Energy Technology Data Exchange (ETDEWEB)

Characteristics of lead-zirconate-titanate (PZT) elements were studied by directly irradiating them with a 400 MeV/n Xe beam. The elements were sensitive to 10{sup 4} Xe ions and their output amplitudes were proportional to the beam intensity. An ensemble of those output amplitudes displayed a Bragg-curve-like response towards the range of 400 MeV/n Xe ion. We discuss the potential of PZT elements as a radiation detector and their application to high-intensity and high-energy detectors. (author)

International Nuclear Information System (INIS)

Full text: Research reactors have been playing a multi dimensional role in areas of nuclear fuel cycle programme, radio-isotope productions, neutron beam research etc. To ensure an efficient, smooth and safe operation of a nuclear research reactor, many reactor physics evaluations are required on routine basis. As part of reactor core management the important activities are maintaining core reactivity status, core power distribution, xenon estimations, safety evaluation of in-pile irradiation samples and experimental assemblies and assessment of nuclear safety in fuel handling/storage. In-pile irradiation requires a prior estimation of the reactivity load due to the sample, heating rate and the activity developed in it during irradiation. For the safety of the personnel handling irradiated samples the dose rate at the surface of shielded flask housing the irradiated sample should be less than 200 mR/Hr. Therefore, a proper shielding and ...

Energy Technology Data Exchange (ETDEWEB)

The article is devoted to results of fine time structure of particle losses in Tevatron with use of fast beam loss monitors (BLM) based on PIN-diodes. An ultimate goal of the new BLMs is to distinguish losses of protons and antiprotons from neighbor bunches with 132 ns bunch spacing in the Tevatron collider upgrade. The devices studied fit well to the goal as they can recognize even seven times closer - 18.9 ns - spaced bunches` losses in the Tevatron fixed target operation regime. We have measured main characteristics of the BLM as well as studied the proton losses over 10 decades of time scale - from dozen of minutes to dozen of nanoseconds. Power spectral density of the losses is compared with spectra of the proton beam motion.

International Nuclear Information System (INIS)

Noninvasive and simplified methods for estimating regional cerebral blood flow (CBF) and regional partition coefficient (#lambda#) using the inhalation of stable xenon (Xe"s) and computed tomographic (CT) scanning are described. Thirty percent Xe"s in 70% oxygen was inhaled for 240 seconds and exhaled for 160 seconds during serial CT scanning without denitrogenation in 26 patients with cerebrovascular diseases and four volunteer controls. During the investigation, the end-tidal Xe"s concentration was continuously monitored with a thermoconductivity analyzer to determine the build-up range (A value) and build-up rate constant (K value) of the artery by the curve fitting method. Calculated A and K values were corrected by the following formulae reported previously: for patients aged 0-20 years, A_e = 0.75A_a + 2.15, K_e = 0.67K_a + 0.69; 21-40 years, A_e = 0.56A_a + 3.24, K_e = 0.38K_a + 1.12; 41-60 years, A_e = 0.91A_a + 1.95, K_e = 0.38K_a + ...

Energy Technology Data Exchange (ETDEWEB)

Scintillation light in liquid xenon excited by 100 MeV/n Al ions was detected with a home-made silicon photodiode. The diameter of the photodiode was 2 inch. The effective quantum efficiency was observed to be 22% for the wavelength of liquid xenon scintillation light (170 nm), while the effective quantum efficiency for 5.486 MeV alpha-particle excitation was 44%. An energy resolution of 0.5% rms was achieved for the energy deposition of 2.5 GeV in liquid xenon using a fast preamplifier ({approx equal} 20 ns). (orig.).

Energy Technology Data Exchange (ETDEWEB)

Responsibility for the operation and maintenance of the bulk of the 132 kV cable network in England and Wales was transferred from the CEGB to the area boards in the 1970s. Norweb has successfully dealt with the increase in work using in-house expertise exclusively.

Energy Technology Data Exchange (ETDEWEB)

An RF plasma sputter type heavy negative ion source, which can deliver mA-class negative ion beams (12.1 mA, 1.6 mA and 2.3 mA for Cu{sup -}, C{sup -} and C{sub 2}{sup -} currents, respectively) in dc-mode operation, has been developed. In ion source, a dense plasma of 10{sup 11} cm{sup -3} order was generated in the xenon gas pressure of 10{sup -3}-10{sup -2} Pa with an rf (13.56 MHz) power of 200 - 300 W by using an RF coil, and a relatively large sputtering target of 42 mm in diameter was used. As for intense negative ion beams of silicon or boron which are important dopants for semiconductor fabrication, negative ion extraction properties of the negative ion source was investigated. The extracted total negative ion currents of 4.4 mA for a silicon target and 2.8 mA for a LaB{sub 6} target were obtained after electrons were eliminated by magnetic field near the extraction hole. From results of mass-analysis, it was found ...

CERN Document Server

High pressure xenon ionization chamber detectors are possible alternatives to traditional thallium doped sodium iodide (NaI(Tl)) and hyperpure germanium as gamma spectrometers in certain applications. Xenon detectors incorporating a Frisch grid exhibit energy resolutions comparable to cadmium/zinc/telluride (CZT) (e.g. 2% (at) 662keV) but with far greater sensitive volumes. The Frisch grid reduces the position dependence of the anode pulse risetimes, but it also increases the detector vibration sensitivity, anode capacitance, voltage requirements and mechanical complexity. We have been investigating the possibility of eliminating the grid electrode in high-pressure xenon detectors and preserving the high energy resolution using electronic risetime compensation methods. A two-electrode cylindrical high pressure xenon gamma detector coupled to time-to-amplitude conversion electronics was used to ...

Energy Technology Data Exchange (ETDEWEB)

Lifetimes have been measured in the {pi}h{sub 9/2} (yrast) and {pi}i{sub 13/2} (excited) bands in the nuclei {sup 181}Ir and {sup 187}Au using the Recoil Distance Method (RDM). The results clearly indicate that the {pi}i{sub 13/2} band exhibits an increased deformation over the {pi}h{sub 9/2} band, in keeping with the premise that the delayed crossing in this band is due to enhanced quadrupole deformation. (author). 3 refs, 1 fig, 2 tab.

International Nuclear Information System (INIS)

English 2008 p. 132-133 Turkey Nishonov, Sh. Khujaev, S.

British Library Electronic Table of Contents (United Kingdom)

We have studied the nature of continuum emitted in the visible spectral range from a noncontracted positive column of discharge in a cesium vapor-xenon mixture at a pressure of 45 Torr and at a degree of ionization below 3 ? 10?6. The main contribution to the continuous emission under such conditions is due to electron-xenon atom bremsstrahlung. The intensity of emission has been experimentally and theoretically studied as a function of the electric field strength and electron density in the positive column. It is established that an increase in the visible emission intensity with the electric field strength is related to an increase in the number of hot electrons in plasma.

International Nuclear Information System (INIS)

A noninvasive method is described for estimating local cerebral blood flow (LCBF) and local partition coefficients by means of computed tomographic scanning during inhalation of 30% stable xenon gas in oxygen. Time-dependent xenon concentrations in arterial blood and brain tissue during the wash-in and washout phases are used to calculate partition coefficients and LCBF values by means of a least-squares curve-fitting analysis. Control values for partition coefficient and LCBF obtained from control subjects with minor head trauma in the chronic stage were compatible with those in several past reports, and reproducibility was satisfactory. The theoretic grounds underlying this new method of curve-fitting analysis are discussed.

Energy Technology Data Exchange (ETDEWEB)

A brief comparative review of possible mercury free fluorescent lighting technologies is presented, including rare-gas positive column discharges, molecular discharges, and dielectric barrier discharges. Detailed experimental results on xenon positive column discharges will then be considered. In order to judge whether xenon-based discharges are a viable UV source it is necessary to measure the radiant emittance (power per unit area) for the vacuum ultraviolet (VUV) resonance xenon emission at 147 nm. Two techniques to determine the VUV radiant emittance have been developed and applied to xenon discharges. One method combines the measured resonance level density using absorption spectroscopy and a calculation of the trapped decay rate for the resonance radiation to arrive at the radiant emittance at 147 nm. A second method utilizes a direct measurement of the radiance (power per unit area per unit solid ...

UK PubMed Central (United Kingdom)

To determine who resists sexual assault and what happens, data were examined from a probability sample of 3,132 adult community residents of Los Angeles, California. Seventy-five per cent of the respondents...Full Text Available

UK PubMed Central (United Kingdom)

Sheep choroid plexus cells infected with visna virus produce intracytoplasmic viral ribonucleoprotein complexes with sedimentation values of 120S to 200S and buoyant densities of 1.29 to 1.32 g/cm3....Full Text Available

Energy Technology Data Exchange (ETDEWEB)

Monitoring for xenon radionuclides which are produced in a nuclear detonation can provide a strong deterrent to the violation of a Comprehensive nuclear Test Ban Treaty (CTBT). There are 18 known radioactive xenon isotopes produced in nuclear fission with half-lives ranging from less than one second to 11.9 days. However, only four of these remain in significant amounts more than a day after a detonation. In order for radioxenon monitoring to be practical, it was necessary to develop an automated measurement system which could operate unattended for periods of months, measure the entire spectrum of radioxenons, and provide hundreds of times better sensitivities than current laboratory procedures. This capability was developed at the US Department of Energy`s Pacific Northwest National Laboratory based on rapid separation of atmospheric xenon coupled with a unique high sensitivity measurement device for the radioxenons. A ...

Science.gov (United States)

Based on a collisional-radiative model, an atomic-kinetic calculation of the gains on the 41.8-nm transitions of Pd-like xenon was performed for the plasma produced due to the interaction of a femtosecond laser pulse with gaseous xenon. The gains g(z,{tau}) averaged over the spatial and temporal coordinates were compared with the known gains which had been measured experimentally in Xe{sup 8+}. The amplification was shown to occur under the conditions of ionisation of the working ions, and the time of output radiation saturation depends on the time of Xe{sup 8+} transformation to higher-ionised ions. Our theoretical investigation enables determining the optimal pump parameters, at which the product of the gain g by the active medium length L is about 20, which exceeds the experimental gL value. (active media)

International Nuclear Information System (INIS)

We have observed EUV spectra from the Large Helical Device (LHD) at the National Institute for Fusion Science (NIFS). We measured spectra of impurity ions; carbon, iron, xenon, tin and tungsten ions. In some cases, the plasma evolution was stable and a steady discharge was obtained, but sometimes the plasma underwent radiation collapse and rapid cooling. For carbon and iron spectra, we studied plasma diagnostics by intensity ratios of spectral lines. For other spectra of higher Z element, xenon, tin and tungsten, we studied mainly on line identifications comparing with theoretical calculations and experimental data. Related atomic data for these researches will be also discussed. (author)

CERN Document Server

The Rayleigh scattering length has been calculated for rare-gas liquids in the ultraviolet for the frequencies at which they luminesce. The calculations are based on the measured dielectric constants in the gas phase, except in the case of xenon for which measurements are available in the liquid. The scattering length mayplace constraints on the design of some large-scale detectors, using uv luminescence, being proposed to observe solar neutrinos and dark matter. Rayleigh scattering in mixtures of rare-gas mixtures is also discussed.

International Nuclear Information System (INIS)

The Comprehensive Nuclear-Test-Ban-Treaty (CTBT), which was opened for signature in 1996, bans all nuclear explosions in all environments. Republic of Korea has been working to monitor compliance with CTBT by deterring and detecting any nuclear explosions conducted anywhere on Earth. For the verification of CTBT, several techniques are implemented. Radionuclide monitoring is of particular importance since it is the only method which can provide absolute assurance that a nuclear detonation has occurred

Energy Technology Data Exchange (ETDEWEB)

This paper describes a method for preparing the sample handling and inlet system of a mass spectrometer for analysis of a subsequent sample following analysis of a previous sample comprising the flushing of the system interior with supercritical CO{sub 2} and venting the interior. The method eliminates the effect of system ``memory`` on the subsequent analysis, especially following persistent samples such as xenon and krypton.

