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Sample records for mev electron source

  1. 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 of ...

  2. Microwave source development for 9 MeV RF electron LINAC for cargo scanning

    International Nuclear Information System (INIS)

    Yadav, V.; Chandan, Shiv; Tillu, A.R.; Bhattacharjee, D.; Chavan, R.B.; Dixit, K.P.; Mittal, K.C.; Gantayet, L.M.

    2011-01-01

    For cargo scanning, high energy X-rays are required. These X-rays can be generated from accelerated electrons. A 9 MeV Cargo scanning RF LINAC has been developed at ECIL, Hyderabad. The Microwave power source required for RF Linac is a klystron-based system generating 5.5 MW peak, 10 kW average, at 2.856 GHz. Various components required for microwave source were identified, procured, tested and integrated into the source. Microwave source was tested on water load, then it was connected to LINAC and RF conditioning and e-beam trials were successfully done. For operating the microwave source, a PC based remote handling system was also designed and developed for operating various power supplies and instruments of the microwave source, including the Klystron modulator, Signal generator and other devices. The accelerator operates in pulse mode, requiring synchronous operation of the Klystron modulator, RF driver amplifier and E-gun modulator. For this purpose, a synchronous trigger generator was designed and developed. This paper describes the development and testing of microwave source and its remote operating system. The results of beam trials are also discussed in this paper. (author)

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

    International Nuclear Information System (INIS)

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

    2011-01-01

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

  4. Free electron laser facilities employing a 150-MeV linac injector for Saga synchrotron light source

    International Nuclear Information System (INIS)

    Tomimasu, T.; Yasumoto, M.; Ochiai, Y.; Ishibashi, M.; Murayama, T.

    1999-01-01

    Free electron laser (FEL) facilities as the FELI FEL Facility are proposed, for which a 150-MeV linac type injector for a Saga synchrotron light source (SLS) is employed in FEL mode. The linac has two operating modes; short macropulse mode a 1 μs at 150 MeV for injection to a 1 - 1.3-GeV third generation type storage ring and long macropulse mode of 12 μs at 100 MeV for four FEL Facilities. The macropulse beam consists of a train of several ps, 0.6 nC microbunches (peak current 100 A) repeating at 89.25 MHz. We are aiming to supply high power level photon beams covering an attractive wavelength range from 0.05 nm (25 keV) to 200 μm (0.006 eV) for scientific researches, bio-medical and industrial applications, using the Saga third generation type SLS with a superconducting wiggler and the proposed four FEL Facilities. (author)

  5. 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...

  6. 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.

  7. 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).

  8. Characterization and optimization of laser-driven electron and photon sources in keV and MeV energy ranges

    International Nuclear Information System (INIS)

    Bonnet, Thomas

    2013-01-01

    This work takes place in the framework of the characterization and the optimization of laser-driven electron and photon sources. With the goal of using these sources for nuclear physics experiments, we focused on 2 energy ranges: one around a few MeV and the other around a few tens of keV. The first part of this work is thus dedicated to the study of detectors routinely used for the characterization of laser-driven particle sources: Imaging Plates. A model has been developed and is fitted to experimental data. Response functions to electrons, photons, protons and alpha particles are established for SR, MS and TR Fuji Imaging Plates for energies ranging from a few keV to several MeV. The second part of this work present a study of ultrashort and intense electron and photon sources produced in the interaction of a laser with a solid or liquid target. An experiment was conducted at the ELFIE facility at LULI where beams of electrons and photons were accelerated up to several MeV. Energy and angular distributions of the electron and photons beams were characterized. The sources were optimized by varying the spatial extension of the plasma at both the front and the back end of the initial target position. In the optimal configuration of the laser-plasma coupling, more than 1011 electrons were accelerated. In the case of liquid target, a photon source was produced at a high repetition rate on an energy range of tens of keV by the interaction of the AURORE Laser at CELIA (10 16 W.cm -2 ) and a melted gallium target. It was shown that both the mean energy and the photon number can be increased by creating gallium jets at the surface of the liquid target with a pre-pulse. A physical interpretation supported by numerical simulations is proposed. (author)

  9. Upper limit on the inner radiation belt MeV electron intensity

    Science.gov (United States)

    Li, X; Selesnick, RS; Baker, DN; Jaynes, AN; Kanekal, SG; Schiller, Q; Blum, L; Fennell, J; Blake, JB

    2015-01-01

    No instruments in the inner radiation belt are immune from the unforgiving penetration of the highly energetic protons (tens of MeV to GeV). The inner belt proton flux level, however, is relatively stable; thus, for any given instrument, the proton contamination often leads to a certain background noise. Measurements from the Relativistic Electron and Proton Telescope integrated little experiment on board Colorado Student Space Weather Experiment CubeSat, in a low Earth orbit, clearly demonstrate that there exist sub-MeV electrons in the inner belt because their flux level is orders of magnitude higher than the background, while higher-energy electron (>1.6 MeV) measurements cannot be distinguished from the background. Detailed analysis of high-quality measurements from the Relativistic Electron and Proton Telescope on board Van Allen Probes, in a geo-transfer-like orbit, provides, for the first time, quantified upper limits on MeV electron fluxes in various energy ranges in the inner belt. These upper limits are rather different from flux levels in the AE8 and AE9 models, which were developed based on older data sources. For 1.7, 2.5, and 3.3 MeV electrons, the upper limits are about 1 order of magnitude lower than predicted model fluxes. The implication of this difference is profound in that unless there are extreme solar wind conditions, which have not happened yet since the launch of Van Allen Probes, significant enhancements of MeV electrons do not occur in the inner belt even though such enhancements are commonly seen in the outer belt. Key Points Quantified upper limit of MeV electrons in the inner belt Actual MeV electron intensity likely much lower than the upper limit More detailed understanding of relativistic electrons in the magnetosphere PMID:26167446

  10. Crosslinking of commercial polyethylenes by 10 MeV electrons

    International Nuclear Information System (INIS)

    Singh, A.; Lopata, V.J.; Kremers, W.; Sze, Yu-keung

    1995-08-01

    Commercial polyethylenes were irradiated with 10 MeV electrons to induce crosslinking. The gel fraction data measured as a function of total dose suggests that crosslinking proceeds on irradiation, as expected. A number of the properties of the irradiated polyethylenes, such as the degree of oxidation, crystallinity and thermal degradation, were studied by Fourier transform infrared/photo acoustic spectroscopy, X-ray diffraction, and a pyrolysis technique coupled with gas chromatography and mass spectrometry. The results of this study suggest that commercial polyethylenes can be crosslinked to a gel fraction of ∼70%, required for wire and cable applications, by 10 MeV electrons. (author). 35 refs., 6 figs

  11. Optimisation of 12 MeV electron beam simulation using variance reduction technique

    International Nuclear Information System (INIS)

    Jayamani, J; Aziz, M Z Abdul; Termizi, N A S Mohd; Kamarulzaman, F N Mohd

    2017-01-01

    Monte Carlo (MC) simulation for electron beam radiotherapy consumes a long computation time. An algorithm called variance reduction technique (VRT) in MC was implemented to speed up this duration. This work focused on optimisation of VRT parameter which refers to electron range rejection and particle history. EGSnrc MC source code was used to simulate (BEAMnrc code) and validate (DOSXYZnrc code) the Siemens Primus linear accelerator model with the non-VRT parameter. The validated MC model simulation was repeated by applying VRT parameter (electron range rejection) that controlled by global electron cut-off energy 1,2 and 5 MeV using 20 × 10 7 particle history. 5 MeV range rejection generated the fastest MC simulation with 50% reduction in computation time compared to non-VRT simulation. Thus, 5 MeV electron range rejection utilized in particle history analysis ranged from 7.5 × 10 7 to 20 × 10 7 . In this study, 5 MeV electron cut-off with 10 × 10 7 particle history, the simulation was four times faster than non-VRT calculation with 1% deviation. Proper understanding and use of VRT can significantly reduce MC electron beam calculation duration at the same time preserving its accuracy. (paper)

  12. 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.

  13. 10 MeV RF electron linac for industrial applications

    International Nuclear Information System (INIS)

    2017-01-01

    Electron linacs have found numerous applications in the field of radiation processing on an industrial scale. High power RF electron linacs are commonly used for food irradiation, medical sterilization, cross-linking of polymers, etc. For this purpose, the 10 MeV RF linac has been indigenously designed, developed, commissioned and is being used regularly at 3 kW beam power. This paper gives a brief description of the linac and its utilization for various applications. Safety considerations and regulatory aspects of the linac are also discussed

  14. Interpretation of recent positron-electron measurements between 20 and 800 MeV

    International Nuclear Information System (INIS)

    Pellerin, C.J.; Hartman, R.C.

    1975-01-01

    The recent positron and negatron spectra measured by Hartman and Pellerin (see pages 402-407) are discussed with regard to the problem of solar modulation. At energies above 180 MeV, the spherically symmetric Fokker-Planck equation with a diffusion coefficient proportional to particle rigidity provides reasonable fits to both the positron and total electron data. At energies below 180 MeV the data are consistent with a continuation of the same diffusion coefficient and local source of negatrons, or a change in the diffusion coefficient to a constant value. (orig.) [de

  15. Out-of-ecliptic quiet time MeV electron increases: Ulysses COSPIN/KET observations

    International Nuclear Information System (INIS)

    Heber, B.; Ferreira, S.E.S.; Potgieter, M.S.; Henize, V.K.; Moeketsi, D.M.; Fichtner, H.; Kissmann, R.

    2004-01-01

    The propagation of cosmic rays in turbulent magnetic fields can be studied in detail by way of in-situ measurements of energetic particles in the three-dimensional heliosphere. Measurements of 3-20 MeV electrons from 1990 to 2003 have been made by the Kiel Electron Telescope (KET) onboard the Ulysses spacecraft during varying solar conditions. In order to interpret these measurements, it is necessary to distinguish between solar, galactic and Jovian electrons and to investigate their propagation, by using sophisticated particle propagation models. The solar contribution to the MeV electron intensities can be excluded by analyzing the electron energy spectra and the nuclei time histories. The residual electron intensities can be reasonably described by modulation models taking into account galactic cosmic rays as well as Jovian electrons using different diffusion coefficients for solar minimum and maximum. The way in which the relative contribution of Jovian (point source in the ecliptic) and galactic electrons (isotropic source) varies along the Ulysses orbit is strongly dependent on the choice of these coefficients. Since the 1970's quiet time electron increases have been observed in the ecliptic and interpreted as Jovian electron increases. Therefore, the occurrence of such quiet time electron increases is an indicator for a dominant Jovian contribution to the measured MeV electron intensities. At solar minimum and maximum such events have been observed up to ∼30 deg. and ∼45 deg. These observations are crucial for a determination of the diffusion parameters. At solar maximum a more efficient latitude transport is needed to account for the electron intensity variations

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

    Science.gov (United States)

    Longfellow, Brenden

    2014-09-01

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

  17. Construction of 100 MeV electron linac in Kyoto University

    International Nuclear Information System (INIS)

    Shirai, Toshiyuki; Sugimura, Takeshi; Kando, Masaki

    1995-01-01

    An electron linear accelerator and a compact storage ring have been constructed at Kyoto University. The beam energy of the storage ring is 300 MeV and will be utilized as a synchrotron radiation source. The output beam energy of the linac is 100 MeV and the designed beam current is 100 mA at the pulse width of 1 μsec. The construction of the linac had been finished and the test is under going. The electron beam of 300 mA is extracted from the electron gun and the peak RF power of 20 MW is successfully fed to the accelerating structures at the pulse width of 2 μsec. (author)

  18. 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.

  19. Control system for 10 MeV irradiation electron linac

    International Nuclear Information System (INIS)

    Zeng Ziqiang; Zhang Lifeng; Lu Weixing; Gao Zhenjiang; Zhang Yan; Han Guangwen; Wang Shuxian

    2005-01-01

    Control system of the 10 MeV electron linac using Distributed Control System (DCS) was studied. The hardware of control system consists of four SIEMENS PLCs and monitor computer, the software bases on STEP 7, Labwindows/CVI and SQL Server. The bus between the monitor computer and the main PLC is 100 M industrial networks, between PLCs is MPI bus, between PLC and remote partner is PROFIBUS, between PLC and terminals is RS485/422. The software of control system can provide a friendly human machine interface to operate the machine, protect the human and equipment from risk, and storage the status of the accelerator real time to the database. The monitor and maintenance of the linac can been carried out not only on local computer or local network, but also in internet. (author)

  20. A 14-MeV beam-plasma neutron source for materials testing

    International Nuclear Information System (INIS)

    Futch, A.H.; Coensgen, F.H.; Damm, C.C.; Molvik, A.W.

    1989-01-01

    The design and performance of 14-MeV beam-plasma neutron sources for accelerated testing of fusion reactor materials are described. Continuous production of 14-MeV neutron fluxes in the range of 5 to 10 MW/m 2 at the plasma surface are produced by D-T reactions in a two-component plasma. In the present designs, 14-MeV neutrons result from collisions of energetic deuterium ions created by transverse injection of 150-keV deuterium atoms on a fully ionized tritium target plasma. The beam energy, which deposited at the center of the tritium column, is transferred to the warm plasma by electron drag, which flows axially to the end regions. Neutral gas at high pressure absorbs the energy in the tritium plasma and transfers the heat to the walls of the vacuum vessel. The plasma parameters of the neutron source, in dimensionless units, have been achieved in the 2XIIB high-β plasma. The larger magnetic field of the present design permits scaling to the higher energy and density of the neutron source design. In the extrapolation, care has been taken to preserve the scaling and plasma attributes that contributed to equilibrium, magnetohydrodynamic (MHD) stability, and microstability in 2XIIB. The performance and scaling characteristics are described for several designs chosen to enhance the thermal isolation of the two-component plasmas. 11 refs., 3 figs., 3 tabs

  1. Polarized electron sources

    International Nuclear Information System (INIS)

    Clendenin, J.E.

    1995-05-01

    Polarized electron sources for high energy accelerators took a significant step forward with the introduction of a new laser-driven photocathode source for the SLC in 1992. With an electron beam polarization of >80% and with ∼99% uptime during continuous operation, this source is a key factor in the success of the current SLC high-energy physics program. The SLC source performance is used to illustrate both the capabilities and the limitations of solid-state sources. The beam requirements for future colliders are similar to that of the SLC with the addition in most cases of multiple-bunch operation. A design for the next generation accelerator source that can improve the operational characteristics and at least minimize some of the inherent limitations of present sources is presented. Finally, the possibilities for producing highly polarized electron beams for high-duty-factor accelerators are discussed

  2. Investigation of transversal nuclear excitation in 208Pb at excitation energies between 6 MeV and 8 MeV using inelastic electron scattering

    International Nuclear Information System (INIS)

    Frey, R.W.

    1978-01-01

    Using high resolution inelastic electron scattering magnitic dipole and quadrupole excitations in 208 Pb were investigated in the energy range between 6 MeV and 8 MeV. The electron energy was 50 MeV and 63.5 MeV. With a mean absolute energy resolution of 33 kev. 44 excited states were found in the above energy range. The measured angular distributions were compared with DWBA-calculations using random phase approximated wave functions. (FKS)

  3. Polarized electron sources

    International Nuclear Information System (INIS)

    Prepost, R.

    1994-01-01

    The fundamentals of polarized electron sources are described with particular application to the Stanford Linear Accelerator Center. The SLAC polarized electron source is based on the principle of polarized photoemission from Gallium Arsenide. Recent developments using epitaxially grown, strained Gallium Arsenide cathodes have made it possible to obtain electron polarization significantly in excess of the conventional 50% polarization limit. The basic principles for Gallium and Arsenide polarized photoemitters are reviewed, and the extension of the basic technique to strained cathode structures is described. Results from laboratory measurements of strained photocathodes as well as operational results from the SLAC polarized source are presented

  4. Polarized electron sources

    Energy Technology Data Exchange (ETDEWEB)

    Prepost, R. [Univ. of Wisconsin, Madison, WI (United States)

    1994-12-01

    The fundamentals of polarized electron sources are described with particular application to the Stanford Linear Accelerator Center. The SLAC polarized electron source is based on the principle of polarized photoemission from Gallium Arsenide. Recent developments using epitaxially grown, strained Gallium Arsenide cathodes have made it possible to obtain electron polarization significantly in excess of the conventional 50% polarization limit. The basic principles for Gallium and Arsenide polarized photoemitters are reviewed, and the extension of the basic technique to strained cathode structures is described. Results from laboratory measurements of strained photocathodes as well as operational results from the SLAC polarized source are presented.

  5. Nonambipolar electron source

    International Nuclear Information System (INIS)

    Longmier, B.; Baalrud, S.; Hershkowitz, N.

    2006-01-01

    A radio frequency (rf) plasma-based electron source that does not rely on electron emission at a cathode surface has been constructed. All of the random electron flux incident on an exit aperture is extracted through an electron sheath resulting in total nonambipolar flow within the device when the ratio of the ion loss area to the electron loss area is approximately equal to the square root of the ratio of the ion mass to the electron mass, and the ion sheath potential drop at the chamber walls is much larger than T e /e. The nonambipolar electron source (NES) has an axisymmetric magnetic field of 100 G at the extraction aperture that results in a uniform plasma potential across the aperture, allowing the extraction of all the incident electron flux without the use of grids. A prototype NES has produced 15 A of continuous electron current, using 15 SCCM (SCCM denotes cubic centimeter per minute at STP) Ar, 1200 W rf power at 13.56 MHz, and 6 times gas utilization. Alternatively 8 A of electron current can be produced, using 3 SCCM Ar at 1200 W rf and 20 times gas utilization. NES could replace hollow cathode electron sources in a wide variety of applications

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

    CERN Multimedia

    CERN PhotoLab

    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.

  7. CESAR, 2 MeV electron storage ring.

    CERN Multimedia

    CERN PhotoLab

    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.

  8. Preliminary examination of induced radio activity in pepper by 10 MeV electron irradiation

    International Nuclear Information System (INIS)

    Furuta, Masakazu; Katayama, Tadashi; Ito, Norio; Mizohata, Akira; Matsunami, Tadao; Toratani, Hirokazu; Takeda, Atsuhiko

    1989-01-01

    β-ray measurement was performed on 10 MeV electron-irradiated black pepper and white pepper in order to reconfirm the wholesomeness of irradiated food and present unambiguous data to general consumers concerning about the induced radioactivity in the irradiated foods. From elemental composition of the samples and investigation of photonuclear reactions, several β-emmitters were listed up. But no radioactivity other than from natural sources was detected in the irradiated sample by β-ray counting with 2 π gass flow counter, suggesting that the induced β-emmitters in the irradiated sample was below the detection limit of its induced radioactivity. (author)

  9. Preliminary examination of induced radioactivity in pepper by 10 MeV electron irradiation

    International Nuclear Information System (INIS)

    Katayama, Tadashi; Furuta, Masakazu; Sibata, Setsuko; Ito, Norio; Mizohata, Akira; Matsunami, Tadao; Toratani, Hirokazu; Takeda, Atsuhiko.

    1991-01-01

    β-ray measurement was performed on 10 MeV electron-irradiated black pepper and white pepper with liquid scintillation counter in order to reconfirm the wholesomeness of irradiated foods and present unambiguous data to general consumers concerning about the induced radioactivity in the irradiated foods. In irradiated black pepper no radioactivity other than from natural source, un-irradiated one, was detected. But in irradiated white pepper, it was suggested that induced radioactivity might be detected if the detection method was more improved. (author)

  10. An 8 MeV H- cyclotron to charge the electron cooling system for HESR

    International Nuclear Information System (INIS)

    Pakhomchuk, V.; Papash, A.

    2006-01-01

    A compact cyclotron to accelerate negative hydrogen ions up to 8 MeV is considered as optimal solution to the problem of charging the high-voltage terminal of the electron cooling system for High Energy Storage Ring at GSI (HESR Project, Darmstadt). Physical as well as technical parameters of the accelerator are estimated. Different types of commercially available cyclotrons are compared as a possible source of a 1 mA H - beam for the HESR. An original design based on the application of well-established technical solutions for commercial accelerators is proposed

  11. 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.

  12. 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

  13. 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 Saveliev, J. Appl. Phys. 98, 093308 (2005). Ya. E. Krasik, A. Dunaevsky, and J. Felsteiner, Phys. Plasmas 8, 2466 (2001). D. Yarmolich, V. Vekselman, V. Tz. Gurovich, and Ya. E. Krasik, Phys. Rev. Lett. 100, 075004 (2008). J. Z. Gleizer, Y. Hadas and Ya. E. Krasik, Europhysics Lett. 82, 55001 (2008).

  14. Polarized electrons from GaAs for parity nonconservation studies and Moeller scattering at 250 MeV

    International Nuclear Information System (INIS)

    Cates, G.D. Jr.

    1987-01-01

    A description is given of a polarized electron source based on photoemission from GaAs with circularly polarized light, which was developed for use in the study of parity nonconservation (PNC) in e- 12 C scattering at 250 MeV at the MIT Bates Linear Accelerator Center. A multi-chamber vacuum system houses up to four GaAs crystals simultaneously, and is contained in a Faraday cage to provide 365 KeV in electrostatic acceleration. Stable operation is achieved through the use of a modulated cw laser. The PNC experiment is discussed, particularly with regards to its requirements on the source. The peak current from the source is 20 mA, resulting in a current in excess of 6 mA at high energy. The electron beam polarization has been measured to be 0.36 ± 0.004 using Moeller scattering at 250 MeV

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

    Indian Academy of Sciences (India)

    1Department of Physics, Mangalore Institute of Technology and Engineering, ... strate were irradiated with 1 MeV electrons, they showed high radiation tolerance ... under both forward and reverse bias in the temperature range of 270–315 K ...

  16. A 6.13MeV gamma reference source, measurement of the emission rate

    International Nuclear Information System (INIS)

    Robert, Andre; Blondel, Maurice; Morel, Jean; Thomas, Claude.

    1977-08-01

    A 6.13MeV γ reference source has been produced by using 13 C(α, nγ) 16 O reaction occurring in an intimate 13 C and 238 Pu mixture. With two walls made leak proof this standard source is easy handled and convenient to the calibration of detectors. The 6.13MeV gamma ray is emitted without Doeppler effect, is measured with an uncertainty of 6% by three independent methods [fr

  17. Imaging nanoscale spatial modulation of a relativistic electron beam with a MeV ultrafast electron microscope

    Science.gov (United States)

    Lu, Chao; Jiang, Tao; Liu, Shengguang; Wang, Rui; Zhao, Lingrong; Zhu, Pengfei; Liu, Yaqi; Xu, Jun; Yu, Dapeng; Wan, Weishi; Zhu, Yimei; Xiang, Dao; Zhang, Jie

    2018-03-01

    An accelerator-based MeV ultrafast electron microscope (MUEM) has been proposed as a promising tool to the study structural dynamics at the nanometer spatial scale and the picosecond temporal scale. Here, we report experimental tests of a prototype MUEM where high quality images with nanoscale fine structures were recorded with a pulsed ˜3 MeV picosecond electron beam. The temporal and spatial resolutions of the MUEM operating in the single-shot mode are about 4 ps (FWHM) and 100 nm (FWHM), corresponding to a temporal-spatial resolution of 4 × 10-19 s m, about 2 orders of magnitude higher than that achieved with state-of-the-art single-shot keV UEM. Using this instrument, we offer the demonstration of visualizing the nanoscale periodic spatial modulation of an electron beam, which may be converted into longitudinal density modulation through emittance exchange to enable production of high-power coherent radiation at short wavelengths. Our results mark a great step towards single-shot nanometer-resolution MUEMs and compact intense x-ray sources that may have widespread applications in many areas of science.

  18. A technique for determining electron losses for a 20 MeV microtron

    International Nuclear Information System (INIS)

    Harisha, P.; Nayak, A.R.; Mehta, S.K.; Soni, H.C.; Siddappa, K.

    1999-01-01

    A 22 orbit, 20 MeV electron microtron is used as a preaccelerator for the 700 MeV booster synchrotron at INDUS-1, CAT, Indore. Estimation of electron losses at the RF cavity from each orbit is important in obtaining the radiation doses from the body of the microtron. Radiation mapping of the microtron can be used to estimate these loss terms as an alternate to actual measurement by using a measuring probe. (author)

  19. Utilization of 5 MeV electron accelerator center and perspective

    International Nuclear Information System (INIS)

    Tanaka, Hiromi

    1990-01-01

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

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

    International Nuclear Information System (INIS)

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

    2005-06-01

    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

  1. 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.

  2. The drive system of 100 MeV electron linear accelerator

    International Nuclear Information System (INIS)

    Sun Yuzhen; Su Guoping; Wang Xiulong; Tianlu

    1988-06-01

    The principle, structure, measurement results and technical performances of microwave drive system for 100MeV electron linear accelerator are presented. In this system the peak power of 15 kW is produced by the S bank middle power klystron. The output power of the klystron is divided into six subdrive lines that drive six high power klystrons respectively. The results show the system with simple structure and good characteristics completely meets the requirements of 100 MeV Linac

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

    International Nuclear Information System (INIS)

    Miller, A.

    2000-01-01

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

  4. RBE comparison between rapid electrons of 20 MeV and 45 MeV with survival rate, DNA synthesis, DNA reparation and nucleoid sedimentation

    International Nuclear Information System (INIS)

    Alth, G.; Weniger, P.; Turtzer, K.; Klein, W.; Kocsis, F.; Krankenhaus der Stadt Wien-Lainz; Oesterreichisches Forschungszentrum Seibersdorf G.m.b.H. Inst. fuer Biologie)

    1982-01-01

    In order to find out possible differences of the biologic efficacy of rapid electrons of different energies, the authors examined the influence of rapid electrons of 20 MeV and 45 MeV upon the survival rate of Hela cells S3, their cell growth, DNA synthesis, DNA reparation, and sedimentation of nucleoids. The results show a difference only for the nucleoid sedimentation, i.e. there are more fractured DNA cords after 45 MeV irradiation. No significant differences could be demonstrated for the parameters of the survival curve, DNA synthesis and DNA reparation. Four double tests were carried out corresponding to the indicated types of examination. (orig.) [de

  5. 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.

  6. Positron-electron decay of 28Si at an excitation energy of 50 MeV

    International Nuclear Information System (INIS)

    Buda, A.; Bacelar, J.C.; Balanda, A.; Ploeg, H. van der; Sujkowski, Z.; Woude, A. van der

    1993-01-01

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

  7. Electron-positron collision physics: 1 MeV to 2 TeV

    International Nuclear Information System (INIS)

    Perl, M.L.

    1988-07-01

    An overview of electron-positron collision physics is presented. It begins at 1 MeV, the energy region of positronium formation, and extends to 2 TeV, the energy region which requires an electron- positron linear collider. In addition, the concept of searching for a lepton-specific forces is discussed. 18 refs., 15 figs., 1 tab

  8. Remarks about a ''parasitic'' 200 MeV electron ring

    International Nuclear Information System (INIS)

    Carlos, P.

    1982-10-01

    The principle of such facility is extremely simple, and consists merely of a set of very thin movable tungsten wires (40 μm < phi < 100 μm) which can be adjusted to intercept a small part of the main linac beam at the center of the BE deflection magnet. Incident electrons are thus scattered in all directions and in particular in the direction of the BE beam transport system, which can be attuned to the average energy of the scattered electrons to send a ''parasitic '' electron beam in the BE experimental area. This parasitic electron beam facility is currently used to operate the low energy tagged photon facility. In order to obtain an intense monochromatic tagged photon beam with a 100% duty cycle a simple procedure is used. It consists of feeding a small stretcher ring equipped with an internal gas jet target with a single electron pulse of width δt delivered every T seconds

  9. The 600 MeV Saclay electron linac: 40000 hour operation

    International Nuclear Information System (INIS)

    Netter, F.

    1977-01-01

    After 40000 hours of operation, the 600 MeV Saclay's electron linac (ALS) does appear as an efficient and versatile tool, for high resolution work (20 μA in ΔE = 40 keV at E = 200MeV), for high power pion production (300 μA in 20 μs pulses at 1000 Hz and 400 MeV or 240 μA in 4 μs pulses at 3000 Hz and 390 MeV), for highly reliable positron beams acceleration, a.s.o. Main improvements made in the recent years are described in particular the automatic beam switching between any two ways among the beam handling system; and the computer newly installed in the control room with a powerful visual display allowing an easy and flexible dialogue of the operators with the computer [fr

  10. 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.

  11. Conceptual design of 30 MeV magnet system used for BNCT epithermal neutron source

    International Nuclear Information System (INIS)

    Slamet Santosa; Taufik

    2015-01-01

    Conceptual design of 30 MeV Magnet System Used for BNCT Epithermal Neutron Source has been done based on methods of empirical model of basic equation, experiences of 13 MeV cyclotron magnet design and personal communications. In the field of health, cyclotron can be used as an epithermal neutron source for Boron Neutron Capture Therapy (BNCT). The development of cyclotron producing epithermal neutrons for BNCT has been performed at Kyoto University, of which it produces a proton beam current of 1.1 mA with energy of 30 MeV. With some experiences on 13 MeV cyclotron magnet design, to support BNCT research and development we performed the design studies of 30 MeV cyclotron magnet system, which is one of the main components of the cyclotron for deflecting proton beam into circular trajectory and serves as beam focusing. Results of this study are expected to define the parameters of particular cyclotron magnet. The scope of this study includes the study of the parameters component of the 30 MeV cyclotron and magnet initial parameters. The empirical method of basic equation model is then corroborated by a simulation using Superfish software. Based on the results, a 30 MeV cyclotron magnet for BNCT neutron source enables to be realized with the parameters of B 0 = 1.06 T, frequency RF = 64.733938 ≈ 65 MHz, the external radius of 0.73 m, the radius of the polar = 0.85 m, BH = 1.95 T and a gap hill of 4 cm. Because proton beam current that be needed for BNCT application is very large, then in the calculation it is chosen a great focusing axial νz = 0.630361 which can generate B V = 0.44 T. (author)

  12. The SLAC polarized electron source

    International Nuclear Information System (INIS)

    Clendenin, J.E.; Alley, R.; Frisch, J.; Kotseroglou, T.; Mulhollan, G.; Schultz, D.; Tang, H.; Turner, J.; Yeremian, A.D.

    1997-08-01

    Since 1992, the SLAC 3-km linac has operated exclusively with polarized electrons. The polarized electron source is highly reliable, remotely operated and monitored, and able to produce a variety of electron bunch profiles for high-energy physics experiments. The source and its operating characteristics are described. Some implications drawn from the operating experience are discussed

  13. A cold atom electron source

    NARCIS (Netherlands)

    Taban, G.

    2009-01-01

    Pulsed bright electron sources offer the possibility to study the structure of matter in great spatial and temporal detail. An example of an indirect method is to generate hard X-ray °ashes with high brilliance, a new Free Electron Laser facility is under construction. It requires an electron source

  14. Photoneutron source based on a compact 10 MeV betatron

    International Nuclear Information System (INIS)

    Chakhlov, V.L.; Bell, Z.W.; Golovkov, V.M.; Shtein, M.M.

    1999-01-01

    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 7 n/s obtained with 1 kg of LiD, 5.7x10 7 n/s from a 3.3 kg Be block, 6.2x10 6 n/s from 1.5 kg of depleted U, and 7.0x10 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

  15. Photoneutron source based on a compact 10 MeV betatron

    International Nuclear Information System (INIS)

    Bell, Z.W.; Chaklov, V.L.; Golovkov, V.M.

    1998-01-01

    Accelerator-based photoneutron sources have enjoyed wide use and offer the advantages of long term stability, ease of control and absence of radioactive materials. The authors report here measurements of the yield of photoneutrons from a neutron generator using a compact betatron (466 kg total weight, 900 by 560 by 350 mm betatron dimensions) at the Institute of Introscopy of the Tomsk Polytechnic University. 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 meter 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 meter flight path perpendicular to the photon beam. The maximum observed yields were 5.2 x 10 4 n/rad/gram target obtained with LiD, 1.7 x 10 4 n/rad/gram from Be, 3.3 x 10 3 n/rad/gram from U, and 7.5 x 10 2 n/rad/gram from Pb. Optimization of target dimensions, shape, and positioning is expected to increase the yield from the LiD target by a factor of 35. With the increased yield, this compact betatron-based system could find application in the interrogation of waste containers for fissile material

  16. Secondary electron emission from metals irradiated by 0.4-3 MeV gamma-quanta

    International Nuclear Information System (INIS)

    Grudskij, M.Ya.; Malyshenkov, A.V.; Smirnov, V.V.

    1975-01-01

    Experimental and calculational data were considered on the secondary electron emission outgoing from metal targets of an equilibrium thickness irradiated by gamma-quanta fluxes with the energies from 0.4 to 3 MeV. New experimental data are presented. Characteristics of emission were measured by two methods: by magnetic spectrometers with a transverse magnetic field, and by means of an electrometric device with using radioisotopic gamma-sources of 198 Au, 137 Cs, 60 Co and 24 Na. The dependence of the electron emission on the atomic number of the target material was studied. For this purpose the parameters of emissions outgoing from Al-, Cu-, Cd-, Pb- and Au-targets were measured. The advantages and shortcomings of the known methods of calculating the second electron emission were discussed. The obtained experimental and calculational results on studying electrons were compared with those known from literature, and possible sources of systematic errors were discussed

  17. 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.

  18. Secondary electron emission from 0.5--2.5-MeV protons and deuterons

    International Nuclear Information System (INIS)

    Thornton, T.A.; Anno, J.N.

    1977-01-01

    Measurement of the secondary electron currents leaving Al, V, Fe, 316 stainless steel, Nb, and Mo foils undergoing 0.5--2.5-MeV proton and deuteron bombardment were made to determine the secondary electron emission ratios for these ions. The measured secondary electron yields were of the order of 1.0, with the deuterons producing generally higher yields than the protons

  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. A sub-picosecond pulsed 5 MeV electron beam system

    International Nuclear Information System (INIS)

    Farrell, J. Paul; Batchelor, K.; Meshkovsky, I.; Pavlishin, I.; Lekomtsev, V.; Dyublov, A.; Inochkin, M.; Srinivasan-Rao, T.

    2001-01-01

    Laser excited pulsed, electron beam systems that operate at energies from 1 MeV up to 5 MeV and pulse width from 0.1 to 100 ps are described. The systems consist of a high voltage pulser and a coaxial laser triggered gas or liquid spark gap. The spark gap discharges into a pulse forming line designed to produce and maintain a flat voltage pulse for 1 ns duration on the cathode of a photodiode. A synchronized laser is used to illuminate the photocathode with a laser pulse to produce an electron beam with very high brightness, short duration, and current at or near the space charge limit. Operation of the system is described and preliminary test measurements of voltages, synchronization, and jitter are presented for a 5 MeV system. Applications in chemistry, and accelerator research are briefly discussed

  1. 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.

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

    Science.gov (United States)

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

    2016-10-01

    We demonstrate laser driven acceleration of electrons at 1 kHz repetition rate with pC charge above 1MeV per shot using required for relativistic self-focusing low enough for mJ scale laser pulses to self- focus and drive strong wakefields. Experiments and particle-in-cell simulations show that optimal drive pulse duration and chirp for maximum electron bunch charge and energy depends on the target gas species. High repetition rate, high charge, and short duration electron bunches driven by very modest pulse energies constitutes an ideal portable electron source for applications such as ultrafast electron diffraction experiments and high rep. rate γ-ray production. This work is supported by the US Department of Energy, the National Science Foundation, and the Air Force Office of Scientific Research.

  3. 7-MeV electron LINAC based pulse radiolysis facility at RPCD, BARC

    International Nuclear Information System (INIS)

    Naik, C.B.; Nadkarni, S.A.; Toley, M.A.; Shinde, S.J.; Naik, P.D.

    2017-01-01

    7-MeV electron LINAC based pulse radiolysis facility is operational in Chemistry Group of BARC since 1986. The Accelerator is housed in B-132 room in basement of Modular Labs. BARC Accelerator was procured from Radiation Dynamics Inc. UK and its detection system was indigenously developed

  4. A measurement of auroral electrons in the 1–10 MeV range

    NARCIS (Netherlands)

    Gils, J.N. van; Beek, H.F. van; Fetter, L.D. de; Hendrickx, R.V.

    Particle fluxes have been measured by means of shielded Geiger-Müller telescopes mounted m a rocket, which was launched from ESRANGE(Kiruna) into a diffuse aurora. The analysis of the dependence of the counting rates on altitude indicates that a weak flux of energetic electrons, 1–10 MeV, has been

  5. Energy distribution of 0. 279 MeV gamma rays Compton scattered from bound electrons

    Energy Technology Data Exchange (ETDEWEB)

    Singh, B; Singh, P; Singh, G; Ghumman, B S

    1984-11-01

    Energy and intensity distribution of 0.279 MeV gamma rays Compton scattered from K-shell electrons of tantalum is measured at scattering angle of 70deg. The experimental results are compared with the available theoretical data. Spectral distribution is also obtained as a function of scatterer thickness to account for the contribution of false events. 13 refs.

  6. 12 MeV, 4.3 kW electron linear accelerator irradiation application

    International Nuclear Information System (INIS)

    Hang Desheng; Lai Qiji

    2000-01-01

    Characteristics of an electron linear accelerator, which has 6-12 MeV energy, 4.2 kW average beam power is introduced. Results show that it has advantages on improving the characteristics of semiconductor devices such as diodes, triodes, SCR, preventing garlic from sprout, preservation of food, and so on

  7. Physics design of a 10 MeV, 6 kW travelling wave electron linac

    Indian Academy of Sciences (India)

    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 π / 3 mode constant impedance travelling wave structure, which ...

  8. 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.

  9. Energy monitoring device for 1.5-2.4 MeV electron beams

    Energy Technology Data Exchange (ETDEWEB)

    Fuochi, P.G., E-mail: fuochi@isof.cnr.i [CNR-ISOF, Via P. Gobetti 101, I-40129 Bologna (Italy); Lavalle, M.; Martelli, A. [CNR-ISOF, Via P. Gobetti 101, I-40129 Bologna (Italy); Kovacs, A. [Institute of Isotopes, HAS, P.O.Box 77, H-1525 Budapest (Hungary); Mehta, K. [Arbeiterstrandbad Strasse 72, Vienna, A-1210 (Austria); Kuntz, F.; Plumeri, S. [Aerial, Parc d' Innovation Rue Laurent Fries F-67400 Illkirch (France)

    2010-03-11

    An easy-to-use and robust energy monitoring device has been developed for reliable detection of day-to-day small variations in the electron beam energy, a critical parameter for quality control and quality assurance in industrial radiation processing. It has potential for using on-line, thus providing real-time information. Its working principle is based on the measurement of currents, or charges, collected by two aluminium absorbers of specific thicknesses (dependent on the beam energy), insulated from each other and positioned within a faraday cup-style aluminium cage connected to the ground. The device has been extensively tested in the energy range of 4-12 MeV under standard laboratory conditions at Institute of Isotopes and CNR-ISOF using different types of electron accelerators; namely, a TESLA LPR-4 LINAC (3-6 MeV) and a L-band Vickers LINAC (7-12 MeV), respectively. This device has been also tested in high power electron beam radiation processing facilities, one equipped with a 7-MeV LUE-8 linear accelerator used for crosslinking of cables and medical device sterilization, and the other equipped with a 10 MeV Rhodotron TT100 recirculating accelerator used for in-house sterilization of medical devices. In the present work, we have extended the application of this method to still lower energy region, i.e. from 1.5 to 2.4 MeV. Also, we show that such a device is capable of detecting deviation in the beam energy as small as 40 keV.

  10. Energy monitoring device for 1.5-2.4 MeV electron beams

    Science.gov (United States)

    Fuochi, P. G.; Lavalle, M.; Martelli, A.; Kovács, A.; Mehta, K.; Kuntz, F.; Plumeri, S.

    2010-03-01

    An easy-to-use and robust energy monitoring device has been developed for reliable detection of day-to-day small variations in the electron beam energy, a critical parameter for quality control and quality assurance in industrial radiation processing. It has potential for using on-line, thus providing real-time information. Its working principle is based on the measurement of currents, or charges, collected by two aluminium absorbers of specific thicknesses (dependent on the beam energy), insulated from each other and positioned within a faraday cup-style aluminium cage connected to the ground. The device has been extensively tested in the energy range of 4-12 MeV under standard laboratory conditions at Institute of Isotopes and CNR-ISOF using different types of electron accelerators; namely, a TESLA LPR-4 LINAC (3-6 MeV) and a L-band Vickers LINAC (7-12 MeV), respectively. This device has been also tested in high power electron beam radiation processing facilities, one equipped with a 7-MeV LUE-8 linear accelerator used for crosslinking of cables and medical device sterilization, and the other equipped with a 10 MeV Rhodotron TT100 recirculating accelerator used for in-house sterilization of medical devices. In the present work, we have extended the application of this method to still lower energy region, i.e. from 1.5 to 2.4 MeV. Also, we show that such a device is capable of detecting deviation in the beam energy as small as 40 keV.

  11. Prognoz 4 observations of electrons accelerated up to energies <=2 MeV and of the cold plasma between the magnetopause and the bow shock

    International Nuclear Information System (INIS)

    Mineev, Yu.V.; Spir'kova, E.S.

    1980-05-01

    The experimental data from Prognoz 4 satellite obtained on a layer of electrons with energies <=2 MeV in the magnetosheath adjacent to magnetopause at different latitudes are given. At moderate latitudes the data are in favour of the leakage of electrons from the outer radiation belt as a source of the layer considered. At high latitudes these electrons apparently arrive along magnetosheath magnetic field lines trapping the magnetopause. (author)

  12. Intensity maps of MeV electrons and protons below the radiation belt

    International Nuclear Information System (INIS)

    Kohno, T.; Munakata, K.; Murakami, H.; Nakamoto, A.; Hasebe, N.; Kikuchi, J.; Doke, T.

    1988-01-01

    The global distributions of energetic electrons (0.19 - 3.2 MeV) and protons (0.64 - 35 MeV) are shown in the form of contour maps. The data were obtained by two sets of energetic particle telescopes on board the satellite OHZORA. The observed altitude range is 350 - 850 Km. Ten degress meshes in longitude and latitude were used to obtain the intensity contours. A pitch angle distribution of J(α) = J(90). sin n α with n = 5 A is assumed to get the average intensity in each mesh. (author) [pt

  13. Evaluation of BPW-34 photodiode answer for 10 MeV electron dosimetry

    International Nuclear Information System (INIS)

    Khoury, H.J.; Melo, F.A.; Hazin, C.A.

    1992-01-01

    The viability of commercial photodiodes used for dosimetry of high energy electron beams was studied. The measures were made in a linear accelerators of 10 MeV, using the BPW-34 photodiode. The average energy of electrons on phantom surface and their average range were determined with the photodiode, and the results were compared with the obtained with a ionization chamber of parallel plate. (C.G.C.)

  14. 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.

  15. Cornell electron beam ion source

    International Nuclear Information System (INIS)

    Kostroun, V.O.; Ghanbari, E.; Beebe, E.N.; Janson, S.W.

    1981-01-01

    An electron beam ion source (EBIS) for the production of low energy, multiply charged ion beams to be used in atomic physics experiments has been designed and constructed. An external high perveance electron gun is used to launch the electron beam into a conventional solenoid. Novel features of the design include a distributed sputter ion pump to create the ultrahigh vacuum environment in the ionization region of the source and microprocessor control of the axial trap voltage supplies

  16. Preliminary design of GDT-based 14 MeV neutron source

    International Nuclear Information System (INIS)

    Du Hongfei; Chen Dehong; Wang Hui; Wang Fuqiong; Jiang Jieqiong; Wu Yican; Chen Yiping

    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/m 2 . (authors)

  17. Calibration of a silicon semiconductor detecter using a 2 MeV electron accelerator beam

    International Nuclear Information System (INIS)

    Fleurot, N.; Gouard, P.; Mazataud, E.; Nail, M.; Savy, C.; Bayer, C.; Cauchois, Y.; Kherouf, R.; Mathieu, D.

    1981-01-01

    This paper describes the current mode calibration, carried out on a 2 MeV electron accelerator, of PIN detectors involved in electron spectrum measurements for laser-matter interaction experiments. A theoretical analysis simulating the interaction between the incident electrons and the irradiated medium has been carried out using the FOTELEC code. It accounts well for the experimental results giving a reasonable value for the mean electron-hole pair formation energy when back-scattering corrections are included. This work provides the transfer function data required for a plasma diagnostic spectrometer. (orig.)

  18. Color centers of a borosilicate glass induced by 10 MeV proton, 1.85 MeV electron and 60Co-γ ray

    Science.gov (United States)

    Du, Jishi; Wu, Jiehua; Zhao, Lili; Song, Lixin

    2013-05-01

    Optical absorption spectra, electron paramagnetic resonance (EPR) spectra, Raman spectra of a borosilicate glass after irradiation by 10 MeV proton, 1.85 MeV electron and 60Co-γ ray were studied. The process of irradiation inducing color centers in the glass was discussed. The band gap of the glass before and after 60Co-γ ray irradiation was studied using Mott and Davis's theory, and it was found that calculated change of the band gap introduced a paradox, because Mott and Davis's theory on the band gap cannot be adopted in the study on the irradiated glass.

  19. The SLC polarized electron source

    International Nuclear Information System (INIS)

    Clendenin, J.E.

    1990-10-01

    A polarized electron source consisting of a 3-electrode photocathode gun and a flashlamp-pumped dye laser has been designed and built for the SLC and is currently undergoing commissioning. The source is described, and the operating configuration is discussed. The present status of the source and future plans are briefly indicated. 7 refs., 4 figs

  20. Thermoluminescence response of Ge-, Al- and Nd- doped optical fibers by 6 MeV - electron and 6 MeV - photon irradiations

    International Nuclear Information System (INIS)

    Hossain, I.; Moburak, A. A.; Saeed, M.A.; Wagiran, H.; Hida, N.; Yaakob, H.N.

    2015-01-01

    In this paper, we report the prediction of thermoluminescence responses of Neodymium-doped SiO 2 optical fibre with various dose ranges from 0.5 Gy to 4.0 Gy by 6 MeV - electron irradiations without requirement for experimental measurements. A technique has been developed to calculate prediction of 6 MeV - electron response of Neodymium-doped SiO 2 optical fibre by observing the measured TL response of 6 MV - photon and the ratio of known measured photon/electron yield ratio distribution for Ge-doped, Al-doped optical fibre and standard TLD 100 dosimeter. The samples were kept in gelatin capsule an irradiated with 6 MV - photon at the dose range from 0.5 Gy to 4.0 Gy. Siemens model Primus 3368 linear accelerator located at Hospital Sultan Ismail, Johor Bahru has been used to deliver the photon beam to the samples. We found the average response ratio of 6 MV - photon and 6 MeV - electron in Ge-doped, Al-doped optical fibre and standard TLD-100 dosimeter are 0.83(3). Observing the measured value of 6 MV - photon irradiation this average ratio is useful to find the prediction of thermoluminescence responses by 6 MeV - electron irradiation of Neodymium-doped SiO 2 optical fibre by the requirement for experimental measurements with various dose ranges from 0.5 Gy to 4.0 Gy by 6 MV - photon irradiations.

  1. Bias dependent charge trapping in MOSFETs during 1 and 6 MeV electron irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Shinde, N.S. [Department of Chemical Engineering, Mie University, 5148507 (Japan); Kulkarni, V.R.; Mathakari, N.L.; Bhoraskar, V.N. [Department of Physics, Univeristy of Pune, Pune 411007 (India); Dhole, S.D. [Department of Physics, Univeristy of Pune, Pune 411007 (India)], E-mail: sanjay@physics.unipune.ernet.in

    2008-06-15

    To study irradiation-induced charge trapping in SiO{sub 2} and around the SiO{sub 2}-Si interface, depletion n-MOSFETs (metal-oxide-semiconductor field effect transistor) were used. The devices were gate biased during 1 and 6 MeV pulsed electron irradiation. The I{sub D}-V{sub DS} (drain current versus drain voltage) and I{sub D}-V{sub GS} (drain current versus gate voltage) characteristics were measured before and after irradiation. The shift in threshold voltage {delta}V{sub T} (difference in threshold voltage V{sub T} before and after irradiation) exhibited trends depending on the applied gate bias during 1 MeV electron irradiation. This behavior can be associated to the contribution of irradiation-induced negative charge {delta}N{sub IT} buildup around the SiO{sub 2}-Si interface to {delta}V{sub T}, which is sensitive to the electron tunneling from the substrates. However, only weak gate bias dependence was observed in 6 MeV electron irradiated devices. Independent of the energy loss and applied bias, the positive oxide trapped charge {delta}N{sub OT} is marginal and can be associated to thin and good quality of SiO{sub 2}. These results are explained using screening of free and acceptor states by the applied bias during irradiation, thereby reducing the total irradiation-induced charges.

