APT Blanket System Loss-of-Coolant Accident (LOCA) Based on Initial Conceptual Design - Case 2: with Beam Shutdown Only

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hamm, L.L.

1998-10-07

This report is one of a series of reports that document normal operation and accident simulations for the Accelerator Production of Tritium (APT) blanket heat removal system. These simulations were performed for the Preliminary Safety Analysis Report. This report documents the results of simulations of a Loss-of-Flow Accident (LOFA) where power is lost to all of the pumps that circulate water in the blanket region, the accelerator beam is shut off and neither the residual heat removal nor cavity flood systems operate.

Computational design of high efficiency release targets for use at ISOL facilities

NASA Astrophysics Data System (ADS)

Liu, Y.; Alton, G. D.; Middleton, J. W.

1999-06-01

This report describes efforts made at the Oak Ridge National Laboratory to design high-efficiency-release targets that simultaneously incorporate the short diffusion lengths, high permeabilities, controllable temperatures, and heat removal properties required for the generation of useful radioactive ion beam (RIB) intensities for nuclear physics and astrophysics research using the isotope separation on-line (ISOL) technique. Short diffusion lengths are achieved either by using thin fibrous target materials or by coating thin layers of selected target material onto low-density carbon fibers such as reticulated vitreous carbon fiber (RVCF) or carbon-bonded-carbon-fiber (CBCF) to form highly permeable composite target matrices. Computational studies which simulate the generation and removal of primary beam deposited heat from target materials have been conducted to optimize the design of target/heat-sink systems for generating RIBs. The results derived from diffusion release-rate simulation studies for selected targets and thermal analyses of temperature distributions within a prototype target/heat-sink system subjected to primary ion beam irradiation will be presented in this report.

High-efficiency-release targets for use at ISOL facilities: computational design

NASA Astrophysics Data System (ADS)

Liu, Y.; Alton, G. D.

1999-12-01

This report describes efforts made at the Oak Ridge National Laboratory to design high-efficiency-release targets that simultaneously incorporate the short diffusion lengths, high permeabilities, controllable temperatures, and heat-removal properties required for the generation of useful radioactive ion beam (RIB) intensities for nuclear physics and astrophysics research using the isotope separation on-line (ISOL) technique. Short diffusion lengths are achieved either by using thin fibrous target materials or by coating thin layers of selected target material onto low-density carbon fibers such as reticulated-vitreous-carbon fiber (RVCF) or carbon-bonded-carbon fiber (CBCF) to form highly permeable composite target matrices. Computational studies that simulate the generation and removal of primary beam deposited heat from target materials have been conducted to optimize the design of target/heat-sink systems for generating RIBs. The results derived from diffusion release-rate simulation studies for selected targets and thermal analyses of temperature distributions within a prototype target/heat-sink system subjected to primary ion beam irradiation are presented in this report.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lampert, M.; BME NTI, Budapest; Anda, G.

A novel beam emission spectroscopy observation system was designed, built, and installed onto the Korea Superconducting Tokamak Advanced Research tokamak. The system is designed in a way to be capable of measuring beam emission either from a heating deuterium or from a diagnostic lithium beam. The two beams have somewhat complementary capabilities: edge density profile and turbulence measurement with the lithium beam and two dimensional turbulence measurement with the heating beam. Two detectors can be used in parallel: a CMOS camera provides overview of the scene and lithium beam light intensity distribution at maximum few hundred Hz frame rate, whilemore » a 4 × 16 pixel avalanche photo-diode (APD) camera gives 500 kHz bandwidth data from a 4 cm × 16 cm region. The optics use direct imaging through lenses and mirrors from the observation window to the detectors, thus avoid the use of costly and inflexible fiber guides. Remotely controlled mechanisms allow adjustment of the APD camera’s measurement location on a shot-to-shot basis, while temperature stabilized filter holders provide selection of either the Doppler shifted deuterium alpha or lithium resonance line. The capabilities of the system are illustrated by measurements of basic plasma turbulence properties.« less

Optical sensor for heat conduction measurement in biological tissue

NASA Astrophysics Data System (ADS)

Gutierrez-Arroyo, A.; Sanchez-Perez, C.; Aleman-Garcia, N.

2013-06-01

This paper presents the design of a heat flux sensor using an optical fiber system to measure heat conduction in biological tissues. This optoelectronic device is based on the photothermal beam deflection of a laser beam travelling in an acrylic slab this deflection is measured with a fiber optic angle sensor. We measure heat conduction in biological samples with high repeatability and sensitivity enough to detect differences in tissues from three chicken organs. This technique could provide important information of vital organ function as well as the detect modifications due to degenerative diseases or physical damage caused by medications or therapies.

Material characterisation and preliminary mechanical design for the HL-LHC shielded beam screens operating at cryogenic temperatures.

NASA Astrophysics Data System (ADS)

Garion, C.; Dufay-Chanat, L.; Koettig, T.; Machiocha, W.; Morrone, M.

2015-12-01

The High Luminosity LHC project (HL-LHC) aims at increasing the luminosity (rate of collisions) in the Large Hadron Collider (LHC) experiments by a factor of 10 beyond the original design value (from 300 to 3000 fb-1). It relies on new superconducting magnets, installed close to the interaction points, equipped with new beam screen. This component has to ensure the vacuum performance together with shielding the cold mass from physics debris and screening the cold bore cryogenic system from beam induced heating. The beam screen operates in the range 40-60 K whereas the magnet cold bore temperature is 1.9 K. A tungsten-based material is used to absorb the energy of particles. In this paper, measurements of the mechanical and physical properties of such tungsten material are shown at room and cryogenic temperature. In addition, the design and the thermal mechanical behaviour of the beam screen assembly are presented also. They include the heat transfer from the tungsten absorbers to the cooling pipes and the supporting system that has to minimise the heat inleak into the cold mass. The behaviour during a magnet quench is also presented.

Apparatus and method for characterizing thin film and interfaces using an optical heat generator and detector

DOEpatents

Maris, H.J.; Stoner, R.J.

1998-05-05

An optical heat generation and detection system generates a first non-destructive pulsed beam of electromagnetic radiation that is directed upon a sample containing at least one interface between similar or dissimilar materials. The first pulsed beam of electromagnetic radiation, a pump beam, produces a non-uniform temperature change within the sample. A second non-destructive pulsed beam of electromagnetic radiation, a probe beam, is also directed upon the sample. Physical and chemical properties of the materials, and of the interface, are measured by observing changes in a transient optical response of the sample to the probe beam, as revealed by a time dependence of changes in, by example, beam intensity, direction, or state of polarization. The system has increased sensitivity to interfacial properties including defects, contaminants, chemical reactions and delaminations, as compared to conventional non-destructive, non-contact techniques. One feature of this invention is a determination of a Kapitza resistance at the interface, and the correlation of the determined Kapitza resistance with a characteristic of the interface, such as roughness, delamination, the presence of contaminants, etc. 31 figs.

Apparatus and method for characterizing thin film and interfaces using an optical heat generator and detector

DOEpatents

Maris, Humphrey J; Stoner, Robert J

1998-01-01

An optical heat generation and detection system generates a first non-destructive pulsed beam of electromagnetic radiation that is directed upon a sample containing at least one interface between similar or dissimilar materials. The first pulsed beam of electromagnetic radiation, a pump beam (21a), produces a non-uniform temperature change within the sample. A second non-destructive pulsed beam of electromagnetic radiation, a probe beam (21b), is also directed upon the sample. Physical and chemical properties of the materials, and of the interface, are measured by observing changes in a transient optical response of the sample to the probe beam, as revealed by a time dependence of changes in, by example, beam intensity, direction, or state of polarization. The system has increased sensitivity to interfacial properties including defects, contaminants, chemical reactions and delaminations, as compared to conventional non-destructive, non-contact techniques. One feature of this invention is a determination of a Kapitza resistance at the interface, and the correlation of the determined Kapitza resistance with a characteristic of the interface, such as roughness, delamination, the presence of contaminants, etc.

Development progresses of radio frequency ion source for neutral beam injector in fusion devices.

PubMed

Chang, D H; Jeong, S H; Kim, T S; Park, M; Lee, K W; In, S R

2014-02-01

A large-area RF (radio frequency)-driven ion source is being developed in Germany for the heating and current drive of an ITER device. Negative hydrogen ion sources are the major components of neutral beam injection systems in future large-scale fusion experiments such as ITER and DEMO. RF ion sources for the production of positive hydrogen (deuterium) ions have been successfully developed for the neutral beam heating systems at IPP (Max-Planck-Institute for Plasma Physics) in Germany. The first long-pulse ion source has been developed successfully with a magnetic bucket plasma generator including a filament heating structure for the first NBI system of the KSTAR tokamak. There is a development plan for an RF ion source at KAERI to extract the positive ions, which can be applied for the KSTAR NBI system and to extract the negative ions for future fusion devices such as the Fusion Neutron Source and Korea-DEMO. The characteristics of RF-driven plasmas and the uniformity of the plasma parameters in the test-RF ion source were investigated initially using an electrostatic probe.

Conceptual design for an electron-beam heated hypersonic wind tunnel

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lipinski, R.J.; Kensek, R.P.

1997-07-01

There is a need for hypersonic wind-tunnel testing at about mach 10 and above using natural air and simulating temperatures and pressures which are prototypic of flight at 50 km altitude or below. With traditional wind-tunnel techniques, gas cooling during expansion results in exit temperatures which are too low. Miles, et al., have proposed overcoming this difficulty by heating the air with a laser beam as it expands in the wind-tunnel nozzle. This report discusses an alternative option of using a high-power electron beam to heat the air as it expands. In the e-beam heating concept, the electron beam ismore » injected into the wind-tunnel nozzle near the exit and then is guided upstream toward the nozzle throat by a strong axial magnetic field. The beam deposits most of its power in the dense air near the throat where the expansion rate is greatest. A conceptual design is presented for a large-scale system which achieves Mach 14 for 0.1 seconds with an exit diameter of 2.8 meters. It requires 450 MW of electron beam power (5 MeV at 90 A). The guiding field is 500 G for most of the transport length and increases to 100 kG near the throat to converge the beam to a 1.0-cm diameter. The beam generator is a DC accelerator using a Marx bank (of capacitors) and a diode stack with a hot cathode. 14 refs. 38 figs., 9 tabs.« less

Thermomagnetic recording and magnetic-optic playback system

NASA Technical Reports Server (NTRS)

Lewicki, G. W.; Guisinger, J. E. (Inventor)

1971-01-01

A magnetic recording and magneto-optic playback system is disclosed wherein thermomagnetic recording is employed. A transparent isotropic film is heated along a continuous path by a focused laser beam. As each successive area of the path is heated locally to the vicinity of its Curie point in the presence of an applied magnetic field, a magneto-optic density is established proportional to the magnetic field and fixed in place as the area cools once the laser beam moves on to an adjacent area. To play back the recorded data, the intensity of the laser beam is reduced to avoid reaching the vicinity of the Curie point of the film as it is scanned by the laser beam in the same manner as for recording. A Faraday effect analyzer and photo detector are employed as a transducer for producing an output signal.

A two-beam acoustic system for tissue analysis.

PubMed

Sachs, T D; Janney, C D

1977-03-01

In the 'thermo-acoustic sensing technique' (TAST), a burst of sound, called the 'thermometer' beam is passed through tissue and its transit time is measured. A focused sound field, called the heating field, then warms a small volume in the path of the therometer beam, in proportion to the absorption. Finally, the therometer beam burst is repeated and its transit time subtracted from that of the initial thermometer burst. This difference measures the velocity perturbation in the tissue produced by the heating field. The transit time difference is td = K integral of infinity-infinity IP dchi where K is the instrument constant, I the heating field intensity, and P a perturbation factor which characterizes the tissues. The integration is carried out along the path of the thermometer beam. The perturbation factor is P = (formula: see text) where C is the specific heat, rho the denisty, V the velocity of sound, (formula: see text) the temperature coefficient of velocity and alpha the heating field absorption coefficient which is apparently sensitive to tissue structure and condition. Experiments on a fixed human brain showed an ability to distinguish between various tissue types combined with a spatial resolution of better than 3 mm. Should predictions based on the data and theory prove correct, TAST may become a non-invasive alternative to biopsy.

Active shape control of composite blades using shape memory actuation

NASA Astrophysics Data System (ADS)

Chandra, Ramesh

2001-10-01

This paper presents active shape control of composite beams using shape memory actuation. Shape memory alloy (SMA) bender elements trained to memorize bending shape were used to induce bending and twisting deformations in composite beams. Bending-torsion coupled graphite-epoxy and kevlar-epoxy composite beams with Teflon inserts were manufactured using an autoclave-molding technique. Teflon inserts were replaced by trained SMA bender elements. Composite beams with SMA bender elements were activated by heating these using electrical resistive heating and the bending and twisting deformations of the beams were measured using a mirror and laser system. The structural response of the composite beams activated by SMA elements was predicted using the Vlasov theory, where these beams were modeled as open sections with many branches. The bending moment induced by a SMA bender element was calculated from its experimentally determined memorized shape. The bending, torsion, and bending-torsion coupling stiffness coefficients of these beams were obtained using analytical formulation of an open-section composite beam with many branches (Vlasov theory).

Benchmark testing of DIII-D neutral beam modeling with water flow calorimetry

DOE PAGES

Rauch, J. M.; Crowley, B. J.; Scoville, J. T.; ...

2016-06-02

Power loading on beamline components in the DIII-D neutral beam system is measured in this paper using water flow calorimetry. The results are used to benchmark beam transport models. Finally, anomalously high heat loads in the magnet region are investigated and a speculative hypothesis as to their origin is presented.

External-cavity beam combining of 4-channel quantum cascade lasers

NASA Astrophysics Data System (ADS)

Zhao, Yue; Zhang, Jin-Chuan; Zhou, Yu-Hong; Jia, Zhi-Wei; Zhuo, Ning; Zhai, Shen-Qiang; Wang, Li-Jun; Liu, Jun-Qi; Liu, Shu-Man; Liu, Feng-Qi; Wang, Zhan-Guo

2017-09-01

We demonstrate an external-cavity (EC) beam combining of 4-channel quantum cascade lasers (QCLs) with an output coupler which makes different QCL beams propagating coaxially. A beam combining efficiency of 35% (up to 75% near threshold) is obtained with a beam quality M2 of 5.5. A peak power of 0.64 W is achieved at a wavelength of 4.7 μm. The differences of spot characteristic between coupled and uncoupled are also showed in this letter. The QCLs in this EC system do not have heat crosstalk so that the system can be used for high power beam combining of QCLs.

Diode laser satellite systems for beamed power transmission

NASA Technical Reports Server (NTRS)

Williams, M. D.; Kwon, J. H.; Walker, G. H.; Humes, D. H.

1990-01-01

A power system composed of an orbiting laser satellite and a surface-based receiver/converter is described. Power is transmitted from the satellite to the receiver/converter by laser beam. The satellite components are: (1) solar collector; (2) blackbody; (3) photovoltaic cells; (4) heat radiators; (5) laser system; and (6) transmission optics. The receiver/converter components are: receiver dish; lenticular lens; photocells; and heat radiator. Although the system can be adapted to missions at many locations in the solar system, only two are examined here: powering a lunar habitat; and powering a lunar rover. Power system components are described and their masses, dimensions, operating powers, and temperatures, are estimated using known or feasible component capabilities. The critical technologies involved are discussed and other potential missions are mentioned.

Fiber optic temperature sensor gives rise to thermal analysis in complex product design

NASA Astrophysics Data System (ADS)

Cheng, Andrew Y. S.; Pau, Michael C. Y.

1996-09-01

A computer-adapted fiber-optic temperature sensing system has been developed which aims to study both the theoretical aspect of fiber temperature sensing and the experimental aspect of such system. The system consists of a laser source, a fiber sensing element, an electronic fringes counting device, and an on-line personal computer. The temperature measurement is achieved by the conventional double beam fringe counting method with optical path length changes in the sensing beam due to the fiber expansion. The system can automatically measure the temperature changes in a sensing fiber arm which provides an insight of the heat generation and dissipation of the measured system. Unlike the conventional measuring devices such as thermocouples or solid state temperature sensors, the fiber sensor can easily be wrapped and shaped to fit the surface of the measuring object or even inside a molded plastic parts such as a computer case, which gives much more flexibility and applicability to the analysis of heat generation and dissipation in the operation of these machine parts. The reference beam is being set up on a temperature controlled optical bench to facilitate high sensitivity and high temperature resolution. The measuring beam has a motorized beam selection device for multiple fiber beam measurement. The project has been demonstrated in the laboratory and the system sensitivity and resolution are found to be as high as 0.01 degree Celsius. It is expected the system will find its application in many design studies which require thermal budgeting.

Analysis of beam loss induced abort kicker instability

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang W.; Sandberg, J.; Ahrens, L.

2012-05-20

Through more than a decade of operation, we have noticed the phenomena of beam loss induced kicker instability in the RHIC beam abort systems. In this study, we analyze the short term beam loss before abort kicker pre-fire events and operation conditions before capacitor failures. Beam loss has caused capacitor failures and elevated radiation level concentrated at failed end of capacitor has been observed. We are interested in beam loss induced radiation and heat dissipation in large oil filled capacitors and beam triggered thyratron conduction. We hope the analysis result would lead to better protection of the abort systems andmore » improved stability of the RHIC operation.« less

Fiber-based modulated optical reflectance configuration allowing for offset pump and probe beams

NASA Astrophysics Data System (ADS)

Fleming, A.; Folsom, C.; Jensen, C.; Ban, H.

2016-12-01

A new fiber-based modulated optical reflectance configuration is developed in this work. The technique maintains the fiber-based heating laser (pump) and detection laser (probe) in close proximity at a fixed separation distance in a ceramic ferrule. The pump beam periodically heats the sample inducing thermal waves into the sample. The probe beam measures the temperature response at a known distance from the pump beam over a range of heating modulation frequencies. The thermal diffusivity of the sample may be calculated from the phase response between the input heat flux and the temperature response of a sample having a reflective surface. The unique measurement configuration is ideal for in situ measurements and has many advantages for laboratory-based systems. The design and development of the system are reported along with theoretical justification for the experimental design. The thermal diffusivities of Ge and SiC are measured and found to be within 10% of reported literature values. The diffusivity for SiO2 is measured with a relative difference of approximately 100% from the literature value when the ferrule is in contact with the sample. An additional measurement was made on the SiO2 sample with the ferrule not in contact resulting in a difference of less than 2% from the literature value. The difference in the SiO2 measurement when the ferrule is in contact with the sample is likely due to a parallel heat transfer path through the dual-fiber ferrule assembly.

Fiber-based modulated optical reflectance configuration allowing for offset pump and probe beams.

PubMed

Fleming, A; Folsom, C; Jensen, C; Ban, H

2016-12-01

A new fiber-based modulated optical reflectance configuration is developed in this work. The technique maintains the fiber-based heating laser (pump) and detection laser (probe) in close proximity at a fixed separation distance in a ceramic ferrule. The pump beam periodically heats the sample inducing thermal waves into the sample. The probe beam measures the temperature response at a known distance from the pump beam over a range of heating modulation frequencies. The thermal diffusivity of the sample may be calculated from the phase response between the input heat flux and the temperature response of a sample having a reflective surface. The unique measurement configuration is ideal for in situ measurements and has many advantages for laboratory-based systems. The design and development of the system are reported along with theoretical justification for the experimental design. The thermal diffusivities of Ge and SiC are measured and found to be within 10% of reported literature values. The diffusivity for SiO 2 is measured with a relative difference of approximately 100% from the literature value when the ferrule is in contact with the sample. An additional measurement was made on the SiO 2 sample with the ferrule not in contact resulting in a difference of less than 2% from the literature value. The difference in the SiO 2 measurement when the ferrule is in contact with the sample is likely due to a parallel heat transfer path through the dual-fiber ferrule assembly.

Design and evaluation of an electromagnetic beam waveguide for measuring electrical properties of materials

NASA Technical Reports Server (NTRS)

Bailey, M. C.

1994-01-01

A beam waveguide was designed that is based upon the propagation characteristics of the fundamental Gaussian beam and the focusing properties of spherical dielectric lenses. The 20-GHz, two-horn, four-lens system was constructed and experimentally evaluated by probing the field in a plane perpendicular to the beam axis at the center of the beam waveguide system. The critical parameters were determined by numerical sensitivity studies, and the lens-horn critical spacing was adjusted to better focus the beam at the probe plane. The measured performance was analyzed by consideration of higher order Gaussian-Laguerre beam modes. The beam waveguide system was successfully used in the measurements of the electromagnetic transmission properties of Shuttle thermal-protection tiles while the tile surface was being heated to reentry-level temperatures with a high-power laser.

Neutral beam dose and sputtering characteristics in an ion implantation system

NASA Technical Reports Server (NTRS)

Roberts, A. S., Jr.; Ash, R. L.; Berger, M. H.

1973-01-01

A technique and instrument design for calorimetric detection of the neutral atom content of a 60 keV argon ion beam. A beam sampling method is used to measure local heat flux to a small platinum wire at steady state; integration of power density profiles leads to a determination of equivalent neutral beam current. The fast neutral production occurs as a result of charge transfer processes in the region of the beam system between analyzing magnet and beam stop where the pressure remains less than .00001 torr. A description of the neutral beam detector is given in section along with a presentation of results. An elementary analysis of sputter material transport from target to substrate was performed; the analysis relates to semiconductor sputtering.

A wire calorimeter for the SPIDER beam: Experimental tests and feasibility study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pasqualotto, R., E-mail: roberto.pasqualotto@igi.cnr.it; Serianni, G.; Veltri, P.

2015-04-08

To study and optimize negative ion production and acceleration, in view of the use of neutral beam injectors in the ITER project, the SPIDER test facility (particle energy 100keV; beam current 50A, distributed over 1280 beamlets) is under construction in Padova, with the aim of testing beam characteristics and to verify the source proper operation, by means of several diagnostic systems. An array of tungsten wires, directly exposed to the beam and consequently heated to high temperature, is used in similar experiments at IPP-Garching to study the beam optics, which is one of the most important issues, in a qualitativemore » way. The present contribution gives a description of an experimental investigation of the behavior of tungsten wires under high heat loads in vacuum. Samples of tungsten wires are heated by electrical currents and the emitted light is measured by a camera in the 400-1100nm wavelength range, which is proposed as a calibration tool. Simultaneously, the voltage applied to the wire is measured to study the dependency of emissivity on temperature. The feasibility study of a wire calorimeter for SPIDER is finally proposed; to this purpose, the expected behaviour of tungsten with the two-dimensional beam profile in SPIDER is numerically addressed.« less

Long-pulse power-supply system for EAST neutral-beam injectors

NASA Astrophysics Data System (ADS)

Liu, Zhimin; Jiang, Caichao; Pan, Junjun; Liu, Sheng; Xu, Yongjian; Chen, Shiyong; Hu, Chundong; NBI Team

2017-05-01

The long-pulse power-supply system equipped for the 4 MW beam-power ion source is comprised of three units at ASIPP (Institute of Plasma Physics, Chinese Academy of Sciences): one for the neutral-beam test stand and two for the EAST neutral-beam injectors (NBI-1 and NBI-2, respectively). Each power supply system consists of two low voltage and high current DC power supplies for plasma generation of the ion source, and two high voltage and high current DC power supplies for the accelerator grid system. The operation range of the NB power supply is about 80 percent of the design value, which is the safe and stable operation range. At the neutral-beam test stand, a hydrogen ion beam with a beam pulse of 150 s, beam power of 1.5 MW and beam energy of 50 keV was achieved during the long-pulse testing experiments. The result shows that the power-supply system meets the requirements of the EAST-NBIs fully and lays a basis for achieving plasma heating.

Multi-foci beamforming for thermal strain imaging using a single ultrasound linear array transducer

PubMed Central

Nguyen, Man M; Ding, Xuan; Leers, Steven A.; Kim, Kang

2017-01-01

Ultrasound-induced thermal strain imaging (TSI) has been used to successfully identify lipid and water-based tissues in atherosclerotic plaques in some research settings. However, TSI faces several challenges to be realized in clinics. These challenges include motion artifacts, displacement tracking accuracy as well as limited heating capability which contributes to low thermal strain signal-to-noise ratio and a limited field of view. The goal of this paper is to address the challenge in heating tissue in TSI. Current TSI systems use separate heating and imaging transducers, which require physically aligning the heating and imaging beams and result in a bulky setup that limits in vivo operation. This paper proposes and evaluates a new design for heating beams that can be implemented on a linear array imaging transducer and can provide an improved heating area and efficiency as compared to previous implementations. The designed heating beams were implemented with a clinical linear array imaging transducer connected to a research ultrasound platform. In-vitro experiments using tissue mimicking phantoms with no blood flow showed that the new design resulted in an effective heating area of approximately 0.85 cm2 and a 0.3°C temperature rise in 2 seconds of heating, which compared well with in- silico finite element simulations. With the new heating beams, TSI was shown to be able to detect a lipid-mimicking rubber inclusion with a diameter of 1 cm from the water-based gelatin background, with a strain contrast of 2.3 (+0.14% strain in the rubber inclusion and −0.06% strain in the gelatin background). Lastly, lipid-based tissue in a 1-cm diameter human carotid endarterectomy (CEA) sample was identified with good agreement to histology. PMID:28318887

Method and apparatus for aerosol particle absorption spectroscopy

DOEpatents

Campillo, Anthony J.; Lin, Horn-Bond

1983-11-15

A method and apparatus for determining the absorption spectra, and other properties, of aerosol particles. A heating beam source provides a beam of electromagnetic energy which is scanned through the region of the spectrum which is of interest. Particles exposed to the heating beam which have absorption bands within the band width of the heating beam absorb energy from the beam. The particles are also illuminated by light of a wave length such that the light is scattered by the particles. The absorption spectra of the particles can thus be determined from an analysis of the scattered light since the absorption of energy by the particles will affect the way the light is scattered. Preferably the heating beam is modulated to simplify the analysis of the scattered light. In one embodiment the heating beam is intensity modulated so that the scattered light will also be intensity modulated when the particles absorb energy. In another embodiment the heating beam passes through an interferometer and the scattered light reflects the Fourier Transform of the absorption spectra.

Current-limited electron beam injection

NASA Technical Reports Server (NTRS)

Stenzel, R. L.

1977-01-01

The injection of an electron beam into a weakly collisional, magnetized background plasma was investigated experimentally. The injected beam was energetic and cold, the background plasma was initially isothermal. Beam and plasma dimensions were so large that the system was considered unbounded. The temporal and spatial evolution of the beam-plasma system was dominated by collective effects. High-frequency electrostatic instabilities rapidly thermalized the beam and heated the background electrons. The injected beam current was balanced by a return current consisting of background electrons drifting toward the beam source. The drift between electrons and ions gave rise to an ion acoustic instability which developed into strong three-dimensional turbulence. It was shown that the injected beam current was limited by the return current which is approximately given by the electron saturation current. Non-Maxwellian electron distribution functions were observed.

Heat-exchanger concepts for neutral-beam calorimeters

NASA Astrophysics Data System (ADS)

Thompson, C. C.; Polk, D. H.; McFarlin, D. J.; Stone, R.

1981-10-01

Advanced cooling concepts that permit the design of water cooled heat exchangers for use as calorimeters and beam dumps for advanced neutral beam injection systems were evaluated. Water cooling techniques ranging from pool boiling to high pressure, high velocity swirl flow were considered. Preliminary performance tests were carried out with copper, inconel and molybdenum tubes ranging in size from 0.19 to 0.50 in. diameter. Coolant flow configurations included: (1) smooth tube/straight flow; (2) smooth tube with swirl flow created by tangential injection of the coolant; and (3) axial flow in internally finned tubes. Additionally, the effect of tube L/D was evaluated. A CO2 laser was employed to irradiate a sector of the tube exterior wall; the laser power was incrementally increased until burnout occurred. Absorbed heat fluxes were calculated by dividing the measured coolant heat load by the area of the burn spot on the tube surface. Two six element thermopiles were used to accurately determine the coolant temperature rise. A maximum burnout heat flux near 14 kW/sq cm was obtained for the molybdenum tube swirl flow configuration.

The effect of beam-driven return current instability on solar hard X-ray bursts

NASA Technical Reports Server (NTRS)

Cromwell, D.; Mcquillan, P.; Brown, J. C.

1986-01-01

The problem of electrostatic wave generation by a return current driven by a small area electron beam during solar hard X-ray bursts is discussed. The marginal stability method is used to solve numerically the electron and ion heating equations for a prescribed beam current evolution. When ion-acoustic waves are considered, the method appears satisfactory and, following an initial phase of Coulomb resistivity in which T sub e/T sub i rise, predicts a rapid heating of substantial plasma volumes by anomalous ohmic dissipation. This hot plasma emits so much thermal bremsstrahlung that, contrary to previous expectations, the unstable beam-plasma system actually emits more hard X-rays than does the beam in the purely collisional thick target regime relevant to larger injection areas. Inclusion of ion-cyclotron waves results in ion-acoustic wave onset at lower T sub e/T sub i and a marginal stability treatment yields unphysical results.

Thermal deformation of cryogenically cooled silicon crystals under intense X-ray beams: measurement and finite-element predictions of the surface shape

PubMed Central

Zhang, Lin; Sánchez del Río, Manuel; Monaco, Giulio; Detlefs, Carsten; Roth, Thomas; Chumakov, Aleksandr I.; Glatzel, Pieter

2013-01-01

X-ray crystal monochromators exposed to white-beam X-rays in third-generation synchrotron light sources are subject to thermal deformations that must be minimized using an adequate cooling system. A new approach was used to measure the crystal shape profile and slope of several cryogenically cooled (liquid nitrogen) silicon monochromators as a function of beam power in situ and under heat load. The method utilizes multiple angular scans across the Bragg peak (rocking curve) at various vertical positions of a narrow-gap slit downstream from the monochromator. When increasing the beam power, the surface of the liquid-nitrogen-cooled silicon crystal deforms from a concave shape at low heat load to a convex shape at high heat load, passing through an approximately flat shape at intermediate heat load. Finite-element analysis is used to calculate the crystal thermal deformations. The simulated crystal profiles and slopes are in excellent agreement with experiments. The parameters used in simulations, such as material properties, absorbed power distribution on the crystal and cooling boundary conditions, are described in detail as they are fundamental for obtaining accurate results. PMID:23765298

Neutral Beam Development for the Lockheed Martin Compact Fusion Reactor

NASA Astrophysics Data System (ADS)

Ebersohn, Frans; Sullivan, Regina

2017-10-01

The Compact Fusion Reactor project at Lockheed Martin Skunk Works is developing a neutral beam injection system for plasma heating. The neutral beam plasma source consists of a high current lanthanum hexaboride (LaB6) hollow cathode which drives an azimuthal cusp discharge similar to gridded ion thrusters. The beam is extracted with a set of focusing grids and is then neutralized in a chamber pumped with Titanium gettering. The design, testing, and analyses of individual components are presented along with the most current full system results. The goal of this project is to advance in-house neutral beam expertise at Lockheed Martin to aid in operation, procurement, and development of neutral beam technology. ©2017 Lockheed Martin Corporation. All Rights Reserved.

SU-F-207-05: Excess Heat Corrections in a Prototype Calorimeter for Direct Realization of CT Absorbed Dose to Phantom

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen-Mayer, H; Tosh, R

2015-06-15

Purpose: To reconcile air kerma and calorimetry measurements in a prototype calorimeter for obtaining absorbed dose in diagnostic CT beams. While corrections for thermal artifacts are routine and generally small in calorimetry of radiotherapy beams, large differences in relative stopping powers of calorimeter materials at the lower energies typical of CT beams greatly magnify their effects. Work-to-date on the problem attempts to reconcile laboratory measurements with modeling output from Monte Carlo and finite-element analysis of heat transfer. Methods: Small thermistor beads were embedded in a polystyrene (PS) core element of 1 cm diameter, which was inserted into a cylindrical HDPEmore » phantom of 30 cm diameter and subjected to radiation in a diagnostic CT x-ray imaging system. Resistance changes in the thermistors due to radiation heating were monitored via lock-in amplifier. Multiple 3-second exposures were recorded at 8 different dose-rates from the CT system, and least-squares fits to experimental data were compared to an expected thermal response obtained by finite-element analysis incorporating source terms based on semi-empirical modeling and Monte Carlo simulation. Results: Experimental waveforms exhibited large thermal artifacts with fast time constants, associated with excess heat in wires and glass, and smaller steps attributable to radiation heating of the core material. Preliminary finite-element analysis follows the transient component of the signal qualitatively, but predicts a slower decay of temperature spikes. This was supplemented by non-linear least-squares fits incorporating semi-empirical formulae for heat transfer, which were used to obtain dose-to-PS in reasonable agreement with the output of Monte Carlo calculations that converts air kerma to absorbed dose. Conclusion: Discrepancies between the finite-element analysis and our experimental data testify to the very significant heat transfer correction required for absorbed dose calorimetry of diagnostic CT beams. The results obtained here are being used to refine both simulations and design of calorimeter core components.« less

The Supervisory Control System for the HL-2A Neutral Beam Injector

NASA Astrophysics Data System (ADS)

Li, Bo; Li, Li; Feng, Kun; Wang, Xueyun; Yang, Jiaxing; Huang, Zhihui; Kang, Zihua; Wang, Mingwei; Zhang, Guoqing; Lei, Guangjiu; Rao, Jun

2009-06-01

Supervisory control and protection system of the neutral beam injector (NBI) in the HL-2A tokamak is presented. The system is used for a safe coordination of all the main NBI subsystems. Because the system is based on computer networks with its transmission medium of optical fiber, its advantages in high operational stability, reliability, security and flexible functional expandability are clearly shown during the NBI commissioning and heating experiment in HL-2A.

Operational characteristics of a translation screen grid beam deflection system for a 5-cm Kaufman thruster

NASA Technical Reports Server (NTRS)

Lathem, W. C.; Hudson, W. R.

1972-01-01

Measurements of beam deflection angle with respect to spring positioning power and accelerator impingement current as a function of deflection angle were made on a 5-cm diameter system. Response time measurements on the translational grid beam deflection system showed that the time for the maximum deflection angle analyzed (+16.4 deg to -16.4 deg) could be reduced by a factor of nine by increasing the heating power applied to the positioning spring from 4 to 16 watts. At 14 watts the response time for maximum deflection was about 1 minute.

Suppression of energetic particle driven instabilities with HHFW heating

DOE PAGES

Fredrickson, E. D.; Taylor, G.; Bertelli, N.; ...

2015-01-01

In plasmas in the National Spherical Torus Experiment (NSTX) [Ono et al., Nucl. Fusion 40 (2000) 557] heated with neutral beams, the beam ions typically excite Energetic Particle Modes (EPMs or fishbones), and Toroidal, Global or Compressional Alfvén Eigenmodes (TAE, GAE, CAE). These modes can redistribute the energetic beam ions, altering the beam driven current profile and the plasma heating profile, or they may affect electron thermal transport or cause losses of the beam ions. In this paper we present experimental results where these instabilities, driven by the super-thermal beam ions, are suppressed with the application of High Harmonic Fastmore » Wave heating.« less

Resist heating effect on e-beam mask writing at 75 kV and 60 A/cm2

NASA Astrophysics Data System (ADS)

Benes, Zdenek; Deverich, Christina; Huang, Chester; Lawliss, Mark

2003-12-01

Resist heating has been known to be one of the main contributors to local CD variation in mask patterning using variable shape e-beam tools. Increasingly complex mask patterns require increased number of shapes which drives the need for higher electron beam current densities to maintain reasonable write times. As beam current density is increased, CD error resulting from resist heating may become a dominating contributor to local CD variations. In this experimental study, the IBM EL4+ mask writer with high voltage and high current density has been used to quantitatively investigate the effect of resist heating on the local CD uniformity. ZEP 7000 and several chemically amplified resists have been evaluated under various exposure conditions (single-pass, multi-pass, variable spot size) and pattern densities. Patterns were designed specifically to allow easy measurement of local CD variations with write strategies designed to maximize the effect of resist heating. Local CD variations as high as 15 nm in 18.75 × 18.75 μm sub-field size have been observed for ZEP 7000 in a single-pass writing with full 1000 nm spots at 50% pattern density. This number can be reduced by increasing the number of passes or by decreasing the maximum spot size. The local CD variation has been reduced to as low as 2 nm for ZEP 7000 for the same pattern under modified exposure conditions. The effectiveness of various writing strategies is discussed as well as their possible deficiencies. Minimal or no resist heating effects have been observed for the chemically amplified resists studied. The results suggest that the resist heating effect can be well controlled by careful selection of the resist/process system and/or writing strategy and that resist heating does not have to pose a problem for high throughput e-beam mask making that requires high voltage and high current densities.

Heating and scattering of ring-beam distributions by turbulence

NASA Technical Reports Server (NTRS)

Gray, P. C.; Pontius, D. H., Jr.; Matthaeus, W. H.

1995-01-01

Pickup ions in the solar wind are initially are born in ring-beam distributions, i.e. f(v) varies as delta(v(sub perpendicular) - V(sub sw)sin(Theta)) delta(v(sub parallel) - V(sub sw)cos(Theta)), where Theta is the angle between the solar wind velocity and the IMF(Interplanetary Magnetic Field), and V(sub sw) is the solar wind speed. Often the distribution has been presumed to relax to a distribution that is isotropic in Theta and essentially mono-energetic, a shell or a 'bi-spherical distribution.' However solar wind turbulence is capable of heating the ring distribution on the timescale of a few tens of gyroperiods, a timescale not greatly distinct from that required for pitch angle scattering to a shell. To describe this effect, we have performed test-particle studies of the heating/scattering of the ring beam distribution by MHD turbulence, adopting various models for the MHD fluctuations, including slab and fully dynamic 2D and 3D incompressible turbulence. Furthermore, a system composed of a cold ion ring and a background plasma is unstable to several kinetic plasma instabilities. We carried out kinetic simulations of the ring beam distribution, showing that plasma instabilities also rapidly energize and scatter particles. Results will be presented comparing relaxation and heating rates of the ring-beam distribution by the various mechanisms.

Development and Short-Range Testing of a 100 kW Side-Illuminated Millimeter-Wave Thermal Rocket

NASA Technical Reports Server (NTRS)

Bruccoleri, Alexander; Eilers, James A.; Lambot, Thomas; Parkin, Kevin

2015-01-01

The objective of the phase described here of the Millimeter-Wave Thermal Launch System (MTLS) Project was to launch a small thermal rocket into the air using millimeter waves. The preliminary results of the first MTLS flight vehicle launches are presented in this work. The design and construction of a small thermal rocket with a planar ceramic heat exchanger mounted along the axis of the rocket is described. The heat exchanger was illuminated from the side by a millimeter-wave beam and fed propellant from above via a small tank containing high pressure argon or nitrogen. Short-range tests where the rocket was launched, tracked, and heated with the beam are described. The rockets were approximately 1.5 meters in length and 65 millimeters in diameter, with a liftoff mass of 1.8 kilograms. The rocket airframes were coated in aluminum and had a parachute recovery system activated via a timer and Pyrodex. At the rocket heat exchanger, the beam distance was 40 meters with a peak power intensity of 77 watts per square centimeter. and a total power of 32 kilowatts in a 30 centimeter diameter circle. An altitude of approximately 10 meters was achieved. Recommendations for improvements are discussed.

Laser Stimulated Thermoluminescence

NASA Astrophysics Data System (ADS)

Abtahi, Abdollah

Techniques for localized heating of semi-infinite single-layer and two-layer structures are investigated theoretically and experimentally, motivated by applications in thermoluminescence (TL) dosimetry of ionizing radiation. The heat-conduction equations are solved by the Green's function technique to obtain the transient temperature distribution caused by exposure to laser beams of Gaussian and uniform circular intensity profiles. It is shown that the spatio-temporal temperature response is readily monitored by the TL response that results when layer configuration contains a thermoluminescent phosphor. The experiments for the verification of the developed theory are performed with two specially constructed TL detection systems, one featuring a laser beam of Gaussian profile and the other a uniform circular laser beam. Measurements of the thermoluminescent emission from a number of different TL systems are performed and compared with computed responses on the basis of simple electron kinetics. We experiment exclusively with the commercial TL phosphor LiF:Mg,Ti(TLD-100, Harshaw), the most widely used material in thermoluminescence dosimetry. We study in detail localized Gaussian beam heating of it in the form of 0.9 mm thick slabs, self-supporting firms of fine-grain powder in a polyimide (Kapton) matrix, and on substrates of LiF single crystals or borosilicate glass. Thermoluminescent layers on glass substrates have been heated with Gaussian and uniform circular intensity profiles in two different modes: the laser beam impinges onto (a) the phosphor layer, and (b) the glass substrate. It is demonstrated that the optical and thermal behavior of the dosimeters can be determined by these methods and that, furthermore, the thermoluminescence response of a given configuration can be simulated as a function of a number of experimental parameters such as laser power, beam size, substrate and TL-layer thicknesses, and configuration of the dosimeters. In addition, we have investigated the dependence of the luminous efficiency (normalized thermoluminescence yield) and peak heights on heating rates in the range from 4 K/s to 5500 K/s. The efficiency values obtained are then included in the comparison of experimental and theoretical TL responses curves for various laser powers.

An Experimental Evaluation of the Internal Flow Field of an Automotive Heating, Ventilating and Air Conditioning System

DTIC Science & Technology

1990-07-01

HVAC) was conducted. This study consisted of four primary experiments designed to provide a fairly complete description of the governing flow mechanisms...interest. In order to generate the 28 required optical characteristics, the laser beam was directed through a mechanical beam chopper and a series of...lenses. The beam chopper operated at a frequency of 75 chops per second to create series of laser pulses 1/75s in duration. Once chopped, the beam was

Varying stopping and self-focusing of intense proton beams as they heat solid density matter

NASA Astrophysics Data System (ADS)

Kim, J.; McGuffey, C.; Qiao, B.; Wei, M. S.; Grabowski, P. E.; Beg, F. N.

2016-04-01

Transport of intense proton beams in solid-density matter is numerically investigated using an implicit hybrid particle-in-cell code. Both collective effects and stopping for individual beam particles are included through the electromagnetic fields solver and stopping power calculations utilizing the varying local target conditions, allowing self-consistent transport studies. Two target heating mechanisms, the beam energy deposition and Ohmic heating driven by the return current, are compared. The dependences of proton beam transport in solid targets on the beam parameters are systematically analyzed, i.e., simulations with various beam intensities, pulse durations, kinetic energies, and energy distributions are compared. The proton beam deposition profile and ultimate target temperature show strong dependence on intensity and pulse duration. A strong magnetic field is generated from a proton beam with high density and tight beam radius, resulting in focusing of the beam and localized heating of the target up to hundreds of eV.

Varying stopping and self-focusing of intense proton beams as they heat solid density matter

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, J.; McGuffey, C., E-mail: cmcguffey@ucsd.edu; Qiao, B.

2016-04-15

Transport of intense proton beams in solid-density matter is numerically investigated using an implicit hybrid particle-in-cell code. Both collective effects and stopping for individual beam particles are included through the electromagnetic fields solver and stopping power calculations utilizing the varying local target conditions, allowing self-consistent transport studies. Two target heating mechanisms, the beam energy deposition and Ohmic heating driven by the return current, are compared. The dependences of proton beam transport in solid targets on the beam parameters are systematically analyzed, i.e., simulations with various beam intensities, pulse durations, kinetic energies, and energy distributions are compared. The proton beam depositionmore » profile and ultimate target temperature show strong dependence on intensity and pulse duration. A strong magnetic field is generated from a proton beam with high density and tight beam radius, resulting in focusing of the beam and localized heating of the target up to hundreds of eV.« less

FTIR spectrometer with solid-state drive system

DOEpatents

Rajic, Slobodan; Seals, Roland D.; Egert, Charles M.

1999-01-01

An FTIR spectrometer (10) and method using a solid-state drive system with thermally responsive members (27) that are subject to expansion upon heating and to contraction upon cooling. Such members (27) are assembled in the device (10) so as to move an angled, reflective surface (22) a small distance. The sample light beam (13) is received at a detector (24) along with a reference light beam (13) and there it is combined into a resulting signal. This allows the "interference" between the two beams to occur for spectral analysis by a processor (29).

Automated pinhole-aperture diagnostic for the current profiling of TWT electron beams

NASA Astrophysics Data System (ADS)

Wei, Yu-Xiang; Huang, Ming-Guang; Liu, Shu-Qing; Liu, Jin-Yue; Hao, Bao-Liang; Du, Chao-Hai; Liu, Pu-Kun

2013-02-01

The measurement system reported here is intended for use in determining the current density distribution of electron beams from Pierce guns for use in TWTs. The system was designed to automatically scan the cross section of the electron beam and collect the high-resolution data with a Faraday cup probe mounted on a multistage manipulator using the LabVIEW program. A 0.06 mm thick molybdenum plate with a pinhole and a Faraday cup mounted as a probe assembly was employed to sample the electron beam current with 0.5 µm space resolution. The thermal analysis of the probe with pulse beam heating was discussed. A 0.45 µP electron gun with the expected minimum beam radius 0.42 mm was measured and the three-dimensional current density distribution, beam envelope and phase space were presented.

Extension of electron cyclotron heating at ASDEX Upgrade with respect to high density operation

NASA Astrophysics Data System (ADS)

Schubert, Martin; Stober, Jörg; Herrmann, Albrecht; Kasparek, Walter; Leuterer, Fritz; Monaco, Francesco; Petzold, Bernhard; Plaum, Burkhard; Vorbrugg, Stefan; Wagner, Dietmar; Zohm, Hartmut

2017-10-01

The ASDEX Upgrade electron cyclotron resonance heating operates at 105 GHz and 140 GHz with flexible launching geometry and polarization. In 2016 four Gyrotrons with 10 sec pulse length and output power close to 1 MW per unit were available. The system is presently being extended to eight similar units in total. High heating power and high plasma density operation will be a part of the future ASDEX Upgrade experiment program. For the electron cyclotron resonance heating, an O-2 mode scheme is proposed, which is compatible with the expected high plasma densities. It may, however, suffer from incomplete single-pass absorption. The situation can be improved significantly by installing holographic mirrors on the inner column, which allow for a second pass of the unabsorbed fraction of the millimetre wave beam. Since the beam path in the plasma is subject to refraction, the beam position on the holographic mirror has to be controlled. Thermocouples built into the mirror surface are used for this purpose. As a protective measure, the tiles of the heat shield on the inner column were modified in order to increase the shielding against unabsorbed millimetre wave power.

Wide-angle ITER-prototype tangential infrared and visible viewing system for DIII-D.

PubMed

Lasnier, C J; Allen, S L; Ellis, R E; Fenstermacher, M E; McLean, A G; Meyer, W H; Morris, K; Seppala, L G; Crabtree, K; Van Zeeland, M A

2014-11-01

An imaging system with a wide-angle tangential view of the full poloidal cross-section of the tokamak in simultaneous infrared and visible light has been installed on DIII-D. The optical train includes three polished stainless steel mirrors in vacuum, which view the tokamak through an aperture in the first mirror, similar to the design concept proposed for ITER. A dichroic beam splitter outside the vacuum separates visible and infrared (IR) light. Spatial calibration is accomplished by warping a CAD-rendered image to align with landmarks in a data image. The IR camera provides scrape-off layer heat flux profile deposition features in diverted and inner-wall-limited plasmas, such as heat flux reduction in pumped radiative divertor shots. Demonstration of the system to date includes observation of fast-ion losses to the outer wall during neutral beam injection, and shows reduced peak wall heat loading with disruption mitigation by injection of a massive gas puff.

Wide-angle ITER-prototype tangential infrared and visible viewing system for DIII-D

DOE PAGES

Lasnier, Charles J.; Allen, Steve L.; Ellis, Ronald E.; ...

2014-08-26

An imaging system with a wide-angle tangential view of the full poloidal cross-section of the tokamak in simultaneous infrared and visible light has been installed on DIII-D. The optical train includes three polished stainless steel mirrors in vacuum, which view the tokamak through an aperture in the first mirror, similar to the design concept proposed for ITER. A dichroic beam splitter outside the vacuum separates visible and infrared (IR) light. Spatial calibration is accomplished by warping a CAD-rendered image to align with landmarks in a data image. The IR camera provides scrape-off layer heat flux profile deposition features in divertedmore » and inner-wall-limited plasmas, such as heat flux reduction in pumped radiative divertor shots. As a result, demonstration of the system to date includes observation of fast-ion losses to the outer wall during neutral beam injection, and shows reduced peak wall heat loading with disruption mitigation by injection of a massive gas puff.« less

Combined laser heating and tandem acousto-optical filter for two-dimensional temperature distribution on the surface of the heated microobject

NASA Astrophysics Data System (ADS)

Bykov, A. A.; Kutuza, I. B.; Zinin, P. V.; Machikhin, A. S.; Troyan, I. A.; Bulatov, K. M.; Batshev, V. I.; Mantrova, Y. V.; Gaponov, M. I.; Prakapenka, V. B.; Sharma, S. K.

2018-01-01

Recently it has been shown that it is possible to measure the two-dimensional distribution of the surface temperature of microscopic specimens. The main component of the system is a tandem imaging acousto-optical tunable filter synchronized with a video camera. In this report, we demonstrate that combining the laser heating system with a tandem imaging acousto-optical tunable filter allows measurement of the temperature distribution under laser heating of the platinum plates as well as a visualization of the infrared laser beam, that is widely used for laser heating in diamond anvil cells.

Gold and isotopically enriched platinium targets for the production of radioactive beams of francium

NASA Astrophysics Data System (ADS)

Lipski, A. R.; Orozco, L. A.; Pearson, M. R.; Simsarian, J. E.; Sprouse, G. D.; Zhao, W. Z.

1999-12-01

Au and isotopically enriched Pt targets are discussed for the production of radioactive Fr beams. Target foils, serving also as ionizers, have to be heated in order to enhance the diffusion of atoms to the surface for further extraction and injection into the electrostatic transport system.

Multi-Focus Beamforming for Thermal Strain Imaging Using a Single Ultrasound Linear Array Transducer.

PubMed

Nguyen, Man M; Ding, Xuan; Leers, Steven A; Kim, Kang

2017-06-01

Ultrasound-induced thermal strain imaging (TSI) has been used successfully to identify lipid- and water-based tissues in atherosclerotic plaques in some research settings. However, TSI faces several challenges to be realized in clinics. These challenges include motion artifacts and displacement tracking accuracy, as well as limited heating capability, which contributes to low thermal strain signal-to-noise ratio, and a limited field of view. Our goal was to address the challenge in heating tissue in TSI. Current TSI systems use separate heating and imaging transducers, which require physical alignment of the heating and imaging beams and result in a bulky setup that limits in vivo operation. We evaluated a new design for heating beams that can be implemented on a linear array imaging transducer and can provide improved heating area and efficiency as compared with previous implementations. The heating beams designed were implemented with a clinical linear array imaging transducer connected to a research ultrasound platform. In vitro experiments using tissue-mimicking phantoms with no blood flow revealed that the new design resulted in an effective heating area of approximately 0.85 cm 2 and a 0.3°C temperature rise in 2 s of heating, which compared well with in silico finite-element simulations. With the new heating beams, TSI was found to be able to detect a lipid-mimicking rubber inclusion with a diameter of 1 cm from the water-based gelatin background, with a strain contrast of 2.3 (+0.14% strain in the rubber inclusion and -0.06% strain in the gelatin background). Lastly, lipid-based tissue in a 1-cm-diameter human carotid endarterectomy (CEA) sample was identified in good agreement with histology. Copyright © 2017 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

"Twisted Beam" SEE Observations of Ionospheric Heating from HAARP

NASA Astrophysics Data System (ADS)

Briczinski, S. J.; Bernhardt, P. A.; Siefring, C. L.; Han, S.-M.; Pedersen, T. R.; Scales, W. A.

2015-10-01

Nonlinear interactions of high power HF radio waves in the ionosphere provide aeronomers with a unique space-based laboratory capability. The High-Frequency Active Auroral Research Program (HAARP) in Gakona, Alaska is the world's largest heating facility, yielding effective radiated powers in the gigawatt range. New results are present from HAARP experiments using a "twisted beam" excitation mode. Analysis of twisted beam heating shows that the SEE results obtained are identical to more traditional patterns. One difference in the twisted beam mode is the heating region produced is in the shape of a ring as opposed to the more traditional "solid spot" region from a pencil beam. The ring heating pattern may be more conducive to the creation of stable artificial airglow layers because of the horizontal structure of the ring. The results of these runs include artificial layer creation and evolution as pertaining to the twisted beam pattern. The SEE measurements aid the interpretation of the twisted beam interactions in the ionosphere.

The effect of weld stresses on weld quality. [stress fields and metal cracking

NASA Technical Reports Server (NTRS)

Chihoski, R. A.

1972-01-01

A narrow heat source raises the temperature of a spot on a solid piece of material like metal. The high temperature of the spot decreases with distance from the spot. This is true whether the heat source is an arc, a flame, an electron beam, a plasma jet, a laser beam, or any other source of intense, narrowly defined heat. Stress and strain fields around a moving heat source are organized into a coherent visible system. It is shown that five stresses act across the weld line in turn as an arc passes. Their proportions and positions are considerably altered by weld parameters or condition changes. These pushes and pulls affect the metallurgical character and integrity of the weld area even when there is no apparent difference between after-the-fact examples.

Development of bunch shape monitor for high-intensity beam on the China ADS proton LINAC Injector II

NASA Astrophysics Data System (ADS)

Zhu, Guangyu; Wu, Junxia; Du, Ze; Zhang, Yong; Xue, Zongheng; Xie, Hongming; Wei, Yuan; Jing, Long; Jia, Huan

2018-05-01

The development, performance, and testing of the longitudinal bunch shape monitor, namely, the Fast Faraday Cup (FFC), are presented in this paper. The FFC is an invasive instrument controlled by a stepper motor, and its principle of operation is based on a strip line structure. The longitudinal bunch shape was determined by sampling a small part of the beam hitting the strip line through a 1-mm hole. The rise time of the detector reached 24 ps. To accommodate experiments that utilize high-intensity beams, the materials of the bunch shape monitor were chosen to sustain high temperatures. Water cooling was also integrated in the detector system to enhance heat transfer and prevent thermal damage. We also present an analysis of the heating caused by the beam. The bunch shape monitor has been installed and commissioned at the China ADS proton LINAC Injector II.

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

NASA Astrophysics Data System (ADS)

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

2017-10-01

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

High current density sheet-like electron beam generator

NASA Astrophysics Data System (ADS)

Chow-Miller, Cora; Korevaar, Eric; Schuster, John

Sheet electron beams are very desirable for coupling to the evanescent waves in small millimeter wave slow-wave circuits to achieve higher powers. In particular, they are critical for operation of the free-electron-laser-like Orotron. The program was a systematic effort to establish a solid technology base for such a sheet-like electron emitter system that will facilitate the detailed studies of beam propagation stability. Specifically, the effort involved the design and test of a novel electron gun using Lanthanum hexaboride (LaB6) as the thermionic cathode material. Three sets of experiments were performed to measure beam propagation as a function of collector current, beam voltage, and heating power. The design demonstrated its reliability by delivering 386.5 hours of operation throughout the weeks of experimentation. In addition, the cathode survived two venting and pump down cycles without being poisoned or losing its emission characteristics. A current density of 10.7 A/sq cm. was measured while operating at 50 W of ohmic heating power. Preliminary results indicate that the nearby presence of a metal plate can stabilize the beam.

Laser beam shaping for studying thermally induced damage

NASA Astrophysics Data System (ADS)

Masina, Bathusile N.; Bodkin, Richard; Mwakikunga, Bonex; Forbes, Andrew

2011-10-01

This paper presents an implementation of a laser beam shaping system for both heating a diamond tool and measuring the resulting temperature optically. The influence the initial laser parameters have on the resultant temperature profiles is shown experimentally and theoretically. A CO2 laser beam was used as the source to raise the temperature of the diamond tool and the resultant temperature was measured by using the blackbody principle. We have successfully transformed a Gaussian beam profile into a flat-top beam profile by using a diffractive optical element as a phase element in conjunction with a Fourier transforming lens. In this paper, we have successfully demonstrated temperature profiles across the diamond tool surface using two laser beam profiles and two optical setups, thus allowing a study of temperature influences with and without thermal stress. The generation of such temperature profiles on the diamond tool in the laboratory is important in the study of changes that occur in diamond tools, particularly the reduced efficiency of such tools in applications where extreme heating due to friction is expected.

Development of an energy analyzer as diagnostic of beam-generated plasma in negative ion beam systems

NASA Astrophysics Data System (ADS)

Sartori, E.; Carozzi, G.; Veltri, P.; Spolaore, M.; Cavazzana, R.; Antoni, V.; Serianni, G.

2017-08-01

The measurement of the plasma potential and the energy spectrum of secondary particles in the drift region of a negative ion beam offers an insight into beam-induced plasma formation and beam transport in low pressure gasses. Plasma formation in negative-ion beam systems, and the characteristics of such a plasma are of interest especially for space charge compensation, plasma formation in neutralizers, and the development of improved schemes of beam-induced plasma neutralisers for future fusion devices. All these aspects have direct implications in the ITER Heating Neutral Beam and the operation of the prototypes, SPIDER and MITICA, and also have important role in the conceptual studies for NBI systems of DEMO, while at present experimental data are lacking. In this paper we present the design and development of an ion energy analyzer to measure the beam plasma formation and space charge compensation in negative ion beams. The diagnostic is a retarding field energy analyzer (RFEA), and will measure the transverse energy spectra of plasma molecular ions. The calculations that supported the design are reported, and a method to interpret the measurements in negative ion beam systems is also proposed. Finally, the experimental results of the first test in a magnetron plasma are presented.

New Submount Requirement of Conductively Cooled Laser Diodes for Lidar Applications

NASA Technical Reports Server (NTRS)

Mo, S. Y.; Cutler, A. D.; Choi, S. H.; Lee, M. H.; Singh, U. N.

2000-01-01

New submount technology is essential for the development of conductively cooled high power diode laser. The simulation and experimental results indicate that thermal conductivity of submount for high power laser-diode must be at least 600 W/m/k or higher for stable operation. We have simulated several theoretical thermal model based on new submount designs and characterized high power diode lasers to determine temperature effects on the performances of laser diodes. The characterization system measures the beam power, output beam profile, temperature distribution, and spectroscopic property of high power diode laser. The characterization system is composed of four main parts: an infrared imaging camera, a CCD camera, a monochromator, and a power meter. Thermal characteristics of two commercial-grade CW 20-W diode laser bars with open heat-sink type were determined with respect to the line shift of emission spectra and beam power stability. The center wavelength of laser emission has a tendency to shift toward longer wavelength as the driving current and heat sink temperature are increased. The increase of heat sink temperature decreases the output power of the laser bar too. Such results lay the guidelines for the design of new submount for high power laser-diodes.

Annual Summary Report on Thermionic Cathode Project.

DTIC Science & Technology

1986-01-09

Voltage Operation The electron gun cathode is driven negative by a high voltageRadiation pulse modulator in the circuit of Figure 3-1. Typical current...tungsten filament. The bombardment heating system is stabilized by a feed- back control circuit . The power required to heat tne cathode is 315 W bom...project. The primary purpose of the first phase was to develop the bombardment heating circuit used to heat the LaB 6 cathode, and to test the beam

Collisionless effects on beam-return current systems in solar flares

NASA Technical Reports Server (NTRS)

Vlahos, L.; Rowland, H. L.

1985-01-01

A theoretical study of the beam-return current system (BRCS) in solar flares shows that the precipitating electrons modify the way in which the return current (RC) is carried by the background plasma. In particular it is found that the RC is not carried by the bulk of the electrons but by a small number of high-velocity electrons. For beam/plasma densities exceeding approximately 0.001, this can reduce the effects of collisions and heating by the RC. For higher-density beams, where the RC could be unstable to current-driven instabilities, the effects of strong turbulence anomalous resistivity prevent the appearance of such instabilities. The main conclusion is that the BRCS is interconnected, and that the beam-generated strong turbulence determines how the RC is carried.

Patterning of ultrathin polymethylmethacrylate films by in-situ photodirecting of the Marangoni flow

NASA Astrophysics Data System (ADS)

Elashnikov, Roman; Fitl, Premysl; Svorcik, Vaclav; Lyutakov, Oleksiy

2017-02-01

Laser heating and Marangoni flow result in the formation of surface structures with different geometries and shape on thin polymer films. By laser beam irradiation combined with a sample movement the solid polymethylmethacrylate (PMMA) films are heated and undergo phase transition which leads to a material flow. Since the laser beam has a non-linear distribution of energy, the PMMA film is heated inhomogeneously and a surface tension gradient in a lateral direction is introduced. During this procedure additional phenomena such as "reversible" or cyclic polymer flow also take place. The careful choice of experimental conditions enables the preparation of patterns with sophisticated geometries and with hierarchical pattern organization. Depending on initial PMMA film thickness and speed of the sample movement line arrays are created, which can subsequently be transformed into the crimped lines or system of circular holes. In addition, the introduction of a constant acceleration in the sample movement or a laser beam distortion enables the preparation of regularly crimped lines, ordered hexagonal holes or overlapped plates.

Design of a New Acceleration System for High-Current Pulsed Proton Beams from an ECR Source

NASA Astrophysics Data System (ADS)

Cooper, Andrew L.; Pogrebnyak, Ivan; Surbrook, Jason T.; Kelly, Keegan J.; Carlin, Bret P.; Champagne, Arthur E.; Clegg, Thomas B.

2014-03-01

A primary objective for accelerators at TUNL's Laboratory for Experimental Nuclear Astrophysics (LENA) is to maximize target beam intensity to ensure a high rate of nuclear events during each experiment. Average proton target currents of several mA are needed from LENA's electron cyclotron resonance (ECR) ion source because nuclear cross sections decrease substantially at energies of interest <200 keV. We seek to suppress undesired continuous environmental background by pulsing the beam and detecting events only during beam pulses. To improve beam intensity and transport, we installed a more powerful, stable microwave system for the ECR plasma, and will install a new acceleration system. This system will: reduce defocusing effects of the beam's internal space charge; provide better vacuum with a high gas conductance accelerating column; suppress bremsstrahlung X-rays produced when backstreaming electrons strike internal acceleration tube structures; and provide better heat dissipation by using deionized water to provide the current drain needed to establish the accelerating tube's voltage gradient. Details of beam optical modeling calculations, proposed accelerating tube design, and initial beam pulsing tests will be described. Work supported in part by USDOE Office of HE and Nuclear Physics.

Note: A component-level frequency tunable isolator for vibration-sensitive chips using SMA beams.

PubMed

Zhang, Xiaoyong; Ding, Xin; Wu, Di; Qi, Junlei; Wang, Ruixin; Lu, Siwei; Yan, Xiaojun

2016-06-01

This note presents a component-level frequency tunable isolator for vibration-sensitive chips. The isolator employed 8 U-shaped shape memory alloy (SMA) beams to support an isolation island (used for mounting chips). Due to the temperature-induced Young's modulus variation of SMA, the system stiffness of the isolator can be controlled through heating the SMA beams. In such a way, the natural frequency of the isolator can be tuned. A prototype was fabricated to evaluate the concept. The test results show that the natural frequency of the isolator can be tuned in the range of 64 Hz-97 Hz by applying different heating strategies. Moreover, resonant vibration can be suppressed significantly (the transmissibility decreases about 65% near the resonant frequency) using a real-time tuning method.

Thermal modeling of head disk interface system in heat assisted magnetic recording

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vemuri, Sesha Hari; Seung Chung, Pil; Jhon, Myung S., E-mail: mj3a@andrew.cmu.edu

2014-05-07

A thorough understanding of the temperature profiles introduced by the heat assisted magnetic recording is required to maintain the hotspot at the desired location on the disk with minimal heat damage to other components. Here, we implement a transient mesoscale modeling methodology termed lattice Boltzmann method (LBM) for phonons (which are primary carriers of energy) in the thermal modeling of the head disk interface (HDI) components, namely, carbon overcoat (COC). The LBM can provide more accurate results compared to conventional Fourier methodology by capturing the nanoscale phenomena due to ballistic heat transfer. We examine the in-plane and out-of-plane heat transfermore » in the COC via analyzing the temperature profiles with a continuously focused and pulsed laser beam on a moving disk. Larger in-plane hotspot widening is observed in continuously focused laser beam compared to a pulsed laser. A pulsed laser surface develops steeper temperature gradients compared to continuous hotspot. Furthermore, out-of-plane heat transfer from the COC to the media is enhanced with a continuous laser beam then a pulsed laser, while the temperature takes around 140 fs to reach the bottom surface of the COC. Our study can lead to a realistic thermal model describing novel HDI material design criteria for the next generation of hard disk drives with ultra high recording densities.« less

Correlation of predicted and measured thermal stresses on an advanced aircraft structure with similar materials

NASA Technical Reports Server (NTRS)

Jenkins, J. M.

1979-01-01

A laboratory heating test simulating hypersonic heating was conducted on a heat-sink type structure to provide basic thermal stress measurements. Six NASTRAN models utilizing various combinations of bar, shear panel, membrane, and plate elements were used to develop calculated thermal stresses. Thermal stresses were also calculated using a beam model. For a given temperature distribution there was very little variation in NASTRAN calculated thermal stresses when element types were interchanged for a given grid system. Thermal stresses calculated for the beam model compared similarly to the values obtained for the NASTRAN models. Calculated thermal stresses compared generally well to laboratory measured thermal stresses. A discrepancy of signifiance occurred between the measured and predicted thermal stresses in the skin areas. A minor anomaly in the laboratory skin heating uniformity resulted in inadequate temperature input data for the structural models.

X-ray analysis of electron Bernstein wave heating in MST

DOE Office of Scientific and Technical Information (OSTI.GOV)

Seltzman, A. H., E-mail: seltzman@wisc.edu; Anderson, J. K.; DuBois, A. M.

