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Sample records for helium 8

  1. 48 CFR 52.208-8 - Required Sources for Helium and Helium Usage Data.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Helium and Helium Usage Data. 52.208-8 Section 52.208-8 Federal Acquisition Regulations System FEDERAL... Provisions and Clauses 52.208-8 Required Sources for Helium and Helium Usage Data. As prescribed in 8.505, insert the following clause: Required Sources for Helium and Helium Usage Data (APR 2002) (a)...

  2. 48 CFR 52.208-8 - Required Sources for Helium and Helium Usage Data.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Helium and Helium Usage Data. 52.208-8 Section 52.208-8 Federal Acquisition Regulations System FEDERAL... Provisions and Clauses 52.208-8 Required Sources for Helium and Helium Usage Data. As prescribed in 8.505, insert the following clause: Required Sources for Helium and Helium Usage Data (APR 2014) (a)...

  3. 48 CFR 52.208-8 - Required Sources for Helium and Helium Usage Data.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Helium and Helium Usage Data. 52.208-8 Section 52.208-8 Federal Acquisition Regulations System FEDERAL... Provisions and Clauses 52.208-8 Required Sources for Helium and Helium Usage Data. As prescribed in 8.505, insert the following clause: Required Sources for Helium and Helium Usage Data (APR 2002) (a)...

  4. 48 CFR 52.208-8 - Required Sources for Helium and Helium Usage Data.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Helium and Helium Usage Data. 52.208-8 Section 52.208-8 Federal Acquisition Regulations System FEDERAL... Provisions and Clauses 52.208-8 Required Sources for Helium and Helium Usage Data. As prescribed in 8.505, insert the following clause: Required Sources for Helium and Helium Usage Data (APR 2002) (a)...

  5. 48 CFR 52.208-8 - Required Sources for Helium and Helium Usage Data.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Helium and Helium Usage Data. 52.208-8 Section 52.208-8 Federal Acquisition Regulations System FEDERAL... Provisions and Clauses 52.208-8 Required Sources for Helium and Helium Usage Data. As prescribed in 8.505, insert the following clause: Required Sources for Helium and Helium Usage Data (APR 2002) (a)...

  6. 8. ORIGINAL HELIUM COMPRESSOR, CIRCA 1957, BY HASKELL ENGINEERING, GLENDALE, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    8. ORIGINAL HELIUM COMPRESSOR, CIRCA 1957, BY HASKELL ENGINEERING, GLENDALE, CALIFORNIA. Looking north. - Edwards Air Force Base, Air Force Rocket Propulsion Laboratory, Helium Compression Plant, Test Area 1-115, intersection of Altair & Saturn Boulevards, Boron, Kern County, CA

  7. Thermophysical properties of Helium-4 from 0. 8 to 1500 K with pressures to 2000 MPa

    SciTech Connect

    Arp, V.D.; Mccarty, R.D.

    1989-11-01

    Tabular summary data of the thermophysical properties of fluid helium are given for temperatures from 0.8 to 1500 K, with pressures to 2000 MPa between 75 and 300 K, or to 100 MPa outside of this temperature band. Properties include density, specific heats, enthalpy, entropy, internal energy, sound velocity, expansivity, compressibility, thermal conductivity, and viscosity. The data are calculated from a computer program which is available from the National Institute of Standards and Technology. The computer program is based on carefully fitted state equations for both normal and superfluid helium.

  8. Properties of V-(8-9)Cr-(5-6)Ti alloys irradiated in the dynamic helium charging experiment

    SciTech Connect

    Chung, H.M.; Nowicki, L.; Smith, D.L.

    1996-10-01

    In the Dynamic Helium Charging Experiment (DHCE), helium was produced uniformly in vanadium alloy specimens by the decay of tritium during irradiation to 18-31 dpa at 425-600{degrees}C in lithium-filled capsules in the Fast Flux Test Facility. This report presents results of postirradiation tests of tensile properties and density change in V-8Cr-6Ti and V-9Cr-5Ti. Compared to tensile properties of the alloys irradiated in the non-DHCE (helium generation negligible), the effect of helium on tensile strength and ductility of V-8Cr-6Ti and V-9Cr-5Ti was insignificant after irradiation and testing at 420, 500, and 600{degrees}C. Both alloys retained a total elongation of >11 % at these temperatures. Density change was <0.48% for both alloys.

  9. Thermophysical properties of Helium-4 from 0.8 to 1500 K with pressures to 2000 MPa

    NASA Technical Reports Server (NTRS)

    Arp, Vincent D.; Mccarty, Robert D.

    1989-01-01

    Tabular summary data of the thermophysical properties of fluid helium are given for temperatures from 0.8 to 1500 K, with pressures to 2000 MPa between 75 and 300 K, or to 100 MPa outside of this temperature band. Properties include density, specific heats, enthalpy, entropy, internal energy, sound velocity, expansivity, compressibility, thermal conductivity, and viscosity. The data are calculated from a computer program which is available from the National Institute of Standards and Technology. The computer program is based on carefully fitted state equations for both normal and superfluid helium.

  10. Studies on the effects of helium on the microstructural evolution of V-3.8Cr-3.9Ti

    SciTech Connect

    Doraiswamy, N.; Kestel, B.; Alexander, D.E.

    1997-04-01

    The favorable physical and mechanical properties of V-3.8Cr-3.9Ti (wt.%), when subjected to neutron irradiation, has lead to considerable attention being focused on it for use in fusion reactor structural applications. However, there is limited data on the effects of helium on physical and mechanical properties of this alloy. Understanding these effects are important since helium will be generated by direct {alpha}-injection or transmutation reactions in the fusion environment, typically at a rate of {approx}5 appm He/dpa. Helium has been shown to cause substantial embrittlement, even at room temperature in vanadium and its alloys. Recent simulations of the fusion environment using the Dynamic Helium Charging Experiments (DHCE) have also indicated that the mechanical properties of vanadium alloys are altered by the presence of helium in post irradiation tests performed at room temperature. While the strengths were lower, room temperature ductilities of the DHCE specimens were higher than those of non-DHCE specimens. These changes have been attributed to the formation of different types of hardening centers in these alloys due to He trapping. Independent thermal desorption experiments suggest that these hardening centers may be associated with helium-vacancy-X (where X = O, N, and C) complexes. These complexes are stable below 290{degrees}C and persist at room temperature. However, there has been no direct microstructural evidence correlating the complexes with irradiation effects. An examination of the irradiation induced microstructure in samples preimplanted with He to different levels would enable such a correlation.

  11. Design, Project Execution, and Commissioning of the 1.8 K Superfluid Helium Refrigeration System for SRF Cryomodule Testing

    DOE PAGESBeta

    Treite, P.; Nuesslein, U.; Jia, Yi; Klebaner, A.; Theilacker, J.

    2015-07-15

    The Fermilab Cryomodule Test Facility (CMTF) provides a test bed to measure the performance of superconducting radiofrequency (SRF) cryomodules (CM). These SRF components form the basic building blocks of future high intensity accelerators such as the International Linear Collider (ILC) and a Muon Collider. Linde Kryotechnik AG and Linde Cryogenics have designed, constructed and commissioned the superfluid helium refrigerator needed to support SRF component testing at the CMTF Facility. The hybrid refrigerator is designed to operate in a variety of modes and under a wide range of boundary conditions down to 1.8 Kelvin set by CM design. Special features ofmore » the refrigerator include the use of warm and cold compression and high efficiency turbo expanders.This paper gives an overview on the wide range of the challenging cooling requirements, the design, fabrication and the commissioning of the installed cryogenic system.« less

  12. Design, Project Execution, and Commissioning of the 1.8 K Superfluid Helium Refrigeration System for SRF Cryomodule Testing

    SciTech Connect

    Treite, P.; Nuesslein, U.; Jia, Yi; Klebaner, A.; Theilacker, J.

    2015-07-15

    The Fermilab Cryomodule Test Facility (CMTF) provides a test bed to measure the performance of superconducting radiofrequency (SRF) cryomodules (CM). These SRF components form the basic building blocks of future high intensity accelerators such as the International Linear Collider (ILC) and a Muon Collider. Linde Kryotechnik AG and Linde Cryogenics have designed, constructed and commissioned the superfluid helium refrigerator needed to support SRF component testing at the CMTF Facility. The hybrid refrigerator is designed to operate in a variety of modes and under a wide range of boundary conditions down to 1.8 Kelvin set by CM design. Special features of the refrigerator include the use of warm and cold compression and high efficiency turbo expanders.This paper gives an overview on the wide range of the challenging cooling requirements, the design, fabrication and the commissioning of the installed cryogenic system.

  13. Design, Project Execution, and Commissioning of the 1.8 K Superfluid Helium Refrigeration System for SRF Cryomodule Testing

    NASA Astrophysics Data System (ADS)

    Treite, P.; Nuesslein, U.; Jia, Yi; Klebaner, A.; Theilacker, J.

    The Fermilab Cryomodule Test Facility (CMTF) provides a test bed to measure the performance of superconducting radiofrequency (SRF) cryomodules (CM). These SRF components form the basic building blocks of future high intensity accelerators such as the International Linear Collider (ILC) and a Muon Collider. Linde Kryotechnik AG and Linde Cryogenics have designed, constructed and commissioned the superfluid helium refrigerator needed to support SRF component testing at the CMTF Facility. The hybrid refrigerator is designed to operate in a variety of modes and under a wide range of boundary conditions down to 1.8 Kelvin set by CM design. Special features of the refrigerator include the use of warm and cold compression and high efficiency turbo expanders.This paper gives an overview on the wide range of the challenging cooling requirements, the design, fabrication and the commissioning of the installed cryogenic system.

  14. A simple 2 W continuous-wave laser system for trapping ultracold metastable helium atoms at the 319.8 nm magic wavelength

    NASA Astrophysics Data System (ADS)

    Rengelink, R. J.; Notermans, R. P. M. J. W.; Vassen, W.

    2016-05-01

    High-precision spectroscopy on the 2 ^3 S → 2 ^1 S transition is possible in ultracold optically trapped helium, but the accuracy is limited by the ac-Stark shift induced by the optical dipole trap. To overcome this problem, we have built a trapping laser system at the predicted magic wavelength of 319.8 nm. Our system is based on frequency conversion using commercially available components and produces over 2 W of power at this wavelength. With this system, we show trapping of ultracold atoms, both thermal (~0.2 μk) and in a Bose-Einstein condensate, with a trap lifetime of several seconds, mainly limited by off-resonant scattering.

  15. Helium cryopumping for fusion applications

    SciTech Connect

    Sedgley, D.W.; Batzer, T.H.; Call, W.R.

    1988-05-01

    Large quantities of helium and hydrogen isotopes will be exhausted continuously from fusion power reactors. This paper summarizes two development programs undertaken to address vacuum pumping for this application: (i) A continuous duty cryopump for pumping helium and/or hydrogen species using charcoal sorbent and (ii) a cryopump configuration with an alternative shielding arrangement using charcoal sorbent or argon spray. A test program evaluated automatic pumping of helium, helium pumping by charcoal cryosorption and with argon spray, and cryosorption of helium/hydrogen mixtures. The continuous duty cryopump pumped helium continuously and conveniently. Helium pumping speed was 7.7 l/s/cm/sup 2/ of charcoal, compared to 5.8 l/s/cm/sup 2/ for the alternative pump. Helium speed using argon spray was 18% of that obtained by charcoal cryosorption in the same (W-panel) pump. During continuous duty cryopump mixture tests with helium and hydrogen copumped on charcoal, gas was released sporadically. Testing was insufficient to explain this unacceptable event.

  16. 21 CFR 868.1640 - Helium gas analyzer.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Helium gas analyzer. 868.1640 Section 868.1640...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Diagnostic Devices § 868.1640 Helium gas analyzer. (a) Identification. A helium gas analyzer is a device intended to measure the concentration of helium in a...

  17. 21 CFR 868.1640 - Helium gas analyzer.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Helium gas analyzer. 868.1640 Section 868.1640...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Diagnostic Devices § 868.1640 Helium gas analyzer. (a) Identification. A helium gas analyzer is a device intended to measure the concentration of helium in a...

  18. 21 CFR 868.1640 - Helium gas analyzer.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Helium gas analyzer. 868.1640 Section 868.1640...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Diagnostic Devices § 868.1640 Helium gas analyzer. (a) Identification. A helium gas analyzer is a device intended to measure the concentration of helium in a...

  19. 21 CFR 868.1640 - Helium gas analyzer.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Helium gas analyzer. 868.1640 Section 868.1640...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Diagnostic Devices § 868.1640 Helium gas analyzer. (a) Identification. A helium gas analyzer is a device intended to measure the concentration of helium in a...

  20. 21 CFR 868.1640 - Helium gas analyzer.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Helium gas analyzer. 868.1640 Section 868.1640...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Diagnostic Devices § 868.1640 Helium gas analyzer. (a) Identification. A helium gas analyzer is a device intended to measure the concentration of helium in a...

  1. Simultaneous Pickup Ion Observations of the Interstellar Helium Focusing Cone with STEREO PLASTIC in 2007/8

    NASA Astrophysics Data System (ADS)

    Kucharek, Harald

    The relative motion of the Sun through the Local Interstellar Cloud (LIC) with 26 km/s leads to a neutral interstellar wind through the heliosphere. Because of its high ionization potential, the He remains neutral well within 1 AU, where it forms a focusing cone in the downwind direction due to the Sun's gravity. This flow pattern has been intensely studied with many UV backscattering experiments, through pickup ions (AMPTE, Ulysses, SOHO, and ACE), and through atom imaging (Ulysses). Recently, a consistent set of the physical parameters of He in the LIC has been derived combining all three methods. However, it became obvious that the strong 3-D spatial and temporal variability of the ionization processes is a main limitation to the accuracy. It is particularly puzzling that the pickup ion fluxes vary substantially on temporal scales from hours to many days, thus leading to apparent changes in the appearance of the cone, even after significant averaging. Thus far the causes of the pickup ion flux variations have been elusive. Using the PLASTIC instrument on STEREO A and B, we present the first simultaneous pickup ion observations of the He focusing cone from two different locations with identical instrumentation. We will compare these observations also with ACE SWICS observations, at a location upstream of Earth between the two STEREO locations. This configuration allows a separation of spatial and temporal variations in the pickup ion fluxes and spectra and their influence on the shape of the cone. Of particular interest is how the observed variations relate to the large scale pattern of solar wind structures, since compressions and rarefactions can substantially alter pickup ion distributions and fluxes. We will present the pickup ion spectra for the 2007/8 He focusing cone crossing from both spacecraft, compare the cone shape with current hot models of the interstellar flow, and relate observed deviations from a smooth cone to large scale solar wind patterns.

  2. Helium in the topside Venus ionosphere

    NASA Technical Reports Server (NTRS)

    Herman, J. R.

    1972-01-01

    The quantity of helium in the Venus atmosphere is estimated from an examination of the measured ionization profiles. The amount of helium necessary to give agreement between the computed and experimental results is approximately 4 x 10 to the 8th power/cucm at 140 km. When an eddy diffusion coefficient of 1,000,000 sq cm/see is used, the atmospheric helium mixing ratio is found to be 0.0006; a value nearly ten times that for earth.

  3. Test of a cryogenic helium pump

    SciTech Connect

    Lue, J.W.; Miller, J.R.; Walstrom, P.L.; Herz, W.

    1981-01-01

    The design of a cryogenic helium pump for circulating liquid helium in a magnet and the design of a test loop for measuring the pump performance in terms of mass flow vs pump head at various pump speeds are described. A commercial cryogenic helium pump was tested successfully. Despite flaws in the demountable connections, the piston pump itself has performed satisfactorily. A helium pump of this type is suitable for the use of flowing supercritical helium through Internally Cooled Superconductor (ICS) magnets. It has pumped supercritical helium up to 7.5 atm with a pump head up to 2.8 atm. The maximum mass flow rate obtained was about 16 g/s. Performance of the pump was degraded at lower pumping speeds. (LCL)

  4. Test of a cryogenic helium pump

    NASA Astrophysics Data System (ADS)

    Lue, J. W.; Miller, J. R.; Walstrom, P. L.; Herz, W.

    1981-02-01

    The design of a cryogenic helium pump for circulating liquid helium in a magnet and the design of a test loop for measuring the pump performance in terms of mass flow vs pump head at various pump speeds are described. A commercial cryogenic helium pump was tested successfully. Despite flaws in the demountable connections, the piston pump itself has performed satisfactorily. A helium pump of this type is suitable for the use of flowing supercritical helium through internally cooled superconductor magnets. It has pumped supercritical helium up to 7.5 atm with a pump head up to 2.8 atm. The maximum mass flow rate obtained was about 16 g/s. Performance of the pump was degraded at lower pumping speeds.

  5. Use of double and triple-ion irradiation to study the influence of high levels of helium and hydrogen on void swelling of 8-12% Cr ferritic-martensitic steels

    NASA Astrophysics Data System (ADS)

    Kupriiyanova, Y. E.; Bryk, V. V.; Borodin, O. V.; Kalchenko, A. S.; Voyevodin, V. N.; Tolstolutskaya, G. D.; Garner, F. A.

    2016-01-01

    In accelerator-driven spallation (ADS) devices, some of the structural materials will be exposed to intense fluxes of very high energy protons and neutrons, producing not only displacement damage, but very high levels of helium and hydrogen. Unlike fission flux-spectra where most helium and hydrogen are generated by transmutation in nickel and only secondarily in iron or chromium, gas production in ADS flux-spectra are rather insensitive to alloy composition, such that Fe-Cr base ferritic alloys also generate very large gas levels. While ferritic alloys are known to swell less than austenitic alloys in fission spectra, there is a concern that high gas levels in fusion and especially ADS facilities may strongly accelerate void swelling in ferritic alloys. In this study of void swelling in response to helium and hydrogen generation, irradiation was conducted on three ferritic-martensitic steels using the Electrostatic Accelerator with External Injector (ESUVI) facility that can easily produce any combination of helium to dpa and/or hydrogen to dpa ratios. Irradiation was conducted under single, dual and triple beam modes using 1.8 MeV Cr+3, 40 keV He+, and 20 keV H+. In the first part of this study we investigated the response of dual-phase EP-450 to variations in He/dpa and H/dpa ratio, focusing first on dual ion studies and then triple ion studies, showing that there is a diminishing influence on swelling with increasing total gas content. In the second part we investigated the relative response of three alloys spanning a range of starting microstructure and composition. In addition to observing various synergisms between He and H, the most important conclusion was that the tempered martensite phase, known to lag behind the ferrite phase in swelling in the absence of gases, loses much of its resistance to void nucleation when irradiated at large gas/dpa levels.

  6. Helium superfluidity. Shapes and vorticities of superfluid helium nanodroplets.

    PubMed

    Gomez, Luis F; Ferguson, Ken R; Cryan, James P; Bacellar, Camila; Tanyag, Rico Mayro P; Jones, Curtis; Schorb, Sebastian; Anielski, Denis; Belkacem, Ali; Bernando, Charles; Boll, Rebecca; Bozek, John; Carron, Sebastian; Chen, Gang; Delmas, Tjark; Englert, Lars; Epp, Sascha W; Erk, Benjamin; Foucar, Lutz; Hartmann, Robert; Hexemer, Alexander; Huth, Martin; Kwok, Justin; Leone, Stephen R; Ma, Jonathan H S; Maia, Filipe R N C; Malmerberg, Erik; Marchesini, Stefano; Neumark, Daniel M; Poon, Billy; Prell, James; Rolles, Daniel; Rudek, Benedikt; Rudenko, Artem; Seifrid, Martin; Siefermann, Katrin R; Sturm, Felix P; Swiggers, Michele; Ullrich, Joachim; Weise, Fabian; Zwart, Petrus; Bostedt, Christoph; Gessner, Oliver; Vilesov, Andrey F

    2014-08-22

    Helium nanodroplets are considered ideal model systems to explore quantum hydrodynamics in self-contained, isolated superfluids. However, exploring the dynamic properties of individual droplets is experimentally challenging. In this work, we used single-shot femtosecond x-ray coherent diffractive imaging to investigate the rotation of single, isolated superfluid helium-4 droplets containing ~10(8) to 10(11) atoms. The formation of quantum vortex lattices inside the droplets is confirmed by observing characteristic Bragg patterns from xenon clusters trapped in the vortex cores. The vortex densities are up to five orders of magnitude larger than those observed in bulk liquid helium. The droplets exhibit large centrifugal deformations but retain axially symmetric shapes at angular velocities well beyond the stability range of viscous classical droplets. PMID:25146284

  7. The effects of convective overshooting on naked helium stars

    NASA Astrophysics Data System (ADS)

    Yan, Jing-Zhi; Zhu, Chun-Hua; Wang, Zhao-Jun; Lü, Guo-Liang

    2016-09-01

    Using stellar evolutionary models, we investigate the effects of convective overshooting on naked helium stars. We find that a larger value of overshooting parameter δov results in a larger convective core, which prolongs the lifetimes of naked helium stars on the helium main sequence and leads to higher effective temperatures and luminosities. For naked helium stars with masses lower than about 0.8 M⊙, they hardly become giant stars as a result of a weak burning shell. However, naked helium stars with masses between about 0.8 M⊙ and 1.1 M⊙ can evolve into giant branch phases, and finally become carbon oxygen white dwarfs.

  8. 48 CFR 8.501 - Definitions.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... REQUIRED SOURCES OF SUPPLIES AND SERVICES Acquisition of Helium 8.501 Definitions. As used in this subpart... Office, Helium Operations, 801 South Fillmore Street, Suite 500, Amarillo, TX 79101-3545. Federal helium supplier means a private helium vendor that has an in-kind crude helium sales contract with the Bureau...

  9. 48 CFR 8.501 - Definitions.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... REQUIRED SOURCES OF SUPPLIES AND SERVICES Acquisition of Helium 8.501 Definitions. As used in this subpart... Office, Helium Operations, 801 South Fillmore Street, Suite 500, Amarillo, TX 79101-3545. Federal helium supplier means a private helium vendor that has an in-kind crude helium sales contract with the Bureau...

  10. 48 CFR 8.501 - Definitions.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... REQUIRED SOURCES OF SUPPLIES AND SERVICES Acquisition of Helium 8.501 Definitions. As used in this subpart... Office, Helium Operations, 801 South Fillmore Street, Suite 500, Amarillo, TX 79101-3545. Federal helium supplier means a private helium vendor that has an in-kind crude helium sales contract with the Bureau...

  11. 48 CFR 8.501 - Definitions.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... REQUIRED SOURCES OF SUPPLIES AND SERVICES Acquisition of Helium 8.501 Definitions. As used in this subpart... Office, Helium Operations, 801 South Fillmore Street, Suite 500, Amarillo, TX 79101-3545. Federal helium supplier means a private helium vendor that has an in-kind crude helium sales contract with the Bureau...

  12. 48 CFR 8.501 - Definitions.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... REQUIRED SOURCES OF SUPPLIES AND SERVICES Acquisition of Helium 8.501 Definitions. As used in this subpart... Office, Helium Operations, 801 South Fillmore Street, Suite 500, Amarillo, TX 79101-3545. Federal helium supplier means a private helium vendor that has an in-kind crude helium sales contract with the Bureau...

  13. 48 CFR 8.502 - Policy.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... REQUIRED SOURCES OF SUPPLIES AND SERVICES Acquisition of Helium 8.502 Policy. Agencies and their contractors and subcontractors must purchase major helium requirements from Federal helium suppliers, to...

  14. 48 CFR 8.502 - Policy.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... REQUIRED SOURCES OF SUPPLIES AND SERVICES Acquisition of Helium 8.502 Policy. Agencies and their contractors and subcontractors must purchase major helium requirements from Federal helium suppliers, to...

  15. 48 CFR 8.502 - Policy.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... REQUIRED SOURCES OF SUPPLIES AND SERVICES Acquisition of Helium 8.502 Policy. Agencies and their contractors and subcontractors must purchase major helium requirements from Federal helium suppliers, to...

  16. 48 CFR 8.502 - Policy.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... REQUIRED SOURCES OF SUPPLIES AND SERVICES Acquisition of Helium 8.502 Policy. Agencies and their contractors and subcontractors must purchase major helium requirements from Federal helium suppliers, to...

  17. 48 CFR 8.502 - Policy.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... REQUIRED SOURCES OF SUPPLIES AND SERVICES Acquisition of Helium 8.502 Policy. Agencies and their contractors and subcontractors must purchase major helium requirements from Federal helium suppliers, to...

  18. Helium-Recycling Plant

    NASA Technical Reports Server (NTRS)

    Cook, Joseph

    1996-01-01

    Proposed system recovers and stores helium gas for reuse. Maintains helium at 99.99-percent purity, preventing water vapor from atmosphere or lubricating oil from pumps from contaminating gas. System takes in gas at nearly constant low back pressure near atmospheric pressure; introduces little or no back pressure into source of helium. Concept also extended to recycling of other gases.

  19. A helium regenerative compressor

    SciTech Connect

    Swift, W.L.; Nutt, W.E.; Sixsmith, H.

    1994-12-31

    This paper discusses the design and performance of a regenerative compressor that was developed primarily for use in cryogenic helium systems. The objectives for the development were to achieve acceptable efficiency in the machine using conventional motor and bearing technology while reducing the complexity of the system required to control contamination from the lubricants. A single stage compressor was built and tested. The compressor incorporates aerodynamically shaped blades on a 218 mm (8.6 inches) diameter impeller to achieve high efficiency. A gas-buffered non-contact shaft seal is used to oppose the diffusion of lubricant from the motor bearings into the cryogenic circuit. Since it is a rotating machine, the flow is continuous and steady, and the machine is very quiet. During performance testing with helium, the single stage machine has demonstrated a pressure ratio of 1.5 at a flow rate of 12 g/s with measured isothermal efficiencies in excess of 30%. This performance compares favorably with efficiencies generally achieved in oil flooded screw compressors.

  20. Helium diffusion in the sun

    NASA Technical Reports Server (NTRS)

    Bahcall, J. N.; Pinsonneault, M. H.

    1992-01-01

    We calculate improved standard solar models using the new Livermore (OPAL) opacity tables, an accurate (exportable) nuclear energy generation routine which takes account of recent measurements and analyses, and the recent Anders-Grevesse determination of heavy element abundances. We also evaluate directly the effect of the diffusion of helium with respect to hydrogen on the calculated neutrino fluxes, on the primordial solar helium abundance, and on the depth of the convective zone. Helium diffusion increases the predicted event rates by about 0.8 SNU, or 11 percent of the total rate, in the chlorine solar neutrino experiment, by about 3.5 SNU, or 3 percent, in the gallium solar neutrino experiments, and by about 12 percent in the Kamiokande and SNO solar neutrino experiments. The best standard solar model including helium diffusion and the most accurate nuclear parameters, element abundances, and radiative opacity predicts a value of 8.0 SNU +/- 3.0 SNU for the C1-37 experiment and 132 +21/-17 SNU for the Ga - 71 experiment, where the uncertainties include 3 sigma errors for all measured input parameters.

