Recoil Ranges of Products from Reactions of Cu65 with 11-33 Mev He3 Ions
Recoil ranges of products from reactions copper 65 with 11-35 MeV helium 3 ions
HELIUM 3↗
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The ratio of the thermal accommodation coefficients of He4 to He3 as observed and as predicted on the basis of various existing theories
Accommodation coefficients ratio of He 4 to He 3 measured on W and K clean surfaces
Harris, R. E.↗
Interaction of 42 MeV alpha-particles with He3
Differential elastic cross sections of 42 MeV alpha particles scattering from He 3, using optical model with spin-orbit potential
Boschitz, E. T.↗
Observations of homogeneous phase separation in liquid He3-He4 mixtures
The so-called miscibility gap that exists below the critical point in liquid He-3 - H-4 mixtures makes it possible to study binary phase composition, and the ensuing dispersions, in a system possessing an additional order parameter in one of the components. The physical behavior of a superfluid dispersion produced by pressure quenching an He-3 - He-4 mixture into the miscibility gap is described. The description applies both to quenches of homogeneous and phase-separated initial states in various regions of the miscibility gap.
Hoffer, J. K.↗
Statistical mechanics of dilute liquid mixtures of He3 in He4
The Woo-Tan-Massey quantum-mechanical theory of dilute mixtures of He-3 in liquid He-4 is extended to incorporate superfluid flow. Then statistical-mechanical principles are employed to find explicit formulas for thermodyanmic and hydrodynamic properties of mixtures, such as internal energy, free energy, entropy, pressure, chemical potential, and normal-fluid and superfluid densities. This paper is the first in a planned series that applies methods originally developed for pure liquid He-4 to dilute mixtures as a means of establishing a comprehensive theory that includes a theoretical bridge between a microscopic description of the mixtures and a hydrodynamic two-fluid model. Ultimately effects of applied electric and magnetic fields on dilute solutions are also planned to be treated.
Jackson, H. W.↗
Cosmic ray He3 measurements
Cosmic ray 3He/4H3 observations, including a new measurement at approximately 65 MeV/nucleon from ISEE-3, are compared with interstellar propagation and solar modulation models in an effort to understand the origin of cosmic ray He nuclei.
Mewaldt, R. A.↗
The heavy ion compositional signature in 3He-rich solar particle events
A survey of the approx. 1 MeV/nucleon heavy ion abundances in 66 He3-rich solar particle events was performed using the Max-Planck-Institut/University of Maryland and Goddard Space Flight Center instruments on the ISEE-3 spacecraft. The observations were carried out in interplanetary space over the period 1978 October through 1982 June. Earlier observations were confirmed which show an enrichment of heavy ions in HE3-rich events, relative to the average solar energetic particle composition in large particle events. For the survey near 1.5 MeV/nucleon the enrichments compared to large solar particle events are approximately He4:C:O:Ne:Mg:Si:Fe = 0.44:0.66:1.:3.4:3.5:4.1:9.6. Surprising new results emerging from the present broad survey are that the heavy ion enrichment pattern is the same within a factor of approx. 2 for almost all cases, and the degree of heavy ion enrichment is uncorrelated with the He3 enrichment. Overall, the features established appear to be best explained by an acceleration mechanism in which the He3 enrichment process is not responsible for the heavy ion enrichment, but rather the heavy ion enrichment is a measure of the ambient coronal composition at the sites where the He3-rich events occur.
Mason, G. M.↗
The galatic and LMC extreme line supergiants compared: IUE observations of the Henize-Carlson and Zoo star samples of massive supergiants
The Henize-Carlson sample of galactic massive supergiants, and a comparison between the Galactic and LMC samples are discussed. Several of the stars, notably He3-395 and S 127/LMC, have very similar shell characteristics. There appears to be little difference, other than luminosity, between the LMC and Galactic samples. One star, He3-1482, was detected with the Very Large Array at 6 cm. The UV data is combined with IRAS and optical information.
Shore, S. N.↗
Thermal diffusion in a loaded sphere-smooth sphere mixture - A model for super 4 He-HT and super 3 He-HD.
Thermal diffusion in systems He4-HT and He3-HD analyzed by mixture of loaded and smooth spheres as model, discussing inelastic collisions
Mason, E. A.↗
Classical theory of small energy accommodation coefficients - Application to super 3 He and super 4 He on W
Energy accommodation coefficients for He3-W and He4-W, comparing results with classical gas-solid interaction theory
Goodman, F. O.↗
Tritium trick
Large controlled amounts of helium in uniform concentration in thick samples can be obtained through the radioactive decay of dissolved tritium gas to He3. The term, tritium trick, applies to the case when helium, added by this method, is used to simulate (n,alpha) production of helium in simulated hard flux radiation damage studies.
Green, W. V.↗
Solar cycle variations of anomalous He-4 as deduced by studies of cosmic ray He-3
Voyager 1 and 2 observations have been used to derive the energy spectrum of 'anomalous' cosmic-ray (ACR) He using a technique based on the separation of the isotopes of He. Previously reported observations show that the ACR oxygen spectrum underwent a change in shape following the solar magnetic field reversal in 1980; in this paper evidence for a corresponding change in the ACR He spectrum is presented. It is found that the energy spectra of ACR He and oxygen and Galactic-cosmic-ray He-4 and He3 can be reproduced both before and after the field reversal using a simple solar modulation model in which the effects of curvature and gradient drifts are arbitrarily neglected.