  2. Production of iodine-123 radiobiological specimen on 25 MeV electron beam

    International Nuclear Information System (INIS)

    Oganesyan, Yu.Ts.; Starodub, G.Ya.; Buklanov, G.V.; Korotkin, Yu.S.; Belov, A.G.

    1988-01-01

    The technique is described and experimental results are presented for production of radioactive specimen-iodine-123 for medical biological investigations. It is shown that in ten hour irradiation of 124 Xe enriched target of 10 g weight by the 25 MeV electron beam at MT-25 microtron short lived 123 I with activity of about 200 mCl can be accumulated. The procedure was developed for extraction of radioactive atoms and preparing the solution that permits to obtain during 1-1.5 h after the end of irradiation the specimen which satisfies all pharmacopeia requirements. It follows from the results that using small-size electron accelerators with the beam energy up to 25 MeV permits to organize economical and large-scale production of high quality radioactive specimen of 123 I for servicing a large region of this country. 14 refs.; 4 figs.; 1 tab

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

    International Nuclear Information System (INIS)

    Chen Huaibi; Ding Xiaodong; Lin Yuzheng

    2000-01-01

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

  4. Photoreactivity in Saccharomyces cerevisiae cells after irradiation with 25 MeV electrons

    International Nuclear Information System (INIS)

    Tsyb, T.S.; Seleva, N.G.; Myasnik, M.N.; Kabakova, N.M.

    1986-01-01

    Significant photoreactivation was noted in radio- and UV-sensitive rad-mutants of Saccharomyces cerevisiae cells exposed to 25 MeV electrons. In order to make the photoreactivable damage be manifest anoxic conditions of irradiation should be chosen as optimal ones. It was shown that the low oxygen effect was partially associated with the photoreactivable damage involved in the lethal effect of ionizing radiation

  5. Subnanosecond pulsing of an 1 MeV ELIT electron accelerator by beam deflection

    International Nuclear Information System (INIS)

    Vasserman, S.B.; Kuzenko, V.; Mehnert, R.; Hermann, R.

    1984-01-01

    Operation principle and performance of a beam deflection system developed for subnanosecond pulsing of an 1 MeV ELIT resonance transformer accelerator are described. Using this system a minimum pulse duration of 0.5 ns (FWHM) and a dose per pulse of about 20 Gy were obtained. As an example the fluorescence of cyclohexane excited by the subnanosecond electron pulse was measured. (author)

  6. 238U and 237Np nuclear fission by 90-270 MeV electrons

    International Nuclear Information System (INIS)

    Kuznetsov, V.L.; Nedorezov, V.G.; Nikitina, N.V.; Noga, V.I.; Ranyuk, Yu.N.; Telegin, Yu.N.; Smirnov, A.N.; Ehjsmont, V.P.

    1981-01-01

    A technique for measuring cross sections of 238 U and 237 Np nuclei fission caused by 90-270 MeV electrons is described. Measurement results are given. The results obtained are discussed on the basis of the virtual photon method. It is shown that the difference in cross sections of 238 U and 237 Np electrofission is due to the different contribution of the giant resonance [ru

  7. Detection of electrons in the 10 MeV range by plastic scintillators

    Energy Technology Data Exchange (ETDEWEB)

    Beaudoin, G; Champagne, A; Jeremie, H; Lessard, L

    1986-09-10

    Response functions for electrons from 1 to 12 MeV have been measured with a plastic scintillator telescope. A parametrization model for these response functions has been found to give good results at all energies. Furthermore it was established that the type of reflector used for the scintillator has a considerable influence on the response functions. A mechanism for this influence has been proposed and tested by Monte Carlo calculations.

  8. Interplanetary electrons: what is the strength of the Jupiter source

    International Nuclear Information System (INIS)

    Fillius, W.; Ip, Wing-Huen; Knickerbocker, P.

    1977-01-01

    Because there is not enough information to support a rigorous answer, we use a phenomenological approach and conservative assumptions to address the source strength of Jupiter for interplanetary electrons. We estimate that Jupiter emits approximately 10 24 - 10 26 electrons s -1 of energy > 6 MeV, which source may be compared with the population of approximately 3 x 10 28 electrons of the same energy in Jupiter's outer magnetosphere. We conclude that Jupiter accelerates particles at a rate exceeding that of ordinary trapped particle dynamical processes. (author)

  9. The SLAC polarized electron source

    International Nuclear Information System (INIS)

    Tang, H.; Alley, R.; Frisch, J.

    1995-06-01

    The SLAC polarized electron source employs a photocathode DC high voltage gun with a loadlock and a YAG pumped Ti:sapphire laser system for colliding beam experiments or a flash lamp pumped Ti:sapphire laser for fixed target experiments. It uses a thin, strained GaAs(100) photocathode, and is capable of producing a pulsed beam with a polarization of ≥80% and a peak current exceeding 10 A. Its operating efficiency has reached 99%. The physics and technology of producing high polarization electron beams from a GaAs photocathode will be reviewed. The prospects of realizing a polarized electron source for future linear colliders will also be discussed

  10. High-dose MeV electron irradiation of Si-SiO2 structures implanted with high doses Si+

    Science.gov (United States)

    Kaschieva, S.; Angelov, Ch; Dmitriev, S. N.

    2018-03-01

    The influence was studied of 22-MeV electron irradiation on Si-SiO2 structures implanted with high-fluence Si+ ions. Our earlier works demonstrated that Si redistribution is observed in Si+-ion-implanted Si-SiO2 structures (after MeV electron irradiation) only in the case when ion implantation is carried out with a higher fluence (1016 cm-2). We focused our attention on the interaction of high-dose MeV electron irradiation (6.0×1016 cm-2) with n-Si-SiO2 structures implanted with Si+ ions (fluence 5.4×1016 cm-2 of the same order magnitude). The redistribution of both oxygen and silicon atoms in the implanted Si-SiO2 samples after MeV electron irradiation was studied by Rutherford back-scattering (RBS) spectroscopy in combination with a channeling technique (RBS/C). Our results demonstrated that the redistribution of oxygen and silicon atoms in the implanted samples reaches saturation after these high doses of MeV electron irradiation. The transformation of amorphous SiO2 surface into crystalline Si nanostructures (after MeV electron irradiation) was evidenced by atomic force microscopy (AFM). Silicon nanocrystals are formed on the SiO2 surface after MeV electron irradiation. The shape and number of the Si nanocrystals on the SiO2 surface depend on the MeV electron irradiation, while their size increases with the dose. The mean Si nanocrystals height is 16-20 nm after irradiation with MeV electrons at the dose of 6.0×1016 cm-2.

  11. Gamma-ray emission spectra from spheres with 14 MeV neutron source

    International Nuclear Information System (INIS)

    Yamamoto, Junji; Kanaoka, Takeshi; Murata, Isao; Takahashi, Akito; Sumita, Kenji

    1989-01-01

    Energy spectra of neutron-induced gamma-rays emitted from spherical samples were measured using a 14 MeV neutron source. The samples in use were LiF, Teflon:(CF 2 ) n , Si, Cr, Mn, Co, Cu, Nb, Mo, W and Pb. A diameter of the sphere was either 40 or 60 cm. The gamma-ray energy in the emission spectra covered the range from 500 keV to 10 MeV. Measured spectra were compared with transport calculations using the nuclear data files of JENDL-3T and ENDF/B-IV. The agreements between the measurements and the JENDL-3T calculations were good in the emission spectra for the low energy gamma-rays from inelastic scattering. (author)

  12. CESAR, 2 MeV electron storage ring; construction period; general view.

    CERN Multimedia

    Service Photo; CERN PhotoLab

    1962-01-01

    A general view of the 2-MeV electron storage-ring model during the last stages of assembly. The injection line for the electrons enters at the bottom of the picture (under the ladder) and meets the ring at the back, to the right. Near there, Joseph Karouanton (S.G.T.E, Paris) (inside the ring), and Marcel Bernasconi (AR Division) are seen testing for leaks in the vacuum system. In white coats are Mervin Barnes (left) and Boony Bruggerman (AR Division), considering the reading shown by one of the vacuum gauges.

  13. Design and modelling of a 5 MeV radio frequency electron gun

    International Nuclear Information System (INIS)

    Batchelor, K.; Sheehan, J.; Woodle, M.

    1988-01-01

    The Accelerator Test Facility (ATF) at Brookhaven National Laboratory is a linac-laser complex for research into laser acceleration and for the generation of coherent radiation from electron beams. In order to achieve the design 50 MeV output emittance (γσ/sub x/σ/sub x/') of less than 3 /times/ 10/sup /minus/5/ m rad a high brightness electron gun is required. This paper describes computations and measurements made on a full scale brass model of a 1-1/2 cell, π-mode, resonant, disc loaded, radiofrequency gun structure which has been designed for this purpose. 7 refs., 9 figs., 6 tabs

  14. 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)

    1994-12-31

    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.

  15. Diffusion of interstitial atoms in FCC metals after irradiation with 2 MeV electrons

    International Nuclear Information System (INIS)

    Kornmann, H.

    1980-01-01

    Selfdiffusion in nickel after electron irradiation has been restudied. The diffusion velocity near the surface and the diffusion constant in the interior of the crystal have been determined as a function of radiation flux and temperature. A special method for the measurement of diffusion has been improved, which is based on radioactive tracer atoms for indication and on ion etching for the removal of thin films. To improve additionally the accuracy of the technique tracer atoms are induced into the crystal by thermal diffusion and then irradiated with 2 MeV electrons. (orig./GSCH) [de

  16. 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.

  17. 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.).

  18. Measurement of photon showers in lead produced by electrons of 150 MeV

    International Nuclear Information System (INIS)

    Goeringer, H.; Eyss, H.J. von; Schoch, B.

    1976-01-01

    The photon energy spectra induced by 150 MeV electrons in lead were measured in the energy range from 40 MeV up to the primary electron energy. The target thickness was varied between 0.1 and 2.5 radiation lengths X 0 . The photons were analyzed by use of a technique based on deuteron photodisintegration. Differential and integral shower spectra are presented and compared with Monte Carlo calculations of Nagel and Messel et al., both interpolated to our primary energy of 150 MeV. The measured spectra show good agreement with these Monte Carlo calculations for the thickest target of 2.5X 0 and with calculated bremsstrahlung spectra for the thinnest target of 0.1X 0 . Considerable discrepancies, however, are found for medium target thicknesses in the range 0 . Around the shower maxima, the shower spectra are narrower and the maxima are shifted about 0.3-0.4X 0 to lower target thicknesses, furthermore the number of photons at the shower maxima are up to 50% higher than calculated. (Auth.)

  19. Beam plasma 14 MeV neutron source for fusion materials development

    International Nuclear Information System (INIS)

    Ravenscroft, D.; Bulmer, D.; Coensgen, F.; Doggett, J.; Molvik, A.; Souza, P.; Summers, L.; Williamson, V.

    1991-09-01

    The conceptual engineering design and expected performance for a 14 MeV DT neutron source is detailed. The source would provide an intense neutron flux for accelerated testing of fusion reactor materials. The 150-keV neutral beams inject energetic deuterium atoms, that ionize, are trapped, then react with a warm (200 eV), dense tritium target plasma. This produces a neutron source strength of 3.6 x 10 17 n/sec for a neutron power density at the plasma edge of 5--10 MW/m 2 . This is several times the ∼2 MW/m 2 anticipated at the first wall of fusion reactors. This high flux provides accelerated end-of-life tests of 1- to 2-year duration, thus making materials development possible. The modular design of the source and the facilities are described

  20. New source of MeV negative ion and neutral atom beams

    Energy Technology Data Exchange (ETDEWEB)

    Ter-Avetisyan, S., E-mail: sargis@gist.ac.kr [Center for Relativistic Laser Science, Institute for Basic Science (IBS), Gwangju 500-712 (Korea, Republic of); Department of Physics and Photon Science, GIST, Gwangju 500-712 (Korea, Republic of); Braenzel, J.; Schnürer, M. [Max Born Institute for Nonlinear Optics and Short Pulse Spectroscopy, Berlin 12489 (Germany); Prasad, R. [Institute for Laser and Plasma Physics, Heinrich Heine University, Duesseldorf 40225 (Germany); Borghesi, M. [School of Mathematics and Physics, The Queen’s University of Belfast, Belfast BT7-1NN (United Kingdom); Jequier, S.; Tikhonchuk, V. [Centre Lasers Intenses et Applications, CEA, CNRS, University of Bordeaux, 33405 Talence (France)

    2016-02-15

    The scenario of “electron-capture and -loss” was recently proposed for the formation of negative ion and neutral atom beams with MeV kinetic energies. However, it does not explain why the formation of negative ions in a liquid spray is much more efficient than with an isolated atom. The role of atomic excited states in the charge-exchange processes is considered, and it is shown that it cannot account for the observed phenomena. The processes are more complex than the single electron-capture and -loss approach. It is suggested that the shell effects in the electronic structure of the projectile ion and/or target atoms may influence the capture/loss probabilities.

  1. New source of MeV negative ion and neutral atom beams

    International Nuclear Information System (INIS)

    Ter-Avetisyan, S.; Braenzel, J.; Schnürer, M.; Prasad, R.; Borghesi, M.; Jequier, S.; Tikhonchuk, V.

    2016-01-01

    The scenario of “electron-capture and -loss” was recently proposed for the formation of negative ion and neutral atom beams with MeV kinetic energies. However, it does not explain why the formation of negative ions in a liquid spray is much more efficient than with an isolated atom. The role of atomic excited states in the charge-exchange processes is considered, and it is shown that it cannot account for the observed phenomena. The processes are more complex than the single electron-capture and -loss approach. It is suggested that the shell effects in the electronic structure of the projectile ion and/or target atoms may influence the capture/loss probabilities

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

    International Nuclear Information System (INIS)

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

    2016-01-01

    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.

  3. Number transmission of 0.6 and 0.8MeV electrons in elemental materials

    International Nuclear Information System (INIS)

    Harami, Taikan; Takagaki, Torao; Matsuda, Koji; Nakai, Yohta.

    1975-01-01

    The number transmissions of electrons in Be, Al, Cu and Ag were obtained experimentally for well collimated electron beams of 0.6 and 0.8 MeV. Experimental results of the present work join smoothly to the previous ones of 1.0 MeV to 2.0 MeV electrons. The ratios of extrapolated range Rsub(ex) to true range R 0 give generally minimum values near 1 MeV (approximately 2mc 2 ) as well as the stopping power. An investigation was done for empirical equation of the form eta=exp(-xP/CEsup(m)), where E is the incident electron energy, x, penetration depth, and p, C and m are the parameters determined from experimental data. (author)

  4. Lithium Blanket Module dosimetry measurements at the LOTUS 14-MeV neutron source facility

    International Nuclear Information System (INIS)

    Tsang, F.Y.; Leo, W.R.; Sahraoui, C.; Wuthrich, S.; Harker, Y.D.

    1986-01-01

    This paper describes the measurements and results of the dosimeter material reaction rates inside the Lithium Blanket Module (LBM) after irradiation by the LOTUS 14-MeV neutron source at the Ecole Polytechnique Federale de Lausanne. The measurement program has been designed to utilize sets of passive dosimeter materials in the form of foils and wires. The dosimetry materials reaction thresholds and interaction response ranges chosen for this series of measurements encompass the entire neutron spectra along the full length of the LBM fuel rods

  5. Study of interactions of a electron beam of 10 MeV energy and matter

    International Nuclear Information System (INIS)

    Askri, Boubaker

    2002-01-01

    In this work, we tried to extend the algorithm of the Monte Carlo method to the case of relativistic electrons of energy 10 MeV through the material, after appropriate to the simple case of non-relativistic electrons of energy 20 keV. It was determined the coefficients of reflection, transmission and absorption of electrons through the middle in both cases. As the energy and angular distributions of electrons transmitted. The results show a fairly good precision on the determination of the three coefficients. For the non-relativistic case, it was in 1000 simulations of 1000 lots electrons for gold and aluminum, it has reached an accuracy of about 0.5 pour cent. For the relativistic case, it was 20 lots of simulations for 500 electrons carbon and aluminum. we reached an accuracy of about 2, 5 pour cent determining the coefficients. The energy and angular distributions of electrons transmitted, are close those derived from the program GEANT, taken as a reference and as comparison tool. It hopes to increase the accuracy by increasing the number of lots and the size of each batch of electrons. However, the process took six days to simulate ten miles electrons under normal conditions on the HP9000 machine calculation takes a greatest time of execution for a statistical sample of smaller great. Several criteria are necessary to optimize the study. About improving the theoretical model and the algorithm, and implementation the procedure on a machine more powerful computing. (Author)

  6. Lateral propagation of MeV electrons generated by femtosecond laser irradiation

    International Nuclear Information System (INIS)

    Seely, J. F.; Szabo, C. I.; Audebert, P.; Brambrink, E.; Tabakhoff, E.; Hudson, L. T.

    2010-01-01

    The propagation of MeV electrons generated by intense (≅10 20 W/cm 2 ) femtosecond laser irradiation, in the lateral direction perpendicular to the incident laser beam, was studied using targets consisting of irradiated metal wires and neighboring spectator wires embedded in electrically conductive (aluminum) or resistive (Teflon) substrates. The K shell spectra in the energy range 40-60 keV from wires of Gd, Dy, Hf, and W were recorded by a transmission crystal spectrometer. The spectra were produced by 1s electron ionization in the irradiated wire and by energetic electron propagation through the substrate material to the spectator wire of a different metal. The electron range and energy were determined from the relative K shell emissions from the irradiated and spectator wires separated by varying substrate lateral distances of up to 1 mm. It was found that electron propagation through Teflon was inhibited, compared to aluminum, implying a relatively weak return current and incomplete space-charge neutralization. The energetic electron propagation in the direction parallel to the electric field of the laser beam was larger than perpendicular to the electric field. Energetic electron production was lower when directly irradiating aluminum or Teflon compared to irradiating the heavy metal wires. These experiments are important for the determination of the energetic electron production mechanism and for understanding lateral electron propagation that can be detrimental to fast-ignition fusion and hard x-ray backlighter radiography.

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

    International Nuclear Information System (INIS)

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

    2005-01-01

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

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

    International Nuclear Information System (INIS)

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

    2015-01-01

    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 D 10 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. - Highlights: • 10 MeV eBeam energy was attenuated to 2.9±0.22 MeV using HDPE sheets. • Attenuation of eBeam energy does not affect the inactivation kinetics of Salmonella. • Microbial inactivation is independent of eBeam energy in the range of 3–10 MeV

  9. Color centers of a borosilicate glass induced by 10 MeV proton, 1.85 MeV electron and 60Co-γ ray

    International Nuclear Information System (INIS)

    Du, Jishi; Wu, Jiehua; Zhao, Lili; Song, Lixin

    2013-01-01

    Optical absorption spectra, electron paramagnetic resonance (EPR) spectra, Raman spectra of a borosilicate glass after irradiation by 10 MeV proton, 1.85 MeV electron and 60 Co-γ ray were studied. The process of irradiation inducing color centers in the glass was discussed. The band gap of the glass before and after 60 Co-γ ray irradiation was studied using Mott and Davis's theory, and it was found that calculated change of the band gap introduced a paradox, because Mott and Davis's theory on the band gap cannot be adopted in the study on the irradiated glass. - Highlights: ► All the three types of irradiation induce the same types of color centers. ► Calculated change of the band gap introduced a paradox. ► Mott and Davis's theory on band gap cannot be adopted in the irradiated glass

  10. 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...... 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...

  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. Microdosimetry of 0.5 to 2.0 MeV electron beams

    International Nuclear Information System (INIS)

    Braby, L.A.; Roesch, W.C.

    1980-08-01

    The energy imparted in microscopic volumes by electron beams with initial energies from 0.5 to 2.0 MeV has been measured at various depths in plastic. The problems associated with measuring energy deposition spectra of low LET radiations are serious, but the potential importance of these measurements in radiation biophysics justifies the effort required to obtain them. Recent results obtained by Goodhead et al. indicate an RBE greater than 2 for 0.3 keV x-rays compared to 250 kV x-rays, and our results with Chlamydomonas reinhardi indicate an RBE of 1.6 for a 1.5 MeV electron beam at a depth of 400 gm/cm 2 in lucite compared to the same beam at the surface. Development of a theory which appears to explain these results in terms of the microscopic distribution of energy deposition has motivated a detailed study of energy deposition spectra for an electron beam attenuated by various thicknesses of lucite. Simulated sites from 0.5 to 1.9 μm in diameter were studied. The values of anti y determined in these single event measurements compare favorably with those calculated from direct measurements of z reported previously. As expected, the means of the distributions increase significantly with increasing depth in an absorber

  13. Study of imaging plate detector sensitivity to 5-18 MeV electrons

    Energy Technology Data Exchange (ETDEWEB)

    Boutoux, G., E-mail: boutoux@celia.u-bordeaux1.fr; Rabhi, N.; Batani, D.; Ducret, J.-E. [Univ. de Bordeaux, CNRS, CEA, CELIA (Centre Lasers Intenses et Applications), UMR 5107, F-33405 Talence (France); Binet, A.; Nègre, J.-P.; Reverdin, C.; Thfoin, I. [CEA DAM DIF, F-91297 Arpajon (France); Jakubowska, K. [Institute of Plasma Physics and Laser Microfusion, Hery Street 23, 01-497 Warsaw (Poland)

    2015-11-15

    Imaging plates (IPs) are commonly used as passive detectors in laser-plasma experiments. We calibrated at the ELSA electron beam facility (CEA DIF) the five different available types of IPs (namely, MS-SR-TR-MP-ND) to electrons from 5 to 18 MeV. In the context of diagnostic development for the PETawatt Aquitaine Laser (PETAL), we investigated the use of stacks of IP in order to increase the detection efficiency and get detection response independent from the neighboring materials such as X-ray shielding and detector supports. We also measured fading functions in the time range from a few minutes up to a few days. Finally, our results are systematically compared to GEANT4 simulations in order to provide a complete study of the IP response to electrons over the energy range relevant for PETAL experiments.

  14. Numerical simulation of electrons dynamics in a microtron on 6 - 10 MeV

    Science.gov (United States)

    Bashmakov, Y. A.; Dyubkov, V. S.; Lozeev, Y. Y.

    2017-12-01

    Electron dynamics in 6.5 MeV classic microtron of the Lebedev Physics Institute (LPI) is investigated by means of numerical methods. Particular emphasis is placed on the formation mechanism of electron bunches at the first circular orbits. An effect of microtron main parameters such as accelerating RF field amplitude, DC magnetic field, as well as a geometry and a position of a thermal emitter on characteristics of electron beam extracted from the microtron are studied. In the space of mentioned parameters a region corresponding an optimal microtron operation mode is found. It is noted that the unique geometric and energy characteristics of accelerated beam makes use of microtron attractive not only as injector into a synchrotron, but also as a driver in experiments on generation of coherent terahertz electromagnetic radiation.

  15. Electron and ion currents relevant to accurate current integration in MeV ion backscattering spectrometry

    International Nuclear Information System (INIS)

    Matteson, S.; Nicolet, M.A.

    1979-01-01

    The magnitude and characteristics of the currents which flow in the target and the chamber of an MeV ion backscattering spectrometer are examined. Measured energy distributions and the magnitude of high-energy secondary electron currents are reported. An empirical universal curve is shown to fit the energy distribution of secondary electrons for several combinations of ion energy, targets and ion species. The magnitude of tertiary electron currents which arise at the vacuum vessel walls is determined for various experimental situations and is shown to be non-negligible in many cases. An experimental arrangement is described which permits charge integrations to 1% arruracy without restricting access to the target as a Faraday cage does. (Auth.)

  16. Analysis of thermionic DC electron gun for 125 MeV linac

    International Nuclear Information System (INIS)

    Kanno, K.; Sato, Isamu; Sato, K.

    2000-01-01

    The beam trace calculation for the 100 kV thermionic DC electron gun with EIMAC 646E cathode, which is currently used for the 125 MeV linac at Nihon University, has been performed using EGUN code. The result showed a strong focus of the beam at the exit of the anode. A better geometry of the gun has been investigated by varying the shape of the wehnelt electrode. Also the trace calculation has been performed for the case of EIMAC 646B, which showed a considerably small emittance compared with that estimated for the present gun. (author)

  17. Analysis of thermionic DC electron gun for 125 MeV linac

    Energy Technology Data Exchange (ETDEWEB)

    Kanno, K. [Graduate School of Science and Technology, Nihon Univ., Funabashi, Chiba (Japan); Sato, Isamu; Sato, K. [Nihon Univ., Funabashi, Chiba (Japan). Atomic Energy Research Inst] [and others

    2000-07-01

    The beam trace calculation for the 100 kV thermionic DC electron gun with EIMAC 646E cathode, which is currently used for the 125 MeV linac at Nihon University, has been performed using EGUN code. The result showed a strong focus of the beam at the exit of the anode. A better geometry of the gun has been investigated by varying the shape of the wehnelt electrode. Also the trace calculation has been performed for the case of EIMAC 646B, which showed a considerably small emittance compared with that estimated for the present gun. (author)

  18. Radiation from 39 and 45 MEV electrons channeled in lithium niobate

    Energy Technology Data Exchange (ETDEWEB)

    Diedrich, E.; Kufner, W.; Buschhorn, G. (Max-Planck-Institut fuer Physik und Astrophysik, Muenchen (Germany). Werner-Heisenberg-Inst. fuer Physik)

    1991-12-01

    Channeling radiation from 39 and 45 MeV electrons channeled along the (0001) axis, the (0110) plane and the (1210) plane of a 30 {mu}m thick LiNbO{sub 3} crystal has been measured. Calculations of the planar crystal potentials were performed by means of the many-beam formalism. Good agreement between theory and experiment is obtained for the planar channeling radiation. Associated with channeling, additional radiation lines have been observed, which may be explained by a periodic perturbation of the continuum potential. (author).

  19. Optimization calculations for slow neutron production with the 136 MeV Harwell electron linac

    International Nuclear Information System (INIS)

    Needham, J.; Sinclair, R.N.

    1978-10-01

    The new 136 MeV Harwell electron linac is to be used to produce pulsed beams of slow neutrons for condensed matter research. Design details and performance of the two types of moderator which will be available have been optimised using a Monte Carlo neutronics code (TIMOC). The choice of reflector, the necessary decoupling energy to prevent pulse broadening and the influence of γ shields and moderator shape have been investigated. The predicted yield of leakage neutrons of energy 1 eV is compared to published values for comparable facilities. (author)

  20. 5 MeV 300 kW electron accelerator project

    International Nuclear Information System (INIS)

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

    2004-01-01

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

  1. Beam diagnostics using transition radiation produced by a 100 Mev electron beam

    International Nuclear Information System (INIS)

    Jablonka, M.; Leroy, J.; Hanus, X.; Derost, J.C.; Wartski, L.

    1991-01-01

    We report on several experiments using the optical transition radiation (OTR) produced by a 100 MeV electron beam. In using a sensitive video camera coupled with a digital image processing system an accurate and simple beam profile monitor has been devised. In measuring with a photo-multiplier the radiation emitted in a small solid angle around the direction of the OTR emission, a signal very sensitive to beam energy variations has been obtained. These experiments have been carried out on the Saclay ALS linac

  2. 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.

  3. 6 MeV pulsed electron beam induced surface and structural changes in polyimide

    Energy Technology Data Exchange (ETDEWEB)

    Mathakari, Narendra L.; Bhoraskar, Vasant N. [Microtron Accelerator Laboratory, Department of Physics, University of Pune, Ganeshkhind, Pune 411007, Maharashtra (India); Dhole, Sanjay D., E-mail: sanjay@physics.unipune.ernet.i [Microtron Accelerator Laboratory, Department of Physics, University of Pune, Ganeshkhind, Pune 411007, Maharashtra (India)

    2010-04-15

    Thin films of polyimide (PMDA-ODA, Kapton) having 50 mum thickness were irradiated with 6 MeV pulsed electron beam. The bulk and surface properties of pristine and irradiated samples were characterized by several techniques such as stress-strain measurements, Fourier Transform Infrared (FTIR), UV-vis spectroscopy, contact angle, atomic force microscopy (AFM) and profilometry. The tensile strength, percentage elongation and strain energy show an enhancement from pristine value of 73-89 MPa, 10-22% and 4.75-14.2 MJ/m{sup 3} respectively at the maximum fluence of 4 x 10{sup 15} electrons/cm{sup 2}. This signifies that polyimide being an excessively aromatic polymer is crosslinked due to high-energy electron irradiation. In surface properties, the contact angle shows a significant decrease from 59 deg. to 32 deg. indicating enhancement in hydrophilicity. This mainly attributes to surface roughening, which is due to the electron beam induced sputtering. The surface roughening is confirmed in AFM and profilometry measurements. The AFM images clearly show that surface roughness increases after electron irradiation. Moreover, the roughness average (R{sub a}) as measured from surface profilograms is found to increase from 0.06 to 0.1. The FTIR and UV-vis spectra do not show noticeable changes as regards to scissioning of bonds and the oxidation. This work leads to a definite conclusion that 6 MeV pulsed electron beam can be used to bring about desired changes in surface as well as bulk properties of polyimide, which is considered to be a high performance space quality polymer.

  4. 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.

  5. Design of 6 MeV X-band electron linac for dual-head gantry radiotherapy system

    Science.gov (United States)

    Shin, Seung-wook; Lee, Seung-Hyun; Lee, Jong-Chul; Kim, Huisu; Ha, Donghyup; Ghergherehchi, Mitra; Chai, Jongseo; Lee, Byung-no; Chae, Moonsik

    2017-12-01

    A compact 6 MeV electron linac is being developed at Sungkyunkwan University, in collaboration with the Korea atomic energy research institute (KAERI). The linac will be used as an X-ray source for a dual-head gantry radiotherapy system. X-band technology has been employed to satisfy the size requirement of the dual-head gantry radiotherapy machine. Among the several options available, we selected a pi/2-mode, standing-wave, side-coupled cavity. This choice of radiofrequency (RF) cavity design is intended to enhance the shunt impedance of each cavity in the linac. An optimum structure of the RF cavity with a high-performance design was determined by applying a genetic algorithm during the optimization procedure. This paper describes the detailed design process for a single normal RF cavity and the entire structure, including the RF power coupler and coupling cavity, as well as the beam dynamics results.

  6. Evolution of defects in a multicomponent glass irradiated by 1 MeV electrons

    International Nuclear Information System (INIS)

    Wang Qingyan; Geng Hongbin; Sun Chengyue; Zhang Zhonghua; He Shiyu

    2010-01-01

    The optical properties and microstructural degradation of a multicomponent glass after exposure to 1 MeV electrons for fluences of 10 13 to 10 16 e - /cm 2 , as well as the recovery during annealing at room temperature (RT) for the fluence of 10 16 e - /cm 2 , are investigated. The non-bridging oxygen hole centers (NBOHCs), as well as trapped electrons (TEs), are mainly attributed to optical absorption bands and paramagnetic spectra. In comparison of the exponential curves, the in-growth kinetics for each type of defect with increasing fluence are separable, and a new linearly-combined exponential model is used to describe the structural responses during irradiation. Accordingly, RT bleaching curves of defects follow a linearly-combined exponential decay function. Consistent results from optical and paramagnetic signals suggest that this linearly-combined model provides a reasonable kinetic description of the growth and bleaching process of defects.

  7. Simulation of energy deposit distribution in water for 10 and 25 MeV electron beams

    International Nuclear Information System (INIS)

    Borrell Carbonell, Maria de los Angeles.

    1977-01-01

    The Monte Carlo method was applied to transport simulation of electron beams from the exit window of a linear accelerator till the absorption by a water phantom. The distribution of energy deposit is calculated for ideal apparatus and experimental conditions. Calculations are made for a distance window-water surface of one meter, for 10 and 25 MeV monoenergetic incident electrons, and for different fields (15x15 cm 2 to 4x4 cm 2 ). Comparisons with experimental measurements obtained in comparable conditions with a Sagittaire accelerator (C.G.R.-MeV), show a good agreement concerning radial distribution and depth distribution around isodose 100%. However a certain disagreement appears in the end of depth penetration [fr

  8. Radiation damage of silicon structures with electrons of 900 MeV

    CERN Document Server

    Rachevskaia, I; Bosisio, L; Dittongo, S; Quai, E; Rizzo, G

    2002-01-01

    We present first results on the irradiation of double-sided silicon microstrip detectors and test structures performed at the Elettra synchrotron radiation facility at Trieste, Italy. The devices were irradiated with 900 MeV electrons. The test structures we used for studying bulk, surface and oxide irradiation damage were guard ring diodes, gated diodes and MOS capacitors. The test structures and the double-sided microstrip detectors were produced by Micron Semiconductor Ltd. (England) and IRST (Trento, Italy). For the first time, bulk-type inversion is observed to occur after high-energy electron irradiation. Current and inter-strip resistance measurements performed on the microstrip detectors show that the devices are still usable after type inversion.

  9. High Intensity Polarized Electron Sources

    International Nuclear Information System (INIS)

    Poelker, Benard; Adderley, Philip; Brittian, Joshua; Clark, J.; Grames, Joseph; Hansknecht, John; McCarter, James; Stutzman, Marcy; Suleiman, Riad; Surles-law, Kenneth

    2008-01-01

    During the 1990s, at numerous facilities world wide, extensive RandD devoted to constructing reliable GaAs photoguns helped ensure successful accelerator-based nuclear and high-energy physics programs using spin polarized electron beams. Today, polarized electron source technology is considered mature, with most GaAs photoguns meeting accelerator and experiment beam specifications in a relatively trouble-free manner. Proposals for new collider facilities however, require electron beams with parameters beyond today's state-of-the-art and serve to renew interest in conducting polarized electron source RandD. And at CEBAF/Jefferson Lab, there is an immediate pressing need to prepare for new experiments that require considerably more beam current than before. One experiment in particular?Q-weak, a parity violation experiment that will look for physics beyond the Standard Model?requires 180 uA average current at polarization >80% for a duration of one year, with run-averaged helicity correlate

  10. Product conveying system for 10 MeV electron beam accelerator for electron beam centre, Kharghar, Navi Mumbai

    International Nuclear Information System (INIS)

    Bandi, L.N.; Lavale, D.S.; Sarma, K.S.S.; Khader, S.A.; Assadullah, M.; Sabharwal, S.

    2003-01-01

    In industrial radiation processing applications using accelerators, product conveying system plays a vital role in exposing the product to high energy electron beam for imparting specified dose to the product and delivering required through puts. The speed of the conveyor corresponds to a definite time of exposure of the product in the radiation zone. Design of suitable conveyor system for a variety of products with differing dose requirements call for a conveyor with wide speed range. This paper discusses the design features of a suitable under beam conveyor system for 10 MeV, 10 kW accelerator for processing a range of products including medical and food products

  11. Multipurpose intense 14 MeV neutron source at Bratislava: Design study

    International Nuclear Information System (INIS)

    Pivarc, J.; Hlavac, S.; Kral, J.; Oblozinsky, P.; Ribansky, I.; Turzo, I.

    1980-05-01

    The present state of design of the multipurpose intense 14 MeV neutron source based on a D + ion beam and a metal tritide target is reported. It is essentially a 300 keV electrostatic air insulated accelerator capable to accelerate a deuterium ion beam up to 10 mA. With such a beam and a beam spot of 1 cm 2 , a neutron yield typically 10 12 n/s and a useful target lifetime of around 10 h are expected. Various users requirements are met by means of three beam lines: an intense, low current dc and a low current fast pulsed. The key components of the intense source section are the rotating target and the ion source. The rotating target is proposed, with respect of the heat dissipation and the removal of 3 kW/cm 2 , in continuous operation. A rotation speed up to 1100 rpm is considered. The ion source should deliver about 0.5 kW of extracted D + ion beam power. A duoplasmatron source with an electrostatic beam focusing system has been selected. Low current sections of the neutron source may operate with a high frequency ion source as well. The dc section for maximum yields around 10 10 n/s is designed with special regard to beam monitoring. The fast pulsed section should produce up to 1 ns compressible pulsed D + ion beam on a target spot with 5 MHz repetition rate. The report includes information about other components of the neutron source as a high voltage power supply, a vacuum system, beam transport, a diagnostic and control system and basic information about neutron source cells and radiation protection. (author)

  12. Design of 6 Mev linear accelerator based pulsed thermal neutron source: FLUKA simulation and experiment

    Energy Technology Data Exchange (ETDEWEB)

    Patil, B.J., E-mail: bjp@physics.unipune.ac.in [Department of Physics, University of Pune, Pune 411 007 (India); Chavan, S.T.; Pethe, S.N.; Krishnan, R. [SAMEER, IIT Powai Campus, Mumbai 400 076 (India); Bhoraskar, V.N. [Department of Physics, University of Pune, Pune 411 007 (India); Dhole, S.D., E-mail: sanjay@physics.unipune.ac.in [Department of Physics, University of Pune, Pune 411 007 (India)

    2012-01-15

    The 6 MeV LINAC based pulsed thermal neutron source has been designed for bulk materials analysis. The design was optimized by varying different parameters of the target and materials for each region using FLUKA code. The optimized design of thermal neutron source gives flux of 3 Multiplication-Sign 10{sup 6}ncm{sup -2}s{sup -1} with more than 80% of thermal neutrons and neutron to gamma ratio was 1 Multiplication-Sign 10{sup 4}ncm{sup -2}mR{sup -1}. The results of prototype experiment and simulation are found to be in good agreement with each other. - Highlights: Black-Right-Pointing-Pointer The optimized 6 eV linear accelerator based thermal neutron source using FLUKA simulation. Black-Right-Pointing-Pointer Beryllium as a photonuclear target and reflector, polyethylene as a filter and shield, graphite as a moderator. Black-Right-Pointing-Pointer Optimized pulsed thermal neutron source gives neutron flux of 3 Multiplication-Sign 10{sup 6} n cm{sup -2} s{sup -1}. Black-Right-Pointing-Pointer Results of the prototype experiment were compared with simulations and are found to be in good agreement. Black-Right-Pointing-Pointer This source can effectively be used for the study of bulk material analysis and activation products.

  13. Optimization of beam parameters of electron gun for 2.5 MeV/100 kW high power industrial accelerator

    International Nuclear Information System (INIS)

    Pramod, R.; Petwal, V.C.

    2009-01-01

    A 2.5 MeV/100 kW transformer type industrial accelerator is being developed at RRCAT. A Pierce type electron gun consisting of 10 mm diameter LaB 6 disc (indirectly heated) is used as a source of electron beam. The cathode assembly is put on the top of the accelerating structure, which consists of many electrostatic lenses of which the first lens acts as anode of the gun. The quality of the beam injected into the accelerating structure depends on the anode voltage, shape and size of anode and its distance from the cathode. The anode is subjected to variable voltage during the operation of accelerator from energy 1 MeV to 2.5 MeV, which results in variable emittance at the exit of the electron gun. The electron beam from the gun should provide parallel or slightly convergent beam with long focal length and the emittance of the beam at the exit of electron gun should match the beam acceptance limit of the accelerating structure. The EGUN code is used to optimize the shape and size of the anode, its distance from the cathode to achieve above objectives. Our study suggests that the desired beam parameters at the exit of the anode can be obtained by reducing the aperture size of the anode and by applying suitable voltage gradient to the anode. (author)

  14. Laser-Electron-Gamma-Source. Progress report, July 1986

    International Nuclear Information System (INIS)

    Dowell, D.H.; Fineman, B.; Giordano, G.; Kistner, OC.; Matone, G.; Sandorfi, A.M.; Schaerf, C.; Thorn, C.E.; Ziegler, W.

    1986-07-01

    When completed, the Laser Electron Gamma Source (LEGS) is expected to provide intense beams of monochromatic and polarized (circular or linear) gamma rays with energies up to 500 MeV. The gamma-ray beams will be produced by Compton backscattering uv laser light from the electrons circulating in a storage ring. Progress with installation of the facility is described, particularly the Ar-ion laser and tagging spectrometer. Tests of the tagging spectrometer coponents is reported, and a second laser is described for higher energy operation. Estimates are given of expected beam parameters. Experimental equipment for the planned research projects to be carried out at the LEGS facility is discussed

  15. MeV energy electron beam induced damage in isotactic polypropylene

    Energy Technology Data Exchange (ETDEWEB)

    Mathakari, N.L.; Bhoraskar, V.N. [Microtron Accelerator Laboratory, Department of Physics, University of Pune, Pune 411007 (India); Dhole, S.D. [Microtron Accelerator Laboratory, Department of Physics, University of Pune, Pune 411007 (India)], E-mail: sanjay@physics.unipune.ernet.in

    2008-06-15

    A few thin films of isotactic polypropylene were irradiated with 6 MeV energy electrons, in the fluence range from 5 x 10{sup 14} to 2 x 10{sup 15} electrons/cm{sup 2}. The structural, optical and mechanical properties were characterized by techniques such as FTIR, UV-vis, XRD, SEM, hardness and contact angle measurements. The FTIR spectra indicate that C-H and C-C bonds are scissioned and an isotactic arrangement of chains is partially destroyed. Moreover, the new carbonyl groups (C=O) are observed, which signifies oxidation. The UV-vis spectra shows a red shift in the absorption edge from pristine value of 240 to 380 nm, which corresponds to decrease in the optical band gap from 5.17 to 3.27 eV. This is because of the formation of conjugated double bonds as well as carbonization. The crystalline properties were analysed using XRD and it shows no profound change. This result may attribute that the radiation-induced changes have probably occurred to a large extent in amorphous regions. However, surface morphology by SEM and contact angle measurements showed considerable surface roughening, which indicates an uneven evolution of gases from the surface. Interestingly, the surface hardness of the films was found to increase with fluence and it may be due to crosslinking and carbonization on the surface. Overall, in conclusion this study shows considerable modifications in the physicochemical properties of isotactic polypropylene irradiated by 6 MeV energy pulsed electrons.

  16. 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 ...

  17. Design of scan-horn and beam extraction window for a 3 MeV electron accelerator

    International Nuclear Information System (INIS)

    Ghodke, S.R.; Acharya, S.; Puthran, G.P.; Majumder, R.; Mittal, K.C.; Mahendra Kumar; Sethi, R.C.

    2003-01-01

    A 3 MeV, 30 kW D.C. electron accelerator is being developed for installation at the Electron Beam Center at Khargar, Navi Mumbai to cater to industrial uses like cable irradiation. This paper describes the design of the scan horn and beam extraction window of this accelerator. (author)

  18. 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...

  19. Number distribution of emitted electrons by MeV H+ impact on carbon

    Science.gov (United States)

    Ogawa, H.; Koyanagi, Y.; Hongo, N.; Ishii, K.; Kaneko, T.

    2017-09-01

    The statistical distributions of the number of the forward- and backward-emitted secondary electrons (SE's) from a thin carbon foil have been measured in coincidence with foil-transmitted H+ ions of 0.5-3.0 MeV in every 0.5 MeV step. The measured SE energy spectra were fitted by assuming a Pólya distribution for the simultaneous n-SE emission probabilities. For our previous data with a couple of the carbon foils with different thicknesses, a similar analysis has been carried out. As a result, it was found that the measured spectra could be reproduced as well as by an analysis without placing any restriction on the emission probabilities both for the forward and backward SE emission. The obtained b-parameter of the Pólya distribution, which is a measure of the deviation from a Poisson distribution due to the cascade multiplication by high energy internal SE's, increases monotonically with the incident energy of proton beams. On the other hand, a clear foil-thickness dependence is not observed for the b-parameter. A theoretical model which could reproduced the magnitude of the b-parameter for the SE energy spectra obtained with thick Au, Cu and Al targets is found to overestimates our values for thin carbon foils significantly. Another model calculation is found to reproduce our b-values very well.

  20. 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.

  1. Ultra high vacuum system of the 3 MeV electron beam accelerator

    International Nuclear Information System (INIS)

    Puthran, G.P.; Jayaprakash, D.; Mishra, R.L.; Ghodke, S.R.; Majumder, R.; Mittal, K.C.; Sethi, R.C.

    2003-01-01

    Full text: A 3 MeV electron beam accelerator is coming up at the electron beam centre, Kharghar, Navi Mumbai. A vacuum of the order of 1x10 -7 mbar is desired in the beam line of the accelerator. The UHV system is spread over a height of 6 meters. The total surface area exposed to vacuum is 65,000 cm 2 and the volume is 200 litres. Distributed pumping is planned, to avoid undesirable vacuum gradient between any two sections of the beam-line. The electron beam is scanned in an area of 6 cms x 100 cms and it comes out of the scan-horn through a titanium foil of 50 micron thick. Hence the vacuum system is designed in such a way that, in the event of foil rupture during beam extraction, the electron gun, accelerating column and the pumps can be protected from sudden air rush. The vacuum in the beam-line can also be maintained in this condition. After changing the foil, scan-horn area can be separately pumped to bring the vacuum level as desired and can be opened to the beam-line. The design, vacuum pumping scheme and the safety aspects are discussed in this paper

  2. Experience with the Alderson Rando phantom. [17-MeV electrons

    Energy Technology Data Exchange (ETDEWEB)

    Somerwil, A; Kleffens, H.J. Van [Rotterdams Radio Therapeutisch Instituut (Netherlands)

    1977-04-01

    The dose delivered to the spinal cord is of particular interest in electron beam therapy of medulloblastoma. Lithium fluoride thermoluminescent dosimetry has been used in an assessment of the dose distributions from a 17 MeV electron beam in an Alderson Rando Phantom (Alderson, S.W., Lanzl, L.H., Rollins, M., and Spira, J., 1962, American J. of Roentgenology, Radium Therapy and Nuclear Medicine, vol. 87, 185). Measurements were also made on three autopsy specimens immersed in water. There were substantial differences between the two sets of results. The density of the bony part of the phantom seemed to be markedly lower than that of the water; radiographs of various parts of the phantom confirmed that large areas of low density existed. The manufacturers have stated that in order to simulate true in vivo conditions, an artificial skeleton would have to be introduced into the tissue-like material of the phantom, and that the real skeletons now used appear to be unsuitable for electron beam dosimetry. It is therefore doubtful whether this electron beam dosimetry justifies the expense associated with the insertion of these unsatisfactory skeletons into the soft tissue-equivalent material.

  3. Effect of MeV Electron Radiation on Europa’s Surface Ice Analogs

    Science.gov (United States)

    Gudipati, Murthy; Henderson, Bryana; Bateman, Fred

    2017-10-01

    MeV electrons that impact Europa’s trailing hemisphere and cause both physical and chemical alteration of the surface and near-surface. The trailing hemisphere receives far lower fluxes above 25 MeV as compared with lower energy particles, but can cause significant chemical and physical modifications at these energies. With NASA's planned Europa Clipper mission and a Europa Lander Concept on the horizon, it is critical to understand and quantify the effect of Europa’s radiation environment on the surface and near surface.Electrons penetrate through ice by far the deepest at any given energy compared to protons and ions, making the role of electrons very important to understand. In addition, secondary radiation - Bremsstrahlung, in X-ray wavelengths - is generated during high-energy particle penetration through solids. Secondary X-rays are equally lethal to life and penetrate even deeper than electrons, making the cumulative effect of radiation on damaging organic matter on the near surface of Europa a complex process that could have effects several meters below Europa’s surface. Other physical properties such as coloration could be caused by radiation.In order to quantify this effect under realistic Europa trailing hemisphere conditions, we devised, built, tested, and obtained preliminary results using our ICE-HEART instrument prototype totally funded by JPL’s internal competition funding for Research and Technology Development. Our Ice Chamber for Europa High-Energy Electron And Radiation-Environment Testing (ICE-HEART) operates at ~100 K. We have also implemented a magnet that is used to remove primary electrons subsequent to passing through an ice column, in order to determine the flux of secondary X-radiation and its penetration through ice.Some of the first results from these studies will be presented and their relevance to understand physical and chemical properties of Europa’s trailing hemisphere surface.This work has been carried out at Jet

  4. Observation of optical Smith-Purcell radiation at an electron beam energy of 855 MeV

    International Nuclear Information System (INIS)

    Kube, G.; Backe, H.; Euteneuer, H.; Grendel, A.; Hagenbuck, F.; Hartmann, H.; Kaiser, K.H.; Lauth, W.; Schoepe, H.; Wagner, G.; Walcher, Th.; Kretzschmar, M.