  1. Study of the single cluster response of a helium-isobutane drift chamber prototype using 8 keV X-rays

    NASA Astrophysics Data System (ADS)

    Cavoto, G.; Dabagov, S.; Hampai, D.; Piredda, G.; Renga, F.; Ripiccini, E.; Voena, C.; Zullo, A.

    2015-03-01

    The identification of single clusters in the electronic signals produced by ionizing particles within a drift chamber is expected to significantly improve the performances of this kind of detectors in terms of particle identification capabilities and space resolution. In order to develop refined cluster recognition algorithms, it is essential to measure the response of the chamber and its electronics to single ionization clusters. This can be done by irradiating the chamber with X-rays. We report here on the studies performed on a drift chamber prototype for the MEG-II experiment at the X-ray facility of the INFN Frascati's National Laboratories ``XLab Frascati''. The prototype is operated with a helium-isobutane mixture and instrumented with high bandwidth custom pre-amplifiers. The results of this study have been used to develop an innovative method for cluster recognition, based on the Wiener filter technique, which has been tested on data collected at the Frascati's Beam Test Facility. As a side measurement, we also performed a study of the gas gain in a configuration which is similar to that of the MEG-II experiment.

  2. 48 CFR 8.505 - Contract clause.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... REQUIRED SOURCES OF SUPPLIES AND SERVICES Acquisition of Helium 8.505 Contract clause. Insert the clause at 52.208-8, Required Sources for Helium and Helium Usage Data, in solicitations and contracts if it is anticipated that performance of the contract involves a major helium requirement....

  3. 48 CFR 8.505 - Contract clause.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... REQUIRED SOURCES OF SUPPLIES AND SERVICES Acquisition of Helium 8.505 Contract clause. Insert the clause at 52.208-8, Required Sources for Helium and Helium Usage Data, in solicitations and contracts if it is anticipated that performance of the contract involves a major helium requirement....

  4. 48 CFR 8.505 - Contract clause.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... REQUIRED SOURCES OF SUPPLIES AND SERVICES Acquisition of Helium 8.505 Contract clause. Insert the clause at 52.208-8, Required Sources for Helium and Helium Usage Data, in solicitations and contracts if it is anticipated that performance of the contract involves a major helium requirement....

  5. 48 CFR 8.505 - Contract clause.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... REQUIRED SOURCES OF SUPPLIES AND SERVICES Acquisition of Helium 8.505 Contract clause. Insert the clause at 52.208-8, Required Sources for Helium and Helium Usage Data, in solicitations and contracts if it is anticipated that performance of the contract involves a major helium requirement....

  6. 48 CFR 8.505 - Contract clause.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... REQUIRED SOURCES OF SUPPLIES AND SERVICES Acquisition of Helium 8.505 Contract clause. Insert the clause at 52.208-8, Required Sources for Helium and Helium Usage Data, in solicitations and contracts if it is anticipated that performance of the contract involves a major helium requirement....

  7. Superfluid Helium Heat Pipe

    NASA Astrophysics Data System (ADS)

    Gully, P.

    This paper reports on the development and the thermal tests of three superfluid helium heat pipes. Two of them are designed to provide a large transport capacity (4 mW at 1.7 K). They feature a copper braid located inside a 6 mm outer diameter stainless tube fitted with copper ends for mechanical anchoring. The other heat pipe has no copper braid and is designed to get much smaller heat transport capacity (0.5 mW) and to explore lower temperature (0.7 - 1 K). The copper braid and the tube wall is the support of the Rollin superfluid helium film in which the heat is transferred. The low filling pressure makes the technology very simple with the possibility to easily bend the tube. We present the design and discuss the thermal performance of the heat pipes tested in the 0.7 to 2.0 K temperature range. The long heat pipe (1.2 m with copper braid) and the short one (0.25 m with copper braid) have similar thermal performance in the range 0.7 - 2.0 K. At 1.7 K the long heat pipe, 120 g in weight, reaches a heat transfer capacity of 6.2 mW and a thermal conductance of 600 mW/K for 4 mW transferred power. Due to the pressure drop of the vapor flow and Kapitza thermal resistance, the conductance of the third heat pipe dramatically decreases when the temperature decreases. A 3.8 mW/K is obtained at 0.7 K for 0.5 mW transferred power.

  8. Thermal desorption behavior of helium in aged titanium tritide films

    NASA Astrophysics Data System (ADS)

    Cheng, G. J.; Shi, L. Q.; Zhou, X. S.; Liang, J. H.; Wang, W. D.; Long, X. G.; Yang, B. F.; Peng, S. M.

    2015-11-01

    The desorption behavior of helium in TiT(1.5∼1.8)-x3Hex film samples (x = 0.0022-0.22) was investigated by thermal desorption technique in vacuum condition in this paper. The thermal helium desorption spectrometry (THDS) of aging titanium tritide films prepared by electron beam evaporation revealed that, depending on the decayed 3He concentration in the samples, there are more than four states of helium existing in the films. The divided four zones in THDS based on helium states represent respectively: (1) the mobile single helium atoms with low activation energy in all aging samples resulted from the interstitial sites or dissociated from interstitial clusters, loops and dislocations, (2) helium bubbles inside the grain lattices, (3) helium bubbles in the grain boundaries and interconnected networks of dislocations in the helium concentration of 3Hegen/Ti > 0.0094, and (4) helium bubbles near or linked to the film surface by interconnected channel for later aging stage with 3Hegen/Ti > 0.18. The proportion of helium desorption in each zone was estimated, and dissociated energies of helium for different trapping states were given.

  9. Helium abundance enhancements in the solar wind

    NASA Technical Reports Server (NTRS)

    Borrini, G.; Gosling, J. T.; Bame, S. J.; Feldman, W. C.

    1982-01-01

    Evidence for a link between helium enhancements at 1 AU and transient coronal mass ejections is provided by the statistical analysis of 73 large helium abundance enhancement observations made by IMPs 6, 7 and 8 over 1972-1978. These events, in which helium abundance enhancement is greater than about 10%, are sporadic, sometimes clustered in time, occur approximately in phase with the solar cycle, and nearly 50% of them are associated with interplanetary shocks and/or geomagnetic activity sudden commencements. The plasma pattern associated with them is nevertheless independent of shock occurrence, and features high magnetic field strength, low alpha-proton velocity difference, and low proton temperature, suggesting that the enhancement is embedded in a closed, magnetically dominated structure that expands adiabatically. Evidence of an association between helium enhancement at 1 AU and type II and IV radio bursts in the corona is presented.

  10. ITER helium ash accumulation

    SciTech Connect

    Hogan, J.T.; Hillis, D.L.; Galambos, J.; Uckan, N.A. ); Dippel, K.H.; Finken, K.H. . Inst. fuer Plasmaphysik); Hulse, R.A.; Budny, R.V. . Plasma Physics Lab.)

    1990-01-01

    Many studies have shown the importance of the ratio {upsilon}{sub He}/{upsilon}{sub E} in determining the level of He ash accumulation in future reactor systems. Results of the first tokamak He removal experiments have been analysed, and a first estimate of the ratio {upsilon}{sub He}/{upsilon}{sub E} to be expected for future reactor systems has been made. The experiments were carried out for neutral beam heated plasmas in the TEXTOR tokamak, at KFA/Julich. Helium was injected both as a short puff and continuously, and subsequently extracted with the Advanced Limiter Test-II pump limiter. The rate at which the He density decays has been determined with absolutely calibrated charge exchange spectroscopy, and compared with theoretical models, using the Multiple Impurity Species Transport (MIST) code. An analysis of energy confinement has been made with PPPL TRANSP code, to distinguish beam from thermal confinement, especially for low density cases. The ALT-II pump limiter system is found to exhaust the He with maximum exhaust efficiency (8 pumps) of {approximately}8%. We find 1<{upsilon}{sub He}/{upsilon}{sub E}<3.3 for the database of cases analysed to date. Analysis with the ITER TETRA systems code shows that these values would be adequate to achieve the required He concentration with the present ITER divertor He extraction system.

  11. 48 CFR 8.504 - Procedures.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... REQUIRED SOURCES OF SUPPLIES AND SERVICES Acquisition of Helium 8.504 Procedures. The contracting officer... each fiscal quarter: (a) The name of any company that supplied a major helium requirement. (b) The amount of helium purchased. (c) The delivery date(s). (d) The location where the helium was used....

  12. 48 CFR 8.504 - Procedures.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... REQUIRED SOURCES OF SUPPLIES AND SERVICES Acquisition of Helium 8.504 Procedures. The contracting officer... each fiscal quarter: (a) The name of any company that supplied a major helium requirement. (b) The amount of helium purchased. (c) The delivery date(s). (d) The location where the helium was used....

  13. 48 CFR 8.504 - Procedures.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... REQUIRED SOURCES OF SUPPLIES AND SERVICES Acquisition of Helium 8.504 Procedures. The contracting officer... each fiscal quarter: (a) The name of any company that supplied a major helium requirement. (b) The amount of helium purchased. (c) The delivery date(s). (d) The location where the helium was used....

  14. 48 CFR 8.504 - Procedures.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... REQUIRED SOURCES OF SUPPLIES AND SERVICES Acquisition of Helium 8.504 Procedures. The contracting officer... each fiscal quarter: (a) The name of any company that supplied a major helium requirement. (b) The amount of helium purchased. (c) The delivery date(s). (d) The location where the helium was used....

  15. 48 CFR 8.504 - Procedures.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... REQUIRED SOURCES OF SUPPLIES AND SERVICES Acquisition of Helium 8.504 Procedures. The contracting officer... each fiscal quarter: (a) The name of any company that supplied a major helium requirement. (b) The amount of helium purchased. (c) The delivery date(s). (d) The location where the helium was used....

  16. The Descending Helium Balloon

    ERIC Educational Resources Information Center

    Helseth, Lars Egil

    2014-01-01

    I describe a simple and fascinating experiment wherein helium leaks out of a rubber balloon, thereby causing it to descend. An estimate of the volumetric leakage rate is made by measuring its rate of descent.

  17. Noncavitating Pump For Liquid Helium

    NASA Technical Reports Server (NTRS)

    Hasenbein, Robert; Izenson, Michael; Swift, Walter; Sixsmith, Herbert

    1996-01-01

    Immersion pump features high efficiency in cryogenic service. Simple and reliable centrifugal pump transfers liquid helium with mass-transfer efficiency of 99 percent. Liquid helium drawn into pump by helical inducer, which pressurizes helium slightly to prevent cavitation when liquid enters impeller. Impeller then pressurizes liquid. Purpose of pump to transfer liquid helium from supply to receiver vessel, or to provide liquid helium flow for testing and experimentation.

  18. Precision spectroscopy of Kaonic helium-3 and helium-4 3d-->2p X-rays

    NASA Astrophysics Data System (ADS)

    Ishiwatari, T.; Bazzi, M.; Bhang, H.; Beer, G.; Bombelli, L.; Bragadireanu, A. M.; Cargnelli, M.; Choi, S.; Corradi, G.; Curceanu, C.; d'Uffizi, A.; Enomoto, S.; Fiorini, C.; Frizzi, T.; Fujioka, H.; Fujiwara, Y.; Ghio, F.; Girolami, B.; Guaraldo, C.; Hashimoto, T.; Hayano, R. S.; Hiraiwa, T.; Iio, M.; Iliescu, M.; Ishimoto, S.; Itahashi, K.; Iwasaki, M.; Kienle, P.; Kou, H.; Levi Sandri, P.; Longoni, A.; Lucherini, V.; Marton, J.; Matsuda, Y.; Noumi, H.; Ohnishi, H.; Okada, S.; Outa, H.; Pietreanu, D.; Ponta, T.; Rizzo, A.; Romero Vidal, A.; Sakuma, F.; Sato, M.; Scordo, A.; Sekimoto, M.; Shi, H.; Sirghi, D. L.; Sirghi, F.; Suzuki, T.; Tanida, K.; Tatsuno, H.; Tokuda, M.; Tomono, D.; Toyoda, A.; Tsukada, K.; Tudorache, A.; Tudorache, V.; Vazquez Doce, O.; Widmann, E.; Wünschek, B.; Yamazaki, T.; Zmeskal, J.

    2010-08-01

    Recently, the shift of the kaonic helium-4 2p state was precisely determined by the E570 and SIDDHARTA experiments. Prior to the experiment by E570, the average of three earlier experimental results showed -43±8 eV, while most of the theoretical calculations give ˜0 eV. This five-sigma discrepancy between theory and experiment was known as the "kaonic helium puzzle". A recent theoretical model showed a possible resonance-like shift of maximum 10 eV for a certain value of a deep antikaon-nucleon interaction potential, which is different in helium 3 and helium 4. The E570 experiment determined the shift of the kaonic helium-4 2p state as +2±2 (stat)±2 (sys) eV in 2007. The SIDDHARTA experiment determined the shift as 0±6(stat)±2(sys) eV in 2009. The results of these experiments resolved the long-standing puzzle. A new experiment of the kaonic helium-3 X-ray measurement is being prepared by the J-PARC E17 collaborators, and the kaonic helium-3 X-ray data taken very recently by the SIDDHARTA experiment are on the way to be analyzed. The results of the E570, E17 and SIDDHARTA experiments examine the strong interaction for light nuclei with different isospin, and test furthermore recent theoretical predictions.

  19. Single-electron-capture processes in collisions of He{sup 2+}, Li{sup q+} (q=1,2,3), C{sup 6+}, and O{sup 8+} ions with helium

    SciTech Connect

    Samanta, R.; Purkait, M.; Mandal, C. R.

    2011-03-15

    Cross sections for single-electron capture in collisions of He{sup 2+}, Li{sup q+} (q = 1,2,3), C{sup 6+}, and O{sup 8+} ions with helium atoms at incident energy ranging from 50 to 5000 keV/amu have been calculated in the framework of four-body boundary-corrected continuum intermediate state (BCCIS-4B) approximation in both prior and post forms. In this formalism, distortion in the final channel related to the Coulomb continuum states of the projectile ion and the active electron in the field of residual target ion are included. In all cases, total single-electron-capture cross sections have been calculated by summing over all contributions up to n = 3 shells and subshells, respectively. It has been observed that the contribution of the capture cross section into the excited states is significant for asymmetric collision (Z{sub P}>Z{sub T}) and is insignificant for symmetric collision. Numerical results for the total cross sections show good agreement with the available experimental findings, particularly in the post form. Post-prior discrepancy has been found to be within 30% except for Li{sup +} + He interactions below 150 keV/amu.

  20. Helium-refrigeration system

    SciTech Connect

    Specht, J.R.; Millar, B.; Sutherland, A.

    1995-08-01

    The design, procurement, and preliminary construction was completed for adding two more wet expansion engines to two helium refrigerators. These will be added in mid-year FY 1995. In addition a variable speed drive will be added to an existing helium compressor. This is part of an energy conservation upgrade project to reduce operating costs from the use of electricity and liquid nitrogen. This project involves the replacement of Joule-Thompson valves in the refrigerators with expansion engines resulting in system efficiency improvements of about 30% and improved system reliability.

  1. Is solid helium a supersolid?

    SciTech Connect

    Hallock, Robert

    2015-05-15

    Recent experiments suggest that helium-4 atoms can flow through an experimental cell filled with solid helium. But that incompletely understood flow is quite different from the reported superfluid-like motion that so excited physicists a decade ago.

  2. The Kaonic Helium Case

    NASA Astrophysics Data System (ADS)

    Curceanu (Petrascu), C.; Bragadireanu, A. M.; Curceanu (Petrascu), C.; Ghio, F.; Girolami, B.; Guaraldo, C.; Iliescu, M.; Levi Sandri, P.; Lucherini, V.; Sirghi, D. L.; Sirghi, F.; Cargnelli, M.; Fuhrmann, H.; Ishiwatari, T.; Kienle, P.; Marton, J.; Zmeskal, J.; Fiorini, C.; Longoni, A.; Frizzi, T.; Itahashi, K.; Iwasaki, M.; Koike, T.; Ponta, T.; Soltau, H.; Lechner, P.; Struder, L.

    2005-12-01

    The only three existent kaonic helium X-ray transition measurements at present are referring to the transitions to 2p level. These measurements are more than 30 years old and the obtained results, affected by big errors, are much larger than those predicted by optical models. It is thought that the optical model is inadequate, due to the presence of the ∧(1405) resonance, not properly taken into account. Because the nucleons in the helium nucleus are tightly bound, the effective energy of the K-p interaction (1432 MeV at threshold) is in helium much closer to the energy of the resonance than in other nuclei. It is then planned to measure the kaonic helium X-ray transitions to the 2p level in the framework of the SIDDHARTA (SIlicon Drift Detector for Hadronic Atom Research by Timing Application) experiment, at the DAΦNE collider of Frascati National Laboratories, and to confirm or not the discrepancy reported by the previous experiments with a much smaller error.

  3. On Helium Anions in Helium Droplets: Interpreting Recent Experiments

    NASA Astrophysics Data System (ADS)

    Mauracher, Andreas; Huber, Stefan E.

    2014-10-01

    Helium droplets provide an ideal environment to study elementary processes in atomic systems at very low temperatures. Here, we discuss properties of charged and neutral, atomic and molecular helium species formed in helium droplets upon electron impact. By studying their interaction with atomic ground state helium we find that He, He2 and excited (metastable) He*- are well bound within the helium droplet. In comparison, He* , He2* and He2* are found to be squeezed out due to energetic reasons. We also present the formation pathways of atomic and molecular helium anions in helium droplets. Transition barriers in the energetic lowest He*- - He interaction potentials prevent molecule formation at the extremely low temperatures in helium droplets. In contrast, some excited states allow a barrier-free formation of molecular helium (anions). With these theoretical results at hand we can interpret recent experiments in which the resonant formation of atomic and molecular helium anions was observed. Furthermore, we give an outlook on the implications of the presence of these anionic species in doped helium droplets with regard to charge transfer reactions. Austrian Fund Agency (FWF, I 978-N20, DK+ project Computational Interdisciplinary Modelling W1227-N16)/Austrian Ministry of Science (BMWF, Konjunkturpaket II, UniInfrastrukturprogramm of the Focal Point Scientific Computing).

  4. Helium in the Martian atmosphere - Thermal loss considerations

    NASA Technical Reports Server (NTRS)

    Levine, J. S.; Keating, G. M.; Prior, E. J.

    1974-01-01

    Helium concentrations in the Martian atmosphere are estimated assuming that the helium production on Mars (comparable to its production on earth) via the radioactive decay of uranium and thorium is in steady state equilibrium with its thermal escape. Although nonthermal losses would tend to reduce the estimated concentrations, these concentrations are not necessarily an upper limit since higher production rates and/or a possibly lower effective exospheric temperature over the solar activity cycle could increase them to even higher values. The computed helium concentration at the Martian exobase (200 km) is 8 million atoms/cu cm. Through the lower exosphere, the computed helium concentrations are 30-200 times greater than the Mariner-measured atomic hydrogen concentrations. It follows that helium may be the predominant constituent in the Martian lower exosphere and may well control the orbital lifetime of Mars-orbiting spacecraft.

  5. Helium anion formation inside helium droplets

    NASA Astrophysics Data System (ADS)

    Jabbour Al Maalouf, Elias; Reitshammer, Julia; Ribar, Anita; Scheier, Paul; Denifl, Stephan

    2016-07-01

    The formation of He∗- is examined with improved electron energy resolution of about 100 meV utilizing a hemispherical electron monochromator. The work presented provides a precise determination of the three previously determined resonance peak positions that significantly contribute to the formation of He∗- inside helium nanodroplets in the energy range from 20 eV to 29.5 eV. In addition, a new feature is identified located at 27.69 ± 0.18 eV that we assign to the presence of O2 as a dopant inside the droplet. With increasing droplet size a small blue shift of the resonance positions is observed. Also for the relatively low electron currents used in the present study (i.e., 15-70 nA) a quadratic dependence of the He∗- ion yield on the electron current is observed.

  6. 48 CFR 8.503 - Exception.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... REQUIRED SOURCES OF SUPPLIES AND SERVICES Acquisition of Helium 8.503 Exception. The requirements of this subpart do not apply to contracts or subcontracts in which the helium was acquired by the contractor...

  7. 48 CFR 8.503 - Exception.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... REQUIRED SOURCES OF SUPPLIES AND SERVICES Acquisition of Helium 8.503 Exception. The requirements of this subpart do not apply to contracts or subcontracts in which the helium was acquired by the contractor...

  8. 48 CFR 8.503 - Exception.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... REQUIRED SOURCES OF SUPPLIES AND SERVICES Acquisition of Helium 8.503 Exception. The requirements of this subpart do not apply to contracts or subcontracts in which the helium was acquired by the contractor...

  9. 48 CFR 8.503 - Exception.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... REQUIRED SOURCES OF SUPPLIES AND SERVICES Acquisition of Helium 8.503 Exception. The requirements of this subpart do not apply to contracts or subcontracts in which the helium was acquired by the contractor...

  10. 48 CFR 8.503 - Exception.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... REQUIRED SOURCES OF SUPPLIES AND SERVICES Acquisition of Helium 8.503 Exception. The requirements of this subpart do not apply to contracts or subcontracts in which the helium was acquired by the contractor...

  11. Feasibility of lunar Helium-3 mining

    NASA Astrophysics Data System (ADS)

    Kleinschneider, Andreas; Van Overstraeten, Dmitry; Van der Reijnst, Roy; Van Hoorn, Niels; Lamers, Marvin; Hubert, Laurent; Dijk, Bert; Blangé, Joey; Hogeveen, Joel; De Boer, Lennaert; Noomen, Ron

    -3 fusion were calculated using a predicted minimum energy price in 2040 of 30.4 Euro/MWh. Annual costs are between 427.7 to 1,347.9 billion Euro, with annual expected profit ranging from -724.0 to 260.0 billion Euro. Due to the large scale of the mission, it has also been evaluated for providing 0.1% and 1% of the global energy demand in 2040. For 1%, the annual costs are 45.6 to 140.3 billion Euro and the expected annual profits are -78.0 to 23.1 billion Euro. For 0.1%, the annual costs are 7.7 to 20.5 billion Euro. The annual expected profits are -14.3 to -0.8 billion Euro. Feasibility has been addressed in three aspects. Technically, the mission is extremely challenging and complex. However, most required technologies exist or could be developed within a reasonable time span. From a political and legal perspective, the current international treaties hardly provide any framework for a lunar mining operation. Financially, the mission only produces a net profit in the best case, and only for medium- to large-scale operations, which require a very large initial investment. To make lunar Helium-3 usage possible, further research should concentrate on the mining operation and costs of fusion plants, as their impact by far outranks all other mission elements. Different transportation concepts may be investigated nevertheless. Many - not only technical - challenges concerning Helium-3 mining are still to be addressed. Although only a starting point for further investigations, this study shows that, despite popular claims, lunar Helium-3 is unsuitable to provide a significant percentage of the global energy demand in 2040.

  12. Applications of Groundwater Helium

    USGS Publications Warehouse

    Kulongoski, Justin T.; Hilton, David R.

    2011-01-01

    Helium abundance and isotope variations have widespread application in groundwater-related studies. This stems from the inert nature of this noble gas and the fact that its two isotopes ? helium-3 and helium-4 ? have distinct origins and vary widely in different terrestrial reservoirs. These attributes allow He concentrations and 3He/4He isotope ratios to be used to recognize and quantify the influence of a number of potential contributors to the total He budget of a groundwater sample. These are atmospheric components, such as air-equilibrated and air-entrained He, as well as terrigenic components, including in situ (aquifer) He, deep crustal and/or mantle He and tritiogenic 3He. Each of these components can be exploited to reveal information on a number of topics, from groundwater chronology, through degassing of the Earth?s crust to the role of faults in the transfer of mantle-derived volatiles to the surface. In this review, we present a guide to how groundwater He is collected from aquifer systems and quantitatively measured in the laboratory. We then illustrate the approach of resolving the measured He characteristics into its component structures using assumptions of endmember compositions. This is followed by a discussion of the application of groundwater He to the types of topics mentioned above using case studies from aquifers in California and Australia. Finally, we present possible future research directions involving dissolved He in groundwater.

  13. Helium anion formation inside helium droplets

    NASA Astrophysics Data System (ADS)

    Maalouf, Elias Jabbour Al; Reitshammer, Julia; Ribar, Anita; Scheier, Paul; Denifl, Stephan

    2016-07-01

    The formation of He∗- is examined with improved electron energy resolution of about 100 meV utilizing a hemispherical electron monochromator. The work presented provides a precise determination of the three previously determined resonance peak positions that significantly contribute to the formation of He∗- inside helium nanodroplets in the energy range from 20 eV to 29.5 eV. In addition, a new feature is identified located at 27.69 ± 0.18 eV that we assign to the presence of O2 as a dopant inside the droplet. With increasing droplet size a small blue shift of the resonance positions is observed. Also for the relatively low electron currents used in the present study (i.e., 15-70 nA) a quadratic dependence of the He∗- ion yield on the electron current is observed. Contribution to the Topical Issue "Advances in Positron and Electron Scattering", edited by Paulo Limao-Vieira, Gustavo Garcia, E. Krishnakumar, James Sullivan, Hajime Tanuma and Zoran Petrovic.

  14. Energetic helium particles trapped in the magnetosphere

    NASA Technical Reports Server (NTRS)

    Chen, Jiasheng; Guzik, T. Gregory; Sang, Yeming; Wefel, John P.; Cooper, John F.

    1994-01-01

    High energy (approximately 40-100 MeV/nucleon) geomagnetically trapped helium nuclei have been measured, for the first time, by the ONR-604 instrument during the 1990/1991 Combined Release and Radiation Effects Satellite (CRRES) mission. The helium events observed at L less than 2.3 have a pitch angle distribution peaking perpendicular to the local magnetic field and are contained in peaks located at L = 1.2 and 1.9. The events in each peak can be characterized by power law energy spectra with indices of 10.0 +/- 0.7 for L = 1.9-2.3 and 6.8 +/- 1.0 for L = 1.15-1.3, before the large storm of 24 March 1991. CRRES was active during solar maximum when the anomalous component is excluded from the inner heliosphere, making it unlikely that the observed events derived from the anomalous component. The trapped helium counting rates decrease gradually with time indicating that these high energy ions were not injected by flares during the 1990/91 mission. Flare injection prior to mid-1990 may account for the highest energy particles, while solar wind injection during magnetic storms and subsequent acceleration could account for the helium at lower energies.

  15. Helium-induced reactions in astrophysics

    SciTech Connect

    Hale, G.M.

