, K.; Farkhondeh, M.; Franklin, W.; Ihloff, E.; Jacobs, K.; Matthews, J.; Milner, R.; Smith, T.; Tschalaer, C.; Tsentalovich, E.; Turchinetz, W.; Wang, F.

    2001-09-01

    The MIT Bates 1 GeV electron scattering facility has recently completed a demanding set of parity violating experiments on the proton and the deuteron. These experiments required a polarized electron beam of unprecedented quality and high average currents. The facility has invested heavily in infrastructure for producing polarized beams and measuring beam polarization. This infrastructure includes a test beam set-up, a transmission polarimeter at 20 MeV, a laser back-scattering Compton polarimeter and a Siberian Snake. The polarized source group is also actively pursuing laser systems and photocathodes that could deliver high polarization, high peak current and moderate average current beams to meet the needs of the physics programs at Bates in the coming years.

  8. Evaluation of various operational and dosimetric parameters of an industrial electron beam accelerator of 2 MeV energy

    Science.gov (United States)

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

    2014-07-01

    An industrial type 2 MeV/20 kW ILU-6 electron beam accelerator is operational in India for development of applications and technology demonstration to the Indian Industry in the field of polymer modifications (cross-linking and degradation). In order to adjust the treatment conditions and to control the good operation of the accelerator, it is necessary to study dose response as a function of various operational parameters. An experimental procedure for calibrating Cellulose Triacetate (CTA) film strip dosimeters in electron beam using total absorption graphite calorimeters is discussed and compared it with the results obtained from gamma calibration. Dosimetry data for process application, where the irradiation target is plane polymer sheet, have been obtained under various operational parameters.

  9. Power Sources for Ultra Low Power Electronics

    Science.gov (United States)

    2000-06-12

    DARPA asked JASON to examine the issue of power sources for low power electronics with a specific emphasis on the properties of nuclear batteries and...integrated power sources combining power and electronics. During the 1998 Summer Study a workshop was held to provide background for the study, with

  10. Accuracy evaluation of a Compton X-ray spectrometer with bremsstrahlung X-rays generated by a 6 MeV electron bunch

    Energy Technology Data Exchange (ETDEWEB)

    Kojima, Sadaoki, E-mail: kojima-s@ile.osaka-u.ac.jp; Arikawa, Yasunobu; Zhang, Zhe; Ikenouchi, Takahito; Morace, Alessio; Nagai, Takahiro; Abe, Yuki; Sakata, Shouhei; Inoue, Hiroaki; Utsugi, Masaru; Nakai, Mitsuo; Nishimura, Hiroaki; Shiraga, Hiroyuki; Fujioka, Shinsuke; Azechi, Hiroshi [Institute of Laser Engineering, Osaka University, 2-6 Yamada-oka, Suita, Osaka 565-0871 (Japan); Nishimura, Yasuhiko; Togawa, Hiromi [Toyota Technical Development Corporation, 1-21 Imae, Hanamoto-cho, Toyota, Aichi 470-0334 (Japan); Ozaki, Tetsuo [National Institute for Fusion Science, 322-6 Oroshicho, Toki, Gifu 509-5292 (Japan); Kato, Ryukou [The Institute of Science and Industrial Research, Osaka University, 2-6 Yamada-oka, Suita, Osaka (Japan)

    2014-11-15

    A Compton-scattering-based X-ray spectrometer is developed to obtain the energy distribution of fast electrons produced by intense laser and matter interactions. Bremsstrahlung X-rays generated by fast electrons in a material are used to measure fast electrons’ energy distribution in matter. In the Compton X-ray spectrometer, X-rays are converted into recoil electrons by Compton scattering in a converter made from fused silica glass, and a magnet-based electron energy analyzer is used to measure the energy distribution of the electrons that recoil in the direction of the incident X-rays. The spectrum of the incident X-rays is reconstructed from the energy distribution of the recoil electrons. The accuracy of this spectrometer is evaluated using a quasi-monoenergetic 6 MeV electron bunch that emanates from a linear accelerator. An electron bunch is injected into a 1.5 mm thick tungsten plate to produce bremsstrahlung X-rays. The spectrum of these bremsstrahlung X-rays is obtained in the range from 1 to 9 MeV. The energy of the electrons in the bunch is estimated using a Monte Carlo simulation of particle-matter interactions. The result shows that the spectrometer's energy accuracy is ±0.5 MeV for 6.0 MeV electrons.

  11. LPI: electron source for LIL

    CERN Document Server

    Photographic Service

    1991-01-01

    This is where the beam for LEP began. The round metal box at the far right contains the electron-emitting cathode. After extraction, the low-energy electrons are focused with solenoids (blue) and formed into bunches. The "buncher", partly buried in the first solenoid, is fed by the descending brown transmission line. From there on, it was a long way through LIL-V, LIL-W, EPA, PS, SPS, and finally LEP.

  12. INTEGRAL and XMM-Newton observations towards the unidentified MeV source GRO J1411-64

    CERN Document Server

    Torres, D F; Reimer, O; Barcons, X; Corral, A; Bosch-Ramon, V; Paredes, J M; Romero, G E; Qu, J L; Collmar, W; Schönfelder, V; Butt, Y; Torres, Diego F.; Zhang, Shu; Reimer, Olaf; Barcons, Xavier; Corral, Amalia; Bosch-Ramon, Valenti; Paredes, Josep M.; Romero, Gustavo E.; Qu, Jin Lu; Collmar, Werner; Butt, Yousaf

    2006-01-01

    The COMPTEL unidentified source GRO J1411-64 was observed by INTEGRAL, and its central part, also by XMM-Newton. The data analysis shows no hint for new detections at hard X-rays. The upper limits in flux herein presented constrain the energy spectrum of whatever was producing GRO J1411-64, imposing, in the framework of earlier COMPTEL observations, the existence of a peak in power output located somewhere between 300-700 keV for the so-called low state. The Circinus Galaxy is the only source detected within the 4$\\sigma$ location error of GRO J1411-64, but can be safely excluded as the possible counterpart: the extrapolation of the energy spectrum is well below the one for GRO J1411-64 at MeV energies. 22 significant sources (likelihood $> 10$) were extracted and analyzed from XMM-Newton data. Only one of these sources, XMMU J141255.6-635932, is spectrally compatible with GRO J1411-64 although the fact the soft X-ray observations do not cover the full extent of the COMPTEL source position uncertainty make an...

  13. Spectroscopic and thermal studies of 8 MeV electron beam irradiated HPMC films

    Energy Technology Data Exchange (ETDEWEB)

    Sangappa [Department of Studies in Physics, Mangalore University, Mangalagangotri 574 199 (India)], E-mail: syhalabhavi@yahoo.co.in; Asha, S. [Department of Studies in Physics, Mangalore University, Mangalagangotri 574 199 (India); Demappa, T. [Department of Studies in Polymer Science, University of Mysore, Sir M.V.P.G. Center, Mandya 571 402 (India); Sanjeev, Ganesh [Microtron Centre, Mangalore University, Mangalagangotri 574 199 (India); Parameswara, P.; Somashekar, R. [Department of Studies in Physics, University of Mysore, Manasagangotri, Mysore 570 006 (India)

    2009-07-01

    Radiation-induced changes in hydroxypropyl methylcellulose (HPMC) films under electron irradiation were investigated and correlated with dose. Polymer samples were irradiated in air at room temperature by an electron beam accelerator in the range of 0-100 kGy. Various properties of the irradiated films were studied using a Ultraviolet-Visible spectrophotometer and Fourier transform infrared spectroscopy and thermogravimetric analysis. Electron irradiation was found to induce changes in the physical, chemical and thermal properties, depending on the irradiation dose.

  14. The influence of structure depth on image blurring of micrometres-thick specimens in MeV transmission electron imaging.

    Science.gov (United States)

    Wang, Fang; Sun, Ying; Cao, Meng; Nishi, Ryuji

    2016-04-01

    This study investigates the influence of structure depth on image blurring of micrometres-thick films by experiment and simulation with a conventional transmission electron microscope (TEM). First, ultra-high-voltage electron microscope (ultra-HVEM) images of nanometer gold particles embedded in thick epoxy-resin films were acquired in the experiment and compared with simulated images. Then, variations of image blurring of gold particles at different depths were evaluated by calculating the particle diameter. The results showed that with a decrease in depth, image blurring increased. This depth-related property was more apparent for thicker specimens. Fortunately, larger particle depth involves less image blurring, even for a 10-μm-thick epoxy-resin film. The quality dependence on depth of a 3D reconstruction of particle structures in thick specimens was revealed by electron tomography. The evolution of image blurring with structure depth is determined mainly by multiple elastic scattering effects. Thick specimens of heavier materials produced more blurring due to a larger lateral spread of electrons after scattering from the structure. Nevertheless, increasing electron energy to 2MeV can reduce blurring and produce an acceptable image quality for thick specimens in the TEM.

  15. On the possibility of generating low-energy positrons on accelerators of electrons with a beam energy of a few MeV and on terawatt lasers

    Science.gov (United States)

    Gorlova, D. A.; Nedorezov, V. G.; Ivanov, K. A.; Savel'ev, A. B.; Turinge, A. A.; Tsymbalov, I. N.

    2017-06-01

    Based on the numerical simulations, we estimate the possibility of generating positrons by low-energy electrons (below 10 MeV) produced by electron accelerators and femtosecond lasers. A review of experimental work reported in the literature is presented. The simulation is carried out using the GEANT-4 software package for the particular conditions of a possible experiment at the terawatt femtosecond laser facility of the International Laser Centre at the Moscow State University and the LUE-8 MeV linear electron accelerator at the Institute for Nuclear Research, Russian Academy of Sciences.

  16. A Compact Light Source: Design and Technical Feasibility Study of a Laser-Electron Storage Ring X-Ray Source

    Energy Technology Data Exchange (ETDEWEB)

    Loewen, R

    2004-02-02

    Thomson scattering infrared photons off energetic electrons provides a mechanism to produce hard X-rays desirable for applied sciences research. Using a small, modest energy (25MeV) electron storage ring together with a resonantly-driven optical storage cavity, a narrow spectrum of hard X-rays could be produced with the quality and monochromatic intensity approaching that of beamline sources at large synchrotron radiation laboratories. The general design of this X-ray source as well as its technical feasibility are presented. In particular, the requirements of optical pulse gain enhancement in an external cavity are described and experimentally demonstrated using a CW mode-locked laser.

  17. Accuracy of the phase space evolution dose calculation model for clinical 25 MeV electron beams

    Energy Technology Data Exchange (ETDEWEB)

    Korevaar, Erik W. [Daniel den Hoed Cancer Center, University Hospital Rotterdam, PO Box 5201, 3008 AE Rotterdam (Netherlands). E-mail: korevaar at kfih.azr.nl; Akhiat, Abdelhafid; Heijmen, Ben J.M. [Daniel den Hoed Cancer Center, University Hospital Rotterdam, PO Box 5201, 3008 AE Rotterdam (Netherlands); Huizenga, Henk [Joint Center for Radiation Oncology Arnhem-Nijmegen, University Medical Center Nijmegen, PO Box 9101, 6500 HB Nijmegen (Netherlands)

    2000-10-01

    The phase space evolution (PSE) model is a dose calculation model for electron beams in radiation oncology developed with the aim of a higher accuracy than the commonly used pencil beam (PB) models and with shorter calculation times than needed for Monte Carlo (MC) calculations. In this paper the accuracy of the PSE model has been investigated for 25 MeV electron beams of a MM50 racetrack microtron (Scanditronix Medical AB, Sweden) and compared with the results of a PB model. Measurements have been performed for tests like non-standard SSD, irregularly shaped fields, oblique incidence and in phantoms with heterogeneities of air, bone and lung. MC calculations have been performed as well, to reveal possible errors in the measurements and/or possible inaccuracies in the interaction data used for the bone and lung substitute materials. Results show a good agreement between PSE calculated dose distributions and measurements. For all points the differences - in absolute dose - were generally well within 3% and 3 mm. However, the PSE model was found to be less accurate in large regions of low-density material and errors of up to 6% were found for the lung phantom. Results of the PB model show larger deviations, with differences of up to 6% and 6 mm and of up to 10% for the lung phantom; at shortened SSDs the dose was overestimated by up to 6%. The agreement between MC calculations and measurement was good. For the bone and the lung phantom maximum deviations of 4% and 3% were found, caused by uncertainties about the actual interaction data. In conclusion, using the phase space evolution model, absolute 3D dose distributions of 25 MeV electron beams can be calculated with sufficient accuracy in most cases. The accuracy is significantly better than for a pencil beam model. In regions of lung tissue, a Monte Carlo model yields more accurate results than the current implementation of the PSE model. (author)

  18. Accuracy of the phase space evolution dose calculation model for clinical 25 MeV electron beams

    Science.gov (United States)

    Korevaar, Erik W.; Akhiat, Abdelhafid; Heijmen, Ben J. M.; Huizenga, Henk

    2000-10-01

    The phase space evolution (PSE) model is a dose calculation model for electron beams in radiation oncology developed with the aim of a higher accuracy than the commonly used pencil beam (PB) models and with shorter calculation times than needed for Monte Carlo (MC) calculations. In this paper the accuracy of the PSE model has been investigated for 25 MeV electron beams of a MM50 racetrack microtron (Scanditronix Medical AB, Sweden) and compared with the results of a PB model. Measurements have been performed for tests like non-standard SSD, irregularly shaped fields, oblique incidence and in phantoms with heterogeneities of air, bone and lung. MC calculations have been performed as well, to reveal possible errors in the measurements and/or possible inaccuracies in the interaction data used for the bone and lung substitute materials. Results show a good agreement between PSE calculated dose distributions and measurements. For all points the differences - in absolute dose - were generally well within 3% and 3 mm. However, the PSE model was found to be less accurate in large regions of low-density material and errors of up to 6% were found for the lung phantom. Results of the PB model show larger deviations, with differences of up to 6% and 6 mm and of up to 10% for the lung phantom; at shortened SSDs the dose was overestimated by up to 6%. The agreement between MC calculations and measurement was good. For the bone and the lung phantom maximum deviations of 4% and 3% were found, caused by uncertainties about the actual interaction data. In conclusion, using the phase space evolution model, absolute 3D dose distributions of 25 MeV electron beams can be calculated with sufficient accuracy in most cases. The accuracy is significantly better than for a pencil beam model. In regions of lung tissue, a Monte Carlo model yields more accurate results than the current implementation of the PSE model.

  19. Convertible source system of thermal neutron and X-ray at Hokkaido University electron linac facility

    Science.gov (United States)

    Kamiyama, T.; Hara, K. Y.; Taira, H.; Sato, H.

    2016-11-01

    The convertible source system for the neutron and the X-ray imagings was installed in the 45MeV electron linear accelerator facility at Hokkaido University. The source system is very useful for a complementary imaging. The imaging measurements for a sample were performed with both beams by using a vacuum tube type image intensifier. The enhanced contrast was obtained from the dataset of the radiograms measured with the neutron and X-ray beams.

  20. Local electron spectrum above 100 MeV derived from gamma-ray emissivity spectra

    Science.gov (United States)

    Strong, A. W.

    1985-01-01

    Two new determinations of the local gamma-ray emmissivity spectrum are in good accord and were used to derive constraints on the local electron spectrum. The requirement for an electron intensity above 1 GeV larger than previously believed is confirmed and no low energy upturn is then needed.

  1. Design of a 2 MeV Compton scattering gamma-ray source for DNDO missions

    Energy Technology Data Exchange (ETDEWEB)

    Hartemann, F V; Albert, F

    2009-08-24

    Nuclear resonance fluorescence-based isotope-specific detection and imaging is a powerful new technology that can enable access to new mission spaces for DNDO. Within this context, the development of advanced mono-energetic gamma ray sources plays an important role in the DNDO R&D portfolio, as it offers a faster, more precise, and safer alternative to conventional Bremsstrahlung sources. In this report, a specific design strategy is presented, along with a series of theoretical and computational tools, with the goal of optimizing source parameters for DNDO applications. In parallel, key technologies are outlined, along with discussions justifying specific choices and contrasting those with other alternatives. Finally, a complete conceptual design is described, and machine parameters are presented in detail.

  2. Giant electromagnetic vortex and MeV monoenergetic electrons generated by short laser pulses in underdense plasma near quarter critical density region.

    Science.gov (United States)

    Zhidkov, Alexei; Nemoto, Koshichi; Nayuki, Takuya; Oishi, Yuji; Fuji, Takashi

    2007-07-01

    Very efficient generation of monoenergetic, about 1MeV , electrons from underdense plasma with its electron density close to the critical, when irradiated by an intense femtosecond laser pulse, is found via two dimensional particle-in-cell simulation. The stimulated Raman scattering of a laser pulse with frequency omega300 keV .

  3. Electron and photon beams from a 50 MeV racetrack microtron.

    Science.gov (United States)

    Brahme, A; Kraepelien, T; Svensson, H

    1980-01-01

    The quality of broad high energy photon and electron beams can be improved considerably by the scanning of elementary narrow beams. Dose distributions produced in this way have advantages with respect to improved dose gradients and therapeutic ranges for electrons and lower surface doses, increased depth doses and half value depths for photons. The possibility of giving the whole therapeutic dose in a single local pulse of short duration is discussed as a new method to protect superficial tissues.

  4. Possible Explanation of the Electron Positron Anomaly at 17 MeV in $^8Be$ Transitions Through a Light Pseudoscalar

    CERN Document Server

    Ellwanger, Ulrich

    2016-01-01

    We estimate the values of Yukawa couplings of a light pseudoscalar A with a mass of about 17 MeV, which would explain the $^8Be$ anomaly observed in the Atomki pair spectrometer experiment. The resulting couplings of A to up and down type quarks are about 0.3 times the coupling of the standard Higgs boson. Then constraints from K and B decays require that loop contributions to flavour changing vertices cancel at least at the 10% level. Constraints from beam dump experiments require the coupling of A to electrons to be larger than about 4 times the coupling of the standard Higgs boson, leading to a short enough A life time consistent with an explanation of the anomaly.

  5. Electronic Stopping Power for 0.05-10 MeV Protons in a Group of Organic Materials

    Institute of Scientific and Technical Information of China (English)

    TAN Zhen-Yu; XIA Yue-Yuan; ZHAO Ming-Wen; LIU Xiang-Dong; ZHANG Li-Ming

    2008-01-01

    Electronic stopping powers for 0.05-10 Me V protons in a group of organic materials are systematically calculated. The calculations are based on Ashley's dielectric model, and an evaluation approach of optical energy loss function is incorporated into Ashley's model because no experimental optical data are available for most of the organic materials under consideration. The Barkas-effect correction and Bloch correction are included. The proton stopping powers for the considered organic materials except for mylar in the energy range from 0.05 to 10 MeV are presented for the first time. The results may be useful for studies of various radiation effects in these materials and for space research.

  6. An Efficient Microwave Power Source: Free-electron Laser Afterburner

    Energy Technology Data Exchange (ETDEWEB)

    Wang, C.; Sessler, Andrew M.

    1993-03-04

    A kind of microwave power source, called a free-electron laser afterburner (FEL afterburner) which consists of a free-electron laser buncher and a slow-wave output structure sharing a magnetic wiggler field with the buncher, is proposed. The buncher and the slow-wave structure can operate in either a travelling-wave state or a standing-wave state. In the buncher, the wiggler field together with the radiation field makes an electron beam bunched, and in the slow-wave structure the wiggler field keeps the beam bunched while the bunched beam interacts strongly with the slow-wave structure and so produces rf power. The bunching process comes from the free-electron laser mechanism and the generating process of rf power is in a slow-wave structure. A three-dimensional, time-dependent code is used to simulate a particular standing-wave FEL afterburner and it is shown that rf power of up to 1.57 GW can be obtained, at 17.12 GHz, from a l-kA, 5-MeV electron beam.

  7. PLC Control System Based on EPICS for 10 MeV Electron Linac

    Institute of Scientific and Technical Information of China (English)

    LIU; Bao-jie; ZHANG; Li-feng; ZHU; Zhi-bin

    2013-01-01

    Control system of the electron Linac using Distributed Control System(DCS)was studied here.The hardware of control system consists of siemens programmable logical controllers(PLCs)and industrial computers,and the software is developed based on experimental physics and industrial control system

  8. Radiation-induced damage and recovery effects in GG17 glass irradiated by 1 MeV electrons

    Energy Technology Data Exchange (ETDEWEB)

    Wang Qingyan, E-mail: wqyhit03s@126.com [Department of Physics, Harbin Institute of Technology, Harbin 150006 (China); Zhang Zhonghua [Institute of Opto-Electronics, Harbin Institute of Technology, Harbin (China); Geng Hongbin; Sun Chengyue; Yang Dezhuang; He Shiyu [Space Materials and Environment Engineering Laboratory, Harbin Institute of Technology, Harbin (China); Hu Zhaochu [State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences, Wuhan 430074 (China)

    2012-06-15

    The optical properties and microstructural damage of GG17 glasses, as well as their recovery during annealing at room temperature, are investigated after exposure to 1 MeV electrons with various fluences. Experimental results show that the electrons lead to severe optical degradation in the GG17 glass, and induce the formation of paramagnetic defects which can be mainly attributed to the boron-oxygen hole centers. With increasing annealing time at room temperature their decay serves as long-lived defects following first order kinetics. Except for the strong absorption bands located at 334-352 nm and 480 nm that corresponds to the boron-oxygen hole centers, weaker absorption bands appear at 780 nm or 794.6 nm after irradiation, inducing a decrease in transmittance by approximately 17% for a fluence of 1 Multiplication-Sign 10{sup 16} cm{sup -2}. It is shown that electron irradiation could cause a harmful effect on rubidium lamps when GG17 glass is used as the lamp envelope material.

  9. MeV femtosecond electron pulses from direct-field acceleration in low density atomic gases

    CERN Document Server

    Varin, Charles; Hogan-Lamarre, Pascal; Fennel, Thomas; Piché, Michel; Brabec, Thomas

    2015-01-01

    Using three-dimensional particle-in-cell simulations, we show that few-MeV electrons can be produced by focusing tightly few-cycle radially-polarized laser pulses in a low-density atomic gas. In particular, it is observed that for the few-TW laser power needed to reach relativistic electron energies, longitudinal attosecond microbunching occurs naturally, resulting in femtosecond structures with high-contrast attosecond density modulations. The three-dimensional particle-in-cell simulations show that in the relativistic regime the leading pulse of these attosecond substructures survives to propagation over extended distances, suggesting that it could be delivered to a distant target, with the help of a properly designed transport beamline.

  10. Electron beam ion source and electron beam ion trap (invited).

    Science.gov (United States)

    Becker, Reinard; Kester, Oliver

    2010-02-01

    The electron beam ion source (EBIS) and its trap variant [electron beam ion trap (EBIT)] celebrated their 40th and 20th anniversary, respectively, at the EBIS/T Symposium 2007 in Heidelberg. These technologically challenging sources of highly charged ions have seen a broad development in many countries over the last decades. In contrast to most other ion sources the recipe of improvement was not "sorcery" but a clear understanding of the physical laws and obeying the technological constraints. This review will report important achievements of the past as well as promising developments in the future.

  11. Electron beam ion source and electron beam ion trap (invited)

    Energy Technology Data Exchange (ETDEWEB)

    Becker, Reinard [Scientific Software Service, Kapellenweg 2a, D-63571 Gelnhausen (Germany); Kester, Oliver [National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824 (United States)

    2010-02-15

    The electron beam ion source (EBIS) and its trap variant [electron beam ion trap (EBIT)] celebrated their 40th and 20th anniversary, respectively, at the EBIS/T Symposium 2007 in Heidelberg. These technologically challenging sources of highly charged ions have seen a broad development in many countries over the last decades. In contrast to most other ion sources the recipe of improvement was not ''sorcery'' but a clear understanding of the physical laws and obeying the technological constraints. This review will report important achievements of the past as well as promising developments in the future.

  12. Fast neutron leakage in 18 MeV medical electron accelerator

    CERN Document Server

    Paredes, L; Balcazar, M; Tavera, L; Camacho, E

    1999-01-01

    In this work the neutron fluence of the Varian Clinac 2100C Medical Accelerator has been evaluated using CR39 track dosimeter. The assessment of fast neutron dose to a patient for typical treatment of 200 cGy with an 18 MV photons beam is performed at surface-source distance of 100 cm with a field size of 20x20 cm sup 2. Fast neutron leakage around of the accelerator head is evaluated.

  13. Thermoluminescence spectra of natural CaF{sub 2} irradiated by 10MeV electrons

    Energy Technology Data Exchange (ETDEWEB)

    Manrique, J. [Departamento de Matematicas, Fisica Aplicada y Fisicoquimica, Facultad de Ciencias Experimentales y de la Salud, Universidad San Pablo-CEU, 28668 Boadilla del Monte, Madrid (Spain)]. E-mail: jamanros@ceu.es; Angulo, S. [Departamento de Matematicas, Fisica Aplicada y Fisicoquimica, Facultad de Ciencias Experimentales y de la Salud, Universidad San Pablo-CEU, 28668 Boadilla del Monte, Madrid (Spain); Pardo, M.P. [Departamento de Ciencias Quimicas, Facultad de Ciencias Experimentales y de la Salud, Universidad San Pablo-CEU, 28668 Boadilla del Monte, Madrid (Spain); Gastesi, R. [Departamento de Matematicas, Fisica Aplicada y Fisicoquimica, Facultad de Ciencias Experimentales y de la Salud, Universidad San Pablo-CEU, 28668 Boadilla del Monte, Madrid (Spain); De la Cruz, A. [Departamento de Matematicas, Fisica Aplicada y Fisicoquimica, Facultad de Ciencias Experimentales y de la Salud, Universidad San Pablo-CEU, 28668 Boadilla del Monte, Madrid (Spain); Perez, A. [Departamento de Matematicas, Fisica Aplicada y Fisicoquimica, Facultad de Ciencias Experimentales y de la Salud, Universidad San Pablo-CEU, 28668 Boadilla del Monte, Madrid (Spain)

    2006-02-15

    The spectra of thermoluminescence from natural and electron-irradiated fluorite in the 350-800nm spectral range were studied between room temperature and 500{sup o}C. The sample came from Asturias (Spain) and was analyzed by X-ray diffractometry and inductively coupled plasma-mass spectrometry. Glow peaks appeared at 115, 205 and 310{sup o}C. Main emissions occurred at 475, 575, 650 and 745nm, attributed to the Dy{sup +3} ion and, at 410nm, from electron-hole recombination. The fractional glow technique and the general order model were employed to study the emission at 575nm in detail. The results showed that the 115 and 205{sup o}C glow peaks originate at traps with activation energies of 1.6 and 1.9eV, respectively, on the kinetic order of 1.5 and 1.3 and frequency factors of 1.7x10{sup 19} and 2.7x10{sup 19}s{sup -1}, respectively. Spectrally resolved fading produced by storage was observed, and we concluded that the emission was due to large defect complexes. The dosimetric study showed that there was saturation at doses higher than 2kGy.

  14. Preliminary study of window silicate glass powder for EPR dosimetry with 10-MeV electron beam irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Ramezani Moghaddam, Ali, E-mail: ali-ramezani@aut.ac.ir [Department of Physics and Nuclear Engineering, AmirKabir University of Technology (Iran, Islamic Republic of); Shamsaei, Mojtaba [Department of Physics and Nuclear Engineering, AmirKabir University of Technology (Iran, Islamic Republic of); Amraei, Reza [Radiation Applications Research School, Nuclear Science and Technology Research Institute, Yazd (Iran, Islamic Republic of)

    2012-03-01

    Window silicate glass powder has been evaluated as a possible high dose dosimeter using EPR (Electron Paramagnetic Resonance) technique. In this work window glass powder with maximum dimension of 700 {mu}m was irradiated with 10 MeV electrons with doses ranging from 580 Gy to 46.52 kGy. The EPR response of the irradiated samples showed a linear behavior to applied doses up to 8 kGy. The EPR spectra of NBOHC (Non-Bonding Oxygen Hole Center) was found at g{sub 1} = 2.0092 {+-} 0.0001 and g{sub 2} = 2.0042 {+-} 0.0001. The line widths of all spectra were found to be the same. Finally, the thermal fading of EPR intensity was studied for 70 days and showed a sharp decline on the first day. This fading continued up to almost 15 days and then the slope of the decay-curve tended to gradual changes up to 50 days. Afterwards, it presented a fairly constant value with time and a predictable stability was achieved.

  15. A new international geostationary electron model: IGE-2006, from 1 keV to 5.2 MeV

    Science.gov (United States)

    Sicard-Piet, A.; Bourdarie, S.; Boscher, D.; Friedel, R. H. W.; Thomsen, M.; Goka, T.; Matsumoto, H.; Koshiishi, H.

    2008-07-01

    Département Environnement Spatial, Office National d'Etudes et de Recherches Aérospatiales (ONERA) has been developing a model for the geostationary electron environment since 2003. Until now, this model was called Particle ONERA-LANL Environment (POLE), and it is valid from 30 keV up to 5.2 MeV. POLE is based on the full complement of Los Alamos National Laboratory geostationary satellites, covers the period 1976-2005, and takes into account the solar cycle variation. Over the period 1976 to present, four different detectors were flown: charged particle analyzer (CPA), synchronous orbit particle analyzer (SOPA), energetic spectra for particles (ESP), and magnetospheric plasma analyzer (MPA). Only the first three were used to develop the POLE model. Here we extend the energy coverage of the model to low energies using MPA measurements. We further include the data from the Japanese geostationary spacecraft, Data Relay Test Satellite (DRTS). These data are now combined into an extended geostationary electron model which we call IGE-2006.

  16. AGILE detects enhanced gamma-ray emission above 100 MeV from the 3FGL J1037.2-6052 source region

    Science.gov (United States)

    Lucarelli, F.; Pittori, C.; Verrecchia, F.; Tavani, M.; Bulgarelli, A.; Munar-Adrover, P.; Minervini, G.; Piano, G.; Ursi, A.; Donnarumma, I.; Fioretti, V.; Zoli, A.; Vercellone, S.; Striani, E.; Cardillo, M.; Gianotti, F.; Trifoglio, M.; Giuliani, A.; Mereghetti, S.; Caraveo, P.; Perotti, F.; Chen, A.; Argan, A.; Costa, E.; Del Monte, E.; Evangelista, Y.; Feroci, M.; Lazzarotto, F.; Lapshov, I.; Pacciani, L.; Soffitta, P.; Sabatini, S.; Vittorini, V.; Pucella, G.; Rapisarda, M.; Di Cocco, G.; Fuschino, F.; Galli, M.; Labanti, C.; Marisaldi, M.; Pellizzoni, A.; Pilia, M.; Trois, A.; Barbiellini, G.; Vallazza, E.; Longo, F.; Morselli, A.; Picozza, P.; Prest, M.; Lipari, P.; Zanello, D.; Cattaneo, P. W.; Rappoldi, A.; Colafrancesco, S.; Parmiggiani, N.; Ferrari, A.; Paoletti, F.; Antonelli, A.; Giommi, P.; Salotti, L.; Valentini, G.; D'Amico, F.

    2017-01-01

    AGILE is detecting intense gamma-ray emission above 100 MeV from an unidentified source, AGL J1035-6055, at Galactic coordinates (l,b)=(287.19, -2.26) +/- 0.4 deg (95% stat.) +/- 0.1 deg (syst.) (R.A., Dec.= 158.96, -60.92 deg, J2000).

  17. Multibeam Electron Source using MEMS Electron Optical Components

    Energy Technology Data Exchange (ETDEWEB)

    Someren, B van; Bruggen, M J van; Zhang, Y; Hagen, C W; Kruit, P [Delft University of Technology, Lorentzweg 1, 2628 CJ Delft (Netherlands)

    2006-04-01

    Recent developments in electron beam equipment have given rise to ever more complex electron optical (EO) designs. Until now these designs were realized using standard workshop techniques like drilling, turning etc. With the need for even more complex designs to advance electron optics, we use the possibilities of manufacturing EO components with MEMS fabrication techniques. This leads to different design rules in the EO design. One can use one of the strong points of MEMS fabrication, mass manufacturing of identical and reliable components within tight specifications. One of our designs that demonstrates this is presented in this paper, the multi-beam electron source. We are developing an electron source for use in a standard scanning electron microscope that produces 100 beams instead of one. The design is made so that the performance in terms of spot size and current per beam is equal to the performance of the beam from a single beam source, around 1 nm and 25 pA. Furthermore, since we modify the SEM for nanolithography purposes, it is necessary to switch each of the individual beams on and off. For that purpose we integrate an array of blanker electrodes in the source unit.

  18. The use of a diode matrix in commissioning activities for electron energies {>=}9 MeV: A feasibility study

    Energy Technology Data Exchange (ETDEWEB)

    Casanova Borca, Valeria; Pasquino, Massimo; Ozzello, Franca; Tofani, Santi [S. C. Fisica Sanitaria, Azienda Sanitaria ASL TO 4, Via Di Vittorio 1, 10015 Ivrea, Torino (Italy)

    2009-04-15

    The contribution of a commercially available diode matrix (MapCHECK trade mark sign , provided by Sun Nuclear, Melbourne, FL) for the commissioning procedures of the voxel based Monte Carlo (VMC++) algorithm for electron beams of MasterPlan treatment planning system was investigated. The attention is mainly focused on the calculation in homogeneous and heterogeneous phantoms. With this aim, following a data set similar to that proposed by Electron Collaborative Working Group (ECWG), the dose profiles and two-dimensional (2D) dose distributions measured by the diode matrix were compared with the calculated ones using the gamma analysis method with acceptance criteria for the dose difference and the distance to agreement equal to 4% and 4 mm, respectively. The average and standard deviation of the percentage of points satisfying the constraint {gamma}{<=}1 are 98.3{+-}4.1% and 99.3{+-}1.7% for the 9 and 12 MeV electron beam, respectively, showing that the accuracy of MasterPlan electron beam algorithm is good for simple two-dimensional geometries as well as for more complicated three-dimensional ones. The results are in agreement with those reported in literature by Cygler et al. [''Evaluation of the first commercial Monte Carlo dose calculation engine for electron beam treatment planning,'' Med. Phys. 31, 142-153 (2004)]. In addition, the authors have also analyzed the response of the 2D array in terms of dose profiles at different depths, comparing the results with those obtained in water phantom using an electron diode. The results show that in the low gradient regions there were no deviations larger than the criteria of acceptability set by Van Dyk et al. [''Commissioning and quality assurance of treatment planning computers,'' Int. J. Radiat. Oncol. Biol. Phys. 26, 261-273 (1993)]; in the high gradient region, the maximum deviations are less than 2 mm with most of the values less than 1 mm. The present article shows that

  19. The use of a diode matrix in commissioning activities for electron energies > or = 9 MeV: a feasibility study.

    Science.gov (United States)

    Borca, Valeria Casanova; Pasquino, Massimo; Ozzello, Franca; Tofani, Santi

    2009-04-01

    The contribution of a commercially available diode matrix (MapCHECK, provided by Sun Nuclear, Melbourne, FL) for the commissioning procedures of the voxel based Monte Carlo (VMC++) algorithm for electron beams of MasterPlan treatment planning system was investigated. The attention is mainly focused on the calculation in homogeneous and heterogeneous phantoms. With this aim, following a data set similar to that proposed by Electron Collaborative Working Group (ECWG), the dose profiles and two-dimensional (2D) dose distributions measured by the diode matrix were compared with the calculated ones using the gamma analysis method with acceptance criteria for the dose difference and the distance to agreement equal to 4% and 4 mm, respectively. The average and standard deviation of the percentage of points satisfying the constraint gamma < or = 1 are 98.3 +/- 4.1% and 99.3 +/- 1.7% for the 9 and 12 MeV electron beam, respectively, showing that the accuracy of MasterPlan electron beam algorithm is good for simple two-dimensional geometries as well as for more complicated three-dimensional ones. The results are in agreement with those reported in literature by Cygler et al. ["Evaluation of the first commercial Monte Carlo dose calculation engine for electron beam treatment planning," Med. Phys. 31, 142-153 (2004)]. In addition, the authors have also analyzed the response of the 2D array in terms of dose profiles at different depths, comparing the results with those obtained in water phantom using an electron diode. The results show that in the low gradient regions there were no deviations larger than the criteria of acceptability set by Van Dyk et al. ["Commissioning and quality assurance of treatment planning computers," Int. J. Radiat. Oncol. Biol. Phys. 26, 261-273 (1993)]; in the high gradient region, the maximum deviations are less than 2 mm with most of the values less than 1 mm. The present article shows that MapCHECK can play a useful role in the commissioning of

  20. Electron Storage Ring Development for ICS Sources

    Energy Technology Data Exchange (ETDEWEB)

    Loewen, Roderick [Lyncean Technologies, Inc., Palo Alto, CA (United States)

    2015-09-30

    There is an increasing world-wide interest in compact light sources based on Inverse Compton Scattering. Development of these types of light sources includes leveraging the investment in accelerator technology first developed at DOE National Laboratories. Although these types of light sources cannot replace the larger user-supported synchrotron facilities, they offer attractive alternatives for many x-ray science applications. Fundamental research at the SLAC National Laboratory in the 1990’s led to the idea of using laser-electron storage rings as a mechanism to generate x-rays with many properties of the larger synchrotron light facilities. This research led to a commercial spin-off of this technology. The SBIR project goal is to understand and improve the performance of the electron storage ring system of the commercially available Compact Light Source. The knowledge gained from studying a low-energy electron storage ring may also benefit other Inverse Compton Scattering (ICS) source development. Better electron storage ring performance is one of the key technologies necessary to extend the utility and breadth of applications of the CLS or related ICS sources. This grant includes a subcontract with SLAC for technical personnel and resources for modeling, feedback development, and related accelerator physics studies.

  1. Intense X-ray sources based on compton scattering in laser electron storage rings

    CERN Document Server

    Gladkikh, P I; Karnaukhov, I M

    2002-01-01

    The main problem of the designing of intense X-ray sources based on Compton scattering in laser-electron storage ring is associated with large steady-state electron beam energy spread. In paper the principles of the development of compact storage ring lattice with large RF-acceptance and negligible chromatic effects at interaction point are considered. The storage ring with electron beam energy over the range 100-400 MeV that allows generating intense VUV from bending magnets, X-ray up to 280 keV with rate up to 10 sup 1 sup 4 photons/s and gamma-beam up to 2.8 MeV for neutron generation on beryllium target is proposed.

  2. Compact muon source with electron accelerator for a mobile muSR facility

    Energy Technology Data Exchange (ETDEWEB)

    Nagamine, K., E-mail: kanetada.nagamine@ucr.ed [Department of Physics and Astronomy, University of California, Riverside, CA 92521 (United States); Muon Science Laboratory, IMSS, KEK, Oho, Tsukuba, Ibaraki 305-0801 (Japan); Atomic Physics Laboratory, RIKEN, Wako, Saitama 351-0191 (Japan); Miyadera, H.; Jason, A. [AOT-ABS, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Seki, R. [Department of Physics, State University of California, Northridge, CA 91330-8268 (United States)

    2009-04-15

    In order to increase accessibility to the muSR spectroscopy for people in various fields of science and engineering, a conceptual design study was made to realize a compact and inexpensive muon source by using 300 MeV electron microtron and a large-acceptance muon-capture. Advanced radiography imaging with muon spin probes will become possible for bio-medical studies, inspection of re-enforced architectures, etc.

  3. Polarized Electron Source for the MOLLER Experiment

    Science.gov (United States)

    Palatchi, Caryn

    2017-01-01

    The MOLLER experiment at Jefferson Laboratory will be part of a new generation of ultra high precision electroweak experiments. It will measure the Moller (electron-electron scattering) parity-violating asymmetry, providing an unprecedented precision on the electroweak mixing angle. To achieve such small uncertainties, innovative techniques in the electron source are required to switch the beam helicity more quickly than previously achievable. The key technology is the Pockels cell in the laser optics of the polarized electron source. RTP crystals, which do not suffer from piezo-electric ringing, have been demonstrated to achieve almost an order of magnitude faster transition times than commonly used KD*P crystal cells. This talk will detail the design modifications made to the RTP cell in order to achieve beam quality which is comparable to traditional KD*P controlled accelerator beams. The specific challenges for this use of the RTP system, including laser and crystal constraints, will be discussed.

  4. Brightness measurement of an electron impact gas ion source for proton beam writing applications

    Energy Technology Data Exchange (ETDEWEB)

    Liu, N.; Santhana Raman, P. [Centre for Ion Beam Applications, Department of Physics, National University of Singapore, Singapore 117542 (Singapore); Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117583 (Singapore); Xu, X.; Pang, R.; Kan, J. A. van, E-mail: phyjavk@nus.edu.sg [Centre for Ion Beam Applications, Department of Physics, National University of Singapore, Singapore 117542 (Singapore); Khursheed, A. [Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117583 (Singapore)

    2016-02-15

    We are developing a high brightness nano-aperture electron impact gas ion source, which can create ion beams from a miniature ionization chamber with relatively small virtual source sizes, typically around 100 nm. A prototype source of this kind was designed and successively micro-fabricated using integrated circuit technology. Experiments to measure source brightness were performed inside a field emission scanning electron microscope. The total output current was measured to be between 200 and 300 pA. The highest estimated reduced brightness was found to be comparable to the injecting focused electron beam reduced brightness. This translates into an ion reduced brightness that is significantly better than that of conventional radio frequency ion sources, currently used in single-ended MeV accelerators.

  5. Sudden Intensity Increases and Radial Gradient Changes of Cosmic Ray Mev Electrons and Protons Observed at Voyager 1 Beyond 111 AU in the Heliosheath

    Science.gov (United States)

    Webber, W. R.; Mcdonald, F. B.; Cummings, A. C.; Stone, E. C.; Heikkila, B.; Lal, N.

    2012-01-01

    Voyager 1 has entered regions of different propagation conditions for energetic cosmic rays in the outer heliosheathat a distance of about 111 AU from the Sun. The low energy 614 MeV galactic electron intensity increased by 20over a time period 10 days and the electron radial intensity gradient abruptly decreased from 19AU to 8AU at2009.7 at a radial distance of 111.2 AU. At about 2011.2 at a distance of 116.6 AU a second abrupt intensity increase of25 was observed for electrons. After the second sudden electron increase the radial intensity gradient increased to18AU. This large positive gradient and the 13 day periodic variations of 200 MeV particles observed near theend of 2011 indicate that V1 is still within the overall heliospheric modulating region. The implications of these resultsregarding the proximity of the heliopause are discussed.

  6. The physics of Electron Beam Ion Sources

    Energy Technology Data Exchange (ETDEWEB)

    Stockli, M.P.; Cocke, C.L.

    1990-01-01

    There are 13 Electron Beam Ion Sources in operation which produce highly charged ions, up to Th[sup 80+] and Xe[sup 53+]. Most of the sources are used to study these ions under electron impact or when recombining with gaseous or solid targets. That provides an insight into the atomic physics of these highly charged ions and into the physics of the plasma in which such ions can be found. This paper reviews the present knowledge of atomic processes, important in the production of such ions with an EBIS.

  7. The physics of Electron Beam Ion Sources

    Energy Technology Data Exchange (ETDEWEB)

    Stockli, M.P.; Cocke, C.L.

    1990-12-31

    There are 13 Electron Beam Ion Sources in operation which produce highly charged ions, up to Th{sup 80+} and Xe{sup 53+}. Most of the sources are used to study these ions under electron impact or when recombining with gaseous or solid targets. That provides an insight into the atomic physics of these highly charged ions and into the physics of the plasma in which such ions can be found. This paper reviews the present knowledge of atomic processes, important in the production of such ions with an EBIS.

  8. The scattering of a bremsstrahlung radiation of electrons with energy 13 and 22 MeV from plane targets

    CERN Document Server

    Asatov, U T

    2002-01-01

    In the present work the characteristics of backward (90 sup d egelectrons with energy 13 and 22 MeV with plane targets of different thickness from glass textolite, aluminium, iron, lead and their combination are investigated. The dependence of thickness of saturation of 'forward' scattered gamma radiation, a on angles of detection (theta sub s) and orientation (phi) of plane targets depending on a direction of probing beam was observed for the first time. For the first time, the numerical performances of beams of forward scattered gamma radiation from different targets were investigated and determined depending on their orientation and thickness. The new and corrected data on numerical performances of beams of the inverse scattered gamma radiation is obtained. The distinction in characteristics of beams of the scattered gamma radiation is s...

  9. A magnetized Einzel lens electron dump for the Linac4 H− ion source

    CERN Document Server

    Midttun, O; Kronberger, M; Lettry, J; Pereira, H; Scrivens, R

    2013-01-01

    Linac4 is a 160 MeV linear accelerator which will inject negative hydrogen ions (H−) into CERN’s Proton Synchrotron Booster, a required upgrade to improve the beam brightness in the LHC injector chain. A volume production RF ion source, based on the design of the DESY RF source was implemented, but showed considerable electron dump ablation during operation at 45 keV beam energy. To reduce the electron beam power density in the dump, a magnetized Einzel lens is designed that reduces the beam energy to 10 keV before permanentmagnets dump the electrons on a tungsten surface. Presented in this paper are simulations of the design using IBSimu, the tunable range of parameters depending on the extracted H− and electron current, as well as details of the implementation, the choice of pulsed power converters and the electrode alignment system. In addition, simulations of proton extraction from this source will be shown.

  10. A magnetized Einzel lens electron dump for the Linac4 H- ion source

    Science.gov (United States)

    Midttun, Ø.; Kalvas, T.; Kronberger, M.; Lettry, J.; Pereira, H.; Scrivens, R.

    2013-02-01

    Linac4 is a 160 MeV linear accelerator which will inject negative hydrogen ions (H-) into CERN's Proton Synchrotron Booster, a required upgrade to improve the beam brightness in the LHC injector chain. A volume production RF ion source, based on the design of the DESY RF source was implemented, but showed considerable electron dump ablation during operation at 45 keV beam energy. To reduce the electron beam power density in the dump, a magnetized Einzel lens is designed that reduces the beam energy to 10 keV before permanentmagnets dump the electrons on a tungsten surface. Presented in this paper are simulations of the design using IBSimu, the tunable range of parameters depending on the extracted H- and electron current, as well as details of the implementation, the choice of pulsed power converters and the electrode alignment system. In addition, simulations of proton extraction from this source will be shown.

  11. Simulating the displacement effect in electronics exposed to space radiation by fission and 14 MeV neutrons; Simulation de l'effet ''deplacement d'atome'' dans l'electronique soumise au rayonnement spatial, par des neutrons de fission et des neutrons de 14 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Zyromski, Ph. [CEA Valduc, Dept. Recherche sur les Materiaux Nucleaires, 21 - Is-sur-Tille (France)

    1999-07-01

    Various spatial radiation inducing displacement effect in the on board electronics may be quantified by a 1 MeV (Si) equivalent neutron fluence. Simulating this effect is made easier by using the PROSPERO reactor (fission neutrons) or the SAMES 400 kV accelerator (14 MeV neutrons) which data are recalled. (author)

  12. Positron source position sensing detector and electronics

    Science.gov (United States)

    Burnham, Charles A.; Bradshaw, Jr., John F.; Kaufman, David E.; Chesler, David A.; Brownell, Gordon L.

    1985-01-01

    A positron source, position sensing device, particularly with medical applications, in which positron induced gamma radiation is detected using a ring of stacked, individual scintillation crystals, a plurality of photodetectors, separated from the scintillation crystals by a light guide, and high resolution position interpolation electronics. Preferably the scintillation crystals are several times more numerous than the photodetectors with each crystal being responsible for a single scintillation event from a received gamma ray. The light guide will disperse the light emitted from gamma ray absorption over several photodetectors. Processing electronics for the output of the photodetectors resolves the location of the scintillation event to a fraction of the dimension of each photodetector. Because each positron absorption results in two 180.degree. oppositely traveling gamma rays, the detection of scintillation in pairs permits location of the positron source in a manner useful for diagnostic purposes. The processing electronics simultaneously responds to the outputs of the photodetectors to locate the scintillations to the source crystal. While it is preferable that the scintillation crystal include a plurality of stacked crystal elements, the resolving power of the processing electronics is also applicable to continuous crystal scintillators.