Energy Technology Data Exchange (ETDEWEB)

The g-factor of the 21/2/sup +/ state at 1921.9 keV in /sup 203/Pb has been measured through the time differential perturbed angular distribution technique in an external magnetic field B=2.028 T. The measured g-factor g=-0.063(2) indicates a predominantly three neutron hole configuration described by the wave function 0.68vertical strokei/sup -1//sub 13/2/f/sup -2//sub 5/2/>+-0.73vertical strokei/sup -1//sub 13/2/f/sup -1//sub 5/2/p/sup -1//sub 3/2/>.

International Nuclear Information System (INIS)

... Tsukuba, Ibaraki (Japan) 389 p. PARTICLE ACCELERATORS beam monitoring

Energy Technology Data Exchange (ETDEWEB)

No abstract prepared.

Energy Technology Data Exchange (ETDEWEB)

Non-invasive methods are described for estimating local cerebal blood flows (LCBF) and local partition coefficients (Llambda) during inhalation of 30 % stable xenon gas (Xe) in oxygen during CT scanning. After the denitrogenation with pure oxygen breathing, 30 % Xe is inhaled for four minutes to minimize subanesthetic effects with a rubber facemask and the delivery system of Xe. Local time-..delta.. Hounsfield units curve during the Xe wash-in and wash-out phase is utilized in order to calculate Llambda and LCBF using a least squares curve fitting analysis. Calculated Llambda and LCBF with the new method manifested reasonable distribution between the grey and white matters, and reproducibility was excellent in our study. Several case studies of patients with cerebral infarction are presented to demonstrate the characterization of Llambda and LCBF patterns in various tissues and theoretical grounds underlying the new method of curve fitting analysis are discussed.

Energy Technology Data Exchange (ETDEWEB)

Cesium recovery from the polluted layers in the 1/3 scale hydrogen negative ion source for LHD-NBI system has tested. It was found, that the cesium recovery can be produced by additional discharges as from the cesium layer, aged by tungsten and residual gas, so as from the cesium layers, polluted by an occasional water leak. The highest cesium recovery to NI production was produced by a xenon arc, while glow discharge and arcing in hydrogen were less effective. The mechanism of recovery is the ejection of cesium from the underlying enriched layer by the arc and its transport to the surface. (author)

Energy Technology Data Exchange (ETDEWEB)

Many monitoring activities require the collection of whole air samples over an extended time interval without loss or concentration of any atmospheric constituents. Described is the development and laboratory testing of a whole air sampler capable of collecting a 100 liter sample over a period of 0.63 days. The sampler has an empty weight of 7.79 kg and an overall size of 20.8-cm {times} 20.8-cm {times} 66.1-cm. The conceptual design for the development of smaller, higher-performance whole air samplers is also reported.

International Nuclear Information System (INIS)

In Pressurised heavy water reactors (PHWRs), neutron poison in the moderator is used to compensate the excess reactivity present in the core on different occasions such as xenon decay during synchronization just after poison out period or start ups from xenon free conditions. It is also used in secondary shutdown system (SDS-2), where required amount of neutron poison is injected directly into the moderator within 2.5 seconds. Further, it is also used for over poisoning the moderator to achieve the guaranteed shutdown state when the regular shutdown systems are taken for maintenance. Generally, two types of moderator poisons are used in power reactors to balance the reactivity of the core and they are boron and gadolinium. Gadolinium is used in the form of gadolinium nitrate (Gd(NO3)3.6H2O). The paper gives the details of estimation of reactivity coefficients of gadolinium for 540 MWe PHWR for different operating conditions. These neutron ...

Energy Technology Data Exchange (ETDEWEB)

Short communication.

Energy Technology Data Exchange (ETDEWEB)

Transport of negative ion beams through plasma is reviewed. The effect of space charge on beam stability and beam emittance is discussed. The approaches to the beam transport problem developed at Los Alamos, Berkeley, Oak Ridge and Culham Laboratory are intercompared. (AIP)

International Nuclear Information System (INIS)

High-spin states (I < or approx. 50(#Planck constant#/2#pi#)) of the odd-odd nucleus "1"7"0Ta have been investigated with the "1"2"4Sn("5"1V,5n) reaction. The resolving power of Gammasphere has allowed for the observation of eleven rotational bands (eight of which are new) and over 430 transitions (#approx#350 of which are new) in this nucleus. Many interband transitions have been observed such that the relative spins and excitation energies of the 11 bands have been established. This is an unusual circumstance in an odd-odd study. Configurations have been assigned to most of these bands based upon features such as alignment properties, band crossings, B(M1)/B(E2) ratios, and the additivity of Routhians. A systematic study of the frequency at which normal signature ordering occurs in the #pi#h_9_/_2#nu#i_1_3_/_2 band has been performed and it is found that its trend is opposite to that observed in the #pi#h_1_1_/_2#nu#i_1_3_/_2 bands. A ...

International Nuclear Information System (INIS)

The [402]5/2 bands in "1"7"7Ta which are ''identical'' to the neighboring even-even "1"7"6Hf groundstate band have been extended to higher angular momentum. These bands in the two nuclei are seen to diverge from each other in the region of the first i_1_3_/_2 neutron alignment. The lower observed crossing frequency for the [402]5/2 bands indicates a lower deformation for these bands compared to "1"7"6Hf. Extensions to the h_9_/_2 [541]1/2 yrast band are also reported. (orig.).

Science.gov (United States)

Experiments were conducted to study the condensation heat transfer characteristics of horizontal enhanced tubes. In the current experiment, six different enhanced tubes, including 26, 40 fpi low fin tubes and four three-dimensional-fin tubes, were tested. The working fluid used in the experiment was HCFC-22. Data were presented in the form of overall heat transfer coefficient at three working pressures, namely 1.32, 1.47 and 1.62 Mpa. In addition, the condensing heat transfer coefficients for the test tubes were obtained from the Wilson plot technique.

International Nuclear Information System (INIS)

Genes encoding mutants of the thymine photodimer repair enzyme from bacteriophage T4 (T4 endonuclease V) having an amino acid substitution (T127M, W128A, W128S, Y129A, K130L, Y131A, Y132A) were constructed by use of a previously obtained synthetic gene and expressed in Escherichia coli under the control of the E. coli tryptophan promoter. An in vitro assay of partially fractionated mutant proteins for glycosylase activity was performed with chemically synthesized substrates containing a thymine photodimer. T127M and K130L showed almost the same activity as the wild-type protein. Although W128S, Y131A, and Y132A were slightly active, W128A and Y129A lost activity. The results indicated that the aromatic amino acids around position 130 may be important for the glycosylase activity. Mutant T127M was purified, and the Km value was found to be of the same order as that of the wild type (10(-8) M). In vivo activities for all mutants were ...

International Nuclear Information System (INIS)

The design of the absorber blocks for internal and external dumping of the SPS proton beam is discussed. In addition, the external target stations for slow and fast extracted proton beams are described.

UK PubMed Central (United Kingdom)

Microplanar beam radiation therapy has been proposed to treat brain tumors by using a series of rapid exposures to an array of parallel x-ray beams, each beam having uniform microscopic thickness and...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

No abstract prepared.

International Nuclear Information System (INIS)

A simple beam-forming system is described for the electrostatic accelerator of the Scientific-Research Institute of Nuclear Physics of Moscow State University. The system allows the beam to be focused on targets at various distances for a conductor potential of from 1 to 4 MV and beam currents of up to 35 #mu# A.

British Library Electronic Table of Contents (United Kingdom)

In this study, wood samples were exposed to light irradiations (direct sunlight, xenon lamp, mercury vapour lamp) and thermal treatments were carried out in dry- and in humid conditions at 90degreeC. One part of the samples was covered by an aluminium plate during light irradiation. The samples under the aluminium plate also suffered considerable chemical changes, monitored by infrared technique and colour measurement. The sunlight produced greater colour change under the aluminium plate than the artificial light sources. During light irradiation, the carbonyl band having two maximum at 1700 and 1746cm-1 increased and the peak of the aromatic skeletal vibration arising from lignin (1510cm-1) decreased together with the guaiacyl vibrations at 1275cm-1. There was absorption decrease at 1174c...

Energy Technology Data Exchange (ETDEWEB)

We demonstrate that the nanoparticle formation during laser ablation of metals by short (of a few tens of ps) laser pulses strongly depends on the concentration of surrounding gas. While, at vacuum conditions, nanoparticle formation shows very ''sharp'' atomic force microscope images of aggregated clusters, following with clear appearance of plasmon resonance on the absorption spectra of deposited films, an addition of gas particles starts to decrease the probability of cluster formation. This process shows a threshold for both helium (33 torr) and xenon (12 torr) above which no surface plasmon resonance and correspondingly no observable nanoparticles on the deposited surfaces were detected. The destruction of nanoparticle formation was attributed to the negative influence of surrounding gas particles on ablated particles aggregation. (orig.)

Energy Technology Data Exchange (ETDEWEB)

Laser optical pumping can be used to produce polarized alkali atom beams or polarized alkali vapor targets. Polarized alkali atom beams can be converted into polarized alkali ion beams, and polarized alkali vapor targets can be used to produce polarized H/sup -/ or /sup 3/He/sup -/ ion beams. In this paper the authors discuss how the polarized alkali atom beams and polarized alkali vapor targets are used to produce polarized ion beams with emphasis on the production of polarized negative ion beams.

International Nuclear Information System (INIS)

Gallium liquid-metal ion sources that have been introduced in the late 1970s have allowed the development of a new class of micro- and nanofabrication tools collectively denominated as focused ion beam (FIB) machines. To investigate the potential of a helium beam in such a FIB instrument the authors have tested a room-temperature electron beam ion trap coupled with a high resolution FIB machine. In this letter they present their first results in target imaging using a helium beam with a resolution that allows to account for a beam diameter in the submicrometer range.

Energy Technology Data Exchange (ETDEWEB)

It is possible to produce energetic beams of radioactive nuclei, as secondary beams, from the heavy-particle compound accelerator called BEVALAC. These beams can be focused into experimental areas without significant contamination using suitable magnetic filters and proper beam-optics. Properly selected high-energy beams of radioactive nuclei (those which defay by positron emission) can provide a truly unique opportunity to evaluate the effectiveness of these beams in localizing the Bragg peak on a tumor volume - necessary in heavy-particle therapy. Preliminary data are presented here to demonstrate the possible use of these beams in radiotherapy treatment-planning verification.

International Nuclear Information System (INIS)

The electron beam ion source (EBIS) at Texas A and M University was constructed and is currently undergoing tests on the injection and transmission of the electron beam through the solenoid. Results of computer simulation of the electron beam are presented, as well as measurements of electron beam profiles using a pinhole beam analyzer.

Energy Technology Data Exchange (ETDEWEB)

Many nondestructive beam position monitors are known. However, these devices can not be used for DC particle beam diagnostics. We investigated a method of beam diagnostics applicable for the operative control of DC high power e-beam inside closed waveguide. A design of the detector for determination of{open_quote} center of mass {close_quote} position of DC particle beam was developed. It was shown that the monitor can be used as a nondestructive method for the beam position control in resonators. Magnetic field of the particle beam outside a resonator is used. The detector consists of the steel yokes and magnetic field sensors. The sensors measure magnetic fluxes in the steel yokes fixed outside the resonator. When the particle beam changes its position, these magnetic fluxes also change. Beam ...