    1997-11-01

    Helium-induced reactions play a crucial role in stellar nucleosynthesis. Carbon and oxygen are produced mainly during the helium-burning phase by the chain of reactions {sup 8}Be({alpha}, {gamma} + e{sup +}e{sup {minus}}){sup 12}C({alpha}, {gamma}){sup 16}O. The first step, often called triple-{alpha} capture, was proposed by Hoyle to bypass the mass stability gap at {sup 8}Be. The second step gives rise to the largest uncertainty in most of the calculated stellar abundances. Later {alpha}-captures on {sup 13}C are believed to be a major source of s-process neutrons. The status of each of these important reactions is reviewed here.

  16. Helium jet dispersion to atmosphere

    NASA Astrophysics Data System (ADS)

    Khan, Hasna J.

    On the event of loss of vacuum guard of superinsulated helium dewar, high rate of heat transfer into the tank occurs. The rapid boiling of liquid helium causes the burst disk to rupture at four atmospheres and consequently the helium passes to the atmosphere through vent lines. The gaseous helium forms a vertical buoyant jet as it exits the vent line into a stagnant environment. Characterization of the gaseous jet is achieved by detailed analysis of the axial and radial dependence of the flow parameters.

  17. Influence of flowing helium gas on plasma plume formation in atmospheric pressure plasma

    SciTech Connect

    Yambe, Kiyoyuki; Konda, Kohmei; Ogura, Kazuo

    2015-05-15

    We have studied atmospheric pressure plasma generated using a quartz tube, helium gas, and a foil electrode by applying RF high voltage. The atmospheric pressure plasma in the form of a bullet is released as a plume into the atmosphere. The helium gas flowing out of quartz tube mixes with air, and the flow channel is composed of the regions of flowing helium gas and air. The plasma plume length is equivalent to the reachable distance of flowing helium gas. Although the amount of helium gas on the flow channel increases by increasing the inner diameter of quartz tube at the same gas flow velocity, the plasma plume length peaks at around 8 m/s of gas flow velocity, which is the result that a flow of helium gas is balanced with the amount of gas. The plasma plume is formed at the boundary region where the flow of helium gas is kept to the wall of the air.

  18. Calculation of hydrogen and helium concentrations for CSNS target

    NASA Astrophysics Data System (ADS)

    Pan, Dong-Dong; Liang, Tai-Ran; Yin, Wen; Yao, Ze-En

    2016-03-01

    The China Spallation Neutron Source (CSNS) is driven by protons whose energies are about 1.6 GeV. At such high energies, the spallation neutrons lead to the formation of large amounts of helium, hydrogen and new heavier species in the form of transmutation products. These hydrogen, helium and transmutation products have a critical effect on the mechanical properties on the one hand and exacerbate the displacement radiation damage on the other hand. In this paper, the background hydrogen/helium concentrations and the maximum hydrogen/helium concentrations near cracks in a tungsten target for CSNS have been calculated at temperatures of 100°C and 300°C by applying a theoretical model. For the CSNS tungsten target plate, we find the maximum hydrogen concentration near the tips of cracks ranges from 3.0 × 10-2-2 × 10-1, which exceeds the hydrogen background concentration by 1.2-1.8 times; the maximum helium concentration near the tips of cracks ranges from 3.0 × 10-4 -1.2 × 10-3, which exceeds the helium background concentration by 2-4 times; the maximum hydrogen/helium concentration increases with the increase of the transfer length across the surfaces of the target and it decreases with the increase of temperature. Supported by National Science Foundation of China (51371195, 11174358)

  19. Regimes of Helium Burning

    SciTech Connect

    Timmes, F. X.; Niemeyer, J. C.

    2000-07-10

    The burning regimes encountered by laminar deflagrations and Zeldovich von Neumann Doering [ZND] detonations propagating through helium-rich compositions in the presence of buoyancy-driven turbulence are analyzed. Particular attention is given to models of X-ray bursts that start with a thermonuclear runaway on the surface of a neutron star and to the thin-shell helium instability of intermediate-mass stars. In the X-ray burst case, turbulent deflagrations propagating in the lateral or radial direction encounter a transition from the distributed regime to the flamelet regime at a density of {approx}108 g cm-3. In the radial direction, the purely laminar deflagration width is larger than the pressure scale height for densities smaller than {approx}106 g cm-3. Self-sustained laminar deflagrations traveling in the radial direction cannot exist below this density. Similarly, the planar ZND detonation width becomes larger than the pressure scale height at {approx}107 g cm-3, suggesting that steady state, self-sustained detonations cannot come into existence in the radial direction. In the thin helium shell case, turbulent deflagrations traveling in the lateral or radial direction encounter the distributed regime at densities below {approx}107 g cm-3 and the flamelet regime at larger densities. In the radial direction, the purely laminar deflagration width is larger than the pressure scale height for densities smaller than {approx}104 g cm-3, indicating that steady state laminar deflagrations cannot form below this density. The planar ZND detonation width becomes larger than the pressure scale height at {approx}5x10{sup 4} g cm-3, suggesting that steady state, self-sustained detonations cannot come into existence in the radial direction. (c) 2000 The American Astronomical Society.

  20. Tensile behavior of helium charged VTiCrSi type alloys

    NASA Astrophysics Data System (ADS)

    Satou, M.; Koide, H.; Hasegawa, A.; Abe, K.; Kayano, H.; Matsui, H.

    1996-10-01

    Helium effect on the mechanical properties of the alloy V5Ti5Cr1SiAl,Y (nominal) was studied, adopting various helium charging methods and helium-to-dpa ratio. The first method was helium ion implantation using a cyclotron accelerator at Tohoku University, where helium and displacement levels were 50 appm and 0.02 dpa, respectively. The second, helium was charged by tritium trick technique and following neutron irradiation in FFTF/MOTA-2A, associated with about 80 appm He and 43 dpa. The third was dynamic helium charging experiment (DHCE) conducted in FFTF/MOTA-2B, where helium was generated within specimens during neutron irradiation by tritium decay, and the helium-to-dpa ratio was adjusted to simulate the fusion reactor condition, that is, 177 appm He and 24 dpa. The effect of helium on tensile properties of the VTiCrSiAl,Y alloy depended on the helium charging methods. The uniform elongation of the alloy was 3.2% and total elongation was 8.3% at DHCE condition, which was the most fusion relevant condition of the methods. It is important that tensile properties of the present alloy could be acceptable for fusion reactor component materials.

  1. Helium dilution refrigeration system

    DOEpatents

    Roach, P.R.; Gray, K.E.

    1988-09-13

    A helium dilution refrigeration system operable over a limited time period, and recyclable for a next period of operation is disclosed. The refrigeration system is compact with a self-contained pumping system and heaters for operation of the system. A mixing chamber contains [sup 3]He and [sup 4]He liquids which are precooled by a coupled container containing [sup 3]He liquid, enabling the phase separation of a [sup 3]He rich liquid phase from a dilute [sup 3]He-[sup 4]He liquid phase which leads to the final stage of a dilution cooling process for obtaining low temperatures. The mixing chamber and a still are coupled by a fluid line and are maintained at substantially the same level with the still cross sectional area being smaller than that of the mixing chamber. This configuration provides maximum cooling power and efficiency by the cooling period ending when the [sup 3]He liquid is depleted from the mixing chamber with the mixing chamber nearly empty of liquid helium, thus avoiding unnecessary and inefficient cooling of a large amount of the dilute [sup 3]He-[sup 4]He liquid phase. 2 figs.

  2. Helium dilution refrigeration system

    DOEpatents

    Roach, Patrick R.; Gray, Kenneth E.

    1988-01-01

    A helium dilution refrigeration system operable over a limited time period, and recyclable for a next period of operation. The refrigeration system is compact with a self-contained pumping system and heaters for operation of the system. A mixing chamber contains .sup.3 He and .sup.4 He liquids which are precooled by a coupled container containing .sup.3 He liquid, enabling the phase separation of a .sup.3 He rich liquid phase from a dilute .sup.3 He-.sup.4 He liquid phase which leads to the final stage of a dilution cooling process for obtaining low temperatures. The mixing chamber and a still are coupled by a fluid line and are maintained at substantially the same level with the still cross sectional area being smaller than that of the mixing chamber. This configuration provides maximum cooling power and efficiency by the cooling period ending when the .sup.3 He liquid is depleted from the mixing chamber with the mixing chamber nearly empty of liquid helium, thus avoiding unnecessary and inefficient cooling of a large amount of the dilute .sup.3 He-.sup.4 He liquid phase.

  3. THERMAL OSCILLATIONS IN LIQUID HELIUM TARGETS.

    SciTech Connect

    WANG,L.; JIA,L.X.

    2001-07-16

    A liquid helium target for the high-energy physics was built and installed in the proton beam line at the Alternate Gradient Synchrotron of Brookhaven National Laboratory in 2001. The target flask has a liquid volume of 8.25 liters and is made of thin Mylar film. A G-M/J-T cryocooler of five-watts at 4.2K was used to produce liquid helium and refrigerate the target. A thermosyphon circuit for the target was connected to the J-T circuit by a liquid/gas separator. Because of the large heat load to the target and its long transfer lines, thermal oscillations were observed during the system tests. To eliminate the oscillation, a series of tests and analyses were carried out. This paper describes the phenomena and provides the understanding of the thermal oscillations in the target system.

  4. Precision spectroscopy of Helium

    SciTech Connect

    Cancio, P.; Giusfredi, G.; Mazzotti, D.; De Natale, P.; De Mauro, C.; Krachmalnicoff, V.; Inguscio, M.

    2005-05-05

    Accurate Quantum-Electrodynamics (QED) tests of the simplest bound three body atomic system are performed by precise laser spectroscopic measurements in atomic Helium. In this paper, we present a review of measurements between triplet states at 1083 nm (23S-23P) and at 389 nm (23S-33P). In 4He, such data have been used to measure the fine structure of the triplet P levels and, then, to determine the fine structure constant when compared with equally accurate theoretical calculations. Moreover, the absolute frequencies of the optical transitions have been used for Lamb-shift determinations of the levels involved with unprecedented accuracy. Finally, determination of the He isotopes nuclear structure and, in particular, a measurement of the nuclear charge radius, are performed by using hyperfine structure and isotope-shift measurements.

  5. Resource Letter SH-1: Superfluid Helium.

    ERIC Educational Resources Information Center

    Hallock, Robert B.

    1982-01-01

    Provides an annotated list of books, textbooks, and films on superfluid helium. Also lists research reports/reviews arranged by category, including among others, early history, microscopic understanding, ions in helium, helium in rotation, vortices and quantization, helium films and constricted geometrics, persistence flow, and superfluid helium…

  6. Tables of thermodynamic properties of helium magnet coolant. Revision A

    SciTech Connect

    McAshan, M.

    1992-07-01

    The most complete treatment of the thermodynamic properties of helium at the present time is the monograph by McCarty: ``Thermodynamic Properties of Helium 4 from 2 to 1500 K at Pressures to 10{sup 8} Pa``, Robert D. McCarty, Journal of Physical and Chemical Reference Data, Vol. 2, page 923--1040 (1973). In this work the complete range of data on helium is examined and the P-V-T surface is described by an equation of state consisting of three functions P(r,T) covering different regions together with rules for making the transition from one region to another. From this thermodynamic compilation together with correlations of the transport properties of helium was published the well-known NBS Technical Note: ``Thermophysical Properties of Helium 4 from 2 to 1500 K with pressures to 1000 Atmospheres``, Robert D. McCarty, US Department of Commerce, National Bureau of Standards Technical Note 631 (1972). This is the standard reference for helium cryogenics. The NBS 631 tables cover a wide range of temperature and pressure, and as a consequence, the number of points tabulated in the region of the single phase coolant for the SSC magnets are relatively few. The present work sets out to cover the range of interest in more detail in a way that is consistent with NBS 631. This new table is essentially identical to the older one and can be used as an auxiliary to it.

  7. Tables of thermodynamic properties of helium magnet coolant

    SciTech Connect

    McAshan, M.

    1992-07-01

    The most complete treatment of the thermodynamic properties of helium at the present time is the monograph by McCarty: Thermodynamic Properties of Helium 4 from 2 to 1500 K at Pressures to 10{sup 8} Pa'', Robert D. McCarty, Journal of Physical and Chemical Reference Data, Vol. 2, page 923--1040 (1973). In this work the complete range of data on helium is examined and the P-V-T surface is described by an equation of state consisting of three functions P(r,T) covering different regions together with rules for making the transition from one region to another. From this thermodynamic compilation together with correlations of the transport properties of helium was published the well-known NBS Technical Note: Thermophysical Properties of Helium 4 from 2 to 1500 K with pressures to 1000 Atmospheres'', Robert D. McCarty, US Department of Commerce, National Bureau of Standards Technical Note 631 (1972). This is the standard reference for helium cryogenics. The NBS 631 tables cover a wide range of temperature and pressure, and as a consequence, the number of points tabulated in the region of the single phase coolant for the SSC magnets are relatively few. The present work sets out to cover the range of interest in more detail in a way that is consistent with NBS 631. This new table is essentially identical to the older one and can be used as an auxiliary to it.

  8. Tables of thermodynamic properties of helium magnet coolant, revision A

    NASA Astrophysics Data System (ADS)

    McAshan, M.

    1992-07-01

    The most complete treatment of the thermodynamic properties of helium at the present time is the monograph by McCarty: 'Thermodynamic Properties of Helium 4 from 2 to 1500 K at Pressures to 10(exp 8) Pa', Robert D. McCarty, Journal of Physical and Chemical Reference Data, Vol. 2, page 923-1040 (1973). In this work the complete range of data on helium is examined and the P-V-T surface is described by an equation of state consisting of three functions P(r,T) covering different regions together with rules for making the transition from one region to another. From this thermodynamic compilation together with correlations of the transport properties of helium was published the well-known NBS Technical Note: 'Thermophysical Properties of Helium 4 from 2 to 1500 K with pressures to 1000 Atmospheres', Robert D. McCarty, US Department of Commerce, National Bureau of Standards Technical Note 631 (1972). This is the standard reference for helium cryogenics. The NBS 631 tables cover a wide range of temperature and pressure, and as a consequence, the number of points tabulated in the region of the single phase coolant for the SSC magnets are relatively few. The present work sets out to cover the range of interest in more detail in a way that is consistent with NBS 631. This new table is essentially identical to the older one and can be used as an auxiliary to it.

  9. Test program, helium II orbital resupply coupling

    NASA Technical Reports Server (NTRS)

    Hyatt, William S.

    1991-01-01

    The full scope of this program was to have included development tests, design and production of custom test equipment and acceptance and qualification testing of prototype and protoflight coupling hardware. This program was performed by Ball Aerospace Systems Division, Boulder, Colorado until its premature termination in May 1991. Development tests were performed on cryogenic face seals and flow control devices at superfluid helium (He II) conditions. Special equipment was developed to allow quantified leak detection at large leak rates up to 8.4 x 10(exp -4) SCCS. Two major fixtures were developed and characterized: The Cryogenic Test Fixture (CTF) and the Thermal Mismatch Fixture (Glovebox). The CTF allows the coupling hardware to be filled with liquid nitrogen (LN2), liquid helium (LHe) or sub-cooled liquid helium when hardware flow control valves are either open or closed. Heat leak measurements, internal and external helium leakage measurements, cryogenic proof pressure tests and external load applications are performed in this fixture. Special reusable MLI closures were developed to provide repeatable installations in the CTF. The Thermal Mismatch Fixture allows all design configurations of coupling hardware to be engaged and disengaged while measuring applied forces and torques. Any two hardware components may be individually thermally preconditioned within the range of 117 deg K to 350 deg K prior to engage/disengage cycling. This verifies dimensional compatibility and operation when thermally mismatched. A clean, dry GN2 atmosphere is maintained in the fixture at all times. The first shipset of hardware was received, inspected and cycled at room temperature just prior to program termination.

  10. Helium and Neon in Comets

    NASA Technical Reports Server (NTRS)

    Jewitt, David

    1996-01-01

    Two comets were observed with EUVE in late 1994. Both comet Mueller and comet Borrelly are short-period comets having well established orbital elements and accurate ephemerides. Spectra of 40 ksec were taken of each. No evidence for emission lines from either Helium or Neon was detected. We calculated limits on the production rates of these atoms (relative to solar) assuming a standard isotropic outflow model, with a gas streaming speed of 1 km/s. The 3-sigma (99.7% confidence) limits (1/100,000 for He, 0.8 for Ne) are based on a conservative estimate of the noise in the EUVE spectra. They are also weakly dependent on the precise pointing and tracking of the EUVE field of view relative to the comet during the integrations. These limits are consistent with ice formation temperatures T greater than or equal to 30 K, as judged from the gas trapping experiments of Bar-Nun. For comparison, the solar abundances of these elements are He/O = 110, Ne/O = 1/16. Neither limit was as constraining as we had initially hoped, mainly because comets Mueller and Borrelly were intrinsically less active than anticipated.

  11. Perspectives on Lunar Helium-3

    NASA Astrophysics Data System (ADS)

    Schmitt, Harrison H.

    1999-01-01

    Global demand for energy will likely increase by a factor of six or eight by the mid-point of the 21st Century due to a combination of population increase, new energy intensive technologies, and aspirations for improved standards of living in the less-developed world (1). Lunar helium-3 (3He), with a resource base in the Tranquillitatis titanium-rich lunar maria (2,3) of at least 10,000 tonnes (4), represents one potential energy source to meet this rapidly escalating demand. The energy equivalent value of 3He delivered to operating fusion power plants on Earth would be about 3 billion per tonne relative to today's coal which supplies most of the approximately 90 billion domestic electrical power market (5). These numbers illustrate the magnitude of the business opportunity. The results from the Lunar Prospector neutron spectrometer (6) suggests that 3He also may be concentrated at the lunar poles along with solar wind hydrogen (7). Mining, extraction, processing, and transportation of helium to Earth requires new innovations in engineering but no known new engineering concepts (1). By-products of lunar 3He extraction, largely hydrogen, oxygen, and water, have large potential markets in space and ultimately will add to the economic attractiveness of this business opportunity (5). Inertial electrostatic confinement (IEC) fusion technology appears to be the most attractive and least capital intensive approach to terrestrial fusion power plants (8). Heavy lift launch costs comprise the largest cost uncertainty facing initial business planning, however, many factors, particularly long term production contracts, promise to lower these costs into the range of 1-2000 per kilogram versus about 70,000 per kilogram fully burdened for the Apollo Saturn V rocket (1). A private enterprise approach to developing lunar 3He and terrestrial IEC fusion power would be the most expeditious means of realizing this unique opportunity (9). In spite of the large, long-term potential

  12. Low temperature uses of helium

    NASA Technical Reports Server (NTRS)

    Brown, G. V.

    1970-01-01

    Helium is used for purging and pressurizing cryogenic rocket propellants, welding, atmosphere control, leak detection, and refrigeration. It provides the lowest possible liquid-bath temperature and produces superconductivity in certain materials. Its superfluid effects are used in superconducting magnets.

  13. Swelling and structure of vanadium-base alloys irradiated in the dynamic helium charging experiment

    SciTech Connect

    Chung, H.M.; Loomis, B.A.; Smith, D.L.

    1994-08-01

    Combined effects of dynamically charged helium and neutron damage on density change, void distribution, and microstructural evolution of V-4Cr-4Ti alloy have been determined after irradiation to 18--31 dpa at 425--600 C in the Dynamic Helium Charging Experiment (DHCE), and the results were compared with those from a non-DHCE in which helium generation and negligible. For specimens irradiated to {approx}18-31 dpa at 500--600 with a helium generation rate of 0.4--4.2 appm He/dpa, only a few helium bubbles were observed at the interface of grain matrices and some of the Ti(O,N,C) precipitates, and no microvoids or helium bubbles were observed either in grain matrices or near grain boundaries. Under these conditions, dynamically produced helium atoms seem to be trapped in the grain matrix without significant bubble nucleation or growth, and in accordance with this, density changes from DHCE and non-DHCE (negligible helium generation) were similar for comparable fluence and irradiation temperature. Only for specimens irradiated to {approx}31 dpa at 425 C, when helium was generated at a rage of 0.4--0.8 appm helium/dpa, were diffuse helium bubbles observed in limited regions of grain matrices and near {approx}15% of the grain boundaries in densities significantly lower than those in the extensive coalescences of helium bubbles typical of other alloys irradiated in tritium-trick experiments. Density changes of specimens irradiated at 425 C in the DHCE were significantly higher than those from non-DHCE irradiation. Microstructural evolution in V-4Cr-4Ti was similar for DHCE and non-DHCE except for helium bubble number density and distribution. As in non-DHCE, the irradiation-induced precipitation of ultrafine Ti{sub 5}Si{sub 3} was observed for DHCE at >500 C but not at 425 C.

  14. Radiation source for helium magnetometers

    NASA Technical Reports Server (NTRS)

    Slocum, Robert E. (Inventor)

    1991-01-01

    A radiation source (12) for optical magnetometers (10) which use helium isotopes as the resonance element (30) includes an electronically pumped semiconductor laser (12) which produces a single narrow line of radiation which is frequency stabilized to the center frequency of the helium resonance line to be optically pumped. The frequency stabilization is accomplished using electronic feedback (34, 40, 42, 44) to control a current sources (20) thus eliminating the need for mechanical frequency tuning.

  15. COSMIC-RAY HELIUM HARDENING

    SciTech Connect

    Ohira, Yutaka; Ioka, Kunihito

    2011-03-01

    Recent observations by the CREAM and ATIC-2 experiments suggest that (1) the spectrum of cosmic-ray (CR) helium is harder than that of CR protons below the knee energy, 10{sup 15}eV, and (2) all CR spectra become hard at {approx}>10{sup 11}eV nucleon{sup -1}. We propose a new idea, that higher energy CRs are generated in a more helium-rich region, to explain the hardening without introducing different sources for CR helium. The helium-to-proton ratio at {approx}100 TeV exceeds the Big Bang abundance Y = 0.25 by several times, and the different spectrum is not reproduced within the diffusive shock acceleration theory. We argue that CRs are produced in a chemically enriched region, such as a superbubble, and the outward-decreasing abundance naturally leads to the hard spectrum of CR helium if CRs escape from the supernova remnant shock in an energy-dependent way. We provide a simple analytical spectrum that also fits well the hardening due to the decreasing Mach number in the hot superbubble with {approx}10{sup 6} K. Our model predicts hard and concave spectra for heavier CR elements.

  16. One-dimensional electron system over liquid helium

    NASA Astrophysics Data System (ADS)

    Kovdrya, Yu. Z.; Nikolaenko, V. A.; Gladchenko, S. P.

    2000-07-01

    A system close to a one-dimensional (1D) electron system on superfluid helium is realized in the experiments. A profiled substrate with a small dielectric constant is used to create a set of parallel channels on the surface of liquid helium. The mobility of carriers was measured in this system in the temperature range 0.5-1.8 K. For clean substrates the electron mobility increases with decreasing temperature and reaches high values at low temperatures. The results of experiments are found to be in a good agreement with the existing theory.

  17. Carbon Shell or Core Ignitions in White Dwarfs Accreting from Helium Stars

    NASA Astrophysics Data System (ADS)

    Brooks, Jared; Bildsten, Lars; Schwab, Josiah; Paxton, Bill

    2016-04-01

    White dwarfs accreting from helium stars can stably burn at the accreted rate and avoid the challenge of mass loss associated with unstable helium burning that is a concern for many SNe Ia scenarios. We study binaries with helium stars of mass 1.25{M}ȯ ≤slant {M}{{He}}≤slant 1.8{M}ȯ , which have lost their hydrogen rich envelopes in an earlier common envelope event and now orbit with periods ({P}{{orb}}) of several hours with non-rotating 0.84 and 1.0{M}ȯ C/O WDs. The helium stars fill their Roche lobes after exhaustion of central helium and donate helium on their thermal timescales (∼ {10}5 years). As shown by others, these mass transfer rates coincide with the steady helium burning range for WDs, and grow the WD core up to near the Chandrasekhar mass ({M}{{Ch}}) and a core carbon ignition. We show here, however, that many of these scenarios lead to an ignition of hot carbon ashes near the outer edge of the WD and an inward going carbon flame that does not cause an explosive outcome. For {P}{{orb}}=3 hr, 1.0{M}ȯ C/O WDs with donor masses {M}{{He}}≳ 1.8{M}ȯ experience a shell carbon ignition, while {M}{{He}}≲ 1.3{M}ȯ will fall below the steady helium burning range and undergo helium flashes before reaching core C ignition. Those with 1.3{M}ȯ ≲ {M}{{He}}≲ 1.7{M}ȯ will experience a core C ignition. We also calculate the retention fraction of accreted helium when the accretion rate leads to recurrent weak helium flashes.

  18. Rogue mantle helium and neon.

    PubMed

    Albarède, Francis

    2008-02-15

    The canonical model of helium isotope geochemistry describes the lower mantle as undegassed, but this view conflicts with evidence of recycled material in the source of ocean island basalts. Because mantle helium is efficiently extracted by magmatic activity, it cannot remain in fertile mantle rocks for long periods of time. Here, I suggest that helium with high 3He/4He ratios, as well as neon rich in the solar component, diffused early in Earth's history from low-melting-point primordial material into residual refractory "reservoir" rocks, such as dunites. The difference in 3He/4He ratios of ocean-island and mid-ocean ridge basalts and the preservation of solar neon are ascribed to the reservoir rocks being stretched and tapped to different extents during melting. PMID:18202257

  19. Pulsed helium ionization detection system

    DOEpatents

    Ramsey, Roswitha S.; Todd, Richard A.

    1987-01-01

    A helium ionization detection system is provided which produces stable operation of a conventional helium ionization detector while providing improved sensitivity and linearity. Stability is improved by applying pulsed dc supply voltage across the ionization detector, thereby modifying the sampling of the detectors output current. A unique pulse generator is used to supply pulsed dc to the detector which has variable width and interval adjust features that allows up to 500 V to be applied in pulse widths ranging from about 150 nsec to about dc conditions.

  20. Pulsed helium ionization detection system

    DOEpatents

    Ramsey, R.S.; Todd, R.A.

    1985-04-09

    A helium ionization detection system is provided which produces stable operation of a conventional helium ionization detector while providing improved sensitivity and linearity. Stability is improved by applying pulsed dc supply voltage across the ionization detector, thereby modifying the sampling of the detectors output current. A unique pulse generator is used to supply pulsed dc to the detector which has variable width and interval adjust features that allows up to 500 V to be applied in pulse widths ranging from about 150 nsec to about dc conditions.

  1. 43 CFR 3100.1 - Helium.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Helium. 3100.1 Section 3100.1 Public Lands: Interior Regulations Relating to Public Lands (Continued) BUREAU OF LAND MANAGEMENT, DEPARTMENT OF THE... Helium. The ownership of and the right to extract helium from all gas produced from lands leased...

  2. 43 CFR 3100.1 - Helium.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 43 Public Lands: Interior 2 2014-10-01 2014-10-01 false Helium. 3100.1 Section 3100.1 Public Lands: Interior Regulations Relating to Public Lands (Continued) BUREAU OF LAND MANAGEMENT, DEPARTMENT OF THE... Helium. The ownership of and the right to extract helium from all gas produced from lands leased...