2016-11-15

A pulse height analyzing x-ray tomography system has been developed to detect x-rays from electron Bernstein wave heated electrons in the Madison symmetric torus reversed field pinch (RFP). Cadmium zinc telluride detectors are arranged in a parallel beam array with two orthogonal multi-chord detectors that may be used for tomography. In addition a repositionable 16 channel fan beam camera with a 55° field of view is used to augment data collected with the Hard X-ray array. The chord integrated signals identify target emission from RF heated electrons striking a limiter located 12° toroidally away from the RF injection port. Thismore » provides information on heated electron spectrum, transport, and diffusion. RF induced x-ray emission from absorption on harmonic electron cyclotron resonances in low current (<250 kA) RFP discharges has been observed.« less

Status of the 1 MeV Accelerator Design for ITER NBI

NASA Astrophysics Data System (ADS)

Kuriyama, M.; Boilson, D.; Hemsworth, R.; Svensson, L.; Graceffa, J.; Schunke, B.; Decamps, H.; Tanaka, M.; Bonicelli, T.; Masiello, A.; Bigi, M.; Chitarin, G.; Luchetta, A.; Marcuzzi, D.; Pasqualotto, R.; Pomaro, N.; Serianni, G.; Sonato, P.; Toigo, V.; Zaccaria, P.; Kraus, W.; Franzen, P.; Heinemann, B.; Inoue, T.; Watanabe, K.; Kashiwagi, M.; Taniguchi, M.; Tobari, H.; De Esch, H.

2011-09-01

The beam source of neutral beam heating/current drive system for ITER is needed to accelerate the negative ion beam of 40A with D- at 1 MeV for 3600 sec. In order to realize the beam source, design and R&D works are being developed in many institutions under the coordination of ITER organization. The development of the key issues of the ion source including source plasma uniformity, suppression of co-extracted electron in D beam operation and also after the long beam duration time of over a few 100 sec, is progressed mainly in IPP with the facilities of BATMAN, MANITU and RADI. In the near future, ELISE, that will be tested the half size of the ITER ion source, will start the operation in 2011, and then SPIDER, which demonstrates negative ion production and extraction with the same size and same structure as the ITER ion source, will start the operation in 2014 as part of the NBTF. The development of the accelerator is progressed mainly in JAEA with the MeV test facility, and also the computer simulation of beam optics also developed in JAEA, CEA and RFX. The full ITER heating and current drive beam performance will be demonstrated in MITICA, which will start operation in 2016 as part of the NBTF.

Radial Distribution of Absorption in a Cesium Heat Pipe with Axial Laser Heating

DTIC Science & Technology

2011-03-01

The spring is used to maintain a clear circular path through the heat pipe and secure the mesh. Two copper crush gaskets attach the Brewster angled ...necessary. The pump beam is assumed to be a Gaussian beam and has been focused through a convex lens to position the beam waist at the center of

Laser fusion neutron source employing compression with short pulse lasers

DOEpatents

Sefcik, Joseph A; Wilks, Scott C

2013-11-05

A method and system for achieving fusion is provided. The method includes providing laser source that generates a laser beam and a target that includes a capsule embedded in the target and filled with DT gas. The laser beam is directed at the target. The laser beam helps create an electron beam within the target. The electron beam heats the capsule, the DT gas, and the area surrounding the capsule. At a certain point equilibrium is reached. At the equilibrium point, the capsule implodes and generates enough pressure on the DT gas to ignite the DT gas and fuse the DT gas nuclei.

First experimental demonstration of magnetic-field assisted fast heating of a dense plasma core

NASA Astrophysics Data System (ADS)

Fujioka, Shinsuke; Sakata, Shohei; Lee, Seung Ho; Matsuo, Kazuki; Sawada, Hiroshi; Iwasa, Yuki; Law, King Fai Farley; Morita, Hitoki; Kojima, Sadaoki; Abe, Yuki; Yao, Akira; Hata, Masayasu; Johzaki, Tomoyuki; Sunahara, Atsushi; Ozaki, Tetsuo; Sakagami, Hitoshi; Morace, Alessio; Arikawa, Yasunobu; Yogo, Akifumi; Nishimura, Hiroaki; Nakai, Mitsuo; Shiraga, Hiroyuki; Sentoku, Yasuhiko; Nagatomo, Hideo; Azechi, Hiroshi; Firex Project Team

2016-10-01

Fast heating of a dense plasma core by an energetic electron beam is being studied on GEKKO-LFEX laser facility. Here, we introduce a laser-driven kilo-tesla external magnetic field to guide the diverging electron beam to the dense plasma core. This involve placing a spherical target in the magnetic field, compressing it with the GEKKO-XII laser beams and then using the LFEX laser beams injected into the dense plasma to generate the electron beam which do the fast heating. Cu-Ka emission is used to visualize transport or heating processes of a dense plasma. X-ray spectrum from a highly ionized Cu ions indicates several keV of the temperature increment induced by the LFEX.

Applications of power beaming from space-based nuclear power stations. [Laser beaming to airplanes; microwave beaming to ground

DOE Office of Scientific and Technical Information (OSTI.GOV)

Powell, J.R.; Botts, T.E.; Hertzberg, A.

1981-01-01

Power beaming from space-based reactor systems is examined using an advanced compact, lightweight Rotating Bed Reactor (RBR). Closed Brayton power conversion efficiencies in the range of 30 to 40% can be achieved with turbines, with reactor exit temperatures on the order of 2000/sup 0/K and a liquid drop radiator to reject heat at temperatures of approx. 500/sup 0/K. Higher RBR coolant temperatures (up to approx. 3000/sup 0/K) are possible, but gains in power conversion efficiency are minimal, due to lower expander efficiency (e.g., a MHD generator). Two power beaming applications are examined - laser beaming to airplanes and microwave beamingmore » to fixed ground receivers. Use of the RBR greatly reduces system weight and cost, as compared to solar power sources. Payback times are a few years at present prices for power and airplane fuel.« less

Laser addressed holographic memory system

NASA Technical Reports Server (NTRS)

Gange, R. A.; Wagle, E. M.; Steinmetz, C. C.

1973-01-01

Holographic recall and storage system uses red-lipid microcrystalline wax as storage medium. When laser beam strikes wax, its energy heats point of incidence enough to pass wax through transition temperature. Holograph image can then be written or erased in softened wax.

Electron Bernstein Wave Emission Studies on the TJ-II Stellarator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Caughman, John B; Fernandez, A.; Cappa, A.

2009-01-01

Electron Bernstein Wave (EBW) heating is important for high-beta plasma experiments and will be used for heating over-dense plasmas on TJ-II. TJ-II is a medium sized Heliac operating at CIEMAT in Madrid, whose plasmas are created and heated by ECH via two 300 kW gyrotrons at second harmonic X-mode (53.2 GHz), with additional heating provided by two neutral beam injectors. Theoretical work has shown that the most suitable scheme for launching EBWs in TJ-II is O-X-B mode conversion, which has acceptable heating efficiency for central densities above 1.2 x 1019 m-3.[1] A system based on a 28 GHz-100ms diode gyrotronmore » will be used to deliver 300 kW through a corrugated waveguide. The microwave heating beam will be directed and focused by a steering mirror located inside the vacuum vessel. Prior to the heating experiments, measurement of the thermal EBW emission (EBE) from the plasma is being made to help determine the optimum launch angle for EBW mode conversion, and also to provide an indication of the electron temperature evolution in over-dense plasmas. A dual-polarized quad-ridged broadband horn is used to measure the EBW emission and polarization at 28 GHz. Initial measurements indicate that the emission in under-dense plasmas corresponds to oblique electron cyclotron emission (ECE) and then converts to EBE when the plasma becomes over-dense during neutral beam injection.« less

Indirect Versus Direct Heating of Sheet Materials: Superplastic Forming and Diffusion Bonding Using Lasers

NASA Astrophysics Data System (ADS)

Jocelyn, Alan; Kar, Aravinda; Fanourakis, Alexander; Flower, Terence; Ackerman, Mike; Keevil, Allen; Way, Jerome

2010-06-01

Many from within manufacturing industry consider superplastic forming (SPF) to be ‘high tech’, but it is often criticized as too complicated, expensive, slow and, in general, an unstable process when compared to other methods of manipulating sheet materials. Perhaps, the fundamental cause of this negative perception of SPF, and also of diffusion bonding (DB), is the fact that the current process of SPF/DB relies on indirect sources of heating to produce the conditions necessary for the material to be formed. Thus, heat is usually derived from the electrically heated platens of hydraulic presses, to a lesser extent from within furnaces and, sometimes, from heaters imbedded in ceramic moulds. Recent evaluations of these isothermal methods suggest they are slow, thermally inefficient and inappropriate for the process. In contrast, direct heating of only the material to be formed by modern, electrically efficient, lasers could transform SPF/DB into the first choice of designers in aerospace, automotive, marine, medical, architecture and leisure industries. Furthermore, ‘variable temperature’ direct heating which, in theory, is possible with a laser beam(s) may provide a means to control material thickness distribution, a goal of enormous importance as fuel efficient, lightweight structures for transportation systems are universally sought. This paper compares, and contrasts, the two systems and suggests how a change to laser heating might be achieved.

Heating and current drive on NSTX

NASA Astrophysics Data System (ADS)

Wilson, J. R.; Batchelor, D.; Carter, M.; Hosea, J.; Ignat, D.; LeBlanc, B.; Majeski, R.; Ono, M.; Phillips, C. K.; Rogers, J. H.; Schilling, G.

1997-04-01

Low aspect ratio tokamaks pose interesting new challenges for heating and current drive. The NSTX (National Spherical Tokamak Experiment) device to be built at Princeton is a low aspect ratio toroidal device that has the achievement of high toroidal beta (˜45%) and non-inductive operation as two of its main research goals. To achieve these goals significant auxiliary heating and current drive systems are required. Present plans include ECH (Electron cyclotron heating) for pre-ionization and start-up assist, HHFW (high harmonic fast wave) for heating and current drive and eventually NBI (neutral beam injection) for heating, current drive and plasma rotation.

Demonstration of Efficient Core Heating of Magnetized Fast Ignition in FIREX project

NASA Astrophysics Data System (ADS)

Johzaki, Tomoyuki

2017-10-01

Extensive theoretical and experimental research in the FIREX ``I project over the past decade revealed that the large angular divergence of the laser generated electron beam is one of the most critical problems inhibiting efficient core heating in electron-driven fast ignition. To solve this problem, beam guiding using externally applied kilo-tesla class magnetic field was proposed, and its feasibility has recently been numerically demonstrated. In 2016, integrated experiments at ILE Osaka University demonstrated core heating efficiencies reaching > 5 % and heated core temperatures of 1.7 keV. In these experiments, a kilo-tesla class magnetic field was applied to a cone-attached Cu(II) oleate spherical solid target by using a laser-driven capacitor-coil. The target was then imploded by G-XII laser and heated by the PW-class LFEX laser. The heating efficiency was evaluated by measuring the number of Cu-K- α photons emitted. The heated core temperature was estimated by the X-ray intensity ratio of Cu Li-like and He-like emission lines. To understand the detailed dynamics of the core heating process, we carried out integrated simulations using the FI3 code system. Effects of magnetic fields on the implosion and electron beam transport, detailed core heating dynamics, and the resultant heating efficiency and core temperature will be presented. I will also discuss the prospect for an ignition-scale design of magnetized fast ignition using a solid ball target. This work is partially supported by JSPA KAKENHI Grant Number JP16H02245, JP26400532, JP15K21767, JP26400532, JP16K05638 and is performed with the support and the auspices of the NIFS Collaboration Research program (NIFS12KUGK057, NIFS15KUGK087).

Uniform heating of materials into the warm dense matter regime with laser-driven quasimonoenergetic ion beams

NASA Astrophysics Data System (ADS)

Bang, W.; Albright, B. J.; Bradley, P. A.; Vold, E. L.; Boettger, J. C.; Fernández, J. C.

2015-12-01

In a recent experiment at the Trident laser facility, a laser-driven beam of quasimonoenergetic aluminum ions was used to heat solid gold and diamond foils isochorically to 5.5 and 1.7 eV, respectively. Here theoretical calculations are presented that suggest the gold and diamond were heated uniformly by these laser-driven ion beams. According to calculations and SESAME equation-of-state tables, laser-driven aluminum ion beams achievable at Trident, with a finite energy spread of ΔE /E ˜20 %, are expected to heat the targets more uniformly than a beam of 140-MeV aluminum ions with zero energy spread. The robustness of the expected heating uniformity relative to the changes in the incident ion energy spectra is evaluated, and expected plasma temperatures of various target materials achievable with the current experimental platform are presented.

Walking beam furnace well-way slot covers at Rouge Steel

DOE Office of Scientific and Technical Information (OSTI.GOV)

Campbell, F. Jr.; Meinzinger, A.D.; Faust, C.H.

1993-07-01

Rouge Steel's 68-in. hot strip mill is served by three walking beam slab reheat furnaces. The first two were commissioned in 1974 and the third was installed in 1980. During the period 1979 to 1981, an intensive plant-wide energy management program to reduce energy consumption was undertaken. A major part of that program involved a comprehensive upgrading of refractory and insulation systems utilized in the walking beam reheat furnaces. A durable system for reducing heat losses through the well-way floor openings associated with walking beam slab reheat furnaces has, in addition to 4 to 5% savings in fuel consumption, reducedmore » maintenance costs. Payback is achieved in four to five months.« less

Design and performance of vacuum system for high heat flux test facility

NASA Astrophysics Data System (ADS)

Swamy Kidambi, Rajamannar; Mokaria, Prakash; Khirwadkar, Samir; Belsare, Sunil; Khan, M. S.; Patel, Tushar; Krishnan, Deepu S.

2017-04-01

High heat flux test facility (HHFTF) at IPR is used for testing thermal performance of plasma facing materials or components. It consists of various subsystems like vacuum system, high power electron beam system, diagnostic and calibration system, data acquisition and control system and high pressure high temperature water circulation system. Vacuum system consists of large D-shaped chamber, target handling system, pumping systems and support structure. The net volume of vacuum chamber is 5 m3 was maintained at the base pressure of the order of 10-6 mbar for operation of electron gun with minimum beam diameter which is achieved with turbo-molecular pump (TMP) and cryo pump. A variable conductance gate valve is used for maintaining required vacuum in the chamber. Initial pumping of the chamber was carried out by using suitable rotary and root pumps. PXI and PLC based faster real time data acquisition and control system is implemented for performing the various operations like remote operation, online vacuum data measurements, display and status indication of all vacuum equipments. This paper describes in detail the design and implementation of various vacuum system for HHFTF.

Diagnostics of the ITER neutral beam test facility.

PubMed

Pasqualotto, R; Serianni, G; Sonato, P; Agostini, M; Brombin, M; Croci, G; Dalla Palma, M; De Muri, M; Gazza, E; Gorini, G; Pomaro, N; Rizzolo, A; Spolaore, M; Zaniol, B

2012-02-01

The ITER heating neutral beam (HNB) injector, based on negative ions accelerated at 1 MV, will be tested and optimized in the SPIDER source and MITICA full injector prototypes, using a set of diagnostics not available on the ITER HNB. The RF source, where the H(-)∕D(-) production is enhanced by cesium evaporation, will be monitored with thermocouples, electrostatic probes, optical emission spectroscopy, cavity ring down, and laser absorption spectroscopy. The beam is analyzed by cooling water calorimetry, a short pulse instrumented calorimeter, beam emission spectroscopy, visible tomography, and neutron imaging. Design of the diagnostic systems is presented.

Heat trap - An optimized far infrared field optics system. [for astronomical sources

NASA Technical Reports Server (NTRS)

Harper, D. A.; Hildebrand, R. H.; Winston, R.; Stiening, R.

1976-01-01

The article deals with the design and performance of a heat trap IR system designed to maximize the concentration and efficient reception of far IR and submillimeter wavelength radiation. The test object is assumed to be extended and/or viewed at wavelengths much longer than the detector, and the entrance aperture is limited to the size of the telescope Airy diffraction disk. The design of lenses, cavity, bolometers, light collectors, and mirrors for the system is discussed. Advantages and feasibility of arrays of heat traps are considered. Beam patterns, flux concentration, and performance variation with wavelength are dealt with. The heat trap is recommended for sensing all types of far IR sources and particularly for extended far IR sources.-

Development of movable mask system to cope with high beam current

NASA Astrophysics Data System (ADS)

Suetsugu, Y.; Shibata, K.; Sanami, T.; Kageyama, T.; Takeuchi, Y.

2003-07-01

The KEK B factory (KEKB), a high current electron-positron collider, has a movable mask (or collimator) system to reduce the background noise in the BELLE detector coming from spent particles. The early movable masks, however, had severe problems of heating, arcing, and vacuum leaks over the stored beam current of several hundred mA. The cause is intense trapped higher order modes (HOMs) excited at the mask head, where the cross section of the beam chamber changed drastically. The mask head, made of copper-tungsten alloy or pure copper, was frequently damaged by hitting of the high energy beam at the same time. Since the problems of the mask were revealed, several kinds of improved masks have been designed employing rf technologies in dealing with the HOM and installed to the ring step by step. Much progress has come from adopting a trapped-mode free structure, where the mask was a bent chamber itself. Recently the further improved mask with a reduced HOM design or HOM dampers was developed to suppress the heating of vacuum components near the mask due to the HOM traveling from the mask. To avoid damage to the mask head, on the other hand, a titanium mask head was tried. The latest masks are working as expected now at the stored beam current of 1.5 A. Presented are the problems and experiences on the movable mask system for the KEKB, which are characteristic of and common in a high intensity accelerator.

Direct heating of a laser-imploded core using ultraintense laser LFEX

NASA Astrophysics Data System (ADS)

Kitagawa, Y.; Mori, Y.; Ishii, K.; Hanayama, R.; Nishimura, Y.; Okihara, S.; Nakayama, S.; Sekine, T.; Takagi, M.; Watari, T.; Satoh, N.; Kawashima, T.; Komeda, O.; Hioki, T.; Motohiro, T.; Azuma, H.; Sunahara, A.; Sentoku, Y.; Arikawa, Y.; Abe, Y.; Miura, E.; Ozaki, T.

2017-07-01

A CD shell was preimploded by two counter-propagating green beams from the GEKKO laser system GXII (based at the Institute of Laser Engineering, Osaka University), forming a dense core. The core was predominantly heated by energetic ions driven by the laser for fast-ignition-fusion experiment, an extremely energetic ultrashort pulse laser, that is illuminated perpendicularly to the GXII axis. Consequently, we observed the D(d, n)3 He-reacted neutrons (DD beam-fusion neutrons) at a yield of 5× {{10}8} n/4π sr. The beam-fusion neutrons verified that the ions directly collided with the core plasma. Whereas the hot electrons heated the whole core volume, the energetic ions deposited their energies locally in the core. As evidenced in the spectrum, the process simultaneously excited thermal neutrons with a yield of 6× {{10}7} n/4π sr, raising the local core temperature from 0.8 to 1.8 keV. The shell-implosion dynamics (including the beam fusion and thermal fusion initiated by fast deuterons and carbon ions) can be explained by the one-dimensional hydrocode STAR 1D. Meanwhile, the core heating due to resistive processes driven by hot electrons, and also the generation of fast ions were well-predicted by the two-dimensional collisional particle-in-cell code. Together with hot electrons, the ion contribution to fast ignition is indispensable for realizing high-gain fusion. By virtue of its core heating and ignition, the proposed scheme can potentially achieve high-gain fusion.

Main improvements of LHC Cryogenics Operation during Run 2 (2015-2018)

NASA Astrophysics Data System (ADS)

Delprat, L.; Bradu, B.; Brodzinski, K.; Ferlin, G.; Hafi, K.; Herblin, L.; Rogez, E.; Suraci, A.

2017-12-01

After the successful Run 1 (2010-2012), the LHC entered its first Long Shutdown period (LS1, 2013-2014). During LS1 the LHC cryogenic system went under a complete maintenance and consolidation program. The LHC resumed operation in 2015 with an increased beam energy from 4 TeV to 6.5 TeV. Prior to the new physics Run 2 (2015-2018), the LHC was progressively cooled down from ambient to the 1.9 K operation temperature. The LHC has resumed operation with beams in April 2015. Operational margins on the cryogenic capacity were reduced compared to Run 1, mainly due to the observed higher than expected electron-cloud heat load coming from increased beam energy and intensity. Maintaining and improving the cryogenic availability level required the implementation of a series of actions in order to deal with the observed heat loads. This paper describes the results from the process optimization and update of the control system, thus allowing the adjustment of the non-isothermal heat load at 4.5 - 20 K and the optimized dynamic behaviour of the cryogenic system versus the electron-cloud thermal load. Effects from the new regulation settings applied for operation on the electrical distribution feed-boxes and inner triplets will be discussed. The efficiency of the preventive and corrective maintenance, as well as the benefits and issues of the present cryogenic system configuration for Run 2 operational scenario will be described. Finally, the overall availability results and helium management of the LHC cryogenic system during the 2015-2016 operational period will be presented.

Design and test of the RHIC CMD10 abort kicker

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hahn, H.; Blaskiewicz, M.; Drees, A.

2015-05-03

In recent RHIC operational runs, planned and unplanned pre-fire triggered beam aborts have been observed that resulted in quenches of SC main ring magnets, indicating a weakened magnet kick strength due to beam-induced ferrite heating. An improvement program was initiated to reduce the longitudinal coupling impedance with changes to the ferrite material and the eddy-current strip geometry. Results of the impedance measurements and of magnet heating tests with CMD10 ferrite up to 190°C are reported. All 10 abort kickers in the tunnel have been modified and were provided with a cooling system for the RUN 15.

Simulation Approach for Microscale Noncontinuum Gas-Phase Heat Transfer

NASA Astrophysics Data System (ADS)

Torczynski, J. R.; Gallis, M. A.

2008-11-01

In microscale thermal actuators, gas-phase heat transfer from the heated beams to the adjacent unheated substrate is often the main energy-loss mechanism. Since the beam-substrate gap is comparable to the molecular mean free path, noncontinuum gas effects are important. A simulation approach is presented in which gas-phase heat transfer is described by Fourier's law in the bulk gas and by a wall boundary condition that equates the normal heat flux to the product of the gas-solid temperature difference and a heat transfer coefficient. The dimensionless parameters in this heat transfer coefficient are determined by comparison to Direct Simulation Monte Carlo (DSMC) results for heat transfer from beams of rectangular cross section to the substrate at free-molecular to near-continuum gas pressures. This simulation approach produces reasonably accurate gas-phase heat-transfer results for wide ranges of beam geometries and gas pressures. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

Performance Characterization of the Production Facility Prototype Helium Flow System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Woloshun, Keith Albert; Dale, Gregory E.; Dalmas, Dale Allen

2015-12-16

The roots blower in use at ANL for in-beam experiments and also at LANL for flow tests was sized for 12 mm diameter disks and significantly less beam heating. Currently, the disks are 29 mm in diameter, with a 12 mm FWHM Gaussian beam spot at 42 MeV and 2.86 μA on each side of the target, 5.72 μA total. The target design itself is reported elsewhere. With the increased beam heating, the helium flow requirement increased so that a larger blower was need for a mass flow rate of 400 g/s at 2.76 MPa (400 psig). An Aerzen GMmore » 12.4 blower was selected, and is currently being installed at the LANL facility for target and component flow testing. This report describes this blower/motor/pressure vessel package and the status of the facility preparations. Blower performance (mass flow rate as a function of loop pressure drop) was measured at 4 blower speeds. Results are reported below.« less

Laser aircraft. [using kerosene

NASA Technical Reports Server (NTRS)

Hertzberg, A.; Sun, K.; Jones, W. S.

1979-01-01

The concept of a laser-powered aircraft is discussed. Laser flight would be completely compatible with existing airports and air-traffic control, with the airplane using kerosene only power, up to a cruising altitude of 9 km where the laser satellite would lock on and beam laser energy to it. Two major components make up the laser turbofan, a heat exchanger for converting laser radiation into thermal energy, and conventional turbomachinery. The laser power satellite would put out 42 Mw using a solar-powered thermal engine to generate electrical power for the closed-cycle supersonic electric discharge CO laser, whose radiators, heat exchangers, supersonic diffuser, and ducting will amount to 85% of the total subsystem mass. Relay satellites will be used to intercept the beam from the laser satellite, correct outgoing beam aberrations, and direct the beam to the next target. A 300-airplane fleet with transcontinental range is projected to save enough kerosene to equal the energy content of the entire system, including power and relay satellites, in one year.

Protons and alpha particles in the expanding solar wind: Hybrid simulations

NASA Astrophysics Data System (ADS)

Hellinger, Petr; Trávníček, Pavel M.

2013-09-01

We present results of a two‒dimensional hybrid expanding box simulation of a plasma system with three ion populations, beam and core protons, and alpha particles (and fluid electrons), drifting with respect to each other. The expansion with a strictly radial magnetic field leads to a decrease of the ion perpendicular to parallel temperature ratios as well as to an increase of the ratio between the ion relative velocities and the local Alfvén velocity creating a free energy for many different instabilities. The system is most of the time marginally stable with respect to kinetic instabilities mainly due to the ion relative velocities; these instabilities determine the system evolution counteracting some effects of the expansion. Nonlinear evolution of these instabilities leads to large modifications of the ion velocity distribution functions. The beam protons and alpha particles are decelerated with respect to the core protons and all the populations are cooled in the parallel direction and heated in the perpendicular one. On the macroscopic level, the kinetic instabilities cause large departures of the system evolution from the double adiabatic prediction and lead to perpendicular heating and parallel cooling rates which are comparable to the heating rates estimated from the Helios observations.

Single-jet gas cooling of in-beam foils or specimens: Prediction of the convective heat-transfer coefficient

NASA Astrophysics Data System (ADS)

Steyn, Gideon; Vermeulen, Christiaan

2018-05-01

An experiment was designed to study the effect of the jet direction on convective heat-transfer coefficients in single-jet gas cooling of a small heated surface, such as typically induced by an accelerated ion beam on a thin foil or specimen. The hot spot was provided using a small electrically heated plate. Heat-transfer calculations were performed using simple empirical methods based on dimensional analysis as well as by means of an advanced computational fluid dynamics (CFD) code. The results provide an explanation for the observed turbulent cooling of a double-foil, Havar beam window with fast-flowing helium, located on a target station for radionuclide production with a 66 MeV proton beam at a cyclotron facility.

JPRS report: Science and technology. Central Eurasia

NASA Astrophysics Data System (ADS)

1995-02-01

Translated articles cover the following topics: laser-controlled rotary microwave waveguide junction; optical pulse-phase modulation of semiconductor laser; amplitude-phase distortions of light beam obliquely propagating through ground layer of troposphere; antenna arrays with ultrafast beam scanning; materials for a walk on moon; textile-wood-coal briquette path to capitalism; and development of automated system for scientific research and design of heat and mass transfer processes.

Target diagnostics for commissioning the AWE HELEN Laser Facility 100 TW chirped pulse amplification beam

DOE Office of Scientific and Technical Information (OSTI.GOV)

Eagleton, R. T.; Clark, E. L.; Davies, H. M.

2006-10-15

The capability of the HELEN laser at the Atomic Weapons Establishment Aldermaston has been enhanced by the addition of a short-pulse laser beam to augment the twin opposing nanosecond time scale beams. The short-pulse beam utilizes the chirped pulse amplification (CPA) technique and is capable of delivering up to 60 J on target in a 500 fs pulse, around 100 TW, at the fundamental laser wavelength of 1.054 {mu}m. During the commissioning phase a number of diagnostic systems have been fielded, these include: x-ray pinhole imaging of the laser heated spot, charged particle time of flight, thermoluminescent dosimeter array, calibratedmore » radiochromic film, and CR39 nuclear track detector. These diagnostic systems have been used to verify the performance of the CPA beam to achieve a focused intensity of around 10{sup 19} W cm{sup -2} and to underwrite the facility radiological safety system.« less

High current proton beams production at Simple Mirror Ion Source 37.

PubMed

Skalyga, V; Izotov, I; Razin, S; Sidorov, A; Golubev, S; Kalvas, T; Koivisto, H; Tarvainen, O

2014-02-01

This paper presents the latest results of high current proton beam production at Simple Mirror Ion Source (SMIS) 37 facility at the Institute of Applied Physics (IAP RAS). In this experimental setup, the plasma is created and the electrons are heated by 37.5 GHz gyrotron radiation with power up to 100 kW in a simple mirror trap fulfilling the ECR condition. Latest experiments at SMIS 37 were performed using a single-aperture two-electrode extraction system. Proton beams with currents up to 450 mA at high voltages below 45 kV were obtained. The maximum beam current density was measured to be 600 mA/cm(2). A possibility of further improvement through the development of an advanced extraction system is discussed.

Ionosphere/microwave beam interaction study. [satellite solar energy conversion

NASA Technical Reports Server (NTRS)

Duncan, L. M.; Gordon, W. E.

1977-01-01

A solar power satellite microwave power density of 20mw sq cm was confirmed as the level where nonlinear interactions may occur in the ionosphere, particularly at 100 km altitude. Radio wave heating at this altitude, produced at the Arecibo Observatory, yielded negative results for radio wave heating of an underdense ionosphere. Overdense heating produced striations in the ionosphere which may cause severe radio frequency interference problems under certain conditions. The effects of thermal self-focusing are shown to be limited severely geographically. The aspect sensitivity of field-aligned striations makes interference-free regions above magnetic latitude about 60 deg. A test program is proposed to simulate the interaction of the SPS beam with the ionosphere, to measure the effects of the interaction on the ionosphere and on communication and navigation systems, and to interpret the results.

Anatomy of a cosmic-ray neutrino source and the Cygnus X-3 system

NASA Technical Reports Server (NTRS)

Stecker, F. W.; Harding, A. K.; Barnard, J. J.

1985-01-01

The effects of an intense beam of ultra-high energy cosmic rays from a compact object in the Cygnus X-3 binary system hitting the companion star, and of the subsequent production of secondary neutrinos, are examined. A maximum allowable beam luminosity of about 10 to the 42nd erg/s is found for a system containing a 1-10 solar mass main sequence target star. The proton beam must heat a relatively small area of the target star to satisfy observational constraints on the resulting stellar wind. With such a model, the neutrino to gamma-ray flux ratio of about 1000 can result from a combination of gamma-ray absorption and a large neutrino to gamma-ray duty cycle ratio. It is found that the high density of the atmosphere resulting from compression by the beam leads to pion cascading and a neutrino spectrum peaking at 1-10 GeV energies.

Final design of thermal diagnostic system in SPIDER ion source

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brombin, M., E-mail: matteo.brombin@igi.cnr.it; Dalla Palma, M.; Pasqualotto, R.

The prototype radio frequency source of the ITER heating neutral beams will be first tested in SPIDER test facility to optimize H{sup −} production, cesium dynamics, and overall plasma characteristics. Several diagnostics will allow to fully characterise the beam in terms of uniformity and divergence and the source, besides supporting a safe and controlled operation. In particular, thermal measurements will be used for beam monitoring and system protection. SPIDER will be instrumented with mineral insulated cable thermocouples, both on the grids, on other components of the beam source, and on the rear side of the beam dump water cooled elements.more » This paper deals with the final design and the technical specification of the thermal sensor diagnostic for SPIDER. In particular the layout of the diagnostic, together with the sensors distribution in the different components, the cables routing and the conditioning and acquisition cubicles are described.« less

Evidence of locally enhanced target heating due to instabilities of counter-streaming fast electron beams

DOE Office of Scientific and Technical Information (OSTI.GOV)

Koester, Petra; Cecchetti, Carlo A.; Booth, Nicola

2015-02-15

The high-current fast electron beams generated in high-intensity laser-solid interactions require the onset of a balancing return current in order to propagate in the target material. Such a system of counter-streaming electron currents is unstable to a variety of instabilities such as the current-filamentation instability and the two-stream instability. An experimental study aimed at investigating the role of instabilities in a system of symmetrical counter-propagating fast electron beams is presented here for the first time. The fast electron beams are generated by double-sided laser-irradiation of a layered target foil at laser intensities above 10{sup 19 }W/cm{sup 2}. High-resolution X-ray spectroscopy ofmore » the emission from the central Ti layer shows that locally enhanced energy deposition is indeed achieved in the case of counter-propagating fast electron beams.« less

Final design of thermal diagnostic system in SPIDER ion source

NASA Astrophysics Data System (ADS)

Brombin, M.; Dalla Palma, M.; Pasqualotto, R.; Pomaro, N.

2016-11-01

The prototype radio frequency source of the ITER heating neutral beams will be first tested in SPIDER test facility to optimize H- production, cesium dynamics, and overall plasma characteristics. Several diagnostics will allow to fully characterise the beam in terms of uniformity and divergence and the source, besides supporting a safe and controlled operation. In particular, thermal measurements will be used for beam monitoring and system protection. SPIDER will be instrumented with mineral insulated cable thermocouples, both on the grids, on other components of the beam source, and on the rear side of the beam dump water cooled elements. This paper deals with the final design and the technical specification of the thermal sensor diagnostic for SPIDER. In particular the layout of the diagnostic, together with the sensors distribution in the different components, the cables routing and the conditioning and acquisition cubicles are described.

New x-ray pink-beam profile monitor system for the SPring-8 beamline front-end

DOE Office of Scientific and Technical Information (OSTI.GOV)

Takahashi, Sunao; Kudo, Togo; Sano, Mutsumi

A new beam profile monitoring system for the small X-ray beam exiting from the SPring-8 front-end was developed and tested at BL13XU. This system is intended as a screen monitor and also as a position monitor even at beam currents of 100 mA by using photoluminescence of a chemical vapor deposition-grown diamond film. To cope with the challenge that the spatial distribution of the photoluminescence in the vertical direction is too flat to detect the beam centroid within a limited narrow aperture, a filter was installed that absorbs the fundamental harmonic concentrated in the beam center, which resulted in “de-flattening”more » of the vertical distribution. For the measurement, the filter crossed the photon beam vertically at high speed to withstand the intense heat flux of the undulator pink-beam. A transient thermal analysis, which can simulate the movement of the irradiation position with time, was conducted to determine the appropriate configuration and the required moving speed of the filter to avoid accidental melting. In a demonstration experiment, the vertically separated beam profile could be successfully observed for a 0.8 × 0.8 mm{sup 2} beam shaped by an XY slit and with a fundamental energy of 18.48 keV. The vertical beam centroid could be detected with a resolution of less than 0.1 mm.« less

Isochoric Heating of Solid-Density Matter with an Ultrafast Proton Beam

DOE Office of Scientific and Technical Information (OSTI.GOV)

Key, M H; Mackinnon, A J; Patel, P K

A new technique is described for the isochoric heating (i.e., heating at constant volume) of matter to high energy-density plasma states (>10{sup 5} J/g) on a picosecond timescale (10{sup -12} sec). An intense, collimated, ultrashort-pulse beam of protons--generated by a high-intensity laser pulse--is used to isochorically heat a solid density material to a temperature of several eV. The duration of heating is shorter than the timescale for significant hydrodynamic expansion to occur, hence the material is heated to a solid density warm dense plasma state. Using spherically-shaped laser targets a focused proton beam is produced and used to heat amore » smaller volume to over 20 eV. The technique described of ultrafast proton heating provides a unique method for creating isochorically heated high-energy density plasma states.« less

Three-dimensional propagation and absorption of high frequency Gaussian beams in magnetoactive plasmas

NASA Astrophysics Data System (ADS)

Nowak, S.; Orefice, A.

1994-05-01

In today's high frequency systems employed for plasma diagnostics, power heating, and current drive the behavior of the wave beams is appreciably affected by the self-diffraction phenomena due to their narrow collimation. In the present article the three-dimensional propagation of Gaussian beams in inhomogeneous and anisotropic media is analyzed, starting from a properly formulated dispersion relation. Particular attention is paid, in the case of electromagnetic electron cyclotron (EC) waves, to the toroidal geometry characterizing tokamak plasmas, to the power density evolution on the advancing wave fronts, and to the absorption features occurring when a beam crosses an EC resonant layer.

Linear beam raster magnet driver based on H-bridge technique

DOEpatents

Sinkine, Nikolai I.; Yan, Chen; Apeldoorn, Cornelis; Dail, Jeffrey Glenn; Wojcik, Randolph Frank; Gunning, William

2006-06-06

An improved raster magnet driver for a linear particle beam is based on an H-bridge technique. Four branches of power HEXFETs form a two-by-two switch. Switching the HEXFETs in a predetermined order and at the right frequency produces a triangular current waveform. An H-bridge controller controls switching sequence and timing. The magnetic field of the coil follows the shape of the waveform and thus steers the beam using a triangular rather than a sinusoidal waveform. The system produces a raster pattern having a highly uniform raster density distribution, eliminates target heating from non-uniform raster density distributions, and produces higher levels of beam current.

Heat load studies of a water-cooled minichannel monochromator for synchrotron x-ray beams

NASA Astrophysics Data System (ADS)

Freund, Andreas K.; Arthur, John R.; Zhang, Lin

1997-12-01

We fabricated a water-cooled silicon monochromator crystal with small channels for the special case of a double-crystal fixed-exit monochromator design where the beam walks across the crystal when the x-ray energy is changed. The two parts of the cooled device were assembled using a new technique based on low melting point solder. The bending of the system produced by this technique could be perfectly compensated by mechanical counter-bending. Heat load tests of the monochromator in a synchrotron beam of 75 W total power, 3 mm high and 15 mm wide, generated by a multipole wiggler at SSRL, showed that the thermal slope error of the crystal is 1 arcsec/40 W power, in full agreement with finite element analysis. The cooling scheme is adequate for bending magnet beamlines at the ESRF and present wiggler beamlines at the SSRL.

High-speed measurement of an air transect's temperature shift heated by laser beam

NASA Astrophysics Data System (ADS)

Li, WenYu; Jiang, ZongFu; Xi, Fengjie; Li, Qiang; Xie, Wenke

2005-02-01

Laser beam heat the air on the optic path, Beam-deflection optical tomography is a non-intrusive method to measure the 2-dimension temperature distribution in the transect. By means of linear Hartmann Sensor at the rate of 27kHz, the optic path was heated by a 2.7μm HF laser, continuous and high time resolution gradients of optic phase were obtained. the result of analysing and calculation showed the temperament shift in the heated beam path was not higher than 50K when the HF laser power was 9W. The experiment showed that it is a practical non-intrusive temperature shift measurement method for a small area aero-optical medium.

Plasma Centrifuge Heat Engine - a Route to Non-thermal p- 11 B Fusion

NASA Astrophysics Data System (ADS)

Barnes, D. C.

2007-06-01

An invention [US Patent and Trademark Office App. Nos. 60/596567 (2005) and 60/766791 (2006)] combines centrifugal and dipole confinement, with recent oscillating plasma theory. The plasma undergoes compression/expansion (C/E), parallel to B by centrifugal force and perpendicular to B by B variation, providing a thermal cycle which recovers most (>95%) of heating as mechanical energy. This gives a "Q-amplifier" for beam-target systems. Centrifugally confined Boron plasma undergoes C/E by slow, cross-B interchange activity. Parallel and perpendicular C/E are matched by the rotation profile which arises naturally. Hot plasma is heated and cold plasma is cooled. Beam-target fusion reactions occur in the hot plasma region and expansion returns most of the heat energy as rotation energy. Rotation energy, in turn, produces waves which drive protons to an energy near the fusion peak cross section. A possible machine, including the arrangement of magnets and HV, is described.

Transport properties of initially neutral gas disturbed by intense electron beam

NASA Astrophysics Data System (ADS)

Angus, Justin; Swanekamp, Steve; Schumer, Joseph; Mosher, Dave; Ottinger, Paul

2013-10-01

The behavior of intense electron beams (those with current densities on the order of hundreds of kA/cm2 and beam rise times on the order of 100 ns) traveling through gaseous mediums depends strongly on the transport properties of the medium. For example, the conductivity of the medium, which is very sensitive to the ionization state and temperature of the gas, has a strong influence on the beam behavior through the plasma return current. Since the beam is responsible for ionizing and heating the gas, self-consistently solving for the gas transport properties and the beam propagation is essential for an accurate description of the system. An advanced gas chemistry model to describe the transport properties of a strongly disturbed gaseous system is presented in this work. A focal point of this work is an accurate description of the medium's conductivity as the gas progresses from its weakly ionized state, where swarm models are valid, to a strongly ionized state where the Spitzer-Harm model applies. NRL Karle Fellowship

Autonomous Laser-Powered Vehicle

NASA Technical Reports Server (NTRS)

Stone, William C. (Inventor); Hogan, Bartholomew P. (Inventor)

2017-01-01

An autonomous laser-powered vehicle designed to autonomously penetrate through ice caps of substantial (e.g., kilometers) thickness by melting a path ahead of the vehicle as it descends. A high powered laser beam is transmitted to the vehicle via an onboard bare fiber spooler. After the beam enters through the dispersion optics, the beam expands into a cavity. A radiation shield limits backscatter radiation from heating the optics. The expanded beam enters the heat exchanger and is reflected by a dispersion mirror. Forward-facing beveled circular grooves absorb the reflected radiant energy preventing the energy from being reflected back towards the optics. Microchannels along the inner circumference of the beam dump heat exchanger maximize heat transfer. Sufficient amount of fiber is wound on the fiber spooler to permit not only a descent but also to permit a sample return mission by inverting the vehicle and melting its way back to the surface.

Uniform heating of materials into the warm dense matter regime with laser-driven quasimonoenergetic ion beams

DOE PAGES

Bang, W.; Albright, B. J.; Bradley, P. A.; ...

2015-12-01

In a recent experiment at the Trident laser facility, a laser-driven beam of quasimonoenergetic aluminum ions was used to heat solid gold and diamond foils isochorically to 5.5 and 1.7 eV, respectively. Here theoretical calculations are presented that suggest the gold and diamond were heated uniformly by these laser-driven ion beams. According to calculations and SESAME equation-of-state tables, laser-driven aluminum ion beams achievable at Trident, with a finite energy spread of ΔE/E~20%, are expected to heat the targets more uniformly than a beam of 140-MeV aluminum ions with zero energy spread. As a result, the robustness of the expected heatingmore » uniformity relative to the changes in the incident ion energy spectra is evaluated, and expected plasma temperatures of various target materials achievable with the current experimental platform are presented.« less

SEE Observations of Ionospheric Heating from HAARP Using Orbital Angular Momentum

NASA Astrophysics Data System (ADS)

Briczinski, S. J.; Bernhardt, P. A.; Siefring, C. L.

2013-12-01

High power HF radio waves exciting the ionosphere provide aeronomers with a unique space-based laboratory capability. The High-Frequency Active Auroral Research Program (HAARP) in Gakona, Alaksa is the world's largest heating facility, providing effective radiated powers in the gigawatt range. Experiments performed at HAARP have allowed researchers to study many non-linear effects of wave-plasma interactions. Stimulated Electromagnetic Emission (SEE) is of interest to the ionospheric community for its diagnostic purposes. Typical SEE experiments at HAARP have focused on characterizing the parametric decay of the electromagnetic pump wave into several different wave modes such as upper and lower hybrid, ion acoustic, ion-Bernstein and electron-Bernstein. These production modes have been extensively studied at HAARP using traditional beam heating patterns and SEE detection. New results are present from HAARP experiments using an excitation mode that attempts to impart orbital angular momentum (OAM) into the heating region. This OAM mode is also referred to as a 'twisted beam.' Previous analysis of twisted beam heating shows that the SEE results obtained are nearly identical to the modes without OAM. Recent twisted beam heating experiments have produced SEE modes not previously characterized. These new modes are presented and discussed. One difference in the twisted beam mode is the heating region produced is in the shape of a ring as opposed to the more traditional 'solid spot' region. The ring heating pattern may be more conducive to the creation of artificial ionization clouds. The results of these runs include artificial ionization creation and evolution as pertaining to the twisted beam pattern.

Improvement of the thermo-mechanical position stability of the beam position monitor in the PLS-II

NASA Astrophysics Data System (ADS)

Ha, Taekyun; Hong, Mansu; Kwon, Hyuckchae; Han, Hongsik; Park, Chongdo

2016-09-01

In the storage ring of the Pohang Light Source-II (PLS-II), we reduced the mechanical displacement of the electron-beam position monitors (e-BPMs) that is caused by heating during e-beam storage. The BPM pickup itself must be kept stable to sub-micrometer precision in order for a stable photon beam to be provided to beamlines because the orbit feedback system is programmed to make the electron beam pass through the center of the BPM. Thermal deformation of the vacuum chambers on which the BPM pickups are mounted is inevitable when the electron beam current is changed by an unintended beam abort. We reduced this deformation by improving the vacuum chamber support and by enhancing the water cooling. We report a thermo-mechanical analysis and displacement measurements for the BPM pickups after improvements.

Collider and Detector Protection at Beam Accidents

NASA Astrophysics Data System (ADS)

Rakhno, I. L.; Mokhov, N. V.; Drozhdin, A. I.

2003-12-01

Dealing with beam loss due to abort kicker prefire is considered for hadron colliders. The prefires occured at Tevatron (Fermilab) during Run I and Run II are analyzed and a protection system implemented is described. The effect of accidental beam loss in the Large Hadron Collider (LHC) at CERN on machine and detector components is studied via realistic Monte Carlo calculations. The simulations show that beam loss at an unsynchronized beam abort would result in severe heating of conventional and superconducting magnets and possible damage to the collider detector elements. A proposed set of collimators would reduce energy deposition effects to acceptable levels. Special attention is paid to reducing peak temperature rise within the septum magnet and minimizing quench region length downstream of the LHC beam abort straight section.

Experiment for transient effects of sudden catastrophic loss of vacuum on a scaled superconducting radio frequency cryomodule

NASA Astrophysics Data System (ADS)

Dalesandro, Andrew A.; Theilacker, Jay; Van Sciver, Steven

2012-06-01

Safe operation of superconducting radio frequency (SRF) cavities require design consideration of a sudden catastrophic loss of vacuum (SCLV) adjacent with liquid helium (LHe) vessels and subsequent dangers. An experiment is discussed to test the longitudinal effects of SCLV along the beam line of a string of scaled SRF cavities. Each scaled cavity includes one segment of beam tube within a LHe vessel containing 2 K saturated LHe, and a riser pipe connecting the LHe vessel to a common gas header. At the beam tube inlet is a fast acting solenoid valve to simulate SCLV and a high/low range orifice plate flow-meter to measure air influx to the cavity. The gas header exit also has an orifice plate flow-meter to measure helium venting the system at the relief pressure of 0.4 MPa. Each cavity is instrumented with Validyne pressure transducers and Cernox thermometers. The purpose of this experiment is to quantify the time required to spoil the beam vacuum and the effects of transient heat and mass transfer on the helium system. Heat transfer data is expected to reveal a longitudinal effect due to the geometry of the experiment. Details of the experimental design criteria and objectives are presented.

Beam loss reduction by magnetic shielding using beam pipes and bellows of soft magnetic materials

NASA Astrophysics Data System (ADS)

Kamiya, J.; Ogiwara, N.; Hotchi, H.; Hayashi, N.; Kinsho, M.

2014-11-01

One of the main sources of beam loss in high power accelerators is unwanted stray magnetic fields from magnets near the beam line, which can distort the beam orbit. The most effective way to shield such magnetic fields is to perfectly surround the beam region without any gaps with a soft magnetic high permeability material. This leads to the manufacture of vacuum chambers (beam pipes and bellows) with soft magnetic materials. A Ni-Fe alloy (permalloy) was selected for the material of the pipe parts and outer bellows parts, while a ferritic stainless steel was selected for the flanges. An austenitic stainless steel, which is non-magnetic material, was used for the inner bellows for vacuum tightness. To achieve good magnetic shielding and vacuum performances, a heat treatment under high vacuum was applied during the manufacturing process of the vacuum chambers. Using this heat treatment, the ratio of the integrated magnetic flux density along the beam orbit between the inside and outside of the beam pipe and bellows became small enough to suppress beam orbit distortion. The outgassing rate of the materials with this heat treatment was reduced by one order magnitude compared to that without heat treatment. By installing the beam pipes and bellows of soft magnetic materials as part of the Japan Proton Accelerator Research Complex 3 GeV rapid cycling synchrotron beam line, the closed orbit distortion (COD) was reduced by more than 80%. In addition, a 95.5% beam survival ratio was achieved by this COD improvement.

Device and method for electron beam heating of a high density plasma

DOEpatents

Thode, L.E.

A device and method for relativistic electron beam heating of a high density plasma in a small localized region are described. A relativistic electron beam generator produces a high voltage electron beam which propagates along a vacuum drift tube and is modulated to initiate electron bunching within the beam. The beam is then directed through a low density gas chamber which provides isolation between the vacuum modulator and the relativistic electron beam target. The relativistic beam is then applied to a high density target plasma which typically comprises DT, DD, hydrogen boron or similar thermonuclear gas at a density of 10/sup 17/ to 10/sup 20/.

Diffraction spectral filter for use in extreme-UV lithography condenser

DOEpatents

Sweatt, William C.; Tichenor, Daniel A.; Bernardez, Luis J.

2002-01-01

A condenser system for generating a beam of radiation includes a source of radiation light that generates a continuous spectrum of radiation light; a condenser comprising one or more first optical elements for collecting radiation from the source of radiation light and for generating a beam of radiation; and a diffractive spectral filter for separating first radiation light having a particular wavelength from the continuous spectrum of radiation light. Cooling devices can be employed to remove heat generated. The condenser system can be used with a ringfield camera in projection lithography.

Optimization of the SHX Fusion Powered Transatmospheric Propulsion Concept

NASA Technical Reports Server (NTRS)

Adams, Robert B.; Landrum, D. Brian

2001-01-01

Existing propulsion technology has not achieved cost effective payload delivery rates to low earth orbit. A fusion based propulsion system, denoted as the Simultaneous Heating and eXpansion (SHX) engine, has been proposed in earlier papers. The SHX couples energy generated by a fusion reactor to the engine flowpath by use of coherent beam emitters. A quasi-one-dimensional flow model was used to quantify the effects of area expansion and energy input on propulsive efficiency for several beam models. Entropy calculations were included to evaluate the lost work in the system.

Beam-return current systems in solar flares

NASA Technical Reports Server (NTRS)

Spicer, D. S.; Sudan, R. N.

1984-01-01

It is demonstrated that the common assumption made in solar flare beam transport theory that the beam-accompanied return current is purely electrostatically driven is incorrect, and that the return current is both electrostatically and inductively driven, in accordance with Lenz's law, with the inductive effects dominating for times greater than a few plasma periods. In addition, it is shown that a beam can only exist in a solar plasma for a finite time which is much smaller than the inductive return current dissipation time. The importance of accounting for the role of the acceleration mechanism in forming the beam is discussed. In addition, the role of return current driven anomalous resistivity and its subsequent anomalous Joule heating during the flare process is elucidated.

Weld pool development during GTA and laser beam welding of Type 304 stainless steel; Part I - theoretical analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zacharia, T.; David, S.A.; Vitek, J.M.

1989-12-01

A computational and experimental study was carried out to quantitatively understand the influence of the heat flow and the fluid flow in the transient development of the weld pool during gas tungsten arc (GTA) and laser beam welding of Type 304 stainless steel. Stationary gas tungsten arc and laser beam welds were made on two heats of Type 304 austenitic stainless steels containing 90 ppm sulfur and 240 ppm sulfur. A transient heat transfer model was utilized to simulate the heat flow and fluid flow in the weld pool. In this paper, the results of the heat flow and fluidmore » flow analysis are presented.« less

Construction of a system for single-cell transgene induction in Caenorhabditis elegans using a pulsed infrared laser

PubMed Central

Churgin, Matthew A.; He, Liping; Murray, John I.; Fang-Yen, Christopher

2014-01-01

The spatial and temporal control of transgene expression is an important tool in C. elegans biology. We previously described a method for evoking gene expression in arbitrary cells by using a focused pulsed infrared laser to induce a heat shock response (Churgin et al 2013). Here we describe detailed methods for building and testing a system for performing single-cell heat shock. Steps include setting up the laser and associated components, coupling the laser beam to a microscope, and testing heat shock protocols. All steps can be carried out using readily available off-the-shelf components. PMID:24835576

[The development of a distribution system for medical lasers and its clinical application].

PubMed

Okae, S; Ishiguchi, T; Ishigaki, T; Sakuma, S

1991-02-25

We developed a new laser beam generator system which can deliver laser beam to multiple terminals in distant clinical therapy rooms. The system possesses the distribution equipment by which Nd-YAG laser power is distributed to 8 output terminals under the computer control. Distributed laser beam is delivered to each distant terminal with clinical informations through the optical fiber. In the fundamental studies, possibility of distant transportation of laser beam (30 m) only with 10% loss of energy and without dangerous heating at the connection parts was shown. There seems to be no disadvantage associated with distribution laser beam. In the clinical study, the system was applied to five patients with the symptoms including hemosputum, esophageal stenosis, hemorrhage, lip ulcer and pain. Clinical usefulness of the system was proved. The advantages of the system are as follows: 1. Benefit of cost reduction due to multiple use of single laser source. 2. No necessity of transport of the equipment. 3. No requirement of a wide space to install the equipment in the distant room. 4. Efficient management and maintenance of the system by centralization. Further improvements, e.g., simultaneous use at multiple terminals and elongation of transportation up to 340 m, make the system more useful for clinical application.

Aerodynamic levitator for in situ x-ray structure measurements on high temperature and molten nuclear fuel materials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Weber, J. K. R.; Alderman, O. L. G.; Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439

2016-07-15

An aerodynamic levitator with carbon dioxide laser beam heating was integrated with a hermetically sealed controlled atmosphere chamber and sample handling mechanism. The system enabled containment of radioactive samples and control of the process atmosphere chemistry. The chamber was typically operated at a pressure of approximately 0.9 bars to ensure containment of the materials being processed. Samples 2.5-3 mm in diameter were levitated in flowing gas to achieve containerless conditions. Levitated samples were heated to temperatures of up to 3500 °C with a partially focused carbon dioxide laser beam. Sample temperature was measured using an optical pyrometer. The sample environment wasmore » integrated with a high energy (100 keV) x-ray synchrotron beamline to enable in situ structure measurements to be made on levitated samples as they were heated, melted, and supercooled. The system was controlled from outside the x-ray beamline hutch by using a LabVIEW program. Measurements have been made on hot solid and molten uranium dioxide and binary uranium dioxide-zirconium dioxide compositions.« less

Aerodynamic levitator for in situ x-ray structure measurements on high temperature and molten nuclear fuel materials

DOE PAGES

Weber, J. K. R.; Tamalonis, A.; Benmore, C. J.; ...

2016-07-01

We integrated an aerodynamic levitator with carbon dioxide laser beam heating with a hermetically sealed controlled atmosphere chamber and sample handling mechanism. The system enabled containment of radioactive samples and control of the process atmosphere chemistry. Furthermore, the chamber was typically operated at a pressure of approximately 0.9 bars to ensure containment of the materials being processed. Samples 2.5-3 mm in diameter were levitated in flowing gas to achieve containerless conditions. Levitated samples were heated to temperatures of up to 3500 °C with a partially focused carbon dioxide laser beam. Sample temperature was measured using an optical pyrometer. The samplemore » environment was integrated with a high energy (100 keV) x-ray synchrotron beamline to enable in situ structure measurements to be made on levitated samples as they were heated, melted, and supercooled. Our system was controlled from outside the x-ray beamline hutch by using a LabVIEW program. Measurements have been made on hot solid and molten uranium dioxide and binary uranium dioxide-zirconium dioxide compositions.« less

Device and method for relativistic electron beam heating of a high-density plasma to drive fast liners

DOEpatents

Thode, Lester E.

1981-01-01

A device and method for relativistic electron beam heating of a high-density plasma in a small localized region. A relativistic electron beam generator or accelerator produces a high-voltage electron beam which propagates along a vacuum drift tube and is modulated to initiate electron bunching within the beam. The beam is then directed through a low-density gas chamber which provides isolation between the vacuum modulator and the relativistic electron beam target. The relativistic beam is then applied to a high-density target plasma which typically comprises DT, DD, hydrogen boron or similar thermonuclear gas at a density of 10.sup.17 to 10.sup.20 electrons per cubic centimeter. The target gas is ionized prior to application of the electron beam by means of a laser or other preionization source to form a plasma. Utilizing a relativistic electron beam with an individual particle energy exceeding 3 MeV, classical scattering by relativistic electrons passing through isolation foils is negligible. As a result, relativistic streaming instabilities are initiated within the high-density target plasma causing the relativistic electron beam to efficiently deposit its energy and momentum into a small localized region of the high-density plasma target. Fast liners disposed in the high-density target plasma are explosively or ablatively driven to implosion by a heated annular plasma surrounding the fast liner which is generated by an annular relativistic electron beam. An azimuthal magnetic field produced by axial current flow in the annular plasma, causes the energy in the heated annular plasma to converge on the fast liner.

Radiation-Thermal Sintering of Zirconia Powder Compacts Under Conditions of Bilateral Heating Using Beams of Low-Energy Electrons

NASA Astrophysics Data System (ADS)

Ghyngazov, S. A.; Frangulyan, T. S.; Chernyavskii, A. V.; Goreev, A. K.; Naiden, E. P.

2015-06-01

Comparative experiments on sintering zirconia ceramics are performed using colliding beams of low-energy electrons and under conditions of thermal heating. The density and microhardness of ceramic materials manufactured via different processes are determined. The use of a regime of bilateral heating by high-intensity,low-energy electron beams is shown to intensify the sintering process and yield material specimens with improved characteristics compared to those formed by thermal sintering.

Production of fibers by a floating zone fiber drawing technique

NASA Technical Reports Server (NTRS)

Haggerty, J. S.

1972-01-01

A CO2 laser heated, floating zone fiber growth process was developed. The resulting Al2O3 fibers exhibited the high room temperature strengths for large diameter fibers as well as high specific creep rupture strengths observed at 1093 C and 1316 C (2000 F and 2400 F). Single crystal fibers of TiC and Y2O3 were also grown. An optical system was developed to focus four CO2 laser beams onto the surface of a feed rod permitting the formation of highly controllable molten zones. The optical system permitted energy densities and angle of incidence of the beams to be adjusted over wide ranges. This optical system was incorporated into a controlled atmosphere, fiber growth furnace. The two principal advantages of a CO2 laser heat source are that ambient atmospheres may be freely selected to optimize fiber properties and the laser has no inherent temperature limit, so extremely high melting point materials can be melted. Both advantages were demonstrated.

Beam shaping to provide round and square-shaped beams in optical systems of high-power lasers

NASA Astrophysics Data System (ADS)

Laskin, Alexander; Laskin, Vadim

2016-05-01

Optical systems of modern high-power lasers require control of irradiance distribution: round or square-shaped flat-top or super-Gaussian irradiance profiles are optimum for amplification in MOPA lasers and for thermal load management while pumping of crystals of solid-state ultra-short pulse lasers to control heat and minimize its impact on the laser power and beam quality while maximizing overall laser efficiency, variable profiles are also important in irradiating of photocathode of Free Electron lasers (FEL). It is suggested to solve the task of irradiance re-distribution using field mapping refractive beam shapers like piShaper. The operational principle of these devices presumes transformation of laser beam intensity from Gaussian to flat-top one with high flatness of output wavefront, saving of beam consistency, providing collimated output beam of low divergence, high transmittance, extended depth of field, negligible residual wave aberration, and achromatic design provides capability to work with ultra-short pulse lasers having broad spectrum. Using the same piShaper device it is possible to realize beams with flat-top, inverse Gauss or super Gauss irradiance distribution by simple variation of input beam diameter, and the beam shape can be round or square with soft edges. This paper will describe some design basics of refractive beam shapers of the field mapping type and optical layouts of their applying in optical systems of high-power lasers. Examples of real implementations and experimental results will be presented as well.

Cryosorption Pumps for a Neutral Beam Injector Test Facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dremel, M.; Mack, A.; Day, C.

2006-04-27

We present the experiences of the manufacturing and the operating of a system of two identical cryosorption pumps used in a neutral beam injector test facility for fusion reactors. Calculated and measured heat loads of the cryogenic liquid helium and liquid nitrogen circuits of the cryosorption pumps are discussed. The design calculations concerning the thermo-hydraulics of the helium circuit are compared with experiences from the operation of the cryosorption pumps. Both cryopumps are integrated in a test facility of a neutral beam injector that will be used to heat the plasma of a nuclear fusion reactor with a beam ofmore » deuterium or hydrogen molecules. The huge gas throughput into the vessel of the test facility results in challenging needs on the cryopumping system.The developed cryosorption pumps are foreseen to pump a hydrogen throughput of 20 - 30 mbar{center_dot}l/s. To establish a mean pressure of several 10-5 mbar in the test vessel a pumping speed of about 350 m3/s per pump is needed. The pressure conditions must be maintained over several hours pumping without regeneration of the cryopanels, which necessitates a very high pumping capacity. A possibility to fulfill these requirements is the use of charcoal coated cryopanels to pump the gasloads by adsorption. For the cooling of the cryopanels, liquid helium at saturation pressure is used and therefore a two-phase forced flow in the cryopump system must be controlled.« less

Beyond ITER: neutral beams for a demonstration fusion reactor (DEMO) (invited).

PubMed

McAdams, R

2014-02-01

In the development of magnetically confined fusion as an economically sustainable power source, International Tokamak Experimental Reactor (ITER) is currently under construction. Beyond ITER is the demonstration fusion reactor (DEMO) programme in which the physics and engineering aspects of a future fusion power plant will be demonstrated. DEMO will produce net electrical power. The DEMO programme will be outlined and the role of neutral beams for heating and current drive will be described. In particular, the importance of the efficiency of neutral beam systems in terms of injected neutral beam power compared to wallplug power will be discussed. Options for improving this efficiency including advanced neutralisers and energy recovery are discussed.

Regimes of enhanced electromagnetic emission in beam-plasma interactions

NASA Astrophysics Data System (ADS)

Timofeev, I. V.; Annenkov, V. V.; Arzhannikov, A. V.

2015-11-01

The ways to improve the efficiency of electromagnetic waves generation in laboratory experiments with high-current relativistic electron beams injected into a magnetized plasma are discussed. It is known that such a beam can lose, in a plasma, a significant part of its energy by exciting a high level of turbulence and heating plasma electrons. Beam-excited plasma oscillations may simultaneously participate in nonlinear processes resulting in a fundamental and second harmonic emissions. It is obvious, however, that in the developed plasma turbulence the role of these emissions in the total energy balance is always negligible. In this paper, we investigate whether electromagnetic radiation generated in the beam-plasma system can be sufficiently enhanced by the direct linear conversion of resonant beam-driven modes into electromagnetic ones on preformed regular inhomogeneities of plasma density. Due to the high power of relativistic electron beams, the mechanism discussed may become the basis for the generator of powerful sub-terahertz radiation.

Space-Based Solar Power Conversion and Delivery Systems Study. Volume 3: Microwave Power Transmission Studies

NASA Technical Reports Server (NTRS)

1977-01-01

The Microwave Fower Beam Ionosphere effects and critical interfaces between th Microwave Power Transmission System (MPTS) and the Satellite were studied as part of the NASA/MSFC continuing research on the feasibility of power transmission from geosynchronous orbit. Theoretical predications of ionospheric modifications produced by the direct interaction of the MPTS on the earth's upper atmosphere are used to determine their impact on the performance of the Microwave Power Beam and Pilot Beam System as well as on other RF systems effected by the ionosphere. A technology program to quantitatively define these interactions is developed. Critical interface areas between the MPTS and the satellite which could have a major impact on cost and performance of the power system are idenfified and analyzed. The areas selected include: use of either a 20 kV versus 40 kV Amplitron, thermal blockage effects of Amplitron heat radiation by the satellite structure, effect of dielectric carry-through structure on power beam, and effect of material sublimation on performance of the Amplitron in Geosynchronous Orbit.

High Power Hydrogen Injector with Beam Focusing for Plasma Heating

DOE Office of Scientific and Technical Information (OSTI.GOV)

Deichuli, P.P.; Ivanov, A.A.; Korepanov, S.A.

2005-01-15

High power neutral beam injector has been developed with the atom energy of 25 keV, a current of 60 A, and several milliseconds pulse duration. Six of these injectors will be used for upgrade of the atomic injection system at central cell of a Gas Dynamic Trap (GDT) device and 2 injectors are planned for SHIP experiment.The injector ion source is based on an arc discharge plasma box. The plasma emitter is produced by a 1 kA arc discharge in hydrogen. A multipole magnetic field produced with permanent magnets at the periphery of the plasma box is used to increasemore » its efficiency and improve homogeneity of the plasma emitter. The ion beam is extracted by a 4-electrodes ion optical system (IOS). Initial beam diameter is 200 mm. The grids of the IOS have a spherical curvature for geometrical focusing of the beam. The optimal IOS geometry and grid potentials were found with the numerical simulation to provide precise beam formation. The measured angular divergence of the beam is 0.02 rad, which corresponds to the 2.5 cm Gaussian radius of the beam profile measured at focal point.« less

Low energy, high power hydrogen neutral beam for plasma heating

DOE Office of Scientific and Technical Information (OSTI.GOV)

Deichuli, P.; Davydenko, V.; Ivanov, A., E-mail: ivanov@inp.nsk.su

A high power, relatively low energy neutral beam injector was developed to upgrade of the neutral beam system of the gas dynamic trap device and C2-U experiment. The ion source of the injector produces a proton beam with the particle energy of 15 keV, current of up to 175 A, and pulse duration of a few milliseconds. The plasma emitter of the ion source is produced by superimposing highly ionized plasma jets from an array of four arc-discharge plasma generators. A multipole magnetic field produced with permanent magnets at the periphery of the plasma box is used to increase themore » efficiency and improve the uniformity of the plasma emitter. Multi-slit grids with 48% transparency are fabricated from bronze plates, which are spherically shaped to provide geometrical beam focusing. The focal length of the Ion Optical System (IOS) is 3.5 m and the initial beam diameter is 34 cm. The IOS geometry and grid potentials were optimized numerically to ensure accurate beam formation. The measured angular divergences of the beam are ±0.01 rad parallel to the slits and ±0.03 rad in the transverse direction.« less

Long pulse acceleration of MeV class high power density negative H{sup −} ion beam for ITER

DOE Office of Scientific and Technical Information (OSTI.GOV)

Umeda, N., E-mail: umeda.naotaka@jaea.go.jp; Kojima, A.; Kashiwagi, M.