Energy Technology Data Exchange (ETDEWEB)

A noninvasive, simplified method using inhalation of stable xenon (Xe{sup s}) and computed tomographic (CT) scanning to estimate regional cerebral blood flow (rCBF) and regional partition coefficient (r{lambda}) is described. Twenty-four patients with cerebrovascular occlusive disease and six volunteer controls inhaled 30% Xe{sup s} and 70% oxygen for 180 seconds and exhaled for 144 seconds during serial CT scanning without denitrogenation. The end-tidal Xe{sup s} concentration was continuously monitored with a thermoconductivity analyzer to determine the build-up range (A value) and build-up rate constant (K value) for arteries with the curve fitting method. The time-CT number (Hounsfield unit) curve for cerebral tissue during the Xe{sup s} washin and washout phases was used to calculate r{lambda} and rCBF using least squares curve fitting analysis. The resultant r{lambda} and rCBF map demonstrated a reliable distribution between the gray and white matter, and ...

International Nuclear Information System (INIS)

A new kind of e-beam bunching enabling the production of coherent spontaneous emission (CSE) is proposed and considered. It is shown that an e-beam in passing through an undulator will induce CSE along with incoherent spontaneous radiation on the same wavelength if the e-beam transverse velocity is modulated with a spatial period twice as long as the radiation wavelength. Such angular modulated beams can be regarded as alternatives to conventionally density modulated beams for CSE production. Requirements for e-beams are similar in both cases.

Energy Technology Data Exchange (ETDEWEB)

The NuMI proton beam at Fermilab currently delivers 120 GeV protons to the neutrino production target with design beam power capability to 400 kW. Upgrade capability to 700 kW is being prepared, with planning toward delivering 2.3 MW beam provided by the Project X accelerator upgrade plan. We report on the system of beam diagnostics and control used in operation of the NuMI beam. Also considered are the steps to provide a robust system for transport and targeting beam of 2 MW and beyond.

Energy Technology Data Exchange (ETDEWEB)

Aqueous solutions (mixed waste) generated from various LLNL operations, such as debris washing, sample preparation and analysis, and equipment maintenance and cleanout, were combined for storage in the B695 tank farm. Prior to combination the individual waste streams had different codes depending on the particular generating process and waste characteristics. The largest streams were CWC 132, 791, 134, 792. Several smaller waste streams were also included. This combined waste stream was treated at LLNL's waste treatment facility using a vacuum filtration and cool vapor evaporation process in preparation for discharge to sanitary sewer. Prior to discharge, the treated waste stream was sampled and the results were reviewed by LLNL's water monitoring specialists. The treated solution was discharged following confirmation that it met the discharge criteria. A major source, accounting for 50% for this waste stream, is metal machining, cutting and ...

British Library Electronic Table of Contents (United Kingdom)

Background/Purpose: Peripherally inserted central venous catheters (PICCs) are commonly used for neonatal vascular access. The aim of this study was to look at PICC line complication rates and possible predictors of PICC infection in a neonatal intensive care unit. Method: This was a prospective study of 226 neonates who had PICCs on our neonatal intensive care unit between January 2006 and June 2009. Complete data was available on 218 neonates who had 294 PICC lines. Criteria for catheter-related sepsis was positive blood cultures (peripheral/central) and/or a positive catheter tip culture after removal in the presence of a clinical suspicion of line sepsis. Results: Of 218 neonates, 132 (169 lines) were medical, and 86 (125 lines) were surgical. Our PICC line infection rate was 17 infect...

International Nuclear Information System (INIS)

In this work, we present results of a systematic study of optical properties of Er"3"+ ions in 6H SiC. The role of N-donors played in activation of photoluminescence (PL) of erbium at 1.5 #mu#m was investigated. We have confirmed that N-donors are necessary for activation of the Er PL on one hand, whereas on the other we present evidence that N-donors compete for excitation with Er centres. The high-resolution measurements of the Er"3"+ PL were performed aiming at determination of crystal field split levels of the "4I_1_5_/_2 ground and "4I_1_3_/_2 first excited multiplet of Er"3"+ ions. Careful analysis of temperature evolution of individual PL lines allowed proposing energy level schemes for the ground and first excited states.

British Library Electronic Table of Contents (United Kingdom)

The Quantou Formation recovered by CCSD-SK-Is borehole (China Cretaceous Continental Scientific Drilling-SongkeI-the south borehole) is 132.07 m long and the recovery of cores is 100%. The sequence and process of lithology-lithofacies and cyclostratigraphy are revealed by a detailed core description. Nine rock types and three kinds of sedimentary facies including meandering river, shallow lake, and delta front are recognized from the drilling core, there are ten sedimentary microfacies, which are point bar, natural levee, crevasse splay, crevasse channel, floodplain, flood lake, distributary mouth bar, interdistributary bay, mudstone of still water, and turbidite. The Quantou Formation represents seventy-six meter-scale cycles (sixth-order cycle), twenty-five fifth-order cycles, eight four...

International Nuclear Information System (INIS)

The effect of Kerr nonlinearity on an Airy beam is investigated by using the nonlinear Schroedinger equation. Based on the moments method, the evolution of the Airy beam width in the rms sense is analytically described. Numerical simulations indicate that the central parts of the major lobe of the Airy beam initially give rise to radial compression during propagation in a focusing medium, even though the rms beam width broadens. The partial collapse of the center parts of the major lobe of the beam appear below the threshold for a global collapse. The evolutions of the field distributions of the Airy beams are different during propagation in different Kerr media while the beams still travel along the parabolic trajectory just as the beam propagates in free space.

Energy Technology Data Exchange (ETDEWEB)

A discussion is presented of the 750-KeV chopper experience with both proton and negative ion beams and the ability of these systems to tailor the Linac beam to the diverse requirements of its users; normal accelerator injection, neutron therapy beam, and electron cooling experiments. This flexibility plus a cleaner beam pulse, improved thyratron operation, and mechanical modularity are the results of recent improvements. Additional benefits have been increased reliability and ease of service to the 750-KeV chopper. 3 refs.

International Nuclear Information System (INIS)

An electron accelerator unit is described for electron beam therapy, comprising: a source of an electron beam; means for finally directing at least a portion of the beam to a therapy site, the directing means being mechanically independent of, and electrically isolated from, the source, and having a target area; and means for aligning the source with the directing means, the aligning means comprising means for projecting at least one beam of light from the source toward the target area.

Energy Technology Data Exchange (ETDEWEB)

No abstract prepared.

Energy Technology Data Exchange (ETDEWEB)

The performance of the PSI/ETH focused ion beam (FIB) system has been improved to produce ion beams of very low energies down to 40 eV with a reasonable spot size of 1 {mu}m at 200 eV. (author) 2 figs., 1 ref.

UK PubMed Central (United Kingdom)

The issue of beam-induced damage on diffractive hard X-ray optics is addressed. For this purpose a systematic study on the radiation damage induced by a high-power X-ray beam is carried out in both...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

A method for conditioning electron beams is proposed, making use of the TM{sub 210} mode of microwave cavities, to reduce the axial velocity spread within the beam, in order to enhance gain in resonant electron beam devices, such as the free-electron laser (FEL). Effectively, a conditioner removes the restriction on beam emittance. The conditioner is analyzed using a simple model for beam transport and ideal RF cavities. Analysis of an FEL is employed to evaluate performance with reduced axial velocity spread. Examples of FELs are presented showing the distinct advantage of conditioning.

Energy Technology Data Exchange (ETDEWEB)

The production of polarized negative ion beams by ''collisional pumping'' is described. Collisional pumping utilizes repeated charge changing collisions in a thick electron-spin-polarized gas or vapor target to form a polarized fast atom beam. The polarized fast atom beam is then partially converted into a polarized negative ion beam in a vapor target. Analysis is presented for a hydrogen beam passing through either a thick polarized H atom target or a thick polarized alkali target. Large polarizations and large currents may be possible.

Energy Technology Data Exchange (ETDEWEB)

The requirements for transporting high-current, negative-ion beams are presented with particular emphasis on applications involving negative-hydrogen-ion beams. In addition to the usual matching and steering problems, particular attention must be paid to beam emittance growth in the transport system. Depending on the application, a number of approaches have been developed using both magnetic and electric lenses. I discuss the design considerations for transporting and matching these beams to radiofrequency quadrupole accelerators, and present a survey of the various types of beamlines now used for negative-ion beams.

Energy Technology Data Exchange (ETDEWEB)

The requirements for transporting high-current, negative-ion beams are presented with particular emphasis on applications involving negative-hydrogen-ion beams. In addition to the usual matching and steering problems, particular attention must be paid to beam emittance growth in the transport system. Depending on the application, a number of approaches have been developed using both magnetic and electric lenses. I discuss the design considerations for transporting and matching these beams to radiofrequency quadrupole accelerators, and present a survey of the various types of beamlines now used for negative-ion beams.

Energy Technology Data Exchange (ETDEWEB)

An electrostatic beam steering mechanism (ESM) has been designed and tested to deflect negative ion beams consisting of multi-beamlets. A steering angle of 10 mrad was obtained within the deviation of less than 1 mrad by biasing two electrodes at 0.5 kV and -0.75 kV for 120 keV H{sup -} ion beam. The current flowing to the positive electrode was no more than 10% of the beam current at a pressure of 2.8x10{sup -5} Torr. (author)

International Nuclear Information System (INIS)

The motivation for using a tandem electrostatic accelerator as an electron accelerator for a free electron laser (FEL) is presented. The adaptation of the HVEC EN tandem at the Weizmann Institute for this purpose, electron beam optics and nonlinear FEL computation relevant for this FEL realization are described. In the tandem configuration the terminal is held at a positive potential. The electron beam is accelerated from ground potential to the terminal in one beam tube and then decelerated down the other beam tube. The FEL wiggler and cavity are at the terminal. Due to the beam energy recovery this scheme produces a high power beam at the terminal with a small investment in electrical power. (orig.).

Energy Technology Data Exchange (ETDEWEB)

A beam position monitoring system has been implemented in the first third of the SLC linac which provides a complete scan of the trajectory on a single beam pulse. The data is collected from the local micro-computers and viewed with an updating display at a console or passed on to application programs. The system must operate with interlaced beams so the scans are also interlaced, providing each user with the ability to select the beam, the update rate, and the attenuation level in the digitizing hardware. In addition each user calibrates the hardware for his beam. A description of the system architecture will be presented. 6 refs., 4 figs.

International Nuclear Information System (INIS)

To achieve high efficiency for the conversion of electron kinetic energy in an electron beam to electromagnetic energy in a Free Electron Laser (FEL), it is important to improve the beam quality. And hence, it is necessary to study and minimize the emittance growth of the beam. According to the requirements for the beam quality in an FEL, the author analyzed the emittance growth caused by the jump of the electric field in an accelerator, energy increase, wakefield in a waveguide, space charge effect and distribution of particles in a beam as well as the wakefield in a deflect system etc. The author also estimated the emittance change caused by the variation of the microwave field from the gun to the first accelerator for such case.

International Nuclear Information System (INIS)

Electrostatic plasma simulation code for 2D rectangular geometry is presented. Main distinguishing feature of the code is its orientation on the beam-plasma interaction. The code and its graphical interface were developed using MATLAB programming language. Simulation results of inhomogeneous plasma interaction with modulated electron beams of different width are compared. In case of wide beam the front of Langmuir waves generated in point of local plasma resonance is planar and in case of thin beam (or ribbon beam) the front has approximately half-circular form.

CERN Multimedia

Theo de Visser and Farshid Feyzi in front of main beam of YE3 cart at HHM in Shanghai.

Energy Technology Data Exchange (ETDEWEB)

A study of the electron beam dynamics in the linac is conducted for the FERMI free electron laser (FEL) founded for construction at the Sincrotrone Trieste.

Science.gov (United States)

... electronic feedback system' connected to a Q switch ... The use of acousto-optic (AO) beam steering devices for BMDO (SDI) applications is very ...