    2002-01-01

    Smith-Purcell radiation, generated when a beam of charged particles passes close to the surface of a diffraction grating, has been studied in the visible spectral range at wavelengths of 360 and 546 nm with the low emittance 855 MeV electron beam of the Mainz Microtron MAMI. The beam focused to a spot size of 4 μm (full width at half maximum) passed over optical diffraction gratings of echelle profiles with blaze angles of 0.8 deg., 17.27 deg., and 41.12 deg. and grating periods of 0.833 and 9.09 μm. Taking advantage of the specific emission characteristics of Smith-Purcell radiation a clear separation from background components, such as diffracted synchrotron radiation from upstream beam optical elements and transition radiation, was possible. The intensity scales with a modified Bessel function of the first kind as a function of the distance between electron beam and grating surface. Experimental radiation factors have been determined and compared with calculations on the basis of Van den Berg's theory [P.M. Van den Berg, J. Opt. Soc. Am. 63, 689 (1973)]. Fair agreement has been found for gratings with large blaze angles while the measurement with the shallow grating (blaze angle 0.8 deg.) is at variance with this theory. Finally, the optimal operational parameters of a Smith-Purcell radiation source in view of already existing powerful undulator sources are discussed

  5. 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.

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

    International Nuclear Information System (INIS)

    Lu Xianhai; Du Yingchao; Huang Wenhui; Tang Chuanxiang

    2014-01-01

    transverse 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. (authors)

  7. Confirm calculation of 12 MeV non-destructive testing electron linear accelerator target

    International Nuclear Information System (INIS)

    Ma Shudong; Zhang Rutong; Guo Yanbin; Zhou Yuan; Li Xuexian; Chen Yan

    2012-01-01

    The confirm calculation of 12 MeV non-destructive testing (NDT) electron linear accelerator (LINAC) target was studied. Firstly, the most optimal target thickness and related photon dose yield, distributions of dose rate, and related photon conversion efficiencies were got by calculation with specific analysis of the physical mechanism of the interactions between the beam and target; Secondly, the photon dose rate distribution, converter efficiencies, and thickness of various kinds of targets, such as W, Au, Ta, etc. were verified by MCNP simulation and the most optimal target was got using the MCNP code; Lastly, the calculation results of theory and MCNP were compared to confirm the validity of target calculation. (authors)

  8. Obwervation of 10 μm Smith-Purcell radiation from 45 MeV electrons

    International Nuclear Information System (INIS)

    Fernow, R.C.; Robertson, S.H.; Brownell, J.H.; Walsh, J.E.

    1997-01-01

    Using the high-brightness, high-energy electron beam at the Brookhaven Accelerator Test Facility we observe forward directed Smith-Purcell radiation in the mid-infrared spectral regime. This radiation can prove useful as a source of infrared radiation for other scientific studies as well as a providing a precursor investigation of the inverse process, namely the acceleration of electrons by means of the coupling of laser light with electrons via micro-structures

  9. Conceptual Design of a 14-MeV D-T Neutron Source for Material Inspection

    International Nuclear Information System (INIS)

    Kim, Jin-Choon; Oh, Byung-Hoon

    2007-01-01

    There is a worldwide need for the efficient inspection of cargo containers at airports, seaports and border crossings. And there is also a growing need for nondestructive inspection of metal objects such as airplane parts. The limitations of X-ray systems for the detection of explosives, drugs, and thick metal structures have stimulated interest in neutron radiograph or tomography. The weak link in such applications is the neutron source. The ideal neutron source should provide a high intensity, high-energy for sufficient penetration and activation, a reliable long-term operation, and a monoenergetic neutron beam. In this paper, we describe a conceptual design of a DT fusion neutron source (monoenergetic 14 MeV neutron generator) which satisfies the fore-mentioned requirements. The current design is based upon the actually proven system using the drive-in target principle. The design is versatile enough to accommodate various applications, ranging from material inspection and explosive interrogation to medical probing and cancer treatment

  10. 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. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

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

    International Nuclear Information System (INIS)

    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. (authors)

  12. Secondary gamma-ray skyshine from 14 MeV Neutron Source Facility (OKTAVIAN). Comparison of measurement with its simulation

    Energy Technology Data Exchange (ETDEWEB)

    Morotomi, Ryutaro; Kondo, Tetsuo; Murata, Isao; Yoshida, Shigeo; Takahashi, Akito [Osaka Univ., Department of Nuclear Engineering, Suita, Osaka (Japan); Yamamoto, Takayoshi [Osaka Univ., Radio Isotope Research Center, Suita, Osaka (Japan)

    2000-03-01

    Measurement of secondary gamma-ray skyshine was performed at the Intense 14 MeV Neutron Source Facility (OKTAVIAN) of Osaka University with NaI and Hp-Ge detectors. From the result of measurements, some mechanism of secondary gamma-ray skyshine from 14 MeV neutron source facility was found out. The analysis of the measured result were carried out with MCNP-4B for four nuclear data files of JENDL-3.2, JENDL-F.F., FENDL-2, and ENDF/B-VI. It was confirmed that all the nuclear data are fairly reliable for calculations of secondary gamma-ray skyshine. (author)

  13. High current polarized electron source

    Science.gov (United States)

    Suleiman, R.; Adderley, P.; Grames, J.; Hansknecht, J.; Poelker, M.; Stutzman, M.

    2018-05-01

    Jefferson Lab operates two DC high voltage GaAs photoguns with compact inverted insulators. One photogun provides the polarized electron beam at the Continuous Electron Beam Accelerator Facility (CEBAF) up to 200 µA. The other gun is used for high average current photocathode lifetime studies at a dedicated test facility up to 4 mA of polarized beam and 10 mA of un-polarized beam. GaAs-based photoguns used at accelerators with extensive user programs must exhibit long photocathode operating lifetime. Achieving this goal represents a significant challenge for proposed facilities that must operate in excess of tens of mA of polarized average current. This contribution describes techniques to maintain good vacuum while delivering high beam currents, and techniques that minimize damage due to ion bombardment, the dominant mechanism that reduces photocathode yield. Advantages of higher DC voltage include reduced space-charge emittance growth and the potential for better photocathode lifetime. Highlights of R&D to improve the performance of polarized electron sources and prolong the lifetime of strained-superlattice GaAs are presented.

  14. High efficiency charge recuperation for electron beams of MeV energies

    International Nuclear Information System (INIS)

    MacLachlan, J.A.

    1996-05-01

    Electron cooling of ion beams with energies of some GeV per nucleon requires high-quality electron beams of MeV energies and currents as high as several amperes. The enormous beam power dictates that the beam current be returned to the high voltage terminal which provides the accelerating potential. The beam is returned to a carefully designed collector within the terminal and biased a few kV positive with respect to it. Thus the load on the HV supply is only the accelerating potential times the sum of the beam current loss and the current used to maintain a graded potential on the accelerating structure. If one employs an electrostatic HV supply like a Van de Graaff with maximum charging current of a few hundred microA, the permissible fractional loss is ∼ 10 -4 . During the 15 years or so the concept of medium energy electron cooling has been evolving, the need to demonstrate the practicability of such high efficiency beam recovery has been recognized. This paper will review some experimental tests and further experiments which have been proposed. The design and status are presented for a new re-circulation experiment at 2 MV being carried out by Fermilab at National Electrostatics Corp

  15. The low energy (140 MeV) chemistry facility at the 500 MeV electron accelerator MEA at Amsterdam

    International Nuclear Information System (INIS)

    Brinkman, G.A.; Kapteyn, J.C.; Louwrier, P.W.F.; Lindner, L.; Peelen, B.; Polak, P.; Schimmel, A.; Stock, F.R.; Veenboer, J.T.; Visser, J.

    1980-01-01

    The facility includes the Low Energy Chemistry (LECH) hall equipped with a beam-line for pulse-radiolysis and a second one for the production of radioisotopes and for experiments with electron-free photon beams. It also includes the Low Energy Laboratory (LELAB) containing two chemistry laboratories and a control room. These facilities are also available to outside research groups. (orig./HP)

  16. Angular distributions for the charged components in a cascade shower induced by 350 MeV electrons

    International Nuclear Information System (INIS)

    Kobayashi, S.; Itoh, H.; Murakami, A.; Muto, T.

    1978-01-01

    The angular distributions of secondary electrons contained in a cascade shower are studied by using a streamer chamber. The primary electrons with energy of about 350 MeV are incident on a lead converter of various thickness. The angular data are analyzed for the number of electrons in a shower, and for the converter thickness. The obtained distributions show a systematic agreement with the Monte Carlo calculations presented by Messel and Crawford. (Auth.)

  17. Reactor physics experiments in PURNIMA sub critical facility coupled with 14 MeV neutron source

    International Nuclear Information System (INIS)

    Kumar, Rajeev; Degweker, S.B.; Patel, Tarun; Bishnoi, Saroj; Adhikari, P.S.

    2011-01-01

    developed at BARC. Hence it is important to experimentally study the statistical properties of the neutron source for noise experiments. To characterize the statistical properties of the 14 MeV neutron source, neutron counts were collected from DD as well as DT reaction using a time stamping data acquisition card. Data were analyzed to obtain the v/m, auto correlation function and power spectral density (PSD). The study indicates that the source is different from a purely Poisson source. (author)

  18. 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...... the average and the surface dose and to prove the applicability of the new low energy calorimeter for calibration purposes at 1.5 and 2 MeV electron energy. Alanine dosimeters of 2 mm thickness were used to calibrate the calorimeters and their use for nominal dose measurements was demonstrated in a series...... of intercomparisons. The use as routine dosimeters at electron accelerators operating in the energy range of 1.5-4 MeV was also demonstrated. (C) 2002 Elsevier Science Ltd. All rights reserved....

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

    CERN Multimedia

    Service Photo; CERN PhotoLab

    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.

  20. Slow positron beam production by a 14 MeV C.W. electron accelerator

    Science.gov (United States)

    Begemann, M.; Gräff, G.; Herminghaus, H.; Kalinowsky, H.; Ley, R.

    1982-10-01

    A 14 MeV c.w. electron accelerator is used for pair production in a tungsten target of 0.7 radiation lengths thickness. A small fraction of the positrons is thermalized and diffuses out of the surface ofsurface of a well annealed tungsten foil coated with MgO which is positioned immediately behind the target. The slow positrons are extracted from the target region and magnetically guided over a distance of 10 m onto a channelplate multiplier at the end of an S-shaped solenoid. The positrons are identified by their annihilation radiation using two NaI-detectors. The intensity of the slow positrons is proportional to the accelerator electron beam current. The maximum intensity of 2.2 × 10 5 slow positrons per second reaching thedetector at an accelerator current of 15 μA was limited by the power deposited in the uncooled target. The energy of the positrons is concentrated in a small region at about 1 eV and clearly demonstrates the emission of thermal positrons.

  1. Slow positron beam production by a 14 MeV c.w. electron accelerator

    International Nuclear Information System (INIS)

    Begemann, M.; Graeff, G.; Herminghaus, H.; Kalinowsky, H.; Ley, R.

    1982-01-01

    A 14 MeV c.w. electron accelerator is used for pair production in a tungsten target of 0.7 radiation lengths thickness. A small fraction of the positrons is thermalized and diffuses out of the surface of a well annealed tungsten foil coated with MgO which is positioned immediately behind the target. The slow positrons are extracted from the target region and magnetically guided over a distance of 10 m onto a channelplate multiplier at the end of an S-shaped solenoid. The positrons are identified by their annihilation radiation using two Nal-detectors. The intensity of the slow positrons is proportional to the accelerator electron beam current. The maximum intensity of 2.2 x 10 5 slow positrons per second reaching the detector at an accelerator current of 15 μA was limited by the power deposited in the uncooled target. The energy of the positrons is concentrated in a small region at about 1 eV and clearly demonstrates the emission of thermal positrons. (orig.)

  2. Physics design of a 10 MeV, 6 kW travelling wave electron linac for ...

    Indian Academy of Sciences (India)

    2016-10-11

    Oct 11, 2016 ... We present the physics design of a 10 MeV, 6 kW S-band (2856 MHz) electron linear ... linac (in contrast with standing wave linac) is that it accepts the RF power over a band of frequencies. Three- ... structures are preferred for relatively higher energy ... klystron in a TW linac, which results in cost reduction.

  3. A 100 MeV linac for the SR light source

    International Nuclear Information System (INIS)

    Iwata, H.; Takahashi, T.; Kaneko, N.; Nakashizu, T.; Hara, O.

    1992-01-01

    A 4 m long linear accelerator has been designed to operate with the energy gain of 100 MeV and a beam current of 100 mA. It is scheduled to be installed into the compact synchrotron radiation light source (LUNA) in near future. In this report, several pre-tests and the design of this linac are discussed. High power testing by a 0.5 m long test linac shows that it takes 110 hr aging to reach no arcing condition at an electric field strength of 25 MeV/m. Another diffusion bonding test shows that it is possible to make the deformation less than 5μm per cell under optimum conditions of temperature and pressure. This linac is composed of 5 units, made by diffusion bonding. Each unit is bolted together to form a 4 m long linear accelerator. The entire assembly is placed within a cylinder which serves both as a vacuum envelope and as the support structure. (Author) 5 figs., 2 tabs

  4. Monte-Carlo calculations of forward directed bremsstrahlung produced by 20 and 45 MeV electrons on tungsten

    International Nuclear Information System (INIS)

    Goosman, D.R.

    1983-01-01

    The SANDYL Monte-Carlo code has been used to calculate the Bremsstrahlung photon production from beams of parallel electrons incident upon three target geometries. These are 20 MeV electrons onto 1 mm of tungsten + 59 mm of Be, which simulates the operating parameters of the FXR electron accelerator at LLNL Bldg. 801, 45 MeV electrons onto 1 mm of tungsten, and finally 45 MeV electrons onto 1 mm of tungsten and 147 mm of Be. The latter two situations simulate possible future modifications to the FXR accelerator. Graphs of the spectral shape of the Bremsstrahlung photons emitted with angles between 0 0 and 1 0 to the electron direction, the angular distribution of photon-MeV, and the dose reduction curves for each of the three geometries are given. The latter dose reduction curves allow one to calculate forward-directed photon fluxes in real-life situations where the electron beam has non-zero angular divergence

  5. Application of clear polymethylmethacrylate dosimeter Radix W to a few MeV electron in radiation processing

    International Nuclear Information System (INIS)

    Seito, Hajime; Ichikawa, Tatsuya; Hanaya, Hiroaki; Sato, Yoshishige; Kaneko, Hirohisa; Haruyama, Yasuyuki; Watanabe, Hiroshi; Kojima, Takuji

    2009-01-01

    Characteristics of clear PMMA dosimeter (Radix W) were studied for electron irradiation and compared with the response for gamma irradiation. The dose-response curves were nearly linear up to 30 kGy and become sublinear at higher doses. The radiation-induced absorbance was reduced with 6% within 4 h after irradiation. Dose comparisons were performed for 2, 3, 4 and 5 MeV electron irradiation using cellulose triacetate dosimeter (CTA) (FTR-125) and Radix W dosimeters which were independently calibrated for 2 MeV electrons and 60 Co gamma-rays using calorimeter and ionizing chamber, respectively. The doses estimated by CTA and Radix W were different by about 20%. The magnitude of this difference was, however, independent of electron energy.

  6. Effect of 1MeV electron beam on transistors and circuits

    International Nuclear Information System (INIS)

    Lee, Tae Hoon

    1998-02-01

    It has been known that semiconductor devices operating in a radiation environment exhibited significant alterations of their electrical responses. Since an electron beam bombardment produces lattice damage in Si and charged defects in SiO 2 , several electrical parameters of transistors exhibit significant changes. Those parameters are the current gain of BJT (Bipolar Junction Transistor) and the threshold voltage of MOSFET (Metal Oxide Semiconductor Field Effect Transistor). The degradation of transistors brings about that of circuits. This paper presents the results of experiments and simulations performed to study the effects of 1MeV electron beam irradiation on selected silicon transistors and circuits. For BJTs, the current gains of npn (2N3904) and pnp (2N3906) linearly decreased as the irradiation dose increased, and from this result, the damage constants, Ks were obtained as 13.65 for 2N3904 and 22.52 for 2N3906 in MGy, indicating a more stable operation in the electron radiation environment for pnp than that for npn. The decrease of current gain was due to that of minority-carrier lifetime in the base region. For MOSFETs (CD4007s), the threshold voltages of NMOS and PMOS shifted to the lower values, which was resulted from the accumulation of charge in SiO 2 . The charges could be categorized into fixed oxide charge and interfacial trap charge. From experimental results, the amounts of the induced charges could be quantitatively estimated. These degradations of transistors brought about the decrease in the voltage gain of CE (Common Emitter) amplifier and the shifts in the inverting voltage of inverter. Additionally, PSpice simulations of these circuits were carried out by modeling of irradiated transistors. The comparison of simulation with experiment showed the relatively good agreement of simulation for the degradation of circuits after irradiation

  7. Dose Mapping of Frozen Chickens Using 10 MeV Electrons

    International Nuclear Information System (INIS)

    Eichenberger, C.; Haider, S.A.; Maxim, J.; Miller, R.B.

    2005-09-01

    Irradiation of locally produced and imported food products was approved in the Kingdom of Saudi Arabia (KSA) in 2002. SureBeam Middle East (SME) has constructed the first food irradiation facility in Riyadh, KSA and will begin production irradiation in Q4 of 2005. In an effort to find efficient and cost effective means of irradiating frozen whole body chickens, SME has sponsored dose mapping studies using a 10 MeV dual electron beam processing system at the Electron Beam Food Research Facility at Texas A and M University (TAMU). Frozen chickens available to consumers in KSA range in size from nominal 600 grams to 1400 grams. Poultry processors typically provide retailers with equal weight birds packaged ten to a box (2 rows of 5 birds). Areal densities of the packages increase with the weight of the birds. For this study equivalent size birds were grown and processed by the Department of Poultry Science at TAMU and packaged in the same manner as in KSA. The goal of this investigation was to determine which size birds could be processed at a minimum dose of 2.5 kGy and not have the maximum dose exceed the level where negative sensory effects become noticeable. The minimum dose was chosen to reduce the population of any salmonella contamination by more than a factor of 1000. A description of the experimental set up and results of the dose mapping of frozen whole body chickens are reported herein, as are the results which indicate that electron beam processing of frozen chickens up to approximately 1000 grams can be readily accomplished and that processing of chickens up to 1400 grams may be possible Salmonella

  8. Characterization of a power bipolar transistor as high-dose dosimeter for 1.9-2.2 MeV electron beams

    Energy Technology Data Exchange (ETDEWEB)

    Fuochi, P.G., E-mail: fuochi@isof.cnr.i [ISOF-CNR Institute, Via P. Gobetti 101, I-40129, Bologna (Italy); Lavalle, M.; Corda, U. [ISOF-CNR Institute, Via P. Gobetti 101, I-40129, Bologna (Italy); Kuntz, F.; Plumeri, S. [Aerial, Parc d' Innovation Rue Laurent Fries F-67400 Illkirch (France); Gombia, E. [IMEM-CNR Institute, Viale delle Scienze 37 A, Loc. Fontanini, 43010 Parma (Italy)

    2010-04-15

    Results of the characterization studies on a power bipolar transistor investigated as a possible radiation dosimeter under laboratory condition using electron beams of energies from 2.2 to 8.6 MeV and gamma rays from a {sup 60}Co source and tested in industrial irradiation plants having high-activity {sup 60}Co gamma-source and high-energy, high-power electron beam have previously been reported. The present paper describes recent studies performed on this type of bipolar transistor irradiated with 1.9 and 2.2 MeV electron beams in the dose range 5-50 kGy. Dose response, post-irradiation heat treatment and stability, effects of temperature during irradiation in the range from -104 to +22 deg. C, dependence on temperature during reading in the range 20-50 deg. C, and the difference in response of the transistors irradiated from the plastic side and the copper side are reported. DLTS measurements performed on the irradiated devices to identify the recombination centres introduced by radiation and their dependence on dose and energy of the electron beam are also reported.

  9. Measurement of angular distribution of neutron flux for the 6 MeV race-track microtron based pulsed neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Patil, B.J., E-mail: bjp@physics.unipune.ernet.i [Department of Physics, University of Pune, Pune 411 007 (India); Chavan, S.T.; Pethe, S.N.; Krishnan, R. [SAMEER, IIT Powai Campus, Mumbai 400 076 (India); Dhole, S.D., E-mail: sanjay@physics.unipune.ernet.i [Department of Physics, University of Pune, Pune 411 007 (India)

    2010-09-15

    The 6 MeV race track microtron based pulsed neutron source has been designed specifically for the elemental analysis of short lived activation products, where the low neutron flux requirement is desirable. Electrons impinges on a e-{gamma} target to generate bremsstrahlung radiations, which further produces neutrons by photonuclear reaction in {gamma}-n target. The optimisation of these targets along with their spectra were estimated using FLUKA code. The measurement of neutron flux was carried out by activation of vanadium at different scattering angles. Angular distribution of neutron flux indicates that the flux decreases with increase in the angle and are in good agreement with the FLUKA simulation.

  10. Confinement of 2,4 MeV deuterons by plasmoids and focalization of electron beams in plasma focus discharges

    International Nuclear Information System (INIS)

    Nardi, V.; Bostick, W.; Prior, W.; Feugeas, J.; Bortolotti, A.

    1982-01-01

    A detailed analysis has been completed on the internal structure of ions and electron beams which are efected, along the system axis, in opposite directions (0 0 and 180 0 ). An image (contact print) of plasmoids which emit MeV deuterons is formed by the deuteron emission and it is revealed by etching deuteron tracks in a target of plastic material (CR-39). Ion-imaging with different energy filters discriminates between tracks of plasmoid ions and tracks of charged products of D-D fusion reactions. Ions-imaging can also discriminate plasmoid deuterons from MeV deuterons of a directed beam. (L.C.) [pt

  11. Moderate pressure plasma source of nonthermal electrons

    Science.gov (United States)

    Gershman, S.; Raitses, Y.

    2018-06-01

    Plasma sources of electrons offer control of gas and surface chemistry without the need for complex vacuum systems. The plasma electron source presented here is based on a cold cathode glow discharge (GD) operating in a dc steady state mode in a moderate pressure range of 2–10 torr. Ion-induced secondary electron emission is the source of electrons accelerated to high energies in the cathode sheath potential. The source geometry is a key to the availability and the extraction of the nonthermal portion of the electron population. The source consists of a flat and a cylindrical electrode, 1 mm apart. Our estimates show that the length of the cathode sheath in the plasma source is commensurate (~0.5–1 mm) with the inter-electrode distance so the GD operates in an obstructed regime without a positive column. Estimations of the electron energy relaxation confirm the non-local nature of this GD, hence the nonthermal portion of the electron population is available for extraction outside of the source. The use of a cylindrical anode presents a simple and promising method of extracting the high energy portion of the electron population. Langmuir probe measurements and optical emission spectroscopy confirm the presence of electrons with energies ~15 eV outside of the source. These electrons become available for surface modification and radical production outside of the source. The extraction of the electrons of specific energies by varying the anode geometry opens exciting opportunities for future exploration.

  12. Mechanical properties of organic composite materials irradiated with 2 MeV electrons

    International Nuclear Information System (INIS)

    Egusa, S.; Kirk, M.A.; Birtcher, R.C.; Argonne National Lab., IL; Hagiwara, M.; Kawanishi, S.

    1983-01-01

    Four kinds of cloth-filled organic composites (filter: glass or carbon fiber; matrix; epoxy or polyimide resin) were irradiated with 2 MeV electrons at room temperature, and were examined with regard to the mechanical properties. Following irradiation the Young's (tensile) modulus of these composites remains practically unchanged even after irradiation up to 15.000 Mrad. The shear modulus and the ultimate strength, on the other hand, begin to decrease after the absorbed dose reaches about 2.000 Mrad for the glass/epoxy composite and about 5.000-10.000 Mrad for the other composites. This result is ascribed to the decrease in the capacity of load transfer from the matrix to the fiber due to the radiation damage at the interface, and the dose dependence is interpreted and formulated based on the mechanics of composite materials and the target theory used in radiation biology. As to the fracture behavior, the propagation energy increases from the beginning of irradiation. This result is attributed to the radiation-induced decrease in the bonding energy at the interface. (orig.)

  13. 1-MeV electron beam propagation experiments in neutral gas

    International Nuclear Information System (INIS)

    Greenspan, M.A.; Rose, E.A.

    1984-01-01

    Experiments were performed studying the propagation of a 1-MeV, 10-ns electron beam at currents of 2-8 kA. Propagation was studied in a 7.6-cm-diam glass guide tube, the same tube with a conducting screen inside, and in a 3.4-m-diam chamber. In the guide tube with the screen, ion-focused propagation is observed at low pressures (≤ 40 Pa) with net current equal to beam current. At higher pressures (55-130 Pa), a notch in beam current is observed for pressure time products of ≅ 100 Pa-ns. Between 270 Pa and 1070 Pa, good propagation is again observed with net currents of 50-70% of the beam current. The net current fraction of beam current increases with increasing pressure and with decreasing beam current. At pressure above 1070 Pa, hose instability occurs, and net current nearly equal to beam current is observed. The hose frequency is in reasonable accord with theory. Nose erosion is minimized at pressures for 1000-2000 Pa depending on beam current, and increases at lower and higher pressures

  14. Application of the Ethanol-Chlorobenzene Dosimeter to Electron Beam Dosimetry: Pulsed 10 MeV Electrons

    Energy Technology Data Exchange (ETDEWEB)

    Dvornik, I.; Razem, D.; Baric, M. [Institute ' ' Ruder Boskovic' ' , Zagreb, Yugoslavia (Croatia)

    1969-12-15

    With gamma irradiation, the ethanol-chlorobenzene chemical dosimetric systems have shown valuable properties. They are simple to prepare and analyse, the G(HC1) values are not sensitive to normal impurities and are constant within the dose range of interest for processing. This paper describes the experiments performed with 10 MeV pulsed electrons from the linear accelerator of the Research Establishment Riso, Denmark (7 microsecond pulses repeated 300 times per second, 10{sup 9} rad/sec in the pulse). The irradiations were calibrated calorimetrically. The G(HC1) values independent of dose up to 40 Mrad are given as a function of chlorobenzene concentration. The comparison with gamma irradiations shows only insignificant differences in the G-values. Above 10 vol. % chlorobenzene the G-values are approximately constant up to 20 Mrad or more, and are to within 2% equal to those obtained for gamma rays with free access of air. The addition of 0.04% of acetone or benzene to the systems had within the experimental error, no influence upon the G(HC1). The results show the applicability of ethanol-chlorobenzene dosimeters to the dosimetry of electron beam irradiations at dose rates as high as 10{sup 9} rad/sec and dosages up to 6 Mrad. (author)

  15. Source of spin polarized electrons

    International Nuclear Information System (INIS)

    Pierce, D.T.; Meier, F.A.; Siegmann, H.C.

    1976-01-01

    A method is described of producing intense beams of polarized free electrons in which a semiconductor with a spin orbit split valence band and negative electron affinity is used as a photocathode and irradiated with circularly polarized light

  16. Development of the integrated control system for the microwave ion source of the PEFP 100-MeV proton accelerator

    Science.gov (United States)

    Song, Young-Gi; Seol, Kyung-Tae; Jang, Ji-Ho; Kwon, Hyeok-Jung; Cho, Yong-Sub

    2012-07-01

    The Proton Engineering Frontier Project (PEFP) 20-MeV proton linear accelerator is currently operating at the Korea Atomic Energy Research Institute (KAERI). The ion source of the 100-MeV proton linac needs at least a 100-hour operation time. To meet the goal, we have developed a microwave ion source that uses no filament. For the ion source, a remote control system has been developed by using experimental physics and the industrial control system (EPICS) software framework. The control system consists of a versa module europa (VME) and EPICS-based embedded applications running on a VxWorks real-time operating system. The main purpose of the control system is to control and monitor the operational variables of the components remotely and to protect operators from radiation exposure and the components from critical problems during beam extraction. We successfully performed the operation test of the control system to confirm the degree of safety during the hardware performance.

  17. 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

  18. Secondary electron ion source neutron generator

    Science.gov (United States)

    Brainard, John P.; McCollister, Daryl R.

    1998-01-01

    A neutron generator employing an electron emitter, an ion source bombarded by the electrons from the electron emitter, a plasma containment zone, and a target situated between the plasma containment zone and the electron emitter. The target contains occluded deuterium, tritium, or a mixture thereof

  19. Design and performance of the 40 MeV linac and beam transport system for the 1 GeV synchrotron radiation source at SORTEC

    International Nuclear Information System (INIS)

    Shiota, M.; Hiraki, A.; Mizota, M.; Iida, T.; Haraguchi, M.; Kuno, K.; Nakamura, S.; Ohno, M.; Tomimasu, T.

    1990-01-01

    A 1 Gev synchrotron radiation source (SOR) system has been installed and is now being adjusted at SORTEC corporation. This paper reports the configuration and the beam test results of the 40 MeV electron linac (pre-injector) and the beam transport line to the electron synchrotron used in this system. The output beam from the linac must be low emittance, small energy spread, and stable in energy. The beam transport line must also efficiently lead the beam from the linac to the electron synchrotron. This linac produced the beam current of 130 mA, with an energy spread of 1.3 % (FWHM), and an emittance of 0.7 πmm·mrad. The beam characteristics were verified by various beam monitors on the beam transport line. (author)

  20. High-resolution inelastic electron scattering on 208Pb at 50 and 63.5 MeV and fragmentation of the magnetic quadrupole strength

    International Nuclear Information System (INIS)

    Knuepfer, W.; Frey, R.; Richter, A.; Schwierczinski, A.; Spamer, E.; Titze, O.

    1977-12-01

    High-resolution inelastic electron scattering (FWHM approximately equal to 33 keV) with 50 MeV and 63.5 MeV electrons on 208 Pb has been used to study magnetic excitations between Esub(x) = 6 MeV and 8 MeV. Angular distributions were analyzed in terms of the DWBA with RPA wave functions. Eight Isup(π) = 2- states carrying a total strength ΣB(M2) = 8500 μ 2 sub(K) fm 2 have been found. The strong fragmentation is in qualitative agreement with theoretical predictions. (orig.) [de

  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. The study of 1 MeV electron irradiation induced defects in N-type and P-type monocrystalline silicon

    Science.gov (United States)

    Babaee, S.; Ghozati, S. B.

    2017-12-01

    Despite extensive use of GaAs cells in space, silicon cells are still being used. The reason is that not only they provide a good compromise between efficiency and cost, but also some countries do not have the required technology for manufacturing GaAs. Behavior of a silicon cell under any levels of charged particle irradiation could be deducted from the results of a damage equivalent 1 MeV electron irradiation using the NASA EQflux open source software package. In this paper for the first time, we have studied the behavior of a silicon cell before and after 1 MeV electron irradiation with 1014, 1015 and 1016 electrons-cm-2 fluences, using SILVACO TCAD simulation software package. Simulation was carried out at room temperature under AM0 condition. Results reveal that open circuit voltage and efficiency decrease after irradiation while short circuit current shows a slight increase in the trend around 5 × 1016 electrons-cm-2, and short circuit current loss plays an important role on efficiency changes rather than open circuit voltage.

  3. 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.

  4. Calculation of energy and angular distributions of the bremsstrahlung of 10 MeV electrons bombarding a thick tungsten target

    International Nuclear Information System (INIS)

    Tsovbun, V.I.

    1977-01-01

    Computer calculations have been performed to extend the data available on energy and angular distribution of the 10 MeV electron bremsrahlung into a higher angle region. The ETRAN-16D program developed by R.G.Berger for calculation of electron-photon cascades passing through matter using computers IBM-360 and UNIVAC-1108 was modified to operate with the CDC-6500 computer. A brief summary of the program is provided. An angular distribution of the bremsstrahlung dose absorbed in the air has been also calculated. The results extended into the 90-180 deg region can be used to calculate the biological shield of electron accelerators

  5. Scattering of 14. 0 MeV electrons. Fundamental study of the scattering foil. [Angular distribution, 14. 0 MeV, gaussian distribution

    Energy Technology Data Exchange (ETDEWEB)

    Takei, C [Kyushu Univ., Fukuoka (Japan). School of Health Sciences; Yoshimoto, S

    1977-07-01

    The angular distribution of 14.0 MeV electrons scattered by thin Al and Pb foils has been measured, since the beam flatness is important on the high energy electron therapy. These distributions measured were almost completely Gaussian. The root mean square scattering angles were obtained and were compared with the theories of Williams and Rossi. In our experiments the root mean square scattering angles obtained have the experimental errors of about 4% and 1% for 5/sup 0/ and 10/sup 0/, respectively. For Al foils of 0.5 mm to 3.0 mm the experimental values of the root mean square scattering angles are 5.49/sup 0/ and 12.43/sup 0/ and are 30% to 10% higher than those predicted by Williams. Although, these values are 4% to 9% lower than those calculated from the theory of Rossi. The root mean square scattering angles obtained with Pb foils of 0.1 mm to 0.3 mm are 9.62/sup 0/ to 18.05/sup 0/ and are 14% to 18% higher than Williams, and are 14% to 7% lower than those theoretically calculated by Rossi.

  6. Source of monoenergetic electrons for beta dosimetry

    International Nuclear Information System (INIS)

    Graham, C.L.; Elliott, J.H.

    1983-01-01

    We have developed an electron spectrometer which can produce a continuous beam of monoenergetic electrons. The spectrometer uses 20 millicuries of Cs-137 as a source of electrons which can be magnetically focused at the exit port. Various electron energies can be selected by changing the magnetic field. The maximum electron energy and dose rate for the present design are approximately 630 keV and 1.5 rads per hour, respectively

  7. Deeply inelastic collisions as a source of intermediate mass fragments at E/A = 27 MeV

    International Nuclear Information System (INIS)

    Borderie, B.; Montoya, M.; Rivet, M.F.; Jouan, D.; Cabot, C.; Fuchs, H.; Gardes, D.; Gauvin, H.; Jacquet, D.; Monnet, F.

    1988-01-01

    Intermediate-mass fragments detected in coincidence with heavy residues were measured in 40 Ar induced reactions on Ag at E/A = 27 MeV. From the observed characteristics, it is inferred that intermediate-mass fragments associated with the so-called intermediate-velocity source come mainly from deeply inelastic collisions occurring after or at the same time as preequilibrium particle emission. (orig.)

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

    International Nuclear Information System (INIS)

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

    2006-01-01

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

  9. Performance of the 100 MeV injector linac for the electron storage ring at Kyoto University

    International Nuclear Information System (INIS)

    Shirai, T.; Sugimura, T.; Iwashita, Y.; Kakigi, S.; Fujita, H.; Tonguu, H.; Noda, A.; Inoue, M.

    1996-01-01

    An electron linear accelerator has been constructed as an injector of a 300 MeV electron storage ring (Kaken Storage Ring, KSR) at Institute for Chemical Research, Kyoto University. The output beam energy of the linac is 100 MeV and the designed beam current is 100 mA at the 1 μsec long pulse mode. The transverse and longitudinal emittance are measured to evaluate the beam quality for the beam injection into the KSR. They are observed by the profile monitors combined with quadrupole magnets or an RF accelerator. The results are that the normalized transverse emittance is 120 π.mm.mrad. The longitudinal emittance is 15 π.deg.MeV and the energy spread is ±2.2 %. (author)

  10. Electromagnetic design and beam dynamics studies for a 10 MeV, 10 kW electron linac

    International Nuclear Information System (INIS)

    Dhingra, Rinky; Kulkarni, Nita S.; Kumar, Vinit

    2013-01-01

    Bi-periodic on-axis coupled standing wave linac is seen as an attractive choice for low energy (∼10 MeV) electron accelerators for industrial applications. In this paper, we present the physics design of an S-band bi-periodic on-axis coupled standing wave structure operating in π/2 mode. The structure operates at 2856 MHz and can accelerate electrons to 10 MeV. The 2D optimization of structure cells carried out using SUPERFISH is reported. Magnetic coupling is achieved through bean shaped coupling slots. Analytical calculations have been carried out to fix the dimensions of coupling slots. The paper discusses the complete 3D design of accelerating structure with coupling slots carried out using CST-MWS. The approach used to achieve confluence is outlined. Finally, the beam dynamics studies carried out using PARMELA are also discussed. (author)

  11. Thermoluminescent response of LiF: Mg, Cu, P (GR-200) below an electron beam of 6 MeV

    International Nuclear Information System (INIS)

    Torijano C, E.F.S.; Azorin N, J.; Villasenor N, I.; Lujan C, P.J.; Rivera M, T.

    2007-01-01

    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)

  12. Preliminary microstructural characterization by transmission electron microscopy of 14 MeV neutron irradiated type 316 stainless steel

    International Nuclear Information System (INIS)

    Echer, C.J.

    1977-01-01

    Substantial changes in the mechanical properties of 316 stainless steel were observed after neutron irradiation (phi/sub t/ = 2.3 x 10 21 n/m 2 and E = 14 MeV) at 25 0 C. Comparison of microstructures of the unirradiated and neutron irradiated materials were evaluated using transmission electron microscopy. Evidence of small defect clusters in the irradiated material was found. These findings are consistent with other investigators also evaluating low dose irradiations

  13. Microwave system of the 7-10 MeV electron linear accelerator ALIN for medical applications

    International Nuclear Information System (INIS)

    Martin, D.; Iliescu, E.; Stirbet, M.; Oproiu, C.; Vintan, I.

    1978-01-01

    A detailed description of the Central Institute of Physics 10 MeV linear microwave system and its associated subsystems are presented. Methods of impedance matching to obtain maximum power transfer are described along with broadband design methods for transmission-line impedance transformers. Experimental results for such microwave devices are included. With respect to microwave device performances, simultaneous high efficiency and high power capability with reliability and long life at relatively low unit cost have only recently been achieved as typical device characteristics. Industrial, medical and scientific application of microwave electron accelerators have markedly influenced microwave research progress. Radiographic linear accelerators have grown substantially mainly during the past few years. Following this, the improvements of microwave device performances solicit our attention. The first electron therapy Linear Accelerator ALIN 10 marks a new stage in the development of such instrumentation. Its subsequent ALIN 15 is designed to produce a maximum energy of 18 MeV to widen its applicability in radiotherapy. In addition, a new electron linear accelerator of 8 MeV for nondestructive testing has been started. (author)

  14. ECR ion source with electron gun

    Science.gov (United States)

    Xie, Zu Q.; Lyneis, Claude M.

    1993-01-01

    An Advanced Electron Cyclotron Resonance ion source (10) having an electron gun (52) for introducing electrons into the plasma chamber (18) of the ion source (10). The ion source (10) has a injection enclosure (12) and a plasma chamber tank (14). The plasma chamber (18) is defined by a plurality of longitudinal magnets (16). The electron gun (52) injects electrons axially into the plasma chamber (18) such that ionization within the plasma chamber (18) occurs in the presence of the additional electrons produced by the electron gun (52). The electron gun (52) has a cathode (116) for emitting electrons therefrom which is heated by current supplied from an AC power supply (96) while bias potential is provided by a bias power supply (118). A concentric inner conductor (60) and Outer conductor (62) carry heating current to a carbon chuck (104) and carbon pusher (114) Which hold the cathode (116) in place and also heat the cathode (16). In the Advanced Electron Cyclotron Resonance ion source (10), the electron gun (52) replaces the conventional first stage used in prior art electron cyclotron resonance ion generators.

  15. Coherent bremsstrahlung and channeling radiation from electrons of one to three MeV in silicon and gold

    International Nuclear Information System (INIS)

    Watson, J.E.

    1981-01-01

    The observation of sharp peaks in the x-ray spectrum from 1 to 3 MeV electrons striking thin single crystals of silicon and gold is reported. These peaks were observed in the range 1 to 25 keV. The peaks are of two different origins, both direct results of the periodic nature of the target crystals. The first kind of radiation is caused by the interference of incoming and scattered electron wave functions. Because of the periodicity of the target material there is a coherence effect for certain bremsstrahlung wave vectors. This coherent bremsstrahlung, though well known at very high electron energies, has never been adequately studied at electron energies below several hundred MeV. Detailed agreement between theoretical prediction and observation in silicon is shown. The second kind of radiation is caused by electrons channeled along major crystal axes. The electrons enter certain quantized orbits as they channel and may emit photons as a consequence of transitions between the various orbits. Observations of channeling radiation for various crystal axes in silicon are presented. Both phenomena were observed in gold, the first such observation for any metallic target

  16. Design and development of 3 MeV, 30 kW DC industrial electron accelerator at Electron Beam Centre, Kharghar

    International Nuclear Information System (INIS)

    Mittal, K.C.; Nanu, K.; Jain, A.

    2006-01-01

    High power electron beam accelerators are becoming an important tool for industrial radiation process applications. Keeping this in mind, a 3 MeV, 10 mA, 30 kW DC industrial electron accelerator has been designed and is in advanced stage of development at Electron Beam Center, Kharghar, Navi Mumbai. The operating range of this accelerator is 1 MeV to 3 MeV with maximum beam current of 10 mA. Electron beam at 5 keV is generated in electron gun with LaB 6 cathode and is injected into accelerating column at a vacuum of 10 -7 torr. After acceleration the beam is scanned and taken out in air through a 100 cm X 7 cm titanium window for radiation processing applications. The high voltage accelerating power supply is based on a capacitive coupled parallel fed voltage multiplier scheme operating at 120 kHz. A 50 kW oscillator feeds power to high voltage multiplier column. The electron gun, accelerating column and high voltage multiplier column are housed in accelerator tank filled with SF 6 gas insulation at 6 kg/cm 2 . The accelerator is located in a RCC building with product conveyor for handling products. A central computerized control system is adopted for operation of the accelerator. Accelerator is in the advance stage of commissioning. Many of the subsystems have been commissioned and tested. This paper describes the design details and current status of the accelerator and various subsystems. (author)

  17. Attenuation data of point isotropic neutron sources up to 400MeV in water, ordinary concrete and iron

    Energy Technology Data Exchange (ETDEWEB)

    Kotegawa, Hiroshi; Tanaka, Shun-ichi; Sakamoto, Yukio; Nakane, Yoshihiro; Nakashima, Hiroshi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1994-08-01

    A comprehensive attenuation data of dose equivalent for point isotropic monoenergetic neutron sources up to 400MeV in infinite shields of water, ordinary concrete and iron has been calculated using the ANISN-JR code and a neutron-photon multigroup macroscopic cross section HIL086R. The attenuation factors were fitted to a 4th order polynomial exponent formula, making possible to use easily for point kernel codes. Additional data in finite shielding geometry was also calculated to correct the effect due to infinite medium, giving the maximum correction of 0.23 in the region for more 400 cm distance from neutron source of 400 MeV in iron shield. Effective attenuation length for monoenergetic neutrons have been studied in detail. Subsequently, it was shown that the attenuation length was strongly dependent upon the penetration length and the Moyer`s formula using a single attenuation length brought large error into the dose estimation behind thick shields for the intermediate energy neutrons up to 400 MeV. Furthermore, it was demonstrated that there was difference more than 50 % in the attenuation length of iron between the calculations with HIL086R and HIL086 because of the self-shielding effect. (author).

  18. SU-F-T-71: A Practical Method for Evaluation of Electron Virtual Source Position

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Z; Jiang, W; Stuart, B; Leu, S; Feng, Y [East Carolina University, Greenville, North Carolina (United States); Liu, T [Houston Methodist Hospital, Sugar Land, TX (United States)

    2016-06-15

    Purpose: Since electrons are easily scattered, the virtual source position for electrons is expected to locate below the x-ray target of Medical Linacs. However, the effective SSD method yields the electron virtual position above the x-ray target for some applicators for some energy in Siemens Linacs. In this study, we propose to use IC Profiler (Sun Nuclear) for evaluating the electron virtual source position for the standard electron applicators for various electron energies. Methods: The profile measurements for various nominal source-to-detector distances (SDDs) of 100–115 cm were carried out for electron beam energies of 6–18 MeV. Two methods were used: one was to use a 0.125 cc ion chamber (PTW, Type 31010) with buildup mounted in a PTW water tank without water filled; and the other was to use IC Profiler with a buildup to achieve charge particle equilibrium. The full width at half-maximum (FWHM) method was used to determine the field sizes for the measured profiles. Backprojecting (by a straight line) the distance between the 50% points on the beam profiles for the various SDDs, yielded the virtual source position for each applicator. Results: The profiles were obtained and the field sizes were determined by FWHM. The virtual source positions were determined through backprojection of profiles for applicators (5, 10, 15, 20, 25). For instance, they were 96.415 cm (IC Profiler) vs 95.844 cm (scanning ion chamber) for 9 MeV electrons with 10×10 cm applicator and 97.160 cm vs 97.161 cm for 12 MeV electrons with 10×10 cm applicator. The differences in the virtual source positions between IC profiler and scanning ion chamber were within 1.5%. Conclusion: IC Profiler provides a practical method for determining the electron virtual source position and its results are consistent with those obtained by profiles of scanning ion chamber with buildup.

  19. SU-F-T-71: A Practical Method for Evaluation of Electron Virtual Source Position

    International Nuclear Information System (INIS)

    Huang, Z; Jiang, W; Stuart, B; Leu, S; Feng, Y; Liu, T

    2016-01-01

    Purpose: Since electrons are easily scattered, the virtual source position for electrons is expected to locate below the x-ray target of Medical Linacs. However, the effective SSD method yields the electron virtual position above the x-ray target for some applicators for some energy in Siemens Linacs. In this study, we propose to use IC Profiler (Sun Nuclear) for evaluating the electron virtual source position for the standard electron applicators for various electron energies. Methods: The profile measurements for various nominal source-to-detector distances (SDDs) of 100–115 cm were carried out for electron beam energies of 6–18 MeV. Two methods were used: one was to use a 0.125 cc ion chamber (PTW, Type 31010) with buildup mounted in a PTW water tank without water filled; and the other was to use IC Profiler with a buildup to achieve charge particle equilibrium. The full width at half-maximum (FWHM) method was used to determine the field sizes for the measured profiles. Backprojecting (by a straight line) the distance between the 50% points on the beam profiles for the various SDDs, yielded the virtual source position for each applicator. Results: The profiles were obtained and the field sizes were determined by FWHM. The virtual source positions were determined through backprojection of profiles for applicators (5, 10, 15, 20, 25). For instance, they were 96.415 cm (IC Profiler) vs 95.844 cm (scanning ion chamber) for 9 MeV electrons with 10×10 cm applicator and 97.160 cm vs 97.161 cm for 12 MeV electrons with 10×10 cm applicator. The differences in the virtual source positions between IC profiler and scanning ion chamber were within 1.5%. Conclusion: IC Profiler provides a practical method for determining the electron virtual source position and its results are consistent with those obtained by profiles of scanning ion chamber with buildup.

  20. MeV gamma-ray observation with a well-defined point spread function based on electron tracking

    Science.gov (United States)

    Takada, A.; Tanimori, T.; Kubo, H.; Mizumoto, T.; Mizumura, Y.; Komura, S.; Kishimoto, T.; Takemura, T.; Yoshikawa, K.; Nakamasu, Y.; Matsuoka, Y.; Oda, M.; Miyamoto, S.; Sonoda, S.; Tomono, D.; Miuchi, K.; Kurosawa, S.; Sawano, T.

    2016-07-01

    The field of MeV gamma-ray astronomy has not opened up until recently owing to imaging difficulties. Compton telescopes and coded-aperture imaging cameras are used as conventional MeV gamma-ray telescopes; however their observations are obstructed by huge background, leading to uncertainty of the point spread function (PSF). Conventional MeV gamma-ray telescopes imaging utilize optimizing algorithms such as the ML-EM method, making it difficult to define the correct PSF, which is the uncertainty of a gamma-ray image on the celestial sphere. Recently, we have defined and evaluated the PSF of an electron-tracking Compton camera (ETCC) and a conventional Compton telescope, and thereby obtained an important result: The PSF strongly depends on the precision of the recoil direction of electron (scatter plane deviation, SPD) and is not equal to the angular resolution measure (ARM). Now, we are constructing a 30 cm-cubic ETCC for a second balloon experiment, Sub-MeV gamma ray Imaging Loaded-on-balloon Experiment: SMILE-II. The current ETCC has an effective area of 1 cm2 at 300 keV, a PSF of 10° at FWHM for 662 keV, and a large field of view of 3 sr. We will upgrade this ETCC to have an effective area of several cm2 and a PSF of 5° using a CF4-based gas. Using the upgraded ETCC, our observation plan for SMILE-II is to map of the electron-positron annihilation line and the 1.8 MeV line from 26Al. In this paper, we will report on the current performance of the ETCC and on our observation plan.

  1. High resolution inelastic gamma-ray measurements with a white neutron source from 1 to 200 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, R.O.; Laymon, C.M.; Wender, S.A.

    1990-01-01

    Measurements of prompt gamma rays following neutron-induced reactions have recently been made at the spallation neutron source at the WNR target area of LAMPF using germanium detectors. These experiments provide extensive excitation function data for inelastic neutron scattering as well as for other reactions such as (n,{alpha}), (n,n{alpha}), (n,p), (n,np), (n,nnp) and (n,xn) for 1 {le} {times} {le} 11. The continuous energy coverage available from 1 MeV to over 200 MeV is ideal for excitation function measurements and greatly extends the energy range for such data. The results of these measurements will provide a database for interpretation of gamma-ray spectra from the planned Mars Observer mission, aid in radiation transport calculations, allow verification of nuclear reaction models, and improve the evaluated neutron reaction data base.