2015-04-08

R and D of high power density negative ion beam acceleration has been carried out at MeV test facility in JAEA to realize ITER neutral beam accelerator. The main target is H{sup −} ion beam acceleration up to 1 MeV with 200 A/m{sup 2} for 60 s whose pulse length is the present facility limit. For long pulse acceleration at high power density, new extraction grid (EXG) has been developed with high cooling capability, which electron suppression magnet is placed under cooling channel similar to ITER. In addition, aperture size of electron suppression grid (ESG) is enlarged from 14 mmmore » to 16 mm to reduce direct interception on the ESG and emission of secondary electron which leads to high heat load on the upstream acceleration grid. By enlarging ESG aperture, beam current increased 10 % at high current beam and total acceleration grid heat load reduced from 13 % to 10 % of input power at long pulse beam. In addition, heat load by back stream positive ion into the EXG is measured for the first time and is estimated as 0.3 % of beam power, while heat load by back stream ion into the source chamber is estimated as 3.5 ~ 4.0 % of beam power. Beam acceleration up to 60 s which is the facility limit, has achieved at 683 keV, 100 A/m{sup 2} of negative ion beam, whose energy density increases two orders of magnitude since 2011.« less

Thermal waves or beam heating in the 1980, November 5 flare

NASA Technical Reports Server (NTRS)

Smith, Dean F.

1986-01-01

Observations of the temporal evolution of loop BC in soft X rays in the November 5, 1980 flare are reviewed. Calculations are performed to model this evolution. The most consistent interpretation involving a minimum account of energy is the following. Thermal heating near B gives rise to a conduction front which moves out along the loop uninhibited for about 27 s. Beam heating near C gives rise to a second conduction front which moves in the opposite direction and prevents any energy reaching C by thermal conduction from B. Thus both thermal waves and beam heating are required to explain the observed evolution.

Thermoelectronic laser energy conversion for power transmission in space

NASA Technical Reports Server (NTRS)

Britt, E. J.; Yuen, C.

1977-01-01

Long distance transmission of power in space by means of laser beams is an attractive concept because of the very narrow beam divergence. Such a system requires efficient means to both generate the laser beam and to convert the light energy in the beam into useful electric output at the receiver. A plasma-type device known as a Thermo-Electronic Laser Energy Converter (TELEC) has been studied as a method of converting a 10.6 micron CO2 laser beam into electric power. In the TELEC process, electromagnetic radiation is absorbed directly in the plasma electrons producing a high electron temperature. The energetic electrons diffuse out of the plasma striking two electrodes with different areas. Since more electrons are collected by the larger electrode there is a net transport of current, and an EMF is generated in the external circuit. The smaller electrode functions as an electron emitter to provide continuity of the current. Waste heat is rejected from the large electrode. A design for a TELEC system with an input 1 MW laser beam was developed as part of the study. The calculated performance of the system showed an overall efficiency of about 42%.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Xiaoyong, E-mail: zhangxy@buaa.edu.cn, E-mail: yanxiaojun@buaa.edu.cn; Yan, Xiaojun, E-mail: zhangxy@buaa.edu.cn, E-mail: yanxiaojun@buaa.edu.cn; Collaborative Innovation Center of Advanced Aero-Engine, Beijing 100191

This note presents a component-level frequency tunable isolator for vibration-sensitive chips. The isolator employed 8 U-shaped shape memory alloy (SMA) beams to support an isolation island (used for mounting chips). Due to the temperature-induced Young’s modulus variation of SMA, the system stiffness of the isolator can be controlled through heating the SMA beams. In such a way, the natural frequency of the isolator can be tuned. A prototype was fabricated to evaluate the concept. The test results show that the natural frequency of the isolator can be tuned in the range of 64 Hz–97 Hz by applying different heating strategies.more » Moreover, resonant vibration can be suppressed significantly (the transmissibility decreases about 65% near the resonant frequency) using a real-time tuning method.« less

Operation of the CAPRICE electron cyclotron resonance ion source applying frequency tuning and double frequency heating.

PubMed

Maimone, F; Tinschert, K; Celona, L; Lang, R; Mäder, J; Rossbach, J; Spädtke, P

2012-02-01

The properties of the electromagnetic waves heating the electrons of the ECR ion sources (ECRIS) plasma affect the features of the extracted ion beams such as the emittance, the shape, and the current, in particular for higher charge states. The electron heating methods such as the frequency tuning effect and the double frequency heating are widely used for enhancing the performances of ECRIS or even for the routine operation during the beam production. In order to better investigate these effects the CAPRICE ECRIS has been operated using these techniques. The ion beam properties for highly charged ions have been measured with beam diagnostic tools. The reason of the observed variations of this performance can be related to the different electromagnetic field patterns, which are changing inside the plasma chamber when the frequency is varying.

Electron-beam lithography for micro and nano-optical applications

NASA Technical Reports Server (NTRS)

Wilson, Daniel W.; Muller, Richard E.; Echternach, Pierre M.

2005-01-01

Direct-write electron-beam lithography has proven to be a powerful technique for fabricating a variety of micro- and nano-optical devices. Binary E-beam lithography is the workhorse technique for fabricating optical devices that require complicated precision nano-scale features. We describe a bi-layer resist system and virtual-mark height measurement for improving the reliability of fabricating binary patterns. Analog E-beam lithography is a newer technique that has found significant application in the fabrication of diffractive optical elements. We describe our techniques for fabricating analog surface-relief profiles in E-beam resist, including some discussion regarding overcoming the problems of resist heating and charging. We also describe a multiple-field-size exposure scheme for suppression of field-stitch induced ghost diffraction orders produced by blazed diffraction gratings on non-flat substrates.

Pressure and temperature fluctuation simulation of J-PARC cryogenic hydrogen system

NASA Astrophysics Data System (ADS)

Tatsumoto, H.; Ohtsu, K.; Aso, T.; Kawakami, Y.

2015-12-01

The J-PARC cryogenic hydrogen system provides supercritical cryogenic hydrogen to the moderators at a pressure of 1.5 MPa and temperature of 18 K and removes 3.8 kW of nuclear heat from the 1 MW proton beam operation. We prepared a heater for thermal compensation and an accumulator, with a bellows structure for volume control, to mitigate the pressure fluctuation caused by switching the proton beam on and off. In this study, a 1-D simulation code named DiSC-SH2 was developed to understand the propagation of pressure and temperature propagations through the hydrogen loop due to on and off switching of the proton beam. We confirmed that the simulated dynamic behaviors in the hydrogen loop for 300-kW and 500-kW proton beam operations agree well with the experimental data under the same conditions.

Simulations of the Mg II K and Ca II 8542 Lines From an Alfvén Wave-Heated Flare Chromosphere

NASA Technical Reports Server (NTRS)

Kerr, Graham S.; Fletcher, Lyndsay; Russell, Alexander J. B.; Allred, Joel C.

2016-01-01

We use radiation hydrodynamic simulations to examine two models of solar flare chromospheric heating: Alfven wave dissipation and electron beam collisional losses. Both mechanisms are capable of strong chromospheric heating, and we show that the distinctive atmospheric evolution in the mid-to-upper chromosphere results in Mg II k-line emission that should be observably different between wave-heated and beam-heated simulations. We also present Ca II 8542 A profiles that are formed slightly deeper in the chromosphere. The Mg II k-line profiles from our wave-heated simulation are quite different from those from a beam-heated model and are more consistent with Interface Region Imaging Spectrograph observations. The predicted differences between the Ca II 8542 A in the two models are small. We conclude that careful observational and theoretical study of lines formed in the mid-to-upper chromosphere holds genuine promise for distinguishing between competing models for chromospheric heating inflares.

Evaluation of ITER MSE Viewing Optics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Allen, S; Lerner, S; Morris, K

2007-03-26

The Motional Stark Effect (MSE) diagnostic on ITER determines the local plasma current density by measuring the polarization angle of light resulting from the interaction of a high energy neutral heating beam and the tokamak plasma. This light signal has to be transmitted from the edge and core of the plasma to a polarization analyzer located in the port plug. The optical system should either preserve the polarization information, or it should be possible to reliably calibrate any changes induced by the optics. This LLNL Work for Others project for the US ITER Project Office (USIPO) is focused on themore » design of the viewing optics for both the edge and core MSE systems. Several design constraints were considered, including: image quality, lack of polarization aberrations, ease of construction and cost of mirrors, neutron shielding, and geometric layout in the equatorial port plugs. The edge MSE optics are located in ITER equatorial port 3 and view Heating Beam 5, and the core system is located in equatorial port 1 viewing heating beam 4. The current work is an extension of previous preliminary design work completed by the ITER central team (ITER resources were not available to complete a detailed optimization of this system, and then the MSE was assigned to the US). The optimization of the optical systems at this level was done with the ZEMAX optical ray tracing code. The final LLNL designs decreased the ''blur'' in the optical system by nearly an order of magnitude, and the polarization blur was reduced by a factor of 3. The mirror sizes were reduced with an estimated cost savings of a factor of 3. The throughput of the system was greater than or equal to the previous ITER design. It was found that optical ray tracing was necessary to accurately measure the throughput. Metal mirrors, while they can introduce polarization aberrations, were used close to the plasma because of the anticipated high heat, particle, and neutron loads. These mirrors formed an intermediate image that then was relayed out of the port plug with more ideal (dielectric) mirrors. Engineering models of the optics, port plug, and neutral beam geometry were also created, using the CATIA ITER models. Two video conference calls with the USIPO provided valuable design guidelines, such as the minimum distance of the first optic from the plasma. A second focus of the project was the calibration of the system. Several different techniques are proposed, both before and during plasma operation. Fixed and rotatable polarizers would be used to characterize the system in the no-plasma case. Obtaining the full modulation spectrum from the polarization analyzer allows measurement of polarization effects and also MHD plasma phenomena. Light from neutral beam interaction with deuterium gas (no plasma) has been found useful to determine the wavelength of each spatial channel. The status of the optical design for the edge (upper) and core (lower) systems is included in the following figure. Several issues should be addressed by a follow-on study, including whether the optical labyrinth has sufficient neutron shielding and a detailed polarization characterization of actual mirrors.« less

Assembly and commissioning of a new SRF cryomodule for the ATLAS intensity upgrade

NASA Astrophysics Data System (ADS)

Conway, Z. A.; Barcikowski, A.; Cherry, G. L.; Fischer, R. L.; Fuerst, J. D.; Jansma, W. G.; Gerbick, S. M.; Kedzie, M. J.; Kelly, M. P.; Kim, S. H.; MacDonald, S. W. T.; Murphy, R. C.; Ostroumov, P. N.; Reid, T. C.; Shepard, K. W.

2014-01-01

The Argonne National Laboratory Physics Division is in the final stages of a major upgrade to the Argonne Tandem Linear Accelerator System national user facility, referred to as the intensity upgrade. The intensity upgrade project will substantially increase beam currents for experimenters working with the existing ATLAS stable and in-flight rare isotope beams and for the neutron-rich beams from the Californium Rare Isotope Breeder Upgrade. This project includes the replacement of three existing cryomodules, containing 18 superconducting accelerator cavities and 9 superconducting solenoids, with a single cryomodule with seven SC 72.75 MHz accelerator cavities optimized for ion velocities of 7.7% the speed of light and 4 SC solenoids all operating at 4.5 K. This presentation will report: how we minimized the heat load into the 4 K and 80 K coolant streams feeding the cryomodule, a comparison of the calculated and measured static heat loads at 80 K and the mechanical design of the vacuum vessel.

Unsteady spot heating of a drop in a microgravity environment

NASA Technical Reports Server (NTRS)

Sadhal, Satwindar Singh; Trinh, Eugene H.; Wagner, Paul

1992-01-01

The unsteady localized spot heating of a liquid drop under zero-g conditions is examined theoretically. This pertains to space experiments to measure thermal properties of materials and the purpose here is to predict the thermal behavior of such systems. Spot heating can be achieved by a laser beam focused on a small region of the drop surface. The present theoretical model deals with situations of weak Marangoni flows, whereby the thermal transport is conduction dominated. The heat flow in the drop is treated as unsteady while the surrounding gaseous region is considered to be quasisteady. The ensuing thermally driven flow is analyzed in the Stokes regime.

Proton core-beam system in the expanding solar wind: Hybrid simulations

NASA Astrophysics Data System (ADS)

Hellinger, Petr; Trávníček, Pavel M.

2011-11-01

Results of a two-dimensional hybrid expanding box simulation of a proton beam-core system in the solar wind are presented. The expansion with a strictly radial magnetic field leads to a decrease of the ratio between the proton perpendicular and parallel temperatures as well as to an increase of the ratio between the beam-core differential velocity and the local Alfvén velocity creating a free energy for many different instabilities. The system is indeed most of the time marginally stable with respect to the parallel magnetosonic, oblique Alfvén, proton cyclotron and parallel fire hose instabilities which determine the system evolution counteracting some effects of the expansion and interacting with each other. Nonlinear evolution of these instabilities leads to large modifications of the proton velocity distribution function. The beam and core protons are slowed with respect to each other and heated, and at later stages of the evolution the two populations are not clearly distinguishable. On the macroscopic level the instabilities cause large departures from the double adiabatic prediction leading to an efficient isotropization of effective proton temperatures in agreement with Helios observations.

Boring and Sealing Rock with Directed Energy Millimeter-Waves

NASA Astrophysics Data System (ADS)

Woskov, P.; Einstein, H. H.; Oglesby, K.

2015-12-01

Millimeter-wave directed energy is being investigated to penetrate into deep crystalline basement rock formations to lower well costs and to melt rocks, metals, and other additives to seal wells for applications that include nuclear waste storage and geothermal energy. Laboratory tests have established that intense millimeter-wave (MMW) beams > 1 kW/cm2 can melt and/ or vaporize hard crystalline rocks. In principle this will make it possible to create open boreholes and a method to seal them with a glass/ceramic liner and plug formed from the original rock or with other materials. A 10 kW, 28 GHz commercial (CPI) gyrotron system with a launched beam diameter of about 32 mm was used to heat basalt, granite, limestone, and sandstone specimens to temperatures over 2500 °C to create melts and holes. A calibrated 137 GHz radiometer view, collinear with the heating beam, monitored real time peak rock temperature. A water load surrounding the rock test specimen primarily monitored unabsorbed power at 28 GHz. Power balance analysis of the laboratory observations shows that the temperature rise is limited by radiative heat loss, which would be expected to be trapped in a borehole. The analysis also indicates that the emissivity (absorption efficiency) in the radiated infrared range is lower than the emissivity at 28 GHz, giving the MMW frequency range an important advantage for rock melting. Strength tests on one granite type indicated that heating the rock initially weakens it, but with exposure to higher temperatures the resolidified black glassy product regains strength. Basalt was the easiest to melt and penetrate, if a melt leak path was provided, because of its low viscosity. Full beam holes up to about 50 mm diameter (diffraction increased beam size) were achieved through 30 mm thick basalt and granite specimens. Laboratory experiments to form a seal in an existing hole have also been carried out by melting rock and a simulated steel casing.

Beam Heating of Samples: Modeling and Verification. Part 2

NASA Technical Reports Server (NTRS)

Kazmierczak, Michael; Gopalakrishnan, Pradeep; Kumar, Raghav; Banerjee Rupak; Snell, Edward; Bellamy, Henry; Rosenbaum, Gerd; vanderWoerd, Mark

2006-01-01

Energy absorbed from the X-ray beam by the sample requires cooling by forced convection (i.e. cryostream) to minimize temperature increase and the damage caused to the sample by the X-ray heating. In this presentation we will first review the current theoretical models and recent studies in the literature, which predict the sample temperature rise for a given set of beam parameters. It should be noted that a common weakness of these previous studies is that none of them provide actual experimental confirmation. This situation is now remedied in our investigation where the problem of x-ray sample heating is taken up once more. We have theoretically investigated, and at the same time, in addition to the numerical computations, performed experiments to validate the predictions. We have modeled, analyzed and experimentally tested the temperature rise of a 1 mm diameter glass sphere (sample surrogate) exposed to an intense synchrotron X-ray beam, while it is being cooled in a uniform flow of nitrogen gas. The heat transfer, including external convection and internal heat conduction was theoretically modeled using CFD to predict the temperature variation in the sphere during cooling and while it was subjected to an undulator (ID sector 19) X-ray beam at the APS. The surface temperature of the sphere during the X-ray beam heating was measured using the infrared camera measurement technique described in a previous talk. The temperatures from the numerical predictions and experimental measurements are compared and discussed. Additional results are reported for the two different sphere sizes and for two different supporting pin orientations.

System and method for laser-based, non-evaporative repair of damage sites in the surfaces of fused silica optics

DOEpatents

Adams, John J.; Bolourchi, Masoud; Bude, Jeffrey D.; Guss, Gabriel M.; Jarboe, Jeffery A.; Matthews, Manyalibo J.; Nostrand, Michael C; Wegner, Paul J.

2016-09-06

A method for repairing a damage site on a surface of an optical material is disclosed. The method may involve focusing an Infrared (IR) laser beam having a predetermined wavelength, with a predetermined beam power, to a predetermined full width ("F/W") 1/e.sup.2 diameter spot on the damage site. The focused IR laser beam is maintained on the damage site for a predetermined exposure period corresponding to a predetermined acceptable level of downstream intensification. The focused IR laser beam heats the damage site to a predetermined peak temperature, which melts and reflows material at the damage site of the optical material to create a mitigated site.

Telescope-based cavity for negative ion beam neutralization in future fusion reactors.

PubMed

Fiorucci, Donatella; Hreibi, Ali; Chaibi, Walid

2018-03-01

In future fusion reactors, heating system efficiency is of the utmost importance. Photo-neutralization substantially increases the neutral beam injector (NBI) efficiency with respect to the foreseen system in the International Thermonuclear Experimental Reactor (ITER) based on a gaseous target. In this paper, we propose a telescope-based configuration to be used in the NBI photo-neutralizer cavity of the demonstration power plant (DEMO) project. This configuration greatly reduces the total length of the cavity, which likely solves overcrowding issues in a fusion reactor environment. Brought to a tabletop experiment, this cavity configuration is tested: a 4 mm beam width is obtained within a ≃1.5  m length cavity. The equivalent cavity g factor is measured to be 0.038(3), thus confirming the cavity stability.

Conceptual design of the EU DEMO EC-system: main developments and R&D achievements

NASA Astrophysics Data System (ADS)

Granucci, G.; Aiello, G.; Alberti, S.; Avramidis, K. A.; Braunmüller, F.; Bruschi, A.; Chelis, J.; Franck, J.; Figini, L.; Gantenbein, G.; Garavaglia, S.; Grossetti, G.; Illy, S.; Ioannidis, Z.; Jelonnek, J.; Kalaria, P.; Latsas, G.; Moro, A.; Pagonakis, I. Gr.; Peponis, D.; Poli, E.; Rispoli, N.; Rzesnicki, T.; Scherer, T.; Strauss, D.; Thumm, M.; Tigelis, I.; Tsironis, C.; Wu, C.; Franke, T.; Tran, M. Q.

2017-11-01

For the development of a DEMOnstration Fusion Power Plant the design of auxiliary heating systems is a key activity in order to achieve controlled burning plasma. The present heating mix considers electron cyclotron resonance heating (ECRH), neutral beam injection (NBI) and ion cyclotron resonance heating (ICRH) with a target power to the plasma of about 50 MW for each system. The main tasks assigned to the EC system are plasma breakdown and assisted start-up, heating to L-H transition and plasma current ramp up to burn, MHD stability control and assistance in plasma current ramp down. The consequent requirements are used for the conceptual design of the EC system, from the RF source to the launcher, with an extensive R&D program focused on relevant technologies to be developed. Gyrotron: the R&D and Advanced Developments on EC RF sources are targeting for gyrotrons operating at 240 GHz, considered as optimum EC Current Drive frequency in case of higher magnetic field than for the 2015 EU DEMO1 baseline. Multi-purpose (multi-frequency) and frequency step-tunable gyrotrons are under investigation to increase the flexibility of the system. As main targets an output power of significantly above 1 MW (target: 2 MW) and a total efficiency higher than 60% are set. The principle feasibility at limits of a 236 GHz, conventional-cavity and, alternatively, of a 238 GHz coaxial-cavity gyrotron are under investigation together with the development of a synthetic diamond Brewster-angle window technology. Advanced developments are on-going in the field of multi-stage depressed collector technologies. Transmission line (TL): different TL options are under investigation and a preliminary study of an evacuated quasi-optical multiple-beam TL, considered for a hybrid solution, is presented and discussed in terms of layout, dimensions and theoretical losses. Launcher: remote steering antennas have been considered as a possible launcher solution especially under the constraints to avoid movable mirrors close to the plasma. With dedicated beam tracing calculations, the deposition locations coverage and the wave absorption efficiency have been investigated, considering a selection of frequencies, injection angles and launching points. An option for the EC system structure is proposed in clusters, in order to allow the necessary redundancy and flexibility to guarantee the required EC power in the different phases of the plasma pulse. Number and composition of the clusters are analysed to have high availability and therefore maximum reliability with a minimum number of components.

SU-E-T-408: Determination of KQ,Q0-Factors From Water and Graphite Calorimetry in a 60 MeV Proton Beam

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rossomme, S; Renaud, J; Sarfehnia, A

2014-06-01

Purpose: To reduce the uncertainty of the beam quality correction factor k Q,Q0, for scattered proton beams (SPB). This factor is used in dosimetry protocols, to determine absorbed dose-to-water with ionization chambers. For the Roos plane parallel chambers (RPPICs), the IAEA TRS-398 protocol estimates k Q,Q0-factor to be 1.004(for a beam quality Rres=2 g.cm{sup 2}), with an uncertainty of 2.1%. Methods: A graphite calorimeter (GCal), a water calorimeter (WCal) and RPPICs were exposed, in a single experiment, to a 60 MeV non-modulated SPB. RPPICs were calibrated in terms of absorbed dose-to-water in a 20 MeV electron beam. The calibration coefficientmore » is traceable to NPL's absorbed dose standards. Chamber measurements were corrected for environmental conditions, recombination and polarity. The WCal corrections include heat loss, heat defect and vessel perturbation. The GCal corrections include heat loss and absorbed dose conversion. Except for heat loss correction and its uncertainty in the WCal system, all major corrections were included in the analysis. Other minor corrections, such as beam profile non-uniformity, are still to be evaluated. Experimental k Q,Q0-factors were derived by comparing the results obtained with both calorimeters and ionometry. Results: The absorbed dose-to-water from both calorimeters was found to be within 1.3% with an uncertainty of 1.2%. k Q,Q0-factor for a RPPIC was found to be 0.998 and 1.011, with a standard uncertainty of 1.4% and 0.9% when the dose is based on the GCal and the WCal, respectively. Conclusion: Results suggest the possibility to determine k Q,Q0-values for PPICs in SPB with a lower uncertainty than specified in the TRS-398 thereby helping to reduce uncertainty on absorbed dose-to-water. The agreement between calorimeters confirms the possibility to use GCal or WCal as primary standard in SPB. Because of the dose conversion, the use of GCal may lead to slightly higher uncertainty, but is, at present, considerably easier to operate.« less

Impurity segregation behavior in polycrystalline silicon ingot grown with variation of electron-beam power

NASA Astrophysics Data System (ADS)

Lee, Jun-Kyu; Lee, Jin-Seok; Jang, Bo-Yun; Kim, Joon-Soo; Ahn, Young-Soo; Cho, Churl-Hee

2014-08-01

Electron beam melting (EBM) systems have been used to improve the purity of metallurgical grade silicon feedstock for photovoltaic application. Our advanced EBM system is able to effectively remove volatile impurities using a heat source with high energy from an electron gun and to continuously allow impurities to segregate at the top of an ingot solidified in a directional solidification (DS) zone in a vacuum chamber. Heat in the silicon melt should move toward the ingot bottom for the desired DS. However, heat flux though the ingot is changed as the ingot becomes longer due to low thermal conductivity of silicon. This causes a non-uniform microstructure of the ingot, finally leading to impurity segregation at its middle. In this research, EB power irradiated on the silicon melt was controlled during the ingot growth in order to suppress the change of heat flux. EB power was reduced from 12 to 6.6 kW during the growth period of 45 min with a drop rate of 0.125 kW/min. Also, the silicon ingot was grown under a constant EB power of 12 kW to estimate the effect of the drop rate of EB power. When the EB power was reduced, the grains with columnar shape were much larger at the middle of the ingot compared to the case of constant EB power. Also, the present research reports a possible reason for the improvement of ingot purity by considering heat flux behaviors.

In situ baking method for degassing of a kicker magnet in accelerator beam line

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kamiya, Junichiro, E-mail: kamiya.junichiro@jaea.go.jp; Ogiwara, Norio; Yanagibashi, Toru

In this study, the authors propose a new in situ degassing method by which only kicker magnets in the accelerator beam line are baked out without raising the temperature of the vacuum chamber to prevent unwanted thermal expansion of the chamber. By simply installing the heater and thermal radiation shield plates between the kicker magnet and the chamber wall, most of the heat flux from the heater directs toward the kicker magnet. The result of the verification test showed that each part of the kicker magnet was heated to above the target temperature with a small rise in the vacuummore » chamber temperature. A graphite heater was selected in this application to bake-out the kicker magnet in the beam line to ensure reliability and easy maintainability of the heater. The vacuum characteristics of graphite were suitable for heater operation in the beam line. A preliminary heat-up test conducted in the accelerator beam line also showed that each part of the kicker magnet was successfully heated and that thermal expansion of the chamber was negligibly small.« less

Color change of tourmaline by heat treatment and electron beam irradiation: UV-Visible, EPR, and Mid-IR spectroscopic analyses

NASA Astrophysics Data System (ADS)

Maneewong, Apichate; Seong, Baek Seok; Shin, Eun Joo; Kim, Jeong Seog; Kajornrith, Varavuth

2016-01-01

The color of pink tourmaline gemstone changed to colorless when heating at temperature of 600 °C in air. This colorless tourmaline recovered its pink color when irradiated with an electron beam (e-beam) of 800 kGy. The origin of the color change was investigated in three types of tourmaline gemstones, two pink are from Afghanistan and one green are from Nigeria, by using Ultraviolet-visible spectroscopy (UV-Vis), Fourier-transform infrared spectroscopy (FTIR), Electron paramagnetic resonance (EPR), and Energy Dispersive X-ray Fluorescence (EDXRF). The UV-Vis absorption spectrum of the pink tourmaline with higher Mn concentration (T2, 0.24 wt%) showed characteristic absorption peaks originating from the Mn3+ color center: two absorption bands centered at wavelength of 396 and 520 nm, respectively. Both absorption bands disappeared when heated in air at 600 °C and then reappeared when irradiated with an e-beam at 800 kGy. EPR T2 spectra showed that the color change was related to the valence change of Mn3+ to Mn2+ and vice versa. The pink tourmaline of lower MnO content (T1, 0.08 wt%) also became colorless when heated, but the color was not recovered when the gemstone underwent e-beam irradiation. Instead, a yellow color was obtained. UV-Vis and FTIR spectra indicated that this yellow color originated from a decomposition of the hydroxyl group (-OH) into O- and Ho by the e-beam irradiation. Green tourmaline did not show any color change with either heat treatment or e-beam irradiation.

Propagation of a laser beam in a time-varying waveguide. [plasma heating for controlled fusion

NASA Technical Reports Server (NTRS)

Chapman, J. M.; Kevorkian, J.

1978-01-01

The propagation of an axisymmetric laser beam in a plasma column having a radially parabolic electron density distribution is reported. For the case of an axially uniform waveguide it is found that the basic characteristics of alternating focusing and defocusing beams are maintained. However, the intensity distribution is changed at the foci and outer-beam regions. The features of paraxial beam propagation are discussed with reference to axially varying waveguides. Laser plasma coupling is considered noting the case where laser heating produces a density distribution radially parabolic near the axis and the energy absorbed over the focal length of the plasma is small. It is found that: (1) beam-propagation stability is governed by the relative magnitude of the density fluctuations existing in the axial variation of the waveguides due to laser heating, and (2) for beam propagation in a time-varying waveguide, the global instability of the propagation is a function of the initial fluctuation growth rate as compared to the initial time rate of change in the radial curvature of the waveguide.

Theoretical explanation of the polarization-converting system achieved by beam shaping and combination technique and its performance under high power conditions

NASA Astrophysics Data System (ADS)

Wang, Peng; Li, Xiao; Shang, YaPing; Xu, XiaoJun

2015-10-01

The fiber laser has very obvious advantages and broad applications in remote welding, 3D cutting and national defense compared with the traditional solid laser. But influenced by heat effect of gain medium, nonlinear effect, stress birefringence effect and other negative factors, it's very difficult to get high power linearly polarized laser just using a single laser. For these limitations a polarization-converting system is designed using beam shaping and combination technique which is able to transform naturally polarized laser to linearly polarized laser at real time to resolve difficulties of generating high-power linearly polarized laser from fiber lasers in this paper. The principle of the Gaussian beam changing into the hollow beam passing through two axicons and the combination of the Gaussian beam and the hollow beam is discussed. In the experimental verification the energy conversion efficiency reached 93.1% with a remarkable enhancement of the extinction ratio from 3% to 98% benefited from the high conversion efficiency of axicons and the system worked fine under high power conditions. The system also kept excellent far field divergence. The experiment phenomenon also agreed with the simulation quite well. The experiment proves that this polarization-converting system will not affect laser structure which controls easily and needs no feedback and controlling system with stable and reliable properties at the same time. It can absolutely be applied to the polarization-conversion of high power laser.

Surface relief structures for multiple beam LO generation

NASA Technical Reports Server (NTRS)

Veldkamp, W. B.

1980-01-01

Linear and binary holograms for use in heterodyne detection with 10.6 micron imaging arrays are described. The devices match the amplitude and phase of the local oscillator to the received signal and thus maximize the system signal to noise ratio and resolution and minimize heat generation on the focal plane. In both the linear and binary approaches, the holographic surface-relief pattern is coded to generate a set of local oscillator beams when the relief pattern is illuminated by a single planewave. Each beam of this set has the same amplitude shape distribution as, and is collinear with, each single element wavefront illuminating array.

New Approaches to Final Cooling

DOE Office of Scientific and Technical Information (OSTI.GOV)

Neuffer, David

2014-11-10

A high-energy muon collider scenario require a “final cooling” system that reduces transverse emittances by a factor of ~10 while allowing longitudinal emittance increase. The baseline approach has low-energy transverse cooling within high-field solenoids, with strong longitudinal heating. This approach and its recent simulation are discussed. Alternative approaches which more explicitly include emittance exchange are also presented. Round-to-flat beam transform, transverse slicing, and longitudinal bunch coalescence are possible components of the alternative approach. A more explicit understanding of solenoidal cooling beam dynamics is introduced.

Knudsen torque on heated micro beams

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Qi; Liang, Tengfei; Ye, Wenjing

Thermally induced mechanical loading has been shown to have significant effects on micro/nano objects immersed in a gas with a non-uniform temperature field. While the majority of existing studies and related applications focus on forces, we investigate the torque, and thus the rotational motion, produced by such a mechanism. Using the asymptotic analysis in the near continuum regime, the Knudsen torque acting on an asymmetrically located uniformly heated microbeam in a cold enclosure is investigated. The existence of a non-zero net torque is demonstrated. In addition, it has been found that by manipulating the system configuration, the rotational direction ofmore » the torque can be changed. Two types of rotational motion of the microbeam have been identified: the pendulum motion of a rectangular beam, and the unidirectional rotation of a cylindrical beam. A rotational frequency of 4 rpm can be achieved for the cylindrical beam with a diameter of 3μm at Kn = 0.005. Illustrated by the simulations using the direct simulation of Monte Carlo, the Knudsen torque can be much increased in the transition regime, demonstrating the potential of Knudsen torque serving as a rotation engine for micro/nano objects.« less

The use of holographic interferometry for measurements of temperature in a rectangular heat pipe. M.S. Thesis

NASA Technical Reports Server (NTRS)

Marn, Jure

1989-01-01

Holographic interferometry is a nonintrusive method and as such possesses considerable advantages such as not disturbing the velocity and temperature field by creating obstacles which would alter the flow field. These optical methods have disadvantages as well. Holography, as one of the interferometry methods, retains the accuracy of older methods, and at the same time eliminates the system error of participating components. The holographic interferometry consists of comparing the objective beam with the reference beam and observing the difference in lengths of optical paths, which can be observed during the propagation of the light through a medium with locally varying refractive index. Thus, change in refractive index can be observed as a family of nonintersecting surfaces in space (wave fronts). The object of the investigation was a rectangular heat pipe. The goal was to measure temperatures in the heat pipe, which yields data for computer code or model assessment. The results were obtained by calculating the temperatures by means of finite fringes.

Chevron beam dump for ITER edge Thomson scattering system.

PubMed

Yatsuka, E; Hatae, T; Vayakis, G; Bassan, M; Itami, K

2013-10-01

This paper contains the design of the beam dump for the ITER edge Thomson scattering system and mainly concerns its lifetime under the harsh thermal and electromagnetic loads as well as tight space allocation. The lifetime was estimated from the multi-pulse laser-induced damage threshold. In order to extend its lifetime, the structure of the beam dump was optimized. A number of bent sheets aligned parallel in the beam dump form a shape called a chevron which enables it to avoid the concentration of the incident laser pulse energy. The chevron beam dump is expected to withstand thermal loads due to nuclear heating, radiation from the plasma, and numerous incident laser pulses throughout the entire ITER project with a reasonable margin for the peak factor of the beam profile. Structural analysis was also carried out in case of electromagnetic loads during a disruption. Moreover, detailed issues for more accurate assessments of the beam dump's lifetime are clarified. Variation of the bi-directional reflection distribution function (BRDF) due to erosion by or contamination of neutral particles derived from the plasma is one of the most critical issues that needs to be resolved. In this paper, the BRDF was assumed, and the total amount of stray light and the absorbed laser energy profile on the beam dump were evaluated.

Ion acceleration and heating by kinetic Alfvén waves associated with magnetic reconnection

NASA Astrophysics Data System (ADS)

Liang, Ji; Lin, Yu; Johnson, Jay R.; Wang, Zheng-Xiong; Wang, Xueyi

2017-10-01

Our previous study on the generation and signatures of kinetic Alfvén waves (KAWs) associated with magnetic reconnection in a current sheet revealed that KAWs are a common feature during reconnection [Liang et al. J. Geophys. Res.: Space Phys. 121, 6526 (2016)]. In this paper, ion acceleration and heating by the KAWs generated during magnetic reconnection are investigated with a three-dimensional (3-D) hybrid model. It is found that in the outflow region, a fraction of inflow ions are accelerated by the KAWs generated in the leading bulge region of reconnection, and their parallel velocities gradually increase up to slightly super-Alfvénic. As a result of wave-particle interactions, an accelerated ion beam forms in the direction of the anti-parallel magnetic field, in addition to the core ion population, leading to the development of non-Maxwellian velocity distributions, which include a trapped population with parallel velocities consistent with the wave speed. The ions are heated in both parallel and perpendicular directions. In the parallel direction, the heating results from nonlinear Landau resonance of trapped ions. In the perpendicular direction, however, evidence of stochastic heating by the KAWs is found during the acceleration stage, with an increase of magnetic moment μ. The coherence in the perpendicular ion temperature T⊥ and the perpendicular electric and magnetic fields of KAWs also provides evidence for perpendicular heating by KAWs. The parallel and perpendicular heating of the accelerated beam occur simultaneously, leading to the development of temperature anisotropy with T⊥>T∥ . The heating rate agrees with the damping rate of the KAWs, and the heating is dominated by the accelerated ion beam. In the later stage, with the increase of the fraction of the accelerated ions, interaction between the accelerated beam and the core population also contributes to the ion heating, ultimately leading to overlap of the beams and an overall anisotropy with T∥>T⊥ .

Ion acceleration and heating by kinetic Alfvén waves associated with magnetic reconnection

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liang, Ji; Lin, Yu; Johnson, Jay R.

In a previous study on the generation and signatures of kinetic Alfv en waves (KAWs) associated with magnetic reconnection in a current sheet revealed that KAWs are a common feature during reconnection [Liang et al. J. Geophys. Res.: Space Phys. 121, 6526 (2016)]. In this paper, ion acceleration and heating by the KAWs generated during magnetic reconnection are investigated with a three-dimensional (3-D) hybrid model. It is found that in the outflow region, a fraction of inflow ions are accelerated by the KAWs generated in the leading bulge region of reconnection, and their parallel velocities gradually increase up to slightly super-Alfv enic. As a result of waveparticle interactions, an accelerated ion beam forms in the direction of the anti-parallel magnetic field, in addition to the core ion population, leading to the development of non-Maxwellian velocity distributions, which include a trapped population with parallel velocities consistent with the wave speed. We then heat ions in both parallel and perpendicular directions. In the parallel direction, the heating results from nonlinear Landau resonance of trapped ions. In the perpendicular direction, however, evidence of stochastic heating by the KAWs is found during the acceleration stage, with an increase of magnetic moment μ. The coherence in the T more » $$\\perp$$ ion temperature and the perpendicular electric and magnetic fields of KAWs also provides evidence for perpendicular heating by KAWs. The parallel and perpendicular heating of the accelerated beam occur simultaneously, leading to the development of temperature anisotropy with the perpendicular temperature T $$\\perp$$>T $$\\parallel$$ temperature. The heating rate agrees with the damping rate of the KAWs, and the heating is dominated by the accelerated ion beam. In the later stage, with the increase of the fraction of the accelerated ions, interaction between the accelerated beam and the core population also contributes to the ion heating, ultimately leading to overlap of the beams and an overall anisotropy with T $$\\perp$$>T $$\\parallel$$.« less

Ion acceleration and heating by kinetic Alfvén waves associated with magnetic reconnection

DOE PAGES

Liang, Ji; Lin, Yu; Johnson, Jay R.; ...

2017-09-19

In a previous study on the generation and signatures of kinetic Alfv en waves (KAWs) associated with magnetic reconnection in a current sheet revealed that KAWs are a common feature during reconnection [Liang et al. J. Geophys. Res.: Space Phys. 121, 6526 (2016)]. In this paper, ion acceleration and heating by the KAWs generated during magnetic reconnection are investigated with a three-dimensional (3-D) hybrid model. It is found that in the outflow region, a fraction of inflow ions are accelerated by the KAWs generated in the leading bulge region of reconnection, and their parallel velocities gradually increase up to slightly super-Alfv enic. As a result of waveparticle interactions, an accelerated ion beam forms in the direction of the anti-parallel magnetic field, in addition to the core ion population, leading to the development of non-Maxwellian velocity distributions, which include a trapped population with parallel velocities consistent with the wave speed. We then heat ions in both parallel and perpendicular directions. In the parallel direction, the heating results from nonlinear Landau resonance of trapped ions. In the perpendicular direction, however, evidence of stochastic heating by the KAWs is found during the acceleration stage, with an increase of magnetic moment μ. The coherence in the T more » $$\\perp$$ ion temperature and the perpendicular electric and magnetic fields of KAWs also provides evidence for perpendicular heating by KAWs. The parallel and perpendicular heating of the accelerated beam occur simultaneously, leading to the development of temperature anisotropy with the perpendicular temperature T $$\\perp$$>T $$\\parallel$$ temperature. The heating rate agrees with the damping rate of the KAWs, and the heating is dominated by the accelerated ion beam. In the later stage, with the increase of the fraction of the accelerated ions, interaction between the accelerated beam and the core population also contributes to the ion heating, ultimately leading to overlap of the beams and an overall anisotropy with T $$\\perp$$>T $$\\parallel$$.« less

Solar project description for Gill Harrop Builders single-family detached residence, Big Flats, New York

NASA Astrophysics Data System (ADS)

1982-04-01

A house with approximately 1360 square feet of conditioned space heated by a direct gain system with manually operated insulated curtains is discussed. Solar heating is augmented by electric resistance heating, and a wood burning stove may be installed. Sunlight is admitted through both south facing windows and through clerestory collector panels and is absorbed and stored as heat in a concrete floor and wall. Heat is then distributed by natural convection and radiation. Temperature regulation is assisted by Earth beams. Three modes of operation are described: collector-to-storage, storage-to-space heating, and passive space cooling, which is accomplished by shading, movable insulation, and ventilation. The instrumentation for the National Solar Data Network is described. The solar energy portion of the construction costs is estimated.

A near infra-red video system as a protective diagnostic for electron cyclotron resonance heating operation in the Wendelstein 7-X stellarator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Preynas, M.; Laqua, H. P.; Marsen, S.

The Wendelstein 7-X stellarator is a large nuclear fusion device based at Max-Planck-Institut für Plasmaphysik in Greifswald in Germany. The main plasma heating system for steady state operation in W7-X is electron cyclotron resonance heating (ECRH). During operation, part of plama facing components will be directly heated by the non-absorbed power of 1 MW rf beams of ECRH. In order to avoid damages of such components made of graphite tiles during the first operational phase, a near infra-red video system has been developed as a protective diagnostic for safe and secure ECRH operation. Both the mechanical design housing the cameramore » and the optical system are very flexible and respect the requirements of steady state operation. The full system including data acquisition and control system has been successfully tested in the vacuum vessel, including on-line visualization and data storage of the four cameras equipping the ECRH equatorial launchers of W7-X.« less

Neutral Beam Driven Neoclassical Transport in NSTX

NASA Astrophysics Data System (ADS)

Houlberg, W. A.; Shaing, K. C.; Callen, J. D.

2002-11-01

We re-examine the particle and heat flows driven by neutral beam injection in tokamak plasmas. These appear as inward pinches for co-injection and outward for counter injection. We derive the parallel friction and heat friction forces exerted on the thermal species by the energetic beam ions by extending the early analysis of Callen, et al. [1], which are then used as external forces in the moments formulation of neoclassical transport in NCLASS [2]. NCLASS is based on the multiple species treatment of Hirshman and Sigmar [3]. Of particular interest is the ion energy flux driven by the heat friction term. It scales as the beam energy, while the particle and electron heat terms scale as the thermal plasma temperature. In NSTX the high beam energy to plasma temperature ratio may lead to a net negative ion heat flux with strong co-injection. Limtations to the theory, such as the large fast ion orbit size relative to the radius of the flux surface, are discussed. Comparisons are made with earlier works by Hinton and Kim [4] and Stacey [5], who evaluated only the beam-thermal friction. [1] J.D. Callen, et al, 5th IAEA, Tokyo (1974), Vol 1, 645 [2] W.A. Houlberg, K.C. Shaing, S.P. Hirshman, M.C. Zarnstorff, Phys. Plasmas 4 (1997) 3230 [3] S.P. Hirshman, D.J. Sigmar, Nucl. Fusion 21 (1981) 1079 [4] F.L. Hinton, Y.-B. Kim, Phys. Fluids B 5 (1993) 3012 [5] W.M. Stacey, Phys. Fluids B 5 (1993) 4505

Regimes of enhanced electromagnetic emission in beam-plasma interactions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Timofeev, I. V.; Annenkov, V. V.; Arzhannikov, A. V.

2015-11-15

The ways to improve the efficiency of electromagnetic waves generation in laboratory experiments with high-current relativistic electron beams injected into a magnetized plasma are discussed. It is known that such a beam can lose, in a plasma, a significant part of its energy by exciting a high level of turbulence and heating plasma electrons. Beam-excited plasma oscillations may simultaneously participate in nonlinear processes resulting in a fundamental and second harmonic emissions. It is obvious, however, that in the developed plasma turbulence the role of these emissions in the total energy balance is always negligible. In this paper, we investigate whethermore » electromagnetic radiation generated in the beam-plasma system can be sufficiently enhanced by the direct linear conversion of resonant beam-driven modes into electromagnetic ones on preformed regular inhomogeneities of plasma density. Due to the high power of relativistic electron beams, the mechanism discussed may become the basis for the generator of powerful sub-terahertz radiation.« less

Simplified Analysis of Airspike Heat Flux Into Lightcraft Thermal Management System

NASA Astrophysics Data System (ADS)

Head, Dean R.; Seo, Junghwa; Cassenti, Brice N.; Myrabo, Leik N.

2005-04-01

An approximate method is presented for estimating the airspike heat flux into a 9-meter diameter lightcraft, integrated over its flight to low Earth orbit. The super-pressure lightcraft's exotic twin-hull, sandwich structure is assumed to be fabricated from SiC/SiC thin-film ceramic matrix composites of semiconductor grade purity, giving superior structural properties while being transparent to 35-GHz microwave radiation. The vehicle's MHD slipstream accelerator engine is energized by an annular microwave power beam — converted on-board into DC electric power by two concentric, water-cooled microwave rectenna arrays. The vehicle's airspike is created by a central 3-m diameter laser beam that sustains a laser-supported detonation wave at a distance of 10-m ahead of the craft; the LSD wave propagates up the beam with a velocity that matches the lightcraft's flight speed. The simplified analysis, which is based on aerodynamic heating during re-entry, shows that helium flowing at a velocity of 10 m/s through the lightcraft's double-hull is sufficient to keep the outer, 0.13-mm thick SiC skin safely under its maximum service temperature. The interior helium pressurant that maintains the structural integrity of this exotic pressure-airship, increases in temperature by only 25 K during the flight to LEO.

Production of plasmas by long-wavelength lasers

DOEpatents

Dawson, J.M.

1973-10-01

A long-wavelength laser system for heating low-density plasma to high temperatures is described. In one embodiment, means are provided for repeatedly receiving and transmitting long-wavelength laser light in successive stages to form a laser-light beam path that repeatedly intersects with the equilibrium axis of a magnetically confined toroidal plasma column for interacting the laser light with the plasma for providing controlled thermonuclear fusion. Embodiments for heating specific linear plasmas are also provided. (Official Gazette)

Utilization of Additive Manufacturing for Aerospace Heat Exchangers

DTIC Science & Technology

2016-02-29

is made up of flat plates that are layered on top of each other creating air passages in between the plates where the hot liquid and cold liquid flow...electron beam- based) for two-dimensional scanning of the heat source on the powder layer , stages that decrease the build plate and increase the powder...build plate and result in uneven coating of subsequent powder layers or complete failure of the system to recoat. The perturbations in recoater

Atomic magnetometer

DOEpatents

Schwindt, Peter [Albuquerque, NM; Johnson, Cort N [Albuquerque, NM

2012-07-03

An atomic magnetometer is disclosed which uses a pump light beam at a D1 or D2 transition of an alkali metal vapor to magnetically polarize the vapor in a heated cell, and a probe light beam at a different D2 or D1 transition to sense the magnetic field via a polarization rotation of the probe light beam. The pump and probe light beams are both directed along substantially the same optical path through an optical waveplate and through the heated cell to an optical filter which blocks the pump light beam while transmitting the probe light beam to one or more photodetectors which generate electrical signals to sense the magnetic field. The optical waveplate functions as a quarter waveplate to circularly polarize the pump light beam, and as a half waveplate to maintain the probe light beam linearly polarized.

Evaluation of Heat Dissipation in the BPM Buttons

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pinayev,I.; Blednyhk, A.

2009-05-04

Growth of circulating current in the storage rings drastically increases heating of the beam position monitor (BPM) buttons due to the induced trapped modes is drastically increasing. Excessive heating can lead to the errors in the measuring of beam position or even catastrophic failures of the pick-up assembly. In this paper we present calculations of heat generated in the button for different geometries and materials. The obtained results are used for the optimization of the NSLS-II BPM buttons design.

Acoustic Levitator With Furnace And Laser Heating

NASA Technical Reports Server (NTRS)

Barmatz, Martin B.; Stoneburner, James D.

1991-01-01

Acoustic-levitation apparatus incorporates electrical-resistance furnace for uniform heating up to temperature of about 1,000 degrees C. Additional local heating by pair of laser beams raise temperature of sample to more than 1,500 degrees C. High temperature single-mode acoustic levitator generates cylindrical-mode accoustic resonance levitating sample. Levitation chamber enclosed in electrical-resistance furnace. Infrared beams from Nd:YAG laser provide additional local heating of sample. Designed for use in containerless processing of materials in microgravity or in normal Earth gravity.

Impurity transport during neutral beam injection in the ISX-B tokamak

DOE Office of Scientific and Technical Information (OSTI.GOV)

Isler, R. C.; Crume, E. C.; Arnurius, D. E.

1980-10-01

In ohmically heated ISX-B discharges, both the intrinsic iron impurity ions and small amounts of argon introduced as a test gas accumulate at the center of the plasma. But during certain beam-heated discharges, it appears that this accumulation does not take place. These results may reflect the conclusion of Stacey and Sigmar that momentum transferred from the beams to the plasma can inhibit inward impurity transport.

Development of Rapid Pipe Moulding Process for Carbon Fiber Reinforced Thermoplastics by Direct Resistance Heating

NASA Astrophysics Data System (ADS)

Tanaka, Kazuto; Harada, Ryuki; Uemura, Toshiki; Katayama, Tsutao; Kuwahara, Hideyuki

To deal with environmental issues, the gasoline mileage of passenger cars can be improved by reduction of the car weight. The use of car components made of Carbon Fiber Reinforced Plastics (CFRP) is increasing because of its superior mechanical properties and relatively low density. Many vehicle structural parts are pipe-shaped, such as suspension arms, torsion beams, door guard bars and impact beams. A reduction of the car weight is expected by using CFRP for these parts. Especially, when considering the recyclability and ease of production, Carbon Fiber Reinforced Thermoplastics are a prime candidate. On the other hand, the moulding process of CFRTP pipes for mass production has not been well established yet. For this pipe moulding process an induction heating method has been investigated already, however, this method requires a complicated coil system. To reduce the production cost, another system without such complicated equipment is to be developed. In this study, the pipe moulding process of CFRTP using direct resistance heating was developed. This heating method heats up the mould by Joule heating using skin effect of high-frequency current. The direct resistance heating method is desirable from a cost perspective, because this method can heat the mould directly without using any coils. Formerly developed Non-woven Stitched Multi-axial Cloth (NSMC) was used as semi-product material. NSMC is very suitable for the lamination process due to the fact that non-crimp stitched carbon fiber of [0°/+45°/90°/-45°] and polyamide 6 non-woven fabric are stitched to one sheet, resulting in a short production cycle time. The use of the pipe moulding process with the direct resistance heating method in combination with the NSMC, has resulted in the successful moulding of a CFRTP pipe of 300 mm in length, 40 mm in diameter and 2 mm in thickness.

Satellite Power System (SPS) microwave subsystem impacts and benefits

NASA Technical Reports Server (NTRS)

Dickinson, R. M.

1977-01-01

The impacts and benefits to society of the microwave subsystem resulting from the developing, construction and operating of a space solar power to earth, electric power delivery system are presented and discussed. The primary benefit (usable energy) is conveyed mainly in the fundamental frequency portion of the RF radiation beam that is intercepted and converted to electric power output. The small fraction of the microwave and other electromagnetic energy that does not end up in the electric utility grid, yields most of the subsystem impacts. The impacts range from harmonics and noise radiated by the transmitting antenna, through potential interference with ionospheric communications and navigation caused by the power beam heating the ionosphere, to the potential large land area requirements for the rectennas and low level microwave radiation around the rectennas. Additional benefits range from a very low level of waste heat liberated and lack of atmospheric emissions including noise while operating to having no residual ionizing radiation from the rectenna when it is deactivated.

Microelectromechanical (MEM) thermal actuator

DOEpatents

Garcia, Ernest J [Albuquerque, NM; Fulcher, Clay W. G. [Sandia Park, NM

2012-07-31

Microelectromechanical (MEM) buckling beam thermal actuators are disclosed wherein the buckling direction of a beam is constrained to a desired direction of actuation, which can be in-plane or out-of-plane with respect to a support substrate. The actuators comprise as-fabricated, linear beams of uniform cross section supported above the substrate by supports which rigidly attach a beam to the substrate. The beams can be heated by methods including the passage of an electrical current through them. The buckling direction of an initially straight beam upon heating and expansion is controlled by incorporating one or more directional constraints attached to the substrate and proximal to the mid-point of the beam. In the event that the beam initially buckles in an undesired direction, deformation of the beam induced by contact with a directional constraint generates an opposing force to re-direct the buckling beam into the desired direction. The displacement and force generated by the movement of the buckling beam can be harnessed to perform useful work, such as closing contacts in an electrical switch.

Negative ion beam characterisation in BATMAN by mini-STRIKE: Improved design and new measurements

NASA Astrophysics Data System (ADS)

Serianni, G.; Bonomo, F.; Brombin, M.; Cervaro, V.; Chitarin, G.; Cristofaro, S.; Delogu, R.; De Muri, M.; Fasolo, D.; Fonnesu, N.; Franchin, L.; Franzen, P.; Ghiraldelli, R.; Molon, F.; Muraro, A.; Pasqualotto, R.; Ruf, B.; Schiesko, L.; Tollin, M.; Veltri, P.

2015-04-01

The ITER project requires additional heating provided by two injectors of neutral beams resulting from the neutralisation of accelerated negative ions. To study and optimise negative ion production, the SPIDER test facility (particle energy 100keV; beam current 50A) is under construction in Padova, with the aim of testing beam characteristics and to verify the source proper operation. The SPIDER beam will be characterised by the instrumented calorimeter STRIKE, whose main components are one-directional carbon fibre carbon composite tiles. Some prototype tiles have been employed in 2012 as a small-scale version (mini-STRIKE) of the entire system to investigate the features of the beam from BATMAN at IPP-Garching. As the BATMAN beamlets are superposed at the measurement position, about 1m from the grounded grid, an actively cooled copper mask is located in front of the tiles; holes in the mask create an artificial beamlet structure. Recently the mini-STRIKE has been updated, taking into account the results obtained in the first campaign. In particular the spatial resolution of the system has been improved by increasing the number of the copper mask holes. Moreover a custom measurement system has been realized for the thermocouple signals and employed in BATMAN in view of its use in SPIDER. The present contribution gives a description of the new design of the system as well as of the thermocouple measurements system and its field test. A new series of measurements has been carried out in BATMAN. The BATMAN beam characterisation in different experimental conditions is presented.

Negative ion beam characterisation in BATMAN by mini-STRIKE: Improved design and new measurements

DOE Office of Scientific and Technical Information (OSTI.GOV)

Serianni, G., E-mail: gianluigi.serianni@igi.cnr.it; Brombin, M.; Cervaro, V.

The ITER project requires additional heating provided by two injectors of neutral beams resulting from the neutralisation of accelerated negative ions. To study and optimise negative ion production, the SPIDER test facility (particle energy 100keV; beam current 50A) is under construction in Padova, with the aim of testing beam characteristics and to verify the source proper operation. The SPIDER beam will be characterised by the instrumented calorimeter STRIKE, whose main components are one-directional carbon fibre carbon composite tiles. Some prototype tiles have been employed in 2012 as a small-scale version (mini-STRIKE) of the entire system to investigate the features ofmore » the beam from BATMAN at IPP-Garching. As the BATMAN beamlets are superposed at the measurement position, about 1m from the grounded grid, an actively cooled copper mask is located in front of the tiles; holes in the mask create an artificial beamlet structure. Recently the mini-STRIKE has been updated, taking into account the results obtained in the first campaign. In particular the spatial resolution of the system has been improved by increasing the number of the copper mask holes. Moreover a custom measurement system has been realized for the thermocouple signals and employed in BATMAN in view of its use in SPIDER. The present contribution gives a description of the new design of the system as well as of the thermocouple measurements system and its field test. A new series of measurements has been carried out in BATMAN. The BATMAN beam characterisation in different experimental conditions is presented.« less

Fast ignition realization experiment with high-contrast kilo-joule peta-watt LFEX laser and strong external magnetic field

NASA Astrophysics Data System (ADS)

Fujioka, Shinsuke; Arikawa, Yasunobu; Kojima, Sadaoki; Johzaki, Tomoyuki; Nagatomo, Hideo; Sawada, Hiroshi; Lee, Seung Ho; Shiroto, Takashi; Ohnishi, Naofumi; Morace, Alessio; Vaisseau, Xavier; Sakata, Shohei; Abe, Yuki; Matsuo, Kazuki; Farley Law, King Fai; Tosaki, Shota; Yogo, Akifumi; Shigemori, Keisuke; Hironaka, Yoichiro; Zhang, Zhe; Sunahara, Atsushi; Ozaki, Tetsuo; Sakagami, Hitoshi; Mima, Kunioki; Fujimoto, Yasushi; Yamanoi, Kohei; Norimatsu, Takayoshi; Tokita, Shigeki; Nakata, Yoshiki; Kawanaka, Junji; Jitsuno, Takahisa; Miyanaga, Noriaki; Nakai, Mitsuo; Nishimura, Hiroaki; Shiraga, Hiroyuki; Kondo, Kotaro; Bailly-Grandvaux, Mathieu; Bellei, Claudio; Santos, João Jorge; Azechi, Hiroshi

2016-05-01

A petawatt laser for fast ignition experiments (LFEX) laser system [N. Miyanaga et al., J. Phys. IV France 133, 81 (2006)], which is currently capable of delivering 2 kJ in a 1.5 ps pulse using 4 laser beams, has been constructed beside the GEKKO-XII laser facility for demonstrating efficient fast heating of a dense plasma up to the ignition temperature under the auspices of the Fast Ignition Realization EXperiment (FIREX) project [H. Azechi et al., Nucl. Fusion 49, 104024 (2009)]. In the FIREX experiment, a cone is attached to a spherical target containing a fuel to prevent a corona plasma from entering the path of the intense heating LFEX laser beams. The LFEX laser beams are focused at the tip of the cone to generate a relativistic electron beam (REB), which heats a dense fuel core generated by compression of a spherical deuterized plastic target induced by the GEKKO-XII laser beams. Recent studies indicate that the current heating efficiency is only 0.4%, and three requirements to achieve higher efficiency of the fast ignition (FI) scheme with the current GEKKO and LFEX systems have been identified: (i) reduction of the high energy tail of the REB; (ii) formation of a fuel core with high areal density using a limited number (twelve) of GEKKO-XII laser beams as well as a limited energy (4 kJ of 0.53-μm light in a 1.3 ns pulse); (iii) guiding and focusing of the REB to the fuel core. Laser-plasma interactions in a long-scale plasma generate electrons that are too energetic to efficiently heat the fuel core. Three actions were taken to meet the first requirement. First, the intensity contrast of the foot pulses to the main pulses of the LFEX was improved to >109. Second, a 5.5-mm-long cone was introduced to reduce pre-heating of the inner cone wall caused by illumination of the unconverted 1.053-μm light of implosion beam (GEKKO-XII). Third, the outside of the cone wall was coated with a 40-μm plastic layer to protect it from the pressure caused by imploding plasma. Following the above improvements, conversion of 13% of the LFEX laser energy to a low energy portion of the REB, whose slope temperature is 0.7 MeV, which is close to the ponderomotive scaling value, was achieved. To meet the second requirement, the compression of a solid spherical ball with a diameter of 200-μm to form a dense core with an areal density of ˜0.07 g/cm2 was induced by a laser-driven spherically converging shock wave. Converging shock compression is more hydrodynamically stable compared to shell implosion, while a hot spot cannot be generated with a solid ball target. Solid ball compression is preferable also for compressing an external magnetic field to collimate the REB to the fuel core, due to the relatively small magnetic Reynolds number of the shock compressed region. To meet the third requirement, we have generated a strong kilo-tesla magnetic field using a laser-driven capacitor-coil target. The strength and time history of the magnetic field were characterized with proton deflectometry and a B-dot probe. Guidance of the REB using a 0.6-kT field in a planar geometry has been demonstrated at the LULI 2000 laser facility. In a realistic FI scenario, a magnetic mirror is formed between the REB generation point and the fuel core. The effects of the strong magnetic field on not only REB transport but also plasma compression were studied using numerical simulations. According to the transport calculations, the heating efficiency can be improved from 0.4% to 4% by the GEKKO and LFEX laser system by meeting the three requirements described above. This efficiency is scalable to 10% of the heating efficiency by increasing the areal density of the fuel core.

Fast ignition realization experiment with high-contrast kilo-joule peta-watt LFEX laser and strong external magnetic field

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fujioka, Shinsuke, E-mail: sfujioka@ile.osaka-u.ac.jp; Arikawa, Yasunobu; Kojima, Sadaoki

A petawatt laser for fast ignition experiments (LFEX) laser system [N. Miyanaga et al., J. Phys. IV France 133, 81 (2006)], which is currently capable of delivering 2 kJ in a 1.5 ps pulse using 4 laser beams, has been constructed beside the GEKKO-XII laser facility for demonstrating efficient fast heating of a dense plasma up to the ignition temperature under the auspices of the Fast Ignition Realization EXperiment (FIREX) project [H. Azechi et al., Nucl. Fusion 49, 104024 (2009)]. In the FIREX experiment, a cone is attached to a spherical target containing a fuel to prevent a corona plasma frommore » entering the path of the intense heating LFEX laser beams. The LFEX laser beams are focused at the tip of the cone to generate a relativistic electron beam (REB), which heats a dense fuel core generated by compression of a spherical deuterized plastic target induced by the GEKKO-XII laser beams. Recent studies indicate that the current heating efficiency is only 0.4%, and three requirements to achieve higher efficiency of the fast ignition (FI) scheme with the current GEKKO and LFEX systems have been identified: (i) reduction of the high energy tail of the REB; (ii) formation of a fuel core with high areal density using a limited number (twelve) of GEKKO-XII laser beams as well as a limited energy (4 kJ of 0.53-μm light in a 1.3 ns pulse); (iii) guiding and focusing of the REB to the fuel core. Laser–plasma interactions in a long-scale plasma generate electrons that are too energetic to efficiently heat the fuel core. Three actions were taken to meet the first requirement. First, the intensity contrast of the foot pulses to the main pulses of the LFEX was improved to >10{sup 9}. Second, a 5.5-mm-long cone was introduced to reduce pre-heating of the inner cone wall caused by illumination of the unconverted 1.053-μm light of implosion beam (GEKKO-XII). Third, the outside of the cone wall was coated with a 40-μm plastic layer to protect it from the pressure caused by imploding plasma. Following the above improvements, conversion of 13% of the LFEX laser energy to a low energy portion of the REB, whose slope temperature is 0.7 MeV, which is close to the ponderomotive scaling value, was achieved. To meet the second requirement, the compression of a solid spherical ball with a diameter of 200-μm to form a dense core with an areal density of ∼0.07 g/cm{sup 2} was induced by a laser-driven spherically converging shock wave. Converging shock compression is more hydrodynamically stable compared to shell implosion, while a hot spot cannot be generated with a solid ball target. Solid ball compression is preferable also for compressing an external magnetic field to collimate the REB to the fuel core, due to the relatively small magnetic Reynolds number of the shock compressed region. To meet the third requirement, we have generated a strong kilo-tesla magnetic field using a laser-driven capacitor-coil target. The strength and time history of the magnetic field were characterized with proton deflectometry and a B-dot probe. Guidance of the REB using a 0.6-kT field in a planar geometry has been demonstrated at the LULI 2000 laser facility. In a realistic FI scenario, a magnetic mirror is formed between the REB generation point and the fuel core. The effects of the strong magnetic field on not only REB transport but also plasma compression were studied using numerical simulations. According to the transport calculations, the heating efficiency can be improved from 0.4% to 4% by the GEKKO and LFEX laser system by meeting the three requirements described above. This efficiency is scalable to 10% of the heating efficiency by increasing the areal density of the fuel core.« less

Intense highly charged ion beam production and operation with a superconducting electron cyclotron resonance ion source

NASA Astrophysics Data System (ADS)

Zhao, H. W.; Sun, L. T.; Guo, J. W.; Lu, W.; Xie, D. Z.; Hitz, D.; Zhang, X. Z.; Yang, Y.

2017-09-01

The superconducting electron cyclotron resonance ion source with advanced design in Lanzhou (SECRAL) is a superconducting-magnet-based electron cyclotron resonance ion source (ECRIS) for the production of intense highly charged heavy ion beams. It is one of the best performing ECRISs worldwide and the first superconducting ECRIS built with an innovative magnet to generate a high strength minimum-B field for operation with heating microwaves up to 24-28 GHz. Since its commissioning in 2005, SECRAL has so far produced a good number of continuous wave intensity records of highly charged ion beams, in which recently the beam intensities of 40Ar+ and 129Xe26+ have, for the first time, exceeded 1 emA produced by an ion source. Routine operations commenced in 2007 with the Heavy Ion accelerator Research Facility in Lanzhou (HIRFL), China. Up to June 2017, SECRAL has been providing more than 28,000 hours of highly charged heavy ion beams to the accelerator demonstrating its great capability and reliability. The great achievement of SECRAL is accumulation of numerous technical advancements, such as an innovative magnetic system and an efficient double-frequency (24 +18 GHz ) heating with improved plasma stability. This article reviews the development of SECRAL and production of intense highly charged ion beams by SECRAL focusing on its unique magnet design, source commissioning, performance studies and enhancements, beam quality and long-term operation. SECRAL development and its performance studies representatively reflect the achievements and status of the present ECR ion source, as well as the ECRIS impacts on HIRFL.

ORNL-TNS/PEPR overall heating requirements

DOE Office of Scientific and Technical Information (OSTI.GOV)

Peng, Y. K.M.; Rome, J. A.

1977-01-01

The ORNL TNS/PEPR studies have the objectives of (1) leading to a system that demonstrates the fusion reactor core in the mid-to-late 1980's and extrapolates to an economic tokamak power reactor, and (2) providing a near-term focus for the scientific and technological programs toward the power reactor. This discussion of the overall heating requirements for the ORNL TNS/PEPR is concerned with the neutral beams as the primary heating method, the electron-cyclotron resonance (ECR) heating at a lower power level for profile control, and the upper hybrid resonance (UHR) initiation and preheating of currentless plasmas to reduce current start-up loop voltagemore » (V/sub l/) requirements.« less

On the influence of monochromator thermal deformations on X-ray focusing

DOE PAGES

Antimonov, M. A.; Khounsary, A. M.; Sandy, A. R.; ...

2016-03-02

A cooled double crystal monochromator system is used on many high heat load X-ray synchrotron radiation beamlines in order to select, by diffraction, a narrow spectrum of the beam. Thermal deformation of the first crystal monochromator – and the potential loss of beam brightness – is often a concern. However, if downstream beam focusing is planned, the lensing effect of the monochromator must be considered even if thermal deformations are small. In this paper we report on recent experiments at an Advanced Photon Source (APS) beamline that focuses the X-ray beam using compound refractive lenses downstream of an X-ray monochromatormore » system. Increasing the X-ray beam power by increasing the storage ring current from 100 mA to 130 mA resulted in an effective doubling of the focal distance. We show quantitatively that this is due to a lensing effect of the distorted monochromator that results in the creation of a virtual source downstream of the actual source. Lastly, an analysis of the defocusing and options to mitigate this effect are explored.« less

Effects of realistic heat straightening repair on the properties and serviceability of damaged steel beam bridges.