Science.gov (United States)

Consideration is given to the stability of negative ion beams which are neutralized through ionization of a background gas. Two types of instabilities are examined. First, beam-plasma instabilities are analyzed with the dispersion relation showing that they are unimportant if the beam velocity is less than the electron thermal velocity. Second, results of a computer simulation on the flow of a cylindrical beam and the resulting background plasma show that when the background neutral gas density is less than or approximately equal to a critical density as instability occurs. This critical density is the density that would be needed to space-charge neutralize the beam if the positive ions were not retarded by the beam. An approximate dispersion relation indicates that the nature of the instability is a transverse positive-ion acoustic wave which couples to the ...

Energy Technology Data Exchange (ETDEWEB)

A case is reported of a 23-year old male with multiple glomus tumours that showed marked involution after he had electron beam therapy. (author).

International Nuclear Information System (INIS)

There is currently great interest in combining focused ion beam (FIB) and scanning electron microscopy technologies for advanced studies of polymeric materials and biological microstructures, as well as for sophisticated nanoscale fabrication and prototyping. Irradiation of electrically insulating materials with a positive ion beam in high vacuum can lead to the accumulation of charge, causing deflection of the ion beam. The resultant image drift has significant consequences upon the accuracy and quality of FIB milling, imaging and chemical vapour deposition. A method is described for suppressing ion beam drift using a defocused, low-energy primary electron beam, leading to the derivation of a mathematical expression to correlate the ion and electron beam energies and currents with other parameters required for electrically stabilizing these challenging ...

CERN Document Server

Feed-forward compensation for transient beam loading of the 805 MHz debuncher for the Fermilab linac upgrade

International Nuclear Information System (INIS)

A 20-MeV proton accelerator is developed by Proton Engineering Frontier Project (PEFP) at Korea Atomic Energy Research Institute (KAERI). The 20MeV accelerator consists of 50keV proton injector, 3MeV RFQ (Radio frequency Quadrupole), 20MeV DTL (Drift Tube Linac) and 20MeV beam line. The beam profile was measured at the end of the 20MeV beam line with wire scanner. Moreover the beam emittance was calculated from the quad scan method using beam line quadrupole magnets. In this paper, the beam profile measurement results are presented and the emittance measurement from the quad scan method is discussed

Energy Technology Data Exchange (ETDEWEB)

Accelerator concepts for heavy-ion fusion require small emittance, high-current beams. Such applications could include funnels in which high-current, like-charged particle beams are interlaced to double beam current while retaining small emittances. The first experimental demonstration confirming the beam dynamics of the funnel principle was recently completed at Los Alamos National Laboratory. A single-leg prototype 5-MeV, H{sup {minus}} funnel was successfully tested. This single-beam demonstration explored physics issues of a two-beam funnel. It contained elements for emittance control, position control, and rf deflection, as well as diagnostics for measurement of beam intensity, position and angle centroids, energy and phase centroids, and transverse and longitudinal phase-space distributions. Results of the experiment will be presented ...

Science.gov (United States)

In this paper, we investigate the effect of the solid surface on the fluid-fluid intermolecular potential energy. This modified fluid-fluid interaction energy due to the inducement of a solid surface is used in the grand canonical Monte Carlo (GCMC) simulation of various noble gases, nitrogen, and methane on graphitized thermal carbon black. This effect is such that the effective interaction potential energy between two particles close to surface is less than the potential energy if the solid substrate is not present. With this modification the GCMC simulation results agree extremely well with the experimental data over a wide range of pressures while the simulation results with the unmodified potential energy give rise to a shoulder near the neighborhood of monolayer coverage and the significant overprediction of the second and higher layer coverages. In particular the unmodified GCMC results exhibit very sharp change in those higher layers while the experimental data have a much ...

International Nuclear Information System (INIS)

During the operation of the Fast Flux Test Facility (FFTF), radioactive gases, primarily xenon and krypton, will be produced which will require processing and storing. Two systems have been installed in the FFTF for handling these gases: (1) one to handle, primarily, the reactor cover gas system, and (2) a second to handle the cells and cover gas systems, other than the reactor, whose atmosphere may become contaminated. The system that processes the reactor cover gas, which is argon, is called the Radioactive Argon Processing System (RAPS). The effluent argon from RAPS will normally be sufficiently decontaminated to allow its reuse as the reactor cover gas. If the radioactive level in the RAPS becomes too high, the exhaust stream will be diverted to the Cell Atmosphere Processing System (CAPS), a system which can function as a backup to RAPS. The design and operation of the RAPS and CAPS systems are described and certain safety aspects of the systems are discussed. ...

International Nuclear Information System (INIS)

... Union (INTAS), Brussels (Belgium) Science and Technology Center in Unkraine,

KoreaScience (Korea)

Full Text Available

International Nuclear Information System (INIS)

... radiation parity photonuclear reactions polarized beams resonance

Energy Technology Data Exchange (ETDEWEB)

No abstract prepared.

KoreaScience (Korea)

Full Text Available

CERN Document Server

First test with new ASACUSA trap show promise for future antihydrogen beam experiments.

International Nuclear Information System (INIS)

... Union (INTAS), Brussels (Belgium) Science and Technology Center in Unkraine,

KoreaScience (Korea)

Full Text Available

Energy Technology Data Exchange (ETDEWEB)

Accelerators can not be improved without the development of adequate beam instruments and diagnostic tools. This year this statement is particularly right: a lot of contributions are dedicated to beam monitoring and to the design of new beam monitors based on original technologies. This document gathers about 100 contributions.

International Nuclear Information System (INIS)

... Union (INTAS), Brussels (Belgium) Science and Technology Center in Unkraine,

Science.gov (United States)

We describe calculations of the energy loss, range, stopping power, multiple scattering, and other related properties of a high-energy heavy-ion beam at any one of a set of beam line elements. A beam line element (e.g., any beam modification, detection, or control device) is characterized by its thickness, areal density, aperture, and function. The loss of multiply scattered particles to any finite-aperture detector is calculated in the small-angle approximation, and the position of the Bragg peak, as given by particles stopping in the second of two ionization chambers used for Bragg curve measurements, is estimated. A general purpose computer program, PROPAGATE, has been written to allow addition, deletion, and modification of the beam line elements used in the calculation and to provide a convenient means of repeating such calculations for arbitrary beam ...

International Nuclear Information System (INIS)

The properties of negative-ion beams are very important for designing negative-ion apparatus and applications of negative-ion beams, especially, electron detachment cross-sections at the interaction between negative-ion beams and gas particles in the transport system, and secondary-electron emission factors when negative ions are incident on solid surfaces. These properties of negative-ion beams were investigated experimentally as a function of the ion energy under 50 keV. The single electron detachment cross-sections are almost constant in the other of 10"-"1"5 cm"2 in this energy range, but double electron detachment cross-sections increase in proportion to the ion velocity and much smaller than the single one. As for the secondary-electron emission factor, the emission factors for negative-ion beam are found to be larger by 1 than those for positive-ion ...

International Nuclear Information System (INIS)

A book has been written to introduce the physical aspects of the radiotherapy electron beam by presenting a summary of the developments in this field. The first chapter is a brief introduction to the technology of medical accelerators with emphasis on the electron beam production facilities. Chapter 2 describes the interaction processes at the atomic level once the electron beam enters the medium. Chapter 3 is concerned with the various properties of the electron beam purely from the clinical point of view. The electron beam algorithms and models for distribution calculations are covered in Chapter 4 with inclusion of age diffusion and multiple scattering approaches. The factors affecting the beam distribution in a patient, with inhomogeneities, surface irregularities, backscattering etc. are discussed in Chapter 5. The last two chapters are devoted to electron ...

Energy Technology Data Exchange (ETDEWEB)

The polarization of extracted SATURNE II proton beam as a function of different ion source configurations was studied. Two distinct experiments were necessary for this purpose. In the first one, the left-right instrumental asymmetry of the beam polarimeter was determined using an unpolarized beam. In the second one this correction factor was applied to asymmetries measured with the beam from the polarized ion source in all polarization states. The measurements were carried out at the proton beam kinetic energy 0.80 GeV, where the pp-elastic scattering analyzing power is near its maximum. The results confirmed that the two so-called ``unpolarized states`` of the source were polarized to several percent, whereas the absolute values of the beam polarizations in the so-called ``polarized states`` were equal and opposite. It was observed that the hexapole lens of the ...

Energy Technology Data Exchange (ETDEWEB)

The conceptual design for a cyclotron that could possibly deliver a 10 MW proton beam, presented at the previous ADTT conference, is discussed in comparison with the operational experience gained with 0.9 MW beam power in the upgraded cyclotron facility at PSI that has reached the design goal of 1.5 mA at 590 MeV in 1995. Some critical aspects of the design are e.g. RF power and beam loading, beam loss and activation, space charge effects and bunching. 12 refs., 2 figs., 1 tab.

Energy Technology Data Exchange (ETDEWEB)

Requirements are provided for NSLS beam line front ends and vacuum interlocks. Guidelines are provided for UHV beam line vacuum systems, including materials, vacuum hardware (pumps, valves, and flanges), acoustic delay lines and beam line fast valves, instrumentation, fabrication and testing, and the NSLS cleaning facility. Also discussed are the design review for experimenters' equipment that would be connected to the NSLS and acceptance tests for any beam line to be connected with the ring vacuum. Also appended are a description of the acoustic delay line as well as the NSLS vacuum standards and NSLS procedures. (LEW)

Science.gov (United States)

Plasma generated in low-density vapor by a negative ion beam has been studied experimentally and computationally. We show that space charge neutralization of the beam occurs at very low vapor density, and that correspondingly the electron density may be much less than the beam and plasma ion densities. When there is a large local gas density, as in a charge changing cell, the resulting high electron density is also localized to the same region. Therefore, very few electrons will reach a negative ion accelerator even if it is placed one or two beam diameters from such a cell.

International Nuclear Information System (INIS)

With the development of an array of highly-segmented germanium detectors, it now becomes possible to perform in-flight #gamma#-ray spectroscopy experiments on intermediate energy beams with unprecedented #gamma#-ray energy resolution. Presented in this report are examples of two techniques in which SeGA, the most highly-segmented operational germanium array for in-flight spectroscopy with fast beams, was used for the detection of #gamma# rays. SeGA used in conjunction with a high-resolution magnetic spectrograph (S800) to detect the reaction residues in coincidence represents a powerful combination for in-beam #gamma#-ray studies.

Energy Technology Data Exchange (ETDEWEB)

We apply and modify the computer codes CAIN(P.Chen, G.Horton-Smith, T.Ohgaki, A.W.Weidemann, K.Yokoya, contributed to Workshop on Gamma-Gamma Colliders, Berkeley, CA, March 28-31, 1994; SLAC-PUB-6583.) and GUINEAPIG(D.Schulte (DESY), unpublished.) to make detailed studies of the beam-beam interaction in the SLAC design for a future linear collider (NLC), as well as to the proposed SLC2000 project. Using realistic beam distributions, we present simulations related to the tuning and optimization of luminosity in SLC2000 and NLC.

Energy Technology Data Exchange (ETDEWEB)

Longitudinal space charge (LSC) force can be a main effect driving the microbunching instability in the linac for an x-ray free-electron laser (FEL). In this paper, the LSC-induced beam modulation is studied using an integral equation approach that takes into account the transverse (radial) variation of LSC field for both the coasting beam limit and bunched beam. Changes of beam energy and the transverse beam size can be also incorporated. We discuss the validity of this approach and compare it with other analyses as well as numerical simulations.

CERN Document Server

We propose a new method to measure the metallicity of Type Ia supernova progenitors using Mn and Cr lines in the X-ray spectra of young supernova remnants. We show that the Mn to Cr mass ratio in Type Ia supernova ejecta is tightly correlated with the initial metallicity of the progenitor, as determined by the neutron excess of the white dwarf material before thermonuclear runaway. We use this correlation, together with the flux of the Cr and Mn Kalpha X-ray lines in the Tycho supernova remnant recently detected by Suzaku (Tamagawa et al. 2008) to derive a metallicity of log(Z) = -1.32 (+0.67,-0.33) for the progenitor of this supernova, which corresponds to log(Z/Zsun)= 0.60 (+0.31,-0.60) according to the latest determination of the solar metallicity by Asplund et al. (2005). The uncertainty in the measurement is large, but metallicities much smaller than the solar value can be confidently discarded. We discuss the implications of this result for future research on ...