  2. High resolution inelastic gamma-ray measurements with a white neutron source from 1 to 200 MeV

    International Nuclear Information System (INIS)

    Nelson, R.O.; Laymon, C.M.; Wender, S.A.

    1990-01-01

    Measurements of prompt gamma rays following neutron-induced reactions have recently been made at the spallation neutron source at the WNR target area of LAMPF using germanium detectors. These experiments provide extensive excitation function data for inelastic neutron scattering as well as for other reactions such as (n,α), (n,nα), (n,p), (n,np), (n,nnp) and (n,xn) for 1 ≤ x ≤ 11. The continuous energy coverage available from 1 MeV to over 200 MeV is ideal for excitation function measurements and greatly extends the energy range for such data. The results of these measurements will provide a database for interpretation of gamma-ray spectra from the planned Mars Observer mission, aid in radiation transport calculations, allow verification of nuclear reaction models, and improve the evaluated neutron reaction data base

  3. Design and simulation of a 1.2MeV electron accelerator used for desulfuration and denitrogenation

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, J.; Zhu, D.J.; Liu, S.G.; Wang, H.B.; Xu, Z.; Liu, X.S. [University of Electrical Science & Technology of China, Chengdu (China)

    2005-07-01

    This paper presents the structural design and functional analysis of a new kind of 1.2MeV industrial electron accelerator. PIC (Particle-In-Cell) method is used to simulate this accelerator and to optimize the design. The results show that the optics property of this accelerator has been improved. This electron accelerator is used for desulfurisation and denitrification in environmental industry. This application purifies flue gases of the thermal power stations from sulphur oxide and nitrogen oxides in order to reduce air pollution.

  4. Electron angular distributions in He single ionization impact by H2+ ions at 1 MeV

    International Nuclear Information System (INIS)

    Zhang Shaofeng; Ma Xinwen; Suske, J; Fischer, D; Kuehnel, K U; Voitkiv, A; Najjaril, B; Krauss, A; Moshammer, R; Ullrich, J; Hagmann, S

    2009-01-01

    For the first time we investigated in a kinematically complete experiment the ionization of helium in collisions with H 2 + -molecular ions at 1 MeV. Using two separate detectors, the orientation of the projectile H 2 + -molecular ions was determined at the instance of the collision. The electron angular distribution was measured by a R eaction Microscope . The observed structures are found in agreement with theoretical calculations, indicating that the ionized electron of He shows a slight preferential emission direction parallel to the molecular axis.

  5. Test calculations of photoneutrons emission from surface of uranium sphere irradiated by 28 MeV electrons

    International Nuclear Information System (INIS)

    Blokhin, A.I.; Degtyarev, I.I.

    2002-01-01

    In this paper the results of physical verification for the BOFOD photonuclear data files are reported, available for the uranium isotopes U 235 , U 238 . These results were compared with calculated data by the parameterization driven model of photonuclear reaction and experimental data. Experimental data of photoneutron yields from surface of uranium sphere irradiated by 28 MeV electrons are used for a verification. Both calculations have been carried out with the RTS and T general purpose Monte Carlo code with detailed electron-photon-nucleon transport simulation using the ENDF/B-VI and EPDL evaluated data libraries

  6. Design and simulation of a 1.2 MeV electron accelerator used for desulfuration and denitrogenation

    International Nuclear Information System (INIS)

    Zhou Jun; Zhu Dajun; Liu Shenggang

    2005-01-01

    This paper presents the structural design and functional analysis of a new kind of 1.2 MeV industrial electron accelerator. PIC (Particle-In-Cell) method is used to simulate this accelerator and to optimize the design, the results show that the optics property of this accelerator has been improved. This electron accelerator is used for desulfuration and denitrogenation in environmental industry. This application purifies flue gases of the thermal power station from Sulphurous oxide and Nitrogen oxide in order to reduce the pollution in the air. (author)

  7. 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...... materials within a Z-range of 13–82. A linear relation is found between bremsstrahlung dose and electron dose ranging from 2 to 20 Mrad. Finally the effect of converter area on detector response is studied....

  8. Variation of oxygen enhancement ratio with radiation dose studies using 8 MeV electron beam

    International Nuclear Information System (INIS)

    Yerol, Narayana; Nairy, Rajesha K.; Sanjeev, Ganesh

    2014-01-01

    The radiobiological effects can be modified by physical, chemical and biological factors. Oxygen is one of the best known modifiers, and the biological effects are greater in the presence of oxygen. Failure to achieve complete response following radiotherapy of large tumors is attributed to the presence of radio-resistant hypoxic cells; therefore clarifying the mechanism of the oxygen effect is important. In the present study, an attempt was made to quantify Oxygen Enhancement Ratio (OER) and variation of OER as a function of dose with experimental and theoretical formulations using Saccharomyces cerevisiae D7, X2180 and rad 52 and 8 MeV electron beam from Microtron accelerator. The single cell stationary-phase cultures were obtained by growing the cells in Yeast extract: Peptone: Dextrose (YEPD) (1%:2%:2%) medium for several generations in stationary phase to a density of approximately 3 x 10 8 cells mL -1 . Cells were washed thrice by centrifugation and re-suspended to a cell concentration of 1 x 10 8 cells mL -1 in a sterile polypropylene vial for irradiation. Hypoxic conditions were achieved by incubating the samples in air tight vials at 30℃ for 30 min prior to irradiation. For euoxic samples, a cell suspension of 1 x 10 6 cells mL -1 was prepared and was thoroughly aerated by mixing before irradiation. Treated and untreated samples were suitably diluted and plated in quadruplicate on YEPD agar medium. Plates were incubated for 2-3 days at 30℃ in dark and normal atmospheric conditions and the colonies were counted. The study confirmed that, the variation of OER with dose depends upon type of cell and repair proficiency of cells. For repair proficient cells OER value has been found to increase with dose, while remain constant for repair deficient cell lines. A theoretical model has been formulated to estimate OER values. The OER value varies from 1.51 to 2.53 for D7, 2.02 to 2.98 for X2180, and 2.58 for rad 52. (author)

  9. A novel source of MeV positron bunches driven by energetic protons for PAS application

    Energy Technology Data Exchange (ETDEWEB)

    Tan, Zongquan, E-mail: tqq1123@mail.ustc.edu.cn [State Key Laboratory of Particle Detection and Electronics, University of Science and Technology of China, Hefei, Anhui 230026 (China); Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026 (China); Xu, Wenzhen; Liu, Yanfen; Xiao, Ran; Kong, Wei [State Key Laboratory of Particle Detection and Electronics, University of Science and Technology of China, Hefei, Anhui 230026 (China); Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026 (China); Ye, Bangjiao, E-mail: bjye@ustc.edu.cn [State Key Laboratory of Particle Detection and Electronics, University of Science and Technology of China, Hefei, Anhui 230026 (China); Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026 (China)

    2014-11-01

    This paper proposes a novel methodology of MeV positrons generation for PAS application. Feasibility of this proposal analyzed by G4Beamline and Transport have shown reasonable success. Using 2 Hz, 1.6 GeV, 100 ns and 1.5 μC/bunch proton bunches for bombarding a graphite target, about 100 ns e{sup +} bunches are generated. Quasi-monochromatic positrons in the range of 1–10 MeV included in these bunches have a flux of >10{sup 7}/s, peak brightness of 10{sup 14}/s. A magnetic-confinement beamline is utilized to transport the positrons and a “Fast Beam Chopper” is unprecedentedly extended to chop those relativistic bunches. The positron beam can be finally characterized by the energy range of 1–10 MeV and bunch width from one hundred ps up to 1 ns. Such ultrashort bunches can be useful in tomography-type positron annihilation spectroscopy (PAS) as well as other applications.

  10. A novel source of MeV positron bunches driven by energetic protons for PAS application

    Science.gov (United States)

    Tan, Zongquan; Xu, Wenzhen; Liu, Yanfen; Xiao, Ran; Kong, Wei; Ye, Bangjiao

    2014-11-01

    This paper proposes a novel methodology of MeV positrons generation for PAS application. Feasibility of this proposal analyzed by G4Beamline and Transport have shown reasonable success. Using 2 Hz, 1.6 GeV, 100 ns and 1.5 μC/bunch proton bunches for bombarding a graphite target, about 100 ns e+ bunches are generated. Quasi-monochromatic positrons in the range of 1-10 MeV included in these bunches have a flux of >107/s, peak brightness of 1014/s. A magnetic-confinement beamline is utilized to transport the positrons and a "Fast Beam Chopper" is unprecedentedly extended to chop those relativistic bunches. The positron beam can be finally characterized by the energy range of 1-10 MeV and bunch width from one hundred ps up to 1 ns. Such ultrashort bunches can be useful in tomography-type positron annihilation spectroscopy (PAS) as well as other applications.

  11. Dosimetric evaluation of multi-sided irradiation on HDPE pipes under 2 MeV electron beam

    Energy Technology Data Exchange (ETDEWEB)

    Benny, P.G., E-mail: bennypg@yahoo.com; Khader, S.A.; Sarma, K.S.S.

    2014-03-01

    The use of electron beam technology has enabled the production of heat resistant pipe for hot water circulation. One of the difficulties in the irradiation of pipe products is the uneven penetration of electrons. Quality of the radiation process depends on radiation dose and homogeneity of the dose distribution, which becomes a major concern when treatments of circular objects like pipes are performed. One method to achieve uniformity in the absorbed dose in the product is to use multi-sided irradiation. The paper discusses the importance of dosimetry mapping in industrial electron beam radiation processing and outlines the challenges in delivering a uniform dose to cylindrical objects. In this study, HDPE pipe of 5 mm thickness of homogeneous material (40 mm outer diameter and 30 mm inner diameter) has been chosen for multi-sided irradiation under 2 MeV scanned electron beam from the ILU-6 accelerator. - Highlights: • The paper outlines the challenges in delivering uniform dose to cylindrical objects at 2 MeV industrial electron beam facility. • HDPE pipe of 40 mm outer diameter and 30 mm inner diameter has been chosen for the study. • The circumferential dose distribution inside and outside of the pipes were evaluated by using calibrated CTA dosimeter strips. • Using stack of dosimeter strips, changes in circumferential dose distribution in the annular region of the pipe was evaluated. • Optimization of multi-sided irradiation on the HDPE pipes for better dose homogeneity is reported in the paper.

  12. Dosimetric evaluation of multi-sided irradiation on HDPE pipes under 2 MeV electron beam

    International Nuclear Information System (INIS)

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

    2014-01-01

    The use of electron beam technology has enabled the production of heat resistant pipe for hot water circulation. One of the difficulties in the irradiation of pipe products is the uneven penetration of electrons. Quality of the radiation process depends on radiation dose and homogeneity of the dose distribution, which becomes a major concern when treatments of circular objects like pipes are performed. One method to achieve uniformity in the absorbed dose in the product is to use multi-sided irradiation. The paper discusses the importance of dosimetry mapping in industrial electron beam radiation processing and outlines the challenges in delivering a uniform dose to cylindrical objects. In this study, HDPE pipe of 5 mm thickness of homogeneous material (40 mm outer diameter and 30 mm inner diameter) has been chosen for multi-sided irradiation under 2 MeV scanned electron beam from the ILU-6 accelerator. - Highlights: • The paper outlines the challenges in delivering uniform dose to cylindrical objects at 2 MeV industrial electron beam facility. • HDPE pipe of 40 mm outer diameter and 30 mm inner diameter has been chosen for the study. • The circumferential dose distribution inside and outside of the pipes were evaluated by using calibrated CTA dosimeter strips. • Using stack of dosimeter strips, changes in circumferential dose distribution in the annular region of the pipe was evaluated. • Optimization of multi-sided irradiation on the HDPE pipes for better dose homogeneity is reported in the paper

  13. Ultrafast electron diffraction using an ultracold source

    Directory of Open Access Journals (Sweden)

    M. W. van Mourik

    2014-05-01

    Full Text Available The study of structural dynamics of complex macromolecular crystals using electrons requires bunches of sufficient coherence and charge. We present diffraction patterns from graphite, obtained with bunches from an ultracold electron source, based on femtosecond near-threshold photoionization of a laser-cooled atomic gas. By varying the photoionization wavelength, we change the effective source temperature from 300 K to 10 K, resulting in a concomitant change in the width of the diffraction peaks, which is consistent with independently measured source parameters. This constitutes a direct measurement of the beam coherence of this ultracold source and confirms its suitability for protein crystal diffraction.

  14. [International Panel on 14 MeV Intense Neutron Source Based on Accelerators for Fusion Materials Study

    International Nuclear Information System (INIS)

    Thoms, K.R.; Wiffen, F.W.

    1991-01-01

    Both travelers were members of a nine-person US delegation that participated in an international workshop on accelerator-based 14 MeV neutron sources for fusion materials research hosted by the University of Tokyo. Presentations made at the workshop reviewed the technology developed by the FMIT Project, advances in accelerator technology, and proposed concepts for neutron sources. One traveler then participated in the initial meeting of the IEA Working Group on High Energy, High Flux Neutron Sources in which efforts were begun to evaluate and compare proposed neutron sources; the Fourth FFTF/MOTA Experimenters' Workshop which covered planning and coordination of the US-Japan collaboration using the FFTF reactor to irradiate fusion reactor materials; and held discussions with several JAERI personnel on the US-Japan collaboration on fusion reactor materials

  15. /sup 1/H(t,n)/sup 3/He reaction as monoenergetic neutron source in the (10/20) MeV energy interval

    Energy Technology Data Exchange (ETDEWEB)

    Zago, G. (Padua Univ. (Italy). Ist. di Fisica; Istituto Nazionale di Fisica Nucleare, Padua (Italy))

    1981-11-14

    This article examines the problem of finding a neutron source in the (10/20) MeV energy interval, having convenient properties for controlled thermonuclear-fusion researches and biomedical applications.

  16. Electron cyclotron resonance multiply charged ion sources

    International Nuclear Information System (INIS)

    Geller, R.

    1975-01-01

    Three ion sources, that deliver multiply charged ion beams are described. All of them are E.C.R. ion sources and are characterized by the fact that the electrons are emitted by the plasma itself and are accelerated to the adequate energy through electron cyclotron resonance (E.C.R.). They can work without interruption during several months in a quasi-continuous regime. (Duty cycle: [fr

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

    International Nuclear Information System (INIS)

    Korenev, S.A.

    1994-01-01

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

  18. Versatile spin-polarized electron source

    Science.gov (United States)

    Jozwiak, Chris; Park, Cheol -Hwan; Gotlieb, Kenneth; Louie, Steven G.; Hussain, Zahid; Lanzara, Alessandra

    2015-09-22

    One or more embodiments relate generally to the field of photoelectron spin and, more specifically, to a method and system for creating a controllable spin-polarized electron source. One preferred embodiment of the invention generally comprises: method for creating a controllable spin-polarized electron source comprising the following steps: providing one or more materials, the one or more materials having at least one surface and a material layer adjacent to said surface, wherein said surface comprises highly spin-polarized surface electrons, wherein the direction and spin of the surface electrons are locked together; providing at least one incident light capable of stimulating photoemission of said surface electrons; wherein the photon polarization of said incident light is tunable; and inducing photoemission of the surface electron states.

  19. 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.

  20. An automatic frequency control system of 2-MeV electronic LINAC

    International Nuclear Information System (INIS)

    Hu Xue; Zhang Junqiang; Zhong Shaopeng; Zhao Minghua

    2013-01-01

    Background: In electronic LINAC, the magnetron is often used as power source. The output frequency of magnetron always changes with the environment and the frequency difference between the output of magnetron and the frequency of accelerator, which will result in the bad performance of LINAC systems. Purpose: To ensure the performance of the work of entire LINAC system effectively, an automatic frequency control system is necessary. Methods: A phase locked frequency discriminator is designed to discriminate the frequency of accelerator guide and magnetron, and analogue circuit is used to process the output signals of frequency discriminator unit. Results: Working with the automatic frequency control (AFC) system, the output frequency of magnetron can be controlled in the range of (2998 MHz, 2998 MHz + 70 kHz) and (2998 MHz, 2998 MHz - 30 kHz). Conclusions: Under the measurement and debug, the functionality of frequency discriminator unit and signal processor circuit is tested effectively. (authors)

  1. Field uses of a portable 4/6 MeV electron linear accelerator

    International Nuclear Information System (INIS)

    Schonberg, R.G.

    1987-01-01

    The portable electron linear accelerator which was developed on Electric Power Research Institute funds was targeted to provide an additional inspection tool for the nuclear power industry. The results have justified the expense in cost savings by reducing unnecessary repairs and in demonstrating integrity of some critical welds in pump bodies. The minac (miniature accelerator) has proven effective in cases where other inspection techniques have been ineffective, such as cast stainless steel pump bodies and overlay clad welds. Other applications, such as dynamic imaging of rocket motor test firings and field inspection of pressure vessels, will be reported. A description of the equipment, the method of field operation and the special safety problems related to a high intensity radiation source without containment will be discussed. (orig.)

  2. Characterization of 10 MeV electron linac for radiation processing

    International Nuclear Information System (INIS)

    Petwal, V.C.; Rao, J.N.; Kaul, A.; Bapna, S.C.; Mulchandani, J.K.; Wanmode, Y.; Pandiyar, M.; Srivastava, P.; Jain, Akhilesh; Hanurkar, P.R.

    2006-01-01

    A radiation processing facility based on a 10 MeV LINAC is being set-up at RRCAT. In the course of commissioning various experiments have been carried-out to characterize the radiation field generated by the accelerator and subsequently to derive the operating parameters of the facility for radiation processing of various items. Results of the experiments are presented in the paper. (author)

  3. 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

  4. Annual seminar on electronic sources of information

    International Nuclear Information System (INIS)

    Ravichandra Rao, I.K.

    2000-03-01

    With the rapid development in IT and the emergence of Internet, a multitude of information sources are now available on electronic media. They include e-journals and other electronic publications - online databases, reference documents, newspapers, magazines, etc. In addition to these online sources, there are thousands of CD-ROM databases. The CD-ROM databases and the online sources are collectively referred to as electronic sources of information. Libraries in no part of the world can afford to ignore these sources. Emergence of these new sources has resulted into a change in the traditional library functions including collection development, acquisitions, cataloguing, user instructions, etc. It is inevitable that in the next five to ten years, special libraries may have to allocate considerable amount towards subscription of e-journals and other e-publications. The papers in this seminar volume discuss several aspects related the theme of the seminar and cover e-journals, different sources available in the Net, classification of electronic sources, online public access catalogues, and different aspects of Internet. Papers relevant to INIS are indexed separately

  5. Electron-cyclotron-resonance ion sources (review)

    International Nuclear Information System (INIS)

    Golovanivskii, K.S.; Dougar-Jabon, V.D.

    1992-01-01

    The physical principles are described and a brief survey of the present state is given of ion sources based on electron-cyclotron heating of plasma in a mirror trap. The characteristics of ECR sources of positive and negative ions used chiefly in accelerator technology are presented. 20 refs., 10 figs., 3 tabs

  6. Ion-source dependence of the distributions of internuclear separations in 2-MeV HeH+ beams

    International Nuclear Information System (INIS)

    Kanter, E.P.; Gemmell, D.S.; Plesser, I.; Vager, Z.

    1981-01-01

    Experiments involving the use of MeV molecular-ion beams have yielded new information on atomic collisions in solids. A central part of the analyses of such experiments is a knowledge of the distribution of internuclear separations contained in the incident beam. In an attempt to determine how these distributions depend on ion-source gas conditions, we have studied foil-induced dissociations of H 2+ , H 3+ , HeH + , and OH 2+ ions. Although changes of ion-source gas compositions and pressure were found to have no measurable influence on the vibrational state populations of the beams reaching our target, for HeH + we found that beams produced in our rf source were vibrationally hotter than beams produced in a duoplasmatron. This was also seen in studies of neutral fragments and transmitted molecules

  7. A study on virtual source position for electron beams from a Mevatron MD linear accelerator

    International Nuclear Information System (INIS)

    Ravindran, B.P.

    1999-01-01

    The virtual source position (VSP) for electron beams of energies 5, 7, 9 10, 12 and 14 MeV and for the applicators (cones) available in the department have been measured for a Mevatron MD class linear accelerator. Different methods of obtaining the virtual source position for electron beams have been investigated in the present study. The results obtained have been compared with those of other workers. It is observed that the VSP is very much machine dependent and needs to be measured for each linear accelerator. The effect of shielding on virtual source position for the type of applicators available in the department has also been investigated. (author)

  8. Direct determination of k Q factors for cylindrical and plane-parallel ionization chambers in high-energy electron beams from 6 MeV to 20 MeV

    Science.gov (United States)

    Krauss, A.; Kapsch, R.-P.

    2018-02-01

    For the ionometric determination of the absorbed dose to water, D w, in high-energy electron beams from a clinical accelerator, beam quality dependent correction factors, k Q, are required. By using a water calorimeter, these factors can be determined experimentally and potentially with lower standard uncertainties than those of the calculated k Q factors, which are tabulated in various dosimetry protocols. However, one of the challenges of water calorimetry in electron beams is the small measurement depths in water, together with the steep dose gradients present especially at lower energies. In this investigation, water calorimetry was implemented in electron beams to determine k Q factors for different types of cylindrical and plane-parallel ionization chambers (NE2561, NE2571, FC65-G, TM34001) in 10 cm  ×  10 cm electron beams from 6 MeV to 20 MeV (corresponding beam quality index R 50 ranging from 1.9 cm to 7.5 cm). The measurements were carried out using the linear accelerator facility of the Physikalisch-Technische Bundesanstalt. Relative standard uncertainties for the k Q factors between 0.50% for the 20 MeV beam and 0.75% for the 6 MeV beam were achieved. For electron energies above 8 MeV, general agreement was found between the relative electron energy dependencies of the k Q factors measured and those derived from the AAPM TG-51 protocol and recent Monte Carlo-based studies, as well as those from other experimental investigations. However, towards lower energies, discrepancies of up to 2.0% occurred for the k Q factors of the TM34001 and the NE2571 chamber.

  9. Direct determination of k Q factors for cylindrical and plane-parallel ionization chambers in high-energy electron beams from 6 MeV to 20 MeV.

    Science.gov (United States)

    Krauss, A; Kapsch, R-P

    2018-02-06

    For the ionometric determination of the absorbed dose to water, D w , in high-energy electron beams from a clinical accelerator, beam quality dependent correction factors, k Q , are required. By using a water calorimeter, these factors can be determined experimentally and potentially with lower standard uncertainties than those of the calculated k Q factors, which are tabulated in various dosimetry protocols. However, one of the challenges of water calorimetry in electron beams is the small measurement depths in water, together with the steep dose gradients present especially at lower energies. In this investigation, water calorimetry was implemented in electron beams to determine k Q factors for different types of cylindrical and plane-parallel ionization chambers (NE2561, NE2571, FC65-G, TM34001) in 10 cm  ×  10 cm electron beams from 6 MeV to 20 MeV (corresponding beam quality index R 50 ranging from 1.9 cm to 7.5 cm). The measurements were carried out using the linear accelerator facility of the Physikalisch-Technische Bundesanstalt. Relative standard uncertainties for the k Q factors between 0.50% for the 20 MeV beam and 0.75% for the 6 MeV beam were achieved. For electron energies above 8 MeV, general agreement was found between the relative electron energy dependencies of the k Q factors measured and those derived from the AAPM TG-51 protocol and recent Monte Carlo-based studies, as well as those from other experimental investigations. However, towards lower energies, discrepancies of up to 2.0% occurred for the k Q factors of the TM34001 and the NE2571 chamber.

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

    International Nuclear Information System (INIS)

    Kulkarni, Nita S.; Dhingra, Rinky; Kumar, Vinit

    2016-01-01

    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 2π/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. Three dimensional transient simulations of the accelerating structure along with the input and output couplers have been performed using the software CST-MWS to explicitly demonstrate this feature. (author)

  11. Effect of cellular glutathione content on the induction of DNA double strand breaks by 25 MeV electrons

    Energy Technology Data Exchange (ETDEWEB)

    Frankenberg, D.; Kistler, M.; Eckhardt-Schupp, F.

    1987-08-01

    The effect of endogenous glutathione (GSH) on the induction of DNA double strand breaks (dsb) by 25 MeV electrons was investigated using stationary haploid yeast cells defective in ..gamma..-glutamyl-cysteine-synthetase (gsh 1) containing less than 5 per cent of the normal GSH content. In gsh 1 cells the induction of dsb is increased by a factor of 1.5 under oxic and 1.8 under anoxic irradiation conditions whereas the oxygen enhancement ratio was only slightly decreased (1.9) compared to wild-type cells (2.4).

  12. Effect of cellular glutathione content on the induction of DNA double strand breaks by 25 MeV electrons

    International Nuclear Information System (INIS)

    Frankenberg, D.; Kistler, M.; Eckhardt-Schupp, F.

    1987-01-01

    The effect of endogenous glutathione (GSH) on the induction of DNA double strand breaks (dsb) by 25 MeV electrons was investigated using stationary haploid yeast cells defective in γ-glutamyl-cysteine-synthetase (gsh 1) containing less than 5 per cent of the normal GSH content. In gsh 1 cells the induction of dsb is increased by a factor of 1.5 under oxic and 1.8 under anoxic irradiation conditions whereas the oxygen enhancement ratio was only slightly decreased (1.9) compared to wild-type cells (2.4). (author)

  13. Shielding Calculations for Industrial 5/7.5MeV Electron Accelerators Using the MCNP Monte Carlo Code

    International Nuclear Information System (INIS)

    Peri, E.; Orion, I.

    2014-01-01

    High energy X-rays from accelerators are used to irradiate food ingredients to prevent growth and development of unwanted biological organisms in food, in order to extend the shelf life of products. High energy photons can cause food activation due to (D 3 ,n) reactions. Until 2004, to eliminate the possibility of food activation, the electron energy was limited to 5 MeV X-rays for food irradiation. In 2004, the FDA approved the usage of up to 7.5 MeV, but only with tantalum and gold targets (1). Higher X-ray energy results an increased flux of X-rays in the forward direction, increased penetration, and higher photon dose rate due to better electron-to-photon conversion. These improvements could decrease the irradiation time and allow irradiation of larger packages, thereby providing higher production rates with lower treatment cost. Medical accelerators usually work with 6-18 MV electron energy with tungsten target to convert the electron beam to X-rays. In order to protect the patients, the accelerator head is protected with a heavy lead shielding; therefore, the bremsstrahlung is emitted only in the forward direction. There are many publications and standards that guide how to design optimal shielding for medical accelerator rooms. The shielding data for medical accelerators is not applicable for industrial accelerators, since the data is for different conversion targets, different X-Ray energies, and only for the forward direction. Collimators are not always in use in industrial accelerators, and therefore bremsstrahlung photons can be emitted in all directions. The bremsstrahlung spectrum and dose rate change as a function of the emission angle. The dose rate decreases from maximum in the forward direction (0°) to minimum at 180° by 1-2 orders of magnitude. In order to design and calculate optimal shielding for food accelerator rooms, there is a need to have the bremsstrahlung spectrum data, dose rates and concrete attenuation data in all emission directions

  14. Enacting laws concerning radiation safety management for students using X-rays and electron beams under 1 MeV

    International Nuclear Information System (INIS)

    Nishizawa, Kunihide; Shibata, Michihiro; Saze, Takuya

    2004-01-01

    Laws concerning radiation safety management were analyzed from the point of view of defining precisely what is meant by radiation and what is meant by the subject. There are no laws to protect students from radiation hazards when using X-rays and electron beams under 1 MeV for research and/or education. The Law concerning Technical Standards for Preventing Radiation Hazards gives the authorities the power to enact new rules and regulations that will protect the students. The Radiation Council must take charge for enactment of all laws regarding radiation safety management. (author)

  15. Lactose and sucrose aqueous solutions for high-dose dosimetry with 10-MeV electron beam irradiation

    International Nuclear Information System (INIS)

    Amraei, R.; Kheirkhah, M.; Raisali, G.

    2012-01-01

    In the present study, dosimetric characterisation of aqueous solutions of lactose and sucrose was analysed by UV spectrometry following irradiation using 10-MeV electron beam at doses between 0.5 and 10.5 kGy. As a dosimetric index, absorbance is selected at 256 and 264 nm for lactose and sucrose aqueous solutions, respectively. The intensity of absorbance for irradiated solutions depends on the pre-irradiation concentration of lactose and sucrose. The post-irradiation stability of both solutions was investigated at room temperature for a measurement period of 22 d. (authors)

  16. Influence of 2 MeV electrons irradiation on gallium phosphide light-emitting diodes reverse currents

    Directory of Open Access Journals (Sweden)

    V. G. Vorobiov

    2015-10-01

    Full Text Available Results of reverse electrophysical characteristics study of red and green LEDs, initial and irradiated with 2 MeV electrons were given. It was found that reverse current was predominantly caused by carriers tunneling at Urev ≤ 9 V, and by the avalanche multiplication at Urev ≥ 13 V, in the range U = 9 ÷ 13 V both mechanisms are available. Current increase at high voltage areas (Urev > 19 V is limited by the base resistance of diode. In the case of significant reverse currents (I > 1 mA irradiation of diodes leads to the shift of reverse current-voltage characteristics into the high voltages direction.

  17. Estimation of the measurement effective point in cylindrical ionization chamber used in electron beams with energies between 6 and 20 MeV

    International Nuclear Information System (INIS)

    Araujo, M.M. de.

    1984-01-01

    The radial displacement was determined in a water phantom for electrons beams at energies from 6 to 20 MeV for three commercial cylindrical ionization chambers of internal diameters varying from 3.5 to 9.0 mm. The chambers were irradiated with the main axis perpendicular to the direction of the beam. A 300 V bias voltage was applied and readings were taken with both polarities. It was observed that, with increasing depth in the water phantom, the radial displacement remains constant for the 8.9 MeV beam, it increases for the 12.6 MeV electrons and decreases for those of 16.8 and 19.7 MeV. A theoretical model was built in order to calculate the displacement of the effective point of measurement. The Fermi-Eyges multiple scattering theory and a retangular beam normalism developed by Jette (1983) for therapeutic electron beam are used. It was found that the radial displacement stays constant with increasing depth and it decreases with increasing average energy of the incident beam. The model also predicts that the displacement is dependent on the chamber radius. The experimental and theoretical results are compared. They show good agreement for 8.9 and 12.6 MeV electrons, while for 16.8 and 19.7 MeV electrons they indicate that modifications in the theoretical model are necessary. (Author) [pt

  18. High power pulsed/microwave technologies for electron accelerators vis a vis 10MeV, 10kW electron LINAC for food irradiation at CAT

    International Nuclear Information System (INIS)

    Shrivastava, Purushottam; Mulchandani, J.; Mohania, P.; Baxy, D.; Wanmode, Y.; Hannurkar, P.R.

    2005-01-01

    Use of electron accelerators for irradiation of food items is gathering momentum in India. The various technologies for powering the electron LINAC were needed to be developed in the country due to embargo situations as well as reservations of the developers worldwide to share the information related to this development. Centre for Advanced Technology, CAT, Indore, is engaged in the development of particle accelerators for medical industrial and scientific applications. Amongst other electron accelerators developed in CAT, a 10MeV, 10kW LINAC for irradiation of food items has been commissioned and tested for full rated 10kW beam power. The high power pulsed microwave driver for the LINAC was designed, developed and commissioned with full indigenous efforts, and is right now operational at CAT. It consists of a 6MW, 25kW S-band pulsed klystron, 15MW peak power pulse modulator system for the klystron, microwave driver amplifier chain, stabilized generator, protection and control electronics, waveguide system to handle the high peak and average power, gun modulator electronics, grid electronics etc. The present paper highlights various technologies like the pulsed power systems and components, microwave circuits and systems etc. Also the performance results of the high power microwave driver for the 10MeV LINAC at CAT are discussed. Future strategies for developing the state of art technologies are highlighted. (author)

  19. Spectrum of neutrons leaking from an iron sphere with a central 14 MeV neutron source

    International Nuclear Information System (INIS)

    Borisov, A.A.; Zagryadskij, V.A.; Chuvilin, D.Yu.; Kralik, M.; Pulpan, J.; Tichy, M.

    1991-01-01

    Following a review of the present state of nuclear data requisite for the calculation of the transport of 14 MeV neutrons through iron of natural isotopic composition, the results are given of the calculation of the energy spectrum of such neutrons after their passage through an iron sphere 240 mm o.d. and 90 mm i.d., the neutron source being accommodated in the centre of the sphere. The calculations were made using the one-dimensional code BLANK working with the nuclear data libraries ENDL-75, ENDL-83, ENDL/B-IV, JENDL-2 and BROND, and using the three-dimensional code BRAND with the library ENDL-78. The calculated spectra were compared with the experimental spectrum measured at a distance of 3 m from the sphere by means of an NE-213 scintillator, which records reflected protons. The reflected proton spectrum was processed by the matrix method (program FORIST), and the result was normalized to one neutron emitted by the source, as were the calculated spectra. The comparison demonstrates that the experiment is best fitted by the spectrum calculated by using the library JENDL-2, where the integrals of the observed and calculated spectra over the 1-15 MeV range differ as little as approximately 10%. (author). 3 figs., 5 tabs., 16 refs

  20. Radiation safety considerations for operation of a portable 6 MeV electron linear accelerator

    International Nuclear Information System (INIS)

    Schonberg, R.G.

    1987-01-01

    Field use of the ''MINAC'' presents some unique problems. There are some high voltage electrical safety problems, but these pale in comparison to the radiation related problems. The perimeter limits are determined by a combination of leakage and scatter. In most cases, the boundary limit is determined by scatter. Localized shielding can be applied to reduce scatter which is primarily of rest-mass energy (0.511 MeV). Careful primary beam collimating can also be used to reduce the radiation hazard

  1. Simulation of enhanced characteristic x rays from a 40-MeV electron beam laser accelerated in plasma

    Directory of Open Access Journals (Sweden)

    L. Nikzad

    2012-02-01

    Full Text Available Simulation of x-ray generation from bombardment of various solid targets by quasimonoenergetic electrons is considered. The electron bunches are accelerated in a plasma produced by interaction of 500 mJ, 30 femtosecond laser pulses with a helium gas jet. These relativistic electrons propagate in the ion channel generated in the wake of the laser pulse. A beam of MeV electrons can interact with targets to generate x-ray radiation with keV energy. The MCNP-4C code based on Monte Carlo simulation is employed to compare the production of bremsstrahlung and characteristic x rays between 10 and 100 keV by using two quasi-Maxwellian and quasimonoenergetic energy distributions of electrons. For a specific electron spectrum and a definite sample, the maximum x-ray flux varies with the target thickness. Besides, by increasing the target atomic number, the maximum x-ray flux is increased and shifted towards a higher energy level. It is shown that by using the quasimonoenergetic electron profile, a more intense x ray can be produced relative to the quasi-Maxwellian profile (with the same total energy, representing up to 77% flux enhancement at K_{α} energy.

  2. 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)

  3. 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.

  4. 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.

  5. 14 MeV calibration of JET neutron detectors—phase 1: calibration and characterization of the neutron source

    Science.gov (United States)

    Batistoni, P.; Popovichev, S.; Cufar, A.; Ghani, Z.; Giacomelli, L.; Jednorog, S.; Klix, A.; Lilley, S.; Laszynska, E.; Loreti, S.; Packer, L.; Peacock, A.; Pillon, M.; Price, R.; Rebai, M.; Rigamonti, D.; Roberts, N.; Tardocchi, M.; Thomas, D.; Contributors, JET

    2018-02-01

    In view of the planned DT operations at JET, a calibration of the JET neutron monitors at 14 MeV neutron energy is needed using a 14 MeV neutron generator deployed inside the vacuum vessel by the JET remote handling system. The target accuracy of this calibration is  ±10% as also required by ITER, where a precise neutron yield measurement is important, e.g. for tritium accountancy. To achieve this accuracy, the 14 MeV neutron generator selected as the calibration source has been fully characterised and calibrated prior to the in-vessel calibration of the JET monitors. This paper describes the measurements performed using different types of neutron detectors, spectrometers, calibrated long counters and activation foils which allowed us to obtain the neutron emission rate and the anisotropy of the neutron generator, i.e. the neutron flux and energy spectrum dependence on emission angle, and to derive the absolute emission rate in 4π sr. The use of high resolution diamond spectrometers made it possible to resolve the complex features of the neutron energy spectra resulting from the mixed D/T beam ions reacting with the D/T nuclei present in the neutron generator target. As the neutron generator is not a stable neutron source, several monitoring detectors were attached to it by means of an ad hoc mechanical structure to continuously monitor the neutron emission rate during the in-vessel calibration. These monitoring detectors, two diamond diodes and activation foils, have been calibrated in terms of neutrons/counts within  ±5% total uncertainty. A neutron source routine has been developed, able to produce the neutron spectra resulting from all possible reactions occurring with the D/T ions in the beam impinging on the Ti D/T target. The neutron energy spectra calculated by combining the source routine with a MCNP model of the neutron generator have been validated by the measurements. These numerical tools will be key in analysing the results from the in

  6. Generation of 300 MeV Quasi-Monochromatic Electron Beams from Laser Wakefield and Initiation of Photonuclear Reactions

    Science.gov (United States)

    Maksimchuk, A.; Beene, J. R.

    2005-10-01

    In the interaction of 30 fs, 40 TW Ti:sapphire Hercules laser at the University of Michigan, which is focused to the intensity of 10^19 W/cm^2 onto a supersonic He gas jet with electron density close to the resonant density, we observed quasi-monoenergetic electron beams with energy up to 300 MeV and angular divergence of about 10 mrad. The results on characterization of relativistic electron beam in terms of energy spread, its charge, divergence and pointing stability will be presented. 2D PIC simulations performed for the parameters close to the experimental conditions show the evolution of the laser pulse in plasma, electron injection, and the specifics of electron acceleration observed in experiments. Resulted relativistic electron beams have been used to perform gamma-neutron activation of ^12C and ^63Cu and photo-fission of ^238U. We demonstrated that approximately 10^6 reaction per shot has been produced in each case. This work was supported by the NSF through the Physics Frontier Center FOCUS. JRB, DRS, DWS, and CRV acknowledge support by the DOE under contract DE-AC05-00OR22725 with UT-Battelle, LLC.

  7. 26-Day Variations of 7 MeV Electrons at high Latitudes and their Implications on the Heliospheric Magnetic Field

    Science.gov (United States)

    Sternal, Oliver; Engelbrecht, Eugene; Burger, Renier; Dunzlaff, Phillip; Ferreira, Stefan; Fichtner, Horst; Heber, Bernd; Kopp, Andreas; Potgieter, Marius; Scherer, Klaus

    The transport of energetic particles in the heliosphere is usually described by the Parker trans-port equation including the physical processes of diffusion, drift, convection and adiabatic energy changes. The Ulysses spacecraft provides unique insight into the flux of MeV electrons at high latitudes. In this contribution, we compare our model results for the Parker HMF model and the Fisk-type Schwadron-Parker HMF model to Ulysses measurements. The elec-tron flux at high latitudes has been used as a remote sensing method to investigate the imprint of a Fisk-type HMF. We show here for the first time that such an imprint exists and deduce a limitation on the Fisk HMF angle β.

  8. Microwave matching and tuning on the 20-MeV medical electron linac with feedback of rf power

    International Nuclear Information System (INIS)

    Yuan-ling, Wang

    1983-01-01

    This article describes the 20 Mev medical electron linac at Jiangsu Tumour Hospital. In the linac, feedback of rf power is used. In the linac with feedback (or with the resonator) the reflection affects the energy gain of the electron and the performance of the accelerator. By means of the theory of the traveling wave resonator, the field multiplication factor and the reflection coefficients inside and outside the feedback ring are calculated. The bands of the linacs without and with feedback are measured. In order to achieve a desirable band in front of the load (i.e. outside the feedback ring) a matching iris is added. After the linac with feedback has been matched, the band is given

  9. A directly heated electron beam line source

    International Nuclear Information System (INIS)

    Iqbal, M.; Masood, K.; Rafiq, M.; Chaudhry, M.A.

    2002-05-01

    A 140-mm cathode length, Electron Beam Line Source with a high degree of focusing of the beam is constructed. The design principles and basic characteristic considerations for electron beam line source consists of parallel plate electrode geometric array as well as a beam power of 35kW are worked out. The dimensions of the beam at the work site are 1.25xl00mm. The gun is designed basically for the study of evaporation and deposition characteristic of refractory metals for laboratory use. However, it may be equally used for melting and casting of these metals. (author)

  10. Study of the yield of the Fricke dosimetry for electron energies from 2 to 90 MeV

    International Nuclear Information System (INIS)

    Berkvens, I.P.

    1988-01-01

    The chemical yield for the ferrous sulphate dosimeters was determined for 60 Co-γ radiation and for electron beams of mean energies in the points of measurements, between 2.7 and about 9 MeV. As references, absolute determinations of absorbed dose based on calorimetric measurements, were used. The irradiation geometry for the ferrous sulphate dosimeter differ always due to technical reasons somewhat from that for the absorber of the calorimeter. The investigators took this difference into account. Perturbation correction factors that correct for the difference in electron scattering in the air gaps around the absorber of the calorimeter and in the graphite, were computed with the Monte Carlo method. Also the ''reference volume method'' recently introduced by the ICRU (report No.35), was applied to correct for the introduction of a ferrous sulphate dosimeter in a graphite phantom. This correction is necessary as the electrons are stopped and scattered in a different way in graphite and water. The results indicated that there is no energy dependence of the chemical yield (G-value) of the dosimeter in the energy range 2.7 to about 9 MeV. A mean G-value of 1,584 (± 0.006) μ mol/J was obtained. For 60 Co-γ a G-value of 1.601 μ mol/J was determined. However, this difference might not be real but due to the present uncertainty in the stopping-power ratios graphite to water. These ratios are thus made use of to determine the G-value from measurements of the absorbed dose to graphite. Previous investigations, by the group from Gent, indicated a small increase of the G-value with the electron energy. These more accurate determinations thus instead indicate a constant G-value. Refs, figs, tabs

  11. Bates GaAs polarized electron source

    International Nuclear Information System (INIS)

    Schaefer, H.R.; Cates, G.; Michaels, R.; Hughes, V.W.; Lubell, M.S.; Souder, P.A.

    1983-05-01

    In order to pursue measurements of parity violating effects of the neutral weak current, we have developed a polarized electron source suitable for installation at the MIT-Bates Linear Accelerator. The source is designed to provide a high peak-current pulsed beam that has a approx. 1% duty factor and that is extremely stable under helicity reversal. 34 references, 6 figures, 1 table

  12. Femtosecond electron bunches, source and characterization

    International Nuclear Information System (INIS)

    Thongbai, C.; Kusoljariyakul, K.; Rimjaem, S.; Rhodes, M.W.; Saisut, J.; Thamboon, P.; Wichaisirimongkol, P.; Vilaithong, T.

    2008-01-01

    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 σ z ∼180 fs with (1-6)x10 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

  13. The emittance and brightness characteristics of negative ion sources suitable for MeV ion implantation

    International Nuclear Information System (INIS)

    Alton, G.D.

    1987-01-01

    This paper provides the description and beam properties of ion sources suitable for use with ion implantation devices. Particular emphasis is placed on the emittance and brightness properties of state-of-the-art, high intensity, negative ion sources based on the cesium ion sputter principle

  14. 8 MeV electron beam induced modifications in the thermal, structural and electrical properties of nanophase CeO2 for potential electronics applications

    Science.gov (United States)

    Babitha, K. K.; Sreedevi, A.; Priyanka, K. P.; Ganesh, S.; Varghese, Thomas

    2018-06-01

    The effect of 8 MeV electron beam irradiation on the thermal, structural and electrical properties of CeO2 nanoparticles synthesized by chemical precipitation route was investigated. The dose dependent effect of electron irradiation was studied using various characterization techniques such as, thermogravimetric and differential thermal analyses, X-ray diffraction, Fourier transformed infrared spectroscopy and impedance spectroscopy. Systematic investigation based on the results of structural studies confirm that electron beam irradiation induces defects and particle size variation on CeO2 nanoparticles, which in turn results improvements in AC conductivity, dielectric constant and loss tangent. Structural modifications and high value of dielectric constant for CeO2 nanoparticles due to electron beam irradiation make it as a promising material for the fabrication of gate dielectric in metal oxide semiconductor devices.

  15. 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. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. Design study of a far-infrared free electron laser with a 20 MeV RF linear accelerator

    International Nuclear Information System (INIS)

    Nakata, S.; Tsukishima, C.; Hifumi, T.; Okuda, S.; Sato, S.; Yosojima, Y.

    1991-01-01

    A FEL in the far-infrared region has been designed using a low energy RF linear accelerator. First we estimate a small signal gain from spontaneous emission using the Madey's theorem. In the calculation following effects are included: an actual field distribution (using a measured magnetic field), beam envelope in the phase space through the undulator, energy spread, and electron beam mis-alignment to the undulator axis. We have developed a code which can simulate three dimensional processes of the electron interaction with multi-mode laser fields in the undulator. From this code we could obtain the time dependent bunching process of electrons and amplification of the laser field. During the calculation we assume an electron beam of 20 MeV, 100 mA with a pulse length of 3 μs, and an undulator of 28 periods, 6 cm periodic length and 2.5 kG peak field. The results from these calculations show that the small-signal gain over 40 % can be obtained, but mis-alignment of the beam severely degrades the gain. The results also show that the output power of several MW can be obtained under the above conditions. Considering the simulation results, a FEL beam line was constructed and the beam size at the undulator was measured. And electrons were focused enough for the FEL experiment. (author)

  17. An electron cooling device in the one MeV energy region

    International Nuclear Information System (INIS)

    Busso, L.; Tecchio, L.; Tosello, F.

    1987-01-01

    The project of an electron cooling device at 700 KeV electron energy is reported. The single parts of the device is described in detail. Electron beam diagnostics and technical problems is discussed. The electron gun, the accelerating/decelerating column and the collector have been studied by menas of the Herrmannsfeldt's program and at present are under construction. The high voltage system and the electron cooling magnet are also under construction. Vacuum tests with both hot and cold cathodes have demonstrated that the vacuum requirements can be attained by the use of non-evaporable getter (NEG) pumps between gun, collector and the cooling region. Both kinds of diagnostic for longitudinal and transversal electron temperature measurements are in progress. A first prototype of the synchronous picj-up was successfully tested at CERN SPS. At present the diagnostic with laser beam is in preparation. During the next year the device will be assembled and the laboratory test will be started

  18. 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.

  19. 2 MeV/20 kW industrial electron beam accelerator vis-s-vis its vacuum system

    International Nuclear Information System (INIS)

    Khader, S.A.; Assadullah, M.; Sarma, K.S.S.; Bandi, L.N.

    2003-01-01

    Full text: Electron beam accelerators in the energy range 200 keV to 10 MeV have been extensively used for many radiation processing applications that include polymerization, polymer modifications, radiation sterilization, food irradiation and gem coloration. The accelerator technology is a multidisciplinary one wherein production of stable vacuum in various accelerator systems is of utmost importance to achieve required output beam parameters like beam energy and current for processing industrial products at large through puts on continuous basis. A 2 MeV, 20 kW industrial electron beam accelerator has been in operation since 2001 at BARC-BRIT complex, Navi Mumbai for commercial and R and D applications like crosslinking of wire and cables, heat shrinkable tubes, PE O rings, PTEE degradation and color enhancement in diamonds. The machine is a ILU-6 type pulse RF accelerator consisting of a single resonator copper cavity of 1.2 m diameter and 1.2 m height (volume:∼ 1.5 m3) placed inside a stainless steel container (called cavity container) and a s.s. beam extraction window wherein vacuum needs to be maintained at a minimum 10-6 torr. Four sputter ion pumps are directly fixed on the cavity container to obtain maximum pumping efficiency. The fore vacuum is generated using a combination rotary and a roots pump. The beam extraction widow has a 50 and 956 m thick titanium foil acting as the exit window for electrons from the vacuum into air. Both the cavity and the beam extraction window are coupled through a gate valve which acts as a vacuum separator isolating the systems from each other during foil puncture, scanning system failure or any other related problems. This paper reports details of the vacuum system, measurements, vacuum leaks and detection and the operational experience related to maintenance and troubleshooting exercises that have been carried in the accelerator

  20. Emission sources in scanning electron microscopy

    International Nuclear Information System (INIS)

    Malkusch, W.

