The tensor analyzing power T20 in the dd → 3Hen and dd → 3Hp reactions at the energies 140, 200 and 270 MeV at zero angle

International Nuclear Information System (INIS)

Ladygin, V.P.; ); Uesaka, T.; Saito, T.

2006-01-01

The data on the tensor analyzing power T 20 in the dd → 3 Hen and dd → 3 Hp reactions at 140, 200 and 270 MeV of the deuteron kinetic energy and at zero angle obtained at RIKEN Accelerator Research Facility are presented. The observed positive sign of T 20 clearly demonstrates the sensitivity to the D/S wave ratios in the 3 He and 3 H in the energy domain of the measurements. The T 20 data for the 3 Hen and 3 Hp channels are in agreement within experimental accuracy [ru

Validity of apparent diffusion coefficient hyperpolarized 3He-MRI using MSCT and pulmonary function tests as references

DEFF Research Database (Denmark)

Diaz, Sandra; Casselbrant, Ingrid; Piitulainen, Eeva

2008-01-01

PURPOSE: To compare apparent diffusion coefficient (ADC) measurements from hyperpolarized (HP) helium ((3)He)-magnetic resonance imaging (MRI) with quantitative data from multislice Computed Tomography (CT) (MSCT) of the whole lungs and pulmonary function tests (PFT). MATERIALS AND METHODS: Twenty......-seven subjects, 22 with established emphysema and 5 with preclinical emphysema defined by PFT criteria, were examined with HP (3)He-MRI and MSCT. Mean age was 55 (+/-12) years, 18 female and 9 male. Mean ADC from (3)He-MRI was compared with emphysema index (EI), 15th percentile and mean lung density (MLD) values...... from MSCT. Both mean ADC and MSCT data were compared to PFT, especially percent of predicted diffusing capacity of carbon monoxide (%predicted DLCO), using Pearson's correlation test. RESULTS: Mean ADC and standard deviation values were 0.392+/-0.119 cm(2)/s for the established emphysema group and 0...

X-ray Debye-Waller factor measurements of solid 3He and 4He

International Nuclear Information System (INIS)

Arms, D.A.; Shah, R.S.; Simmons, R.O.

2003-01-01

X-ray synchrotron radiation was used to measure Debye-Waller factors of helium crystals for both 3 He and 4 He in both hcp and fcc phases. To our knowledge, there are no previous measurements for 3 He. The ranges studied for 3 He and 4 He crystals were 11.52-12.82 and 10.95-12.13 cm 3 , respectively, and 11.5-18.2 and 12.0-20.3 K. With small uncertainty, only a Gaussian dependence upon momentum transfer Q was found, and no anisotropy was detected in the hcp phase. Mean square atomic deviations, 2 >, and Lindemann ratios were obtained. Large Lindemann ratios confirm that these solids are highly anharmonic. The 2 > values agree within an average 1% with computations of Draeger and Ceperley from path integral Monte Carlo methods including unusual extrapolations to the thermodynamic limit. Because the path-integral Monte Carlo (PIMC) computations exhibit a T 3 dependence for 2 >, which also depends upon molar volume, an empirical analysis was made of the present data as well as of published x-ray and neutron data on hcp 4 He. The volume dependencies are similar to those found from calorimetry, over a large volume range, and the temperature dependencies show similar systematic variations with molar volume both in x-ray data and PIMC results

Performance of a mass spectrometer for determining low tritium levels from 3He/4He measurements

International Nuclear Information System (INIS)

Lynch, M.C.F.; Kay, D.J.