  3. 30 CFR 256.11 - Helium.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 2 2011-07-01 2011-07-01 false Helium. 256.11 Section 256.11 Mineral Resources... Sulphur Management, General § 256.11 Helium. (a) Each lease issued or continued under these regulations... of and the right to extract helium from all gas produced from the leased area. (b) In case the...

  4. 21 CFR 184.1355 - Helium.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Helium. 184.1355 Section 184.1355 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN... Substances Affirmed as GRAS § 184.1355 Helium. (a) Helium (empirical formula He, CAS Reg. No. 7440-59-7) is...

  5. 21 CFR 582.1355 - Helium.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Helium. 582.1355 Section 582.1355 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS... Helium. (a) Product. Helium. (b) Conditions of use. This substance is generally recognized as safe...

  6. 21 CFR 582.1355 - Helium.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Helium. 582.1355 Section 582.1355 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS... Helium. (a) Product. Helium. (b) Conditions of use. This substance is generally recognized as safe...

  7. 43 CFR 3100.1 - Helium.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 43 Public Lands: Interior 2 2012-10-01 2012-10-01 false Helium. 3100.1 Section 3100.1 Public Lands: Interior Regulations Relating to Public Lands (Continued) BUREAU OF LAND MANAGEMENT, DEPARTMENT OF THE... Helium. The ownership of and the right to extract helium from all gas produced from lands leased...

  8. 30 CFR 556.11 - Helium.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 2 2013-07-01 2013-07-01 false Helium. 556.11 Section 556.11 Mineral Resources... § 556.11 Helium. (a) Each lease issued or continued under these regulations shall be subject to a... helium from all gas produced from the leased area. (b) In case the United States elects to take...

  9. 21 CFR 582.1355 - Helium.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Helium. 582.1355 Section 582.1355 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS... Helium. (a) Product. Helium. (b) Conditions of use. This substance is generally recognized as safe...

  10. 30 CFR 556.11 - Helium.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 2 2014-07-01 2014-07-01 false Helium. 556.11 Section 556.11 Mineral Resources... § 556.11 Helium. (a) Each lease issued or continued under these regulations shall be subject to a... helium from all gas produced from the leased area. (b) In case the United States elects to take...

  11. 30 CFR 556.11 - Helium.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 2 2012-07-01 2012-07-01 false Helium. 556.11 Section 556.11 Mineral Resources... § 556.11 Helium. (a) Each lease issued or continued under these regulations shall be subject to a... helium from all gas produced from the leased area. (b) In case the United States elects to take...

  12. 43 CFR 3100.1 - Helium.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 43 Public Lands: Interior 2 2013-10-01 2013-10-01 false Helium. 3100.1 Section 3100.1 Public Lands: Interior Regulations Relating to Public Lands (Continued) BUREAU OF LAND MANAGEMENT, DEPARTMENT OF THE... Helium. The ownership of and the right to extract helium from all gas produced from lands leased...

  13. 21 CFR 184.1355 - Helium.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Helium. 184.1355 Section 184.1355 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) DIRECT FOOD....1355 Helium. (a) Helium (empirical formula He, CAS Reg. No. 7440-59-7) is a colorless,...

  14. 21 CFR 582.1355 - Helium.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Helium. 582.1355 Section 582.1355 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS... Helium. (a) Product. Helium. (b) Conditions of use. This substance is generally recognized as safe...

  15. 21 CFR 184.1355 - Helium.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Helium. 184.1355 Section 184.1355 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN... Substances Affirmed as GRAS § 184.1355 Helium. (a) Helium (empirical formula He, CAS Reg. No. 7440-59-7) is...

  16. 21 CFR 184.1355 - Helium.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Helium. 184.1355 Section 184.1355 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN... Substances Affirmed as GRAS § 184.1355 Helium. (a) Helium (empirical formula He, CAS Reg. No. 7440-59-7) is...

  17. 21 CFR 184.1355 - Helium.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Helium. 184.1355 Section 184.1355 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN... Substances Affirmed as GRAS § 184.1355 Helium. (a) Helium (empirical formula He, CAS Reg. No. 7440-59-7) is...

  18. 21 CFR 582.1355 - Helium.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Helium. 582.1355 Section 582.1355 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS... Helium. (a) Product. Helium. (b) Conditions of use. This substance is generally recognized as safe...

  19. Multipurpose top for liquid helium Dewar

    NASA Technical Reports Server (NTRS)

    Murphy, R. S.; Anderholm, J. R.

    1972-01-01

    Multipurpose top was fabricated for liquid helium Dewar flask which guards against flash vaporization of liquid helium and allows boiling temperature of liquid helium to be lowered by reduction of ambient pressure in Dewar flask. Device is rugged and simple, and does not require frequent calibrations or adjustments.

  20. Applying the helium ionization detector in chromatography

    NASA Technical Reports Server (NTRS)

    Gibson, E. K.; Andrawes, F. F.; Brazell, R. S.

    1981-01-01

    High noise levels and oversensitivity of helium detector make flame-ionization and thermal-conductivity detectors more suitable for chromotography. Deficiencies are eliminated by modifying helium device to operate in saturation rather than multiplication mode. Result is low background current, low noise, high stability, and high sensitivity. Detector analyzes halocarbons, hydrocarbons, hydrogen cyanide, ammonia, and inorganics without requiring expensive research-grade helium.

  1. Why Helium Ends in "-Ium"

    ERIC Educational Resources Information Center

    Jensen, William B.; Holme, Thomas; Cooper, Melanie; White, Carol

    2004-01-01

    Edward Frankland and Norman Lockyer researched upon a gaseous spectra in relation to the physical constitution of the sun and named it as "helium" (from Greek "helios" meaning "sun"). Since Lockyer apparently never formally proposed the name in print, it is not known why he chose to use a metallic end "ium".

  2. Applicability of Henry's Law to helium solubility in olivine

    NASA Astrophysics Data System (ADS)

    Jackson, C.; Parman, S. W.; Kelley, S. P.; Cooper, R. F.

    2013-12-01

    Applicability of Henry's Law to helium solubility in olivine We have experimentally determined helium solubility in San Carlos olivine across a range of helium partial pressures (PHe) with the goal of quantifying how noble gases behave during partial melting of peridotite. Helium solubility in olivine correlates linearly with PHe between 55 and 1680 bar. This linear relationship suggests Henry's Law is applicable to helium dissolution into olivine up to 1680 bar PHe, providing a basis for extrapolation of solubility relationships determined at high PHe to natural systems. This is the first demonstration of Henry's Law for helium dissolution into olivine. Averaging all the data of the PHe series yields a Henry's coefficient of 3.8(×3.1)×10-12 mol g-1 bar-1. However, the population of Henry's coefficients shows a positive skew (skewness = 1.17), i.e. the data are skewed to higher values. This skew is reflected in the large standard deviation of the population of Henry's coefficients. Averaging the median values from each experiment yields a lower Henry's coefficient and standard deviation: 3.2(× 2.3)×10-12 mol g-1 bar-1. Combining the presently determined helium Henry's coefficient for olivine with previous determinations of helium Henry's coefficients for basaltic melts (e.g. 1) yields a partition coefficient of ~10-4. This value is similar to previous determinations obtained at higher PHe (2). The applicability of Henry's Law here suggests helium is incorporated onto relatively abundant sites within olivine that are not saturated by 1680 bar PHe or ~5×10-9 mol g-1. Large radius vacancies, i.e. oxygen vacancies, are energetically favorable sites for noble gas dissolution (3). However, oxygen vacancies are not abundant enough in San Carlos olivine to account for this solubility (e.g. 4), suggesting the 3x10-12 mol g-1 bar-1 Henry's coefficient is associated with interstitial dissolution of helium. Helium was dissolved into olivine using an externally heated

  3. Variable helium diffusion characteristics in fluorite

    NASA Astrophysics Data System (ADS)

    Wolff, R.; Dunkl, I.; Kempe, U.; Stockli, D.; Wiedenbeck, M.; von Eynatten, H.

    2016-09-01

    Precise analysis of the diffusion characteristics of helium in fluorite is crucial for establishing the new fluorite (U-Th-Sm)/He thermochronometer (FHe), which potentially provides a powerful tool for dating ore deposits unsuitable for the application of conventional geochronometers. Incremental helium outgassing experiments performed on fluorites derived from a spectrum of geological environments suggest a thermally activated volume diffusion mechanism. The diffusion behaviour is highly variable and the parameters range between log D0/a2 = 0.30 ± 0.27-7.27 ± 0.46 s-1 and Ea = 96 ± 3.5-182 ± 3.8 kJ/mol. Despite the fact that the CaF2 content of natural fluorites in most cases exceeds 99 weight percent, the closure temperature (Tc) of the fluorite (U-Th-Sm)/He thermochronometer as calculated from these diffusion parameters varies between 46 ± 14 °C and 169 ± 9 °C, considering a 125 μm fragment size. Here we establish that minor substitutions of calcium by rare earth elements and yttrium (REE + Y) and related charge compensation by sodium, fluorine, oxygen and/or vacancies in the fluorite crystal lattice have a significant impact on the diffusivity of helium in the mineral. With increasing REE + Y concentrations F vacancies are reduced and key diffusion pathways are narrowed. Consequently, a higher closure temperature is to be expected. An empirical case study confirms this variability: two fluorite samples from the same deposit (Horni Krupka, Czech Republic) with ca. 170 °C and ca. 43 °C Tc yield highly different (U-Th-Sm)/He ages of 290 ± 10 Ma and 79 ± 10 Ma, respectively. Accordingly, the fluorite sample with the high Tc could have quantitatively retained helium since the formation of the fluorite-bearing ores in the Permian, despite subsequent Mesozoic burial and associated regional hydrothermal heating. In contrast, the fluorite with the low Tc yields a Late Cretaceous age close to the apatite fission track (AFT) and apatite (U-Th)/He ages (AHe

  4. Cycle design for the ISABELLE helium refrigerator

    SciTech Connect

    Brown, D.P.; Schlafke, A.P.; Wu, K.C.; Moore, R.W.

    1981-01-01

    The superconducting magnets for the ISABELLE storage ring/accelerator are designed to be operated at 3.8/sup 0/K using a forced-flow supercritical helium cooling system. The ISABELLE refrigerator has been designed subject to these special requirements. The design output is 13.65 KW of refrigeration below 4.2/sup 0/K (for cooling the magnet and distribution system), 55 KW at 55/sup 0/K (to cool heat shields for the whole system) and 100 g/s of liquefaction (for magnet power leads cooling). The system incorporates a subcooler section that produces liquid helium at 5.3 atm and 2.6 K and circulates it through the loads, and a Claude-type main refrigerator section. The main refrigerator section has five stages of cooling, with four of them below liquid nitrogen temperature. Liquid nitrogen precooling is not used. With 60% isothermal compressors the efficiency of the refrigerator system will be about 26% of Carnot.

  5. A Cryogen Recycler with Pulse Tube Cryocooler for Recondensing Helium and Nitrogen

    NASA Astrophysics Data System (ADS)

    Wang, C.; Lichtenwalter, B.

    2015-12-01

    We have developed a cryogen recycler using a 4 K pulse tube cryocooler for recondensing helium and nitrogen in a NMR magnet. The liquid helium cooled NMR magnet has a liquid nitrogen cooled radiation shield. The magnet boils off 0.84 L/day of liquid helium and 6 L/day of liquid nitrogen. The recycler is designed with both a liquid helium return tube and a liquid nitrogen return tube, which are inserted into the fill ports of liquid helium and nitrogen. Therefore the recycler forms closed loops for helium and nitrogen. A two-stage 4 K pulse tube cryocooler, Cryomech model PT407 (0.7W at 4.2 K), is selected for the recycler. The recycler was first tested with a Cryomech's test cryostat and resulted in the capacities of recondensing 8.2 L/day of nitrogen and liquefying 4 L/day of helium from room temperature gas. The recycler has been installed in the NMR magnet at University of Sydney since August, 2014 and continuously maintains a zero boil off for helium and nitrogen.

  6. Transport simulations of the ignited ITER with high helium fraction

    NASA Astrophysics Data System (ADS)

    Becker, G.

    1994-04-01

    Computer simulations with special versions of the one dimensional BALDUR predictive transport code are carried out to investigate the particle confinement of helium and hydrogen, the energy confinement and the burn control in the high density scenario of the ITER (CDA) physics phase. The code uses empirical transport coefficients for ELMy H mode plasmas, an improved model of the scrape-off layer (SOL), an impurity radiation model for helium and iron, and fast burn control by neutral beam injection feedback. A self-sustained thermonuclear burn is achieved for hundreds of seconds. The necessary radiation corrected energy confinement time τE is found to be 4.2 s, which is attainable according to the ITER H mode scaling. In the ignited ITER, a significant dilution of the DT fuel by helium takes place. Steady state helium fractions of up to 8% are obtained, which are found to be compatible with self-sustained burn. The SOL model yields self-consistent electron densities and temperatures at the separatrix (ne = 5.8 × 1019 m-3, Te = 80 eV)

  7. Approximating the Helium Wavefunction in Positronium-Helium Scattering

    NASA Technical Reports Server (NTRS)

    DiRienzi, Joseph; Drachman, Richard J.

    2003-01-01

    In the Kohn variational treatment of the positronium- hydrogen scattering problem the scattering wave function is approximated by an expansion in some appropriate basis set, but the target and projectile wave functions are known exactly. In the positronium-helium case, however, a difficulty immediately arises in that the wave function of the helium target atom is not known exactly, and there are several ways to deal with the associated eigenvalue in formulating the variational scattering equations to be solved. In this work we will use the Kohn variational principle in the static exchange approximation to d e t e e the zero-energy scattering length for the Ps-He system, using a suite of approximate target functions. The results we obtain will be compared with each other and with corresponding values found by other approximation techniques.

  8. Helium isotope characteristics of Andean geothermal fluids and lavas

    NASA Astrophysics Data System (ADS)

    Hilton, D. R.; Hammerschmidt, K.; Teufel, S.; Friedrichsen, H.

    1993-12-01

    The first comprehensive helium isotope survey of the Andes is reported here. We have sampled geothermal fluids and phyric lava flows from the Southern (svz) and Central (cvz) Volcanic Zones, the volcanically active Puna region and the Precordillera, Salta Basin, Longitudinal Valley and the aseismic region between the two volcanic zones. Although the active areas are characterized by significant differences in crustal age and thickness, the svz, cvz and Puna are characterized by a wide and overlapping range in He-3/He-4 ratios (for fluids and phenocrysts) from predominantly radiogenic values to close to the Mid-Ocean Ridge Basalt (MORB) ratio. The measured ranges in He-3/He-4 ratios (R) (reported normalised to the air He-3/He-4 -- R(sub A)) are: svz (0.18 less than R/R(sub A) less than 6.9); cvz (0.82 less than R/R(sub A) less than 6.0); and Puna (1.8 less than R/R(sub A) less than 5.4). Modification of magmatic He-3/He-4 ratios by water/rock interactions (fluids) or post-eruptive grow-in of radiogenic He-4 or preferential diffusive loss of He-3 (phenocrysts) is considered unlikely; this means that the wide range reflects the helium isotope characteristics of magma bodies in the Andean crust. The mechanism controlling the He-3/He-4 ratios appears to be a mixing between mantle (MORB-like) helium and a radiogenic helium component derived from radioactive decay within the magma (magma aging) and/or interaction with He-4-rich country rock: a process expected to be influenced by pre-eruptive degassing of the mantle component. Assimilation of lower crust is also capable of modifying He-3/He-4 ratios, albeit to a much lesser extent. However, it is possible that the highest measured values in each zone were established by the addition of lower crustal radiogenic helium to MORB helium. In this case, the higher 'base level' ratios of the svz would reflect the younger crustal structure of this region. In contrast to helium, there is no overlap in the Sr or Pb isotope

  9. Confined helium on Lagrange meshes.

    PubMed

    Baye, D; Dohet-Eraly, J

    2015-12-21

    The Lagrange-mesh method has the simplicity of a calculation on a mesh and can have the accuracy of a variational method. It is applied to the study of a confined helium atom. Two types of confinement are considered. Soft confinements by potentials are studied in perimetric coordinates. Hard confinement in impenetrable spherical cavities is studied in a system of rescaled perimetric coordinates varying in [0,1] intervals. Energies and mean values of the distances between electrons and between an electron and the helium nucleus are calculated. A high accuracy of 11 to 15 significant figures is obtained with small computing times. Pressures acting on the confined atom are also computed. For sphere radii smaller than 1, their relative accuracies are better than 10(-10). For larger radii up to 10, they progressively decrease to 10(-3), still improving the best literature results. PMID:25732054

  10. Superfluid helium leak sealant study

    NASA Technical Reports Server (NTRS)

    Vorreiter, J. W.

    1981-01-01

    Twenty-one leak specimens were fabricated in the ends of stainless steel and aluminum tubes. Eighteen of these tubes were coated with a copolymer material to seal the leak. The other three specimens were left uncoated and served as control specimens. All 21 tubes were cold shocked in liquid helium 50 times and then the leak rate was measured while the tubes were submerged in superfluid helium at 1.7 K. During the cold shocks two of the coated specimens were mechanically damaged and eliminated from the test program. Of the remaining 16 coated specimens one suffered a total coating failure and resulting high leak rate. Another three of the coated specimens suffered partial coating failures. The leak rates of the uncoated specimens were also measured and reported. The significance of various leak rates is discussed in view of the infrared astronomical satellite (IRAS) Dewar performance.

  11. Superfluid Helium Tanker (SFHT) study

    NASA Technical Reports Server (NTRS)

    Eberhardt, Ralph N.; Dominick, Sam M.; Anderson, John E.; Gille, John P.; Martin, Tim A.; Marino, John S.; Paynter, Howard L.; Traill, R. Eric; Herzl, Alfred; Gotlib, Sam

    1988-01-01

    Replenishment of superfluid helium (SFHe) offers the potential of extending the on-orbit life of observatories, satellite instruments, sensors and laboratories which operate in the 2 K temperature regime. A reference set of resupply customers was identified as representing realistic helium servicing requirements and interfaces for the first 10 years of superfluid helium tanker (SFHT) operations. These included the Space Infrared Telescope Facility (SIRTF), the Advanced X-ray Astrophysics Facility (AXAF), the Particle Astrophysics Magnet Facility (Astromag), and the Microgravity and Materials Processing Sciences Facility (MMPS)/Critical Point Phenomena Facility (CPPF). A mixed-fleet approach to SFHT utilization was considered. The tanker permits servicing from the Shuttle cargo bay, in situ when attached to the OMV and carried to the user spacecraft, and as a depot at the Space Station. A SFHT Dewar ground servicing concept was developed which uses a dedicated ground cooling heat exchanger to convert all the liquid, after initial fill as normal fluid, to superfluid for launch. This concept permits the tanker to be filled to a near full condition, and then cooled without any loss of fluid. The final load condition can be saturated superfluid with any desired ullage volume, or the tank can be totally filed and pressurized. The SFHT Dewar and helium plumbing system design has sufficient component redundancy to meet fail-operational, fail-safe requirements, and is designed structurally to meet a 50 mission life usage requirement. Technology development recommendations were made for the selected SFHT concept, and a Program Plan and cost estimate prepared for a phase C/D program spanning 72 months from initiation through first launch in 1997.

  12. Laser Cooling of Metastable Helium

    NASA Astrophysics Data System (ADS)

    Chuang, Ti.

    An experiment on the laser cooling of a metastable helium beam has been carried out. This experiment is appropriate to be described theoretically under a semiclassical framework. The experiment is the first phase of a large experimental project, whose ultimate goal is to investigate the behavior of laser -cooled metastable helium atoms in the quantum mechanical domain. This first phase is to provide the foundation for the second phase, which will be described in a full quantum mechanical framework. To reach this goal, an atomic beam source and a detection and data acquisition system were designed and constructed to be used in both phases. A laser system that is necessary for the first phase was also designed and constructed. This experiment was designed so that the studies of the atomic behavior, both in the semiclassical and quantum mechanical regions, can be investigated almost simultaneously. This experiment mainly consists of a one-dimensional transverse Doppler cooling of a metastable helium beam. The theory of Doppler cooling, based upon previous work of others, is discussed in this thesis as well. A final velocity width (HWHM) of ~0.62 m/s has been achieved, which is about 2.5 times larger than the Doppler velocity predicted by the theory. The two most likely reasons for not obtaining the Doppler velocity have been carefully examined. Sub-Doppler cooling of the helium beam was also tried, but was unsuccessful. It is our belief that the very same reasons prevent us from achieving sub -Doppler cooling as well.

  13. Detecting scintillations in liquid helium

    NASA Astrophysics Data System (ADS)

    Huffman, P. R.; McKinsey, D. N.

    2013-09-01

    We review our work in developing a tetraphenyl butadiene (TPB)-based detection system for a measurement of the neutron lifetime using magnetically confined ultracold neutrons (UCN). As part of the development of the detection system for this experiment, we studied the scintillation properties of liquid helium itself, characterized the fluorescent efficiencies of different fluors, and built and tested three detector geometries. We provide an overview of the results from these studies as well as references for additional information.

  14. Helium in interplanetary dust particles

    NASA Technical Reports Server (NTRS)

    Nier, A. O.; Schlutter, D. J.

    1993-01-01

    Helium and neon were extracted from fragments of individual stratosphere-collected interplanetary dust particles (IDP's) by subjecting them to increasing temperature by applying short-duration pulses of power in increasing amounts to the ovens containing the fragments. The experiment was designed to see whether differences in release temperatures could be observed which might provide clues as to the asteroidal or cometary origin of the particles. Variations were observed which show promise for elucidating the problem.

  15. Vorticity matching in superfluid helium

    NASA Astrophysics Data System (ADS)

    Samuels, David C.

    1991-12-01

    Recent experiments have rekindled interest in high Reynolds number flows using superfluid helium. In a continuing series of experiments, the flow of helium II through various devices (smooth pipes, corrugated pipes, valves, venturies, turbine flowmeters, and coanda flowmeters for example) was investigated. In all cases, the measured values (typically, mass flow rates and pressure drops) were found to be well described by classical relations for high Reynolds flows. This is unexpected since helium II consists of two interpenetrating fluids; one fluid with nonzero viscosity (the normal fluid) and one with zero viscosity (the superfluid). Only the normal fluid component should directly obey classical relations. Since the experiments listed above only measure the external behavior of the flow (i.e., pressure drops over devices), there is a great deal of room for interpretation of their results. One possible interpretation is that in turbulent flows the normal fluid and the superfluid velocity fields are somehow 'locked' together, presumably by the mutual friction force between the superfluid vortex filaments and the normal fluid. We refer to this locking together of the two fluids as 'vorticity matching.'

  16. Temperature dependence of the accommodation coefficient of liquid-helium film.

    NASA Technical Reports Server (NTRS)

    Wang, T. G.; Elleman, D. D.; Olli, E. E.; Saffren, M. M.

    1973-01-01

    We have determined the accommodation coefficient, gamma, of a helium film from 1.15 to 4 K by measuring the time constant of a rotating superconducting Nb sphere levitated in vapor and covered with a saturated helium film. The conventional assumption of the phenomenological theory of superfluidity, that the order parameter psi vanishes at the free surface of helium II, implies that gamma, is unity and independent of temperature. We find that gamma, is nearly unity above the lambda point, suffers an abrupt drop close to T-lambda, and gradually levels off to the value of about 0.8 at lower temperatures.

  17. Detection of Lyman-beta and Helium Resonance Radiation in the Night Sky.

    PubMed

    Young, J M; Carruthers, G R; Holmes, J C; Johnson, C Y; Patterson, N P

    1968-05-31

    A rocket-borne photometer has detected far ultraviolet night glow radiations that are identified as Lyman-beta (HI 1026 angstroms), and the helium lines at 304 or 584 angstroms, or at both. At an altitude of 227 kilometers the measured intensity for Lyman-beta was about 10 rayleighs. The discrimination characteristics of the broad-band helium radiation filter give helium line intensities, at 227 kilometers, of 4.8 and 12 rayleighs, respectively, pending identification of the wavelength of the radiation as 304 or 584 angstroms. These ultraviolet radiations appear sufficient to maintain the night E and F(1) regions of the ionosphere. PMID:17768892

  18. Variation in Atmospheric Helium Isotopes

    NASA Astrophysics Data System (ADS)

    Mabry, J. C.; Marty, B.; Burnard, P.; Blard, P.

    2010-12-01

    Anthropogenic activity such as oil and gas exploitation releases crustal helium, which has excess 4He compared to atmospheric helium. This may give rise to both spatial and temporal variations in the atmospheric 3He/4He. Helium is present in trace quantities in the air (5 ppm) and has a very low ratio (3He/4Heair = 1.38 x 10-6), consequently high precision measurements of atmospheric He presents a significant analytical challenge. Recent work by Sano et al. [1] has endeavored to experimentally quantify these potential variations in the atmospheric 3He/4He by measuring the helium isotopes from air samples collected around the globe and from samples of ancient trapped atmosphere. Their results indicate an increase in the atmospheric 3He/4He from northern to southern latitudes of the order 2 - 4 ‰, which they attribute to greater use of fossil fuels in the northern hemisphere. However, since most of their data points overlap at the 2-3 ‰ (2σ) level, additional measurements (with increased precision if possible) are needed. We have constructed an automated extraction line dedicated to measuring He in samples of air which can rapidly switch between measuring aliquots of sample with standards. It additionally features an adjustable bellows on the sample aliquot volume that enables us to adjust the size of a sample aliquot to precisely match the standard, eliminating biases arising from nonlinear pressure effects in the mass spectrometer. The measurements are made using a Helix SFT multi-collector mass spectrometer. At present, repeat measurements of 3He/4He from our standard (purified air) have a reproducibility of 2‰ (2σ), while measurements of local (Nancy, France) air samples have a reproducibility of 3He/4He of 3‰ (2σ), which are at a similar level to the uncertainties reported by Sano. Modifications are underway to improve 3He measurements which are the principal source of error. We have collected atmospheric samples from around the globe over a wide

  19. Thermodynamic properties of hydrogen-helium plasmas.

    NASA Technical Reports Server (NTRS)

    Nelson, H. F.

    1972-01-01

    Calculation of the thermodynamic properties of an atomic hydrogen-helium plasma for postulated conditions present in a stagnation shock layer of a spacecraft entering the atmosphere of Jupiter. These properties can be used to evaluate transport properties, to calculate convective heating, and to investigate nonequilibrium behavior. The calculations have been made for temperatures from 10,000 to 100,000 K, densities of 10 to the minus 7th and .00001 g cu cm, and three plasma compositions: pure hydrogen, 50% hydrogen/50% helium, and pure helium. The shock layer plasma consists of electrons, protons, atomic hydrogen, atomic helium, singly ionized helium, and doubly atomized helium. The thermodynamic properties which have been investigated are: pressure, average molecular weight, internal energy, enthalpy, entropy, specific heat, and isentropic speed of sound. A consistent model was used for the reduction of the ionization potential in the calculation of the partition functions.