DOT National Transportation Integrated Search

2012-02-01

The permanent deformations in steel beam bridges caused by collision with high profile vehicles can be repaired by heat straightening, : which is a structurally efficient and costeffective repair process developed by many engineers over the years....

Development of neutral beam injection system by use of washer gun plasma source

NASA Astrophysics Data System (ADS)

Imanaka, Heizo; Kajiya, Hirotaka; Nemoto, Yuichi; Azuma, Akiyoshi; Asai, Tomoaki; Yamada, Takuma; Inomoto, Michiaki; Ono, Yasushi

2008-11-01

For the past ten years, we have been investigating high-beta Spherical Tokamaks (ST) formation using reconnection heating of their axial merging in the TS-4 experiment, University of Tokyo. The produced ST was observed to have the maximum beta of 50-60% right after the merging of two STs. A key issue after the formation is to maintain the produced high-beta ST over 100 Alfven times for its stability check. A new low-cost pulsed neutral beam injection (NBI) system has been arranged for its sustainment experiment. Its advantages are 1) low voltage (15kV for low-field side of ST) and high current (20A), 2) maintenance-free, 3) low-cost. The conventional filament plasma source was replaced by the washer gun to realize air-cooled and maintenance free NBI system. In its startup experiment, we already extracted the maximum beam current of 3.7A for then acceleration voltage of 10kV successfully. This result suggests that the increase in the acceleration voltage and several conditioning work will realize its designed beam parameters of 15kV, 20A.

Focused US system for MR imaging-guided tumor ablation.

PubMed

Cline, H E; Hynynen, K; Watkins, R D; Adams, W J; Schenck, J F; Ettinger, R H; Freund, W R; Vetro, J P; Jolesz, F A

1995-03-01

To measure the performance characteristics of a focused ultrasound (US) system for magnetic resonance (MR) imaging-guided tumor ablation. The authors constructed a focused US system for MR imaging-guided tumor ablation. The location of the heated region and thermal dose were monitored with temperature-sensitive MR images obtained in phantoms and rabbit skeletal muscle after application of each sonic pulse. The region heated by the focused ultrasound beam was within 1 mm of that observed on temperature-sensitive fast gradient-echo MR images of in vivo rabbit skeletal muscle. Analysis of heat flow and the rate of coagulation necrosis provided an estimate of the size of the ablated region that was in agreement with experimental findings. MR imaging provides target definition and control for thermal therapy in regions of variable perfusion or in tissues that are not well characterized.

The Beam Forming Numerical Simulation for High Power Neutral Injector

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sorokin, A.; Deichuli, P.; Ivanov, A.

2005-01-15

High power neutral beam injector START-4 for plasma heating has been described. The distinctive features of the injector are comparatively large initial beam aperture (200 mm) and multi holes grids with the large numbers of the holes (more than 3000). A significant focusing is realized to a beam diameter 50 mm at a length 1.2 m. The disadvantage of the multi holes optic is low transparency, which decreases the efficiency of plasma source and makes worse vacuum conditions in the source. The possible decisions of these problems are using ion-optical systems (IOS) with enlarged diameter of holes and, also, applicationmore » IOS with the azimuthal-slit holes structure. Numerical simulation and test experiments have been carried out for investigation of the ability such IOS geometries.« less

Design study of primary ion provider for relativistic heavy ion collider electron beam ion source.

PubMed

Kondo, K; Kanesue, T; Tamura, J; Okamura, M

2010-02-01

Brookhaven National Laboratory has developed the new preinjector system, electron beam ion source (EBIS) for relativistic heavy ion collider (RHIC) and National Aeronautics and Space Administration Space Radiation Laboratory. Design of primary ion provider is an essential problem since it is required to supply beams with different ion species to multiple users simultaneously. The laser ion source with a defocused laser can provide a low charge state and low emittance ion beam, and is a candidate for the primary ion source for RHIC-EBIS. We show a suitable design with appropriate drift length and solenoid, which helps to keep sufficient total charge number with longer pulse length. The whole design of primary ion source, as well as optics arrangement, solid targets configuration and heating about target, is presented.

Physics design of the injector source for ITER neutral beam injector (invited).

PubMed

Antoni, V; Agostinetti, P; Aprile, D; Cavenago, M; Chitarin, G; Fonnesu, N; Marconato, N; Pilan, N; Sartori, E; Serianni, G; Veltri, P

2014-02-01

Two Neutral Beam Injectors (NBI) are foreseen to provide a substantial fraction of the heating power necessary to ignite thermonuclear fusion reactions in ITER. The development of the NBI system at unprecedented parameters (40 A of negative ion current accelerated up to 1 MV) requires the realization of a full scale prototype, to be tested and optimized at the Test Facility under construction in Padova (Italy). The beam source is the key component of the system and the design of the multi-grid accelerator is the goal of a multi-national collaborative effort. In particular, beam steering is a challenging aspect, being a tradeoff between requirements of the optics and real grids with finite thickness and thermo-mechanical constraints due to the cooling needs and the presence of permanent magnets. In the paper, a review of the accelerator physics and an overview of the whole R&D physics program aimed to the development of the injector source are presented.

Photothermal camera port accessory for microscopic thermal diffusivity imaging

NASA Astrophysics Data System (ADS)

Escola, Facundo Zaldívar; Kunik, Darío; Mingolo, Nelly; Martínez, Oscar Eduardo

2016-06-01

The design of a scanning photothermal accessory is presented, which can be attached to the camera port of commercial microscopes to measure thermal diffusivity maps with micrometer resolution. The device is based on the thermal expansion recovery technique, which measures the defocusing of a probe beam due to the curvature induced by the local heat delivered by a focused pump beam. The beam delivery and collecting optics are built using optical fiber technology, resulting in a robust optical system that provides collinear pump and probe beams without any alignment adjustment necessary. The quasiconfocal configuration for the signal collection using the same optical fiber sets very restrictive conditions on the positioning and alignment of the optical components of the scanning unit, and a detailed discussion of the design equations is presented. The alignment procedure is carefully described, resulting in a system so robust and stable that no further alignment is necessary for the day-to-day use, becoming a tool that can be used for routine quality control, operated by a trained technician.

Generation of high charge state metal ion beams by electron cyclotron resonance heating of vacuum arc plasma in cusp trap.

PubMed

Nikolaev, A G; Savkin, K P; Oks, E M; Vizir, A V; Yushkov, G Yu; Vodopyanov, A V; Izotov, I V; Mansfeld, D A

2012-02-01

A method for generating high charge state heavy metal ion beams based on high power microwave heating of vacuum arc plasma confined in a magnetic trap under electron cyclotron resonance conditions has been developed. A feature of the work described here is the use of a cusp magnetic field with inherent "minimum-B" structure as the confinement geometry, as opposed to a simple mirror device as we have reported on previously. The cusp configuration has been successfully used for microwave heating of gas discharge plasma and extraction from the plasma of highly charged, high current, gaseous ion beams. Now we use the trap for heavy metal ion beam generation. Two different approaches were used for injecting the vacuum arc metal plasma into the trap--axial injection from a miniature arc source located on-axis near the microwave window, and radial injection from sources mounted radially at the midplane of the trap. Here, we describe preliminary results of heating vacuum arc plasma in a cusp magnetic trap by pulsed (400 μs) high power (up to 100 kW) microwave radiation at 37.5 GHz for the generation of highly charged heavy metal ion beams.

The New S-RAM Air Variable Compressor/Expander for Heat Pump and Waste Heat to Power Application

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dehoff, Ryan R; Jestings, Lee; Conde, Ricardo

S-RAM Dynamics (S-RAM) has designed an innovative heat pump system targeted for commercial and industrial applications. This new heat pump system is more efficient than anything currently on the market and utilizes air as the refrigerant instead of hydrofluorocarbon (HFC) refrigerants, leading to lower operating costs, minimal environmental costs or concerns, and lower maintenance costs. The heat pumps will be manufactured in the United States. This project was aimed at determining the feasibility of utilizing additive manufacturing to make the heat exchanger device for the new heat pump system. ORNL and S-RAM Dynamics collaborated on determining the prototype performance andmore » subsequently printing of the prototype using additive manufacturing. Complex heat exchanger designs were fabricated using the Arcam electron beam melting (EBM) powder bed technology using Ti-6Al-4V material. An ultrasonic welding system was utilized in order to remove the powder from the small openings of the heat exchanger. The majority of powder in the small chambers was removed, however, the amount of powder remaining in the heat exchanger was a function of geometry. Therefore, only certain geometries of heat exchangers could be fabricated. SRAM Dynamics evaluated a preliminary heat exchanger design. Although the results of the additive manufacturing of the heat exchanger were not optimum, a less complex geometry was demonstrated. A sleeve valve was used as a demonstration piece, as engine designs from S-RAM Dynamics require the engine to have a very high density. Preliminary designs of this geometry were successfully fabricated using the EBM technology.« less

Preliminary design of the beam screen cooling for the Future Circular Collider of hadron beams

NASA Astrophysics Data System (ADS)

Kotnig, C.; Tavian, L.

2015-12-01

Following recommendations of the recent update of the European strategy in particle physics, CERN has undertaken an international study of possible future circular colliders beyond the LHC. This study considers an option for a very high energy (100 TeV) hadron-hadron collider located in a quasi-circular underground tunnel having a circumference of 80 to 100 km. The synchrotron radiation emitted by the high-energy hadron beam increases by more than two orders of magnitude compared to the LHC. To reduce the entropic load on the superconducting magnets’ refrigeration system, beam screens are indispensable to extract the heat load at a higher temperature level. After illustrating the decisive constraints of the beam screen's refrigeration design, this paper presents a preliminary design of the length of a continuous cooling loop comparing helium and neon, for different cooling channel geometries with emphasis on the cooling length limitations and the exergetic efficiency.

Status of the ion sources developments for the Spiral2 project at GANILa)

NASA Astrophysics Data System (ADS)

Lehérissier, P.; Bajeat, O.; Barué, C.; Canet, C.; Dubois, M.; Dupuis, M.; Flambard, J. L.; Frigot, R.; Jardin, P.; Leboucher, C.; Lemagnen, F.; Maunoury, L.; Osmond, B.; Pacquet, J. Y.; Pichard, A.; Thuillier, T.; Peaucelle, C.

2012-02-01

The SPIRAL 2 facility is now under construction and will deliver either stable or radioactive ion beams. First tests of nickel beam production have been performed at GANIL with a new version of the large capacity oven, and a calcium beam has been produced on the heavy ion low energy beam transport line of SPIRAL 2, installed at LPSC Grenoble. For the production of radioactive beams, several target/ion-source systems (TISSs) are under development at GANIL as the 2.45 GHz electron cyclotron resonance ion source, the surface ionization source, and the oven prototype for heating the uranium carbide target up to 2000 °C. The existing test bench has been upgraded for these developments and a new one, dedicated for the validation of the TISS before mounting in the production module, is under design. Results and current status of these activities are presented.

High-energy electron beams for ceramic joining

NASA Astrophysics Data System (ADS)

Turman, Bob N.; Glass, S. J.; Halbleib, J. A.; Helmich, D. R.; Loehman, Ron E.; Clifford, Jerome R.

1995-03-01

Joining of structural ceramics is possible using high melting point metals such as Mo and Pt that are heated with a high energy electron beam, with the potential for high temperature joining. A 10 MeV electron beam can penetrate through 1 cm of ceramic, offering the possibility of buried interface joining. Because of transient heating and the lower heat capacity of the metal relative to the ceramic, a pulsed high power beam has the potential for melting the metal without decomposing or melting the ceramic. We have demonstrated the feasibility of the process with a series of 10 MeV, 1 kW electron beam experiments. Shear strengths up to 28 MPa have been measured. This strength is comparable to that reported in the literature for bonding silicon nitride (Si3N4) to molybdenum with copper-silver-titanium braze, but weaker than that reported for Si3N4 - Si3N4 with gold-nickel braze. The bonding mechanism appears to be formation of a thin silicide layer. Beam damage to the Si3N4 was also assessed.

Laser production and heating of plasma for MHD application

NASA Technical Reports Server (NTRS)

Jalufka, N. W.

1988-01-01

Experiments have been made on the production and heating of plasmas by the absorption of laser radiation. These experiments were performed to ascertain the feasibility of using laser-produced or laser-heated plasmas as the input for a magnetohydrodynamic (MHD) generator. Such a system would have a broad application as a laser-to-electricity energy converter for space power transmission. Experiments with a 100-J-pulsed CO2 laser were conducted to investigate the breakdown of argon gas by a high-intensity laser beam, the parameters (electron density and temperature) of the plasma produced, and the formation and propagation of laser-supported detonation (LSD) waves. Experiments were also carried out using a 1-J-pulsed CO2 laser to heat the plasma produced in a shock tube. The shock-tube hydrogen plasma reached electron densities of approximately 10 to the 17th/cu cm and electron temperatures of approximately 1 eV. Absorption of the CO2 laser beam by the plasma was measured, and up to approximately 100 percent absorption was observed. Measurements with a small MHD generator showed that the energy extraction efficiency could be very large with values up to 56 percent being measured.

The Electron Bernstein Waves Heating Project In The TJ-II Stellarator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fernandez, A.; Cappa, A.; Castejon, F.

2007-09-28

TJ-II is a middle sized flexible Heliac operating in Madrid, whose plasmas are created and heated by ECRH via two 300 kW gyrotrons at second harmonic X-mode (53.2 GHz). Neutral beam injection is used for second phase heating. Since the cut off density for the 2nd harmonic X-mode (n{sub c} = 1.7x10 {sup 19} m{sup -3}) is reached during NBI, EBWs are considered both for providing additional heating after NBI switch on and to perform kinetic studies in high-density plasmas. Previous work has shown that the most suitable scheme for launching EBWs in TJ-II is O-X-B mode conversion, which hasmore » acceptable heating efficiency for central densities above 1.2x10{sup 19} m{sup -3}, with an operating frequency of 28 GHz. In this work, the most relevant theoretical calculations are presented, including the relativistic effects both in ray trajectory and absorption, as well as the results of the optimization of the beam parameters that provide the maximum O-X conversion efficiency at the critical layer. A system based on a 28 GHz-100 ms diode gyrotron will be used to deliver 300 kW through a corrugated waveguide. The microwave beam is directed and focused by a steerable mirror located inside the vacuum vessel. A diagnostic for measuring the EBW emission has been designed and tested on the bench. It uses a section of corrugated waveguide and a glass lens to focus the emission from the plasma into the aperture of a dual polarized quad-ridged horn. It will allow us to determine the EBW mode conversion efficiency, and also provides an indication of the electron temperature evolution in overdense plasmas.« less

Methods for slow axis beam quality improvement of high power broad area diode lasers

NASA Astrophysics Data System (ADS)

An, Haiyan; Xiong, Yihan; Jiang, Ching-Long J.; Schmidt, Berthold; Treusch, Georg

2014-03-01

For high brightness direct diode laser systems, it is of fundamental importance to improve the slow axis beam quality of the incorporated laser diodes regardless what beam combining technology is applied. To further advance our products in terms of increased brightness at a high power level, we must optimize the slow axis beam quality despite the far field blooming at high current levels. The later is caused predominantly by the built-in index step in combination with the thermal lens effect. Most of the methods for beam quality improvements reported in publications sacrifice the device efficiency and reliable output power. In order to improve the beam quality as well as maintain the efficiency and reliable output power, we investigated methods of influencing local heat generation to reduce the thermal gradient across the slow axis direction, optimizing the built-in index step and discriminating high order modes. Based on our findings, we have combined different methods in our new device design. Subsequently, the beam parameter product (BPP) of a 10% fill factor bar has improved by approximately 30% at 7 W/emitter without efficiency penalty. This technology has enabled fiber coupled high brightness multi-kilowatt direct diode laser systems. In this paper, we will elaborate on the methods used as well as the results achieved.

Long-pulse beam acceleration of MeV-class H(-) ion beams for ITER NB accelerator.

PubMed

Umeda, N; Kashiwagi, M; Taniguchi, M; Tobari, H; Watanabe, K; Dairaku, M; Yamanaka, H; Inoue, T; Kojima, A; Hanada, M

2014-02-01

In order to realize neutral beam systems in International Thermonuclear Experimental Reactor whose target is to produce a 1 MeV, 200 A/m(2) during 3600 s D(-) ion beam, the electrostatic five-stages negative ion accelerator so-called "MeV accelerator" has been developed at Japan Atomic Energy Agency. To extend pulse length, heat load of the acceleration grids was reduced by controlling the ion beam trajectory. Namely, the beam deflection due to the residual magnetic field of filter magnet was suppressed with the newly developed extractor with a 0.5 mm off-set aperture displacement. The new extractor improved the deflection angle from 6 mrad to 1 mrad, resulting in the reduction of direct interception of negative ions from 23% to 15% of the total acceleration power, respectively. As a result, the pulse length of 130 A/m(2), 881 keV H(-) ion beam has been successfully extended from a previous value of 0.4 s to 8.7 s. This is the first long pulse negative ion beam acceleration over 100 MW/m(2).

Heat pipe cooling of power processing magnetics

NASA Technical Reports Server (NTRS)

Hansen, I. G.; Chester, M. S.

1979-01-01

A heat pipe cooled transformer and input filter were developed for the 2.4 kW beam supply of a 30 cm ion thruster system. This development yielded a mass reduction of 40% (1.76 kg) and lower mean winding temperature (20 C lower). While these improvements are significant, preliminary designs predict even greater benefits to be realized at higher power. The design details are presented along with the results of thermal vacuum operation and the component performance in a 3 kW breadboard power processor.

The Nike Laser Facility and its Capabilities

NASA Astrophysics Data System (ADS)

Serlin, V.; Aglitskiy, Y.; Chan, L. Y.; Karasik, M.; Kehne, D. M.; Oh, J.; Obenschain, S. P.; Weaver, J. L.

2013-10-01

The Nike laser is a 56-beam krypton fluoride (KrF) system that provides 3 to 4 kJ of laser energy on target. The laser uses induced spatial incoherence to achieve highly uniform focal distributions. 44 beams are overlapped onto target with peak intensities up to 1016 W/cm2. The effective time-averaged illumination nonuniformity is < 0 . 2 %. Nike produces highly uniform ablation pressures on target allowing well-controlled experiments at pressures up to 20 Mbar. The other 12 laser beams are used to generate diagnostic x-rays radiographing the primary laser-illuminated target. The facility includes a front end that generates the desired temporal and spatial laser profiles, two electron-beam pumped KrF amplifiers, a computer-controlled optical system, and a vacuum target chamber for experiments. Nike is used to study the physics and technology issues of direct-drive laser fusion, such as, hydrodynamic and laser-plasma instabilities, studies of the response of materials to extreme pressures, and generation of X rays from laser-heated targets. Nike features a computer-controlled data acquisition system, high-speed, high-resolution x-ray and visible imaging systems, x-ray and visible spectrometers, and cryogenic target capability. Work supported by DOE/NNSA.

The effect of nonlinear propagation on heating of tissue: A numerical model of diagnostic ultrasound beams

NASA Astrophysics Data System (ADS)

Cahill, Mark D.; Humphrey, Victor F.; Doody, Claire

2000-07-01

Thermal safety indices for diagnostic ultrasound beams are calculated under the assumption that the sound propagates under linear conditions. A non-axisymmetric finite difference model is used to solve the KZK equation, and so to model the beam of a diagnostic scanner in pulsed Doppler mode. Beams from both a uniform focused rectangular source and a linear array are considered. Calculations are performed in water, and in attenuating media with tissue-like characteristics. Attenuating media are found to exhibit significant nonlinear effects for finite-amplitude beams. The resulting loss of intensity by the beam is then used as the source term in a model of tissue heating to estimate the maximum temperature rises. These are compared with the thermal indices, derived from the properties of the water-propagated beams.

Time-to-burnout data for a prototypical ITER divertor tube during a simulated loss of flow accident

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marshall, T.D.; Watson, R.D.; McDonald, J.M.

The Loss of Flow Accident (LOFA) is a serious safety concern for the International Thermonuclear Experimental Reactor (ITER) as it has been suggested that greater than 100 seconds are necessary to safely shutdown the plasma when ITER is operating at full power. In this experiment, the thermal response of a prototypical ITER divertor tube during a simulated LOFA was studied. The divertor tube was fabricated from oxygen-free high-conductivity copper to have a square geometry with a circular coolant channel. The coolant channel inner diameter was 0.77 cm, the heated length was 4.0 cm, and the heated width was 1.6 cm.more » The mockup did not feature any flow enhancement techniques, i.e., swirl tape, helical coils, or internal fins. One-sided surface heating of the mockup was accomplished through the use of the 30 kW Sandia Electron Beam Test System. After reaching steady state temperatures in the mockup, as determined by two Type-K thermocouples installed 0.5 mm beneath the heated surface, the coolant pump was manually tripped off and the coolant flow allowed to naturally coast down. Electron beam heating continued after the pump trip until the divertor tube`s heated surface exhibited the high temperature transient normally indicative of rapidly approaching burnout. Experimental data showed that time-to-burnout increases proportionally with increasing inlet velocity and decreases proportionally with increasing incident heat flux.« less

Weak light emission of soft tissues induced by heating

NASA Astrophysics Data System (ADS)

Spinelli, Antonello E.; Durando, Giovanni; Boschi, Federico

2018-04-01

The main goal of this work is to show that soft tissue interaction with high-intensity focused ultrasound (HIFU) or direct heating leads to a weak light emission detectable using a small animal optical imaging system. Our results show that the luminescence signal is detectable after 30 min of heating, resembling the time scale of delayed luminescence. The imaging of a soft tissue after heating it using an HIFU field shows that the luminescence pattern closely matches the shape of the cone typical of the HIFU beam. We conclude that heating a soft tissue using two different sources leads to the emission of a weak luminescence signal from the heated region with a decay half-life of a few minutes (4 to 6 min). The origin of such light emission needs to be further investigated.

Spatial calibration of a tokamak neutral beam diagnostic using in situ neutral beam emission

DOE PAGES

Chrystal, Colin; Burrell, Keith H.; Grierson, Brian A.; ...

2015-10-20

Neutral beam injection is used in tokamaks to heat, apply torque, drive non-inductive current, and diagnose plasmas. Neutral beam diagnostics need accurate spatial calibrations to benefit from the measurement localization provided by the neutral beam. A new technique has been developed that uses in-situ measurements of neutral beam emission to determine the spatial location of the beam and the associated diagnostic views. This technique was developed to improve the charge exchange recombination diagnostic (CER) at the DIII-D tokamak and uses measurements of the Doppler shift and Stark splitting of neutral beam emission made by that diagnostic. These measurements contain informationmore » about the geometric relation between the diagnostic views and the neutral beams when they are injecting power. This information is combined with standard spatial calibration measurements to create an integrated spatial calibration that provides a more complete description of the neutral beam-CER system. The integrated spatial calibration results are very similar to the standard calibration results and derived quantities from CER measurements are unchanged within their measurement errors. Lastly, the methods developed to perform the integrated spatial calibration could be useful for tokamaks with limited physical access.« less

Spatial calibration of a tokamak neutral beam diagnostic using in situ neutral beam emission

NASA Astrophysics Data System (ADS)

Chrystal, C.; Burrell, K. H.; Grierson, B. A.; Pace, D. C.

2015-10-01

Neutral beam injection is used in tokamaks to heat, apply torque, drive non-inductive current, and diagnose plasmas. Neutral beam diagnostics need accurate spatial calibrations to benefit from the measurement localization provided by the neutral beam. A new technique has been developed that uses in situ measurements of neutral beam emission to determine the spatial location of the beam and the associated diagnostic views. This technique was developed to improve the charge exchange recombination (CER) diagnostic at the DIII-D tokamak and uses measurements of the Doppler shift and Stark splitting of neutral beam emission made by that diagnostic. These measurements contain information about the geometric relation between the diagnostic views and the neutral beams when they are injecting power. This information is combined with standard spatial calibration measurements to create an integrated spatial calibration that provides a more complete description of the neutral beam-CER system. The integrated spatial calibration results are very similar to the standard calibration results and derived quantities from CER measurements are unchanged within their measurement errors. The methods developed to perform the integrated spatial calibration could be useful for tokamaks with limited physical access.

Susceptor heating device for electron beam brazing

DOEpatents

Antieau, Susan M.; Johnson, Robert G. R.

1999-01-01

A brazing device and method are provided which locally apply a controlled amount of heat to a selected area, within a vacuum. The device brazes two components together with a brazing metal. A susceptor plate is placed in thermal contact with one of the components. A serrated pedestal supports the susceptor plate. When the pedestal and susceptor plate are in place, an electron gun irradiates an electron beam at the susceptor plate such that the susceptor plate is sufficiently heated to transfer heat through the one component and melt the brazing metal.

Conjugate Heat Transfer and Thermal Mechanical Analysis for Liquid Metal Targets for High Power Electron Beams.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Olivas, Eric Richard

2016-02-26

A conjugate heat transfer and thermal structural analysis was completed, with the objective of determining the following: Lead bismuth eutectic (LBE) peak temperature, free convective velocity patterns in the LBE, peak beam window temperature, and thermal stress/deformation in the window.

Temperature-gated thermal rectifier for active heat flow control.

PubMed

Zhu, Jia; Hippalgaonkar, Kedar; Shen, Sheng; Wang, Kevin; Abate, Yohannes; Lee, Sangwook; Wu, Junqiao; Yin, Xiaobo; Majumdar, Arun; Zhang, Xiang

2014-08-13

Active heat flow control is essential for broad applications of heating, cooling, and energy conversion. Like electronic devices developed for the control of electric power, it is very desirable to develop advanced all-thermal solid-state devices that actively control heat flow without consuming other forms of energy. Here we demonstrate temperature-gated thermal rectification using vanadium dioxide beams in which the environmental temperature actively modulates asymmetric heat flow. In this three terminal device, there are two switchable states, which can be regulated by global heating. In the "Rectifier" state, we observe up to 28% thermal rectification. In the "Resistor" state, the thermal rectification is significantly suppressed (<1%). To the best of our knowledge, this is the first demonstration of solid-state active-thermal devices with a large rectification in the Rectifier state. This temperature-gated rectifier can have substantial implications ranging from autonomous thermal management of heating and cooling systems to efficient thermal energy conversion and storage.

40 CFR 63.987 - Flare requirements.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Emission Standards for Closed Vent Systems, Control Devices, Recovery Devices and Routing to a Fuel Gas... the additional cycles. (ii) The net heating value of the gas being combusted in a flare shall be..., ultra-violet beam sensor, or infrared sensor) capable of continuously detecting that at least one pilot...

Variable orifice using an iris shutter

DOEpatents

Beeman, Raymond; Brajkovich, Steven J.

1978-01-01

A variable orifice forming mechanism utilizing an iris shutter arrangement adapted to control gas flow, conductance in vacuum systems, as a heat shield for furnace windows, as a beam shutter in sputtering operations, and in any other application requiring periodic or continuously-variable control of material, gas, or fluid flow.

Chevron beam dump for ITER edge Thomson scattering system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yatsuka, E.; Hatae, T.; Bassan, M.

This paper contains the design of the beam dump for the ITER edge Thomson scattering system and mainly concerns its lifetime under the harsh thermal and electromagnetic loads as well as tight space allocation. The lifetime was estimated from the multi-pulse laser-induced damage threshold. In order to extend its lifetime, the structure of the beam dump was optimized. A number of bent sheets aligned parallel in the beam dump form a shape called a chevron which enables it to avoid the concentration of the incident laser pulse energy. The chevron beam dump is expected to withstand thermal loads due tomore » nuclear heating, radiation from the plasma, and numerous incident laser pulses throughout the entire ITER project with a reasonable margin for the peak factor of the beam profile. Structural analysis was also carried out in case of electromagnetic loads during a disruption. Moreover, detailed issues for more accurate assessments of the beam dump's lifetime are clarified. Variation of the bi-directional reflection distribution function (BRDF) due to erosion by or contamination of neutral particles derived from the plasma is one of the most critical issues that needs to be resolved. In this paper, the BRDF was assumed, and the total amount of stray light and the absorbed laser energy profile on the beam dump were evaluated.« less

Simulations of far-field optical beam quality influenced by the thermal distortion of the secondary mirror for high-power laser system

NASA Astrophysics Data System (ADS)

Guo, Ruhai; Chen, Ning; Zhuang, Xinyu; Wang, Bing

2015-02-01

In order to research the influence on the beam quality due to thermal deformation of the secondary mirror in the high power laser system, the theoretical simulation study is performed. Firstly, three typical laser power 10kW, 50kW and 100kW with the wavelength 1.064μm are selected to analyze thermal deformation of mirror through the finite element analyze of thermodynamics instantaneous method. Then the wavefront aberration can be calculated by ray-tracing theory. Finally, focus spot radius，beam quality (BQ) of far-filed beam can be calculated and comparably analyzed by Fresnel diffraction integration. The simulation results show that with the increasing laser power, the optical aberration of beam director gets worse, the far-field optical beam quality decrease, which makes the laser focus spot broadening and the peak optical intensity of center decreasing dramatically. Comparing the clamping ring and the three-point clamping, the former is better than the latter because the former only induces the rotation symmetric deformation and the latter introduces additional astigmatism. The far-field optical beam quality can be improved partly by simply adjusting the distance between the main mirror and the secondary mirror. But the far-field power density is still the one tenth as that without the heat distortion of secondary mirror. These results can also provide the reference to the thermal aberration analyze for high power laser system and can be applied to the field of laser communication system and laser weapon etc.

Measurement of type-I edge localized mode pulse propagation in scrape-off layer using optical system of motional Stark effect diagnostics in JT-60U

DOE Office of Scientific and Technical Information (OSTI.GOV)

Suzuki, T.; Oyama, N.; Asakura, N.

2010-04-15

Propagation of plasma ejected by type-I edge localized mode (ELM) has been measured in scrape-off layer (SOL) of the JT-60U tokamak, using optical system of motional Stark effect (MSE) diagnostics as beam emission spectroscopy (BES) diagnostics through a new technique developed. This MSE/BES system measures D{alpha} emission from heating neutral beam excited by collisions with the ejected plasma, as well as background light (e.g., bremsstrahlung). While spatio-temporal change in the beam emission gives information on propagation of the ejected plasma, the background light that is observed simultaneously in all spatial channels veils the information. In order to separate the beammore » emission and the background light, a two-wavelength detector is newly introduced into the MSE/BES system. The detector observes simultaneously at the same spatial point in two distinct wavelengths using two photomultiplier tubes through two interference filters. One of the filters is adjusted to the central wavelength of the beam emission for the MSE diagnostics, and the other is outside the beam emission spectrum. Eliminating the background light, temporal change in the net beam emission in the SOL has been evaluated. Comparing conditionally averaged beam emission with respect to 594 ELMs in a discharge at five spatial channels (0.02-0.3 m outside the main plasma near equatorial plane), radial velocity of the ELM pulse propagation in SOL is evaluated to be 0.8-1.8 km/s ({approx}1.4 km/s for least-mean-squared fitting).« less

Systems and Methods for Designing and Fabricating Contact-Free Support Structures for Overhang Geometries of Parts in Powder-Bed Metal Additive Manufacturing

NASA Technical Reports Server (NTRS)

Cooper, Kenneth (Inventor); Chou, Yuag-Shan (Inventor)

2017-01-01

Systems and methods are provided for designing and fabricating contact-free support structures for overhang geometries of parts fabricated using electron beam additive manufacturing. One or more layers of un-melted metallic powder are disposed in an elongate gap between an upper horizontal surface of the support structure and a lower surface of the overhang geometry. The powder conducts heat from the overhang geometry to the support structure. The support structure acts as a heat sink to enhance heat transfer and reduce the temperature and severe thermal gradients due to poor thermal conductivity of metallic powders underneath the overhang. Because the support structure is not connected to the part, the support structure can be removed freely without any post-processing step.

Exploring the influence of radiation crosslinking on high-performance hydrogenated acrylonitrile butadiene rubber and polyamide 12 based blends with special reference to heat and oil resistance

NASA Astrophysics Data System (ADS)

Mohammed Reffai, Syed Ismail Syed; Chatterjee, Tuhin; Naskar, Kinsuk

2018-07-01

This paper reports the heat and oil resistant hydrogenated acrylonitrile butadiene rubber (HNBR)/Polyamide 12 (PA12) blends prepared by electron beam irradiation. Electron beam irradiated blends are characterized by processing behaviour like thermoplastic at elevated temperature and performance properties of vulcanized rubber at ambient temperature. In the present work, a new class of blends based on Hydrogenated acrylonitrile butadiene rubber (HNBR) and polyamide (PA12) has been developed. The blends are cured with different radiation dosage at a fixed blend ratio (70:30) of (HNBR/PA12). The blend having the 75 kGy shows the highest level of mechanical properties as well as superior thermal stability. Dynamic mechanical analysis (DMA) also demonstrates the tanδ values of all the blends are lower and the storage modules are higher for HE-75 kGy blend system compared to other blend system. Heat aging, oil aging, oil swelling and cross-link density study have also been carried out in details to understand the performance behaviour of these blends at service condition (150 °C). These blends are considered to find potential application in automotive sector especially for automotive under-the-hood-applications.

SETI via Leakage from Light Sails in Exoplanetary Systems

NASA Astrophysics Data System (ADS)

Guillochon, James; Loeb, Abraham

2015-10-01

The primary challenge of rocket propulsion is the burden of needing to accelerate the spacecraft’s own fuel, resulting in only a logarithmic gain in maximum speed as propellant is added to the spacecraft. Light sails offer an attractive alternative in which fuel is not carried by the spacecraft, with acceleration being provided by an external source of light. By artificially illuminating the spacecraft with beamed radiation, speeds are only limited by the area of the sail, heat resistance of its material, and power use of the accelerating apparatus. In this paper, we show that leakage from a light sail propulsion apparatus in operation around a solar system analogue would be detectable. To demonstrate this, we model the launch and arrival of a microwave beam-driven light sail constructed for transit between planets in orbit around a single star, and find an optimal beam frequency on the order of tens of GHz. Leakage from these beams yields transients with flux densities of Jy and durations of tens of seconds at 100 pc. Because most travel within a planetary system would be conducted between the habitable worlds within that system, multiply transiting exoplanetary systems offer the greatest chance of detection, especially when the planets are in projected conjunction as viewed from Earth. If interplanetary travel via beam-driven light sails is commonly employed in our galaxy, this activity could be revealed by radio follow-up of nearby transiting exoplanetary systems. The expected signal properties define a new strategy in the search for extraterrestrial intelligence (SETI).

R&D around a photoneutralizer-based NBI system (Siphore) in view of a DEMO Tokamak steady state fusion reactor

NASA Astrophysics Data System (ADS)

Simonin, A.; Achard, Jocelyn; Achkasov, K.; Bechu, S.; Baudouin, C.; Baulaigue, O.; Blondel, C.; Boeuf, J. P.; Bresteau, D.; Cartry, G.; Chaibi, W.; Drag, C.; de Esch, H. P. L.; Fiorucci, D.; Fubiani, G.; Furno, I.; Futtersack, R.; Garibaldi, P.; Gicquel, A.; Grand, C.; Guittienne, Ph.; Hagelaar, G.; Howling, A.; Jacquier, R.; Kirkpatrick, M. J.; Lemoine, D.; Lepetit, B.; Minea, T.; Odic, E.; Revel, A.; Soliman, B. A.; Teste, P.

2015-11-01

Since the signature of the ITER treaty in 2006, a new research programme targeting the emergence of a new generation of neutral beam (NB) system for the future fusion reactor (DEMO Tokamak) has been underway between several laboratories in Europe. The specifications required to operate a NB system on DEMO are very demanding: the system has to provide plasma heating, current drive and plasma control at a very high level of power (up to 150 MW) and energy (1 or 2 MeV), including high performances in term of wall-plug efficiency (η  >  60%), high availability and reliability. To this aim, a novel NB concept based on the photodetachment of the energetic negative ion beam is under study. The keystone of this new concept is the achievement of a photoneutralizer where a high power photon flux (~3 MW) generated within a Fabry-Perot cavity will overlap, cross and partially photodetach the intense negative ion beam accelerated at high energy (1 or 2 MeV). The aspect ratio of the beam-line (source, accelerator, etc) is specifically designed to maximize the overlap of the photon beam with the ion beam. It is shown that such a photoneutralized based NB system would have the capability to provide several tens of MW of D0 per beam line with a wall-plug efficiency higher than 60%. A feasibility study of the concept has been launched between different laboratories to address the different physics aspects, i.e. negative ion source, plasma modelling, ion accelerator simulation, photoneutralization and high voltage holding under vacuum. The paper describes the present status of the project and the main achievements of the developments in laboratories.

Device and method for imploding a microsphere with a fast liner

DOEpatents

Thode, Lester E.

1981-01-01

A device and method for relativistic electron beam heating of a high-density plasma in a small localized region. A relativistic electron beam generator or accelerator produces a high-voltage electron beam which propagates along a vacuum drift tube and is modulated to initiate electron bunching within the beam. The beam is then directed through a low-density gas chamber which provides isolation between the vacuum modulator and the relativistic electron beam target. The relativistic beam is then applied to a high-density target plasma which typically comprises DT, DD, hydrogen boron or similar thermonuclear gas at a density of 10.sup.17 to 10.sup.20 electrons per cubic centimeter. The target gas is ionized prior to application of the electron beam by means of a laser or other preionization source to form a plasma. Utilizing a relativistic electron beam with an individual particle energy exceeding 3 MeV, classical scattering by relativistic electrons passing through isolation foils is negligible. As a result, relativistic streaming instabilities are initiated within the high-density target plasma causing the relativistic electron beam to efficiently deposit its energy and momentum into a small localized region of the high-density plasma target. Fast liners disposed in the high-density target plasma are explosively or ablatively driven to implosion by a heated annular plasma surrounding the fast liner generated by an annular relativistic electron beam. An azimuthal magnetic field produced by axial current flow in the annular plasma, causes the energy in the heated annular plasma to converge on the fast liner to drive the fast liner to implode a microsphere.

Final cooling for a high-energy high-luminosity lepton collider

NASA Astrophysics Data System (ADS)

Neuffer, D.; Sayed, H.; Acosta, J.; Hart, T.; Summers, D.

2017-07-01

A high-energy muon collider requires a "final cooling" system that reduces transverse emittance by a factor of ~ 10, while allowing the longitudinal emittance to increase. The baseline approach has low-energy transverse cooling within high-field solenoids, with strong longitudinal heating. This approach and its recent simulation are discussed. Alternative approaches, which more explicitly include emittance exchange are also presented. Round-to-flat beam transform, transverse slicing, and longitudinal bunch coalescence are possible components of an alternative approach. Wedge-based emittance exchange could provide much of the required transverse cooling with longitudinal heating. Li-lens and quadrupole focusing systems could also provide much of the required final cooling.

Potential for EMU Fabric Damage by Electron Beam and Molten Metal During Space Welding for the International Space Welding Experiment

NASA Technical Reports Server (NTRS)

Fragomeni, James M.

1998-01-01

As a consequence of preparations concerning the International Space Welding Experiment (ISWE), studies were performed to better understand the effect of molten metal contact and electron beam impingement with various fabrics for space suit applications. The question arose as to what would occur if the electron beam from the Ukrainian Universal Hand Tool (UHT) designed for welding in space were to impinge upon a piece of Nextel AF-62 ceramic cloth designed to withstand temperatures up to 1427 C. The expectation was that the electron beam would lay down a static charge pattern with no damage to the ceramic fabric. The electron beam is capable of spraying the fabric with enough negative charge to repel further electrons from the fabric before significant heating occurs. The static charge pattern would deflect any further charge accumulation except for a small initial amount of leakage to the grounded surface of the welder. However, when studies were made of the effect of the electron beam on the insulating ceramic fabric it was surprisingly found that the electron beam did indeed burn through the ceramic fabric. It was also found that the shorter electron beam standoff distances had longer burnthrough times than did some greater electron beam standoff distances. A possible explanation for the longer burnthrough times for the small electron beam standoff distance would be outgassing of the fabric which caused the electron beam hand-tool to cycle on and off to provide some protection for the cathodes. The electron beam hand tool was observed to cycle off at the short standoff distance of two inches likely due to vapors being outgassed. During the electron beam welding process there is an electron leakage, or current leakage, flow from the fabric. A static charge pattern is initially laid down by the electron beam current flow. The static charge makes up the current leakage flow which initially slightly heats up the fabric. The initially laid down surface charge leaks a small amount of current. The rate at which the current charge leaks from the fabric controls how fast the fabric heats up. As the ceramic fabric is heated it begins to outgass primarily from contamination/impurities atoms or molecules on and below the fabric surface. The contaminant gases ionize to create extra charge carriers and multiply a current of electrons. The emitted gas which ionized in the electron leakage flow promotes further leakage. Thus, the small leakage of charge from the fabric surface is enhanced by outgassing. When the electron beam current makes up the lost current, the incoming electrons heat the fabric and further enhance the outgassing. The additional leakage promotes additional heating up of the ceramic fabric. The electrons bound to the ceramic fabric surface leak off more and more as the surface gets hotter promoting even greater leakage. The additional electrons that result also gain energy in the field and produce further electrons. Eventually the process becomes unstable and accelerates to the point where a hole is burned through the fabric.

Behavior of reinforcement SCC beams under elevated temperatures

NASA Astrophysics Data System (ADS)

Fathi, Hamoon; Farhang, Kianoosh

2015-09-01

This experimental study focuses on the behavior of heated reinforced concrete beams. Four types of concrete mixtures were used for the tested self-compacting concrete beams. A total of 72 reinforced concrete beams and 72 standard cylindrical specimens were tested. The compressive strength under uniaxial loading at 23 °C ranged from 30 to 45 MPa. The specimens were exposed to different temperatures. The test parameters of interest were the compressive strength and the temperature of the specimens. The effect of changes in the parameters was examined so as to control the behavior of the tested concrete and that of the reinforced concrete beam. The results indicated that flexibility and compressive strength of the reinforced concrete beams decreased at higher temperatures. Furthermore, heating beyond 400 °C produced greater variations in the structural behavior of the materials in both the cylindrical samples and the reinforced concrete beams.

Deformation and Heat Transfer on Three Sides Protected Beams under Fire Accident

NASA Astrophysics Data System (ADS)

Imran, M.; Liew, M. S.; Garcia, E. M.; Nasif, M. S.; Yassin, A. Y. M.; Niazi, U. M.

2018-04-01

Fire accidents are common in oil and gas industry. The application of passive fire protection (PFP) is a costly solution. The PFP is applied only on critical structural members to optimise project cost. In some cases, beams cannot be protected from the top flange in order to accommodate for the placement of pipe supports and grating. It is important to understand the thermal and mechanical response of beam under such condition. This paper discusses the response of steel beam under ISO 834 fire protected, unprotected and three sides protected beams. The model validated against an experimental study. The experimental study has shown good agreement with FE model. The study revealed that the beams protected from three sides heat-up faster compare to fully protected beam showing different temperature gradient. However, the affects load carrying capacity are insignificant under ISO 834 fire.

A microbeam slit system for high beam currents

NASA Astrophysics Data System (ADS)

Vallentin, T.; Moser, M.; Eschbaumer, S.; Greubel, C.; Haase, T.; Reichart, P.; Rösch, T.; Dollinger, G.

2015-04-01

A new microbeam slit system for high beam currents of 10 μA was built up to improve the brightness transport of a proton beam with a kinetic energy of up to 25 MeV into the microprobe SNAKE. The new slit system features a position accuracy of less than 1 μm under normal operating conditions and less than 2 μm if the beam is switched on and off. The thermal management with a powerful watercooling and potential-free thermocouple feedback controlled heating cables is optimized for constant slit aperture at thermal power input of up to 250 W. The transparent zone is optimized to 0.7 μm due to the use of tungsten formed to a cylindrical surface with a radius r = 100 mm and mechanically lapped surface to minimize small angle scattering effects and to minimize the number of ions passing the slits with low energy loss. Electrical isolation of the slit tip enables slit current monitoring, e.g. for tandem accelerator feedback control. With the ability to transport up to 10 μA of protons with the new microslit system, the brightness Bexp transported into the microprobe was increased by a factor of 2 compared to low current injection using the old slit system.

Performance of a superconducting magnet system operated in the Super Omega Muon beam line at J-PARC

DOE Office of Scientific and Technical Information (OSTI.GOV)

Makida, Yasuhiro; Ikedo, Yutaka; Ogitsu, Toru

A superconducting magnet system, which is composed of an 8 m long solenoid for transportation and 12 short solenoids for focusing, has been developed for Muon Science Establishment facility of J-PARC. The transport solenoid is composed of a 6 m straight section connected to a 45 degree curved section at each end. Muons of various momenta and of both electric charges are transported through the solenoid inner bore with an effective diameter of 0.3 m, where 2 T magnetic field is induced. There are 12 focusing solenoids with an effective bore diameter of 0.6 m and a length of 0.35more » m arranged on a straight line at suitable intervals. The maximum central field of each focusing solenoid is 0.66 T. All solenoid coils are cooled by GM cryocoolers through their own conductions. The magnet system has been installed into the beam line in the summer of 2012, and its performance has been checked. Beam commissioning has been carried out since October 2012. During beam operation, temperature rise over 6 K in the transport solenoid due to a nuclear heating from the muon production target is observed at beam intensity of about 300 kW.« less

Real-time monitoring of thermal and mechanical tissue response to modulated phased-array HIFU beams in vivo

NASA Astrophysics Data System (ADS)

Liu, Dalong; Ballard, John R.; Haritonova, Alyona; Choi, Jeungwan; Bischof, John; Ebbini, Emad S.

2012-10-01

An integrated system employing real-time ultrasound thermography and strain imaging in monitoring tissue response to phased-array heating patterns has been developed. The imaging system is implemented on a commercially available scanner (SonixRP) at frame rates > 500 fps with limited frame sizes covering the vicinity of the HIFU focal spot. These frame rates are sufficient to capture tissue motion and deformation even in the vicinity of large arteries. With the high temporal and spatial resolution of our strain imaging system, we are able to capture and separate tissue strains due to natural motion (breathing and pulsation) from HIFU induced strains (thermal and mechanical). We have collected in vivo strain imaging during sub-therapeutic and therapeutic HIFU exposure in swine and rat model. A 3.5-MHz phased array was used to generate sinusoidally-modulated pHIFU beams at different intensity levels and durations near blood vessels of different sizes (e.g. femoral in the swine and rat models). The results show that our approach is capable of characterizing the thermal and mechanical tissue response to sub-therapeutic pHIFU beam. For therapeutic pHIFU beams, the approach is still capable of localizing the therapeutic beam, but the results at the focal spot are complicated by bubble generation.

Performance and heat transfer characteristics of the laser-heated rocket - A future space transportation system

NASA Technical Reports Server (NTRS)

Shoji, J. M.; Larson, V. R.

1976-01-01

The application of advanced liquid-bipropellant rocket engine analysis techniques has been utilized for prediction of the potential delivered performance and the design of thruster wall cooling schemes for laser-heated rocket thrusters. Delivered specific impulse values greater than 1000 lbf-sec/lbm are potentially achievable based on calculations for thrusters designed for 10-kW and 5000-kW laser beam power levels. A thruster wall-cooling technique utilizing a combination of regenerative cooling and a carbon-seeded hydrogen boundary layer is presented. The flowing carbon-seeded hydrogen boundary layer provides radiation absorption of the heat radiated from the high-temperature plasma. Also described is a forced convection thruster wall cooling design for an experimental test thruster.

Neutronics Assessments for a RIA Fragmentation Line Beam Dump Concept

DOE Office of Scientific and Technical Information (OSTI.GOV)

Boles, J L; Reyes, S; Ahle, L E

Heavy ion and radiation transport calculations are in progress for conceptual beam dump designs for the fragmentation line of the proposed Rare Isotope Accelerator (RIA). Using the computer code PHITS, a preliminary design of a motor-driven rotating wheel beam dump and adjacent downstream multipole has been modeled. Selected results of these calculations are given, including neutron and proton flux in the wheel, absorbed dose and displacements per atom in the hub materials, and heating from prompt radiation and from decay heat in the multipole.

Solutions of the heat conduction equation in multilayers for photothermal deflection experiments

NASA Technical Reports Server (NTRS)

Mcgahan, William A.; Cole, K. D.

1992-01-01

Analytical expressions for temperature and laser beam deflection in multilayer medium is derived using Green function techniques. The approach is based on calculation of the normal component of heat fluxes across the boundaries, from which either the beam deflections or the temperature anywhere in space can be found. A general expression for the measured signals for the case of four-quadrant detection is also presented and compared with previous calculations of detector response for finite probe beams.

Joining of materials using laser heating

DOEpatents

Cockeram, Brian V.; Hicks, Trevor G.; Schmid, Glenn C.

2003-07-01

A method for diffusion bonding ceramic layers such as boron carbide, zirconium carbide, or silicon carbide uses a defocused laser beam to heat and to join ceramics with the use of a thin metal foil insert. The metal foil preferably is rhenium, molybdenum or titanium. The rapid, intense heating of the ceramic/metal/ceramic sandwiches using the defocused laser beam results in diffusive conversion of the refractory metal foil into the ceramic and in turn creates a strong bond therein.

A shape memory polymer concrete crack closure system activated by electrical current

NASA Astrophysics Data System (ADS)

Teall, Oliver; Pilegis, Martins; Davies, Robert; Sweeney, John; Jefferson, Tony; Lark, Robert; Gardner, Diane

2018-07-01

The presence of cracks has a negative impact on the durability of concrete by providing paths for corrosive materials to the embedded steel reinforcement. Cracks in concrete can be closed using shape memory polymers (SMP) which produce a compressive stress across the crack faces. This stress has been previously found to enhance the load recovery associated with autogenous self-healing. This paper details the experiments undertaken to incorporate SMP tendons containing polyethylene terephthalate (PET) filaments into reinforced and unreinforced 500 × 100 × 100 mm structural concrete beam samples. These tendons are activated via an electrical supply using a nickel-chrome resistance wire heating system. The set-up, methodology and results of restrained shrinkage stress and crack closure experiments are explained. Crack closure of up to 85% in unreinforced beams and 26%–39% in reinforced beams is measured using crack-mouth opening displacement, microscope and digital image correlation equipment. Conclusions are made as to the effectiveness of the system and its potential for application within industry.

BPM Button Optimization to Minimize Distortion Due to Trapped Mode Heating

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cameron,P.; Blednyk, A.; Kosciuk, B.

2009-05-04

The outer circumference of a BPM button and the inner circumference of the button housing comprise a transmission line. This transmission line typically presents an impedance of a few tens of ohms to the beam, and couples very weakly to the 50 ohm coaxial transmission line that comprises the signal path out of the button. The modes which are consequently excited and trapped often have quality factors of several hundred, permitting resonant excitation by the beam. The thermal distortion resulting from trapped mode heating is potentially problematic for achieving the high precision beam position measurements needed to provide the sub-micronmore » beam position stability required by light source users. We present a button design that has been optimized via material selection and component geometry to minimize both the trapped mode heating and the resulting thermal distortion.« less

Tailored laser beam shaping for efficient and accurate microstructuring

NASA Astrophysics Data System (ADS)

Häfner, T.; Strauß, J.; Roider, C.; Heberle, J.; Schmidt, M.

2018-02-01

Large-area processing with high material removal rates by ultrashort pulsed (USP) lasers is coming into focus by the development of high-power USP laser systems. However, currently the bottleneck for high-rate production is given by slow and inefficient beam manipulation. On the one hand, slow beam deflection with regard to high pulse repetition rates leads to heat accumulation and shielding effects, on the other hand, a conventional focus cannot provide the optimum fluence due to the Gaussian intensity profile. In this paper, we emphasize on two approaches of dynamic laser beam shaping with liquid crystal on silicon spatial light modulation and acousto-optic beam shaping. Advantages and limitations of dynamic laser beam shaping with regard to USP laser material processing and methods for reducing the influence of speckle are discussed. Additionally, the influence of optics induced aberrations on speckle characteristics is evaluated. Laser material processing results are presented correlating the achieved structure quality with the simulated and measured beam quality. Experimental and analytical investigations show a certain fluence dependence of the necessary number of alternative holograms to realize homogeneous microstructures.

Apparatuses and methods for laser reading of thermoluminescent phosphors

DOEpatents

Braunlich, Peter F.; Tetzlaff, Wolfgang

1989-01-01

Apparatuses and methods for rapidly reading thermoluminescent phosphors to determine the amount of luminescent energy stored therein. The stored luminescent energy is interpreted as a measure of the total exposure of the thermoluminescent phosphor to ionizing radiation. The thermoluminescent phosphor reading apparatus uses a laser to generate a laser beam. The laser beam power level is monitored by a laser power detector and controlled to maintain the power level at a desired value or values which can vary with time. A shutter or other laser beam interrupting means is used to control exposure of the thermoluminescent phosphor to the laser beam. The laser beam can be equalized using an opitcal equalizer so that the laser beam has an approximately uniform power density across the beam. The heated thermoluminescent phosphor emits a visible or otherwise detectable luminescent emission which is measured as an indication of the radiation exposure of the thermoluminscent phosphors. Also disclosed are preferred signal processing and control circuits including one system using a digital computer. Also disclosed are time-profiled laser power cycles for pre-anneal, read and post-anneal treatment of phosphors.

Core cooling under accident conditions at the high-flux beam reactor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tichler, P.; Cheng, L.; Fauske, H.

The High-Flux Beam Reactor (HFBR) at Brookhaven National Laboratory (BNL) is cooled and moderated by heavy water and contains {sup 235}U in the form of narrow-channel, parallel-plate-type fuel elements. During normal operation, the flow direction is downward through the core. This flow direction is maintained at a reduced flow rate during routine shutdown and on loss of commercial power by means of redundant pumps and power supplies. However, in certain accident scenarios, e.g. loss-of-coolant accidents (LOCAs), all forced-flow cooling is lost. Although there was experimental evidence during the reactor design period (1958-1963) that the heat removal capacity in the fullymore » developed natural circulation cooling mode was relatively high, it was not possible to make a confident prediction of the heat removal capacity during the transition from downflow to natural circulation. Accordingly, a test program was initiated using an electrically heated section to simulate the fuel channel and a cooling loop to simulate the balance of the primary cooling system.« less

Feasibility of in situ controlled heat treatment (ISHT) of Inconel 718 during electron beam melting additive manufacturing

DOE PAGES

Sames, William J.; Unocic, Kinga A.; Helmreich, Grant W.; ...

2016-10-07

A novel technique was developed to control the microstructure evolution in Alloy 718 processed using Electron Beam Melting (EBM). In situ solution treatment and aging of Alloy 718 was performed by heating the top surface of the build after build completion scanning an electron beam to act as a planar heat source during the cool down process. Results demonstrate that the measured hardness (478 ± 7 HV) of the material processed using in situ heat treatment similar to that of peak-aged Inconel 718. Large solidification grains and cracks formed, which are identified as the likely mechanism leading to failure ofmore » tensile tests of the in situ heat treatment material under loading. Despite poor tensile performance, the technique proposed was shown to successively age Alloy 718 (increase precipitate size and hardness) without removing the sample from the process chamber, which can reduce the number of process steps in producing a part. Lastly, tighter controls on processing temperature during layer melting to lower process temperature and selective heating during in situ heat treatment to reduce over-sintering are proposed as methods for improving the process.« less

Hydrodynamic and shock heating instabilities of liquid metal strippers for RIA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hassanein, Ahmed

2013-05-24

Stripping of accelerated ions is a key problem for the design of RIA to obtain high efficiency. Thin liquid Lithium film flow is currently considered as stripper for RIA ion beams to obtain higher Z for following acceleration: in extreme case of Uranium from Z=29 to Z=60-70 (first stripper) and from Z=70 till full stripping Z=92 (second stripper). Ionization of ion occurs due to the interaction of the ion with electrons of target material (Lithium) with the loss of parts of the energy due to ionization, Q{sub U}, which is also accompanied with ionization energy losses, Q{sub Li} of themore » lithium. The resulting heat is so high that can be removed not by heat conduction but mainly by convection, i.e., flowing of liquid metal across beam spot area. The interaction of the beam with the liquid metal generates shock wave propagating along direction perpendicular to the beam as well as excites oscillations along beam direction. We studied the dynamics of these excited waves to determine conditions for film stability at the required velocities for heat removal. It will allow optimizing jet nozzle shapes and flow parameters to prevent film fragmentation and to ensure stable device operation.« less

Prestressing effect of cold-drawn short NiTi SMA fibres in steel reinforced mortar beams

NASA Astrophysics Data System (ADS)

Choi, Eunsoo; Kim, Dong Joo; Hwang, Jin-Ha; Kim, Woo Jin

2016-08-01

This study investigated the prestressing effect of cold-drawn short NiTi shape memory alloy (SMA) fibres in steel reinforced mortar beams. The SMA fibres were mixed with 1.5% volume content in a mortar matrix with the compressive strength of 50 MPa. The SMA fibres had an average length of 34 mm, and they were manufactured with a dog-bone shape: the diameters of the end- and middle-parts were 1.024 and 1.0 mm, respectively. Twenty mortar beams with the dimensions of 40 mm × 40 mm × 160 mm (B × H × L) were prepared. Two types of tests were conducted. One was to investigate the prestressing effect of the SMA fibres, and the beams with the SMA fibres were heated at the bottom. The other was to assess the bending behaviour of the beams prestressed by the SMA fibres. The SMA fibres induced upward deflection and cracking at the top surface by heating at the bottom; thus, they achieved an obvious prestressing effect. The beams that were prestressed by the SMA fibres did not show a significant difference in bending behaviour from that of the SMA fibre reinforced beams that were not subjected to heating. Stress analysis of the beams indicated that the prestressing effect decreased in relation to the cooling temperature.

Ion beam development for the needs of the JYFL nuclear physics programme.

PubMed

Koivisto, H; Suominen, P; Ropponen, T; Ropponen, J; Koponen, T; Savonen, M; Toivanen, V; Wu, X; Machicoane, G; Stetson, J; Zavodszky, P; Doleans, M; Spädtke, P; Vondrasek, R; Tarvainen, O

2008-02-01

The increased requirements towards the use of higher ion beam intensities motivated us to initiate the project to improve the overall transmission of the K130 cyclotron facility. With the facility the transport efficiency decreases rapidly as a function of total beam intensity extracted from the JYFL ECR ion sources. According to statistics, the total transmission efficiency is of the order of 10% for low beam intensities (I(total)< or =0.7 mA) and only about 2% for high beam intensities (I(total)>1.5 mA). Requirements towards the use of new metal ion beams for the nuclear physics experiments have also increased. The miniature oven used for the production of metal ion beams at the JYFL is not able to reach the temperature needed for the requested metal ion beams. In order to fulfill these requirements intensive development work has been performed. An inductively and a resistively heated oven has successfully been developed and both are capable of reaching temperatures of about 2000 degrees C. In addition, sputtering technique has been tested. GEANT4 simulations have been started in order to better understand the processes involved with the bremsstrahlung, which gives an extra heat load to cryostat in the case of superconducting ECR ion source. Parallel with this work, a new advanced ECR heating simulation program has been developed. In this article we present the latest results of the above-mentioned projects.

Manipulating Energetic Ion Velocity Space to Control Instabilities and Improve Tokamak Performance

NASA Astrophysics Data System (ADS)

Pace, David C.

2017-10-01

The first-ever demonstration of independent current (I) and voltage (V) control of high power neutral beams in tokamak plasma shots has successfully reduced the prevalence of instabilities and improved energetic ion confinement in experiments at the DIII-D tokamak. Energetic ions drive Alfvén eigenmode (AE) instabilities through a resonant energy exchange that can increase radial diffusion of the ions, thereby reducing beam heating and current drive efficiency. This resonance is incredibly sensitive to the ion velocity and orbit topology, which then allows changes in beam voltage (keeping the injected power constant through compensating changes in current) to remove nearly all instability drive. The implementation of temporal control of beam current and voltage allows for a reduction in the resonant energetic ion velocity space while maintaining the ability to inject maximum power. DIII-D low confinement (L-mode) plasmas demonstrate a nearly complete avoidance of AE activity in plasmas with 55 kV beam injection compared to the many AEs that are observed in plasmas featuring similar total beam power at 70 kV. Across the experimental range of beam settings, resulting increases in beam divergence have been inconsequential. High performance steady-state scenarios featuring equilibria that are conducive to dense arrays of Alfvén waves benefit the most from instability control mechanisms. One such scenario, the so-called high qmin scenario, demonstrates improved confinement and equilibrium evolution when the injected beam voltage begins at lower values (i.e., fewer resonances) and then increases as the plasma reaches its stationary period. These results suggest a future in which plasma confinement and performance is improved through continuous feedback control of auxiliary heating systems such that the energetic ion distribution is constantly adapted to produce an optimal plasma state. Work supported by US DOE under DE-FC02-04ER54698.

Heavy Ion Fusion Science Virtual National Laboratory 4th Quarter 2009 Milestone Report: Measure and simulate target temperature and dynamic response in optimized NDCX-I configurations with initial diagnostics suite

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bieniosek, F.M.; Barnard, J.J.; Henestroza, E.

2009-09-30

This milestone has been met. The effort contains two main components: (1) Experimental results of warm dense matter target experiments on optimized NDCX-I configurations that include measurements of target temperature and transient target behavior. (2) A theoretical model of the target response to beam heating that includes an equilibrium heating model of the target foil and a model for droplet formation in the target for comparison with experimental results. The experiments on ion-beam target heating use a 300-350-keV K{sup +} pulsed beam from the Neutralized Compression Drift Experiment (NDCX-I) accelerator at LBNL. The NDCX-I accelerator delivers an uncompressed pulse beammore » of several microseconds with a typical power density of >100 kW/cm{sup 2} over a final focus spot size of about 1 mm. An induction bunching module the NDCX-I compresses a portion of the beam pulse to reach a much higher power density over 2 nanoseconds. Under these conditions the free-standing foil targets are rapidly heated to temperatures to over 4000 K. We model the target thermal dynamics using the equation of heat conduction for the temperature T(x,t) as a function of time (t) and spatial dimension along the beam direction (x). The competing cooling processes release energy from the surface of the foil due to evaporation, radiation, and thermionic (Richardson) emission. A description of the experimental configuration of the target chamber and results from initial beam-target experiments are reported in our FY08 4th Quarter and FY09 2nd Quarter Milestone Reports. The WDM target diagnostics include a high-speed multichannel optical pyrometer, optical streak camera, VISAR, and high-speed gated cameras. The fast optical pyrometer is a unique and significant new diagnostic which provides valuable information on the temperature evolution of the heated target.« less

Low-energy nuclear reactions in crystal structures

NASA Astrophysics Data System (ADS)

Bagulya, A. V.; Dalkarov, O. D.; Negodaev, M. A.; Rusetskii, A. S.

2017-09-01

Results of studying low-energy nuclear reactions at the HELIS facility (LPI) are presented. Investigations of yields from DD reactions in deuterated crystal structures at deuteron energies of 10 to 25 keV show a considerable enhancement effect. It is shown that exposure of the deuterated targets to the H+ (proton) and Ne+ beams with energies from 10 to 25 keV and an X-ray beam with the energy of 20 to 30 keV stimulates DD reaction yields. For the CVD diamond target, it is shown that its orientation with respect to the deuteron beam affects the neutron yield. The D+ beam is shown to cause much higher heat release in the TiDx target than the H+ and Ne+ beams, and this heat release depends on the deuterium concentration in the target and the current density of the deuteron beam.

Spatial and Temporal Controlled Tissue Heating on a Modified Clinical Ultrasound Scanner for Generating Mild Hyperthermia in Tumors

PubMed Central

Kruse, Dustin E.; Lai, Chun-Yen; Stephens, Douglas N.; Sutcliffe, Patrick; Paoli, Eric E.; Barnes, Stephen H.; Ferrara, Katherine W.

2009-01-01

A new system is presented for generating controlled tissue heating with a clinical ultrasound scanner, and initial in vitro and in vivo results are presented that demonstrate both transient and sustained heating in the mild-hyperthermia range of 37–42ºC. The system consists of a Siemens Antares™ ultrasound scanner, a custom dual-frequency 3-row transducer array and an external temperature feedback control system. The transducer has 2 outer rows that operate at 1.5 MHz for tissue heating and a center row that operates at 5 MHz for B-mode imaging to guide the therapy. We compare the field maps obtained using a hydrophone against calculations of the ultrasound beam based on monochromatic and linear assumptions. Using the finite-difference time-domain (FDTD) method, we compare predicted time-dependent thermal profiles to measured profiles for soy tofu as a tissue-mimicking phantom. In vitro results show differential heating of 6ºC for chicken breast and tofu. In vivo tests of the system were performed on three mice bearing Met-1 tumors, which is a model of aggressive, metastatic and highly vascular breast cancer. In superficially implanted tumors, we demonstrate controlled heating to 42ºC. We show that the system is able to maintain the temperature to within 0.1ºC of the desired temperature both in vitro and in vivo. PMID:20064754

Compact antenna for two-dimensional beam scan in the JT-60U electron cyclotron heating/current drive system

NASA Astrophysics Data System (ADS)

Moriyama, S.; Kajiwara, K.; Takahashi, K.; Kasugai, A.; Seki, M.; Ikeda, Y.; Fujii, T.

2005-11-01

A compact antenna system was designed and fabricated to enable millimeter-wave beam scanning in the toroidal and poloidal directions of the JT-60U tokamak for electron cyclotron heating (ECH) and electron cyclotron current drive (ECCD) experiments. The antenna consists of a fast movable flat mirror mounted on the tokamak vacuum vessel and a rotary focusing mirror attached at the end of the waveguide that is supported from outside the vacuum vessel. This separate support concept enables a compact structure inside a shallow port (0.68×0.54×0.2m) that is shared with a subport for an independent diagnostic system. During a plasma shot, the flat mirror is driven by a servomotor with a 3-m-long drive shaft to reduce the influence of the high magnetic field on the motor. The focusing mirror is rotated by a simple mechanism utilizing a push rod and an air cylinder. The antenna has been operated reliably for 3 years after a small improvement to the rotary drive mechanism. It has made significant contributions to ECH and ECCD experiments, especially the current profile control in JT-60U.