Energy Technology Data Exchange (ETDEWEB)

The behaviour of tetracycline as an extracting agent for Sr, I, Ba, Mo, Tc, Zr, Nb, Cs, Ru, Te and U was studied and the influence of the acidity of the aqueous phase upon extraction of the elements mentioned was examined. Experiments were made to determine whether the species extracted into the organic phase is the complex formed between tetracycline and the elements considered and to determine the time of shaking necessary so that the equilibrium between the phases is attained. As a practical application, the possibility of using the tetracycline-benzyl alcohol system for separating the fission products sup(137)Cs, sup(140)La, sup(141)Ce, sup(103)Ru, sup(95)Nb from each other and from uranium is presented. The same study was made for sup(131)I, sup(99m)Tc, sup(99)Mo, sup(132)Te, sup(239)Np and uranium and the steps necessary for the separation of these elements are proposed.

Energy Technology Data Exchange (ETDEWEB)

Measurements of dissolved and atmospheric nitrous oxide (N{sub 2}O) are presented for three coastal environments: (1) the central North Sea, (2) the German Bight, and (3) the Gironde estuary. The contribution of coastal regions to the oceanic emissions of atmospheric N{sub 2}O were also determined. N{sub 2}O was measured with a gas chromatograph equipped with an electron capture detector and analyzed. The surface waters of the central North Sea and the German bight were found to be near equilibrium with the overlying atmosphere, while the mean saturation in the Gironde estuary was 132%. Mean saturations in coastal regions without estuaries or upwelling phenomena were only slightly higher than in the open ocean. When estuaries and regions with upwelling are included, however, approximately 60% of the oceanic N{sub 2}O flux is attributable to coastal regions. A review of published data indicated that previous studies have seriously underestimated N{sub 2}O sea-to-air ...

Energy Technology Data Exchange (ETDEWEB)

There are two non-equivalent sites of yttrium in the lattice of Y{sub 2}SiO{sub 5}. Both of them may be occupied substitutionally by Er{sup 3+}, resulting in a laser active material. We measured absorption spectra of Y{sub 2}SiO{sub 5}:Er{sup 3+} at several low temperatures and we studied its emission spectrum at 4.2 K following selective excitation of individual Stark components of the {sup 4}I{sub 13}2/ to {sup 4}I{sub 15}2/ transition by the light of a tunable colour centre laser. The results of these two experiments allow classification of the absorption and emission lines into two independent systems, thus yielding two energy level schemes 1 and 2. Moreover, simple crystal field calculations strongly suggest from which Y{sub 2}SiO{sub 5} crystallographic site spectrum 1 arises, and from which one spectrum 2. (author)

International Nuclear Information System (INIS)

We have studied the efficiency of ozone production by pulsed positive corona discharge in coaxial wire-cylinder geometry at atmospheric pressure. A corona discharge was generated by short (#approx#150 ns) high voltage pulses applied between a silver coated copper wire anode and stainless steel cylinder cathode in synthetic air. A pyrex probe and Teflon tube was used for collecting discharge products and an ozone concentration was monitored outside of the discharge chamber by a non-dispersive UV absorption technique. The production of ozone was investigated as a function of energy density (10"-"4-3x10"-"1 Wh l"-"1) delivered to the discharge volume by combining the discharge frequency (0.1-10 Hz) and airflow rate (1-32 l min"-"1). From ozone concentration measurements we have evaluated the ozone production, yield and production energy cost. The ozone production yield and cost vary in the range of 15-55 g kWh"-"1 and 35-110 eV/molecule. (author)

International Nuclear Information System (INIS)

High-spin states of "1"8"7Ir have been populated in the "1"7"6Yb("1"5N,4n) reaction and measured with the YRAST Ball spectrometer. The #pi#h _9_/_2 rotational band has been extended beyond the first alignment crossing, which was found at rotational frequency (#Planck constant#/2#pi#)#omega# _c #approx =#0.39 MeV . Two different scenarios for describing this crossing are considered: the alignment of an h _9_/_2 proton or i _1_3_/_2 neutron pair and it is concluded that a proton band crossing is more likely. A systematic study of the rotational alignment crossings in the #pi#h _9_/_2 bands in the N=104,106,108 isotopes of _7_3Ta,_7_5Re,_7_7Ir, and _7_9Au is presented.

Energy Technology Data Exchange (ETDEWEB)

Until 1990, in Tuscany, salt pollution of anti-salt insulators installed on high-tension transmission lines had led to rare breakdowns. On the contrary, in the last months of 1990, in most of Tuscany, following a strong libeccio wind coming from the Tyrrhenian Sea, and due to a long period of drought, salt deposits accumulated on the insulators of the high-voltage transmission lines (380 kV, 220 kV and 132 kV). This phenomenon not only took place in the coastal areas near Livorno, Pisa and Grosseto, but also in areas far away from the sea such as Florence, Prato, Arezzo and Siena. Following this, several high-tension lines, and whole sections of 380 kV electric stations went out of order, damaging the stations' equipment, insulators on the lines, and in particular porcelain insulators. The maintenance operations that were immediately undertaken consisted in washing operations, first focussed on stations, and then on lines. Several hundred men and some ...

International Nuclear Information System (INIS)

The atomic masses of the alkali-metal isotopes "6Li,"2"3Na,"3"9","4"1K,"8"5","8"7Rb, and "1"3"3Cs have been obtained from measurements of cyclotron frequency ratios of pairs of ions simultaneously trapped in a Penning trap. The results, with one standard deviation uncertainty, are: M("6Li)=6.015 122 887 4(16)u,M("2"3Na)=22.989769 282 8(26)u,M("3"9K)=38.963 706 485 6(52)u,M("4"1K)=40.961 825 257 4(48)u,M("8"5Rb)=84.911 789739(9)u,M("8"7Rb)=86.909 180 535(10)u, and M("1"3"3Cs)=132.905 451 963(13)u. Our mass of "6Li yields an improved neutron separation energy for "7Li of 7251.1014(45) keV.

International Nuclear Information System (INIS)

In this article is reviewed the role of Computed Tomography (CT) in thoracic complications following ortho topic liver transplantation (OLT). In a post-OLT population of 567 patients transplanted in the Italian institutions, 100 patients (17.6%) were examined with chest CT. It was reviewed data relative to the total number of examinations, clinical and/or radiographic indications, the CT technique-i.e., conventional (with (out) intravenous, i.v., contrast material) or high-resolution (HRCT). It also reviewed the radiologic patterns and their correlation with the other clinical, bronchoscopic and/or laboratory results. Of 152 chest CT examinations, 45 (29.6%) were performed because of clinical indications, 31 (20.4%) because of a radiographic abnormality, 64 (42.1%) because of clinical and radiographic abnormality, 64 (42.1%) because of clinical and radiographic indications, while in 12 cases (7.9%) the reasons were unknown; 133/152 (87.5%) examinations had been performed with ...

Energy Technology Data Exchange (ETDEWEB)

Using a 47 GeV electron beam, the Final Focus Test Beam (FFTB) produces vertical spot sizes around 70 nm. These small beam sizes introduce an excellent opportunity to develop and test high resolution Radio Frequency Beam Position Monitors (RF-BPMs). These BPMs are designed to measure pulse to pulse beam motion (jitter) at a theoretical resolution of approximately 1 nm. The beam induces a TM{sub 110} mode with an amplitude linearly proportional to its charge and displacement from the BPM's (cylindrical cavity) axis. The C-band (5,712 MHz) TM{sub 110} signal is processed and converted into beam position for use by the Stanford Linear Collider (SLC) control system. Presented are the experimental procedures, acquisition, and analysis of data demonstrating resolution of jitter near 25 nm. With the design of future e{sup +}e{sup -} linear ...

International Nuclear Information System (INIS)

The SPring-8 linac has been improved to realize stable top-up injection into the SPring-8 and the NewSUBARU storage rings. The beam energy instability of 0.02% rms in the long term was achieved by means of reducing RF variations, providing beam energy compensation, reinforcement of monitor systems and introduction of beam feedback controls: Variations in the RF power and phase have been reduced by improving the voltage regulation system for the klystron modulator, and by stabilizing the temperature drift of the atmosphere and cooling water in order to reduce the phase variation. A new synchronous oscillator synchronizes a beam trigger pulse and a 2856 MHz reference signal, reducing variation in the beam charge. A beam energy compression system (ECS) was installed to compensate for accidental energy variation and reduce the energy spread. ...

International Nuclear Information System (INIS)

The results of experiments with a short period (9.6 mm) wiggler sheet electron beam (1.0 mm x 2.0 cm) millimeter-wave free electron laser (FEL) amplifier are presented. This FEL amplifier utilized a strong wiggler field for sheet beam confinement in the narrow beam dimension and an offset-pole side-focusing technique for the wide dimension beam confinement. The beam analysis herein includes finite emittance and space-charge effects. High-current beam propagation was achieved as a result of extensive analytical studies and experimental optimization. A design optimization resulted in a low sensitivity to structure errors and beam velocity spread, as well as a low required beam energy. A maximum gain of 24 dB was achieved with a 1-kW injected signal power at 86 GHz, a 450-kV beam voltage, 17-A ...

Energy Technology Data Exchange (ETDEWEB)

Recently Emma and Stupakov identified a fatal flaw in a Free Electron Laser (FEL) beam conditioning scheme. They showed that the conditioning is always accompanied by a projected transverse emittance growth that is so large as to make the beam conditioning completely impractical for short wavelength FELs. Furthermore, they provided a general proof along with evidence of computer simulation and reached a conclusion that any beam conditioner, regardless of the method, would suffer from the same constraints and limitations. In this paper, the author proposes an easy surgical removal of the fatal flaw by making a critical yet simple modification to the very scheme analyzed, thus resurrect the beam conditioning for short wavelength FELs. More generally, the also explain why a general search for removing have failed, why the concept and definition of beam conditioning.

British Library Electronic Table of Contents (United Kingdom)

An assessment of the joint shear strength of exterior concrete beam-column joints reinforced internally with Glass Fibre Reinforced Polymer (GFRP) reinforcements under monotonically increasing load on beams keeping constant load on columns is carried out in this study. Totally eighteen numbers of specimens are cast and tested for different parametric conditions like beam longitudinal reinforcement ratio, concrete strength, column reinforcement ratio, joint aspect ratio and influence of the joint stirrups at the joint. Also finite element analysis is performed to simulate the behaviour of the beam-column joints under various parametric conditions. Based on this study, a modified design equation is proposed for assessing the joint shear strength of the GFRP reinforced beam-column specimens b...

Energy Technology Data Exchange (ETDEWEB)

The drift-kink instability in field-reversed configurations with a beam component is investigated by means of a three-dimensional particle simulation. The unstable mode with the toroidal mode number n=4 grows with the rate {gamma} {approx} 0.1 - 1.0{omega}{sub ci} for a strong beam current and deforms the plasma profile along the beam orbit in the vicinity of the field-null line. This mode is nonlinearly saturated as a result of the relaxation of current profile. Both the saturation level and the growth rate tend to increase as the ratio of the beam current to the plasma current I{sub b}/I{sub p} increases. It is also found that there is a threshold value of the beam velocity {upsilon}{sub b} {approx} {upsilon}{sub Ti} (ion thermal velocity) for the excitation of the instability. (author)

Energy Technology Data Exchange (ETDEWEB)

Typical beam lines are comprised of an assembly of vacuum valves and shutters referred to as a ''front end'', optical elements to monochromatize, focus and split the photon beam, and an experimental area where a target sample is placed into the photon beam and data from the interaction is detected and recorded. Windows are used to separate sections of beam lines that are not compatible with storage ring ultra high vacuum. Some experimental beam lines share a common vacuum with storage rings. Sections of beam lines are only allowed to vent up to atmospheric pressure using pure nitrogen gas after a vacuum barrier is established to protect ring vacuum. The front end may only be bled up when there is no current in the machine. This is especially true on the VUV storage ring where for most experiments, windows are not used. For the ...