  13. Dosimetric verification of a commercial Monte Carlo treatment planning system (VMC++) for a 9 MeV electron beam.

    Science.gov (United States)

    Schiapparelli, P; Zefiro, D; Taccini, G

    2009-05-01

    The aim of this work was to evaluate the performance of the voxel-based Monte Carlo algorithm implemented in the commercial treatment planning system ONCENTRA MASTERPLAN for a 9 MeV electron beam produced by a linear accelerator Varian Clinac 2100 C/D. In order to realize an experimental verification of the computed data, three different groups of tests were planned. The first set was performed in a water phantom to investigate standard fields, custom inserts, and extended treatment distances. The second one concerned standard field, irregular entrance surface, and oblique incidence in a homogeneous PMMA phantom. The last group involved the introduction of inhomogeneities in a PMMA phantom to simulate high and low density materials such as bone and lung. Measurements in water were performed by means of cylindrical and plane-parallel ionization chambers, whereas measurements in PMMA were carried out by the use of radiochromic films. Point dose values were compared in terms of percentage difference, whereas the gamma index tool was used to perform the comparison between computed and measured dose profiles, considering different tolerances according to the test complexity. In the case of transverse scans, the agreement was searched in the plane formed by the intersection of beam axis and the profile (2D analysis), while for percentage depth dose curves, only the beam axis was explored (1D analysis). An excellent agreement was found for point dose evaluation in water (discrepancies smaller than 2%). Also the comparison between planned and measured dose profiles in homogeneous water and PMMA phantoms showed good results (agreement within 2%-2 mm). Profile evaluation in phantoms with internal inhomogeneities showed a good agreement in the case of "lung" insert, while in tests concerning a small "bone" inhomogeneity, a discrepancy was particularly evidenced in dose values on the beam axis. This is due to the inaccurate geometrical description of the phantom that is linked

  14. Measurement of cross sections for the scattering of neutrons in the energy range from 2 MeV to 4 MeV with the {sup 15}N(p,n) reaction as neutron source; Messung von Wirkungsquerschnitten fuer die Streuung von Neutronen im Energiebereich von 2 MeV bis 4 MeV mit der {sup 15}N(p,n)-Reaktion als Neutronenquelle

    Energy Technology Data Exchange (ETDEWEB)

    Poenitz, Erik

    2010-04-26

    In future nuclear facilities, the materials lead and bismuth can play a more important role than in today's nuclear reactors. Reliable cross section data are required for the design of those facilities. In particular the neutron transport in the lead spallation target of an Accelerator-Driven Subcritical Reactor strongly depends on the inelastic neutron scattering cross sections in the energy region from 0.5 MeV to 6 MeV. In the recent 20 years, elastic and inelastic neutron scattering cross sections were measured with high precision for a variety of elements at the PTB time-of-flight spectrometer. The D(d,n) reaction was primarily used for the production of neutrons. Because of the Q value of the reaction and the available deuteron energies, neutrons in the energy range from 6 MeV to 16 MeV can be produced. For the cross section measurement at lower energies, however, another neutron producing reaction is required. The {sup 15}N(p,n){sup 15}O reaction was chosen, as it allows the production of monoenergetic neutrons with up to 5.7MeV energy. In this work, the {sup 15}N(p,n) reaction was studied with focus on the suitability as a source for monoenergetic neutrons in scattering experiments. This includes the measurement of differential cross sections for the neutron producing reaction and the choice of optimum target conditions. Differential elastic and inelastic neutron scattering cross sections were measured for lead at four energies in the region from 2 MeV to 4 MeV incident neutron energy using the time-of-flight technique. A lead sample with natural isotopic composition was used. NE213 liquid scintillation detectors with well-known detection efficiencies were used for the detection of the scattered neutrons. Angle-integrated cross sections were determined by a Legendre polynomial expansion using least-squares methods. Additionally, measurements were carried out for isotopically pure {sup 209}Bi and {sup 181}Ta samples at 4 MeV incident neutron energy

  15. Electron Source based on Superconducting RF

    Science.gov (United States)

    Xin, Tianmu

    High-bunch-charge photoemission electron-sources operating in a Continuous Wave (CW) mode can provide high peak current as well as the high average current which are required for many advanced applications of accelerators facilities, for example, electron coolers for hadron beams, electron-ion colliders, and Free-Electron Lasers (FELs). Superconducting Radio Frequency (SRF) has many advantages over other electron-injector technologies, especially when it is working in CW mode as it offers higher repetition rate. An 112 MHz SRF electron photo-injector (gun) was developed at Brookhaven National Laboratory (BNL) to produce high-brightness and high-bunch-charge bunches for electron cooling experiments. The gun utilizes a Quarter-Wave Resonator (QWR) geometry for a compact structure and improved electron beam dynamics. The detailed RF design of the cavity, fundamental coupler and cathode stalk are presented in this work. A GPU accelerated code was written to improve the speed of simulation of multipacting, an important hurdle the SRF structure has to overcome in various locations. The injector utilizes high Quantum Efficiency (QE) multi-alkali photocathodes (K2CsSb) for generating electrons. The cathode fabrication system and procedure are also included in the thesis. Beam dynamic simulation of the injector was done with the code ASTRA. To find the optimized parameters of the cavities and beam optics, the author wrote a genetic algorithm Python script to search for the best solution in this high-dimensional parameter space. The gun was successfully commissioned and produced world record bunch charge and average current in an SRF photo-injector.

  16. Tip-based electron source for femtosecond electron diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Stein, Jan-Paul; Hoffrogge, Johannes; Schenk, Markus; Krueger, Michael; Baum, Peter; Hommelhoff, Peter [Max-Planck-Institut fuer Quantenoptik, Hans-Kopfermann-Strasse 1, 85748 Garching bei Muenchen (Germany)

    2012-07-01

    Illumination of a sharp tungsten tip with femtosecond laser pulses leads to the emission of ultrashort, high brightness electron pulses that are ideally suited for ultrafast electron diffraction (UED) experiments [1]. The tip's small virtual source size ({proportional_to}5 nm) results in a large transverse coherence length of the electron pulse and therefore better spatial resolution as compared to a conventional flat cathode design. The enhanced electric field at the tip apex (2 GV/m) is about two orders of magnitude larger than the maximum electric field applicable in a plate capacitor based setup (20 MV/m). This reduces the influence of the initial energy distribution on the pulse duration at the target and improves the timing jitter. Simulations show that a setup with a sharp tip as the cathode in combination with two anodes yields an electron pulse duration of about 50 fs at the sample. The electron energy is 30 keV and the gun to sample distance is 3 cm. We implemented the two anode setup with the tip experimentally. We present the experimental characteristics of the emitted electron beam both in static field emission and in laser triggered emission.

  17. Femtosecond electron bunches, source and characterization

    Energy Technology Data Exchange (ETDEWEB)

    Thongbai, C. [FNRF, Department of Physics, Chiang Mai University, Chiangmai 50200 (Thailand)], E-mail: chlada@chiangmai.ac.th; Kusoljariyakul, K. [FNRF, Department of Physics, Chiang Mai University, Chiangmai 50200 (Thailand); Rimjaem, S. [DESY Zeuthen, Platanenallee 6, Zeuthen 15738 (Germany); Rhodes, M.W. [IST, Chiang Mai University, Chiangmai 50200 (Thailand); Saisut, J. [FNRF, Department of Physics, Chiang Mai University, Chiangmai 50200 (Thailand); Thamboon, P.; Wichaisirimongkol, P. [IST, Chiang Mai University, Chiangmai 50200 (Thailand); Vilaithong, T. [FNRF, Department of Physics, Chiang Mai University, Chiangmai 50200 (Thailand)

    2008-03-11

    A femtosecond electron source has been developed at the Fast Neutron Research Facility (FNRF), Chiang Mai University, Thailand. So far, it has produced electron bunches as short as {sigma}{sub z}{approx}180 fs with (1-6)x10{sup 8} electrons per microbunch. The system consists of an RF-gun with a thermionic cathode, an alpha-magnet as a magnetic bunch compressor, and a linear accelerator as a post acceleration section. Coherent transition radiation emitted at wavelengths equal to and longer than the bunch length is used in a Michelson interferometer to determine the bunch length by autocorrelation technique. The experimental setup and results of the bunch length measurement are described.

  18. A Monte Carlo approach to electron contamination sources in the Saturne-25 and -41

    Energy Technology Data Exchange (ETDEWEB)

    Malataras, G.; Kappas, C. [Medical Physics Department, School of Medicine, University of Patras, Patras, Hellas (Greece)]. E-mail: kappas@med.upatras.gr; Lovelock, D.M.J. [Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York City, NY (United States)

    2001-09-01

    The various components of the accelerator treatment head act as sources of contaminating electrons. The presence of contamination electrons increases the surface dose, which deteriorates the skin-sparing effect. The present study examines the sources of this 'contamination', the influence on the surface dose and the shape of the build-up curve. The Monte Carlo simulation of two linear accelerators, Saturne-25 and -41, allowed us to study the influence of electron contamination in various therapeutic energies and in different geometries. The Saturne-25 and -41 cover a wide range of therapeutic energies with nominal energies 12/23 MV and 6/15 MV, respectively. The analysis of the results shows that at a source-to-surface distance of 100 cm and a wide opening of the collimators, the main sources of contaminating electrons are the flattening filter and the air below it. The contribution of the secondary contamination electrons on the surface dose is 16% for 6 MV and 12 MV, 6% for 15 MV and 17% for 23 MV. The energy spectra of electrons coming from the flattening filter and the air below it are completely different. The air produces electrons of low energies. The mean energies of these spectra vary from 1 MeV to 2 MeV depending on the nominal energy of the photon beam. The secondary electrons generated by the flattening filter produce a wide energy spectrum with mean energies of the same order of the bremsstrahlung spectrum. The flattening filter absorbs the secondary electrons generated in the target, the primary collimator and the air inside the head. (author)

  19. A Monte Carlo approach to electron contamination sources in the Saturne-25 and -41

    Science.gov (United States)

    Malataras, G.; Kappas, C.; Lovelock, D. M. J.

    2001-09-01

    The various components of the accelerator treatment head act as sources of contaminating electrons. The presence of contamination electrons increases the surface dose, which deteriorates the skin-sparing effect. The present study examines the sources of this `contamination', the influence on the surface dose and the shape of the build-up curve. The Monte Carlo simulation of two linear accelerators, Saturne-25 and -41, allowed us to study the influence of electron contamination in various therapeutic energies and in different geometries. The Saturne-25 and -41 cover a wide range of therapeutic energies with nominal energies 12/23 MV and 6/15 MV, respectively. The analysis of the results shows that at a source-to-surface distance of 100 cm and a wide opening of the collimators, the main sources of contaminating electrons are the flattening filter and the air below it. The contribution of the secondary contamination electrons on the surface dose is 16% for 6 MV and 12 MV, 6% for 15 MV and 17% for 23 MV. The energy spectra of electrons coming from the flattening filter and the air below it are completely different. The air produces electrons of low energies. The mean energies of these spectra vary from 1 MeV to 2 MeV depending on the nominal energy of the photon beam. The secondary electrons generated by the flattening filter produce a wide energy spectrum with mean energies of the same order of the bremsstrahlung spectrum. The flattening filter absorbs the secondary electrons generated in the target, the primary collimator and the air inside the head.

  20. Development of the 3MeV RFQ for the Compact Pulsed Hadron Source at Tsinghua University

    CERN Document Server

    Xing, Q Z; Cai, J C; Guan, X; Wang, X W; Wei, J; Xiong, Z F; Zhang, H Y; Billen, J H; Young, L M; Guan, W Q; He, Y; Li, J; Stovall, J

    2010-01-01

    We pre­sent, in this paper, the physics and me­chan­i­cal de­sign of a Radio Fre­quen­cy Quadrupole (RFQ) ac­cel­er­a­tor for the Com­pact Pulsed Hadron Source (CPHS) at Ts­inghua Uni­ver­si­ty. The 3-me­ter-long RFQ will ac­cel­er­ate pro­tons from 50 keV to 3 MeV at an RF fre­quen­cy of 325 MHz. In the physics de­sign we have pro­grammed the in­ter-vane volt­age as a func­tion of beam ve­loc­i­ty, to op­ti­mize the per­for­mance of the RFQ, by tai­lor­ing the cav­i­ty cross sec­tion and vane-tip ge­om­e­try as a func­tion of lon­gi­tu­di­nal po­si­tion while lim­it­ing the peak sur­face elec­tric field to 1.8 Kil­patrick. There will be no Medi­um-En­er­gy-Beam-Trans­port (MEBT) fol­low­ing the RFQ. The fo­cus­ing at the high en­er­gy end of the RFQ and at the en­trance of the DTL have been tai­lored to pro­vide con­tin­u­ous restor­ing forces in­de­pen­dent of the beam cur­rent. In sim­u­la­tions of the pro­ton beam in the RFQ, ...

  1. Calculation of SF6-/SF6 and Cl-/CFCl3 electron attachment cross sections in the energy range 0-100 meV

    Science.gov (United States)

    Chutjian, A.

    1982-01-01

    Electron attachment cross sections for the processes SF6-/SF6 and Cl-/CFCl3 are calculated in a local theory using a model in which diatomic-like potential energy curves for the normal modes are constructed from available spectroscopic data. Thermally populated vibrational and rotational levels are included. Good agreement is found with experimental cross sections in the energy range 5-100 meV for a particular choice of potential energy curve parameters.

  2. Development of polystyrene calorimeter for application at electron energies down to 1.5 MeV

    DEFF Research Database (Denmark)

    Miller, A.; Kovacs, A.; Kuntz, F.

    2002-01-01

    Polystyrene (PS) calorimeters developed at Riso National Laboratory for use below 4 MeV have been modified due to irradiation technology requirements concerning both design principles and dimensions. The temperature-time relationship after irradiation was measured, and two ways of dose measurement...

  3. A high current, short pulse electron source for wakefield accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Ho, Ching-Hung

    1992-12-31

    Design studies for the generation of a high current, short pulse electron source for the Argonne Wakefield Accelerator are presented. An L-band laser photocathode rf gun cavity is designed using the computer code URMEL to maximize the electric field on the cathode surface for fixed frequency and rf input power. A new technique using a curved incoming laser wavefront to minimize the space charge effect near the photocathode is studied. A preaccelerator with large iris to minimize wakefield effects is used to boost the drive beam to a useful energy of around 20 MeV for wakefield acceleration experiments. Focusing in the photocathode gun and the preaccelerator is accomplished with solenoids. Beam dynamics simulations throughout the preaccelerator are performed using particle simulation codes TBCI-SF and PARMELA. An example providing a useful set of operation parameters for the Argonne Wakefield Accelerator is given. The effects of the sagitta of the curved beam and laser amplitude and timing jitter effects are discussed. Measurement results of low rf power level bench tests and a high power test for the gun cavity are presented and discussed.

  4. A high current, short pulse electron source for wakefield accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Ho, Ching-Hung.

    1992-01-01

    Design studies for the generation of a high current, short pulse electron source for the Argonne Wakefield Accelerator are presented. An L-band laser photocathode rf gun cavity is designed using the computer code URMEL to maximize the electric field on the cathode surface for fixed frequency and rf input power. A new technique using a curved incoming laser wavefront to minimize the space charge effect near the photocathode is studied. A preaccelerator with large iris to minimize wakefield effects is used to boost the drive beam to a useful energy of around 20 MeV for wakefield acceleration experiments. Focusing in the photocathode gun and the preaccelerator is accomplished with solenoids. Beam dynamics simulations throughout the preaccelerator are performed using particle simulation codes TBCI-SF and PARMELA. An example providing a useful set of operation parameters for the Argonne Wakefield Accelerator is given. The effects of the sagitta of the curved beam and laser amplitude and timing jitter effects are discussed. Measurement results of low rf power level bench tests and a high power test for the gun cavity are presented and discussed.

  5. Post-focus expansion of ion beams for low fluence and large area MeV ion irradiation: Application to human brain tissue and electronics devices

    Science.gov (United States)

    Whitlow, Harry J.; Guibert, Edouard; Jeanneret, Patrick; Homsy, Alexandra; Roth, Joy; Krause, Sven; Roux, Adrien; Eggermann, Emmanuel; Stoppini, Luc

    2017-08-01

    Irradiation with ∼3 MeV proton fluences of 106-109 protons cm-2 have been applied to study the effects on human brain tissue corresponding to single-cell irradiation doses and doses received by electronic components in low-Earth orbit. The low fluence irradiations were carried out using a proton microbeam with the post-focus expansion of the beam; a method developed by the group of Breese [1]. It was found from electrophysiological measurements that the mean neuronal frequency of human brain tissue decreased to zero as the dose increased to 0-1050 Gy. Enhancement-mode MOSFET transistors exhibited a 10% reduction in threshold voltage for 2.7 MeV proton doses of 10 Gy while a NPN bipolar transistor required ∼800 Gy to reduce the hfe by 10%, which is consistent the expected values.

  6. 6 MeV electron irradiation effects on electrical properties of Al/TiO{sub 2}/n-Si MOS capacitors

    Energy Technology Data Exchange (ETDEWEB)

    Laha, P. [Department of Applied Physics, Birla Institute of Technology, Mesra, Ranchi 835215 (India); Dahiwale, S.S. [Department of Physics, University of Pune, Pune 411007 (India); Banerjee, I. [Department of Applied Physics, Birla Institute of Technology, Mesra, Ranchi 835215 (India); Pabi, S.K. [Department of Metallurgical and Material Engineering, Indian Institute of Technology, Kharagpur 721302 (India); Kimd, D. [Department of Material Science and Engineering, Korea University, Seoul (Korea, Republic of); Barhai, P.K. [Department of Applied Physics, Birla Institute of Technology, Mesra, Ranchi 835215 (India); Bhoraskar, V.N. [Department of Physics, University of Pune, Pune 411007 (India); Mahapatra, S.K., E-mail: skmahapatra@bitmesra.ac.in [Department of Applied Physics, Birla Institute of Technology, Mesra, Ranchi 835215 (India)

    2011-12-01

    Highlights: {yields} The electron irradiation effects make variation in the device parameters. {yields} The device parameters changes due to percentage of defects and charge trapping. {yields} Leakage current of Al/TiO{sub 2}/n-Si changes due to interface dangling bonds. {yields} The leakage current mechanism of MOS structures is due to Poole-Frenkel effect. - Abstract: The irradiation effects of 6 MeV electrons on the electrical properties of Al/TiO{sub 2}/n-Si metal-oxide-semiconductor capacitors have been investigated. Nine Al/TiO{sub 2}/n-Si capacitors were fabricated using radio frequency magnetron sputtering and divided into three groups. Groups were irradiated with 6 MeV electrons at 10, 20, and 30 kGy doses, respectively, keeping the dose rate {approx}1 kGy/min. The variations in the capacitance-voltage and leakage current-voltage characteristics, in addition to the electrical parameters, such as conductance (G/{omega}), flat-band voltage, interface trap density and the surface charge density with electron dose were studied. The Poole-Frenkel coefficient of the MOS capacitors was determined from current-voltage characteristics. Possible mechanisms for the enhanced leakage current in the electron irradiated MOS capacitors are discussed.

  7. The CLIC electron and positron polarized sources

    CERN Document Server

    Rinolfi, Louis; Bulyak, Eugene; Chehab, Robert; Dadoun, Olivier; Gai, Wei; Gladkikh, Peter; Kamitani, Takuya; Kuriki, Masao; Liu, Wanming; Maryuama, Takashi; Omori, Tsunehiko; Poelker, Matt; Sheppard, John; Urakawa, Junji; Variola, Alessandro; Vivoli, Alessandro; Yakimenko, Vitaly; Zhou, Feng; Zimmermann, Frank

    2010-01-01

    The CLIC polarized electron source is based on a DC gun where the photocathode is illuminated by a laser beam. Each micro-bunch has a charge of 6x109 e−, a width of 100 ps and a repetition rate of 2 GHz. A peak current of 10 A in the micro-bunch is a challenge for the surface charge limit of the photo-cathode. Two options are feasible to generate the 2 GHz e− bunch train: 100 ps micro-bunches can be extracted from the photo-cathode either by a 2 GHz laser system or by generating a macro-bunch using a ~200 ns laser pulse and a subsequent RF bunching system to produce the appropriate micro-bunch structure. Recent results obtained by SLAC, for the latter case, are presented. The polarized positron source is based on a positron production scheme in which polarized photons are produced by a laser Compton scattering process. The resulting circularly-polarized gamma photons are sent onto a target, producing pairs of longitudinally polarized electrons and positrons. The Compton backscattering process occurs eithe...

  8. An electromagnetically focused electron beam line source

    Science.gov (United States)

    Iqbal, Munawar; Masood, Khalid; Rafiq, Mohammad; Chaudhary, Maqbool A.; Aleem, Fazal-e.-

    2003-11-01

    A directly heated thermionic electron beam source was constructed. A tungsten wire of length 140 mm with diameter 0.9 mm was used as a cathode. An emission current of 5000 mA was achieved at an input heating power of 600 W. Cathode to anode distance of 6 mm with acceleration voltage of 10 kV was used. A uniform external magnetic field of 50 G was employed to obtain a well-focused electron beam at a deflection of 180°, with cathode to work site distance of 130 mm. Dimensions of the beam (1.25×120 mm) recorded at the work site were found to be in good agreement with the designed length of cathode. The deformation of the cathode was overcome by introducing a spring action mechanism, which gives uniform emission current density throughout the emission surface. We have achieved the saturation limit of the designed source resulting in smooth and swift operation of the gun for many hours (10-15 h continuously). The design of gun is so simple that it can accommodate longer cathodes for obtaining higher emission values. This gun has made it possible to coat large substrate surfaces at much faster evaporation rate at lower cost. It can also be useful in large-scale vacuum metallurgy plants for melting, welding and heat treatment.

  9. Demonstration of single-shot picosecond time-resolved MeV electron imaging using a compact permanent magnet quadrupole based lens

    CERN Document Server

    Cesar, D; Musumeci, P; Sun, Y; Harrison, J; Frigola, P; O'Shea, F H; To, H; Alesini, D; Li, R K

    2016-01-01

    We present the results of an experiment where a short focal length (~ 1.3 cm) permanent magnet electron lens is used to image micron-size features of a metal sample in a single shot, using an ultra- high brightness ps-long 4 MeV electron beam from a radiofrequency photoinjector. Magnifcation ratios in excess of 30x were obtained using a triplet of compact, small gap (3.5 mm), Halbach-style permanent magnet quadrupoles with nearly 600 T/m field gradients. These results pave the way to- wards single shot time-resolved electron microscopy and open new opportunities in the applications of high brightness electron beams.

  10. Near-real time forecasts of MeV protons based on sub-relativistic electrons: communicating the outputs to the end users

    Science.gov (United States)

    Sarlanis, Christos; Heber, Bernd; Labrenz, Johannes; Kühl, Patrick; Marquardt, Johannes; Dimitroulakos, John; Papaioannou, Athanasios; Posner, Arik

    2017-04-01

    Solar Energetic Particle (SEP) events are one of the most important elements of space weather. Given that the complexity of the underlying physical processes of the acceleration and propagation of SEP events is still a very active research area, the prognosis of SEP event occurrence and their corresponding characteristics remains challenging. In order to provide up to an hour warning time before these particles arrive at Earth, relativistic electron and below 50 MeV proton data from the Electron Proton Helium Instrument (EPHIN) on SOHO were used to implement the 'Relativistic Electron Alert System for Exploration (REleASE)'. The REleASE forecasting scheme was recently rewritten in the open access programming language PYTHON and will be made publicly available. As a next step, along with relativistic electrons (v > 0.9 c) provided by SOHO, near-relativistic (v innovation programme under grant agreement No 637324.

  11. Uranium target for electron accelerator based neutron source for BNCT

    Science.gov (United States)

    Tonchev, A. P.; Harmon, F.; Collens, T. J.; Kennedy, K.; Sabourov, A.; Harker, Y. D.; Nigg, D. W.; Jones, J. L.

    2001-07-01

    Calculations of the epithermal-neutron yield of photoneutrons from a uranium-beryllium converter using a 27 MeV electron linear accelerator have been investigated. In this concept, relativistic electron beams from a 30 MeV LINAC impinge upon a small uranium sphere surrounded by a cylindrical tank of circulating heavy water (D2O) nested in a beryllium cube. The photo-fission neutron spectrum from the uranium sphere is thermalized in deuterium and beryllium, filtered and moderated in special material (AlF3/Al/LiF), and directed to the patient. The results of these calculations demonstrate that photoneutron devices could offer a promising alternative to nuclear reactors for the production of epithermal neutrons for Neutron Capture Therapy. The predicted parameter for the epithermal flux is more than 108n.cm-2.mA-1.

  12. Midrapidity source of intermediate-mass fragments in highly central collisions of Au + Au at 150 A MeV

    Energy Technology Data Exchange (ETDEWEB)

    Alard, J.P.; Basrak, Z.; Bastid, N.; Belayev, I.M.; Bini, M.; Blaich, T.; Bock, R.; Buta, A.; Caplar, R.; Cerruti, C.; Cindro, N.; Coffin, J.P.; Crouau, M.; Dupieux, P.; Eroe, J.; Fan, Z.G.; Fintz, P.; Fodor, Z.; Freifelder, R.; Fraysse, L.; Frolov, S.; Gobbi, A.; Grigorian, Y.; Guillaume, G.; Herrmann, N.; Hildenbrand, K.D.; Hoelbling, S.; Houari, O.; Jeong, S.C.; Jorio, M.; Jundt, F.; Kecskemeti, J.; Koncz, P.; Korchagin, Y.; Kotte, R.; Kraemer, M.; Kuhn, C.; Legrand, I.; Lebedev, A.; Maguire, C.; Manko, V.; Matulewicz, T.; Mgebrishvili, G.; Moesner, J.; Moisa, D.; Montarou, G.; Morel, P.; Neubert, W.; Olmi, A.; Pasquali, G.; Pelte, D.; Petrovici, M.; Poggi, G.; Rami, F.; Reisdorf, W.; Sadchikov, A.; Schuell, D.; Seres, Z.; Sikora, B.; Simion, V.; Smolyankin, S.; Sodan, U.; Taccetti, N.; Teh, K.; Tezkratt, R.; Trzaska, M.; Vasiliev, M.A.; Wagner, P.; Wessels, J.P.; Wienold, T.; Wilhelmi, Z.; Wohlfarth, D.; Zhilin, A.V. (Institute for Physics and Nuclear Engineering, Bucharest (Romani

    1992-08-10

    Charged particles have been observed in collisions of Au on Au at an incident energy of 150{ital A} MeV using a high-granularity detector system covering approximately the forward hemisphere in the center-of-mass system. Highly central collisions have been studied using a double selection criterion which combines large charged-particle multiplicities with small transverse-momentum directivities. In this class of events about one quarter of the total nuclear charge emerges as intermediate-mass fragments with nuclear charges {ital Z}{gt}2. These fragments are centered at midrapidity and are produced with large transverse velocities.

  13. Midrapidity source of intermediate-mass fragments in highly central collisions of Au + Au at 150A MeV

    Science.gov (United States)

    Alard, J. P.; Basrak, Z.; Bastid, N.; Belayev, I. M.; Bini, M.; Blaich, Th.; Bock, R.; Buta, A.; Čaplar, R.; Cerruti, C.; Cindro, N.; Coffin, J. P.; Crouau, M.; Dupieux, P.; Erö, J.; Fan, Z. G.; Fintz, P.; Fodor, Z.; Freifelder, R.; Fraysse, L.; Frolov, S.; Gobbi, A.; Grigorian, Y.; Guillaume, G.; Herrmann, N.; Hildenbrand, K. D.; Hölbling, S.; Houari, O.; Jeong, S. C.; Jorio, M.; Jundt, F.; Kecskemeti, J.; Koncz, P.; Korchagin, Y.; Kotte, R.; Krämer, M.; Kuhn, C.; Legrand, I.; Lebedev, A.; Maguire, C.; Manko, V.; Matulewicz, T.; Mgebrishvili, G.; Mösner, J.; Moisa, D.; Montarou, G.; Morel, P.; Neubert, W.; Olmi, A.; Pasquali, G.; Pelte, D.; Petrovici, M.; Poggi, G.; Rami, F.; Reisdorf, W.; Sadchikov, A.; Schüll, D.; Seres, Z.; Sikora, B.; Simion, V.; Smolyankin, S.; Sodan, U.; Taccetti, N.; Teh, K.; Tezkratt, R.; Trzaska, M.; Vasiliev, M. A.; Wagner, P.; Wessels, J. P.; Wienold, T.; Wilhelmi, Z.; Wohlfarth, D.; Zhilin, A. V.

    1992-08-01

    Charged particles have been observed in collisions of Au on Au at an incident energy of 150A MeV using a high-granularity detector system covering approximately the forward hemisphere in the center-of-mass system. Highly central collisions have been studied using a double selection criterion which combines large charged-particle multiplicities with small transverse-momentum directivities. In this class of events about one quarter of the total nuclear charge emerges as intermediate-mass fragments with nuclear charges Z>2. These fragments are centered at midrapidity and are produced with large transverse velocities.

  14. LINAC4 - Views of the 3 MeV Front-end (H- Source, LEBT, RFQ, MEBT) with Test Bench.

    CERN Multimedia

    Anna Pantelia

    2013-01-01

    The Linac4 is the new linear accelerator that will replace Linac2 as proton low energy injector in the LHC accelerator chain. On 14 November, members of the Linac4 collaboration and the CERN Operation Group were brought together for their first “real day” in the Linac4 Control Room. Together, they successfully accelerated their first hydrogen ion beam to 3 MeV. It was an exciting moment for everyone involved marked the start of one of the most critical commissioning phases for the new accelerator.

  15. 2 MeV electron irradiation effects on bulk and interface of atomic layer deposited high-k gate dielectrics on silicon

    Energy Technology Data Exchange (ETDEWEB)

    García, H., E-mail: hecgar@ele.uva.es [Departamento de Electricidad y Electrónica, ETSI Telecomunicación, Universidad de Valladolid, 47011 Valladolid (Spain); Castán, H.; Dueñas, S.; Bailón, L. [Departamento de Electricidad y Electrónica, ETSI Telecomunicación, Universidad de Valladolid, 47011 Valladolid (Spain); Campabadal, F.; Rafí, J.M.; Zabala, M.; Beldarrain, O. [Institut de Microelectrònica de Barcelona (IMB-CNM), CSIC, Campus UAB, 08193 Bellaterra (Spain); Ohyama, H.; Takakura, K.; Tsunoda, I. [Department of Electronic Engineering, Kumamoto National College of Technology, Kumamoto 861-1102 (Japan)

    2013-05-01

    2 MeV electron irradiation effects on the electrical properties of Al{sub 2}O{sub 3} and HfO{sub 2}-based metal–insulator–semiconductor capacitors have been studied. High-k dielectrics were directly grown on silicon by atomic layer deposition. Capacitors were exposed to three different electron irradiation doses of 0.025, 0.25 and 2.5 MGy. Capacitance–voltage, deep-level transient spectroscopy, conductance transients, flat-band voltage transients and current–voltage techniques were used to characterize the defects induced or activated by irradiation on the dielectric bulk and on the interface with silicon substrate. In all cases, positive charge is trapped in the dielectric bulk after irradiation indicating the existence of hole traps in the dielectric. When the samples are exposed to 2 MeV electron beam (e-beam) irradiation, electron–hole pairs are created and holes are then captured by the hole traps. Insulator/semiconductor interface quality slightly improves for low irradiation doses, but it is degraded for high doses. Irradiation always degrades the dielectric layers in terms of gate leakage current: the trapped holes are mobile charge which can contribute to leakage current by hopping from trap to trap. - Highlights: ► Positive charge accumulates inside dielectrics after electron irradiation. ► Irradiation improves oxide/semiconductor interface for low doses. ► Irradiation increases gate leakage current.

  16. Effect of fission fragment on thermal conductivity via electrons with an energy about 0.5 MeV in fuel rod gap

    Directory of Open Access Journals (Sweden)

    F Golian

    2017-02-01

    Full Text Available The heat transfer process from pellet to coolant is one of the important issues in nuclear reactor. In this regard, the fuel to clad gap and its physical and chemical properties are effective factors on heat transfer in nuclear fuel rod discussion. So, the energy distribution function of electrons with an energy about 0.5 MeV in fuel rod gap in Busherhr’s VVER-1000 nuclear reactor was investigated in this paper. Also, the effect of fission fragments such as Krypton, Bromine, Xenon, Rubidium and Cesium on the electron energy distribution function as well as the heat conduction via electrons in the fuel rod gap have been studied. For this purpose, the Fokker- Planck equation governing the stochastic behavior of electrons in absorbing gap element has been applied in order to obtain the energy distribution function of electrons. This equation was solved via Runge-Kutta numerical method. On the other hand, the electron energy distribution function was determined by using Monte Carlo GEANT4 code. It was concluded that these fission fragments have virtually insignificant effect on energy distribution of electrons and therefore, on thermal conductivity via electrons in the fuel to clad gap. It is worth noting that this result is consistent with the results of other experiments. Also, it is shown that electron relaxation in gap leads to decrease in thermal conductivity via electrons

  17. Improvement of dose distribution in phantom by using epithermal neutron source based on the Be(p,n) reaction using a 30 MeV proton cyclotron accelerator.

    Science.gov (United States)

    Tanaka, H; Sakurai, Y; Suzuki, M; Takata, T; Masunaga, S; Kinashi, Y; Kashino, G; Liu, Y; Mitsumoto, T; Yajima, S; Tsutsui, H; Takada, M; Maruhashi, A; Ono, K

    2009-07-01

    In order to generate epithermal neutrons for boron neutron capture therapy (BNCT), we proposed the method of filtering and moderating fast neutrons, which are emitted from the reaction between a beryllium target and 30 MeV protons accelerated by a cyclotron, using an optimum moderator system composed of iron, lead, aluminum, calcium fluoride, and enriched (6)LiF ceramic filter. At present, the epithermal-neutron source is under construction since June 2008 at Kyoto University Research Reactor Institute. This system consists of a cyclotron to supply a proton beam of about 1 mA at 30 MeV, a beam transport system, a beam scanner system for heat reduction on the beryllium target, a target cooling system, a beam shaping assembly, and an irradiation bed for patients. In this article, an overview of the cyclotron-based neutron source (CBNS) and the properties of the treatment neutron beam optimized by using the MCNPX Monte Carlo code are presented. The distribution of the RBE (relative biological effectiveness) dose in a phantom shows that, assuming a (10)B concentration of 13 ppm for normal tissue, this beam could be employed to treat a patient with an irradiation time less than 30 min and a dose less than 12.5 Gy-eq to normal tissue. The CBNS might be an alternative to the reactor-based neutron sources for BNCT treatments.

  18. Estimate of the radiation source term for 18F production via thick H218O targets bombarded with 18 MeV protons

    Science.gov (United States)

    Cruzate, Juan Ángel

    2015-12-01

    The positron-emitting radionuclide most important from the point of view of radiation protection is 18F. This isotope is usually produced by bombarding 18O-enriched water with protons. Currently there are few experimental data on the radiation source term generated during these reactions. In addition, presently there is no theoretical estimates of this source term, for use in radiation protection, validated by experimental data. Up till now this term is calculated by using nuclear interactions' simulation codes, such as ALICE91. An estimate of the energy spectra for neutrons and photons, induced by 18 MeV protons on H218O target, have been calculated by using MCNPX code with cross sections from release 0 of ENDF/B VII library for all materials except 18O, for which TENDL-2012 library was used. This estimate was validated against a recent experiment carried out at the Japan Atomic Energy Agency (JAEA). The calculated spectra have generally well reproduced experiments. The results show that the calculated radiation source term may be used to estimate the neutron activation of the accelerator components and the cyclotron building, to calculate the cyclotron shielding, and to carry out radiation protection evaluations in general, for the case of cyclotrons producing 18F by means of the 18O(p,n)18F nuclear reactions, for proton energies up to 18 MeV.

  19. Modeling the effect of 1 MeV electron irradiation on the performance of n+-p-p+ silicon space solar cells

    Science.gov (United States)

    Hamache, Abdelghani; Sengouga, Nouredine; Meftah, Afak; Henini, Mohamed

    2016-06-01

    Energetic particles such as electrons and protons induce severe degradation on the performance of solar cells used to power satellites and space vehicles. This degradation is usually attributed to lattice damage in the active region of the solar cell. One of the phenomena observed in silicon solar cells exposed to 1 MeV electron irradiation is the anomalous degradation of the short circuit current. It initially decreases followed by a recovery before falling again with increasing electron fluence. This behavior is usually attributed to type conversion of the solar cell active region. The other figures of merit, on the other hand, decrease monotonically. In this work numerical simulator SCAPS (Solar Cell Capacitance Simulator) is used to elucidate this phenomenon. The current-voltage characteristics of a Si n+-p-p+ structure are calculated under air mass zero spectrum with the fluence of 1 MeV electrons as a variable parameter. The effect of irradiation on the solar cell is simulated by a set of defects of which the energy levels lie deep in energy gap of silicon (much larger than the characteristic thermal energy kT far from either the conduction or valence band). Although several types of deep levels are induced by irradiation including deep donors (exchange electrons mainly with the conduction band), deep acceptors (exchange electrons mainly with the valence band) and/or generation-recombination centers (exchange electrons with both the conduction and valence bands), it was found that, only one of them (the shallowest donor) is responsible for the anomalous degradation of the short circuit current. It will be also shown, by calculating the free charge carrier profile in the active region, that this behavior is not related to type conversion but to a lateral widening of the space charge region.

  20. Low level radio frequency system of 15-MeV electrons linac%15-MeV电子直线加速器的低电平系统

    Institute of Scientific and Technical Information of China (English)

    张俊强; 刘亚娟; 钟少鹏; 李林; 李英民; 顾强

    2016-01-01

    Background: The photo-neutron source driven by 15-MeV electrons linac in Thorium molten salt reactor (TMSR) program was designed for nuclear data measurement.Purpose:To ensure the linac to provide stable and high quality beam bunches, a low level radio frequency (LLRF) control system based on field programmable gate array (FPGA) was developed.Methods: LLRF realized digital amplitude and phase feedback control by using up-down converter, IQ (In-phase and Quadrature) modulator and demodulator techniques.Results: After commission, the control accuracy of amplitude and phase is less than ±0.4% and ±0.6o, respectively.Conclusion: Long time running indicates that the whole digital control loop has the properties of fast time response and good stability, which meets the demand of photo-neutron facility.%15-MeV电子加速器驱动的光中子源装置(TMSR Photo-Neutron Source Phase 1,TPNS1)是专为钍基熔盐堆(Thorium Molten Salt Reactor,TMSR)核数据测量设计和建造的.为保证直线加速器提供稳定的、高品质的束流,开发了基于可编程逻辑门阵列(Field Programmable Gate Array,FPGA)技术的低电平控制系统,利用上下变频、IQ(In-phase and Quadrature)调制解调技术实现了直线加速器幅度和相位的反馈控制.经测试,幅度和相位的控制精度达到±0.4%,可达±0.6°.长时间的运行表明,整个数字化环路的响应时间快,稳定性好,满足中子源装置的运行要求.

  1. An open-source laser electronics suite

    Science.gov (United States)

    Pisenti, Neal C.; Reschovsky, Benjamin J.; Barker, Daniel S.; Restelli, Alessandro; Campbell, Gretchen K.

    2016-05-01

    We present an integrated set of open-source electronics for controlling external-cavity diode lasers and other instruments in the laboratory. The complete package includes a low-noise circuit for driving high-voltage piezoelectric actuators, an ultra-stable current controller based on the design of, and a high-performance, multi-channel temperature controller capable of driving thermo-electric coolers or resistive heaters. Each circuit (with the exception of the temperature controller) is designed to fit in a Eurocard rack equipped with a low-noise linear power supply capable of driving up to 5 A at +/- 15 V. A custom backplane allows signals to be shared between modules, and a digital communication bus makes the entire rack addressable by external control software over TCP/IP. The modular architecture makes it easy for additional circuits to be designed and integrated with existing electronics, providing a low-cost, customizable alternative to commercial systems without sacrificing performance.

  2. Mechanical and thermal properties and morphological studies of 10 MeV electron beam irradiated LDPE/hydroxyapatite nano-composite

    Science.gov (United States)

    Soltani, Z.; Ziaie, F.; Ghaffari, M.; Afarideh, H.; Ehsani, M.

    2013-02-01

    In this work the nano-composite samples were prepared using the LDPE filled with different weight percentages of hydroxyapatite powder which was synthesized via hydrolysis method. The samples were subjected to irradiation under 10 MeV electron beam in 75-250 kGy doses. Mechanical and thermal properties as well as the morphology of the nano-composite samples were investigated and compared. The hot-set and swelling tests confirmed the radiation crosslinking induced in the polymer matrix especially between the matrix and reinforcement phase. The result indicates that the mechanical and thermal parameters are strongly dependent on the hydroxyapatite content in comparison to radiation.

  3. Observational Possibility of the Early GRBs using a Gaseous Electron Tracking Compton Camera in sub-MeV and MeV regions

    Science.gov (United States)

    Tanimori, Toru

    2010-10-01

    GRBs have been recently known as a unique probe to catch the highest z galaxies and stars. Here I propose the new trigger method to catch high-z GRBs with z>10 efficiently by imaging sub-MeV gamma rays from GRBs. We have developed the Electron Tracking Compton Camera (ETCC) with reconstructing tracks of the recoil electron in Compton process to explore the MeV gamma-ray astronomy. By measuring the track of a recoil electron, the direction of the incident gamma ray is determined for each photon, which enables us to reconstruct the direction of GRBs by detecting only several ten photons (>100 keV). Ability of the large ETCC (100 cm2 effective area) to detect GRBs with z~20 is revealed, based on the results of the balloon experiment and laboratory imaging test using the small ETCC.

  4. Asymmetry in generation of near-surface X-rays by 33 MeV electrons at grazing interaction with a thin Si plate in magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Kaplin, V.V., E-mail: kaplin@tpu.ru

    2015-07-15

    Recently observed effect of an asymmetry in X-ray generation by 33 MeV electrons in a 50 μm Si plate oriented along an internal beam of a betatron is described. The evolution of angular patterns formed by the X-rays generated in the Si plate having a length of 4 mm along the electron beam direction, when changing the plate orientation relative to the electron beam, is presented. The experimental results showed for the first time preferential generation of X-rays on the Si plate surface, which was external with respect to the center of the accelerator. At grazing incidence of electrons on this surface the radiation was emitted along the Si plate surface in the cone, which was several times narrower than the cone of ordinary bremsstrahlung emitted along electron beam direction. At grazing interaction of electrons with the internal Si plate surface facing towards the center of the accelerator, the generation of the near-surface radiation was not observed. It is supposed that the presence of the magnetic field of accelerator is decisive for the formation of the observed effect of asymmetry in X-ray generation by electrons in the long Si plate because of possible realization on external plate surface a “magneto-crystalline undulator” regime of near-surface electron motion.

  5. Evaluation of the relative effectiveness of LiF-based TL detectors for electron radiotherapy beams over the energy range 6-20 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Nahajowski, D.; Gora, E.; Rozwadowska-Bogusz, B.; Lesiak, J.; Polak, B.; Kabat, D.; Zawadzki, P. [Centre of Oncology, Maria Sklodowska-Curie Memorial Institute, Krakow Branch, Garncarska 11, 31-115 Krakow (Poland); Waligorski, M.P.R. [Centre of Oncology, Maria Sklodowska-Curie Memorial Institute, Krakow Branch, Garncarska 11, 31-115 Krakow (Poland); Institute of Nuclear Physics, Polish Academy of Sciences (IFJ PAN), Krakow (Poland)], E-mail: z5waligo@cyf-kr.edu.pl

    2008-02-15

    We have performed systematic measurements of the efficiency, C{sub E}=/, of MTS-N (LiF:Mg,Ti) and LiB (Li{sub 2}B{sub 4}O{sub 7}:Mn,Si) thermoluminescence (TL) detectors exposed to electron radiotherapy beams of nominal energy 6, 9, 12, 16 and 20 MeV relative to Co-60 or 6 MV photon beams ( is the average TL output of a batch of detectors exposed to a given dose of photon beam radiation or to a beam of electrons of energy E). The TL detectors were sintered pellets of 4.5 mm diameter and ca. 0.8 mm thickness. Detectors were exposed in water to 2 Gy at respective energy-dependent depths d{sub max} applied in clinical dosimetry. The obtained results were re-calculated versus mean electron energy in the beam at depths d{sub max}. We found that, for clinical purposes, both types of TL detectors show no energy dependence: presented as average values over the investigated energy range, for MTS-N detectors =1.07{+-}1.1% and for LiB =1.03{+-}1.7%. Thus, while no correction is required for dose values estimated by LiB TLDs, the under-response of MTS-N detectors exposed to a beam of electrons has to be corrected by about 7%. At mean energy of electrons in therapeutic electron beams below about 5 MeV a decline in the response of both types of TL detectors is observed.

  6. Revealing by secondary electronic emission of internal electric fields in the yttriated zirconia, irradiated by electrons of 1 MeV; Mise en evidence par emission electronique secondaire de champs electriques internes dans la zircone yttriee, irradiee par des electrons de 1 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Blaise, G. [CEA Saclay, Service de Physique et Chimie des Surfaces et Interfaces (DSM/IRAMIS/SPCSI), 91 - Gif-sur-Yvette (France); Paris-11 Univ., 91 - Orsay (France). Lab. de Physique des Solides

    2007-07-01

    The defects due to irradiation in a dielectric material present an activity which can generate macroscopic internal electric fields. A method of investigation of these fields, based on the measure of the Secondary Electronic Emission coefficient, has been developed on a scanning electric microscope. This ones contains two low noise detectors which respectively measure the influence current I{sub IC} produced by the charges trapping in the material and the current I{sub SB} due to secondary and backscattered electrons which come from the sample. The Secondary Emission coefficient is given by {sigma}=I{sub SB}/(I{sub SB}+I{sub IC}). The charges trapping during an electrons injection leads to a variation of {sigma} for its intrinsic value {sigma}{sub 0} relative to the uncharged material, until the stationary value {sigma}{sub st}=1 corresponding to the auto-regulated condition. This variation is due to the development of an internal electric field produced by the accumulation of the charges trapped during injection. In comparing the evolutions of {sigma} of a fresh yttriated zirconia and of an yttriated zirconia irradiated by electrons of 1 MeV with a dose rate of 10{sup 18} e/cm{sup 2}, it has been revealed that an internal field (due to irradiation) of about 0.5*10{sup 6} V/m exists at a depth of the micron order. This field, directed towards the outside of the material surface, is attributed to the F{sup +} defects and to the T centers produced by the impact of the electrons of 1 MeV. In carrying out annealings until 1000 K, a progressive disappearance of this field is observed in the temperature range of 400-600 K, directly due to the F{sup +} defects and T centers recovery, as it has been observed by ESR. An internal field three times weaker than the preceding ones has been revealed at a few nm under the surface. Its disappearance from a temperature of 1000 K suggests that it is due to the redistribution of the chemical species into the surface, during the

  7. Industrial application of electron sources with plasma emitters

    CERN Document Server

    Belyuk, S I; Rempe, N G

    2001-01-01

    Paper contains a description, operation, design and parameters of electron sources with plasma emitters. One presents examples of application of these sources as part of automated electron-beam welding lines. Paper describes application of such sources for electron-beam deposition of composite powders. Electron-beam deposition is used to rebuild worn out part and to increase strength of new parts of machines and tools. Paper presents some examples of rebuilding part and the advantages gained in this case

  8. Dosimetry applied in total skin irradiation using an electron beam with 4 MeV nominal energy; Dosimetria aplicada na irradiacao de toda a pele utilizando feixes de eletrons com energia nominal de 4 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Poli, Maria Esmeralda Ramos

    2000-07-01

    This work describes a dosimetric process to a treatment technique used on diseases that affect all body's skin surface, as mycosis fungoides, using total skin irradiation with electron beam with 4 MeV nominal energy. The goals are to improve the uniformity of the dose in the patient, as well to reduce the problems with the overlapping treatment fields, that occurs in conventional treatment that uses 1 meter of focus-skin distance and to reduce the treatment time to the patient. The patient is placed on a rotative base stand up and perpendicular to the beam, distant 2.83 meters from the gantry and he assumes successively 6 positions with 60 degrees of interval between the rotations. In each position the patient receives a couple of beams (angulated at 19.5 degrees above and below the transversal axis in the middle line of the patient). The dosimetric data obtained were compared with the international protocols as AAPM Rep. 23 (AAPM, 1988). The delivered doses in the patient were measured with dosimetric films placed in an anthropomorphic phantom and with thermoluminescent dosimeters placed on patient skin surface. The dose distributions in the phantom show an uniform dose variation in all thickness of interest so, it is possible to utilize this technique in the treatment of the mycosis fungoides. (author)

  9. Thermoluminescent response of LiF: Mg, Cu, P (GR-200) below an electron beam of 6 MeV; Respuesta termoluminiscente de LiF: Mg, Cu, P (GR-200) ante un haz de electrones de 6 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Torijano C, E.F.S.; Azorin N, J. [Universidad Autonoma Metropolitana-lztapalapa, Av. San Rafael Atlixco 87. Col. Vicentina, 09340 Mexico D.F. (Mexico); Villasenor N, I.; Lujan C, P.J. [Hospital General de Mexico, Balmis 148, 06726 Mexico D.F. (Mexico); Rivera M, T. [Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, Unidad Legaria del IPN, Av. Legaria 694, Col. Irrigacion, 11500 Mexico D.F. (Mexico)

    2007-07-01

    Full text: In this work the experimental results of studying the thermoluminescent response (TL) of LiF:Mg,Cu,P (GR-200) previously irradiated with 6 MeV electrons are presented. The electrons beam was generated by a Lineal Accelerator VARIAN I for medical use. The lineal accelerator is installed in the General Hospital of Mexico (HGM). A lot of 25 thermoluminescent dosemeters (DTL) was used. The mass and volume of each one of them were determined. Obtaining a variation of 14% in standard deviation (SD). The DTLs were irradiated to an energy of 6 MeV. The dose given to the DTL was of 50 c Gy. The linearity of the response of the GR-200 also was determined. (Author)

  10. Electron Linac design to drive bright Compton back-scattering gamma-ray sources

    Energy Technology Data Exchange (ETDEWEB)

    Bacci, A.; Rossi, A. R.; Serafini, L. [INFN-MI, Milano (Italy); Alesini, D.; Bellaveglia, M.; Boni, R.; Chiadroni, E.; Di Pirro, G.; Esposito, A.; Ferrario, M.; Gallo, A.; Gatti, G.; Ghigo, A.; Spataro, B.; Vaccarezza, C. [INFN-LNF, Frascati, Roma (Italy); Antici, P.; Migliorati, M.; Mostacci, A.; Palumbo, L. [University La Sapienza, Roma (Italy); Cianchi, A. [University of Tor Vergata, Roma (Italy); and others

    2013-05-21

    The technological development in the field of high brightness linear accelerators and high energy/high quality lasers enables today designing high brilliance Compton-X and Gamma-photon beams suitable for a wide range of applications in the innovative field of nuclear photonics. The challenging requirements of this kind of source comprise: tunable energy (1-20 MeV), very narrow bandwidth (0.3%), and high spectral density (10{sup 4} photons/s/eV). We present here a study focused on the design and the optimization of an electron Linac aimed to meet the source specifications of the European Extreme Light Infrastructure-Nuclear Physics project, currently funded and seeking for an innovative machine design in order to outperform state-of-the-art facilities. We show that the phase space density of the electron beam, at the collision point against the laser pulse, is the main quality factor characterizing the Linac.