Development of target ion source systems for radioactive beams at GANIL

NASA Astrophysics Data System (ADS)

Bajeat, O.; Delahaye, P.; Couratin, C.; Dubois, M.; Franberg-Delahaye, H.; Henares, J. L.; Huguet, Y.; Jardin, P.; Lecesne, N.; Lecomte, P.; Leroy, R.; Maunoury, L.; Osmond, B.; Sjodin, M.

2013-12-01

The GANIL facility (Caen, France) is dedicated to the acceleration of heavy ion beams including radioactive beams produced by the Isotope Separation On-Line (ISOL) method at the SPIRAL1 facility. To extend the range of radioactive ion beams available at GANIL, using the ISOL method two projects are underway: SPIRAL1 upgrade and the construction of SPIRAL2. For SPIRAL1, a new target ion source system (TISS) using the VADIS FEBIAD ion source coupled to the SPIRAL1 carbon target will be tested on-line by the end of 2013 and installed in the cave of SPIRAL1 for operation in 2015. The SPIRAL2 project is under construction and is being design for using different production methods as fission, fusion or spallation reactions to cover a large area of the chart of nuclei. It will produce among others neutron rich beams obtained by the fission of uranium induced by fast neutrons. The production target made from uranium carbide and heated at 2000 °C will be associated with several types of ion sources. Developments currently in progress at GANIL for each of these projects are presented.

A Spectroscopic Study of Impurity Behavior in Neutral-beam and Ohmically Heated TFTR Discharges

DOE R&D Accomplishments Database

Stratton, B. C.; Ramsey, A. T.; Boody, F. P.; Bush, C. E.; Fonck, R. J.; Groenbner, R. J.; Hulse, R. A.; Richards, R. K.; Schivell, J.

1987-02-01

Quantitative spectroscopic measurements of Z{sub eff}, impurity densities, and radiated power losses have been made for ohmic- and neutral-beam-heated TFTR discharges at a plasma current of 2.2 MA and toroidal field of 4.7 T. Variations in these quantities with line-average plasma density (anti n{sub e}) and beam power up to 5.6 MW are presented for discharges on a graphite movable limiter. A detailed discussion of the use of an impurity transport model to infer absolute impurity densities and radiative losses from line intensity and visible continuum measurements is given. These discharges were dominated by low-Z impurities with carbon having a considerably higher density than oxygen, except in high-anti n{sub e} ohmic discharges, where the densities of carbon and oxygen were comparable. Metallic impurity concentrations and radiative losses were small, resulting in hollow radiated power profiles and fractions of the input power radiated being 30 to 50% for ohmic heating and 30% or less with beam heating. Spectroscopic estimates of the radiated power were in good agreement with bolometrically measured values. Due to an increase in the carbon density, Z{sub eff} rose from 2.0 to 2.8 as the beam power increased from 0 to 5.6 MW, pointing to a potentially serious dilution of the neutron-producing plasma ions as the beam power increased. Both the low-Z and metallic impurity concentrations were approximately constant with minor radius, indicating no central impurity accumulation in these discharges.

MO-F-CAMPUS-J-04: Radiation Heat Load On the MR System of the Elekta Atlantic System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Towe, S; Roberts, D; Overweg, J

2015-06-15

Purpose: The Elekta Atlantic system combines a digital linear accelerator system with a 1.5T Philips MRI machine.This study aimed to assess the energy deposited within the cryostat system when the radiation beam passes through the cryostat. The cryocooler on the magnet has a cooling capacity which is about 1 Watt in excess of the cryogenic heat leak into the magnet’s cold mass. A pressure-controlled heater inside the magnet balances the excess refrigeration power such that the helium pressure in the tank is kept slightly above ambient air pressure. If radiation power is deposited in the cold mass then this heatermore » will need less power to maintain pressure equilibrium and if the radiation heat load exceeds the excess cryocooler capacity the pressure will rise. Methods: An in-house CAD based Monte Carlo code based on Penelope was used to model the entire MR-Linac system to quantify the heat load on the magnet’s cold mass. These results were then compared to experimental results obtained from an Elekta Atlantic system installed in UMC-Utrecht. Results: For a field size of 25 cm x 22 cm and a dose rate of 107 mu.min-1, the energy deposited by the radiation beam led to a reduction in heater power from 1.16 to 0.73 W. Simulations predicted a reduction to 0.69 W which is in good agreement. For the worst case field size (largest) and maximum dose rate the cryostat cooler capacity was exceeded. This resulted in a pressure rise within the system but was such that continuous irradiation for over 12 hours would be required before the magnet would start blowing off helium. Conclusion: The study concluded that the Atlantic system does not have to be duty cycle restricted, even for the worst case non-clinical scenario and that there are no adverse effects on the MR system. Stephen Towe and David Roberts Both work for Elekta; Ezra Van Lanen works for Philips Healthcare; Johan Overweg works for Philips Innovative Technologies.« less

Long pulse operation of the Kamaboko negative ion source on the MANTIS test bed

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tramham, R.; Jacquot, C.; Riz, D.

1998-08-20

Advanced Tokamak concepts and steady state plasma scenarios require external plasma heating and current drive for extended time periods. This poses several problems for the neutral beam injection systems that are currently in use. The power loading of the ion source and accelerator are especially problematic. The Kamaboko negative ion source, a small scale model of the ITER arc source, is being prepared for extended operation of deuterium beams for up to 1000 seconds. The operating conditions of the plasma grid prove to be important for reducing electron power loading of the accelerator. Operation of deuterium beams for extended periodsmore » also poses radiation safety risks which must be addressed.« less

Modeling of a reinforced concrete beam using shape memory alloy as reinforcement bars

NASA Astrophysics Data System (ADS)

Bajoria, Kamal M.; Kaduskar, Shreya S.

2017-04-01

In this paper the structural behavior of reinforced concrete (RC) beams with smart rebars under three point loading system has been numerically studied, using Finite Element Method. The material used in this study is Superelastic Shape Memory Alloy (SE SMA) which contains nickel and titanium. Shape memory alloys (SMAs) are a unique class of materials which have ability to undergo large deformation and also regain their un-deformed shape by removal of stress or by heating. In this study, a uniaxial SMA model is able to reproduce the pseudo-elastic behavior for the reinforcing SMA wires. Finite element simulation is developed in order to study the load-deflection behavior of smart concrete beams subjected to three-point bending tests.

In-Process Thermal Imaging of the Electron Beam Freeform Fabrication Process

NASA Technical Reports Server (NTRS)

Taminger, Karen M.; Domack, Christopher S.; Zalameda, Joseph N.; Taminger, Brian L.; Hafley, Robert A.; Burke, Eric R.

2016-01-01

Researchers at NASA Langley Research Center have been developing the Electron Beam Freeform Fabrication (EBF3) metal additive manufacturing process for the past 15 years. In this process, an electron beam is used as a heat source to create a small molten pool on a substrate into which wire is fed. The electron beam and wire feed assembly are translated with respect to the substrate to follow a predetermined tool path. This process is repeated in a layer-wise fashion to fabricate metal structural components. In-process imaging has been integrated into the EBF3 system using a near-infrared (NIR) camera. The images are processed to provide thermal and spatial measurements that have been incorporated into a closed-loop control system to maintain consistent thermal conditions throughout the build. Other information in the thermal images is being used to assess quality in real time by detecting flaws in prior layers of the deposit. NIR camera incorporation into the system has improved the consistency of the deposited material and provides the potential for real-time flaw detection which, ultimately, could lead to the manufacture of better, more reliable components using this additive manufacturing process.

Sound control by temperature gradients

NASA Astrophysics Data System (ADS)

Sánchez-Dehesa, José; Angelov, Mitko I.; Cervera, Francisco; Cai, Liang-Wu

2009-11-01

This work reports experiments showing that airborne sound propagation can be controlled by temperature gradients. A system of two heated tubes is here used to demonstrate the collimation and focusing of an ultrasonic beam by the refractive index profile created by the temperature gradients existing around the tubes. Numerical simulations supporting the experimental findings are also reported.

Glass Forming Ability in the Equilibrium Immiscible Ag-Ta System Studied by Molecular Dynamics Simulation and Ion Beam Mixing

NASA Astrophysics Data System (ADS)

Zhao, Man; Dai, Xiaodong; Shen, Yixiong; Liu, Baixin

2008-07-01

For the equilibrium immiscible Ag-Ta system characterized by a positive heat of formation of +23 kJ/mol, a proved realistic extended Finnis-Sinclair potential is applied to study the crystal-to-amorphous transition through molecular dynamics simulations and a glass-forming range (GFR) of the Ag-Ta system is determined to be from 10 to 80 at. % of Ta, within which a disordered state is energetically favored than its crystalline counterpart of solid solution. In experiment, the uniform amorphous phases are indeed obtained, by ion beam mixing of far-from-equilibrium, in the Ag38Ta62, Ag30Ta70 and Ag20Ta80 Ag-Ta multilayered films, which fall within the GFR and thus confirm the relevance of the calculated GFR of the system.

Initial operation of high power ICRF system for long pulse in EAST

DOE Office of Scientific and Technical Information (OSTI.GOV)

Qin, C. M., E-mail: chmq@ipp.ac.cn; Zhao, Y. P.; Zhang, X. J.

2015-12-10

The ICRF heating system on EAST upgraded by active cooling aims for long pulse operation. In this paper, the main technical features of the ICRF system are described. One of a major challenges for long pulse operation is RF-edge interactions induced impurity production and heat loading. In EAST, ICRF antenna protections and Faraday screen bars damaged due to LH electron beam are found. Preliminary results for the analysis of the interaction between LHCD and ICRF antenna are discussed. Increase of metal impurities in the plasma during RF pulse and in a larger core radiation are also shown. These RF-edge interactionsmore » at EAST and some preliminary results for the optimizing RF performance will be presented.« less

Design of indirectly heated thoriated tungsten cathode based strip electron gun

DOE Office of Scientific and Technical Information (OSTI.GOV)

Maiti, Namita; Thakur, K.B.; Patil, D.S.

Design of indirectly heated solid cathode based electron gun (200 kW, 45 kV, 270 degree bent strip type electron gun) has been presented. The solid cathode is made of thoriated tungsten. The solid cathode design has been suitably done to achieve required electron beam cross section. The design approach consists of simulation followed by extensive experimentation. In the design, the effort has been put to reduce the non-uniformity of the heat flux from the filament to the solid cathode to obtain better uniformity of temperature on the solid cathode. Trial beam experiments shows that the modified design achieves one tomore » one correspondence of the solid cathode length and the electron beam length. (author)« less

Artificial ion beam instabilities. I - Linear theory. II - Simulations

NASA Astrophysics Data System (ADS)

Scales, W. A.; Kintner, P. M.

1990-07-01

Some of the important plasma instabilities that result when an artificial ion beam is injected into the ionospheric F region are studied using linear Vlasov theory. The variation in wave spectra at the receiver as the receiver and plasma gun separate perpendicularly to the magnetic field is consistent with a beam density decrease at or near the receiver. At separation distances that are large fractions of the beam gyrodiameter, usually narrow-band waves near the background lower hybrid and H+ gyroharmonic frequencies are measured. These observations are consistent with waves expected to be generated by beam densities on the order of or less than a few percent of the background density. At smaller separation distances, broadband waves are usually observed with frequencies from zero up to and above the lower hybrid frequency. Electrostatic particle simulation studies of the plasma instabilities indicate that the broadband fluidlike lower hybrid instability is the most important for background particle heating. Perpendicular H+ heating is more efficient than perpendicular O+ or parallel electron heating for the drift velocity regime most relevant to past experiments.

Recent Upgrades and Extensions of the ASDEX Upgrade ECRH System

NASA Astrophysics Data System (ADS)

Wagner, Dietmar; Stober, Jörg; Leuterer, Fritz; Monaco, Francesco; Münich, Max; Schmid-Lorch, Dominik; Schütz, Harald; Zohm, Hartmut; Thumm, Manfred; Scherer, Theo; Meier, Andreas; Gantenbein, Gerd; Flamm, Jens; Kasparek, Walter; Höhnle, Hendrik; Lechte, Carsten; Litvak, Alexander G.; Denisov, Gregory G.; Chirkov, Alexey; Popov, Leonid G.; Nichiporenko, Vadim O.; Myasnikov, Vadim E.; Tai, Evgeny M.; Solyanova, Elena A.; Malygin, Sergey A.

2011-03-01

The multi-frequency Electron Cyclotron Heating (ECRH) system at the ASDEX Upgrade tokamak employs depressed collector gyrotrons, step-tunable in the range 105-140 GHz. The system is equipped with a fast steerable launcher allowing for remote steering of the ECRH RF beam during the plasma discharge. The gyrotrons and the mirrors are fully integrated in the discharge control system. The polarization can be controlled in a feed-forward mode. 3 Sniffer probes for millimeter wave stray radiation detection have been installed.

A short response time atomic source for trapped ion experiments

NASA Astrophysics Data System (ADS)

Ballance, T. G.; Goodwin, J. F.; Nichol, B.; Stephenson, L. J.; Ballance, C. J.; Lucas, D. M.

2018-05-01

Ion traps are often loaded from atomic beams produced by resistively heated ovens. We demonstrate an atomic oven which has been designed for fast control of the atomic flux density and reproducible construction. We study the limiting time constants of the system and, in tests with 40Ca, show that we can reach the desired level of flux in 12 s, with no overshoot. Our results indicate that it may be possible to achieve an even faster response by applying an appropriate one-off heat treatment to the oven before it is used.

Observation of alpha particle loss from JET plasmas during ion cyclotron resonance frequency heating using a thin foil Faraday cup detector array.

PubMed

Darrow, D S; Cecil, F E; Kiptily, V; Fullard, K; Horton, A; Murari, A

2010-10-01

The loss of MeV alpha particles from JET plasmas has been measured with a set of thin foil Faraday cup detectors during third harmonic heating of helium neutral beam ions. Tail temperatures of ∼ 2 MeV have been observed, with radial scrape off lengths of a few centimeters. Operational experience from this system indicates that such detectors are potentially feasible for future large tokamaks, but careful attention to screening rf and MHD induced noise is essential.

Device and method for electron beam heating of a high density plasma

DOEpatents

Thode, Lester E.

1981-01-01

A device and method for relativistic electron beam heating of a high density plasma in a small localized region. A relativistic electron beam generator produces a high voltage electron beam which propagates along a vacuum drift tube and is modulated to initiate electron bunching within the beam. The beam is then directed through a low density gas chamber which provides isolation between the vacuum modulator and the relativistic electron beam target. The relativistic beam is then applied to a high density target plasma which typically comprises DT, DD, hydrogen boron or similar thermonuclear gas at a density of 10.sup.17 to 10.sup.20 electrons per cubic centimeter. The target plasma is ionized prior to application of the electron beam by means of a laser or other preionization source. Utilizing a relativistic electron beam with an individual particle energy exceeding 3 MeV, classical scattering by relativistic electrons passing through isolation foils is negligible. As a result, relativistic streaming instabilities are initiated within the high density target plasma causing the relativistic electron beam to efficiently deposit its energy into a small localized region within the high density plasma target.

Heating of field-reversed plasma rings estimated with two scaling models

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shearer, J.W.

1978-05-18

Scaling calculations are presented of the one temperature heating of a field-reversed plasma ring. Two sharp-boundary models of the ring are considered: the long thin approximation and a pinch model. Isobaric, adiabatic, and isovolumetric cases are considered, corresponding to various ways of heating the plasma in a real experiment by using neutral beams, or by raising the magnetic field. It is found that the shape of the plasma changes markedly with heating. The least sensitive shape change (as a function of temperature) is found for the isovolumetric heating case, which can be achieved by combining neutral beam heating with compression.more » The complications introduced by this heating problem suggest that it is desirable, if possible, to create a field reversed ring which is already quite hot, rather than cold.« less

White Beam Slits and Pink Beam Slits for the Hard X-ray Nanoprobe Beamline at the Advanced Photon Source

DOE Office of Scientific and Technical Information (OSTI.GOV)

Benson, C.; Jaski, Y.; Powers, T.

2007-01-19

A new type of slit has been designed for use in the hard x-ray nanoprobe beamline at the Advanced Photon Source (APS). The design incorporates monolithic GlidCop slit bodies mounted to commercially available x-y drive systems. Long, tapered apertures with adjacent water-cooling channels intercept the x-ray beam, removing the high heat load produced by two collinear APS undulators. The apertures are L-shaped and provide both horizontal and vertical slits. The beam-defining edges, positioned at the end of the tapered surfaces, consist of two sets of tungsten blades. These blades produce an exit beam with sharp corners and assure a cleanmore » cut-off for the white beam edges. The slit assembly is designed to allow overlap of the slit edges to stop the beam.The white beam slit design accommodates 3100 W of total power with a peak power density of 763 W/mm2. The pink beam slit design accommodates 400 W of total power with a peak power density of 180 W/mm2. Detailed thermal analyses were performed to verify the slits' accuracy under full beam loading. The new concept allows beamline operations to 180 mA with a simplified design approach.« less

White beam slits and pink beam slits for the hard x-ray nanoprobe beamline at the Advanced Photon Source.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Benson, C.; Jaski, Y.; Maser, J.

2007-01-01

A new type of slit has been designed for use in the hard x-ray nanoprobe beamline at the Advanced Photon Source (APS). The design incorporates monolithic GlidCop slit bodies mounted to commercially available x-y drive systems. Long, tapered apertures with adjacent water-cooling channels intercept the x-ray beam, removing the high heat load produced by two collinear APS undulators. The apertures are L-shaped and provide both horizontal and vertical slits. The beam-defining edges, positioned at the end of the tapered surfaces, consist of two sets of tungsten blades. These blades produce an exit beam with sharp corners and assure a cleanmore » cut-off for the white beam edges. The slit assembly is designed to allow overlap of the slit edges to stop the beam. The white beam slit design accommodates 3100 W of total power with a peak power density of 763 W/mm2. The pink beam slit design accommodates 400 W of total power with a peak power density of 180 W/mm2. Detailed thermal analyses were performed to verify the slits accuracy under full beam loading. The new concept allows beamline operations to 180 mA with a simplified design approach.« less

Flat-top beam for laser-stimulated pain

NASA Astrophysics Data System (ADS)

McCaughey, Ryan; Nadeau, Valerie; Dickinson, Mark

2005-04-01

One of the main problems during laser stimulation in human pain research is the risk of tissue damage caused by excessive heating of the skin. This risk has been reduced by using a laser beam with a flattop (or superGaussian) intensity profile, instead of the conventional Gaussian beam. A finite difference approximation to the heat conduction equation has been applied to model the temperature distribution in skin as a result of irradiation by flattop and Gaussian profile CO2 laser beams. The model predicts that a 15 mm diameter, 15 W, 100 ms CO2 laser pulse with an order 6 superGaussian profile produces a maximum temperature 6 oC less than a Gaussian beam with the same energy density. A superGaussian profile was created by passing a Gaussian beam through a pair of zinc selenide aspheric lenses which refract the more intense central region of the beam towards the less intense periphery. The profiles of the lenses were determined by geometrical optics. In human pain trials the superGaussian beam required more power than the Gaussian beam to reach sensory and pain thresholds.

A simple optical system delivering a tunable micrometer pink beam that can compensate for heat-induced deformations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reininger, Ruben; Liu, Zunping; Doumy, Gilles

2015-06-09

The radiation from an undulator reflected from one or more optical elements (usually termed `pink-beam') is used in photon-hungry experiments. The optical elements serve as a high-energy cutoff and for focusing purposes. One of the issues with this configuration is maintaining the focal spot dimension as the energy of the undulator is varied, since this changes the heat load absorbed by the first optical element. Finite-element analyses of the power absorbed by a side water-cooled mirror exposed to the radiation emitted by an undulator at the Advanced Photon Source (APS) and at the APS after the proposed upgrade (APSU) revealsmore » that the mirror deformation is very close to a convex cylinder creating a virtual source closer to the mirror than the undulator source. Here a simple optical system is described based on a Kirkpatrick–Baez pair which keeps the focus size to less than 2 µm (in the APSU case) with a working distance of 350 mm despite the heat-load-induced change in source distance. Detailed ray tracings at several photon energies for both the APS and APSU show that slightly decreasing the angle of incidence on the mirrors corrects the change in the `virtual' position of the source. The system delivers more than 70% of the first undulator harmonic with very low higher-orders contamination for energies between 5 and 10 keV.« less

Activating neurons by light in free-moving adult flies

NASA Astrophysics Data System (ADS)

Wu, Ming-Chin; Hsiao, Po-Yen; Chu, Li-An; Lin, Yen-Yin; Fu, Chien-Chung; Chiang, Ann-Shyn

2015-01-01

In this presentation, we show our preliminary results which is related to neurons activation in vivo by laser. A laser scanning system was adopted to guide laser beam to an assigned fly and an assigned position. A 473-nm laser can be a heat punishment source to restrain a wild-type fly's moving area. Furthermore, neurons in optogenetics transgene flies can be triggered by the blue laser in this system.

Electron-Optical System of the Gyrotron Designed for Operation in the DNP-NMR Spectrometer Cryomagnet ("Gyrotrino")

NASA Astrophysics Data System (ADS)

Bratman, V. L.; Fedotov, A. E.; Kalynov, Yu. K.; Manuilov, V. N.

2017-08-01

The formation and utilization of a helical electron beam are studied theoretically for a gyrotron with a very low operating voltage in a range 1.5-1.8 kV. Such a gyrotron ("gyrotrino") was earlier proposed for operation inside a magnetic system of an NMR spectrometer with a dynamic nuclear polarization upgrade. Despite the very low voltage, the optimization of the electrode shape can provide velocity and positional electron spreads not exceeding these values for conventional high-voltage gyrotrons. A very small cathode-anode separation makes the gyrotrino very sensitive to thermal expansion of the gun elements that should be compensated by movement of the cathode. Estimations for long-pulse and CW regimes of the gyrotrino operation show that the ion background significantly decreases the reduction of the beam potential and leads to an acceptable drift of the electron cyclotron frequency at the voltage front. A satisfactory thermal load on the waste-beam collector located in a strong uniform magnetic field can be achieved due to the omnidirectional heat flow regime occurring in the case of thin beam footprint.

Mechanisms of material removal and mass transport in focused ion beam nanopore formation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Das, Kallol, E-mail: das7@illinois.edu; Johnson, Harley T., E-mail: htj@illinois.edu; Freund, Jonathan B., E-mail: jbfreund@illinois.edu

2015-02-28

Despite the widespread use of focused ion beam (FIB) processing as a material removal method for applications ranging from electron microscope sample preparation to nanopore processing for DNA sequencing, the basic material removal mechanisms of FIB processing are not well understood. We present the first complete atomistic simulation of high-flux FIB using large-scale parallel molecular dynamics (MD) simulations of nanopore fabrication in freestanding thin films. We focus on the root mechanisms of material removal and rearrangement and describe the role of explosive boiling in forming nanopores. FIB nanopore fabrication is typically understood to occur via sputter erosion. This can bemore » shown to be the case in low flux systems, where individual ion impacts are sufficiently separated in time that they may be considered as independent events. But our detailed MD simulations show that in high flux FIB processing, above a threshold level at which thermal effects become significant, the primary mechanism of material removal changes to a significantly accelerated, thermally dominated process. Under these conditions, the target is heated by the ion beam faster than heat is conducted away by the material, leading quickly to melting, and then continued heating to nearly the material critical temperature. This leads to explosive boiling of the target material with spontaneous bubble formation and coalescence. Mass is rapidly rearranged at the atomistic scale, and material removal occurs orders of magnitude faster than would occur by simple sputtering. While the phenomenology is demonstrated computationally in silicon, it can be expected to occur at lower beam fluxes in other cases where thermal conduction is suppressed due to material properties, geometry, or ambient thermal conditions.« less

Initial benchmarking of a new electron-beam raster pattern generator for 130-100 nm maskmaking

NASA Astrophysics Data System (ADS)

Sauer, Charles A.; Abboud, Frank E.; Babin, Sergey V.; Chakarian, Varoujan; Ghanbari, Abe; Innes, Robert; Trost, David; Raymond, Frederick, III

2000-07-01

The decision by the Semiconductor Industry Association (SIA) to accelerate the continuing evolution to smaller linewidths is consistent with the commitment by Etec Systems, Inc. to rapidly develop new technologies for pattern generation systems with improved resolution, critical dimension (CD) uniformity, positional accuracy, and throughput. Current pattern generation designs are inadequate to meet the more advanced requirements for masks, particularly at or below the 100 nm node. Major changes to all pattern generation tools will be essential to meet future market requirements. An electron-beam (e-beam) system that is designed to meet the challenges for 130 - 100 nm device generation with extendibility to the 70-nm range will be discussed. This system has an architecture that includes a graybeam writing strategy, a new state system, and improved thermal management. Detailed changes include a pulse width modulated blanking system, per-pixel deflection, retrograde scanning multipass writing, and a column with a 50 kV accelerating voltage that supports a dose of up to 45 (mu) C/cm2 with minimal amounts of resist heating. This paper examines current issues, our approach to meeting International Technology Roadmap for Semiconductors (ITRS) requirements, and some preliminary results from a new pattern generator.

Behavior of graphite under heat load and in contact with a hydrogen plasma

NASA Astrophysics Data System (ADS)

Bohdansky, J.; Croessmann, C. D.; Linke, J.; McDonald, J. M.; Morse, D. H.; Pontau, A. E.; Watson, R. D.; Whitley, J. B.; Goebel, D. M.; Hirooka, Y.; Leung, K.; Conn, R. W.; Roth, J.; Ottenberger, W.; Kotzlowski, H. E.

1987-05-01

Graphite is extensively used in large tokamaks today. In these machines the material is exposed to vacuum, to intense heat loads, and to the edge plasma. The use of graphite in such machines, therefore, depends on the outgassing behavior, the heat shock resistance, and thermochemical properties in a hydrogen plasma. Investigations of these properties made at different laboratories are described here. Experiments conducted at Sandia National Laboratories (SNL), Livermore, and the Max-Planck-Institut für Plasmaphysik (IPP) in Garching showed that the outgassing behavior of fine-grain reactor-grade graphite and carbon fiber composites depends on the pretreatment (manufacturing and/or storage). However, after proper outgassing the samples tested behave similarly in the case of fine-grain graphite, but the outgassing remains high for the carbon fiber composites. Heat shock tests have been made with the Electron Beam Test System (EBTS) at SNL, Albuquerque. Directly cooled graphite samples (FE 159 graphite brazed onto Mo tubes) showed no failure at a heat load of 700 W/cm 2, 20 s; or 10 kW, 1 s. Thermal erosion due to sublimination and particle emission from the graphite surface was observed. This effect is related to the surface temperature and becomes significant at temperatures above 2500°K. Fourteen different types of graphite were tested; the main differences among these samples were the different surface temperatures obtained under the same heating conditions. Cracking due to heat shocks was observed in some of the samples, but none of the carbon fiber composites failed. Thermochemical properties have been tested in the PISCES plasma generator at UCLA for ion energies of around 100 eV. The formation of C-H compounds was observed spectroscopically at sample temperatures of around 600°C. However, this chemical reaction did not lead to erosion as observed in beam experiments but to a drastic change of the surface structure due to redeposition. Carbon-hydrogen lines were still observed at sample temperatures of around 100°C. Under these conditions the erosion yield is high and in agreement with those measured in beam experiments.

A first characterization of the NIO1 particle beam by means of a diagnostic calorimeter

NASA Astrophysics Data System (ADS)

Pimazzoni, A.; Cavenago, M.; Cervaro, V.; Fasolo, D.; Serianni, G.; Tollin, M.; Veltri, P.

2017-08-01

Powerful neutral beam injectors (NBI) are required as heating and current drive systems for tokamaks like ITER. The development of negative ion sources and accelerators (40 A; 1 MeV D- beam) in particular, is a crucial point and many issues still require a better understanding. In this framework, the experiment NIO1 (9 beamlets of 15 mA H- each, 60 kV) operated at Consorzio RFX started operation in 2014[1]. Both its RF negative ion source (up to 2.5 kW) and its beamline are equipped with many diagnostics [2]. For the early tests on the extraction system, oxygen has been used as well as hydrogen due to its higher electronegativity, which allows reaching currents large enough to test the beam diagnostics even without caesium injection. In particular a 1D-CFC (carbon-fibre-carbon composite) tile is used as a calorimeter to determine the beam power deposition by observing the rear surface of the tile with an infra-red camera; the same design is applied as for STRIKE [3], one of the diagnostics of SPIDER (the ITER-like ion source prototype [4]) whose facility is currently under construction at Consorzio RFX. From this diagnostic it is also possible to assess the beam divergence and thus the beam optics. The present contribution describes the characterization of the NIO1 particle beam by means of temperature and current measurements with different source and accelerator parameters.

Progress on development of SPIDER diagnostics

NASA Astrophysics Data System (ADS)

Pasqualotto, R.; Agostini, M.; Barbisan, M.; Bernardi, M.; Brombin, M.; Cavazzana, R.; Croci, G.; Palma, M. Dalla; Delogu, R. S.; Gorini, G.; Lotto, L.; Muraro, A.; Peruzzo, S.; Pimazzoni, A.; Pomaro, N.; Rizzolo, A.; Serianni, G.; Spolaore, M.; Tardocchi, M.; Zaniol, B.; Zaupa, M.

2017-08-01

SPIDER experiment, the full size prototype of the beam source for the ITER heating neutral beam injector, has to demonstrate extraction and acceleration to 100 kV of a large negative ion hydrogen or deuterium beam with co-extracted electron fraction e-/D- <1 and beam uniformity within 10%, for up to one hour beam pulses. Main RF source plasma and beam parameters are measured with different complementary techniques to exploit the combination of their specific features. While SPIDER plant systems are being installed, the different diagnostic systems are in the procurement phase. Their final design is described here with a focus on some key solutions and most original and cost effective implementations. Thermocouples used to measure the power load distribution in the source and over the beam dump front surface will be efficiently fixed with proven technique and acquired through commercial and custom electronics. Spectroscopy needs to use well collimated lines of sight and will employ novel design spectrometers with higher efficiency and resolution and filtered detectors with custom built amplifiers. The electrostatic probes will be operated through electronics specifically developed to cope with the challenging environment of the RF source. The instrumented calorimeter STRIKE will use new CFC tiles, still under development. Two linear cameras, one built in house, have been tested as suitable for optical beam tomography. Some diagnostic components are off the shelf, others are custom developed: some of these are being prototyped or are under test before final production and installation, which will be completed before start of SPIDER operation.

Numerical simulation of electron beam welding with beam oscillations

NASA Astrophysics Data System (ADS)

Trushnikov, D. N.; Permyakov, G. L.

2017-02-01

This research examines the process of electron-beam welding in a keyhole mode with the use of beam oscillations. We study the impact of various beam oscillations and their parameters on the shape of the keyhole, the flow of heat and mass transfer processes and weld parameters to develop methodological recommendations. A numerical three-dimensional mathematical model of electron beam welding is presented. The model was developed on the basis of a heat conduction equation and a Navier-Stokes equation taking into account phase transitions at the interface of a solid and liquid phase and thermocapillary convection (Marangoni effect). The shape of the keyhole is determined based on experimental data on the parameters of the secondary signal by using the method of a synchronous accumulation. Calculations of thermal and hydrodynamic processes were carried out based on a computer cluster, using a simulation package COMSOL Multiphysics.

Pressure control of a proton beam-irradiated water target through an internal flow channel-induced thermosyphon.

PubMed

Hong, Bong Hwan; Jung, In Su

2017-07-01

A water target was designed to enhance cooling efficiency using a thermosyphon, which is a system that uses natural convection to induce heat exchange. Two water targets were fabricated: a square target without any flow channel and a target with a flow channel design to induce a thermosyphon mechanism. These two targets had the same internal volume of 8 ml. First, visualization experiments were performed to observe the internal flow by natural convection. Subsequently, an experiment was conducted to compare the cooling performance of both water targets by measuring the temperature and pressure. A 30-MeV proton beam with a beam current of 20 μA was used to irradiate both targets. Consequently, the target with an internal flow channel had a lower mean temperature and a 50% pressure drop compared to the target without a flow channel during proton beam irradiation. Copyright © 2017 Elsevier Ltd. All rights reserved.

DCS - A high flux beamline for time resolved dynamic compression science – Design highlights

DOE PAGES

Capatina, D.; D’Amico, K.; Nudell, J.; ...

2016-07-27

The Dynamic Compression Sector (DCS) beamline, a national user facility for time resolved dynamic compression science supported by the National Nuclear Security Administration (NNSA) of the Department of Energy (DOE), has recently completed construction and is being commissioned at Sector 35 of the Advanced Photon Source (APS) at Argonne National Laboratory (ANL). The beamline consists of a First Optics Enclosure (FOE) and four experimental enclosures. A Kirkpatrick–Baez focusing mirror system with 2.2 mrad incident angles in the FOE delivers pink beam to the experimental stations. A refocusing Kirkpatrick–Baez mirror system is situated in each of the two most downstream enclosures.more » Experiments can be conducted in either white, monochromatic, pink or monochromatic-reflected beam mode in any of the experimental stations by changing the position of two interlocked components in the FOE. The beamline Radiation Safety System (RSS) components have been designed to handle the continuous beam provided by two in-line revolver undulators with periods of 27 and 30 mm, at closed gap, 150 mA beam current, and passing through a power limiting aperture of 1.5 x 1.0 mm 2. A novel pink beam end station stop [1] is used to stop the continuous and focused pink beam which can achieve a peak heat flux of 105 kW/mm 2. Finally, a new millisecond shutter design [2] is used to deliver a quick pulse of beam to the sample, synchronized with the dynamic event, the microsecond shutter, and the storage ring clock.« less

DCS - A high flux beamline for time resolved dynamic compression science – Design highlights

DOE Office of Scientific and Technical Information (OSTI.GOV)

Capatina, D., E-mail: capatina@aps.anl.gov; D’Amico, K., E-mail: kdamico@aps.anl.gov; Nudell, J., E-mail: jnudell@aps.anl.gov

2016-07-27

The Dynamic Compression Sector (DCS) beamline, a national user facility for time resolved dynamic compression science supported by the National Nuclear Security Administration (NNSA) of the Department of Energy (DOE), has recently completed construction and is being commissioned at Sector 35 of the Advanced Photon Source (APS) at Argonne National Laboratory (ANL). The beamline consists of a First Optics Enclosure (FOE) and four experimental enclosures. A Kirkpatrick–Baez focusing mirror system with 2.2 mrad incident angles in the FOE delivers pink beam to the experimental stations. A refocusing Kirkpatrick–Baez mirror system is situated in each of the two most downstream enclosures.more » Experiments can be conducted in either white, monochromatic, pink or monochromatic-reflected beam mode in any of the experimental stations by changing the position of two interlocked components in the FOE. The beamline Radiation Safety System (RSS) components have been designed to handle the continuous beam provided by two in-line revolver undulators with periods of 27 and 30 mm, at closed gap, 150 mA beam current, and passing through a power limiting aperture of 1.5 x 1.0 mm{sup 2}. A novel pink beam end station stop [1] is used to stop the continuous and focused pink beam which can achieve a peak heat flux of 105 kW/mm{sup 2}. A new millisecond shutter design [2] is used to deliver a quick pulse of beam to the sample, synchronized with the dynamic event, the microsecond shutter, and the storage ring clock.« less

DCS - A High Flux Beamline for Time Resolved Dynamic Compression Science – Design Highlights

DOE Office of Scientific and Technical Information (OSTI.GOV)

Capatina, D.; D'Amico, Kevin L.; Nudell, J.

2016-07-27

The Dynamic Compression Sector (DCS) beamline, a national user facility for time resolved dynamic compression science supported by the National Nuclear Security Administration (NNSA) of the Department of Energy (DOE), has recently completed construction and is being commissioned at Sector 35 of the Advanced Photon Source (APS) at Argonne National Laboratory (ANL). The beamline consists of a First Optics Enclosure (FOE) and four experimental enclosures. A Kirkpatrick–Baez focusing mirror system with 2.2 mrad incident angles in the FOE delivers pink beam to the experimental stations. A refocusing Kirkpatrick–Baez mirror system is situated in each of the two most downstream enclosures.more » Experiments can be conducted in either white, monochromatic, pink or monochromatic-reflected beam mode in any of the experimental stations by changing the position of two interlocked components in the FOE. The beamline Radiation Safety System (RSS) components have been designed to handle the continuous beam provided by two in-line revolver undulators with periods of 27 and 30 mm, at closed gap, 150 mA beam current, and passing through a power limiting aperture of 1.5 x 1.0 mm2. A novel pink beam end station stop [1] is used to stop the continuous and focused pink beam which can achieve a peak heat flux of 105 kW/mm2. A new millisecond shutter design [2] is used to deliver a quick pulse of beam to the sample, synchronized with the dynamic event, the microsecond shutter, and the storage ring clock.« less

SETI VIA LEAKAGE FROM LIGHT SAILS IN EXOPLANETARY SYSTEMS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Guillochon, James; Loeb, Abraham, E-mail: jguillochon@cfa.harvard.edu, E-mail: aloeb@cfa.harvard.edu

The primary challenge of rocket propulsion is the burden of needing to accelerate the spacecraft’s own fuel, resulting in only a logarithmic gain in maximum speed as propellant is added to the spacecraft. Light sails offer an attractive alternative in which fuel is not carried by the spacecraft, with acceleration being provided by an external source of light. By artificially illuminating the spacecraft with beamed radiation, speeds are only limited by the area of the sail, heat resistance of its material, and power use of the accelerating apparatus. In this paper, we show that leakage from a light sail propulsionmore » apparatus in operation around a solar system analogue would be detectable. To demonstrate this, we model the launch and arrival of a microwave beam-driven light sail constructed for transit between planets in orbit around a single star, and find an optimal beam frequency on the order of tens of GHz. Leakage from these beams yields transients with flux densities of Jy and durations of tens of seconds at 100 pc. Because most travel within a planetary system would be conducted between the habitable worlds within that system, multiply transiting exoplanetary systems offer the greatest chance of detection, especially when the planets are in projected conjunction as viewed from Earth. If interplanetary travel via beam-driven light sails is commonly employed in our galaxy, this activity could be revealed by radio follow-up of nearby transiting exoplanetary systems. The expected signal properties define a new strategy in the search for extraterrestrial intelligence (SETI)« less

Shot-noise dominant regime of a nanoparticle in a laser beam

NASA Astrophysics Data System (ADS)

Zhong, Changchun; Robicheaux, Francis

2017-04-01

The technique of laser levitation of nanoparticles has become increasingly promising in the study of cooling and controlling mesoscopic quantum systems. Unlike a mechanical system, the levitated nanoparticle is less exposed to thermalization and decoherence due to the absence of direct contact with a thermal environment. In ultrahigh vacuum, the dominant source of decoherence comes from the unavoidable photon recoil from the optical trap which sets an ultimate bound for the control of levitated systems. In this paper, we study the shot noise heating and the parametric feedback cooling of an optically trapped anisotropic nanoparticle in the laser shot noise dominant regime. The rotational trapping frequency and shot noise heating rate have a dependence on the shape of the trapped particle. For an ellipsoidal particle, the ratio of the axis lengths and the overall size controls the shot noise heating rate relative to the rotational frequency. For a near spherical nanoparticle, the effective heating rate for the rotational degrees of freedom is smaller than that for translation suggesting that the librational ground state may be easier to achieve than the vibrational ground state.

Frictional Heating of Ions In The F2-region of The Ionosphere

NASA Astrophysics Data System (ADS)

Zhizhko, G. O.; Vlasov, V. G.

Auroral electron beams unstable on the Cherenkov resonance are stabilized by large- scale inhomogeneity of the plasma density during all their way from the acceleration region to the E-region of the ionosphere. The generation of plasma waves by beam is possible only in the region of small plasma density gradients, that always is the area of the F2-region maximum. Thus, collective dissipation of the electron beam energy occurs in the local region with the length about several tens of kilometers. This leads to the intensive heating of the electrons(up to temperatures about 10000 K) and will give origin to the ion upflows with velocity about 1 km/s and density about 109 cm-2 s-1. These flows can result in the ion frictional heating. At the same time ion temperatures reach the values about 5000 K. A numerical simulation of the ion frictional heating in the presence of collective elec- tron heating in the high-latitude F2-region of the ionosphere was performed. The sim- ulation has shown that the most critical parameter for the occurence of the ion fric- tional heating was the the steepness of the plasma density profile above the F2-region maximum.

Investigation of Laser Parameters in Silicon Pulsed Laser Conduction Welding

NASA Astrophysics Data System (ADS)

Shayganmanesh, Mahdi; Khoshnoud, Afsaneh

2016-03-01

In this paper, laser welding of silicon in conduction mode is investigated numerically. In this study, the effects of laser beam characteristics on the welding have been studied. In order to model the welding process, heat conduction equation is solved numerically and laser beam energy is considered as a boundary condition. Time depended heat conduction equation is used in our calculations to model pulsed laser welding. Thermo-physical and optical properties of the material are considered to be temperature dependent in our calculations. Effects of spatial and temporal laser beam parameters such as laser beam spot size, laser beam quality, laser beam polarization, laser incident angle, laser pulse energy, laser pulse width, pulse repetition frequency and welding speed on the welding characteristics are assessed. The results show that how the temperature dependent thermo-physical and optical parameters of the material are important in laser welding modeling. Also the results show how the parameters of the laser beam influence the welding characteristics.

Combined action of corrugation and Weibel instabilities from electron-beam interaction with laser-irradiated plasma

NASA Astrophysics Data System (ADS)

Bai, Yafeng; Tian, Ye; Zhang, Zhijun; Cao, Lihua; Liu, Jiansheng

2018-03-01

The combined action of corrugation and Weibel instabilities was experimentally observed in the interaction between energetic electrons and a laser-irradiated insulated target. The energetic electron beam, driven by an ultrashort laser pulse, splits into filaments with a diameter of ˜10 μm while traversing an insulated target, owing to the corrugation instability. The filaments continued to split into thinner filaments owing to the Weibel instability if a preplasma was induced by a heating beam on the rear side of the target. When the time delay between the heating beam and electron beam was larger than 1 ps, a merging of the current filaments was observed. The characteristic filamentary structures disappeared when the time delay between the two beams was larger than 3 ps. A simplified model was developed to analyze this process; the obtained results were in good agreement with the experiment. Two-dimensional particle-in-cell simulations supported our analysis and reproduced the filamentation of the electron beam inside the plasma.

Modelling of pulsed electron beam induced graphite ablation: Sublimation versus melting

NASA Astrophysics Data System (ADS)

Ali, Muddassir; Henda, Redhouane

2017-12-01

Pulsed electron beam ablation (PEBA) has recently emerged as a very promising technique for the deposition of thin films with superior properties. Interaction of the pulsed electron beam with the target material is a complex process, which consists of heating, phase transition, and erosion of a small portion from the target surface. Ablation can be significantly affected by the nature of thermal phenomena taking place at the target surface, with subsequent bearing on the properties, stoichiometry and structure of deposited thin films. A two stage, one-dimensional heat conduction model is presented to describe two different thermal phenomena accounting for interaction of a graphite target with a polyenergetic electron beam. In the first instance, the thermal phenomena are comprised of heating, melting and vaporization of the target surface, while in the second instance the thermal phenomena are described in terms of heating and sublimation of the graphite surface. In this work, the electron beam delivers intense electron pulses of ∼100 ns with energies up to 16 keV and an electric current of ∼400 A to a graphite target. The temperature distribution, surface recession velocity, ablated mass per unit area, and ablation depth for the graphite target are numerically simulated by the finite element method for each case. Based on calculation findings and available experimental data, ablation appears to occur mainly in the regime of melting and vaporization from the surface.

Method of beam welding metallic parts together and apparatus for doing same

DOEpatents

Lewandowski, Edward F.; Cassidy, Dale A.; Sommer, Robert G.

1987-01-01

The disclosed method provides for temporarily clamping a metallic piece to one side of a metallic plate while leaving the opposite side of the plate exposed, and providing a heat conductive heat sink body configured to engage the adjacent portions of such one side of the plate and the piece at all regions proximate to but not at the interface between these components. Such exposed side of such plate is then subjected to an electron welding beam, in exact registry with but opposite to the piece. The electron welding beam is supplied with adequate energy for penetrating through the plate, across the interface, and into the piece, whereby the electron welding beam produces molten material from both the plate and the piece in the region of the interface. The molten material flows into any interstices that may exist in the interface, and upon cooling solidifies to provide a welded joint between the plate and piece, where the interface was, virtually without any interstices. The heat sink material prevents the molten material from extruding beyond what was the interface, to provide a clean welded joint. The heat sink body also mechanically holds the plate and piece together prior to the actual welding.

Method of beam welding metallic parts together and apparatus for doing same

DOEpatents

Lewandowski, E.F.; Cassidy, D.A.; Sommer, R.G.

1985-11-29

This method provides for temporarily clamping a metallic piece to one side of a metallic plate while leaving the opposite side of the plate exposed, and providing a heat conductive heat sink body configured to engage the adjacent portions of such one side of the plate and the piece at all regions proximate to but not at the interface between these components. The exposed side of such plate is then subjected to an electron welding beam, in exact registry with but opposite to the piece. The electron welding beam is supplied with adequate energy for penetrating through the plate, across the interface, and into the piece, whereby the electron welding beam produces molten material from both the plate and the piece in the region of the interface. The molten material flows into any interstices that may exist in the interface, and upon cooling solidifies to provide a welded joint between the plate and piece, where the interface was, virtually without any interstices. The heat sink material prevents the molten material from extrucing beyond what was the interface, to provide a clean welded joint. The heat sink body also mechanically holds the plate and piece together prior to the actual welding.

Research and Development on the Storage Ring Vacuum System for the APS Upgrade Project

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stillwell, B.; Brajuskovic, B.; Carter, J.

A number of research and development activities are underway at Argonne National Laboratory to build confidence in the designs for the storage ring vacuum system required for the Advanced Photon Source Up-grade project (APS-U) [1]. The predominant technical risks are: excessive residual gas pressures during operation; insufficient beam position monitor stability; excessive beam impedance; excessive heating by induced electrical surface currents; and insufficient operational reliability. Present efforts to mitigate these risks include: building and evaluating mockup assemblies; performing mechanical testing of chamber weld joints; developing computational tools; investigating design alternatives; and performing electrical bench measurements. Status of these activities andmore » some of what has been learned to date will be shared.« less

APPARATUS FOR ELECTRON BEAM HEATING CONTROL

DOEpatents

Jones, W.H.; Reece, J.B.

1962-09-18

An improved electron beam welding or melting apparatus is designed which utilizes a high voltage rectifier operating below its temperature saturation region to decrease variations in electron beam current which normally result from the gas generated in such apparatus. (AEC)

Effect of Post Weld Heat Treatment on Corrosion Behavior of AA2014 Aluminum – Copper Alloy Electron Beam Welds

NASA Astrophysics Data System (ADS)

Venkata Ramana, V. S. N.; Mohammed, Raffi; Madhusudhan Reddy, G.; Srinivasa Rao, K.

2018-03-01

The present work pertains to the study of corrosion behavior of aluminum alloy electron beam welds. The aluminium alloy used in the present study is copper containing AA2014 alloy. Electron Beam Welding (EBW) was used to weld the alloys in annealed (O) condition. Microstructural changes across the welds were recorded and the effect of post weld heat treatment (PWHT) in T4 (Solutionized and naturally aged) condition on pitting corrosion resistance was studied. A software based PAR basic electrochemical system was used for potentio-dynamic polarization tests. From the study it is observed that weld in O condition is prone to more liquation than that of PWHT condition. This may be attributed to re-melting and solidification of excess eutectic present in the O condition of the base metal. It was also observed that slightly higher hardness values are recorded in O condition than that of PWHT condition. The pitting corrosion resistance of the PMZ/HAZ in PWHT condition is better than that of O condition. This is attributed to copper segregation at the grain boundaries of PMZ in O condition.

Thermal shock induced dynamics of a spacecraft with a flexible deploying boom

NASA Astrophysics Data System (ADS)

Shen, Zhenxing; Li, Huijian; Liu, Xiaoning; Hu, Gengkai

2017-12-01

The dynamics in the process of deployment of a flexible extendible boom as a deployable structure on the spacecraft is studied. For determining the thermally induced vibrations of the boom subjected to an incident solar heat flux, an axially moving thermal-dynamic beam element based on the absolute nodal coordinate formulation which is able to precisely describe the large displacement, rotation and deformation of flexible body is presented. For the elastic forces formulation of variable-length beam element, the enhanced continuum mechanics approach is adopted, which can eliminate the Poisson locking effect, and take into account the tension-bending-torsion coupling deformations. The main body of the spacecraft, modeled as a rigid body, is described using the natural coordinates method. In the derived nonlinear thermal-dynamic equations of rigid-flexible multibody system, the mass matrix is time-variant, and a pseudo damping matrix which is without actual energy dissipation, and a heat conduction matrix which is relative to the moving speed and the number of beam element are arisen. Numerical results give the dynamic and thermal responses of the nonrotating and spinning spacecraft, respectively, and show that thermal shock has a significant influence on the dynamics of spacecraft.

Prospects for Alpha Particle Heating in JET in the Hot Ion Regime

NASA Astrophysics Data System (ADS)

Cordey, J. G.; Keilhacker, M.; Watkins, M. L.

1987-01-01

The prospects for alpha particle heating in JET are discussed. A computational model is developed to represent adequately the neutron yield from JET plasmas heated by neutral beam injection. This neutral beam model, augmented by a simple plasma model, is then used to determine the neutron yields and fusion Q-values anticipated for different heating schemes in future operation of JET with tritium. The relative importance of beam-thermal and thermal-thermal reactions is pointed out and the dependence of the results on, for example, plasma density, temperature, energy confinement and purity is shown. Full 1½-D transport code calculations, based on models developed for ohmic, ICRF and NBI heated JET discharges, are used also to provide a power scan for JET operation in tritium in the low density, high ion temperature regime. The results are shown to be in good agreement with the estimates made using the simple plasma model and indicate that, based on present knowledge, a fusion Q-value in the plasma centre above unity should be achieved in JET.

Laser beam joining of optical fibers in silicon V-grooves

NASA Astrophysics Data System (ADS)

Kaufmann, Stefan; Otto, Andreas; Luz, Gerhard

2000-06-01

The increasing use of optical data transmission systems and the development of new optical components require adjustment-insensitive and reliable joining and assembling techniques. The state of the art includes the utilization of silicon submounts with anisotropically etched V-grooves. Several glass fibers are fixed in these V-grooves with adhesive. Adhesive bonds tend towards degradation under the influence of temperature and moisture. For this reason, the alternative joining processes laser beam welding and laser beam soldering are relevant. The goal is a reliable joining of optical fibers in V-grooves without damage to the fibers or the silicon submount. Because of the anomaly of silicon during phase transformation, a positive joining can be realized by laser beam welding. A melt pool is created through the energy of a Nd:YAG-laser pulse. During solidification, the volume of silicon increases and a bump is formed in the center. Experiments have shown that this phenomenon can be used for joining optical fibers in silicon-V-grooves. With suitable parameters the silicon flows half around the fiber during solidification. For each fiber, several welding points are necessary. Another promising joining method is laser bema soldering. In this case, a second silicon sheet with a solder deposit is placed on the fibers which lie in the V-grooves of the metallized silicon submount. The laser heats the upper silicon until the solder metals by heat conduction.

Toroidal midplane neutral beam armor and plasma limiter

DOEpatents

Kugel, Henry W.; Hand Jr, Samuel W.; Ksayian, Haig

1986-02-04

For use in a tokamak fusion reactor having a midplane magnetic coil on the inner wall of an evacuated toriodal chamber within which a neutral beam heated, fusing plasma is magnetically confined, a neutral beam armor shield and plasma limiter is provided on the inner wall of the toroidal chamber to shield the midplane coil from neutral beam shine-thru and plasma deposition. The armor shield/plasma limiter forms a semicircular enclosure around the midplane coil with the outer surface of the armor shield/plasma limiter shaped to match, as closely as practical, the inner limiting magnetic flux surface of the toroidally confined, indented, bean-shaped plasma. The armor shield/plasma limiter includes a plurality of semicircular graphite plates each having a pair of coupled upper and lower sections with each plate positioned in intimate contact with an adjacent plate on each side thereof so as to form a closed, planar structure around the entire outer periphery of the circular midplane coil. The upper and lower plate sections are adapted for coupling to heat sensing thermocouples and to a circulating water conduit system for cooling the armor shield/plasma limiter.The inner center portion of each graphite plate is adapted to receive and enclose a section of a circular diagnostic magnetic flux loop so as to minimize the power from the plasma confinement chamber incident upon the flux loop.

Toroidal midplane neutral beam armor and plasma limiter

DOEpatents

Kugel, Henry W.; Hand, Jr, Samuel W.; Ksayian, Haig

1986-01-01

For use in a tokamak fusion reactor having a midplane magnetic coil on the inner wall of an evacuated toriodal chamber within which a neutral beam heated, fusing plasma is magnetically confined, a neutral beam armor shield and plasma limiter is provided on the inner wall of the toroidal chamber to shield the midplane coil from neutral beam shine-thru and plasma deposition. The armor shield/plasma limiter forms a semicircular enclosure around the midplane coil with the outer surface of the armor shield/plasma limiter shaped to match, as closely as practical, the inner limiting magnetic flux surface of the toroidally confined, indented, bean-shaped plasma. The armor shield/plasma limiter includes a plurality of semicircular graphite plates each having a pair of coupled upper and lower sections with each plate positioned in intimate contact with an adjacent plate on each side thereof so as to form a closed, planar structure around the entire outer periphery of the circular midplane coil. The upper and lower plate sections are adapted for coupling to heat sensing thermocouples and to a circulating water conduit system for cooling the armor shield/plasma limiter.The inner center portion of each graphite plate is adapted to receive and enclose a section of a circular diagnostic magnetic flux loop so as to minimize the power from the plasma confinement chamber incident upon the flux loop.

Beam shaping in high-power laser systems with using refractive beam shapers

NASA Astrophysics Data System (ADS)

Laskin, Alexander; Laskin, Vadim

2012-06-01

Beam Shaping of the spatial (transverse) profile of laser beams is highly desirable by building optical systems of high-power lasers as well in various applications with these lasers. Pumping of the crystals of Ti:Sapphire lasers by the laser radiation with uniform (flattop) intensity profile improves performance of these ultrashort pulse high-power lasers in terms of achievable efficiency, peak-power and stability, output beam profile. Specifications of the solid-state lasers built according to MOPA configuration can be also improved when radiation of the master oscillator is homogenized and then is amplified by the power amplifier. Features of building these high power lasers require that a beam shaping solution should be capable to work with single mode and multimode beams, provide flattop and super-Gauss intensity distributions, the consistency and divergence of a beam after the intensity re-distribution should be conserved and low absorption provided. These specific conditions are perfectly fulfilled by the refractive field mapping beam shapers due to their unique features: almost lossless intensity profile transformation, low output divergence, high transmittance and flatness of output beam profile, extended depth of field, adaptability to real intensity profiles of TEM00 and multimode laser sources. Combining of the refractive field mapping beam shapers with other optical components, like beam-expanders, relay imaging lenses, anamorphic optics makes it possible to generate the laser spots of necessary shape, size and intensity distribution. There are plenty of applications of high-power lasers where beam shaping bring benefits: irradiating photocathode of Free Electron Lasers (FEL), material ablation, micromachining, annealing in display making techniques, cladding, heat treating and others. This paper will describe some design basics of refractive beam shapers of the field mapping type, with emphasis on the features important for building and applications of high-power laser sources. There will be presented results of applying the refractive beam shapers in real installations.

High-resolution recording of particle tracks with in-line holography in a large cryogenic bubble chamber

NASA Astrophysics Data System (ADS)

Harigel, Gert G.

2000-10-01

Holography has been used successfully in combination with conventional optics for the first time in a large cryogenic bubble chamber, the 15-Foot Bubble Chamber at the Fermi National Accelerator Laboratory (FNAL), during a physics run in a high energy neutrino beam. The innovative system combined the reference beam with the object beam, irradiating a conical volume of approx1.5m3. Bubble tracks from neutrino interactions with a width of approx 120 micrometers have been recorded with good contrast. The ratio of intensities of the object light to the reference light striking the film is called the beam branching ratio (BBR). We obtained in our experiment an exceedingly small minimum- observable ration of BBR = (0.54 divided by 0.21) x 107. The technology has the potential for a wide range of applications. This paper describes the various difficulties in achieving the success. It required the development of laser pulse stretching via enhanced closed loop control with slow Q- switching, to overcome excessive heating of the cryogenic liquid by the powerful laser beam. A sophisticated system of light-absorbing baffles had to be installed to avoid stray light reaching the holographic film. Optical decoupling of classical and holographic illumination systems was required. Real and virtual image replay machines for holograms were built, tailored to our illumination technique.

Computational simulation of laser heat processing of materials

NASA Astrophysics Data System (ADS)

Shankar, Vijaya; Gnanamuthu, Daniel

1987-04-01

A computational model simulating the laser heat treatment of AISI 4140 steel plates with a CW CO2 laser beam has been developed on the basis of the three-dimensional, time-dependent heat equation (subject to the appropriate boundary conditions). The solution method is based on Newton iteration applied to a triple-approximate factorized form of the equation. The method is implicit and time-accurate; the maintenance of time-accuracy in the numerical formulation is noted to be critical for the simulation of finite length workpieces with a finite laser beam dwell time.

The 10 MWe Solar Thermal Central Receiver Pilot Plant: Solar facilities design integration. Pilot-plant station manual (RADL Item 2-1). Volume 1: System description

NASA Astrophysics Data System (ADS)

1982-09-01

The complete Barstow Solar Pilot Plant is described. The plant requirements and general description are presented, the mechanical, electric power, and control and instrumentation systems as well as civil engineering and structural aspects and the station buildings are described. Included in the mechanical systems are the heliostats, receiver, thermal storage system, beam characterization system, steam, water, nitrogen, and compressed air systems, chemical feed system, fire protection system, drains, sumps and the waste disposal systems, and heating, ventilating, and air conditioning systems.

Development of a simultaneous SANS / FTIR measuring system and its application to polymer cocrystals

NASA Astrophysics Data System (ADS)

Kaneko, F.; Seto, N.; Sato, S.; Radulescu, A.; Schiavone, M. M.; Allgaier, J.; Ute, K.

2016-09-01

In order to provide plenty of structure information which would assist in the analysis and interpretation of small angle neutron scattering (SANS) profile, a novel method for the simultaneous time-resolved measurement of SANS and Fourier transform infrared (FTIR) spectroscopy has been developed. The method was realized by building a device consisting of a portable FTIR spectrometer and an optical system equipped with two aluminum coated quartz plates that are fully transparent to neutron beams but play as mirrors for infrared radiation. The optical system allows both a neutron beam and an infrared beam pass through the same position of a test specimen coaxially. The device was installed on a small angle neutron diffractometer, KWS2 of the Jülich Centre for Neutron Science (JCNS) outstation at Heinz Maier-Leibnitz Center (MLZ) in Garching, Germany. In order to check the performance of this simultaneous measuring system, the structural changes in the cocrystals of syndiotactic polystyrene during the course of heating were followed. It has been confirmed that FTIR spectra measured in parallel are able to provide information about the behavior of each component and also useful to grasp in real time what is actually happening in the sample system.

Magnetic reconnection in plasma under inertial confinement fusion conditions driven by heat flux effects in Ohm's law.

PubMed

Joglekar, A S; Thomas, A G R; Fox, W; Bhattacharjee, A

2014-03-14

In the interaction of high-power laser beams with solid density plasma there are a number of mechanisms that generate strong magnetic fields. Such fields subsequently inhibit or redirect electron flows, but can themselves be advected by heat fluxes, resulting in complex interplay between thermal transport and magnetic fields. We show that for heating by multiple laser spots reconnection of magnetic field lines can occur, mediated by these heat fluxes, using a fully implicit 2D Vlasov-Fokker-Planck code. Under such conditions, the reconnection rate is dictated by heat flows rather than Alfvènic flows. We find that this mechanism is only relevant in a high β plasma. However, the Hall parameter ωcτei can be large so that thermal transport is strongly modified by these magnetic fields, which can impact longer time scale temperature homogeneity and ion dynamics in the system.

The Laser Atmospheric Wind Sounder (LAWS) Phase 2 Preliminary Laser Design

NASA Technical Reports Server (NTRS)

Lawrence, T. Rhidian; Pindroh, Albert L.; Bowers, Mark S.; Dehart, Terence E.; Mcdonald, Kenneth F.; Cousins, Ananda; Moody, Stephen E.

1992-01-01

The requirements for the Laser Atmospheric Wind Sounder (LAWS) were determined from system considerations and are summarized in tabular form. The laser subsystem provides for the generation and frequency control of two beams, the transmit high power and local oscillator beams, which are delivered to the optical and receiver subsystems, respectively. In our baseline approach, the excitation of the gain section is achieved by a self-sustaining uv-(corona) preionized discharge. Gas is recirculated within the laser loop using a transverse flow fan. An intra-flow-loop heat exchanger, catalyst monolith, and acoustic attenuators condition the gas to ensure uniform energy output and high beam quality during high pulse repetition rate operation. The baseline LAWS laser pulse temporal profile as calculated by in-house laser codes is given in graphical form.

A tangentially viewing fast ion D-alpha diagnostic for NSTX.

PubMed

Bortolon, A; Heidbrink, W W; Podestà, M

2010-10-01

A second fast ion D-alpha (FIDA) installation is planned at NSTX to complement the present perpendicular viewing FIDA diagnostics. Following the present diagnostic scheme, the new diagnostic will consist of two instruments: a spectroscopic diagnostic that measures fast ion spectra and profiles at 16 radial points with 5-10 ms resolution and a system that uses a band pass filter and photomultiplier to measure changes in FIDA light with 50 kHz sampling rate. The new pair of FIDA instruments will view the heating beams tangentially. The viewing geometry minimizes spectral contamination by beam emission or edge sources of background emission. The improved velocity-space resolution will provide detailed information about neutral-beam current drive and about fast ion acceleration and transport by injected radio frequency waves and plasma instabilities.

Spectrophotovoltaic orbital power generation

NASA Technical Reports Server (NTRS)

Onffroy, J. R.

1980-01-01

The feasibilty of a spectrophotovoltaic orbital power generation system that optically concentrates solar energy is demonstrated. A dichroic beam-splitting mirror is used to divide the solar spectrum into two wavebands. Absorption of these wavebands by GaAs and Si solar cell arrays with matched energy bandgaps increases the cell efficiency while decreasing the amount of heat that must be rejected. The projected cost per peak watt if this system is $2.50/W sub p.

Cavitation damage prediction for spallation target vessels by assessment of acoustic vibration

DOE Office of Scientific and Technical Information (OSTI.GOV)

Futakawa, Masatoshi; Kogawa, Hiroyuki; Hasegawa, Shoichi

2008-01-01

Liquid-mercury target systems for MW-class spallation neutron sources are being developed around the world. Proton beams are used to induce the spallation reaction. At the moment the proton beam hits the target, pressure waves are generated in the mercury because of the abrupt heat deposition. The pressure waves interact with the target vessel leading to negative pressure that may cause cavitation along the vessel wall. In order to estimate the cavitation erosion, i.e. the pitting damage formed by the collapse of cavitation bubbles, off-beam tests were performed by using an electric magnetic impact testing machine (MIMTM), which can impose equivalentmore » pressure pulses in mercury. The damage potential was defined based on the relationship between the pitting damage and the time-integrated acoustic vibration induced by impact due to the bubble collapses. Additionally, the damage potential was measured in on-beam tests carried out by using the proton beam at WNR (Weapons Neutron Research) facility in Los Alamos Neutron Science Center (LANSCE). In this paper, the concept of the damage potential, the relationship between the pitting damage formation and the damage potential both in off-beam and on-beam tests is shown.« less

Ion collector design for an energy recovery test proposal with the negative ion source NIO1

DOE Office of Scientific and Technical Information (OSTI.GOV)

Variale, V., E-mail: vincenzo.variale@ba.infn.it; Cavenago, M.; Agostinetti, P.

2016-02-15

Commercial viability of thermonuclear fusion power plants depends also on minimizing the recirculation power used to operate the reactor. The neutral beam injector (NBI) remains one of the most important method for plasma heating and control. For the future fusion power plant project DEMO, a NBI wall plug efficiency at least of 0.45 is required, while efficiency of present NBI project is about 0.25. The D{sup −} beam from a negative ion source is partially neutralized by a gas cell, which leaves more than 40% of energy in residual beams (D{sup −} and D{sup +}), so that an ion beammore » energy recovery system can significantly contribute to optimize efficiency. Recently, the test negative ion source NIO1 (60 keV, 9 beamlets with 15 mA H{sup −} each) has been designed and built at RFX (Padua) for negative ion production efficiency and the beam quality optimization. In this paper, a study proposal to use the NIO1 source also for a beam energy recovery test experiment is presented and a preliminary design of a negative ion beam collector with simulations of beam energy recovery is discussed.« less

Structural Integration of Sensors/Actuators by Laser Beam Melting for Tailored Smart Components

NASA Astrophysics Data System (ADS)

Töppel, Thomas; Lausch, Holger; Brand, Michael; Hensel, Eric; Arnold, Michael; Rotsch, Christian

2018-03-01

Laser beam melting (LBM), an additive laser powder bed fusion technology, enables the structural integration of temperature-sensitive sensors and actuators in complex monolithic metallic structures. The objective is to embed a functional component inside a metal part without losing its functionality by overheating. The first part of this paper addresses the development of a new process chain for bonded embedding of temperature-sensitive sensor/actuator systems by LBM. These systems are modularly built and coated by a multi-material/multi-layer thermal protection system of ceramic and metallic compounds. The characteristic of low global heat input in LBM is utilized for the functional embedding. In the second part, the specific functional design and optimization for tailored smart components with embedded functionalities are addressed. Numerical and experimental validated results are demonstrated on a smart femoral hip stem.