International Nuclear Information System (INIS)

The first long pulse production of high power D"- ion beams has been demonstrated in the JT-60 U negative ion sources, each of which was designed to produce 22 A, 500 keV D"- ion beams. Voltage holding capability and the grid power loading were examined for long pulse production of high power D"- ion beams. From the correlation between voltage holding and the light intensity of cathodoluminescence from the Fiber Reinforced Plastic insulators, the acceleration voltage for stable voltage holding capability was found to be less than 320-340 kV where the light was sufficiently suppressed. By tuning the extraction voltage, the grid power loadings in the ion sources were decreased to the allowable levels for long pulse injection without a significant reduction of the beam power. After tuning the acceleration and extraction voltages, D"- ion beams of 12.5 and 9.8 A were produced at 340 keV ...

UK PubMed Central (United Kingdom)

A stiff skin forms on surface areas of a flat polydimethylsiloxane (PDMS) upon exposure to focused ion beam (FIB) leading to ordered surface wrinkles. By controlling the FIB fluence and area of exposure...Full Text Available

CERN Document Server

Residual Stresses in Ta, Mo, Al and Pd Thin Films Deposited by E-Beam Evaporation Process on Si and Si/SiO 2 Substrates

Energy Technology Data Exchange (ETDEWEB)

An array of multiwire proportional counters has been employed to image, in 'real-time', a collimated neutron beam produced at an electron linac facility. Test results are presented, along with a discussion of the advantages of this technique.

International Nuclear Information System (INIS)

Progress in the development of negative ion sources and their application in fusion research is reviewed. (U.K.).

International Nuclear Information System (INIS)

For very low collision energies electron capture from excited hydrogen by multicharged ions is characterized by enormous cross sections, the predicted maximum being comparable to the geometric size of the Rydberg atom. The ion-atom merged-beams technique is being used to study these collisions for the variety of charge states and the wide range of energies (0.1 to 1000 eV/amu) accessible to the apparatus. A neutral D beam containing a Rydberg atom population proportional to 1/n"3 is produced by collisional electron detachment of 8 keV D"- in N_2 gas. An applied electric field results in the range (n=24--11) depending on the strength of the field applied. This beam is then merged with O"3"+ or O"5"+ ion beams at low relative collision velocities where the resultant beam-beam signal of D"+ due to electron loss is dominated by electron capture. From the sharp decrease in the observed ...

Energy Technology Data Exchange (ETDEWEB)

The Holifield Radioactive Ion Beam Facility (HRIBF) now under construction at the Oak Ridge National Laboratory will use the 25-MV tandem accelerator for the acceleration of radioactive ion beams to energies appropriate for research in nuclear physics; negative ion beams are, therefore, required for injection into the tandem accelerator. Because charge exchange is an efficient means for converting initially positive ion beams to negative ion beams, both positive and negative ion sources are viable options for use at the facility; the choice of the type of ion source will depend on the overall efficiency for generating the radioactive species of interest. A high-temperature version of the CERN-ISOLDE positive ion source has been selected and a modified version of the source designed and fabricated for initial use at the HRIBF because of its low emittance, relatively high ionization ...

UK PubMed Central (United Kingdom)

In view of poor local control rates obtained with standard treatment, intraoperative radiation (IORT) using electrons was combined with external beam irradiation and surgical resection, with or without...Full Text Available

UK PubMed Central (United Kingdom)

The purpose of this work is to develop a novel feature-based registration strategy to automatically map the rectal contours from planning computed tomography (CT) (pCT) to cone beam CT (CBCT). The rectal...Full Text Available

Science.gov (United States)

The evolution of the Doublet III neutral beam armor is followed from the initial design of a radiation cooled metallic tile to the present actively cooled graphite design. Results of the thermal and stress analyses that dictated the present design are reviewed.

Energy Technology Data Exchange (ETDEWEB)

Relativistic electron beams are used for generating high power microwaves. These microwave sources require electron beam generators spanning significant ranges in voltage and impedance. The pulsed power technology used to generate these electron beams is presented. Electron beam generators that produce beams with pulse durations in the 10 ns to 100 ns regime consist of an energy storage section, pulse shaping section, and an electron beam diode. The energy storage section is either a Marx generator or capacitor bank-pulsed transformer. The pulse shaping is done with high-voltage transmission lines. The electron beam diode is usually a cold-cathode, space-charge-limited flow device. For longer pulses (approx.1 ..mu..s) the energy storage and pulse shaping can be combined. Lumped-element pulsed-forming networks (PFN) can be designed to produce ...

International Nuclear Information System (INIS)

The localized Pt deposition on Si by 30 keV Ga"+ focused ion beam (FIB), 10 keV electron beam (EB) or dual beams (FIB and EB) using precursor gas has been compared by analysis using a 300 keV Be"2"+ microprobe with a beam spot size of 80 nm. The distribution of deposited Pt, Ga from the ion beam itself, and C from the precursor gas was obtained at and nearby the deposited areas by micro-RBS spectra and RBS mapping. All of the beam processed areas showed a uniform Pt distribution at the deposited areas. The amount of Pt atoms increased with the increase in ion or electron dose due to the decomposition of precursor gas. The thickness of Pt layer by EB is considerably less than that by FIB due to the reduced deposition rate. Ga atoms from the center of processed areas partly redeposited at and nearby the FIB processed areas within #approx#3 #mu#m. The Ga ...

CERN Document Server

A four-block collimator installed on a control table for positioning the alignment reference marks. Designed for use with SPS secondary beams, the collimator operates under vacuum conditions. See Annual Report 1976 p. 121 and photo 7701014.

International Nuclear Information System (INIS)

An array of multiwire proportional counters has been employed to image, in 'real-time', a collimated neutron beam produced at an electron linac facility. Test results are presented, along with a discussion of the advantages of this technique. (orig.).

CERN Document Server

In light beams with circular or elliptic polarization, the transverse energy flow consists of the "spin" and "orbital" parts. Both of them can induce the orbital motion of microparticles suspended within the field of a light beam, and this should be taken into account in experiments on the spin-to-orbital angular momentum conversion. The character of the spin, orbital and total transverse energy flows in circular Laguerre-Gaussian beams is studied analytically; graphical representations of the flows in the beam cross section (flow maps) are calculated and analyzed. The spin circulatory flow can be directed oppositely to the orbital one and/or to the polarization handedness. As a result, the total transverse energy circulation of a beam with homogeneous circular polarization can be of different handedness in different regions of the beam cross section, which are ...

Science.gov (United States)

The phase space beam analyzer is a measurement instrument that is applied in laser technology to perform analyses of the spatial and angular distribution of rays. We are interested in this instrument as a means to characterize non-coherent light sources. In this context, a closer look at the tolerances of this optical instrument was considered useful. Having a so-called quadrupole lens as a key element, the phase space beam analyzer is a device that features anamorphic optical properties. To describe these anamorphic properties, recurrence was made to a description by extended ray-transfer matrices. This formalism allows for an analysis of the alignment tolerances of the phase space beam analyzer and facilitates a study of the sensitivities of the instrument. The analysis is complemented using numerical ray tracing.

Energy Technology Data Exchange (ETDEWEB)

We have studied the effects of temperature fluctuations on the Advanced Light Source (ALS). By modeling the storage ring support structure, we find that fluctuations of {plus minus}2 to 3deg C in the tunnel will cause photon beam motion of the order of the beam size. Temperature stabilization at this level will allow the residual motion of the photon beams to be reduced by a second level of active feedback, operating on signals from photon beam position monitors. Air temperature in the experimental area and the temperature of cooling water serving the beamlines should be constant to {plus minus}1deg C. This will provide a suitable environment for experiments. (orig.).

Energy Technology Data Exchange (ETDEWEB)

We report experimental evidence of a previously unseen species-dependent effect in the transverse emittances of momentum analysed /sup 28/Si/sup -/, /sup 58/Ni/sup -/ and /sup 197/Au/sup -/ ion beams generated by caesium ion sputtering. The high-resolution emittance measurement techniques employed in this work have enabled us to estimate the energy spreads of these ion beams; differences in the widths of the energy distributions are the origin of the observed differences in emittances of the ion beams investigated. (author).

Science.gov (United States)

... Abstract : Two traces in flexible cables used in the Milstar agile beam antenna system failed during acceptance testing. ...

Science.gov (United States)

... transition to couple the emitted spontaneous radiation with the ammonia molecules and thus provide more amplification [2]. ...

International Nuclear Information System (INIS)

... level widths mev range 01-10 neutrons nuclear reactions proton beams

International Nuclear Information System (INIS)

The main features and advantages of a new low energy nuclear spectroscopic method, the in-beam spectroscopy are described. Results of in-beam spectroscopic experiments performed at the Institute of Nuclear Research (ATOMKI, Debrecen, Hungary) are summarized. Gamma spectra of in-beam produced odd-odd nuclei were measured, gamma-energies were determined. Measurement of gamma-gamma coincidences led to the construction of energy level schemes of the investigated nuclei. Internal conversion electron spectroscopy was used to determine the multipolarities of transitions. A few spectra and level schemes are presented to illustrate the review. Theoretical interpretation of experimental results are briefly summarized. (D.Gy.).

International Nuclear Information System (INIS)

The lifetime of the circulating electron beam in the Naval Research Laboratory modified betatron has been increased by more than 2 orders of magnitude with the addition of strong focusing windings to the device. The injected beam consistently spirals from the injector to the minor axis and is trapped. The #approx#0.5-kA trapped electron ring has been accelerated above 10 MeV from the injection energy of 0.5 to 0.6 MeV. The beam acceleration has been confirmed not only by the x-ray attenuation technique but also with the detection of photoneutrons.

Energy Technology Data Exchange (ETDEWEB)

No abstract prepared.

Energy Technology Data Exchange (ETDEWEB)

Average emittance data for ion beams extracted from cesium-sputter negative ion sources equipped with spherical, ellipsoidal, and cylindrical geometry cesium-surface ionizers are presented. The attributes of the respective source geometries are described in terms of their cesium ion optical properties. The results of recent measurement of the emittances of momentum-analyzed beams extracted from the ellipsoidal geometry source are also presented. These measurements indicate the presence of a species-dependent effect. The effect is believed to be attributable to differences in the energy spreads of the respective negative ion beams introduced by the sputter generation process.

Energy Technology Data Exchange (ETDEWEB)

Neutral atom beams with energies above 200 keV may be required for various purposes in magnetic fusion devices following TFTR, JET and MFTF-B. These beams can be produced much more efficiently by electron detachment from negative ion beams than by electron capture by positive ions. We have investigated the efficiency with which such neutral atoms can be produced by electron detachment in partially ionized hydrogen plasma neutralizers.

Science.gov (United States)

... attachment tube which is sketched in Fig. 1. It is mounted inside a cylindrical evacuated tube. A beam of thermal electrons ...

International Nuclear Information System (INIS)

We investigate the chargino production process #gamma##gamma# #-># (W-tilde)"+(W-tilde)"- at high energy #gamma##gamma# colliders in the framework of the minimal supersymmetric standard model (MSSM). Here the high energy #gamma# beams are obtained by the backward Compton scattering of the laser flush by the electron in the basic linear TeV ee colliders. We consider the polarization of the laser photons as well as the electron beams. Appropriate beam polarization could be effective to enhance the cross section to for us extract the signal from the dominant background #gamma##gamma# #-># W"+W"-. (author).