1981-01-01

The Micromass 3000 mass spectrometer is based on Clarke's 3 He/ 4 He instrument of McMaster University. The principal special features of the MM3000 are: (i) The double collector system, which uses an electron multiplier for the small 3 He + ion beams and a conventional Faraday detector for 4 He + ; (ii) The high sensitivity ion source; and (iii) The low-volume analyser tube employing static vacuum techniques. The sensitivity, resolution and background of the system are designed to permit measurement of 3 He and 4 He levels of the order of 10 -12 cm 3 STP and 10 -6 cm 3 STP, respectively, with a precision of 0.5%, although smaller quantities are detectable. The inherent resolution of the instrument is well in excess of 2000, but a resolution of 600-1000 is normally used for the 3 He + collector as this is sufficient to separate 3 He + from any interfering HD + or H + 3 ions. At this resolution 900 ions per second of 3 He + ions are obtained from 10 -12 cm 3 STP of 3 He. This is the size of 3 He samples obtained from water samples containing tritium at levels around 200 tritium units (1 tritium unit (TU) = IT/10 18 H). At lower tritium levels the 3 He + signal is correspondingly reduced, but the same techniques (described below) allow signals from 1-TU samples (5 ions/s) to be measured with good precision. The limit of detection is reached with quantities of 3 He in the region of 10 -15 cm 3 STP and tritium levels of around 0.1 TU. (author)

NMR and superfluidity of 3He in 3He-4He solutions

International Nuclear Information System (INIS)

Ivanova, K.D.; Mejerovich, A.Eh.

1986-01-01

Two possibilities of determining the superfluid transition temperature for 3 He in a 3 He- 4 He solution by the NMR technique are discussed. One of the methods consists in measuring the spin diffusion coefficient in weak magnetic fields at ultralow temperatures, and the other in measuring the ratio of the spin diffusion coefficient to the spin wave absorption coefficient at not very low temperatures. The transition temperature is estimated on the basis of the available experimental data. The effect of the superfluid transition in a system of 3 He quasiparticles on the propagation of transverse spin waves and longitudinal spin-sound oscillations in 3 He- 4 He solutions is studied. It is shown that there is a range of weak magnetic field intensities restricted from both sides in which the propagation of weakly damped spin-sound waves is possible

Cluster model study of the excited states of /sup 4/He

Energy Technology Data Exchange (ETDEWEB)

Furutani, H. [Osaka Univ., Suita (Japan). Research Center for Nuclear Physics; Ikegami, H.; Muraoka, M. [eds.; Osaka Univ., Suita (Japan). Research Center for Nuclear Physics

1980-01-01

Excited states of /sup 4/He are studied in the energy region E sub(x) = 20 -- 35 MeV within the framework of a (3N + N)-cluster model. (/sup 3/H + p) - (/sup 3/He + n) coupled channel calculation is carried out and results are compared with /sup 3/H(p, p)/sup 3/H, /sup 3/He(n, n)/sup 3/He and /sup 3/H(p, n)/sup 3/He reactions.

The sup(40,44,48)Ca(3He, 3He) and (3He, 4He) reactions at 50 MeV

International Nuclear Information System (INIS)

Griffiths, R.J.; Duggan, F.; Clarke, N.M.

1981-01-01

Measurements have been made of the ( 3 He, 3 He) and ( 3 He, 4 He) reactions on the isotopes of calcium 40 Ca, 44 Ca and 48 Ca at an energy of 50.4 MeV. The results have been analysed with conventional optical potentials and DWBA. The adequacy of the former and inadequacy of the latter for reactions with composite particles is discussed. (author)

Hyperfine Structure Measurements of Antiprotonic $^3$He using Microwave Spectroscopy

CERN Document Server

Friedreich, Susanne

The goal of this project was to measure the hyperfine structure of $\\overline{\\text{p}}^3$He$^+$ using the technique of laser-microwave-laser spectroscopy. Antiprotonic helium ($\\overline{\\text{p}}$He$^+$) is a neutral exotic atom, consisting of a helium nucleus, an electron and an antiproton. The interactions of the angular momenta of its constituents cause a hyperfine splitting ({HFS}) within the energy states of this new atom. The 3\\% of formed antiprotonic helium atoms which remain in a metastable, radiative decay-dominated state have a lifetime of about 1-3~$\\mu$s. This time window is used to do spectroscopic studies. The hyperfine structure of $\\overline{\\text{p}}^4$He$^+$ was already extensively investigated before. From these measurements the spin magnetic moment of the antiproton can be determined. A comparison of the result to the proton magnetic moment provides a test of {CPT} invariance. Due to its higher complexity the new exotic three-body system of $\\overline{\\text{p}}^3$He$^+$ is a cross-check...