    1990-01-01

    Since the beginning of the commercial scanning electron microscopy, there are two kinds of emission sources generally used for generation of the electron beam. The first group covers the cathodes heated directly and indirectly (tungsten hair-needle cathodes and lanthanum hexaboride single crystals, LaB 6 cathode). The other group is the field emission cathodes. The advantages of the thermal sources are their low vacuum requirement and their high beam current which is necessary for the application of microanalysis units. Disadvantages are the short life and the low resolution. Advantages of the field emission cathode unambiguously are the possibilities of the very high resolution, especially in the case of low acceleration voltages. Disadvantages are the necessary ultra-high vacuum and the low beam current. An alternative source is the thermally induced ZrO/W field emission cathode which works stably as compared to the cold field emission and does not need periodic flashing for emitter tip cleaning. (orig.) [de

  1. The 1H(t,n)3He reaction as monoenergetic neutron source in the (10/20) MeV energy interval

    International Nuclear Information System (INIS)

    Zago, G.

    1981-01-01

    The 1 H(t,n) 3 He reaction, considered as a neutron source in the (10/20) MeV energy interval, is a ''white'' neutron source having intensity, mean energy, and directionality which may prove advantageous in technological and biomedical researches. (author)

  2. /sup 1/H(t,n)/sup 3/He reaction as monoenergetic neutron source in the (10/20) MeV energy interval

    Energy Technology Data Exchange (ETDEWEB)

    Zago, G. (Padua Univ. (Italy). Ist. di Fisica)

    1981-11-14

    The /sup 1/H(t,n)/sup 3/He reaction, considered as a neutron source in the (10/20) MeV energy interval, is a ''white'' neutron source having intensity, mean energy, and directionality which may prove advantageous in technological and biomedical researches.

  3. Resonant dissociation in N2 by electron impact: a source of heating in the thermosphere and auroras

    International Nuclear Information System (INIS)

    Spence, D.; Burrow, P.D.

    1979-01-01

    An electron impact resonant dissociation process, leading to superthermal atom production in molecular nitrogen is described. The maximum cross section for this process is found to be 2.5 x 10 -18 cm 2 at 10 eV. Measurements of scattered electrons indicate a value of -65 to -90 MeV for the electron affinity of N. The possible role of resonant dissociation as a source of heating in the thermosphere and in auroras is discussed

  4. Measurement of cross sections for the scattering of neutrons in the energy range from 2 MeV to 4 MeV with the 15N(p,n) reaction as neutron source

    International Nuclear Information System (INIS)

    Poenitz, Erik

    2010-01-01

    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 15 N(p,n) 15 O reaction was chosen, as it allows the production of monoenergetic neutrons with up to 5.7MeV energy. In this work, the 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 209 Bi and 181 Ta samples at 4 MeV incident neutron energy. Results are compared with other

  5. Reduction of dose enhancement from backscattered radiation at tissue-metal interfaces irradiated with 6MeV electrons

    International Nuclear Information System (INIS)

    Steel, B.

    1996-01-01

    Due to Electron Back Scatter (EBS), electron irradiation of tissue having under lying lead shielding results in an increase in dose to the tissue on the entrance side of the lead. In these situations dose increases as high as 80% have been reported in the literature. Saunders (British Journal of Radiology, 47, 467-470) noted that dose enhancement is dependent on atomic number of the under lying material approximately as Z 0.5 , and it increases at lower incident electron energies. In our clinic we use 2mm of lead shielding to protect under lying normal tissue when 6MeV electrons are used to treat lips and ears. The object of this study was to find the thinnest combination of materials to reduce the total dose to an acceptable level, with the provisos that; the patient does not come into contact with the lead or other metals, the finished shield could comfortabley be placed between the patient's lip and teeth, and that the materials are sufficietly malleable to work into custom shields. Various combinations of dental wax and aluminium were trialed. That which proved to give the best compromise between reduction of EBS and total shielding thickness was, 1mm of aluminim on the beam side of the lead with 1mm of dental wax to completely enclose the shield. In practice the manufactured shields are approximately 6 mm thick, and are usually not uncomfortable for the patient. (author)

  6. The radiation field measurement and analysis outside the shielding of A 10 MeV electron irradiation accelerator

    Science.gov (United States)

    Shang, Jing; Li, Juexin; Xu, Bing; Li, Yuxiong

    2011-10-01

    Electron accelerators are employed widely for diverse purposes in the irradiation-processing industry, from sterilizing medical products to treating gemstones. Because accelerators offer high efficiency, high power, and require little preventative maintenance, they are becoming more and more popular than using the 60Co isotope approach. However, the electron accelerator exposes potential radiation hazards. To protect workers and the public from exposure to radiation, the radiation field around the electronic accelerator must be assessed, especially that outside the shielding. Thus, we measured the radiation dose at different positions outside the shielding of a 10-MeV electron accelerator using a new data-acquisition unit named Mini-DDL (Mini-Digital Data Logging). The measurements accurately reflect the accelerator's radiation status. In this paper, we present our findings, results and compare them with our theoretical calculations. We conclude that the measurements taken outside the irradiation hall are consistent with the findings from our calculations, except in the maze outside the door of the accelerator room. We discuss the reason for this discrepancy.

  7. The radiation field measurement and analysis outside the shielding of A 10 MeV electron irradiation accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Shang Jing [National Synchrotron Radiation Lab, University of Science and Technology of China (China); Li Juexin, E-mail: juexin@ustc.edu.cn [National Synchrotron Radiation Lab, University of Science and Technology of China (China); Xu Bing; Li Yuxiong [National Synchrotron Radiation Lab, University of Science and Technology of China (China)

    2011-10-01

    Electron accelerators are employed widely for diverse purposes in the irradiation-processing industry, from sterilizing medical products to treating gemstones. Because accelerators offer high efficiency, high power, and require little preventative maintenance, they are becoming more and more popular than using the {sup 60}Co isotope approach. However, the electron accelerator exposes potential radiation hazards. To protect workers and the public from exposure to radiation, the radiation field around the electronic accelerator must be assessed, especially that outside the shielding. Thus, we measured the radiation dose at different positions outside the shielding of a 10-MeV electron accelerator using a new data-acquisition unit named Mini-DDL (Mini-Digital Data Logging). The measurements accurately reflect the accelerator's radiation status. In this paper, we present our findings, results and compare them with our theoretical calculations. We conclude that the measurements taken outside the irradiation hall are consistent with the findings from our calculations, except in the maze outside the door of the accelerator room. We discuss the reason for this discrepancy.

  8. Fibre optic control for electron gun power supplies and data acquisition of 3 MeV DC accelerator

    International Nuclear Information System (INIS)

    Chavan, R.B.; Yadav, Vivek; Dixit, K.P.; Bakhtsingh, R.I.; Rajan, Rehim; Nanu, K.; Mittal, K.C.; Chakravarthy, D.P.; Gantayet, L.M.

    2011-01-01

    A 3 MeV, 10 mA DC Industrial Electron Beam Accelerator is being commissioned at Electron Beam Centre, Navi Mumbai. The electron beam is generated by a triode electron gun and injected into the accelerating column at 5 keV. The gun and its power supplies, (5 kV anode, 3 kV grid and 15V/20A filament), are floating at 3 Million volts, and are situated in a tank which is pressurized with SF6 at 6 kg/cm 2 . These power supplies are required to be controlled remotely. The various accelerator parameters like Beam Energy, Beam Current, RF Electrode Voltage, Power Oscillator Plate Voltage / Current and Vacuum are required to be monitored during beam operation. The software was developed in VB.Net for control and data acquisition. The database is provided in SQL 2005 for storing the data. For this purpose, control system using ADAM modules and Optical fibre has been designed and developed. This paper describes the design features of the control system and experience of use of control software during initial beam trials. (author)

  9. Electron-lattice energy relaxation in laser-excited thin-film Au-insulator heterostructures studied by ultrafast MeV electron diffraction.

    Science.gov (United States)

    Sokolowski-Tinten, K; Shen, X; Zheng, Q; Chase, T; Coffee, R; Jerman, M; Li, R K; Ligges, M; Makasyuk, I; Mo, M; Reid, A H; Rethfeld, B; Vecchione, T; Weathersby, S P; Dürr, H A; Wang, X J

    2017-09-01

    We apply time-resolved MeV electron diffraction to study the electron-lattice energy relaxation in thin film Au-insulator heterostructures. Through precise measurements of the transient Debye-Waller-factor, the mean-square atomic displacement is directly determined, which allows to quantitatively follow the temporal evolution of the lattice temperature after short pulse laser excitation. Data obtained over an extended range of laser fluences reveal an increased relaxation rate when the film thickness is reduced or the Au-film is capped with an additional insulator top-layer. This behavior is attributed to a cross-interfacial coupling of excited electrons in the Au film to phonons in the adjacent insulator layer(s). Analysis of the data using the two-temperature-model taking explicitly into account the additional energy loss at the interface(s) allows to deduce the relative strength of the two relaxation channels.

  10. Neutron leakage from Pb and Bc spherical shells with 14 MeV central neutron source

    International Nuclear Information System (INIS)

    Antonov, S.; Daskalov, G.; Ilieva, K.; Jordanova, J.; Prodanova, R.; Zagryadskij, V.A.; Novikov, V.M.; Chuvilin, D.Yu.

    1988-01-01

    Results of measuring neutron leakage from spherical shells of different thickness, made of Pb and Be with a point neutron source in the sphere centrum are presented. The experiment results are compared to calculations according to different programs using data of various nuclear data libraies. The comparison has shown that all the calculations understate the neutron leakage from Pb assmebly. 9 refs.; 2 tabs

  11. Bunch-shape monitor for a picosecond single-bunch beam of a 35 MeV electron linear accelerator

    International Nuclear Information System (INIS)

    Hosono, Yoneichi; Nakazawa, Masaharu; Iguchi, Tetsuo

    1995-01-01

    A non-interactive-type bunch-shape and beam intensity monitor for a 35 MeV electron linear accelerator (linac) has been developed. The monitor consists of an electric SMA-type connector and an Al pipe of 50 mm inner diameter. Test measurements of the present monitor have been made under the conditions of the accelerated charges of lower than 27 nC/pulse and the pulse width ranging from 6 to 30 ps (Full Width at Half Maximum). The results show that the present monitor is applicable to bunch-shape measurement of the picosecond single-bunch beam. The monitor output is also found to be proportional to the beam intensity of more than 0.05 nC/pulse. (author)

  12. Fractionation study: survival of mouse intestinal crypts to exposure of 60Co and 11 MeV electrons

    International Nuclear Information System (INIS)

    Coffey, C.W.

    1975-01-01

    The study was conducted to determine a statistical procedure for the quantification of time, dose, fraction relations for mouse intestinal crypt survival after fractionated Co-60 and 11-MeV electron irradiation. In the initial phase of the investigation CDF/1 male mice were exposed to fractionated Co-60 irradiation. A completely randomized experimental design with three factors, total time from initiation to completion of fractionation schedule, number of fractions, and total dose was utilized. The experimental animals were irradiated with a Co-60 panoramic irradiator unit at an absorbed dose rate of approximately 51 rads per minute. Two days after completion of the fractionation schedule, the experimental animals were sacrificed by cervical dislocation. Sections of intestinal jejunum were resected and routine histological preparations performed. The surviving crypts were scored with a compound microscope using a quantitative counting technique. The resulting crypt survival was observed to increase for increasing total times and fraction numbers

  13. Effect of Ge, Sn, Sb on the resistance to swelling of austenitic alloys irradiated by 1 MeV electrons

    International Nuclear Information System (INIS)

    Dubuisson, P.; Levy, V.; Seran, J.L.

    1987-01-01

    The effect of new solute elements namely Ge, Sn and Sb on the void swelling resistance of austenitic alloys irradiated with 1 MeV electrons has been studied. Except for tin in Ti-modified 316, all solute improve the swelling resistance of base alloys. Tin addition shifts the swelling peak of 316 S.S. to high temperature. In fact, these solute additions have the same qualitative effect on the swelling components: they enhance the void density and decrease strongly void growth rate. This effect is opposite to the one of usual swelling inhibitors such as Si or Ti which decrease the void density. We have explained this influence on the void nucleation and void growth by introducing a strong interaction between vacancies and solute atoms in a void growth model

  14. Measurement of charge composition of electron flows with an energy above hundreds MeV in inner radiaion belt

    International Nuclear Information System (INIS)

    Gusev, A.A.; Pugacheva, G.I.

    1990-01-01

    A detector for studying the charge composition of a high-energy electron component of an internal radiation belt when measuring the precipitation of charged particles in the region of Brazil magnetic anomaly is suggested. The detector is a telescope consisting of two semiconductors and CsI crystal housed into a protection detector in the form of a cup made of plastic scintillator. An absorber of plastic scintillator is placed between semiconductive detections. The detector may record positrons with energy up to 5 MeV in the composition of precipitating particles from the belt in definite detector signal combination and specific energy release 511 keV in CsI crystal. 16 refs.; 3 figs

  15. Instrumental development of a quasi-relativistic ultrashort electron beam source for electron diffractions and spectroscopies.

    Science.gov (United States)

    Shin, Young-Min; Figora, Michael

    2017-10-01

    A stable femtosecond electron beam system has been configured for time-resolved pump-probe experiments. The ultrafast electron diffraction (UED) system is designed with a sub-MeV photoelectron beam source pulsed by a femtosecond UV laser and nondispersive beamline components, including a bunch compressor-a pulsed S-band klystron is installed and fully commissioned with 5.5 MW peak power in a 2.5 μs pulse length. A single-cell RF photo-gun is designed to produce 1.6-16 pC electron bunches in a photoemission mode with 150 fs pulse duration at 0.5-1 MeV. The measured RF system jitters are within 1% in magnitude and 0.2° in phase, which would induce 3.4 keV and 0.25 keV of ΔE, corresponding to 80 fs and 5 fs of Δt, respectively. Our particle-in-cell simulations indicate that the designed bunch compressor reduces the time-of-arrival jitter by about an order of magnitude. The transport and focusing optics of the designed beamline with the bunch compressor enables an energy spread within 10 -4 and a bunch length (electron probe) within quasi-relativistic UED system.

  16. 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.

  17. Dose distribution considerations of medium energy electron beams at extended source-to-surface distance

    International Nuclear Information System (INIS)

    Saw, Cheng B.; Ayyangar, Komanduri M.; Pawlicki, Todd; Korb, Leroy J.

    1995-01-01

    Purpose: To determine the effects of extended source-to-surface distance (SSD) on dose distributions for a range of medium energy electron beams and cone sizes. Methods and Materials: The depth-dose curves and isodose distributions of 6 MeV, 10 MeV, and 14 MeV electron beams from a dual photon and multielectron energies linear accelerator were studied. To examine the influence of cone size, the smallest and the largest cone sizes available were used. Measurements were carried out in a water phantom with the water surface set at three different SSDs from 101 to 116 cm. Results: In the region between the phantom surface and the depth of maximum dose, the depth-dose decreases as the SSD increases for all electron beam energies. The effects of extended SSD in the region beyond the depth of maximum dose are unobservable and, hence, considered minimal. Extended SSD effects are apparent for higher electron beam energy with small cone size causing the depth of maximum dose and the rapid dose fall-off region to shift deeper into the phantom. However, the change in the depth-dose curve is small. On the other hand, the rapid dose fall-off region is essentially unaltered when the large cone is used. The penumbra enlarges and electron beam flatness deteriorates with increasing SSD

  18. 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.

  19. Measurement of the neutron and gamma-ray spectra originating from a 14-MeV neutron source in liquid nitrogen and liquid air

    International Nuclear Information System (INIS)

    Broecker, B.; Clausen, K.; Schneider-Kuehnle, P.; Weinert, M.

    1975-01-01

    An experiment to measure the radiation transport originating from a 14-MeV neutron source in liquid nitrogen and liquid air is presented. Neutron and gamma-ray spectra were measured with a proton-recoil NE 213 scintillator and with four spherical proportional counters in a tank filled with liquid nitrogen or liquid air. The neutron spectra cover the energy range of 20 keV to 18 MeV. The source-detector separation varies in the liquid medium between 60 and 240 cm. The experimental setup is briefly described and the errors are estimated. (2 tables, 9 figures) (auth)

  20. Silicon nanowire based high brightness, pulsed relativistic electron source

    Directory of Open Access Journals (Sweden)

    Deep Sarkar

    2017-06-01

    Full Text Available We demonstrate that silicon nanowire arrays efficiently emit relativistic electron pulses under irradiation by a high-intensity, femtosecond, and near-infrared laser (∼1018 W/cm2, 25 fs, 800 nm. The nanowire array yields fluxes and charge per bunch that are 40 times higher than those emitted by an optically flat surface, in the energy range of 0.2–0.5 MeV. The flux and charge yields for the nanowires are observed to be directional in nature unlike that for planar silicon. Particle-in-cell simulations establish that such large emission is caused by the enhancement of the local electric fields around a nanowire, which consequently leads to an enhanced absorption of laser energy. We show that the high-intensity contrast (ratio of picosecond pedestal to femtosecond peak of the laser pulse (10−9 is crucial to this large yield. We extend the notion of surface local-field enhancement, normally invoked in low-order nonlinear optical processes like second harmonic generation, optical limiting, etc., to ultrahigh laser intensities. These electron pulses, expectedly femtosecond in duration, have potential application in imaging, material modification, ultrafast dynamics, terahertz generation, and fast ion sources.

  1. Radiation damage in uranium under electron irradiation of energies up to 20 MeV

    International Nuclear Information System (INIS)

    Emets, N.L.; Zelenskij, V.F.; Kuz'menko, V.A.; Ranyuk, Yu.N.; Reznichenko, Eh.A.; Shilyaev, B.A.; Yamnitskij, V.A.

    1980-01-01

    The problem of conservation of primary radiation-induced defects in uranium irradiated by electrons with the energy exceeding photo fission threshold is considered. Calculation of uranium burnout is carried out. Calculations are conducted by the method of mathematical simulation, using some nuclear models; development of electromagnetic cascade in uranium, photofission process, elastic and inelastic electron scattering, as well as some secondary processes are taken into account. Proved is the fact of anomalous growth of uranium under electron irradiation, registered earlier experimentally. It is shown, that in case of acquiring the value Ed=15 eV radiation uranium growth at low levels of burnout can be explained by the complete capture of all the primary radiationn-induced defects into dislocation loops [ru

  2. Revealing by secondary electronic emission of internal electric fields in the yttriated zirconia, irradiated by electrons of 1 MeV

    International Nuclear Information System (INIS)

    Blaise, G.; Paris-11 Univ., 91 - Orsay

    2007-01-01

    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 IC produced by the charges trapping in the material and the current I SB due to secondary and backscattered electrons which come from the sample. The Secondary Emission coefficient is given by σ=I SB /(I SB +I IC ). The charges trapping during an electrons injection leads to a variation of σ for its intrinsic value σ 0 relative to the uncharged material, until the stationary value σ 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 σ of a fresh yttriated zirconia and of an yttriated zirconia irradiated by electrons of 1 MeV with a dose rate of 10 18 e/cm 2 , it has been revealed that an internal field (due to irradiation) of about 0.5*10 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 + 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 + 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 irradiation with electrons of 1 MeV. (O.M.)

  3. The Polarized Electron Source at ELSA

    International Nuclear Information System (INIS)

    Drachenfels, Wolther von; Frommberger, Frank; Gowin, Michael; Hillert, Wolfgang; Hoffmann, Markus; Neff, Bernhold

    2003-01-01

    At the electron stretcher accelerator ELSA in Bonn a pulsed 50 kV inverted gun of polarized electrons has been in operation since February 2000. A strained-layer superlattice crystal is used to deliver a beam with a polarization of about 80 %. A flashlamp-pumped Ti-Sapphire laser with a pulse repetition rate of 50 Hz serves as source of light. The gun is operated in space charge limitation. The current can be chosen by varying the distance between cathode and anode. With 1 μs pulses of 100 mA the source was particularly used together with a polarized target for a GDH sum rule experiment. The high photocathode lifetime allows continuous operation at 100 mA typically for periods of about two weeks without maintenance. So far no change of the crystal was necessary

  4. Dose-response relationship for chromosomal aberrations induced in human lymphocytes by 18 MeV electron beam irradiation

    International Nuclear Information System (INIS)

    Lashin, E.A.; Elaasar, E.M.; Moustafa, H.F.; Bakir, Y.Y.; Al Zenki, S.D.

    1990-01-01

    Dose response curves for lymphocyte chromosome aberration frequencies using X- and gamma radiation became an important and reliable indicator as biological dosimeter especially in radiation accidents and occupational over exposures. Nowadays electron beam therapy is frequently used for their advantages in cases of tumours under or near to the body surface. Dose-response curves for these electron beams are rarely published. Human peripheral blood lymphocytes were in vitro irradiated with various low and high doses (0.1 Gy to 4.9 Gy) of 18 MeV electron beams to utilize such a dose-response curve using chromosomal aberration frequencies as a biological indicator. Then we compared the biological curve with physically obtained curves normally used in planning for radiotherapy treatment. It is interesting to find a significant difference between both of them. The biological curve is generally higher in value and the aberrations induced by 93% of a dose is significantly higher and deeper in site than those aberrations induced by the 100% dose calculated physically. If the above observation is confirmed by detailed studies, it would be of importance to the radiotherapist to plan for isodose curves according to biological determinations. (author)

  5. Radiation damage measurements on nonmetals made during irradiation with 1 to 3 MeV electrons. Final Report

    International Nuclear Information System (INIS)

    Levy, P.W.

    1982-01-01

    To investigate the fundamental processes producing radiation damage in nonmetals a unique facility has been developed for making optical absorption, luminescence and other measurements during irradiation with 1 to 3 MeV electrons. Measurements are made with a 13 meter long double beam spectrometer arranged so that all sensitive components, e.g., phototubes, are outside of the irradiation chamber. A computer provdies automatic control and data recording. A 256 point absorption and a 256 point luminescence spectra are recorded as often as every 40 seconds in either the 200-400 or 400-800 mm wavelength range. Samples are irradiated, at temperatures between 20 and 900 C, in an electronically controlled chamber containing He exchange gas and equipped with thin Havar windows to transmit the electron beam and high purity fused silica windows for the spectrophotometer beams. Radiation induced luminescence and absorption in the chamber windows, etc. is eliminated by the double beam spectrophotometer. Studies made with this equipment demonstrate clearly that many of the processes occurring during damage formation are transient

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

    International Nuclear Information System (INIS)

    Wang Qingyan; Zhang Zhonghua; Geng Hongbin; Sun Chengyue; Yang Dezhuang; He Shiyu; Hu Zhaochu

    2012-01-01

    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 × 10 16 cm −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.

  7. Microwave and RF vacuum electronic power sources

    CERN Document Server

    Carter, Richard G

    2018-01-01

    Do you design and build vacuum electron devices, or work with the systems that use them? Quickly develop a solid understanding of how these devices work with this authoritative guide, written by an author with over fifty years of experience in the field. Rigorous in its approach, it focuses on the theory and design of commercially significant types of gridded, linear-beam, crossed-field and fast-wave tubes. Essential components such as waveguides, resonators, slow-wave structures, electron guns, beams, magnets and collectors are also covered, as well as the integration and reliable operation of devices in microwave and RF systems. Complex mathematical analysis is kept to a minimum, and Mathcad worksheets supporting the book online aid understanding of key concepts and connect the theory with practice. Including coverage of primary sources and current research trends, this is essential reading for researchers, practitioners and graduate students working on vacuum electron devices.

  8. Facility to disinfect medical wastes by 10 MeV electron beam

    International Nuclear Information System (INIS)

    Kerluke, D.R.

    1998-01-01

    As regulations related to the disposal of infectious hospital and other medical waste are become increasingly stringent, hospitals and governments worldwide are looking to develop more effective and economical means to disinfect such waste materials prior to them being ultimately landfilled, incinerated or recycled. With the advent of reliable high-energy, high-power industrial electron accelerators, the prospect now exists to centralize collection of much of the infectious medical waste for major metropolitan areas at a single facility, and render it harmless using irradiation. Using much of the same or similar methodologies already developed for single-use medical device sterilization and for bioburden reduction in other goods, high energy electron beam treatment offers unique process advantages which become increasingly attractive with the economies of scale available at higher power. This paper will explore some of the key issues related to the safe disposition of infectious hospital and other medical waste, related irradiation research projects, and the design and economic factors related to an electron beam facility dedicated to this application. This will be presented in the context of the Rhodotron family of electron beam accelerators manufactured by Ion Beam Applications s.a. (author)

  9. Study of LiF:Mg,Ti and CaSO4:Dy dosimeters TL response to electron beams of 6 MeV applied to radiotherapy using PMMA and solid water phantoms

    International Nuclear Information System (INIS)

    Bravim, A.; Sakuraba, R.K.; Cruz, J.C.; Campos, L.L.

    2011-01-01

    The performance of CaSO 4 :Dy and LiF:Mg,Ti dosimeters to electron beams applied to radiotherapy was investigated. The TL response of these dosimeters was studied for 6 MeV electron beams using PMMA and Solid Water (SW) phantoms. The dosimeters were previously separated in groups according to their TL individual sensitivities to 60 Co gamma-radiation in air under electronic equilibrium conditions. After that, they were irradiated with 6 MeV electron doses of 0.1, 0.5, 1, 5 and 10 Gy using a linear accelerator Clinac 2100C Varian of Hospital Israelita Albert Einstein – HIAE. The electron beam irradiations were performed using a 10 × 10 cm 2 field size, 100 cm source-phantom surface distance and the dosimeters were positioned at the depth of maximum dose (1.2 cm). The TL readings were carried out between 24 and 32 h after irradiation using a Harshaw 3500 TL reader. The TL dose–response of both type of dosimeters and phantoms presented linear behavior on the electron dose range from 0.1 to 5 Gy CaSO 4 :Dy dosimeter is 21 times more sensitive than LiF:Mg,Ti, dosimeter commonly used in clinical dosimetry. The obtained results indicate that the performance of CaSO 4 :Dy dosimeters is similar to LiF:Mg,Ti dosimeters and this material can be an alternative dosimetric material to be used to clinical electron beams dosimetry.

  10. Pulsed magnet for commutation of 15 MeV electron bunches

    International Nuclear Information System (INIS)

    Zav'yalov, V.V.; Semenov, V.K.

    1987-01-01

    The ironless magnet, which extracts certain current pulses from the pulsed microtron electron beam, is described. The 1.4 kGs working field is created in the 12 mm gap between two plane coils arranged inside a vacuum chamber. A simple generator of sinusoidal pulses with the 300 A amplitude and 66 μs duration is used for coil power supply. The power consumption is 660 W at the 400 Hz pulse repetition frequency

  11. Effect of 1.5 MeV electron irradiation on β-Ga2O3 carrier lifetime and diffusion length

    Science.gov (United States)

    Lee, Jonathan; Flitsiyan, Elena; Chernyak, Leonid; Yang, Jiancheng; Ren, Fan; Pearton, Stephen J.; Meyler, Boris; Salzman, Y. Joseph

    2018-02-01

    The influence of 1.5 MeV electron irradiation on minority transport properties of Si doped β-Ga2O3 vertical Schottky rectifiers was observed for fluences up to 1.43 × 1016 cm-2. The Electron Beam-Induced Current technique was used to determine the minority hole diffusion length as a function of temperature for each irradiation dose. This revealed activation energies related to shallow donors at 40.9 meV and radiation-induced defects with energies at 18.1 and 13.6 meV. Time-resolved cathodoluminescence measurements showed an ultrafast 210 ps decay lifetime and reduction in carrier lifetime with increased irradiation.

  12. A water-cooled target of a 14 MeV neutron source

    International Nuclear Information System (INIS)

    Ogawa, Masuro; Seki, Masahiro; Kawamura, Hiroshi; Sanokawa, Konomo

    1979-09-01

    For the cooling system of a stationary target for the fusion neutronics source (FNS), designed to meet the structural, thermal and hydraulic requirements, thermohydraulic experiments were made. In the heat transfer experiment, in place of an accelerator, electric-heater assemblies were used. The relation of head loss and heat transfer was obtained as a function of Reynolds number. The head loss was not large for flow rates up to 1.3 l/s. Neither vibration of the apparatus nor cavitation of water was observed even at the maximum flow rate. The heat load of 1 kW for the beam diameter of 15mm, i.e. the requirement of FNS, could be removed by 0.2 l/s water flow, with the target-surface maximum temperature kept below 200 0 C. Extrapolation of the experimental results showed that with the target system, the maximum heat load is 2.3 kW for the beam of diameter 15 mm. The value is sufficiently large compared with the heat load of FNS; with finned cooling surfaces, the heat loads up to 3.7 kW may be removed. (author)

  13. Formation of 1.4 MeV runaway electron flows in air using a solid-state generator with 10 MV/ns voltage rise rate

    Science.gov (United States)

    Mesyats, G. A.; Pedos, M. S.; Rukin, S. N.; Rostov, V. V.; Romanchenko, I. V.; Sadykova, A. G.; Sharypov, K. A.; Shpak, V. G.; Shunailov, S. A.; Ul'masculov, M. R.; Yalandin, M. I.

    2018-04-01

    Fulfillment of the condition that the voltage rise time across an air gap is comparable with the time of electron acceleration from a cathode to an anode allows a flow of runaway electrons (REs) to be formed with relativistic energies approaching that determined by the amplitude of the voltage pulse. In the experiment described here, an RE energy of 1.4 MeV was observed by applying a negative travelling voltage pulse of 860-kV with a maximum rise rate of 10 MV/ns and a rise time of 100-ps. The voltage pulse amplitude was doubled at the cathode of the 2-cm-long air gap due to the delay of conventional pulsed breakdown. The above-mentioned record-breaking voltage pulse of ˜120 ps duration with a peak power of 15 GW was produced by an all-solid-state pulsed power source utilising pulse compression/sharpening in a multistage gyromagnetic nonlinear transmission line.

  14. Competition Between Radial Loss and EMIC Wave Scattering of MeV Electrons During Strong CME-shock Driven Storms

    Science.gov (United States)

    Hudson, M. K.; Jaynes, A. N.; Li, Z.; Malaspina, D.; Millan, R. M.; Patel, M.; Qin, M.; Shen, X.; Wiltberger, M. J.

    2017-12-01

    The two strongest storms of Solar Cycle 24, 17 March and 22 June 2015, provide a contrast between magnetospheric response to CME-shocks at equinox and solstice. The 17 March CME-shock initiated storm produced a stronger ring current response with Dst = - 223 nT, while the 22 June CME-shock initiated storm reached a minimum Dst = - 204 nT. The Van Allen Probes ECT instrument measured a dropout in flux for both events which can be characterized by magnetopause loss at higher L values prior to strong recovery1. However, rapid loss is seen at L 3 for the June storm at high energies with maximum drop in the 5.2 MeV channel of the REPT instrument coincident with the observation of EMIC waves in the H+ band by the EMFISIS wave instrument. The rapid time scale of loss can be determined from the 65 minute delay in passage of the Probe A relative to the Probe B spacecraft. The distinct behavior of lower energy electrons at higher L values has been modeled with MHD-test particle simulations, while the rapid loss of higher energy electrons is examined in terms of the minimum resonant energy criterion for EMIC wave scattering, and compared with the timescale for loss due to EMIC wave scattering which has been modeled for other storm events.2 1Baker, D. N., et al. (2016), Highly relativistic radiation belt electron acceleration, transport, and loss: Large solar storm events of March and June 2015, J. Geophys. Res. Space Physics, 121, 6647-6660, doi:10.1002/2016JA022502. 2Li, Z., et al. (2014), Investigation of EMIC wave scattering as the cause for the BARREL 17 January 2013 relativistic electron precipitation event: A quantitative comparison of simulation with observations, Geophys. Res. Lett., 41, 8722-8729, doi:10.1002/2014GL062273.

  15. Alanine-EPR dosimetry in 10 MeV electron beam to optimize process parameters for food irradiation

    International Nuclear Information System (INIS)

    Sanyal, B.; Kumar, S.; Kumar, M.; Mittal, K.C.; Sharma, A.

    2011-01-01

    Absorbed dose in a food product is determined and controlled by several components of the LINAC irradiation facility as well as the product. Standardization of the parameters characterizing the facility components, process load and the irradiation conditions collectively termed as 'process parameters' are of paramount importance for successful dose delivery to the food products. In the present study alanine-EPR dosimetry system was employed to optimize the process parameters of 10 MeV electron beam of a LINAC facility for commercial irradiation of food. Three sets of experiments were carried out with different food commodities namely, mango, potato and rawa with the available product conveying system of different irradiation geometry like one sided or both sided mode of irradiation. Three dimensional dose distributions into the process load for low dose requiring food commodities (0.25 to 1 kGy) were measured in each experiment. The actual depth dose profile in food product and useful scan width of the electron beam were found out to be satisfactory for commercial radiation processing of food. Finally a scaled up experiment with commercial food product (packets of Rawa) exhibited adequate dose uniformity ratio of 3 proving the feasibility of the facility for large scale radiation processing of food commodities. (author)

  16. Electrical behaviour of butyl acrylate/methyl methacrylate copolymer films irradiated with 1.5 MeV electron beam

    Energy Technology Data Exchange (ETDEWEB)

    Radwan, R.M. [Radiation Physics Department, National Center for Radiation Research and Technology (NCRRT), Atomic Energy Authority (AEA), P. O. Box 29, Nasr City, Cairo (Egypt)], E-mail: redaradwan_2000@yahoo.com; Fawzy, Y.H.A. [Radiation Physics Department, National Center for Radiation Research and Technology (NCRRT), Atomic Energy Authority (AEA), P. O. Box 29, Nasr City, Cairo (Egypt); El-Hag Ali, A. [Polymer Chemistry Department, National Center for Radiation Research and Technology (NCRRT), Atomic Energy Authority (AEA), P. O. Box 29, Nasr City, Cairo (Egypt)

    2008-02-15

    Electrical conductivity and dielectric parameters of the (BuA/MMA) copolymer films irradiated with 1.5 MeV electron beam (EB) have been studied. The samples were irradiated with different doses of the electron beam: 5, 10, 50, 125 and 200 kGy. The electrical conductivity of the samples was found to decrease as the irradiation dose increases. The temperature dependence of the direct current (dc) conductivity for unirradiated and irradiated samples has been obtained over a temperature range from 293 to 373 K. The activation energy values were calculated for all samples. Moreover, measurements of the dielectric constant, dielectric loss and alternating current (ac) conductivity were performed at a frequency range from 100 Hz to 5 MHz at room temperature. The results indicated that the EB irradiation has formed some traps in the energy gap, which reduce the movement of the charge carriers. Furthermore, a direct proportional relationship between the activation energy and the irradiation dose was estimated in two regions: below and above the glass transition temperature of the polymer. Dipole relaxation was observed in the samples, and the dose effect was found to shift this relaxation towards higher frequencies.

  17. Novel digital K-edge imaging system with transition radiation from an 855-MeV electron beam

    CERN Document Server

    Hagenbuck, F; Clawiter, N; Euteneuer, H; Görgen, F; Holl, P; Johann, K; Kiser, K H; Kemmer, J; Kerschner, T; Kettig, O; Koch, H; Kube, G; Lauth, W; Mauhay, H; Schütrumpf, M; Stotter, R; Strüder, L; Walcher, T; Wilms, A; von Zanthier, C; Zemter, M

    2001-01-01

    A novel K-edge imaging method has been developed at the Mainz Microtron MAMI aiming at a very efficient use of the transition radiation (TR) flux generated by the external 855-MeV electron beam in a foil stack. A fan-like quasi-monochromatic hard X-ray beam is produced from the +or-1-mrad-wide TR cone with a highly oriented pyrolytic graphite (HOPG) crystal. The absorption of the object in front of a 30 mm*10 mm pn charge-coupled device (pn-CCD) photon detector is measured at every pixel by a broad-band energy scan around the K-absorption edge. This is accomplished by a synchronous variation of the lateral crystal position and the electron beam direction which defines also the direction of the TR cone. The system has been checked with a phantom consisting of a 2.5- mu m thick molybdenum sample embedded in a 136- or 272- mu m-thick copper bulk foil. A numerical analysis of the energy spectrum for every pixel demonstrates that data as far as +or-0.75 keV away from the K edge of molybdenum at 20 keV still improv...

  18. Thermoluminescence spectra of natural CaF2 irradiated by 10MeV electrons

    International Nuclear Information System (INIS)

    Manrique, J.; Angulo, S.; Pardo, M.P.; Gastesi, R.; De la Cruz, A.; Perez, A.

    2006-01-01

    The spectra of thermoluminescence from natural and electron-irradiated fluorite in the 350-800nm spectral range were studied between room temperature and 500 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 o C. Main emissions occurred at 475, 575, 650 and 745nm, attributed to the Dy +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 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 19 and 2.7x10 19 s -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

  19. Angular distributions of absorbed dose of Bremsstrahlung and secondary electrons induced by 18-, 28- and 38-MeV electron beams in thick targets.

    Science.gov (United States)

    Takada, Masashi; Kosako, Kazuaki; Oishi, Koji; Nakamura, Takashi; Sato, Kouichi; Kamiyama, Takashi; Kiyanagi, Yoshiaki

    2013-03-01

    Angular distributions of absorbed dose of Bremsstrahlung photons and secondary electrons at a wide range of emission angles from 0 to 135°, were experimentally obtained using an ion chamber with a 0.6 cm(3) air volume covered with or without a build-up cap. The Bremsstrahlung photons and electrons were produced by 18-, 28- and 38-MeV electron beams bombarding tungsten, copper, aluminium and carbon targets. The absorbed doses were also calculated from simulated photon and electron energy spectra by multiplying simulated response functions of the ion chambers, simulated with the MCNPX code. Calculated-to-experimental (C/E) dose ratios obtained are from 0.70 to 1.57 for high-Z targets of W and Cu, from 15 to 135° and the C/E range from 0.6 to 1.4 at 0°; however, the values of C/E for low-Z targets of Al and C are from 0.5 to 1.8 from 0 to 135°. Angular distributions at the forward angles decrease with increasing angles; on the other hand, the angular distributions at the backward angles depend on the target species. The dependences of absorbed doses on electron energy and target thickness were compared between the measured and simulated results. The attenuation profiles of absorbed doses of Bremsstrahlung beams at 0, 30 and 135° were also measured.

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

    International Nuclear Information System (INIS)

    Paredes G, L.C.

    2001-01-01

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

  1. The use of a diode matrix in commissioning activities for electron energies ≥9 MeV: A feasibility study

    International Nuclear Information System (INIS)

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

    2009-01-01

    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 γ≤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 trade mark sign can play a useful role in

  2. SLC polarized beam source electron optics design

    International Nuclear Information System (INIS)

    Eppley, K.R.; Lavine, T.L.; Early, R.A.; Herrmannsfeldt, W.B.; Miller, R.H.; Schultz, D.C.; Spencer, C.M.; Yeremian, A.D.

    1991-05-01

    This paper describes the design of the beam-line from the polarized electron gun to the linac injector in the Stanford Linear Collider (SLC). The polarized electron source is a GaAs photocathode, requiring 10 -11 -Torr-range pressure for adequate quantum efficiency and longevity. The photocathode is illuminated by 3-nsec-long laser pulses. The quality of the optics for the 160-kV beam is crucial since electron-stimulated gas desorption from beam loss in excess of 0.1% of the 20-nC pulses may poison the photocathode. Our design for the transport line consists of a differential pumping region isolated by a pair of valves. Focusing is provided by a pair of Helmholtz coils and by several iron-encased solenoidal lenses. Our optics design is based on beam transport simulations using 2 1/2-D particle-in-cell codes to model the gun and to solve the fully-relativistic time-dependent equations of motion in three dimensions for electrons in the presence of azimuthally symmetric electromagnetic fields. 6 refs., 6 figs

  3. Observations of MeV electrons and scattered light from intense, subpicosecond laser-plasma interactions

    International Nuclear Information System (INIS)

    Darrow, C.; Lane, S.; Klem, D.; Perry, M.D.

    1993-01-01

    In this paper the authors present work in progress in their experimental investigation of the coupling of intense, subpicosecond laser pulses with plasmas preformed on solid targets. (This situation is to be contrasted with the interaction of intense laser fields with solid-density matter. A subject which has generated considerable interest in the last several years.) The characterization of the energy distribution of energetic electrons which escape a solid target irradiated by an intense laser is discussed. The authors have also performed experiments to study the excitation of parametric instabilities near the quarter-critical layer and second-harmonic generation near the critical layer in the plasma. They discuss some preliminary scattered light spectroscopy measurements

  4. Radiation processing of inhomogeneous objects at the 300 MeV electron linear accelerator

    International Nuclear Information System (INIS)

    Demeshko, O.A.; Kochetov, S.S.; Makhnenko, L.A.; Melnitsky, I.V.; Shopen, O.A.

    2009-01-01

    Comparison is made between the calculated and experimental doses absorbed by complex density-inhomogeneous objects during their radiation processing. The process of fast electron passage through the object and depth dose formation has been simulated by the Monte Carlo technique with the use of the licensed program package PENELOPE. The calculated and experimental data are found to be in good agreement (∼ 30 %). Preliminary simulation of the process of object irradiation at given conditions provides the necessary information when developing the methods for a particular group of objects. This is of particular importance at performing bilateral irradiation, when an insignificant density variance of different objects may lead to appreciable errors of dose determination in the symmetry plane of the object.

  5. Construction and operation of a 10 MeV electron accelerator and associated experimental facilities at Brookhaven National Laboratory, Upton, New York. Environmental assessment

    International Nuclear Information System (INIS)

    1994-02-01

    The purpose of this environmental impact statement is to determine whether there would be significant environmental impacts associated with the construction of an experimental facility at Brookhaven National Laboratory for radiation chemistry research and operation of the 10-MeV electron accelerator proposed for it. The document describes the need for action, alternative actions, the affected environment, and potential environmental impacts

  6. Film dosimetric investigations on the exposure of the eyes in radiation therapy of the head and the cervical region with fast electrons up to 17 MeV

    International Nuclear Information System (INIS)

    Stecher, M.; Eichler, R.

    1978-01-01

    Dose distributions in irradiating tumors of the head and the cervical region with 17 MeV electrons were determined in a phantom with films. From the isodoses obtained it can be derived how radiation reaches the eyes and how the dose to the eyes is influenced. Guidance is provided for the reduction of the dose to the eye. (author)

  7. Considerations for high-brightness electron sources

    International Nuclear Information System (INIS)

    Jameson, R.A.

    1990-01-01

    Particle accelerators are now used in many areas of physics research and in industrial and medical applications. New uses are being studied to address major societal needs in energy production, materials research, generation of intense beams of radiation at optical and suboptical wavelengths, treatment of various kinds of waste, and so on. Many of these modern applications require a high intensity beam at the desired energy, along with a very good beam quality in terms of the beam confinement, aiming, or focusing. Considerations for ion and electron accelerators are often different, but there are also many commonalties, and in fact, techniques derived for one should perhaps more often be considered for the other as well. We discuss some aspects of high-brightness electron sources here from that point of view. 6 refs

  8. 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.

  9. Average stopping powers for electron and photon sources for radiobiological modeling and microdosimetric applications

    Science.gov (United States)

    Vassiliev, Oleg N.; Kry, Stephen F.; Grosshans, David R.; Mohan, Radhe

    2018-03-01

    This study concerns calculation of the average electronic stopping power for photon and electron sources. It addresses two problems that have not yet been fully resolved. The first is defining the electron spectrum used for averaging in a way that is most suitable for radiobiological modeling. We define it as the spectrum of electrons entering the sensitive to radiation volume (SV) within the cell nucleus, at the moment they enter the SV. For this spectrum we derive a formula that combines linearly the fluence spectrum and the source spectrum. The latter is the distribution of initial energies of electrons produced by a source. Previous studies used either the fluence or source spectra, but not both, thereby neglecting a part of the complete spectrum. Our derived formula reduces to these two prior methods in the case of high and low energy sources, respectively. The second problem is extending electron spectra to low energies. Previous studies used an energy cut-off on the order of 1 keV. However, as we show, even for high energy sources, such as 60Co, electrons with energies below 1 keV contribute about 30% to the dose. In this study all the spectra were calculated with Geant4-DNA code and a cut-off energy of only 11 eV. We present formulas for calculating frequency- and dose-average stopping powers, numerical results for several important electron and photon sources, and tables with all the data needed to use our formulas for arbitrary electron and photon sources producing electrons with initial energies up to  ∼1 MeV.

  10. High-Current Plasma Electron Sources

    International Nuclear Information System (INIS)

    Gushenets, J.Z.; Krokhmal, V.A.; Krasik, Ya. E.; Felsteiner, J.; Gushenets, V.

    2002-01-01

    In this report we present the design, electrical schemes and preliminary results of a test of 4 different electron plasma cathodes operating under Kg h-voltage pulses in a vacuum diode. The first plasma cathode consists of 6 azimuthally symmetrically distributed arc guns and a hollow anode having an output window covered by a metal grid. Plasma formation is initiated by a surface discharge over a ceramic washer placed between a W-made cathode and an intermediate electrode. Further plasma expansion leads to a redistribution of the discharge between the W-cathode and the hollow anode. An accelerating pulse applied between the output anode grid and the collector extracts electrons from this plasma. The operation of another plasma cathode design is based on Penning discharge for preliminary plasma formation. The main glow discharge occurs between an intermediate electrode of the Penning gun and the hollow anode. To keep the background pressure in the accelerating gap at P S 2.5x10 4 Torr either differential pumping or a pulsed gas puff valve were used. The operation of the latter electron plasma source is based on a hollow cathode discharge. To achieve a sharp pressure gradient between the cathode cavity and the accelerating gap a pulsed gas puff valve was used. A specially designed ferroelectric plasma cathode initiated plasma formation inside the hollow cathode. This type of the hollow cathode discharge ignition allowed to achieve a discharge current of 1.2 kA at a background pressure of 2x10 4 Torr. All these cathodes were developed and initially tested inside a planar diode with a background pressure S 2x10 4 Torr under the same conditions: accelerating voltage 180 - 300 kV, pulse duration 200 - 400 ns, electron beam current - 1 - 1.5 kA, and cross-sectional area of the extracted electron beam 113 cm 2

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

    International Nuclear Information System (INIS)

    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

  12. Charged particle equilibrium corrections for photon sources from 400 keV to 1.4 MeV

    Science.gov (United States)

    Vasudevan, Latha

    Lack of charged particle equilibrium (CPE) has practical importance in radiological health protection, in nuclear medicine, and radiobiology where small radioactive point sources irradiate the human body accidentally or may be introduced into the body for diagnostic, therapeutic, or analytical purposes. The absorbed dose under CPE is readily calculated from knowledge of the photon energy fluence and mass-absorption coefficient of the material. When estimating absorbed dose rates at points close to the source, the primary radiation field varies appreciably over the region within the range of secondary particles. Under such conditions, CPE does not exist and prediction of absorbed dose becomes difficult. However, if one applies correction factors for non-CPE conditions, absorbed dose rates can be calculated fairly easily. In this dissertation, a CPE model was developed for non-CPE conditions to predict the fraction of charged particle equilibrium (GammaCPE) attained in a water medium for point sources of energies in the range from 400 keV to 1.4 MeV using EGS4-DOSRZ Monte Carlo calculation. A new methodology to calculate absorbed dose and kerma along the central axis of the cylindrical phantom was presented and the results were found to be in excellent agreement with published values. In order to corroborate with the EGS4-DOSRZ calculation, another model based on the Klein-Nishina single scattering cross section was developed to quantify the GammaCPE attained in water for point sources. A CPE path length coefficient (mu cm-1) was found for each photon energy and compared with published values. This coefficient was used to determine dose rates averaged over 1 cm2 at depths that are of interest in skin dose exposures. Experimental measurements of CPE were carried out for a Co-60 point source using GAFCHROMICRTM MD-55 film (1990) as the dosimetry media. The films were read using a document scanner. Dose rates obtained using the scanner method were compared with those

  13. Calculation of neutron and gamma-ray energy spectra in liquid air and liquid nitrogen due to 14-MeV neutron and californium-252 sources

    International Nuclear Information System (INIS)

    Straker, E.A.; Gritzner, M.L.; Harris, L. Jr.