  11. Clinical implementation of total skin electron irradiation treatment with a 6 MeV electron beam in high-dose total skin electron mode

    Energy Technology Data Exchange (ETDEWEB)

    Lucero, J. F., E-mail: fernando.lucero@hoperadiotherapy.com.gt [Universidad Nacional de Costa Rica, Heredia (Costa Rica); Hope International, Guatemala (Guatemala); Rojas, J. I., E-mail: isaac.rojas@siglo21.cr [Centro Médico Radioterapia Siglo XXI, San José (Costa Rica)

    2016-07-07

    Total skin electron irradiation (TSEI) is a special treatment technique offered by modern radiation oncology facilities, given for the treatment of mycosis fungoides, a rare skin disease, which is type of cutaneous T-cell lymphoma [1]. During treatment the patient’s entire skin is irradiated with a uniform dose. The aim of this work is to present implementation of total skin electron irradiation treatment using IAEA TRS-398 code of practice for absolute dosimetry and taking advantage of the use of radiochromic films.

  12. Effective atomic number and electron density of amino acids within the energy range of 0.122-1.330 MeV

    Science.gov (United States)

    More, Chaitali V.; Lokhande, Rajkumar M.; Pawar, Pravina P.

    2016-08-01

    Photon attenuation coefficient calculation methods have been widely used to accurately study the properties of amino acids such as n-acetyl-L-tryptophan, n-acetyl-L-tyrosine, D-tryptophan, n-acetyl-L-glutamic acid, D-phenylalanine, and D-threonine. In this study, mass attenuation coefficients (μm) of these amino acids for 0.122-, 0.356-, 0.511-, 0.662-, 0.884-, 1.170, 1.275-, 1.330-MeV photons are determined using the radio-nuclides Co57, Ba133, Cs137, Na22, Mn54, and Co60. NaI (Tl) scintillation detection system was used to detect gamma rays with a resolution of 8.2% at 0.662 MeV. The calculated attenuation coefficient values were then used to determine total atomic cross sections (σt), molar extinction coefficients (ε), electronic cross sections (σe), effective atomic numbers (Zeff), and effective electron densities (Neff) of the amino acids. Theoretical values were calculated based on the XCOM data. Theoretical and experimental values are found to be in a good agreement (error<5%). The variations of μm, σt, ε, σe, Zeff, and Neff with energy are shown graphically. The values of μm, σt, ε, σe are higher at lower energies, and they decrease sharply as energy increases; by contrast, Zeff and Neff were found to be almost constant.

  13. Generation of X-rays by 850 MeV electrons in a novel periodic multicrystal structure on a GaAs plate surface

    CERN Document Server

    Kaplin, V V; Zabaev, V N; Kanaev, V G; Litvin, S V; Timchenko, N A

    2000-01-01

    A novel type of a periodical crystalline target for the generation of coherent X-rays by relativistic electrons is described. The target has been done on the surface of a GaAs crystal plate by means of microlitography. The etched microstructure is a system of about 300 stripes 14 mu m thick, 100 mu m high and the gaps between the stripes are 29 mu m. The measured spectra and orientational dependences of the X-rays emitted at an angle of 19 deg. to the 850 MeV electron beam of the Tomsk synchrotron are discussed. The generated 63 keV radiation consists of parametric X-ray radiation (PXR) and diffracted X-ray transition radiation (DTR). It has been shown that the intensity of the DTR component of the generated X-rays is much more great than that of the PXR.

  14. Laser-driven electron beam generation for secondary photon sources with few terawatt laser pulses

    Science.gov (United States)

    Bohacek, K.; Chaulagain, U.; Horny, V.; Kozlova, M.; Krus, M.; Nejdl, J.

    2017-05-01

    Relativistic electron beams accelerated by laser wakefield have the ability to serve as sources of collimated, point-like and femtosecond X-ray radiation. Experimental conditions for generation of stable quasi-monoenergetic electron bunches using a femtosecond few-terawatt laser pulse (600 mJ, 50 fs) were investigated as they are crucial for generation of stable betatron radiation and X-ray pulses from inverse Compton scattering. A mixture of helium with argon, and helium with an admixture of synthetic air were tested for this purpose using different backing pressures and the obtained results are compared. The approach to use synthetic air was previously proven to stabilize the energy and energy spread of the generated electron beams at the given laser power. The accelerator was operated in nonlinear regime with forced self-injection and resulted in the generation of stable relativistic electron beams with an energy of tens of MeV and betatron X-ray radiation was generated in the keV range. A razor blade was tested to create a steep density gradient in order to improve the stability of electron injection and to increase the total electron bunch charge. It was proven that the stable electron and X-ray source can be built at small-scale facilities, which readily opens possibilities for various applications due to availability of such few-terawatt laser systems in many laboratories around the world.

  15. Evaluation of high-energy brachytherapy source electronic disequilibrium and dose from emitted electrons

    Energy Technology Data Exchange (ETDEWEB)

    Ballester, Facundo; Granero, Domingo; Perez-Calatayud, Jose; Melhus, Christopher S.; Rivard, Mark J. [Department of Atomic, Molecular and Nuclear Physics, University of Valencia, C/Dr. Moliner 50, E-46100 Burjassot (Spain) and IFIC, CSIC-University of Valencia, C/Dr. Moliner 50, E-46100 Burjassot (Spain); Department of Radiation Physics, ERESA, Hospital General Universitario, Avenida Tres Cruces, 2, E-46014 Valencia (Spain); Department of Radiation Oncology, La Fe University Hospital, Avenida Campanar 21, E-46009 Valencia (Spain); Department of Radiation Oncology, Tufts University School of Medicine, Boston, Massachusetts 02111 (United States)

    2009-09-15

    Purpose: The region of electronic disequilibrium near photon-emitting brachytherapy sources of high-energy radionuclides ({sup 60}Co, {sup 137}Cs, {sup 192}Ir, and {sup 169}Yb) and contributions to total dose from emitted electrons were studied using the GEANT4 and PENELOPE Monte Carlo codes. Methods: Hypothetical sources with active and capsule materials mimicking those of actual sources but with spherical shape were examined. Dose contributions due to source photons, x rays, and bremsstrahlung; source {beta}{sup -}, Auger electrons, and internal conversion electrons; and water collisional kerma were scored. To determine if conclusions obtained for electronic equilibrium conditions and electron dose contribution to total dose for the representative spherical sources could be applied to actual sources, the {sup 192}Ir mHDR-v2 source model (Nucletron B.V., Veenendaal, The Netherlands) was simulated for comparison to spherical source results and to published data. Results: Electronic equilibrium within 1% is reached for {sup 60}Co, {sup 137}Cs, {sup 192}Ir, and {sup 169}Yb at distances greater than 7, 3.5, 2, and 1 mm from the source center, respectively, in agreement with other published studies. At 1 mm from the source center, the electron contributions to total dose are 1.9% and 9.4% for {sup 60}Co and {sup 192}Ir, respectively. Electron emissions become important (i.e., >0.5%) within 3.3 mm of {sup 60}Co and 1.7 mm of {sup 192}Ir sources, yet are negligible over all distances for {sup 137}Cs and {sup 169}Yb. Electronic equilibrium conditions along the transversal source axis for the mHDR-v2 source are comparable to those of the spherical sources while electron dose to total dose contribution are quite different. Conclusions: Electronic equilibrium conditions obtained for spherical sources could be generalized to actual sources while electron contribution to total dose depends strongly on source dimensions, material composition, and electron spectra.

  16. AGILE as a particle detector: Magnetospheric measurements of 10-100 MeV electrons in L shells less than 1.2

    Science.gov (United States)

    Argan, A.; Piano, G.; Tavani, M.; Trois, A.

    2016-04-01

    We study the capability of the AGILE gamma ray space mission in detecting magnetospheric particles (mostly electrons) in the energy range 10-100 MeV. Our measurements focus on the inner magnetic shells with L ≲ 1.2 in the magnetic equator. The instrument characteristics and a quasi-equatorial orbit of ˜500 km altitude make it possible to address several important properties of the particle populations in the inner magnetosphere. We review the on board trigger logic and study the acceptance of the AGILE instrument for particle detection. We find that the AGILE effective geometric factor (acceptance) is R≃50 cm2 sr for particle energies in the range 10-100 MeV. Particle event reconstruction allows to determine the particle pitch angle with the local magnetic field with good accuracy. We obtain the pitch angle distributions for both the AGILE "pointing" phase (July 2007 to October 2009) and the "spinning" phase (November 2009 to present). In spinning mode, the whole range (0-180 degrees) is accessible every 7 min. We find a pitch angle distribution of the "dumbbell" type with a prominent depression near α = 90° which is typical of wave-particle resonant scattering and precipitation in the inner magnetosphere. Most importantly, we show that AGILE is not affected by solar particle precipitation events in the magnetosphere. The satellite trajectory intersects magnetic shells in a quite narrow range (1.0 ≲ L ≲ 1.2); AGILE then has a high exposure to a magnetospheric region potentially rich of interesting phenomena. The large particle acceptance in the 10-100 MeV range, the pitch angle determination capability, the L shell exposure, and the solar-free background make AGILE a unique instrument for measuring steady and transient particle events in the inner magnetosphere.

  17. The Earth's Electron Radiation Belts Modeling: from the Source Population to Relativistic Energies

    Science.gov (United States)

    Aseev, N.; Shprits, Y. Y.; Kellerman, A. C.; Drozdov, A.; Zhu, H.

    2016-12-01

    The dynamics of the Earth's electron radiation belts is characterized by intricate interactions of different particle populations. During the main phase of a geomagnetic storm, electron source (tens keV) and seed (hundreds keV) populations are injected from the plasma sheet to the outer belt region. The source population transfers energy to electromagnetic waves, while the seed population can be accelerated locally by interaction with chorus waves. Electrons can also be lost by scattering into the loss cone due to wave-particle interaction and by magnetopause shadowing due to outward radial motion. In this work, we present results of simulations of the dynamics of electron fluxes in the inner magnetosphere from a few keV to relativistic energies of several MeV using the VERB-4D code. The code includes radial, energy and pitch angle diffusion, convection and adiabatic effects due to compression or expansion of the magnetic field. We extended the spatial outer boundary of the computational domain to 10-15 RE which allow us to study, how the source and seed population particles are convected from the plasma sheet, accelerated to relativistic energies and lost to the atmosphere or the magnetopause. The results of simulations reproduce Van Allen Probes, GOES and THEMIS observations, indicating that magnetospheric convection is the main driver of electron dynamics above the GEO, while radial diffusion and local diffusion are the most important processes in the outer belt region.

  18. Vacuum nanoelectronic devices novel electron sources and applications

    CERN Document Server

    Evtukh, Anatoliy; Yilmazoglu, Oktay; Mimura, Hidenori; Pavlidis, Dimitris

    2015-01-01

    Introducing up-to-date coverage of research in electron field emission from nanostructures, Vacuum Nanoelectronic Devices outlines the physics of quantum nanostructures, basic principles of electron field emission, and vacuum nanoelectronic devices operation, and offers as insight state-of-the-art and future researches and developments.  This book also evaluates the results of research and development of novel quantum electron sources that will determine the future development of vacuum nanoelectronics. Further to this, the influence of quantum mechanical effects on high frequency vacuum nanoelectronic devices is also assessed. Key features: In-depth description and analysis of the fundamentals of Quantum Electron effects in novel electron sources. Comprehensive and up-to-date summary of the physics and technologies for THz sources for students of physical and engineering specialties and electronics engineers. Unique coverage of quantum physical results for electron-field emission and novel electron sourc...

  19. Experiments investigating the generation and transport of 10--12 MeV, 30-kA, mm-size electron beams with linear inductive voltage adders

    Energy Technology Data Exchange (ETDEWEB)

    Mazarakis, M.G.; Poukey, J.W.; Maenchen, J.E.

    1997-06-01

    The authors present the design, analysis, and results of the high-brightness electron beam experiments currently under investigation at Sandia National Laboratories. The anticipated beam parameters are the following: 8--12 MeV, 35--50 kA, 30--60 ns FWHM, and 0.5-mm rms beam radius. The accelerators utilized are SABRE and HERMES III. Both are linear inductive voltage adders modified to higher impedance and fitted with magnetically immersed foil less electron diodes. In the strong 20--50 Tesla solenoidal magnetic field of the diode, mm-size electron beams are generated and propagated to a beam stop. The electron beam is field emitted from mm-diameter needle-shaped cathode electrode and is contained in a similar size envelop by the strong magnetic field. These extremely space charge dominated beams provide the opportunity to study beam dynamics and possible instabilities in a unique parameter space. The SABRE experiments are already completed and have produced 30-kA, 1.5-mm FWHM electron beams, while the HERMES-III experiments are on-going.

  20. ELECTRON ENERGY PARTITION IN THE ABOVE-THE-LOOPTOP SOLAR HARD X-RAY SOURCES

    Energy Technology Data Exchange (ETDEWEB)

    Oka, Mitsuo; Krucker, Säm; Hudson, Hugh S.; Saint-Hilaire, Pascal, E-mail: moka@ssl.berkeley.edu [Space Sciences Laboratory, University of California, Berkeley, CA 94720 (United States)

    2015-02-01

    Solar flares produce non-thermal electrons with energies up to tens of MeVs. To understand the origin of energetic electrons, coronal hard X-ray (HXR) sources, in particular above-the-looptop sources, have been studied extensively. However, it still remains unclear how energies are partitioned between thermal and non-thermal electrons within the above-the-looptop source. Here we show that the kappa distribution, when compared to conventional spectral models, can better characterize the above-the-looptop HXRs (≳15 keV) observed in four different cases. The widely used conventional model (i.e., the combined thermal plus power-law distribution) can also fit the data, but it returns unreasonable parameter values due to a non-physical sharp lower-energy cutoff E{sub c}. In two cases, extreme-ultraviolet data were available from SDO/AIA and the kappa distribution was still consistent with the analysis of differential emission measure. Based on the kappa distribution model, we found that the 2012 July 19 flare showed the largest non-thermal fraction of electron energies about 50%, suggesting equipartition of energies. Considering the results of particle-in-cell simulations, as well as density estimates of the four cases studied, we propose a scenario in which electron acceleration is achieved primarily by collisionless magnetic reconnection, but the electron energy partition in the above-the-looptop source depends on the source density. In low-density above-the-looptop regions (few times 10{sup 9} cm{sup –3}), the enhanced non-thermal tail can remain and a prominent HXR source is created, whereas in higher-densities (>10{sup 10} cm{sup –3}), the non-thermal tail is suppressed or thermalized by Coulomb collisions.

  1. Modification of the microstructure and electronic properties of rutile TiO{sub 2} thin films with 79 MeV Br ion irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Rath, Haripriya [Department of Physics, U.N. (Auto.) College of Sc. and Tech, Adaspur, Cuttack 754011 (India); Department of Physics, Utkal University, Bhubaneswar 751004 (India); Dash, P. [Department of Physics, Utkal University, Bhubaneswar 751004 (India); Singh, U.P. [KIIT University, Bhubaneswar 751024 (India); Avasthi, D.K.; Kanjilal, D. [Inter-University Accelerator Center, New Delhi 110067 (India); Mishra, N.C., E-mail: nareshcmishra@gmail.com [Department of Physics, Utkal University, Bhubaneswar 751004 (India)

    2015-12-15

    Modifications induced by 79 MeV Br ions in rutile titanium dioxide thin films, synthesized by dc magnetron sputtering are presented. Irradiations did not induce any new XRD peak corresponding to any other phase. The area and the width of the XRD peaks were considerably affected by irradiation, and peaks shifted to lower angles. But the samples retained their crystallinity at the highest fluence (1 × 10{sup 13} ions cm{sup −2}) of irradiation even though the electronic energy loss of 79 MeV Br ions far exceeds the reported threshold value for amorphization of rutile TiO{sub 2}. Fitting of the fluence dependence of the XRD peak area to Poisson equation yielded the radius of ion tracks as 2.4 nm. Ion track radius obtained from the simulation based on the thermal spike model matches closely with that obtained from the fluence dependence of the area under XRD peaks. Williamson–Hall analysis of the XRD spectra indicated broadening and shifting of the peaks are a consequence of irradiation induced defect accumulation leading to microstrains, as was also indicated by Raman and UV–Visible absorption study.

  2. 基于GDT的14MeV中子源初步设计研究%Preliminary design of GDT-based 14 MeV neutron source

    Institute of Scientific and Technical Information of China (English)

    杜红飞; 陈德鸿; 蒋洁琼; 汪晖; 王福琼; 陈一平; 吴宜灿; FDS团队

    2012-01-01

    To meet the need of D-T fusion neutron source for fusion material testing, design goals were presented in this paper according to the international requirements of neutron source for fusion material testing. A preliminary design scheme of GDT-based 14 MeV neutron source was proposed, and a physics model of the neutron source was built based on progress of GDT experiments. Two preliminary design schemes (i. e. FDS-GDT1, FDS-GDT2) were designed; among which FDS-GDT2 can be used for fusion material testing with neutron first wall loading of 2 MW/m2.%为满足聚变材料测试对D-T聚变中子源的需要,本文首先根据国际上对用于聚变材料测试的中子源的要求给出设计目标,然后基于Gas Dynamic Trap(GDT)装置的实验进展,提出了基于GDT装置的14 MeV中子源的设计初步方案,并建立了GDT中子源的物理模型.计算分析给出了两套中子源参数初步方案,其中FDS-GDT2中子壁负载为2 MW/m2,可用于聚变材料的测试.

  3. Defects and phase change induced by giant electronic excitations with GeV ions and 30 MeV cluster beam

    Energy Technology Data Exchange (ETDEWEB)

    Thevenard, P.; Beranger, M. Canut, B.; Ramos, S.M.M.; Bonardi, N.; Fuchs, G. [Univ. Claude Bernard Lyon I, Villeurbanne (France). Dept. de Physique des Materiaux

    1997-11-01

    MgO and LiNbO{sub 3} single crystals were bombarded with GeV swift heavy ions (Pb, Gd) and 30 MeV C{sub 60} clusters to study the damage production induced by giant electronic processes at stopping power up to 100 keV/nm. The defect creation was characterized by optical absorption, transmission electron microscopy (TEM) and Rutherford backscattering spectrometry in channeling geometry (RBS-C). In MgO point defects (F type centers) and extended defects (dislocation loops) were created by ionization processes in addition to those associated with nuclear collisions. The F-center concentration induced by electronic energy excitations was studied at different temperatures and as a function of the particle electronic energy losses. TEM revealed that dislocation loops were produced close to the particle trajectories and amorphization was never observed. On the opposite, in LiNbO{sub 3} continuous amorphous tracks were evidenced above a threshold near 5 keV/nm. The dependence of this effects with various solid state parameters will be discussed.

  4. A Monte Carlo simulation code for calculating damage and particle transport in solids: The case for electron-bombarded solids for electron energies up to 900 MeV

    Science.gov (United States)

    Yan, Qiang; Shao, Lin

    2017-03-01

    Current popular Monte Carlo simulation codes for simulating electron bombardment in solids focus primarily on electron trajectories, instead of electron-induced displacements. Here we report a Monte Carol simulation code, DEEPER (damage creation and particle transport in matter), developed for calculating 3-D distributions of displacements produced by electrons of incident energies up to 900 MeV. Electron elastic scattering is calculated by using full-Mott cross sections for high accuracy, and primary-knock-on-atoms (PKAs)-induced damage cascades are modeled using ZBL potential. We compare and show large differences in 3-D distributions of displacements and electrons in electron-irradiated Fe. The distributions of total displacements are similar to that of PKAs at low electron energies. But they are substantially different for higher energy electrons due to the shifting of PKA energy spectra towards higher energies. The study is important to evaluate electron-induced radiation damage, for the applications using high flux electron beams to intentionally introduce defects and using an electron analysis beam for microstructural characterization of nuclear materials.

  5. 6-7 Mev Characteristic Gamma-Ray Source Using A Plasma Opening Switch And A Marx Bank

    Science.gov (United States)

    2011-06-01

    of Hawk, including the POS, is shown in Fig. 2a. The POS consists of 12 plasma guns made from coaxial cables that inject ionized plasma radially...inward between two coaxial conductors prior to firing the generator. The POS plasma conducts the generator current as a short circuit for about 700...vacuum gap in the plasma . High-energy electron- and ion-beams form in the plasma -filled coaxial region, with ions from the plasma and the polyethylene

  6. ISIS/EPI-Lo: A New Instrument for Measuring keV to MeV Ions and Electrons with Simultaneous Half-Sky Coverage on NASA's Solar Probe Plus Mission

    Science.gov (United States)

    Hill, M. E.; Mitchell, D. G.; McNutt, R. L., Jr.; Cooper, S.; Crew, A. B.; Dupont, A.; Hayes, J.; Hoffer, E.; Nelson, K.; Parker, C.; Schlemm, C., II; Seifert, H.; Stokes, M.; Angold, N. G.; McComas, D. J.; Weidner, S.; Wiedenbeck, M. E.

    2016-12-01

    The Solar Probe Plus (SPP) Mission's Integrated Science Investigation of the Sun (ISIS) is a suite of two energetic particle instruments, EPI-Lo and EPI-Hi, covering lower ( 10 keV-100 MeV) and higher ( 1-100 MeV/nuc) energies, respectively. The ISIS team will investigate the origins, acceleration, and transport of energetic particles in the corona and inner heliosphere during the planned 7-year, 24-orbit mission, with a perihelion initially of 0.16 AU (36 Solar radii; RS), the three final orbits reaching 0.044 AU (9.9 RS). EPI-Lo has a novel approach to obtaining large angular coverage, well-suited to 3-axis stabilized spacecraft such as SPP, by densely sampling its 2π steradian field of view with 80 apertures organized in eight matching, 10-aperture wedges. Each wedge relies primarily on time-of-flight (TOF) mass spectrometer techniques, employing thin secondary-electron-emitting foils, microchannel plates, and solid state detectors (SSDs), to measure ions from 50 keV - 15 MeV and electrons from 50-500 keV. Signal attenuation, absorbers, TOF-only measurements, and SSD-only techniques are used to extend this energy range higher and lower. In 2015 and 2016 we made measurements with engineering units and flight-spare EPI-Lo wedges at accelerators and with radioactive sources; in addition to presenting the instrument design, we will report the results from these tests to characterize the instrument's measurement performance.

  7. Matching from H(-) multicusp source to central region of a 100 MeV compact cyclotron for high current injection.

    Science.gov (United States)

    Yao, Hongjuan; Zhang, Tianjue; Lu, Yinlong; Jia, Xianlu; Guan, Fengping; Lin, Yuzheng

    2008-02-01

    The way of matching the beam from an external ion source to the central region of the cyclotron CYCIAE-100 is presented in this article. The transverse acceptances of the central region were calculated, which provided the matching ellipse parameter requirements to the injection transport optics design. The optics of the injection line was simulated using TRANSOPTR, which allowed space charge effect calculation, and neutralization was taken into account.

  8. Matching from H- multicusp source to central region of a 100MeV compact cyclotron for high current injectiona)

    Science.gov (United States)

    Yao, Hongjuan; Zhang, Tianjue; Lu, Yinlong; Jia, Xianlu; Guan, Fengping; Lin, Yuzheng

    2008-02-01

    The way of matching the beam from an external ion source to the central region of the cyclotron CYCIAE-100 is presented in this article. The transverse acceptances of the central region were calculated, which provided the matching ellipse parameter requirements to the injection transport optics design. The optics of the injection line was simulated using TRANSOPTR, which allowed space charge effect calculation, and neutralization was taken into account.

  9. The Orsay polarized electron source from a flowing helium afterglow

    Science.gov (United States)

    Arianer, J.; Brissaud, I.; Essabaa, S.; Humblot, H.; Zerhouni, W.

    1993-12-01

    A polarized electron source was designed at Orsay. We have chosen to adapt the flowing helium afterglow source working at Rice University because it provides a very high polarization. We have investigated a new way for the optical pumping of the helium metastables. An 85% electron polarization was reached.

  10. Ribbon electron beam formation by a forevacuum plasma electron source

    Energy Technology Data Exchange (ETDEWEB)

    Klimov, A. S., E-mail: klimov@main.tusur.ru; Burdovitsin, V. A. [Tomsk State University of Control System and Radioelectronics (Russian Federation); Grishkov, A. A. [SB RAS, Institute of High Current Electronics (Russian Federation); Oks, E. M.; Zenin, A. A.; Yushkov, Yu. G. [Tomsk State University of Control System and Radioelectronics (Russian Federation)

    2016-01-15

    Results of the numerical analysis and experimental research on ribbon electron beam generation based on hollow cathode discharge at forevacuum gas pressure are presented. Geometry of the accelerating gap has modified. It lets us focus the ribbon electron beam and to transport it on a distance of several tens of centimeters in the absence of an axial magnetic field. The results of numerical simulations are confirmed by the experiment.

  11. Investigation of solar cells fabricated on low-cost silicon sheet materials using 1 MeV electron irradiation

    Science.gov (United States)

    Kachare, A. H.; Hyland, S. L.; Garlick, G. F. J.

    1981-01-01

    The use of high energy electron irradiation is investigated as a controlled means to study in more detail the junction depletion layer processes of solar cells made on various low-cost silicon sheet materials. Results show that solar cells made on Czochralski grown silicon exhibit enhancement of spectral response in the shorter wavelength region when irradiated with high energy electrons. The base region damage can be reduced by subsequent annealing at 450 C which restores the degraded longer wavelength response, although the shorter wavelength enhancement persists. The second diode component of the cell dark forward bias current is also reduced by electron irradiation, while thermal annealing at 450 C without electron irradiation can also produce these same effects. Electron irradiation produces small changes in the shorter wavelength spectral responses and junction improvements in solar cells made on WEB, EFG, and HEM silicon. It is concluded that these beneficial effects on cell characteristics are due to the reduction of oxygen associated deep level recombination centers in the N(+) diffused layer and in the junction.

  12. Investigation of solar cells fabricated on low-cost silicon sheet materials using 1 MeV electron irradiation

    Science.gov (United States)

    Kachare, A. H.; Hyland, S. L.; Garlick, G. F. J.

    1981-01-01

    The use of high energy electron irradiation is investigated as a controlled means to study in more detail the junction depletion layer processes of solar cells made on various low-cost silicon sheet materials. Results show that solar cells made on Czochralski grown silicon exhibit enhancement of spectral response in the shorter wavelength region when irradiated with high energy electrons. The base region damage can be reduced by subsequent annealing at 450 C which restores the degraded longer wavelength response, although the shorter wavelength enhancement persists. The second diode component of the cell dark forward bias current is also reduced by electron irradiation, while thermal annealing at 450 C without electron irradiation can also produce these same effects. Electron irradiation produces small changes in the shorter wavelength spectral responses and junction improvements in solar cells made on WEB, EFG, and HEM silicon. It is concluded that these beneficial effects on cell characteristics are due to the reduction of oxygen associated deep level recombination centers in the N(+) diffused layer and in the junction.

  13. The evolution of electronic reference sources

    OpenAIRE

    Van Epps, Amy S

    2004-01-01

    Purpose To provide a historical look at the development of web versions of reference materials and discuss what makes an easy-to-use and useful electronic handbook. Design/methodology/approach Electronic reference materials were limited to handbooks available on the web. Observations and assumptions about usability are tested with an information retrieval test for specific tasks in print and online editions of the same texts. Findings Recommended adoption of those elements which create a w...

  14. The evolution of electronic reference sources

    OpenAIRE

    Van Epps, Amy S.

    2004-01-01

    Purpose To provide a historical look at the development of web versions of reference materials and discuss what makes an easy-to-use and useful electronic handbook. Design/methodology/approach Electronic reference materials were limited to handbooks available on the web. Observations and assumptions about usability are tested with an information retrieval test for specific tasks in print and online editions of the same texts. Findings Recommended adoption of those elements which create a w...

  15. Global MHD Test Particle Simulations of >10 MeV Radiation Belt Electrons During Sudden Storm Commencement

    Science.gov (United States)

    2007-09-22

    L-shell (L) from the Proton/Electron Telescope (PET) (K. Shiokawa , private communication, 2005), roughly half on the Solar Anomalous and...Slocum, J. E. Mazur, M. D. Looper, R. S. Selesnick, and Phys., 12, 417. K. Shiokawa (2005), Geoeffectiveness of shocks in populating the radia- Mazur

  16. Effect of 8 MeV electron beam irradiation on the structural and optical properties of CeO{sub 2} nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Babitha, K.K.; Priyanka, K.P. [Nanoscience Research Centre (NSRC), Department of Physics, Nirmala College, Muvattupuzha, 686 661, Kerala (India); Sreedevi, A. [Department of Applied Science and Humanities, Thejus Engineering College, Thrissur, 680584 Kerala (India); Ganesh, S. [Microtron Centre, Mangalore University, Mangalagangotri, 574 199 Karnataka (India); Varghese, Thomas, E-mail: nanoncm@gmail.com [Nanoscience Research Centre (NSRC), Department of Physics, Nirmala College, Muvattupuzha, 686 661, Kerala (India)

    2014-12-15

    The effect of 8 MeV electron beam irradiation on the structural and optical properties of cerium oxide nanoparticles was investigated. Ceria nanoparticles were synthesized by chemical precipitation method, and characterized by X-ray diffraction, transmission electron microscopy, ultraviolet–visible, photoluminescence and Raman spectroscopy. Ultraviolet–visible absorption spectra, photoluminescence and Raman spectra of beam irradiated samples were modified, and shifted to blue region, which were attributed to quantum size effect. Systematic observations found that nonstoichiometry, defects and size reduction caused by beam irradiation have great influence on optical band gap, blue shift, photoluminescence and Raman band modifications. Moreover, electron beam irradiation is a suitable technique to enhance the structural and optical properties of nanoceria by controlling the particle size, which may lead to potentially useful technological applications. - Highlights: • Investigated effect of beam irradiation on CeO{sub 2} nanoparticles • Beam irradiation caused size reduction and surface modification. • It increases microstrain, decreases d-spacing and broadens XRD peaks. • It also modifies optical band gap, absorption, PL and Raman bands.

  17. Emittance of a Field Emission Electron Source

    Science.gov (United States)

    2010-01-05

    approximately correct. The gate and switching time A thermionic source is run space-charge limited for which the current varies as a power 3 /2 of the grid...and millimeter-wave power amplifiers that use thermionic cathodes, requiring the sources to produce a current density characteristic of that in the...Rb radius, magnetic field strength B, accelerating voltage Vb, frequency f inversely related to Rb, harmonic number n, and emit- tance via 1− J

  18. Generation of stable and low-divergence 10-MeV quasimonoenergetic electron bunch using argon gas jet

    Directory of Open Access Journals (Sweden)

    M. Mori

    2009-08-01

    Full Text Available The pointing stability and divergence of a quasimonoenergetic electron bunch generated in a self-injected laser-plasma acceleration regime using 4 TW laser is studied. A pointing stability of 2.4 mrad root-mean-square (rms and a beam divergence of 10.6 mrad (rms were obtained using an argon gas-jet target for 50 sequential shots, while these values were degraded by a factor of 3 at the optimum condition using helium. The peak electron energies were 8.5±0.7 and 24.8±3.6  MeV using argon and helium, respectively. The experimental results indicate that the different propagation condition could be generated with the different material, although it is performed with the same irradiation condition.

  19. Accurate transport simulation of electron tracks in the energy range 1 keV-4 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Cobut, V. E-mail: vincent.cobut@chim.u-cergy.fr; Cirioni, L.; Patau, J.P

    2004-01-01

    Multipurpose electron transport simulation codes are widely used in the fields of radiation protection and dosimetry. Broadly based on multiple scattering theories and continuous energy loss stopping powers with some mechanism taking straggling into account, they give reliable answers to many problems. However they may be unsuitable in some specific situations. In fact, many of them are not able to accurately describe particle transport through very thin slabs and/or in high atomic number materials, or also when knowledge of high-resolution depth dose distributions is required. To circumvent these deficiencies, we developed a Monte Carlo code simulating each interaction along electron tracks. Gas phase elastic cross sections are corrected to take into account solid state effects. Inelastic interactions are described within the framework of the Martinez et al. [J. Appl. Phys. 67 (1990) 2955] theory intended to deal with energy deposition in both condensed insulators and conductors. The model described in this paper is validated for some materials as aluminium and silicon, encountered in spectrometric and dosimetric devices. Comparisons with experimental, theoretical and other simulation results are made for angular distributions and energy spectra of transmitted electrons through slabs of different thicknesses and for depth energy distributions in semi-infinite media. These comparisons are quite satisfactory.

  20. Single-Shot Electron Diffraction using a Cold Atom Electron Source

    CERN Document Server

    Speirs, Rory W; Nugent, Keith A; Sparkes, Benjamin M; Scholten, Robert E

    2015-01-01

    Cold atom electron sources are a promising alternative to traditional photocathode sources for use in ultrafast electron diffraction due to greatly reduced electron temperature at creation, and the potential for a corresponding increase in brightness. Here we demonstrate single-shot, nanosecond electron diffraction from monocrystalline gold using cold electron bunches generated in a cold atom electron source. The diffraction patterns have sufficient signal to allow registration of multiple single-shot images, generating an averaged image with significantly higher signal-to-noise ratio than obtained with unregistered averaging. Reflection high-energy electron diffraction (RHEED) was also demonstrated, showing that cold atom electron sources may be useful in resolving nanosecond dynamics of nanometre scale near-surface structures.

  1. Backward-propagating MeV electrons from $10^{18}$ W/cm$^2$ laser interactions with water

    CERN Document Server

    Morrison, J T; Frische, K D; Feister, S; Ovchinnikov, V M; Nees, J A; Orban, C; Freeman, R R; Roquemore, W M

    2015-01-01

    We present an experimental study of the generation of $\\sim$MeV electrons opposite to the direction of laser propagation following the relativistic interaction at normal incidence of a $\\sim$3 mJ, $10^{18}$ W/cm$^2$ short pulse laser with a flowing 30 $\\mu$m diameter water column target. Faraday cup measurements record hundreds of pC charge accelerated to energies exceeding 120 keV, and energy-resolved measurements of secondary x-ray emissions reveal an x-ray spectrum peaking above 800 keV, which is significantly higher energy than previous studies with similar experimental conditions and more than five times the $\\sim$110 keV ponderomotive energy scale for the laser. We show that the energetic x-rays generated in the experiment result from backward-going, high-energy electrons interacting with the focusing optic and vacuum chamber walls with only a small component of x-ray emission emerging from the target itself. We also demonstrate that the high energy radiation can be suppressed through the attenuation of...

  2. Optical and electronic properties of sub-surface conducting layers in diamond created by MeV B-implantation at elevated temperatures

    Science.gov (United States)

    Willems van Beveren, L. H.; Liu, R.; Bowers, H.; Ganesan, K.; Johnson, B. C.; McCallum, J. C.; Prawer, S.

    2016-06-01

    Boron implantation with in-situ dynamic annealing is used to produce highly conductive sub-surface layers in type IIa (100) diamond plates for the search of a superconducting phase transition. Here, we demonstrate that high-fluence MeV ion-implantation, at elevated temperatures avoids graphitization and can be used to achieve doping densities of 6 at. %. In order to quantify the diamond crystal damage associated with implantation Raman spectroscopy was performed, demonstrating high temperature annealing recovers the lattice. Additionally, low-temperature electronic transport measurements show evidence of charge carrier densities close to the metal-insulator-transition. After electronic characterization, secondary ion mass spectrometry was performed to map out the ion profile of the implanted plates. The analysis shows close agreement with the simulated ion-profile assuming scaling factors that take into account an average change in diamond density due to device fabrication. Finally, the data show that boron diffusion is negligible during the high temperature annealing process.

  3. Wind Power - A Power Source Enabled by Power Electronics

    DEFF Research Database (Denmark)

    Blaabjerg, Frede; Chen, Zhe

    2004-01-01

    . The deregulation of energy has lowered the investment in bigger power plants, which means the need for new electrical power sources may be very high in the near future. Two major technologies will play important roles to solve the future problems. One is to change the electrical power production sources from...... electronics is changing from being a minor energy source to be acting as an important power source. By that wind power is also getting an added value....

  4. Wind power - a power source now enabled by power electronics

    DEFF Research Database (Denmark)

    Blaabjerg, Frede; Iov, Florin

    2007-01-01

    energy at the end-user should be set up. Deregulation of energy has lowered the investment in larger power plants, which means the need for new electrical power sources may be increased in the near future. Two major technologies will play important roles to solve the future problems. One is to change...... renewable energy sources, wind energy, which by means of power electronics are changing from being minor energy sources to be acting as important power sources in the energy system....

  5. Investigation of planar channeling radiation on diamond and quartz crystals at electron energies between 14 and 34 MeV and probing the influence of ultrasonic waves on channeling radiation

    Energy Technology Data Exchange (ETDEWEB)

    Azadegan, B.

    2007-11-15

    Measurements of planar channeling radiation (CR) have been performed at the electron beam of ELBE within an energy range between 14 and 34 MeV and for thicknesses of the diamond crystals between 42.5 and 500 {mu}m. Absolute CR photon yields have for the first time been obtained for the above given ranges of electron energy and crystal thickness. The square-root dependence of the planar CR photon yield on the thickness of diamond crystals has been confirmed. A systematic quantitative investigation of the influence of the crystal thickness on the CR line shape has for the first time been performed. The mean-squared multiple-scattering angle effective for planar CR observed in forward direction has been found to be weaker as assumed from scattering in amorphous targets. Scaling laws deduced from the measured CR data are of advantage for the operation of a CR source. The second part of this thesis deals with the possibility of stimulation of CR emission by means of ultrasonic vibrations excited in a piezoelectric single crystal. Since the knowledge of the CR spectra generated on undisturbed quartz crystals is a necessary precondition for some investigation of the influence of US, planar CR has for the first time been measured at medium electron energies for a variety of planes in quartz. As a consequence of the hexagonal structure of this crystal, relative intense CR could be registered even out of planes with indices larger than one. On the base of the non-linear optics method, occupation functions and spectral distributions of planar CR have been calculated for channeling of 20 MeV electrons in the (01 anti 15) plane of a 20 {mu}m thick quartz crystal at resonant influence of ultrasound (US). The resonance frequencies have been deduced from the measurements of CR spectra performed on quartz. First experimental investigations of the influence of US on CR started at ELBE aimed at the study of the effect of non-resonant ultrasonic vibrations excited in a 500 {mu}m thick

  6. Injector for CESAR (2 MeV electron storage ring): 2-beam, 2 MV van de Graaff generator.

    CERN Document Server

    1963-01-01

    The van de Graaff generator in its tank. For voltage-holding, the tank was filled with pressurized extra-dry nitrogen. 2 beams emanated from 2 separate electron-guns. The left beam, for injection into the CESAR ring, was pulsed at 50 Hz, with currents of up to 1 A for 400 ns. The right beam was sent to a spectrometer line. Its pulselength was also 400 ns, but the pulse current was 12 microA, at a rate variable from 50 kHz to 1 MHz. This allowed stabilization of the top-terminal voltage to an unprecedented stability of +- 100 V, i.e. 6E-5. Although built for a nominal voltage of 2 MV, the operational voltage was limited to 1.75 MV in order to minimize voltage break-down events.

  7. Shutterless ion mobility spectrometer with fast pulsed electron source

    Science.gov (United States)

    Bunert, E.; Heptner, A.; Reinecke, T.; Kirk, A. T.; Zimmermann, S.

    2017-02-01

    Ion mobility spectrometers (IMS) are devices for fast and very sensitive trace gas analysis. The measuring principle is based on an initial ionization process of the target analyte. Most IMS employ radioactive electron sources, such as 63Ni or 3H. These radioactive materials have the disadvantage of legal restrictions and the electron emission has a predetermined intensity and cannot be controlled or disabled. In this work, we replaced the 3H source of our IMS with 100 mm drift tube length with our nonradioactive electron source, which generates comparable spectra to the 3H source. An advantage of our emission current controlled nonradioactive electron source is that it can operate in a fast pulsed mode with high electron intensities. By optimizing the geometric parameters and developing fast control electronics, we can achieve very short electron emission pulses for ionization with high intensities and an adjustable pulse width of down to a few nanoseconds. This results in small ion packets at simultaneously high ion densities, which are subsequently separated in the drift tube. Normally, the required small ion packet is generated by a complex ion shutter mechanism. By omitting the additional reaction chamber, the ion packet can be generated directly at the beginning of the drift tube by our pulsed nonradioactive electron source with only slight reduction in resolving power. Thus, the complex and costly shutter mechanism and its electronics can also be omitted, which leads to a simple low-cost IMS-system with a pulsed nonradioactive electron source and a resolving power of 90.

  8. Holographic free-electron light source

    Science.gov (United States)

    Li, Guanhai; Clarke, Brendan P.; So, Jin-Kyu; MacDonald, Kevin F.; Zheludev, Nikolay I.

    2016-12-01

    Recent advances in the physics and technology of light generation via free-electron proximity and impact interactions with nanostructures (gratings, photonic crystals, nano-undulators, metamaterials and antenna arrays) have enabled the development of nanoscale-resolution techniques for such applications as mapping plasmons, studying nanoparticle structural transformations and characterizing luminescent materials (including time-resolved measurements). Here, we introduce a universal approach allowing generation of light with prescribed wavelength, direction, divergence and topological charge via point-excitation of holographic plasmonic metasurfaces. It is illustrated using medium-energy free-electron injection to generate highly-directional visible to near-infrared light beams, at selected wavelengths in prescribed azimuthal and polar directions, with brightness two orders of magnitude higher than that from an unstructured surface, and vortex beams with topological charge up to ten. Such emitters, with micron-scale dimensions and the freedom to fully control radiation parameters, offer novel applications in nano-spectroscopy, nano-chemistry and sensing.

  9. Injector for CESAR (2 MeV electron storage ring): 2-beam, 2 MV van de Graaff generator; tank removed.

    CERN Multimedia

    1968-01-01

    The van de Graaff generator in its tank. For voltage-holding, the tank was filled with pressurized extra-dry nitrogen. 2 beams emanated from 2 separate electron-guns. The left beam, for injection into the CESAR ring, was pulsed at 50 Hz, with currents of up to 1 A for 400 ns. The right beam was sent to a spectrometer line. Its pulselength was also 400 ns, but the pulse current was 12 microA, at a rate variable from 50 kHz to 1 MHz. This allowed stabilization of the top-terminal voltage to an unprecedented stability of +- 100 V, i.e. 6E-5. Although built for a nominal voltage of 2 MV, the operational voltage was limited to 1.75 MV in order to minimize voltage break-down events. CESAR was terminated at the end of 1967 and dismantled in 1968. R.Nettleton (left) and H.Burridge (right) are preparing the van de Graaff for shipment to the University of Swansea.

  10. High-accuracy 233U(n, f ) cross-section measurement at the white-neutron source n TOF from near-thermal to 1 MeV neutron energy

    OpenAIRE

    Sarchiapone, L.; Savvidis, I.; Konovalov, V; Stephan, C.; Tagliente, G.; Krticka, M; Rudolf, G.; Kossionides, E.; Rullhusen, P; Leeb, H.; Salgado, J.; Capote, R.; Cano-Ott, D.; Mengoni, A.; Calviño Tavares, Francisco

    2009-01-01

    The 233U(n,f ) cross section has been measured at the white neutron source n TOF in a wide energy range with a dedicated fission ionization chamber. We report here the results from ∼30 meV to 1 MeV neutron energy. The 233U(n,f ) cross section has been determined relative to a reference sample of 235U(n,f )measured simultaneously with the same detector. The very high instantaneous neutron flux and the intrinsically low background of the n TOF installation result in an accuracy arou...

  11. Optical Pumping of Metastable Helium Atoms in Polarized Electron Sources

    Science.gov (United States)

    Brissaud, I.

    1995-04-01

    In this paper we present a comparison between the Orsay and Rice University polarized electron sources. Different explanations of the polarization degradation are discussed for the two cases. For the Rice source radiation, trapping can account for the observed reduction in polarization because of the high absorption cross sections associated with the D1 transition. Some improvements are proposed that might increase the electron polarization.

  12. Optical Pumping of Metastable Helium Atoms in Polarized Electron Sources

    OpenAIRE

    1995-01-01

    In this paper we present a comparison between the Orsay and Rice University polarized electron sources. Different explanations of the polarization degradation are discussed for the two cases. For the Rice source radiation, trapping can account for the observed reduction in polarization because of the high absorption cross sections associated with the D1 transition. Some improvements are proposed that might increase the electron polarization.

  13. Simulating radial diffusion of energetic (MeV electrons through a model of fluctuating electric and magnetic fields

    Directory of Open Access Journals (Sweden)

    T. Sarris

    2006-10-01

    Full Text Available In the present work, a test particle simulation is performed in a model of analytic Ultra Low Frequency, ULF, perturbations in the electric and magnetic fields of the Earth's magnetosphere. The goal of this work is to examine if the radial transport of energetic particles in quiet-time ULF magnetospheric perturbations of various azimuthal mode numbers can be described as a diffusive process and be approximated by theoretically derived radial diffusion coefficients. In the model realistic compressional electromagnetic field perturbations are constructed by a superposition of a large number of propagating electric and consistent magnetic pulses. The diffusion rates of the electrons under the effect of the fluctuating fields are calculated numerically through the test-particle simulation as a function of the radial coordinate L in a dipolar magnetosphere; these calculations are then compared to the symmetric, electromagnetic radial diffusion coefficients for compressional, poloidal perturbations in the Earth's magnetosphere. In the model the amplitude of the perturbation fields can be adjusted to represent realistic states of magnetospheric activity. Similarly, the azimuthal modulation of the fields can be adjusted to represent different azimuthal modes of fluctuations and the contribution to radial diffusion from each mode can be quantified. Two simulations of quiet-time magnetospheric variability are performed: in the first simulation, diffusion due to poloidal perturbations of mode number m=1 is calculated; in the second, the diffusion rates from multiple-mode (m=0 to m=8 perturbations are calculated. The numerical calculations of the diffusion coefficients derived from the particle orbits are found to agree with the corresponding theoretical estimates of the diffusion coefficient within a factor of two.

  14. Optimization of compton source performance through electron beam shaping

    Science.gov (United States)

    Malyzhenkov, Alexander; Yampolsky, Nikolai

    2017-03-01

    We investigate a novel scheme for significantly increasing the brightness of x-ray light sources based on inverse Compton scattering (ICS) - scattering laser pulses off relativistic electron beams. The brightness of ICS sources is limited by the electron beam quality, since electrons traveling at different angles, and/or having different energies, produce photons with different energies. Therefore, the spectral brightness of the source is defined by the 6D electron phase space shape and size, as well as laser beam parameters. The peak brightness of the ICS source can be maximized, then, if the electron phase space is transformed in a way such that all electrons scatter off the x-ray photons of same frequency in the same direction, arriving to the observer at the same time. We describe the x-ray photon beam quality through the Wigner function (6D photon phase space distribution), and derive it for the ICS source when the electron and laser rms matrices are arbitrary.

  15. Optimization of Compton Source Performance through Electron Beam Shaping

    Energy Technology Data Exchange (ETDEWEB)

    Malyzhenkov, Alexander [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Yampolsky, Nikolai [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-09-26

    We investigate a novel scheme for significantly increasing the brightness of x-ray light sources based on inverse Compton scattering (ICS) - scattering laser pulses off relativistic electron beams. The brightness of ICS sources is limited by the electron beam quality since electrons traveling at different angles, and/or having different energies, produce photons with different energies. Therefore, the spectral brightness of the source is defined by the 6d electron phase space shape and size, as well as laser beam parameters. The peak brightness of the ICS source can be maximized then if the electron phase space is transformed in a way so that all electrons scatter off the x-ray photons of same frequency in the same direction, arriving to the observer at the same time. We describe the x-ray photon beam quality through the Wigner function (6d photon phase space distribution) and derive it for the ICS source when the electron and laser rms matrices are arbitrary.

  16. Simulation of a two step TGF ignition above cloudtops with MeV electron input fluxes generated in the electric fields of lightning streamers

    Science.gov (United States)

    Connell, P. H.