Combined He3 cryostats and He3-He4 dilution refrigerators

International Nuclear Information System (INIS)

Kovac, L.; Balla, J.

1974-07-01

A modular set of equipment was designed, which consists of a 4 He Dewar vessel with a very low evaporation rate, having a pumped 4 He bath in which either a 3 He cryostat or a dilution refrigerator within removable inserts can be placed. Any of them can be simply and rapidly connected to the versatile Dewar, auxiliary 4 He-, vacuum; and 3 He- 4 He systems. Two such sets have already been completed and can be used at temperatures from 1.5K to 0.05K for thermodynamic and neutron diffraction measurements. The performance of all inserts was stable and reliable, differences between the cryostats and runs were small - nearly all within the accuracy of temperature determination. The construction of a lot of parts is identical, allowing rapid manufacture. Assembling and repairs are simple, all parts are easily accessible. (K.A.)

Measurement of the polarized neutron---polarized 3He total cross section

International Nuclear Information System (INIS)

Keith, C.D.; Gould, C.R.; Haase, D.G.; Seely, M.L.; Huffman, P.R.; Roberson, N.R.; Tornow, W.; Wilburn, W.S.

1995-01-01

The first measurements of polarized neutron--polarized 3 He scattering in the few MeV energy region are reported. The total cross section difference Δσ T for transversely polarized target and beam has been measured for neutron energies between 1.9 and 7.5 MeV. Comparison is made to predictions of Δσ T using various descriptions of the 4 He continuum. A brute-force polarized target of solid 3 He has been developed for these measurements. The target is 4.3x10 22 atoms/cm 2 thick and is polarized to 38% at 7 Telsa and 12 mK. copyright 1995 American Institute of Physics

Measurement of fast minority /sub 3/He/sup + +/ energy distribution during ICRF heating

Science.gov (United States)

Post, D.E. Jr.; Grisham, L.R.; Medley, S.S.

A method and means for measuring the fast /sub 3/He/sup + +/ distribution during /sub 3/He/sup + +/ minority Ion Cyclotron Resonance Frequency (ICRF) heating is disclosed. The present invention involves the use of 10 to 100 keV beams of neutral helium atoms to neutralize the fast /sub 3/He/sup + +/ ions in a heated plasma by double charge exchange (/sub 3/He/sup + +/ + /sub 4/He/sup 0/ ..-->.. /sub 3/He/sup 0/ + /sub 4/He/sup + +/). The neutralized fast /sub 3/He/sup 0/ atoms then escape from the hot plasma confined by a magnetic field and are detected by conventional neutral particle analyzing means. This technique permits the effectiveness of the coupling of the ion cyclotron waves to the /sub 3/He/sup + +/ minority ions to be accurately measured. The present invention is particularly adapted for use in evaluating the effectiveness of the intermediate coupling between the RF heating and the /sub 3/He/sup + +/ in an energetic toroidal plasma.

3He flow in dilute 3He-4He mixtures at temperatures between 10 and 150 mK

International Nuclear Information System (INIS)

Castelijns, C.A.M.; Kuerten, J.G.M.; de Waele, A.T.A.M.; Gijsman, H.M.

1985-01-01

The mutual friction between 3 He and 4 He II below 150 mK has been studied. Empirical relations for the adiabatic and the nonadiabatic flow properties of 3 He moving through 4 He have been determined using a dilution refrigerator with a single mixing chamber. The validity of the relations is verified by osmotic-pressure measurements and by measuring the properties of a double-mixing-chamber system. It is shown that superleak shunts have a strong effect on the flow characteristics. From the nonadiabatic flow properties an expression is derived for the mutual-friction-force density between 3 He and 4 He II. This has a strong resemblance to the Gorter-Mellink mutual-friction-force density between the normal and the superfluid components in pure 4 He II. It is speculated that the 3 He flow in our systems generates a 4 He vortex tangle, which leads to the observed mutual friction between 3 He and 4 He and also to a strong clamping of the 4 He to the walls

Kinetic energy of He atoms in liquid 4He-3He mixtures

International Nuclear Information System (INIS)

Senesi, R.; Andreani, C.; Fielding, A.L.; Mayers, J.; Stirling, W.G.