Minimal excitation states for heat transport in driven quantum Hall systems

NASA Astrophysics Data System (ADS)

Vannucci, Luca; Ronetti, Flavio; Rech, Jérôme; Ferraro, Dario; Jonckheere, Thibaut; Martin, Thierry; Sassetti, Maura

2017-06-01

We investigate minimal excitation states for heat transport into a fractional quantum Hall system driven out of equilibrium by means of time-periodic voltage pulses. A quantum point contact allows for tunneling of fractional quasiparticles between opposite edge states, thus acting as a beam splitter in the framework of the electron quantum optics. Excitations are then studied through heat and mixed noise generated by the random partitioning at the barrier. It is shown that levitons, the single-particle excitations of a filled Fermi sea recently observed in experiments, represent the cleanest states for heat transport since excess heat and mixed shot noise both vanish only when Lorentzian voltage pulses carrying integer electric charge are applied to the conductor. This happens in the integer quantum Hall regime and for Laughlin fractional states as well, with no influence of fractional physics on the conditions for clean energy pulses. In addition, we demonstrate the robustness of such excitations to the overlap of Lorentzian wave packets. Even though mixed and heat noise have nonlinear dependence on the voltage bias, and despite the noninteger power-law behavior arising from the fractional quantum Hall physics, an arbitrary superposition of levitons always generates minimal excitation states.

The Earth's mantle in a microwave oven: thermal convection driven by a heterogeneous distribution of heat sources

NASA Astrophysics Data System (ADS)

Fourel, Loïc; Limare, Angela; Jaupart, Claude; Surducan, Emanoil; Farnetani, Cinzia G.; Kaminski, Edouard C.; Neamtu, Camelia; Surducan, Vasile

2017-08-01

Convective motions in silicate planets are largely driven by internal heat sources and secular cooling. The exact amount and distribution of heat sources in the Earth are poorly constrained and the latter is likely to change with time due to mixing and to the deformation of boundaries that separate different reservoirs. To improve our understanding of planetary-scale convection in these conditions, we have designed a new laboratory setup allowing a large range of heat source distributions. We illustrate the potential of our new technique with a study of an initially stratified fluid involving two layers with different physical properties and internal heat production rates. A modified microwave oven is used to generate a uniform radiation propagating through the fluids. Experimental fluids are solutions of hydroxyethyl cellulose and salt in water, such that salt increases both the density and the volumetric heating rate. We determine temperature and composition fields in 3D with non-invasive techniques. Two fluorescent dyes are used to determine temperature. A Nd:YAG planar laser beam excites fluorescence, and an optical system, involving a beam splitter and a set of colour filters, captures the fluorescence intensity distribution on two separate spectral bands. The ratio between the two intensities provides an instantaneous determination of temperature with an uncertainty of 5% (typically 1K). We quantify mixing processes by precisely tracking the interfaces separating the two fluids. These novel techniques allow new insights on the generation, morphology and evolution of large-scale heterogeneities in the Earth's lower mantle.

Investigating scintillometer source areas

NASA Astrophysics Data System (ADS)

Perelet, A. O.; Ward, H. C.; Pardyjak, E.

2017-12-01

Scintillometry is an indirect ground-based method for measuring line-averaged surface heat and moisture fluxes on length scales of 0.5 - 10 km. These length scales are relevant to urban and other complex areas where setting up traditional instrumentation like eddy covariance is logistically difficult. In order to take full advantage of scintillometry, a better understanding of the flux source area is needed. The source area for a scintillometer is typically calculated as a convolution of point sources along the path. A weighting function is then applied along the path to compensate for a total signal contribution that is biased towards the center of the beam path, and decreasing near the beam ends. While this method of calculating the source area provides an estimate of the contribution of the total flux along the beam, there are still questions regarding the physical meaning of the weighted source area. These questions are addressed using data from an idealized experiment near the Salt Lake City International Airport in northern Utah, U.S.A. The site is a flat agricultural area consisting of two different land uses. This simple heterogeneity in the land use facilitates hypothesis testing related to source areas. Measurements were made with a two wavelength scintillometer system spanning 740 m along with three standard open-path infrared gas analyzer-based eddy-covariance stations along the beam path. This configuration allows for direct observations of fluxes along the beam and comparisons to the scintillometer average. The scintillometer system employed measures the refractive index structure parameter of air for two wavelengths of electromagnetic radiation, 880 μm and 1.86 cm to simultaneously estimate path-averaged heat and moisture fluxes, respectively. Meteorological structure parameters (CT2, Cq2, and CTq) as well as surface fluxes are compared for various amounts of source area overlap between eddy covariance and scintillometry. Additionally, surface properties from LANDSAT 7 & 8 are used to help understand source area composition for different times throughout the experiment.

Isochoric heating of solid gold targets with the PW-laser-driven ion beams

NASA Astrophysics Data System (ADS)

Steinke, Sven; Ji, Qing; Bulanov, Stepan; Barnard, John; Schenkel, Thomas; Esarey, Eric; Leemans, Wim

2016-10-01

We present an end-to-end simulation for isochoric heating of solid gold targets using ion beams produced with the BELLA PW laser at LBNL: (i) 2D Particle-In-Cell (PIC) simulations are applied to study the ion source characteristics of the PW laser-target interaction at the long focal length (f/#65) beamline at laser intensities of 5x1019W/cm2 at spot size of ω0 = 52 μm on a CH target. (ii) In order to transport the ion beams to an EMP-free environment, an active plasma lens will be used. This was modeled by calculating the Twiss parameters of the ion beam from the appropriate transport matrixes using the source parameters obtained from the PIC simulation. Space charge effects were considered as well. (iii) Hydrodynamic simulations indicate that these ion beams can isochorically heat a 1 mm3 gold target to the Warm Dense Matter state. This work was supported by Fusion Energy Science, and LDRD funding from Lawrence Berkeley National Laboratory, provided by the Director, Office of Science, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.

Plant model of KIPT neutron source facility simulator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cao, Yan; Wei, Thomas Y.; Grelle, Austin L.

2016-02-01

Argonne National Laboratory (ANL) of the United States and Kharkov Institute of Physics and Technology (KIPT) of Ukraine are collaborating on constructing a neutron source facility at KIPT, Kharkov, Ukraine. The facility has 100-kW electron beam driving a subcritical assembly (SCA). The electron beam interacts with a natural uranium target or a tungsten target to generate neutrons, and deposits its power in the target zone. The total fission power generated in SCA is about 300 kW. Two primary cooling loops are designed to remove 100-kW and 300-kW from the target zone and the SCA, respectively. A secondary cooling system ismore » coupled with the primary cooling system to dispose of the generated heat outside the facility buildings to the atmosphere. In addition, the electron accelerator has a low efficiency for generating the electron beam, which uses another secondary cooling loop to remove the generated heat from the accelerator primary cooling loop. One of the main functions the KIPT neutron source facility is to train young nuclear specialists; therefore, ANL has developed the KIPT Neutron Source Facility Simulator for this function. In this simulator, a Plant Control System and a Plant Protection System were developed to perform proper control and to provide automatic protection against unsafe and improper operation of the facility during the steady-state and the transient states using a facility plant model. This report focuses on describing the physics of the plant model and provides several test cases to demonstrate its capabilities. The plant facility model uses the PYTHON script language. It is consistent with the computer language of the plant control system. It is easy to integrate with the simulator without an additional interface, and it is able to simulate the transients of the cooling systems with system control variables changing on real-time.« less

Ion-beam doping of GaAs with low-energy (100 eV) C + using combined ion-beam and molecular-beam epitaxy

NASA Astrophysics Data System (ADS)

Iida, Tsutomu; Makita, Yunosuke; Kimura, Shinji; Winter, Stefan; Yamada, Akimasa; Fons, Paul; Uekusa, Shin-ichiro

1995-01-01

A combined ion-beam and molecular-beam-epitaxy (CIBMBE) system has been developed. This system consists of an ion implanter capable of producing ions in the energy range of 30 eV-30 keV and conventional solid-source MBE. As a successful application of CIBMBE, low-energy (100 eV) carbon ion (C+) irradiation during MBE growth of GaAs was carried out at substrate temperatures Tg between 500 and 590 °C. C+-doped layers were characterized by low-temperature (2 K) photoluminescence (PL), Raman scattering, and van der Pauw measurements. PL spectra of undoped GaAs grown by CIBMBE revealed that unintentional impurity incorporation into the epilayer is extremely small and precise doping effects are observable. CAs acceptor-related emissions such as ``g,'' [g-g], and [g-g]β are observed and their spectra are significantly changed with increasing C+ beam current density Ic. PL measurements showed that C atoms were efficiently incorporated during MBE growth by CIBMBE and were optically well activated as an acceptor in the as-grown condition even for Tg as low as 500 °C. Raman measurement showed negligible lattice damage of the epilayer bombarded with 100 eV C+ with no subsequent heat treatment. These results indicate that contamination- and damage-free impurity doping without postgrowth annealing can be achieved by the CIBMBE method.

Status of a Power Processor for the Prometheus-1 Electric Propulsion System

NASA Technical Reports Server (NTRS)

Pinero, Luis R.; Hill, Gerald M.; Aulisio, Michael; Gerber, Scott; Griebeler, Elmer; Hewitt, Frank; Scina, Joseph

2006-01-01

NASA is developing technologies for nuclear electric propulsion for proposed deep space missions in support of the Exploration initiative under Project Prometheus. Electrical power produced by the combination of a fission-based power source and a Brayton power conversion and distribution system is used by a high specific impulse ion propulsion system to propel the spaceship. The ion propulsion system include the thruster, power processor and propellant feed system. A power processor technology development effort was initiated under Project Prometheus to develop high performance and lightweight power-processing technologies suitable for the application. This effort faces multiple challenges including developing radiation hardened power modules and converters with very high power capability and efficiency to minimize the impact on the power conversion and distribution system as well as the heat rejection system. This paper documents the design and test results of the first version of the beam supply, the design of a second version of the beam supply and the design and test results of the ancillary supplies.

Nonlinear interaction of strong microwave beam with the ionosphere MINIX rocket experiment

NASA Astrophysics Data System (ADS)

Kaya, N.; Matsumoto, H.; Miyatake, S.; Kimura, I.; Nagatomo, M.

A rocket-borne experiment called 'MINIX' was carried out to investigate the nonlinear interaction of a strong microwave energy beam with the ionosphere. The MINIX stands for Microwave-Ionosphere Nonlinear Interaction eXperiment and was carried out on August 29, 1983. The objective of the MINIX is to study possible impacts of the SPS microwave energy beam on the ionosphere, such as the ohmic heating and plasma wave excitation. The experiment showed that the microwave with f = 2.45 GHz nonlinearly excites various electrostatic plasma waves, though no ohmic heating effects were detected.

Temperature profiles induced by a stationary CW laser beam in a multi-layer structure - Application to solar cell interconnect welding

NASA Astrophysics Data System (ADS)

Oh, J. E.; Ianno, N. J.; Ahmed, A. U.

A three-dimensional heat transfer model for heating of a multilayer structure by a stationary Gaussian CW CO2 laser beam is developed and applied to solar cell interconnect welding. This model takes into account the temperature dependence of the thermal conductivity and diffusivity as well as free carrier absorption of the incident beam in the silicon where appropriate. Finally, the theoretical temperature profiles are used to determine the weld spot size and these values are compared to results obtained from a simple welding experiment, where excellent agreement is obtained.

Theoretical and experimental research on laser-beam homogenization based on metal gauze

NASA Astrophysics Data System (ADS)

Liu, Libao; Zhang, Shanshan; Wang, Ling; Zhang, Yanchao; Tian, Zhaoshuo

2018-03-01

Method of homogenization of CO2 laser heating by means of metal gauze is researched theoretically and experimentally. Distribution of light-field of expanded beam passing through metal gauze was numerically calculated with diffractive optical theory and the conclusion is that method is effective, with comparing the results to the situation without metal gauze. Experimentally, using the 30W DC discharge laser as source and enlarging beam by concave lens, with and without metal gauze, beam intensity distributions in thermal paper were compared, meanwhile the experiments based on thermal imager were performed. The experimental result was compatible with theoretical calculation, and all these show that the homogeneity of CO2 laser heating could be enhanced by metal gauze.

Beam heating of thick targets for on-line mass separators

NASA Astrophysics Data System (ADS)

Eaton, T. W.; Ravn, H. L.; Isolde Collaboration

1987-05-01

Energy deposition computations have been made on a variety of target materials utilized for the production of radioisotopes by means of 600-MeV protons. Results have shown that, when a proton current of 100 μA is assumed, dispersed target materials, such as uranium carbide powder and magnesium oxide, are best able to withstand the energy absorption and consequent beam heating without the need of additional cooling. Modified foil targets of titanium, zirconium and tantalum also appear capable of withstanding a full beam current, whilst liquid metal targets in their present form appear to have limitations in terms of the maximum allowable beam current. A redesign of the target container is proposed which allows higher proton currents to be used with these targets also.

Analysis of the beam halo in negative ion sources by using 3D3V PIC code

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miyamoto, K., E-mail: kmiyamot@naruto-u.ac.jp; Nishioka, S.; Goto, I.

The physical mechanism of the formation of the negative ion beam halo and the heat loads of the multi-stage acceleration grids are investigated with the 3D PIC (particle in cell) simulation. The following physical mechanism of the beam halo formation is verified: The beam core and the halo consist of the negative ions extracted from the center and the periphery of the meniscus, respectively. This difference of negative ion extraction location results in a geometrical aberration. Furthermore, it is shown that the heat loads on the first acceleration grid and the second acceleration grid are quantitatively improved compared with thosemore » for the 2D PIC simulation result.« less

Optimized undulator to generate low energy photons from medium to high energy accelerators

NASA Astrophysics Data System (ADS)

Chung, Ting-Yi; Chiu, Mau-Sen; Luo, Hao-Wen; Yang, Chin-Kang; Huang, Jui-Che; Jan, Jyh-Chyuan; Hwang, Ching-Shiang

2017-07-01

While emitting low energy photons from a medium or high energy storage ring, the on-axis heat load on the beam line optics can become a critical issue. In addition, the heat load in the bending magnet chamber, especially in the vertical and circular polarization mode of operation may cause some concern. In this work, we compare the heat loads for the APPLE-II and the Knot-APPLE, both optimized to emit 10 eV photons from the 3 GeV TPS. Under this constraint the heat load analysis, synchrotron radiation performance and features in various polarization modes are presented. Additional consideration is given to beam dynamics effect.

MEMS-based, RF-driven, compact accelerators

NASA Astrophysics Data System (ADS)

Persaud, A.; Seidl, P. A.; Ji, Q.; Breinyn, I.; Waldron, W. L.; Schenkel, T.; Vinayakumar, K. B.; Ni, D.; Lal, A.

2017-10-01

Shrinking existing accelerators in size can reduce their cost by orders of magnitude. Furthermore, by using radio frequency (RF) technology and accelerating ions in several stages, the applied voltages can be kept low paving the way to new ion beam applications. We make use of the concept of a Multiple Electrostatic Quadrupole Array Linear Accelerator (MEQALAC) and have previously shown the implementation of its basic components using printed circuit boards, thereby reducing the size of earlier MEQALACs by an order of magnitude. We now demonstrate the combined integration of these components to form a basic accelerator structure, including an initial beam-matching section. In this presentation, we will discuss the results from the integrated multi-beam ion accelerator and also ion acceleration using RF voltages generated on-board. Furthermore, we will show results from Micro-Electro-Mechanical Systems (MEMS) fabricated focusing wafers, which can shrink the dimension of the system to the sub-mm regime and lead to cheaper fabrication. Based on these proof-of-concept results we outline a scaling path to high beam power for applications in plasma heating in magnetized target fusion and in neutral beam injectors for future Tokamaks. This work was supported by the Office of Science of the US Department of Energy through the ARPA-e ALPHA program under contracts DE-AC02-05CH11231.

Prototyping Control and Data Acquisition for the ITER Neutral Beam Test Facility

NASA Astrophysics Data System (ADS)

Luchetta, Adriano; Manduchi, Gabriele; Taliercio, Cesare; Soppelsa, Anton; Paolucci, Francesco; Sartori, Filippo; Barbato, Paolo; Breda, Mauro; Capobianco, Roberto; Molon, Federico; Moressa, Modesto; Polato, Sandro; Simionato, Paola; Zampiva, Enrico

2013-10-01

The ITER Neutral Beam Test Facility will be the project's R&D facility for heating neutral beam injectors (HNB) for fusion research operating with H/D negative ions. Its mission is to develop technology to build the HNB prototype injector meeting the stringent HNB requirements (16.5 MW injection power, -1 MeV acceleration energy, 40 A ion current and one hour continuous operation). Two test-beds will be built in sequence in the facility: first SPIDER, the ion source test-bed, to optimize the negative ion source performance, second MITICA, the actual prototype injector, to optimize ion beam acceleration and neutralization. The SPIDER control and data acquisition system is under design. To validate the main architectural choices, a system prototype has been assembled and performance tests have been executed to assess the prototype's capability to meet the control and data acquisition system requirements. The prototype is based on open-source software frameworks running under Linux. EPICS is the slow control engine, MDSplus is the data handler and MARTe is the fast control manager. The prototype addresses low and high-frequency data acquisition, 10 kS/s and 10 MS/s respectively, camera image acquisition, data archiving, data streaming, data retrieval and visualization, real time fast control with 100 μs control cycle and supervisory control.

Radiation-driven rotational motion of nanoparticles

DOE PAGES

Liang, Mengning; Harder, Ross; Robinson, Ian

2018-04-25

Focused synchrotron beams can influence a studied sample via heating, or radiation pressure effects due to intensity gradients. The high angular sensitivity of rotational X-ray tracking (RXT) of crystalline particles via their Bragg reflections can detect extremely small forces such as those caused by field gradients. By tracking the rotational motion of single crystal nanoparticles embedded in a viscous or viscoelastic medium, we observed the effects of heating in a uniform gradient beam and radiation pressure in a Gaussian profile beam. Heating of a few degrees Celsius was measured for 42μm crystals in glycerol and angular velocities of 10 -6rad/smore » due to torques of 10 - 24N∙m were measured for 340nm crystals in a colloidal gel matrix. These results show the ability to quantify small forces using rotation motion of tracer particles.« less

Radiation-driven rotational motion of nanoparticles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liang, Mengning; Harder, Ross; Robinson, Ian

Focused synchrotron beams can influence a studied sample via heating, or radiation pressure effects due to intensity gradients. The high angular sensitivity of rotational X-ray tracking (RXT) of crystalline particles via their Bragg reflections can detect extremely small forces such as those caused by field gradients. By tracking the rotational motion of single crystal nanoparticles embedded in a viscous or viscoelastic medium, we observed the effects of heating in a uniform gradient beam and radiation pressure in a Gaussian profile beam. Heating of a few degrees Celsius was measured for 42μm crystals in glycerol and angular velocities of 10 -6rad/smore » due to torques of 10 - 24N∙m were measured for 340nm crystals in a colloidal gel matrix. These results show the ability to quantify small forces using rotation motion of tracer particles.« less

Measurements of fluctuating gas temperatures using compensated fine wire thermocouples

NASA Astrophysics Data System (ADS)

Nina, M. N. R.; Pita, G. P.

1985-09-01

Thermocouples with three different wire diameters (15, 40 and 50 microns) were used in association with an analog compensation circuit connected to a data acquisition system. Measurements of the time constant were performed using two different heating techniques; Joule effect and external heating by laser beam. The thermocouples were used to quantify the fluctuating temperature field in a hot air jet and in a premixed propane flame. In the reacting case the catalytic effect was evaluated by comparing coated and uncoated wires. Conclusions were also obtained regarding frequency spectra, temperature probability distribution function and time constant.

A combined experimental and numerical approach for the control and monitoring of the SPES target during operation at high temperature

NASA Astrophysics Data System (ADS)

Ballan, Michele; Manzolaro, Mattia; Meneghetti, Giovanni; Andrighetto, Alberto; Monetti, Alberto; Bisoffi, Giovanni; Prete, Gianfranco

2016-06-01

The SPES project at INFN-LNL aims at the production of neutron-rich Radioactive Ion Beams (RIBs) using the ISOL (Isotope Separation On Line) technique. A 40 MeV 200 μA proton beam will directly impinge a uranium carbide target, generating approximately 1013 fissions per second. The target system is installed under vacuum inside a water-cooled chamber, and have to maintain high working temperatures, close to 2000 °C. During operation the proton beam provides the heating power required to keep the target at the desired temperature level. As a consequence, its characteristics have to be strictly controlled in order to avoid undesired overheating. According to the original design of the control system, the proton beam can be suddenly interrupted in case of out of range vacuum or cooling water flow levels. With the aim to improve the reliability of the control system a set of temperature sensors has been installed close to the target. Their types and installation positions were defined taking into consideration the detailed information coming from a dedicated thermal-electric model that allowed to investigate the most critical and inaccessible target hot-spots. This work is focused on the definition and experimental validation of the aforementioned numerical model. Its results were used to appropriately install two type C thermocouples, a PT100 thermo-resistance and a residual primary beam current detector. In addition the numerical model will be used for the definition of appropriate thresholds for each installed temperature sensor, since it allows to define a relationship between the locally measured values with the overall calculated temperature field. In case of over temperatures the monitoring system will send warning signals or in case interrupt the proton beam.

LLE Review Quarterly Report January - March 2012. Volume 130

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shvydky, Alex

2012-03-01

This volume of the LLE Review, covering January–March 2012, features “OMEGA Polar-Drive Target Designs,” by P. B. Radha, J. A. Marozas, F. J. Marshall, A. Shvydky, T. J. B. Collins, V. N. Goncharov, R. L. McCrory, P. W. McKenty, D. D. Meyerhofer, T. C. Sangster, and S. Skupsky. This article (p. 57) describes low-adiabat, cryogenic-deuterium–tritium, and warm-plastic-shell polar-drive (PD)–implosion designs for the OMEGA laser. The designs are at two different on-target laser intensities, each at a different in-flight aspect ratio (IFAR). The first design permits one to study implosion energetics and target performance closer to ignition-relevant intensities (7 X 10more » 14 W/cm 2 at the quarter-critical surface), where nonlocal heat conduction and laser–plasma interactions can play an important role, but at lower values of IFAR (~22). The second design permits one to study implosion energetics and target performance at a lower intensity (3 X 10 14 W/cm 2) but at higher IFAR (~32), where the shell instability can play an important role. The higher IFAR designs are accessible on the existing OMEGA Laser System only at lower intensities. Implosions at ignition-relevant intensities can be obtained only by reducing target radius, although only at smaller values of IFAR. Polar-drive geometry requires repointing the laser beams to improve shell symmetry. The higher-intensity designs optimize target performance by repointing beams to a lesser extent and compensate for the reduced equatorial drive by increasing beam energies for the repointed beams and using custom beam profiles that improve equatorial illumination at the expense of irradiation at higher latitudes. These designs will be studied when new phase plates for the OMEGA Laser System, corresponding to the smaller target radii and custom beam profiles, are obtained. Implosion results from the combined set of high-intensity and high-IFAR implosions should yield valuable data to validate models of laser-energy deposition, heat conduction, nonuniformity growth, and fuel assembly in PD geometry.« less

Laser beam generating apparatus

DOEpatents

Warner, Bruce E.; Duncan, David B.

1993-01-01

Laser beam generating apparatus including a septum segment disposed longitudinally within the tubular structure of the apparatus. The septum provides for radiatively dissipating heat buildup within the tubular structure and for generating relatively uniform laser beam pulses so as to minimize or eliminate radial pulse delays (the chevron effect).

Laser beam generating apparatus

DOEpatents

Warner, Bruce E.; Duncan, David B.

1994-01-01

Laser beam generating apparatus including a septum segment disposed longitudinally within the tubular structure of the apparatus. The septum provides for radiatively dissipating heat buildup within the tubular structure and for generating relatively uniform laser beam pulses so as to minimize or eliminate radial pulse delays (the chevron effect).

BATMAN beam properties characterization by the beam emission spectroscopy diagnostic

NASA Astrophysics Data System (ADS)

Bonomo, F.; Ruf, B.; Barbisan, M.; Cristofaro, S.; Schiesko, L.; Fantz, U.; Franzen, P.; Pasqualotto, R.; Riedl, R.; Serianni, G.; Wünderlich, D.

2015-04-01

The ITER neutral beam heating systems are based on the production and acceleration of negative ions (H/D) up to 1 MV. The requirements for the beam properties are strict: a low core beam divergence (< 0.4 °) together with a low source pressure (≤ 0.3 Pa) would permit to reduce the ion losses along the beamline, keeping the stripping particle losses below 30%. However, the attainment of such beam properties is not straightforward. At IPP, the negative ion source testbed BATMAN (BAvarian Test MAchine for Negative ions) allows for deepening the knowledge of the determination of the beam properties. One of the diagnostics routinely used to this purpose is the Beam Emission Spectroscopy (BES): the Hα light emitted in the beam is detected and the corresponding spectra are evaluated to estimate the beam divergence and the stripping losses. The BES number of lines of sight in BATMAN has been recently increased: five horizontal lines of sight providing a vertical profile of the beam permit to characterize the negative ion beam properties in relation to the source parameters. Different methods of Hα spectra analysis are here taken into account and compared for the estimation of the beam divergence and the amount of stripping. In particular, to thoroughly study the effect of the space charge compensation on the beam divergence, an additional hydrogen injection line has been added in the tank, which allows for setting different background pressure values (one order of magnitude, from about 0.04 Pa up to the source pressure) in the beam drift region.

Collimated thermal radiation transfer via half Maxwell's fish-eye lens for thermophotovoltaics

NASA Astrophysics Data System (ADS)

Chung, Haejun; Zhou, Zhiguang; Bermel, Peter

2017-05-01

Thermophotovoltaics (TPV) convert heat into electricity by capturing thermal radiation with a photovoltaic (PV) cell, ideally at efficiencies of 50% or more. However, excess heating of the PV cell from close proximity to the emitter substantially reduces the system efficiency. In this work, we theoretically develop and numerically demonstrate an approach to fundamentally improving TPV systems that allow for a much greater separation of an emitter and a receiver. Thus, we solve the excess heating dilemma, required for achieving theoretically high efficiencies. It consists of a spherically graded index lens known as Maxwell's Fish-Eye (MFE) structure, capable of collimating hemispherical emission into a much narrower range of angles, close to the normal direction. To fully characterize the power radiation profile of the MFE, we perform finite-difference time-domain simulations for a quarter MFE and then map it onto a Gaussian beam approximation. The modeled beam properties are subsequently used to study a half MFE. In an optimized half MFE design, 90% of all thermal photons reach a receiver at a distance of 100 λ; by comparison, only 15.6% of a blackbody emitter reach a receiver in the same geometry. It is also shown that the emission achieved by a half MFE can lead to a photon recycling rate above 95% for below bandgap photons at an emitter-receiver separation of 100 λ. By applying a half MFE, the absolute TPV efficiency can be improved from 5.74% to 37.15%, which represents a significant step forward in realizing high-efficiency TPV systems.

Production of multicharged metal ion beams on the first stage of tandem-type ECRIS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hagino, Shogo, E-mail: hagino@nf.eie.eng.osaka-u.ac.jp; Nagaya, Tomoki; Nishiokada, Takuya

2016-02-15

Multicharged metal ion beams are required to be applied in a wide range of fields. We aim at synthesizing iron-endohedral fullerene by transporting iron ion beams from the first stage into the fullerene plasma in the second stage of the tandem-type electron cyclotron resonance ion source (ECRIS). We developed new evaporators by using a direct ohmic heating method and a radiation heating method from solid state pure metal materials. We investigate their properties in the test chamber and produce iron ions on the first stage of the tandem-type ECRIS. As a result, we were successful in extracting Fe{sup +} ionmore » beams from the first stage and introducing Fe{sup +} ion beams to the second stage. We will try synthesizing iron-endohedral fullerene on the tandem-type ECRIS by using these evaporators.« less

Investigating the possibility of a monitoring fast ion diagnostic for ITER.

PubMed

De Angelis, R; von Hellermann, M G; Orsitto, F P; Tugarinov, S

2008-10-01

In burning plasma fusion devices, fast ion transport plays a central role in the performances of the machines. Moreover the losses of energetic particles might cause severe damages on plasma facing components. Therefore real time measurements of fast ion transport would provide valuable information for safe and reliable plasma operations. In this paper, we examine the feasibility of a monitoring system based on active charge exchange recombination spectroscopy making use of the 0.5 MeV/amu ITER heating neutral beams for detecting fast (4)He(+2) (alphas) particles in ITER plasmas. There are two time scales relevant to fast ion dynamics: the first is the slowing down time of the distribution function which is of the order of 1 s, and the second is the time scale of burstlike transport events such as collective Alfven mode excitations, which--for typical ITER plasma parameters--can be as low as 0.2-1 ms. To detect such fast events a broadband high-throughput spectrometer is needed, while for the reconstruction of the alpha velocity distribution function a higher resolution spectrometer and longer integration time are necessary. To monitor a spatial redistribution of fast particles due to the propagation of the instability, it is proposed to use a limited number of spatial channels, looking at the charge exchange He II spectra induced by the heating beams, whose energy matches the slowing down energies of fast particles. The proposal is to share the motional stark effect periscope on equatorial port 3 [A. Malaquias et al., Rev. Sci. Instrum. 75, 3393 (2004)] adding additional fibers and suitable instruments. A signal to noise ratio of 5 could be achieved with a spatial resolution of a/15 and a time resolution of 5 ms, in a broad spectral band of 100 A, corresponding to the spectral broadening of the line emitted by alpha particles with energies DeltaE < or = 1.5 MeV. Fast H and D ion populations created by heating neutral beam or ion cyclotron resonance heating are expected to produce significantly lower charge exchange signal levels and can only be monitored on substantially longer time scales as it is expected because of the strong energy difference with respect to the heating neutral beam and the consequently low charge exchange cross sections.

Thermal diffusivity measurement in thin metallic filaments using the mirage method with multiple probe beams and a digital camera

NASA Astrophysics Data System (ADS)

Vargas, E.; Cifuentes, A.; Alvarado, S.; Cabrera, H.; Delgado, O.; Calderón, A.; Marín, E.

2018-02-01

Photothermal beam deflection is a well-established technique for measuring thermal diffusivity. In this technique, a pump laser beam generates temperature variations on the surface of the sample to be studied. These variations transfer heat to the surrounding medium, which may be air or any other fluid. The medium in turn experiences a change in the refractive index, which will be proportional to the temperature field on the sample surface when the distance to this surface is small. A probe laser beam will suffer a deflection due to the refractive index periodical changes, which is usually monitored by means of a quadrant photodetector or a similar device aided by lock-in amplification. A linear relationship that arises in this technique is that given by the phase lag of the thermal wave as a function of the distance to a punctual heat source when unidimensional heat diffusion can be guaranteed. This relationship is useful in the calculation of the sample's thermal diffusivity, which can be obtained straightforwardly by the so-called slope method, if the pump beam modulation frequency is well-known. The measurement procedure requires the experimenter to displace the probe beam at a given distance from the heat source, measure the phase lag at that offset, and repeat this for as many points as desired. This process can be quite lengthy in dependence of the number points. In this paper, we propose a detection scheme, which overcomes this limitation and simplifies the experimental setup using a digital camera that substitutes all detection hardware utilizing motion detection techniques and software digital signal lock-in post-processing. In this work, the method is demonstrated using thin metallic filaments as samples.

Thermal diffusivity measurement in thin metallic filaments using the mirage method with multiple probe beams and a digital camera.

PubMed

Vargas, E; Cifuentes, A; Alvarado, S; Cabrera, H; Delgado, O; Calderón, A; Marín, E

2018-02-01

Photothermal beam deflection is a well-established technique for measuring thermal diffusivity. In this technique, a pump laser beam generates temperature variations on the surface of the sample to be studied. These variations transfer heat to the surrounding medium, which may be air or any other fluid. The medium in turn experiences a change in the refractive index, which will be proportional to the temperature field on the sample surface when the distance to this surface is small. A probe laser beam will suffer a deflection due to the refractive index periodical changes, which is usually monitored by means of a quadrant photodetector or a similar device aided by lock-in amplification. A linear relationship that arises in this technique is that given by the phase lag of the thermal wave as a function of the distance to a punctual heat source when unidimensional heat diffusion can be guaranteed. This relationship is useful in the calculation of the sample's thermal diffusivity, which can be obtained straightforwardly by the so-called slope method, if the pump beam modulation frequency is well-known. The measurement procedure requires the experimenter to displace the probe beam at a given distance from the heat source, measure the phase lag at that offset, and repeat this for as many points as desired. This process can be quite lengthy in dependence of the number points. In this paper, we propose a detection scheme, which overcomes this limitation and simplifies the experimental setup using a digital camera that substitutes all detection hardware utilizing motion detection techniques and software digital signal lock-in post-processing. In this work, the method is demonstrated using thin metallic filaments as samples.

Second harmonic generation of q-Gaussian laser beam in preformed collisional plasma channel with nonlinear absorption

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gupta, Naveen, E-mail: naveens222@rediffmail.com; Singh, Arvinder, E-mail: arvinder6@lycos.com; Singh, Navpreet, E-mail: navpreet.nit@gmail.com

2015-11-15

This paper presents a scheme for second harmonic generation of an intense q-Gaussian laser beam in a preformed parabolic plasma channel, where collisional nonlinearity is operative with nonlinear absorption. Due to nonuniform irradiance of intensity along the wavefront of the laser beam, nonuniform Ohmic heating of plasma electrons takes place. Due to this nonuniform heating of plasma, the laser beam gets self-focused and produces strong density gradients in the transverse direction. The generated density gradients excite an electron plasma wave at pump frequency that interacts with the pump beam to produce its second harmonics. The formulation is based on amore » numerical solution of the nonlinear Schrodinger wave equation in WKB approximation followed by moment theory approach. A second order nonlinear differential equation governing the propagation dynamics of the laser beam with distance of propagation has been obtained and is solved numerically by Runge Kutta fourth order technique. The effect of nonlinear absorption on self-focusing of the laser beam and conversion efficiency of its second harmonics has been investigated.« less

During air cool process aerosol absorption detection with photothermal interferometry

NASA Astrophysics Data System (ADS)

Li, Baosheng; Xu, Limei; Huang, Junling; Ma, Fei; Wang, Yicheng; Li, Zhengqiang

2014-11-01

This paper studies the basic principle of laser photothermal interferometry method of aerosol particles absorption coefficient. The photothermal interferometry method with higher accuracy and lower uncertainty can directly measure the absorption coefficient of atmospheric aerosols and not be affected by scattered light. With Jones matrix expression, the math expression of a special polarization interferometer is described. This paper using folded Jamin interferometer, which overcomes the influence of vibration on measuring system. Interference come from light polarization beam with two orthogonal and then combine to one beam, finally aerosol absorption induced refractive index changes can be gotten with four beam of phase orthogonal light. These kinds of styles really improve the stability of system and resolution of the system. Four-channel detections interact with interference fringes, to reduce the light intensity `zero drift' effect on the system. In the laboratory, this device typical aerosol absorption index, it shows that the result completely agrees with actual value. After heated by laser, cool process of air also show the process of aerosol absorption. This kind of instrument will be used to monitor ambient aerosol absorption and suspended particulate matter chemical component. Keywords: Aerosol absorption coefficient; Photothermal interferometry; Suspended particulate matter.

Probing free jet expansions of supercritical fluids

NASA Astrophysics Data System (ADS)

Christen, W.; Rademann, K.

2009-10-01

Attempting to improve the comprehension of supersonic molecular beams at elevated pressures we present a comparative study of thermodynamic descriptions of the terminal flow velocity in free jet expansions. As model system we choose carbon dioxide due to its widespread utilization in supercritical fluid technology. Numerical results for the thermodynamic quantities are obtained using a high accuracy equation of state explicit in the Helmholtz free energy. The influence of pressure and temperature on the beam velocity is investigated for a broad range of stagnation conditions. A consistent physical picture is obtained for calculations employing the initial and final molar enthalpies, while enormous discrepancies are found for descriptions based on the molar isobaric heat capacity or the heat capacity ratio. The deviations are particularly pronounced at the gas-liquid phase transition and in the vicinity of the critical point and can be related to the diverse assumptions of ideal gas behavior. It is shown that computations using real fluid enthalpies permit to assess the fraction of condensation in supersonic jets.

Physics-based Control-oriented Modeling of the Current Profile Evolution in NSTX-Upgrade

NASA Astrophysics Data System (ADS)

Ilhan, Zeki; Barton, Justin; Shi, Wenyu; Schuster, Eugenio; Gates, David; Gerhardt, Stefan; Kolemen, Egemen; Menard, Jonathan

2013-10-01

The operational goals for the NSTX-Upgrade device include non-inductive sustainment of high- β plasmas, realization of the high performance equilibrium scenarios with neutral beam heating, and achievement of longer pulse durations. Active feedback control of the current profile is proposed to enable these goals. Motivated by the coupled, nonlinear, multivariable, distributed-parameter plasma dynamics, the first step towards feedback control design is the development of a physics-based, control-oriented model for the current profile evolution in response to non-inductive current drives and heating systems. For this purpose, the nonlinear magnetic-diffusion equation is coupled with empirical models for the electron density, electron temperature, and non-inductive current drives (neutral beams). The resulting first-principles-driven, control-oriented model is tailored for NSTX-U based on the PTRANSP predictions. Main objectives and possible challenges associated with the use of the developed model for control design are discussed. This work was supported by PPPL.

Influence of thermal deformation in cavity mirrors on beam propagation characteristics of high-power slab lasers

NASA Astrophysics Data System (ADS)

Wang, Zhen; Xiao, Longsheng; Wang, Wei; Wu, Chao; Tang, Xiahui

2018-01-01

Owing to their good diffusion cooling and low sensitivity to misalignment, slab-shape negative-branch unstable-waveguide resonators are widely used for high-power lasers in industry. As the output beam of the resonator is astigmatic, an external beam shaping system is required. However, the transverse dimension of the cavity mirrors in the resonator is large. For a long-time operation, the heating of cavity mirrors can be non-uniform. This results in micro-deformation and a change in the radius of curvature of the cavity mirrors, and leads to an output beam of an offset optical axis of the resonator. It was found that a change in the radius of curvature of 0.1% (1 mm) caused by thermal deformation generates a transverse displacement of 1.65 mm at the spatial filter of the external beam shaping system, and an output power loss of more than 80%. This can potentially burn out the spatial filter. In order to analyze the effect of the offset optical axis of the beam on the external optical path, we analyzed the transverse displacement and rotational misalignments of the spatial filter. For instance, if the transverse displacement was 0.3 mm, the loss in the output power was 9.6% and a sidelobe appeared in the unstable direction. If the angle of rotation was 5°, the loss in the output power was 2%, and the poles were in the direction of the waveguide. Based on these results, by adjusting the bending mirror, the deviation angle of the output beam of the resonator cavity was corrected, in order to obtain maximum output power and optimal beam quality. Finally, the propagation characteristics of the corrected output beam were analyzed.

Laser beam generating apparatus

DOEpatents

Warner, B.E.; Duncan, D.B.

1993-12-28

Laser beam generating apparatus including a septum segment disposed longitudinally within the tubular structure of the apparatus. The septum provides for radiatively dissipating heat buildup within the tubular structure and for generating relatively uniform laser beam pulses so as to minimize or eliminate radial pulse delays (the chevron effect). 11 figures.

Review of hydrodynamic tunneling issues in high power particle accelerators

NASA Astrophysics Data System (ADS)

Tahir, N. A.; Burkart, F.; Schmidt, R.; Shutov, A.; Piriz, A. R.

2018-07-01

Full impact of one Large Hadron Collider (LHC) 7 TeV proton beam on solid targets made of different materials including copper and carbon, was simulated using an energy deposition code, FLUKA and a two-dimensional hydrodynamic code, BIG2, iteratively. These studies showed that the penetration depth of the entire beam comprised of 2808 proton bunches significantly increases due to a phenomenon named hydrodynamic tunneling of the protons and the shower. For example, the static range of a single 7 TeV proton and its shower is about 1 m in solid copper, but the full LHC beam will penetrate up to about 35 m in the target, if the hydrodynamic effects were included. Due to the potential implications of this result on the machine protection considerations, it was decided to have an experimental verification of the hydrodynamic tunneling effect. For this purpose, experiments were carried out at the CERN HiRadMat (High Radiation to Materials) facility in which extended solid copper cylindrical targets were irradiated with the 440 GeV proton beam generated by the Super Proton Synchrotron (SPS). Simulations of beam-target heating considering the same beam parameters that were used in the experiments, were also performed. These experiments not only confirmed the existence of the hydrodynamic tunneling, but the experimental measurements showed very good agreement with the experimental results as well. This provided confidence in the work on LHC related beam-matter heating simulations. Currently, a design study is being carried out by the international community (with CERN taking the leading role) for a post LHC collider named, the Future Circular Collider (FCC) which will accelerate two counter rotating proton beams up to a particle energy of 50 TeV. Simulations of the full impact of one FCC beam comprised of 10,600 proton bunches with a solid copper target have also been done. These simulations have shown that although the static range of a single 50 TeV proton and its shower in solid copper is around 1.8 m, the entire beam will penetrate up to about 350 m in the target. Feasibility studies of developing a water beam dump for the FCC have also been carried out. A review of this work and its implications on machine protection system are presented in this paper.

Comparative study of beam losses and heat loads reduction methods in MITICA beam source

NASA Astrophysics Data System (ADS)

Sartori, E.; Agostinetti, P.; Dal Bello, S.; Marcuzzi, D.; Serianni, G.; Sonato, P.; Veltri, P.

2014-02-01

In negative ion electrostatic accelerators a considerable fraction of extracted ions is lost by collision processes causing efficiency loss and heat deposition over the components. Stripping is proportional to the local density of gas, which is steadily injected in the plasma source; its pumping from the extraction and acceleration stages is a key functionality for the prototype of the ITER Neutral Beam Injector, and it can be simulated with the 3D code AVOCADO. Different geometric solutions were tested aiming at the reduction of the gas density. The parameter space considered is limited by constraints given by optics, aiming, voltage holding, beam uniformity, and mechanical feasibility. The guidelines of the optimization process are presented together with the proposed solutions and the results of numerical simulations.

Thermal Imaging Applied to Cryocrystallography: Cryocooling and Beam Heating (Part I)

NASA Technical Reports Server (NTRS)

Snell, Edward; Bellamy, Henry; Rosenbaum, Gerd; vanderWoerd, Mark; Kazmierczak, Michael

2006-01-01

Thermal imaging provides a non-invasive method to study both the cryocooling process and the heating due to the X-ray beam interaction with a sample. The method has been used successfully to image cryocooling in a number of experimental situations, i.e. cooling as a function of sample volume and as a function of cryostream orientation. Although there are experimental limitations to the method, it has proved a powerful technique to aid cryocrystallography development. Due to the rapid spatial temperature information provided about the sample it is also a powerful tool in the testing of mathematical models. Recently thermal imaging has been used to measure the temperature distribution on both a model and typical crystal samples illuminated with an X-ray beam produced by an undulator. A brief overview of thermal imaging and previous results will be presented. In addition, a detailed description of the calibration and experimental aspects of the beam heating measurements will be described. This will complement the following talk on the mathematical modeling and analysis of the results.

Evolution and Control of 2219 Aluminum Microstructural Features Through Electron Beam Freeform Fabrication

NASA Technical Reports Server (NTRS)

Taminger, Karen M.; Hafley, Robert A.; Domack, Marcia S.

2006-01-01

The layer-additive nature of the electron beam freeform fabrication (EBF3) process results in a tortuous thermal path producing complex microstructures including: small homogeneous equiaxed grains; dendritic growth contained within larger grains; and/or pervasive dendritic formation in the interpass regions of the deposits. Several process control variables contribute to the formation of these different microstructures, including translation speed, wire feed rate, beam current and accelerating voltage. In electron beam processing, higher accelerating voltages embed the energy deeper below the surface of the substrate. Two EBF3 systems have been established at NASA Langley, one with a low-voltage (10-30kV) and the other a high-voltage (30-60 kV) electron beam gun. Aluminum alloy 2219 was processed over a range of different variables to explore the design space and correlate the resultant microstructures with the processing parameters. This report is specifically exploring the impact of accelerating voltage. Of particular interest is correlating energy to the resultant material characteristics to determine the potential of achieving microstructural control through precise management of the heat flux and cooling rates during deposition.

A high repetition rate transverse beam profile diagnostic for laser-plasma proton sources

NASA Astrophysics Data System (ADS)

Dover, Nicholas; Nishiuchi, Mamiko; Sakaki, Hironao; Kando, Masaki; Nishitani, Keita

2016-10-01

The recently upgraded J-KAREN-P laser can provide PW peak power and intensities approaching 1022 Wcm-2 at 0.1 Hz. Scaling of sheath acceleration to such high intensities predicts generation of protons to near 100 MeV, but changes in electron heating mechanisms may affect the emitted proton beam properties, such as divergence and pointing. High repetition rate simultaneous measurement of the transverse proton distribution and energy spectrum are therefore key to understanding and optimising the source. Recently plastic scintillators have been used to measure online proton beam transverse profiles, removing the need for time consuming post-processing. We are therefore developing a scintillator based transverse proton beam profile diagnostic for use in ion acceleration experiments using the J-KAREN-P laser. Differential filtering provides a coarse energy spectrum measurement, and time-gating allows differentiation of protons from other radiation. We will discuss the design and implementation of the diagnostic, as well as proof-of-principle results from initial experiments on the J-KAREN-P system demonstrating the measurement of sheath accelerated proton beams up to 20 MeV.

Scientific program and abstracts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gerich, C.

1983-01-01

The Fifth International Conference on High-Power Particle Beams is organized jointly by the Lawrence Livermore National Laboratory and Physics International Company. As in the previous conferences in this series, the program includes the following topics: high-power, electron- and ion-beam acceleration and transport; diode physics; high-power particle beam interaction with plasmas and dense targets; particle beam fusion (inertial confinement); collective ion acceleration; particle beam heating of magnetically confined plasmas; and generation of microwave/free-electron lasers.

Method and apparatus for reducing coherence of high-power laser beams

DOEpatents

Moncur, Norman K.; Mayer, Frederick J.

1978-01-01

Method and apparatus for reducing the coherence and for smoothing the power density profile of a collimated high-power laser beam in which the beam is focused at a point on the surface of a target fabricated of material having a low atomic number. The initial portion of the focused beam heats the material to form a hot reflective plasma at the material surface. The remaining, major portion of the focused beam is reflected by the plasma and recollected to form a collimated beam having reduced beam coherence.

Mineralogy of the Hydrous Lower Mantle

NASA Astrophysics Data System (ADS)

Shim, S. H.; Chen, H.; Leinenweber, K. D.; Kunz, M.; Prakapenka, V.; Bechtel, H.; Liu, Z.

2017-12-01

The hydrous ringwoodite inclusions found in diamonds suggest water storage in the mantle transition zone. However, water storage in the lower mantle remains unclear. Bridgmanite and magnesiowustite appear to have very little storage capacity for water. Here, we report experimental results indicating significant changes in the lower-mantle mineralogy under the presence of water. We have synthesized Mg2SiO4 ringwoodite with 2 wt% water in multi-anvil press at 20 GPa and 1573 K at ASU. The hydrous ringwoodite sample was then loaded to diamond anvil cells with Ar or Ne as a pressure medium. We heated the pure hydrous ringwoodite samples at lower-mantle pressure using a CO2 laser heating system at ASU. We measured X-ray diffraction patterns at the GSECARS sector of the Advanced Photon Source (APS) and 12.2.2 sector of the Advanced Light Source (ALS). For the separate Pt-mixed samples, we have conducted in situ heating at the beamlines using near IR laser heating systems. We measured the infrared spectra of the heated samples at high pressure and after pressure quench at 1.4.4 sector of ALS. In the in situ experiments with hydrous ringwoodite + Pt mixture as a starting material, we found formation of stishovite together with bridgmanite and periclase during heating with a near IR laser beams at 1300-2500 K and 35-66 GPa. However, some hydrous ringwoodite still remains even after a total of 45 min of heating. In contrast, the hydrous ringwoodite samples heated without Pt by CO2 laser beams are transformed completely to bridgmanite, periclase and stishovite at 31-55 GPa and 1600-1900 K. We have detected IR active OH mode of stishovite from the samples heated at lower-mantle pressures. The unit-cell volume of stishovite measured after pressure quench is greater than that of dry stishovite by 0.3-0.6%, supporting 0.5-1 wt% of H2O in stishovite in these samples. Stishovite is a thermodynamically forbidden phase in the dry lower mantle because of the existence of periclase and bridgmanite. However, our results indicate that stishovite can exist together with periclase and bridgmanite when water is present, because water is stored in stishovite. Therefore, water-rich parts of the lower mantle, such as regions with subducting slabs, would have distinct mineralogy from their dry counterparts, containing stishovite as a water storage mineral.

Analyses of the reflector tank, cold source, and beam tube cooling for ANS reactor. [Advanced Neutron Source (ANS)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marland, S.

1992-07-01

This report describes my work as an intern with Martin Marietta Energy Systems, Inc., in the summer of 1991. I was assigned to the Reactor Technology Engineering Department, working on the Advanced Neutron Source (ANS). My first project was to select and analyze sealing systems for the top of the diverter/reflector tank. This involved investigating various metal seals and calculating the forces necessary to maintain an adequate seal. The force calculations led to an analysis of several bolt patterns and lockring concepts that could be used to maintain a seal on the vessel. Another project involved some pressure vessel stressmore » calculations and the calculation of the center of gravity for the cold source assembly. I also completed some sketches of possible cooling channel patterns for the inner vessel of the cold source. In addition, I worked on some thermal design analyses for the reflector tank and beam tubes, including heat transfer calculations and assisting in Patran and Pthermal analyses. To supplement the ANS work, I worked on other projects. I completed some stress/deflection analyses on several different beams. These analyses were done with the aid of CAASE, a beam-analysis software package. An additional project involved bending analysis on a carbon removal system. This study was done to find the deflection of a complex-shaped beam when loaded with a full waste can.« less

New evaporator station for the center for accelerator target science

NASA Astrophysics Data System (ADS)

Greene, John P.; Labib, Mina

2018-05-01

As part of an equipment grant provided by DOE-NP for the Center for Accelerator Target Science (CATS) initiative, the procurement of a new, electron beam, high-vacuum deposition system was identified as a priority to insure reliable and continued availability of high-purity targets. The apparatus is designed to contain TWO electron beam guns; a standard 4-pocket 270° geometry source as well as an electron bombardment source. The acquisition of this new system allows for the replacement of TWO outdated and aging vacuum evaporators. Also included is an additional thermal boat source, enhancing our capability within this deposition unit. Recommended specifications for this system included an automated, high-vacuum pumping station, a deposition chamber with a rotating and heated substrate holder for uniform coating capabilities and incorporating computer-controlled state-of-the-art thin film technologies. Design specifications, enhanced capabilities and the necessary mechanical modifications for our target work are discussed.

High power linear pulsed beam annealer

DOEpatents

Strathman, Michael D.; Sadana, Devendra K.; True, Richard B.

1983-01-01

A high power pulsed electron beam is produced in a system comprised of an electron gun having a heated cathode, control grid, focus ring, and a curved drift tube. The drift tube is maintained at a high positive voltage with respect to the cathode to accelerate electrons passing through the focus ring and to thereby eliminate space charge. A coil surrounding the curved drift tube provides a magnetic field which maintains the electron beam focused about the axis of the tube and imparts motion on electrons in a spiral path for shallow penetration of the electrons into a target. The curvature of the tube is selected so there is no line of sight between the cathode and a target holder positioned within a second drift tube spaced coaxially from the curved tube. The second tube and the target holder are maintained at a reference voltage that decelerates the electrons. A second coil surrounding the second drift tube maintains the electron beam focused about the axis of the second drift tube and compresses the electron beam to the area of the target. The target holder can be adjusted to position the target where the cross section of the beam matches the area of the target.

Laser beam generating apparatus

DOEpatents

Warner, B.E.; Duncan, D.B.

1994-02-15

Laser beam generating apparatus including a septum segment disposed longitudinally within the tubular structure of the apparatus is described. The septum provides for radiatively dissipating heat buildup within the tubular structure and for generating relatively uniform laser beam pulses so as to minimize or eliminate radial pulse delays (the chevron effect). 7 figures.

Portable Electron-Beam Free-Form Fabrication System

NASA Technical Reports Server (NTRS)

Watson, J. Kevin; Petersen, Daniel D.; Taminger, Karen M.; Hafley, Robert A.

2005-01-01

A portable electron-beam free-form fabrication (EB F3) system, now undergoing development, is intended to afford a capability for manufacturing metal parts in nearly net sizes and shapes. Although the development effort is oriented toward the eventual use of systems like this one to supply spare metal parts aboard spacecraft in flight, the basic system design could also be adapted to terrestrial applications in which there are requirements to supply spare parts on demand at locations remote from warehouses and conventional manufacturing facilities. Prior systems that have been considered for satisfying the same requirements (including prior free-form fabrication systems) are not easily portable because of their bulk and massive size. The mechanical properties of the components that such systems produce are often inferior to the mechanical properties of the corresponding original, conventionally fabricated components. In addition, the prior systems are not efficient in the utilization of energy and of feedstock. In contrast, the present developmental system is designed to be sufficiently compact and lightweight to be easily portable, to utilize both energy and material more efficiently, and to produce components that have mechanical properties approximating those of the corresponding original components. The developmental EB F3 system will include a vacuum chamber and associated vacuum pumps, an electron-beam gun and an associated power supply, a multiaxis positioning subsystem, a precise wire feeder, and an instrumentation system for monitoring and control. The electron-beam gun, positioning subsystem, and wire feeder will be located inside the vacuum chamber (see figure). The electron beam gun and the wire feeder will be mounted in fixed positions inside the domed upper portion of the vacuum chamber. The positioning subsystem and ports for the vacuum pumps will be located on a base that could be dropped down to provide full access to the interior of the chamber when not under vacuum. During operation, wire will be fed to a fixed location, entering the melted pool created by the electron beam. Heated by the electron beam, the wire will melt and fuse to either the substrate or with the previously deposited metal wire fused on top of the positioning table. Based on a computer aided design (CAD) model and controlled by a computer, the positioning subsystem

Phase I Development of Neutral Beam Injector Solid-State Power System

NASA Astrophysics Data System (ADS)

Prager, James; Ziemba, Timothy; Miller, Kenneth E.; Slobodov, Ilia; Anderson, Seth

2017-10-01

Neutral beam injection (NBI) is an important tool for plasma heating, current drive and a diagnostic at fusion science experiments around the United States, including tokamaks, validation platform experiments, and privately funded fusion concepts. Currently, there are no vendors in the United States for NBI power systems. Eagle Harbor Technologies (EHT), Inc. is developing a new power system for NBI that takes advantage of the latest developments in solid-state switching. EHT has developed a resonant converter that can be scaled to the power levels required for NBI at small-scale validation platform experiments like the Lithium Tokamak Experiment. This power system can be used to modulate the NBI voltages over the course of a plasma shot, which can lead to improved control over the plasma. EHT will present initial modeling used to design this system as well as experimental data showing operation at 15 kV and 40 A for 10 ms into a test load. With support of DOE SBIR.

A high-sensitivity tunable two-beam fiber-coupled high-density magnetometer with laser heating

DOE PAGES

Savukov, Igor Mykhaylovich; Boshier, Malcolm Geoffrey

2016-10-13

Atomic magnetometers (AM) are finding many applications in biomagnetism, national security, industry, and science. Fiber-coupled (FC) designs promise to make them compact and flexible for operation. Most FC designs are based on a single-beam configuration or electrical heating. Here, we demonstrate a two-beam FC AM with laser heating that has 5 fT/Hz 1/2 sensitivity at low frequency (50 Hz), which is higher than that of other fiber-coupled magnetometers and can be improved to the sub-femtotesla level. Here, this magnetometer is widely tunable from DC to very high frequencies (as high as 100 MHz; the only issue might be the applicationmore » of a suitable uniform and stable bias field) with a sensitivity under 10 fT/Hz 1/2 and can be used for magneto-encephalography (MEG), magneto-cardiography (MCG), underground communication, ultra-low MRI/NMR, NQR detection, and other applications.« less

A High-Sensitivity Tunable Two-Beam Fiber-Coupled High-Density Magnetometer with Laser Heating

PubMed Central

Savukov, Igor; Boshier, Malcolm G.

2016-01-01

Atomic magnetometers (AM) are finding many applications in biomagnetism, national security, industry, and science. Fiber-coupled (FC) designs promise to make them compact and flexible for operation. Most FC designs are based on a single-beam configuration or electrical heating. Here, we demonstrate a two-beam FC AM with laser heating that has 5 fT/Hz1/2 sensitivity at low frequency (50 Hz), which is higher than that of other fiber-coupled magnetometers and can be improved to the sub-femtotesla level. This magnetometer is widely tunable from DC to very high frequencies (as high as 100 MHz; the only issue might be the application of a suitable uniform and stable bias field) with a sensitivity under 10 fT/Hz1/2 and can be used for magneto-encephalography (MEG), magneto-cardiography (MCG), underground communication, ultra-low MRI/NMR, NQR detection, and other applications. PMID:27754358

Achievement and improvement of the JT-60U negative ion source for JT-60 Super Advanced (invited)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kojima, A.; Hanada, M.; Tanaka, Y.

2010-02-15

Developments of the large negative ion source have been progressed in the high-energy, high-power, and long-pulse neutral beam injector for JT-60 Super Advanced. Countermeasures have been studied and tested for critical issues of grid heat load and voltage holding capability. As for the heat load of the acceleration grids, direct interception of D{sup -} ions was reduced by adjusting the beamlet steering. As a result, the heat load was reduced below an allowable level for long-pulse injections. As for the voltage holding capability, local electric field was mitigated by tuning gap lengths between large-area acceleration grids in the accelerator. Asmore » a result, the voltage holding capability was improved up to the rated value of 500 kV. To investigate the voltage holding capability during beam acceleration, the beam acceleration test is ongoing with new extended gap.« less

Mechanical energy flow models of rods and beams

NASA Technical Reports Server (NTRS)

Wohlever, J. C.; Bernhard, R. J.

1992-01-01

It has been proposed that the flow of mechanical energy through a structural/acoustic system may be modeled in a manner similar to that of flow of thermal energy/in a heat conduction problem. If this hypothesis is true, it would result in relatively efficient numerical models of structure-borne energy in large built-up structures. Fewer parameters are required to approximate the energy solution than are required to model the characteristic wave behavior of structural vibration by using traditional displacement formulations. The energy flow hypothesis is tested in this investigation for both longitudinal vibration in rods and transverse flexural vibrations of beams. The rod is shown to behave approximately according to the thermal energy flow analogy. However, the beam solutions behave significantly differently than predicted by the thermal analogy unless locally-space-averaged energy and power are considered. Several techniques for coupling dissimilar rods and beams are also discussed. Illustrations of the solution accuracy of the methods are included.

Apparatus and method for quantitative measurement of small differences in optical absorptivity between two samples using differential interferometry and the thermooptic effect

DOEpatents

Cremers, David A.; Keller, Richard A.

1984-01-01

An apparatus and method for the measurement of small differences in optical absorptivity of weakly absorbing solutions using differential interferometry and the thermooptic effect has been developed. Two sample cells are placed in each arm of an interferometer and are traversed by colinear probe and heating laser beams. The interrogation probe beams are recombined forming a fringe pattern, the intensity of which can be related to changes in optical pathlength of these laser beams through the cells. This in turn can be related to small differences in optical absorptivity which results in different amounts of sample heating when the heating laser beams are turned on, by the fact that the index of refraction of a liquid is temperature dependent. A critical feature of this invention is the stabilization of the optical path of the probe beams against drift. Background (solvent) absorption can then be suppressed by a factor of approximately 400. Solute absorptivities of about 10.sup.-5 cm.sup.-1 can then be determined in the presence of background absorptions in excess of 10.sup.-3 cm.sup.-1. In addition, the smallest absorption measured with the instant apparatus and method is about 5.times. 10.sup.-6 cm.sup.-1.

Apparatus and method for quantitative measurement of small differences in optical absorptivity between two samples using differential interferometry and the thermooptic effect

DOEpatents

Cremers, D.A.; Keller, R.A.

1982-06-08

An apparatus and method for the measurement of small differences in optical absorptivity of weakly absorbing solutions using differential interferometry and the thermooptic effect has been developed. Two sample cells are placed in each arm of an interferometer and are traversed by colinear probe and heating laser beams. The interrogation probe beams are recombined forming a fringe pattern, the intensity of which can be related to changes in optical pathlength of these laser beams through the cells. This in turn can be related to small differences in optical absorptivity which results in different amounts of sample heating when the heating laser beams are turned on, by the fact that the index of refraction of a liquid is temperature dependent. A critical feature of this invention is the stabilization of the optical path of the probe beams against drift. Background (solvent) absorption can then be suppressed by a factor of approximately 400. Solute absorptivities of about 10/sup -5/ cm/sup -1/ can then be determined in the presence of background absorptions in excess of 10/sup -3/ cm/sup -1/. In addition, the smallest absorption measured with the instant apparatus and method is about 5 x 10/sup -6/ cm/sup -1/.

Isochoric heating of solid gold targets with the PW-laser-driven ion beams (Conference Presentation)

NASA Astrophysics Data System (ADS)

Steinke, Sven; Ji, Qing; Bulanov, Stepan S.; Barnard, John; Vincenti, Henri; Schenkel, Thomas; Esarey, Eric H.; Leemans, Wim P.

2017-05-01

We present first results on ion acceleration with the BELLA PW laser as well as end-to-end simulation for isochoric heating of solid gold targets using PW-laser generated ion beams: (i) 2D Particle-In-Cell (PIC) simulations are applied to study the ion source characteristics of the PW laser-target interaction at the long focal length (f/65) beamline at laser intensities of ˜[5×10]^19 Wcm-2 at spot size of 0=53 μm on a CH target. (ii) In order to transport the ion beams to an EMP-free environment, an active plasma lens will be used. This was modeled [1] by calculating the Twiss parameters of the ion beam from the appropriate transport matrixes taking the source parameters obtained from the PIC simulation. (iii) Hydrodynamic simulations indicate that these ion beams can isochorically heat a 1 mm3 gold target to the Warm Dense Matter state. Reference: J. van Tilborg et al, Phys. Rev. Lett. 115, 184802 (2015). This work was supported by Laboratory Directed Research and Development (LDRD) funding from Lawrence Berkeley National Laboratory, provided by the Director, Office of Science, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.

Progress on the superconducting undulator for ANKA and on the instrumentation for R and D

DOE Office of Scientific and Technical Information (OSTI.GOV)

Casalbuoni, Sara; Baumbach, Tilo; Grau, Andreas

2010-06-23

Superconducting undulators show a larger magnetic field strength for the same gap and period length, as compared to permanent magnet devices, which allows to generate X-ray beams of higher brilliance and with harder spectrum. The worldwide first short period length superconducting undulator is in operation since 2005 at the synchrotron light source ANKA in Karlsruhe [1]. To further drive the development in this field a research and development program is being carried out. In this contribution we report on the last progress of the construction of a 1.5 m long superconducting undulator with a period length of 15 mm, plannedmore » to be installed in ANKA beginning 2010 to be the light source of the new beamline NANO for high resolution X-ray scattering. The key specifications of the system are an undulator parameter K higher than 2 (with a magnetic gap of 5 mm) and a phase error smaller than 3.5 degrees. Cryocoolers will keep the coils at 4.2 K for a beam heat load of 4 W. The ongoing R and D includes improvements in understanding of the magnetic field properties and of the beam heat load mechanisms. The tools and instruments under development to fulfill these tasks are also discussed.« less

Progress on the superconducting undulator for ANKA and on the instrumentation for R&D

NASA Astrophysics Data System (ADS)

Casalbuoni, Sara; Baumbach, Tilo; Grau, Andreas; Hagelstein, Michael; de Jauregui, David Saez; Boffo, Cristian; Borlein, Markus; Walter, Wolfgang; Magerl, Andreas; Mashkina, Elena; Vassiljev, Nikita

2010-06-01

Superconducting undulators show a larger magnetic field strength for the same gap and period length, as compared to permanent magnet devices, which allows to generate X-ray beams of higher brilliance and with harder spectrum. The worldwide first short period length superconducting undulator is in operation since 2005 at the synchrotron light source ANKA in Karlsruhe [1]. To further drive the development in this field a research and development program is being carried out. In this contribution we report on the last progress of the construction of a 1.5 m long superconducting undulator with a period length of 15 mm, planned to be installed in ANKA beginning 2010 to be the light source of the new beamline NANO for high resolution X-ray scattering. The key specifications of the system are an undulator parameter K higher than 2 (with a magnetic gap of 5 mm) and a phase error smaller than 3.5 degrees. Cryocoolers will keep the coils at 4.2 K for a beam heat load of 4 W. The ongoing R&D includes improvements in understanding of the magnetic field properties and of the beam heat load mechanisms. The tools and instruments under development to fulfill these tasks are also discussed.