    2014-12-01

    The origin of high energy electrons which contribute to the Runaway Electron Avalanche of a TGF are not precisely known, or yet observed, though the most obvious source would seem to be the products of cosmic ray showers, or electron avalanches generated in the high electric field near the tips of lightning leaders. With our TGF simulation software package LEPTRACK we can easily create all kinds of electric field geometries and are investigating the second scenario with combinations of lightning leader and streamer micro-fields producing electron avalanches, which may or may not be runaway, which are then input to the macro-fields expected at or above thunderstorm cloudtops.We will present the detailed evolution of photon, electron, neutron/proton and ionization density fields resulting to demonstrate the possibility that TGF origin is not one of the two models currently proposed but may be a combination of both.

  17. Polarized [sup 3]He ion source based on polarized electron capture

    Energy Technology Data Exchange (ETDEWEB)

    Ohshima, Takashi (Osaka Univ., Toyonaka (Japan). Faculty of Science)

    1993-11-01

    The [sup 3]He[sup +] ions which are formed by [sup 3]He[sup 2+] ions capturing the polarized electrons of the sodium atoms polarized by optical pumping become nuclear polarized beam, as electron polarization shifts to nuclei by ultrafine interaction. When the current of [sup 3]He[sup 2+] ions was 2 e[mu]A, and the degree of polarization of sodium atoms was 0.30[+-]0.05, the [sup 3]He[sup +] beam of nuclear polarization degree 0.0415[+-]0.0061 and beam current 40 nA was obtained. By carrying out the improvement such as the increase of the degree of polarization of sodium or the current of [sup 3]He[sup 2+], it can be expected to form the polarized beam of current more than 10 [mu]A and degree of polarization close to 30%. The polarization experiment carried out so far was mostly on protons and deuterons, and as for [sup 3]He, there was only one polarization experiment. In Research Center for Nuclear Physics, Osaka University, the [sup 3]He beam up to 530 MeV can be obtained by using the ring cyclotron, therefore, it was decided to develop the polarized [sup 3]He ion source using polarized electron capture. The principle of polarization formation, the experimental equipment consisting of ECR ion source, polarized Na target and [sup 3]He nuclear polarization measuring part, and the experimental results are reported. (K.I.).

  18. Solar electron source and thermionic solar cell

    Directory of Open Access Journals (Sweden)

    Parham Yaghoobi

    2012-12-01

    Full Text Available Common solar technologies are either photovoltaic/thermophotovoltaic, or use indirect methods of electricity generation such as boiling water for a steam turbine. Thermionic energy conversion based on the emission of electrons from a hot cathode into vacuum and their collection by an anode is also a promising route. However, thermionic solar conversion is extremely challenging as the sunlight intensity is too low for heating a conventional cathode to thermionic emission temperatures in a practical manner. Therefore, compared to other technologies, little has been done in this area, and the devices have been mainly limited to large experimental apparatus investigated for space power applications. Based on a recently observed “Heat Trap” effect in carbon nanotube arrays, allowing their efficient heating with low-power light, we report the first compact thermionic solar cell. Even using a simple off-the-shelf focusing lens, the device delivered over 1 V across a load. The device also shows intrinsic storage capacity.

  19. Secondary electron emission of thin carbon foils under the impact of hydrogen atoms, ions and molecular ions, under energies within the MeV range; Multiplicite des electrons secondaires emis par des cibles minces de carbone sous l'impact de projectiles H0, H2+, H3+ d'energie de l'ordre du MeV

    Energy Technology Data Exchange (ETDEWEB)

    Vidovic, Z

    1997-06-15

    This work focuses on the study of the emission statistics of secondary electrons from thin carbon foils bombarded with H{sup 0}, H{sub 2}{sup +} and H{sub 3}{sup +} projectiles in the 0.25-2.2 MeV energy range. The phenomenon of secondary electron emission from solids under the impact of swift ions is mainly due to inelastic interactions with target electrons. The phenomenological and theoretical descriptions, as well as a summary of the main theoretical models are the subject of the first chapter. The experimental set-up used to measure event by event the electron emission of the two faces of a thin carbon foil traversed by an energetic projectile is described in the chapter two. In this chapter are also presented the method and algorithms used to process experimental spectra in order to obtain the statistical distribution of the emitted electrons. Chapter three presents the measurements of secondary electron emission induced by H atoms passing through thin carbon foils. The secondary electron yields are studied in correlation with the emergent projectile charge state. We show the peculiar role of the projectile electron, whether it remains or not bound to the incident proton. The fourth chapter is dedicated to the secondary electron emission induced by H{sub 2}{sup +} and H{sub 3}{sup +} polyatomic ions. The results are interpreted in terms of collective effects in the interactions of these ions with solids. The role of the proximity of the protons, molecular ion fragments, upon the amplitude of these collective effects is evidenced from the study of the statistics of forward emission. These experiences allowed us to shed light on various aspects of atom and polyatomic ion inter-actions with solid surfaces. (author)

  20. Wind power - a power source now enabled by power electronics

    DEFF Research Database (Denmark)

    Blaabjerg, Frede; Iov, Florin

    2007-01-01

    energy at the end-user should be set up. Deregulation of energy has lowered the investment in larger power plants, which means the need for new electrical power sources may be increased in the near future. Two major technologies will play important roles to solve the future problems. One is to change...... the electrical power production sources from the conventional, fossil (and short term) based energy sources to renewable energy resources. Another is to use high efficient power electronics in power generation, power transmission/distribution and end-user application. This paper discuss the most emerging...... renewable energy sources, wind energy, which by means of power electronics are changing from being minor energy sources to be acting as important power sources in the energy system....

  1. Effect of high energy electron beam (10MeV) on specific heat capacity of low-density polyethylene/hydroxyapatite nano-composite.

    Science.gov (United States)

    Soltani, Z; Ziaie, F; Ghaffari, M; Beigzadeh, A M

    2017-02-01

    In the present work, thermal properties of low density polyethylene (LDPE) and its nano composites are investigated. For this purpose LDPE reinforced with different weight percents of hydroxyapatite (HAP) powder which was synthesized via hydrolysis method are produced. The samples were irradiated with 10MeV electron beam at doses of 75 to 250kGy. Specific heat capacity measurement have been carried out at different temperatures, i.e. 25, 50, 75 and 100°C using modulated temperature differential scanning calorimetry (MTDSC) apparatus and the effect of three parameters include of temperature, irradiation dose and the amount of HAP nano particles as additives on the specific heat capacity of PE/HAP have been investigated precisely. The MTDSC results indicate that the specific heat capacity have decreased by addition of nano sized HAP as reinforcement for LDPE. On the other hand, the effect of radiation dose is reduction in the specific heat capacity in all materials including LDPE and its nano composites. The HAP nano particles along with cross-link junctions due to radiation restrain the movement of the polymer chains in the vicinity of each particle and improve the immobility of polymer chains and consequently lead to reduction in specific heat capacity. Also, the obtained results confirm that the radiation effect on the specific heat capacity is more efficient than the reinforcing effect of nano-sized hydroxyapatite.

  2. A compact sup 3 H(p,gamma) sup 4 He 19.8 MeV gamma-ray source for energy calibration at the Sudbury Neutrino Observatory

    CERN Document Server

    Poon, A W P; Waltham, C E; Browne, M C; Robertson, R G H; Kherani, N P; Mak, H B

    2000-01-01

    The Sudbury Neutrino Observatory (SNO) is a new 1000-t D sub 2 O Cherenkov solar neutrino detector. A high-energy gamma-ray source is needed to calibrate SNO beyond the sup 8 B solar neutrino endpoint of 15 MeV. This paper describes the design and construction of a source that generates 19.8 MeV gamma rays using the sup 3 H(p,gamma) sup 4 He reaction (''pT''), and demonstrates that the source meets all the physical, operational and lifetime requirements for calibrating SNO. An ion source was built into this unit to generate and to accelerate protons up to 30 keV, and a high-purity scandium tritide target with a scandium-tritium atomic ratio of 1 : 2.0+-0.2 was included. This pT source is the first self-contained, compact, and portable high-energy gamma-ray source (E subgamma>10 MeV). (authors)

  3. Field structure and electron life times in the MEFISTO electron cyclotron resonance ion source

    Energy Technology Data Exchange (ETDEWEB)

    Bodendorfer, M. [EPFL - Ecole Polytechnique Federale de Lausanne (Switzerland); University of Berne, Institute of Physics, Space Research and Planetary Sciences, Siedlerstrasse 5, 3012 Berne (Switzerland)], E-mail: michael.bodendorfer@space.unibe.ch; Altwegg, K. [University of Berne, Institute of Physics, Space Research and Planetary Sciences, Siedlerstrasse 5, 3012 Berne (Switzerland); Shea, H. [EPFL - Ecole Polytechnique Federale de Lausanne (Switzerland); Wurz, P. [University of Berne, Institute of Physics, Space Research and Planetary Sciences, Siedlerstrasse 5, 3012 Berne (Switzerland)

    2008-03-15

    The complex magnetic field of the permanent magnet electron cyclotron resonance (ECR) ion source MEFISTO located at the University of Berne has been numerically simulated. For the first time the magnetized volume qualified for electron cyclotron resonance at 2.45 GHz and 87.5 mT has been analyzed in highly detailed 3D simulations with unprecedented resolution. New results were obtained from the numerical simulation of 25,211 electron trajectories. The evident characteristic ion sputtering trident of hexapole confined ECR ion sources has been identified with the field and electron trajectory distribution. Furthermore, unexpected long electron trajectory lifetimes were found.

  4. Field structure and electron life times in the MEFISTO electron cyclotron resonance ion source

    Science.gov (United States)

    Bodendorfer, M.; Altwegg, K.; Shea, H.; Wurz, P.

    2008-03-01

    The complex magnetic field of the permanent magnet electron cyclotron resonance (ECR) ion source MEFISTO located at the University of Berne has been numerically simulated. For the first time the magnetized volume qualified for electron cyclotron resonance at 2.45 GHz and 87.5 mT has been analyzed in highly detailed 3D simulations with unprecedented resolution. New results were obtained from the numerical simulation of 25,211 electron trajectories. The evident characteristic ion sputtering trident of hexapole confined ECR ion sources has been identified with the field and electron trajectory distribution. Furthermore, unexpected long electron trajectory lifetimes were found.

  5. Field structure and electron life times in the MEFISTO Electron Cyclotron Resonance Ion Source

    CERN Document Server

    Bodendorfer, Michael; Shea, Herbert; Wurz, Peter

    2008-01-01

    The complex magnetic field of the permanent-magnet electron cyclotron resonance (ECR) ion source MEFISTO located at the University of Bern have been numerically simulated. For the first time the magnetized volume qualified for electron cyclotron resonance at 2.45 GHz and 87.5 mT has been analyzed in highly detailed 3D simulations with unprecedented resolution. New results were obtained from the numerical simulation of 25211 electron trajectories. The evident characteristic ion sputtering trident of hexapole confined ECR sources has been identified with the field and electron trajectory distribution. Furthermore, unexpected long electron trajectory lifetimes were found.

  6. Miniature, low-power X-ray tube using a microchannel electron generator electron source

    Science.gov (United States)

    Elam, Wm. Timothy (Inventor); Kelliher, Warren C. (Inventor); Hershyn, William (Inventor); DeLong, David P. (Inventor)

    2011-01-01

    Embodiments of the invention provide a novel, low-power X-ray tube and X-ray generating system. Embodiments of the invention use a multichannel electron generator as the electron source, thereby increasing reliability and decreasing power consumption of the X-ray tube. Unlike tubes using a conventional filament that must be heated by a current power source, embodiments of the invention require only a voltage power source, use very little current, and have no cooling requirements. The microchannel electron generator comprises one or more microchannel plates (MCPs), Each MCP comprises a honeycomb assembly of a plurality of annular components, which may be stacked to increase electron intensity. The multichannel electron generator used enables directional control of electron flow. In addition, the multichannel electron generator used is more robust than conventional filaments, making the resulting X-ray tube very shock and vibration resistant.

  7. Multifunctional bulk plasma source based on discharge with electron injection

    Energy Technology Data Exchange (ETDEWEB)

    Klimov, A. S.; Medovnik, A. V. [Tomsk State University of Control Systems and Radioelectronics, Tomsk 634050 (Russian Federation); Tyunkov, A. V. [Tomsk State University of Control Systems and Radioelectronics, Tomsk 634050 (Russian Federation); Institute of High Current Electronics, Tomsk 634055 (Russian Federation); Savkin, K. P.; Shandrikov, M. V.; Vizir, A. V. [Institute of High Current Electronics, Tomsk 634055 (Russian Federation)

    2013-01-15

    A bulk plasma source, based on a high-current dc glow discharge with electron injection, is described. Electron injection and some special design features of the plasma arc emitter provide a plasma source with very long periods between maintenance down-times and a long overall lifetime. The source uses a sectioned sputter-electrode array with six individual sputter targets, each of which can be independently biased. This discharge assembly configuration provides multifunctional operation, including plasma generation from different gases (argon, nitrogen, oxygen, acetylene) and deposition of composite metal nitride and oxide coatings.

  8. Multicomponent Consideration of Electron Fraction of ECR Source Plasma

    CERN Document Server

    Shirkov, G D

    1999-01-01

    The development of physical model and mathematical simulation methods of electron and ion accumulation and production in the ECR ion source is presented. New equations represent electrons in the ECR plasma as a multicomponent media. In the result any kind of experimental or analytical electron distribution function can be approximated with a series of Maxwellian distributions with different temperatures and partial weights. Main positive plasma potential is introduced into consideration in addition to the negative potential dip for highly charged ion confinement. This potential regulates the loss rate of primary cold electrons from the plasma volume and completes the total picture of ECR plasma behavior. The first test of new model and code with recent experimental data of RIKEN 18 GHz ECR source has shown some new opportunities for investigators to study the ECR ion sources.

  9. High energy electron generation by the 15 mJ ultrashort pulse laser

    Energy Technology Data Exchange (ETDEWEB)

    Takano, K; Hotta, E; Nemoto, K [Department of Energy Sciences Tokyo Institute of Technology 4259 Nagatsuta-cho Midori-ku Yokohama 226-8502 (Japan); Nayuki, T; Oishi, Y; Fujii, T; Zhidkov, A [Central Research Institute of Electric Power Industry 2-6-1 Nagasaka, Yokosuka, Kanagawa, 240-0196 (Japan); Todoriki, M; Hasegawa, S [University of Tokyo 7-3-1 Hongo Bunkyo-ku Tokyo 113-8654 (Japan)], E-mail: k-tn@plasma.es.titech.ac.jp

    2008-05-01

    We propose a small size high energy X-ray source utilizing ultrashort pulse lasers, and a new scheme for generating quasi-monoenergetic electrons. In this paper, we developed a compact laser electron generator and performed experiment that generated energetic electrons over 1 MeV electrons with only 15 mJ laser energy. The temperatures of emitted electrons were measured to be 0.2 MeV and 0.25 MeV without and with prepulse, respectively.

  10. Spectral analysis of the effects of 1.7 MeV electron irradiation on the current transfer characteristic of cadmium telluride solar cells.

    Science.gov (United States)

    Tian, Jin-Xiu; Zeng, Guang-Gen; He, Xu-Lin; Zhang, Jing-Quan; Wu, Li-Li; Li, Wei; Li, Bing; Wang, Wen-Wu; Feng, Liang-Huan

    2014-04-01

    The effects of device performance of 1.7 MeV electron irradiation on cadmium telluride polycrystalline thin film solar cells with the structure of anti-radiation glass/ITO/ZnO/CdS/CdTe/ZnTe/ZnTe : Cu/Ni have been studied. Light and dark I-V characteristics, dark C-V characteristics, quantum efficiency (QE), admittance spectrum (AS) and other testing methods were used to analyze cells performance such as the open-circuit voltage (Voc), short-circuit current (Isc), fill factor (FF) and conversion efficiency (eta). It was explored to find out the effects of irradiation on the current transfer characteristic of solar cells combined with the dark current density (Jo), diode ideal factor (A), quantum efficiency, carrier concentration and the depletion layer width. The decline in short-circuit current was very large and the efficiency of solar cells decreased obviously after irradiation. Reverse saturation current density increased, which indicates that p-n junction characteristics of solar cells were damaged, and diode ideal factor was almost the same, so current transport mechanism of solar cells has not changed. Quantum efficiency curves proved that the damage of solar cells' p-n junction influenced the collection of photo-generated carriers. Irradiation made carrier concentration reduce to 40.6%. The analyses have shown that. A new defect was induced by electron irradiation, whose position is close to 0.58 eV above the valence band in the forbidden band, and capture cross section is 1.78 x 10(-16) cm2. These results indicate that irradiation influences the generation of photo-generated carriers, increases the risk of the carrier recombination and the reverse dark current, and eventually makes the short-circuit current of solar cells decay.

  11. MeV Pulsars: Modeling Spectra and Polarization

    Science.gov (United States)

    Kust Harding, Alice; Kalapotharakos, Constantinos

    2017-08-01

    A sub-population of energetic rotation-powered pulsars show high fluxes of pulsed non-thermal hard X-ray emission. While this ‘MeV pulsar’ population includes some radio-loud pulsars like the Crab and PSR B1509-58, a significant number have no detected radio or GeV emission, a mystery since gamma-ray emission is a common characteristic of pulsars with high spin-down power. Their steeply rising hard X-ray spectral energy distributions (SEDs) suggest peaks at 0.1 - 1 MeV but they have not been detected above 200 keV. Several upcoming and planned telescopes may shed light on the MeV pulsars. The Neutron star Interior Composition ExploreR (NICER) will observe pulsars in the 0.2 - 12 keV band and may discover additional MeV pulsars. The All-Sky Medium-Energy Gamma-Ray Observatory (AMEGO), in a study phase, can detect emission above 0.2 MeV and polarization in the 0.2 - 10 MeV band. We present a model for the spectrum and polarization of MeV pulsars where the X-ray emission comes from electron-positron pairs radiating in the outer magnetosphere and current sheet. This model predicts that the peak of the SED increases with surface magnetic field strength if the pairs are produced in polar cap cascades. For small inclination angles, viewing at large angles to the rotation axis can miss both the radio pulse and the GeV pulse from particles accelerating near the current sheet. Characterizing the emission and geometry of MeV pulsars can thus provide clues to the source of pairs and acceleration in the magnetosphere.

  12. Electron acceleration in a post-flare decimetric continuum source

    CERN Document Server

    Subramanian, P; Karlick'y, M; Sych, R; Sawant, H S; Ananthakrishnan, S; Subramanian, Prasad

    2007-01-01

    Aims: To calculate the power budget for electron acceleration and the efficiency of the plasma emission mechanism in a post-flare decimetric continuum source. Methods: We have imaged a high brightness temperature ($\\sim 10^{9}$K) post-flare source at 1060 MHz with the Giant Metrewave Radio Telescope (GMRT). We use information from these images and the dynamic spectrum from the Hiraiso spectrograph together with the theoretical method described in Subramanian & Becker (2006) to calculate the power input to the electron acceleration process. The method assumes that the electrons are accelerated via a second-order Fermi acceleration mechanism. Results: We find that the power input to the nonthermal electrons is in the range $3\\times 10^{25}$--$10^{26}$ erg/s. The efficiency of the overall plasma emission process starting from electron acceleration and culminating in the observed emission could range from $2.87\\times 10^{-9}$ to $2.38 \\times 10^{-8}$.

  13. An angular-selective electron source for the KATRIN experiment

    CERN Document Server

    Beck, M; Hein, H; Bauer, S; Baumeister, H; Bonn, J; Ortjohann, H -W; Ostrick, B; Rosendahl, S; Streubel, S; Valerius, K; Zboril, M; Weinheimer, C

    2014-01-01

    The KATRIN experiment is going to search for the average mass of the electron antineutrino with a sensitivity of 0.2 eV/c2. It uses a retardation spectrometer of MAC-E filter type to accurately measure the shape of the electron spectrum at the endpoint of tritium beta decay. In order to achieve the planned sensitivity the transmission properties of the spectrometer have to be understood with high precision for all initial conditions. For this purpose an electron source has been developed that emits single electrons at adjustable total energy and adjustable emission angle. The emission is pointlike and can be moved across the full flux tube that is imaged onto the detector. Here, we demonstrate that this novel type of electron source can be used to investigate the transmission properties of a MAC-E filter in detail.

  14. Pulsed electron source characterization with the modified three gradient method

    CERN Document Server

    Marghitu, S; Dinca, C; Marghitu, O

    2001-01-01

    Results from the Modified Three Gradient Method (MTGM), applied to a pulsed high intensity electron source, are presented. The MTGM makes possible the non-destructive determination of beam emittance in the space charge presence [1]. We apply the MTGM to an experimental system equipped with a Pierce convergent diode, working in pulse mode, and having a directly heated cathode as electron source. This choice was mainly motivated by the availability of an analytical characterization of this source type [2], as well as the extended use of the Pierce type sources in linear accelerators. The experimental data are processed with a numerical matching program, based on the K-V equation for an axially symmetric configuration [3], to determine the emittance and object cross-over position and diameter. The variation of these parameters is further investigated with respect to both electrical and constructive characteristics of the source: cathode heating current, extraction voltage, and cathode-anode distance.

  15. Characterization of electron temperature by simulating a multicusp ion source

    Science.gov (United States)

    Yeon, Yeong Heum; Ghergherehchi, Mitra; Kim, Sang Bum; Jun, Woo Jung; Lee, Jong Chul; Mohamed Gad, Khaled Mohamed; Namgoong, Ho; Chai, Jong Seo

    2016-12-01

    Multicusp ion sources are used in cyclotrons and linear accelerators to produce high beam currents. The structure of a multicusp ion source consists of permanent magnets, filaments, and an anode body. The configuration of the array of permanent magnets, discharge voltage of the plasma, extraction bias voltage, and structure of the multicusp ion source body decide the quality of the beam. The electrons are emitted from the filament by thermionic emission. The emission current can be calculated from thermal information pertaining to the filament, and from the applied voltage and current. The electron trajectories were calculated using CST Particle Studio to optimize the plasma. The array configuration of the permanent magnets decides the magnetic field inside the ion source. The extraction bias voltage and the structure of the multicusp ion source body decide the electric field. Optimization of the electromagnetic field was performed with these factors. CST Particle Studio was used to calculate the electron temperature with a varying permanent magnet array. Four types of permanent magnet array were simulated to optimize the electron temperature. It was found that a 2-layer full line cusp field (with inverse field) produced the best electron temperature control behavior.

  16. Application and development of ion-source technology for radiation-effects testing of electronics

    Science.gov (United States)

    Kalvas, T.; Javanainen, A.; Kettunen, H.; Koivisto, H.; Tarvainen, O.; Virtanen, A.

    2017-09-01

    Studies of heavy-ion induced single event effect (SEE) on space electronics are necessary to verify the operation of the components in the harsh radiation environment. These studies are conducted by using high-energy heavy-ion beams to simulate the radiation effects in space. The ion beams are accelerated as so-called ion cocktails, containing several ion beam species with similar mass-to-charge ratio, covering a wide range of linear energy transfer (LET) values also present in space. The use of cocktails enables fast switching between beam species during testing. Production of these high-energy ion cocktails poses challenging requirements to the ion sources because in most laboratories reaching the necessary beam energies requires very high charge state ions. There are two main technologies producing these beams: The electron beam ion source EBIS and the electron cyclotron resonance ion source ECRIS. The EBIS is most suitable for pulsed accelerators, while ECRIS is most suitable for use with cyclotrons, which are the most common accelerators used in these applications. At the Accelerator Laboratory of the University of Jyväskylä (JYFL), radiation effects testing is currently performed using a K130 cyclotron and a 14 GHz ECRIS at a beam energy of 9.3 MeV/u. A new 18 GHz ECRIS, pushing the limits of the normal conducting ECR technology is under development at JYFL. The performances of existing 18 GHz ion sources have been compared, and based on this analysis, a 16.2 MeV/u beam cocktail with 1999 MeV 126Xe44+ being the most challenging component to has been chosen for development at JYFL. The properties of the suggested beam cocktail are introduced and discussed.

  17. Studies on the radial dose distribution for clinical electron beams of 9 and 16 MeV using Monte Carlo simulation

    Energy Technology Data Exchange (ETDEWEB)

    Yoriyaz, Helio; Siqueira, Paulo T.D.; Zevallos-Chavez, Juan Y. [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil). Centro de Engenharia Nuclear]. E-mail: hyoriyaz@ipen.br; Furnari, Laura; Poli, Maria Esmeralda R. [Sao Paulo Univ., SP (Brazil). Faculdade de Medicina. Hospital das Clinicas

    2005-07-01

    Radial dose distributions have been obtained for several electron beam field sizes through the Monte Carlo simulation. Measurements were performed by an ionization chamber in a 50x50x50 cm{sup 3} water phantom which is routinely used for calibration. Calculated and measured values were compared to adjust the input energy spectra used for the Monte Carlo simulation. The methodology presented here is part of the 'tuning procedure' for the construction of electron beam sources typically used for radiotherapy. (author)

  18. 78 FR 57395 - Guidance for Industry on Electronic Source Data in Clinical Investigations; Availability

    Science.gov (United States)

    2013-09-18

    ... ``Electronic Source Data in Clinical Investigations.'' This document provides guidance to sponsors, contract... retention of electronic source data in FDA-regulated clinical investigations. This guidance promotes... a guidance for industry entitled ``Electronic Source Data in Clinical Investigations.''...

  19. Development of a Sub-Picosecond Tunable X-Ray Source at the LLNL Electron Linac

    Energy Technology Data Exchange (ETDEWEB)

    Slaughter, D; Springer, P; Le Sage, G; Crane, J; Ditmire, T; Cowan, T; Anderson, S G; Rosenzweig, J B

    2001-08-31

    The use of ultrafast laser pulses to generate very high brightness, ultra short (fs to ps) pulses of x-rays is a topic of great interest to the x-ray user community. In principle, femtosecond-scale pump-probe experiments can be used to temporally resolve structural dynamics of materials on the time scale of atomic motion. The development of sub-ps x-ray pulses will make possible a wide range of materials and plasma physics studies with unprecedented time resolution. A current project at LLNL will provide such a novel x-ray source based on Thomson scattering of high power, short laser pulses with a high peak brightness, relativistic electron bunch. The system is based on a 5 mm-mrad normalized emittance photoinjector, a 100 MeV electron RF linac, and a 300 mJ, 35 fs solid-state laser system. The Thomson x-ray source produces ultra fast pulses with x-ray energies capable of probing into high-Z metals, and a high flux per pulse enabling single shot experiments. The system will also operate at a high repetition rate ({approx} 10 Hz).

  20. Development and characterization of electron sources for diffraction applications

    Energy Technology Data Exchange (ETDEWEB)

    Casandruc, Albert

    2015-12-15

    The dream to control chemical reactions that are essential to life is now closer than ever to gratify. Recent scientific progress has made it possible to investigate phenomena and processes which deploy at the angstroms scale and at rates on the order femtoseconds. Techniques such as Ultrafast Electron Diffraction (UED) are currently able to reveal the spatial atomic configuration of systems with unit cell sizes on the order of a few nanometers with about 100 femtosecond temporal resolution. Still, major advances are needed for structural interrogation of biological systems like protein crystals, which have unit cell sizes of 10 nanometers or larger, and sample sizes of less than one micrometer. For such samples, the performance of these electron-based techniques is now limited by the quality, in particular the brightness, of the electron source. The current Ph.D. work represents a contribution towards the development and the characterization of electron sources which are essential to static and time-resolved electron diffraction techniques. The focus was on electron source fabrication and electron beam characterization measurements, using the solenoid and the aperture scan techniques, but also on the development and maintenance of the relevant experimental setups. As a result, new experimental facilities are now available in the group and, at the same time, novel concepts for generating electron beams for electron diffraction applications have been developed. In terms of existing electron sources, the capability to trigger and detect field emission from single double-gated field emitter Mo tips was successfully proven. These sharp emitter tips promise high brightness electron beams, but for investigating individual such structures, new engineering was needed. Secondly, the influence of the surface electric field on electron beam properties has been systematically performed for flat Mo photocathodes. This study is very valuable especially for state

  1. Electron Beam Collimation for the Next Generation Light Source

    Energy Technology Data Exchange (ETDEWEB)

    Steier, C.; Emma, P.; Nishimura, H.; Papadopoulos, C.; Sannibale, F.

    2013-05-20

    The Next Generation Light Source will deliver high (MHz) repetition rate electron beams to an array of free electron lasers. Because of the significant average current in such a facility, effective beam collimation is extremely important to minimize radiation damage to undulators, prevent quenches of superconducting cavities, limit dose rates outside of the accelerator tunnel and prevent equipment damage. This paper describes the early conceptual design of a collimation system, as well as initial results of simulations to test its effectiveness.

  2. Studies of longitudinal profile of electron bunches and impedance measurements at Indus-2 synchrotron radiation source

    Science.gov (United States)

    Garg, Akash Deep; Yadav, S.; Kumar, Mukesh; Shrivastava, B. B.; Karnewar, A. K.; Ojha, A.; Puntambekar, T. A.

    2016-04-01

    Indus-2 is a 3rd generation synchrotron radiation source at the Raja Ramanna Centre for Advanced Technology (RRCAT) in India. We study the longitudinal profile of electrons in Indus-2 by using dual sweep synchroscan streak camera at visible diagnostic beamline. In this paper, the longitudinal profiles of electron bunch are analyzed by filling beam current in a single bunch mode. These studies are carried at injection energy (550 MeV) and at ramped beam energy (2.5 GeV). The effects of the wakefield generated interactions between the circulating electrons and the surrounding vacuum chamber are analyzed in terms of measured effects on longitudinal beam distribution. The impedance of the storage ring is obtained by fitting the solutions of Haissinski equation to the measured bunch lengthening with different impedance models. The impedance of storage ring obtained by a series R+L impedance model indicates a resistance (R) of 1350±125 Ω, an inductance (L) of 180±25 nH and broadband impedance of 2.69 Ω. These results are also compared with the values obtained from measured synchronous phase advancing and scaling laws. These studies are very useful in better understanding and control of the electromagnetic interactions.

  3. Cross sections of electron loss and capture for beams of O{sup +} in water vapor from the energy range of 0,2 to 1,2 MeV; Secoes de choque de perda e captura eletronica para feixes de O{sup +} em vapor de agua em uma faixa de energia entre 0,2 e 1,2 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Vitor Jesus de

    2015-06-01

    The study of the interactions between atoms and molecules is important for the knowledge of the cross sections of the processes that contribute to the deposition of energy by charged particle beams used in radiotherapy planning and transport particle simulation codes. Heavy ions, such as oxygen, induce many cellular and molecular damages in human cells.as a result of interaction between the projectile and atoms and molecules. The use of proton and carbon as the projectile interacting with water molecules is well characterized, however there are few studies with oxygen ions. In this work we are interested in the study of electron loss (projectile ionization) and electron capture with charge state 1+. The Pelletron accelerator of 1.7 MeV from the Federal University of Rio de Janeiro housed in the Atomic and Molecular collisions Laboratory (LACAM) has been used, which can accelerate atomic and molecular ions up to speeds of the order of hundredths of light speed, and consists of the source of negative ions, the Wien filter, the accelerator itself and the magnet load selector. The detection device used to evaluate the processes of interaction (capture and loss) between the beam of the O{sup +} and the water molecule is a Microchannel Plate (MCP) at the position sensitive anode. The collisions of O{sup +} beans are being studied in the range of 0.2 to 1.2 MeV with water vapor (Z = 10). Were obtained the respective absolute cross sections for electron loss and electron capture and compared with the cross sections of the molecule methane (CH4 → Z = 10), the isoelectronic water molecule. The experimental results show an agreement between the measurements with water and methane. Comparisons were made with results of theoretical models for electron loss using the 'Free Collision Model' and for capture the Bohr and Lindhard model. The theoretical results for electron loss show an agreement of experimental data with the model used. The model of Bohr and Lindhard

  4. Position of the source of particles in solar electron events

    Science.gov (United States)

    Wang, Xue-yi; Huang, Yong-nian

    The ISEE-3 data for 51 solar electron events are analyzed and classified into Fe-rich and Fe-poor events. For Fe-rich events, the source is found to be in the high chromosphere; for the Fe-poor events, in the region between the chromosphere and corona. In both cases the source position differs from the position of the corresponding flare. A process of formation of these two types of events is proposed.

  5. A Stable High-Energy Electron Source from Laser Wakefield Acceleration

    Science.gov (United States)

    Zhang, Ping; Zhao, Baozhen; Liu, Cheng; Yan, Wenchao; Golovin, Grigory; Banerjee, Sudeep; Chen, Shouyuan; Haden, Daniel; Fruhling, Colton; Umstadter, Donald

    2016-10-01

    The stability of the electron source from laser wake-field acceleration (LWFA) is essential for applications, such as novel x-ray sources and fundamental experiments in high field physics. To obtain such a stable source, we used an optimal laser pulse and a novel gas nozzle. The high-power laser pulse on target was focused to a diffraction-limited spot by the use of adaptive wavefront correction and the pulse duration was transform limited by the use of spectral feedback control. An innovative design for the nozzle led to a stable, flat-top profile with diameters of 4 mm and 8 mm with a high Mach-number ( 6). In experiments to generate high-energy electron beams by LWFA, we were able to obtain reproducible results with beam energy of 800 MeV and charge >10 pC. Higher charge but broader energy spectrum resulted when the plasma density was increased. These developments have resulted in a laser-driven wakefield accelerator that is stable and robust. With this device, we show that narrowband high-energy x-rays beams can be generated by the inverse-Compton scattering process. This accelerator has also been used in recent experiments to study nonlinear effects in the interaction of high-energy electron beams with ultraintense laser pulses. This material is based upon work supported by NSF No. PHY-153700; US DOE, Office of Science, BES, # DE-FG02-05ER15663; AFOSR # FA9550-11-1-0157; and DHS DNDO # HSHQDC-13-C-B0036.

  6. An image-based skeletal dosimetry model for the ICRP reference newborn-internal electron sources

    Energy Technology Data Exchange (ETDEWEB)

    Pafundi, Deanna; Lee, Choonsik; Bolch, Wesley [Department of Nuclear and Radiological Engineering, University of Florida, Gainesville, FL (United States); Rajon, Didier [Department of Neurosurgery, University of Florida, Gainesville, FL (United States); Jokisch, Derek [Department of Physics and Astronomy, Francis Marion University, Florence, SC (United States)], E-mail: wbolch@ufl.edu

    2010-04-07

    In this study, a comprehensive electron dosimetry model of newborn skeletal tissues is presented. The model is constructed using the University of Florida newborn hybrid phantom of Lee et al (2007 Phys. Med. Biol. 52 3309-33), the newborn skeletal tissue model of Pafundi et al (2009 Phys. Med. Biol. 54 4497-531) and the EGSnrc-based Paired Image Radiation Transport code of Shah et al (2005 J. Nucl. Med. 46 344-53). Target tissues include the active bone marrow (surrogate tissue for hematopoietic stem cells), shallow marrow (surrogate tissue for osteoprogenitor cells) and unossified cartilage (surrogate tissue for chondrocytes). Monoenergetic electron emissions are considered over the energy range 1 keV to 10 MeV for the following source tissues: active marrow, trabecular bone (surfaces and volumes), cortical bone (surfaces and volumes) and cartilage. Transport results are reported as specific absorbed fractions according to the MIRD schema and are given as skeletal-averaged values in the paper with bone-specific values reported in both tabular and graphic format as electronic annexes (supplementary data). The method utilized in this work uniquely includes (1) explicit accounting for the finite size and shape of newborn ossification centers (spongiosa regions), (2) explicit accounting for active and shallow marrow dose from electron emissions in cortical bone as well as sites of unossified cartilage, (3) proper accounting of the distribution of trabecular and cortical volumes and surfaces in the newborn skeleton when considering mineral bone sources and (4) explicit consideration of the marrow cellularity changes for active marrow self-irradiation as applicable to radionuclide therapy of diseased marrow in the newborn child.

  7. Potential applications of an electron cyclotron resonance multicusp plasma source

    Energy Technology Data Exchange (ETDEWEB)

    Tsai, C.C.; Berry, L.A.; Gorbatkin, S.M.; Haselton, H.H.; Roberto, J.B.; Stirling, W.L. (Oak Ridge National Laboratory, Oak Ridge, TN (USA))

    1990-05-01

    An electron cyclotron resonance (ECR) multicusp plasmatron has been developed by feeding a multicusp bucket arc chamber with a compact ECR plasma source. This novel source produces large (about 25 cm diam), uniform (to within {plus minus}10%), dense ({gt}10{sup 11} cm{sup {minus}3}) plasmas of argon, helium, hydrogen, and oxygen. It has been operated to produce an oxygen plasma for etching 12.7 cm (5 in.) positive photoresist-coated silicon wafers with uniformity within {plus minus}8%. Results and potential applications of this new ECR plasma source for plasma processing of thin films are discussed.

  8. Power Electronics as Efficient Interface of Renewable Energy Sources

    DEFF Research Database (Denmark)

    Blaabjerg, Frede; Chen, Zhe; Kjær, Søren Bækhøj

    2004-01-01

    renewable energy conversion system, will play an important part in our future energy supply. But other sources like microturbines, photovoltaics and fuel cell systems may also be serious contributor to the power supply. Characteristically, power electronics will be an efficient and important interface...

  9. Free Open Source Software in Electronics Engineering Education: A Survey

    Directory of Open Access Journals (Sweden)

    Vijay Nehra

    2014-05-01

    Full Text Available Since the last two decades, much attention has been paid to Electronics Engineering (EE education in India. Various commercial software tools and simulator such as mathematical application packages, electronics CAD tools, learning management systems, multimedia tools and general purpose tools supports EE education. Traditionally, proprietary software packages such as OrCAD Pspice, MATLAB, LabView, Multisim and others too are widely practiced and well integrated in electronics engineering curricula of various Universities nationwide. In today’s market, there are plenty of software tools and packages; however, most of them are expensive. The high cost of standard commercial packages is often hardship for students and faculties. Selecting various appropriate tools for academic use is considered as one of the key challenges in EE education. Over recent years, an alternative trend based on Free Open Source Software (FOSS has gained momentum in higher education due to several benefits such as cost, license management flexibility, access to source code, security and stability etc. Presently, a plethora of open source software tools and resource related to EE can be deployed in teaching and learning process of EE education. In this communication, a short exposition of Free Open Source Software useful in electronics engineering education and research is presented. A brief outlook of FOSS packages, their web addresses and major highlights are also presented. The overall aim of this paper is to create awareness among instructors and students to impart active and self learning using FOSS.

  10. Source point calibration from an arbitrary electron backscattering pattern

    DEFF Research Database (Denmark)

    Lassen, Niels Christian Krieger

    1999-01-01

    Precise knowledge of the position of the source point is a requirement if electron backscattering patterns (EBSPs) are to be used for crystal orientation measurements or other types of measurements which demand a geometrical analysis of the patterns. Today, possibly the most popular method...

  11. Towards Evidence-Based Understanding of Electronic Data Sources

    DEFF Research Database (Denmark)

    Chen, Lianping; Ali Babar, Muhammad; Zhang, He

    2010-01-01

    Identifying relevant papers from various Electronic Data Sources (EDS) is one of the key activities of conducting these kinds of studies. Hence, the selection of EDS for searching the potentially relevant papers is an important decision, which can affect a study’s coverage of relevant papers. Res...

  12. Biprism Electron Interferometry with a Single Atom Tip Source

    CERN Document Server

    Schütz, Georg; Pooch, Andreas; Meier, Simon; Schneeweiss, Philipp; Rauschenbeutel, Arno; Günther, Andreas; Chang, Wei-Tse; Hwang, Ing-Shouh; Stibor, Alexander

    2013-01-01

    Experiments with electron or ion matter waves require a coherent, monochromatic and long-term stable source with high brightness. These requirements are best fulfilled by single atom tip (SAT) field emitters. The performance of an iridium covered W(111) SAT is demonstrated and analyzed for electrons in a biprism interferometer. Furthermore we characterize the emission of the SAT in a separate field electron and field ion microscope and compare it with other emitter types. A new method is presented to fabricate the electrostatic charged biprism wire that separates and combines the matter wave. In contrast to other biprism interferometers the source and the biprism size are well defined within a few nanometers. The setup has direct applications in ion interferometry and Aharonov-Bohm physics.

  13. 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.

  14. A bremsstrahlung gamma-ray source based on stable ionization injection of electrons into a laser wakefield accelerator

    Science.gov (United States)

    Döpp, A.; Guillaume, E.; Thaury, C.; Lifschitz, A.; Sylla, F.; Goddet, J.-P.; Tafzi, A.; Iaquanello, G.; Lefrou, T.; Rousseau, P.; Conejero, E.; Ruiz, C.; Ta Phuoc, K.; Malka, V.

    2016-09-01

    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.

  15. Single Crystal Diamond Needle as Point Electron Source

    Science.gov (United States)

    Kleshch, Victor I.; Purcell, Stephen T.; Obraztsov, Alexander N.

    2016-10-01

    Diamond has been considered to be one of the most attractive materials for cold-cathode applications during past two decades. However, its real application is hampered by the necessity to provide appropriate amount and transport of electrons to emitter surface which is usually achieved by using nanometer size or highly defective crystallites having much lower physical characteristics than the ideal diamond. Here, for the first time the use of single crystal diamond emitter with high aspect ratio as a point electron source is reported. Single crystal diamond needles were obtained by selective oxidation of polycrystalline diamond films produced by plasma enhanced chemical vapor deposition. Field emission currents and total electron energy distributions were measured for individual diamond needles as functions of extraction voltage and temperature. The needles demonstrate current saturation phenomenon and sensitivity of emission to temperature. The analysis of the voltage drops measured via electron energy analyzer shows that the conduction is provided by the surface of the diamond needles and is governed by Poole-Frenkel transport mechanism with characteristic trap energy of 0.2-0.3 eV. The temperature-sensitive FE characteristics of the diamond needles are of great interest for production of the point electron beam sources and sensors for vacuum electronics.

  16. Improved Nonambipolar Electron Source Operation with Permanent Magnets

    Science.gov (United States)

    Gudmundson, Jesse; Hershkowitz, Noah

    2008-11-01

    The Nonambipolar Electron Source (NES) is a Radio Frequency (rf) plasma-based electron source that does not rely on electron emission at a cathode surface. All electrons are extracted at an electron sheath through a biased ring and all ions are lost radially to a biased Faraday shield. An electromagnet in the original NES has been replaced by a NdFeB permanent magnet array. A portion of the magnet array consists of a ring of radially aligned magnets followed by a ring of axially aligned magnets that produce a peak field of approximately 800 Gauss. Axial magnetic field strength at the extraction ring was increased using an additional ring of axially aligned magnets. Measurement of the magnetic field was in good agreement with field predicted by the FEMM (Finite Element Method Magnetics) code. Optimization of the single turn antenna and biased ring position in the magnetic field will be discussed. At least 15 A of electron current was extracted using a flow rate of 15 sccm Ar at 600 W of rf power at 13.56 MHz. For comparison, the original NES required 1200 W of power to achieve 15 A of extracted current. Compared to the previous coil design, the NdFeB magnets are lighter weight and require no power.

  17. Electron beam ion source and electron beam ion trap (invited)a)

    Science.gov (United States)

    Becker, Reinard; Kester, Oliver

    2010-02-01

    The electron beam ion source (EBIS) and its trap variant [electron beam ion trap (EBIT)] celebrated their 40th and 20th anniversary, respectively, at the EBIS/T Symposium 2007 in Heidelberg. These technologically challenging sources of highly charged ions have seen a broad development in many countries over the last decades. In contrast to most other ion sources the recipe of improvement was not "sorcery" but a clear understanding of the physical laws and obeying the technological constraints. This review will report important achievements of the past as well as promising developments in the future.

  18. First test of BNL electron beam ion source with high current density electron beam

    Science.gov (United States)

    Pikin, Alexander; Alessi, James G.; Beebe, Edward N.; Shornikov, Andrey; Mertzig, Robert; Wenander, Fredrik; Scrivens, Richard

    2015-01-01

    A new electron gun with electrostatic compression has been installed at the Electron Beam Ion Source (EBIS) Test Stand at BNL. This is a collaborative effort by BNL and CERN teams with a common goal to study an EBIS with electron beam current up to 10 A, current density up to 10,000 A/cm2 and energy more than 50 keV. Intensive and pure beams of heavy highly charged ions with mass-to-charge ratio heavy ion research facilities including NASA Space Radiation Laboratory (NSRL) at BNL and HIE-ISOLDE at CERN. With a multiampere electron gun, the EBIS should be capable of delivering highly charged ions for both RHIC facility applications at BNL and for ISOLDE experiments at CERN. Details of the electron gun simulations and design, and the Test EBIS electrostatic and magnetostatic structures with the new electron gun are presented. The experimental results of the electron beam transmission are given.

  19. Controlled generation of comb-like electron beams in plasma channels for polychromatic inverse Thomson γ-ray sources

    Science.gov (United States)

    Kalmykov, S. Y.; Davoine, X.; Ghebregziabher, I.; Lehe, R.; Lifschitz, A. F.; Shadwick, B. A.

    2016-03-01

    Propagating a relativistically intense, negatively chirped laser pulse (the bandwidth  >150 nm) in a plasma channel makes it possible to generate background-free, comb-like electron beams—sequences of synchronized bunches with a low phase-space volume and controlled energy spacing. The tail of the pulse, confined in the accelerator cavity (an electron density ‘bubble’), experiences periodic focusing, while the head, which is the most intense portion of the pulse, steadily self-guides. Oscillations of the cavity size cause periodic injection of electrons from the ambient plasma, creating an electron energy comb with the number of components, their mean energy, and energy spacing dependent on the channel radius and pulse length. These customizable electron beams enable the design of a tunable, all-optical source of pulsed, polychromatic γ-rays using the mechanism of inverse Thomson scattering, with up to  ˜10-5 conversion efficiency from the drive pulse in the electron accelerator to the γ-ray beam. Such a source may radiate  ˜107 quasi-monochromatic photons per shot into a microsteradian-scale cone. The photon energy is distributed among several distinct bands, each having sub-30% energy spread, with a highest energy of 12.5 MeV.

  20. High dielectric constant ceramics for ion-electron sources

    CERN Document Server

    Boscolo, I

    2002-01-01

    Ferroelectric disks, coated with proper electrodes, can easily produce a dense plasma cloud when excited with a high-voltage pulse. This plasma can be a source of either electrons or ions depending on the sign of the extracting field set in front of the disk. We present the behavior of the disks operating at high frequency as emitters of both electrons and ions in two experimental configurations: (a) without and (b) with two screening grids. These two screening grids are inserted when the plasma must be confined within the cathode region. The system is capable of providing ion pulses of a few hundred milliamperes, whose length can range from a hundred nanoseconds to dozen microseconds. The electron pulses of energetic electrons have typically an amplitude higher than a couple of amperes. Tests at MHz repetition rate were positive as for stable operation.

  1. The development of a 200 kV monochromated field emission electron source

    Energy Technology Data Exchange (ETDEWEB)

    Mukai, Masaki, E-mail: mmukai@jeol.co.jp [JEOL Ltd., 3-1-2 Musashino, Akishima, Tokyo 196-8558 (Japan); Kim, Judy S. [University of Oxford, Department of Materials, Parks Road, Oxford, OX1 3PH (United Kingdom); Omoto, Kazuya; Sawada, Hidetaka; Kimura, Atsushi; Ikeda, Akihiro; Zhou, Jun; Kaneyama, Toshikatsu [JEOL Ltd., 3-1-2 Musashino, Akishima, Tokyo 196-8558 (Japan); Young, Neil P.; Warner, Jamie H.; Nellist, Peter D.; Kirkland, Angus I. [University of Oxford, Department of Materials, Parks Road, Oxford, OX1 3PH (United Kingdom)

    2014-05-01

    We report the development of a monochromator for an intermediate-voltage aberration-corrected electron microscope suitable for operation in both STEM and TEM imaging modes. The monochromator consists of two Wien filters with a variable energy selecting slit located between them and is located prior to the accelerator. The second filter cancels the energy dispersion produced by the first filter and after energy selection forms a round monochromated, achromatic probe at the specimen plane. The ultimate achievable energy resolution has been measured as 36 meV at 200 kV and 26 meV at 80 kV. High-resolution Annular Dark Field STEM images recorded using a monochromated probe resolve Si–Si spacings of 135.8 pm using energy spreads of 218 meV at 200 kV and 217 meV at 80 kV respectively. In TEM mode an improvement in non-linear spatial resolution to 64 pm due to the reduction in the effects of partial temporal coherence has been demonstrated using broad beam illumination with an energy spread of 134 meV at 200 kV. - Highlights: • Monochromator for 200 kV aberration corrected TEM and STEM was developed. • Monochromator produces monochromated and achromatic probe at specimen plane. • Ultimate energy resolution was measured to be 36 meV at 200 kV and 26 meV at 80 kV. • Atomic resolution STEM images were recorded using monochromated electron probe. • Improvements of TEM resolution were confirmed using monochromated illumination.

  2. Measurement of the total cross sections for electron capture of 2. 0-7. 5 MeV H/sup +/ in H, H/sub 2/ and He

    Energy Technology Data Exchange (ETDEWEB)

    Schwab, W.; Baptista, G.B.; Justiniano, E.; Vogt, H.; Weber, E.W.; Schuch, R.

    1987-06-28

    The total cross sections for electron capture of protons in atomic and molecular hydrogen and in helium gas targets are measured in the high proton velocity regime of 2.0, 3.5, 5.0 and 7.5 MeV. The results are compared with first- and higher-order perturbation theories (Oppenheimer-Brinkmann-Kramers, true first Born approximation (TFBA), eikonal approximation (EA), continuum distorted wave (CDW), strong potential Born, strong potential Born full peaking) for electron capture, and are found to be in good agreement with the CDW, EA and TFBA approximations.