2003-01-01

Deep inelastic neutron scattering measurements on liquid 3 He- 4 He mixtures in the normal phase have been performed on the VESUVIO spectrometer at the ISIS pulsed neutron source at exchanged wave vectors of about q≅120.0 A -1 . The neutron Compton profiles J(y) of the mixtures were measured along the T=1.96 K isotherm for 3 He concentrations, x, ranging from 0.1 to 1.0 at saturated vapor pressures. Values of kinetic energies of 3 He and 4 He atoms as a function of x, (x), were extracted from the second moment of J(y). The present determinations of (x) confirm previous experimental findings for both isotopes and, in the case of 3 He, a substantial disagreement with theory is found. In particular (x) for the 3 He atoms is found to be independent of concentration yielding a value 3 (x=0.1)≅12 K, much lower than the value suggested by the most recent theoretical estimates of approximately 19 K

Application of the three-body model to the reactions 6Li(3He,t 3He)3He and 6Li(3He,3He3He)3H

International Nuclear Information System (INIS)

Haftel, M.I.; Allas, R.G.; Beach, L.A.; Bondelid, R.O.; Petersen, E.L.; Slaus, I.; Lambert, J.M.; Treado, P.A.

1977-01-01

Experimental and theoretical cross sections are presented for the 6 Li( 3 He, 3 He 3 He) 3 H and 6 Li( 3 He,t 3 He) 3 He reactions for the symmetric angle pairs 20 0 -20 0 , 28.3 0 -28.3 0 , and 35 0 -35 0 . The theoretical cross sections are calculated in a three-body model where the trions (i.e., mass-3 nuclei) are treated as elementary particles with 6 Li being a 3 He- 3 H bound state. The trion-trion interaction is represented by S wave separable potentials with the breakup cross sections calculated with the tree-body Haftel-Ebenhoeh code. the Coulomb interaction is taken into account by fitting the separable potential parameters to the trion-trion scattering data and is included approximately in the breakup code. The experimental cross sections are compared with both the plane-wave impulse approximation and the three-body model predictions. The plane-wave impulse approximation predicts both the shapes and magnitudes poorly (10 to 20 times experiment). Without Coulomb corrections the three-body model gives good agreement with experiment for the shapes of the spectra with the magnitudes generally being about 40% of experiment for 6 Li( 3 He, 3 He 3 He) 3 H and about 80% for 6 Li( 3 He,t 3 He) 3 He. The Coulomb corrections improve the magnitudes predicted by the three-body model but not the shapes. It is observed that for these reactions S wave separable potentials describe the breakup data much better than they do the two-body trion-trion scattering data. This result should encourage further three-body treatment of these and similar reactions

Tensor analyzing power T20 of the dd →3Hen and dd →3Hp reactions at zero angle for energies 140, 200, and 270 MeV

International Nuclear Information System (INIS)

Ladygin, V. P.; Uesaka, T.; Saito, T.; Hatano, M.; Isupov, A. Yu.; Kato, H.; Ladygina, N. B.; Maeda, Y.; Malakhov, A. I.; Nishikawa, J.; Ohnishi, T.; Okamura, H.; Reznikov, S. G.; Sakai, H.; Sakamoto, N.; Sakoda, S.; Satou, Y.; Sekiguchi, K.; Suda, K.; Tamii, A.

2006-01-01

RIKEN Accelerator Research Facility data on the tensor analyzing power T 20 of the dd → 3 Hen and dd → 3 Hp reactions at zero angle for deuteron kinetic energies of 140, 200, and 270 MeV are reported. The observed positive sign of T 20 clearly demonstrates the sensitivity to the D/S-wave ratio in the 3 He and 3 H wave functions in the energy range of the experiment. Data on T 20 for the 3 Hen channel are in agreement with those for the 3 Hp channel within the experimental errors

Dimerization of 3He in 3He-4He mixture films

International Nuclear Information System (INIS)

Bashkin, E.