  20. On charged impurity structures in liquid helium

    NASA Astrophysics Data System (ADS)

    Pelmenev, A. A.; Krushinskaya, I. N.; Bykhalo, I. B.; Boltnev, R. E.

    2016-03-01

    The thermoluminescence spectra of impurity-helium condensates (IHC) submerged in superfluid helium have been observed for the first time. Thermoluminescence of impurity-helium condensates submerged in superfluid helium is explained by neutralization reactions occurring in impurity nanoclusters. Optical spectra of excited products of neutralization reactions between nitrogen cations and thermoactivated electrons were rather different from the spectra observed at higher temperatures, when the luminescence due to nitrogen atom recombination dominates. New results on current detection during the IHC destruction are presented. Two different mechanisms of nanocluster charging are proposed to describe the phenomena observed during preparation and warm-up of IHC samples in bulk superfluid helium, and destruction of IHC samples out of liquid helium.

  1. 43 CFR 16.2 - Applications for helium disposition agreements.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 43 Public Lands: Interior 1 2012-10-01 2011-10-01 true Applications for helium disposition... HELIUM § 16.2 Applications for helium disposition agreements. The application for a helium disposition... Secretary to determine that the proposal will conserve helium that will otherwise be wasted, drained,...

  2. 43 CFR 16.2 - Applications for helium disposition agreements.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 43 Public Lands: Interior 1 2013-10-01 2013-10-01 false Applications for helium disposition... HELIUM § 16.2 Applications for helium disposition agreements. The application for a helium disposition... Secretary to determine that the proposal will conserve helium that will otherwise be wasted, drained,...

  3. 43 CFR 16.2 - Applications for helium disposition agreements.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 43 Public Lands: Interior 1 2014-10-01 2014-10-01 false Applications for helium disposition... HELIUM § 16.2 Applications for helium disposition agreements. The application for a helium disposition... Secretary to determine that the proposal will conserve helium that will otherwise be wasted, drained,...

  4. 43 CFR 16.2 - Applications for helium disposition agreements.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 1 2011-10-01 2011-10-01 false Applications for helium disposition... HELIUM § 16.2 Applications for helium disposition agreements. The application for a helium disposition... Secretary to determine that the proposal will conserve helium that will otherwise be wasted, drained,...

  5. 43 CFR 16.2 - Applications for helium disposition agreements.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 43 Public Lands: Interior 1 2010-10-01 2010-10-01 false Applications for helium disposition... HELIUM § 16.2 Applications for helium disposition agreements. The application for a helium disposition... Secretary to determine that the proposal will conserve helium that will otherwise be wasted, drained,...

  6. Energy, helium, and the future: II

    SciTech Connect

    Krupka, M.C.; Hammel, E.F.

    1980-01-01

    The importance of helium as a critical resource material has been recognized specifically by the scientific community and more generally by the 1960 Congressional mandate to institute a long-range conservation program. A major study mandated by the Energy Reorganization Act of 1974 resulted in the publication in 1975 of the document, The Energy-Related Applications of Helium, ERDA-13. This document contained a comprehensive review and analysis relating to helium resources and present and future supply/demand relationships with particular emphasis upon those helium-dependent energy-related technologies projected to be implemented in the post-2000 year time period, e.g., fusion. An updated overview of the helium situation as it exists today is presented. Since publication of ERDA-13, important changes in the data base underlying that document have occurred. The data have since been reexamined, revised, and new information included. Potential supplies of helium from both conventional and unconventional natural gas resources, projected supply/demand relationships to the year 2030 based upon a given power-generation scenario, projected helium demand for specific energy-related technologies, and the supply options (national and international) available to meet that demand are discussed. An updated review will be given of the energy requirements for the extraction of helium from natural gas as they relate to the concentration of helium. A discussion is given concerning the technical and economic feasibility of several methods available both now and conceptually possible, to extract helium from helium-lean natural gas, the atmosphere, and outer space. Finally, a brief review is given of the 1980 Congressional activities with respect to the introduction and possible passage of new helium conservation legislation.

  7. Helium isotopic abundance variation in nature

    SciTech Connect

    Holden, N.E.

    1993-08-01

    The isotopic abundance of helium in nature has been reviewed. This atomic weight value is based on the value of helium in the atmosphere, which is invariant around the world and up to a distance of 100,000 feet. Helium does vary in natural gas, volcanic rocks and gases, ocean floor sediments, waters of various types and in radioactive minerals and ores due to {alpha} particle decay of radioactive nuclides.

  8. Rogue Mantle Helium and Neon

    NASA Astrophysics Data System (ADS)

    Albarede, F.

    2007-12-01

    The canonical view of He isotope geochemistry holds that high 3He/4He ratios in basalts fingerprints undegassed mantle sources. Hawaiian basalts with unradiogenic He with 3He/4He up to 30 RA are therefore seen as originating from parts of the mantle that is still primordial, at least much more so than MORB mantle (3He/4He ~ 8 RA). This view was strongly reinforced by the discovery of solar and even planetary Ne components in oceanic basalts and gas wells. The canonical view, however, conflicts with multiple observations on ocean islands, notably Hawaiian basalts: the correlation of {187}Os/{186}Os with δ 18O combined with the presence of unusually radiogenic Hf isotope compositions for a given Nd isotope composition and the correlation between Hf and Pb isotopes are all features strongly reminiscent of ancient subducted oceanic crust and pelagic sediments in the source of the Hawaiian plume. These conflicting observations beg the question of how Hawaiian basalts, which carry the embodiment of a primordial gas signature, at the same time can provide such strong evidence of surface material recycling. I here suggest and alternative model that uses the marble cake paradigm and Shuster et al.'s data on olivine. A solution to this conundrum lies in an analogy with oil genesis: 3He and Ne do not reside in the low-melting point peridotites in which they were originally hosted but rather migrated since early in Earth history into refractory 'reservoir' rocks. Since there can be no free gas phase percolating at pressures in excess of olivine carbonation at ~3 GPa, He must be largely redistributed by diffusion. The time scale of diffusion is the defining parameter: although over billions of years 3He diffuses across large distances, melting events are too short to efficiently strip residual refractory rocks from their high-3He/4He component. Assuming that melts begin forming over the uppermost 100 km with an upwelling rate of 10 m y-1 in plume conduits and 10 cm y-1 under

  9. Radioactive transitions in the helium isoelectronic sequence

    NASA Technical Reports Server (NTRS)

    Dalgarno, A.

    1971-01-01

    The principles of the atomic spectrum theory are used to quantitatively analyze radiation transitions in two-electron helium-like atomic systems. Quantum theoretical methods, describing absorption and emission of a single photon in a radiative transition between two stationary states of an atomic system, reproduced the energy level diagram for the low lying states of helium. Reliable values are obtained from accurate variationally determined two-electron nonrelativistic wave functions for radiative transition probabilities of 2 3p states in the helium isoelectric sequence, and for the 2 1s and 2 3s1 states of the helium sequence.

  10. Helium-3 emission related to volcanic activity

    SciTech Connect

    Sano, Y.; Nakamura, Y.; Wakita, H.; Urabe, A.; Tominaga, T.

    1984-04-13

    The helium-3/helium-4 ratio in bubbling gases from ten hot springs located around Mount Ontake, an active volcano in central Japan, ranges from 1.71 R/sub atm/ (1.71 times the atmospheric ratio of 1.40 x 10/sup -6/) to 6.15 R/sub atm/. The value of the ratio decreases with distance from the central cone of the volcano. Such a tendency may be a characteristic of helium-3 emission in volcanic areas and suggests more primitive helium-3 is carried with fluid flowing through a conduit during volcanic activity. 6 references, 1 figure, 1 table.

  11. 43 CFR 3195.20 - Who must purchase major helium requirements from Federal helium suppliers?

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 43 Public Lands: Interior 2 2013-10-01 2013-10-01 false Who must purchase major helium requirements from Federal helium suppliers? 3195.20 Section 3195.20 Public Lands: Interior Regulations Relating... (3000) HELIUM CONTRACTS Federal Agency Requirements § 3195.20 Who must purchase major...

  12. 43 CFR 3195.20 - Who must purchase major helium requirements from Federal helium suppliers?

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 43 Public Lands: Interior 2 2012-10-01 2012-10-01 false Who must purchase major helium requirements from Federal helium suppliers? 3195.20 Section 3195.20 Public Lands: Interior Regulations Relating... (3000) HELIUM CONTRACTS Federal Agency Requirements § 3195.20 Who must purchase major...

  13. 43 CFR 3195.20 - Who must purchase major helium requirements from Federal helium suppliers?

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 43 Public Lands: Interior 2 2014-10-01 2014-10-01 false Who must purchase major helium requirements from Federal helium suppliers? 3195.20 Section 3195.20 Public Lands: Interior Regulations Relating... (3000) HELIUM CONTRACTS Federal Agency Requirements § 3195.20 Who must purchase major...

  14. 43 CFR 3195.20 - Who must purchase major helium requirements from Federal helium suppliers?

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Who must purchase major helium requirements from Federal helium suppliers? 3195.20 Section 3195.20 Public Lands: Interior Regulations Relating... (3000) HELIUM CONTRACTS Federal Agency Requirements § 3195.20 Who must purchase major...

  15. 43 CFR 3195.35 - What happens if I have an outstanding obligation to purchase refined helium under a Helium...

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... obligation to purchase refined helium under a Helium Distribution Contract? 3195.35 Section 3195.35 Public... OF THE INTERIOR MINERALS MANAGEMENT (3000) HELIUM CONTRACTS Federal Helium Supplier Requirements § 3195.35 What happens if I have an outstanding obligation to purchase refined helium under a...

  16. 43 CFR 3195.35 - What happens if I have an outstanding obligation to purchase refined helium under a Helium...

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... obligation to purchase refined helium under a Helium Distribution Contract? 3195.35 Section 3195.35 Public... OF THE INTERIOR MINERALS MANAGEMENT (3000) HELIUM CONTRACTS Federal Helium Supplier Requirements § 3195.35 What happens if I have an outstanding obligation to purchase refined helium under a...

  17. 43 CFR 3195.35 - What happens if I have an outstanding obligation to purchase refined helium under a Helium...

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... obligation to purchase refined helium under a Helium Distribution Contract? 3195.35 Section 3195.35 Public... OF THE INTERIOR MINERALS MANAGEMENT (3000) HELIUM CONTRACTS Federal Helium Supplier Requirements § 3195.35 What happens if I have an outstanding obligation to purchase refined helium under a...

  18. 43 CFR 3195.35 - What happens if I have an outstanding obligation to purchase refined helium under a Helium...

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... obligation to purchase refined helium under a Helium Distribution Contract? 3195.35 Section 3195.35 Public... OF THE INTERIOR MINERALS MANAGEMENT (3000) HELIUM CONTRACTS Federal Helium Supplier Requirements § 3195.35 What happens if I have an outstanding obligation to purchase refined helium under a...

  19. Helium distribution in a mantle shear zone from the Josephine Peridotite

    NASA Astrophysics Data System (ADS)

    Recanati, A.; Kurz, M. D.; Warren, J. M.; Curtice, J.

    2012-12-01

    A previous study of oceanic mylonites suggested that peridotite helium concentrations are correlated with the degree of high-temperature ductile deformation in the mantle. In order to test this result, this study combines helium measurements with characterization of the deformation state of harzburgite samples in a small (6 m width) ductile mantle shear zone from the Josephine Peridotite, Oregon, USA. All measurements were made by coupled in vacuo crushing and melting, demonstrating that most of the helium (>80%) resides within the solid phases rather than fluid or melt inclusions. The present study confirms the influence of deformation on helium contents, but only at the highest shear strain (γ>20) are helium contents significantly higher. The highest helium concentration, by roughly a factor of two, is found in the center-most sample, which also has grain size reduction by a factor of ∼4. Dislocations and sub-grain boundaries are present in all samples and do not correlate with helium concentrations. Mineralogy also appears to have a negligible influence in this shear zone, as modal mineralogy is relatively homogeneous, with all samples being harzburgites. These observations suggest that the increase in helium concentration is related to grain size reduction, with grain boundaries proposed as an additional storage site for helium in the mantle. The present data also characterize the isotopic composition of the Josephine Peridotite: 3He/4He=6.7±0.2 Ra (n=33, between 6.3 and 7.1 Ra). The presence of cosmogenic 3He in the matrix is indicated by the helium isotopic composition released by melting: 3He/4He=8.5±0.3 Ra (n=10; from 7.9 to 10.9). This corresponds to an exposure age of 10 Kyr, which is approximately concordant with the end of the last glacial maximum. Very little radiogenic helium is present in the samples, suggesting extremely low uranium and thorium contents ([U]<0.3 ppb). Helium isotope measurements in four samples outside the shear zone suggest

  20. Helium bubble bursting in tungsten

    SciTech Connect

    Sefta, Faiza; Juslin, Niklas; Wirth, Brian D.

    2013-12-28

    Molecular dynamics simulations have been used to systematically study the pressure evolution and bursting behavior of sub-surface helium bubbles and the resulting tungsten surface morphology. This study specifically investigates how bubble shape and size, temperature, tungsten surface orientation, and ligament thickness above the bubble influence bubble stability and surface evolution. The tungsten surface is roughened by a combination of adatom “islands,” craters, and pinholes. The present study provides insight into the mechanisms and conditions leading to various tungsten topology changes, which we believe are the initial stages of surface evolution leading to the formation of nanoscale fuzz.

  1. Helium in Earth's Early Core

    NASA Astrophysics Data System (ADS)

    Jephcoat, A. P.; Bouhifd, M. A.; Heber, V.; Kelley, S. P.

    2006-12-01

    The high 3He/4He ratios for some ocean-island basalts, and more recent observations for solar components of the other rare gases (Ne, Ar and possibly Xe), continue to raise questions on primordial source reservoirs as well as on accretionary and incorporation processes of rare gases. A number of geochemical mantle models have been made to explain the observed 3He/4He ratios, the most popular of which has been an undegassed primordial reservoir. Isotope systematics of other radiogenic elements do not support such an isolated source and changes in the accepted models of mantle convection style have made it harder to rely on the deep mantle as a reservoir. The core has remained a particularly unfavourable location either because of difficulty in constructing a retention mechanism during planetary accretion or simply because of a lack of data: Partitioning studies at pressure are rare and complicated by the difficulty in reproducing not only absolute concentrations, but confinement of gas in high-pressure apparatus and post-run analysis. We present experiments on helium solubility and partitioning between molten silicates and Fe-rich metal liquids up to 16 GPa and 3000 K, with the laser-heated diamond-anvil cell, and the quenched run products analysed by ultra-violet laser ablation mass spectrometry (UVLAMP). Our results indicate a significantly higher partition coefficient for He between molten silicates and Fe-rich alloy liquids of about 10-2 at 16 GPa and 3000~K -- two orders of magnitude more helium is measured in the metal phase compared to the only previous data of Matsuda et al., (1993). The solubility mechanism is varied and involves a distinguishable bulk component and an apparent surface signature (that may be the result of the quench process). Whether surface effects are included or not, the early Earth's core would have incorporated non-negligible amounts of primordial helium if its segregation took place under mid-depth, magma-ocean conditions. The process

  2. Superfluid Helium Tanker (SFHT) study

    NASA Technical Reports Server (NTRS)

    1988-01-01

    The accomplishments and recommendations of the two-phase Superfluid Helium Tanker (SFHT) study are presented. During the first phase of the study, the emphasis was on defining a comprehensive set of user requirements, establishing SFHT interface parameters and design requirements, and selecting a fluid subsystem design concept. During the second phase, an overall system design concept was constructed based on appropriate analyses and more detailed definition of requirements. Modifications needed to extend the baseline for use with cryogens other than SFHT have been determined, and technology development needs related to the recommended design have been assessed.

  3. Helium retention properties of plasma facing materials

    NASA Astrophysics Data System (ADS)

    Yanagihara, H.; Yamauchi, Y.; Hino, T.; Hirohata, Y.; Yamashina, T.

    1997-02-01

    In a fusion reactor, the continuous removal of helium from the core plasma is needed in order to sustain the ignition condition. For this purpose, it has been proposed to place helium selective pumping metals, which can trap more helium than hydrogen, in the vicinity of the divertor. In this study, the helium and hydrogen trapping properties of nickel, tungsten, molybdenum, SS 304 and Inconel 625 were examined. Namely, the dependencies of irradiation temperature on the amount of trapped helium and hydrogen were obtained by thermal desorption spectroscopy (TDS), after helium or hydrogen plasma irradiation. In those metals, nickel showed the most suitable selective pumping capability. Nickel had the helium selective pumping property above 100°C. The maximum amount of trapped helium was (2-3) × 10 16He/ cm2 at an irradiation temperature of 200°C and 600°C. The optimum temperature becomes about 600°C when nickel is used for a selective pumping material.

  4. Stability of Helium Clusters during Displacement Cascades

    SciTech Connect

    Yang, Li; Zu, Xiaotao T.; Xiao, H. Y.; Gao, Fei; Heinisch, Howard L.; Kurtz, Richard J.; Wang, Zhiguo; Liu, K. Z.

    2007-02-01

    The interaction of displacement cascades with helium-vacancy clusters is investigated using molecular dynamics simulations. The He-vacancy clusters initially consist of 20 vacancies with a Helium-to-vacancy ratio ranging from 0.2 to 3. The primary knock-on atom (PKA) energy, Ep, varies from 2 keV to 10 keV, and the PKA direction is chosen such that a displacement cascade is able to directly interact with a helium-vacancy cluster. The simulation results show that the effect of displacement cascades on a helium-vacancy cluster strongly depends on both the helium-to-vacancy ratio and the PKA energy. For the same PKA energy, the size of helium-vacancy clusters increases with the He/V ratio, but for the same ratio, the cluster size changes more significantly with increasing PKA energy. It has been observed that the He-vacancy clusters can be dissolved when the He/V ratio less than 1, but they are able to re-nucleate during the thermal spike phase, forming small He-V nuclei. When the He/V ratio is larger than 1, the He-V clusters can absorb a number of vacancies produced by displacement cascades, forming larger He-V clusters. These results are discussed in terms of PKA energy, helium-to-vacancy ratio, number of vacancies produced by cascades, and mobility of helium atoms.

  5. Paramagnetic Attraction of Impurity-Helium Solids

    NASA Technical Reports Server (NTRS)

    Bernard, E. P.; Boltnev, R. E.; Khmelenko, V. V.; Lee, D. M.

    2003-01-01

    Impurity-helium solids are formed when a mixture of impurity and helium gases enters a volume of superfluid helium. Typical choices of impurity gas are hydrogen deuteride, deuterium, nitrogen, neon and argon, or a mixture of these. These solids consist of individual impurity atoms and molecules as well as clusters of impurity atoms and molecules covered with layers of solidified helium. The clusters have an imperfect crystalline structure and diameters ranging up to 90 angstroms, depending somewhat on the choice of impurity. Immediately following formation the clusters aggregate into loosely connected porous solids that are submerged in and completely permeated by the liquid helium. Im-He solids are extremely effective at stabilizing high concentrations of free radicals, which can be introduced by applying a high power RF dis- charge to the impurity gas mixture just before it strikes the super fluid helium. Average concentrations of 10(exp 19) nitrogen atoms/cc and 5 x 10(exp 18) deuterium atoms/cc can be achieved this way. It shows a typical sample formed from a mixture of atomic and molecular hydrogen and deuterium. It shows typical sample formed from atomic and molecular nitrogen. Much of the stability of Im-He solids is attributed to their very large surface area to volume ratio and their permeation by super fluid helium. Heat resulting from a chance meeting and recombination of free radicals is quickly dissipated by the super fluid helium instead of thermally promoting the diffusion of other nearby free radicals.

  6. LOX Tank Helium Removal for Propellant Scavenging

    NASA Technical Reports Server (NTRS)

    Chato, David J.

    2009-01-01

    System studies have shown a significant advantage to reusing the hydrogen and oxygen left in these tanks after landing on the Moon in fuel cells to generate power and water for surface systems. However in the current lander concepts, the helium used to pressurize the oxygen tank can substantially degrade fuel cell power and water output by covering the reacting surface with inert gas. This presentation documents an experimental investigation of methods to remove the helium pressurant while minimizing the amount of the oxygen lost. This investigation demonstrated that significant quantities of Helium (greater than 90% mole fraction) remain in the tank after draining. Although a single vent cycle reduced the helium quantity, large amounts of helium remained. Cyclic venting appeared to be more effective. Three vent cycles were sufficient to reduce the helium to small (less than 0.2%) quantities. Two vent cycles may be sufficient since once the tank has been brought up to pressure after the second vent cycle the helium concentration has been reduced to the less than 0.2% level. The re-pressurization process seemed to contribute to diluting helium. This is as expected since in order to raise the pressure liquid oxygen must be evaporated. Estimated liquid oxygen loss is on the order of 82 pounds (assuming the third vent cycle is not required).

  7. Helium in the larderello geothermal fluid

    USGS Publications Warehouse

    D'Amore, F.; Truesdell, A.

    1984-01-01

    A recent survey of helium concentrations in Larderello steam showed that there has been a strong decrease since earlier surveys and that the helium is concentrated in central zones of steam up-flow. The He decline and present distribution are interpreted as being due to the release of stored He produced by production-induced microfracturing. ?? 1984.

  8. Helium solubility and behaviour in uranium dioxide

    NASA Astrophysics Data System (ADS)

    Maugeri, E.; Wiss, T.; Hiernaut, J.-P.; Desai, K.; Thiriet, C.; Rondinella, V. V.; Colle, J.-Y.; Konings, R. J. M.

    2009-03-01

    A set of devices was developed in order to infuse UO2 disks with helium, at high temperature and pressure, to measure the helium infused quantity and from these data to calculate the helium solubility in the UO2 matrix. Samples of UO2 single crystal and UO2 polycrystal were infused at a temperature of 1473 and 1743 K in a helium atmosphere ranging between 50 and 100 MPa. These samples were then annealed and the helium released was measured with a mass spectrometer. From the obtained spectra it was possible to give an interpretation of the helium release mechanism and to calculate its solubility in the UO2 lattice in these specific thermodynamic conditions. Additionally to the helium solubility measurement from infused samples, a 37 years old sample of 238PuO2, retrieved from an old 242Cm radioisotope thermoelectric generator (RTG), containing radiogenic helium, was also measured to widen perspectives of this kind of measurements to damaged sample more representative of spent fuel.

  9. Helium-cooled high temperature reactors

    SciTech Connect

    Trauger, D.B.

    1985-01-01

    Experience with several helium cooled reactors has been favorable, and two commercial plants are now operating. Both of these units are of the High Temperature Graphite Gas Cooled concept, one in the United States and the other in the Federal Republic of Germany. The initial helium charge for a reactor of the 1000 MW(e) size is modest, approx.15,000 kg.

  10. Helium-flow measurement using ultrasonic technique

    NASA Astrophysics Data System (ADS)

    Sondericker, J. H.

    1983-08-01

    The ideal cryogenic instrumentation for the colliding beam accelerator helium distribution system does not add pressure drop to the system, functions over the entire temperature range, has high resolution, and delivers accurate mass flow measurement data. The design and testing of an ultrasonic flowmeter which measures helium flow under different temperatures are described.

  11. Helium Speech: An Application of Standing Waves

    ERIC Educational Resources Information Center

    Wentworth, Christopher D.

    2011-01-01

    Taking a breath of helium gas and then speaking or singing to the class is a favorite demonstration for an introductory physics course, as it usually elicits appreciative laughter, which serves to energize the class session. Students will usually report that the helium speech "raises the frequency" of the voice. A more accurate description of the…

  12. Explosive Hydrogen and Helium Burning in Astrophysical Events.

    NASA Astrophysics Data System (ADS)

    Wallace, Richard Kent

    The nuclear energy generation and nucleosynthesis that occur in hydrogen-rich compositions at temperatures substantially greater than 10('8) K are examined in detail. At these high temperatures, a new kind of nucleosynthetic process (the "rp-process") involving the rapid capture of protons on seed nuclei (or on the products of helium burning in a situation with zero initial metallicity) can lead to the production of heavy elements up to and beyond the iron group with an accompanying energy generation rate greatly modified from that of the (beta)-limited CNO cycle customarily employed in such calculations. New nuclear reaction rates of interest are tabulated, and reaction network calculations are presented to illustrate the application of this process to exploding supermassive stars, accreting neutron stars, novae, and certain chaotic cosmologies. Implications for (gamma)-line astronomy and x-ray burst models are discussed. To further explore the importance of thermonuclear instabilities for accreting neutron stars, the evolution of a 1.41 M(,(CIRCLE)) neutron star accreting both solar and metal-deficient mixtures of hydrogen, helium, and heavy elements at rates ranging from about 10('-11) to 10('-10) M(,(CIRCLE)) per year is examined using a one-dimensional numerical model. The metal deficient compositions may result either from placement of the neutron star in a binary system with a Population II Red Giant or from gravitational settling of heavy ions in the accreted material. For such accretion rates and metallicities, hydrogen burning, mediated by the (beta)-limited CNO cycle, is stable and leads to the accumulation of a thick helium layer with mass 10('23) to 10('25) g and temperature 0.7 (LESSTHEQ) T(,8) (LESSTHEQ) 1.2. Helium ignition occurs under extremely degenerate circumstances and is catastrophically violent. In the lower mass helium shells this runaway is propagated as a convective deflagration; for the thicker layers a detonation front is set up which

  13. Effects of discharge current and voltage on the high density of metastable helium atoms

    NASA Astrophysics Data System (ADS)

    Feng, Xian-Ping; Andruczyk, D.; James, B. W.; Takiyama, K.; Namba, S.; Oda, T.

    2003-05-01

    Both hollow-cathode and Penning-type discharges were adopted to excite helium atoms to a metastable state. Experimental data indicate that Penning discharge is more suitable for generating high fractions of metastables in a low-density helium beam for laser-induced fluorescence technique in measuring electric fields at the edge of a plasma. The metastable density increases with increasing helium gas pressure in the range of 1.33×10-2-66.7Pa. The highest metastable density of 3.8×1016m-3 is observed at a static gas pressure of 66.7Pa. An approximately linear relationship between the density of metastable helium atoms and the plasma discharge current is observed. Magnetic field plays a very important role in producing a high density of metastable atoms in Penning discharge.

  14. Measurements of the helium 584 Å airglow during the Cassini flyby of Venus

    NASA Astrophysics Data System (ADS)

    Gérard, J.-C.; Gustin, J.; Hubert, B.; Gladstone, G. R.; Esposito, L. W.