  3. Application of electron paramagnetic resonance imaging to the characterization of the Ultem(R) exposed to 1 MeV electrons. Correlation of radical density data to tiger code calculations

    Science.gov (United States)

    Suleman, Naushadalli K.

    1994-12-01

    A major long-term goal of the Materials Division at the NASA Langley Research Center is the characterization of new high-performance materials that have potential applications in the aircraft industry, and in space. The materials used for space applications are often subjected to a harsh and potentially damaging radiation environment. The present study constitutes the application of a novel technique to obtain reliable data for ascertaining the molecular basis for the resilience and durability of materials that have been exposed to simulated space radiations. The radiations of greatest concern are energetic electrons and protons, as well as galactic cosmic rays. Presently, the effects of such radiation on matter are not understood in their entirety. It is clear however, that electron radiation causes ionization and homolytic bond rupture, resulting in the formation of paramagnetic spin centers in the polymer matrices of the structural materials. Since the detection and structure elucidation of paramagnetic species are most readily accomplished using Electron Paramagnetic Resonance (EPR) Spectroscopy, the NASA LaRC EPR system was brought back on-line during the 1991 ASEE term. The subsequent 1992 ASEE term was devoted to the adaptation of the EPR core system to meet the requirements for EPR Imaging (EPRI), which provides detailed information on the spatial distribution of paramagnetic species in bulk media. The present (1994) ASEE term was devoted to the calibration of this EPR Imaging system, as well as to the application of this technology to study the effects of electron irradiation on Ultem(exp R), a high performance polymer which is a candidate for applications in aerospace. The Ultem was exposed to a dose of 2.4 x 10(exp 9) Rads (1-MeV energy/electron) at the LaRC electron accelerator facility. Subsequently, the exposed specimens were stored in liquid nitrogen, until immediately prior to analyses by EPRI. The intensity and dimensions of the EPR Images that

  4. Application of electron paramagnetic resonance imaging to the characterization of the Ultem(R) exposed to 1 MeV electrons. Correlation of radical density data to tiger code calculations

    Science.gov (United States)

    Suleman, Naushadalli K.

    1994-01-01

    A major long-term goal of the Materials Division at the NASA Langley Research Center is the characterization of new high-performance materials that have potential applications in the aircraft industry, and in space. The materials used for space applications are often subjected to a harsh and potentially damaging radiation environment. The present study constitutes the application of a novel technique to obtain reliable data for ascertaining the molecular basis for the resilience and durability of materials that have been exposed to simulated space radiations. The radiations of greatest concern are energetic electrons and protons, as well as galactic cosmic rays. Presently, the effects of such radiation on matter are not understood in their entirety. It is clear however, that electron radiation causes ionization and homolytic bond rupture, resulting in the formation of paramagnetic spin centers in the polymer matrices of the structural materials. Since the detection and structure elucidation of paramagnetic species are most readily accomplished using Electron Paramagnetic Resonance (EPR) Spectroscopy, the NASA LaRC EPR system was brought back on-line during the 1991 ASEE term. The subsequent 1992 ASEE term was devoted to the adaptation of the EPR core system to meet the requirements for EPR Imaging (EPRI), which provides detailed information on the spatial distribution of paramagnetic species in bulk media. The present (1994) ASEE term was devoted to the calibration of this EPR Imaging system, as well as to the application of this technology to study the effects of electron irradiation on Ultem(exp R), a high performance polymer which is a candidate for applications in aerospace. The Ultem was exposed to a dose of 2.4 x 10(exp 9) Rads (1-MeV energy/electron) at the LaRC electron accelerator facility. Subsequently, the exposed specimens were stored in liquid nitrogen, until immediately prior to analyses by EPRI. The intensity and dimensions of the EPR Images that

  5. Electron string ion sources for carbon ion cancer therapy accelerators

    CERN Document Server

    Boytsov, A Yu; Donets, E D; Donets, E E; Katagiri, K; Noda, K; Ponkin, D O; Ramzdorf, A Yu; Salnikov, V V; Shutov, V B

    2015-01-01

    The Electron String type of Ion Sources (ESIS) was developed, constructed and tested first in the Joint Institute for Nuclear Research. These ion sources can be the appropriate sources for production of pulsed C4+ and C6+ ion beams which can be used for cancer therapy accelerators. In fact the test ESIS Krion-6T already now at the solenoid magnetic field only 4.6 T provides more than 10^10 C4+ ions per pulse and about 5*10^9 C6+ ions per pulse. Such ion sources could be suitable for application at synchrotrons. It was also found, that Krion-6T can provide more than 10^11 C6+ ions per second at 100 Hz repetition rate, and the repetition rate can be increased at the same or larger ion output per second. This makes ESIS applicable at cyclotrons as well. As for production of 11C radioactive ion beams ESIS can be the most economic kind of ion source. To proof that the special cryogenic cell for pulse injection of gaseous species into electron string was successfully tested using the ESIS Krion-2M.

  6. Crystallographic data processing for free-electron laser sources

    Energy Technology Data Exchange (ETDEWEB)

    White, Thomas A., E-mail: taw@physics.org; Barty, Anton; Stellato, Francesco [DESY, Notkestrasse 85, 22607 Hamburg (Germany); Holton, James M. [University of California, San Francisco, CA 94158 (United States); Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Kirian, Richard A. [DESY, Notkestrasse 85, 22607 Hamburg (Germany); Arizona State University, Tempe, AZ 85287 (United States); Zatsepin, Nadia A. [Arizona State University, Tempe, AZ 85287 (United States); Chapman, Henry N. [DESY, Notkestrasse 85, 22607 Hamburg (Germany); University of Hamburg, Luruper Chaussee 149, 22761 Hamburg (Germany)

    2013-07-01

    A processing pipeline for diffraction data acquired using the ‘serial crystallography’ methodology with a free-electron laser source is described with reference to the crystallographic analysis suite CrystFEL and the pre-processing program Cheetah. A processing pipeline for diffraction data acquired using the ‘serial crystallography’ methodology with a free-electron laser source is described with reference to the crystallographic analysis suite CrystFEL and the pre-processing program Cheetah. A detailed analysis of the nature and impact of indexing ambiguities is presented. Simulations of the Monte Carlo integration scheme, which accounts for the partially recorded nature of the diffraction intensities, are presented and show that the integration of partial reflections could be made to converge more quickly if the bandwidth of the X-rays were to be increased by a small amount or if a slight convergence angle were introduced into the incident beam.

  7. Electron dynamics in RF sources with a laser controlled emission

    CERN Document Server

    Khodak, I V; Metrochenko, V V

    2001-01-01

    Photoemission radiofrequency (RF) electron sources are sources of electron beams with extremely high brightness. Beam bunching processes in such devices are well studied in case when laser pulse duration is much lower of rf oscillation period.At the same time photoemission RF guns have some merits when operating in 'long-pulse' mode. In this case the laser pulse duration is much higher of rf oscillation period but much lower of rise time of oscillations in a gun cavity. Beam parameters at the gun output are compared for photoemission and thermoemission cathode applications. The paper presents results of a beam dynamics simulation in such guns with different resonance structures. Questions connected with defining of the current pulse peak value that can be obtained in such guns are discussed.

  8. 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.

  9. 77 FR 69632 - Draft Guidance for Industry on Electronic Source Data in Clinical Investigations; Availability

    Science.gov (United States)

    2012-11-20

    ... entitled ``Electronic Source Data in Clinical Investigations.'' This document revises and updates the draft... in FDA- regulated clinical investigations. The revised draft guidance promotes capturing source data... draft guidance for industry entitled ``Electronic Source Data in Clinical Investigations.''...

  10. Oscillating plasma bubbles. III. Internal electron sources and sinks

    Energy Technology Data Exchange (ETDEWEB)

    Stenzel, R. L.; Urrutia, J. M. [Department of Physics and Astronomy, University of California, Los Angeles, California 90095-1547 (United States)

    2012-08-15

    An internal electron source has been used to neutralize ions injected from an ambient plasma into a spherical grid. The resultant plasma is termed a plasma 'bubble.' When the electron supply from the filament is reduced, the sheath inside the bubble becomes unstable. The plasma potential of the bubble oscillates near but below the ion plasma frequency. Different modes of oscillations have been observed as well as a subharmonic and multiple harmonics. The frequency increases with ion density and decreases with electron density. The peak amplitude occurs for an optimum current and the instability is quenched at large electron densities. The frequency also increases if Langmuir probes inside the bubble draw electrons. Allowing electrons from the ambient plasma to enter, the bubble changes the frequency dependence on grid voltage. It is concluded that the net space charge density in the sheath determines the oscillation frequency. It is suggested that the sheath instability is caused by ion inertia in an oscillating sheath electric field which is created by ion bunching.

  11. Special Relativity, the Source of Electron Deep Orbits

    Science.gov (United States)

    Paillet, J. L.; Meulenberg, A.

    2017-02-01

    In this paper, we explicitly point out the reasons why Special Relativity must be considered as the source of electron deep orbits, and dominates their behavior. We show that the cause is the quadratic form of the relativistic expression of energy, and this clearly appears when we explicitly develop the relativistic Schrödinger equation and compare it with the non-relativistic one.

  12. A bremsstrahlung gamma-ray source based on stable ionization injection of electrons into a laser wakefield accelerator

    CERN Document Server

    Döpp, A; Thaury, C; Lifschitz, A; Sylla, F; Goddet, J-P; Tafzi, A; Iaquanello, G; Lefrou, T; Rousseau, P; Conejero, E; Ruiz, C; Phuoc, K Ta; Malka, V

    2016-01-01

    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 linear 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 wit...

  13. Juno/JEDI observations of 0.01 to >10 MeV energetic ions in the Jovian auroral regions: Anticipating a source for polar X-ray emission

    Science.gov (United States)

    Haggerty, D. K.; Mauk, B. H.; Paranicas, C. P.; Clark, G.; Kollmann, P.; Rymer, A. M.; Bolton, S. J.; Connerney, J. E. P.; Levin, S. M.

    2017-07-01

    After a successful orbit insertion, the Juno spacecraft completed its first 53.5 day orbit and entered a very low altitude perijove with the full scientific payload operational for the first time on 27 August 2016. The Jupiter Energetic particle Detector Instrument measured ions and electrons over the auroral regions and through closest approach, with ions measured from 0.01 to >10 MeV, depending on species. This report focuses on the composition of the energetic ions observed during the first perijove of the Juno mission. Of particular interest are the ions that precipitate from the magnetosphere onto the polar atmosphere and ions that are accelerated locally by Jupiter's powerful auroral processes. We report preliminary findings on the spatial variations, species, including energy and pitch angle distributions throughout the prime science region during the first orbit of the Juno mission. The prime motivation for this work was to examine the heavy ions that are thought to be responsible for the observed polar X-rays. Jupiter Energetic particle Detector Instrument (JEDI) did observe precipitating heavy ions with energies >10 MeV, but for this perijove the intensities were far below those needed to account for previously observed polar X-ray emissions. During this survey we also found an unusual signal of ions between oxygen and sulfur. We include here a report on what appears to be a transitory observation of magnesium, or possibly sodium, at MeV energies through closest approach.

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

    CERN Document Server

    Gushenets, V I

    2001-01-01

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

  15. Prediction of the photoluminescence of In0.53Ga0.47As/InP irradiated by 1 MeV electron

    Science.gov (United States)

    Changshi, Liu

    2017-01-01

    Minimizing the impact of radiation-induced degradation on light source and optoelectronic devices based on the In0.53Ga0.47As/InP (InGaAs/InP) plays an important role in their applications. The first objective of this work is to measure the photoluminescence (PL) intensity of InGAs/InP before and after electron radiation. Electron fluence (0-9 × 1014 electrons/cm2)-dependent PL of InGaAs/InP in the range of free- and bound-exciton emission is presented. The experimental results show that the PL intensity of InGaAs/InP is decreased with increasing fluence and more electron-induced defects occurred in the InGaAs/InP hetero-junction than in the InGaAs/InP quantum well. The wavelength dependence of the PL intensity was then fitted using the "Asym2Sig" equation as an asymmetric double sigmoidal function, and the coefficients obtained show reasonable agreement with the experimental data. The strongest bound-exaction line with a width (full width at half-maximum) exhibited a thermal activation energy of approximately 0.71 eV for the InGaAs/InP hetero-junction, while it was not observed of InGaAs/InP quantum well. Moreover, the influence of fluence on the PL intensity was explained with the mathematical method in this work, which enables the prediction of the PL intensity of InGaAs/InP through wavelength and fluence.

  16. Prediction of the photoluminescence of In{sub 0.53}Ga{sub 0.47}As/InP irradiated by 1 MeV electron

    Energy Technology Data Exchange (ETDEWEB)

    Changshi, Liu, E-mail: lcswl@mail.zjxu.edu.cn

    2017-01-15

    Highlights: • The PL intensity of InGaAs/In can be predicted by wavelength. • The influence of radiation fluence on PL intensity of InGaAs/In is explained, mathematically. • Good application results are obtained. - Abstract: Minimizing the impact of radiation-induced degradation on light source and optoelectronic devices based on the In{sub 0.53}Ga{sub 0.47}As/InP (InGaAs/InP) plays an important role in their applications. The first objective of this work is to measure the photoluminescence (PL) intensity of InGAs/InP before and after electron radiation. Electron fluence (0–9 × 10{sup 14} electrons/cm{sup 2})-dependent PL of InGaAs/InP in the range of free- and bound-exciton emission is presented. The experimental results show that the PL intensity of InGaAs/InP is decreased with increasing fluence and more electron-induced defects occurred in the InGaAs/InP hetero-junction than in the InGaAs/InP quantum well. The wavelength dependence of the PL intensity was then fitted using the “Asym2Sig” equation as an asymmetric double sigmoidal function, and the coefficients obtained show reasonable agreement with the experimental data. The strongest bound-exaction line with a width (full width at half-maximum) exhibited a thermal activation energy of approximately 0.71 eV for the InGaAs/InP hetero-junction, while it was not observed of InGaAs/InP quantum well. Moreover, the influence of fluence on the PL intensity was explained with the mathematical method in this work, which enables the prediction of the PL intensity of InGaAs/InP through wavelength and fluence.

  17. Laser ion source with solenoid for Brookhaven National Laboratory-electron beam ion source.

    Science.gov (United States)

    Kondo, K; Yamamoto, T; Sekine, M; Okamura, M

    2012-02-01

    The electron beam ion source (EBIS) preinjector at Brookhaven National Laboratory (BNL) is a new heavy ion-preinjector for relativistic heavy ion collider (RHIC) and NASA Space Radiation Laboratory (NSRL). Laser ion source (LIS) is a primary ion source provider for the BNL-EBIS. LIS with solenoid at the plasma drift section can realize the low peak current (∼100 μA) with high charge (∼10 nC) which is the BNL-EBIS requirement. The gap between two solenoids does not cause serious plasma current decay, which helps us to make up the BNL-EBIS beamline.

  18. Open source electronic health records and chronic disease management.

    Science.gov (United States)

    Goldwater, Jason C; Kwon, Nancy J; Nathanson, Ashley; Muckle, Alison E; Brown, Alexa; Cornejo, Kerri

    2014-02-01

    To study and report on the use of open source electronic health records (EHR) to assist with chronic care management within safety net medical settings, such as community health centers (CHC). The study was conducted by NORC at the University of Chicago from April to September 2010. The NORC team undertook a comprehensive environmental scan, including a literature review, a dozen key informant interviews using a semistructured protocol, and a series of site visits to CHC that currently use an open source EHR. Two of the sites chosen by NORC were actively using an open source EHR to assist in the redesign of their care delivery system to support more effective chronic disease management. This included incorporating the chronic care model into an CHC and using the EHR to help facilitate its elements, such as care teams for patients, in addition to maintaining health records on indigent populations, such as tuberculosis status on homeless patients. The ability to modify the open-source EHR to adapt to the CHC environment and leverage the ecosystem of providers and users to assist in this process provided significant advantages in chronic care management. Improvements in diabetes management, controlled hypertension and increases in tuberculosis vaccinations were assisted through the use of these open source systems. The flexibility and adaptability of open source EHR demonstrated its utility and viability in the provision of necessary and needed chronic disease care among populations served by CHC.

  19. Multicusp type Electron Cyclotron Resonance ion source for plasma processing

    Energy Technology Data Exchange (ETDEWEB)

    Amemiya, Hiroshi; Shigueoka, Yoshyuki (Institute of Physical and Chemical Research, Wako, Saitama (Japan)); Ishii, Shigeyuki

    1991-02-01

    A multi-cusp type ECR (electron cyclotron resonance) ion source is built with use of SmCo magnets and 2.45 GHz-TE{sub 11} circular mode microwave. The ion source is operated at pressures from 10{sup -4} to 10{sup -3} Torr with the input microwave power from 100 to 400 W. In hydrogen, the current density of H{sup +} is higher than those of H{sub 2}{sup +} and H{sub 3}{sup +}. The dependence of the fraction of each ion species on the power and pressure is measured and explained by rate equations. The source is operated also in other gases. Mass spectra in He, N{sub 2}, O{sub 2}, Ar and CH{sub 4} are shown together with the pressure and power dependences. Multicharged state of up to 3 has been obtained. (author).

  20. Numerical model of electron cyclotron resonance ion source

    Directory of Open Access Journals (Sweden)

    V. Mironov

    2015-12-01

    Full Text Available Important features of the electron cyclotron resonance ion source (ECRIS operation are accurately reproduced with a numerical code. The code uses the particle-in-cell technique to model the dynamics of ions in ECRIS plasma. It is shown that a gas dynamical ion confinement mechanism is sufficient to provide the ion production rates in ECRIS close to the experimentally observed values. Extracted ion currents are calculated and compared to the experiment for a few sources. Changes in the simulated extracted ion currents are obtained with varying the gas flow into the source chamber and the microwave power. Empirical scaling laws for ECRIS design are studied and the underlying physical effects are discussed.

  1. Power Electronics as Efficient Interface of Renewable Energy Sources

    DEFF Research Database (Denmark)

    Blaabjerg, Frede; Chen, Zhe; Kjær, Søren Bækhøj

    2004-01-01

    The global electrical energy consumption is steadily rising and consequently there is a demand to increase the power generation capacity. A significant percentage of the required capacity increase can be based on renewable energy sources. Wind turbine technology, as the most cost effective...... renewable energy conversion system, will play an important part in our future energy supply. But other sources like microturbines, photovoltaics and fuel cell systems may also be serious contributor to the power supply. Characteristically, power electronics will be an efficient and important interface...... to the grid and this paper will first briefly discuss three different alternative/ renewable energy sources. Next, various configurations of the wind turbine technology are presented, as this technology seems to be most developed and cost-effective. Finally, the developments and requirements from the grid...

  2. Ion optics of RHIC electron beam ion source

    Energy Technology Data Exchange (ETDEWEB)

    Pikin, A.; Alessi, J.; Beebe, E.; Kponou, A.; Okamura, M.; Raparia, D.; Ritter, J.; Tan, Y. [Brookhaven National Laboratory, Upton, New York 11973 (United States); Kuznetsov, G. [Budker Institute of Nuclear Physics, Novosibirsk 630090 (Russian Federation)

    2012-02-15

    RHIC electron beam ion source has been commissioned to operate as a versatile ion source on RHIC injection facility supplying ion species from He to Au for Booster. Except for light gaseous elements RHIC EBIS employs ion injection from several external primary ion sources. With electrostatic optics fast switching from one ion species to another can be done on a pulse to pulse mode. The design of an ion optical structure and the results of simulations for different ion species are presented. In the choice of optical elements special attention was paid to spherical aberrations for high-current space charge dominated ion beams. The combination of a gridded lens and a magnet lens in LEBT provides flexibility of optical control for a wide range of ion species to satisfy acceptance parameters of RFQ. The results of ion transmission measurements are presented.

  3. Exposure of space electronics and materials to ionizing radiation

    DEFF Research Database (Denmark)

    Korsbech, Uffe C C

    1996-01-01

    Describes the methods and sources available for irradiation of space instruments developed at the Department of Automation. Methods for calculations and measurements of fluences and doses are also described. The sources are gamma-rays from iridium-192 and cobalt-60, 30 MeV protons, 10 MeV electrons...

  4. On the application of quantum transport theory to electron sources

    Energy Technology Data Exchange (ETDEWEB)

    Jensen, K.L

    2003-05-15

    Electron sources (e.g., field emitter arrays, wide band-gap (WBG) semiconductor materials and coatings, carbon nanotubes, etc.) seek to exploit ballistic transport within the vacuum after emission from microfabricated structures. Regardless of kind, all sources strive to minimize the barrier to electron emission by engineering material properties (work function/electron affinity) or physical geometry (field enhancement) of the cathode. The unique capabilities of cold cathodes, such as instant ON/OFF performance, high brightness, high current density, large transconductance to capacitance ratio, cold emission, small size and/or low voltage operation characteristics, commend their use in several advanced devices when physical size, weight, power consumption, beam current, and pulse repletion frequency are important, e.g., RF power amplifier such as traveling wave tubes (TWTs) for radar and communications, electrodynamic tethers for satellite deboost/reboost, and electric propulsion systems such as Hall thrusters for small satellites. The theoretical program described herein is directed towards models to evaluate emission current from electron sources (in particular, emission from WBG and Spindt-type field emitter) in order to assess their utility, capabilities and performance characteristics. Modeling efforts particularly include: band bending, non-linear and resonant (Poole-Frenkel) potentials, the extension of one-dimensional theory to multi-dimensional structures, and emission site statistics due to variations in geometry and the presence of adsorbates. Two particular methodologies, namely, the modified Airy approach and metal-semiconductor statistical hyperbolic/ellipsoidal model, are described in detail in their present stage of development.

  5. On the application of quantum transport theory to electron sources.

    Science.gov (United States)

    Jensen, Kevin L

    2003-01-01

    Electron sources (e.g., field emitter arrays, wide band-gap (WBG) semiconductor materials and coatings, carbon nanotubes, etc.) seek to exploit ballistic transport within the vacuum after emission from microfabricated structures. Regardless of kind, all sources strive to minimize the barrier to electron emission by engineering material properties (work function/electron affinity) or physical geometry (field enhancement) of the cathode. The unique capabilities of cold cathodes, such as instant ON/OFF performance, high brightness, high current density, large transconductance to capacitance ratio, cold emission, small size and/or low voltage operation characteristics, commend their use in several advanced devices when physical size, weight, power consumption, beam current, and pulse repletion frequency are important, e.g., RF power amplifier such as traveling wave tubes (TWTs) for radar and communications, electrodynamic tethers for satellite deboost/reboost, and electric propulsion systems such as Hall thrusters for small satellites. The theoretical program described herein is directed towards models to evaluate emission current from electron sources (in particular, emission from WBG and Spindt-type field emitter) in order to assess their utility, capabilities and performance characteristics. Modeling efforts particularly include: band bending, non-linear and resonant (Poole-Frenkel) potentials, the extension of one-dimensional theory to multi-dimensional structures, and emission site statistics due to variations in geometry and the presence of adsorbates. Two particular methodologies, namely, the modified Airy approach and metal-semiconductor statistical hyperbolic/ellipsoidal model, are described in detail in their present stage of development.

  6. A midrapidity source of intermediate mass fragments in highly central collisions of Au+Au at 150 A MeV

    Energy Technology Data Exchange (ETDEWEB)

    Alard, J.P.; Bastid, N.; Crouau, M.; Dupieux, P.; Fraysse, L.; Jorio, M.; Montarou, G.; Morel, P. [Laboratoire de Physique Corpusculaire, 63 - Clermont-Ferrand (France); Basrak, Z.; Caplar, R.; Cindro, N.; Hoelbling, S. [Rudjer Boskovic Inst., Zagreb (Yugoslavia); Belayev, I.M.; Frolov, S.; Korchagin, Y.; Lebedev, A.; Smolyankin, S.; Zhilin, A.V. [Institute for Experimental and Theoretical Physics, Moscow (Russia); Bini, M.; Olmi, A.; Pasquali, G.; Poggi, G.; Taccetti, N. [Florence Univ. (Italy)]|[INFN, Florence (Italy); Blaich, T. [Mainz Univ. (Germany); Buta, A.; Legrand, I.; Moisa, D.; Petrovici, M.; Simion, V. [Institute for Physics and Nuclear Engineering, Bucharest (Romania); Cerruti, C.; Coffin, J.P.; Fintz, P.; Guillaume, G.; Houari, O.; Jundt, F.; Kuhn, C.; Maguire, C.; Rami, F.; Tezkratt, R.; Wagner, P. [Centre de Recherches Nucleaires, 67 - Strasbourg (France)]|[Strasbourg Univ., 67 (France); Eroe, J.; Fodor, Z.; Kecskemeti, J.; Koncz, P.; Seres, Z. [Central Research Inst. for Physics, Budapest (Hungary); Grigoriyan, Y.; Manko, V.; Mgebrishvili, G.; Sadchikov, A.; Vasiliev, M.A. [Kurchatov Inst. for Atomic Energy, Moscow (Russia); Herrmann, N.; Pelte, D.; Trzaska, M.; Wienold, T. [Heidelberg Univ. (Germany). Physikalisches Inst.; Kotte, R.; Moesner, J.; Neubert, W.; Wohlfarth, D. [Forschungszentrum Rossendorf (Germany); Matulewicz, T.; Sikora, B.; Wilhelmi, Z. [Warsaw Univ. (Poland). Inst. of Experimental Physics; Bock, R.; Fan, Z.G.; Freifelder, R.; Gobbi, A.; Hildenbrand, K.D.; Jeong, S.C.; Kraemer, M.; Reisdorf, W.; Schuell, D.; Sodan, U.; Teh, K.; Wessels, J.P.; FOPI Collaboration at GSI

    1992-02-01

    Charged particles have been observed in collisions of Au on Au at incident energy of 150 A MeV using a high-granularity detector system covering approximatley the forward hemisphere in the center-of-mass system. Highly central collisions have been studied using a double selection criterion which combines large charged particle multiplicities with small transverse momentum directivities. In this class of events about one quarter of the total nuclear charge emerges as intermediate mass fragments with nuclear charges Z>2. These fragments are centred at midrapidity and are produced with large transverse velocities. (orig.).

  7. Holmium-161 produced using 11.6 MeV protons: A practical source of narrow-band X-rays

    Energy Technology Data Exchange (ETDEWEB)

    Stephens, Bryan J., E-mail: bryan.j.stephens@vanderbilt.ed [Department of Physics, Vanderbilt University, 6301 Stevenson Center, P.O. Box 351807 Station B, Nashville, TN 37235 (United States); Mendenhall, Marcus H., E-mail: marcus.h.mendenhall@vanderbilt.ed [Department of Electrical Engineering, Vandberbilt University, P.O. Box 351824 Station B, Nashville, TN 37235-1824 (United States)

    2010-10-15

    We present a novel technique to produce narrow-band X-rays by preparing {sup 161}Ho from the bombardment of dysprosium foil by 11.6 MeV protons. The activated foil produces predominantly 45-55 keV X-rays, which are suitable for activating iodinated radio-sensitizing agents (e.g. IUdR) for oncological therapy. We demonstrate that clinically useful quantities of the nuclide are easily produced with a medical cyclotron which is far from the current state of the art.

  8. Compact Short-Pulsed Electron Linac Based Neutron Sources for Precise Nuclear Material Analysis

    Science.gov (United States)

    Uesaka, M.; Tagi, K.; Matsuyama, D.; Fujiwara, T.; Dobashi, K.; Yamamoto, M.; Harada, H.

    2015-10-01

    An X-band (11.424GHz) electron linac as a neutron source for nuclear data study for the melted fuel debris analysis and nuclear security in Fukushima is under development. Originally we developed the linac for Compton scattering X-ray source. Quantitative material analysis and forensics for nuclear security will start several years later after the safe settlement of the accident is established. For the purpose, we should now accumulate more precise nuclear data of U, Pu, etc., especially in epithermal (0.1-10 eV) neutrons. Therefore, we have decided to modify and install the linac in the core space of the experimental nuclear reactor "Yayoi" which is now under the decommission procedure. Due to the compactness of the X-band linac, an electron gun, accelerating tube and other components can be installed in a small space in the core. First we plan to perform the time-of-flight (TOF) transmission measurement for study of total cross sections of the nuclei for 0.1-10 eV energy neutrons. Therefore, if we adopt a TOF line of less than 10m, the o-pulse length of generated neutrons should be shorter than 100 ns. Electronenergy, o-pulse length, power, and neutron yield are ~30 MeV, 100 ns - 1 micros, ~0.4 kW, and ~1011 n/s (~103 n/cm2/s at samples), respectively. Optimization of the design of a neutron target (Ta, W, 238U), TOF line and neutron detector (Ce:LiCAF) of high sensitivity and fast response is underway. We are upgrading the electron gun and a buncher to realize higher current and beam power with a reasonable beam size in order to avoid damage of the neutron target. Although the neutron flux is limited in case of the X-band electron linac based source, we take advantage of its short pulse aspect and availability for nuclear data measurement with a short TOF system. First, we form a tentative configuration in the current experimental room for Compton scattering in 2014. Then, after the decommissioning has been finished, we move it to the "Yayoi" room and perform

  9. Wind Power - A Power Source Enabled by Power Electronics

    DEFF Research Database (Denmark)

    Blaabjerg, Frede; Chen, Zhe

    2004-01-01

    The global electrical energy consumption is still rising and there is a steady demand to increase the power capacity. The production, distribution and the use of the energy should be as technological efficient as possible and incentives to save energy at the end-user should be set up. The deregul......The global electrical energy consumption is still rising and there is a steady demand to increase the power capacity. The production, distribution and the use of the energy should be as technological efficient as possible and incentives to save energy at the end-user should be set up....... The deregulation of energy has lowered the investment in bigger power plants, which means the need for new electrical power sources may be very high in the near future. Two major technologies will play important roles to solve the future problems. One is to change the electrical power production sources from...... the conventional, fossil (and short term) based energy sources to renewable energy sources. The other is to use high efficient power electronics in power systems, power production and end-user application. This paper discuss the most emerging renewable energy source, wind energy, which by means of power...

  10. Reductive dechlorination of trichloroethene DNAPL source zones: source zone architecture versus electron donor availability

    Science.gov (United States)

    Krol, M.; Kokkinaki, A.; Sleep, B.

    2014-12-01

    The persistence of dense-non-aqueous-phase liquids (DNAPLs) in the subsurface has led practitioners and regulatory agencies to turn towards low-maintenance, low-cost remediation methods. Biological degradation has been suggested as a possible solution, based on the well-proven ability of certain microbial species to break down dissolved chlorinated ethenes under favorable conditions. However, the biodegradation of pure phase chlorinated ethenes is subject to additional constraints: the continuous release of electron acceptor at a rate governed by mass transfer kinetics, and the temporal and spatial heterogeneity of DNAPL source zones which leads to spatially and temporally variable availability of the reactants for reductive dechlorination. In this work, we investigate the relationship between various DNAPL source zone characteristics and reaction kinetics using COMPSIM, a multiphase groundwater model that considers non-equilibrium mass transfer and Monod-type kinetics for reductive dechlorination. Numerical simulations are performed for simple, homogeneous trichloroethene DNAPL source zones to demonstrate the effect of single source zone characteristics, as well as for larger, more realistic heterogeneous source zones. It is shown that source zone size, and mass transfer kinetics may have a decisive effect on the predicted bio-enhancement. Finally, we evaluate the performance of DNAPL bioremediation for realistic, thermodynamically constrained, concentrations of electron donor. Our results indicate that the latter may be the most important limitation for the success of DNAPL bioremediation, leading to reduced bio-enhancement and, in many cases, comparable performance with water flooding.

  11. Generation and application of pseudospark-sourced electron beams

    Energy Technology Data Exchange (ETDEWEB)

    Cross, A W [SUPA, Department of Physics, University of Strathclyde, Glasgow G4 0NG (United Kingdom); Yin, H [SUPA, Department of Physics, University of Strathclyde, Glasgow G4 0NG (United Kingdom); He, W [SUPA, Department of Physics, University of Strathclyde, Glasgow G4 0NG (United Kingdom); Ronald, K [SUPA, Department of Physics, University of Strathclyde, Glasgow G4 0NG (United Kingdom); Phelps, A D R [SUPA, Department of Physics, University of Strathclyde, Glasgow G4 0NG (United Kingdom); Pitchford, L C [CAPT, Universite Paul Sabatier, 118 rte de Narbonne, 31062 Toulouse (France)

    2007-04-07

    A pseudospark (PS) discharge has been shown to be a promising source of high brightness, high intensity electron beam pulses. A PS-sourced electron beam has two phases, an initial hollow cathode phase (HCP) beam followed by a conductive phase (CP) beam. In our experiments, a 22 kV, 50 A HCP beam of brightness 10{sup 9-10} A m{sup -2} rad{sup -2} followed by a 200 V, 200 A CP beam of brightness 10{sup 11-12} A m{sup -2} rad{sup -2} were measured. Experiments have been conducted with the application of a HCP beam in a Cherenkov interaction with no input seed wave and with post-acceleration of the CP beam. In this paper, a new Cherenkov interaction experiment with an input seed wave from a 20 kW, 35 GHz pulsed magnetron has been designed using the same PS HCP beam. Simulation results of the interaction will be presented and further PS electron beam applications will be discussed.

  12. Extraction of ions and electrons from audio frequency plasma source

    Directory of Open Access Journals (Sweden)

    N. A. Haleem

    2016-09-01

    Full Text Available Herein, the extraction of high ion / electron current from an audio frequency (AF nitrogen gas discharge (10 – 100 kHz is studied and investigated. This system is featured by its small size (L= 20 cm and inner diameter = 3.4 cm and its capacitive discharge electrodes inside the tube and its high discharge pressure ∼ 0.3 Torr, without the need of high vacuum system or magnetic fields. The extraction system of ion/electron current from the plasma is a very simple electrode that allows self-beam focusing by adjusting its position from the source exit. The working discharge conditions were applied at a frequency from 10 to 100 kHz, power from 50 – 500 W and the gap distance between the plasma meniscus surface and the extractor electrode extending from 3 to 13 mm. The extracted ion/ electron current is found mainly dependent on the discharge power, the extraction gap width and the frequency of the audio supply. SIMION 3D program version 7.0 package is used to generate a simulation of ion trajectories as a reference to compare and to optimize the experimental extraction beam from the present audio frequency plasma source using identical operational conditions. The focal point as well the beam diameter at the collector area is deduced. The simulations showed a respectable agreement with the experimental results all together provide the optimizing basis of the extraction electrode construction and its parameters for beam production.

  13. Multi-port power electronic interface for renewable energy sources

    Science.gov (United States)

    Jiang, Wei

    Energy intensive products and services are penetrating people's daily life as well as different sectors of industry during recent decades. Further effort to improve efficiency, reduce green house gas and hazardous particle emission lead to the emergence of the "more electric" concept in several industries including transportation. This trend, however, burdens the aging power system and existing local power networks. To offer a remedy to the problem and a smooth transition to a more reliable, more diverse, and more efficient power grid of the future, the concept of Multi-port Power Electronic Interface (MPEI) for localized power processing is introduced in this dissertation, which interfaces and manages various sources, loads and storages. Different means of integrating multiple sources and storages into the existing power system are studied and evaluated; the six phase-leg structure is chosen to interface five sources/loads: fuel cell, wind turbine, solar cell, battery and utility grid. Partitioning of source-interface and load-interface on a system level as well as analysis and modeling on small signal level are performed. A novel control structure for source-interface is proposed in the design, which forms Controlled Quasi Current Source (CQCS) during the load sharing operation and offers several salient advantages: • Inherent average current-mode control. • Easy share of steady state current/power. • Share of load dynamics for better source protection. Local control loops for various input ports are designed based on linearized system model; controller performance is tuned to accommodate the characteristics of different sources. To maintain a sustainable operation, different modes of operation are defined for MPEI; detailed state-transition with associated events are also defined in each operation mode. Prototype of MPEI is built and control system is implemented digitally in a digital signal processor; steady state and transient performance of MPEI is

  14. ATLAS 10 GHz electron cyclotron resonance ion source upgrade project

    Energy Technology Data Exchange (ETDEWEB)

    Moehs, D. P. [Argonne National Laboratory, Physics Division, Argonne, Illinois 60439 (United States); Vondrasek, R. [Argonne National Laboratory, Physics Division, Argonne, Illinois 60439 (United States); Pardo, R. C. [Argonne National Laboratory, Physics Division, Argonne, Illinois 60439 (United States); Xie, D. [Berkeley Ion Equipment Inc., Santa Clara, California 95054 (United States)

    2000-02-01

    A major upgrade of the first ATLAS 10 GHz electron cyclotron resonance (ECR) ion source, which began operations in 1987, is in the planning and procurement phase. The new design will convert the old two-stage source into a single-stage source with an electron donor disk and high gradient magnetic field that preserves radial access for solid material feeds and pumping of the plasma chamber. The new magnetic-field profile allows for the possibility of a second ECR zone at a frequency of 14 GHz. An open hexapole configuration, using a high-energy-product Nd-Fe-B magnet material, having an inner diameter of 8.8 cm and pole gaps of 2.4 cm, has been adopted. Models indicate that the field strengths at the chamber wall, 4 cm in radius, will be 9.3 kG along the magnet poles and 5.6 kG along the pole gaps. The individual magnet bars will be housed in austenitic stainless steel, allowing the magnet housing within the aluminum plasma chamber to be used as a water channel for direct cooling of the magnets. Eight solenoid coils from the existing ECR will be enclosed in an iron yoke to produce the axial mirror. Based on a current of 500 A, the final model predicts a minimum B field of 3 kG with injection and extraction mirror ratios of 4.4 and 2.9, respectively. (c) 2000 American Institute of Physics.

  15. ATLAS 10 GHz electron cyclotron resonance ion source upgrade project

    CERN Document Server

    Moehs, D P; Pardo, R C; Xie, D

    2000-01-01

    A major upgrade of the first ATLAS 10 GHz electron cyclotron resonance (ECR) ion source, which began operations in 1987, is in the planning and procurement phase. The new design will convert the old two-stage source into a single-stage source with an electron donor disk and high gradient magnetic field that preserves radial access for solid material feeds and pumping of the plasma chamber. The new magnetic-field profile allows for the possibility of a second ECR zone at a frequency of 14 GHz. An open hexapole configuration, using a high-energy-product Nd-Fe-B magnet material, having an inner diameter of 8.8 cm and pole gaps of 2.4 cm, has been adopted. Models indicate that the field strengths at the chamber wall, 4 cm in radius, will be 9.3 kG along the magnet poles and 5.6 kG along the pole gaps. The individual magnet bars will be housed in austenitic stainless steel, allowing the magnet housing within the aluminum plasma chamber to be used as a water channel for direct cooling of the magnets. Eight solenoid...

  16. Fabrication of nano ion–electron sources and nano-probes by local electron bombardment

    Energy Technology Data Exchange (ETDEWEB)

    Rezeq, Moh’d, E-mail: mohd.rezeq@kustar.ac.ae [Department of Applied Mathematics and Sciences, Khalifa University of Science, Technology and Research (KUSTAR), P.O.B. 127788, Abu Dhabi (United Arab Emirates); Department of Electrical and Computer Engineering, Khalifa University of Science, Technology and Research (KUSTAR), P.O.B. 127788, Abu Dhabi (United Arab Emirates); Ali, Ahmed; Barada, Hassan [Department of Electrical and Computer Engineering, Khalifa University of Science, Technology and Research (KUSTAR), P.O.B. 127788, Abu Dhabi (United Arab Emirates)

    2015-04-01

    Highlights: • A new method for fabricating nanotips with an apex radius around 1 nm is introduced. • This clean process depends only on the physical electron bombardment mechanism. • This method can be applied to any metal or heavily doped semiconductor materials. • The produced single atom nanotips are ideal as sources of electron and ion beams. • These nanotips are advantageous for nano lithography and scanning probe microscopy. - Abstract: A new method for fabricating nano ion–electron sources and nano probes with an apex in the range of 1 nm is introduced. The method is based on bombarding a regular tip apex with electrons extracted and accelerated from a nearby source by the electric field. This can be achieved by placing a metal ring around a precursor metal tip at a level below the tip apex in a field ion microscope (FIM). The metal ring is then heated, by a grounded DC power source, to a temperature below the thermionic emission value. The electric field between the tip and the hot ring is high enough to cause electrons to be extracted from the metal ring, i.e. Schottky field emission, and then accelerated to the shank with energy sufficient to dislodge atoms from the shank. An atomic scale apex with a single atom end can be obtained by monitoring the evolution of the tip apex due to the movement of mobile atoms while adjusting the tip electric field and the temperature of the metal ring. As this method depends only on the electron bombardment mechanism, this makes it a clean process that can be applied to any metal or heavily doped semiconductor materials appropriate for generating a high electric field for FIM applications.

  17. Electron Beam Diagnostics at the Radiation Source ELBE

    Science.gov (United States)

    Evtushenko, P.; Lehnert, U.; Michel, P.; Schneider, C.; Schurig, R.; Teichert, J.

    2002-12-01

    In the research center Rossendorf, the radiation source ELBE, based on a super conducting LINAC, is under construction. In the year 2001 the first accelerating module was commissioned. The electron beam parameters like emittance, bunch length, energy spread were measured. Here we present results of the measurements as well as the methods used to make the measurements. In the ELBE injector, where electron beam energy is 250 keV, the emittance was measured with the aid of a multislit device. Emittance of the accelerated beam was measured by means of quadrupole scan method and is 8 mm×mrad at 77 pC bunch charge. Electron bunch length was measured using the coherent transition radiation technique. At the maximum design bunch charge of 77 pC the RMS bunch length was measured to be 2 ps. A set of online diagnostic systems is also under development. One these include a system of stripline beam position monitors is also described here. A BPM resolution of about 10 μm was achieved using logarithmic amplifier as the core element of the BPM electronics. A system of beam loss monitors based on the RF Heliax cable working as an ionization chamber is intended to be another online diagnostic system.

  18. Note: Simulation and test of a strip source electron gun

    Science.gov (United States)

    Iqbal, Munawar; Islam, G. U.; Misbah, I.; Iqbal, O.; Zhou, Z.

    2014-06-01

    We present simulation and test of an indirectly heated strip source electron beam gun assembly using Stanford Linear Accelerator Center (SLAC) electron beam trajectory program. The beam is now sharply focused with 3.04 mm diameter in the post anode region at 15.9 mm. The measured emission current and emission density were 1.12 A and 1.15 A/cm2, respectively, that corresponds to power density of 11.5 kW/cm2, at 10 kV acceleration potential. The simulated results were compared with then and now experiments and found in agreement. The gun is without any biasing, electrostatic and magnetic fields; hence simple and inexpensive. Moreover, it is now more powerful and is useful for accelerators technology due to high emission and low emittance parameters.

  19. Microlens Array Laser Transverse Shaping Technique for Photoemission Electron Source

    CERN Document Server

    Halavanau, A; Qiang, G; Gai, W; Power, J; Piot, P; Wisniewski, E; Edstrom, D; Ruan, J; Santucci, J

    2016-01-01

    A common issue encountered in photoemission electron sources used in electron accelerators is distortion of the laser spot due to non ideal conditions at all stages of the amplification. Such a laser spot at the cathode may produce asymmetric charged beams that will result in degradation of the beam quality due to space charge at early stages of acceleration and fail to optimally utilize the cathode surface. In this note we study the possibility of using microlens arrays to dramatically improve the transverse uniformity of the drive laser pulse on UV photocathodes at both Fermilab Accelerator Science \\& Technology (FAST) facility and Argonne Wakefield Accelerator (AWA). In particular, we discuss the experimental characterization of the homogeneity and periodic patterned formation at the photocathode. Finally, we compare the experimental results with the paraxial analysis, ray tracing and wavefront propagation software.

  20. Towards Evidence-Based Understanding of Electronic Data Sources

    DEFF Research Database (Denmark)

    Chen, Lianping; Ali Babar, Muhammad; Zhang, He

    2010-01-01

    Identifying relevant papers from various Electronic Data Sources (EDS) is one of the key activities of conducting these kinds of studies. Hence, the selection of EDS for searching the potentially relevant papers is an important decision, which can affect a study’s coverage of relevant papers....... Researchers usually select EDS mainly based on personal knowledge, experience, and preferences and/or recommendations by other researchers. We believe that building an evidence-based understanding of EDS can enable researchers to make more informed decisions about the selection of EDS. This paper reports our...

  1. A Flexible Power Electronics Configuration for Coupling Renewable Energy Sources

    Directory of Open Access Journals (Sweden)

    Mattia Filippini

    2015-05-01

    Full Text Available A combination of series, parallel and multilevel power electronics has been investigated as a potential interface for two different types of renewable energy sources and in order to reach higher power levels. Renewable energy sources are typically dispersed in a territory, and sources, like wind and solar, allow small to medium-scale generation of electricity. The configuration investigated in this article aims at adapting the coupling solution to the specific generation characteristics of the renewable energy source to make it fit the electrical network. The configuration consists of a combination of three-phase multilevel converters and single-phase inverters, which are designed to provide flexibility, high power quality and high efficiency. A detailed analysis and simulation is performed to identify the properties in conjunction with the electrical grid requirements and the potential challenges encountered during operation. An optimized operation example of wind generation combined with solar PV generation is presented to exemplify the flexibility and benefits of the proposed configuration.

  2. Characterization of 2 MeV, 4 MeV, 6 MeV and 18 MeV buildup caps for use with a 0.6 cubic centimeter thimble ionization chamber

    Energy Technology Data Exchange (ETDEWEB)

    Salyer, R.L.; VanDenburg, J.W.; Prinja, A.K.; Kirby, T.; Busch, R. [Univ. of New Mexico, Albuquerque, NM (United States); Hong-Nian Jow [Sandia National Laboratories, Albuquerque, NM (United States)

    1996-07-01

    The purpose of this research is to characterize existing 2 MeV, 4 MeV and 6 MeV buildup caps, and to determine if a buildup cap can be made for the 0.6 cm{sup 3} thimble ionization chamber that will accurately measure exposures in a high-energy photon radiation field. Two different radiation transport codes were used to computationally characterize existing 2 MeV, 4 MeV, and 6 MeV buildup caps for a 0.6 cm{sup 3} active volume thimble ionization chamber: ITS, The Integrated TIGER Series of Coupled Electron-Photon Monte Carlo Transport Codes; and CEPXS/ONEDANT, A One-Dimensional Coupled Electron-Photon Discrete Ordinates Code Package. These codes were also used to determine the design characteristics of a buildup cap for use in the 18 MeV photon beam produced by the 14 TW pulsed power HERMES-III electron accelerator. The maximum range of the secondary electron, the depth at which maximum dose occurs, and the point where dose and collision kerma are equal have been determined to establish the validity of electronic equilibrium. The ionization chamber with the appropriate buildup cap was then subjected to a 4 MeV and a 6 MeV bremmstrahlung radiation spectrum to determine the detector response.

  3. Liquid metal ion source assembly for external ion injection into an electron string ion source (ESIS)

    Energy Technology Data Exchange (ETDEWEB)

    Segal, M. J., E-mail: mattiti@gmail.com [iThemba LABS, P.O. Box 722, Somerset West 7130 (South Africa); University of Cape Town, Rondebosch, Cape Town 7700 (South Africa); Bark, R. A.; Thomae, R. [iThemba LABS, P.O. Box 722, Somerset West 7130 (South Africa); Donets, E. E.; Donets, E. D.; Boytsov, A.; Ponkin, D.; Ramsdorf, A. [Joint Institute for Nuclear Research, Joloit-Curie 6, 141980 Dubna, Moscow Region (Russian Federation)

    2016-02-15

    An assembly for a commercial Ga{sup +} liquid metal ion source in combination with an ion transportation and focusing system, a pulse high-voltage quadrupole deflector, and a beam diagnostics system has been constructed in the framework of the iThemba LABS (Cape Town, South Africa)—JINR (Dubna, Russia) collaboration. First, results on Ga{sup +} ion beam commissioning will be presented. Outlook of further experiments for measurements of charge breeding efficiency in the electron string ion source with the use of external injection of Ga{sup +} and Au{sup +} ion beams will be reported as well.

  4. First test of BNL electron beam ion source with high current density electron beam

    Energy Technology Data Exchange (ETDEWEB)

    Pikin, Alexander, E-mail: pikin@bnl.gov; Alessi, James G., E-mail: pikin@bnl.gov; Beebe, Edward N., E-mail: pikin@bnl.gov [Brookhaven National Laboratory, Upton, NY 11973 (United States); Shornikov, Andrey; Mertzig, Robert; Wenander, Fredrik; Scrivens, Richard [CERN, CH-1211 Geneva 23 (Switzerland)

    2015-01-09

    A new electron gun with electrostatic compression has been installed at the Electron Beam Ion Source (EBIS) Test Stand at BNL. This is a collaborative effort by BNL and CERN teams with a common goal to study an EBIS with electron beam current up to 10 A, current density up to 10,000 A/cm{sup 2} and energy more than 50 keV. Intensive and pure beams of heavy highly charged ions with mass-to-charge ratio < 4.5 are requested by many heavy ion research facilities including NASA Space Radiation Laboratory (NSRL) at BNL and HIE-ISOLDE at CERN. With a multiampere electron gun, the EBIS should be capable of delivering highly charged ions for both RHIC facility applications at BNL and for ISOLDE experiments at CERN. Details of the electron gun simulations and design, and the Test EBIS electrostatic and magnetostatic structures with the new electron gun are presented. The experimental results of the electron beam transmission are given.