Comparison of PA imaging by narrow beam scanning and one-shot broad beam excitation

NASA Astrophysics Data System (ADS)

Xia, Jinjun; Wei, Chen-Wei; Huang, Lingyun; Pelivanov, I. M.; O'Donnell, Matthew

2011-03-01

Current systems designed for deep photoacoustic (PA) imaging typically use a low repetition rate, high power pulsed laser to provide a ns-scale pulse illuminating a large tissue volume. Acoustic signals recorded on each laser firing can be used to reconstruct a complete 2-D (3-D) image of sources of heat release within that region. Using broad-beam excitation, the maximum frame rate of the imaging system is restricted by the pulse repetition rate of the laser. An alternate illumination approach is proposed based on fast scanning by a low energy (~ 1 mJ) high repetition rate (up to a few kHz) narrow laser beam (~1 mm) along the tissue surface over a region of interest. A final PA image is produced from the summation of individual PA images reconstructed at each laser beam position. This concept can take advantage of high repetition rate fiber lasers to create PA images with much higher frame rates than current systems, enabling true real-time integration of photoacoustics with ultrasound imaging. As an initial proof of concept, we compare conventional broad beam illumination to a scanned beam approach in a simple model system. Two transparent teflon tubes with diameters of 1.6 mm and 0.8 mm were filled with ink having an absorption coefficient of 5 cm-1. These tubes were buried inside chicken breast tissue acting as an optical scattering medium. They were separated by 3 mm or 10 mm to test spatial and contrast resolution for the two scan formats. The excitation wavelength was 700 nm. The excitation source is a traditional OPO pumped by a Q-switched Nd:YAG laser with doubler. Photoacoustic images were reconstructed using signals from a small, scanned PVDF transducer acting as an acoustic array. Two different illumination schemes were compared: one was 15 mm x 10 mm in cross section and acted as the broad beam; the other was 5 mm x 2 mm in cross section (15 times smaller than the broad beam case) and was scanned over an area equivalent to broad beam illumination. Multiple images obtained during narrow beam scanning were added together to form one PA image equivalent to the single-shot broad beam one. Results of the phantom study indicate that PA images formed by narrow beam scanning excitation can be equivalent to one shot broad beam illumination in signal to noise ratio and spatial resolution. Future studies will focus on high repetition-rate laser sources and scan formats appropriate for real-time, integrated deep photoacoustic/ultrasonic imaging.

GMTIFS: the adaptive optics beam steering mirror for the GMT integral-field spectrograph

NASA Astrophysics Data System (ADS)

Davies, J.; Bloxham, G.; Boz, R.; Bundy, D.; Espeland, B.; Fordham, B.; Hart, J.; Herrald, N.; Nielsen, J.; Sharp, R.; Vaccarella, A.; Vest, C.; Young, P. J.

2016-07-01

To achieve the high adaptive optics sky coverage necessary to allow the GMT Integral-Field Spectrograph (GMTIFS) to access key scientific targets, the on-instrument adaptive-optics wavefront-sensing (OIWFS) system must patrol the full 180 arcsecond diameter guide field passed to the instrument. The OIWFS uses a diffraction limited guide star as the fundamental pointing reference for the instrument. During an observation the offset between the science target and the guide star will change due to sources such as flexure, differential refraction and non-sidereal tracking rates. GMTIFS uses a beam steering mirror to set the initial offset between science target and guide star and also to correct for changes in offset. In order to reduce image motion from beam steering errors to those comparable to the AO system in the most stringent case, the beam steering mirror is set a requirement of less than 1 milliarcsecond RMS. This corresponds to a dynamic range for both actuators and sensors of better than 1/180,000. The GMTIFS beam steering mirror uses piezo-walk actuators and a combination of eddy current sensors and interferometric sensors to achieve this dynamic range and control. While the sensors are rated for cryogenic operation, the actuators are not. We report on the results of prototype testing of single actuators, with the sensors, on the bench and in a cryogenic environment. Specific failures of the system are explained and suspected reasons for them. A modified test jig is used to investigate the option of heating the actuator and we report the improved results. In addition to individual component testing, we built and tested a complete beam steering mirror assembly. Testing was conducted with a point source microscope, however controlling environmental conditions to less than 1 micron was challenging. The assembly testing investigated acquisition accuracy and if there was any un-sensed hysteresis in the system. Finally we present the revised beam steering mirror design based on the outcomes and lessons learnt from this prototyping.

Negative ion source development for a photoneutralization based neutral beam system for future fusion reactors

NASA Astrophysics Data System (ADS)

Simonin, A.; Agnello, R.; Bechu, S.; Bernard, J. M.; Blondel, C.; Boeuf, J. P.; Bresteau, D.; Cartry, G.; Chaibi, W.; Drag, C.; Duval, B. P.; de Esch, H. P. L.; Fubiani, G.; Furno, I.; Grand, C.; Guittienne, Ph; Howling, A.; Jacquier, R.; Marini, C.; Morgal, I.

2016-12-01

In parallel to the developments dedicated to the ITER neutral beam (NB) system, CEA-IRFM with laboratories in France and Switzerland are studying the feasibility of a new generation of NB system able to provide heating and current drive for the future DEMOnstration fusion reactor. For the steady-state scenario, the NB system will have to provide a high NB power level with a high wall-plug efficiency (η ˜ 60%). Neutralization of the energetic negative ions by photodetachment (so called photoneutralization), if feasible, appears to be the ideal solution to meet these performances, in the sense that it could offer a high beam neutralization rate (>80%) and a wall-plug efficiency higher than 60%. The main challenge of this new injector concept is the achievement of a very high power photon flux which could be provided by 3 MW Fabry-Perot optical cavities implanted along the 1 MeV D- beam in the neutralizer stage. The beamline topology is tall and narrow to provide laminar ion beam sheets, which will be entirely illuminated by the intra-cavity photon beams propagating along the vertical axis. The paper describes the present R&D (experiments and modelling) addressing the development of a new ion source concept (Cybele source) which is based on a magnetized plasma column. Parametric studies of the source are performed using Langmuir probes in order to characterize and compare the plasma parameters in the source column with different plasma generators, such as filamented cathodes, radio-frequency driver and a helicon antenna specifically developed at SPC-EPFL satisfying the requirements for the Cybele (axial magnetic field of 10 mT, source operating pressure: 0.3 Pa in hydrogen or deuterium). The paper compares the performances of the three plasma generators. It is shown that the helicon plasma generator is a very promising candidate to provide an intense and uniform negative ion beam sheet.

X-ray monochromators for high-power synchrotron radiation sources

NASA Astrophysics Data System (ADS)

Hart, Michael

1990-11-01

Exact solutions to the problems of power flow from a line source of heat into a semicylinder and of uniform heat flow normal to a flat surface are discussed. These lead to bounds on feasible designs and the boundary layer problem can be placed in proper perspective. While finite element calculations are useful if the sample boundaries are predefined, they are much less help in establishing design principles. Previous work on hot beam X-ray crystal optics has emphasised the importance of coolant hydraulics and boundary layer heat transfer. Instead this paper emphasises the importance of the elastic response of crystals to thermal strainfields and the importance of maintaining the Darwin reflectivity. The conclusions of this design study are that the diffracting crystal region should be thin, but not very thin, similar in area to the hot beam footprint, part of a thin-walked buckling crystal box and remote from the support to which the crystal is rigidly clamped. Prototype 111 and 220 cooled silicon crystals tested at the National Synchrotron Light Source at Brookhaven have almost perfect rocking curves under a beam heat load of {1}/{3}kW.

Acoustically Enhanced Electroplating Being Developed

NASA Technical Reports Server (NTRS)

Oeftering, Richard C.

2002-01-01

In cooperation with the NASA Glenn Research Center, Alchemitron Corp. is developing the Acoustically Enhanced Electroplating Process (AEEP), a new technique of employing nonlinear ultrasonics to enhance electroplating. The applications range from electroplating full-panel electronic circuit boards to electroplating microelectronics and microelectromechanical systems (MEMS) devices. In a conventional plating process, the surface area to be plated is separated from the nonplated areas by a temporary mask. The mask may take many forms, from a cured liquid coating to a simple tape. Generally, the mask is discarded when the plating is complete, creating a solid waste product that is often an environmental hazard. The labor and materials involved with the layout, fabrication, and tooling of masks is a primary source of recurring and nonrecurring production costs. The objective of this joint effort, therefore, is to reduce or eliminate the need for masks. AEEP improves selective plating processes by using directed beams of high-intensity acoustic waves to create nonlinear effects that alter the fluid dynamic and thermodynamic behavior of the plating process. It relies on two effects: acoustic streaming and acoustic heating. Acoustic streaming is observed when a high-intensity acoustic beam creates a liquid current within the beam. The liquid current can be directed as the beam is directed and, thus, users can move liquid around as desired without using pumps and nozzles. The current of the electroplating electrolyte, therefore, can be directed at distinct target areas where electroplating is desired. The current delivers fresh electrolyte to the target area while flushing away the spent electrolyte. This dramatically increases the plating rate in the target area. In addition, acoustic heating of both the liquid in the beam and the target surface increases the chemical reaction rate, which further increases the plating rate. The combined effects of acoustic streaming and heating accelerate the deposition of plating in that area and, thus, provide an effect similar to a mask but without the costs of masking. AEEP further improves the plating process by clearing debris and bubbles from the surface by acoustic radiation pressure and acoustic streaming.

A New Kind of Curing

NASA Technical Reports Server (NTRS)

2001-01-01

A new curing method using automated tape placement (ATP) with electron beam (EB), or e-beam, produces a combination known as in situ e-beam curing. Through a Small Business Innovation Research (SBIR) contract from NASA's Marshall Space Flight Center, Science Research Laboratory, Inc., created the in situ e-beam curing technique, which uses a low-energy electron beam gun to cure various composite materials. One important benefit is the technique's utilization of room temperature curing, which lessens the chance of mismatching the thermal expansion coefficients of different materials. For instance, metals and composites will expand at different rates when heated, but the low-energy e-beam gun reduces the expansion differential. Using a low-energy gun also results in less x-ray shielding, significantly reduced capital costs, reduced facility space, and increased processing capabilities for larger parts. However, using a low-energy gun also means that each tape layer is treated individually because the gun can penetrate only one layer at a time. The e-beam gun emits lower energy x-rays, which are more easily shielded than those emitted by previous guns. The low-energy system is relatively portable due to its light weight and small size. The gun weighs about 70 pounds and can be easily mounted on a robotic arm or an ATP head.

Laser Heating of the Core-Shell Nanowires

NASA Astrophysics Data System (ADS)

Astefanoaei, Iordana; Dumitru, Ioan; Stancu, Alexandru

2016-12-01

The induced thermal stress in a heating process is an important parameter to be known and controlled in the magnetization process of core-shell nanowires. This paper analyses the stress produced by a laser heating source placed at one end of a core-shell type structure. The thermal field was computed with the non-Fourier heat transport equation using a finite element method (FEM) implemented in Comsol Multiphysics. The internal stresses are essentially due to thermal gradients and different expansion characteristics of core and shell materials. The stress values were computed using the thermo elastic formalism and are depending on the laser beam parameters (spot size, power etc.) and system characteristics (dimensions, thermal characteristics). Stresses in the GPa range were estimated and consequently we find that the magnetic state of the system can be influenced significantly. A shell material as the glass which is a good thermal insulator induces in the magnetic core, the smaller stresses and consequently the smaller magnetoelastic energy. These results lead to a better understanding of the switching process in the magnetic materials.

Ion-beam doping of GaAs with low-energy (100 eV) C(+) using combined ion-beam and molecular-beam epitaxy

NASA Astrophysics Data System (ADS)

Lida, Tsutomu; Makita, Yunosuke; Kimura, Shinji; Winter, Stefan; Yamada, Akimasa; Fons, Paul; Uekusa, Shin-Ichiro

1995-01-01

A combined ion-beam and molecular-beam-epitaxy (CIBMBE) system has been developed. This system consists of an ion implanter capable of producing ions in the energy range of 30 eV - 30 keV and conventional solid-source MBE. As a successful application of CIBMBE, low-energy (100 eV) carbon ion (C(+)) irradiation during MBE growth of GaAs was carried out at substrate temperatures T(sub g) between 500 and 590 C. C(+)-doped layers were characterized by low-temperature (2 K) photoluminescence (PL), Raman scattering, and van der Pauw measurements. PL spectra of undoped GaAs grown by CIBMBE revealed that unintentional impurity incorporation into the epilayer is extremely small and precise doping effects are observable. C(sub As) acceptor-related emissions such as 'g', (g-g), and (g-g)(sub beta) are observed and their spectra are significantly changed with increasing C(+) beam current density I(sub c). PL measurements showed that C atoms were efficiently incorporated during MBE growth by CIBMBE and were optically well activated as an acceptor in the as-grown condition even for T(sub g) as low as 500 C. Raman measurement showed negligible lattice damage of the epilayer bombarded with 100 eV C(+) with no subsequent heat treatment. These results indicate that contamination- and damage-free impurity doping without postgrowth annealing can be achieved by the CIBMBE method.

Aerosol Beam Focused-Laser Induced Plasma Spectrometer (ABF-LIPS) Continuous Emissions Multi-Metals Analyzer

DTIC Science & Technology

2012-06-01

heating are possible, but will add to system cost. 6.5 LESSONS LEARNED Reliable spiking of the airstream with metals proved to be a challenge . Based on...designed to allow calibration of the CEMS by use of standard solutions, filters, etc that challenge the pollutant analyzer part of the CEMS (and as much...of the whole system as possible), but which do not challenge the entire CEMS, including the sampling interface. Satisfactory response of the entire

A second-order theory for transverse ion heating and momentum coupling due to electrostatic ion cyclotron waves

NASA Technical Reports Server (NTRS)

Miller, Ronald H.; Winske, Dan; Gary, S. P.

1992-01-01

A second-order theory for electrostatic instabilities driven by counterstreaming ion beams is developed which describes momentum coupling and heating of the plasma via wave-particle interactions. Exchange rates between the waves and particles are derived, which are suitable for the fluid equations simulating microscopic effects on macroscopic scales. Using a fully kinetic simulation, the electrostatic ion cyclotron instability due to counterstreaming H(+) beams has been simulated. A power spectrum from the kinetic simulation is used to evaluate second-order exchange rates. The calculated heating and momentum loss from second-order theory is compared to the numerical simulation.

System of extraction of volatiles from soil using microwave processes

NASA Technical Reports Server (NTRS)

Ethridge, Edwin C. (Inventor); Kaukler, William F. (Inventor)

2013-01-01

A device for the extraction and collection of volatiles from soil or planetary regolith. The device utilizes core drilled holes to gain access to underlying volatiles below the surface. Microwave energy beamed into the holes penetrates through the soil or regolith to heat it, and thereby produces vapor by sublimation. The device confines and transports volatiles to a cold trap for collection.

First Experiments with the Polarized Internal Gas Target (PIT) at ANKE/COSY

DOE Office of Scientific and Technical Information (OSTI.GOV)

Engels, R.; Lorentz, B.; Prasuhn, D.

2008-02-06

For future few-nucleon interaction studies with polarized beams and targets at COSY-Juelich, a polarized internal storage-cell gas target was implemented at the magnet spectrometer ANKE in summer 2005. First commissioning of the polarized Atomic Beam Source (ABS) at ANKE was carried out and some improvements of the system have been done. Storage-cell tests to determine the COSY beam dimensions have been performed. Electron cooling combined with stacking and stochastic cooling have been studied. Experiments with N{sub 2} gas in the storage cell to simulate the background produced by beam interaction with the aluminum cell walls were performed to investigate themore » beam heating by the target gas. The analysis of the d-vector p-vector {yields}dp and d-vector p-vector{yields}(dp{sub sp}){pi}{sup 0} reactions showed that events from the extended target can be clearly identified in the ANKE detector system.The polarization of the atomic beam of the ABS, positioned close to the strong dipole magnet D2 of ANKE, was tuned with a Lamb-shift polarimeter (LSP) beneath the target chamber. With use of the known analyzing powers of the quasi-free np{yields}d{pi}{sup 0} reaction, the polarization in the storage cell was measured to be Q{sub y} = 0.79{+-}0.07 in the vertical stray field of the D2 magnet acting as a holding field. The achieved target thickness was 2x10{sup 13} atoms/cm{sup 2} for one hyperfine state populated in the ABS beam only. With a COSY beam intensity of 6x10{sup 9} stored polarized deuterons in the ring, the luminosity for double polarized experiments was 1x10{sup 29} cm{sup -2} s{sup -1}.« less

First Experiments with the Polarized Internal Gas Target (PIT) at ANKE/COSY

DOE Office of Scientific and Technical Information (OSTI.GOV)

Engels, R.; Lorentz, B.; Prasuhn, D.

2009-08-04

For future few-nucleon interaction studies with polarized beams and targets at COSY-Juelich, a polarized internal storage-cell gas target was implemented at the magnet spectrometer ANKE. First commissioning of the polarized Atomic Beam Source (ABS) at ANKE was carried out and some improvements of the system have been done. Storage-cell tests to determine the COSY beam dimensions have been performed. Electron cooling combined with stacking and stochastic cooling have been studied. Experiments with N{sub 2} gas in the storage cell to simulate the background produced by beam interaction with the aluminum cell walls were performed to investigate the beam heating bymore » the target gas. The analysis of the d-vectorp-vector->dp and d-vectorp-vector->(dp{sub sp})pi{sup 0} reactions showed that events from different positions of the extended target can be clearly identified in the ANKE detector system. The polarization of the atomic beam of the ABS, positioned close to the strong dipole magnet D2 of ANKE, was tuned with a Lamb-shift polarimeter (LSP) beneath the target chamber. With use of the known analyzing powers of the quasi-free np->dpi{sup 0} reaction, the polarization in the storage cell was measured to be Q{sub y} = 0.79+-0.07 in the vertical stray field of the D2 magnet acting as a holding field. The target thickness achieved was 2x10{sup 13} atoms/cm{sup 2} for one hyperfine state populated in the ABS beam only. With a COSY beam intensity of 6x10{sup 9} stored polarized deuterons in the ring, the luminosity for double polarized experiments was 1x10{sup 29} cm{sup -2} s{sup -1}.« less

Magnetron sputtering system for coatings deposition with activation of working gas mixture by low-energy high-current electron beam

NASA Astrophysics Data System (ADS)

Gavrilov, N. V.; Kamenetskikh, A. S.; Men'shakov, A. I.; Bureyev, O. A.

2015-11-01

For the purposes of efficient decomposition and ionization of the gaseous mixtures in a system for coatings deposition using reactive magnetron sputtering, a low-energy (100-200 eV) high-current electron beam is generated by a grid-stabilized plasma electron source. The electron source utilizes both continuous (up to 20 A) and pulse-periodic mode of discharge with a self-heated hollow cathode (10-100 A; 0.2 ms; 10-1000 Hz). The conditions for initiation and stable burning of the high-current pulse discharge are studied along with the stable generation of a low-energy electron beam within the gas pressure range of 0.01 - 1 Pa. It is shown that the use of the electron beam with controllable parameters results in reduction of the threshold values both for the pressure of gaseous mixture and for the fluxes of molecular gases. Using such a beam also provides a wide range (0.1-10) of the flux density ratios of ions and sputtered atoms over the coating surface, enables an increase in the maximum pulse density of ion current from plasma up to 0.1 A, ensures an excellent adhesion, optimizes the coating structure, and imparts improved properties to the superhard nanocomposite coatings of (Ti,Al)N/a-Si3N4 and TiC/-a-C:H. Mass-spectrometric measurements of the beam-generated plasma composition proved to demonstrate a twofold increase in the average concentration of N+ ions in the Ar-N2 plasma generated by the high-current (100 A) pulsed electron beam, as compared to the dc electron beam.

High-efficiency concentration/multi-solar-cell system for orbital power generation

NASA Technical Reports Server (NTRS)

Onffroy, J. R.; Stoltzmann, D. E.; Lin, R. J. H.; Knowles, G. R.

1980-01-01

An analysis was performed to determine the economic feasibility of a concentrating spectrophotovoltaic orbital electrical power generation system. In this system dichroic beam-splitting mirrors are used to divide the solar spectrum into several wavebands. Absorption of these wavebands by solar cells with matched energy bandgaps increases the cell efficiency while decreasing the amount of heat which must be rejected. The optical concentration is performed in two stages. The first concentration stage employs a Cassegrain-type telescope, resulting in a short system length. The output from this stage is directed to compound parabolic concentrators which comprise the second stage of concentration. Ideal efficiencies for one-, two-, three-, and four-cell systems were calculated under 1000 sun, AMO conditions, and optimum energy bands were determined. Realistic efficiencies were calculated for various combinations of Si, GaAs, Ge and GaP. Efficiencies of 32 to 33 percent were obtained with the multicell systems. The optimum system consists of an f/3.5 optical system, a beam splitter to divide the spectrum at 0.9 microns, and two solar cell arrays, GaAs and Si.

Engineering aspects of the HT-6M Tokamak

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1986-05-01

The HT-6M is a medium-sized tokamak being built in China. The principal aim of the project is to study high-power auxiliary heating (1-MW neutral beam injection, 1-MW ion cyclotron resonance heating, and 100-kW electron cyclotron resonance heating), high-..beta.. experiments, the transport process, and the formation and diffusion process of impurities. The main device parameters are: major plasma radius R = 65 cm, minor plasma radius a = 20 cm, plasma current I/subP/ = 150 kA, discharge time tau = 150 ms, toroidal field B/subT/ = 15 kG. Simplicity of construction, accessibility to the plasma, reliability in operation, and convenience formore » maintenance were particularly emphasized in the design. The important design features of the device and power supply system are described.« less

Physics of Fusion Welding

NASA Technical Reports Server (NTRS)

Nunes, A. C., Jr.

1986-01-01

Applicabilities and limitations of three techniques analyzed. NASA technical memorandum discusses physics of electron-beam, gas/ tungsten-arc, and laser-beam welding. From comparison of capabilities and limitations of each technique with regard to various welding conditions and materials, possible to develop criteria for selecting best welding technique in specific application. All three techniques classified as fusion welding; small volume of workpiece melted by intense heat source. Heat source moved along seam, leaving in wake solid metal that joins seam edges together.

Aircraft Thermal Management Using Loop Heat Pipes

DTIC Science & Technology

2009-03-01

flexible copper-water arterial wick heat pipe subjected to transverse acceleration using a centrifuge table. Evaporator heat loads up to Qin = 150 W and...acceleration. Yerkes and Beam (1992) examined the same flexible copper-water arterial wick heat pipe as Ponnappan et al. under transient transverse...examined the same flexible copper-water arterial wick heat pipe as Ponnappan et al. with evaporator heat loads from Qin = 75 to 150 W, condenser

Direct Heating of a Laser-Imploded Core by Ultraintense Laser-Driven Ions

NASA Astrophysics Data System (ADS)

Kitagawa, Y.; Mori, Y.; Komeda, O.; Ishii, K.; Hanayama, R.; Fujita, K.; Okihara, S.; Sekine, T.; Satoh, N.; Kurita, T.; Takagi, M.; Watari, T.; Kawashima, T.; Kan, H.; Nishimura, Y.; Sunahara, A.; Sentoku, Y.; Nakamura, N.; Kondo, T.; Fujine, M.; Azuma, H.; Motohiro, T.; Hioki, T.; Kakeno, M.; Miura, E.; Arikawa, Y.; Nagai, T.; Abe, Y.; Ozaki, S.; Noda, A.

2015-05-01

A novel direct core heating fusion process is introduced, in which a preimploded core is predominantly heated by energetic ions driven by LFEX, an extremely energetic ultrashort pulse laser. Consequently, we have observed the D (d ,n )He 3 -reacted neutrons (DD beam-fusion neutrons) with the yield of 5 ×108 n /4 π sr . Examination of the beam-fusion neutrons verified that the ions directly collide with the core plasma. While the hot electrons heat the whole core volume, the energetic ions deposit their energies locally in the core, forming hot spots for fuel ignition. As evidenced in the spectrum, the process simultaneously excited thermal neutrons with the yield of 6 ×107 n /4 π sr , raising the local core temperature from 0.8 to 1.8 keV. A one-dimensional hydrocode STAR 1D explains the shell implosion dynamics including the beam fusion and thermal fusion initiated by fast deuterons and carbon ions. A two-dimensional collisional particle-in-cell code predicts the core heating due to resistive processes driven by hot electrons, and also the generation of fast ions, which could be an additional heating source when they reach the core. Since the core density is limited to 2 g /cm3 in the current experiment, neither hot electrons nor fast ions can efficiently deposit their energy and the neutron yield remains low. In future work, we will achieve the higher core density (>10 g /cm3 ); then hot electrons could contribute more to the core heating via drag heating. Together with hot electrons, the ion contribution to fast ignition is indispensable for realizing high-gain fusion. By virtue of its core heating and ignition, the proposed scheme can potentially achieve high gain fusion.

Direct heating of a laser-imploded core by ultraintense laser-driven ions.

PubMed

Kitagawa, Y; Mori, Y; Komeda, O; Ishii, K; Hanayama, R; Fujita, K; Okihara, S; Sekine, T; Satoh, N; Kurita, T; Takagi, M; Watari, T; Kawashima, T; Kan, H; Nishimura, Y; Sunahara, A; Sentoku, Y; Nakamura, N; Kondo, T; Fujine, M; Azuma, H; Motohiro, T; Hioki, T; Kakeno, M; Miura, E; Arikawa, Y; Nagai, T; Abe, Y; Ozaki, S; Noda, A

2015-05-15

A novel direct core heating fusion process is introduced, in which a preimploded core is predominantly heated by energetic ions driven by LFEX, an extremely energetic ultrashort pulse laser. Consequently, we have observed the D(d,n)^{3}He-reacted neutrons (DD beam-fusion neutrons) with the yield of 5×10^{8} n/4π sr. Examination of the beam-fusion neutrons verified that the ions directly collide with the core plasma. While the hot electrons heat the whole core volume, the energetic ions deposit their energies locally in the core, forming hot spots for fuel ignition. As evidenced in the spectrum, the process simultaneously excited thermal neutrons with the yield of 6×10^{7} n/4π sr, raising the local core temperature from 0.8 to 1.8 keV. A one-dimensional hydrocode STAR 1D explains the shell implosion dynamics including the beam fusion and thermal fusion initiated by fast deuterons and carbon ions. A two-dimensional collisional particle-in-cell code predicts the core heating due to resistive processes driven by hot electrons, and also the generation of fast ions, which could be an additional heating source when they reach the core. Since the core density is limited to 2 g/cm^{3} in the current experiment, neither hot electrons nor fast ions can efficiently deposit their energy and the neutron yield remains low. In future work, we will achieve the higher core density (>10 g/cm^{3}); then hot electrons could contribute more to the core heating via drag heating. Together with hot electrons, the ion contribution to fast ignition is indispensable for realizing high-gain fusion. By virtue of its core heating and ignition, the proposed scheme can potentially achieve high gain fusion.

Use of .sup.3 He.sup.30 + ICRF minority heating to simulate alpha particle heating

DOEpatents

Post, Jr., Douglass E.; Hwang, David Q.; Hovey, Jane

1986-04-22

Neutron activation due to high levels of neutron production in a first heated deuterium-tritium plasma is substantially reduced by using Ion Cyclotron Resonance Frequency (ICRF) heating of energetic .sup.3 He.sup.++ ions in a second deuterium-.sup.3 He.sup.++ plasma which exhibit an energy distribution and density similar to that of alpha particles in fusion reactor experiments to simulate fusion alpha particle heating in the first plasma. The majority of the fast .sup.3 He.sup.++ ions and their slowing down spectrum can be studied using either a modulated hydrogen beam source for producing excited states of He.sup.+ in combination with spectrometers or double charge exchange with a high energy neutral lithium beam and charged particle detectors at the plasma edge. The maintenance problems thus associated with neutron activation are substantially reduced permitting energetic alpha particle behavior to be studied in near term large fusion experiments.

Conceptual studies for a mercury target circuit

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sigg, B.

1996-06-01

For the now favored target design of the European Spallation Source project, i.e. the version using mercury as target material, a basic concept of the primary system has been worked out. It does not include a detailed design of the various components of the target circuit, but tries to outline a feasible solution for the system. Besides the removal of the thermal power of about 3MW produced in the target by the proton beam, the primary system has to satisfy a number of other requirements related to processing, safety, and operation. The basic proposal uses an electromagnetic pump and amore » mercury-water intermediate heat excanger, but other alternatives are also being discussed. Basic safety requirements, i.e. protection against radiation and toxic mercury vapours, are satisfied by a design using an air-tight primary system containment, double-walled tubes in the intermediate heat exchanger, a fail-safe system for decay heat removal, and a remote handling facility for the active part of the system. Much engineering work has still to be done, because many details of the design of the mercury and gas processing systems remain to be clarified, the thermal-hydraulic components need further optimisation, the system for control and instrumentation is only known in outline and a through safety analysis will be required.« less

Radiological Studies for the LCLS Beam Abort System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Santana Leitner, M.; Vollaire, J.; Mao, X.S.

2008-03-25

The Linac Coherent Light Source (LCLS), a pioneer hard x-ray free electron laser is currently under construction at the Stanford Linear Accelerator Center. It is expected that by 2009 LCLS will deliver laser pulses of unprecedented brightness and short length, which will be used in several forefront research applications. This ambitious project encompasses major design challenges to the radiation protection like the numerous sources and the number of surveyed objects. In order to sort those, the showers from various loss sources have been tracked along a detailed model covering 1/2 mile of LCLS accelerator by means of the Monte Carlomore » intra nuclear cascade codes FLUKA and MARS15. This article covers the FLUKA studies of heat load; prompt and residual dose and environmental impact for the LCLS beam abort system.« less

Experimental Characterization of Electron Beam Welded SAE 5137H Thick Steel Plate

NASA Astrophysics Data System (ADS)

Kattire, Prakash; Bhawar, Valmik; Thakare, Sandeep; Patil, Sachin; Mane, Santosh; Singh, Rajkumar, Dr.

2017-09-01

Electron beam welding is known for its narrow weld zone with high depth to width ratio, less heat affected zone, less distortion and contamination. Electron beam welding is fusion welding process, where high velocity electrons impinge on material joint to be welded and kinetic energy of this electron is transformed into heat upon impact to fuse the material. In the present work electron beam welding of 60 mm thick SAE 5137H steel is studied. Mechanical and metallurgical properties of electron beam welded joint of SAE 5137H were evaluated. Mechanical properties are analysed by tensile, impact and hardness test. Metallurgical properties are investigated through optical and scanning electron microscope. The hardness traverse across weld zone shows HV 370-380, about 18% increase in the tensile strength and very low toughness of weld joint compared to parent metal. Microstructural observation shows equiaxed dendrite in the fusion zone and partial grain refinement was found in the HAZ.

Implosion and heating experiments of fast ignition targets by Gekko-XII and LFEX lasers

NASA Astrophysics Data System (ADS)

Shiraga, H.; Fujioka, S.; Nakai, M.; Watari, T.; Nakamura, H.; Arikawa, Y.; Hosoda, H.; Nagai, T.; Koga, M.; Kikuchi, H.; Ishii, Y.; Sogo, T.; Shigemori, K.; Nishimura, H.; Zhang, Z.; Tanabe, M.; Ohira, S.; Fujii, Y.; Namimoto, T.; Sakawa, Y.; Maegawa, O.; Ozaki, T.; Tanaka, K. A.; Habara, H.; Iwawaki, T.; Shimada, K.; Key, M.; Norreys, P.; Pasley, J.; Nagatomo, H.; Johzaki, T.; Sunahara, A.; Murakami, M.; Sakagami, H.; Taguchi, T.; Norimatsu, T.; Homma, H.; Fujimoto, Y.; Iwamoto, A.; Miyanaga, N.; Kawanaka, J.; Kanabe, T.; Jitsuno, T.; Nakata, Y.; Tsubakimoto, K.; Sueda, K.; Kodama, R.; Kondo, K.; Morio, N.; Matsuo, S.; Kawasaki, T.; Sawai, K.; Tsuji, K.; Murakami, H.; Sarukura, N.; Shimizu, T.; Mima, K.; Azechi, H.

2013-11-01

The FIREX-1 project, the goal of which is to demonstrate fuel heating up to 5 keV by fast ignition scheme, has been carried out since 2003 including construction and tuning of LFEX laser and integrated experiments. Implosion and heating experiment of Fast Ignition targets have been performed since 2009 with Gekko-XII and LFEX lasers. A deuterated polystyrene shell target was imploded with the 0.53- μm Gekko-XII, and the 1.053- μm beam of the LFEX laser was injected through a gold cone attached to the shell to generate hot electrons to heat the imploded fuel plasma. Pulse contrast ratio of the LFEX beam was significantly improved. Also a variety of plasma diagnostic instruments were developed to be compatible with harsh environment of intense hard x-rays (γ rays) and electromagnetic pulses due to the intense LFEX beam on the target. Large background signals around the DD neutron signal in time-of-flight record of neutron detector were found to consist of neutrons via (γ,n) reactions and scattered gamma rays. Enhanced neutron yield was confirmed by carefully eliminating such backgrounds. Neutron enhancement up to 3.5 × 107 was observed. Heating efficiency was estimated to be 10-20% assuming a uniform temperature rise model.

Thermal radiation heat transfer in participating media by finite volume discretization using collimated beam incidence

NASA Astrophysics Data System (ADS)

Harijishnu, R.; Jayakumar, J. S.

2017-09-01

The main objective of this paper is to study the heat transfer rate of thermal radiation in participating media. For that, a generated collimated beam has been passed through a two dimensional slab model of flint glass with a refractive index 2. Both Polar and azimuthal angle have been varied to generate such a beam. The Temperature of the slab and Snells law has been validated by Radiation Transfer Equation (RTE) in OpenFOAM (Open Field Operation and Manipulation), a CFD software which is the major computational tool used in Industry and research applications where the source code is modified in which radiation heat transfer equation is added to the case and different radiation heat transfer models are utilized. This work concentrates on the numerical strategies involving both transparent and participating media. Since Radiation Transfer Equation (RTE) is difficult to solve, the purpose of this paper is to use existing solver buoyantSimlpeFoam to solve radiation model in the participating media by compiling the source code to obtain the heat transfer rate inside the slab by varying the Intensity of radiation. The Finite Volume Method (FVM) is applied to solve the Radiation Transfer Equation (RTE) governing the above said physical phenomena.

Results of RIKEN superconducting electron cyclotron resonance ion source with 28 GHz.

PubMed

Higurashi, Y; Ohnishi, J; Nakagawa, T; Haba, H; Tamura, M; Aihara, T; Fujimaki, M; Komiyama, M; Uchiyama, A; Kamigaito, O

2012-02-01

We measured the beam intensity of highly charged heavy ions and x-ray heat load for RIKEN superconducting electron cyclotron resonance ion source with 28 GHz microwaves under the various conditions. The beam intensity of Xe(20+) became maximum at B(min) ∼ 0.65 T, which was ∼65% of the magnetic field strength of electron cyclotron resonance (B(ECR)) for 28 GHz microwaves. We observed that the heat load of x-ray increased with decreasing gas pressure and field gradient at resonance zone. It seems that the beam intensity of highly charged heavy ions with 28 GHz is higher than that with 18 GHz at same RF power.

Electron spectroscopy of the diamond surface

NASA Technical Reports Server (NTRS)

Pepper, S. V.

1981-01-01

The diamond surface is studied by ionization loss spectroscopy and Auger electron spectroscopy. For surfaces heated to temperatures not exceeding 900 C, the band gap was found to be devoid of empty states in the absence of electron beam effects. The incident electron beam generates empty states in the band gap and loss of structure in the valence band for these surfaces. A cross section of 1.4 x 10 to the -19th sq cm was obtained for this effect. For surfaces heated to temperatures exceeding 900 C the spectra were identical to those from surfaces modified by the electron beam. The diamond surface undergoes a thermal conversion in its electronic structure at about 900 C.

Self-monitored photothermal nanoparticles based on core-shell engineering

NASA Astrophysics Data System (ADS)

Ximendes, Erving C.; Rocha, Uéslen; Jacinto, Carlos; Kumar, Kagola Upendra; Bravo, David; López, Fernando J.; Rodríguez, Emma Martín; García-Solé, José; Jaque, Daniel

2016-01-01

The continuous development of nanotechnology has resulted in the actual possibility of the design and synthesis of nanostructured materials with pre-tailored functionabilities. Nanostructures capable of simultaneous heating and local thermal sensing are in strong demand as they would constitute a revolutionary solution to several challenging problems in bio-medicine, including the achievement of real time control during photothermal therapies. Several approaches have been demonstrated to achieve simultaneous heating and thermal sensing at the nanoscale. Some of them lack of sufficient thermal sensitivity and others require complicated synthesis procedures for heterostructure fabrication. In this study, we demonstrate how single core/shell dielectric nanoparticles with a highly Nd3+ ion doped shell and an Yb3+,Er3+ codoped core are capable of simultaneous thermal sensing and heating under an 808 nm single beam excitation. The spatial separation between the heating shell and sensing core provides remarkable values of the heating efficiency and thermal sensitivity, enabling their application in single beam-controlled heating experiments in both aqueous and tissue environments.

Numerical studies on alpha production from high energy proton beam interaction with Boron

NASA Astrophysics Data System (ADS)

Moustaizis, S. D.; Lalousis, P.; Hora, H.; Korn, G.

2017-05-01

Numerical investigations on high energy proton beam interaction with high density Boron plasma allows to simulate conditions concerning the alpha production from recent experimental measurements . The experiments measure the alpha production due to p11B nuclear fusion reactions when a laser-driven high energy proton beam interacts with Boron plasma produced by laser beam interaction with solid Boron. The alpha production and consequently the efficiency of the process depends on the initial proton beam energy, proton beam density, the Boron plasma density and temperature, and their temporal evolution. The main advantage for the p11B nuclear fusion reaction is the production of three alphas with total energy of 8.9 MeV, which could enhance the alpha heating effect and improve the alpha production. This particular effect is termed in the international literature as the alpha avalanche effect. Numerical results using a multi-fluid, global particle and energy balance, code shows the alpha production efficiency as a function of the initial energy of the proton beam, the Boron plasma density, the initial Boron plasma temperature and the temporal evolution of the plasma parameters. The simulations enable us to determine the interaction conditions (proton beam - B plasma) for which the alpha heating effect becomes important.

Development and application of a water calorimeter for the absolute dosimetry of short-range particle beams.

PubMed

Renaud, J; Rossomme, S; Sarfehnia, A; Vynckier, S; Palmans, H; Kacperek, A; Seuntjens, J

2016-09-21

In this work, we describe a new design of water calorimeter built to measure absorbed dose in non-standard radiation fields with reference depths in the range of 6-20 mm, and its initial testing in clinical electron and proton beams. A functioning calorimeter prototype with a total water equivalent thickness of less than 30 mm was constructed in-house and used to obtain measurements in clinical accelerator-based 6 MeV and 8 MeV electron beams and cyclotron-based 60 MeV monoenergetic and modulated proton beams. Corrections for the conductive heat transfer due to dose gradients and non-water materials was also accounted for using a commercial finite element method software package. Absorbed dose to water was measured with an associated type A standard uncertainty of approximately 0.4% and 0.2% for the electron and proton beam experiments, respectively. In terms of thermal stability, drifts were on the order of a couple of hundred µK min -1 , with a short-term variation of 5-10 µK. Heat transfer correction factors ranged between 1.021 and 1.049. The overall combined standard uncertainty on the absorbed dose to water was estimated to be 0.6% for the 6 MeV and 8 MeV electron beams, as well as for the 60 MeV monoenergetic protons, and 0.7% for the modulated 60 MeV proton beam. This study establishes the feasibility of developing an absorbed dose transfer standard for short-range clinical electrons and protons and forms the basis for a transportable dose standard for direct calibration of ionization chambers in the user's beam. The largest contributions to the combined standard uncertainty were the positioning (⩽0.5%) and the correction due to conductive heat transfer (⩽0.4%). This is the first time that water calorimetry has been used in such a low energy proton beam.

Development and application of a water calorimeter for the absolute dosimetry of short-range particle beams

NASA Astrophysics Data System (ADS)

Renaud, J.; Rossomme, S.; Sarfehnia, A.; Vynckier, S.; Palmans, H.; Kacperek, A.; Seuntjens, J.

2016-09-01

In this work, we describe a new design of water calorimeter built to measure absorbed dose in non-standard radiation fields with reference depths in the range of 6-20 mm, and its initial testing in clinical electron and proton beams. A functioning calorimeter prototype with a total water equivalent thickness of less than 30 mm was constructed in-house and used to obtain measurements in clinical accelerator-based 6 MeV and 8 MeV electron beams and cyclotron-based 60 MeV monoenergetic and modulated proton beams. Corrections for the conductive heat transfer due to dose gradients and non-water materials was also accounted for using a commercial finite element method software package. Absorbed dose to water was measured with an associated type A standard uncertainty of approximately 0.4% and 0.2% for the electron and proton beam experiments, respectively. In terms of thermal stability, drifts were on the order of a couple of hundred µK min-1, with a short-term variation of 5-10 µK. Heat transfer correction factors ranged between 1.021 and 1.049. The overall combined standard uncertainty on the absorbed dose to water was estimated to be 0.6% for the 6 MeV and 8 MeV electron beams, as well as for the 60 MeV monoenergetic protons, and 0.7% for the modulated 60 MeV proton beam. This study establishes the feasibility of developing an absorbed dose transfer standard for short-range clinical electrons and protons and forms the basis for a transportable dose standard for direct calibration of ionization chambers in the user’s beam. The largest contributions to the combined standard uncertainty were the positioning (⩽0.5%) and the correction due to conductive heat transfer (⩽0.4%). This is the first time that water calorimetry has been used in such a low energy proton beam.

Calculation of prompt loss and toroidal field ripple loss under neutral beam injection on EAST

NASA Astrophysics Data System (ADS)

Wu, Bin; Hao, Baolong; White, Roscoe; Wang, Jinfang; Zang, Qing; Han, Xiaofeng; Hu, Chundong

2017-02-01

Neutral beam injection is a major auxiliary heating method in the EAST experimental campaign. This paper gives detailed calculations of beam loss with different plasma equilibria using the guiding center code ORBIT and NUBEAM/TRANSP. Increasing plasma current can dramatically lower the beam ion prompt loss and ripple loss. Countercurrent beam injection gives a much larger prompt loss fraction than co-injection, and ripple-induced collisionless stochastic diffusion is the dominant loss channel.

Calculation of prompt loss and toroidal field ripple loss under neutral beam injection on EAST

DOE PAGES

Wu, Bin; Hao, Baolong; White, Roscoe; ...

2016-12-09

Here, neutral beam injection is a major auxiliary heating method in the EAST experimental campaign. This paper gives detailed calculations of beam loss with different plasma equilibria using the guiding center code ORBIT and NUBEAM/TRANSP. Increasing plasma current can dramatically lower the beam ion prompt loss and ripple loss. Countercurrent beam injection gives a much larger prompt loss fraction than co-injection, and ripple-induced collisionless stochastic diffusion is the dominant loss channel.

Calculation of prompt loss and toroidal field ripple loss under neutral beam injection on EAST

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wu, Bin; Hao, Baolong; White, Roscoe

Here, neutral beam injection is a major auxiliary heating method in the EAST experimental campaign. This paper gives detailed calculations of beam loss with different plasma equilibria using the guiding center code ORBIT and NUBEAM/TRANSP. Increasing plasma current can dramatically lower the beam ion prompt loss and ripple loss. Countercurrent beam injection gives a much larger prompt loss fraction than co-injection, and ripple-induced collisionless stochastic diffusion is the dominant loss channel.

Molecular beam epitaxy growth of niobium oxides by solid/liquid state oxygen source and lithium assisted metal-halide chemistry

NASA Astrophysics Data System (ADS)

Tellekamp, M. Brooks; Greenlee, Jordan D.; Shank, Joshua C.; Doolittle, W. Alan

2015-09-01

In order to consistently grow high quality niobium oxides and lithium niobium oxides, a novel solid/liquid state oxygen source, LiClO4, has been implemented in a molecular beam epitaxy (MBE) system. LiClO4 is shown to decompose into both molecular and atomic oxygen upon heating. This allows oxidation rates similar to that of molecular oxygen but at a reduced overall beam flux, quantified by in situ Auger analysis. LiClO4 operation is decomposition limited to less than 400 °C, and other material limitations are identified. The design of a custom near-ambient NbCl5 effusion cell is presented, which improves both short and long term stability. Films of Nb oxidation state +2, +3, and +5 are grown using these new tools, including the multi-functional sub-oxide LiNbO2.

Heat pipe cooling of power processing magnetics

NASA Technical Reports Server (NTRS)

Hansen, I. G.; Chester, M.

1979-01-01

The constant demand for increased power and reduced mass has raised the internal temperature of conventionally cooled power magnetics toward the upper limit of acceptability. The conflicting demands of electrical isolation, mechanical integrity, and thermal conductivity preclude significant further advancements using conventional approaches. However, the size and mass of multikilowatt power processing systems may be further reduced by the incorporation of heat pipe cooling directly into the power magnetics. Additionally, by maintaining lower more constant temperatures, the life and reliability of the magnetic devices will be improved. A heat pipe cooled transformer and input filter have been developed for the 2.4 kW beam supply of a 30-cm ion thruster system. This development yielded a mass reduction of 40% (1.76 kg) and lower mean winding temperature (20 C lower). While these improvements are significant, preliminary designs predict even greater benefits to be realized at higher power. This paper presents the design details along with the results of thermal vacuum operation and the component performance in a 3 kW breadboard power processor.

Precision Control of Thermal Transport in Cryogenic Single-Crystal Silicon Devices

NASA Technical Reports Server (NTRS)

Rostem, K.; Chuss, D. T.; Colazo, F. A.; Crowe, E. J.; Denis, K. L.; Lourie, N. P.; Moseley, S. H.; Stevenson, T. R.; Wollack, E. J.

2014-01-01

We report on the diffusive-ballistic thermal conductance of multi-moded single-crystal silicon beams measured below 1 K. It is shown that the phonon mean-free-path is a strong function of the surface roughness characteristics of the beams. This effect is enhanced in diffuse beams with lengths much larger than, even when the surface is fairly smooth, 510 nm rms, and the peak thermal wavelength is 0.6 microns. Resonant phonon scattering has been observed in beams with a pitted surface morphology and characteristic pit depth of 30 nm. Hence, if the surface roughness is not adequately controlled, the thermal conductance can vary significantly for diffuse beams fabricated across a wafer. In contrast, when the beam length is of order, the conductance is dominated by ballistic transport and is effectively set by the beam cross-sectional area. We have demonstrated a uniformity of +/-8% in fractional deviation for ballistic beams, and this deviation is largely set by the thermal conductance of diffuse beams that support the micro-electro-mechanical device and electrical leads. In addition, we have found no evidence for excess specific heat in single-crystal silicon membranes. This allows for the precise control of the device heat capacity with normal metal films. We discuss the results in the context of the design and fabrication of large-format arrays of far-infrared and millimeter wavelength cryogenic detectors.

Enhanced laser beam coupling to a plasma

DOEpatents

Steiger, Arno D.; Woods, Cornelius H.

1976-01-01

Density perturbations are induced in a heated plasma by means of a pair of oppositely directed, polarized laser beams of the same frequency. The wavelength of the density perturbations is equal to one half the wavelength of the laser beams. A third laser beam is linearly polarized and directed at the perturbed plasma along a line that is perpendicular to the direction of the two opposed beams. The electric field of the third beam is oriented to lie in the plane containing the three beams. The frequency of the third beam is chosen to cause it to interact resonantly with the plasma density perturbations, thereby efficiently coupling the energy of the third beam to the plasma.

Accelerator-based neutron source for boron neutron capture therapy (BNCT) and method

DOEpatents

Yoon, W.Y.; Jones, J.L.; Nigg, D.W.; Harker, Y.D.

1999-05-11

A source for boron neutron capture therapy (BNCT) comprises a body of photoneutron emitter that includes heavy water and is closely surrounded in heat-imparting relationship by target material; one or more electron linear accelerators for supplying electron radiation having energy of substantially 2 to 10 MeV and for impinging such radiation on the target material, whereby photoneutrons are produced and heat is absorbed from the target material by the body of photoneutron emitter. The heavy water is circulated through a cooling arrangement to remove heat. A tank, desirably cylindrical or spherical, contains the heavy water, and a desired number of the electron accelerators circumferentially surround the tank and the target material as preferably made up of thin plates of metallic tungsten. Neutrons generated within the tank are passed through a surrounding region containing neutron filtering and moderating materials and through neutron delimiting structure to produce a beam or beams of epithermal neutrons normally having a minimum flux intensity level of 1.0{times}10{sup 9} neutrons per square centimeter per second. Such beam or beams of epithermal neutrons are passed through gamma ray attenuating material to provide the required epithermal neutrons for BNCT use. 3 figs.

Accelerator-based neutron source for boron neutron capture therapy (BNCT) and method

DOEpatents

Yoon, Woo Y.; Jones, James L.; Nigg, David W.; Harker, Yale D.

1999-01-01

A source for boron neutron capture therapy (BNCT) comprises a body of photoneutron emitter that includes heavy water and is closely surrounded in heat-imparting relationship by target material; one or more electron linear accelerators for supplying electron radiation having energy of substantially 2 to 10 MeV and for impinging such radiation on the target material, whereby photoneutrons are produced and heat is absorbed from the target material by the body of photoneutron emitter. The heavy water is circulated through a cooling arrangement to remove heat. A tank, desirably cylindrical or spherical, contains the heavy water, and a desired number of the electron accelerators circumferentially surround the tank and the target material as preferably made up of thin plates of metallic tungsten. Neutrons generated within the tank are passed through a surrounding region containing neutron filtering and moderating materials and through neutron delimiting structure to produce a beam or beams of epithermal neutrons normally having a minimum flux intensity level of 1.0.times.10.sup.9 neutrons per square centimeter per second. Such beam or beams of epithermal neutrons are passed through gamma ray attenuating material to provide the required epithermal neutrons for BNCT use.

Tunable mega-ampere electron current propagation in solids by dynamic control of lattice melt

DOE PAGES

MacLellan, D.  A.; Carroll, D.  C.; Gray, R.  J.; ...

2014-10-31

The influence of lattice-melt-induced resistivity gradients on the transport of mega-ampere currents of fast electrons in solids is investigated numerically and experimentally using laser-accelerated protons to induce isochoric heating. Tailoring the heating profile enables the resistive magnetic fields which strongly influence the current propagation to be manipulated. This tunable laser-driven process enables important fast electron beam properties, including the beam divergence, profile, and symmetry to be actively tailored, and without recourse to complex target manufacture.

Numerical Analysis of a Single Microchannel Within a High-Temperature Hydrogen Heat Exchanger for Beamed Energy Propulsion Applications

DTIC Science & Technology

2013-07-01

was subtracted. Here, based on prospective tube shell materials such as carbon fiber reinforced carbon , an emissivity of .9 was chosen. The...Conference Paper 3. DATES COVERED (From - To) 14 Jul 2013 – 19 Jul 2013 4. TITLE AND SUBTITLE Numerical Analysis of a Single Microchannel Within a High ...energy to the spacecraft via microwaves . This work computationally models three different heat exchanger channel designs for use in a beam

Measurement of magnetic property of FePt granular media at near Curie temperature

NASA Astrophysics Data System (ADS)

Yang, H. Z.; Chen, Y. J.; Leong, S. H.; An, C. W.; Ye, K. D.; Hu, J. F.

2017-02-01

The characterization of the magnetic switching behavior of heat assisted magnetic recording (HAMR) media at near Curie temperature (Tc) is important for high density recording. In this study, we measured the magnetic property of FePt granular media (with room temperature coercivity 25 kOe) at near Tc with a home built HAMR testing instrument. The local area of HAMR media is heated to near Tc by a flat-top optical heating beam. The magnetic property in the heated area was in-situ measured by a magneto-optic Kerr effect (MOKE) testing beam. The switching field distribution (SFD) and coercive field (Hc) of the FePt granular media and their dependence on the optical heating power at near Tc were studied. We measured the DC demagnetization (DCD) signal with pulsed laser heating at different optical powers. We also measured the Tc distribution of the media by measuring the AC magnetic signal as a function of optical heating power. In a summary, we studied the SFD, Hc of the HAMR media at near Tc in a static manner. The present methodology will facilitate the HAMR media testing.

Proton Beam Driven Isochoric Heating to Warm Dense Matter Conditions on Texas Petawatt

NASA Astrophysics Data System (ADS)

Roycroft, R.; Dyer, G. M.; McCary, E.; Jiao, X.; Bowers, B.; Bernstein, A.; Ditmire, T.; Montgomery, M.; Winget, D.; Hegelich, B. M.

2017-10-01

Isochoric heating of solids and gases to warm dense matter conditions is relevant to the study of equation of state as well as laboratory astrophysics, specifically heating of hydrogen gas ( 1017-1019 cm3) to 0.5-3eV for the study of white dwarf atmospheres. In a series of experiments on Texas Petawatt, we have built a platform using the petawatt laser focused softly to a large focal spot (60-70um) to generate large numbers of intermediate energy protons via TNSA, ideal for isochoric heating. We have previously used the proton beam to isochorically heat 10um aluminum foils to 20eV. This poster presents results of experiments in which low Z materials such as methane gas, carbon foams, and hydrogen are heated using this platform. We are measuring the surface brightness temperature and heating with a streaked optical pyrometer, and XUV emissions using an XUV spectrometer. Supported by NNSA cooperative agreement DE-NA0002008, the DARPA PULSE program (12-63-PULSE-FP014), and the Air Force Office of Scientific Research (FA9550-14-1-0045).

Apparatus and method for quantitative measurement of small differences in optical absorptivity between two samples using differential interferometry and the thermooptic effect

DOEpatents

Cremers, D.A.; Keller, R.A.

1984-05-08

An apparatus and method for the measurement of small differences in optical absorptivity of weakly absorbing solutions using differential interferometry and the thermooptic effect have been developed. Two sample cells are placed in each arm of an interferometer and are traversed by colinear probe and heating laser beams. The interrogation probe beams are recombined forming a fringe pattern, the intensity of which can be related to changes in optical path length of these laser beams through the cells. This in turn can be related to small differences in optical absorptivity which results in different amounts of sample heating when the heating laser beams are turned on, by the fact that the index of refraction of a liquid is temperature dependent. A critical feature of this invention is the stabilization of the optical path of the probe beams against drift. Background (solvent) absorption can then be suppressed by a factor of approximately 400. Solute absorptivities of about 10[sup [minus]5] cm[sup [minus]1] can then be determined in the presence of background absorptions in excess of 10[sup [minus]3] cm[sup [minus]1]. In addition, the smallest absorption measured with the instant apparatus and method is about 5 [times] 10[sup [minus]6] cm[sup [minus]1]. 6 figs.

Erosion of newly developed CFCs and Be under disruption heat loads

NASA Astrophysics Data System (ADS)

Nakamura, K.; Akiba, M.; Araki, M.; Dairaku, M.; Sato, K.; Suzuki, S.; Yokoyama, K.; Linke, J.; Duwe, R.; Bolt, H.; Roedig, M.

1996-10-01

An evaluation of the erosion under disruption heat loads is very important to the lifetime prediction of divertor armour tiles of next fusion devices such as ITER. In particular, erosion data on CFCs (carbon fiber reinforced composites) and beryllium (Be) as the armour materials is urgently required in the ITER design. For CFCs, high heat flux experiments on the newly developed CFCs with high thermal conductivity have been performed under the heat flux of around 800-2000 MW/m 2 and the pulse length of 2-5 ms in JAERI electron beam irradiation systems (JEBIS). As a result, the weight losses of B 4C doped CFCs after heating were almost same to those of the non doped CFC up to 5 wt% boron content. For Be, we have carried out our first disruption experiments on S65/C grade Be specimens in the Juelich divertor test facility in hot cells (JUDITH) facility as a frame work of the J—EU collaboration. The heating conditions were heat loads of 1250-5000 MW/m 2 for 2-8 ms, and the heated area was 3 × 3 mm 2. As a result, the protuberances of the heated area of Be were observed under the lower heat flux.

Physics of light and lasers.

PubMed

Absten, G T

1991-09-01

Because most laser procedures use the heating effect of the light and given the number of parameters that may be varied--such as power density, power, pulsing, and heating of fiber tips and probes--significant overlap in applications of the various lasers can result. This is readily apparent in the conflicting claims of laser manufacturers seen in promotional materials. Despite this, each type has its strengths. The CO2 laser is a specialty instrument, particularly for microscopic applications in neurosurgery, otolaryngology, and gynecology. Its hemostasis and vaporizing abilities allow its use in dermatology and in general surgery for tumor resection and hemostasis. In gynecology it seems best for colposcopy (cervical and vaginal) and, through a micromanipulator, for laparotomy. The beam is focused and delivered by handpieces and micromanipulators on microscopes. Through the laparoscope, it requires the use of a special laser coupler on a special laser laparoscope to allow for line-of-sight delivery of the beam through the operating channel. Waveguide delivery systems have been introduced for CO2 laser laparoscopy using standard laparoscopes. These function as hollow, slender tubes through which the beam is transmitted by means of hundreds of glancing internal reflections in the tube, which emits the beam at its tip. This eliminates many of the alignment problems of coupler cube-type systems and allows the beam to be delivered close to the target. The Nd:YAG laser is the primary endoscopic instrument in pulmonology, gastroenterology, and urology. The use of contact tips, though not a panacea, increases its applications, particularly in general surgery. Its primary use in gynecology is for endometrial ablation with bare fibers for deep coagulation. Its use for laparoscopy with contact probes or sculpted fibers is quickly growing. Green light lasers (argon and KTP) are color-selective photocoagulators and may be used to cut tissue. They are fiberoptically delivered like the Nd:YAG laser. Their best use in gynecology appears to be a versatile instruments for operative laparoscopy and the simple treatment of endometriosis. A standard quartz fiber with these lasers is usually more versatile than a contact tip with an Nd:YAG laser when used for cutting.

Specific features of measuring the isotopic composition of hydrogen ions in ITER plasma by using neutral particle diagnostics under neutral beam injection conditions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Afanasyev, V. I.; Goncharov, P. R., E-mail: p.goncharov@spbstu.ru; Mironov, M. I.

2015-12-15

Results of numerical simulation of signals from neutral particle analyzers under injection of the heating and diagnostic neutral beams in different operating modes of the ITER tokamak are presented. The distribution functions of fast ions in plasma are simulated, and the corresponding neutral particle fluxes escaping from the plasma along the line of sight of the analyzers are calculated. It is shown that the injection of heating deuterium (D{sup 0}) beams results in the appearance of an intense background signal hampering measurements of the ratio between the densities of deuterium and tritium fuel ions in plasma in the thermal energymore » range. The injection of a diagnostic hydrogen (H{sup 0}) beam does not affect measurements owing to the high mass resolution of the analyzers.« less

A laser beam quality definition based on induced temperature rise.

PubMed

Miller, Harold C

2012-12-17

Laser beam quality metrics like M(2) can be used to describe the spot sizes and propagation behavior of a wide variety of non-ideal laser beams. However, for beams that have been diffracted by limiting apertures in the near-field, or those with unusual near-field profiles, the conventional metrics can lead to an inconsistent or incomplete description of far-field performance. This paper motivates an alternative laser beam quality definition that can be used with any beam. The approach uses a consideration of the intrinsic ability of a laser beam profile to heat a material. Comparisons are made with conventional beam quality metrics. An analysis on an asymmetric Gaussian beam is used to establish a connection with the invariant beam propagation ratio.

Performance enhanced piezoelectric-based crack detection system for high temperature I-beam SHM

NASA Astrophysics Data System (ADS)

Zhang, Chen; Zhang, Haifeng

2017-04-01

This paper proposes an innovative sensing system for high temperature (up to 150°C) I-beam crack detection. The proposed system is based on the piezoelectric effect and laser sensing mechanisms, which is proved to be effective at high temperature environment (up to 150°C). Different from other high temperature SHM approaches, the proposed sensing system is employing a piezoelectric disk as an actuator and a laser vibrometer as a sensor for remote detection. Lab tests are carried out and the vibrational properties are studied to characterize the relationship between crack depth and sensor responses by analyzing the RMS of sensor responses. Instead of utilizing a pair of piezoelectric actuator and sensor, using the laser vibrometer will enable 1) a more flexible detection, which will not be limited to specific area or dimension, 2) wireless sensing, which lowers the risk of operating at high temperature/harsh environment. The proposed sensing system can be applied to engineering structures such as in nuclear power plant reactor vessel and heat pipe structures/systems.

Extension of the ECRH operational space with O2 and X3 heating schemes to control tungsten accumulation in ASDEX Upgrade

NASA Astrophysics Data System (ADS)

Höhnle, H.; Stober, J.; Herrmann, A.; Kasparek, W.; Leuterer, F.; Monaco, F.; Neu, R.; Schmid-Lorch, D.; Schütz, H.; Schweinzer, J.; Stroth, U.; Wagner, D.; Vorbrugg, S.; Wolfrum, E.; ASDEX Upgrade Team

2011-08-01

ASDEX Upgrade has been operated with tungsten-coated plasma-facing components for several years. H-mode operation with good confinement has been demonstrated. Nevertheless, purely neutral beam injection-heated H-modes with reduced gas puff, moderate heating power or/and increased triangularity tend to accumulate tungsten, followed by a radiative collapse. Under these conditions, central electron heating with electron cyclotron resonance heating (ECRH), usually in X2 polarization, changes the impurity transport in the plasma centre, reducing the central tungsten concentration and, in many cases, stabilizing the plasma. In order to extend the applicability of central ECRH to a wider range of magnetic field and plasma current additional ECRH schemes with reduced single-pass absorption have been implemented: X3 heating allows us to reduce the magnetic field by 30%, such that the first H-modes with an ITER-like value of the safety factor of q95 = 3 could be run in the tungsten-coated device. O2 heating increases the cutoff density by a factor of 2 allowing higher currents and triangularities to be addressed. For both schemes, scenarios have been developed to cope with the associated reduced absorption. In the case of central X3 heating, the X2 resonance lies close to the pedestal top at the high-field side of the plasma, serving as a beam dump. For O2, holographic mirrors have been developed which guarantee a second pass through the plasma centre. The beam position on these reflectors is controlled by fast thermocouples. Stray-radiation protection has been implemented using sniffer probes.

Monte Carlo calculation model for heat radiation of inclined cylindrical flames and its application

NASA Astrophysics Data System (ADS)

Chang, Zhangyu; Ji, Jingwei; Huang, Yuankai; Wang, Zhiyi; Li, Qingjie

2017-07-01

Based on Monte Carlo method, a calculation model and its C++ calculating program for radiant heat transfer from an inclined cylindrical flame are proposed. In this model, the total radiation energy of the inclined cylindrical flame is distributed equally among a certain number of energy beams, which are emitted randomly from the flame surface. The incident heat flux on a surface is calculated by counting the number of energy beams which could reach the surface. The paper mainly studies the geometrical evaluation criterion for validity of energy beams emitted by inclined cylindrical flames and received by other surfaces. Compared to Mudan's formula results for a straight cylinder or a cylinder with 30° tilt angle, the calculated view factors range from 0.0043 to 0.2742 and the predicted view factors agree well with Mudan's results. The changing trend and values of incident heat fluxes computed by the model is consistent with experimental data measured by Rangwala et al. As a case study, incident heat fluxes on a gasoline tank, both the side and the top surface are calculated by the model. The heat radiation is from an inclined cylindrical flame generated by another 1000 m3 gasoline tank 4.6 m away from it. The cone angle of the flame to the adjacent oil tank is 45° and the polar angle is 0°. The top surface and the side surface of the tank are divided into 960 and 5760 grids during the calculation, respectively. The maximum incident heat flux on the side surface is 39.64 and 51.31 kW/m2 on the top surface. Distributions of the incident heat flux on the surface of the oil tank and on the ground around the fire tank are obtained, too.

Modeling activities on the negative-ion-based Neutral Beam Injectors of the Large Helical Device

DOE Office of Scientific and Technical Information (OSTI.GOV)

Agostinetti, P.; Antoni, V.; Chitarin, G.

2011-09-26

At the National Institute for Fusion Science (NIFS) large-scaled negative ion sources have been widely used for the Neutral Beam Injectors (NBIs) mounted on the Large Helical Device (LHD), which is the world-largest superconducting helical system. These injectors have achieved outstanding performances in terms of beam energy, negative-ion current and optics, and represent a reference for the development of heating and current drive NBIs for ITER.In the framework of the support activities for the ITER NBIs, the PRIMA test facility, which includes a RF-drive ion source with 100 keV accelerator (SPIDER) and a complete 1 MeV Neutral Beam system (MITICA)more » is under construction at Consorzio RFX in Padova.An experimental validation of the codes has been undertaken in order to prove the accuracy of the simulations and the soundness of the SPIDER and MITICA design. To this purpose, the whole set of codes have been applied to the LHD NBIs in a joint activity between Consorzio RFX and NIFS, with the goal of comparing and benchmarking the codes with the experimental data. A description of these modeling activities and a discussion of the main results obtained are reported in this paper.« less

Enhanced photothermal lens using a photonic crystal surface

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhao, Yunfei; Liu, Longju; Zhao, Xiangwei

2016-08-15

A photonic crystal (PC)-enhanced photothermal lens (PTL) is demonstrated for the detection of optically thin light absorption materials. The PC-enhanced PTL system is based on a pump-probe scheme consisting of a PC surface, pump laser beam, and probe laser beam. Heated by the pump beam, light absorption materials on the PC surface generate the PTL and cause a substantial change to the guided-mode resonance supported by the PC structure. The change of the PC resonance is detected using the probe laser beam by measuring its reflectivity from the PC surface. When applied to analyze dye molecules deposited on the PCmore » substrate, the developed system is capable of enhancing the PTL signal by 10-fold and reducing the lowest distinguishable concentration by 8-fold, in comparison to measuring without utilizing the PC resonance. The PC-enhanced PTL was also used to detect gold nanoparticles on the PC surface and exhibited a 20-fold improvement of the lowest distinguishable concentration. The PC-enhanced PTL technology offers a potential tool to obtain the absorption signatures of thin films in a broad spectral range with high sensitivity and inexpensive instrumentation. As a result, this technology will enable a broad range of applications of photothermal spectroscopy in chemical analysis and biomolecule sensing.« less

The Physics Performance Of The Front Steering Launcher For The ITER ECRH Upper Port

DOE Office of Scientific and Technical Information (OSTI.GOV)

Henderson, M.; Chavan, R.; Nikkola, P.

2005-09-26

The capability of any given e.m.-wave plasma heating system to be utilized for physics applications depends strongly on the technical properties of the launching antenna (or launcher). An effective ECH launcher must project a small mm-wave beam spot size far into the plasma and 'steer' the beam across a large fraction of the plasma cross section (along the resonance surface). Thus the choice in the launcher concept and design may either severely limit or enhance the capability of a heating system to be effectively applied for physics applications, such as sawtooth stabilization, control of the Neoclassical Tearing Mode (NTM), Edgemore » Localized Mode (ELM) control, etc. Presently, two antenna concepts are under consideration for the ITER upper port ECH launcher: front steering (FS) and remote steering (RS) launchers. The RS launcher has the technical advantage of easier maintenance access to the steering mirror, which is isolated from the torus vacuum. The FS launcher places the steering mirror near the plasma increasing the technical challenges, but significantly enhancing the focusing and steering capabilities of the launcher, offering a threefold increase in NTM stabilization efficiency over the RS launcher as well as the potential for application to other critical physics issues such as ELM or sawtooth control.« less

40 CFR 60.703 - Monitoring of emissions and operations.

Code of Federal Regulations, 2011 CFR

2011-07-01

... position before any substantial heat exchange is encountered. (ii) Where a catalytic incinerator is used... equipment: (1) A heat sensing device, such as an ultraviolet beam sensor or thermocouple, at the pilot light... 44 MW (150 million Btu/hr) design heat input capacity. Any vent stream introduced with primary fuel...