    2011-10-01

    The helium resonance line at 584 Å has been observed with the UltraViolet Imaging Spectrograph (UVIS) Extreme Ultraviolet channel during the flyby of Venus by Cassini at a period of high solar activity. The brightness was measured along the disk from the morning terminator up to the bright limb near local noon. The mean disk intensity was ∼320 R, reaching ∼700 R at the bright limb. These values are slightly higher than those determined from previous observations. The sensitivity of the 584 Å intensity to the helium abundance is analyzed using recent cross-sections and solar irradiance measurements at 584 Å. The intensity distribution along the UVIS footprint on the disk is best reproduced using the EUVAC solar flux model and the helium density distribution from the VTS3 empirical model. It corresponds to a helium density of 8×106 cm-3 at the level of where the CO2 is 2×1010 cm-3.

  15. Gemini helium closed cycle cooling system

    NASA Astrophysics Data System (ADS)

    Lazo, Manuel; Galvez, Ramon; Rogers, Rolando; Solis, Hernan; Tapia, Eduardo; Maltes, Diego; Collins, Paul; White, John; Cavedoni, Chas; Yamasaki, Chris; Sheehan, Michael P.; Walls, Brian

    2008-07-01

    The Gemini Observatory presents the Helium Closed Cycle Cooling System that provides cooling capacity at cryogenic temperatures for instruments and detectors. It is implemented by running three independent helium closed cycle cooling circuits with several banks of compressors in parallel to continuously supply high purity helium gas to cryocoolers located about 100-120 meters apart. This poster describes how the system has been implemented, the required helium pressures and gas flow to reach cryogenic temperature, the performance it has achieved, the helium compressors and cryocoolers in use and the level of vibration the cryocoolers produce in the telescope environment. The poster also describes the new technology for cryocoolers that Gemini is considering in the development of new instruments.

  16. Cryogenic helium 2 systems for space applications

    NASA Technical Reports Server (NTRS)

    Urban, E.; Katz, L.; Hendricks, J.; Karr, G.

    1978-01-01

    Two cryogenic systems are described which will provide cooling for experiments to be flown on Spacelab 2 in the early 1980's. The first system cools a scanning infrared telescope by the transfer of cold helium gas from a separate superfluid helium storage dewar. The flexible design permits the helium storage dewar and transfer assembly to be designed independent of the infrared experiment. Where possible, modified commerical apparatus is used. The second cryogenic system utilizes a specially designed superfluid dewar in which a superfluid helium experiment chamber is immersed. Each dewar system employs a porous plug as a phase separator to hold the liquid helium within the dewar and provide cold gas to a vent line. To maintain the low vapor pressure of the superfluid, each system requires nearly continuous prelaunch vacuum pump service, and each will vent to space during the Spacelab 2 flight.

  17. Helium Migration Mechanisms in Polycrystalline Uranium Dioxide

    SciTech Connect

    Martin, Guillaume; Desgardin, Pierre; Sauvage, Thierry; Barthe, Marie-France; Garcia, Philippe; Carlot, Gaelle

    2007-07-01

    This study aims at identifying the release mechanisms of helium in uranium dioxide. Two sets of polycrystalline UO{sub 2} sintered samples presenting different microstructures were implanted with {sup 3}He ions at concentrations in the region of 0.1 at.%. Changes in helium concentrations were monitored using two Nuclear Reaction Analysis (NRA) techniques based on the {sup 3}He(d,{alpha}){sup 1}H reaction. {sup 3}He release is measured in-situ during sample annealing at temperatures ranging between 700 deg. C and 1000 deg. C. Accurate helium depth profiles are generated after each annealing stage. Results that provide data for further understanding helium release mechanisms are discussed. It is found that helium diffusion appears to be enhanced above 900 deg. C in the vicinity of grain boundaries possibly as a result of the presence of defects. (authors)

  18. Permeability of Hollow Microspherical Membranes to Helium

    NASA Astrophysics Data System (ADS)

    Zinoviev, V. N.; Kazanin, I. V.; Pak, A. Yu.; Vereshchagin, A. S.; Lebiga, V. A.; Fomin, V. M.

    2016-01-01

    This work is devoted to the study of the sorption characteristics of various hollow microspherical membranes to reveal particles most suitable for application in the membrane-sorption technologies of helium extraction from a natural gas. The permeability of the investigated sorbents to helium and their impermeability to air and methane are shown experimentally. The sorption-desorption dependences of the studied sorbents have been obtained, from which the parameters of their specific permeability to helium are calculated. It has been established that the physicochemical modification of the original particles exerts a great influence on the coefficient of the permeability of a sorbent to helium. Specially treated cenospheres have displayed high efficiency as membranes for selective extraction of helium.

  19. Diffusion of helium isotopes in silicate glasses and minerals: Implications for petrogenesis and geochronology. Doctoral thesis

    SciTech Connect

    Trull, T.W.

    1989-06-01

    Helium diffusivities in basaltic glasses at seafloor temperatures are about 10 to the -16th power sq cm/s suggesting only very low concentration samples will be compromised, and that U/He geochronology of submarine basalts may be feasible. Helium diffusivities at magmatic temperatures are 10 to the -11th power, to 10 to the -8th power sq cm/s in silicate minerals, too low to regionally homogenize helium in the mantle. Helium exchange rates limit xenolith origin depths and transport times. Faster He diffusion in pyroxene than olivine allows diffusive loss to be evaluated. Diffusivities of {sup 3}He produced by cosmic rays in surface rocks are less than 10 to the -20th power sq cm/s in olivine and quartz, suggesting exposure dating will not be limited by helium loss for ages up to 10,000,000 years. Similar conclusions were found for U/{sup 4}He dating of quartz. Part of the {sup 3}He/{sup 4}He variability (.01 to 9 R{sub a}) of island arc basalts from the western Pacific reflects post-eruptive helium addition. In unaltered samples, Kavachi submarine volcano has different {sup 3}He/{sup 4}He (6.9 + or - .2 R{sub a}) than the Woodlark Spreading Center (8-9 R{sub a}). A contribution from subducted Pacific lithosphere may explain this and 87 Sr/86 Sr variations.

  20. Infrared Spectroscopy of HOCl Embedded in Helium Nanodroplets

    NASA Astrophysics Data System (ADS)

    Raston, Paul; Kelloway, Donald; Jäger, Wolfgang

    2012-06-01

    The infrared depletion spectrum of hypochlorous acid (HOCl) embedded in superfluid helium nanodroplets has been measured in the region near 2.8 μm. The spectrum consists of baseline resolved a-type lines and a broad convoluted b-type feature. The a-type lines are asymmetrically skewed in the direction of the band origin, and an analysis of their line shapes based on the chirped damped oscillator function introduced by van Staveren and Apkarian yields a response time of the helium solvent of 1 ns. The b-type lines are much broader due to the greater number of droplet states available for relaxation of the excited rotational states. M. N. van Staveren, and V. A. Apkarian J. Chem. Phys., 132, 054506 (2010).

  1. Neovascular glaucoma after helium ion irradiation for uveal melanoma

    SciTech Connect

    Kim, M.K.; Char, D.H.; Castro, J.L.; Saunders, W.M.; Chen, G.T.; Stone, R.D.

    1986-02-01

    Neovascular glaucoma developed in 22 of 169 uveal melanoma patients treated with helium ion irradiation. Most patients had large melanomas; no eyes containing small melanomas developed anterior segment neovascularization. The mean onset of glaucoma was 14.1 months (range, 7-31 months). The incidence of anterior segment neovascularization increased with radiation dosage; there was an approximately three-fold increase at 80 GyE versus 60 GyE of helium ion radiation (23% vs. 8.5%) (P less than 0.05). Neovascular glaucoma occurred more commonly in larger tumors; the incidence was not affected by tumor location, presence of subretinal fluid, nor rate of tumor regression. Fifty-three percent of patients had some response with intraocular pressures of 21 mmHg or less to a combination of antiglaucoma treatments.

  2. Elastic Electron Scattering from Tritium and Helium-3

    DOE R&D Accomplishments Database

    Collard, H.; Hofstadter, R.; Hughes, E. B.; Johansson, A.; Yearian, M. R.; Day, R. B.; Wagner, R. T.

    1964-10-01

    The mirror nuclei of tritium and helium-3 have been studied by the method of elastic electron scattering. Absolute cross sections have been measured for incident electron energies in the range 110 - 690 MeV at scattering angles lying between 40 degrees and 135 degrees in this energy range. The data have been interpreted in a straightforward manner and form factors are given for the distributions of charge and magnetic moment in the two nuclei over a range of four-momentum transfer squared 1.0 - 8.0 F{sup -2}. Model-independent radii of the charge and magnetic moment distributions are given and an attempt is made to deduce form factors describing the spatial distribution of the protons in tritium and helium-3.

  3. Linear electron chains on the surface of superfluid helium

    NASA Astrophysics Data System (ADS)

    Kovdrya, Yu. Z.; Nikolaenko, V. A.; Gladchenko, S. P.; Sokolov, S. S.

    1998-11-01

    A unique one-dimensional system of linear electron chains on the liquid helium surface is realized experimentally for the first time. This system is created by using the distortion of the helium surface and covering the profiled dielectric substrate in a confining electric field holding electrons in the liquid channels being formed. The carrier mobility in linear electric chains is measured in the temperature interval 0.5-1.8K in confining fields up to 1 kV/cm. It is shown that the electron mobility depends on the purity of the substrate surface. For clean substrates, the mobility increases with decreasing temperature in the entire investigated temperature range. The results of measurements are found to be in accord with the existing theory.

  4. A GM cryocooler with cold helium circulation for remote cooling

    NASA Astrophysics Data System (ADS)

    Wang, Chao; Brown, Ethan

    2014-01-01

    A GM cryocooler with new cold helium circulation system has been developed at Cryomech. A set of check valves connects to the cold heat exchanger to convert a small portion of AC oscillating flow in the cold head to a DC gas flow for circulating cold helium in the remote loop. A cold finger, which is used for remote cooling, is connected to the check valves through a pair of 5 m long vacuum insulated flexible lines. The GM cryocooler, Cryomech model AL125 having 120 W at 80 K, is employed in the testing. The cold finger can provide 50 W at 81 K for the power input of 4.1 kW and 70.5 W at 81.8 K for the power input of 6 kW. This simple and low cost design is very attractive for some applications in the near future.

  5. Optical Forces on Metastable Helium

    NASA Astrophysics Data System (ADS)

    Corder, Christopher Scott

    Optical forces using lasers allow precise control over the motion of atoms. The bichromatic optical force (BF) is unique in its large magnitude and velocity range, arising from the absorption and stimulated emission processes. These properties were used to transversely collimate a beam of metastable helium (He*) using the 23S - 23P transition. The collimation created a very bright beam of He*, allowing experiments of neutral atom lithography. The He* beam was used to pattern material surfaces using a resist-based lithography technique, where the pattern was determined by either mechanical or optical masks. The optical masks produced features with a separation of half the wavelength of the light used. Patterning was successfully demonstrated with both IR and UV optical masks. The etched pattern resolution was ˜ 100 nm and limited by the material surface. Further experiments were performed studying the ability of the bichromatic force to cool. The finite velocity range of the BF allows estimation of a characteristic cooling time which is independent of the excited state lifetime, only depending on the atomic mass and optical transition energy. Past experiments, including the helium collimation used for neutral atom lithography, have demonstrated that the BF can collimate and longitudinally slow atomic beams, but required long interaction times that included many spontaneous emission (SE) events. The effect of SE can be mitigated, and is predicted to not be necessary for BF cooling. Since the BF cooling time is not related to the excited state lifetime, a transition can be chosen such that the cooling time is shorter than the SE cycle time, allowing direct laser cooling on atoms and molecules that do not have cycling transitions. Experiments using the helium 2 3S-3P transition were chosen because the BF cooling time (285 ns) is on the order of the average SE cycle time (260 ns). Numerical simulations of the experimental system were run predicting compression of the

  6. Electric response in superfluid helium

    NASA Astrophysics Data System (ADS)

    Chagovets, Tymofiy V.

    2016-05-01

    We report an experimental investigation of the electric response of superfluid helium that arises in the presence of a second sound standing wave. It was found that the signal of the electric response is observed in a narrow range of second sound excitation power. The linear dependence of the signal amplitude has been derived at low excitation power, however, above some critical power, the amplitude of the signal is considerably decreased. It was established that the rapid change of the electric response is not associated with a turbulent regime generated by the second sound wave. A model of the appearance of the electric response as a result of the oscillation of electron bubbles in the normal fluid velocity field in the second sound wave is presented. Possible explanation for the decrease of the electric response are presented.

  7. Atom lithography with metastable helium

    SciTech Connect

    Allred, Claire S.; Reeves, Jason; Corder, Christopher; Metcalf, Harold

    2010-02-15

    A bright metastable helium (He*) beam is collimated sequentially with the bichromatic force and three optical molasses velocity compression stages. Each He* atom in the beam has 20 eV of internal energy that can destroy a molecular resist assembled on a gold coated silicon wafer. Patterns in the resist are imprinted onto the gold layer with a standard selective etch. Patterning of the wafer with the He{sup *} was demonstrated with two methods. First, a mesh was used to protect parts of the wafer making an array of grid lines. Second, a standing wave of {lambda}=1083 nm light was used to channel and focus the He* atoms into lines separated by {lambda}/2. The patterns were measured with an atomic force microscope establishing an edge resolution of 80 nm. Our results are reliable and repeatable.

  8. Effect of 800 keV argon ions pre-damage on the helium blister formation of tungsten exposed to 60 keV helium ions

    NASA Astrophysics Data System (ADS)

    Chen, Zhe; Han, Wenjia; Yu, Jiangang; Zhu, Kaigui

    2016-04-01

    This study aims to investigate the effect of Ar8+ ions pre-damage on the following He2+ irradiation behavior of polycrystalline tungsten. We compared the irradiation resistance performance against 60 keV He2+ ions of undamaged tungsten samples with that of pre-damaged samples which were preliminarily exposed to 800 keV Ar8+ ions at a fluence of 4 × 1019 ions m-2. The experimental results indicate that the helium blistering of tungsten could be effectively relieved by the Ar8+ ions pre-damage, while the retention of helium around low energy desorption sites in the pre-damaged tungsten was larger than that of the undamaged samples. A strong orientation dependence of blistering had been observed, with the blister occurred preferentially on the surface of grains with normal direction close to <111>. The Ar8+ ions irradiation-induced damage altered the morphology of helium bubbles in tungsten exposed to the following He2+ irradiation significantly. The intensity of helium release peaks at relatively low temperatures (<600 K) was enhanced due to Ar8+ ions pre-damage.

  9. Helium refrigeration considerations for cryomodule design

    SciTech Connect

    Ganni, V.; Knudsen, P.

    2014-01-29

    Many of the present day accelerators are based on superconducting radio frequency (SRF) cavities, packaged in cryo-modules (CM), which depend on helium refrigeration at sub-atmospheric pressures, nominally 2 K. These specialized helium refrigeration systems are quite cost intensive to produce and operate. Particularly as there is typically no work extraction below the 4.5-K supply, it is important that the exergy loss between this temperature level and the CM load temperature(s) be minimized by the process configuration choices. This paper will present, compare and discuss several possible helium distribution process arrangements to support the CM loads.

  10. THE GREEN BANK TELESCOPE H II REGION DISCOVERY SURVEY. IV. HELIUM AND CARBON RECOMBINATION LINES

    SciTech Connect

    Wenger, Trey V.; Bania, T. M.; Balser, Dana S.; Anderson, L. D.

    2013-02-10

    The Green Bank Telescope H II Region Discovery Survey (GBT HRDS) found hundreds of previously unknown Galactic regions of massive star formation by detecting hydrogen radio recombination line (RRL) emission from candidate H II region targets. Since the HRDS nebulae lie at large distances from the Sun, they are located in previously unprobed zones of the Galactic disk. Here, we derive the properties of helium and carbon RRL emission from HRDS nebulae. Our target sample is the subset of the HRDS that has visible helium or carbon RRLs. This criterion gives a total of 84 velocity components (14% of the HRDS) with helium emission and 52 (9%) with carbon emission. For our highest quality sources, the average {sup 4}He{sup +}/H{sup +} abundance ratio by number, (y {sup +}), is 0.068 {+-} 0.023(1{sigma}). This is the same ratio as that measured for the sample of previously known Galactic H II regions. Nebulae without detected helium emission give robust y {sup +} upper limits. There are 5 RRL emission components with y {sup +} less than 0.04 and another 12 with upper limits below this value. These H II regions must have either a very low {sup 4}He abundance or contain a significant amount of neutral helium. The HRDS has 20 nebulae with carbon RRL emission but no helium emission at its sensitivity level. There is no correlation between the carbon RRL parameters and the 8 {mu}m mid-infrared morphology of these nebulae.

  11. Comparison of Carbon and Main Ion Radiation Profiles in Matched Helium and Deuterium Plasmas in JET

    SciTech Connect

    Fenstermacher, M E; Lawson, K D; Porter, G D; Erents, S K; Ingesson, C; Mathews, G F; McCracken, G M; Philipps, V; Pitts, A; Stamp, M F

    2002-05-17

    This paper examines the radiation profiles and corresponding ionization source profiles of various carbon and main plasma ions in matched helium and deuterium L-mode plasmas in JET. Operation in helium should reduce chemical sputtering of carbon substantially compared with deuterium. The radiation intensities from C{sup 1+}, C{sup 2+} and C{sup 3+} in the helium plasmas showed reduction by factors of 8, 10 and 25 respectively along the inner SOL and divertor leg compared with the deuterium cases. However, the emission in the outer divertor leg was less than a factor of 2 lower in helium. Using photon efficiencies calculated by the UEDGE code for the spectrometer lines of sight, the calculated source rates of C{sup 1+} and C{sup 3+} along the inner SOL and inner divertor were reduced by a factors of 4 and 20 respectively in the helium plasmas. In the outer divertor leg the source rate of C{sup 3+} was reduced by a factor of 10 but the C{sup 1+} source rate did not change in helium. These measurements are consistent with a model that chemical sputtering of carbon dominates the source from the inner wall and inner divertor in deuterium L-mode plasmas while physical sputtering appears to dominate the source from the outer divertor.

  12. Helium-neon laser improves skin repair in rabbits.

    PubMed

    Peccin, Maria Stella; Renno, Ana Claudia Muniz; de Oliveira, Flavia; Giusti, Paulo Ricardo; Ribeiro, Daniel Araki

    2012-12-01

    The purpose of this study was to evaluate the influence of helium-neon laser on skin injury in rabbits. For this purpose, 15 New Zealand rabbits underwent bilateral skin damage in leg. Helium-neon laser light, at a fluence of 6 J∕cm2 and wavelength of 632.8 nm, was applied on the left legs (laser group). The right leg lesions (control group) served as negative control. All sections were histopathologically analyzed using HE sections. The results showed little infiltration of inflammatory cells, with proliferation of fibroblasts forming a few fibrous connective tissue after 1 week post-injury. The lesion on the 3rd week was characterized by granulation tissue, which formed from proliferated fibrous connective tissue, congested blood vessels and mild mononuclear cell infiltration. On the 5th week, it was observed that debris material surrounded by a thick layer of connective tissue and dense collage, fibroblasts cells present in the dermis covered by a thick epidermal layer represented by keratinized epithelium. Taken together, our results suggest that helium-neon laser is able to improve skin repair in rabbits at early phases of recovery. PMID:23057697

  13. Global model including multistep ionizations in helium plasmas

    NASA Astrophysics Data System (ADS)

    Oh, Seungju; Lee, Hyo-Chang; Chung, Chin-Wook

    2015-09-01

    Particle and power balance equations including stepwise ionizations are derived and solved in helium plasma. In the balance equations, two metastable states (23S1 in singlet and 21S1 triplet) are considered and followings are obtained. The plasma density linearly increases and electron temperature is relatively in constant value against the absorbed power. It is also found that the contribution to multi-step ionization respect to the single-step ionization is in the range of 8% - 23%, as the gas pressure increases from 10 mTorr to 100 mTorr. There has little variation in the collisional energy loss per electron-ion pair created (Ec). These results indicate that the stepwise ionizations are the minor effect in case of the helium plasma compared to argon plasma. This is because that helium gas has very small collisional cross sections and higher inelastic collision threshold energy resulting in the little variations for the collisional energy loss per electron-ion pair created.

  14. Operating experiences and test results of six cold helium compressors

    NASA Astrophysics Data System (ADS)

    Brown, D. P.; Gibbs, R. J.; Schlafke, A. P.; Sondericker, J. H.; Wu, K. C.

    Three small and three large cold helium centrifugal compressors have been operated at Brookhaven National Laboratory between 1981 and 1986. The three small cold compressors have been installed on a 1000 W refrigerator for testing a string of superconducting magnets and for R and D purposes. The three large units are components of the BNL 24.8 KW refrigerator to be used to provide cooling for the RHIC project. These compressors are used either to circulate a large amount of supercritical helium through a group of magnets or to pump on the helium bath to reduce temperature in the system. One small circulating compressor tested employs tilting-pad gas bearings and is driven by a DC motor. The two small cold vacuum pumps tested use oil bearings and are driven by oil turbines. The three large oil-bearing cold compressors are driven by DC motors through a gear box. A unique feature of the large vacuum pump is the combination of two pumps with a total of four stages on the same shaft. The adiabatic efficiencies are found to be 57% for the large vacuum pumps and close to 50% for the large circulating compressor. Good overall reliability has been experienced.

  15. Properties of vanadium-base alloys irradiated in the dynamic helium charging experiment

    SciTech Connect

    Chung, H.M.; Loomis, B.A.; Smith, D.L.

    1996-02-01

    One property of vanadium-base alloys that is not well understood in terms of their potential use as fusion reactor structural materials is the effect of simultaneous generation of helium and neutron damage. In the present Dynamic Helium Charging Experiment (DHCE), helium was produced uniformly in the specimen at linear rates of {approx} 0.4 to 4.2 appm helium/dpa by the decay of tritium during irradiation to 18--31 dpa at 425--600 C in Li-filled capsules in a sodium-cooled fast reactor. This paper presents results of postirradiation examination and tests of microstructure and mechanical properties of V-5Ti, V-3Ti-1Si, V-8Cr-6Ti, and V-4Cr-4Ti (the latter alloy has been identified as the most promising candidate vanadium alloy). Effects of helium on tensile strength and ductility were insignificant after irradiation and testing at > 420 C. However, postirradiation ductilities at < 250 C were higher than those of the non-DHCE specimens (< 0.1 appm helium), whereas strengths were lower, indicating that different types of hardening centers are produced during DHCE and non-DHCE irradiation. Ductile-brittle transition behavior of the DHCE specimens was also determined from bend tests and fracture appearance of transmission electron microscopy (TEM) disks and broken tensile specimens. No brittle behavior was observed at temperatures > {minus}150 C in DHCE specimens. Predominantly brittle-cleavage fracture morphologies were observed only at {minus}196 C in some specimens that were irradiated to 31 dpa at 425 C during the DHCE. For the helium generation rates in this experiment ({approx} 0.4--4.2 appm He/dpa), grain-boundary coalescence of helium microcavities was negligible and intergranular fracture was not observed.

  16. Helium measurements of pore-fluids obtained from SAFOD drillcore

    SciTech Connect

    Ali, S.; Stute, M.; Torgersen, T.; Winckler, G.; Kennedy, B.M.

    2010-04-15

    {sup 4}He accumulated in fluids is a well established geochemical tracer used to study crustal fluid dynamics. Direct fluid samples are not always collectable; therefore, a method to extract rare gases from matrix fluids of whole rocks by diffusion has been adapted. Helium was measured on matrix fluids extracted from sandstones and mudstones recovered during the San Andreas Fault Observatory at Depth (SAFOD) drilling in California, USA. Samples were typically collected as subcores or from drillcore fragments. Helium concentration and isotope ratios were measured 4-6 times on each sample, and indicate a bulk {sup 4}He diffusion coefficient of 3.5 {+-} 1.3 x 10{sup -8} cm{sup 2}s{sup -1} at 21 C, compared to previously published diffusion coefficients of 1.2 x 10{sup -18} cm{sup 2}s{sup -1} (21 C) to 3.0 x 10{sup -15} cm{sup 2}s{sup -1} (150 C) in the sands and clays. Correcting the diffusion coefficient of {sup 4}He{sub water} for matrix porosity ({approx}3%) and tortuosity ({approx}6-13) produces effective diffusion coefficients of 1 x 10{sup -8} cm{sup 2}s{sup -1} (21 C) and 1 x 10{sup -7} (120 C), effectively isolating pore fluid {sup 4}He from the {sup 4}He contained in the rock matrix. Model calculations indicate that <6% of helium initially dissolved in pore fluids was lost during the sampling process. Complete and quantitative extraction of the pore fluids provide minimum in situ porosity values for sandstones 2.8 {+-} 0.4% (SD, n=4) and mudstones 3.1 {+-} 0.8% (SD, n=4).

  17. Trapping of helium in nano-bubbles in euxenite: Positive identification and implications

    NASA Astrophysics Data System (ADS)

    Seydoux-Guillaume, Anne-Magali; David, Marie-Laure; Alix, Kevin; Datas, Lucien; Bingen, Bernard

    2016-08-01

    The (Y,REE,U,Th)-(Nb,Ta,Ti) oxides, like euxenite, fergusonite, pyrochlore, zirconolite, are known to contain nanometric spherical cavities or bubbles, interpreted to contain radiogenic helium. In-situ analyses by Scanning Transmission Electron Microscopy (STEM) coupled with Electron Energy Loss Spectroscopy (EELS) inside nano-bubbles from an euxenite crystal, sampled in its host c. 920 Ma old pegmatite in Norway, deliver, for the first time, a positive identification of helium and an estimation of helium pressure in such bubbles. The chemically unaltered euxenite crystal proves amorphous and homogeneously speckled with bubbles ranging from 5 to 68 nm in diameter, around a log-normal distribution centered at 19 nm. The euxenite contains 9.87 wt% UO2 and 3.15 wt% ThO2. It accumulated a theoretical alpha-decay dose of 3.46 ×1020 α / g (i.e. 170 He/nm3), at a dose rate of 11 926 α / g / s. This corresponds to production of 0.23 wt% He. The density of helium inside the bubbles, estimated from EELS data, ranges from 2 to 45 He/nm3, leading to a pressure of 8 to 500 MPa. The proportion of produced helium trapped in bubbles is about 10%. Helium bubbles clearly influence helium diffusion. They may contribute to the swelling of euxenite during amorphization and to the fracturing of the host rock. Our results suggest that dose, dose rate and structural state seem to be important parameters for the nucleation, growth and coalescence of helium bubbles but also demonstrate the crucial need of experimental studies to be able to develop a predictive model of the long term behavior of materials in response to helium irradiation. Furthermore, chemical alteration of euxenite, here materialized by fluid driven dissolution-precipitation towards silica bearing euxenite, removes the bubbles and mobilizes helium into the rock via cracks and grain boundaries. It is then suggested that helium-rich fluid released from such U-Th rich sources may percolate into surrounding rock units

  18. Charged condensate and helium dwarf stars

    SciTech Connect

    Gabadadze, Gregory; Rosen, Rachel A E-mail: rar339@nyu.edu

    2008-10-15

    White dwarf stars composed of carbon, oxygen and heavier elements are expected to crystallize as they cool down below certain temperatures. Yet, simple arguments suggest that the helium white dwarf cores may not solidify, mostly because of zero-point oscillations of the helium ions that would dissolve the crystalline structure. We argue that the interior of the helium dwarfs may instead form a macroscopic quantum state in which the charged helium-4 nuclei are in a Bose-Einstein condensate, while the relativistic electrons form a neutralizing degenerate Fermi liquid. We discuss the electric charge screening, and the spectrum of this substance, showing that the bosonic long-wavelength fluctuations exhibit a mass gap. Hence, there is a suppression at low temperatures of the boson contribution to the specific heat-the latter being dominated by the specific heat of the electrons near the Fermi surface. This state of matter may have observational signatures.