    1978-01-01

    Calculations of neutron and gamma-ray fluences from 14-MeV neutron and 252 Cf sources in liquid air and liquid nitrogen have been performed. These calculations were made specifically for comparison with experimental data measured at Stohl, Federal Republic of Germany. The discrete-ordinates method was utilized with neutron and gamma-ray cross sections from ENDF/B-IV. One-dimensional calculational models were developed for the sources and tank. Limited comparisons are made with experimental data

  14. An electromagnetically focused electron beam line source

    International Nuclear Information System (INIS)

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

    2003-01-01

    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 deg., with cathode to work site distance of 130 mm. Dimensions of the beam (1.25x120 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

  15. Measurement of secondary gamma-ray skyshine and groundshine from intense 14 MeV neutron source facility

    Energy Technology Data Exchange (ETDEWEB)

    Yoshida, Shigeo; Morotomi, Ryutaro; Kondo, Tetsuo; Murata, Isao; Takahashi, Akito [Osaka Univ., Suita (Japan). Dept. of Nuclear Engineering

    2000-03-01

    Secondary gamma-ray skyshine and groundshine, including the direct contribution from the facility building, have been measured with an Hp-Ge detector and an NaI(Tl) detector at the Intense 14 MeV Neutron Source Facility OKTAVIAN of Osaka University, Japan. The mechanism of secondary gamma-rays propagation were analyzed with the measured spectrum with the Hp-Ge detector. The contribution of the skyshine was shown to be a continuum spectrum that was composed of mainly Compton scattered high energy secondary gamma-rays generated in the facility building created by (n, {gamma}) reaction. The contribution of the groundshine considerably contained secondary gamma-rays generated by {sup nat}Si (n, {gamma}) reaction in soil, including the albedo contribution from the ground. And the total contribution contained capture gamma-rays from iron (Fe) and other nuclides. The measurements with the NaI(Tl) detector as well as the Hp-Ge detector were carried out to investigate the dependence of gamma-ray dose as a function of distance from the neutron source up to hundreds meters. Consequently, it was found that the dependence could be fitted with the function of const.{center_dot}exp(-r/{lambda})/r{sup n}, where n values were around 2 except for the skyshine (n {approx} 1). It was thus indicated that the contribution of the skyshine could be propagated farther downfield than the direct contribution from the facility. The measured ratios of the three contributions (skyshine, groundshine, and direct contributions) and the distance dependence in each path were shown to be in good agreement with calculated results by the Monte Carlo transport code MCNP-4A. And the total contributions for the two detectors of NaI(Tl) and Hp-Ge agree excellently with each other. (author)

  16. Physics of high intensity nanosecond electron source

    International Nuclear Information System (INIS)

    Herrera-Gomez, A.; Spicer, W.E.

    1993-08-01

    A new high-intensity, short-time electron source is now being used at the Stanford Linear Accelerator Center (SLAC). Using a GaAs negative affinity semiconductor in the construction of the cathode, it is possible to fulfill operation requirements such as peak currents of tens of amperes, peak widths of the order of nanoseconds, hundreds of hours of operation stability, and electron spin polarization. The cathode is illuminated with high intensity laser pulses, and photoemitted electrons constitute the yield. Because of the high currents, some nonlinear effects are present. Very noticeable is the so-called Charge Limit (CL) effect, which consists of a limit on the total charge in each pulse-that is, the total bunch charge stops increasing as the light pulse total energy increases. In this paper, we explain the mechanism of the CL and how it is caused by the photovoltaic effect. Our treatment is based on the Three-Step model of photoemission. We relate the CL to the characteristics of the surface and bulk of the semiconductor, such as doping, band bending, surface vacuum level, and density of surface states. We also discuss possible ways to prevent the Char's Level effect

  17. Production and aging of paramagnetic point defects in P-doped floating zone silicon irradiated with high fluence 27 MeV electrons

    Science.gov (United States)

    Joita, A. C.; Nistor, S. V.

    2018-04-01

    Enhancing the long term stable performance of silicon detectors used for monitoring the position and flux of the particle beams in high energy physics experiments requires a better knowledge of the nature, stability, and transformation properties of the radiation defects created over the operation time. We report the results of an electron spin resonance investigation in the nature, transformation, and long term stability of the irradiation paramagnetic point defects (IPPDs) produced by high fluence (2 × 1016 cm-2), high energy (27 MeV) electrons in n-type, P-doped standard floating zone silicon. We found out that both freshly irradiated and aged (i.e., stored after irradiation for 3.5 years at 250 K) samples mainly contain negatively charged tetravacancy and pentavacancy defects in the first case and tetravacancy defects in the second one. The fact that such small cluster vacancy defects have not been observed by irradiation with low energy (below 5 MeV) electrons, but were abundantly produced by irradiation with neutrons, strongly suggests the presence of the same mechanism of direct formation of small vacancy clusters by irradiation with neutrons and high energy, high fluence electrons, in agreement with theoretical predictions. Differences in the nature and annealing properties of the IPPDs observed between the 27 MeV electrons freshly irradiated, and irradiated and aged samples were attributed to the presence of a high concentration of divacancies in the freshly irradiated samples, defects which transform during storage at 250 K through diffusion and recombination processes.

  18. Investigation into the incorporation of H3-labelled thymidine into the DNA of a C3H-tumor after irradiation with 35 MeV electrons

    International Nuclear Information System (INIS)

    Pfersdorff, J.

    1978-01-01

    The radiation effect on the DNA synthesis of an injected tumor in C 3 H-mice is studied. The tumor is a mammary adenocarcinoma injected into the neck of the animals. A betatron of Brown, Boverie and Cie. of the type Asklepitton 35 is used as radiation source for the generation of fast electrons with an energy of 35 MeV applied to the tumor in the animals through an annular tube of 4 cm in diameter, in the given doses. The tumor-doubling rate during the exponential growth phase is computed to be td = 3.65 days. During irradiation of the tumor, the DNA synthesis is determined by measuring the incorporation of H 3 TdR into the DNA. The results show that the radiation effect on the DNA synthesis is enhanced by every exposure, whereas the additional damage decreases and a recovery can be detected after the first two exposures according to the damage. This study confirms the results of former investigations on tissue cultures. The decisive effect of the radiation is the disturbance of DNA synthesis. Analogous effects can be expected in the irradiation of human tumor cells, though no conclusions can be drawn with regard to fractionation, due to the fast tumor doubling rate of 3.7 days. (orig./MG) [de

  19. Very-High-Brightness Picosecond Electron Source

    International Nuclear Information System (INIS)

    Bluem, H.

    2003-01-01

    Bright, RF photocathode electron guns are the source of choice for most high-performance research accelerator applications. Some of these applications are pushing the performance boundaries of the present state-of-the-art guns. Advanced Energy Systems is developing a novel photocathode RF gun that shows excellent promise for extending gun performance. Initial gun simulations with only a short booster accelerator easily break the benchmark emittance of one micron for 1 nC of bunch charge. The pulse length in these simulations is less than 2 ps. It is expected that with more detailed optimization studies, the performance can be further improved. The performance details of the gun will be presented. In addition, we will discuss the present design concept along with the status of the project

  20. Bremsstrahlung hard x-ray source driven by an electron beam from a self-modulated laser wakefield accelerator

    Science.gov (United States)

    Lemos, N.; Albert, F.; Shaw, J. L.; Papp, D.; Polanek, R.; King, P.; Milder, A. L.; Marsh, K. A.; Pak, A.; Pollock, B. B.; Hegelich, B. M.; Moody, J. D.; Park, J.; Tommasini, R.; Williams, G. J.; Chen, Hui; Joshi, C.

    2018-05-01

    An x-ray source generated by an electron beam produced using a Self-Modulated Laser Wakefield Accelerator (SM-LWFA) is explored for use in high energy density science facilities. By colliding the electron beam, with a maximum energy of 380 MeV, total charge of >10 nC and a divergence of 64 × 100 mrad, from a SM-LWFA driven by a 1 ps 120 J laser, into a high-Z foil, an x/gamma-ray source was generated. A broadband bremsstrahlung energy spectrum with temperatures ranging from 0.8 to 2 MeV was measured with an almost 2 orders of magnitude flux increase when compared with other schemes using LWFA. GEANT4 simulations were done to calculate the source size and divergence.

  1. Comparison of GATE/GEANT4 with EGSnrc and MCNP for electron dose calculations at energies between 15 keV and 20 MeV.

    Science.gov (United States)

    Maigne, L; Perrot, Y; Schaart, D R; Donnarieix, D; Breton, V

    2011-02-07

    The GATE Monte Carlo simulation platform based on the GEANT4 toolkit has come into widespread use for simulating positron emission tomography (PET) and single photon emission computed tomography (SPECT) imaging devices. Here, we explore its use for calculating electron dose distributions in water. Mono-energetic electron dose point kernels and pencil beam kernels in water are calculated for different energies between 15 keV and 20 MeV by means of GATE 6.0, which makes use of the GEANT4 version 9.2 Standard Electromagnetic Physics Package. The results are compared to the well-validated codes EGSnrc and MCNP4C. It is shown that recent improvements made to the GEANT4/GATE software result in significantly better agreement with the other codes. We furthermore illustrate several issues of general interest to GATE and GEANT4 users who wish to perform accurate simulations involving electrons. Provided that the electron step size is sufficiently restricted, GATE 6.0 and EGSnrc dose point kernels are shown to agree to within less than 3% of the maximum dose between 50 keV and 4 MeV, while pencil beam kernels are found to agree to within less than 4% of the maximum dose between 15 keV and 20 MeV.

  2. 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

  3. 1500-MeV fixed-field alternating-gradient synchrotron for a pulsed-spallation neutron source

    International Nuclear Information System (INIS)

    Kustom, R.L.; Khoe, T.K.; Crosbie, E.A.

    1985-01-01

    The first conceptual design of the FFAG for ASPUN was an 1100-MeV, 20-sector machine with an injection radius of 17.5 m and an extraction radius of 18.75 m. The conceptual design currently under study has a higher extraction energy, a larger average radius, but still has 20 sectors. The current interest in higher extraction energy is stimulated by calculations that indicate that the useful neutron production per incident proton is still increasing proportionally up to 1500 MeV. The larger radius also matches existing buildings at Argonne that could be made available for the facility. 11 refs., 4 figs., 3 tabs

  4. Facility for fast neutron irradiation tests of electronics at the ISIS spallation neutron source

    International Nuclear Information System (INIS)

    Andreani, C.; Pietropaolo, A.; Salsano, A.; Gorini, G.; Tardocchi, M.; Paccagnella, A.; Gerardin, S.; Frost, C. D.; Ansell, S.; Platt, S. P.

    2008-01-01

    The VESUVIO beam line at the ISIS spallation neutron source was set up for neutron irradiation tests in the neutron energy range above 10 MeV. The neutron flux and energy spectrum were shown, in benchmark activation measurements, to provide a neutron spectrum similar to the ambient one at sea level, but with an enhancement in intensity of a factor of 10 7 . Such conditions are suitable for accelerated testing of electronic components, as was demonstrated here by measurements of soft error rates in recent technology field programable gate arrays

  5. The GaAs electron source: simulations and experiments

    International Nuclear Information System (INIS)

    Aleksandrov, A.V.; Ciullo, G.; Guidi, V.; Kudelainen, V.I.; Lamanna, G.; Lenisa, P.; Logachov, P.V.; Maciga, B.; Novokhatsky, A.; Tecchio, L.; Yang, B.

    1994-01-01

    In this paper we calculate electron emission from GaAs photocathodes using the Monte Carlo technique. Typical data of energy spread of the electron beam are presented. For photoenergy ranging from 1.6 to 2.1 eV, the calculated longitudinal and transverse energy spreads are 14.4-78 and 4-14.7 meV respectively. Temporal measurement of GaAs photocathodes has been performed. The preliminary results show that the temporal response is faster than 200 ps. (orig.)

  6. DC photoemission electron guns as ERL sources

    International Nuclear Information System (INIS)

    Sinclair, Charles K.

    2006-01-01

    Very-high-voltage DC electron guns, delivering moderate duration bunches from photoemission cathodes, and followed by conventional drift bunching and acceleration, offer a practical solution for an ERL injector. In a variant of this scheme, a DC gun is placed in close proximity to a superconducting RF accelerator cavity, with few or no active elements between the gun and cavity. The principal technical challenge with such electron guns arises from field emission from the cathode electrode and its support structure. Field emission may result in voltage breakdown across the cathode-anode gap, or a punch-through failure of the insulator holding off the cathode potential, as well as lesser though still serious problems. Various means to mitigate these problems are described. The operational lifetime of high quantum efficiency photocathodes in these guns is determined by the vacuum conditions, through phenomena such as chemical poisoning and ion back-bombardment. Minimization of the field strength on electrode structures pushes high-voltage DC guns toward large dimensions and, correspondingly, large outgassing loads, but it is also true that these guns offer many opportunities for achieving excellent vacuum conditions. Good solutions to vacuum problems that had previously limited cathode lifetime have been demonstrated in recent years. Designs for DC guns presently in use and planned for the near future will be described. The parameters necessary for a 100 mA average current, very-high-voltage DC gun with a photocathode operational lifetime greater than 100 h appear to be within reach, but have yet to be demonstrated. A 1 A average current source with good cathode operational lifetime will require developments beyond the present state-of-the-art

  7. The influence of the electron wave function on the Pt Lsub(I) and Lsub(III) ionization probabilities by 3.6 MeV He impact

    International Nuclear Information System (INIS)

    Ullrich, J.; Dangendorf, V.; Dexheimer, K.; Do, K.; Kelbch, C.; Kelbch, S.; Schadt, W.; Schmidt-Boecking, H.; Stiebing, K.E.; Roesel, F.; Trautmann, D.

    1986-01-01

    For 3.6 MeV He impact the Lsub(I) and Lsub(III) subshell ionization probabilities of Pt have been measured. Due to relativistic effects in the electron wave functions, the Lsub(I) subshell ionization probability Isub(LI)(b) is strong enhanced at small impact parameters exceeding even Isub(LIII)(b) in nice agreement with the SCA theory. (orig.)

  8. Observation of enhanced zero-degree binary encounter electron production with decreasing charge-state q in 30 MeV Oq+ + O2 collisions

    International Nuclear Information System (INIS)

    Zouros, T.J.M.; Wong, K.L.; Hidmi, H.I.

    1993-01-01

    We have measured binary encounter electron production in collisions of 30 MeV O q+ projectiles (q=4-8) and O 2 targets. Measured double differential BEe cross-sections are found to increase with decreasing charge-state q, in agreement with similar previously reported zero-degree investigations for H 2 and He targets. However, measurements for the same system but at 25 degrees shows the opposite trend, that BEe cross sections decrease slightly with decreasing charge state

  9. Small-sized linear accelerator of 2.5 MeV electrons with a local radiation shield for custom examination of freight transported by motor transport

    International Nuclear Information System (INIS)

    Baklanov, A.V.; Gavrish, Yu.N.; Klinov, A.P.; Krest'yaninov, A.S.; Nikolaev, V.M.; Fomin, L.P.; Linkenbach, H.A.; Geus, G.; Knospel, W.

    2001-01-01

    A new development of a small-sized linear accelerator of 2.5 MeV electrons with a local radiation protection is described. The accelerator is intended for movable facilities of radiation custom of the freight transported by motor transport. Main constructive solutions, mass and dimension characteristics and results of preliminary tests of the accelerator parameters and characteristics of radiation protection are presented [ru

  10. Liquid argon as an electron/photon detector in the energy range of 50 MeV to 2 GeV: a Monte Carlo investigation

    International Nuclear Information System (INIS)

    Goodman, M.S.; Denis, G.; Hall, M.; Karpovsky, A.; Wilson, R.; Gabriel, T.A.; Bishop, B.L.

    1980-12-01

    Monte Carlo techniques which have been used to study the characteristics of a proposed electron/photon detector based on the total absorption of electromagnetic showers in liquid argon have been investigated. The energy range studied was 50 MeV to 2 GeV. Results are presented on the energy and angular resolution predicted for the device, along with the detailed predictions of the transverse and longitudinal shower distributions. Comparisons are made with other photon detectors, and possible applications are discussed

  11. Electron Beam Diagnosis and Dynamics using DIADYN Plasma Source

    International Nuclear Information System (INIS)

    Toader, D.; Craciun, G.; Manaila, E.; Oproiu, C.; Marghitu, S.

    2009-01-01

    This paper is presenting results obtained with the DIADYN installation after replacing its vacuum electron source (VES L V) with a plasma electron source (PES L V). DIADYN is a low energy laboratory equipment operating with 10 to 50 keV electron beams and designed to help realize non-destructive diagnosis and dynamics for low energy electron beams but also to be used in future material irradiations. The results presented here regard the beam diagnosis and dynamics made with beams obtained from the newly replaced plasma source. We discuss both results obtained in experimental dynamics and dynamics calculation results for electron beams extracted from the SEP L V source.

  12. Ambient-temperature diffusion and gettering of Pt atoms in GaN with surface defect region under 60Co gamma or MeV electron irradiation

    Science.gov (United States)

    Hou, Ruixiang; Li, Lei; Fang, Xin; Xie, Ziang; Li, Shuti; Song, Weidong; Huang, Rong; Zhang, Jicai; Huang, Zengli; Li, Qiangjie; Xu, Wanjing; Fu, Engang; Qin, G. G.

    2018-01-01

    Generally, the diffusion and gettering of impurities in GaN needs high temperature. Calculated with the ambient-temperature extrapolation value of the high temperature diffusivity of Pt atoms in GaN reported in literature, the time required for Pt atoms diffusing 1 nm in GaN at ambient temperature is about 19 years. Therefore, the ambient-temperature diffusion and gettering of Pt atoms in GaN can hardly be observed. In this work, the ambient-temperature diffusion and gettering of Pt atoms in GaN is reported for the first time. It is demonstrated by use of secondary ion mass spectroscopy that in the condition of introducing a defect region on the GaN film surface by plasma, and subsequently, irradiated by 60Co gamma-ray or 3 MeV electrons, the ambient-temperature diffusion and gettering of Pt atoms in GaN can be detected. It is more obvious with larger irradiation dose and higher plasma power. With a similar surface defect region, the ambient-temperature diffusion and gettering of Pt atoms in GaN stimulated by 3 MeV electron irradiation is more marked than that stimulated by gamma irradiation. The physical mechanism of ambient-temperature diffusion and gettering of Pt atoms in a GaN film with a surface defect region stimulated by gamma or MeV electron irradiation is discussed.

  13. Comparative time-series analysis of MeV electron data by Ulysses and Pioneer 10/11 in the Jovian magnetosphere

    Energy Technology Data Exchange (ETDEWEB)

    Dunzlaff, P. [North-West Univ., Potchefstroom (South Africa). Centre for Space Research; Kiel Univ. (Germany). Inst. fuer Experimentelle und Angewandte Physik; Heber, B. [Kiel Univ. (Germany). Inst. fuer Experimentelle und Angewandte Physik; Kopp, A. [Kiel Univ. (Germany). Inst. fuer Experimentelle und Angewandte Physik; North-West Univ., Potchefstroom (South Africa). Centre for Space Research; Potgieter, M.S. [North-West Univ., Potchefstroom (South Africa). Centre for Space Research

    2013-11-01

    The dynamics of the Jovian magnetosphere is dominated by the planet's fast rotation with a period of {proportional_to} 10 h.Within the magnetosphere, this periodicity can in particular be seen in the temporal variation of the spectral index of MeV electrons: every {proportional_to} 10 h the counting rates show a maximum (minimum), while the spectral index shows a minimum (maximum) known as the Jovian ''clock'' mechanism. In this study we re-analyse Ulysses and Pioneer 10/11 data and show that another periodic modulation in the MeV electrons can be identified, manifested by local maxima of the spectral index and local minima of the counting rates. For Ulysses, this modulation can be observed throughout the magnetosphere near the magnetic equator, suggesting an azimuthal asymmetric distribution of MeV electrons near the current sheet. This modulation is found to trail the ''clock'' mechanism by {proportional_to} 3.25 h. The Pioneer 10 data, however, only show occasional evidence of the presence of these local maxima while there is no evidence of this modulation in the Pioneer 11 data. A comparison of the times of observed minor peaks and Ulysses' distance from the current sheet using a simple rigid disc model as well as the model of Khurana and Schwarzl (2005) is performed.

  14. Comparative time-series analysis of MeV electron data by Ulysses and Pioneer 10/11 in the Jovian magnetosphere

    International Nuclear Information System (INIS)

    Dunzlaff, P.; Kiel Univ.; Heber, B.; Kopp, A.; North-West Univ., Potchefstroom; Potgieter, M.S.

    2013-01-01

    The dynamics of the Jovian magnetosphere is dominated by the planet's fast rotation with a period of ∝ 10 h.Within the magnetosphere, this periodicity can in particular be seen in the temporal variation of the spectral index of MeV electrons: every ∝ 10 h the counting rates show a maximum (minimum), while the spectral index shows a minimum (maximum) known as the Jovian ''clock'' mechanism. In this study we re-analyse Ulysses and Pioneer 10/11 data and show that another periodic modulation in the MeV electrons can be identified, manifested by local maxima of the spectral index and local minima of the counting rates. For Ulysses, this modulation can be observed throughout the magnetosphere near the magnetic equator, suggesting an azimuthal asymmetric distribution of MeV electrons near the current sheet. This modulation is found to trail the ''clock'' mechanism by ∝ 3.25 h. The Pioneer 10 data, however, only show occasional evidence of the presence of these local maxima while there is no evidence of this modulation in the Pioneer 11 data. A comparison of the times of observed minor peaks and Ulysses' distance from the current sheet using a simple rigid disc model as well as the model of Khurana and Schwarzl (2005) is performed.

  15. 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

  16. Contribution to deep electron pendulous therapy. Pt. 8. Communication: concerning the problem of diverging contours in telecentric electron pendulous irradiation using the electron energies 10 MeV and 20 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Krause, K; Huedepohl, G; Fees, H; Rassow, J [Essen Univ. (Gesamthochschule) (Germany, F.R.). Abt. fuer Klinische Strahlenphysik

    1978-01-01

    The mode of correction of the isodose curves from telecentric electron pendulous technique using a constant patient radium rsub(p) = 30 cm (Isodosenatlas, Siemens, 1973) is represented with regard to its application in patients with diverging surface contours. Correction is possible by two different methods: 1st by experimental determination of an air gap factor for the shift of isodoses, and 2nd by two factors depending on the focus-skin distance and on the angle of incidence of the electron beam. Determination of the factors is performed either by means of fixed fields measured at vertical and at oblique incidence of the beam and a depth dose distribution measured at the central axis, with oblique incidence of the electrons.

  17. Design of an electron-accelerator-driven compact neutron source for non-destructive assay

    Science.gov (United States)

    Murata, A.; Ikeda, S.; Hayashizaki, N.

    2017-09-01

    The threat of nuclear and radiological terrorism remains one of the greatest challenges to international security, and the threat is constantly evolving. In order to prevent nuclear terrorism, it is important to avoid unlawful import of nuclear materials, such as uranium and plutonium. Development of technologies for non-destructive measurement, detection and recognition of nuclear materials is essential for control at national borders. At Tokyo Institute of Technology, a compact neutron source system driven by an electron-accelerator has been designed for non-destructive assay (NDA). This system is composed of a combination of an S-band (2.856 GHz) RF-gun, a tungsten target to produce photons by bremsstrahlung, a beryllium target, which is suitable for use in generating neutrons because of the low threshold energy of photonuclear reactions, and a moderator to thermalize the fast neutrons. The advantage of this system can accelerate a short pulse beam with a pulse width less than 1 μs which is difficult to produce by neutron generators. The amounts of photons and neutron produced by electron beams were simulated using the Monte Carlo simulation code PHITS 2.82. When the RF-gun is operated with an average electron beam current of 0.1 mA, it is expected that the neutron intensities are 1.19 × 109 n/s and 9.94 × 109 n/s for incident electron beam energies of 5 MeV and 10 MeV, respectively.

  18. Design of a cold neutron source for 25MeV Linac of CAB (Centro Atomico Bariloche - Argentina)

    International Nuclear Information System (INIS)

    Torres, Lourdes

    2006-01-01

    Cold neutrons are widely used in fields of research such as the dynamics of solids and liquids, the investigation of magnetic materials, material science, biology, and nuclear physics in general. Accelerator-based cold neutron sources have already proved to be well adapted to perform neutron scattering studies in all those fields.In this work we present the design of a cold neutron source in the electron Linac-based pulsed source at Centro Atomico Bariloche.The objective of this work is to develop an inexpensive yet efficient cold source with a simple moderator material.Although ideal materials for that purpose would be solid methane or liquid H2, due to economical and safety reasons light water ice, benzene or solid mesitylene were considered as cold moderators. In order to proceed with the design and optimization process of the neutron source, total cross sections for light water ice, benzene and mesitylene were measured at low temperature and thermal nuclear data libraries for such materials had to be developed.The purpose of these calculations was to optimize shape and size for the moderator at a working temperature.To calculations were performed using the MCNP-4C code and our libraries, together with files for (free-atom) carbon, hydrogen and oxygen at that temperature.The geometry studied consisted of a neutron source and different moderator (slab, cylindrical slab, grids, and sets premoderator - moderator with and without coupled).To simplify the system cooler, the slab geometry was changed to a coin shaped moderator using liquid nitrogen as cooler.From the variety of simulations performed, it was clear that a premoderator was necessary to obtain higher intensities.Furthermore, with a premoderator the thickness of the moderator was reduced, simplifying the cooling system.Finally, we adopted for our cold neutron source, a slab premoderator of PLE at room temperature, and a cylindrical moderator of mesitylene at 89K with a cooler system of stainless steel with

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

    Science.gov (United States)

    Ballester, Facundo; Granero, Domingo; Pérez-Calatayud, José; Melhus, Christopher S; Rivard, Mark J

    2009-09-01

    The region of electronic disequilibrium near photon-emitting brachytherapy sources of high-energy radionuclides (60Co, 137CS, 192Ir, and 169Yb) and contributions to total dose from emitted electrons were studied using the GEANT4 and PENELOPE Monte Carlo codes. 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-, 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 192Ir mHDR-v2 source model (Nucletron B.V., Veenendaal, The Netherlands) was simulated for comparison to spherical source results and to published data. Electronic equilibrium within 1% is reached for 60Co, 137CS, 192Ir, and 169Yb 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 60Co and 192Ir, respectively. Electron emissions become important (i.e., > 0.5%) within 3.3 mm of 60Co and 1.7 mm of 192Ir sources, yet are negligible over all distances for 137Cs and 169Yb. 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. 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.

  20. Calculation of equivalent dose index for electrons from 5,0 to 22,0 MeV by the Monte Carlo method

    International Nuclear Information System (INIS)

    Peixoto, J.E.

    1979-01-01

    The index of equivalent dose in depth and in a sphere surface of a soft tissue equivalent material were determined by Monte Carlo method for electron irradiations from 5,0 to 22.00 MeV. The effect of different irradiation geometries which simulate the incidence of onedirectional opposite rotational and isotropic beams was studied. It is also shown that the detector of wall thickness with 0.5g/cm 2 and isotropic response com be used to measure index of equivalent dose for fast electrons. The alternative concept of average equivalent dose for radiation protection is discussed. (M.C.K.) [pt

  1. Multiple ionization of noble gases by 2.0 MeV proton impact: comparison with equi-velocity electron impact ionization

    International Nuclear Information System (INIS)

    Melo, W.S.; Santos, A.C.F.; Sant'Anna, M.M.; Sigaud, G.M.; Montenegro, E.C.

    2002-01-01

    Absolute single- and multiple-ionization cross sections of rare gases (He, Ne, Ar, Kr and Xe) have been measured for collisions with 2.0 MeV p + . A comparison is made with equi-velocity electron impact ionization cross sections as well as with the available proton impact data. For the light rare gases the single-ionization cross sections are essentially the same for both proton and electron impacts, but increasing differences appear for the heavier targets. (author). Letter-to-the-editor

  2. 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...

  3. On-site bridge inspection with partial CT by 3.95Mev X-band linac source

    International Nuclear Information System (INIS)

    Wu, Wenjing; Zhu, Haito; Jin, Ming

    2012-01-01

    Since more and more bridges built several decades ago in Japan have become aged and dangerous, the non-destructive evaluation of those bridges is really an urgent problem. CT system with portable 3.95MeV linacs for bridge inspection is considered to work on-site, considering the law of Japanese radiation protection allows using linacs up to 4MeV outside radiation controlled area. The system would confirm the internal steel situation of bridges and analyze structural strain and stress with 3D model built from sectional imaging to evaluate load-bearing performance. The reconstruction process of bridge imaging is based on partial scanned data because bridge shape confines possible scanning angle to smaller than 180deg and a few translations. A small concrete sample with internal steel bars and attachment accessories is scanned in laboratory as preliminary work. (author)

  4. Neutron detection time distributions of multisphere LiI detectors and AB rem meter at a 20 MeV electron linac

    International Nuclear Information System (INIS)

    Liu, J.C.; Rokni, S.; Vylet, V.; Arora, R.; Semones, E.; Justus, A.

    1997-01-01

    Neutron detection time distribution is an important factor for the dead-time correction for moderator type neutron detectors used in pulsed radiation fields. Measurements of the neutron detection time distributions of multisphere LiL detectors (2''3'' , 5'', 8'', 10'' and 12'' in diameter) and an AB rem meter were made inside an ANL 20 MeV electron linac room. Calculations of the neutron detection time distributions were also made using Monte Carlo codes. The first step was to calculate the neutron energy spectra at the target and detector positions, using a coupled EGS4-MORSE code with a giant-resonant photoneutron generation scheme. The calculated detector spectrum was found in agreement with the multisphere measurements. Then, neutrons hitting the detector surface were scored as a function of energy and the travel time in the room using MCNP. Finally, the above neutron fluence as a function of energy and travel time was used as the source term, and the neutrons detected by 6 Li or 10 B in the sensor were scored as a function of detection time for each detector using MCNP. The calculations of the detection time distributions agree with the measurements. The results also show that the detection time distributions of detectors with large moderators depend mainly on the moderator thickness and neutron spectrum. However, for small detectors, the neutron travel time in the field is also crucial. Therefore, all four factors (neutron spectrum, neutron travel time in the field, detector moderator thickness and detector response function) may play inter-related roles in the detection time distribution of moderator type detectors. (Author)

  5. Feasibility studies of a polarized positron source based on the Bremsstrahlung of polarized electrons

    International Nuclear Information System (INIS)

    Dumas, J.

    2011-09-01

    The nuclear and high-energy physics communities have shown a growing interest in the availability of high current, highly-polarized positron beams. A sufficiently energetic polarized photon or lepton incident on a target may generate, via Bremsstrahlung and pair creation within a solid target foil, electron-positron pairs that should carry some fraction of the initial polarization. Recent advances in high current (> 1 mA) spin polarized electron sources at Jefferson Lab offer the perspective of creating polarized positrons from a low energy electron beam. This thesis discusses polarization transfer from electrons to positrons in the perspective of the design optimization of a polarized positron source. The PEPPo experiment, aiming at a measurement of the positron polarization from a low energy (< 10 MeV) highly spin polarized electron beam is discussed. A successful demonstration of this technique would provide an alternative scheme for the production of low energy polarized positrons and useful information for the optimization of the design of polarized positron sources in the sub-GeV energy range. (author)

  6. Electron cyclotron resonance (ECR) ion sources

    International Nuclear Information System (INIS)

    Jongen, Y.

    1984-05-01

    Starting with the pioneering work of R. Geller and his group in Grenoble (France), at least 14 ECR sources have been built and tested during the last five years. Most of those sources have been extremely successful, providing intense, stable and reliable beams of highly charged ions for cyclotron injection or atomic physics research. However, some of the operational features of those sources disagreed with commonly accepted theories on ECR source operation. To explain the observed behavior of actual sources, it was found necessary to refine some of the crude ideas we had about ECR sources. Some of those new propositions are explained, and used to make some extrapolations on the possible future developments in ECR sources

  7. Production of accelerated electrons near an electron source in the plasma resonance region

    International Nuclear Information System (INIS)

    Fedorov, V.A.

    1989-01-01

    Conditions of generation of plasma electrons accelerated and their characteristics in the vicinity of an electron source are determined. The electron source isolated electrically with infinitely conducting surface, being in unrestricted collisionless plasma ω 0 >>ν, where ω 0 - plasma frequency of nonperturbated plasma, ν - frequency of plasma electron collisions with other plasma particles, is considered. Spherically symmetric injection of electrons, which rates are simulated by ω frequency, occurs from the source surface. When describing phenomena in the vicinity of the electron source, one proceeds from the quasihydrodynamic equation set

  8. 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

  9. RTNS-II: experience at 14-MeV source strengths between 1 x 1013 and 4 x 1013 n/s

    International Nuclear Information System (INIS)

    Davis, J.C.

    1986-05-01

    The design concepts, operational experience, and modifications of the two RTNS-II (Rotating Target Neutron Source-II) 14 MeV neutron sources are reviewed. The original design called for operation at a peak neutron source strength of 4 x 10 13 n/cm 2 s. The facility was to operate at high plant factor and at an acceptable cost in both dose delivered to operating staff and releases to the environment. The possibilities of higher source strengths are discussed in light of the operating experience to date and of new technologies that may be applied to the problems of high flux generators of this type. Changes in ancillary equipment that would provide more efficient or safe operation are also indicated

  10. 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.

  11. Irradiation effects of 6 MeV electron on electrical properties of Al/Al2O3/n-Si MOS capacitors

    International Nuclear Information System (INIS)

    Laha, P.; Banerjee, I.; Bajaj, A.; Chakraborty, P.; Barhai, P.K.; Dahiwale, S.S.; Das, A.K.; Bhoraskar, V.N.; Kim, D.; Mahapatra, S.K.

    2012-01-01

    The influence of 6 MeV electron irradiation on the electrical properties of Al/Al 2 O 3 /n-Si metal–oxide–semiconductor (MOS) capacitors has been investigated. Using rf magnetron sputtering deposition technique, Al/Al 2 O 3 /n-Si MOS capacitors were fabricated and such twelve capacitors were divided into four groups. The first group of MOS capacitors was not irradiated with 6 MeV electrons and treated as virgin. The second group, third group and fourth group of MOS capacitors were irradiated with 6 MeV electrons at 10 kGy, 20 kGy, and 30 kGy doses, respectively, keeping the dose rate ∼1 kGy/min. The variations in crystallinity of the virgin and irradiated MOS capacitors have been compared from GIXRD (Grazing Incidence X-ray Diffraction) spectra. Thickness and in-depth elemental distributions of individual layers were performed using Secondary Ion Mass Spectrometry (SIMS). The device parameters like flat band voltage (V FB ) and interface trap density (D it ) of virgin and irradiated MOS capacitors have been calculated from C vs V and G/ω vs V curve, respectively. The electrical properties of the capacitors were investigated from the tan δ vs V graph. The device parameters were estimated using C–V and G/ω–V measurements. Poole–Frenkel coefficient (β PF ) of the MOS capacitors was determined from leakage current (I)–voltage (V) measurement. The leakage current mechanism was proposed from the β PF value. - Highlights: ► The electron irradiation effects make variation in the device parameters. ► The device parameters changes due to percentage of defects and charge trapping. ► Leakage current of Al/Al 2 O 3 /n-Si changes due to interface dangling bonds. ► The leakage current mechanism of MOS structures is due to Poole-Frenkel effect.

  12. Measurement of electron beams profile of pierce type electron source using sensor of used Tv tube

    International Nuclear Information System (INIS)

    Darsono; Suhartono; Suprapto; Elin Nuraini

    2015-01-01

    The measurement of an electron beam profile has been performed using electron beam monitor based on method of phosphorescent materials. The main components of the electron beam monitor consists of a fluorescent sensor using a used Tv tube, CCTV camera to record images on a Tv screen, video adapter as interface between CCTV and laptop, and the laptop as a viewer and data processing. Two Pierce-type electron sources diode and triode was measured the shape of electron beam profile in real time. Results of the experiments showed that the triode electron source of Pierce type gave the shape of electron beam profiles better than that of the diode electron source .The anode voltage is not so influential on the beam profile shape. The focused voltage in the triode electron source is so influence to the shape of the electron beam profile, but above 5 kV no great effect. It can be concluded that the electron beam monitor can provide real time observations and drawings shape of the electron beam profile displayed on the used Tv tube glass screen which is the real picture of the shape of the electron beam profile. Triode electron source produces a better electron beam profile than that of the diode electron source. (author)

  13. Preliminary conceptual design for a 510 MeV electron/positron injector for a UCLA φ factory

    International Nuclear Information System (INIS)

    Dahlbacka, G.; Hartline, R.; Barletta, W.; Pellegrini, C.

    1991-01-01

    UCLA is proposing a compact suer conducting high luminosity (10 32-33 cm -2 sec -1 ) e + e - collider for a φ factory. To achieve the required e + e - currents, full energy injections from a linac with intermediate storage in a Positron Accumulator Ring (PAR) is used. The elements of the linac are outlined with cost and future flexibility in mind. The preliminary conceptual design starts with a high current gun similar in design to those developed at SLAC and at ANL (for the APS). Four 4-section linac modules follow, each driven by a 60 MW klystron with a 1 μsec macropulse and an average current of 8.6 A. The first 4-section model is used to create positrons in a tungsten target at 186 MeV. The three remaining three modules are used to accelerate the e + e - beam to 558 MeV (no load limit) for injection into the PAR

  14. Positron probing of open vacancy volume of phosphorus-vacancy complexes in float-zone n-type silicon irradiated by 0.9-MeV electrons and by 15-MeV protons

    Energy Technology Data Exchange (ETDEWEB)

    Arutyunov, Nikolay [Department of Physics, Martin Luther University Halle (Germany); Ioffe Physico-Technical Institute, St. Petersburg (Russian Federation); Institute of Ion-Plasma and Laser Technologies (Institute of Electronics), Tashkent (Uzbekistan); Emtsev, Vadim; Oganesyan, Gagik [Ioffe Physico-Technical Institute, St. Petersburg (Russian Federation); Elsayed, Mohamed [Department of Physics, Martin Luther University Halle (Germany); Faculty of Science, Department of Physics, Minia University (Egypt); Krause-Rehberg, Reinhard [Department of Physics, Martin Luther University Halle (Germany); Abrosimov, Nikolay [Leibniz Institute for Crystal Growth, Berlin (Germany); Kozlovski, Vitalii [St. Petersburg State Polytechnical University (Russian Federation)

    2017-07-15

    For the first time the samples, cut from the same wafer of crystals of float-zone silicon, n-FZ-Si(P) and n-FZ-Si(Bi), were subjected to irradiation with 0.9-MeV electrons and 15-MeV protons at RT for studying them by low-temperature positron annihilation lifetime spectroscopy. Measurements of Hall effect have been used for the materials characterization. The discussion is focused on the open vacancy volume (V{sub op}) of the thermally stable group-V-impurity-vacancy complexes comprising the phosphorus atoms; the bismuth-related vacancy complexes are briefly considered. The data of positron probing of PV pairs (E-centers), divacancies, and the thermally stable defects in the irradiated n-FZ-Si(P) materials are compared. Beyond a reliable detecting of the defect-related positron annihilation lifetime in the course of isochronal annealing at ∝ 500 C, the recovery of concentration of phosphorus-related shallow donor states continues up to ∝650-700 C. The open vacancy volumes V{sub op} to be characterized by long positron lifetimes Δτ{sub 2} ∝271-289 ps in (gr.-V-atom)-V{sub op} complexes are compared with theoretical data available for the vacancies, τ(V{sub 1}), and divacancies, τ(V{sub 2}). The extended semi-vacancies, 2V{sub s-ext}, and relaxed vacancies, 2V{sub inw}, are proposed as the open volume V{sub op} in (gr.-V-atom)-V{sub op} complexes. It is argued that at high annealing temperature the defect P{sub s}-V{sub op}-P{sub s} is decomposed. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  15. Development of high performance negative ion sources and accelerators for MeV class neutral beam injectors

    International Nuclear Information System (INIS)

    Taniguchi, M.; Hanada, M.; Iga, T.

    2003-01-01

    Operation of accelerator at low pressure is an essential requirement to reduce stripping loss of the negative ions, which in turn results in high efficiency of the NB systems. For this purpose, a vacuum insulated beam source (VIBS) has been developed at JAERI, which reduces the gas pressure in the accelerator by enhanced gas conductance through the accelerator. The VIBS achieves the high voltage insulation of 1 MV by immersing the whole structure of accelerator in vacuum with long (∼ 1.8 m) insulation distance. Results of the voltage holding test using a long vacuum gap of 1.8 m indicate that a transition from vacuum discharge to gas discharge occurs at around 0.2 Pa m in the long vacuum gap. So far, the VIBS succeeded in acceleration of 20 mA (H - ) beam up to 970 keV for 1 s. The high voltage holding capability of the VIBS was drastically improved by installing a new large stress ring, which reduces electric field concentration at the triple junction of the accelerator column. At present the VIBS sustains 1 MV stably for more than 1200 s. Acceleration of ampere class H- beams at high current density is to be started soon to demonstrate ITER relevant beam optics. Operation of negative ion source at low pressure is also essential to reduce the stripping loss. However, it was not so easy to attain high current density H - ions at low pressure, since destruction cross section of the negative ions becomes large if the electron temperature is > 1 eV, in low pressure discharge. Using strong magnetic filter to lower the electron temperature, and putting higher arc discharge power to compensate reduction of plasma density through the filter, an H - ion beam of 310 A/m 2 was extracted at very low pressure of 0.1Pa. This satisfies the ITER requirement of current density at 1/3 of the ITER design pressure (0.3 Pa). (author)

  16. Advances in 14 MeV neutron activation analysis by means of a new intense neutron source

    International Nuclear Information System (INIS)

    Pepelnik, R.; Fanger, H.-U.; Michaelis, W.; Anders, B.

    1982-01-01

    A new intense 14 MeV neutron generator with cylindrical acceleration structure has been put in operation at the GKSS Research Center Geesthacht. The sealed neutron tube is combined with a fast pneumatic rabbit system with particular capabilities for neutron activation analysis involving short-lived reaction products. The sample transfer time is less than 140 ms. The maximum neutron flux available for activation is 5.2x10 10 n/cm 2 s. Theoretical sensitivity predictions made in a previous study have been verified for some important trace elements. As a first application, samples of freeze-dried suspended matter and fishes of the Elbe river were analyzed. (author)

  17. 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.

  18. Electronic information sources access and use for healthcare ...

    African Journals Online (AJOL)

    Background: Access to and use of electronic information sources for clinical decision is the key to the attainment of health related sustainable goals. Therefore, this study was to assess Electronic Information Sources (EIS) access and use for healthcare service among hospitals of Western Oromia, Ethiopia, 2013. Materials ...

  19. Polarized Light Sources for photocathode electron guns at SLAC

    International Nuclear Information System (INIS)

    Woods, M.; Frisch, J.; Witte, K.; Zolotorev, M.

    1992-12-01

    We describe current and future Polarized Light Sources at SLAC for use with photocathode electron guns to produce polarized electron beams. The SLAC experiments SLD and E142 are considered, and are used to define the required parameters for the Polarized Light Sources

  20. An improved electron impact ion source power supply

    International Nuclear Information System (INIS)

    Beaver, E.M.

    1974-01-01

    An electron impact ion source power supply has been developed that offers improved ion beam stability. The electrical adjustments of ion source parameters are more flexible, and safety features are incorporated to protect the electron emitting filament from accidental destruction. (author)

  1. Small compact pulsed electron source for radiation technologies

    International Nuclear Information System (INIS)

    Korenev, Sergey

    2002-01-01

    The small compact pulsed electron source for radiation technologies is considered in the report. The electron source consists of pulsed high voltage Marx generator and vacuum diode with explosive emission cathode. The main parameters of electron source are next: kinetic energy is 100-150 keV, beam current is 5-200 A and pulse duration is 100-400 nsec. The distribution of absorbed doses in irradiated materials is considered. The physical feasibility of pulsed low energy electron beam for applications is considered

  2. Electron cyclotron resonance microwave ion sources for thin film processing

    International Nuclear Information System (INIS)

    Berry, L.A.; Gorbatkin, S.M.

    1990-01-01

    Plasmas created by microwave absorption at the electron cyclotron resonance (ECR) are increasingly used for a variety of plasma processes, including both etching and deposition. ECR sources efficiently couple energy to electrons and use magnetic confinement to maximize the probability of an electron creating an ion or free radical in pressure regimes where the mean free path for ionization is comparable to the ECR source dimensions. The general operating principles of ECR sources are discussed with special emphasis on their use for thin film etching. Data on source performance during Cl base etching of Si using an ECR system are presented. 32 refs., 5 figs

  3. Principal and experimental study of source of polarized electrons

    International Nuclear Information System (INIS)

    Shang Rencheng; Gao Junfang; Xiao Yuan; Pang Wenning; Deng Jingkang

    1999-01-01

    The getting of polarized electrons was briefly introduced, that is the source of polarized electrons. The measurement of polarization in future, the application of polarized electrons in atomic and molecular physics, condensed physics, biological physics, nuclear and particle physics were discussed

  4. Response of a multi-element dosimeter to calibrated beta sources with E/sub max/ from 0.23 to 3.5 MeV

    International Nuclear Information System (INIS)

    Endres, G.W.R.; Scherpelz, R.I.; Roberson, P.L.

    1982-06-01

    The responses of several different dosimeter absorber systems were studied to determine their usefulness in beta radiation fields. Exposures to several different beta emitters were conducted at the PNL Calibrations Laboratory. The sources used are: 147 Pm, 85 Kr, U(nat), 90 Sr- 90 Y, and 106 Ru- 106 Rh. The maximum energy of these beta emitters varies from 0.23 to 3.5 MeV. The beta sources are calibrated for absorbed dose to tissue at a depth of 0.007 cm. Measurements of response for 4, 5, and 7 element versions of the dosimeter were made. All data reported were obtained from sets of three TLDs exposed under each absorber and for each of the radiation sources

  5. Effect of tissue inhomogeneity on dose distribution of point sources of low-energy electrons

    International Nuclear Information System (INIS)

    Kwok, C.S.; Bialobzyski, P.J.; Yu, S.K.; Prestwich, W.V.

    1990-01-01

    Perturbation in dose distributions of point sources of low-energy electrons at planar interfaces of cortical bone (CB) and red marrow (RM) was investigated experimentally and by Monte Carlo codes EGS and the TIGER series. Ultrathin LiF thermoluminescent dosimeters were used to measure the dose distributions of point sources of 204 Tl and 147 Pm in RM. When the point sources were at 12 mg/cm 2 from a planar interface of CB and RM equivalent plastics, dose enhancement ratios in RM averaged over the region 0--12 mg/cm 2 from the interface were measured to be 1.08±0.03 (SE) and 1.03±0.03 (SE) for 204 Tl and 147 Pm, respectively. The Monte Carlo codes predicted 1.05±0.02 and 1.01±0.02 for the two nuclides, respectively. However, EGS gave consistently 3% higher dose in the dose scoring region than the TIGER series when point sources of monoenergetic electrons up to 0.75 MeV energy were considered in the homogeneous RM situation or in the CB and RM heterogeneous situation. By means of the TIGER series, it was demonstrated that aluminum, which is normally assumed to be equivalent to CB in radiation dosimetry, leads to an overestimation of backscattering of low-energy electrons in soft tissue at a CB--soft-tissue interface by as much as a factor of 2

  6. Radiation Shielding Analyses of A 10 MeV, 15kW LINAC for Electron Beam and X-ray at KACST

    Energy Technology Data Exchange (ETDEWEB)

    Kang, W. G.; Pyo, S. H.; Han, B. S.; Kang, C. M. [EB Tech Co., Daejeon (Korea, Republic of); Alkhuraiji, T. S. [King AbdulAziz City for Science and Technology, Riyadh (Saudi Arabia)

    2016-10-15

    The King AbdulAziz City for Science and Technology (KACST) in the Kingdom of Saudi Arabia has a plan to build a 10 MeV, 15kW linear accelerator (LINAC) for electron beam and X-ray, which is to be supplied by EB Tech in Republic of Korea. The design and construction of the accelerator building will be carried out jointly between EB Tech and KACST. Recommendations for the design and installation of radiation shielding for x-ray and gamma-ray can be found in NCRP No. 49(1976) and for accelerators with energies over 10 MeV in NCRP No. 151 (2005). Monte Carlo calculations were conducted using the MCNP6 code to determine photon fluxes and doses at the point detectors locations around the accelerator building. The problem was run as an electron, photon and neutron transport problem to account for all reactions including the (γ,n) reaction. The detectors where the DXTRAN spheres were used are indicated in the table. The computation was continued until electrons reached a total of 1x10{sup +8} histories.

  7. ESR response of powder samples of clear fused quartz material to high doses of 10 MeV electrons: possible applications for industrial radiation processing

    International Nuclear Information System (INIS)

    Aliabadi, R.; Amraei, R.; Ranjbar, A.H.; Rafieian, Sh.; Nasirimoghadam, S.

    2010-01-01

    Powder samples of clear fused quartz were irradiated by 10 MeV electrons at doses between 6-15 kGy and 25-37 kGy and analyzed with electron spin resonance. The reproducibility of the material dose response curve was studied, in which the irradiated samples were annealed and reused for further investigations. Results indicate a good linearity between the absorbed dose and the ESR intensity of the signals. They also showed that in the reuse processes, the electron spin resonance signal intensity, in both dose ranges was decreased. The thermal fading represented a relative sharp decay at room temperature through 15 days, after which the decay-rate was negligible for a measurement period of 60 days.