40 CFR 60.703 - Monitoring of emissions and operations.

Code of Federal Regulations, 2012 CFR

2012-07-01

... position before any substantial heat exchange is encountered. (ii) Where a catalytic incinerator is used... equipment: (1) A heat sensing device, such as an ultraviolet beam sensor or thermocouple, at the pilot light... 44 MW (150 million Btu/hr) design heat input capacity. Any vent stream introduced with primary fuel...

40 CFR 60.703 - Monitoring of emissions and operations.

Code of Federal Regulations, 2010 CFR

2010-07-01

... position before any substantial heat exchange is encountered. (ii) Where a catalytic incinerator is used... equipment: (1) A heat sensing device, such as an ultraviolet beam sensor or thermocouple, at the pilot light... 44 MW (150 million Btu/hr) design heat input capacity. Any vent stream introduced with primary fuel...

Measurement of heat load density profile on acceleration grid in MeV-class negative ion accelerator.

PubMed

Hiratsuka, Junichi; Hanada, Masaya; Kojima, Atsushi; Umeda, Naotaka; Kashiwagi, Mieko; Miyamoto, Kenji; Yoshida, Masafumi; Nishikiori, Ryo; Ichikawa, Masahiro; Watanabe, Kazuhiro; Tobari, Hiroyuki

2016-02-01

To understand the physics of the negative ion extraction/acceleration, the heat load density profile on the acceleration grid has been firstly measured in the ITER prototype accelerator where the negative ions are accelerated to 1 MeV with five acceleration stages. In order to clarify the profile, the peripheries around the apertures on the acceleration grid were separated into thermally insulated 34 blocks with thermocouples. The spatial resolution is as low as 3 mm and small enough to measure the tail of the beam profile with a beam diameter of ∼16 mm. It was found that there were two peaks of heat load density around the aperture. These two peaks were also clarified to be caused by the intercepted negative ions and secondary electrons from detailed investigation by changing the beam optics and gas density profile. This is the first experimental result, which is useful to understand the trajectories of these particles.

Effect of the focal plane position on CO2 laser beam cutting of injection molded polycarbonate sheets

NASA Astrophysics Data System (ADS)

Moradi, Mahmoud; Mehrabi, Omid; Azdast, Taher; Benyounis, Khaled Y.

2016-11-01

In the present research, the effect of laser beam focal plane position (FPP) on the kerf quality of the polycarbonate laser cutting is investigated. Low power CO2 laser is used as the heat source of the cutting runs. In the experiments, FPP is varied from 0 to -4mm while other processing parameters (i.e. laser power, cutting speed and gas pressure) are considered constant. Upper and lower kerf width, kerf taper, upper heat affected zone and surface roughness of the kerf wall are also considered as the responses. Observations signified that reducing the position of the laser beam focal point from zero to - 3mm reduces the upper and lower kerf width. However reducing FPP below -3mm leads to an increase in the kerf width. Results also reveals that upper heat affected zone value reduces by reduction in FPP. Moreover the best kerf wall surface roughness occurred at FPP= -3mm.

Structural characterization and gas reactions of small metal particles by high-resolution TEM and TED

NASA Technical Reports Server (NTRS)

Heinemann, K.

1985-01-01

The interaction of 100 and 200 keV electron beams with amorphous alumina, titania, and aluminum nitride substrates and nanometer-size palladium particulate deposits was investigated for the two extreme cases of (1) large-area electron-beam flash-heating and (2) small-area high-intensity electron-beam irradiation. The former simulates a short-term heating effect with minimum electron irradiation exposure, the latter simulates high-dosage irradiation with minimum heating effect. All alumina and titania samples responded to the flash-heating treatment with significant recrystallization. However, the size, crystal structure, shape, and orientation of the grains depended on the type and thickness of the films and the thickness of the Pd deposit. High-dosage electron irradiation also readily crystallized the alumina substrate films but did not affect the titania films. The alumina recrystallization products were usually either all in the alpha phase, or they were a mixture of small grains in a number of low-temperature phases including gamma, delta, kappa, beta, theta-alumina. Palladium deposits reacted heavily with the alumina substrates during either treatment, but they were very little effected when supported on titania. Both treatments had the same, less prominent localized crystallization effect on aluminum nitride films.

Brazing copper to dispersion-strengthened copper

NASA Astrophysics Data System (ADS)

Ryding, David G.; Allen, Douglas; Lee, Richard H.

1996-11-01

The advanced photon source is a state-of-the-art synchrotron light source that will produce intense x-ray beams, which will allow the study of smaller samples and faster reactions and processes at a greater level of detail than has ben possible to date. The beam is produced by using third- generation insertion devices in a 7-GeV electron/positron storage ring that is 1,104 meters in circumference. The heat load from these intense high-power devices is very high, and certain components must sustain total heat loads of 3 to 15 kW and heat fluxes of 30 W/mm$_2). Because the beams will cycle on and off many times, thermal shock and fatigue will be a problem. High heat flux impinging on a small area causes a large thermal gradient that results in high stress. GlidCop, a dispersion-strengthened copper, is the desired design material because of its high thermal conductivity and superior mechanical properties as compared to copper and its alloys. GlidCop is not amenable to joining by fusion welding, and brazing requires diligence because of high diffusivity. Brazing procedures were developed using optical and scanning electron microscopy.

Progress on the Development of the Next Generation X-ray Beam Position Monitors at the Advanced Photon Source

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, S.H.; Yang, B.X.; Decker, G.

Accurate and stable x-ray beam position monitors (XBPMs) are ke y elements in obtaining the desired user beam stability in the Advanced Photon Source (APS). The next generat ion XBPMs for high heat load front ends (HHL FEs) have been designed to meet these requirements by utilizing Cu K-edge x-ray fluorescence (XRF) from a pair of copper absorbers and have been installed at the front ends (FEs) of the APS. Com missioning data showed a significant performance improvement over the existing photoemission-based XBPMs. While a similar design concept can be applied for the canted undulator front ends, where two undulatormore » beams are separated by 1.0-mrad, the lower beam power (< 10 kW) per undulator allows us to explore lower-cost solutions based on Compton scat tering from the diamond blades placed edge-on to the x- ray beam. A prototype of the Compton scattering XBPM system was i nstalled at 24-ID-A in May 2015. In this report, the design and test results for XRF-based XBPM and Compton scattering based XBPM are presented. Ongoing research related to the development of the next generation XBPMs on thermal contac t resistance of a joint between two solid bodies is also discussed« less

Progress on the development of the next generation x-ray beam position monitors at the advanced photon source

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, S. H., E-mail: shlee@aps.anl.gov; Yang, B. X., E-mail: bxyang@aps.anl.gov; Decker, G., E-mail: decker@aps.anl.gov

Accurate and stable x-ray beam position monitors (XBPMs) are key elements in obtaining the desired user beam stability in the Advanced Photon Source (APS). The next generation XBPMs for high heat load front ends (HHL FEs) have been designed to meet these requirements by utilizing Cu K-edge x-ray fluorescence (XRF) from a pair of copper absorbers and have been installed at the front ends (FEs) of the APS. Commissioning data showed a significant performance improvement over the existing photoemission-based XBPMs. While a similar design concept can be applied for the canted undulator front ends, where two undulator beams are separatedmore » by 1.0-mrad, the lower beam power (< 10 kW) per undulator allows us to explore lower-cost solutions based on Compton scattering from the diamond blades placed edge-on to the x-ray beam. A prototype of the Compton scattering XBPM system was installed at 24-ID-A in May 2015. In this report, the design and test results for XRF-based XBPM and Compton scattering based XBPM are presented. Ongoing research related to the development of the next generation XBPMs on thermal contact resistance of a joint between two solid bodies is also discussed.« less

Staging of RF-accelerating Units in a MEMS-based Ion Accelerator

NASA Astrophysics Data System (ADS)

Persaud, A.; Seidl, P. A.; Ji, Q.; Feinberg, E.; Waldron, W. L.; Schenkel, T.; Ardanuc, S.; Vinayakumar, K. B.; Lal, A.

Multiple Electrostatic Quadrupole Array Linear Accelerators (MEQALACs) provide an opportunity to realize compact radio- frequency (RF) accelerator structures that can deliver very high beam currents. MEQALACs have been previously realized with acceleration gap distances and beam aperture sizes of the order of centimeters. Through advances in Micro-Electro-Mechanical Systems (MEMS) fabrication, MEQALACs can now be scaled down to the sub-millimeter regime and batch processed on wafer substrates. In this paper we show first results from using three RF stages in a compact MEMS-based ion accelerator. The results presented show proof-of-concept with accelerator structures formed from printed circuit boards using a 3 × 3 beamlet arrangement and noble gas ions at 10 keV. We present a simple model to describe the measured results. We also discuss some of the scaling behaviour of a compact MEQALAC. The MEMS-based approach enables a low-cost, highly versatile accelerator covering a wide range of currents (10 μA to 100 mA) and beam energies (100 keV to several MeV). Applications include ion-beam analysis, mass spectrometry, materials processing, and at very high beam powers, plasma heating.

Direct nanopatterning of polymer/silver nanoblocks under low energy electron beam irradiation.

PubMed

El Mel, Abdel-Aziz; Stephant, Nicolas; Gautier, Romain

2016-10-06

In this communication, we report on the growth, direct writing and nanopatterning of polymer/silver nanoblocks under low energy electron beam irradiation using a scanning electron microscope. The nanoblocks are produced by placing a droplet of an ethylene glycol solution containing silver nitrate and polyvinylpyrrolidone diluted in ethanol directly on a hot substrate heated up to 150 °C. Upon complete evaporation of the droplet, nanospheres, nano- and micro-triangles and nanoblocks made of silver-containing polymers, form over the substrate surface. Considering the nanoblocks as a model system, we demonstrate that such nanostructures are extremely sensitive to the e-beam extracted from the source of a scanning electron microscope operating at low acceleration voltages (between 5 and 7 kV). This sensitivity allows us to efficiently create various nanopatterns (e.g. arrays of holes, oblique slits and nanotrenches) in the material under e-beam irradiation. In addition to the possibility of writing, the nanoblocks revealed a self-healing ability allowing them to recover a relatively smooth surface after etching. Thanks to these properties, such nanomaterials can be used as a support for data writing and erasing on the nanoscale under low energy electron beam irradiation.

Laser-guided, intersecting discharge channels for the final beam transport in heavy-ion fusion

NASA Astrophysics Data System (ADS)

Niemann, C.; Neff, S.; Tauschwitz, A.; Penache, D.; Birkner, R.; Constantin, C.; Knobloch, R.; Presura, R.; Rosmej, F. B.; Hoffmann, D. H. H.; Yu, S. S.

2003-06-01

Ion-beam transport in space charge neutralizing discharge channels has been proposed for the final focus and chamber transport in a heavy-ion fusion reactor. A driver scenario with two-sided target illumination requires a system of two intersecting discharges to transport beams of the same charge from opposite sides towards the fusion target. In this article we report on experiments on the creation of free-standing, intersecting high-current discharge channels. The discharges are initiated in ammonia gas (NH3) in a metallic chamber by two perpendicular CO2-laser beams, which resonantly heat and subsequently rarefy the gas along the laser paths before the breakdown. These low density channels guide the discharges along the predefined paths and also around the 90° angles without any mechanical guiding structures. In this way stable X-, T-, and L-shaped discharges with currents in excess of 40 kA, at pressures of a few mbar were created with a total length of 110 cm. An 11.4 A MeV 58Ni+12 beam from the UNILAC (Universal Linear Accelerator) linear accelerator was used to probe the line-integrated ion-optical properties of the central channel in a T-shaped discharge.

Staging of RF-accelerating Units in a MEMS-based Ion Accelerator

DOE PAGES

Persaud, A.; Seidl, P. A.; Ji, Q.; ...

2017-10-26

Multiple Electrostatic Quadrupole Array Linear Accelerators (MEQALACs) provide an opportunity to realize compact radio- frequency (RF) accelerator structures that can deliver very high beam currents. MEQALACs have been previously realized with acceleration gap distances and beam aperture sizes of the order of centimeters. Through advances in Micro-Electro-Mechanical Systems (MEMS) fabrication, MEQALACs can now be scaled down to the sub-millimeter regime and batch processed on wafer substrates. In this paper we show first results from using three RF stages in a compact MEMS-based ion accelerator. The results presented show proof-of-concept with accelerator structures formed from printed circuit boards using a 3more » × 3 beamlet arrangement and noble gas ions at 10 keV. We present a simple model to describe the measured results. We also discuss some of the scaling behaviour of a compact MEQALAC. The MEMS-based approach enables a low-cost, highly versatile accelerator covering a wide range of currents (10 μA to 100 mA) and beam energies (100 keV to several MeV). Applications include ion-beam analysis, mass spectrometry, materials processing, and at very high beam powers, plasma heating.« less

Staging of RF-accelerating Units in a MEMS-based Ion Accelerator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Persaud, A.; Seidl, P. A.; Ji, Q.

Multiple Electrostatic Quadrupole Array Linear Accelerators (MEQALACs) provide an opportunity to realize compact radio- frequency (RF) accelerator structures that can deliver very high beam currents. MEQALACs have been previously realized with acceleration gap distances and beam aperture sizes of the order of centimeters. Through advances in Micro-Electro-Mechanical Systems (MEMS) fabrication, MEQALACs can now be scaled down to the sub-millimeter regime and batch processed on wafer substrates. In this paper we show first results from using three RF stages in a compact MEMS-based ion accelerator. The results presented show proof-of-concept with accelerator structures formed from printed circuit boards using a 3more » × 3 beamlet arrangement and noble gas ions at 10 keV. We present a simple model to describe the measured results. We also discuss some of the scaling behaviour of a compact MEQALAC. The MEMS-based approach enables a low-cost, highly versatile accelerator covering a wide range of currents (10 μA to 100 mA) and beam energies (100 keV to several MeV). Applications include ion-beam analysis, mass spectrometry, materials processing, and at very high beam powers, plasma heating.« less

The effect of electron cyclotron heating on density fluctuations at ion and electron scales in ITER baseline scenario discharges on the DIII-D tokamak

NASA Astrophysics Data System (ADS)

Marinoni, A.; Pinsker, R. I.; Porkolab, M.; Rost, J. C.; Davis, E. M.; Burrell, K. H.; Candy, J.; Staebler, G. M.; Grierson, B. A.; McKee, G. R.; Rhodes, T. L.; The DIII-D Team

2017-12-01

Experiments simulating the ITER baseline scenario on the DIII-D tokamak show that torque-free pure electron heating, when coupled to plasmas subject to a net co-current beam torque, affects density fluctuations at electron scales on a sub-confinement time scale, whereas fluctuations at ion scales change only after profiles have evolved to a new stationary state. Modifications to the density fluctuations measured by the phase contrast imaging diagnostic (PCI) are assessed by analyzing the time evolution following the switch-off of electron cyclotron heating (ECH), thus going from mixed beam/ECH to pure neutral beam heating at fixed βN . Within 20 ms after turning off ECH, the intensity of fluctuations is observed to increase at frequencies higher than 200 kHz in contrast, fluctuations at lower frequency are seen to decrease in intensity on a longer time scale, after other equilibrium quantities have evolved. Non-linear gyro-kinetic modeling at ion and electron scales scales suggest that, while the low frequency response of the diagnostic is consistent with the dominant ITG modes being weakened by the slow-time increase in flow shear, the high frequency response is due to prompt changes to the electron temperature profile that enhance electron modes and generate a larger heat flux and an inward particle pinch. These results suggest that electron heated regimes in ITER will feature multi-scale fluctuations that might affect fusion performance via modifications to profiles.

Rapid heating of matter using high power lasers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bang, Woosuk

2016-04-08

This slide presentation describes motivation (uniform and rapid heating of a target, opportunity to study warm dense matter, study of nuclear fusion reactions), rapid heating of matter with intense laser-driven ion beams, visualization of the expanding warm dense gold and diamond, and nuclear fusion experiments using high power lasers (direct heating of deuterium spheres (radius ~ 10nm) with an intense laser pulse.

The Experimental Breeder Reactor II seismic probabilistic risk assessment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Roglans, J; Hill, D J

1994-02-01

The Experimental Breeder Reactor II (EBR-II) is a US Department of Energy (DOE) Category A research reactor located at Argonne National Laboratory (ANL)-West in Idaho. EBR-II is a 62.5 MW-thermal Liquid Metal Reactor (LMR) that started operation in 1964 and it is currently being used as a testbed in the Integral Fast Reactor (IFR) Program. ANL has completed a Level 1 Probabilistic Risk Assessment (PRA) for EBR-II. The Level 1 PRA for internal events and most external events was completed in June 1991. The seismic PRA for EBR-H has recently been completed. The EBR-II reactor building contains the reactor, themore » primary system, and the decay heat removal systems. The reactor vessel, which contains the core, and the primary system, consisting of two primary pumps and an intermediate heat exchanger, are immersed in the sodium-filled primary tank, which is suspended by six hangers from a beam support structure. Three systems or functions in EBR-II were identified as the most significant from the standpoint of risk of seismic-induced fuel damage: (1) the reactor shutdown system, (2) the structural integrity of the passive decay heat removal systems, and (3) the integrity of major structures, like the primary tank containing the reactor that could threaten both the reactivity control and decay heat removal functions. As part of the seismic PRA, efforts were concentrated in studying these three functions or systems. The passive safety response of EBR-II reactor -- both passive reactivity shutdown and passive decay heat removal, demonstrated in a series of tests in 1986 -- was explicitly accounted for in the seismic PRA as it had been included in the internal events assessment.« less

Comparison of Sheath Power Transmission Factor for Neutral Beam Injection and Electron Cyclotron Heated Discharges in DIII-D

NASA Astrophysics Data System (ADS)

Donovan, D. C.; Buchenauer, D. A.; Watkins, J. G.; Leonard, A. W.; Lasnier, C. J.; Stangeby, P. C.

2011-10-01

The sheath power transmission factor (SPTF) is examined in DIII-D with a new IR camera, a more thermally robust Langmuir probe array, fast thermocouples, and a unique probe configuration on the Divertor Materials Evaluation System (DiMES). Past data collected from the fixed Langmuir Probes and Infrared Camera on DIII-D have indicated a SPTF near 1 at the strike point. Theory indicates that the SPTF should be approximately 7 and cannot be less than 5. SPTF values are calculated using independent measurements from the IR camera and fast thermocouples. Experiments have been performed with varying levels of electron cyclotron heating and neutral beam power. The ECH power does not involve fast ions, so the SPTF can be calculated and compared to previous experiments to determine the extent to which fast ions may be influencing the SPTF measurements, and potentially offer insight into the disagreement with the theory. Work supported in part by US DOE under DE-AC04-94AL85000, DE-FC02-04ER54698, and DE-AC52-07NA27344.

Slowing techniques for loading a magneto-optical trap of CaF molecules

NASA Astrophysics Data System (ADS)

Truppe, Stefan; Fitch, Noah; Williams, Hannah; Hambach, Moritz; Sauer, Ben; Hinds, Ed; Tarbutt, Mike

2016-05-01

Ultracold molecules in a magneto-optical trap (MOT) are useful for testing fundamental physics and studying strongly-interacting quantum systems. With experiments starting with a relatively fast (50-200 m/s) buffer-gas beam, a primary concern is decelerating molecules to below the MOT capture velocity, typically 10 m/s. Direct laser cooling, where the molecules are slowed via momentum transfer from a chirped counter-propagating narrowband laser, is a natural choice. However, chirping the cooling and repump lasers requires precise control of multiple laser frequencies simultaneously. Another approach, called ``white-light slowing'' uses a broadband laser such that all fast molecules in the beam are decelerated. By addressing numerous velocities no chirping is needed. Unfortunately, both techniques have significant losses as molecules are transversely heated during the optical cycling. Ideally, the slowing method would provide simultaneous deceleration and transverse guiding. A newly developed technique, called Zeeman-Sisyphus deceleration, is potentially capable of both. Using permanent magnets and optical pumping, the number of scattered photons is reduced, lessening transverse heating and relaxing the repump requirements. Here we compare all three options for CaF.

First neutral beam injection experiments on KSTAR tokamak.

PubMed

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

2012-02-01

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

Study of neutron generation in the compact tokamak TUMAN-3M in support of a tokamak-based fusion neutron source

NASA Astrophysics Data System (ADS)

Kornev, V. A.; Askinazi, L. G.; Belokurov, A. A.; Chernyshev, F. V.; Lebedev, S. V.; Melnik, A. D.; Shabelsky, A. A.; Tukachinsky, A. S.; Zhubr, N. A.

2017-12-01

The paper presents DD neutron flux measurements in neutron beam injection (NBI) experiments aimed at the optimization of target plasma and heating beam parameters to achieve maximum neutron flux in the TUMAN-3M compact tokamak. Two ion sources of different design were used, which allowed the separation of the beam’s energy and power influence on the neutron rate. Using the database of experiments performed with the two ion sources, an empirical scaling was derived describing the neutron rate dependence on the target plasma and heating beam parameters. Numerical modeling of the neutron rate in the NBI experiments performed using the ASTRA transport code showed good agreement with the scaling.

Beam heated linear theta-pinch device for producing hot plasmas

DOEpatents

Bohachevsky, Ihor O.

1981-01-01

A device for producing hot plasmas comprising a single turn theta-pinch coil, a fast discharge capacitor bank connected to the coil, a fuel element disposed along the center axis of the coil, a predetermined gas disposed within the theta-pinch coil, and a high power photon, electron or ion beam generator concentrically aligned to the theta-pinch coil. Discharge of the capacitor bank generates a cylindrical plasma sheath within the theta-pinch coil which heats the outer layer of the fuel element to form a fuel element plasma layer. The beam deposits energy in either the cylindrical plasma sheath or the fuel element plasma layer to assist the implosion of the fuel element to produce a hot plasma.

Method and apparatus for simulating atomospheric absorption of solar energy due to water vapor and CO.sub.2

DOEpatents

Sopori, Bhushan L.

1995-01-01

A method and apparatus for improving the accuracy of the simulation of sunlight reaching the earth's surface includes a relatively small heated chamber having an optical inlet and an optical outlet, the chamber having a cavity that can be filled with a heated stream of CO.sub.2 and water vapor. A simulated beam comprising infrared and near infrared light can be directed through the chamber cavity containing the CO.sub.2 and water vapor, whereby the spectral characteristics of the beam are altered so that the output beam from the chamber contains wavelength bands that accurately replicate atmospheric absorption of solar energy due to atmospheric CO.sub.2 and moisture.

Method and apparatus for simulating atmospheric absorption of solar energy due to water vapor and CO{sub 2}

DOEpatents

Sopori, B.L.

1995-06-20

A method and apparatus for improving the accuracy of the simulation of sunlight reaching the earth`s surface includes a relatively small heated chamber having an optical inlet and an optical outlet, the chamber having a cavity that can be filled with a heated stream of CO{sub 2} and water vapor. A simulated beam comprising infrared and near infrared light can be directed through the chamber cavity containing the CO{sub 2} and water vapor, whereby the spectral characteristics of the beam are altered so that the output beam from the chamber contains wavelength bands that accurately replicate atmospheric absorption of solar energy due to atmospheric CO{sub 2} and moisture. 8 figs.

Real-time control system for adaptive resonator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Flath, L; An, J; Brase, J

2000-07-24

Sustained operation of high average power solid-state lasers currently requires an adaptive resonator to produce the optimal beam quality. We describe the architecture of a real-time adaptive control system for correcting intra-cavity aberrations in a heat capacity laser. Image data collected from a wavefront sensor are processed and used to control phase with a high-spatial-resolution deformable mirror. Our controller takes advantage of recent developments in low-cost, high-performance processor technology. A desktop-based computational engine and object-oriented software architecture replaces the high-cost rack-mount embedded computers of previous systems.

Prediction of Experimental Surface Heat Flux of Thin Film Gauges using ANFIS

NASA Astrophysics Data System (ADS)

Sarma, Shrutidhara; Sahoo, Niranjan; Unal, Aynur

2018-05-01

Precise quantification of surface heat fluxes in highly transient environment is of paramount importance from the design point of view of several engineering equipment like thermal protection or cooling systems. Such environments are simulated in experimental facilities by exposing the surface with transient heat loads typically step/impulsive in nature. The surface heating rates are then determined from highly transient temperature history captured by efficient surface temperature sensors. The classical approach is to use thin film gauges (TFGs) in which temperature variations are acquired within milliseconds, thereby allowing calculation of surface heat flux, based on the theory of one-dimensional heat conduction on a semi-infinite body. With recent developments in the soft computing methods, the present study is an attempt for the application of intelligent system technique, called adaptive neuro fuzzy inference system (ANFIS) to recover surface heat fluxes from a given temperature history recorded by TFGs without having the need to solve lengthy analytical equations. Experiments have been carried out by applying known quantity of `impulse heat load' through laser beam on TFGs. The corresponding voltage signals have been acquired and surface heat fluxes are estimated through classical analytical approach. These signals are then used to `train' the ANFIS model, which later predicts output for `test' values. Results from both methods have been compared and these surface heat fluxes are used to predict the non-linear relationship between thermal and electrical properties of the gauges that are exceedingly pertinent to the design of efficient TFGs. Further, surface plots have been created to give an insight about dimensionality effect of the non-linear dependence of thermal/electrical parameters on each other. Later, it is observed that a properly optimized ANFIS model can predict the impulsive heat profiles with significant accuracy. This paper thus shows the appropriateness of soft computing technique as a practically constructive replacement for tedious analytical formulation and henceforth, effectively quantifies the modeling of TFGs.

Overview of the design of the ITER heating neutral beam injectors

NASA Astrophysics Data System (ADS)

Hemsworth, R. S.; Boilson, D.; Blatchford, P.; Dalla Palma, M.; Chitarin, G.; de Esch, H. P. L.; Geli, F.; Dremel, M.; Graceffa, J.; Marcuzzi, D.; Serianni, G.; Shah, D.; Singh, M.; Urbani, M.; Zaccaria, P.

2017-02-01

The heating neutral beam injectors (HNBs) of ITER are designed to deliver 16.7 MW of 1 MeV D0 or 0.87 MeV H0 to the ITER plasma for up to 3600 s. They will be the most powerful neutral beam (NB) injectors ever, delivering higher energy NBs to the plasma in a tokamak for longer than any previous systems have done. The design of the HNBs is based on the acceleration and neutralisation of negative ions as the efficiency of conversion of accelerated positive ions is so low at the required energy that a realistic design is not possible, whereas the neutralisation of H- and D- remains acceptable (≈56%). The design of a long pulse negative ion based injector is inherently more complicated than that of short pulse positive ion based injectors because: • negative ions are harder to create so that they can be extracted and accelerated from the ion source; • electrons can be co-extracted from the ion source along with the negative ions, and their acceleration must be minimised to maintain an acceptable overall accelerator efficiency; • negative ions are easily lost by collisions with the background gas in the accelerator; • electrons created in the extractor and accelerator can impinge on the extraction and acceleration grids, leading to high power loads on the grids; • positive ions are created in the accelerator by ionisation of the background gas by the accelerated negative ions and the positive ions are back-accelerated into the ion source creating a massive power load to the ion source; • electrons that are co-accelerated with the negative ions can exit the accelerator and deposit power on various downstream beamline components. The design of the ITER HNBs is further complicated because ITER is a nuclear installation which will generate very large fluxes of neutrons and gamma rays. Consequently all the injector components have to survive in that harsh environment. Additionally the beamline components and the NB cell, where the beams are housed, will be activated and all maintenance will have to be performed remotely. This paper describes the design of the HNB injectors, but not the associated power supplies, cooling system, cryogenic system etc, or the high voltage bushing which separates the vacuum of the beamline from the high pressure SF6 of the high voltage (1 MV) transmission line, through which the power, gas and cooling water are supplied to the beam source. Also the magnetic field reduction system is not described.

Cooling options for high-average-power laser mirrors

NASA Astrophysics Data System (ADS)

Vojna, D.; Slezak, O.; Lucianetti, A.; Mocek, T.

2015-01-01

Thermally-induced deformations of steering mirrors reflecting 100 J/10 Hz laser pulses in vacuum have been analyzed. This deformation is caused by the thermal stress arisen due to parasitic absorption of 1 kW square-shaped flat-top laser beam in the dielectric multi-layer structure. Deformation depends on amount of absorbed power and geometry of the mirror as well as on the heat removal scheme. In our calculations, the following percentages of absorption of the incident power have been used: 1%, 0.5% and 0.1%. The absorbed power has been considered to be much higher than that expected in reality to assess the worst case scenario. Rectangular and circular mirrors made of zerodur (low thermal expansion glass) were considered for these simulations. The effect of coating layers on induced deformations has been neglected. Induced deformation of the mirror surface can significantly degrade the quality of the laser beam in the beam delivery system. Therefore, the proper design of the cooling scheme for the mirror in order to minimize the deformations is needed. Three possible cooling schemes of the mirror have been investigated. The first one takes advantage of a radiation cooling of the mirror and a copper heatsink fixed to the rear face of the mirror, the second scheme is based on additional heat conduction provided by flexible copper wires connected to the mirror holder, and the last scheme combines two above mentioned methods.

Deuteron Beam Driven Fast Ignition of a Pre-Compressed Inertial Confinement Fusion (ICF) Fuel Capsule

NASA Astrophysics Data System (ADS)

Yang, Xiaoling; Miley, George; Flippo, Kirk; Hora, Heinrich; Gaillard, Sandrine; Offermann, Dustin

2012-10-01

We proposed to utilize a new ``Deuterium Cluster'' type structure for the laser interaction foil to generate an energetic deuteron beam as the fast igniter to ignite inertial confinement fusion fuel capsule. The benefit of deuteron beam driven fast ignition is that its deposition in the target fuel will not only provide heating but also fuse with fuel as they slow down in the target. The preliminary results from recent laser-deuteron acceleration experiment at LANL were encouraging. Also, in most recent calculations, we found that a 12.73% extra energy gain from deuteron beam-target fusion could be achieved when quasi-Maxwellian deuteron beam was assumed, and when a ρrb = 4.5 g/cm2 was considered, where ρ is the fuel density, and rb is the ion beam focusing radius on the target. These results provide some insight into the contribution of the extra heat produced by deuteron beam-target fusion to the hot spot ignition process. If the physics works as anticipated, this novel type of interaction foil can efficiently generate energetic deuterons during intense laser pulses. The massive yield of deuterons should turn out to be the most efficient way of igniting the DT fuel, making the dream of near-term commercialization of FI fusion more achievable.

Measuring and analyzing thermal deformations of the primary reflector of the Tianma radio telescope

NASA Astrophysics Data System (ADS)

Dong, Jian; Fu, Li; Liu, Qinghui; Shen, Zhiqiang

2018-06-01

The primary reflector of the Tianma Radio Telescope (TMRT) distorts due to the varying thermal conditions, which dramatically reduces the aperture efficiency of Q-band observations. To evaluate and overcome the thermal effects, a thermal deformations measurement system has been established based on the extended Out-of-Focus holography (e-OOF). The thermal deformations can be measured in approximately 20 min with an illumination-weighted surface root mean square (RMS) accuracy of approximately 50 μm. We have measured the thermal deformations when the backup and front structure were heated by the sun respectively, and used the active surface system to correct the thermal deformations immediately to confirm the measurements. The thermal deformations when the backup structure is heated are larger than those when the front structure is heated. The values of half power beam width (HPBW) are related to the illumination-weighted surface RMS, and can be used to check the thermal deformations. When the backup structure is heated, the aperture efficiencies can remain above 90% of the maximum efficiency at 40 GHz for approximately two hours after one adjustment. While the front structure is heated, the aperture efficiencies can remain above 90% of the maximum efficiency at 40 GHz, and above 95% after one adjustment in approximately three hours.

Radiation effects program

NASA Astrophysics Data System (ADS)

1985-09-01

No existing LINAC Based Beam Heating facility comes within a factor of ten of the needs of a high heating rate thermodynamic properties research facility. The facility could be built at the Naval Research Lab. for a cost in the neighborhood of 2 million dollars. The 10 MeV electron beam would not produce any serious radioactivity but would provide unprecedented beam power for such other applications as food processing, sewer treatment, materials curing, radiation hardness assurance, etc. One can always achieve lower current densities by scattering the beam and moving the device under test further away from the scatterer. In this case one must rely on the TLD readings to indicate the dose rate at the point of interest. For general utility with the beam covering about four TLD's fairly evenly one can claim that the NRL LINAC can produce a maximum dose rate of about 6 x 10 to the 10th power rads (Si) per second for a pulse length of 1.5 microseconds, and about 1.4 x 10 to the 11th power rads (Si) per second in a 50 nanosecond pulse. In both cases the beam area is about 0.4 square centimeters.

On neutral-beam injection counter to the plasma current

DOE Office of Scientific and Technical Information (OSTI.GOV)

Helander, P.; Akers, R.J.; Eriksson, L.-G.

2005-11-15

It is well known that when neutral beams inject ions into trapped orbits in a tokamak, the transfer of momentum between the beam and the plasma occurs through the torque exerted by a radial return current. It is shown that this implies that the angular momentum transferred to the plasma can be larger than the angular momentum of the beam, if the injection is in the opposite direction to the plasma current and the beam ions suffer orbit losses. On the Mega-Ampere Spherical Tokamak (MAST) [R. J. Akers, J. W. Ahn, G. Y. Antar, L. C. Appel, D. Applegate, C.more » Brickley et al., Plasma Phys. Controlled Fusion 45, A175 (2003)], this results in up to 30% larger momentum deposition with counterinjection than with co-injection, with substantially increased plasma rotation as a result. It is also shown that heating of the plasma (most probably of the ions) can occur even when the beam ions are lost before they have had time to slow down in the plasma. This is the dominant heating mechanism in the outer 40% of the MAST plasma during counterinjection.« less

Thomson scattering diagnostic on the Compact Toroidal Hybrid Experiment

NASA Astrophysics Data System (ADS)

Traverso, Peter; Maurer, D. A.; Ennis, D. A.; Hartwell, G. J.

2016-10-01

A Thomson scattering system is being commissioned for the non-axisymmetric plasmas of the Compact Toroidal Hybrid (CTH), a five-field period current-carrying torsatron. The system takes a single point measurement at the magnetic axis to both calibrate the two- color soft x-ray Te system and serve as an additional diagnostic for the V3FIT 3D equilibrium reconstruction code. A single point measurement will reduce the uncertainty in the reconstructed peak pressure by an order of magnitude for both current-carrying plasmas and future gyrotron-heated stellarator plasmas. The beam, generated by a frequency doubled Continuum 2 J, Nd:YaG laser, is passed vertically through an entrance Brewster window and a two-aperture optical baffle system to minimize stray light. The beam line propagates 8 m to the CTH device mid-plane with the beam diameter < 3 mm inside the plasma volume. Thomson scattered light is collected by two adjacent f/2 plano-convex condenser lenses and focused onto a custom fiber bundle. The fiber is then re-bundled and routed to a Holospec f/1.8 spectrograph to collect the red-shifted scattered light from 535-565 nm. The system has been designed to measure plasmas with core Te of 100 to 200 eV and densities of 5 ×1018 to 5 ×1019 m-3. Work supported by USDOE Grant DE-FG02-00ER54610.

Finite Element Analysis of High Heat Load Deformation and Mechanical Bending Correction of a Beamline Mirror for the APS Upgrade

NASA Astrophysics Data System (ADS)

Goldring, Nicholas

The impending Advanced Photon Source Upgrade (APS-U) will introduce a hard x-ray source that is set to surpass the current APS in brightness and coherence by two to three orders of magnitude. To achieve this, the storage ring light source will be equipped with a multi-bend achromat (MBA) lattice. In order to fully exploit and preserve the integrity of new beams actualized by upgraded storage ring components, improved beamline optics must also be introduced. The design process of new optics for the APS-U and other fourth generation synchrotrons involves the challenge of accommodating unprecedented heat loads. This dissertation presents an ex-situ analysis of heat load deformation and the subsequent mechanical bending correction of a 400 mm long, grazing-incidence, H2O side-cooled, reflecting mirror subjected to x-ray beams produced by the APS-U undulator source. Bending correction is measured as the smallest rms slope error, sigmarms, that can be resolved over a given length of the heat deformed geometry due to mechanical bending. Values of sigmarms in the <0.1 microrad regime represent a given mirror length over which incident x-ray beams from modern sources can be reflected without significant loss of quality. This study assumes a perfectly flat mirror surface and does not account for finish errors or other contributions to sigmarms beyond the scope of thermal deformation and elastic bending. The methodology of this research includes finite element analysis (FEA) employed conjointly with an analytical solution for mechanical bending deflection by means of an end couple. Additionally, the study will focus on two beam power density profiles predicted by the APS-U which were created using the software SRCalc. The profiles account for a 6 GeV electron beam with second moment widths of 0.058 and 0.011 mm in the x- and y- directions respectively; the electron beam is passed through a 4.8 m long, 28 mm period APS-U undulator which produces the x-ray beam incident at a 3 mrad grazing angle on the flat mirror surface for both cases. The first power density profile is the most extreme case created by the undulator at it's closest gap with a critical energy of 3 keV (k y=2.459); the second profile is generated for the case in which the undulator is tuned to emit at 8 keV (ky=1.026). The 3 keV case is of particular interest as it represents one of the most intense peak heat loads predicted to be incident on first optics at the APS-U. The FEA results revealed that the deflection due to the 3 keV heat load yields a 10.9 microrad rms slope error over the full mirror length. The projected correction via the elastic bending of the substrate yields a 0.10 microrad sigma rms within the center longitudinal 300 mm. The FEA also predicts that the 8 keV heat load deflection can be corrected to a sigma rms of 0.11 microrad within the center 300 mm from 1.50 microrad over the entire length. Attempts to optimize the end couple to correct over the entire 400 mm mirror length were unable to resolve the heat load deflection rms slope error to within a <0.1 microrad value for either case. However, if a larger corrected surface is required, a longer mirror can be implemented so as to absorb the heat load of a larger beam than necessary which can then be cut by an aperture to the desired size and energy range.

Integrated Design of Undepressed Collector for Low Power Gyrotron

NASA Astrophysics Data System (ADS)

Kumar, Anil; Goswami, Uttam K.; Poonia, Sunita; Singh, Udaybir; Kumar, Nitin; Alaria, M. K.; Bera, A.; Khatun, Hasina; Sinha, A. K.

2011-06-01

A 42 GHz, 200 kW continuous wave (CW) gyrotron, operating at TE03 mode is under development for the electron cyclotron resonance plasma heating of the Indian TOKAMAK system. The gyrotron is made up of an undepressed collector. The undepressed collector is simple to design and cost effective. In this paper, a detailed design study of the undepressed collector for the 42 GHz gyrotron is presented. The EGUN code is used to analyze the spent electron beam trajectory for the maximum spread to reduce the power loading on the collector surface. To achieve wall loading ≤1 kW/cm2, a collector with a length of 800 mm and a radius of 42.5 mm is designed. The design also includes the three magnet systems around the collector for maximum and uniform beam spread. The thermal and the structural analyses are done using the ANSYS code to optimize the collector structure and dimensions with tolerance.

Probing spherical tokamak plasmas using charged fusion products

NASA Astrophysics Data System (ADS)

Boeglin, Werner U.; Perez, Ramona V.; Darrow, Douglass S.; Cecconello, Marco; Klimek, Iwona; Allan, Scott Y.; Akers, Rob J.; Jones, Owen M.; Keeling, David L.; McClements, Ken G.; Scannell, Rory

2015-11-01

The detection of charged fusion products, such as protons and tritons resulting from D(d,p)t reactions, can be used to determine the fusion reaction rate profile in large spherical tokamak plasmas with neutral beam heating. The time resolution of a diagnostic of this type makes it possible to study the slowly-varying beam density profile, as well as rapid changes resulting from MHD instabilities. A 4-channel prototype proton detector (PD) was installed and operated on the MAST spherical tokamak in August/September 2013, and a new 6-channel system for the NSTX-U spherical tokamak is under construction. PD and neutron camera measurements obtained on MAST will be compared with TRANSP calculations, and the design of the new NSTX-U system will be presented, together with the first results from this diagnostic, if available. Supported in part by DOE DE-SC0001157.

Feasibility of a motional Stark effect system on the TCV tokamak

DOE Office of Scientific and Technical Information (OSTI.GOV)

Siegrist, M.R.; Hawkes, N.; Weisen, H.

This paper presents a feasibility study for a motional Stark effect (MSE) [F. M. Levinton et al., Phys. Rev. Lett. 63, 2060 (1989)] diagnostic on the TCV tokamak. A numerical simulation code has been used to identify the optimal port arrangement and geometrical layout. It predicts the expected measurement accuracy for a range of typical plasma scenarios. With the existing neutral beam injector (NBI) and a detection system based on current day technology, it should be possible to determine the safety factor with an accuracy of the order of 5%. A vertically injected beam through the plasma center would allowmore » one to measure plasmas which are centered above the midplane, a common occurrence in connection with electron cyclotron resonance heating and electron cyclotron current drive experiments. In this case a new and ideally more powerful NBI would be required.« less

Waveguide detuning caused by transverse magnetic fields on a simulated in-line 6 MV linac.

PubMed

St Aubin, J; Steciw, S; Fallone, B G

2010-09-01

Due to the close proximity of the linear accelerator (linac) to the magnetic resonance (MR) imager in linac-MR systems, it will be subjected to magnet fringe fields larger than the Earth's magnetic field of 5 x 10(-5) T. Even with passive or active shielding designed to reduce these fields, some magnitude of the magnetic field is still expected to intersect the linac, causing electron deflection and beam loss. This beam loss, resulting from magnetic fields that cannot be eliminated with shielding, can cause a detuning of the waveguide due to excessive heating. The detuning, if significant, could lead to an even further decrease in output above what would be expected strictly from electron deflections caused by an external magnetic field. Thus an investigation of detuning was performed through various simulations. According to the Lorentz force, the electrons will be deflected away from their straight course to the target, depositing energy as they impact the linac copper waveguide. The deposited energy would lead to a heating and deformation of the copper structure resulting in resonant frequency changes. PARMELA was used to determine the mean energy and fraction of total beam lost in each linac cavity. The energy deposited into the copper waveguide from the beam losses caused by transverse magnetic fields was calculated using the Monte Carlo program DOSRZnrc. From the total energy deposited, the rise in temperature and ultimately the deformation of the structure was estimated. The deformed structure was modeled using the finite element method program COMSOL MULTIPHYSICS to determine the change in cavity resonant frequency. The largest changes in resonant frequency were found in the first two accelerating cavities for each field strength investigated. This was caused by a high electron fluence impacting the waveguide inner structures coupled with their low kinetic energies. At each field strength investigated, the total change in accelerator frequency was less than a manufacturing tolerance of 10 kHz and is thus not expected to have a noticeable effect on accelerator performance. The amount of beam loss caused by magnetic fringe fields for a linac in a linac-MR system depends on the effectiveness of its magnetic shielding. Despite the best efforts to shield the linac from the magnetic fringe fields, some persistent magnetic field is expected which would result in electron beam loss. This investigation showed that the detuning of the waveguide caused by additional electron beam loss in persistent magnetic fields is not a concern.

Novel, compact, and simple ND:YVO4 laser with 12 W of CW optical output power and good beam quality

NASA Astrophysics Data System (ADS)

Zimer, H.; Langer, B.; Wittrock, U.; Heine, F.; Hildebrandt, U.; Seel, S.; Lange, R.

2017-11-01

We present first, promising experiments with a novel, compact and simple Nd:YVO4 slab laser with 12 W of 1.06 μm optical output power and a beam quality factor M2 2.5. The laser is made of a diffusion-bonded YVO4/Nd:YVO4 composite crystal that exhibits two unique features. First, it ensures a one-dimensional heat removal from the laser crystal, which leads to a temperature profile without detrimental influence on the laser beam. Thus, the induced thermo-optical aberrations to the laser field are low, allowing power scaling with good beam quality. Second, the composite crystal itself acts as a waveguide for the 809 nm pump-light that is supplied from a diode laser bar. Pump-light shaping optics, e.g. fast- or slow-axis collimators can be omitted, reducing the complexity of the system. Pump-light redundancy can be easily achieved. Eventually, the investigated slab laser might be suitable for distortion-free high gain amplification of weak optical signals.

Continuum simulation of heat transfer and solidification behavior of AlSi10Mg in Direct Metal Laser Sintering Process

NASA Astrophysics Data System (ADS)

Ojha, Akash; Samantaray, Mihir; Nath Thatoi, Dhirendra; Sahoo, Seshadev

2018-03-01

Direct Metal Laser Sintering (DMLS) process is a laser based additive manufacturing process, which built complex structures from powder materials. Using high intensity laser beam, the process melts and fuse the powder particles makes dense structures. In this process, the laser beam in terms of heat flux strikes the powder bed and instantaneously melts and joins the powder particles. The partial solidification and temperature distribution on the powder bed endows a high cooling rate and rapid solidification which affects the microstructure of the build part. During the interaction of the laser beam with the powder bed, multiple modes of heat transfer takes place in this process, that make the process very complex. In the present research, a comprehensive heat transfer and solidification model of AlSi10Mg in direct metal laser sintering process has been developed on ANSYS 17.1.0 platform. The model helps to understand the flow phenomena, temperature distribution and densification mechanism on the powder bed. The numerical model takes into account the flow, heat transfer and solidification phenomena. Simulations were carried out for sintering of AlSi10Mg powders in the powder bed having dimension 3 mm × 1 mm × 0.08 mm. The solidification phenomena are incorporated by using enthalpy-porosity approach. The simulation results give the fundamental understanding of the densification of powder particles in DMLS process.

Direct sunlight facility for testing and research in HCPV

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sciortino, Luisa, E-mail: luisa.sciortino@unipa.it; Agnello, Simonpietro, E-mail: luisa.sciortino@unipa.it; Bonsignore, Gaetano

2014-09-26

A facility for testing different components for HCPV application has been developed in the framework of 'Fotovoltaico ad Alta Efficienza' (FAE) project funded by the Sicilian Regional Authority (PO FESR Sicilia 2007/2013 4.1.1.1). The testing facility is equipped with an heliostat providing a wide solar beam inside the lab, an optical bench for mounting and aligning the HCPV components, electronic equipments to characterize the I-V curves of multijunction cells operated up to 2000 suns, a system to circulate a fluid in the heat sink at controlled temperature and flow-rate, a data logging system with sensors to measure temperatures in severalmore » locations and fluid pressures at the inlet and outlet of the heat sink, and a climatic chamber with large test volume to test assembled HCPV modules.« less

The QED engine spectrum - Fusion-electric propulsion for air-breathing to interstellar flight

NASA Technical Reports Server (NTRS)

Bussard, Robert W.; Jameson, Lorin W.

1993-01-01

A new inertial-electrostatic-fusion direct electric power source can be used to drive a relativistic e-beam to heat propellant. The resulting system is shown to yield specific impulse and thrust/mass ratio 2-3 orders of magnitude larger than from other advanced propulsion concepts. This QED system can be applied to aerospace vehicles from air-breathing to near-interstellar flight. Examples are given for Earth/Mars flight missions, that show transit times of 40 d with 20 percent payload in single-stage vehicles.

EFFECT OF HEAT TREATMENT ON (Cr, Fe)7C3/γ-Fe COATINGS IN SITU SYNTHESIZED BY VACUUM ELECTRON BEAM IRRADIATION

NASA Astrophysics Data System (ADS)

Lu, Binfeng; Chen, Yunxia; Xu, Mengjia

(Cr, Fe)7C3/γ-Fe composite layer has been in situ synthesized on a low carbon steel surface by vacuum electron beam VEB irradiation. The synthesized samples were then subdued to different heat treatments to improve their impaired impact toughness. The microstructure, impact toughness and wear resistance of the heat-treated samples were studied by means of optical microscope (OM), X-ray diffraction (XRD), scanning electron microscope (SEM), microhardness tester, impact test machine and tribological tester. After heat treatment, the primary and eutectic carbides remained in their original shape and size, and a large number of secondary carbides precipitated in the iron matrix. Since the Widmanstatten ferrite in the heat affected zone (HAZ) transformed to fine ferrite completely, the impact toughness of the heat-treated samples increased significantly. The microhardness of the heat-treated samples decreased slightly due to the decreased chromium content in the iron matrix. The wear resistance of 1000∘C and 900∘C heat-treated samples was almost same with the as-synthesized sample. While the wear resistance of the 800∘C heat-treated one decreased slightly because part of the austenite matrix had transformed to ferrite matrix, which reduced the bonding of carbides particulates.

5 MV 30 mA industrial electron processing system

NASA Astrophysics Data System (ADS)

Hoshi, Y.; Mizusawa, K.

1991-05-01

Industrial electron beam processing systems have been in use in various application fields such as: improving heat resistivity of wire insulation; controlling quality of automobile rubber tires and melt index characteristics of PE foams; and curing paintings or printing inks. Recently, there has come up a need for electron beam with an energy higher than 3 MV in order to disinfect salmonella in chicken meat, to kill bugs in fruits, and to sterilize medical disposables. To meet this need we developed a 5 MV 30 mA electron processing system with an X-ray conversion target. The machine was tested in NHV's plant in Kyoto at continuous operation of full voltage and full current. It proved to be very steady in operation with a high efficiency (as much as 72%). Also, the X-ray target was tested in a continuous run of 5 MV 30 mA (150 kW). It proved to be viable in industrial utilization. This paper introduces the process and the results of the development.

Design and optimisation of low heat load liquid helium cryostat to house cryogenic current comparator in antiproton decelerator at CERN

NASA Astrophysics Data System (ADS)

Lees, A.; Koettig, T.; Fernandes, M.; Tan, J.

2017-02-01

The Cryogenic Current Comparator (CCC) is installed in the low-energy Antiproton Decelerator (AD) at CERN to make an absolute measurement of the beam intensity. Operating below 4.2 K, it is based on a superconducting quantum interference device (SQUID) and employs a superconducting niobium shield to supress magnetic field components not linked to the beam current. The AD contains no permanent cryogenic infrastructure so the local continuous liquefaction of helium using a pulse-tube is required; limiting the available cooling power to 0.69 W at 4.2K. Due to the sensitivity of the SQUID to variations in magnetic fields, the CCC is highly sensitive to mechanical vibration which is limited to a minimum by the support systems of the cryostat. This article presents the cooling system of the cryostat and discusses the design challenges overcome to minimise the transmission of vibration to the CCC while operating within the cryogenic limits imposed by the cooling system.

Technology Solutions Case Study: Durable Interior Foundation Insulation Retrofits for Cold Climates, Cloquet, Minnesota

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

Thermal and moisture problems in existing basements create a unique challenge as the exterior face of the wall is not easily or inexpensively accessible. This approach by the NorthernSTAR Building America Partnership team addresses thermal and moisture management from the interior face of the wall without disturbing the exterior soil and landscaping. It is effective at reducing energy loss through the wall principally during the heating season. The team conducted experiments at the Cloquet Residential Research Facility to test the heat and moisture performance of four hollow masonry block wall systems and two rim-joist systems. These systems were retrofitted withmore » interior insulation in compliance with the 2012 IECC. The research showed for the first time that, for masonry block walls in a cold climate, a solid bond beam or equivalent provides adequate resistance to moisture transport from a hollow core to the rim-joist cavity. Thus, a solid top course is a minimum requirement for an interior retrofit insulation system.« less

ZnO sublimation using a polyenergetic pulsed electron beam source: numerical simulation and validation

NASA Astrophysics Data System (ADS)

Tricot, S.; Semmar, N.; Lebbah, L.; Boulmer-Leborgne, C.

2010-02-01

This paper details the electro-thermal study of the sublimation phase on a zinc oxide surface. This thermodynamic process occurs when a ZnO target is bombarded by a pulsed electron beam source composed of polyenergetic electrons. The source delivers short pulses of 180 ns of electrons with energies up to 16 keV. The beam total current reaches 800 A and is focused onto a spot area 2 mm in diameter. The Monte Carlo CASINO program is used to study the first stage of the interaction and to define the heat source space distribution inside the ZnO target. Simulation of the second stage of interaction is developed in a COMSOL multiphysics project. The simulated thermal field induced by space and time heat conduction is presented. Typically for a pulsed electron beam 2 mm in diameter of electrons having energies up to 16 keV, the surface temperature reaches a maximum of 7000 K. The calculations are supported by SEM pictures of the target irradiated by various beam energies and numbers of pulses.

Soft X-ray Spectrometer for Characterization of Electron Beam Driven WDM

NASA Astrophysics Data System (ADS)

Ramey, Nicholas; Coleman, Joshua; Perry, John

2017-10-01

A preliminary design study is being performed on a soft X-ray spectrometer to measure K-shell spectra emitted by a warm dense plasma generated by an intense, relativistic electron beam interacting with a thin, low-Z metal foil. A 100-ns-long electron pulse with a beam current of 1.7 kA and energy of 19.8 MeV deposits energy into the thin metal foil heating it to a warm dense plasma. The collisional ionization of the target by the electron beam produces an anisotropic angular distribution of K-shell radiation and a continuum of both scattered electrons and Bremsstrahlung up to the beam energy of 19.8 MeV. A proof-of-principle Bragg-type spectrometer has been built to measure the Ti K- α and K- β lines. The goal of the spectrometer is to measure the temperature and density of this warm dense plasma for the first time with this heating technique. This work was supported by the National Nuclear Security Administration of the U.S. Department of Energy under Contract No. DE-AC52-06NA25396.

Hollow laser plasma self-confined microjet generation

NASA Astrophysics Data System (ADS)

Sizyuk, Valeryi; Hassanein, Ahmed; CenterMaterials under Extreme Environment Team

2017-10-01

Hollow laser beam produced plasma (LPP) devices are being used for the generation of the self-confined cumulative microjet. Most important place by this LPP device construction is achieving of an annular distribution of the laser beam intensity by spot. An integrated model is being developed to detailed simulation of the plasma generation and evolution inside the laser beam channel. The model describes in two temperature approximation hydrodynamic processes in plasma, laser absorption processes, heat conduction, and radiation energy transport. The total variation diminishing scheme in the Lax-Friedrich formulation for the description of plasma hydrodynamic is used. Laser absorption and radiation transport models on the base of Monte Carlo method are being developed. Heat conduction part on the implicit scheme with sparse matrixes using is realized. The developed models are being integrated into HEIGHTS-LPP computer simulation package. The integrated modeling of the hollow beam laser plasma generation showed the self-confinement and acceleration of the plasma microjet inside the laser channel. It was found dependence of the microjet parameters including radiation emission on the hole and beam radiuses ratio. This work is supported by the National Science Foundation, PIRE project.

First results of the ITER-relevant negative ion beam test facility ELISE (invited).

PubMed

Fantz, U; Franzen, P; Heinemann, B; Wünderlich, D

2014-02-01

An important step in the European R&D roadmap towards the neutral beam heating systems of ITER is the new test facility ELISE (Extraction from a Large Ion Source Experiment) for large-scale extraction from a half-size ITER RF source. The test facility was constructed in the last years at Max-Planck-Institut für Plasmaphysik Garching and is now operational. ELISE is gaining early experience of the performance and operation of large RF-driven negative hydrogen ion sources with plasma illumination of a source area of 1 × 0.9 m(2) and an extraction area of 0.1 m(2) using 640 apertures. First results in volume operation, i.e., without caesium seeding, are presented.

Modeling and Bayesian parameter estimation for shape memory alloy bending actuators

NASA Astrophysics Data System (ADS)

Crews, John H.; Smith, Ralph C.

2012-04-01

In this paper, we employ a homogenized energy model (HEM) for shape memory alloy (SMA) bending actuators. Additionally, we utilize a Bayesian method for quantifying parameter uncertainty. The system consists of a SMA wire attached to a flexible beam. As the actuator is heated, the beam bends, providing endoscopic motion. The model parameters are fit to experimental data using an ordinary least-squares approach. The uncertainty in the fit model parameters is then quantified using Markov Chain Monte Carlo (MCMC) methods. The MCMC algorithm provides bounds on the parameters, which will ultimately be used in robust control algorithms. One purpose of the paper is to test the feasibility of the Random Walk Metropolis algorithm, the MCMC method used here.

Heat transfer modelling of pulsed laser-tissue interaction

NASA Astrophysics Data System (ADS)

Urzova, J.; Jelinek, M.

2018-03-01

Due to their attributes, the application of medical lasers is on the rise in numerous medical fields. From a biomedical point of view, the most interesting applications are the thermal interactions and the photoablative interactions, which effectively remove tissue without excessive heat damage to the remaining tissue. The objective of this work is to create a theoretical model for heat transfer in the tissue following its interaction with the laser beam to predict heat transfer during medical laser surgery procedures. The dimensions of the ablated crater (shape and ablation depth) were determined by computed tomography imaging. COMSOL Multiphysics software was used for temperature modelling. The parameters of tissue and blood, such as density, specific heat capacity, thermal conductivity and diffusivity, were calculated from the chemical ratio. The parameters of laser-tissue interaction, such as absorption and reflection coefficients, were experimentally determined. The parameters of the laser beam were power density, repetition frequency, pulse length and spot dimensions. Heat spreading after laser interaction with tissue was captured using a Fluke thermal camera. The model was verified for adipose tissue, skeletal muscle tissue and heart muscle tissue.

Proceedings of the Air Force Geophysics Laboratory Workshop on Natural Charging of Large Space Structures in Near Earth Polar Orbit: 14-15 September 1982

DTIC Science & Technology

1983-01-25

and its sheatlwith respect to the ambient plasma. *The FPEG was designed and built by Dr. John Raitt of Utah State University apd Dr. Peter Banks of...S. J., and Kellog , P. J. (1978) Heating of the ambient ionosphere by an artificially injected electron beam, J. Geophys. Res. 83:16. 286 The above...Cartwright, D.G., Monsoon, S.J., and Kellog , P.J. (1978) Heating of the ambient ionosphere by an artificially injected electron beam, J. Geophys. Res. 83

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cifuentes, A.; Departamento de Física Aplicada I, Escuela Técnica Superior de Ingeniería, Universidad del País Vasco UPV/EHU, Alameda Urquijo s/n, 48013 Bilbao; Alvarado, S.

Here, we present a novel application of the shadowgraph technique for obtaining the thermal diffusivity of an opaque solid sample, inspired by the orthogonal skimming photothermal beam deflection technique. This new variant utilizes the shadow projected by the sample when put against a collimated light source. The sample is then heated periodically by another light beam, giving rise to thermal waves, which propagate across it and through its surroundings. Changes in the refractive index of the surrounding media due to the heating distort the shadow. This phenomenon is recorded and lock-in amplified in order to determine the sample's thermal diffusivity.

Innovative real-time and non-destructive method of beam profile measurement under large beam current irradiation for BNCT

NASA Astrophysics Data System (ADS)

Takada, M.; Kamada, S.; Suda, M.; Fujii, R.; Nakamura, M.; Hoshi, M.; Sato, H.; Endo, S.; Hamano, T.; Arai, S.; Higashimata, A.

2012-10-01

We developed a real-time and non-destructive method of beam profile measurement on a target under large beam current irradiation, and without any complex radiation detectors or electrical circuits. We measured the beam profiles on a target by observing the target temperature using an infrared-radiation thermometer camera. The target temperatures were increased and decreased quickly by starting and stopping the beam irradiation within 1 s in response speed. Our method could trace beam movements rapidly. The beam size and position were calibrated by measuring O-ring heat on the target. Our method has the potential to measure beam profiles at beam current over 1 mA for proton and deuteron with the energy around 3 MeV and allows accelerator operators to adjust the beam location during beam irradiation experiments without decreasing the beam current.

Sensitivity of fenestration solar gain to source spectrum and angle of incidence

DOE Office of Scientific and Technical Information (OSTI.GOV)

McCluney, W.R.

1996-12-31

The solar heat gain coefficient (SHGC) is the fraction of solar radiant flux incident on a fenestration system entering a building as heat gain. In general it depends on both the angle of incidence and the spectral distribution of the incident solar radiation. In attempts to improve energy performance and user acceptance of high-performance glazing systems, manufacturers are producing glazing systems with increasing spectral selectivity. This poses potential difficulties for calculations of solar heat gain through windows based upon the use of a single solar spectral weighting function. The sensitivity of modern high-performance glazing systems to both the angle ofmore » incidence and the shape of the incident solar spectrum is examined using a glazing performance simulation program. It is found that as the spectral selectivity of the glazing system increases, the SHGC can vary as the incident spectral distribution varies. The variations can be as great as 50% when using several different representative direct-beam spectra. These include spectra having low and high air masses and a standard spectrum having an air mass of 1.5. The variations can be even greater if clear blue diffuse skylight is considered. It is recommended that the current broad-band shading coefficient method of calculating solar gain be replaced by one that is spectral based.« less

A scanned focused ultrasound device for hyperthermia: numerical simulation and prototype implementation

NASA Astrophysics Data System (ADS)

Meaney, Paul M.; Raynolds, Timothy; Geimer, Shireen D.; Potwin, Lincoln; Paulsen, Keith D.

2004-07-01

We are developing a scanned focused ultrasound system for hyperthermia treatment of breast cancer. Focused ultrasound has significant potential as a therapy delivery device because it can focus sufficient heating energy below the skin surface with minimal damage to intervening tissue. However, as a practical therapy system, the focal zone is generally quite small and requires either electronic (in the case of a phased array system) or mechanical steering (for a fixed bowl transducer) to cover a therapeutically useful area. We have devised a simple automated steering system consisting of a focused bowl transducer supported by three vertically movable rods which are connected to computer controlled linear actuators. This scheme is particularly attractive for breast cancer hyperthermia where the support rods can be fed through the base of a liquid coupling tank to treat tumors within the breast while coupled to our noninvasive microwave thermal imaging system. A MATLAB routine has been developed for controlling the rod motion such that the beam focal point scans a horizontal spiral and the subsequent heating zone is cylindrical. In coordination with this effort, a 3D finite element thermal model has been developed to evaluate the temperature distributions from the scanned focused heating. In this way, scanning protocols can be optimized to deliver the most uniform temperature rise to the desired location.

NASA-sponsored containerless processing experiments

NASA Technical Reports Server (NTRS)

Hofmeister, William H.

1990-01-01

An outline is presented of containerless processing and facilities at Intersonics which is sponsored by NASA. There are electromagnetic, acoustic, and aerodynamic levitation facilities. There are also laser beam and arc lamp heating systems along with state of the art noncontact temperature and optical property measurement facilities. Nonintrusive diagnostic techniques with Laser Induced Fluorescence and mass spectrometer are also available. Controlled atmosphere processing, gas quenching, and proven microgravity processing technology is part of the Intersonics capabilities.

Use of beam deflection to control an electron beam wire deposition process

NASA Technical Reports Server (NTRS)

Taminger, Karen M. (Inventor); Hofmeister, William H. (Inventor); Hafley, Robert A. (Inventor)

2013-01-01

A method for controlling an electron beam process wherein a wire is melted and deposited on a substrate as a molten pool comprises generating the electron beam with a complex raster pattern, and directing the beam onto an outer surface of the wire to thereby control a location of the wire with respect to the molten pool. Directing the beam selectively heats the outer surface of the wire and maintains the position of the wire with respect to the molten pool. An apparatus for controlling an electron beam process includes a beam gun adapted for generating the electron beam, and a controller adapted for providing the electron beam with a complex raster pattern and for directing the electron beam onto an outer surface of the wire to control a location of the wire with respect to the molten pool.

Method and apparatus for measuring properties of particle beams using thermo-resistive material properties

DOEpatents

Degtiarenko, Pavel V.; Dotson, Danny Wayne

2007-10-09

A beam position detector for measuring the properties of a charged particle beam, including the beam's position, size, shape, and intensity. One or more absorbers are constructed of thermo-resistive material and positioned to intercept and absorb a portion of the incoming beam power, thereby causing local heating of each absorber. The local temperature increase distribution across the absorber, or the distribution between different absorbers, will depend on the intensity, size, and position of the beam. The absorbers are constructed of a material having a strong dependence of electrical resistivity on temperature. The beam position detector has no moving parts in the vicinity of the beam and is especially suited to beam areas having high ionizing radiation dose rates or poor beam quality, including beams dispersed in the transverse direction and in their time radio frequency structure.

Thermal Fatigue Study of W/cu Joint

NASA Astrophysics Data System (ADS)

Zhang, Fu; Wu, Jihong; Xu, Zengyu; Xu, Ying

2003-06-01

HHFC mock-ups with a structure of W/Cu/SS were developed by hot isostatic pressing (HIP). The performance of the W/Cu joint under high heat loads was tested using an electron beam. The size of specimens for heat load tests was 25×25 mm and the size of beam spot on the specimen surface was 22 mm in diameter. During heat load test, the specimens were water-cooled. Thermal fatigue test were conducted at power density of 8.7 MW/m2 with pulse duration of 20 seconds and interval of 20 seconds. After 1000 cycles of tests, no cracks and failure were found in the W/Cu joint. The thermal performance was also investigated in the range of 1 ~ 9 MW/m2.

Comparative Study of button BPM Trapped Mode Heating

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cameron,P.; Singh, O.

2009-05-04

The combination of short bunches and high currents found in modern light sources and colliders can result in the deposition of tens of watts of power in BPM buttons. The resulting thermal distortion is potentially problematic for maintaining high precision beam position stability, and in the extreme case can result in mechanical damage. We present a simple algorithm that uses the input parameters of beam current, bunch length, button diameter, beampipe aperture, and fill pattern to calculate a relative figure-of-merit for button heating. Data for many of the world's light sources and colliders is compiled in a table. Using themore » algorithm, the table is sorted in order of the relative magnitude of button heating.« less