Cummings, A. C.↗
Current developments in NASA cryogenic cooler technology
Cooler technologies that are being developed by NASA to meet the varying temperature and cooling power requirements of NASA instruments are described. In addition to providing the desired operating temperature and cooling power by stabilizing temperatures from room temperature down to 0.1 K or less, these coolers will have working lifetimes commensurate with the 10 to 15 year lifetime expected for major future NASA facilities. The types of coolers currently under development are discussed, including radiative coolers, solid cryogen coolers, surface tension confined liquid cryogen coolers, mechanical coolers, liquid helium dewars, He3 adsorption coolers, adiabatic demagnetization refrigerators, and dilution refrigerators.
Castles, Stephen H.↗
Quantitative understanding of the cycles of oxidized and reduced sulfur on Venus
The evolution of the Venus atmosphere is determined by the supply of gases from the interior of the planet and outer space, and by the loss of particles to space over time. In particular, questions pertaining to the initial inventory of water and the current and past rates of outgassing can be addressed by studying the loss rates of H, D, He3 and He4. The photochemistry of the H2SO4 clouds may also have played an important role in regulating the amount of water above the cloud tops, and hence limit the rate of escape of hydrogen from the planet. Thus the problems of evolution and chemistry are intimately related. In our proposal the principal tasks we undertook to advance our understanding of the origin and evolution of water on Venus included: (1) escape of light atoms from Venus and (2) develop a photochemical model of sulfate formation. In the last two years we have made progress on Task 1 regarding how light atoms can escape from the exosphere of Venus with the development of a Monte Carlo program and in Task 2 have developed a thorough update on the SO2 photochemistry that had been previously carried out.
Yung, Yuk L.↗
Helium-3 Mining Aerostats in the Atmospheres of the Outer Planets
Imagine an interplanetary future where: a) d-He3 fusion produces most of Earth s energy needs without radioactivity or carbon emissions; b) Space transportation has been revolutionized by an efficient fusion propulsion system with exhaust velocity up to 0.088 c; c) Space commerce is stimulated by the existence of an interplanetary cargo worth $3-M a kilogram; and d) Unmanned probes travel to the nearest star systems with flight times less than a human lifetime.
VanCleve, Jeffrey E.↗
Use of Apollo 17 Epoch Neutron Spectrum as a Benchmark in Testing LEND Collimated Sensor
The Apollo 17 neutron experiment LPNE provided a unique set of data on production of neutrons in the Lunar soil bombarded by Galactic Cosmic Rays (GCR). It serves as valuable "ground-truth" in the age of orbital remote sensing. We used the neutron data attributed to Apollo 17 epoch as a benchmark for testing the LEND's collimated sensor, as introduced by the geometry of collimator and efficiency of He3 counters. The latter is defined by the size of gas counter and pressure inside it. The intensity and energy spectrum of neutrons escaping the lunar surface are dependent on incident flux of Galactic Cosmic Rays (GCR) whose variability is associated with Solar Cycle and its peculiarities. We obtain first the share of neutrons entering through the field of view of collimator as a fraction of the total neutron flux by using the angular distribution of neutron exiting the Moon described by our Monte Carlo code. We computed next the count rate of the 3He sensor by using the neutron energy spectrum from McKinney et al. [JGR, 2006] and by consider geometry and gas pressure of the LEND sensor. Finally the neutron count rate obtained for the Apollo 17 epoch characterized by intermediate solar activity was adjusted to the LRO epoch characterized by low solar activity. It has been done by taking into account solar modulation potential, which affects the GCR flux, and in turn changes the neutron albedo flux.
Chin, Gordon↗
Multiplexing of Hot-Electron Nanobolometers Using Microwave SQUIDs
We have obtained the first data on the multiplexed operation of titanium hot-electron bolometers (HEB). Because of their low thermal conductance and small electron heat capacity nanobolometers are particularly interesting as sensors for far-infrared spectroscopy and mid- and near-IR calorimetry. However, the short time constant of these devices (approximately microseconds at 300-400 mK) makes time domain or audio-frequency domain multiplexing impractical. The Microwave SQUID (MSQUID) approach pursued in this work uses dc SQUIDs coupled to X-band microresonators which are, in turn, coupled to a transmission line. We used a 4-element array of Ti HEBs operated at 415 mK in a He3 dewar with an optical fiber access. The microwave signal exhibited 10-MHz wide resonances at individual MSQUD frequencies between 9 GHz and 10 GHz. The resonance depth is modulated by the current through the bolometer via a change of the SQUID flux state. The transmitted signal was amplified by a cryogenic amplifier and downconverted to baseband using an IQ mixer. A 1-dB per ??/2 responsivity was sufficient for keeping the system noise at the level of ~ 2 pA/Hz1/2. This is more than an order of magnitude smaller than phonon noise in the HEB. The devices were able to detect single near- IR photons (1550 nm) with a time constant of 3.5 ?s. Follow-on work will scale the array to larger size and will address the microwave frequency signal generation and processing using a digital transceiver.
microwave readout↗