  19. Helium Find Thaws the Cold Fusion Trail.

    ERIC Educational Resources Information Center

    Pennisi, E.

    1991-01-01

    Reported is a study of cold fusion in which trace amounts of helium, possible evidence of an actual fusion reaction, were found. Research methodology is detailed. The controversy over the validity of experimental results with cold fusion are reviewed. (CW)

  20. Development of charcoal sorbents for helium cryopumping

    SciTech Connect

    Sedgley, D.W.; Tobin, A.G.

    1984-01-01

    Testing of the cryogenically cooled charcoal using fusion-compatible binders for pumping helium has shown promising results. The program demonstrated comparable or improved performance with these binders compared to the charcoal (type and size) using an epoxy binder.

  1. Commissioning of a new helium pipeline

    NASA Technical Reports Server (NTRS)

    2000-01-01

    At the commissioning of a new high-pressure helium pipeline at Kennedy Space Center, Ramon Lugo, acting executive director, JPMO , presents a plaque to Center Director Roy Bridges. The pipeline will service launch needs at the new Delta IV Complex 37 at Cape Canaveral Air Force Station. Others at the ceremony were Jerry Jorgensen, pipeline project manager, Space Gateway Support (SGS); Col. Samuel Dick, representative of the 45th Space Wing; David Herst, director, Delta IV Launch Sites; Pierre Dufour, president and CEO, Air Liquide America Corporation; and Michael Butchko, president, SGS. The nine-mile-long buried pipeline will also serve as a backup helium resource for Shuttle launches. Nearly one launch's worth of helium will be available in the pipeline to support a Shuttle pad in an emergency. The line originates at the Helium Facility on KSC and terminates in a meter station at the perimeter of the Delta IV launch pad.

  2. Commissioning of a new helium pipeline

    NASA Technical Reports Server (NTRS)

    2000-01-01

    Jerry Jorgensen welcomes the audience to the commissioning of a new high-pressure helium pipeline at Kennedy Space Center. Jorgensen, with Space Gateway Support (SGS), is the pipeline project manager. To the right is Ramon Lugo, acting executive director, JPMO. Others at the ceremony were Center Director Roy Bridges; Col. Samuel Dick, representative of the 45th Space Wing; David Herst, director, Delta IV Launch Sites; Pierre Dufour, president and CEO, Air Liquide America Corporation; and Michael Butchko, president, SGS. The pipeline will service launch needs at the new Delta IV Complex 37 at Cape Canaveral Air Force Station. The nine-mile-long buried pipeline will also serve as a backup helium resource for Shuttle launches. Nearly one launch's worth of helium will be available in the pipeline to support a Shuttle pad in an emergency. The line originates at the Helium Facility on KSC and terminates in a meter station at the perimeter of the Delta IV launch pad.

  3. Commissioning of a new helium pipeline

    NASA Technical Reports Server (NTRS)

    2000-01-01

    Center Director Roy Bridges addresses the audience at the commissioning of a new high-pressure helium pipeline at Kennedy Space Center that will service launch needs at the new Delta IV Complex 37 at Cape Canaveral Air Force Station. The nine-mile- long buried pipeline will also serve as a backup helium resource for Shuttle launches. Nearly one launch's worth of helium will be available in the pipeline to support a Shuttle pad in an emergency. The line originates at the Helium Facility on KSC and terminates in a meter station at the perimeter of the Delta IV launch pad. Others at the ceremony were Jerry Jorgensen, pipeline project manager, Space Gateway Support (SGS); Col. Samuel Dick, representative of the 45th Space Wing; Ramon Lugo, acting executive director, JPMO; David Herst, director, Delta IV Launch Sites; Pierre Dufour, president and CEO, Air Liquide America Corporation; and Michael Butchko, president, SGS.

  4. Helium and Enhanced Image of the Sun

    NASA Video Gallery

    This video blinks between an image in Helium and an enhanced image. The original image is from AIA on SDO and the enhanced image was created at the LM Solar and Astrophysics Laboratory (LMSAL) by D...

  5. Primary helium heater for propellant pressurization systems

    NASA Technical Reports Server (NTRS)

    Reichmuth, D. M.; Nguyen, T. V.; Pieper, J. L.

    1991-01-01

    The primary helium heater is a unique design that provides direct heating of pressurant gas for large pressure fed propulsion systems. It has been conceptually designed to supply a heated (800-1000 R) pressurization gas to both a liquid oxygen and an RP-1 propellant tank. This pressurization gas is generated within the heater by mixing super critical helium (40-300 R and 3000-1600 psi) with an appropriate amount of combustion products from a 4:1 throttling stoichiometric LO2/LH2 combustor. This simple, low cost and reliable mixer utilizes the large quantity of helium to provide stoichiometric combustor cooling, extend the throttling limits and enhance the combustion stability margin. Preliminary combustion, thermal, and CFD analyses confirm that this low-pressure-drop direct helium heater can provide the constant-temperature pressurant suitable for tank pressurization of both fuel and oxidizer tanks of large pressure fed vehicles.

  6. Antiprotonic helium and CPT invariance

    NASA Astrophysics Data System (ADS)

    Hayano, Ryugo S.; Hori, Masaki; Horváth, Dezso; Widmann, Eberhard

    2007-12-01

    We review recent progress in the laser and microwave spectroscopy of antiprotonic helium atoms (\\barpHe^+ \\equiv \\rme^\\--\\barp - He^{++}) carried out at CERN's Antiproton Decelerator facility (AD). Laser transitions were here induced between Rydberg states (n, ell) and (n ± 1, ell - 1) of \\barpHe^+ (n ~ 40 and ell ≲ n - 1 being the principal and orbital angular momentum quantum numbers of the antiproton orbit). Successive refinements in the experimental techniques improved the fractional precision on the \\barpHe^+ frequencies from 3 parts in 106 to ~1 part in 108. These included a radiofrequency quadrupole decelerator, which reduced the energy of the antiprotons from 5.3 MeV (the energy of the beam emerging from AD) to ~100 keV. This enabled the production of \\barpHe^+ in ultra-low density targets, where collisional effects with other helium atoms are negligible. A continuous wave pulse-amplified dye laser, stabilized against a femtosecond optical frequency comb, was then used to measure the \\barpHe^+ frequencies with ppb-scale precision. This progress in the experimental field was matched by similar advances in computing methods for evaluating the expected transition frequencies in three-body QED calculations. The comparison of experimental (νexp) and theoretical (νth) frequencies for seven transitions in \\barp^4He^+ and five in \\barp^3 He^+ yielded an antiproton-to-electron mass ratio of m_\\bar p/m_{\\rme} = 1836.152\\,674(5) . This agrees with the known proton-to-electron mass ratio at the level of ~2 × 10-9. The experiment also set a limit on any CPT-violating difference between the antiproton and proton charges and masses, (Q_p - |Q_{\\barp}|)/Q_p \\sim (m_p - m_{\\barp})/m_p < 2 \\times 10^{-9} to a 90% confidence level. If on the other hand we assume the validity of the CPT invariance, the m_{\\barp}/m_{\\rme} result can be taken to be equal to mp/me. This can be used as an input to future adjustments of fundamental constants. The hyperfine

  7. Trace organic impurities in gaseous helium

    NASA Technical Reports Server (NTRS)

    Schehl, T. A.

    1973-01-01

    A program to determine trace organic impurities present in helium has been initiated. The impurities were concentrated in a cryogenic trap to permit detection and identification by a gas chromatographic-mass spectrometric technique. Gaseous helium (GHe) exhibited 63 GC flame ionization response peaks. Relative GC peak heights and identifications of 25 major impurities by their mass spectra are given. As an aid to further investigation, identities are proposed for 16 other components, and their mass spectra are given.

  8. Vacuum-ultraviolet laser uses superfluid helium

    NASA Technical Reports Server (NTRS)

    Zmuidzinas, J. S.

    1979-01-01

    Vacuum ultra violet laser in wavelength around 0.800 microns is produced by using optical pumping to increase lifetimes of excited metastable molecules in super fluid helium. In method, super fluid helium is pumped electronically to produce excited HE2, and then pumped by circularly polarized 0.9096 - micron radiation to aline excited HE2 molecular spins. High power ultraviolet radiation has potential applications in molecular reaction studies, power transmission in space, and biomedical research.

  9. Cosmogenic helium in a terrestrial igneous rock

    NASA Technical Reports Server (NTRS)

    Kurz, M. D.

    1986-01-01

    New helium isotopic measurements on samples from the Kula formation of Haleakala volcano of Hawaii are presented that are best explained by an in situ cosmogenic origin for a significant fraction of the He-3. Results from crushing and stepwise heating experiments, and consideration of the exposure age of the sample at the surface and the cosmic ray fluxes strongly support this hypothesis. Although crustal cosmogenic helium has been proposed previously, this represents its first unambiguous identification in a terrestrial sample.

  10. Photoelectron Spectroscopy of Doped Helium Nanodroplets

    SciTech Connect

    Loginov, Evgeniy; Rossi, Dominic; Drabbels, Marcel

    2005-10-14

    The photoionization dynamics of aniline doped helium droplets has been investigated by photoelectron spectroscopy. The photoelectron spectra resemble closely that of gas phase aniline, except for a droplet-size-dependent shift. This shift is caused by lowering of the ionization threshold upon solvation and can be readily estimated. The individual peaks in the photoelectron spectrum are broadened towards lower kinetic energy which is attributed to the relaxation of the photoelectrons as they pass through the helium droplet.

  11. Superfluid helium on orbit transfer (SHOOT)

    NASA Technical Reports Server (NTRS)

    Dipirro, Michael J.

    1987-01-01

    A number of space flight experiments and entire facilities require superfluid helium as a coolant. Among these are the Space Infrared Telescope Facility (SIRTF), the Large Deployable Reflector (LDR), the Advanced X-ray Astrophysics Facility (AXAF), the Particle Astrophysics Magnet Facility (PAMF or Astromag), and perhaps even a future Hubble Space Telescope (HST) instrument. Because these systems are required to have long operational lifetimes, a means to replenish the liquid helium, which is exhausted in the cooling process, is required. The most efficient method of replenishment is to refill the helium dewars on orbit with superfluid helium (liquid helium below 2.17 Kelvin). To develop and prove the technology required for this liquid helium refill, a program of ground and flight testing was begun. The flight demonstration is baselined as a two flight program. The first, described in this paper, will prove the concepts involved at both the component and system level. The second flight will demonstrate active astronaut involvement and semi-automated operation. The current target date for the first launch is early 1991.

  12. Equation of state of metallic helium

    SciTech Connect

    Shvets, V. T.

    2013-01-15

    The effective ion-ion interaction, free energy, pressure, and electric resistance of metallic liquid helium have been calculated in wide density and temperature ranges using perturbation theory in the electron-ion interaction potential. In the case of conduction electrons, the exchange interaction has been taken into account in the random-phase approximation and correlations have been taken into account in the local-field approximation. The solid-sphere model has been used for the nuclear subsystem. The diameter of these spheres is the only parameter of this theory. The diameter and density of the system at which the transition of helium from the singly ionized to doubly ionized state occurs have been estimated by analyzing the pair effective interaction between helium atoms. The case of doubly ionized helium atoms has been considered. Terms up to the third order of perturbation theory have been taken into account in the numerical calculations. The contribution of the third-order term is significant in all cases. The electric resistance and its temperature dependence for metallic helium are characteristic of simple divalent metals in the liquid state. The thermodynamic parameters-temperature and pressure densities-are within the ranges characteristic of the central regions of giant planets. This makes it possible to assume the existence of helium in the metallic state within the solar system.

  13. High efficiency pump for space helium transfer

    NASA Technical Reports Server (NTRS)

    Hasenbein, Robert; Izenson, Michael G.; Swift, Walter L.; Sixsmith, Herbert

    1991-01-01

    A centrifugal pump was developed for the efficient and reliable transfer of liquid helium in space. The pump can be used to refill cryostats on orbiting satellites which use liquid helium for refrigeration at extremely low temperatures. The pump meets the head and flow requirements of on-orbit helium transfer: a flow rate of 800 L/hr at a head of 128 J/kg. The overall pump efficiency at the design point is 0.45. The design head and flow requirements are met with zero net positive suction head, which is the condition in an orbiting helium supply Dewar. The mass transfer efficiency calculated for a space transfer operation is 0.99. Steel ball bearings are used with gas fiber-reinforced teflon retainers to provide solid lubrication. These bearings have demonstrated the longest life in liquid helium endurance tests under simulated pumping conditions. Technology developed in the project also has application for liquid helium circulation in terrestrial facilities and for transfer of cryogenic rocket propellants in space.

  14. The role of helium gas in medicine

    PubMed Central

    2013-01-01

    The noble gas helium has many applications owing to its distinct physical and chemical characteristics, namely: its low density, low solubility, and high thermal conductivity. Chiefly, the abundance of studies in medicine relating to helium are concentrated in its possibility of being used as an adjunct therapy in a number of respiratory ailments such as asthma exacerbation, COPD, ARDS, croup, and bronchiolitis. Helium gas, once believed to be biologically inert, has been recently shown to be beneficial in protecting the myocardium from ischemia by various mechanisms. Though neuroprotection of brain tissue has been documented, the mechanism by which it does so has yet to be made clear. Surgeons are exploring using helium instead of carbon dioxide to insufflate the abdomen of patients undergoing laparoscopic abdominal procedures due to its superiority in preventing respiratory acidosis in patients with comorbid conditions that cause carbon dioxide retention. Newly discovered applications in Pulmonary MRI radiology and imaging of organs in very fine detail using Helium Ion Microscopy has opened exciting new possibilities for the use of helium gas in technologically advanced fields of medicine. PMID:23916029

  15. Advanced helium magnetometer for space applications

    NASA Technical Reports Server (NTRS)

    Slocum, Robert E.

    1987-01-01

    The goal of this effort was demonstration of the concepts for an advanced helium magnetometer which meets the demands of future NASA earth orbiting, interplanetary, solar, and interstellar missions. The technical effort focused on optical pumping of helium with tunable solid state lasers. We were able to demonstrate the concept of a laser pumped helium magnetometer with improved accuracy, low power, and sensitivity of the order of 1 pT. A number of technical approaches were investigated for building a solid state laser tunable to the helium absorption line at 1083 nm. The laser selected was an Nd-doped LNA crystal pumped by a diode laser. Two laboratory versions of the lanthanum neodymium hexa-aluminate (LNA) laser were fabricated and used to conduct optical pumping experiments in helium and demonstrate laser pumped magnetometer concepts for both the low field vector mode and the scalar mode of operation. A digital resonance spectrometer was designed and built in order to evaluate the helium resonance signals and observe scalar magnetometer operation. The results indicate that the laser pumped sensor in the VHM mode is 45 times more sensitive than a lamp pumped sensor for identical system noise levels. A study was made of typical laser pumped resonance signals in the conventional magnetic resonance mode. The laser pumped sensor was operated as a scalar magnetometer, and it is concluded that magnetometers with 1 pT sensitivity can be achieved with the use of laser pumping and stable laser pump sources.

  16. Sonic helium detectors in the Fermilab Tevatron

    SciTech Connect

    Bossert, R.J.; /Fermilab

    2006-01-01

    In the Fermilab Tevatron cryogenic system there are many remotely located low-pressure plate relief valves that must vent large volumes of cold helium gas when magnet quenches occur. These valves can occasionally stick open or not reseat completely, resulting in a large helium loss. As such, the need exists for a detector to monitor the relief valve's discharge area for the presence of helium. Due to the quantity needed, cost is an important factor. A unit has been developed and built for this purpose that is quite inexpensive. Its operating principle is based on the speed of sound, where two closely matched tubes operate at their acoustic resonant frequency. When helium is introduced into one of these tubes, the resulting difference in acoustic time of flight is used to trigger an alarm. At present, there are 39 of these units installed and operating in the Tevatron. They have detected many minor and major helium leaks, and have also been found useful in detecting a rise in the helium background in the enclosed refrigerator buildings. This paper covers the construction, usage and operational experience gained with these units over the last several years.

  17. Sonic Helium Detectors in the Fermilab Tevatron

    NASA Astrophysics Data System (ADS)

    Bossert, R. J.

    2006-04-01

    In the Fermilab Tevatron cryogenic system there are many remotely located low-pressure plate relief valves that must vent large volumes of cold helium gas when magnet quenches occur. These valves can occasionally stick open or not reseat completely, resulting in a large helium loss. As such, the need exists for a detector to monitor the relief valve's discharge area for the presence of helium. Due to the quantity needed, cost is an important factor. A unit has been developed and built for this purpose that is quite inexpensive. Its operating principle is based on the speed of sound, where two closely matched tubes operate at their acoustic resonant frequency. When helium is introduced into one of these tubes, the resulting difference in acoustic time of flight is used to trigger an alarm. At present, there are 39 of these units installed and operating in the Tevatron. They have detected many minor and major helium leaks, and have also been found useful in detecting a rise in the helium background in the enclosed refrigerator buildings. This paper covers the construction, usage and operational experience gained with these units over the last several years.

  18. Application of gas chromatographic method in simultaneous measurements of helium, argon and neon concentration in groundwaters

    NASA Astrophysics Data System (ADS)

    Najman, J.; Bielewski, J.; Sliwka, I.

    2012-04-01

    Helium concentration in groundwater is a fine indicator in water dating in a range from a hundred to tens of thousands of years. Gas chromatography (GC) measurements of helium can be used as an alternative to mass spectrometry (MS) determinations of 4He for groundwater dating [1]. Argon and neon concentrations mainly serve for determining the temperature of recharge and the air excess which is needed to correct measured values of helium concentration [2] . A chromatographic measurement system of helium, argon and neon concentration in groundwater is presented [3]. Water samples are taken from groundwater with a precise procedure without contamination with air in a special stainless steel vessels of volume equal to 2900 cm3. Helium is extracted from water samples using the head-space method. After enrichment by cryotrap method helium is analyzed in the gas chromatograph equipped with the thermal conductivity detector (TCD) with detection limit of about 2.8 ng He. The helium limit of detection of presented method is 1,2·10-8 cm3STP/gH2O [4]. We are currently working on adapting the method of cryogenic enrichment of helium concentration for simultaneous measurements of the concentration of helium, argon and neon using single sample of groundwater. Neon will be measured with the thermal conductivity detector and capillary column filled with molecular sieve 5A. Argon will be analyzed also with the thermal conductivity detector and packed column filled with molecular sieve 5A. This work was supported by grant No. N N525 3488 38 from the polish National Science Centre. [1] A. Zuber, W. Ciężkowski, K. Różański (red.), Tracer methods in hydrogeological studies - a methodological guide. Wroclaw University of Technology Publishing House, Wroclaw, 2007 (in polish). [2] P. Mochalski, Chromatographic method for the determination of Ar, Ne and N2 in water, Ph.D. thesis, Institute of Nuclear Physics Polish Academy of Sciences in Krakow, 2003 (in polish). [3] A. Żurek, P

  19. Pulsating Helium Atmosphere White Dwarfs

    NASA Astrophysics Data System (ADS)

    Provencal, Judith; Montgomery, Michael H.; Bischoff-Kim, Agnes; Shipman, Harry; Nitta, Atsuko; Whole Earth Telescope Collaboration

    2015-08-01

    The overwhelming majority of all stars currently on the main sequence as well as those from earlier generations will or have ended their stellar lives as white dwarf stars. White dwarfs are rich forensic laboratories linking the history and future evolution of our Galaxy. Their structure and atmospheric composition provide evidence of how the progenitors lived, how they evolved, and how they died. This information reveals details of processes governing the behavior of contemporary main sequence stars. Combined with their distribution in luminosity/temperature, white dwarfs strongly constrain models of galactic and cosmological evolution.GD358 is among the brightest (mv =13.7) and best studied of the pulsating white dwarfs. This helium atmoshere pulsator (DBV) has an extensive photometric database spanning 30 years, including nine multisite Whole Earth Telescope campaigns. GD358 exhibits a range of behaviors, from drastic changes in excited pulsation modes to variable multiplet splittings. We use GD358 as a template for an examination of the DBV class, combining photometric results with recent COS spectroscopy. The results present new questions concerning DB formation and evolution.

  20. Measurement of Helium-3/Helium-4 Ratios in Soil Gas at the 618-11 Burial Ground

    SciTech Connect

    Olsen, Khris B.; Dresel, P Evan; Evans, John C.

    2001-10-31

    Seventy soil gas-sampling points were installed around the perimeter of the 618-11 Burial Ground, approximately 400 feet downgradient of well 699-13-3A, and in four transects downgradient of the burial ground to a maximum distance of 3,100 feet. Soil gas samples were collected and analyzed for helium-3/helium-4 ratios from these 70 points. Helium-3/helium-4 ratios determined from the soil gas sampling points showed significant enrichments, relative to ambient air helium-3 concentrations. The highest concentrations were located along the northern perimeter of the burial ground. Helium-3/helium-4 ratios (normalized to the abundances in ambient air) ranged from 1.0 to 62 around the burial ground. The helium-3/helium-4 ratios from the 4 transect downgradient of the burial ground ranged from 0.988 to 1.68. The helium-3/helium-4 ratios from around the burial ground suggest there is a vadose zone source of tritium along the north side of the burial ground. This vadose zone source is likely the source of tritium in the groundwater. The helium-3/helium-4 ratios also suggest the groundwater plume is traveling east-northeast from the burial ground and the highest groundwater tritium value may be to the north of well 699-13-3A. Finally, there appears to be no immediately upgradient sources of tritium impacting the burial ground since all the upgradient helium-3/helium-4 ratios are approximately 1.0.

  1. Peculiarities of helium bubble formation and helium behavior in vanadium alloys of different chemical composition

    NASA Astrophysics Data System (ADS)

    Staltsov, М. S.; Chernov, I. I.; Kalin, B. A.; Oo, Kyi Zin; Polyansky, A. A.; Staltsova, O. S.; Aung, Kyaw Zaw; Chernov, V. M.; Potapenko, M. M.

    2015-06-01

    The influence of alloying of vanadium by Ti and Fe on helium bubble formation, gaseous swelling and helium release peculiarities is investigated by means of transmission electron microscopy and helium thermal desorption spectrometry (HTDS). The samples were irradiated by 40 keV He+ ions up to a fluence of 5 ṡ 1020 m-2 at 293 and 923 K. It is found that large faceted pores/bubbles are formed in pure vanadium and it has the highest gaseous swelling. Alloying by any used quantity of Ti (from 0.1 up to 10 wt.%) or Fe (from 1 up to 10 wt.%) essentially decreases the helium swelling. The effect of alloying of vanadium by Ti on the bubble sizes and the helium swelling is nonmonotonic. The density of bubbles increases significantly and their sizes and swelling grow monotonically with increasing the Fe content in vanadium. With low-temperature helium implantation, alloying of V by Ti shifts the HTDS peaks to higher temperatures and the temperatures of peaks are decreased with increasing the Fe concentration. A significant portion of the helium releases in a high-temperature area beyond the main peak temperatures in the HTDS spectra. It is assumed that this is caused by formation of helium bubbles on the surfaces of incoherent particles of secondary phases (oxides, nitrides), having high binding energies with these particles.

  2. Helium-neon laser therapy in the treatment of hydroxyapatite orbital implant exposure: A superior option

    PubMed Central

    XU, QI-HUA; ZHAO, CHEN; ZHU, JIAN-GANG; CHEN, MEI-JUAN; LIU, QING-HUAI

    2015-01-01

    The aim of the present study was to evaluate the efficacy of helium-neon laser therapy in the treatment of hydroxyapatite orbital implant exposure and compare the results with those of a combined drugs and surgery regimen. A total of 70 patients with hydroxyapatite orbital implant exposure in 70 eyes were randomly divided into two groups: Helium-neon laser therapy (group A) and drugs plus surgery (group B). Each group contained 35 patients. The healing rates and times of the conjunctival wound were recorded and compared following helium-neon laser treatment or the drugs plus surgery regimen. Changes in the hydroxyapatite orbital implant prior to and following helium-neon laser irradiation were analyzed. A similar animal study was conducted using 24 New Zealand white rabbits, which received orbital implants and were then received drug treatment or helium-neon therapy. In the human experiment, the rates for conjunctival wound healing were 97.14% in group A and 74.29% in group B, with a significant difference between the groups (χ2=5.71, P<0.05). Patients with mild exposure were healed after 7.22±2.11 days of helium-neon laser therapy and 14.33±3.20 days of drugs plus surgery. A statistically significant difference was found between the groups (t=8.97, P<0.05). Patients with moderate to severe exposure were healed after 18.19±2.12 days of helium-neon laser therapy and 31.25±4.21 days of drugs plus surgery. The difference between the groups was statistically significant (t=7.91, P<0.05). Enhanced magnetic resonance imaging showed that the helium-neon laser therapy significantly promoted vascularization of the hydroxyapatite orbital implant. These results, combined with pathological findings in animals, which showed that a helium-neon laser promoted vascularization and had anti-inflammatory effects, suggest that helium-neon laser irradiation is an effective method for treating hydroxyapatite orbital implant exposure, thereby avoiding secondary surgery. PMID

  3. 48 CFR 8.500 - Scope of subpart.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... performance of a Government contract (also see 43 CFR part 3195). ... REQUIRED SOURCES OF SUPPLIES AND SERVICES Acquisition of Helium 8.500 Scope of subpart. This subpart implements the requirements of the Helium Act (50 U.S.C. 167, et seq.) concerning the acquisition of...

  4. 48 CFR 8.500 - Scope of subpart.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... performance of a Government contract (also see 43 CFR part 3195). ... REQUIRED SOURCES OF SUPPLIES AND SERVICES Acquisition of Helium 8.500 Scope of subpart. This subpart implements the requirements of the Helium Act (50 U.S.C. 167, et seq.) concerning the acquisition of...

  5. 48 CFR 8.500 - Scope of subpart.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... performance of a Government contract (also see 43 CFR part 3195). ... REQUIRED SOURCES OF SUPPLIES AND SERVICES Acquisition of Helium 8.500 Scope of subpart. This subpart implements the requirements of the Helium Act (50 U.S.C. 167, et seq.) concerning the acquisition of...