  8. Structural and electrical properties of polycrystalline CdSe thin films, before and after irradiation with 6 MeV accelerated electrons

    International Nuclear Information System (INIS)

    Ion, L.; Antohe, V.A.; Tazlaoanu, C.; Antohe, S.; Scarlat, F.

    2004-01-01

    Structural and electrical properties of polycrystalline CdSe thin films irradiated with high-energy electrons are analyzed. The samples were prepared by vacuum deposition of CdSe powder onto optical glass substrate. Their structure and the temperature dependence of the electrical resistance were determined, both before and after irradiation with 6 MeV electrons at fluencies up to 10 16 electrons/cm 2 . There were no measurable changes in the crystalline structure of the films after irradiation. Electrical properties are controlled by the defect level of donor type, possibly a selenium vacancy, with two ionizing states having ionization energies of about 0.40 eV and 0.22 eV, respectively. The major effect of the irradiation is to increase significantly the concentration of these defects. (authors)

  9. Projectile-charge-state dependence of 0 degree binary-encounter electron production in 30-MeV Oq++O2 collisions

    International Nuclear Information System (INIS)

    Zouros, T.J.M.; Richard, P.; Wong, K.L.; Hidmi, H.I.; Sanders, J.M.; Liao, C.; Grabbe, S.; Bhalla, C.P.

    1994-01-01

    Double-differential cross sections (DDCS's) for the production of binary-encounter electrons (BEE's) are reported for 30-MeV O q+ +O 2 collisions. The BEE DDCS's were measured at θ=0 degree with respect to the beam direction for projectile charge states q=4--8. The measured BEE DDCS's were found to increase with decreasing charge state in agreement with other recent BEE results employing simpler H 2 and He targets. Impulse-approximation calculations of BEE production for θ=0 degree--45 degree are also presented, in which it is assumed that target electrons undergo elastic scattering in the screened Coulomb field of the projectile ion. These calculations are shown to be in agreement with our data at θ=0 degree where only 2s and 2p target electrons are considered

  10. Simulation of MeV electron energy deposition in CdS quantum dots absorbed in silicate glass for radiation dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Baharin, R; Hobson, P R; Smith, D R, E-mail: ruzalina.baharin@brunel.ac.u [Centre for Sensors and Instrumentation, School of Engineering and Design, Brunel University, Uxbridge UB8 3PH (United Kingdom)

    2010-09-01

    We are currently developing 2D dosimeters with optical readout based on CdS or CdS/CdSe core-shell quantum-dots using commercially available materials. In order to understand the limitations on the measurement of a 2D radiation profile the 3D deposited energy profile of MeV energy electrons in CdS quantum-dot-doped silica glass have been studied by Monte Carlo simulation using the CASINO and PENELOPE codes. Profiles for silica glass and CdS quantum-dot-doped silica glass were then compared.

  11. Simulation of MeV electron energy deposition in CdS quantum dots absorbed in silicate glass for radiation dosimetry

    International Nuclear Information System (INIS)

    Baharin, R; Hobson, P R; Smith, D R

    2010-01-01

    We are currently developing 2D dosimeters with optical readout based on CdS or CdS/CdSe core-shell quantum-dots using commercially available materials. In order to understand the limitations on the measurement of a 2D radiation profile the 3D deposited energy profile of MeV energy electrons in CdS quantum-dot-doped silica glass have been studied by Monte Carlo simulation using the CASINO and PENELOPE codes. Profiles for silica glass and CdS quantum-dot-doped silica glass were then compared.

  12. Yields of Radionuclides Created by Photonuclear Reactions on Be, C, Na, Cl, and Ge, Using Bremsstrahlung of 150-MeV Electrons

    International Nuclear Information System (INIS)

    Dickens, J.K.

    2001-01-01

    The bremsstrahlung created by 150-MeV electrons impinging on a tantalum radiator was used to study photonuclear reactions on samples containing Be, C, Na, Cl and Ge. For Ge fifteen radioisotopes, ranging in half life between 2.6 min and 271 days, and in mass between 65 and 75, were obtained in sufficient amount to determine their yields quantitatively using known decay gamma-rays. Special equipment is described which was developed to create the bremsstrahlung using a beam-sharing mode, while minimizing the neutron flux on the sample. Relative production rates were determined. These were analyzed to provide absolute average cross sections for production of three reactions

  13. Dedicated Tool for Irradiation and Electrical Measurement of Large Surface Samples on the Beamline of a 2.5 Mev Pelletron Electron Accelerator: Application to Solar Cells

    OpenAIRE

    Lefèvre Jérémie; Le Houedec Patrice; Losco Jérôme; Cavani Olivier; Boizot Bruno

    2017-01-01

    We designed a tool allowing irradiation of large samples over a surface of A5 size dimension by means of a 2.5 MeV Pelletron electron accelerator. in situ electrical measurements (I-V, conductivity, etc.) can also be performed, in the dark or under illumination, to study radiation effects in materials. Irradiations and electrical measurements are achievable over a temperature range from 100 K to 300 K. The setup was initially developed to test real-size triple junction solar cells at low t...

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

    International Nuclear Information System (INIS)

    Lucero, J. F.; Rojas, J. I.

    2016-01-01

    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.

  15. 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.

  16. The synthesis method for design of electron flow sources

    Science.gov (United States)

    Alexahin, Yu I.; Molodozhenzev, A. Yu

    1997-01-01

    The synthesis method to design a relativistic magnetically - focused beam source is described in this paper. It allows to find a shape of electrodes necessary to produce laminar space charge flows. Electron guns with shielded cathodes designed with this method were analyzed using the EGUN code. The obtained results have shown the coincidence of the synthesis and analysis calculations [1]. This method of electron gun calculation may be applied for immersed electron flows - of interest for the EBIS electron gun design.

  17. Electron Beam Diagnosis and Dynamics using DIADYN Plasma Source

    Energy Technology Data Exchange (ETDEWEB)

    Toader, D; Craciun, G; Manaila, E; Oproiu, C [National Institute of Research for Laser, Plasma and Radiation Physics Bucuresti (Romania); Marghitu, S [ICPE Electrostatica S.A - Bucuresti (Romania)

    2009-11-15

    This paper is presenting results obtained with the DIADYN installation after replacing its vacuum electron source (VES{sub L}V) with a plasma electron source (PES{sub L}V). DIADYN is a low energy laboratory equipment operating with 10 to 50 keV electron beams and designed to help realize non-destructive diagnosis and dynamics for low energy electron beams but also to be used in future material irradiations. The results presented here regard the beam diagnosis and dynamics made with beams obtained from the newly replaced plasma source. We discuss both results obtained in experimental dynamics and dynamics calculation results for electron beams extracted from the SEP{sub L}V source.

  18. Preparation of 3-7 MeV neutron source and preliminary results of activation cross section measurement

    Energy Technology Data Exchange (ETDEWEB)

    Furuta, T.; Masuda, T.; Tsurita, Y.; Hashimoto, A.; Miyajima, N. [Department of Nuclear Engineering, Nagoya University, Nagoya, Aichi (Japan); Sakane, H.; Shibata, M.; Yamamoto, H.; Kawade, K.

    1999-03-01

    A d-D gas target producing monoenergetic neutrons has been constructed for measurement of activation cross sections in the energy region of 3 to 7 MeV at Van de Graaff accelerator of Nagoya University. Neutron spectra and neutron fluxes were measured as a function of the incident deuteron energy. Preliminary results of activation cross sections were obtained for reactions {sup 27}Al(n, p){sup 27}Mg, {sup 27}Al(n, {alpha}){sup 24}Na, {sup 47}Ti(n, p){sup 47}Sc, {sup 56}Fe(n, p){sup 56}Mn, {sup 58}Ni(n, p){sup 58}Co and {sup 64}Zn(n, p){sup 64}Cu. The results are compared with the evaluated values of JENDL-3.2. A well-type HPGe detector was used for highly efficient detection. (author)

  19. Electron beam dynamics in Pasotron microwave sources

    International Nuclear Information System (INIS)

    Carmel, Y.; Shkvarunets, A.; Nusinovich, G.S.; Rodgers, J.; Bliokh, Yu.P.; Goebel, D.M.

    2003-01-01

    The Pasotron is a high efficiency (∼50%), plasma-assisted microwave generator in which the beam electrons exhibit two-dimensional motion in the slow wave structure. The electron beam propagates in the ion-focusing regime (Bennett pinch regime) because there is no applied magnetic field. Since initially only the neutral gas is present in the vacuum system and the ions in the neutralizing plasma channel are produced only due to the beam impact ionization, the beam dynamics in Pasotrons is inherently a nonstationary process, and important for efficient operation. The present paper contains results of experimental studies of stationary and nonstationary effects in the beam dynamics in Pasotrons and their theoretical interpretation

  20. Investigation of ionization losses of shower electrons in electron-photon shower developed in liquid xenon by gamma quanta in the energy range 1600-3400 MeV

    International Nuclear Information System (INIS)

    Okhrymenko, L.S.; Slowinski, B.; Strugalski, Z.; Sredniawa, B.

    1975-01-01

    Results of the investigation of differential distributions of ionization losses and the corresponding fluctuations for shower electrons in the longitudinal development of electron-photon showers produced by gamma-quanta of energies Esub(γ)=1600-3400 MeV in liquid xenon are given. A simple and convenient from the methodical point of view two-parametric function, approximating the observed distribution has been obtained. The independence of the fluctuations of ionization losses of shower electrons on the energy of gamma-quanta in the investigated interval of Esub(γ) values has been found

  1. Modifications in the structural and optical properties of nanocrystalline CaWO4 induced by 8 MeV electron beam irradiation

    International Nuclear Information System (INIS)

    Aloysius Sabu, N.; Priyanka, K.P.; Ganesh, Sanjeev; Varghese, Thomas

    2016-01-01

    In this article we report the post irradiation effects in the structural and optical properties of nanocrystalline calcium tungstate synthesized by chemical precipitation and heat treatment. The samples were subjected to different doses of high-energy electron beam obtained from an 8 MeV Microton. Investigations using X-ray diffraction, scanning electron microscopy and Raman spectra confirmed changes in particle size and structural parameters. However, no phase change was detected for irradiated samples. The stretching/compressive strain caused by high energy electrons is responsible for the slight shift in the XRD peaks of irradiated samples. Modifications in the morphology of different samples were confirmed by scanning electron microscopy. Ultraviolet-visible absorption studies showed variations in the optical band gap (4.08–4.25 eV) upon electron-beam irradiation. New photoluminescence behaviour in electron beam irradiated nanocrystalline CaWO 4 was evidenced. A blue shift of the PL peak with increase in intensity was observed in all the irradiated samples. - Highlights: • Calcium tungstate nanocrystals are synthesized by simple chemical precipitation method. • Electron beam induced modifications in the structural and optical properties are investigated. • New photoluminescence behaviour is evidenced due to beam irradiation.

  2. Coherent properties of a tunable low-energy electron-matter-wave source

    Science.gov (United States)

    Pooch, A.; Seidling, M.; Kerker, N.; Röpke, R.; Rembold, A.; Chang, W. T.; Hwang, I. S.; Stibor, A.

    2018-01-01

    A general challenge in various quantum experiments and applications is to develop suitable sources for coherent particles. In particular, recent progress in microscopy, interferometry, metrology, decoherence measurements, and chip-based applications rely on intensive, tunable, coherent sources for free low-energy electron-matter waves. In most cases, the electrons get field emitted from a metal nanotip, where its radius and geometry toward a counter electrode determines the field distribution and the emission voltage. A higher emission is often connected to faster electrons with smaller de Broglie wavelengths, requiring larger pattern magnification after matter-wave diffraction or interferometry. This can be prevented with a well-known setup consisting of two counter electrodes that allow independent setting of the beam intensity and velocity. However, it needs to be tested if the coherent properties of such a source are preserved after the acceleration and deceleration of the electrons. Here, we study the coherence of the beam in a biprism interferometer with a single atom tip electron field emitter if the particle velocity and wavelength varies after emission. With a Wien filter measurement and a contrast correlation analysis we demonstrate that the intensity of the source at a certain particle wavelength can be enhanced up to a factor of 6.4 without changing the transverse and longitudinal coherence of the electron beam. In addition, the energy width of the single atom tip emitter was measured to be 377 meV, corresponding to a longitudinal coherence length of 82 nm. The design has potential applications in interferometry, microscopy, and sensor technology.

  3. The Electron Cyclotron Resonance Light Source Assembly of PTB - ELISA

    CERN Document Server

    Gruebling, P; Ulm, G

    1999-01-01

    In the radiometry laboratory of the Physikalisch-Technische,Bundesanstalt at the Berlin electron storage ring BESSY I, radiation sources for radiometric applications in industry and basic research in the vacuum ultraviolet (VUV) spectral range are developed, characterized and calibrated. Established sources such as deuterium lamps, Penning and hollow cathode discharge sources have limited spectral ranges and in particular their stability and life time suffers from the erosion of the cathode material. To overcome these limitations we have developed a radiation source based on the principle of the electron cyclotron resonance ion source. ELISA is a 10 GHz monomode source with a compact design featuring a tunable cavity and axially positionable permanent magnets. The radiation emission of the source can be detected simultaneously in the VUV and X-ray spectral range via a toroidal grating monochromator and a Si(Li)-detector. The special design of the source allows spectroscopic investigations of the plasma in dep...

  4. Finding legal information a guide to print and electronic sources

    CERN Document Server

    Pester, David

    2003-01-01

    Given the vast amount of legal information available, it is sometimes very difficult - and certainly very time consuming - to know where to start looking for the specific information you require. This book, covering the most up-to-date information sources (printed and electronic), helps guide the reader towards the information they need. It is an accessible and easy-to-use directory of legal information sources for librarians, lawyers, students and anyone needing legal information. The book covers mainly British and European Union law and includes general material and the main subject areas, including online and internet sources. It also lists reference material, such as legal dictionaries and directories. The book is essentially a directory of information sources, with publishing details (including ISBN), and short comments where useful. Electronic sources are mentioned where relevant, with details of scope and any limitations of coverage. Comprehensive and up-to-date (covering electronic sources and importa...

  5. Two-section linear direct-current accelerator of 1.2 MeV electrons. Mean beam current of 50 mA

    International Nuclear Information System (INIS)

    Alimov, A.S.; Ermakov, D.I.; Ishkhanov, B.S.; Shvedunov, V.I.; Sakharov, V.P.; Trower, W.P.

    2002-01-01

    The theoretical and experimental results, obtained by simulation, creation and start-up of the two-section linear electron accelerator, are presented. The following beam parameters: beam current of 49 mA, mean energy of 1.2 MeV, of 59 kV, normalized emittance of 11 mm mrad are determined on the basis of the data on the beam dynamics simulation and the accelerating structure optimization. Special attention is paid to the choice of the version of the SHF-supply system of the two-section accelerator. The version of the SHF-supply system, based on the sections phasing, operating in the auto-oscillation model by means of the synchronizing signal from the feedback chain of the first section into the feedback chain of the second section, is considered. The electron beam parameters on the accelerator outlet (beam current - 44 mA, beam energy - 1.15 MeV, beam efficiency - 50.6 kW) proved to be close to the simulation results [ru

  6. Comparisons of calculated and measured spectral distributions of neutrons from a 14-MeV neutron source inside the Tokamak Fusion Test Reactor

    International Nuclear Information System (INIS)

    Santoro, R.T.; Barnes, J.M.; Alsmiller, R.G. Jr.; Emmett, M.B.; Drischler, J.D.

    1985-12-01

    A recent paper presented neutron spectral distributions (energy greater than or equal to0.91 MeV) measured at various locations around the Tokamak Fusion Test Reactor (TFTR) at the Princeton Plasma Physics Laboratory. The neutron source for the series of measurements was a small D-T generator placed at various positions in the TFTR vacuum chamber. In the present paper the results of neutron transport calculations are presented and compared with these experimental data. The calculations were carried out using Monte Carlo methods and a very detailed model of the TFTR and the TFTR test cell. The calculated and experimental fluences per unit energy are compared in absolute units and are found to be in substantial agreement for five different combinations of source and detector positions

  7. 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

    Energy Technology Data Exchange (ETDEWEB)

    Kozlovski, V.V. [St. Petersburg State Polytechnic University, St. Petersburg 195251 (Russian Federation); Lebedev, A.A., E-mail: shura.lebe@mail.ioffe.ru [Ioffe Physical Technical Institute, Russian Academy of Sciences, St. Petersburg 194021 (Russian Federation); National Research University of Information Technologies, Mechanics, and Optics, St. Petersburg 197101 (Russian Federation); Emtsev, V.V.; Oganesyan, G.A. [Ioffe Physical Technical Institute, Russian Academy of Sciences, St. Petersburg 194021 (Russian Federation)

    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.

  8. Highly efficient electron gun with a single-atom electron source

    International Nuclear Information System (INIS)

    Ishikawa, Tsuyoshi; Urata, Tomohiro; Cho, Boklae; Rokuta, Eiji; Oshima, Chuhei; Terui, Yoshinori; Saito, Hidekazu; Yonezawa, Akira; Tsong, Tien T.

    2007-01-01

    The authors have demonstrated highly collimated electron-beam emission from a practical electron gun with a single-atom electron source; ∼80% of the total emission current entered the electron optics. This ratio was two or three orders of magnitude higher than those of the conventional electron sources such as a cold field emission gun and a Zr/O/W Schottky gun. At the pressure of less than 1x10 -9 Pa, the authors observed stable emission of 20 nA, which generates the specimen current of 5 pA required for scanning electron microscopes

  9. Polarized electron sources for linear colliders

    International Nuclear Information System (INIS)

    Clendenin, J.E.; Ecklund, S.D.; Miller, R.H.; Schultz, D.C.; Sheppard, J.C.

    1992-07-01

    Linear colliders require high peak current beams with low duty factors. Several methods to produce polarized e - beams for accelerators have been developed. The SLC, the first linear collider, utilizes a photocathode gun with a GaAs cathode. Although photocathode sources are probably the only practical alternative for the next generation of linear colliders, several problems remain to be solved, including high voltage breakdown which poisons the cathode, charge limitations that are associated with the condition of the semiconductor cathode, and a relatively low polarization of ≤5O%. Methods to solve or at least greatly reduce the impact of each of these problems are at hand

  10. Comparison of measured with calculated dose distribution from a 120-MeV electron beam from a laser-plasma accelerator

    International Nuclear Information System (INIS)

    Lundh, O.; Rechatin, C.; Faure, J.; Ben-Ismaïl, A.; Lim, J.; De Wagter, C.; De Neve, W.; Malka, V.

    2012-01-01

    Purpose: To evaluate the dose distribution of a 120-MeV laser-plasma accelerated electron beam which may be of potential interest for high-energy electron radiation therapy. Methods: In the interaction between an intense laser pulse and a helium gas jet, a well collimated electron beam with very high energy is produced. A secondary laser beam is used to optically control and to tune the electron beam energy and charge. The potential use of this beam for radiation treatment is evaluated experimentally by measurements of dose deposition in a polystyrene phantom. The results are compared to Monte Carlo simulations using the geant4 code. Results: It has been shown that the laser-plasma accelerated electron beam can deliver a peak dose of more than 1 Gy at the entrance of the phantom in a single laser shot by direct irradiation, without the use of intermediate magnetic transport or focusing. The dose distribution is peaked on axis, with narrow lateral penumbra. Monte Carlo simulations of electron beam propagation and dose deposition indicate that the propagation of the intense electron beam (with large self-fields) can be described by standard models that exclude collective effects in the response of the material. Conclusions: The measurements show that the high-energy electron beams produced by an optically injected laser-plasma accelerator can deliver high enough dose at penetration depths of interest for electron beam radiotherapy of deep-seated tumors. Many engineering issues must be resolved before laser-accelerated electrons can be used for cancer therapy, but they also represent exciting challenges for future research.

  11. Comparison of measured with calculated dose distribution from a 120-MeV electron beam from a laser-plasma accelerator.

    Science.gov (United States)

    Lundh, O; Rechatin, C; Faure, J; Ben-Ismaïl, A; Lim, J; De Wagter, C; De Neve, W; Malka, V

    2012-06-01

    To evaluate the dose distribution of a 120-MeV laser-plasma accelerated electron beam which may be of potential interest for high-energy electron radiation therapy. In the interaction between an intense laser pulse and a helium gas jet, a well collimated electron beam with very high energy is produced. A secondary laser beam is used to optically control and to tune the electron beam energy and charge. The potential use of this beam for radiation treatment is evaluated experimentally by measurements of dose deposition in a polystyrene phantom. The results are compared to Monte Carlo simulations using the geant4 code. It has been shown that the laser-plasma accelerated electron beam can deliver a peak dose of more than 1 Gy at the entrance of the phantom in a single laser shot by direct irradiation, without the use of intermediate magnetic transport or focusing. The dose distribution is peaked on axis, with narrow lateral penumbra. Monte Carlo simulations of electron beam propagation and dose deposition indicate that the propagation of the intense electron beam (with large self-fields) can be described by standard models that exclude collective effects in the response of the material. The measurements show that the high-energy electron beams produced by an optically injected laser-plasma accelerator can deliver high enough dose at penetration depths of interest for electron beam radiotherapy of deep-seated tumors. Many engineering issues must be resolved before laser-accelerated electrons can be used for cancer therapy, but they also represent exciting challenges for future research. © 2012 American Association of Physicists in Medicine.

  12. Microstructural Parameters in 8 MeV Electron-Irradiated BOMBYX MORI Silk Fibers by Wide-ANGLE X-Ray Scattering Studies (waxs)

    Science.gov (United States)

    Sangappa, Asha, S.; Sanjeev, Ganesh; Subramanya, G.; Parameswara, P.; Somashekar, R.

    2010-01-01

    The present work looks into the microstructural modification in electron irradiated Bombyx mori P31 silk fibers. The irradiation process was performed in air at room temperature using 8 MeV electron accelerator at different doses: 0, 25, 50 and 100 kGy. Irradiation of polymer is used to cross-link or degrade the desired component or to fix the polymer morphology. The changes in microstructural parameters in these natural polymer fibers have been computed using wide angle X-ray scattering (WAXS) data and employing line profile analysis (LPA) using Fourier transform technique of Warren. Exponential, Lognormal and Reinhold functions for the column length distributions have been used for the determination of crystal size, lattice strain and enthalpy parameters.

  13. 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......) surrounding a copper wire core show that equal irradiations from as few as four sides give approximately isotropy and satisfactorily uniform energy depositions around the wire circumference. Electron beams of 0.4 MeV maximum energy were used to irradiate wires having a copper core of 1.0 mm dia....... 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...

  14. Radiological Safety Aspects of the operation of the Electron Linear Accelerator Linac CIRCE III 10 MeV

    International Nuclear Information System (INIS)

    Naceur, Ahmed

    2014-01-01

    This document is a report about safety and security for the electron accelerator Linac-CIRCE III of the National Center for Nuclear Sciences and Technologies of Tunis. The paper aims to introduce the standards of the International Atomic Energy Agency (IAEA) to the installation in question. Overall, it draws its profit from the official security reports of the IAEA. First, we study the anatomy of the accelerator by breaking it down into various compartments and examining the case of leaks that may arise. This part introduces the particularity of this installation and allows us to meet and provide procedures for some typical scenarios of mechanical malfunction. Second, we recall and adapt some theoretical concepts related to the quantification of the radioactivity, the thickness of the armoring, the utilization factor, and the quality factor. Thus, we become able to list of types of these radiations, dangers, risks and their sources. We also examine the phenomenon of compartments activation, toxic gases production (including ozone), the process of elimination, the danger associated with X-rays generated by high voltage system and the risk of electrocution. In light of this study, we handle mathematically the question of the armoring and the concept of radiation protection. Therefore, we present a practical methodology to implement a monitoring system and a technicality in the interpretation of the measurements. Finally, we discuss the practical aspect by introducing security governance to CIRCE III, and establishing a program of general, radiological and specific security. Then, we evaluate the areas of typical security, and present a comparative radiological study between the results obtained by the IAEA standards and those by the German DIN 6847 standard for direct Bremsstrahlung radiation and scattered radiation.

  15. Progress on a cryogenically cooled RF gun polarized electron source

    Energy Technology Data Exchange (ETDEWEB)

    Fliller, R.P., III; Edwards, H.; /Fermilab

    2006-08-01

    RF guns have proven useful in multiple accelerator applications. An RF gun capable of producing polarized electrons is an attractive electron source for the ILC or an electron-ion collider. Producing such a gun has proven elusive. The NEA GaAs photocathode needed for polarized electron production is damaged by the vacuum environment in an RF gun. Electron and ion back bombardment can also damage the cathode. These problems must be mitigated before producing an RF gun polarized electron source. In this paper we report continuing efforts to improve the vacuum environment in a normal conducting RF gun by cooling it with liquid nitrogen after a high temperature vacuum bake out. We also report on a design of a cathode preparation chamber to produce bulk GaAs photocathodes for testing in such a gun. Future directions are also discussed.

  16. Secondary electron emission of thin carbon foils under the impact of hydrogen atoms, ions and molecular ions, under energies within the MeV range

    International Nuclear Information System (INIS)

    Vidovic, Z.

    1997-06-01

    This work focuses on the study of the emission statistics of secondary electrons from thin carbon foils bombarded with H 0 , H 2 + and H 3 + 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 2 + and H 3 + 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)

  17. Multiplicity of secondary electrons emitted by carbon thin targets by impact of H0, H2+ and H3+ projectiles at MeV energies

    International Nuclear Information System (INIS)

    Vidovic, Zvonimir

    1997-01-01

    This work focuses on the study of the emission statistics of secondary electrons from thin carbon foils bombarded with H 0 , H 2 + and H 3 + 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 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 2 + and H 3 + 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)

  18. Polarized electronic sources for future e+/e- linear colliders

    International Nuclear Information System (INIS)

    Tang, H.; Alley, R.K.; Clendenin, J.E.

    1997-05-01

    Polarized electron beams will play a crucial role in maximizing the physics potential for future e + /e - linear colliders. We will review the SLC polarized electron source (PES), present a design for a conventional PES for the Next Linear Collider (NLC), and discuss the physics issues of a polarized RF gun

  19. 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.

  20. A study about neutron sources for electron linear acceleractors

    International Nuclear Information System (INIS)

    Goncalez, O.L.

    1982-01-01

    The efficiency of neutron production and residual activity induced by electron incidence from 30 to 200 MeV on thick metalic targets of Al, Sb, Cu, Ir, Hg, Mo, Nb, Ni, Pd, Pt, Ta, Ti, W and Zr is evaluated. As a result of this evaluation, the tantalum, copper and antimony targets are indicated as the more suitable, representating high, low and medium atomic numbers. For the experimental part the Ti, Cu, Nb and Pb were selected as set representatives. The yield measured by the residual activities agree with theoretical calculation. The neutron angular distribution for niobium was measured by indium foil activation. In addition, some general features for 120 0 Cu and Nb spectra were obtained. (Author) [pt

  1. Electron energy recovery system for negative ion sources

    International Nuclear Information System (INIS)

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

    1982-01-01

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

  2. Molecular effects in carbon K-shell Auger-electron production by 0.6-2.0 MeV protons and extraction of an atomic cross section

    International Nuclear Information System (INIS)

    McDaniel, F.D.; Lapicki, G.

    1987-01-01

    Carbon K-shell Auger-electron production cross sections are reported for 0.6-2.0 MeV protons incident on CH 4 (methane), C 2 H 2 (acetylene), C 2 H 4 (ethylene), C 2 H 6 (ethane), n-C 4 H 10 (normal butane), i-C 4 H 10 (isobutane), C 6 H 6 (benzene), CO (carbon monoxide), and CO 2 (carbon dioxide). A constant-energy mode 45 0 parallel-plate electrostatic analyzer was used for detection of Auger electrons. The carbon KLL Auger-electron cross sections for all molecules were found to be lower than that found for CH 4 by 9-23%. All carbon KLL Auger-electron data could be brought into agreement when corrected for the chemical shift of the carbon K-shell binding energy in molecules and for intramolecular scattering. KLL Auger-electron production cross sections are compared to first Born and ECPSSR theories and show good agreement with both after the chemical shift of the carbon K-shell binding energy in molecules and the effects of intramolecular scattering are considered. (orig.)

  3. HOM (higher-order mode) test of the storage ring single-cell cavity with a 20-MeV e- beam for the Advanced Photon Source (APS)

    International Nuclear Information System (INIS)

    Song, J.; Kang, Y.W.; Kustom, R.

    1993-01-01

    To test the effectiveness of damping techniques of the APS storage ring single-cell cavity, a beamline has been designed and assembled to use the ANL Chemistry Division linac beam (20-MeV, FWHM of 20 ps). A single-cell cavity will be excited by the electron beam to investigate the effect on higher-order modes (HOMs) with and without coaxial dampers (H-loop damper, E-probe damper), and wideband aperture dampers. In order for the beam to propagate on- and off-center of the cavity, the beamline consists of two sections -- a beam collimating section and a cavity measurement section -- separated by two double Aluminum foil windows. RF cavity measurements were made with coupling loops and E-probes. The results are compared with both the TBCI calculations and 'cold' measurements with the bead-perturbation method. The data acquisition system and beam diagnostics will be described in a separate paper

  4. Cross sections of electron loss and capture for beams of O+ in water vapor from the energy range of 0,2 to 1,2 MeV

    International Nuclear Information System (INIS)

    Oliveira, Vitor Jesus de

    2015-01-01

    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 + and the water molecule is a Microchannel Plate (MCP) at the position sensitive anode. The collisions of O + 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 describes

  5. 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

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Qiang [College of Nuclear Science and Technology, Harbin Engineering University, Harbin 150001 (China); Shao, Lin, E-mail: lshao@tamu.edu [Department of Nuclear Engineering, Texas A& M University, College Station, TX 77843 (United States)

    2017-03-15

    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.

  6. Grid system design on the plasma cathode electron source

    International Nuclear Information System (INIS)

    Agus Purwadi

    2014-01-01

    It has been designed the grid system on the Plasma Cathode Electron Source (PCES). Grid system with the electron emission hole of (15 x 60) cm 2 , the single aperture grid size of (0,5 x O,5) mm 2 and the grid wire diameter of 0,25 mm, will be used on the plasma generator chamber. If the sum of grid holes known and the value of electron emission current through every the grid hole known too then the total value of electron emission Current which emits from the plasma generator chamber can be determined It has been calculated the value of electron emission current I e as function of the grid radius r e =(0.28, 0.40, 0.49, 0.56, 0.63, 0.69) mm on the electron temperature of T e = 5 eV for varying of the value plasma electron densities n e = (10 15 , 10 16 , 10 17 , 10 18 ) m -3 . Also for the value of electron emission current fe as function of the grid radius r e = (0.28, 0.40, 0.49. 0.56, 0.63,0.69) mm on the electron density n e = 10 17 m -3 for varying of the value of plasma electron temperatures T e = (1, 2, 3, 4, 5) eV. electron emission current will be increase by increasing grid radius, electron temperature as well as plasma electron density. (author)

  7. Ion accumulation and space charge neutralization in intensive electron beams for ion sources and electron cooling

    International Nuclear Information System (INIS)

    Shirkov, G.D.

    1996-01-01

    The Electron Beam Ion Sources (EBIS), Electron Beam Ion Traps (EBIT) and electron beams for electron cooling application have the beam parameters in the same ranges of magnitudes. EBIS and EBIT produce and accumulate ions in the beam due to electron impact ionization. The cooling electron beam accumulates positive ions from the residual gas in the accelerator chamber during the cooling cycle. The space charge neutralization of cooling beam is also used to reduce the electron energy spread and enhance the cooling ability. The advanced results of experimental investigations and theoretical models of the EBIS electron beams are applied to analyze the problem of beam neutralization in the electron cooling techniques. The report presents the analysis of the most important processes connected with ion production, accumulation and losses in the intensive electron beams of ion sources and electron cooling systems for proton and ion colliders. The inelastic and elastic collision processes of charged particles in the electron beams are considered. The inelastic processes such as ionization, charge exchange and recombination change the charge states of ions and neutral atoms in the beam. The elastic Coulomb collisions change the energy of particles and cause the energy redistribution among components in the electron-ion beams. The characteristic times and specific features of ionization, beam neutralization, ion heating and loss in the ion sources and electron cooling beams are determined. The dependence of negative potential in the beam cross section on neutralization factor is studied. 17 refs., 5 figs., 1 tab

  8. Study of hot electrons in a ECR ion source

    International Nuclear Information System (INIS)

    Barue, C.

    1992-12-01

    The perfecting of diagnosis connected with hot electrons of plasma, and then the behaviour of measured parameters of plasma according to parameters of source working are the purpose of this thesis. The experimental results obtained give new information on hot electrons of an ECR ion source. This thesis is divided in 4 parts: the first part presents an ECR source and the experimental configuration (ECRIS physics, minimafios GHz, diagnosis used); the second part, the diagnosis (computer code of cyclotron emission and calibration); the third part gives experimental results in continuous regime (emission cyclotron diagnosis, bremsstrahlung); the fourth part, experimental results in pulsed regime (emission cyclotron diagnosis, diamagnetism) calibration)

  9. Optical Performance of Carbon-Nanotube Electron Sources

    International Nuclear Information System (INIS)

    Jonge, Niels de; Allioux, Myriam; Oostveen, Jim T.; Teo, Kenneth B. K.; Milne, William I.

    2005-01-01

    The figure of merit for the electron optical performance of carbon-nanotube (CNT) electron sources is presented. This figure is given by the relation between the reduced brightness and the energy spread in the region of stable emission. It is shown experimentally that a CNT electron source exhibits a highly stable emission process that follows the Fowler-Nordheim theory for field emission, fixing the relationship among the energy spread, the current, and the radius. The performance of the CNT emitter under realistic operating conditions is compared with state-of-the-art electron point sources. It is demonstrated that the reduced brightness is a function of the tunneling parameter, a measure of the energy spread at low temperatures, only, independent of the geometry of the emitter

  10. A Carbon Nanotube Electron Source Based Ionization Vacuum Gauge

    Energy Technology Data Exchange (ETDEWEB)

    Changkun Dong; Ganapati Myneni

    2003-10-01

    The results of fabrication and performance of an ionization vacuum gauge using a carbon nanotube (CNT) electron source are presented. The electron source was constructed with multi-wall nanotubes (MWNT), which were grown using thermal chemical vapor deposition (CVD) process. The electron emission of the source was stable in vacuum pressure up to 10-7 Torr, which is better than the metal field emitters. The measurement linearity of the gauge was better than {+-}10% from 10-6 to 10-10 Torr. The gauge sensitivity of 4 Torr-1 was achieved under 50 {micro}A electron emission in nitrogen. The gauge is expected to find applications in vacuum measurements from 10-7 Torr to below 10-11 Torr.

  11. Modification of the microstructure and electronic properties of rutile TiO_2 thin films with 79 MeV Br ion irradiation

    International Nuclear Information System (INIS)

    Rath, Haripriya; Dash, P.; Singh, U.P.; Avasthi, D.K.; Kanjilal, D.; Mishra, N.C.

    2015-01-01

    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"1"3 ions cm"−"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_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.

  12. Spatial distribution of bremsstrahlung in water and water-iron by 22-MeV electron bombardment measured with activation detectors

    International Nuclear Information System (INIS)

    Nakamura, Takashi; Nishimoto, Takanao; Hirayama, Hideo.

    1977-01-01

    The spatial distributions of bremsstrahlung in water (1 m thick) and water (60 cm thick)-iron (6.3 cm thick) bombarded by 22-MeV electrons were measured by using a new activation method which we developed. These informations are useful for studying shielding, residual activity and radiation damage of accelerator and target materials. From the measured activities, the bremsstrahlung spectra in water were evaluated with the LYRA and the SAND-II unfolding codes. The evaluated spectra were in good agreement with the analytical calculation by the DIBRE code, except for the higher energy ends. The longitudinal and the lateral distributions of bremsstrahlung flux in water were obtained by integrating the evaluated spectra above 8 MeV. The agreement of the experimental and the calculated flux distributions was very good except for a large angle to beam direction. The total photon number crossing a plane normal to the beam axis attenuates exponentially along the axial depth. The iso-flux contour of bremsstrahlung flux was given by interpolating the flux distribution curves. Only the saturated activities of gold detectors were obtained for water-iron in good experimental accuracy. The spatial distribution of gold saturated activities in water-iron clearly shows the attenuating effect due to strong absorption in iron. (auth.)

  13. Responses of conventional and extended-range neutron detectors in mixed radiation fields around a 150-MeV electron LINAC

    International Nuclear Information System (INIS)

    Lin, Yu-Chi; Sheu, Rong-Jiun; Chen, Ang-Yu

    2015-01-01

    This study analyzed the responses of two types of neutron detector in mixed gamma-ray and neutron radiation fields around a 150-MeV electron linear accelerator (LINAC). The detectors were self-assembled, high efficiency, and designed in two configurations: (1) a conventional moderated-type neutron detector based on a large cylindrical He-3 proportional counter; and (2) an extended-range version with an embedded layer of lead in the moderator to increase the detector’s sensitivity to high-energy neutrons. Two sets of the detectors were used to measure neutrons at the downstream and lateral locations simultaneously, where the radiation fields differed considerably in intensities and spectra of gamma rays and neutrons. Analyzing the detector responses through a comparison between calculations and measurements indicated that not only neutrons but also high-energy gamma rays (>5 MeV) triggered the detectors because of photoneutrons produced in the detector materials. In the lateral direction, the contribution of photoneutrons to both detectors was negligible. Downstream of the LINAC, where high-energy photons were abundant, photoneutrons contributed approximately 6% of the response of the conventional neutron detector; however, almost 50% of the registered counts of the extended-range neutron detector were from photoneutrons because of the presence of the detector rather than the effect of the neutron field. Dose readings delivered by extended-range neutron detectors should be interpreted cautiously when used in radiation fields containing a mixture of neutrons and high-energy gamma rays

  14. Transmission line matching simulation for 350 MHz RF driver for 400 KeV (deuterium) RFQ based 14 MeV neutron source

    International Nuclear Information System (INIS)

    Sharma, Sonal; Pande, Manjiri; Handu, V.K.

    2009-01-01

    A 60 KW, 350 MHz tetrode based high power RF system is being developed for 400 KeV RFQ based 14 MeV neutron generator in Bhabha Atomic Research Centre to study physics of coupled neutron sources and subcritical assembly. This RF system requires a 2.5 kW RF driver which is being designed by using tetrode TH-393. At such high frequency i.e. 350 MHz, lumped components are not practically useful due to radiation losses. Therefore, techniques such as coaxial line with stub tuning are preferred, which minimizes these losses. Simulation of two such stub tuning based matched coaxial lines at the input and output of the tube has been done by using CST studio. CST STUDIO is a special tool for the 3D EM simulation of high frequency components

  15. Magnetic insulation of secondary electrons in plasma source ion implantation

    International Nuclear Information System (INIS)

    Rej, D.J.; Wood, B.P.; Faehl, R.J.; Fleischmann, H.H.

    1993-01-01

    The uncontrolled loss of accelerated secondary electrons in plasma source ion implantation (PSII) can significantly reduce system efficiency and poses a potential x-ray hazard. This loss might be reduced by a magnetic field applied near the workpiece. The concept of magnetically-insulated PSII is proposed, in which secondary electrons are trapped to form a virtual cathode layer near the workpiece surface where the local electric field is essentially eliminated. Subsequent electrons that are emitted can then be reabsorbed by the workpiece. Estimates of anomalous electron transport from microinstabilities are made. Insight into the process is gained with multi-dimensional particle-in-cell simulations

  16. 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 work, we demonstrate the real-time outputs derived by the end user from the REleASE using both SOHO/EPHIN and ACE/EPAM. We further, show a user friendly illustration of the outputs that make use of a "traffic light" to monitor the different warning stages: quiet, warning, alert offering a simple guidance to the end users. Finally, the capabilities offered by this new system, accessing both the pictorial and textural outputs REleASE are being presented. This work has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 637324.

  17. Simulation of the scattering in a thorium foil of 0.15-2.3 MeV electrons and positrons

    International Nuclear Information System (INIS)

    Bargholtz, Chr.; Holmberg, L.; Liljequist, D.; Tegner, P.E.

    1993-01-01

    Studies of the scattering in thorium of electrons emitted in the decay of 90 Sr, involving measurements of the coincidence spectra of electrons and positrons in the energy region 210-420 keV in search for anomalies, have previously been reported. In the analysis of the experimental results, computer simulations of the scattering and energy loss of the electrons and positrons were used. The present report describes the models and assumptions used in this simulation and the comparison with experimentally determined spectra

  18. Effect of 6 MeV electrons on luminescence properties of Y{sub 2}O{sub 3}:Tb{sup 3+} nanophosphors

    Energy Technology Data Exchange (ETDEWEB)

    Sunitha, D.V., E-mail: sunithaprasad8@gmail.com [School of Physics, Reva University, Yelahanka, Bangalore 560064 (India); Nagabhushana, H. [Prof. C.N.R. Rao Centre for Advanced Materials Research, Tumkur University, Tumkur 572103 (India); Hareesh, K., E-mail: appi.2907@gmail.com [Department of Physics, Savitribai Phule Pune University, Pune 411007 (India); Bhoraskar, V.N. [Department of Physics, Savitribai Phule Pune University, Pune 411007 (India); Dhole, S.D., E-mail: sanjay@physics.unipune.ac.in [Department of Physics, Savitribai Phule Pune University, Pune 411007 (India)

    2016-09-15

    Y{sub 2}O{sub 3}:Tb{sup 3+} nanophosphors were synthesized by solution combustion technique and irradiated with 6 MeV energetic electrons in the fluence range 2–10×10{sup 13} e{sup −}cm{sup −2}. Powder X-ray diffraction (PXRD) patterns confirm cubic phase of Y{sub 2}O{sub 3}. The crystallite size was estimated using Scherrer method and was found to be in the order of ~39 nm. SEM micrographs revealed the formation of non-uniform spherical shaped particles for higher electron fluence. Photoluminescence spectra (PL) of pristine and Tb{sup 3+} doped Y{sub 2}O{sub 3} were recorded in the fluence range 2–10×10{sup 13} e{sup −}cm{sup −2}. PL intensity was found to increase up to 4×10{sup 13} e{sup −}cm{sup −2} and thereafter it decreases with further increase in electron fluence. This may be attributed to lattice disorder produced by dense electronic excitation under electron irradiation. The characteristic emission peaks of Tb{sup 3+} were observed at ~ 484–490 nm ({sup 5}D{sub 4}→{sup 7}F{sub 6}), 548 nm ({sup 5}D{sub 4}→{sup 7}F{sub 5}) and 587 nm ({sup 5}D{sub 4}→{sup 7}F{sub 4}) at excited wavelength 397 nm. Two TL glow peaks were recorded in both pristine and electron irradiated samples indicate that two types of traps were created. The color co-ordinate values (x, y) were located in the green region of the CIE diagram suggests that electron irradiated Y{sub 2}O{sub 3}:Tb{sup 3+} phosphor could be used in white LEDs.

  19. Dosimetry of the energy of the electrons beam and virtual distance of the source of a lineal accelerator

    International Nuclear Information System (INIS)

    Gonzales, A.; Garcia, B.; Ramirez, J.; Marquina, J.

    2014-08-01

    The objectives of this work were to characterize, to gauge the energy of a electrons beam of 12 MeV and to find the virtual distance of the source for a lineal accelerator Trilogy-Varian. For the characterization, calibration and to find the virtual distance of the source of a lineal accelerator Trilogy-Varian, a water phantom was used (cylindrical Cuba 3-D) of Sun-Nuclear. The following values were found: R 50.ion = 4, 95 g/cm 2 , R 50 = 5, 04 g/cm 2 , Z ref = 2,92 g/cm 2 , Z max = 2, 60 g/cm 2 . In the calibration was found D W,Q (Z max ) = 1, 0015 c Gy/Um. In the profile In-plane was measured a symmetry and flatness of 1, 9% and 1, 6% respectively. In the profile Cross-plane a symmetry was measured and flatness of 1, 9% and 1, 3% respectively. The virtual distance regarding the source was of DFS (virtual) =105,81 cm. The electrons beam of 12 MeV was characterized and gauged satisfactorily, were carried out the In-plane and Cross-plane profiles, obtaining all the parameters inside the acceptance limit. The virtual distance of the source was of 105,81 cm. (Author)

  20. Studies on effective atomic numbers for photon energy absorption and electron density of some narcotic drugs in the energy range 1 keV-20 MeV

    Science.gov (United States)

    Gounhalli, Shivraj G.; Shantappa, Anil; Hanagodimath, S. M.

    2013-04-01

    Effective atomic numbers for photon energy absorption ZPEA,eff, photon interaction ZPI,eff and for electron density Nel, have been calculated by a direct method in the photon-energy region from 1 keV to 20 MeV for narcotic drugs, such as Heroin (H), Cocaine (CO), Caffeine (CA), Tetrahydrocannabinol (THC), Cannabinol (CBD), Tetrahydrocannabivarin (THCV). The ZPEA,eff, ZPI,eff and Nel values have been found to change with energy and composition of the narcotic drugs. The energy dependence ZPEA,eff, ZPI,eff and Nel is shown graphically. The maximum difference between the values of ZPEA,eff, and ZPI,eff occurs at 30 keV and the significant difference of 2 to 33% for the energy region 5-100 keV for all drugs. The reason for these differences is discussed.

  1. Neutron interrogation of actinides with a 17 MeV electron accelerator and first results from photon and neutron interrogation non-simultaneous measurements combination

    Energy Technology Data Exchange (ETDEWEB)

    Sari, A., E-mail: adrien.sari@cea.fr [CEA, LIST, Laboratoire Capteurs et Architectures Electroniques, 91191 Gif-sur-Yvette Cedex (France); Carrel, F.; Lainé, F. [CEA, LIST, Laboratoire Capteurs et Architectures Electroniques, 91191 Gif-sur-Yvette Cedex (France); Lyoussi, A. [CEA, DEN, 13108 Saint-Paul-Lez-Durance Cedex (France)

    2013-10-01

    In this article, we demonstrate the feasibility of neutron interrogation using the conversion target of a 17 MeV linear electron accelerator as a neutron generator. Signals from prompt neutrons, delayed neutrons, and delayed gamma-rays, emitted by both uranium and plutonium samples were analyzed. First results from photon and neutron interrogation non-simultaneous measurements combination are also reported in this paper. Feasibility of this technique is shown in the frame of the measurement of uranium enrichment. The latter was carried out by combining detection of prompt neutrons from thermal fission and delayed neutrons from photofission, and by combining delayed gamma-rays from thermal fission and delayed gamma-rays from photofission.

  2. Possible explanation of the electron positron anomaly at 17 MeV in {sup 8}Be transitions through a light pseudoscalar

    Energy Technology Data Exchange (ETDEWEB)

    Ellwanger, Ulrich [Laboratoire de Physique Théorique, UMR 8627, CNRS,Université de Paris-Sud, University Paris-Saclay,Campus d’Orsay, 91405 Orsay (France); School of Physics and Astronomy, University of Southampton,Highfield, Southampton SO17 1BJ (United Kingdom); Moretti, Stefano [School of Physics and Astronomy, University of Southampton,Highfield, Southampton SO17 1BJ (United Kingdom)

    2016-11-08

    We estimate the values of Yukawa couplings of a light pseudoscalar A with a mass of about 17 MeV, which would explain the {sup 8}Be 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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Yeon, Yeong Heum [Sungkyunkwan University, WCU Department of Energy Science, 2066, Seobu-ro, Jangan-gu, Suwon-si (Korea, Republic of); Ghergherehchi, Mitra; Kim, Sang Bum; Jun, Woo Jung [Sungkyunkwan University, School of Information & Communication Engineering, 2066, Seobu-ro, Jangan-gu, Suwon-si (Korea, Republic of); Lee, Jong Chul; Mohamed Gad, Khaled Mohamed [Sungkyunkwan University, WCU Department of Energy Science, 2066, Seobu-ro, Jangan-gu, Suwon-si (Korea, Republic of); Namgoong, Ho [Sungkyunkwan University, School of Information & Communication Engineering, 2066, Seobu-ro, Jangan-gu, Suwon-si (Korea, Republic of); Chai, Jong Seo, E-mail: jschai@skku.edu [Sungkyunkwan University, School of Information & Communication Engineering, 2066, Seobu-ro, Jangan-gu, Suwon-si (Korea, Republic of)

    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.

  4. 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

  5. Enhanced ECR ion source performance with an electron gun

    International Nuclear Information System (INIS)

    Xie, Z.; Lyneis, C.M.; Lam, R.S.; Lundgren, S.A.