  5. Development of a coherent THz radiation source based on the ultra-short electron beam and its applications

    Science.gov (United States)

    Kuroda, R.; Yasumoto, M.; Toyokawa, H.; Sei, N.; Koike, M.; Yamada, K.

    2011-05-01

    At the National Institute of Advanced Industrial Science and Technology (AIST), a coherent terahertz (THz) radiation source has been developed based on an ultra-short electron beam using an S-band compact electron linac. The designed THz pulse has a high peak power of more than 1 kW in the frequency range 0.1-2 THz. The entire system is located in one research room of about 10 m square. The linac consists of a laser photocathode rf gun (BNL type) with a Cs2Te photocathode load-lock system and two 1.5-m-long S-band accelerator tubes. The electron beam can be accelerated up to approximately 42 MeV. The electron bunch was compressed to less than 1 ps (rms) with a magnetic bunch compressor. The coherent synchrotron radiation (CSR) of the THz region was generated from the ultra-short electron bunch at the 90° bending magnet, and it was extracted from a z-cut quartz window for THz applications. In this work, the THz scanning transmission imaging was successfully demonstrated for measuring the freshness of a vegetable leaf over a period of time.

  6. 77 FR 76049 - Draft Guidance for Industry on Electronic Source Data in Clinical Investigations; Correction

    Science.gov (United States)

    2012-12-26

    ... guidance entitled ``Electronic Source Data in Clinical Investigations.'' The document was published with an... HUMAN SERVICES Food and Drug Administration Draft Guidance for Industry on Electronic Source Data in Clinical Investigations; Correction AGENCY: Food and Drug Administration, HHS. ACTION: Notice;...

  7. Dosimetry of the energy of the electrons beam and virtual distance of the source of a lineal accelerator; Dosimetria de la energia del haz de electrones y distancia virtual de la fuente de un acelerador lineal

    Energy Technology Data Exchange (ETDEWEB)

    Gonzales, A.; Garcia, B.; Ramirez, J.; Marquina, J., E-mail: andres.gonzales@aliada.com.pe [ALIADA, Oncologia Integral, Av. Jose Galvez Barrenechea 1044, San Isidro, Lima 27 (Peru)

    2014-08-15

    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{sub 50.ion} = 4, 95 g/cm{sup 2}, R{sub 50} = 5, 04 g/cm{sup 2}, Z{sub ref} = 2,92 g/cm{sup 2}, Z{sub max} = 2, 60 g/cm{sup 2}. In the calibration was found D{sub W,Q}(Z{sub 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)

  8. Annual Cosmic Ray Spectra from 250 MeV up to 1.6 GeV from 1995 - 2014 Measured With the Electron Proton Helium Instrument onboard SOHO

    CERN Document Server

    Kühl, P; Heber, B

    2016-01-01

    The solar modulation of galactic cosmic rays (GCR) can be studied in detail by examining long-term variations of the GCR energy spectrum (e.g. on the scales of a solar cycle). With almost 20 years of data, the Electron Proton Helium INstrument (EPHIN) onboard the SOlar and Heliospheric Observatory (SOHO) is well suited for this kind of investigation. Although the design of the instrument is optimized to measure proton and helium isotope spectra up to 50 MeV nucleon$^{-1}$ , the capability exists to determine proton energy spectra from 250 MeV up to above 1.6 GeV. Therefore we developed a sophisticated inversion method to calculate such proton spectra. The method relies on a GEANT4 Monte Carlo simulation of the instrument and a simplified spacecraft model that calculates the energy-response function of EPHIN for electrons, protons and heavier ions. For validation purposes, proton spectra based on this method are compared to various balloon missions and space instrumentation. As a result we present annual galac...

  9. Resolution enhancement in transmission electron microscopy with 60-kV monochromated electron source

    Energy Technology Data Exchange (ETDEWEB)

    Morishita, Shigeyuki; Mukai, Masaki; Sawada, Hidetaka [JEOL Ltd., 3-1-2 Musashino, Akishima, Tokyo 196-8558 (Japan); Suenaga, Kazutomo [National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565 (Japan)

    2016-01-04

    Transmission electron microscopy (TEM) at low accelerating voltages is useful to obtain images with low irradiation damage. For a low accelerating voltage, linear information transfer, which determines the resolution for observation of single-layered materials, is largely limited by defocus spread, which improves when a narrow energy spread is used in the electron source. In this study, we have evaluated the resolution of images obtained at 60 kV by TEM performed with a monochromated electron source. The defocus spread has been evaluated by comparing diffractogram tableaux from TEM images obtained under nonmonochromated and monochromated illumination. The information limits for different energy spreads were precisely measured by using diffractograms with a large beam tilt. The result shows that the information limit reaches 0.1 nm with an energy width of 0.10 eV. With this monochromated source and a higher-order aberration corrector, we have obtained images of single carbon atoms in a graphene sheet by TEM at 60 kV.

  10. The cardiac implantable electronic device power source: evolution and revolution.

    Science.gov (United States)

    Mond, Harry G; Freitag, Gary

    2014-12-01

    Although the first power source for an implantable pacemaker was a rechargeable nickel-cadmium battery, it was rapidly replaced by an unreliable short-life zinc-mercury cell. This sustained the small pacemaker industry until the early 1970s, when the lithium-iodine cell became the dominant power source for low voltage, microampere current, single- and dual-chamber pacemakers. By the early 2000s, a number of significant advances were occurring with pacemaker technology which necessitated that the power source should now provide milliampere current for data logging, telemetric communication, and programming, as well as powering more complicated pacing devices such as biventricular pacemakers, treatment or prevention of atrial tachyarrhythmias, and the integration of innovative physiologic sensors. Because the current delivery of the lithium-iodine battery was inadequate for these functions, other lithium anode chemistries that can provide medium power were introduced. These include lithium-carbon monofluoride, lithium-manganese dioxide, and lithium-silver vanadium oxide/carbon mono-fluoride hybrids. In the early 1980s, the first implantable defibrillators for high voltage therapy used a lithium-vanadium pentoxide battery. With the introduction of the implantable cardioverter defibrillator, the reliable lithium-silver vanadium oxide became the power source. More recently, because of the demands of biventricular pacing, data logging, and telemetry, lithium-manganese dioxide and the hybrid lithium-silver vanadium oxide/carbon mono-fluoride laminate have also been used. Today all cardiac implantable electronic devices are powered by lithium anode batteries. ©2014 Wiley Periodicals, Inc.

  11. Use assessment of electronic power sources for SMAW

    Directory of Open Access Journals (Sweden)

    Scotti, A.

    1999-04-01

    Full Text Available The aim of the present work was to assess the efficacy of the use of modern technologies for power supplies in Shielded Metal Are Welding (SMAW. Coupon tests were welded by using a series of five different classes of commercial electrodes, covering their current ranges. Both a conventional electromagnetic and an electronic (inverter power sources were employed. Fusion rate, deposition efficiency, bead finish and weld geometry were measured at each experiment. Current and voltage signals were acquired at a high rate to evaluate the dynamic behavior of the power sources. The static performances of both power sources were also determined. The results showed that despite the remarkable differences between the power supplies, based on static and dynamic characterizations, no significant difference was noticed in the operational behavior of the electrodes, in the given conditions, apart from a better anti-stick performance obtained with the electronic power source.

    El objetivo del presente trabajo fue evaluar la eficacia del uso de tecnologías modernas para fuentes de energía en soldaduras con electrodo revestido (Shielded Metal Are Welding -SMAW-. Los materiales de ensayo se soldaron usando una serie de cinco clases diferentes de electrodos comerciales, cubriendo sus rangos de corriente. Para esto se utilizó una fuente de energía electromagnética convencional y una fuente de energía electrónica (inversora. La tasa de fusión, eficiencia de deposición, terminación del cordón así como el diseño de la soldadura se midieron en cada experimento. Las señales de corriente y voltaje se obtuvieron a una proporción alta para evaluar el comportamiento dinámico de las fuentes de energía. También se determinó la actuación estática de ambas fuentes. Los resultados mostraron que a pesar de las diferencias notables entre los suministros de energía, no se nota diferencia alguna significante en la conducta de trabajo de los electrodos, en

  12. Flexible and stretchable power sources for wearable electronics.

    Science.gov (United States)

    Zamarayeva, Alla M; Ostfeld, Aminy E; Wang, Michael; Duey, Jerica K; Deckman, Igal; Lechêne, Balthazar P; Davies, Greg; Steingart, Daniel A; Arias, Ana Claudia

    2017-06-01

    Flexible and stretchable power sources represent a key technology for the realization of wearable electronics. Developing flexible and stretchable batteries with mechanical endurance that is on par with commercial standards and offer compliance while retaining safety remains a significant challenge. We present a unique approach that demonstrates mechanically robust, intrinsically safe silver-zinc batteries. This approach uses current collectors with enhanced mechanical design, such as helical springs and serpentines, as a structural support and backbone for all battery components. We show wire-shaped batteries based on helical band springs that are resilient to fatigue and retain electrochemical performance over 17,000 flexure cycles at a 0.5-cm bending radius. Serpentine-shaped batteries can be stretched with tunable degree and directionality while maintaining their specific capacity. Finally, the batteries are integrated, as a wearable device, with a photovoltaic module that enables recharging of the batteries.

  13. Open source cardiology electronic health record development for DIGICARDIAC implementation

    Science.gov (United States)

    Dugarte, Nelson; Medina, Rubén.; Huiracocha, Lourdes; Rojas, Rubén.

    2015-12-01

    This article presents the development of a Cardiology Electronic Health Record (CEHR) system. Software consists of a structured algorithm designed under Health Level-7 (HL7) international standards. Novelty of the system is the integration of high resolution ECG (HRECG) signal acquisition and processing tools, patient information management tools and telecardiology tools. Acquisition tools are for management and control of the DIGICARDIAC electrocardiograph functions. Processing tools allow management of HRECG signal analysis searching for indicative patterns of cardiovascular pathologies. Telecardiology tools incorporation allows system communication with other health care centers decreasing access time to the patient information. CEHR system was completely developed using open source software. Preliminary results of process validation showed the system efficiency.

  14. Fast pulsed operation of a small non-radioactive electron source with continuous emission current control.

    Science.gov (United States)

    Cochems, P; Kirk, A T; Bunert, E; Runge, M; Goncalves, P; Zimmermann, S

    2015-06-01

    Non-radioactive electron sources are of great interest in any application requiring the emission of electrons at atmospheric pressure, as they offer better control over emission parameters than radioactive electron sources and are not subject to legal restrictions. Recently, we published a simple electron source consisting only of a vacuum housing, a filament, and a single control grid. In this paper, we present improved control electronics that utilize this control grid in order to focus and defocus the electron beam, thus pulsing the electron emission at atmospheric pressure. This allows short emission pulses and excellent stability of the emitted electron current due to continuous control, both during pulsed and continuous operations. As an application example, this electron source is coupled to an ion mobility spectrometer. Here, the pulsed electron source allows experiments on gas phase ion chemistry (e.g., ion generation and recombination kinetics) and can even remove the need for a traditional ion shutter.

  15. ELECTRON BEAM ION SOURCE PREINJECTOR PROJECT (EBIS) CONCEPTUAL DESIGN REPORT.

    Energy Technology Data Exchange (ETDEWEB)

    ALESSI, J.; BARTON, D.; BEEBE, E.; GASSNER, D.; ET AL.

    2005-02-28

    This report describes a new heavy ion pre-injector for the Relativistic Heavy Ion Collider (RHIC) based on a high charge state Electron Beam Ion Source (EBIS), a Radio Frequency Quadrupole (RFQ) accelerator, and a short Linac. The highly successful development of an EBIS at BNL now makes it possible to replace the present pre-injector that is based on an electrostatic Tandem with a reliable, low maintenance Linac-based pre-injector. Linac-based pre-injectors are presently used at most accelerator and collider facilities with the exception of RHIC, where the required gold beam intensities could only be met with a Tandem until the recent EBIS development. EBIS produces high charge state ions directly, eliminating the need for the two stripping foils presently used with the Tandem. Unstable stripping efficiencies of these foils are a significant source of luminosity degradation in RHIC. The high reliability and flexibility of the new Linac-based pre-injector will lead to increased integrated luminosity at RHIC and is an essential component for the long-term success of the RHIC facility. This new pre-injector, based on an EBIS, also has the potential for significant future intensity increases and can produce heavy ion beams of all species including uranium beams and, as part of a future upgrade, might also be used to produce polarized {sup 3}He beams. These capabilities will be critical to the future luminosity upgrades and electron-ion collisions in RHIC. The new RFQ and Linac that are used to accelerate beams from the EBIS to an energy sufficient for injection into the Booster are both very similar to existing devices already in operation at other facilities. Injection into the Booster will occur at the same location as the existing injection from the Tandem.

  16. Low energy electron point source microscopy: beyond imaging.

    Science.gov (United States)

    Beyer, André; Gölzhäuser, Armin

    2010-09-01

    Low energy electron point source (LEEPS) microscopy has the capability to record in-line holograms at very high magnifications with a fairly simple set-up. After the holograms are numerically reconstructed, structural features with the size of about 2 nm can be resolved. The achievement of an even higher resolution has been predicted. However, a number of obstacles are known to impede the realization of this goal, for example the presence of electric fields around the imaged object, electrostatic charging or radiation induced processes. This topical review gives an overview of the achievements as well as the difficulties in the efforts to shift the resolution limit of LEEPS microscopy towards the atomic level. A special emphasis is laid on the high sensitivity of low energy electrons to electrical fields, which limits the structural determination of the imaged objects. On the other hand, the investigation of the electrical field around objects of known structure is very useful for other tasks and LEEPS microscopy can be extended beyond the task of imaging. The determination of the electrical resistance of individual nanowires can be achieved by a proper analysis of the corresponding LEEPS micrographs. This conductivity imaging may be a very useful application for LEEPS microscopes.

  17. Chiral recognition in electron scattering by S- and R-2-butanol

    DEFF Research Database (Denmark)

    Jones, Nykola C.; Hoffmann, Søren Vrønning; Field, David

    2015-01-01

    Experiments are described involving the low energy scattering of electrons from the two optical enantiomers S- and R- 2-butanol. Using a synchrotron radiation photoionization source on the ASTRID storage ring, scattering spectra are reported between a few meV and 140 meV at an electron energy...

  18. Improvement of the tuneable monochromatic gamma-ray source at the 15 MeV linac of the University of Gent

    Science.gov (United States)

    Masschaele, B.; Jolie, J.; Mondelaers, W.; Materna, T.; Cauwels, P.; Dierick, M.

    2001-07-01

    It is shown how the tuneable gamma-ray source based on a bremsstrahlung source and a crystal, diffracting in Cauchois geometry, can be made intense and monochromatic using an asymmetrically cut Si crystal. The results and implications are here presented.

  19. Heavy Ion Injection Into Synchrotrons, Based On Electron String Ion Sources

    CERN Document Server

    Donets, E E; Syresin, E M

    2004-01-01

    A possibility of heavy ions injection into synchrotrons is discussed on the base of two novel ion sources, which are under development JINR during last decade: 1) the electron string ion source (ESIS), which is a modified version of a conventional electron beam ion source (EBIS), working in a reflex mode of operation, and 2) the tubular electron string ion source (TESIS). The Electron String Ion Source "Krion-2" (VBLHE, JINR, Dubna) with an applied confining magnetic field of 3 T was used for injection into the superconducting JINR synchrotron - Nuclotron and during this runs the source provided a high pulse intensity of the highly charged ion beams: Ar16+

  20. First H- beam accelerated at Linac4: 3MeV done, 157 MeV to go!

    CERN Multimedia

    Linac4 Project Team

    2013-01-01

    On 14 November, the first H- (one proton surrounded by two electrons) beam was accelerated to the energy of 3 MeV in the Linac4 - the new linear accelerator that will replace Linac2 as low-energy injector in the LHC accelerator chain.      A view of the Linac4 taken during the recent tests (top image) and the current measured by the instruments at the end of the acceleration line on 14 November (bottom image). Images: Linac4 collaboration. Using the recently installed Radio Frequency Quadrupole (RFQ) accelerator, 13 mA of current were accelerated to the energy of 3 MeV. After the successful commissioning of the Linac4 RFQ at the 3 MeV test stand completed during the first months of 2013, the whole equipment (composed of the RFQ itself, the following Medium Energy Beam Transport line and its diagnostic line) were moved to the Linac4 tunnel during summer and installed in their final position. In the meantime, a new ion source was assembled, installed and successfu...

  1. Effects of 6 MeV electron irradiation on the electrical properties and device parameters of Al/Al{sub 2}O{sub 3}/TiO{sub 2}/n-Si MOS capacitors

    Energy Technology Data Exchange (ETDEWEB)

    Laha, P.; Banerjee, I.; Barhai, P.K. [Department of Applied Physics, Birla Institute of Technology, Mesra, Ranchi 835215 (India); Das, A.K. [Laser and Plasma Technology Division, Bhabha Atomic Research Center, Mumbai 400085 (India); Bhoraskar, V.N. [Department of Physics, University of Pune, Ganeshkhind, Pune 411007 (India); Mahapatra, S.K., E-mail: skm@physics.ucla.edu [Department of Applied Physics, Birla Institute of Technology, Mesra, Ranchi 835215 (India)

    2012-07-15

    Highlights: Black-Right-Pointing-Pointer The electron irradiation effects make variation in the device parameters. Black-Right-Pointing-Pointer The device parameters changes due to percentage of defects and charge trapping. Black-Right-Pointing-Pointer Leakage current of Al/Al{sub 2}O{sub 3}/TiO{sub 2}/n-Si changes due to interface dangling bonds. Black-Right-Pointing-Pointer The leakage current mechanism of MOS structures is due to Poole-Frenkel effect. - Abstract: The effects of 6 MeV electron irradiation on the electrical properties and device parameter characteristics of Al/Al{sub 2}O{sub 3}/TiO{sub 2}/n-Si metal-oxide-semiconductor capacitors have been studied. Twelve Al/Al{sub 2}O{sub 3}/TiO{sub 2}/n-Si MOS capacitors were fabricated using r.f. magnetron sputtering and divided into four groups. The first group was not irradiated and treated as virgin. The rest were irradiated with 6 MeV electrons at doses 10, 20, and 30 kGy, maintaining the dose rate at {approx}1 kGy/min. Variations in crystallinity of the virgin and irradiated capacitors were studied using grazing incident X-ray diffraction. The thickness and in-depth elemental distributions of individual layers were determined using secondary ion mass apectrometry. Capacitance-voltage, conductance-voltage and leakage current-voltage characteristics of the virgin and irradiated samples were studied. The device parameters (flat band voltage, surface charge density and interface trap density of the virgin and irradiated structures) were determined. The electrical properties of the capacitors were investigated and the Poole-Frenkel coefficient of the capacitors was determined from leakage current measurements. The leakage current mechanism has been explained.

  2. Measurement of the lifetime of Pb$^{52+}$, Pb$^{53+}$ and Pb$^{54+}$ beams at 4.2 MeV per nucleon subject to electron cooling

    CERN Document Server

    Baird, S A; Carli, Christian; Chanel, M; Lefèvre, P; Ley, R; MacCaferri, R; Maury, S; Meshkov, I N; Möhl, D; Molinari, G; Motsch, F; Mulder, H; Tranquille, G; Varenne, F

    1995-01-01

    By measuring the lifetime of stored beams, the recombination of the ions with cooling electrons was investigated. Rates found are larger than expected for radiative electron capture and significantly higher for Pb53+ than for Pb54+ and Pb52+. These results are important for the design of the lead ion injection system for the Large Hadron Collider and for recombination theories.

  3. On the relationships between electron spot size, focal spot size, and virtual source position in Monte Carlo simulations

    Energy Technology Data Exchange (ETDEWEB)

    Sterpin, E.; Chen, Y.; Lu, W.; Mackie, T. R.; Olivera, G. H.; Vynckier, S. [Department of Molecular Imaging and Experimental Radiotherapy (IMRE), Universite Catholique de Louvain, 1200 Brussels (Belgium) and Department of Medical Physics, University of Wisconsin, Madison, Wisconsin 53705 (United States); TomoTherapy, Inc., Madison, Wisconsin 53717 (United States); Department of Medical Physics, University of Wisconsin, Madison, Wisconsin 53705 and TomoTherapy, Inc., Madison, Wisconsin 53717 (United States); TomoTherapy, Inc., Madison, Wisconsin 53717 (United States); Department of Molecular Imaging and Experimental Radiotherapy (IMRE), Universite Catholique de Louvain, 1200 Brussels (Belgium)

    2011-03-15

    Purpose: Every year, new radiotherapy techniques including stereotactic radiosurgery using linear accelerators give rise to new applications of Monte Carlo (MC) modeling. Accurate modeling requires knowing the size of the electron spot, one of the few parameters to tune in MC models. The resolution of integrated megavoltage imaging systems, such as the tomotherapy system, strongly depends on the photon spot size which is closely related to the electron spot. The aim of this article is to clarify the relationship between the electron spot size and the photon spot size (i.e., the focal spot size) for typical incident electron beam energies and target thicknesses. Methods: Three electron energies (3, 5.5, and 18 MeV), four electron spot sizes (FWHM=0, 0.5, 1, and 1.5 mm), and two tungsten target thicknesses (0.15 and 1 cm) were considered. The formation of the photon beam within the target was analyzed through electron energy deposition with depth, as well as photon production at several phase-space planes placed perpendicular to the beam axis, where only photons recorded for the first time were accounted for. Photon production was considered for ''newborn'' photons intersecting a 45x45 cm{sup 2} plane at the isocenter (85 cm from source). Finally, virtual source position and ''effective'' focal spot size were computed by backprojecting all the photons from the bottom of the target intersecting a 45x45 cm{sup 2} plane. The virtual source position and focal spot size were estimated at the plane position where the latter is minimal. Results: In the relevant case of considering only photons intersecting the 45x45 cm{sup 2} plane, the results unambiguously showed that the effective photon spot is created within the first 0.25 mm of the target and that electron and focal spots may be assumed to be equal within 3-4%. Conclusions: In a good approximation photon spot size equals electron spot size for high energy X-ray treatments

  4. Femtosecond electron diffraction. Next generation electron sources for atomically resolved dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Hirscht, Julian

    2015-08-15

    advantages of simplicity and stability of a compact FED apparatus with the short temporal resolution of femtosecond accelerators, which are operated with or include rf structures. Simulations of the electron beam dynamics and the fact that the apparatus is stable in respect to high voltages and electric field gradients above 27 MV/m allows the conclusion, that a temporal resolution significantly below 100 fs (fwhm), perhaps even shorter than 70 fs, can be achieved. This instrument currently defines the state-of-the-art. Firstly, because high voltage feedthrough for these potentials are commercially still not available, with a subsequent limiting of the potentials and consequent lowering of the electron numbers per pulse as well as the pulse durations and electron penetration. Secondly, this is because research communities focus on photon and rf-based electron sources for the achievement of sub-100 fs pulses, which typically include timing-jitter. Here it is shown that simple DC acceleration can lead to the same, satisfactory pulse duration up to an energy of a few hundred keV, potentially as high as 800 keV.

  5. Prospects for advanced electron cyclotron resonance and electron beam ion source charge breeding methods for EURISOL

    Energy Technology Data Exchange (ETDEWEB)

    Delahaye, P.; Jardin, P.; Maunoury, L.; Traykov, E.; Varenne, F. [GANIL, CEA/DSM-CNRS/IN2P3, Bd. Becquerel, BP 55027, 14076 Caen Cedex 05 (France); Galata, A.; Porcellato, A. M.; Prete, G. F. [INFN-Laboratori Nazionali di Legnaro, Viale dell' Universita 2, 35020 Legnaro, Padova (Italy); Angot, J.; Lamy, T.; Sortais, P.; Thuillier, T. [LPSC Grenoble, 53, rue des Martyrs, 38026 Grenoble Cedex (France); Ban, G. [LPC Caen, 6 bd Marechal Juin, 14050 Caen Cedex (France); Celona, L.; Lunney, D. [INFN-Laboratori Nazionali del Sud, via S.Sofia 62, 95125 Catania (Italy); Choinski, J.; Gmaj, P.; Jakubowski, A.; Steckiewicz, O. [Heavy Ion Laboratory, University of Warsaw, ul. Pasteura 5a, 02 093 Warsaw (Poland); Kalvas, T. [Department of Physics, University of Jyvaeskylae, PB 35 (YFL) 40351 Jyvaeskylae (Finland); and others

    2012-02-15

    As the most ambitious concept of isotope separation on line (ISOL) facility, EURISOL aims at producing unprecedented intensities of post-accelerated radioactive isotopes. Charge breeding, which transforms the charge state of radioactive beams from 1+ to an n+ charge state prior to post-acceleration, is a key technology which has to overcome the following challenges: high charge states for high energies, efficiency, rapidity and purity. On the roadmap to EURISOL, a dedicated R and D is being undertaken to push forward the frontiers of the present state-of-the-art techniques which use either electron cyclotron resonance or electron beam ion sources. We describe here the guidelines of this R and D.

  6. Multiplicity of secondary electrons emitted by carbon thin targets by impact of H{sup 0}, H{sub 2}{sup +} and H{sub 3}{sup +} projectiles at MeV energies; Multiplicite des electrons secondaires emis par des cibles minces de carbone sous l`impact de projectiles H{sup 0}, H{sub 2}{sup +} et H{sub 3}{sup +} d`energie de l`ordre du MeV

    Energy Technology Data Exchange (ETDEWEB)

    Vidovic, Zvonimir [Inst. de Physique Nucleaire, Lyon-1 Univ., 69 - Villeurbanne (France)

    1997-06-24

    This work focuses on the study of the emission statistics of secondary electrons from thin carbon foils bombarded with H{sup 0}, H{sub 2}{sup +} and H{sub 3}{sup +} projectiles in the 0.25 - 2.2 MeV energy range. The phenomenon of secondary electron emission from solids under the impact of swift ions is mainly due to inelastic interactions with target electrons. Phenomenological and theoretical descriptions as well as a summary of the main theoretical models are the subjects of the first chapter. The experimental set-up used to measure event by event the electron emission of the two faces of the thin carbon foils crossed by an energetic projectile is described in the chapter two. In this chapter there are also presented the method and the algorithms used to process experimental spectra in order to obtain the statistical distribution of the emitted electrons. Chapter three presents the measurements of secondary electron emission induced by H{sup 0} atoms passing through thin carbon foils. The secondary electron yields are studied in correlation with emergent projectile charge state. We show the peculiar role of the projectile electron, whether it remains or not bound to the incident proton. The fourth chapter is dedicated to the secondary electron emission induced by H{sub 2}{sup +} and H{sub 3}{sup +} polyatomic ions. The results are interpreted in terms of collective effects in the interactions of the ions with solids. The role of the proximity of the protons, molecular ions fragments, upon the amplitude of these collected effects is evidenced from the study of the statistics of forward emission. The experiments allowed us to shed light on various aspects of atom and polyatomic ion interactions with solid surfaces. (author) 136 refs., 41 figs., 3 tabs.

  7. The sciences and applications of the Electron LINAC-driven neutron source in Argentina

    Science.gov (United States)

    Granada, J. R.; Mayer, R. E.; Dawidowski, J.; Santisteban, J. R.; Cantargi, F.; Blostein, J. J.; Rodríguez Palomino, L. A.; Tartaglione, A.

    2016-06-01

    The Neutron Physics group at Centro Atómico Bariloche (CNEA, Argentina) has evolved for more than forty five years around a small 25MeV linear electron accelerator. It constitutes our compact accelerator-driven neutron source (CANS), which is dedicated to the use and development of neutronic methods to tackle problems of basic sciences and technological applications. Its historical first commitment has been the determination of the total cross sections of materials as a function of neutron energy by means of transmission experiments for thermal and sub-thermal neutrons. This also allowed testing theoretical models for the generation of scattering kernels and cross sections. Through the years, our interests moved from classic pulsed neutron diffraction, which included the development of high-precision methods for the determination of very low hydrogen content in metals, towards deep inelastic neutron scattering (DINS), a powerful tool for the determination of atomic momentum distribution in condensed matter. More recently non-intrusive techniques aimed at the scanning of large cargo containers have started to be developed with our CANS, testing the capacity and limitations to detect special nuclear material and dangerous substances. Also, the ever-present "bremsstrahlung" radiation has been recognized and tested as a useful complement to instrumental neutron activation, as it permits to detect other nuclear species through high-energy photon activation. The facility is also used for graduate and undergraduate students' experimental work within the frame of Instituto Balseiro Physics and Nuclear Engineering courses of study, and also MSc and PhD theses work.

  8. Charge breeding results and future prospects with electron cyclotron resonance ion source and electron beam ion source (invited).

    Science.gov (United States)

    Vondrasek, R; Levand, A; Pardo, R; Savard, G; Scott, R

    2012-02-01

    The Californium Rare Ion Breeder Upgrade (CARIBU) of the Argonne National Laboratory ATLAS facility will provide low-energy and reaccelerated neutron-rich radioactive beams for the nuclear physics program. A 70 mCi (252)Cf source produces fission fragments which are thermalized and collected by a helium gas catcher into a low-energy particle beam with a charge of 1+ or 2+. An electron cyclotron resonance (ECR) ion source functions as a charge breeder in order to raise the ion charge sufficiently for acceleration in the ATLAS linac. The final CARIBU configuration will utilize a 1 Ci (252)Cf source to produce radioactive beams with intensities up to 10(6) ions∕s for use in the ATLAS facility. The ECR charge breeder has been tested with stable beam injection and has achieved charge breeding efficiencies of 3.6% for (23)Na(8+), 15.6% for (84)Kr(17+), and 13.7% for (85)Rb(19+) with typical breeding times of 10 ms∕charge state. For the first radioactive beams, a charge breeding efficiency of 11.7% has been achieved for (143)Cs(27+) and 14.7% for (143)Ba(27+). The project has been commissioned with a radioactive beam of (143)Ba(27+) accelerated to 6.1 MeV∕u. In order to take advantage of its lower residual contamination, an EBIS charge breeder will replace the ECR charge breeder in the next two years. The advantages and disadvantages of the two techniques are compared taking into account the requirements of the next generation radioactive beam facilities.

  9. The effect of magnetic field strength on the time evolution of high energy bremsstrahlung radiation created by an electron cyclotron resonance ion source

    Energy Technology Data Exchange (ETDEWEB)

    Ropponen, T. [Department of Physics, University of Jyvaeskylae, P.O. Box 35, FI-40014 (Finland)], E-mail: tommi.ropponen@phys.jyu.fi; Tarvainen, O. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Jones, P.; Peura, P.; Kalvas, T. [Department of Physics, University of Jyvaeskylae, P.O. Box 35, FI-40014 (Finland); Suominen, P. [Prizztech Ltd/Magnet Technology Centre, Tiedepuisto 4, FI-28600 Pori (Finland); Koivisto, H.; Arje, J. [Department of Physics, University of Jyvaeskylae, P.O. Box 35, FI-40014 (Finland)

    2009-03-11

    An electron cyclotron resonance (ECR) ion source is one of the most used ion source types for high charge state heavy ion production. In ECR plasma the electrons are heated by radio frequency microwaves in order to provide ionization of neutral gases. As a consequence, ECR heating also generates very high electron energies (up to MeV region) which can produce a vast amount of bremsstrahlung radiation causing problems with radiation shielding and heating superconducting cryostat of an ECR ion source. To gain information about the time evolution of the electron energies in ECR plasma radial bremsstrahlung measurements were performed. JYFL 14 GHz ECR ion source was operated in pulsed mode and time evolution measurements were done with different axial magnetic field strengths with oxygen and argon plasmas. Bremsstrahlung data were analyzed with a time interval of 2 ms yielding information at unprecedented detail about the time evolution of high energy bremsstrahlung radiation from an ECR ion source. It was observed, for example, that reaching the steady state phase of the plasma bremsstrahlung requires several hundred milliseconds and the steady state time can be different with different gases.

  10. ELECTRON BEAM ION SOURCE PREINJECTOR PROJECT (EBIS) CONCEPTUAL DESIGN REPORT.

    Energy Technology Data Exchange (ETDEWEB)

    ALESSI, J.; BARTON, D.; BEEBE, E.; GASSNER, D.; GRANDINETTI, R.; HSEUH, H.; JAVIDFAR, A.; KPONOU, A.; LAMBIASE, R.; LESSARD, E.; LOCKEY, R.; LODESTRO, V.; MAPES, M.; MIRABELLA, D.; NEHRING, T.; OERTER, B.; PENDZICK, A.; PIKIN, A.; RAPARIA, D.; RITTER, J.; ROSER, T.; RUSSO, T.; SNYDSTRUP, L.; WILINSKI, M.; ZALTSMAN, A.; ZHANG, S.

    2005-09-01

    This report describes a new heavy ion pre-injector for the Relativistic Heavy Ion Collider (RHIC) based on a high charge state Electron Beam Ion Source (EBIS), a Radio Frequency Quadrupole (RFQ) accelerator, and a short Linear accelerator (Linac). The highly successful development of an EBIS at Brookhaven National Laboratory (BNL) now makes it possible to replace the present pre-injector that is based on an electrostatic Tandem with a reliable, low maintenance Linac-based pre-injector. Linac-based preinjectors are presently used at most accelerator and collider facilities with the exception of RHIC, where the required gold beam intensities could only be met with a Tandem until the recent EBIS development. EBIS produces high charge state ions directly, eliminating the need for the two stripping foils presently used with the Tandem. Unstable stripping efficiencies of these foils are a significant source of luminosity degradation in RHIC. The high reliability and flexibility of the new Linac-based pre-injector will lead to increased integrated luminosity at RHIC and is an essential component for the long-term success of the RHIC facility. This new pre-injector, based on an EBIS, also has the potential for significant future intensity increases and can produce heavy ion beams of all species including uranium beams and, as part of a future upgrade, might also be used to produce polarized {sup 3}He beams. These capabilities will be critical to the future luminosity upgrades and electron-ion collisions in RHIC. The proposed pre-injector system would also provide for a major enhancement in capability for the NASA Space Radiation Laboratory (NSRL), which utilizes heavy-ion beams from the RHIC complex. EBIS would allow for the acceleration of all important ion species for the NASA radiobiology program, such as, helium, argon, and neon which are unavailable with the present Tandem injector. In addition, the new system would allow for very rapid switching of ion species for

  11. Effect of 8 MeV electron irradiation on the performance of CSS grown CdTe/CdS solar cells

    Science.gov (United States)

    Krishnan, Sheeja; Sanjeev, Ganesh; Pattabi, Manjunatha; Ullal, Harin S.; Wu, Xuanzhi

    2007-12-01

    The results of investigations carried out on the effect of electron irradiation on the electrical properties of CdTe/CdS solar cells prepared by close spaced sublimation (CSS) are presented in this paper. The solar cells were characterized using current-voltage (I-V) measurements under dark and air mass (AM) 1.5 illumination conditions. They were also characterized by capacitance measurements at various frequencies. The cells were exposed to graded doses of electrons up to 100 kGy. The effect of electron irradiation on the solar cell parameters such as short circuit current (Isc), open circuit voltage (Voc), fill factor (FF), conversion efficiency (η), saturation current (Io) and ideality factor (n) were studied. Only small changes in the cell parameters were observed after electron irradiation. Since the observed changes in the cell parameters were not remarkable up to an electron dose of 100 kGy, CdTe/CdS solar cells seem to be stable under electron irradiation.

  12. 14 MeV neutrons physics and applications

    CERN Document Server

    Valkovic, Vladivoj

    2015-01-01

    Despite the often difficult and time-consuming effort of performing experiments with fast (14 MeV) neutrons, these neutrons can offer special insight into nucleus and other materials because of the absence of charge. 14 MeV Neutrons: Physics and Applications explores fast neutrons in basic science and applications to problems in medicine, the environment, and security.Drawing on his more than 50 years of experience working with 14 MeV neutrons, the author focuses on:Sources of 14 MeV neutrons, including laboratory size accelerators, small and sealed tube generators, well logging sealed tube ac

  13. Note: Thermal analysis of the long line source electron gun

    Science.gov (United States)

    Iqbal, M.; Wasy, A.; Lodhi, M. A. K.

    2013-05-01

    We performed thermal analysis for our previously reported [M. Iqbal, K. Masood, M. Rafiq, M. A. Chaudhry, and F. Aleem, Rev. Sci. Instrum. 74, 4616 (2003), 10.1063/1.1614852], long linear filament electron gun assembly using ANSYS software. The source was set under a thermal load of 3000 °C, to evaluate temperature distribution, thermal strain, and heat flux at various components of the gun. We calculated the maximum heat flux (9.0 W/mm2) that produced a thermal strain of 0.05 at the focusing electrodes. However, the minimum value of the heat flux (0.3 W/mm2) was at the anode electrodes which correspond to a negligible thermal strain. The gun was validated experimentally showing a uniform cross section of the beam at the molybdenum work plate comparable to the size of the filament. Our experimental and theoretical results are in agreement. The gun had been in continuous operation for several hours at high temperatures without any thermal run-out.

  14. Particle-In-Cell Simulations of the Electron Beam Source for X-Ray Radiography Generated by the Rod-Pinch Diode in the Cygnus Experiment

    Science.gov (United States)

    Yin, Lin; Kwan, Thomas; Devolder, Barbara; Berninger, Mike; Bowers, Kevin; Smith, John

    2003-10-01

    The Cygnus experiment [Smith et al., AIP Conference Proceedings, 650, 135, 2002] is in operation at Los Alamos National Laboratory to support the Sub-Critical Experiments Program at the Nevada Test Site. In the Cygnus design, a rod-pinch diode is used to produce a low-energy (up to ˜ 2.25 MeV) radiographic electron source at the tip of a needle anode rod that extends through an annular cathode. As the electrons deposit their energies on the high-Z anode tip, bremsstrahlung photons are produced and are used to generate radiographs of an object. In this work we use the two-dimensional particle-in-cell code MERLIN to examine the diode physics and the dynamics of the rod-pinch electron source which is used in integrated X-ray radiographic chain model calculations [Kwan et al., Comp. Phys. Comm., 142, 263, 2001]. TEM waves are launched at one simulation boundary to set up the voltage required for the electron emission. Electron and ion trajectories are followed self-consistently in the electromagnetic fields as the electron beam impinges at the tip of the anode rod. The MERLIN simulation results of the electron endpoint energy and the diode voltage/current are consistent with the peak values obtained from Cygnus shots. The diode impedance response to the experimental parameters currently used in the Cygnus shots will be discussed.

  15. Electron loss from 1.4 MEV/u U{sup 4,6,10+} ions colliding with Ne, N{sub 2} and Ar targets

    Energy Technology Data Exchange (ETDEWEB)

    DuBois, R.D. [Missouri Univ., Rolla, MO (United States); Santos, A.C.F. [Centro Federal de Educacao Tecnologica de Quimica, Rio de Janeiro (Brazil); Stoehlker, T. [Gesellschaft fuer Schwerionenforschung mbH, Darmstadt (DE). Abt. Atomphysik] [and others

    2004-07-01

    Absolute, total, single, and multiple electron loss cross sections are measured for 1.4 MeV/u U{sup 4,6,10+} ions colliding with neon and argon atoms and nitrogen molecules. It is found that the cross sections all have the same dependence on the number of electrons lost and that multiplying the cross sections by the initial number of electrons in the 6s, 6p, and 5f shells yields good agreement between the different projectiles. By combining the present data with previous measurements made at the same velocity, it is shown that the scaled cross sections slowly decrease in magnitude for incoming charge states between 1 and 10 whereas the cross sections for higher charge state ions fall off much more rapidly. (orig.)

  16. An image-based skeletal dosimetry model for the ICRP reference adult female—internal electron sources

    Science.gov (United States)

    O'Reilly, Shannon E.; DeWeese, Lindsay S.; Maynard, Matthew R.; Rajon, Didier A.; Wayson, Michael B.; Marshall, Emily L.; Bolch, Wesley E.

    2016-12-01

    An image-based skeletal dosimetry model for internal electron sources was created for the ICRP-defined reference adult female. Many previous skeletal dosimetry models, which are still employed in commonly used internal dosimetry software, do not properly account for electron escape from trabecular spongiosa, electron cross-fire from cortical bone, and the impact of marrow cellularity on active marrow self-irradiation. Furthermore, these existing models do not employ the current ICRP definition of a 50 µm bone endosteum (or shallow marrow). Each of these limitations was addressed in the present study. Electron transport was completed to determine specific absorbed fractions to both active and shallow marrow of the skeletal regions of the University of Florida reference adult female. The skeletal macrostructure and microstructure were modeled separately. The bone macrostructure was based on the whole-body hybrid computational phantom of the UF series of reference models, while the bone microstructure was derived from microCT images of skeletal region samples taken from a 45 years-old female cadaver. The active and shallow marrow are typically adopted as surrogate tissue regions for the hematopoietic stem cells and osteoprogenitor cells, respectively. Source tissues included active marrow, inactive marrow, trabecular bone volume, trabecular bone surfaces, cortical bone volume, and cortical bone surfaces. Marrow cellularity was varied from 10 to 100 percent for active marrow self-irradiation. All other sources were run at the defined ICRP Publication 70 cellularity for each bone site. A total of 33 discrete electron energies, ranging from 1 keV to 10 MeV, were either simulated or analytically modeled. The method of combining skeletal macrostructure and microstructure absorbed fractions assessed using MCNPX electron transport was found to yield results similar to those determined with the PIRT model applied to the UF adult male skeletal dosimetry model. Calculated

  17. Carbon Nanotube Electron Sources for Air Purification Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The innovation proposed here focuses on cleansing air with high energy electrons. Bombardment by electrons has proven to be effective in removing a wide spectrum of...

  18. Energy‐dependent dynamics of keV to MeV electrons in the inner zone, outer zone, and slot regions

    Science.gov (United States)

    Friedel, Reiner H. W.; Larsen, Brian A.; Skoug, Ruth M.; Funsten, Herbert O.; Claudepierre, Seth G.; Fennell, Joseph F.; Turner, Drew L.; Denton, Mick H.; Spence, Harlan E.; Blake, J. Bernard; Baker, Daniel N.

    2016-01-01

    Abstract We present observations of the radiation belts from the Helium Oxygen Proton Electron and Magnetic Electron Ion Spectrometer particle detectors on the Van Allen Probes satellites that illustrate the energy dependence and L shell dependence of radiation belt enhancements and decays. We survey events in 2013 and analyze an event on 1 March in more detail. The observations show the following: (a) at all L shells, lower energy electrons are enhanced more often than higher energies; (b) events that fill the slot region are more common at lower energies; (c) enhancements of electrons in the inner zone are more common at lower energies; and (d) even when events do not fully fill the slot region, enhancements at lower energies tend to extend to lower L shells than higher energies. During enhancement events the outer zone extends to lower L shells at lower energies while being confined to higher L shells at higher energies. The inner zone shows the opposite with an outer boundary at higher L shells for lower energies. Both boundaries are nearly straight in log(energy) versus L shell space. At energies below a few 100 keV, radiation belt electron penetration through the slot region into the inner zone is commonplace, but the number and frequency of “slot filling” events decreases with increasing energy. The inner zone is enhanced only at energies that penetrate through the slot. Energy‐ and L shell‐dependent losses (that are consistent with whistler hiss interactions) return the belts to more quiescent conditions.

  19. Strong radiation damping effects in a gamma-ray source generated by the interaction of a high intensity laser with a wakefield accelerated electron beam

    Science.gov (United States)

    Thomas, Alexander; Ridgers, Christopher; Bulanov, Stepan; Griffin, Blake; Mangles, Stuart

    2012-10-01

    We present numerical calculations of the angularly resolved radiation spectrum from a relativistic electron beam interacting with an ultrashort laser pulse. These calculations include the effect of semi-classical radiation reaction forces including a Gaunt factor for synchrotron radiation. For a laser of 5x10^21 Wcm-2 intensity interacting with a 200 MeV electron beam with an emittance similar to that in laser wakefield acceleration experiments, radiation reaction does not produce a significant change in the angular and energy distribution of photons. However the effects of radiation reaction are clear when observing the electron beam properties. The result is that near-term experiments using such a counter-propagating beam-laser geometry should be able to measure the effects of quantum effects in radiation reaction. The calculations also show that the brilliance of this source is very high, with a peak spectral brilliance exceeding 10^29 photons,s-1mm-2mrad-2(0.1% bandwidth)-1 with approximately 2% efficiency and with a peak energy of 10 MeV.

  20. Electron Sources for Future Lightsources, Summary and Conclusions for the Activities during FLS 2012

    CERN Document Server

    Kamps, Thorsten; Boulware, Chase; Corlett, John; Harkay, Katherine; Hannon, Fay; Krasilnikov, Mikhail; Militsyn, Boris; Quast, Torsten; Sannibale, Fernando; Teichert, Jochen

    2013-01-01

    This paper summarizes the discussions, presentations, and activity of the (Future Light Sources Workshop 2012) FLS 2012 working group dedicated to Electron Sources. The focus of the working group was to discuss concepts and technologies that might enable much higher peak and average brightness from electron beam sources. Furthermore the working group was asked to consider methods to greatly improve the robustness of operation and lower the costs of providing electrons.

  1. Roos and NACP-02 ion chamber perturbations and water-air stopping-power ratios for clinical electron beams for energies from 4 to 22 MeV.

    Science.gov (United States)

    Bailey, M; Shipley, D R; Manning, J W

    2015-02-07

    Empirical fits are developed for depth-compensated wall- and cavity-replacement perturbations in the PTW Roos 34001 and IBA / Scanditronix NACP-02 parallel-plate ionisation chambers, for electron beam qualities from 4 to 22 MeV for depths up to approximately 1.1 × R₅₀,D. These are based on calculations using the Monte Carlo radiation transport code EGSnrc and its user codes with a full simulation of the linac treatment head modelled using BEAMnrc. These fits are used with calculated restricted stopping-power ratios between air and water to match measured depth-dose distributions in water from an Elekta Synergy clinical linear accelerator at the UK National Physical Laboratory. Results compare well with those from recent publications and from the IPEM 2003 electron beam radiotherapy Code of Practice.

  2. Table-top laser-driven ultrashort electron and X-ray source: the CIBER-X source project

    Science.gov (United States)

    Girardeau-Montaut, Jean-Pierre; Kiraly, Bélà; Girardeau-Montaut, Claire; Leboutet, Hubert

    2000-09-01

    We report on the development of a new laser-driven table-top ultrashort electron and X-ray source, also called the CIBER-X source . X-ray pulses are produced by a three-step process which consists of the photoelectron emission from a thin metallic photocathode illuminated by 16 ps duration laser pulses at 213 nm. The e-gun is a standard Pierce diode electrode type, in which electrons are accelerated by a cw electric field of ˜11 MV/m up to a hole made in the anode. The photoinjector produces a train of 70-80 keV electron pulses of ˜0.5 nC and 20 A peak current at a repetition rate of 10 Hz. The electrons are then transported outside the diode along a path of 20 cm length, and are focused onto a target of thullium by magnetic fields produced by two electromagnetic coils. X-rays are then produced by the impact of electrons on the target. Simulations of geometrical, electromagnetic fields and energetic characteristics of the complete source were performed previously with the assistance of the code PIXEL1 also developed at the laboratory. Finally, experimental electron and X-ray performances of the CIBER-X source as well as its application to very low dose imagery are presented and discussed. source Compacte d' Impulsions Brèves d' Electrons et de Rayons X

  3. RF-driven ion source with a back-streaming electron dump

    Science.gov (United States)

    Kwan, Joe; Ji, Qing

    2014-05-20

    A novel ion source is described having an improved lifetime. The ion source, in one embodiment, is a proton source, including an external RF antenna mounted to an RF window. To prevent backstreaming electrons formed in the beam column from striking the RF window, a back streaming electron dump is provided, which in one embodiment is formed of a cylindrical tube, open at one end to the ion source chamber and capped at its other end by a metal plug. The plug, maintained at the same electrical potential as the source, captures these backstreaming electrons, and thus prevents localized heating of the window, which due to said heating, might otherwise cause window damage.

  4. Ultrafast Time-Resolved Electron Diffraction with Megavolt Electron Beams

    Energy Technology Data Exchange (ETDEWEB)

    Hastings, J.B.; /SLAC; Rudakov, F.M.; /Brown U.; Dowell, D.H.; Schmerge, J.F.; /SLAC; Cardoza, J.D.; /Brown U.; Castro, J.M.; Gierman, S.M.; Loos, H.; /SLAC; Weber, P.M.; /Brown U.

    2006-10-24

    An rf photocathode electron gun is used as an electron source for ultrafast time-resolved pump-probe electron diffraction. We observed single-shot diffraction patterns from a 160 nm Al foil using the 5.4 MeV electron beam from the Gun Test Facility at the Stanford Linear Accelerator. Excellent agreement with simulations suggests that single-shot diffraction experiments with a time resolution approaching 100 fs are possible.