International Nuclear Information System (INIS)

A high-power microwave Free Electron Laser (FEL) experiment has been performed to study the inherent electron beam bunching that occurs in the FEL interaction. An induction linac delivered a 1 kA, 2.2 MeV electron beam to a FEL amplifier. In the process of amplifying the input signal of frequency 35 GHz to power levels of the order of 10 MW, the electron beam was bunched by the ponderomotive force. In this paper we describe the FEL experiment and the optical technique that was used to observe the bunches. Their properties as functions of the basic FEL parameters are discussed. copyright 1996 American Institute of Physics.

International Nuclear Information System (INIS)

... data deuteron beams energy dependence errors gamma radiation lead 203

Energy Technology Data Exchange (ETDEWEB)

This book explores the development, present, and future applications of proton microprobes in the micrometer range. Among the topics discussed: the use of proton beams for analytical purposes; techniques of focusing or collimating ion beams; improving and measuring beam spots; the analytical capabilities of the nuclear microprobe in comparison to other micro techniques; and applications and results by several internationally known microprobe laboratories.

Energy Technology Data Exchange (ETDEWEB)

Neutral beam systems for the next generation of magnetic fusion devices will be based on negative ions. Developments are progressing steadily, and large negative ion-based systems are under preparation for JT60-U and LHD, and are being considered for ITER. An overview of the physics of the production, acceleration and neutralization of large negative ion beams is given. The present state of the art in R and D is also surveyed. (Author).

Energy Technology Data Exchange (ETDEWEB)

Radiation therapy has shown definite technical improvement due to application of proton beam irradiation. Clinical results of proton beam therapy also suggested enlargement of indication ranges in radial treatment and decrease of post radiation damages of the treatment of cancers in deep-seated organs. Inprovement of result in cancer therapy could be expected by this treatment technique in the future.

International Nuclear Information System (INIS)

An apparatus allowing the photoexcitation of barium atomic beam over its whole surface is described. This photoexcitation is achieved by another barium spectrum emitted up steam of the beam by a cathodic out-flow produced at the exit oven. The fluorescence spectrum is studied in detail as well as the influence of different parameters, such as oven temperature, current intensity of the outflow, and excitation depth. A calculation shows how to determine Einstein coefficient, oscillator strengths and atomic lifetimes from our experimental measurements.

British Library Electronic Table of Contents (United Kingdom)

E-beam and gamma products from the radiolysis of aqueous solutions of (+-)-metoprolol tartrate, saturated in nitrogen, are analyzed by HPLC with on-line mass and UV detectors. The structures of 10 radiolytic products common to e-beam and gamma irradiations are elucidated by comparing their fragmentation pattern to that of (+-)-metoprolol. Two of the radiolytic products are also metabolites. Different routes for the formation of the radiolytic products are proposed.

Energy Technology Data Exchange (ETDEWEB)

The proton beam has a unique advantage over the electron and photon beams in that it can give very high radiation dose to the tumor volume, while effectively sparing the neighboring healthy tissue and organs. For the clinical application of the proton beam, it is very important to confirm the location of the proton beam in the patient, preferentially during the treatment. It has been suggested that the range of the proton beam in the patient can be determined by measuring prompt gammas from the proton beam passage. Recently, a prototype prompt-gamma scanning system has been constructed and tested using experimental and therapeutic proton beams. The measurement results for the proton beams of 70 . 230 MeV showed that a clear correlation exists between the distribution of the prompt gammas and the proton ...

Energy Technology Data Exchange (ETDEWEB)

During this report period our research efforts have concentrated on studies of the dissociation reactions of model peptides and other biologically important molecules. In addition, a considerable amount of research effort has been directed toward improving the apparatus used for laser-ion beam photodissociation. The instrumental improvements include some changes on the original apparatus, but most of this effort involved designing a second generation laser-ion beam photodissociation instrument.

Energy Technology Data Exchange (ETDEWEB)

The crabbing of an incident photon beam from a laser, and the electron beam with which it interacts at the conversion point, is shown to have the same efficiency as in head-on Compton scattering, but with the advantages of a crossing geometry. The resulting {gamma}-ray beam is also crabbed, which allows for a crossing collision point, while maintaining the luminosity at the same value it would have in a head-on collision. ((orig.)).

Energy Technology Data Exchange (ETDEWEB)

Characterization and optimization of electron-beam parameters are important aspects of optimizing free-electron laser (FEL) performance. The visible spontaneous emission ({lambda}{approximately}650 nm) from the 5-meter long undulator of the Boeing FEL experiment can be characterized in sufficient detail with a streak/spectrometer to deduce time-resolved electron-beam spatial position and profile, micropulse duration, and energy. 7 refs., 13 figs., 2 tabs.

Energy Technology Data Exchange (ETDEWEB)

We present our plans for a Monte-Carlo code simulating all possible combinations of (electromagnetic) interactions between colliding electron, positron, and both high-energy and laser photon beams, based on the ABEL code for beam-beam interaction. The implementation and first results for the laser-e{sup -} interaction are described. ((orig.)).

Energy Technology Data Exchange (ETDEWEB)

Recent experiments have explored the use of a free-electron laser (FEL) as a buncher for a microwave two-beam accelerator, and the subsequent driving of a standing-wave rf output cavity. Here the authors present a deeper analysis of the longitudinal dynamics of the electron bunches as they are transported from the end of the FEL and through the output cavity. In particular, the authors examine the effect of the transport region and cavity aperture to filter the bunched portion of the beam.

Energy Technology Data Exchange (ETDEWEB)

We present here the concept of a simple one dimensional photon beam position monitor for use with high power synchrotron radiation beams. It has micron resolution, reasonable linearity in an inexpensive design. Most important, is its insensitivity to diffusely scattered low energy radiation from components upstream of the monitor.

Energy Technology Data Exchange (ETDEWEB)

The studies using phantoms confirmed that the reduction of electron beam energy and minimization of X-ray contamination could be achieved when electron beam was interposed by an acrylic plate placed 20 cm anterior to a patient. Four patients of mycosis fungoides were treated with 8 MeV electron beam of a linear accelerator at UOEH Hospital from October 1981 to December 1986. Two of them were treated with this technique by placing 2 cm thick acrylic plate anterior to the patients and satisfactory results were obtained. Cutaneous lesions subsided remarkably with the dosage of 2000 cGy given in 2 months. Leucopenia due to bone marrow suppression was mild and the patients tolerated the treatment well.

Energy Technology Data Exchange (ETDEWEB)

The Front End Enclosure (FEE) of the Linac Coherent Light Source (LCLS) is a shielding housing located between the electron dump area and the first experimental hutch. The upstream part of the FEE hosts the commissioning diagnostics for the FEL beam. In the downstream part of the FEE, two sets of grazing incidence mirror and several collimators are used to direct the beam to one of the experimental stations and reduce the bremsstrahlung background and the hard component of the spontaneous radiation spectrum. This paper addresses the beam loss assumptions and radiation sources entering the FEE used for the design of the FEE shielding using the Monte-Carlo code FLUKA. The beam containment system prevents abnormal levels of radiations inside the FEE and ensures that the beam remains in its intended path is also described.

Energy Technology Data Exchange (ETDEWEB)

The morphological evolution of ripples formed on the surface of Cd2Nb2O7 pyrochlore single crystals by focused ion beam (FIB) bombardment was investigated using in situ electron microscopy. At high ion fluences and off-normal bombardment angles, faceted surface ripples with a terrace-like structure were observed. The ripple propagation direction was oriented along the projected ion beam direction at incident angles ranging from 35 to 65 following high-dose ion bombardment. One side of the terrace was found to be perpendicular to the incident ion beam direction, while the other side was parallel to the ion beam. The terrace propagation velocity and direction were determined and interpreted on the basis of this asymmetric structure. A model based on the propagation of a shock wave that effectively self-selects a stable slope, was developed in order to explain the observed faceted ripple formation.

Science.gov (United States)

A computer-based beam dosimetry measurement system for boron neutron capture therapy provides accurate, sensitive, and rapid readout and recording of all beam dose components, epithermal and thermal neutron flux, and gamma-ray dose rate. This dosimetric system includes input from the characterization of the epithermal neutron beam developed at the Massachusetts Institute of Technology, actual BPA pharmacokinetic data from a specific human subject being irradiated, output of MacNCTPLAN, a treatment planning system developed by the authors group, and input from the five on-line beam detectors. The purpose of this system and associated readout systems is to ensure that the desired dose is delivered to the subject within acceptable dose tolerances, e.g., {+-}5% of the target dose, and that any perturbations in the neutron beam that may occur during irradiation can be rapidly evaluated ...

Energy Technology Data Exchange (ETDEWEB)

We report the use of ion beam induced charge imaging to characterise the charge signal uniformity of epitaxial gallium nitride radiation detectors. The detectors were fabricated from 2 {mu}m thick semi-insulating gallium nitride, grown by MOCVD on a sapphire substrate. A carrier concentration of 1.4x10{sup 15} cm{sup -3} was measured using capacitance-voltage measurements. Ion beam induced charge imaging was carried out with a 2 MeV alpha particle beam focussed to a 3 {mu}m diameter and raster scanned across the device. The resulting ion beam images show excellent charge signal uniformity in this material with no evidence of material defects or polycrystalline structure on the micrometer length scale. No evidence of charge signal trapping was observed in these devices.

Energy Technology Data Exchange (ETDEWEB)

A focused ion beam (FIB) system produces a final beam spot size down to 0.1 {mu}m or less and an ion beam output current on the order of microamps. The FIB system increases ion source brightness by properly configuring the first (plasma) and second (extraction) electrodes. The first electrode is configured to have a high aperture diameter to electrode thickness aspect ratio. Additional accelerator and focusing electrodes are used to produce the final beam. As few as five electrodes can be used, providing a very compact FIB system with a length down to only 20 mm. Multibeamlet arrangements with a single ion source can be produced to increase throughput. The FIB system can be used for nanolithography and doping applications for fabrication of semiconductor devices with minimum feature sizes of 0.1 m or less. 13 figs.

Energy Technology Data Exchange (ETDEWEB)

A sensitivity study that used the particle tracking code PARMELA was performed on the Advanced Free-Electron Laser (AFEL). The tolerances on the alignment of the beam-line elements and the magnetic-field strengths were examined. Two base-line configurations were determined at the beginning of the study. The electron beam was then matched into the wiggler. The optimized beam-line parameters were varied independently and their sensitivities were judged with the criterion that the free-electron laser (FEL) effective-detuning parameter should not fluctuate more than 10%. The results of this study set the specifications for the alignment, for the sensitivity of the steering magnets, and for the accuracy of the magnetic field in the quadrupoles and dipoles. 5 figs., 3 figs., 3 tabs.

International Nuclear Information System (INIS)

Electrical properties of 16 keV, focused-ion-beam (FIB) (beam diameter: 1 #mu#m, current density: 50 mA/cm"2) boron-implanted silicon layers have been investigated as a function of beam scan speed and ion dose, and compared with those obtained by conventional implantation (current density: 0.4 #mu#A/cm"2). High electrical activation of the FIB implanted layers is obtained by annealing below 800"0C as a result of the increase in amorphous zones created in the implanted layers. Amorphous zone overlapping is assumed to occur at FIB implantation doses of 3 - 4 x 10"1"5 ions/cm"2 from the results of electrical activation and the carrier profile of implanted regions annealed at low temperature, if beam scan speed is lowered to about 10"-"2 cm/s. (author).

International Nuclear Information System (INIS)

We explore a novel phenomenon of focused ion beam (FIB) induced bending of carbon nanopillars or cantilever structures. The bending occurs towards the ion beam during scanning. The explanation of this bending has been sought on the basis of a model which considers temperature rise and gradients caused by the impinging ion beam. The process is controllable and reversible, which makes it highly suitable for in situ manipulation to make desired 3D shapes by the piecewise bending of the nanopillars and cantilever structures during their fabrication using electron beam or FIB chemical vapor deposition (EB-CVD or FIB-CVD). Its usefulness in the fabrication of nanosize mechanical components has been demonstrated by making a branch structure from a single cantilever.