    1991-01-01

    An electron gun for the advanced electron cyclotron resonance (AECR) source has been developed to increase the production of high charge state ions. The AECR source, which operates at 14 GHz, is being developed for the 88-in. cyclotron at Lawrence Berkeley Laboratory. The electron gun injects 10 to 150 eV electrons into the plasma chamber of the AECR. With the electron gun the AECR has produced at 10 kV extraction voltage 131 e μA of O 7+ , 13 e μA of O 8+ , 17 e μA of Ar 14+ , 2.2 e μA of Kr 25+ , 1 e μA of Xe 31+ , and 0.2 e μA of Bi 38+ . The AECR was also tested as a single stage source with a coating of SiO 2 on the plasma chamber walls. This significantly improved its performance compared to no coating, but direct injection of electrons with the electron gun produced the best results

  6. Introduction to ECR [electron cyclotron resonance] sources in electrostatic machines

    International Nuclear Information System (INIS)

    Olsen, D.K.

    1989-01-01

    Electron Cyclotron Resonance (ECR) ion source technology has developed rapidly since the original pioneering work of R. Geller and his group at Grenoble in the early 1970s. These ion sources are capable of producing intense beams of highly charged positive ions and are used extensively for cyclotron injection, linac injection, and atomic physics research. In this paper, the possible use of ECR heavy-ion sources in the terminals of electrostatic machines is discussed. The basic concepts of ECR sources are reviewed in the next section using the ORNL source as a model. The possible advantages of ECR sources over conventional negative ion injection and foil stripping are discussed in Section III. The last section describes the possible installation of an ECR source in a large machine such as the HHIRF 25-MV Pelletron. 6 refs., 4 figs., 1 tab

  7. Compact synchrotron radiation source

    International Nuclear Information System (INIS)

    Liu, N.; Wang, T.; Tian, J.; Lin, Y.; Chen, S.; He, W.; Hu, Y.; Li, Q.

    1985-01-01

    A compact 800 MeV synchrotron radiation source is discussed. The storage ring has a circumference of 30.3 m, two 90 degree and four 45 degree bending magnet sections, two long straight sections and four short straight sections. The radius of the bending magnet is 2.224m. The critical wave length is 24A. The injector is a 15 Mev Microtron Electrons are accelerated from 15 Mev to 800 Mev by ramping the field of the ring. The expected stored current will be around 100 ma

  8. Proceedings of the Japan-U.S. workshop P-119 on 14 MeV neutron source for material R and D based on plasma devices

    International Nuclear Information System (INIS)

    Miyahara, A.; Coensgen, F.H.

    1988-06-01

    In addition to the development of an adequate means to contain reacting D-T plasma in the range of 100 million deg K, the successful development of nuclear fusion as an energy source requires the development of new long-lived, low-activation materials. These new fusion reactor materials should not become radioactive when subjected to intense neutron irradiation for a long period. If the induced radioactivity cannot be entirely avoided, it must be short-lived and at relatively low level. The material development is already in progress using existing fission irradiation facilities and low level 14 MeV neutron sources. But the final selection and qualification of fusion reactor materials will require end of life testing. The neutron irradiation facilities for this purpose, the approximation of D-T neutron spectrum and the design of fusion material irradiation test (FMIT) are discussed. The workshop P-119 was organized to promote the development of plasma-based neutron sources. The presentation of each concept included its physics basis, neutron field characteristics, the required research and development and their schedules, and the rough estimation of the costs for development, construction and operation. (K.I.)

  9. 0 degree binary encounter electron production in 30-MeV Oq++H2, He, O2, Ne, and Ar collisions

    International Nuclear Information System (INIS)

    Zouros, T.J.; Wong, K.L.; Grabbe, S.; Hidmi, H.I.; Richard, P.; Montenegro, E.C.; Sanders, J.M.; Liao, C.; Hagmann, S.; Bhalla, C.P.

    1996-01-01

    Double-differential cross sections (DDCS close-quote s) for the production of binary encounter electrons (BEE close-quote s) were measured for collisions of 30-MeV O q+ projectiles with H 2 , He, O 2 , Ne, and Ar targets with q=4 endash 8 and an electron ejection angle of θ=0 degree with respect to the beam direction. Particular interest focused on (a) the evaluation of the contributions of the different electron subshells of the multielectron targets, O 2 , Ne, and Ar; (b) the study of the well-known enhancement of the BEE DDCS close-quote s with decreasing projectile charge-state q; here this dependence was tested for higher collision energies and new targets; (c) the study of the dependence of the BEE peak energy on the particular target and projectile charge state. Results were analyzed in terms of the impulse approximation, in which target electrons in the projectile frame undergo 180 degree elastic scattering in the field of the projectile ion. The electron scattering calculations were performed in a partial-wave treatment using the Hartree-Fock model. Good agreement with the data was found for the H 2 and He targets, while for the multielectron targets O 2 , Ne, and Ar only electrons whose velocity was lower than the projectile velocity needed to be included for good agreement. All measured BEE DDCS close-quote s were found to increase with decreasing projectile charge state, in agreement with other recent BEE results. The BEE peak energies were found to be independent of the projectile charge state for all targets utilized. copyright 1996 The American Physical Society

  10. Investigation of radiative corrections in the scattering at 180 deg. of 240 MeV positrons on atomic electrons

    International Nuclear Information System (INIS)

    Poux, J.P.

    1972-06-01

    In this research thesis, after a recall of processes of elastic scattering of positrons on electrons (kinematics and cross section), and of involved radiative corrections, the author describes the experimental installation (positron beam, ionization chamber, targets, spectrometer, electronic logics associated with the counter telescope) which has been used to measure the differential cross section of recoil electrons, and the methods which have been used. In a third part, the author reports the calculation of corrections and the obtained spectra. In the next part, the author reports the interpretation of results and their comparison with the experiment performed by Browman, Grossetete and Yount. The author shows that both experiments are complementary to each other, and are in agreement with the calculation performed by Yennie, Hearn and Kuo

  11. Miniature electron bombardment evaporation source: evaporation rate measurement

    International Nuclear Information System (INIS)

    Nehasil, V.; Masek, K.; Matolin, V.; Moreau, O.

    1997-01-01

    Miniature electron beam evaporation sources which operate on the principle of vaporization of source material, in the form of a tip, by electron bombardment are produced by several companies specialized in UHV equipment. These sources are used primarily for materials that are normally difficult to deposit due to their high evaporation temperature. They are appropriate for special applications such as heteroepitaxial thin film growth requiring a very low and well controlled deposition rate. A simple and easily applicable method of evaporation rate control is proposed. The method is based on the measurement of ion current produced by electron bombardment of evaporated atoms. The absolute evaporation flux values were measured by means of the Bayard-Alpert ion gauge, which enabled the ion current vs evaporation flux calibration curves to be plotted. (author). 1 tab., 4 figs., 6 refs

  12. L-MM Auger electron production in 0.3-1.6 MeV Kr-Kr collisions

    International Nuclear Information System (INIS)

    DeGroot, P.; Zarcone, M.J.; Kessel, Q.C.; Connecticut Univ., Storrs

    1987-01-01

    Relative total cross sections for Kr L-Auger electron emission are presented and compared with the corresponding X-ray data of Woerlee and Shanker and coworkers. These data sets all show the same incident ion energy dependence, indicating a constant fluorescence yield for the collision conditions under consideration. These data are also in agreement with a rotational coupling calculation by shanker and coworkers that was carried out within the framework of the one-electron molecular orbital model of Fano and Lichten. (orig.)

  13. 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

  14. Development and characterization of electron sources for diffraction applications

    International Nuclear Information System (INIS)

    Casandruc, Albert

    2015-12-01

    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

  15. Interaction of electron neutrinos with 56Fe in the LSD for Eνe≤50 MeV

    International Nuclear Information System (INIS)

    Gaponov, Yu.V.; Semenov, S.V.; Ryazhskaya, O.G.

    2004-01-01

    The neutrino pulses, detected by LSD (liquid scintillator detector) on February 23, 1987, are analyzed on the base of two-stage model of supernova explosion. The number of events due to the electron neutrino interaction with 56 Fe in the LSD is calculated. The obtained results is in a agreement with experimental data [ru

  16. CGR MeV program for water and liquid sludges treatment with high-energy electron beams. Pt. 1

    International Nuclear Information System (INIS)

    Gallien, C.L.; Icre, P.; Levaillant, C.; Montiel, A.

    1976-01-01

    Research on the application of high-energy electron beams treatment to water and liquid sludges is described. Topics discussed include limitations of conventional methods of water treatment, dosimetry, biological assays with Pleurodeles waltlii, radioactivity measurement, chemical and bacteriological analysis. (author)

  17. Performance of a GaAs electron source

    International Nuclear Information System (INIS)

    Calabrese, R.; Ciullo, G.; Della Mea, G.; Egeni, G.P.; Guidi, V.; Lamanna, G.; Lenisa, P.; Maciga, B.; Rigato, V.; Rudello, V.; Tecchio, L.; Yang, B.; Zandolin, S.

    1994-01-01

    We discuss the performance improvement of a GaAs electron source. High quantum yield (14%) and constant current extraction (1 mA for more than four weeks) are achieved after a little initial decay. These parameters meet the requirements for application of the GaAs photocathode as a source for electron cooling devices. We also present the preliminary results of a surface analysis experiment, carried out by means of the RBS technique to check the hypothesis of cesium evaporation from the surface when the photocathode is in operation. (orig.)

  18. Pleiades: A Sub-picosecond Tunable X-ray Source at the LLNL Electron Linac

    International Nuclear Information System (INIS)

    Slaughter, Dennis; Springer, Paul; Le Sage, Greg; Crane, John; Ditmire, Todd; Cowan, Tom; Anderson, Scott G.; Rosenzweig, James B.

    2002-01-01

    The use of ultra fast 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, femto-second-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 photo-injector, 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 (∼ 10 Hz). (authors)

  19. On the influence of high energy (250MeV) electron irradiation on the structure and properties of aluminium

    International Nuclear Information System (INIS)

    Gindin, I.A.; Neklyudov, I.M.; Okovit, V.S.; Starolat, M.P.; Dyatlov, V.P.

    1974-01-01

    The results of studies on the amplitude dependence of internal friction and structural changes in technically pure aluminium in the initial state and after irradiation with high-energy electrons are presented. Three stages are observed in the internal friction curves from the amplitude of the waves. If the values of the internal friction remain the same, irradiation considerably widens the amplitude-independent region and shifts the second and third regions toward the high-amplitude direction at first. Starting with the Granate-Luke model, changes in the length of the free dislocation segments in irradiated aluminium were determined. Electron microscope studies showed the presence of numerous radiation defects and changes in the configuration with dislocation lines in irradiated aluminum

  20. 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.

  1. Generation, control, and transport of a 19-MeV, 700-kA pulsed electron beam

    International Nuclear Information System (INIS)

    Sanford, T.W.L.; Halbleib, J.A.; Poukey, J.W.; Welch, D.R.; Mock, R.C.; Skogmo, P.J.; Mikkelson, K.A.

    1993-01-01

    The authors show experimentally and theoretically that the generation of the 13-TW Hermes III electron beam can be accurately monitored, and that the beam can be accurately directed onto a high-Z target to produce a wide variety of bremsstrahlung patterns. This control allows the study of radiation effects induced by gamma rays to be extended into new parameter regimes. Finally, they show that the beam can be stably transported in low-pressure gas cells

  2. Secondary electron radiation from different targets exposed to photons with energy 0.1 to 3 MeV

    International Nuclear Information System (INIS)

    Akkerman, A.F.; Botvin, V.A.; Chernov, G.Ya.

    1982-01-01

    Differential and integral yields of secondary electrons from different targets bombarded by monoenergetic photon beams are calculated using the Monte Carlo method. The results are compared to experimental data and values calculated by other authors. The discovered 20 to 30% decrease of calculated backward yields according to experimental data for heavy elements is explained by the limited applicability of Sauter's formula for the description of photoelectron angular distribution. (author)

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

    International Nuclear Information System (INIS)

    Cobut, V.; 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

  4. Electron and photon spread contributions to the radiological penumbra for small monoenergetic x-ray beam (<=2 MeV)

    Science.gov (United States)

    Pignol, Jean-Philippe; Keller, Brian M.

    2009-05-01

    Our team has previously published that submegavoltage photons could significantly improve the radiological penumbra for small size radiation fields. The present work uses Monte Carlo simulation to evaluate the contributions of secondary electrons and photon scatter to the penumbra region for various field sizes (5, 10, 20, and 40 mm in diameters) and for various monoenergetic photon beams (200, 400, 600, 800, 1000, and 2000 keV, and a standard 6 MV beam), minimizing geometrical and transmission penumbra. For field sizes less than 2 cm in diameter, photon scatter is negligible such that the secondary electrons are the main contributor to the radiological penumbra. Reducing the photon beam energy to the submegavoltage range reduces the range of secondary electrons and eventually improves the beam boundary sharpness. Provided that the geometrical penumbra and patient immobilization system are optimized, submegavoltage photon beams with effective photon energies in the 300 to 600 keV range, present significant advantages for multiple beam stereotactic irradiations of tumors less than 2 cm in diameter.

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

    Energy Technology Data Exchange (ETDEWEB)

    Garg, Akash Deep, E-mail: akash-deep@rrcat.gov.in [Beam Diagnostics Section (BDS), Indus Operations, Beam Dynamics and Diagnostics Division (IOBDD), Raja Ramanna Centre for Advanced Technology, Indore 452 013, M.P. (India); Homi Bhabha National Institute (HBNI) at Raja Ramanna Centre for Advanced Technology, Indore (India); Yadav, S.; Kumar, Mukesh; Shrivastava, B.B.; Karnewar, A.K.; Ojha, A.; Puntambekar, T.A. [Beam Diagnostics Section (BDS), Indus Operations, Beam Dynamics and Diagnostics Division (IOBDD), Raja Ramanna Centre for Advanced Technology, Indore 452 013, M.P. (India)

    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.

  6. Foreign electronic information sources about environment in the Internet

    International Nuclear Information System (INIS)

    Svrsek, L.

    2005-01-01

    This presentation deals with external electronic information sources (e-sources) i. e. about data bases which are formed no by users or their institutes. Data bases are compiled by producers of data which are publishing in different forms and offerer it for users by different form. In the first part of contribution e-sources are described at the first generally. In the second part, some most significant data bases about environment in on-line medium of Internet, are described in detail

  7. Electron backstream to the source plasma region in an ion source

    International Nuclear Information System (INIS)

    Ohara, Y.; Akiba, M.; Arakawa, Y.; Okumura, Y.; Sakuraba, J.

    1980-01-01

    The flux of backstream electrons to the source plasma region increases significantly with the acceleration voltage of an ion beam, so that the back plate in the arc chamber should be broken for quasi-dc operation. The flux of backstream electrons is estimated at the acceleration voltage of 50--100 kV for a proton beam with the aid of ion beam simulation code. The power flux of backstream electrons is up to about 7% of the total beam output at the acceleration voltage of 75 kV. It is pointed out that the conventional ion sources such as the duoPIGatron or the bucket source which use a magnetic field for source plasma production are not suitable for quasi-dc and high-energy ion sources, because the surface heat flux of the back plate is increased by the focusing of backstream electrons and the removal of it is quite difficult. A new ion source which has an electron beam dump in the arc chamber is proposed

  8. 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

    International Nuclear Information System (INIS)

    Azadegan, B.

    2007-01-01

    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 μm. 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 μm 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 μm thick

  9. 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

  10. Field emission from a new type of electron source

    International Nuclear Information System (INIS)

    Mousa, M.S.

    1987-01-01

    A new type of field emission electron source has been developed. In this paper, the construction, characteristics and behaviour of tungsten micropoint emitters coated with a sub-micron layer of hydrocarbon using a TEM with poor ( ∼ 1 0 -3 torr) vacuum conditions are described. The hydrocarbon coating has been verified using the X-Ray energy dispersive analysis technique of a SEM. The technical capabilities and potential of the new type of electron source are compared with those of other comparable composite micropoint field emitters and other types of electron sources currently in use. The emission properties presented here include I-V characteristics, emission images and electron energy spectra of this type of composite micropoint emitters. The effect on the behaviour and characteristics of baking the coated emitters at temperatures ranging between 140 0 C and 350 0 C is also studied. The behaviour of the emitter has been interpreted in terms of a field-induced hot-electron emission mechanism associated with metal-insulator-vacuum (M-I-V) regime

  11. Emerging Pattern in Utilizing Electronic Information Sources by ...

    African Journals Online (AJOL)

    This is a detailed comparative analysis of electronic information sources (EIS) utilized by pharmacy lecturers in South-South universities in Nigeria. The purpose of this study is to analyze the extent to which EIS are utilized among pharmacy lecturers in South-South Nigeria. The aim is to explore the emerging pattern of ...

  12. Ion source for thinning of specimen in transmission electron microscopy

    International Nuclear Information System (INIS)

    Hammer, K.; Rothe, R.

    1983-01-01

    Thinning of specimen for transmission electron microscopy is carried out by means of sputtering. Construction, design, and operation parameters of an ion source are presented. Because the plasma is produced by means of hollow cathode glow discharges, no special focusing system is used

  13. Utilization Status of Electronic Information Sources (EIS) for HIV ...

    African Journals Online (AJOL)

    Tesfa

    HIV/AIDS Care and Treatment in Specialized Teaching Hospitals of. Ethiopia, 2016. Senait Samuel Bramo. 1. , Tesfamichael Alaro Agago. 2*. OPEN ACCESS. Citation: Senait Samuel Bramo,. Tesfamichael Alaro Agago. Utilization. Status of Electronic Information Sources. (EIS) for HIV/AIDS Care and Treatment.

  14. 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...... the two studies and that from literature to provide initial evidence-based heuristics for EDS selection....

  15. Management of the installation of a 10 MeV, 50 kW electron-beam irradiator

    International Nuclear Information System (INIS)

    Lawrence, C.B.; Armstrong, L.; Drewell, N.H.; McKeown, J.; Scott, L.; O'Brien, D.; Svendsen, E.

    1995-08-01

    An IMPELA-10/50 electron-beam irradiator has been installed by AECL Accelerators in Iotron Industries' service centre near Vancouver. Construction of the facility, installation of the accelerator and conveyor, and commissioning to the full rated power of 50 kW were completed in 12 months. Iotron began commercial irradiation immediately and the first continuous operation achieved 250 hours of production in 12 days. The engineering, production and project management organizations and activities to complete the on-schedule installation and commissioning are reviewed. (author). 3 refs., 2 tabs., 1 fig

  16. Optimization of the microwave coupler and microwave measurements of the microtron cavity for 20 MeV pre-injector microtron for INDUS-I SRS

    International Nuclear Information System (INIS)

    Wanmode, Y.D.; Shrivastava, Purushottam; Hannurkar, P.R.

    2003-01-01

    A 20 MeV microtron was developed indigenously by CAT for pre-injection of 20 MeV electrons to the 450 MeV/700 MeV Booster Synchrotron for INDUS-I and INDUS-II Synchrotron Radiation Sources. The injector microtron uses a high Q microwave cavity for acceleration of electrons. The microwave power is fed to the microtron cavity through an iris type coupler whose dimensions are optimized for the coupling factor and resonant frequency for the accelerator. The present paper gives the procedure details for coupling factor optimization, tuning of the resonant frequency and results achieved. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

    Willems van Beveren, L. H., E-mail: laurensw@unimelb.edu.au; Bowers, H.; Ganesan, K.; Johnson, B. C.; McCallum, J. C.; Prawer, S. [School of Physics, University of Melbourne, Parkville, Victoria 3010 (Australia); Liu, R. [SIMS Facility, Office of the Deputy-Vice Chancellor (Research and Development) Western Sydney University, Locked Bag 1797, Penrith, New South Wales 2751 (Australia)

    2016-06-14

    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.

  18. Microstructural parameters in 8 MeV Electron irradiated Bombyx mori silk fibers by wide-angle X-ray scattering studies (WAXS)

    International Nuclear Information System (INIS)

    Halabhavi, Sangappa

    2009-01-01

    The present work looks into the microstructural modification in Bombyx mori silk fibers, induced by electron irradiation. The irradiation process was performed in air at room temperature by use of 8 MeV electron accelerators at different doses: 0, 25, 50, 75 and 100 kGy respectively. Irradiation of polymer can be used to crosslink or degrade the desired component or to fixate the polymer morphology. The changes in microstructural parameters in these natural polymer fibers have been studied using wide angle X-ray scattering (WAXS) method. The crystal imperfection parameters such as crystallite size , lattice strain (g in %) and enthalpy (a * ) have been determined by line profile analysis (LPA) using Fourier method of Warren. Exponential, Lognormal and Reinhold functions for the column length distributions have been used for the determination of these parameters. The goodness of the fit and the consistency of these results suggest that the exponential distribution gives much better results, even though lognormal distribution has been widely used to estimate the similar stacking faults in metal oxide compounds. (author)

  19. Design and construction of a novel compact doubly achromatic asymmetric 2700 magnet system for 25 MeV therapy electron accelerator

    International Nuclear Information System (INIS)

    Hutcheon, R.M.; Hodge, S.B.

    1980-09-01

    A modern cancer therapy electron accelerator unit must satisfy many design constraints, one of which is the isocentric height above floor level. Usually 130 cm is considered the maximum height at which a nurse can work with a patient. The advent of higher energy machines has increasingly made this more difficult to achieve, as higher magnetic fields are required in the magnet that directs the beam onto the patient. A new 270 degree doubly-achromatic magnet configuration has been developed which minimizes the isocentre height for a given maximum energy and maximum magnetic field. The system is an asymmetric two-magnet configuration, with zero field index, equal fields and a bend of greater than 180 degrees in the first magnet. It is compact, easy to manufacture and relatively insensitive to assembly tolerances. Energy defining slits are easily incorporated in the design and can readily be radiation shielded. Input and output beam matching and steering is easily accomplished with a compact input quadrupole doublet and small steering windings. This report details the design and bench testing of a head magnet for a 25 MeV electron accelerator with +- 10 percent energy acceptance. The output beam requirement is < 3 mm diameter with < +- 17 mrad angular divergence. (auth)

  20. Detection of Materials Used for Improvised Explosive Devices Employing D-T (14 MeV) Neutron Source

    International Nuclear Information System (INIS)

    Shyam, Anurag; Sharma, Surender Kumar; Das, Basanta

    2010-01-01

    There is an increased use of improvised explosive devices (IED), especially for human targets. One of the substances used in these devices is ammonium nitrate. Since this IED substance also contains elements - hydrogen (H), carbon (C), nitrogen (N), oxygen (O). The elemental density (of H, C, O, and N) and elemental density ratio (C/O, N/O, H/N etc) can be used to differentiate it from other substances. Neutrons based techniques are one of the methods for non-destructive these elemental characterization. For our experiments we are using two sealed neutron tubes. First tubes can produce 10 8 (maximum) D-T neutrons in ∼0.8 μs pulse and 100 (maximum) pulses can be generated per second. Second tube can produce (maximum) 10 10 D-T neutrons/s. The neutron output can be pulsed. Pulses of 1.5 μs duration and pulse repetition rate of 10 Hz to 10 kHz can be obtained. D-T neutrons pulses are impinged on ammonium nitrate samples (0.5 to 1.5 kg) and resultant gamma rays (prompt and due to activation) are recorded using sodium iodide (NaI) and bismuth germanium orthosilicate (BGO) scintillation detectors. To facilitate recording of high count rate a 2 GS/s high speed digitizer with large on board memory and high transfer rate has been used (instead of conventional multi channel analyzer). Preliminary results and analysis will be presented at the conference. To further refine the technique we are also developing a D-T neutron generator with associated particle detection facility. For this system we have already developed a penning ion source and a 140 kV battery operated SMPS. (author)

  1. 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......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 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...

  2. Electron diodes and cavity design for the new 4-MeV injector of the recirculating linear accelerator (RLA)

    International Nuclear Information System (INIS)

    Mazarakis, M.G.; Smith, D.L.; Poukey, J.W.; Bennett, L.F.; Olson, W.R.; Turman, B.N.

    1991-01-01

    The authors have designed and constructed four types of electron-beam diodes for the new 4-MV RLA injector: a non-immersed foilless diode, a magnetically immersed foilless diode, a foil diode and an ion-focused foilless diode, They are tailored to fit the new injector cavity. The design goals were to produce high quality 10-kA to 20-kA electron beams with a β perpendicular smaller than 0.2 and a beam radius of the order of 2 cm. These beams will be matched to the RLA IFR channel so β perpendicular must be equal to or smaller than the square root of the ratio of the beam current versus Alfven current for f e = 1. A reentrant anode geometry was selected for the injector cavity design, because it offers substantial savings on the required amount of feromagnetic cores. The inner radius of the outside shell, now only 30 cm, would have been twice as large (60 cm) if a coaxial non-reentrant geometry had been adopted. The shape of the anode and cathode electrodes were carefully selected to minimize the electric field stresses. The field stresses on the inner surface of the outer shell do not exceed 200 kV/cm

  3. Electron cyclotron resonance plasmas and electron cyclotron resonance ion sources: Physics and technology (invited)

    International Nuclear Information System (INIS)

    Girard, A.; Hitz, D.; Melin, G.; Serebrennikov, K.

    2004-01-01

    Electron cyclotron resonance (ECR) ion sources are scientific instruments particularly useful for physics: they are extensively used in atomic, nuclear, and high energy physics, for the production of multicharged beams. Moreover, these sources are also of fundamental interest for plasma physics, because of the very particular properties of the ECR plasma. This article describes the state of the art on the physics of the ECR plasma related to multiply charged ion sources. In Sec. I, we describe the general aspects of ECR ion sources. Physics related to the electrons is presented in Sec. II: we discuss there the problems of heating and confinement. In Sec. III, the problem of ion production and confinement is presented. A numerical code is presented, and some particular and important effects, specific to ECR ion sources, are shown in Sec. IV. Eventually, in Sec. V, technological aspects of ECR are presented and different types of sources are shown

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

    International Nuclear Information System (INIS)

    Pafundi, Deanna; Lee, Choonsik; Bolch, Wesley; Rajon, Didier; Jokisch, Derek

    2010-01-01

    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.

  5. 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.

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

    CERN Multimedia

    CERN PhotoLab

    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. High peak power THz source for ultrafast electron diffraction

    Directory of Open Access Journals (Sweden)

    Shengguang Liu

    2018-01-01

    Full Text Available Terahertz (THz science and technology have already become the research highlight at present. In this paper, we put forward a device setup to carry out ultrafast fundamental research. A photocathode RF gun generates electron bunches with ∼MeV energy, ∼ps bunch width and about 25pC charge. The electron bunches inject the designed wiggler, the coherent radiation at THz spectrum emits from these bunches and increases rapidly until the saturation at ∼MW within a short wiggler. THz pulses can be used as pump to stimulate an ultra-short excitation in some kind of sample. Those electron bunches out of wiggler can be handled into bunches with ∼1pC change, small beam spot and energy spread to be probe. Because the pump and probe comes from the same electron source, synchronization between pump and probe is inherent. The whole facility can be compacted on a tabletop.

  8. Simulation of Coulomb interaction effects in electron sources

    International Nuclear Information System (INIS)

    Rouse, John; Zhu Xieqing; Liu Haoning; Munro, Eric

    2011-01-01

    Over many years, we have developed electron source simulation software that has been used widely in the electron optics community to aid the development of rotationally symmetric electron and ion guns. The simulation includes the modelling of cathode emission and the effects of volumetric space charge. In the present paper we describe the existing software and explain how we have extended this software to include the effects of discrete Coulomb interactions between the electrons as they travel from the cathode surface to the exit of the gun. In the paper, we will describe the numerical models we have employed, the techniques we have used to maximize the speed of the Coulomb force computation and present several illustrative examples of cases analyzed using the new software, including thermal field emitters, LaB 6 guns and flat dispenser-type cathodes.

  9. A ns-pulsed high-current electron beam source

    International Nuclear Information System (INIS)

    Guan, Gexin; Li, Youzhi; Pan, Yuli

    1988-01-01

    The behaviour of a pulse electron beam source which is composed of a gun and pulse system depends on not only the time characteristics of the gun and the pulser, but also their combination. This point become apparent if effects of the electron tansit-time between electrodes are studied. A ferrite transmission line (FTL) pulser is used as a grid driver in this source. It has advantages of providing fast risetime, large peak power output and good loading characteristics. It is these advantages of the pulser that compensates the absence of some technological conditions of manufacturing gun and makes the source better. Our testing showed that the cooperation of both the gun and the pulser produced peak currents in the range of 1 to 9 amps with widths of 2 to 2.5 ns (FWHM) at cathode-to-anode potential of 60 to 82 kv, while the grid drives are about in the range of 1 to 3 kv. In addition, the results of the testing instructed that effects of electron transit-time cannot be ignored when the pulses with widths of several nanoseconds are used as a grid drive. Based on the results, electron transit-time effects on the design of the gun and the beam performances are briefly descussed in this paper. (author)

  10. 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.

  11. Application of Electron Accelerators in Conjunction with Microwave Sources in Medical Studies

    International Nuclear Information System (INIS)

    Martin, D.; Craciun, G.; Manaila, E.; Ighigeanu, D.; Margaritescu, I.; Chirita, D.; Neagu, M.

    2009-01-01

    Electron beams (EB) are presently used, in addition to the routine conventional radiotherapy techniques, for cancer specialized therapies (intensity modulated radiation therapy [1] and total body electron irradiation [2]), the irradiation of blood and blood components, vaccine preparation, and other. Microwaves (MW) are presently used for therapeutic applications in cardiology, urology, surgery, ophthalmology, cancer therapy, and others, and for diagnostic applications such as cancer detection, organ imaging, and more [3]. The reported data show that low dose-all body irradiation with ionizing as well as with nonionizing irradiation may enhance the tumoricidal effects of radiation or chemotherapy, overcome acquired drug resistance and can stimulate certain components of the immune system that may aid in destroying cancer cells. These data suggested that application of low-dose total body EB + MW irradiation in conjunction with chemotherapy could contribute by novel effects to the cancer therapies. In view of this argument two specifically designed radiation exposure devices (REDs) were carried out for separate, successive and simultaneous irradiation with EB of 6.23 MeV and MW of 2.45 GHz in vivo (RED-vivo) and in vitro (RED-vitro) for the following medical studies: 1) The effects of low-dose EB + MW total body irradiation without/with drugs administration on the C57 BL/6 mice bearing malignant melanoma (MM); 2) The effects of separate and simultaneous MW and EB irradiation on MM cells culture without/with drugs incubation and on human blood components (proteins and cells) irradiated in samples of integral blood from healthy donors and from donors with MM. Both REDs consist of the following units: 1) An accelerated EB source: ALIN-10 electron linear accelerator of 6.23 MeV and adjustable absorbed dose rate from 0.002 Gy s-1 up to 70 Gy s-1 (built in the NILPRP, Bucharest, Romania); 2) A special designed exposure chamber that permits inside separate, successive or

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

    CERN Multimedia

    CERN PhotoLab

    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.

  13. Studies on color-center formation in glass utilizing measurements made during 1 to 3 MeV electron irradiation

    International Nuclear Information System (INIS)

    Swyler, K.J.; Levy, P.W.

    1976-01-01

    The coloring of NBS 710 glass has been studied using a new facility for making optical absorption measurements during and after electron irradiation. The induced absorption contains three Gaussian shaped bands. The color center growth curves contain two saturating exponential and one linear components. After irradiation the coloring decays and can be described by three decreasing exponentials. At room temperature both the coloring curve plateau and coloring rate increase with increasing dose rate. Coloring measurements made at a fixed dose rate but at increasing temperature indicate: (1) the coloring curve plateau decreases with increasing temperature and coloring has not been observed at 400 0 C; (2) the plateau is reached more rapidly as the temperature increases; (3) the decay occurring after irradiation cannot be described by Arrhenius kinetics. At each temperature the coloring can be explained by simple kinetics. The temperature dependence of the decay can be explained if it is assumed that the thermal untrapping is controlled by a distribution of activation energies

  14. Deep-level defects introduced by 1 MeV electron radiation in AlInGaP for multijunction space solar cells

    International Nuclear Information System (INIS)

    Lee, H.S.; Yamaguchi, M.; Ekins-Daukes, N. J.; Khan, A.; Takamoto, T.; Agui, T.; Kamimura, K.; Kaneiwa, M.; Imaizumi, M.; Ohshima, T.; Itoh, H.

    2005-01-01

    Presented in this paper are 1 MeV electron irradiation effects on wide-band-gap (1.97 eV) (Al 0.08 Ga 0.92 ) 0.52 In 0.48 P diodes and solar cells. The carrier removal rate estimated in p-AlInGaP with electron fluence is about 1 cm -1 , which is lower than that in InP and GaAs. From high-temperature deep-level transient spectroscopy measurements, a deep-level defect center such as majority-carrier (hole) trap H2 (E ν +0.90±0.05 eV) was observed. The changes in carrier concentrations (Δp) and trap densities as a function of electron fluence were compared, and as a result the total introduction rate, 0.39 cm -1 , of majority-carrier trap centers (H1 and H2) is different from the carrier removal rate, 1 cm -1 , in p-AlInGaP. From the minority-carrier injection annealing (100 mA/cm 2 ), the annealing activation energy of H2 defect is ΔE=0.60 eV, which is likely to be associated with a vacancy-phosphorus Frenkel pair (V p -P i ). The recovery of defect concentration and carrier concentration in the irradiated p-AlInGaP by injection relates that a deep-level defect H2 acts as a recombination center as well as compensator center

  15. A combined source of electron bunches and microwave power

    International Nuclear Information System (INIS)

    Xie, J.L.; Wang, F.Y.; Yang, X.P.; Shen, B.; Gu, W.; Zhang, L.W.

    2003-01-01

    In this article, the possibility of using a high power klystron amplifier simultaneously as a microwave power source as usual and an electron bunches source by extracting the spent beam with a magnet and also as an oscillator by feedback is investigated. The purpose of this study is to demonstrate the feasibility of constructing a very compact electron linear accelerator or for other applications of electron bunches. The feasibility of the idea was first examined by computer simulation of the electron motion in a 5 MW klystron and the characteristics of the klystron spent beam. Experimental study was then carried out by installing a radio frequency cavity and a Faraday cage in sequence at the exit end of a bending magnet located at the top of the klystron collector. The energy and current of the chopped spent electron beam can then be measured. By properly choosing the feedback circuit elements, the frequency stability of the klystron in oscillator mode was proved to be good enough for linac operation. According to the results presented in this article, it is evident that an extremely compact linac for research and education with better affordability can be constructed to promote the applications of linacs

  16. 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)

  17. 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)

  18. Developing electron beam bunching technology for improving light sources

    International Nuclear Information System (INIS)

    Carlsten, B.E.; Chan, K.C.D.; Feldman, D.W.

    1997-01-01

    This is the final report of a three-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The goal of this project was to develop a new electron bunch compression technology, experimentally demonstrate subpicosecond compression of bunches with charges on the order of 1 nC, and to theoretically investigate fundamental limitations to electron bunch compression. All of these goals were achieved, and in addition, the compression system built for this project was used to generate 22 nm light in a plasma-radiator light source

  19. Electron temperature effects for an ion beam source

    International Nuclear Information System (INIS)

    Uramoto, Joshin.

    1979-05-01

    A hydrogen high temperature plasma up to 200 eV is produced by acceleration of electrons in a hot hollow cathode discharge and is used as an ion beam source. Then, two characteristics are observed: A rate of the atomic ion (H + ) number increases above 70%. A perveance of the ion beam increases above 30 times compared with that of a cold plasma, while a floating potential of an ion acceleration electrode approaches an ion acceleration potential (- 500 V) according as an increment of the electron temperature. Moreover, a neutralized ion beam can be produced by only the negative floating electrode without an external power supply. (author)

  20. Simulation of equivalent dose due to accidental electron beam loss in Indus-1 and Indus-2 synchrotron radiation sources using FLUKA code

    International Nuclear Information System (INIS)

    Sahani, P.K.; Dev, Vipin; Singh, Gurnam; Haridas, G.; Thakkar, K.K.; Sarkar, P.K.; Sharma, D.N.

    2008-01-01

    Indus-1 and Indus-2 are two Synchrotron radiation sources at Raja Ramanna Centre for Advanced Technology (RRCAT), India. Stored electron energy in Indus-1 and Indus-2 are 450MeV and 2.5GeV respectively. During operation of storage ring, accidental electron beam loss may occur in addition to normal beam losses. The Bremsstrahlung radiation produced due to the beam losses creates a major radiation hazard in these high energy electron accelerators. FLUKA, the Monte Carlo radiation transport code is used to simulate the accidental beam loss. The simulation was carried out to estimate the equivalent dose likely to be received by a trapped person closer to the storage ring. Depth dose profile in water phantom for 450MeV and 2.5GeV electron beam is generated, from which percentage energy absorbed in 30cm water phantom (analogous to human body) is calculated. The simulation showed the percentage energy deposition in the phantom is about 19% for 450MeV electron and 4.3% for 2.5GeV electron. The dose build up factor in 30cm water phantom for 450MeV and 2.5GeV electron beam are found to be 1.85 and 2.94 respectively. Based on the depth dose profile, dose equivalent index of 0.026Sv and 1.08Sv are likely to be received by the trapped person near the storage ring in Indus-1 and Indus-2 respectively. (author)

  1. 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.

  2. The effect of 15 MeV electrons at different irradiation depth on the growth of HeLa cells

    International Nuclear Information System (INIS)

    Helmerking, B.

    1975-01-01

    The effect of fast electrons at relative depth doses of 100% and 30% with energy doses of 100 to 400 rad and a dose rate of 200 rad/min on HeLa cells was analyzed. For the evaluation of the irradiation effect, the cell count of irradiated cultures compared with the cell count of not irradiated cultures 16 d after irradiation. The determination of the cell numbers and thus the determination of the counting multiplication rate of the cells was done by isolated cell nuclei with a counter tube and a counter chamber. Irradiation of the cells took place in the plateau phase of the growth curve. After irradiation with a relative depth dose of 100% as well as of 30%, a decrease of the cell number of the cultures can be observed on the 16th day. After irradiation with 200 rad in 100%-depth a survival rate of 72% is found and in 30% depth a survival rate of 60%. At 300 rad the values are 44% for 100% depth, and 30% for 30% depth. For 400 rad the survival rate is 11% at 100% depth and 5% at 30% depth. On the basis of the above-mentioned values the survival rate after irradiation with 30% relative depth dose at the energy doses 200, 300 and 400 rad is increasingly less in comparison with the irradiation with 100% relative depth dose. In the range of 200 to 400 the RBW of the 100% depth in comparison with the 30% depth is constant with a value of 0.88 +- 0.03. The determination of the cell count of a culture by counting isolated nuclei, which is a new method of assessing an irradiation effect is discussed. The significance of this new criterion is compared with the known method of colony counting. The results are compared with results of other works using method of colony counting, and are discussed. (orig./MG) [de

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

    International Nuclear Information System (INIS)

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

    2016-01-01

    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  ∼10 7 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. (paper)

  4. 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.

  5. Microstructured liquid metal electron and ion sources (MILMES/MILMIS)

    Energy Technology Data Exchange (ETDEWEB)

    Mitterauer, J [Technische Universitaet Wien (Austria). Institut fuer Allgemeine Elektrotechnik und Elektronik

    1997-12-31

    Ion or electron beams can be emitted from liquid metal wetted needles, or from capillaries or slits into which the liquid metal is allowed to flow. Large-area liquid metal field emission sources have been proposed recently, using either two-dimensional, regular arrays of cones or capillaries, or even a substrate with an intrinsically microstructured surface covered by a liquid metal film. This latter concept has been realized in a pilot experiment by in situ wicking and wetting of a porous sintered metal disc. Microstructured liquid metal ion or electron sources are capable of operating in a pulsed mode at a current level which is orders of magnitude above that for steady-state operation. (author). 3 figs., 10 refs.

  6. Crystallographic data processing for free-electron laser sources

    International Nuclear Information System (INIS)

    White, Thomas A.; Barty, Anton; Stellato, Francesco; Holton, James M.; Kirian, Richard A.; Zatsepin, Nadia A.; Chapman, Henry N.

    2013-01-01

    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. 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.

  8. 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.

  9. 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.

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

    International Nuclear Information System (INIS)

    Mukai, Masaki; Kim, Judy S.; Omoto, Kazuya; Sawada, Hidetaka; Kimura, Atsushi; Ikeda, Akihiro; Zhou, Jun; Kaneyama, Toshikatsu; Young, Neil P.; Warner, Jamie H.; Nellist, Peter D.; Kirkland, Angus I.

    2014-01-01

    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

  11. Temperature-dependent photoluminescence analysis of 1-MeV electron irradiation-induced nonradiative recombination centers in GaAs/Ge space solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Tiancheng, Yi; Pengfei, Xiao; Yong, Zheng; Juan, Tang; Rong, Wang, E-mail: wangr@bnu.edu.cn

    2016-03-01

    The effects of irradiation of 1-MeV electrons on p{sup +}–n GaAs/Ge solar cells have been investigated by temperature-dependent photoluminescence (PL) measurements in the temperature range of 10–290 K. The temperature dependence of the PL peak energy agrees well with the Varnish relation, and the thermal quenching of the total integrated PL intensity is well explained by the thermal quenching theory. Meanwhile, the thermal quenching of temperature-dependent PL confirmed that there are two nonradiative recombination centers in the solar cells, and the thermal activation energies of these centers are determined by Arrhenius plots of the total integrated PL intensity. Furthermore, the nonradiative recombination center, as a primary defect, is identified as the H3 hole trap located at E{sub v} + 0.71 eV at room temperature and the H2 hole trap located at E{sub v} + 0.41 eV in the temperature range of 100–200 K, by comparing the thermal activation and ionization energies of the defects.

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

    Energy Technology Data Exchange (ETDEWEB)

    Soltani, Z., E-mail: zhr_soltani@yahoo.com [Health Physics and Radiation Dosimetry Research Laboratory, Department of Energy Engineering and Physics, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of); Ziaie, F. [Radiation Application Research School, Nuclear Science & Technology Research Institute, Tehran (Iran, Islamic Republic of); Ghaffari, M. [Polymer Group, Golestan University, Golestan (Iran, Islamic Republic of); Beigzadeh, A.M. [Radiation Application Research School, Nuclear Science & Technology Research Institute, Tehran (Iran, Islamic Republic of)

    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 10 MeV electron beam at doses of 75 to 250 kGy. 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.

  13. Effect of MgSO4 on expression of NSE and S-100 in rats brain tissue irradiated by 6 MeV electron beam

    International Nuclear Information System (INIS)

    Zhou Juying; Wang Lili; Yu Zhiying; Qin Songbing; Xu Xiaoting; Li Li; Tu Yu

    2007-01-01

    Objective: To explore the protection of magnesium sulfate (MgSO 4 ) on radiation-induced acute brain injuries. Methods: Thirty six mature Sprague-Dawley rats were randomly divided into 3 groups: blank control group, experimental control group and experimental administered group. The whole brain of SD rats of experimental control group and experimental-therapeutic group were irradiated with a dose of 20 Gy using 6 MeV electron beam. Magnesium sulfate was injected intraperitoneally into the rats of experimental-therapeutic group before and after irradiation for five times. The brain tissue were taken on days 1, 7, 14 and 30 after irradiation. Immunohistochemical method was used to detect the expressions of NSE and S-100 in brain tissue. All data were processed statistically with One-ANOVA analysis. Results: The expressions of NSE and S-100 after whole brain irradiation were time-dependent. Compared with blank control group, the expression of NSE in brains of experimental control group decreased significantly (P 4 can inhibit the expression of S-100, but induce the expression of NSE on radiation-induced acute brain injury. MgSO 4 has a protective effect on radiation-induced acute brain injury. (authors)

  14. 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)

  15. Enhanced confinement in electron cyclotron resonance ion source plasma.

    Science.gov (United States)

    Schachter, L; Stiebing, K E; Dobrescu, S

    2010-02-01

    Power loss by plasma-wall interactions may become a limitation for the performance of ECR and fusion plasma devices. Based on our research to optimize the performance of electron cyclotron resonance ion source (ECRIS) devices by the use of metal-dielectric (MD) structures, the development of the method presented here, allows to significantly improve the confinement of plasma electrons and hence to reduce losses. Dedicated measurements were performed at the Frankfurt 14 GHz ECRIS using argon and helium as working gas and high temperature resistive material for the MD structures. The analyzed charge state distributions and bremsstrahlung radiation spectra (corrected for background) also clearly verify the anticipated increase in the plasma-electron density and hence demonstrate the advantage by the MD-method.

  16. Electron Cloud Mitigation in the Spallation Neutron Source Ring

    International Nuclear Information System (INIS)

    Wei, J.; Blaskiewicz, Michael; Brodowski, J.; Cameron, P.; Davino, Daniele; Fedotov, A.; He, P.; Hseuh, H.; Lee, Y.Y.; Ludewig, H.; Meng, W.; Raparia, D.; Tuozzolo, J.; Zhang, S.Y.; Catalan-Lasheras, N.; Macek, R.J.; Furman, Miguel A.; Aleksandrov, A.; Cousineau, S.; Danilov, V.; Henderson, S.

    2008-01-01

    The Spallation Neutron Source (SNS) accumulator ring is designed to accumulate, via H - injection, protons of 2 MW beam power at 1 GeV kinetic energy at a repetition rate of 60 Hz [1]. At such beam intensity, electron-cloud is expected to be one of the intensity-limiting mechanisms that complicate ring operations. This paper summarizes mitigation strategy adopted in the design, both in suppressing electron-cloud formation and in enhancing Landau damping, including tapered magnetic field and monitoring system for the collection of stripped electrons at injection, TiN coated beam chamber for suppression of the secondary yield, clearing electrodes dedicated for the injection region and parasitic on BPMs around the ring, solenoid windings in the collimation region, and planning of vacuum systems for beam scrubbing upon operation

  17. Electron-cloud mitigation in the spallation neutron source ring

    International Nuclear Information System (INIS)

    Wei, J.; Blaskiewicz, M.; Brodowski, J.; Cameron, P.; Davino, D.; Fedotov, A.; He, P.; Hseuh, H.; Lee, Y.Y.; Meng, W.; Raparia, D.; Tuozzolo, J.; Zhang, S.Y.; Danilov, V.; Henderson, S.; Furman, M.; Pivi, M.; Macek, R.

    2003-01-01

    The Spallation Neutron Source (SNS) accumulator ring is designed to accumulate, via H- injection, protons of 2 MW beam power at 1 GeV kinetic energy at a repetition rate of 60 Hz [1]. At such beam intensity, electron cloud is expected to be one of the intensity-limiting mechanisms that complicate ring operations. This paper summarizes mitigation strategy adopted in the design, both in suppressing electron-cloud formation and in enhancing Landau damping, including tapered magnetic field and monitoring system for the collection of stripped electrons at injection, TiN coated beam chamber for suppression of the secondary yield, clearing electrodes dedicated for the injection region and parasitic on BPMs around the ring, solenoid windings in the collimation region, and planning of vacuum systems for beam scrubbing upon operation

  18. Characteristics of a cold cathode electron source combined with secondary electron emission in a FED

    International Nuclear Information System (INIS)

    Lei Wei; Zhang Xiaobing; Zhou Xuedong; Zhu Zuoya; Lou Chaogang; Zhao Hongping

    2005-01-01

    In electron beam devices, the voltage applied to the cathode (w.r.t. grid voltage) provides the initial energy for the electrons. Based on the type of electron emission, the electron sources are (mainly) classified into thermionic cathodes and cold cathodes. The power consumption of a cold cathode is smaller than that of a thermionic cathode. The delay time of the electron emission from a cold cathode following the voltage rise is also smaller. In cathode ray tubes, field emission display (=FED) panels and other devices, the electron current emitted from the cathode needs to be modulated. Since the strong electric field, which is required to extract electrons from the cold cathode, accelerates the electrons to a high velocity near the gate electrode, the required voltage swing for the current modulation is also high. The design of the driving circuit becomes quite difficult and expensive for a high driving voltage. In this paper, an insulator plate with holes is placed in front of a cold cathode. When the primary electrons hit the surface of the insulator tunnels, secondary electrons are generated. In this paper, the characteristics of the secondary electrons emitted from the gate structure are studied. Because the energies of the secondary electrons are smaller than that of the primary electron, the driving voltage for the current modulation is decreased by the introduction of the insulator tunnels, resulting in an improved energy uniformity of the electron beam. Triode structures with inclined insulator tunnels and with double insulator plates are also fabricated and lead to further improvements in the energy uniformity. The improved energy uniformity predicted by the simulation calculations is demonstrated by the improved brightness uniformity in the screen display images

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

    CERN Document Server

    Gushenets, V I

    2001-01-01

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

  20. 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.