  6. 48 CFR 8.500 - Scope of subpart.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... performance of a Government contract (also see 43 CFR part 3195). ... REQUIRED SOURCES OF SUPPLIES AND SERVICES Acquisition of Helium 8.500 Scope of subpart. This subpart implements the requirements of the Helium Act (50 U.S.C. 167, et seq.) concerning the acquisition of...

  7. 48 CFR 8.500 - Scope of subpart.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... performance of a Government contract (also see 43 CFR part 3195). ... REQUIRED SOURCES OF SUPPLIES AND SERVICES Acquisition of Helium 8.500 Scope of subpart. This subpart implements the requirements of the Helium Act (50 U.S.C. 167, et seq.) concerning the acquisition of...

  8. Detection of Charged Particles in Superfluid Helium

    NASA Astrophysics Data System (ADS)

    Bandler, Simon Richard

    1995-01-01

    At the present time the measurement of the flux of neutrinos from the sun remains a challenging experimental problem. The ideal detector would be able to detect neutrinos at high rate, in real time, with good energy resolution and would have a threshold which is low enough for investigation of the entire solar neutrino spectrum. A new detection scheme using superfluid helium as a target has been proposed which has the potential to meet most of the criteria of the ideal detector. In this scheme a neutrino would be detected when it elastically scatters off an atomic electron in superfluid helium. The electron loses energy via a number of processes eventually leading to the generation of phonons and rotons in the liquid. At low temperatures these excitations propagate ballistically through the superfluid helium. When the excitations reach the free surface some of them are able to evaporate helium atoms. These atoms can be detected by an array of calorimeters suspended above the liquid surface. In this thesis, results are presented for a small -scale prototype of this type of detector. Experiments have been performed using various radioactive sources to generate energy depositions in the liquid. The results reveal details about the processes of generation of rotons and phonons, the propagation of these excitations through the superfluid, the evaporation of helium atoms and the adsorption of helium atoms onto the wafer. Results are also presented on the detection of fluorescent photons generated in the liquid. One source of energy depositions was 241{rm Am} which produces monoenergetic 5.5 MeV alpha particles. It was found that the ratio of the energy deposited in a calorimeter to the energy deposited in liquid helium was 0.084 when alpha's are emitted parallel to the liquid surface, and 0.020 for alpha's emitted perpendicular. The difference is due to the anisotropic distribution of helium excitations generated. A 113{rm Sn} source of 360 keV electrons stopped in

  9. Interaction of infrared light with impurity gels in superfluid helium

    NASA Astrophysics Data System (ADS)

    Izotov, A. N.; Efimov, V. B.

    2011-05-01

    Rapid cooling of an impurity-helium mixture into superfluid helium produces a distinctive soft matter—impurity-helium gel, clusters of which coagulate into nanoparticles. The sizes of the particles and their mutual interaction depend on the nature of the impurity atoms and the impurity-helium coupling. Here we describe the setup of and preliminary results from an experiment to study infrared absorption by a water-helium gel. Comparisons of the infrared absorption spectra of the gel and of water and ice suggests a peculiar interaction among water molecules in a water-helium gel.

  10. D0 Silicon Upgrade: Commissioning Test Results for D-Zero's Helium Refrigerator

    SciTech Connect

    Rucinski, Russ; /Fermilab

    1997-06-30

    The test objectives are: (1) Make liquid helium and measure refrigerator capacity; (2) Measure liquid helium dewar heat leak, transfer line heat leak, and liquid nitrogen consumption rates; (3) Operate all cryogenic transfer lines; (4) Get some running time on all components; (5) Debug mechanical components, instrumentation, DMACs user interface, tune loops, and otherwise shake out any problems; (6) Get some operating time in to get familiar with system behavior; (7) Revise and/or improve operating procedures to actual practice; and (8) Identify areas for future improvement. D-Zero's stand alone helium refrigerator (STAR) liquified helium at a rate of 114 L/hr. This is consistent with other STAR installations. Refrigeration capacity was not measured due to lack of a calibrated heat load. Measured heat leaks were within design values. The helium dewar loss was measured at 2 to 4 watts or 9% per day, the solenoid and VLPC helium transfer lines had a heat leak of about 20 watts each. The liquid nitrogen consumption rates of the mobile purifier, STAR, and LN2 subcooler were measured at 20 gph, 20 to 64 gph, and 3 gph respectively. All cryogenic transfer lines including the solenoid and visible light photon counter (VLPC) transfer lines were cooled to their cryogenic operating temperatures. This included independent cooling of nitrogen shields and liquid helium components. No major problems were observed. The system ran quite well. Many problems were identified and corrected as they came up. Areas for improvement were noted and will be implemented in the future. The instrumentation and control system operated commendably during the test. The commissioning test run was a worthwhile and successful venture.

  11. AM Canum Venaticorum Progenitors with Helium Star Donors and the Resultant Explosions

    NASA Astrophysics Data System (ADS)

    Brooks, Jared; Bildsten, Lars; Marchant, Pablo; Paxton, Bill

    2015-07-01

    We explore the outcome of mass transfer via Roche lobe overflow of {M}{He}≲ 0.51{M}⊙ pure helium burning stars in close binaries with WDs. The evolution is driven by the loss of angular momentum through gravitational wave radiation (GWR), and both stars are modeled using Modules for Experiments in Stellar Astrophysics (MESA). The donors have masses of {M}{He}=0.35,0.4,{and}0.51{M}⊙ and accrete onto WDs of mass MWD from 0.6{M}⊙ to 1.26{M}⊙ . The initial orbital periods (Porb) span 20-80 minutes. For all cases, the accretion rate onto the WD is below the stable helium burning range, leading to accumulation of helium followed by unstable ignition. The mass of the convective core in the donors is small enough so that the WD accretes enough helium-rich matter to undergo a thermonuclear runaway in the helium shell before any carbon-oxygen enriched matter is transferred. The mass of the accumulated helium shell depends on MWD and the accretion rate. We show that for {M}{He}≳ 0.4{M}⊙ and {M}{WD}≳ 0.8{M}⊙ , the first flash is likely vigorous enough to trigger a detonation in the helium layer. These thermonuclear runaways may be observed as either faint and fast Ia SNe or, if the carbon in the core is also detonated, Type Ia SNe. Those that survive the first flash and eject mass will have a temporary increase in orbital separation, but GWR drives the donor back into contact, resuming mass transfer and triggering several subsequent weaker flashes.

  12. BASG thermomechanical pump helium 2 transfer tests

    NASA Technical Reports Server (NTRS)

    Mills, G. L.; Newell, D. A.; Urbach, A. R.

    1990-01-01

    The purpose of the effort described was to perform experiments and calculations related to using a thermomechanical pump in the space-based resupply of the Space Infrared Telescope Facility (SIRTF) with Helium 2. Thermomechanical (fountain effect) pumps have long been suggested as a means for pumping large quantities of Helium 2. The unique properties of Helium 2 have made it useful for cooling space instruments. Several space science missions, including SIRTF, are now being planned which would benefit greatly from on-orbit resupply of Helium 2. A series of experiments were performed to demonstrate that large volumes of Helium 2 can be transferred with a thermomechanical pump at high flow rates and at high efficiency from one dewar to another through valves and lines that are similar to the plumbing arrangement that would be necessary to accomplish such a transfer on-orbit. In addition, temperature, pressure, and flow rate data taken during the tests were used to verify and refine a computer model which was developed.

  13. Dynamic Simulation of a Helium Liquefier

    SciTech Connect

    Maekawa, R.; Ooba, K.; Mito, T.; Nobutoki, M.

    2004-06-23

    Dynamic behavior of a helium liquefier has been studied in detail with a Cryogenic Process REal-time SimulaTor (C-PREST) at the National Institute for Fusion Science (NIFS). The C-PREST is being developed to integrate large-scale helium cryogenic plant design, operation and maintenance for optimum process establishment. As a first step of simulations of cooldown to 4.5 K with the helium liquefier model is conducted, which provides a plant-process validation platform. The helium liquefier consists of seven heat exchangers, a liquid-nitrogen (LN2) precooler, two expansion turbines and a liquid-helium (LHe) reservoir. Process simulations are fulfilled with sequence programs, which were implemented with C-PREST based on an existing liquefier operation. The interactions of a JT valve, a JT-bypass valve and a reservoir-return valve have been dynamically simulated. The paper discusses various aspects of refrigeration process simulation, including its difficulties such as a balance between complexity of the adopted models and CPU time.

  14. Thermal Performance of the XRS Helium Insert

    NASA Technical Reports Server (NTRS)

    Breon, Susan R.; DiPirro, Michael J.; Tuttle, James G.; Shirron, Peter J.; Warner, Brent A.; Boyle, Robert F.; Canavan, Edgar R.

    1999-01-01

    The X-Ray Spectrometer (XRS) is an instrument on the Japanese Astro-E satellite, scheduled for launch early in the year 2000. The XRS Helium Insert comprises a superfluid helium cryostat, an Adiabatic Demagnetization Refrigerator (ADR), and the XRS calorimeters with their cold electronics. The calorimeters are capable of detecting X-rays over the energy range 0.1 to 10 keV with a resolution of 12 eV. The Helium Insert completed its performance and verification testing at Goddard in January 1999. It was shipped to Japan, where it has been integrated with the neon dewar built by Sumitomo Heavy Industries. The Helium Insert was given a challenging lifetime requirement of 2.0 years with a goal of 2.5 years. Based on the results of the thermal performance tests, the predicted on-orbit lifetime is 2.6 years with a margin of 30%. This is the result of both higher efficiency in the ADR cycle and the low temperature top-off, more than compensating for an increase in the parasitic heat load. This paper presents a summary of the key design features and the results of the thermal testing of the XRS Helium Insert.

  15. Transparent Helium in Stripped Envelope Supernovae

    NASA Astrophysics Data System (ADS)

    Piro, Anthony L.; Morozova, Viktoriya S.

    2014-09-01

    Using simple arguments based on photometric light curves and velocity evolution, we propose that some stripped envelope supernovae (SNe) show signs that a significant fraction of their helium is effectively transparent. The main pieces of evidence are the relatively low velocities with little velocity evolution, as are expected deep inside an exploding star, along with temperatures that are too low to ionize helium. This means that the helium should not contribute to the shaping of the main SN light curve, and thus the total helium mass may be difficult to measure from simple light curve modeling. Conversely, such modeling may be more useful for constraining the mass of the carbon/oxygen core of the SN progenitor. Other stripped envelope SNe show higher velocities and larger velocity gradients, which require an additional opacity source (perhaps the mixing of heavier elements or radioactive nickel) to prevent the helium from being transparent. We discuss ways in which similar analysis can provide insights into the differences and similarities between SNe Ib and Ic, which will lead to a better understanding of their respective formation mechanisms.

  16. Torsional Oscillator Studies on Solid Helium

    NASA Astrophysics Data System (ADS)

    Kim, Duk Y.; Chan, Moses H. W.

    2014-03-01

    In 2004, the series of torsional oscillator (TO) experiments by Kim and Chan initiated considerable research activities on the supersolidity of helium. However, recent experiments in rigid torsional oscillators which reduce the effect of stiffening of bulk solid helium at low temepratures showed very small or negligible changes in the resonant period. A new TO experiment of solid helium confined in porous Vycor glass with no bulk solid helium in the sample cell show no evidence of supersolidity. Moreover, we have repeated an earlier experiment on hcp 3He solid, which shows similar low temperature stiffening like hcp 4He. We found that the small drop of the resonant period measured in the hcp 3He samples is comparable to that measured in the hcp 4He samples. These results confirm that the resonant period drops in torsional oscillators are consequence of the shear modulus stiffening effect in solid helium. Remaining issues and open questions on the supersolidity will be discussed. Support for this experiment was provided by NSF Grants No. DMR 1103159.

  17. Commissioning of a new helium pipeline

    NASA Technical Reports Server (NTRS)

    2000-01-01

    At the commissioning of a new high-pressure helium pipeline at Kennedy Space Center, participants cut the lines to helium-filled balloons. From left, they are Center Director Roy Bridges; Michael Butchko, president, SGS; Pierre Dufour, president and CEO, Air Liquide America Corporation; David Herst, director, Delta IV Launch Sites; Pamela Gillespie, executive administrator, office of Congressman Dave Weldon; and Col. Samuel Dick, representative of the 45th Space Wing. The nine-mile-long buried pipeline will service launch needs at the new Delta IV Complex 37 at Cape Canaveral Air Force Station. It will also serve as a backup helium resource for Shuttle launches. Nearly one launch's worth of helium will be available in the pipeline to support a Shuttle pad in an emergency. The line originates at the Helium Facility on KSC and terminates in a meter station at the perimeter of the Delta IV launch pad. Others at the ceremony were Jerry Jorgensen, pipeline project manager, Space Gateway Support (SGS), and Ramon Lugo, acting executive director, JPMO.

  18. Commissioning of a new helium pipeline

    NASA Technical Reports Server (NTRS)

    2000-01-01

    At the commissioning of a new high-pressure helium pipeline at Kennedy Space Center, participants watch as helium-filled balloons take to the sky after their lines were cut. From left, they are Center Director Roy Bridges; Michael Butchko, president, SGS; Pierre Dufour, president and CEO, Air Liquide America Corporation; David Herst, director, Delta IV Launch Sites; Pamela Gillespie, executive administrator, office of Congressman Dave Weldon; and Col. Samuel Dick, representative of the 45th Space Wing. The nine-mile-long buried pipeline will service launch needs at the new Delta IV Complex 37 at Cape Canaveral Air Force Station. It will also serve as a backup helium resource for Shuttle launches. Nearly one launch's worth of helium will be available in the pipeline to support a Shuttle pad in an emergency. The line originates at the Helium Facility on KSC and terminates in a meter station at the perimeter of the Delta IV launch pad. Others at the ceremony were Jerry Jorgensen, pipeline project manager, Space Gateway Support (SGS), and Ramon Lugo, acting executive director, JPMO.

  19. TRANSPARENT HELIUM IN STRIPPED ENVELOPE SUPERNOVAE

    SciTech Connect

    Piro, Anthony L.; Morozova, Viktoriya S.

    2014-09-01

    Using simple arguments based on photometric light curves and velocity evolution, we propose that some stripped envelope supernovae (SNe) show signs that a significant fraction of their helium is effectively transparent. The main pieces of evidence are the relatively low velocities with little velocity evolution, as are expected deep inside an exploding star, along with temperatures that are too low to ionize helium. This means that the helium should not contribute to the shaping of the main SN light curve, and thus the total helium mass may be difficult to measure from simple light curve modeling. Conversely, such modeling may be more useful for constraining the mass of the carbon/oxygen core of the SN progenitor. Other stripped envelope SNe show higher velocities and larger velocity gradients, which require an additional opacity source (perhaps the mixing of heavier elements or radioactive nickel) to prevent the helium from being transparent. We discuss ways in which similar analysis can provide insights into the differences and similarities between SNe Ib and Ic, which will lead to a better understanding of their respective formation mechanisms.

  20. Synergistic effects in hydrogen-helium bubbles.

    PubMed

    Hayward, Erin; Deo, Chaitanya

    2012-07-01

    The detrimental effects of hydrogen and helium on structural materials undergoing irradiation are well documented, if not well understood. There is experimental evidence to suggest that a synergistic effect between the two elements exists, which results in increased damage when both are present. This situation is expected in the next generation of fusion and fission reactors, so a fundamental understanding of these synergistic interactions is needed to predict materials performance. We perform atomistic simulations of hydrogen and helium bubbles in body-centered cubic iron to determine the mechanism behind this effect. We first develop an interatomic potential suitable for describing the interactions between hydrogen and helium. Through analysis of the energetics and structure of these bubbles, we explain the observed synergy as a consequence of bubble growth through helium induced loop punching, aided by the presence of hydrogen, instead of as a direct interaction between hydrogen and helium. The hydrogen benefits from an increased area of free surface on which to bind. PMID:22691382

  1. Subtask 12G1: Effects of dynamically charged helium on swelling and microstructure of vanadium-base alloys

    SciTech Connect

    Chung, H.M.; Nowicki, L.; Gazda, J.; Smith, D.L.

    1995-03-01

    The objective of this work is to determine void structure, distribution, and density changes of several vanadium-base alloys irradiated in the Dynamic Helium Charging Experiment (DHCE). Combined effects of dynamically charged helium and neutron damage on density change, void distribution, and microstructural evolution of V-4Cr-4Ti alloy have been determined after irradiation to 18-31 dpa at 425-600{degrees}C in the DHCE, and the results compared with those from a non-DHCE in which helium generation was negligible. For specimens irradiated to {approx}18-31 dpa at 500-600{degrees}C with a helium generation rate of 0.4-4.2 appm He/dpa, only a few helium bubbles were observed at the interface of grain matrices and some of the Ti(O,N,C) precipitates, and no microvoids or helium bubbles were observed either in grain matrices or near grain boundaries. Under these conditions, dynamically produced helium atoms seem to be trapped in the grain matrix without significant bubble nucleation or growth, and in accordance with this, density changes from DHCE and non-DHCE (negligible helium generation) were similar for comparable fluence and irradiation temperature. Only for specimens irradiated to {approx}31 dpa at 425{degrees}C, when helium was generated at a rate of 0.4-0.8 appm helium/dpa, were diffuse helium bubbles observed in limited regions of grain matrices and near {approx}15% of the grain boundaries in densities significantly lower than those in the extensive coalescences of helium bubbles typical of other alloys irradiated in tritium-trick experiments. Density changes of specimens irradiated at 425{degrees}C in the DHCE were significantly higher than those from non-DHCE irradiation. Microstructural evolution in V-4Cr-4Ti was similar for DHCE and non-DHCE except for helium bubble number density and distribution. As in non-DHCE, the irradiation-induced precipitation of ultrafine Ti{sub 5}Si{sub 3} was observed for DHCE at >500{degrees}C but not at 425{degrees}C.

  2. Dynamics of the Galapagos hotspot from helium isotope geochemistry

    SciTech Connect

    Kurz, M.D.; Geist, D.

    1999-12-01

    The authors have measured the isotopes of He, Sr, Nd and Pb in a number of lava flows from the Galapagos Archipelago; the main goal is to use magmatic helium as a tracer of plume influence in the western volcanoes. Because the Galapagos lava flows are so well preserved, it is also possible to measure surface exposure ages using in situ cosmic-ray-produced {sup 3}He. The exposure ages range from {lt}0.1 to 580 Ka, are consistent with other chronological constrains, and provide the first direct dating of these lava flows. The new age data demonstrate the utility of the technique in this important age range and show that the western Galapagos volcanoes have been erupting distance compositions simultaneously for the last {approximately}10 Ka. The magmatic {sup 3}He/{sup 4}He ratios range from 6.0 to 27 times atmospheric (R{sub a}), with the highest values found on the islands of Isabella (16.8 R{sub a} for Vulcan Sierra Negra) and Fernandina (23 to 27 R{sub a}). Values from Santa Cruz are close to typical mid-ocean ridge basalt values (MORB, of {approximately}9 R{sub 2}) and Pinta has a {sup 3}He/{sup 4}He ratio lower than MORB (6.9 R{sub a}). These data confirm that the plume is centered beneath Fernandina which is the most active volcano in the archipelago and is at the leading edge of plate motion. The data are consistent with previous isotopic studies, confirming extensive contributions from depleted asthenospheric or lithospheric mantle sources, especially to the central islands. The most striking aspect of the helium isotopic data is that the {sup 3}He/{sup 4}He ratios decrease systematically in all directions from Fernandina. This spatial variability is assumed to reflect the contribution of the purest plume component to Fernandina magmatism, and shows that helium is a sensitive indicator of plume influence. The highest {sup 3}He/{sup 4}He ratios are found in volcanoes with lowest Na{sub 2}O(8) and FeO(8), which may relate to source composition as well as degree

  3. Infrared spectroscopy of HOCl embedded in superfluid helium nanodroplets: Probing the dynamical response of the solvent

    NASA Astrophysics Data System (ADS)

    Raston, Paul L.; Kelloway, Donald D.; Jäger, Wolfgang

    2012-07-01

    The rotationally resolved depletion spectrum of hypochlorous acid embedded in helium nanodroplets in the 2.8 μm region is reported. The narrow a-type lines are asymmetrically skewed in the direction of the band origin, and an analysis of their line shapes based on the chirped damped oscillator function introduced by van Staveren and Apkarian [J. Chem. Phys. 133, 054506 (2010)., 10.1063/1.3469816] yields a response time of the helium solvent of 1 ns. The b-type lines are much broader due to the greater number of droplet states available for relaxation of the excited rotational states.

  4. Screw Compressor Characteristics for Helium Refrigeration Systems

    NASA Astrophysics Data System (ADS)

    Ganni, V.; Knudsen, P.; Creel, J.; Arenius, D.; Casagrande, F.; Howell, M.

    2008-03-01

    The oil injected screw compressors have practically replaced all other types of compressors in modern helium refrigeration systems due to their large displacement capacity, minimal vibration, reliability and capability of handling helium's high heat of compression. At the present state of compressor system designs for helium systems, typically two-thirds of the lost input power is due to the compression system. Therefore it is important to understand the isothermal and volumetric efficiencies of these machines to help properly design these compression systems to match the refrigeration process. This presentation summarizes separate tests that have been conducted on Sullair compressors at the Superconducting Super-Collider Laboratory (SSCL) in 1993, Howden compressors at Jefferson Lab (JLab) in 2006 and Howden compressors at the Spallation Neutron Source (SNS) in 2006. This work is part of an ongoing study at JLab to understand the theoretical basis for these efficiencies and their loss mechanisms, as well as to implement practical solutions.

  5. Helium Speech: An Application of Standing Waves

    NASA Astrophysics Data System (ADS)

    Wentworth, Christopher D.

    2011-04-01

    Taking a breath of helium gas and then speaking or singing to the class is a favorite demonstration for an introductory physics course, as it usually elicits appreciative laughter, which serves to energize the class session. Students will usually report that the helium speech "raises the frequency" of the voice. A more accurate description of the phenomenon requires that we distinguish between the frequencies of sound produced by the larynx and the filtering of those frequencies by the vocal tract. We will describe here an experiment done by introductory physics students that uses helium speech as a context for learning about the human vocal system and as an application of the standing sound-wave concept. Modern acoustic analysis software easily obtained by instructors for student use allows data to be obtained and analyzed quickly.

  6. Electron Diffraction of Superfluid Helium Droplets

    PubMed Central

    2014-01-01

    We present experimental results of electron diffraction of superfluid helium droplets and droplets doped with phthalocyanine gallium chloride and discuss the possibility of performing the same experiment with a laser aligned sample. The diffraction profile of pure droplets demonstrates dependence on the nozzle temperature, that is, on the average size of the droplets. Larger clusters demonstrate faster decay with increasing momentum transfer, whereas smaller clusters converge to isolated gas phase molecules at source temperatures of 18 K and higher. Electron diffraction of doped droplets shows similar modified molecular scattering intensity as that of the corresponding gas phase molecules. On the basis of fittings of the scattering profile, the number of remaining helium atoms of the doped droplets is estimated to be on the order of hundreds. This result offers guidance in assessing the possibility of electron diffraction from laser aligned molecules doped in superfluid helium droplets. PMID:24920997

  7. Superfluid helium-4 in one dimensional channel

    NASA Astrophysics Data System (ADS)

    Kim, Duk Y.; Banavar, Samhita; Chan, Moses H. W.; Hayes, John; Sazio, Pier

    2013-03-01

    Superfluidity, as superconductivity, cannot exist in a strict one-dimensional system. However, the experiments employing porous media showed that superfluid helium can flow through the pores of nanometer size. Here we report a study of the flow of liquid helium through a single hollow glass fiber of 4 cm in length with an open id of 150 nm between 1.6 and 2.3 K. We found the superfluid transition temperature was suppressed in the hollow cylinder and that there is no flow above the transition. Critical velocity at temperature below the transition temperature was determined. Our results bear some similarity to that found by Savard et. al. studying the flow of helium through a nanohole in a silicon nitrite membrane. Experimental study at Penn State is supported by NSF Grants No. DMR 1103159.

  8. Thermodynamic properties of hydrogen-helium plasmas

    NASA Technical Reports Server (NTRS)

    Nelson, H. F.

    1971-01-01

    The thermodynamic properties of an atomic hydrogen-helium plasma are calculated and tabulated for temperatures from 10,000 to 100,000 K as a function of the mass fraction ratio of atomic hydrogen. The tabulation is for densities from 10 to the minus 10th power to 10 to the minus 6th power gm/cu cm and for hydrogen mass fraction ratios of 0, 0.333, 0.600, 0.800, and 1.0, which correspond to pure helium, 50 percent hydrogen per unit volume, 75 percent hydrogen per unit volume, 89 percent hydrogen per unit volume, and pure hydrogen plasmas, respectively. From an appended computer program, calculations can be made at other densities and mass fractions. The program output agrees well with previous thermodynamic property calculations for limiting cases of pure hydrogen and pure helium plasmas.

  9. Probing the helium-graphite interaction

    NASA Astrophysics Data System (ADS)

    Cole, Milton W.; Frankl, D. R.; Goodstein, David L.

    1981-04-01

    Two separate lines of investigation have recently converged to produce a highly detailed picture of the behavior of helium atoms physisorbed on graphite basal plane surfaces. Atomic beam scattering experiments on single crystals have yielded accurate values for the binding energies of several states for both 4He and 3He, as well as matrix elements of the largest Fourier component of the periodic part of the interaction potential. From these data, a complete three-dimensional description of the potential has been constructed, and the energy band structure of a helium atom moving in this potential calculated. At the same time, accurate thermodynamic measurements were made on submonolayer helium films adsorbed on Grafoil. The binding energy and low-coverage specific heat deduced from these measurements are in excellent agreement with those calculated from the band structures.

  10. Laser spectroscopic measurement of helium isotope ratios.

    SciTech Connect

    Wang, L.-B.; Mueller, P.; Holt, R. J.; Lu, Z.-T.; O'Connor, T. P.; Sano, Y.; Sturchio, N.; Univ. of Illinois; Univ. of Tokyo; Univ. of Illinois at Chicago

    2003-06-13

    A sensitive laser spectroscopic method has been applied to the quantitative determination of the isotope ratio of helium at the level of {sup 3}He/{sup 4}He = 10{sup -7}--10{sup -5}. The resonant absorption of 1083 nm laser light by the metastable {sup 3}He atoms in a discharge cell was measured with the frequency modulation saturation spectroscopy technique while the abundance of {sup 4}He was measured by a direct absorption technique. The results on three different samples extracted from the atmosphere and commercial helium gas were in good agreement with values obtained with mass spectrometry. The achieved 3{sigma} detection limit of {sup 3}He in helium is 4 x 10{sup -9}. This demonstration required a 200 {mu}L STP sample of He. The sensitivity can be further improved, and the required sample size reduced, by several orders of magnitude with the addition of cavity enhanced spectroscopy.