Energy Technology Data Exchange (ETDEWEB)

Investigations have been conducted to determine the feasibility of using collisional cooling for reducing the energy spreads and, consequently, the emittances of negative-ion beams. We have designed a gas-filled RF-quadrupole ion cooler equipped with provisions for retarding energetic negative ion beams to energies below thresholds for electron detachment at injection and for re-acceleration to high energies after the cooling process. The device has been used to cool O{sup -} and F{sup -} ion beams with initial energy spreads, {Delta}E > 10 eV to final energy spreads, {Delta}E {approx} 2 eV FWHM. Overall transmission efficiencies of {approx}14% for F{sup -} beams have been obtained. Experimental results show that electron detachment is the major loss mechanism for negative ions.

International Nuclear Information System (INIS)

Coherent Smith-Purcell radiation, emitted from short-bunched electrons passing by a lamellar-type grating of aluminum, has been observed in the millimeter wave region. The energy of the electrons is either 42 MeV when they are accelerated by an L-band linear accelerator or 150 MeV accelerated by an S-band one. The intensity of the radiation is proportional to the square of the beam current. The radiation is linearly polarized, and the electric vector of the radiation is in the plane defined by the observing point and the beam trajectory. The intensity decreases with the beam height, i.e. the distance of the beam from the surface of the grating, in accordance with the modified Bessel function of zeroth order. copyright 1996 American Institute of Physics.

Energy Technology Data Exchange (ETDEWEB)

The emittances of hydrogen and deuterium negative ion beams produced by volume ion sources have been measured in a transverse plane normal to the beam trajectory. The extraction voltage was varied from 10 to 40 kV, and the transverse magnetic field in the Penning discharges was varied from 0.1 to 0.2 T. Measurements were made on beams with current densities up to 60 mA/cm/sup 2/ at Oak Ridge National Laboratory with an emittance scanner originally developed at Los Alamos National Laboratory. The beam profile at the scanner can be used to improve the accuracy of the emittance measurements. Other factors affecting emittance measurements are discussed. This analysis may be applicable to other ion sources. 6 figs.

International Nuclear Information System (INIS)

Little clinical evidence has been provided to show the minimization of radiation resistance of tumors using high linear energy transfer radiation. We therefore investigated the radiobiological and molecular pathological aspects of carbon beam therapy. A total of 27 patients with squamous cell carcinoma (SCC) of the cervix were treated using a carbon beam and 50 control patients with SCC of the cervix using a photon beam. The expression of Ki-67, p53, and p27 proteins before radiotherapy and 5 and 15 days after therapy initiation were investigated using immunohistochemistry. Similar changes were observed in Ki-67 labeling index (LI) and p53 LI during carbon and photon beam therapies. However, for carbon beam therapy, the mean p27 LI significantly decreased from 25.2% before treatment to 18.6% on the 5th day after treatment initiation, followed by a significant increase to 36.1% on ...

International Nuclear Information System (INIS)

In a vacuum insulator, the narrow electron beam emitted from the cathode impinges on the anode and raises its temperature and also may produce high thermal stress. This high thermal stress, in conjuction with the surface electrostatic pressure may rupture the surface and detach particles from it. In this thesis, the interaction of high energy electron and laser beams with metals and semiconductors is investigated. The differential equations governing the physical processes involved in the interaction are solved by the finite element method. Effects of beam penetration into the material, variable beam reflectance at the surface, finite beam size and dependence of material properties on temperature are accounted for. The two-phase moving boundary problem, also known as the Stefan problem, is solved by an enthalpy formulation of the heat equation. Material deformation by thermal ...

International Nuclear Information System (INIS)

The NRL Long Pulse Induction Linac is being employed in a Free Electron Laser (FEL) experiment. The authors present results of beam transport and focusing experiments as well as measurements of the output radiation generated by various magnetic wigglers. The electron gun of the accelerator presently has a 17-cmdiam. cold cathode which is located in a nearly zero magnetic field (B /SUB z/ less than or equal to 5 G). The gun voltage is flat to within approx. = + or - 5% for 1.5 #mu#sec with this graphite brush cathode. The beam is focused by a series of solenoidal coils as it propagates through the 4-m-long accelerator."2 A solenoidal field which can be varied from 1-10 kG confines the beam in the FEL interaction region. Previous experiments were limited by poor beam transport, focusing, and matching into the relatively large solenoidal field in the FEL region. By smoothing the axial magnetic field ...

Energy Technology Data Exchange (ETDEWEB)

The synergistic effects of displacement damage and atomic hydrogen and helium on swelling of the ferritic/martensitic steel, F82H, has been investigated. The irradiation was performed at temperatures between 470 and 600 deg. C to 50 dpa (displacement per atoms) under conditions of simultaneous ion beams consisting of Fe{sup 3+}, He{sup +} and H{sup +} ions or Fe{sup 3+} and He{sup +} ions. The swelling of F82H steel under triple beams with 18 appm He/dpa and 70 appm H/dpa was larger than that under dual beams with 18 appm He/dpa. The swelling in F82H under triple beams increased with decreasing irradiation temperature from 0.1% to 3.2%, while swelling under dual beams was between 0.04% and 0.08%. On the other hand, in the case of triple beam irradiation with a high ratio of gas/dpa, the swelling tended to increase with irradiation temperature. The swelling in ...

Energy Technology Data Exchange (ETDEWEB)

Radiotherapy with high-energy carbon ion beams can be more advantageous compared to photons because of better physical dose distribution and higher biological efficiency in tumour cell sterilization. Despite enhanced normal tissue sparing, damage incurred by normal cells at the beam entrance is unavoidable and may affect the progeny of surviving cells in the form of inheritable cytogenetic alterations. Furthermore, the quality of the beam along the Bragg curve is modified by nuclear fragmentation of projectile and target nuclei in the body. We present an experimental approach based on the use of a polymethylmethacrylate (PMMA) phantom that allows the simultaneous exposure to a particle beam of several biological samples positioned at various depths along the beam path. The device was used to measure the biological effectiveness of a 60 MeV/amu carbon-ion beam at ...

International Nuclear Information System (INIS)

The reactor core of TAPP-3 and 4 is divided into 14 power zones for spatial power control. Corresponding to each zone is a light water zonal compartment. The 14 ZCCs are located in two radial planes, each containing 7 ZCCs. For each zone, power measurement is carried out using three cobalt Self Powered Neutron Detectors (SPNDs) at appropriate locations close to the respective ZCC. Since the zone power as obtained by the true average of the healthy zone control detector (ZCD) readings belonging to a particular zone may not correspond to its actual power because these 3 detectors per zone, measure only point fluxes but the zone extends over a large core region. Therefore accurate estimation of zone power calibration factors is required to estimate the zone powers and also to provide effective spatial power control to avoid the xenon induced spatial power oscillations in large PHWRs like 540 MWe Reactor. This accurate calculation of zone power is carried out by FMS ...

Energy Technology Data Exchange (ETDEWEB)

Our institute has been investigating laser-produced tin, lithium and xenon plasma for extreme ultraviolet (EUV) light source of EUV lithography system, and found the highest conversion efficiency of 3% at 13.5 nm in 2% bandwidth. In the present paper, we introduce fabrication methods of density-controlled tin targets to generate relatively monochromatic EUV, and higher conversion efficiency than bulk tin. The first method is the nano-template method, where liquid tin solution was immersed into a polymer film with monodispersed size nano-particle. The density can be controlled by tin concentration of the solution. The target can be classified into mass-limited target. We have shown a tendency of monochromatic EUV emission around 13.5 nm with decreasing of tin density. The intensity was higher than tin foil with bulk density. The tendency has a merit to mitigate heat effect of the first EUV mirror. The fabrication method has another merit to control not only density ...

Energy Technology Data Exchange (ETDEWEB)

The adsorption equilibria of Kr, Xe and N{sub 2}, which are constituents of the off-gas from nuclear reprocessing processes, on representative adsorbents (Molecular Sieve 5A (MS5A) and activated charcoal) were studied. Adsorption experiments were conducted in the temperature range of 77 to 323 K using a packed bed column. The adsorption isotherms for the activated charcoal adsorbent were successfully correlated by the vacancy solution model. The adsorption isotherms for the MS5A adsorbent were properly correlated by the Langmuir model and the vacancy solution model. The adsorption experiments for the binary component systems (Kr-Xe, Kr-N{sub 2} systems) were also performed, and the results suggest that the coexistence of Xe greatly inhibits the adsorption of Kr. The coexistence of large amounts of N{sub 2} was also found to inhibit the adsorption of Kr. The experimental results for the adsorption equilibrium of binary component systems on the activated charcoal adsorbent were well ...

International Nuclear Information System (INIS)

The performance of a convolution/superposition based treatment planning system depends on the ability of the dose calculation algorithm to accurately account for physical interactions taking place in the tissue, key components of the linac head and on the accuracy of the photon beam model. Generally the user has little or no control over the performance of the dose calculation algorithm but is responsible for the accuracy of the beam model within the constraints imposed by the system. This study explores the dosimetric impact of limitations in photon beam modeling accuracy on complex 3D clinical treatment plans. A total of 70 photon beam models was created in the Pinnacle(TM) treatment planning system. Two of the models served as references for 6 MV and 15 MV beams, while the rest were created by perturbing the reference models in order to produce specific deviations in specific ...

Energy Technology Data Exchange (ETDEWEB)

Propagation of an intense charged particle beam pulse through a background plasma is a common problem in astrophysics and plasma applications. The plasma can effectively neutralize the charge and current of the beam pulse, and thus provides a convenient medium for beam transport. The application of a small solenoidal magnetic field can drastically change the self-magnetic and self- electric fields of the beam pulse, thus allowing effective control of the beam transport through the background plasma. An analytic model is developed to describe the self-magnetic field of a finite- length ion beam pulse propagating in a cold background plasma in a solenoidal magnetic field. The analytic studies show that the solenoidal magnetic field starts to infuence the self-electric and self-magnetic fields when ?ce > ?pe?b, where ?ce = e?/mec is the electron gyrofrequency, ...

Energy Technology Data Exchange (ETDEWEB)

An add-on multileaf collimator for electrons (eMLC) has been developed that provides computer-controlled beam collimation and isocentric dose delivery. The design parameters result from the design study by Gauer et al (2006 Phys. Med. Biol. 51 5987-6003) and were configured such that a compact and light-weight eMLC with motorized leaves can be industrially manufactured and stably mounted on a conventional linear accelerator. In the present study, the efficiency of an initial computer-controlled prototype was examined according to the design goals and the performance of energy- and intensity-modulated treatment techniques. This study concentrates on the attachment and gantry stability as well as the dosimetric characteristics of central-axis and off-axis dose, field size dependence, collimator scatter, field abutment, radiation leakage and the setting of the accelerator jaws. To provide isocentric irradiation, the eMLC can be placed either 16 or 28 cm above the ...

International Nuclear Information System (INIS)

The existing Tokamak Fusion Test Reactor Neutral Beam system is proposed to be modified for long pulse operation on the Tokamak Physics Experiment (TPX). Day one of TPX will call for one TFTR beamline modified for 1000 second pulse lengths oriented co-directional to the plasma current. The system design will be capable of accommodating an additional co-directional and a single counter directional beamline. For the TPX conceptual design, every attempt was made to use existing Neutral Beam hardware, plant facilities, auxiliary systems, service infrastructure, and control systems. This paper describes the moderate modifications required to the power systems, the ion sources, and the beam impinged surfaces of the ion dumps, the calorimeters, the various beam scrapers, and the neutralizers. Also described are the minimal modifications required to the vacuum, cryogenic, and gas systems and the major ...