  5. Absorbed Dose Distributions in Small Copper Wire Insulation due to Multiple-Sided Irradiations by 0.4 MeV Electrons

    DEFF Research Database (Denmark)

    Miller, Arne; McLaughlin, W. L.; Pedersen, Walther Batsberg

    1979-01-01

    When scanned electron beams are used to crosslink polymeric insulation of wire and cable, an important goal is to achieve optimum uniformity of absorbed dose distributions. Accurate measurements of dose distributions in a plastic dosimeter simulating a typical insulating material (polyethylene....... and insulation thicknesses between 0.4 and 0.8 mm. The plastic dosimeter simulating polyethylene insulations was a thin radiochromic polyvinyl butyral film wrapped several times around the copper wire, such that when unwrapped and analyzed optically on a scanning microspectrophotometer, high-resolution radial...

  6. 6 MeV storage ring dedicated to hard X-ray imaging and far-infrared spectroscopy

    Indian Academy of Sciences (India)

    M M Haque; A Moon; T Hirai; H Yamada

    2011-02-01

    The tabletop storage ring, 6 MeV MIRRORCLE, is dedicated to hard X-ray imaging as well as far-infrared (FIR) spectroscopy. In spite of low electron energy, the 6 MeV MIRRORCLE generates hard X-rays ranging from 10 keV up to its electron energy and milliwatt order submillimetre range FIR rays. Bremsstrahlung is the mechanism for the hard X-ray generation. Images produced with 11 × geometrical magnification display a sharply enhanced edge effect when generated using a 25 mm rod electron target. Bright far-infrared is generated in the same way using a conventional synchrotron light source, but with MIRRORCLE the spectral flux is found to be ∼ 1000 times greater than that of a standard thermal source. Partially coherent enhancement is observed in the case of FIR output.

  7. Commissioning of a 6 MeV X-Band SW Accelerating Guide

    CERN Document Server

    Jin, Q; Sun, X; Tao, X; Tong, D

    2004-01-01

    A 6 MeV, X-band on-axis SW electron linear accelerating guide is being developed in Accelerator laboratory of Tsinghua University. It can be suitable for portable radiation therapy and radiography. The design, manufacture and high power test of the guide are given in this paper. The guide is 38 cm long and contains 25 accelerating cells with 24 coupling cells, operated in the π/2 mode. The RF power source is a pulsed magnetron at 9300 MHz with 1.5 MW peak power. The results of beam tests are following: the electron energy is more than 6 MeV at 50 mA and focal spot size is less than φ 1.5 mm without any focusing solenoid.

  8. Electronic neutron sources for compensated porosity well logging

    Energy Technology Data Exchange (ETDEWEB)

    Chen, A. X.; Antolak, A. J.; Leung, K. -N.

    2012-08-01

    The viability of replacing Americium–Beryllium (Am–Be) radiological neutron sources in compensated porosity nuclear well logging tools with D–T or D–D accelerator-driven neutron sources is explored. The analysis consisted of developing a model for a typical well-logging borehole configuration and computing the helium-3 detector response to varying formation porosities using three different neutron sources (Am–Be, D–D, and D–T). The results indicate that, when normalized to the same source intensity, the use of a D–D neutron source has greater sensitivity for measuring the formation porosity than either an Am–Be or D–T source. The results of the study provide operational requirements that enable compensated porosity well logging with a compact, low power D–D neutron generator, which the current state-of-the-art indicates is technically achievable.

  9. Electronic neutron sources for compensated porosity well logging

    Energy Technology Data Exchange (ETDEWEB)

    Chen, A.X., E-mail: axchen@sandia.gov [Sandia National Laboratories, Livermore, CA 94550 (United States); Antolak, A.J.; Leung, K.-N. [Sandia National Laboratories, Livermore, CA 94550 (United States)

    2012-08-21

    The viability of replacing Americium-Beryllium (Am-Be) radiological neutron sources in compensated porosity nuclear well logging tools with D-T or D-D accelerator-driven neutron sources is explored. The analysis consisted of developing a model for a typical well-logging borehole configuration and computing the helium-3 detector response to varying formation porosities using three different neutron sources (Am-Be, D-D, and D-T). The results indicate that, when normalized to the same source intensity, the use of a D-D neutron source has greater sensitivity for measuring the formation porosity than either an Am-Be or D-T source. The results of the study provide operational requirements that enable compensated porosity well logging with a compact, low power D-D neutron generator, which the current state-of-the-art indicates is technically achievable.

  10. Energy spectra of plasma sheet ions and electrons from about 50 eV/e to about 1 MeV during plamsa temperature transitions

    Science.gov (United States)

    Christon, S. P.; Mitchell, D. G.; Williams, D. J.; Frank, L. A.; Huang, C. Y.; Eastman, T. E.

    1988-01-01

    ISEE-1 charged-particle measurements obtained during eight plasma temperature transitions (PTTs) in 1978-1979 are compiled in tables and graphs and analyzed in detail, comparing the ion and electron differential energy spectra with the predictions of theoretical models. PTTs are defined as approximately 1-h periods of low bulk plasma velocity and steadily increasing or decreasing thermal energy. A Maxwellian distribution is found to be inadequate in describing the PTT energy spectra, but velocity-exponential and kappa distributions are both successful, the latter especially at higher energies. The power-law index kappa varies from PTT to PTT, but the high-energy spectral index and overall shape of the distribution remain constant during a PTT; both spatial and temporal effects are observed.

  11. Potential applications of an electron cyclotron resonance multicusp plasma source

    Energy Technology Data Exchange (ETDEWEB)

    Tsai, C.C.; Berry, L.A.; Gorbatkin, S.M.; Haselton, H.H.; Roberto, J.B.; Schechter, D.E.; Stirling, W.L.

    1990-03-01

    An electric cyclotron resonance (ECR) multicusp plasmatron has been developed by feeding a multicusp bucket arc chamber with a compact ECR plasma source. This novel source produces large (about 25-cm- diam), uniform (to within {plus minus}10%), dense (>10{sup 11}--cm{sup {minus}3}) plasmas of argon, helium, hydrogen, and oxygen. It has been operated to produce an oxygen plasma for etching 12.7-cm (5-in.) positive photoresist-coated silicon wafers with uniformity within {plus minus}8%. Following a brief review of the large plasma source developed at Oak Ridge National Laboratory, the configuration and operation of the source are described and a discharge model is presented. Results from this new ECR plasma source and potential applications for plasma processing of thin films are discussed. 21 refs., 10 figs.

  12. Simulation of Electron Trajectories in the Multicusp Ion Source Using Geantn4 Monte Carlo Code

    Science.gov (United States)

    Khodadadi Azadboni, Fatemeh; Sedaghatizade, Mahmood

    2010-04-01

    To optimize the multicusp ion source, understanding of transport properties of electrons is indispensable. Since the transport of electrons in the multicusp ion source is a three-dimensional problem, we use the 3D computer code Geant4, to model the particle trajectories. The goal is to study the effect of electron injection into a cylindrical gas chamber and the electron trajectories. The role of the magnetic filter in contemporary negative ion sources is analyzed. The conditions in the magnetic filter adjacent to the plasma electrode optimum for the generation, formation, and extraction of an H- ion beam are found. The simulation results are in good agreement with the experimental data.

  13. Numerical simulation of a triode source of intense radial converging electron beam

    Science.gov (United States)

    Altsybeyev, V.; Engelko, V.; Ovsyannikov, A.; Ovsyannikov, D.; Ponomarev, V.; Fetzer, R.; Mueller, G.

    2016-10-01

    The results of numerical simulations of a triode source of an intense radial converging electron beam are presented. The role of the initial transverse velocity of electrons, defocusing effect of the controlling grid, the beam self-magnetic field, backscattering of electrons, and ion flow from the target is analyzed. It was found that the ion flow from the target essentially increases the value of the electron current. The influence of the beam self-magnetic field on electron trajectories leads to the fact that there is a critical value of the cathode-grid voltage dividing the mode of the source operation into stable and unstable. The influence of initial transverse electron energies on the beam focusing is essentially higher than the influence of the controlling grid. Backscattering of the beam electrons from the target surface increases the target ion current so that the source operation may become unstable and the distribution of the beam power density on the target becomes nonuniform with a maximum in the center. Electrons passing by the target drift along the source axis. This leads to diminishing the power density at the center of the target and to the exit of peripheral electrons from the source. Conditions for achieving required electron beam parameters (the electron kinetic energy—120 keV, the beam energy density on the target ˜40 J/cm2 on a maximum possible length of the target surface) were determined.

  14. Electron beam treatment of non-conducting materials by a fore-pump-pressure plasma-cathode electron beam source

    Energy Technology Data Exchange (ETDEWEB)

    Burdovitsin, V A; Klimov, A S; Medovnik, A V; Oks, E M, E-mail: burdov@fet.tusur.r [Tomsk State University of Control Systems and Radioelectronics, 634050, 40 Lenin Ave., Tomsk (Russian Federation)

    2010-10-15

    In the irradiation of an insulated target by an electron beam produced by a plasma-cathode electron beam source operating in the fore-vacuum pressure range (5-15 Pa), the target potential is much lower than the electron beam energy, offering the possibility of direct electron treatment of insulating materials. It is found that in the electron beam irradiation of a non-conducting target in a moderately high pressure range, the electron charge on the target surface is neutralized mainly by ions from a volume discharge established between the negatively charged target surface and the grounded walls of the vacuum chamber. This allows the possibility of direct electron beam treatment (heating, melting, welding) of ceramics and other non-conducting and semiconductor materials.

  15. Requirements on the LWFA electron beam for the user-oriented photon source

    Science.gov (United States)

    Molodozhentsev, Alexander; Přibyl, Lukáš; Korn, Georg; Winkler, Paul; Maier, Andreas R.

    2017-05-01

    The laser-driven Undulator X-ray source (LUX) is designed to be a user beamline providing ultra-short EUV photon pulses with a central wavelength tuneable in the range of 0.4 to 4.5 nm and a peak brilliance of up to 1021 photons/(s.mrad2.mm2.0.1% B.W.), which makes this source comparable with modern synchrotron sources. The source shall provide a focal spot size well below 10 μm and a range of auxiliary beams for complex pump-and-probe experiments and it is also an important experimental milestone towards a future laser driven Free Electron Laser. Unique femtosecond nature of the laser-plasma electron acceleration in combination with extremely small transverse emittance of the electron beam is the major advantage of the LWFA technique. Preservation of the electron beam quality is a complicated task for a dedicated electron beam line, which has to be designed to transport the electron beam from the LWFA source up to the undulator. In this report we discuss main requirements on the LWFA source and the electron beam optics of the LUX source and solutions to produce required quality photon beam in the undulator and we also discuss the effect of realistic setup parameters on the quality of the electron beam in the undulator within the range of systematic errors.

  16. ROLE OF DIAMOND SECONDARY EMITTERS IN HIGH BRIGHTNESS ELECTRON SOURCES.

    Energy Technology Data Exchange (ETDEWEB)

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

    2005-09-20

    In this paper we explore the possibility of using diamond secondary emitter in a high average current electron injector to amplify the current from the photocathode and to isolate the cathode and the injector from each other to increase the life time of the cathode and preserve the performance of the injector. Secondary electron yield of 225 and current density of 0.8 a/cm{sup 2} have been measured in the transmission mode from type 2 a natural diamond. Although the diamond will be heated during normal operation in the injector, calculations indicate that by cryogenically cooling the diamond, the temperature gradient along the diamond can be maintained within the acceptable range. The electron energy and temporal distributions are expected to be narrow from this device resulting in high brightness beams. Plans are underway to measure the SEY in emission mode, fabricate photocathode-diamond capsule and test diamond and capsule in superconducting RF injector.

  17. Terahertz radiation source using an industrial electron linear accelerator

    CERN Document Server

    Kalkal, Yashvir

    2015-01-01

    High power ($\\sim 100$ kW) industrial electron linear accelerators (linacs) are used for irradiation applications e.g., for pasteurization of food products, disinfection of medical waste, etc. We propose that high power electron beam from such an industrial linac can be first passed through an undulator to generate powerful terahertz (THz) radiation, and the spent electron beam coming out of the undulator can still be used for industrial applications. This will enhance the utilisation of a high power industrial linac. We have performed calculation of spontaneous emission in the undulator to show that for typical parameters, continuous terahertz radiation having power of the order of $\\mu$W can be produced, which may be useful for many scientific applications.

  18. Compact Electron-Linac Design Concept for a Gamma Ray Source

    CERN Document Server

    Chan, K C D; Dale, G; Garnett, R; Kirbie, C; Krawczyk, F L; Russell, S J; Wangler, T P

    2004-01-01

    Gamma-ray sources, particularly sources that are easily transportable, are in high demand for different homeland security applications. We have carried out a review of commercially available electron-linac-based sources, and have investigated alternative compact electron-linac systems that use updated technologies compared with sources that are available commercially. As the results, we propose to develop a new source using an electron linac operating at 17 GHz. It uses a klystron, instead of a magnetron, and a IGBT-switched HV power supply. The source design takes advantages of the advances in X-band linac technology and solid-state HV technology. The higher frequency and upgraded technologies offer smaller size, lighter weight, better efficiency, easier operation, and higher reliability, compared with commercially-available linacs. In this paper, we will describe the source design and our choice of technologies.

  19. Fast electron slowing-down and diffusion in a high temperature coronal X-ray source

    CERN Document Server

    Galloway, R K; Kontar, E P; Helander, P; Galloway, Ross K.; Kinnon, Alexander L. Mac; Kontar, Eduard P.; Helander, Per

    2005-01-01

    Finite thermal velocity modifications to electron slowing-down rates may be important for the deduction of solar flare total electron energy. Here we treat both slowing-down and velocity diffusion of electrons in the corona at flare temperatures, for the case of a simple, spatially homogeneous source. Including velocity diffusion yields a consistent treatment of both `accelerated' and `thermal' electrons. It also emphasises that one may not invoke finite thermal velocity target effects on electron lifetimes without simultaneously treating the contribution to the observed X-ray spectrum from thermal electrons. We present model calculations of the X-ray spectra resulting from injection of a power-law energy distribution of electrons into a source with finite temperature. Reducing the power-law distribution low-energy cutoff to lower and lower energies only increases the relative magnitude of the thermal component of the spectrum, because the lowest energy electrons simply join the background thermal distributio...

  20. Towards tabletop production of intense quasimonochromatic X-ray beams using small 2-20 MeV accelerators

    Science.gov (United States)

    Avakian, Robert O.; Ispirian, Karo A.

    2005-08-01

    The existing synchrotron radiation sources and the fourth generation x-ray sources, which are projected at SLAC, USA, and DESY, Germany, are very expensive. For this reason the search for the novel and cheaper sources using various types of radiation produced by 2-20 MeV electrons available at many hospitals, universities and firms in various countries is of great interest. A review of the physics, history, new theoretical and experimental results and of some applications is given with a purpose to consider the possibilities of construction of small tabletop sources of quasimonochromatic X-ray photon beams necessary for scientific, industrial, medicine and other applications.

  1. Kinetic simulation of the electron-cyclotron maser instability: effect of a finite source size

    CERN Document Server

    Kuznetsov, A A

    2012-01-01

    The electron-cyclotron maser instability is widespread in the Universe, producing, e.g., radio emission of the magnetized planets and cool substellar objects. Diagnosing the parameters of astrophysical radio sources requires comprehensive nonlinear simulations of the radiation process. We simulate the electron-cyclotron maser instability in a very low-beta plasma. The model used takes into account the radiation escape from the source region and the particle flow through this region. We developed a kinetic code to simulate the time evolution of an electron distribution in a radio emission source. The model includes the terms describing the particle injection to and escape from the emission source region. The spatial escape of the emission from the source is taken into account by using a finite amplification time. The unstable electron distribution of the horseshoe type is considered. A number of simulations were performed for different parameter sets typical of the magnetospheres of planets and ultracool dwarf...

  2. Development of monoenergetic electron beam sources for radiation-instrument calibration

    Science.gov (United States)

    Soares, C. G.; Dick, C. E.; Pruitt, J. S.; Sparrow, J. H.

    1985-05-01

    Accelerator-produced electron beams are being studied for use in obtaining the response of beta-particle dosimetry instrumenta- tion as a function of electron energy. The NBS 4 MV Van de Graaff and 500 kV cascaded rectifier accelerators are being used to generate electron beams from 200 keV to 2.5 MeV. A device capable of scanning the electron beam in two dimensions over an area large enough to cover radiation-survey instruments uniformly is attached to the beam-handling system of each accelerator. The scanned beam exits from vacuum through a 16 cm 2 window consisting of either 25 μm Kapton (for energies below 500 keV) or 100 μm aluminum. The electron beams produced have been characterized in terms of (1) spatial distribution, (2) energy spectrum, and (3) absorbed dose to plastic. Spatial distributions were determined using film, while spectra were measured using a 5 mm-deep Si surface barrier detector. An extrapolation chamber is being used for beam standardization in terms of absorbed dose to plastic.

  3. Development of monoenergetic electron beam sources for radiation-instrument calibration

    Energy Technology Data Exchange (ETDEWEB)

    Soares, C.G.; Dick, C.E.; Pruitt, J.S.; Sparrow, J.H.

    1985-05-15

    Accelerator-produced electron beams are being studied for use in obtaining the response of beta-particle dosimetry instrumentation as a function of electron energy. The NBS 4 MV Van de Graaff and 500 kV cascaded rectifier accelerators are being used to generate electron beams from 200 keV to 2.5 MeV. A device capable of scanning the electron beam in two dimensions over an area large enough to cover radiation-survey instruments uniformly is attached to the beam-handling system of each accelerator. The scanned beam exits from vacuum through a 16 cm/sup 2/ window consisting of either 25 ..mu..m Kapton (for energies below 500 keV) or 100 ..mu..m aluminum. The electron beams produced have been characterized in terms of (1) spatial distribution, (2) energy spectrum, and (3) absorbed dose to plastic. Spatial distributions were determined using film, while spectra were measured using a 5 mm-deep Si surface barrier detector. An extrapolation chamber is being used for beam standardization in terms of absorbed dose to plastic. (orig.).

  4. Electronic sputtering of LiF, CaF2, LaF3 and UF4 with 197 MeV Au ions. Is the stoichiometry of atom emission preserved?

    Science.gov (United States)

    Toulemonde, M.; Assmann, W.; Muller, D.; Trautmann, C.

    2017-09-01

    Sputtering experiments with swift heavy ions in the electronic energy loss regime were performed by using the catcher technique in combination with elastic recoil detection analysis. Four different fluoride targets, LiF, CaF2, LaF3 and UF4 were irradiated in the electronic energy loss regime using 197 MeV Au ions. The angular distribution of particles sputtered from the surface of freshly cleaved LiF and CaF2 single crystals is composed of a broad cosine distribution superimposed by a jet-like peak that appears perpendicular to the surface independent of the angle of beam incidence. For LiF, the particle emission in the entire angular distribution (jet plus broad cosine component) is stoichiometric, whereas for CaF2 the ratio of the sputtered F to Ca particles is at large angles by a factor of two smaller than the stoichiometry of the crystal. For single crystalline LaF3 no jet component is observed and the angular distribution is non-stoichiometric with the number of sputtered F particles being slightly larger than the number of sputtered La particles. In the case of UF4, the target was polycrystalline and had a much rougher surface compared to cleaved crystals. This destroys the appearance of a possible jet component leading to a broad angular distribution. The ratio of sputtered U atoms compared to F atoms is in the order of 1-2, i.e. the number of collected particles on the catcher is also non-stoichiometric. Such unlike behavior of particles sputtered from different fluoride crystals creates new questions.

  5. Stimulated Raman Adiabatic Passage for Improved Performance of a Cold Atom Electron and Ion Source

    CERN Document Server

    Sparkes, B M; Taylor, R J; Spiers, R W; McCulloch, A J; Scholten, R E

    2016-01-01

    We experimentally implement high-efficiency coherent excitation to a Rydberg state using stimulated Raman adiabatic passage in a cold atom electron and ion source, leading to a peak efficiency of 85%, a 1.7 times improvement in excitation probability relative to incoherent pulsed-laser excitation. Using streak measurements and pulsed electric field ionization of the Rydberg atoms we demonstrate electron bunches with duration of 250 ps. High-efficiency excitation will increase source brightness, crucial for ultrafast electron diffraction experiments, while using coherent excitation to high-lying Rydberg states could allow for the reduction of internal bunch heating and the creation of a high-speed single ion source.

  6. Laser-based X-ray and electron source for X-ray fluorescence studies

    Science.gov (United States)

    Valle Brozas, F.; Crego, A.; Roso, L.; Peralta Conde, A.

    2016-08-01

    In this work, we present a modification to conventional X-rays fluorescence using electrons as excitation source and compare it with the traditional X-ray excitation for the study of pigments. For this purpose, we have constructed a laser-based source capable to produce X-rays as well as electrons. Because of the large penetration depth of X-rays, the collected fluorescence signal is a combination of several material layers of the artwork under study. However, electrons are stopped in the first layers, allowing a more superficial analysis. We show that the combination of both excitation sources can provide extremely valuable information about the structure of the artwork.

  7. High efficiency noble gas electron impact ion source for isotope separation

    Energy Technology Data Exchange (ETDEWEB)

    Appelhans, A. D. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Olson, J. E. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Dahl, D. A. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Ward, M. B. [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2016-07-01

    An electron impact ion source has been designed for generation of noble gas ions in a compact isotope separator. The source utilizes a circular filament that surrounds an ionization chamber, enabling multiple passes of electrons through the ionization chamber. This report presents ion optical design and the results of efficiency and sensitivity measurements performed in an ion source test chamber and in the compact isotope separator. The cylindrical design produced xenon ions at an efficiency of 0.37% with a sensitivity of ~24 µA /Pa at 300 µA of electron current.

  8. Investigation of multi-charged heavy ion production in an electron beam ion source

    Energy Technology Data Exchange (ETDEWEB)

    Hamm, R.W.

    1977-12-01

    Measurements of multi-charged heavy ions produced in an Electron Beam Ion Source (EBIS) were carried out with a test model ion source 20 cm in length. This test model utilized an electron gun placed external to the bore of the focusing solenoid in order to achieve electrostatically focussed electron beams and isolation of the vacuum surrounding the electron gun from the vacuum in the ionization region within the solenoid bore. An ultrahigh vacuum system utilizing liquid nitrogen (77/sup 0/K) cryopumping was used to achieve the low pressures needed in the ionization region for the operation of this ion source. Several technical problems limited the operation of this test model and prevented a thorough investigation of the ionization processes in the ion source, but the experimental results have shown qualitative agreement with the theoretical calculations for the operation of this type of ion source. Even with the problems of an insufficient vacuum and electron beam focussing field, measurable currents of C/sup +5/ and A/sup +8/ ions were produced. The present experimental results suggest that the approach taken in this work of using an external electron gun and cryopumping in the EBIS to achieve the large electron beam current density and low vacuum necessary for successful operation is a viable one. Such an ion source can be used to create highly-charged heavy ions for injection into a cyclotron or other type of particle accelerator.

  9. Carbon Nanotube Electron Sources: From Electron Beams to Energy Conversion and Optophononics

    OpenAIRE

    Alireza Nojeh

    2014-01-01

    Carbon nanotubes have a host of properties that make them excellent candidates for electron emitters. A significant amount of research has been conducted on nanotube-based field-emitters over the past two decades, and they have been investigated for devices ranging from flat-panel displays to vacuum tubes and electron microscopes. Other electron emission mechanisms from carbon nanotubes, such as photoemission, secondary emission, and thermionic emission, have also been studied, although to a ...

  10. Femtosecond Electron Diffraction: Next generation electron sources for atomically resolved dynamics

    OpenAIRE

    Hirscht, Julian

    2015-01-01

    Three instruments for femtosecond electron diffraction (FED) experiments were erected, partially commissioned and used for first diffraction experiments. The Relativistic Electron Gun for Atomic Exploration (REGAE) was completed by beamline elements including supports, a specimen chamber and dark current or electron beam collimating elements such that the commissioning process, including first diffraction experiments in this context, could be started. The temporal resolution of this machine i...

  11. Electron-helium and electron-neon scattering cross sections at low electron energies using a photoelectron source

    Science.gov (United States)

    Kumar, Vijay; Subramanian, K. P.; Krishnakumar, E.

    1987-01-01

    Absolute electron-helium and electron-neon scattering cross sections have been measured at low electron energies using the powerful technique of photoelectron spectroscopy. The measurements have been carried out at 17 electron energies varying from 0.7 to 10 eV with an accuracy of + or - 2.7 percent. The results obtained in the present work have been compared with other recent measurement and calculations.

  12. Auroral electron distributions within and close to the Saturn kilometric radiation source region

    Science.gov (United States)

    Schippers, P.; Arridge, C. S.; Menietti, J. D.; Gurnett, D. A.; Lamy, L.; Cecconi, B.; Mitchell, D. G.; André, N.; Kurth, W. S.; Grimald, S.; Dougherty, M. K.; Coates, A. J.; Krupp, N.; Young, D. T.

    2011-05-01

    On 17 October 2008, Cassini observed for the first time the electron populations associated with the crossing of a Saturn kilometric radiation source region and its surroundings. These observations allow for the first time the constraint and quantification of the high-latitude acceleration processes, the current systems, and the origin of the low-frequency electromagnetic waves. Enhanced fluxes of field-aligned energetic electrons were measured by the Cassini electron plasma spectrometer in conjunction with unusual intense field-aligned current systems identified using the magnetometer instrument. In the region where downward field-aligned currents were measured, electron data show evidence of two types of upward accelerated electron beams: a broadband energetic (1-100 keV) electron population that is observed throughout the region and a narrow-banded (0.1-1 keV) electron population that is observed sporadically. In the regions where the magnetic field signatures showed evidence for upward field-aligned currents, we observe electron loss cone distributions and some evidence of shell-like distributions. Such nonthermal electron populations are commonly known as a potential free energy source to drive plasma instabilities. In the downward current region, the low-energy and energetic beams are likely the source of the very low frequency emissions. In the upward current region, the shell distribution is identified as a potential source for Saturn kilometric radiation generation via the cyclotron maser instability.

  13. Chemical Ionization Mass Spectrometry Using Carbon Nanotube Field Emission Electron Sources

    Science.gov (United States)

    Radauscher, Erich J.; Keil, Adam D.; Wells, Mitch; Amsden, Jason J.; Piascik, Jeffrey R.; Parker, Charles B.; Stoner, Brian R.; Glass, Jeffrey T.

    2015-11-01

    A novel chemical ionization (CI) source has been developed based on a carbon nanotube (CNT) field emission electron source. The CNT-based electron source was evaluated and compared with a standard filament thermionic electron source in a commercial explosives trace detection desktop mass spectrometer. This work demonstrates the first reported use of a CNT-based ion source capable of collecting CI mass spectra. Both positive and negative modes were investigated. Spectra were collected for a standard mass spectrometer calibration compound, perfluorotributylamine (PFTBA), as well as trace explosives including trinitrotoluene (TNT), Research Department explosive (RDX), and pentaerythritol tetranitrate (PETN). The electrical characteristics, lifetime at operating pressure, and power requirements of the CNT-based electron source are reported. The CNT field emission electron sources demonstrated an average lifetime of 320 h when operated in constant emission mode under elevated CI pressures. The ability of the CNT field emission source to cycle on and off can provide enhanced lifetime and reduced power consumption without sacrificing performance and detection capabilities.

  14. Dosimetry calculations for internal electron sources using a Korean reference adult stylised phantom.

    Science.gov (United States)

    Park, S; Lee, J K; Lee, C; Lee, C

    2008-01-01

    Absorbed fractions (AFs) and specific absorbed fractions (SAFs) for internally deposited electron were calculated using a Korean reference adult stylised phantom, where a total of 15 internal organ volumes and external body dimension were designed to match average Korean adult male. The walls of oesophagus, stomach, colon and urinary bladder were additionally divided into the mucosal layer and residual wall to accommodate dose calculation for weakly penetrating electron. The mucosal wall thicknesses were determined by the data reported in the International Commission on Radiological Protection Publication 89 and other literature resources and by direct measurements. The Monte Carlo transport code MCNPX (version 2.5.0) was employed to calculate the electron energy deposited. The SAFs and AFs for monoenergetic electrons with the energies ranging from 10 keV to 2 MeV were calculated. The results were compared with those of the revised Oak Ridge National Laboratory phantoms and showed considerable differences up to 150% in SAFs, whereas no substantial differences were observed in the AFs.

  15. Experimental study on the activation process of GaAs spin—polarized electron source

    Institute of Scientific and Technical Information of China (English)

    RuanCun-Jun

    2003-01-01

    GaAs spin-polarized electron source is a new kind of electron source, where the GaAs semiconductor crystal is used as a photocathode under the irradiation of helicity light. In this paper the activation process of the GaAs spin-polarized electron source is unvestigated experimentally in detail, during which the negative electron affinity of the photo cathode should be achieved more carefully by absorbing the caesium and oxygen on the surface of the GaAs crystal under ultrahigh vacuum conditions. Besides the different activation processes, the important physical parameters are studied to achieve the optimum activation results. At the same time the stability and lifetime of the polarized electron beam are explored for future experiments. Some important experimental data have been acquired.

  16. Experimental study on the activation process of GaAs spin-polarized electron source

    Institute of Scientific and Technical Information of China (English)

    阮存军

    2003-01-01

    GaAs spin-polarized electron source is a new kind of electron source, where the GaAs semiconductor crystal is used as a photocathode under the irradiation of helicity light. In this paper the activation process of the GaAs spin-polarized electron source is investigated experimentally in detail, during which the negative electron affinity of the photo cathode should be achieved more carefully by absorbing the caesium and oxygen on the surface of the GaAs crystal under ultrahigh vacuum conditions. Besides the different activation processes, the important physical parameters are studied to achieve the optimum activation results. At the same time the stability and lifetime of the polarized electron beam are explored for future experiments. Some important experimental data have been acquired.

  17. Beam electrons as a source of Hα flare ribbons

    Science.gov (United States)

    Druett, Malcolm; Scullion, Eamon; Zharkova, Valentina; Matthews, Sarah; Zharkov, Sergei; Rouppe van der Voort, Luc

    2017-06-01

    The observations of solar flare onsets show rapid increase of hard and soft X-rays, ultra-violet emission with large Doppler blue shifts associated with plasma upflows, and Hα hydrogen emission with red shifts up to 1-4 Å. Modern radiative hydrodynamic models account well for blue-shifted emission, but struggle to reproduce closely the red-shifted Hα lines. Here we present a joint hydrodynamic and radiative model showing that during the first seconds of beam injection the effects caused by beam electrons can reproduce Hα line profiles with large red-shifts closely matching those observed in a C1.5 flare by the Swedish Solar Telescope. The model also accounts closely for timing and magnitude of upward motion to the corona observed 29 s after the event onset in 171 Å by the Atmospheric Imaging Assembly/Solar Dynamics Observatory.

  18. Electron pair creation by photons

    NARCIS (Netherlands)

    Holtwijk, Theodoor

    1960-01-01

    In our experiment on the creation of electron pairs a 5 MeV betatron was used as radiation source and a cloud chamber (with magnetic field) was used as detection instrument. The experimental arrangement is described in section 2.1. The cloud chamber was of the overcompression type so that the recove

  19. Electron pair creation by photons

    NARCIS (Netherlands)

    Holtwijk, Theodoor

    1960-01-01

    In our experiment on the creation of electron pairs a 5 MeV betatron was used as radiation source and a cloud chamber (with magnetic field) was used as detection instrument. The experimental arrangement is described in section 2.1. The cloud chamber was of the overcompression type so that the recove

  20. 1MeV电子加速器辐照剂量的测量%The Radiation Dosage of Electron Accelerator with the Energy at 1 MeV

    Institute of Scientific and Technical Information of China (English)

    杜纪富; 姜灿; 王升; 陈思; 李月生

    2014-01-01

    There were many methods to measure the absorbed dosage ,while due to the effect of low pene-trating depth ,thermal effects ,dynamic processing ,and other factors few methods were available to measure the radiation dosage of electron irradiation with low energy ,the color film dosimeter was usually used to mea-sure .In this paper ,the radio chromic film dosimeter (FWT-60-00 thin films) was used to measure the dose of low energy electron beam at the energy of 1 MeV used for irradiation processing .The relation between the ra-diation dosage and the beam intensity ,irradiation time and the speed of the beam device was investigated ,and the depth distribution of irradiation dose was measured ,the energy of the accelerator was corrected .The re-sults showed that ,with the same time and the electron energy ,the absorbed dose was grown linearly with the beam ;the dosage and the speed of beam device showed a good linear relationship at high speed .%目前吸收剂量的测量方法有多种,对低能电子束吸收剂量进行测量时,由于受到电子束穿透深度、热效应、动态加工等因素的影响,可用方法很少,通常用显色薄膜剂量片进行测量。本文采用FW T-60-00薄膜显色剂量片测量1 M eV 低能电子束进行辐照加工时的吸收剂量,研究了吸收剂量与束流强度、辐照时间、束下装置运行速度的关系,测量了材料中吸收剂量的深度分布,并对加速器能量进行了校正。结果表明:在相同的辐照时间和电子能量下,吸收剂量随束流的增加线性增长;速度较高时,吸收剂量与小车速度也呈现出良好的线性关系。

  1. Electron density and temperature in NIO1 RF source operated in oxygen and argon

    Science.gov (United States)

    Barbisan, M.; Zaniol, B.; Cavenago, M.; Pasqualotto, R.; Serianni, G.; Zanini, M.

    2017-08-01

    The NIO1 experiment, built and operated at Consorzio RFX, hosts an RF negative ion source, from which it is possible to produce a beam of maximum 130 mA in H- ions, accelerated up to 60 kV. For the preliminary tests of the extraction system the source has been operated in oxygen, whose high electronegativity allows to reach useful levels of extracted beam current. The efficiency of negative ions extraction is strongly influenced by the electron density and temperature close to the Plasma Grid, i.e. the grid of the acceleration system which faces the source. To support the tests, these parameters have been measured by means of the Optical Emission Spectroscopy diagnostic. This technique has involved the use of an oxygen-argon mixture to produce the plasma in the source. The intensities of specific Ar I and Ar II lines have been measured along lines of sight close to the Plasma Grid, and have been interpreted with the ADAS package to get the desired information. This work will describe the diagnostic hardware, the analysis method and the measured values of electron density and temperature, as function of the main source parameters (RF power, pressure, bias voltage and magnetic filter field). The main results show that not only electron density but also electron temperature increase with RF power; both decrease with increasing magnetic filter field. Variations of source pressure and plasma grid bias voltage appear to affect only electron temperature and electron density, respectively.

  2. Electron energy distributions and electron impact source functions in Ar/N{sub 2} inductively coupled plasmas using pulsed power

    Energy Technology Data Exchange (ETDEWEB)

    Logue, Michael D., E-mail: mdlogue@umich.edu; Kushner, Mark J., E-mail: mjkush@umich.edu [Department of Electrical Engineering and Computer Science, University of Michigan, 1301 Beal Ave., Ann Arbor, Michigan 48109-2122 (United States)

    2015-01-28

    In plasma materials processing, such as plasma etching, control of the time-averaged electron energy distributions (EEDs) in the plasma allows for control of the time-averaged electron impact source functions of reactive species in the plasma and their fluxes to surfaces. One potential method for refining the control of EEDs is through the use of pulsed power. Inductively coupled plasmas (ICPs) are attractive for using pulsed power in this manner because the EEDs are dominantly controlled by the ICP power as opposed to the bias power applied to the substrate. In this paper, we discuss results from a computational investigation of EEDs and electron impact source functions in low pressure (5–50 mTorr) ICPs sustained in Ar/N{sub 2} for various duty cycles. We find there is an ability to control EEDs, and thus source functions, by pulsing the ICP power, with the greatest variability of the EEDs located within the skin depth of the electromagnetic field. The transit time of hot electrons produced in the skin depth at the onset of pulse power produces a delay in the response of the EEDs as a function of distance from the coils. The choice of ICP pressure has a large impact on the dynamics of the EEDs, whereas duty cycle has a small influence on time-averaged EEDs and source functions.

  3. Design of a high-bunch-charge 112-MHz superconducting RF photoemission electron source

    Science.gov (United States)

    Xin, T.; Brutus, J. C.; Belomestnykh, Sergey A.; Ben-Zvi, I.; Boulware, C. H.; Grimm, T. L.; Hayes, T.; Litvinenko, Vladimir N.; Mernick, K.; Narayan, G.; Orfin, P.; Pinayev, I.; Rao, T.; Severino, F.; Skaritka, J.; Smith, K.; Than, R.; Tuozzolo, J.; Wang, E.; Xiao, B.; Xie, H.; Zaltsman, A.

    2016-09-01

    High-bunch-charge photoemission electron-sources operating in a continuous wave (CW) mode are required for many advanced applications of particle accelerators, such as electron coolers for hadron beams, electron-ion colliders, and free-electron lasers. Superconducting RF (SRF) has several advantages over other electron-gun technologies in CW mode as it offers higher acceleration rate and potentially can generate higher bunch charges and average beam currents. A 112 MHz SRF electron photoinjector (gun) was developed at Brookhaven National Laboratory to produce high-brightness and high-bunch-charge bunches for the coherent electron cooling proof-of-principle experiment. The gun utilizes a quarter-wave resonator geometry for assuring beam dynamics and uses high quantum efficiency multi-alkali photocathodes for generating electrons.

  4. Design of a High-bunch-charge 112-MHz Superconducting RF Photoemission Electron Source

    CERN Document Server

    Xin, T; Belomestnykh, Sergey A; Ben-Zvi, I; Boulware, C H; Grimm, T L; Hayes, T; Litvinenko, Vladimir N; Mernick, K; Narayan, G; Orfin, P; Pinayev, I; Rao, T; Severino, F; Skaritka, J; Smith, K; Than, R; Tuozzolo, J; Wang, E; Xiao, B; Xie, H; Zaltsman, A

    2016-01-01

    High-bunch-charge photoemission electron-sources operating in a continuous wave (CW) mode are required for many advanced applications of particle accelerators, such as electron coolers for hadron beams, electron-ion colliders, and free-electron lasers (FELs). Superconducting RF (SRF) has several advantages over other electron-gun technologies in CW mode as it offers higher acceleration rate and potentially can generate higher bunch charges and average beam currents. A 112 MHz SRF electron photoinjector (gun) was developed at Brookhaven National Laboratory (BNL) to produce high-brightness and high-bunch-charge bunches for the Coherent electron Cooling Proof-of-Principle (CeC PoP) experiment. The gun utilizes a quarter-wave resonator (QWR) geometry for assuring beam dynamics, and uses high quantum efficiency (QE) multi-alkali photocathodes for generating electrons.

  5. An Investigation into Electronic-Source Plagiarism in a First-Year Essay Assignment

    Science.gov (United States)

    Ellery, Karen

    2008-01-01

    Since the emergence of the electronic era, plagiarism has become an increasingly prevalent problem at tertiary institutions. This study investigated the role electronic sources of information played in influencing plagiarism in an essay assignment in a first-year geography module at the University of KwaZulu-Natal in South Africa. Despite explicit…

  6. High Energy Cosmic Electrons: Messengers from Nearby Cosmic Ray Sources or Dark Matter?

    Science.gov (United States)

    Moiseev, Alexander

    2011-01-01

    This slide presentation reviews the recent discoveries by the Large Area Telescope (LAT) and the Gamma-ray Burst Monitor (GBM) on board the Fermi Gamma-Ray Telescope in reference to high energy cosmic electrons, and whether their source is cosmic rays or dark matter. Specific interest is devoted to Cosmic Ray electrons anisotropy,

  7. Radiofrequency and 2.45 GHz electron cyclotron resonance H- volume production ion sources

    Science.gov (United States)

    Tarvainen, O.; Peng, S. X.

    2016-10-01

    The volume production of negative hydrogen ions ({{{H}}}-) in plasma ion sources is based on dissociative electron attachment (DEA) to rovibrationally excited hydrogen molecules (H2), which is a two-step process requiring both, hot electrons for ionization, and vibrational excitation of the H2 and cold electrons for the {{{H}}}- formation through DEA. Traditionally {{{H}}}- ion sources relying on the volume production have been tandem-type arc discharge sources equipped with biased filament cathodes sustaining the plasma by thermionic electron emission and with a magnetic filter separating the main discharge from the {{{H}}}- formation volume. The main motivation to develop ion sources based on radiofrequency (RF) or electron cyclotron resonance (ECR) plasma discharges is to eliminate the apparent limitation of the cathode lifetime. In this paper we summarize the principles of {{{H}}}- volume production dictating the ion source design and highlight the differences between the arc discharge and RF/ECR ion sources from both, physics and technology point-of-view. Furthermore, we introduce the state-of-the-art RF and ECR {{{H}}}- volume production ion sources and review the challenges and future prospects of these yet developing technologies.

  8. Prompt enhancement of the Earth's outer radiation belt due to substorm electron injections

    Science.gov (United States)

    Tang, C. L.; Zhang, J.-C.; Reeves, G. D.; Su, Z. P.; Baker, D. N.; Spence, H. E.; Funsten, H. O.; Blake, J. B.; Wygant, J. R.

    2016-12-01

    We present multipoint simultaneous observations of the near-Earth magnetotail and outer radiation belt during the substorm electron injection event on 16 August 2013. Time History of Events and Macroscale Interactions during Substorms A in the near-Earth magnetotail observed flux-enhanced electrons of 300 keV during the magnetic field dipolarization. Geosynchronous orbit satellites also observed the intensive electron injections. Located in the outer radiation belt, RBSP-A observed enhancements of MeV electrons accompanied by substorm dipolarization. The phase space density (PSD) of MeV electrons at L* 5.4 increased by 1 order of magnitude in 1 h, resulting in a local PSD peak of MeV electrons, which was caused by the direct effect of substorm injections. Enhanced MeV electrons in the heart of the outer radiation belt were also detected within 2 h, which may be associated with intensive substorm electron injections and subsequent local acceleration by chorus waves. Multipoint observations have shown that substorm electron injections not only can be the external source of MeV electrons at the outer edge of the outer radiation belt (L* 5.4) but also can provide the intensive seed populations in the outer radiation belt. These initial higher-energy electrons from injection can reach relativistic energy much faster. The observations also provide evidence that enhanced substorm electron injections can explain rapid enhancements of MeV electrons in the outer radiation belt.

  9. RF Phase Stability and Electron Beam Characterization for the PLEIADES Thomson X-Ray Source

    Energy Technology Data Exchange (ETDEWEB)

    Brown, W J; Hartemann, F V; Tremaine, A M; Springer, P T; Le Sage, G P; Barty, C P J; Rosenzweig, J B; Crane, J K; Cross, R R; Fittinghoff, D N; Gibson, D J; Slaughter, D R; Anderson, S

    2002-10-16

    We report on the performance of an S-band RF photocathode electron gun and accelerator for operation with the PLEIADES Thomson x-ray source at LLNL. To produce picosecond, high brightness x-ray pulses, picosecond timing, terahertz bandwidth diagnostics, and RF phase control are required. Planned optical, RF, x-ray and electron beam measurements to characterize the dependence of electron beam parameters and synchronization on RF phase stability are presented.

  10. ELECTRON-CAPTURE SUPERNOVAE AS SOURCES OF {sup 60}Fe

    Energy Technology Data Exchange (ETDEWEB)

    Wanajo, Shinya [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Janka, Hans-Thomas; Mueller, Bernhard, E-mail: shinya.wanajo@nao.ac.jp [Max-Planck-Institut fuer Astrophysik, Karl-Schwarzschild-Str. 1, D-85748 Garching (Germany)

    2013-09-01

    We investigate the nucleosynthesis of the radionuclide {sup 60}Fe in electron-capture supernovae (ECSNe). The nucleosynthetic results are based on a self-consistent, two-dimensional simulation of an ECSN as well as models in which the densities are systematically increased by some factors (low-entropy models). {sup 60}Fe is found to be appreciably made in neutron-rich ejecta during the nuclear quasi-equilibrium phase with greater amounts being produced in the lower-entropy models. Our results, combining them with the yields of core-collapse supernovae in the literature, suggest that ECSNe account for at least 4%-30% of live {sup 60}Fe in the Milky Way. ECSNe co-produce neutron-rich isotopes, {sup 48}Ca, {sup 50}Ti, {sup 54}Cr, some light trans-iron elements, and possibly weak r-process elements including some radionuclides such as {sup 93}Zr, {sup 99}Tc, and {sup 107}Pd, whose association with {sup 60}Fe might have been imprinted in primitive meteorites or in the deep ocean crust on the Earth.

  11. Techniques and mechanisms applied in electron cyclotron resonance sources for highly charged ions

    NARCIS (Netherlands)

    Drentje, AG

    2003-01-01

    Electron cyclotron resonance ion sources are delivering beams of highly charged ions for a wide range of applications in many laboratories. For more than two decades, the development of these ion sources has been to a large extent an intuitive and experimental enterprise. Much effort has been spent

  12. Electron-based EUV and ultrashort hard-x-ray sources

    Science.gov (United States)

    Egbert, A.; Mader, B.; Tkachenko, B.; Chichkov, B. N.

    2002-11-01

    A brief review of our progress in the realization of femtosecond laser-driven ultrashort hard-x-ray sources is given. New results on the development of electron-based compact EUV sources for "at-wavelength" metrology and next generation lithography are presented. AIP Conference Proceedings.

  13. Evaluating Open Source Software for Use in Library Initiatives: A Case Study Involving Electronic Publishing

    Science.gov (United States)

    Samuels, Ruth Gallegos; Griffy, Henry

    2012-01-01

    This article discusses best practices for evaluating open source software for use in library projects, based on the authors' experience evaluating electronic publishing solutions. First, it presents a brief review of the literature, emphasizing the need to evaluate open source solutions carefully in order to minimize Total Cost of Ownership. Next,…

  14. Radioactive source control and electronics for the ATLAS tile calorimeter cesium calibration system

    CERN Document Server

    Shalanda, N A; Kopikov, S; Shalimov, A; Soldatov, M; Solodkov, A; Starchenko, E A

    2003-01-01

    A system using a radioactive /sup 137/Cs source to calibrate and monitor the Hadron Calorimeter (TileCal) of the ATLAS experiment at the LHC is described. The system includes a set of sensors to monitor the position of the source which moves via hydraulic propulsion. The design of the sensors, the corresponding electronic modules and their performance are detailed. (6 refs).

  15. Techniques and mechanisms applied in electron cyclotron resonance sources for highly charged ions

    NARCIS (Netherlands)

    Drentje, AG

    Electron cyclotron resonance ion sources are delivering beams of highly charged ions for a wide range of applications in many laboratories. For more than two decades, the development of these ion sources has been to a large extent an intuitive and experimental enterprise. Much effort has been spent

  16. Electron-suppression experiments in a small multicusp H sup minus source

    Energy Technology Data Exchange (ETDEWEB)

    Leung, K.N.; Hauck, C.A.; Kunkel, W.B.; Walther, S.R. (Accelerator Research Division Fusion Research Division, Lawrence Berkeley Laboratory, 1 Cyclotron Road, Berkeley, California 94720 (US))

    1990-03-01

    Several techniques for suppressing the electrons before they form part of the extracted beam have been studied in a small multicusp H{sup {minus}} source. It is found that some schemes reduce both the electron and the H{sup {minus}} output currents. Other approaches, such as the installation of a collar at the extraction aperture, the addition of xenon or cesium to the hydrogen discharge, or the reduction of the source plasma potential, not only can reduce the electron current substantially, but bring about an enhancement in the extracted H{sup {minus}} current.

  17. Investigation of the durability of a pyroelectric neutron source and secondary electron suppression

    Energy Technology Data Exchange (ETDEWEB)

    Friske, Eduard; Deuter, Gerhard; Jochum, Josef [Universitaet Tuebingen, Physikalisches Institut, Tuebingen (Germany)

    2015-04-15

    The performance of a pyroelectric neutron source depends on several factors, such as the achieved high voltage, deuterium gas pressure and the tip geometry. Here we present measurements to investigate the dependency of the neutron production on the high voltage specifically and discuss the interdependency with other factors. In addition we present results showing that a biased grid in front of the target, which is a common way to capture secondary electrons, does not have any significant effect on the amount of electrons streaming back to the pyroelectric crystal. This indicates that the bulk of these electrons does not originate from the target but from a different source. (orig.)

  18. Suppression of cyclotron instability in Electron Cyclotron Resonance ion sources by two-frequency heating

    Energy Technology Data Exchange (ETDEWEB)

    Skalyga, V. [Institute of Applied Physics of Russian Academy of Sciences, 46 Ulyanova st., Nizhny Novgorod (Russian Federation); Lobachevsky State University of Nizhny Novgorod (UNN), 23 Gagarina st., Nizhny Novgorod (Russian Federation); Izotov, I.; Mansfeld, D. [Institute of Applied Physics of Russian Academy of Sciences, 46 Ulyanova st., Nizhny Novgorod (Russian Federation); Kalvas, T.; Koivisto, H.; Komppula, J.; Kronholm, R.; Laulainen, J.; Tarvainen, O. [Department of Physics, University of Jyväskylä, Jyväskylä (Finland)

    2015-08-15

    Multiple frequency heating is one of the most effective techniques to improve the performance of Electron Cyclotron Resonance (ECR) ion sources. The method increases the beam current and average charge state of the extracted ions and enhances the temporal stability of the ion beams. It is demonstrated in this paper that the stabilizing effect of two-frequency heating is connected with the suppression of electron cyclotron instability. Experimental data show that the interaction between the secondary microwave radiation and the hot electron component of ECR ion source plasmas plays a crucial role in mitigation of the instabilities.

  19. Status of the 1 MeV Accelerator Design for ITER NBI

    Science.gov (United States)

    Kuriyama, M.; Boilson, D.; Hemsworth, R.; Svensson, L.; Graceffa, J.; Schunke, B.; Decamps, H.; Tanaka, M.; Bonicelli, T.; Masiello, A.; Bigi, M.; Chitarin, G.; Luchetta, A.; Marcuzzi, D.; Pasqualotto, R.; Pomaro, N.; Serianni, G.; Sonato, P.; Toigo, V.; Zaccaria, P.; Kraus, W.; Franzen, P.; Heinemann, B.; Inoue, T.; Watanabe, K.; Kashiwagi, M.; Taniguchi, M.; Tobari, H.; De Esch, H.

    2011-09-01

    The beam source of neutral beam heating/current drive system for ITER is needed to accelerate the negative ion beam of 40A with D- at 1 MeV for 3600 sec. In order to realize the beam source, design and R&D works are being developed in many institutions under the coordination of ITER organization. The development of the key issues of the ion source including source plasma uniformity, suppression of co-extracted electron in D beam operation and also after the long beam duration time of over a few 100 sec, is progressed mainly in IPP with the facilities of BATMAN, MANITU and RADI. In the near future, ELISE, that will be tested the half size of the ITER ion source, will start the operation in 2011, and then SPIDER, which demonstrates negative ion production and extraction with the same size and same structure as the ITER ion source, will start the operation in 2014 as part of the NBTF. The development of the accelerator is progressed mainly in JAEA with the MeV test facility, and also the computer simulation of beam optics also developed in JAEA, CEA and RFX. The full ITER heating and current drive beam performance will be demonstrated in MITICA, which will start operation in 2016 as part of the NBTF.

  20. New electron source concept for single-shot sub-100 fs electron diffraction in the 100 keV range

    CERN Document Server

    van Oudheusden, T; Siwick, B J; Van der Geer, S B; Root, W P E M O; Luiten, O J

    2007-01-01

    We present a method for producing sub-100 fs electron bunches that are suitable for single-shot ultrafast electron diffraction experiments in the 100 keV energy range. A combination of analytical results and state-of-the-art numerical simulations show that it is possible to create 100 keV, 0.1 pC, 20 fs electron bunches with a spotsize smaller than 500 micron and a transverse coherence length of 3 nm, using established technologies in a table-top set-up. The system operates in the space-charge dominated regime to produce energy-correlated bunches that are recompressed by established radio-frequency techniques. With this approach we overcome the Coulomb expansion of the bunch, providing an entirely new ultrafast electron diffraction source concept.

  1. Penelope simulation of electron beams 6 MeV from a linear accelerator for studies in different materials equivalent to human body; Simulacion Penelope de haces de electrones de 6 MeV de un acelerador lineal para estudios en diferentes materiales equivalentes al cuerpo humano

    Energy Technology Data Exchange (ETDEWEB)

    Apaza V, D.; Cardena R, R.; Cayllahua Q, F.; Vega R, J. [Universidad Nacional de San Agustin de Arequipa, Av. Independencia s/n, Hexagonos de Fisica, Arequipa (Peru); Urquizo B, R., E-mail: dgav02@gmail.com [Hospital Nacional Carlos Alberto Seguin Escobedo, Esquina de Peral y Filtro s/n, Arequipa (Peru)

    2015-10-15

    In systems of radiotherapy treatment for cancer, always looking to maximize the radiation dose on the target (tumor) and minimize to the organs at risk or healthy, so they resort to using electron beams that have properties and characteristics of higher dose deposition at fixed depths, directing and focusing the higher dose in the tumor, without harming healthy tissues to which seeks to radiate in the least possible. Simulating the interaction of electron beams with different equivalent tissues to the human body leads to a better dosimetric evaluation, improving the quality of treatment planning. The aim of this study is the comparison from the characterization of several equivalent tissues to the human body such as soft tissue, bone and lung. Based on the simulation of a calibration beam in water phantom with Penelope code and compared with the results of the calibration curves of beams in water vat by a linear accelerator Elekta Synergy of Hospital Nacional Carlos Alberto Seguin Escobedo EsSalud of Arequipa (Peru). From this to evaluate the behavior of electron beams in a homogeneous medium and then further evaluation in the human body homogeneities, for better evaluation and specific treatment planning. (Author)

  2. Design of a new electron cyclotron resonance ion source at Oshima National College of Maritime Technology

    Energy Technology Data Exchange (ETDEWEB)

    Asaji, T., E-mail: asaji@oshima-k.ac.jp; Hirabara, N.; Izumihara, T.; Nakamizu, T.; Ohba, T.; Nakamura, T.; Furuse, M. [Oshima National College of Maritime Technology (OCMT), 1091-1 Komatsu, Suo-oshima, Yamaguchi 742-2193 (Japan); Hitobo, T. [Tateyama Machine Co., Ltd., 30 Shimonoban, Toyama 930-1305 (Japan); Kato, Y. [Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871 (Japan)

    2014-02-15

    A new electron cyclotron resonance ion/plasma source has been designed and will be built at Oshima National College of Maritime Technology by early 2014. We have developed an ion source that allows the control of the plasma parameters over a wide range of electron temperatures for material research. A minimum-B magnetic field composed of axial mirror fields and radial cusp fields was designed using mainly Nd-Fe-B permanent magnets. The axial magnetic field can be varied by three solenoid coils. The apparatus has 2.45 GHz magnetron and 2.5–6.0 GHz solid-state microwave sources.

  3. Preparation of {sup 114m}In low energy conversion electron sources

    Energy Technology Data Exchange (ETDEWEB)

    Wrede, C., E-mail: wrede@uw.ed [Center for Experimental Nuclear Physics and Astrophysics, and Department of Physics, University of Washington, Seattle, WA 98195 (United States); Filippone, B.W. [Kellogg Radiation Laboratory, California Institute of Technology, Pasadena, California 91125 (United States); Garcia, A.; Harper, G.C. [Center for Experimental Nuclear Physics and Astrophysics, and Department of Physics, University of Washington, Seattle, WA 98195 (United States); Lassell, S. [Department of Nuclear Engineering, North Carolina State University, Raleigh, North Carolina 27695 (United States); Liu, J. [Kellogg Radiation Laboratory, California Institute of Technology, Pasadena, California 91125 (United States); Department of Physics, Shanghai Jiao Tong University, Shanghai 200240 (China); Mendenhall, M.P. [Kellogg Radiation Laboratory, California Institute of Technology, Pasadena, California 91125 (United States); Palmer, A.S.C. [Center for Experimental Nuclear Physics and Astrophysics, and Department of Physics, University of Washington, Seattle, WA 98195 (United States); Pattie, R.W. [Department of Physics, North Carolina State University, Raleigh, North Carolina 27695 (United States); Will, D.I. [Center for Experimental Nuclear Physics and Astrophysics, and Department of Physics, University of Washington, Seattle, WA 98195 (United States); Young, A.R. [Department of Physics, North Carolina State University, Raleigh, North Carolina 27695 (United States)

    2011-05-15

    Highlights: {yields} Controlled ion implantation of In-113 into thin Al substrate. {yields} Production of In-114m (half life = 50 days) by neutron irradiation. {yields} Use of In-114m as a source of electron lines and continuum for calibrations. {yields} Source reactivation by short neutron irradiation. -- Abstract: The preparation of {sup 114m}In sources of conversion electrons in the energy range 162-190 keV and {beta} continuum with a 1989 keV endpoint via ion implantation of {sup 113}In into Al substrates and subsequent irradiation by thermal and epi-thermal neutrons in a nuclear reactor is described.

  4. Contribution from individual nearby sources to the spectrum of high-energy cosmic-ray electrons

    Energy Technology Data Exchange (ETDEWEB)

    Sedrati, R., E-mail: rafik.sedrati@univ-annaba.org; Attallah, R.

    2014-04-01

    In the last few years, very important data on high-energy cosmic-ray electrons and positrons from high-precision space-born and ground-based experiments have attracted a great deal of interest. These particles represent a unique probe for studying local comic-ray accelerators because they lose energy very rapidly. These energy losses reduce the lifetime so drastically that high-energy cosmic-ray electrons can attain the Earth only from rather local astrophysical sources. This work aims at calculating, by means of Monte Carlo simulation, the contribution from some known nearby astrophysical sources to the cosmic-ray electron/positron spectra at high energy (≥10GeV). The background to the electron energy spectrum from distant sources is determined with the help of the GALPROP code. The obtained numerical results are compared with a set of experimental data.

  5. Production and ion-ion cooling of highly charged ions in electron string ion source.

    Science.gov (United States)

    Donets, D E; Donets, E D; Donets, E E; Salnikov, V V; Shutov, V B; Syresin, E M

    2009-06-01

    The scheme of an internal injection of Au atoms into the working space of the "Krion-2" electron string ion source (ESIS) was applied and tested. In this scheme Au atoms are evaporated from the thin tungsten wire surface in vicinity of the source electron string. Ion beams with charge states up to Au51+ were produced. Ion-ion cooling with use of C and O coolant ions was studied. It allowed increasing of the Au51+ ion yield by a factor of 2. Ions of Kr up to charge state 28+ were also produced in the source. Electron strings were first formed with injection electron energy up to 6 keV. Methods to increase the ESIS ion output are discussed.

  6. Strong Radiation-Damping Effects in a Gamma-Ray Source Generated by the Interaction of a High-Intensity Laser with a Wakefield-Accelerated Electron Beam

    Science.gov (United States)

    Thomas, A. G. R.; Ridgers, C. P.; Bulanov, S. S.; Griffin, B. J.; Mangles, S. P. D.

    2012-10-01

    A number of theoretical calculations have studied the effect of radiation-reaction forces on radiation distributions in strong-field counterpropagating electron-beam-laser interactions, but could these effects—including quantum corrections—be observed in interactions with realistic bunches and focusing fields, as is hoped in a number of soon-to-be-proposed experiments? We present numerical calculations of the angularly resolved radiation spectrum from an electron bunch with parameters similar to those produced in laser-wakefield-acceleration experiments, interacting with an intense, ultrashort laser pulse. For our parameters, the effect of radiation damping on the angular distribution and energy distribution of photons is not easily discernible for a realistic moderate-emittance electron beam. However, experiments using such a counterpropagating beam-laser geometry should be able to measure these effects using current laser systems through measurement of the electron-beam properties. In addition, the brilliance of this source is very high, with peak spectral brilliance exceeding 1029photonss-1mm-2mrad-2(0.1%bandwidth)-1 with an approximately 2% conversion efficiency and with a peak energy of 10 MeV.

  7. Measurements of the linac coherent light source laser heater and its impact on the x-ray free-electron laser performance

    Directory of Open Access Journals (Sweden)

    Z. Huang

    2010-02-01

    Full Text Available The very bright electron beam required for an x-ray free-electron laser (FEL, such as the linac coherent light source (LCLS, is susceptible to a microbunching instability in the magnetic bunch compressors, prior to the FEL undulator. The uncorrelated electron energy spread in the LCLS can be increased by an order of magnitude to provide strong Landau damping against the instability without degrading the FEL performance. To this end, a “laser-heater” system has been installed in the LCLS injector, which modulates the energy of a 135-MeV electron bunch with an IR-laser beam in a short undulator, enclosed within a four-dipole chicane. In this paper, we report detailed measurements of laser-heater-induced energy spread, including the unexpected self-heating phenomenon when the laser energy is very low. We discuss the suppression of the microbunching instability with the laser heater and its impact on the x-ray FEL performance. We also present the analysis of these experimental results and develop a three-dimensional longitudinal space charge model to explain the self-heating effect.

  8. Development of a high average current polarized electron source with long cathode operational lifetime

    Energy Technology Data Exchange (ETDEWEB)

    C. K. Sinclair; P. A. Adderley; B. M. Dunham; J. C. Hansknecht; P. Hartmann; M. Poelker; J. S. Price; P. M. Rutt; W. J. Schneider; M. Steigerwald

    2007-02-01

    Substantially more than half of the electromagnetic nuclear physics experiments conducted at the Continuous Electron Beam Accelerator Facility of the Thomas Jefferson National Accelerator Facility (Jefferson Laboratory) require highly polarized electron beams, often at high average current. Spin-polarized electrons are produced by photoemission from various GaAs-based semiconductor photocathodes, using circularly polarized laser light with photon energy slightly larger than the semiconductor band gap. The photocathodes are prepared by activation of the clean semiconductor surface to negative electron affinity using cesium and oxidation. Historically, in many laboratories worldwide, these photocathodes have had short operational lifetimes at high average current, and have often deteriorated fairly quickly in ultrahigh vacuum even without electron beam delivery. At Jefferson Lab, we have developed a polarized electron source in which the photocathodes degrade exceptionally slowly without electron emission, and in which ion back bombardment is the predominant mechanism limiting the operational lifetime of the cathodes during electron emission. We have reproducibly obtained cathode 1/e dark lifetimes over two years, and 1/e charge density and charge lifetimes during electron beam delivery of over 2?105???C/cm2 and 200 C, respectively. This source is able to support uninterrupted high average current polarized beam delivery to three experimental halls simultaneously for many months at a time. Many of the techniques we report here are directly applicable to the development of GaAs photoemission electron guns to deliver high average current, high brightness unpolarized beams.

  9. Simulation and optimization of a 10 A electron gun with electrostatic compression for the electron beam ion source.

    Science.gov (United States)

    Pikin, A; Beebe, E N; Raparia, D

    2013-03-01

    Increasing the current density of the electron beam in the ion trap of the Electron Beam Ion Source (EBIS) in BNL's Relativistic Heavy Ion Collider facility would confer several essential benefits. They include increasing the ions' charge states, and therefore, the ions' energy out of the Booster for NASA applications, reducing the influx of residual ions in the ion trap, lowering the average power load on the electron collector, and possibly also reducing the emittance of the extracted ion beam. Here, we discuss our findings from a computer simulation of an electron gun with electrostatic compression for electron current up to 10 A that can deliver a high-current-density electron beam for EBIS. The magnetic field in the cathode-anode gap is formed with a magnetic shield surrounding the gun electrodes and the residual magnetic field on the cathode is (5 ÷ 6) Gs. It was demonstrated that for optimized gun geometry within the electron beam current range of (0.5 ÷ 10) A the amplitude of radial beam oscillations can be maintained close to 4% of the beam radius by adjusting the injection magnetic field generated by a separate magnetic coil. Simulating the performance of the gun by varying geometrical parameters indicated that the original gun model is close to optimum and the requirements to the precision of positioning the gun elements can be easily met with conventional technology.

  10. Simulation and optimization of a 10 A electron gun with electrostatic compression for the electron beam ion source

    Energy Technology Data Exchange (ETDEWEB)

    Pikin, A.; Beebe, E. N.; Raparia, D. [Brookhaven National Laboratory, Upton, New York 11973 (United States)

    2013-03-15

    Increasing the current density of the electron beam in the ion trap of the Electron Beam Ion Source (EBIS) in BNL's Relativistic Heavy Ion Collider facility would confer several essential benefits. They include increasing the ions' charge states, and therefore, the ions' energy out of the Booster for NASA applications, reducing the influx of residual ions in the ion trap, lowering the average power load on the electron collector, and possibly also reducing the emittance of the extracted ion beam. Here, we discuss our findings from a computer simulation of an electron gun with electrostatic compression for electron current up to 10 A that can deliver a high-current-density electron beam for EBIS. The magnetic field in the cathode-anode gap is formed with a magnetic shield surrounding the gun electrodes and the residual magnetic field on the cathode is (5 Division-Sign 6) Gs. It was demonstrated that for optimized gun geometry within the electron beam current range of (0.5 Division-Sign 10) A the amplitude of radial beam oscillations can be maintained close to 4% of the beam radius by adjusting the injection magnetic field generated by a separate magnetic coil. Simulating the performance of the gun by varying geometrical parameters indicated that the original gun model is close to optimum and the requirements to the precision of positioning the gun elements can be easily met with conventional technology.

  11. Development of an ultrashort table-top electron and x-ray source pumped by laser

    Science.gov (United States)

    Girardeau-Montaut, Jean-Pierre; Kiraly, Bela; Girardeau-Montaut, Claire; Leboutet, Hubert

    1999-09-01

    We report on the design of the CIBER-X source which is a new laser driven table-top ultrashort electron and x-ray source. X-ray pulses are produced by a three-step process which consists of the electron pulse production from a thin metallic photocathode illuminated by picosecond 213 nm laser pulses with 16 ps duration. The electrons are accelerated in the diode by a cw electric field of 11 MV/m, and the photoinjector produces a single 70 - 100 keV electron pulse of approximately 0,5 nC and approximately 20 A peak current at a repetition rate of 10 Hz. The gun is a standard Pierce diode electrode type, the electrons leaving the diode through a hole made in the anode. The electrons are then transported along a path approximately 20 cm long, and are focused by two magnetic fields produced by electromagnetic coils. Finally, the x-rays are produced by the impact of electrons on a massive target of Tm. Simulations of geometrical and energetic characteristics of the complete source were done previously with assistance of the code PIXEL1. Finally, experimental performances of electron and x-ray bursts are discussed.

  12. Investigating the source of near-relativistic and relativistic electrons in Earth's inner radiation belt

    Science.gov (United States)

    Turner, D. L.; O'Brien, T. P.; Fennell, J. F.; Claudepierre, S. G.; Blake, J. B.; Jaynes, A. N.; Baker, D. N.; Kanekal, S.; Gkioulidou, M.; Henderson, M. G.; Reeves, G. D.

    2017-01-01

    Using observations from NASA's Van Allen Probes, we study the role of sudden particle enhancements at low L shells (SPELLS) as a source of inner radiation belt electrons. SPELLS events are characterized by electron intensity enhancements of approximately an order of magnitude or more in less than 1 day at L belt electrons under quiet/average conditions. During SPELLS events, the evolution of electron distributions reveals an enhancement of phase space density that can exceed 3 orders of magnitude in the slot region and continues into the inner radiation belt, which is evidence that these events are an important - and potentially dominant - source of inner belt electrons. Electron fluxes from September 2012 through February 2016 reveal that SPELLS occur frequently ( 2.5/month at 200 keV), but the number of observed events decreases exponentially with increasing electron energy for ≥100 keV. After SPELLS events, the slot region reforms due to slow energy-dependent decay over several day time scales, consistent with losses due to interactions with plasmaspheric hiss. Combined, these results indicate that the peaked phase space density distributions in the inner electron radiation belt result from an "on/off," geomagnetic-activity-dependent source from higher radial distances.

  13. A high-brightness, electron-based source of polarized photons and neutrons

    Science.gov (United States)

    Spencer, J. E.

    1999-06-01

    A compact and comparatively inexpensive system that is practical for universities is described based on a low-energy, electron storage ring with at least one undulator based oscillator to store photons. If the oscillator cavity length is relativistically corrected to be an harmonic of the ring circumference (LC=βLRn/nB with nB the number of bunches), higher-energy, secondary photons from Compton backscattering may become significant. Then, besides synchrotron radiation from the ring dipoles and damping wigglers as well as undulator photons, there are frequency upshifted Compton photons and photoneutrons from low Q-value targets such as Beryllium (Qn=-1.66) or Deuterium (Qn=-2.22 MeV). For 100 MeV electron bunches, an adjustable-phase, planar, helical undulator can be made to produce circularly polarized UV photons having a fundamental ɛγ1=11.1 eV. If these photons are stored in a multimode, hole-coupled resonator they produce a Compton endpoint energy up to ɛγ2=1.7 MeV. When incident on a Be conversion target these secondary photons make unmoderated, epithermal neutrons having mean energy ɛn=24.8±6.8 keV from the two-body reaction Be9+γ→n+Be8(→2α)with negligible, residual radioactivity. The system is shown in Fig. 1. When the target is unpolarized, one expects neutron rates of 1011 epithermal n/s for 1015 Comptons/s and a circulating current of 1 A with polarizations PRHC(n⃗)=-0.5, PLHC(n⃗)=0.5, both with reduced flux, and PLin(n⃗)=0. With a 1 cm thick cylindrical tungsten sheath surrounding the Be to attenuate scattered photons exiting at 90° to the incident photons, there is a peak neutron flux of ≈109 epithermal n/s/cm2 cylindrically symmetric around the surface. No attempt was made to optimize this because there is still no accepted treatment protocol (dose rates or preferred neutron energy distribution). Although these factors depend on the individual case, several thousand BNCT treatments per year appear feasible. A potential clinical

  14. Kinetic energy offsets for multicharged ions from an electron beam ion source.

    Science.gov (United States)

    Kulkarni, D D; Ahl, C D; Shore, A M; Miller, A J; Harriss, J E; Sosolik, C E; Marler, J P

    2017-08-01

    Using a retarding field analyzer, we have measured offsets between the nominal and measured kinetic energy of multicharged ions extracted from an electron beam ion source (EBIS). By varying source parameters, a shift in ion kinetic energy was attributed to the trapping potential produced by the space charge of the electron beam within the EBIS. The space charge of the electron beam depends on its charge density, which in turn depends on the amount of negative charge (electron beam current) and its velocity (electron beam energy). The electron beam current and electron beam energy were both varied to obtain electron beams of varying space charge and these were related to the observed kinetic energy offsets for Ar(4+) and Ar(8+) ion beams. Knowledge of these offsets is important for studies that seek to utilize slow, i.e., low kinetic energy, multicharged ions to exploit their high potential energies for processes such as surface modification. In addition, we show that these offsets can be utilized to estimate the effective radius of the electron beam inside the trap.

  15. Research on modeling of heat source for electron beam welding fusion-solidification zone

    Institute of Scientific and Technical Information of China (English)

    Wang Yajun; Fu Pengfei; Guan Yongjun; Lu Zhijun; Wei Yintao

    2013-01-01

    In this paper,the common heat source model of point and linear heat source in the numerical simulation of electron beam welding (EBW) were summarized and introduced.The combined point-linear heat source model was brought forward and to simulate the welding temperature fields of EBW and predicting the weld shape.The model parameters were put forward and regulated in the combined model,which included the ratio of point heat source to linear heat source Qpr and the distribution of linear heat source Lr.Based on the combined model,the welding temperature fields of EBW were investigated.The results show that the predicted weld shapes are conformable to those of the actual,the temperature fields are reasonable and correct by simulating with combined point-linear heat source model and the typical weld shapes are gained.

  16. Novel thin film field emission electron source laboratory directed research and development final report

    Energy Technology Data Exchange (ETDEWEB)

    Walko, R.J.; Fleming, J.G.; Hubbs, J.W.

    1997-04-01

    The objective of this project was to demonstrate proof of concept of a thin film field emission electron source based on electron tunneling between discrete metal islands on an insulating substrate. An electron source of this type should be more easily fabricated permitting the use of a wider range of materials, and be less prone to damage and erratic behavior than the patterned field emitter arrays currently under development for flat panel displays and other vacuum microelectronic applications. This report describes the results of the studies of electron and light emission from such structures, and the subsequent discovery of a source of light emission from conductive paths across thin insulating gaps of the semiconductor-insulator-semiconductor (SIS) and metal-insulator-semiconductor (MIS) structures. The substrates consisted of silicon nitride and silicon dioxide on silicon wafers, Kapton{reg_sign}, quartz, and cut slabs of silica aerogels. The conductive film samples were prepared by chemical vapor deposition (CVD) and sputtering, while the MIS and SIS samples were prepared by CVD followed by cleaving, grinding, mechanical indentation, erosion by a sputter Auger beam, electrical arcing and chemical etching. Electron emission measurements were conducted in high and ultra high vacuum systems at SNL, NM as well as at SNL, CA. Optical emission measurements were made in air under an optical microscope as well as in the above vacuum environments. Sample morphology was investigated using both scanning electron microscopy (SEM) and transmission electron microscopy (TEM).

  17. Making carbon nanotube electron sources of defined lengths and with closed caps.

    Science.gov (United States)

    Heeres, Erwin C; Oosterkamp, Tjerk H; de Jonge, Niels

    2011-06-10

    A method is reported to make an electron source consisting of an individual multi-walled carbon nanotube (MWNT) mounted on a tungsten support tip, and cut to length using localized electron beam irradiation in a scanning electron microscope. The apex of the MWNT was transformed into a closed cap with at least one fullerene-like layer via an annealing process involving simultaneous heating and the extraction of an emission current of ∼ 1 mA. The electron emission occurred at localized emission sites. The electron emission showed Fowler-Nordheim behavior, was highly stable with time, and exhibited a low energy spread. The structure of the caps of two MWNTs was studied with transmission electron microscopy before and after the cap closure.

  18. Low-kilovolt coherent electron diffractive imaging instrument based on a single-atom electron source

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Chun-Yueh [Department of Physics, National Taiwan University, Taipei 10617, Taiwan (China); Chang, Wei-Tse; Chen, Yi-Sheng; Hwu, En-Te; Chang, Chia-Seng; Hwang, Ing-Shouh, E-mail: ishwang@phys.sinica.edu.tw [Institute of Physics, Academia Sinica, Nankang, Taipei 11529, Taiwan (China); Hsu, Wei-Hao [Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan (China)

    2016-03-15

    In this work, a transmission-type, low-kilovolt coherent electron diffractive imaging instrument was constructed. It comprised a single-atom field emitter, a triple-element electrostatic lens, a sample holder, and a retractable delay line detector to record the diffraction patterns at different positions behind the sample. It was designed to image materials thinner than 3 nm. The authors analyzed the asymmetric triple-element electrostatic lens for focusing the electron beams and achieved a focused beam spot of 87 nm on the sample plane at the electron energy of 2 kV. High-angle coherent diffraction patterns of a suspended graphene sample corresponding to (0.62 Å){sup −1} were recorded. This work demonstrated the potential of coherent diffractive imaging of thin two-dimensional materials, biological molecules, and nano-objects at a voltage between 1 and 10 kV. The ultimate goal of this instrument is to achieve atomic resolution of these materials with high contrast and little radiation damage.

  19. Andromede project: Surface analysis and modification with probes from hydrogen to nano-particles in the MeV energy range

    Energy Technology Data Exchange (ETDEWEB)

    Eller, Michael J.; Cottereau, Evelyne [Institut de Physique Nucléaire d’Orsay, UMR8608, CNRS/IN2P3, Université Paris-Sud 11, F-91406 Orsay (France); Rasser, Bernard; Verzeroli, Elodie [Orsay Physics, ZAC Saint Charles, 95 Av des Monts Auréliens, 13710 Fuveau (France); Agnus, Benoit; Gaubert, Gabriel; Donzel, Xavier [Pantechnik SA, 13 rue de la Résistance, 14400 Bayeux (France); Delobbe, Anne [Orsay Physics, ZAC Saint Charles, 95 Av des Monts Auréliens, 13710 Fuveau (France); Della-Negra, Serge, E-mail: dellaneg@ipno.in2p3.fr [Institut de Physique Nucléaire d’Orsay, UMR8608, CNRS/IN2P3, Université Paris-Sud 11, F-91406 Orsay (France)

    2015-12-15

    The Andromede project is the center of a multi-disciplinary team which will build a new instrument for surface modification and analysis using the impact of probes from hydrogen to nano-particles (Au{sub 400}{sup +4}) in the MeV range. For this new instrument a series of atomic, polyatomic, molecular and nano-particle ion beams will be delivered using two ion sources in tandem, a liquid metal ion source and an electron cyclotron resonance source. The delivered ion beams will be accelerated to high energy with a 4 MeV van de Graaff type accelerator. By using a suite of probes in the MeV energy range, ion beam analysis techniques, MeV atomic and cluster secondary ion mass spectrometry can all be performed in one location. A key feature of the instrument is its ability to produce an intense beam for injection into the accelerator. The commissioning of the two sources shows that intense beams from atomic ions to nano-particles can be delivered for subsequent acceleration. The calculations and measurements for the two sources are presented.

  20. Stimulated Raman adiabatic passage for improved performance of a cold-atom electron and ion source

    Science.gov (United States)

    Sparkes, B. M.; Murphy, D.; Taylor, R. J.; Speirs, R. W.; McCulloch, A. J.; Scholten, R. E.

    2016-08-01

    We implement high-efficiency coherent excitation to a Rydberg state using stimulated Raman adiabatic passage in a cold-atom electron and ion source. We achieve an efficiency of 60% averaged over the laser excitation volume with a peak efficiency of 82%, a 1.6 times improvement relative to incoherent pulsed-laser excitation. Using pulsed electric field ionization of the Rydberg atoms we create electron bunches with durations of 250 ps. High-efficiency excitation will increase source brightness, crucial for ultrafast electron diffraction experiments, and coherent excitation to high-lying Rydberg states could allow for the reduction of internal bunch heating and the creation of a high-speed single-ion source.

  1. Laser-based X-ray and electron source for X-ray fluorescence studies

    CERN Document Server

    Brozas, F Valle; Roso, L; Conde, A Peralta

    2016-01-01

    In this work we present a modification to conventional X-rays fluorescence using electrons as excitation source, and compare it with the traditional X-ray excitation for the study of pigments. For this purpose we have constructed a laser-based source capable to produce X-rays as well as electrons. Because of the large penetration depth of X-rays, the collected fluorescence signal is a combination of several material layers of the artwork under study. However electrons are stopped in the first layers allowing therefore a more superficial analysis. We show that the combination of both excitation sources can provide extremely valuable information about the structure of the artwork.

  2. Towards the Adoption of Open Source and Open Access Electronic Health Record Systems

    Directory of Open Access Journals (Sweden)

    Ilias Maglogiannis

    2012-01-01

    Full Text Available As the Electronic Health Record (EHR systems constantly expand to support more clinical activities and their implementations in healthcare organizations become more widespread, several communities have been working intensively for several years to develop open access and open source EHR software, aiming at reducing the costs of EHR deployment and maintenance. In this paper, we describe and evaluate the most popular open source electronic medical records such as openEMR, openMRS and patientOS, providing their technical features and potentials. These systems are considered quite important due to their prevalence. The article presents the key features of each system and outlines the advantages and problems of Open Source Software (OSS Systems through a review of the literature, in order to demonstrate the possibility of their adoption in modern electronic healthcare systems. Also discussed are the future trends of OS EHRs in the context of the Personal Health Records and mobile computing paradigm.

  3. Electron optics simulation for designing carbon nanotube based field emission x-ray source

    Science.gov (United States)

    Sultana, Shabana

    In this dissertation, electron optics simulation for designing carbon nanotube (CNT) based field emission x-ray source for medical imaging applications will be presented. However, for design optimization of x-ray tubes accurate electron beam optics simulation is essential. To facilitate design of CNT x-ray sources a commercial 3D finite element software has been chosen for extensive simulation. The results show that a simplified model of uniform electron field emission from the cathode surface is not sufficient when compared to experimental measurements. This necessitated the development of a refined model to describe a macroscopic field emission CNT cathode for electron beam optics simulations. The model emulates the random distribution of CNTs and the associated variation of local field enhancement factor. The main parameter of the model has been derived empirically from the experimentally measured I-V characteristics of the CNT cathode. Simulation results based on this model agree well with experiments which include measurements of the transmission rate and focus spot size. The model provides a consistent simulation platform for optimization of electron beam optics in CNT x-ray source design. A systematic study of electron beam optics in CNT x-ray tubes led to the development of a new generation of compact x-ray source with multiple pixels. A micro focus field emission x-ray source with a variable focal spot size has been fully characterized and evaluated. It has been built and successfully integrated into micro-CT scanners which are capable of dynamic cardiac imaging of free-breathing small animals with high spatial and temporal resolutions. In addition a spatially distributed high power multi-beam x-ray source has also been designed and integrated into a stationary digital breast tomosynthesis (s-DBT) configuration. This system has the potential to reduce the total scan time to 4 seconds and yield superior image quality in breast imaging.

  4. Observation of transverse space charge effects in a multi-beamlet electron bunch produced in a photo-emission electron source

    Energy Technology Data Exchange (ETDEWEB)

    Rihaoui, M.; /Northern Illinois U. /NICADD, DeKalb; Gai, W.; /Argonne; Piot, P.; /Northern Illinois U. /NICADD, DeKalb /FERMILAB; Power, J.G.; /Argonne; Ysof, Z.; /Argonne

    2008-09-01

    A 'multiple beamlet' experiment aimed at investigating the transverse space charge effect was recently conducted at the Argonne Wakefield Accelerator. The experiment generated a symmetric pattern of 5 beamlets on the photocathode of the RF gun with the drive laser. We explored the evolution of the thereby produced 5 MeV, space-charge dominated electron beamlets in the 2m drift following the RF photocathode gun for various external focusing. Two important effects were observed and benchmarked using the particle-in-cell beam dynamics code IMPACT-T. In this paper, we present our experimental observation and their benchmarking with Impact-T.

  5. A comparison of experimental and theoretical electron energy distribution functions in a multicusp ion source

    Energy Technology Data Exchange (ETDEWEB)

    Bretagne, J. (Paris-11 Univ., 91 - Orsay (France)); Graham, W.G. (Queen' s Univ., Belfast, Northern Ireland (UK). Dept. of Physics); Hopkins, M.B. (Dublin City Univ. (Ireland). Dept. of Physics)

    1991-05-14

    Experimental and theoretical electron energy distribution functions (EEDFS) measured in and calculated for the driver of a multicusp ion source operating in hydrogen are compared. The results show that atomic physics based theoretical models can accurately predict the EEDF in such discharges if some appropriate experimentally determined quantities are used as input parameters. The magnitude and shape of the EEDF is found to be particularly sensitive to the effective surface area to volume ratio for electrons. (author).

  6. A 20 kV, 5 A, 1 ns Risetime Pulsed Electron Beam Source

    Institute of Scientific and Technical Information of China (English)

    Chen Yulan; Zeng Zhengzhong; Wang Haiyang; Ma Lianying

    2005-01-01

    A 20 kV, 1 ns risetime pulsed electron beam source was developed using an extremely small gap (0.1 mm) diode driven by a sub-nanosecond risetime, 10 kV rectangular pulse generator. A beam current of 5 A was detected by using a fast response Faraday cup at a distance of 2 cm away from a grid anode. The shot to shot variation of the electron beam pulse was less than 10%.

  7. Highly charged ion X-rays from Electron-Cyclotron Resonance Ion Sources

    OpenAIRE

    Indelicato, Paul; Boucard, S.; Covita, D. S.; Gotta, D.; Gruber, A; Hirtl, A.; Fuhrmann, H.; Le Bigot, E.-O.; Schlesser, S.; dos Santos, J. M. F.; Simons, L.M.; Stingelin, L.; Trassinelli, Martino; Veloso, J.; Wasser, A.

    2006-01-01

    Radiation from the highly-charged ions contained in the plasma of Electron-Cyclotron Resonance Ion Sources constitutes a very bright source of X-rays. Because the ions have a relatively low kinetic energy ($\\approx 1$~eV) transitions can be very narrow, containing only small Doppler broadening. We describe preliminary accurate measurements of two and three-electron ions with $Z=16$--18. We show how these measurement can test sensitively many-body relativistic calculations or can be used as X-...

  8. S-band linac-based X-ray source with {pi}/2-mode electron linac

    Energy Technology Data Exchange (ETDEWEB)

    Deshpande, Abhay, E-mail: abhay@post.kek.jp [Department of Accelerator Science, School of High Energy Accelerator Science, Graduate University for Advanced Studies, Shonan International Village, Hayama, Miura, Kanagawa 240-0193 (Japan); Society for Applied Microwave Electronic Engineering and Research (SAMEER), R and D Laboratory of the Government of India, IIT Campus, Powai, Mumbai 400 076 (India); Araki, Sakae [High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan); Dixit, Tanuja [Society for Applied Microwave Electronic Engineering and Research (SAMEER), R and D Laboratory of the Government of India, IIT Campus, Powai, Mumbai 400 076 (India); Fukuda, Masafumi [High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan); Krishnan, R; Pethe, Sanjay [Society for Applied Microwave Electronic Engineering and Research (SAMEER), R and D Laboratory of the Government of India, IIT Campus, Powai, Mumbai 400 076 (India); Sakaue, Kazuyuki [Waseda University, Shinjuku-ku, Tokyo 169-8555 (Japan); Terunuma, Nobuhiro; Urakawa, Junji [High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan); Washio, Masakazu [Waseda University, Shinjuku-ku, Tokyo 169-8555 (Japan)

    2011-05-01

    The activities with the compact X-ray source are attracting more attention, particularly for the applications of the source in medical fields. We propose the fabrication of a compact X-ray source using the SAMEER electron linear accelerator and the KEK laser undulator X-ray source (LUCX) technologies. The linac developed at SAMEER is a standing wave side-coupled S-band linac operating in the {pi}/2 mode. In the proposed system, a photocathode RF gun will inject bunches of electrons in the linac to accelerate and achieve a high-energy, low-emittance beam. This beam will then interact with the laser in the laser cavity to produce X-rays of a type well suited for various applications. The side-coupled structure will make the system more compact, and the {pi}/2 mode of operation will enable a high repetition rate operation, which will help to increase the X-ray yield.

  9. Synchrotron light sources and free-electron lasers accelerator physics, instrumentation and science applications

    CERN Document Server

    Khan, Shaukat; Schneider, Jochen; Hastings, Jerome

    2016-01-01

    Hardly any other discovery of the nineteenth century did have such an impact on science and technology as Wilhelm Conrad Röntgen’s seminal find of the X-rays. X-ray tubes soon made their way as excellent instruments for numerous applications in medicine, biology, materials science and testing, chemistry and public security. Developing new radiation sources with higher brilliance and much extended spectral range resulted in stunning developments like the electron synchrotron and electron storage ring and the freeelectron laser. This handbook highlights these developments in fifty chapters. The reader is given not only an inside view of exciting science areas but also of design concepts for the most advanced light sources. The theory of synchrotron radiation and of the freeelectron laser, design examples and the technology basis are presented. The handbook presents advanced concepts like seeding and harmonic generation, the booming field of Terahertz radiation sources and upcoming brilliant light sources dri...

  10. Plasma breakdown diagnostics with the biased disc of electron cyclotron resonance ion source

    Energy Technology Data Exchange (ETDEWEB)

    Tarvainen, O; Ropponen, T; Toivanen, V; Arje, J; Koivisto, H [University of Jyvaeskylae, Department of Physics, Accelerator Laboratory, PO Box 35 (YFL), 40500 Jyvaeskylae (Finland)], E-mail: olli.tarvainen@jyu.fi

    2009-08-15

    The electron cyclotron resonance ion sources at the JYFL (University of Jyvaeskylae, Department of Physics) accelerator laboratory have been operated in pulsed mode to study the time-resolved current signal from the biased discs of the ion sources. The purpose of the experiments is to gain an understanding of the ion source parameters affecting the time required for the transition from neutral gas to plasma. It was observed that the plasma breakdown time depends strongly on the neutral gas density, gas species and density of seed electrons. In particular, it was observed that a low power microwave signal at secondary frequency makes the breakdown time virtually independent of the neutral gas density. The results can be utilized for operation of ECR ion sources in the so-called preglow mode. A simple qualitative model, which is in good agreement with the experiments, has been developed to interpret the results.

  11. Analysis of Coherence Properties of 3-rd Generation Synchrotron Sources and Free-Electron Lasers

    CERN Document Server

    Vartanyants, I A

    2009-01-01

    A general theoretical approach based on the results of statistical optics is used for the analysis of the transverse coherence properties of 3-rd generation synchrotron sources and x-ray free-electron lasers (XFEL). Correlation properties of the wavefields are calculated at different distances from an equivalent Gaussian Schell-model source. This model is used to describe coherence properties of the five meter undulator source at the synchrotron storage ring PETRA III. In the case of XFEL sources the decomposition of the statistical fields into a sum of independently propagating transverse modes is used for the analysis of the coherence properties of these new sources. A detailed calculation is performed for the parameters of the SASE1 undulator at the European XFEL. It is demonstrated that only a few modes contribute significantly to the total radiation field of that source.

  12. The development of a room temperature electron cyclotron resonance ion source (Lanzhou electron cyclotron resonance ion source No. 4) with evaporative cooling technology at Institute of Modern Physics

    Energy Technology Data Exchange (ETDEWEB)

    Lu, W., E-mail: luwang@impcas.ac.cn; Sun, L. T.; Qian, C.; Feng, Y. C.; Ma, H. Y.; Zhang, X. Z.; Ma, B. H.; Zhao, H. W. [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 73000 (China); Guo, J. W.; Fang, X.; Yang, Y. [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 73000 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Xiong, B.; Guo, S. Q.; Ruan, L. [Institute of Electrical Engineering, CAS, Beijing 100190 (China)

    2015-04-15

    LECR4 (Lanzhou electron cyclotron resonance ion source No. 4) has been successfully constructed at IMP and has also been connected with the Low Energy Beam Transport (LEBT) and Radio Frequency Quadrupole (RFQ) systems. These source magnet coils are cooled through evaporative cooling technology, which is the first attempt with an ECR ion source in the world. The maximum mirror field is 2.5 T (with iron plug) and the effective plasma chamber volume is 1.2 l. It was designed to be operated at 18 GHz and aimed to produce intense multiple charge state heavy ion beams for the linear injector project SSC-Linac at IMP. In February 2014, the first analyzed beam at 18 GHz was extracted. During about three months’ commissioning, some outstanding results have been achieved, such as 1.97 emA of O{sup 6+}, 1.7 emA of Ar{sup 8+}, 1.07 emA of Ar{sup 9+}, and 118 euA of Bi{sup 28+}. The source has also successfully delivered O{sup 5+} and Ar{sup 8+} ion beams for RFQ commissioning in April 2014. This paper will give a brief overview of the design of LECR4. Then, the latest results of this source at 18 GHz will be presented.

  13. The development of a room temperature electron cyclotron resonance ion source (Lanzhou electron cyclotron resonance ion source No. 4) with evaporative cooling technology at Institute of Modern Physics.

    Science.gov (United States)

    Lu, W; Sun, L T; Qian, C; Guo, J W; Fang, X; Feng, Y C; Yang, Y; Ma, H Y; Zhang, X Z; Ma, B H; Xiong, B; Guo, S Q; Ruan, L; Zhao, H W

    2015-04-01

    LECR4 (Lanzhou electron cyclotron resonance ion source No. 4) has been successfully constructed at IMP and has also been connected with the Low Energy Beam Transport (LEBT) and Radio Frequency Quadrupole (RFQ) systems. These source magnet coils are cooled through evaporative cooling technology, which is the first attempt with an ECR ion source in the world. The maximum mirror field is 2.5 T (with iron plug) and the effective plasma chamber volume is 1.2 l. It was designed to be operated at 18 GHz and aimed to produce intense multiple charge state heavy ion beams for the linear injector project SSC-Linac at IMP. In February 2014, the first analyzed beam at 18 GHz was extracted. During about three months' commissioning, some outstanding results have been achieved, such as 1.97 emA of O(6+), 1.7 emA of Ar(8+), 1.07 emA of Ar(9+), and 118 euA of Bi(28+). The source has also successfully delivered O(5+) and Ar(8+) ion beams for RFQ commissioning in April 2014. This paper will give a brief overview of the design of LECR4. Then, the latest results of this source at 18 GHz will be presented.

  14. A hollow cathode ion source for production of primary ions for the BNL electron beam ion source.

    Science.gov (United States)

    Alessi, James; Beebe, Edward; Carlson, Charles; McCafferty, Daniel; Pikin, Alexander; Ritter, John

    2014-02-01

    A hollow cathode ion source, based on one developed at Saclay, has been modified significantly and used for several years to produce all primary 1+ ions injected into the Relativistic Heavy Ion Collider Electron Beam Ion Source (EBIS) at Brookhaven. Currents of tens to hundreds of microamperes have been produced for 1+ ions of He, C, O, Ne, Si, Ar, Ti, Fe, Cu, Kr, Xe, Ta, Au, and U. The source is very simple, relying on a glow discharge using a noble gas, between anode and a solid cathode containing the desired species. Ions of both the working gas and ionized sputtered cathode material are extracted, and then the desired species is selected using an ExB filter before being transported into the EBIS trap for charge breeding. The source operates pulsed with long life and excellent stability for most species. Reliable ignition of the discharge at low gas pressure is facilitated by the use of capacitive coupling from a simple toy plasma globe. The source design, and operating experience for the various species, is presented.

  15. A hollow cathode ion source for production of primary ions for the BNL electron beam ion source

    Energy Technology Data Exchange (ETDEWEB)

    Alessi, James, E-mail: alessi@bnl.gov; Beebe, Edward; Carlson, Charles; McCafferty, Daniel; Pikin, Alexander; Ritter, John [Collider-Accelerator Department, Brookhaven National Laboratory, Upton, New York 11973 (United States)

    2014-02-15

    A hollow cathode ion source, based on one developed at Saclay, has been modified significantly and used for several years to produce all primary 1+ ions injected into the Relativistic Heavy Ion Collider Electron Beam Ion Source (EBIS) at Brookhaven. Currents of tens to hundreds of microamperes have been produced for 1+ ions of He, C, O, Ne, Si, Ar, Ti, Fe, Cu, Kr, Xe, Ta, Au, and U. The source is very simple, relying on a glow discharge using a noble gas, between anode and a solid cathode containing the desired species. Ions of both the working gas and ionized sputtered cathode material are extracted, and then the desired species is selected using an ExB filter before being transported into the EBIS trap for charge breeding. The source operates pulsed with long life and excellent stability for most species. Reliable ignition of the discharge at low gas pressure is facilitated by the use of capacitive coupling from a simple toy plasma globe. The source design, and operating experience for the various species, is presented.

  16. Status of the Linac Coherent Light Source

    Energy Technology Data Exchange (ETDEWEB)

    Galayda, John N.; /SLAC

    2011-11-04

    The Linac Coherent Light Source (LCLS) is a free electron laser facility in construction at Stanford Linear Accelerator Center. It is designed to operate in the wavelength range 0.15-1.5 nanometers. At the time of this conference, civil construction of new tunnels and buildings is complete, the necessary modifications to the SLAC linac are complete, and the undulator system and x-ray optics/diagnostics are being installed. The electron gun, 135 MeV injector linac and 250 MeV bunch compressor were commissioned in 2007. Accelerator commissioning activities are presently devoted to the achievement of performance goals for the completed 14 GeV linac.

  17. Ultrafast Science Opportunities with Electron Microscopy

    Energy Technology Data Exchange (ETDEWEB)

    DURR, HERMANN; Wang, X.J., ed.

    2016-04-28

    X-rays and electrons are two of the most fundamental probes of matter. When the Linac Coherent Light Source (LCLS), the world’s first x-ray free electron laser, began operation in 2009, it transformed ultrafast science with the ability to generate laser-like x-ray pulses from the manipulation of relativistic electron beams. This document describes a similar future transformation. In Transmission Electron Microscopy, ultrafast relativistic (MeV energy) electron pulses can achieve unsurpassed spatial and temporal resolution. Ultrafast temporal resolution will be the next frontier in electron microscopy and can ideally complement ultrafast x-ray science done with free electron lasers. This document describes the Grand Challenge science opportunities in chemistry, material science, physics and biology that arise from an MeV ultrafast electron diffraction & microscopy facility, especially when coupled with linac-based intense THz and X-ray pump capabilities.

  18. Note: Production of a mercury beam with an electron cyclotron resonance ion source.

    Science.gov (United States)

    Vondrasek, R; Pardo, R; Scott, R

    2013-11-01

    An electron cyclotron resonance ion source has been utilized to produce mercury beams with intensities of 4.5 eμA of (202)Hg(29+) and 3.0 eμA of (202)Hg(31+) from natural abundance mercury metal. The production technique relies on the evaporation of liquid mercury into the source plasma vacuum region and utilizes elemental mercury instead of a volatile organic compound as the neutral feed material.

  19. Medieval Sources and Present-Day Folklore Materials on Saints in an Electronic Encyclopedia

    OpenAIRE

    Rangochev, Konstantin; Dimitrova, Margaret; Paneva-Marinova, Desislava

    2012-01-01

    This paper discusses the variety of the digitized content of an electronic encyclopedia on the veneration of saints according to Bulgarian sources. The emphasis is on medieval Slavonic Church manuscripts and on present-day records of Bulgarian folklore narratives and songs. The combination of these sources provokes discussion of the so-called folklore Christianity and adds new dimensions to the understanding of the role of the cults of saints for culture and of the religiosity ...

  20. Influence of gas pressure on electron beam emission current of pulsed cathodic-arc-based forevacuum plasma electron source

    Science.gov (United States)

    Burdovitsin, Victor A.; Kazakov, Andrey V.; Medovnik, Alexander V.; Oks, Efim M.

    2017-09-01

    We describe our experimental investigation of the effect of background gas pressure on the emission parameters of a pulsed cathodic-arc-based forevacuum-pressure plasma-cathode electron source. We find that increased gas pressure over the range 4-16 Pa significantly reduces the beam current rise-time and significantly increases the emission current amplitude. For example, at a discharge current of 20 A, increasing the working gas pressure from 4 Pa to 16 Pa increases the emission current from 8 A to 18 A and shortens the beam rise-time from 50 μs to 20 μs. This influence of gas pressure on the electron beam parameters can be explained by the effect of arc discharge current switching from the anode to emission. In our case, the current switching effect is caused by increased working gas pressure. In the forevacuum pressure range, the increase of the electron emission current with the growth of gas pressure is due to a rise in the emission plasma potential which is caused by ion back-streaming from the plasma formed in the electron beam transport region. A model describing the influence of gas pressure on the electron emission from the plasma is presented.