1994-01-01

3 He atoms dissolved in superfluid 4 He may form dimers ( 3 He) 2 in two-dimensional geometries. Dimer formation is studied in films of dilute 3 He- 4 He mixture. After designing a schematic 3 He- 3 He interaction potential, the dimer binding energy is calculated for various substrates. It is shown that 3 He impurity states localized near the substrate give rise to the highest magnitudes of the binding energy. (author). 32 refs., 6 figs.,; 1 tab

Specific heat of amorphous 3He films and confined liquid 3He

International Nuclear Information System (INIS)

Golov, A.; Pobell, F.

1995-01-01

We have measured the heat capacities of 3 He films and liquid 3 He in porous Vycor glass at 10 to 600 mK. With increasing the film thickness front 1 to 3 atomic layers , the specific heat evolves gradually from that typical to solid to that of liquid 3 He. At about 2 atomic layers, however, its low-temperature part is nearly temperature-independent; we interpret this as a result of gradual freezing of spins in an amorphous solid 3 He film with decreasing the temperature. The contribution of liquid 3 He in the center of the Vycor pores can be described as the specific heat of bulk liquid 3 He at corresponding pressures in the range 0 to 28 bar. The thickness of amorphous solid on the pore walls increases with external pressure roughly linearly. Preplating the walls with 4 He allows to determine the positions of 3 He atoms contributing to the surface specific heat at 10 to 50 mK. In addition, the contribution from the specific heat of 3 He- 4 He mixing at 100 to 600 mK is discussed as a function of pressure and amount of 4 He

Measurements of the osmotic pressure in liquid mixtures of 3He and 4He near the lambda line and tricritical point

International Nuclear Information System (INIS)

Gearhart, C.A. Jr.

1977-01-01

Values of the concentration susceptibility (par. deltax/par. deltaΔ)/sub T,P/ near the lambda line and tricritical point in liquid mixtures of 3He and 4 He were calculated from measurements of osmotic pressure differences. Measurements were made by inducing a small 3 He mole fraction difference Δx between two chambrs separated by a pressure transducer, and measuring the resulting osmotic pressure difference as a function of temperature

Thermodynamic properties of 3He--4He mixtures near Tlambda

International Nuclear Information System (INIS)

Kakizaki, A.; Satoh, T.

1976-01-01

In order to investigate 3 He impurity effects on the superfluid transition, measurements were made on the thermodynamic quantities, specific heat, thermal expansion coefficients, and pressure dependence of the lambda-transition temperature of three 3 He-- 4 He mixtures and pure 4 He in the neighborhood of the lambda-transition temperature under their saturated vapor pressure. Making use of these measured quantities, it is shown that the so-called Pippard--Buckingham--Fairbank relation holds for 3 He-- 4 He mixtures as well as for pure 4 He, at least in the temperature region of 10 -4 K less than or equal to absolute value (T - T/sub lambda/) less than or equal to 10 -2 K. Based on this, the 3 He impurity effects on the behavior of the specific heat near the lambda-transition are discussed

2H(d,p)3H and 2H(d,n)3He reactions at sub-coulomb energies

International Nuclear Information System (INIS)

Tumino, A.; Spitaleri, C.; Mukhamedzhanov, A. M.; Typel, S.; Spartá, R.; Aliotta, M.; Kroha, V.; Hons, Z.; La Cognata, M.; Lamia, L.; Pizzone, R. G.; Mrazek, J.; Pizzone, R. G.; Rapisarda, G. G.; Romano, S.; Sergi, M. L.

2012-01-01

The 2 H( 3 He,p 3 H) 1 H and 2 H( 3 He,n 3 He) 1 H processes have been measured in quasi free kinematics to investigate for the first time the 2 H(d,p) 3 H and 2 H(d,n) 3 He reactions by means of the Trojan Horse Method. The 3 He+d experiment was performed at 18 MeV, corresponding the a d-d energy range from 1.5 MeV down to 2 keV. This range overlaps with the relevant region for Standard Big Bang Nucleosynthesis as well as with the thermal energies of future fusion reactors and deuterium burning in the Pre Main Sequence phase of stellar evolution. This is the first pioneering experiment in quasi free regime where the charged spectator is detected. Both the energy dependence and the absolute value of the bare nucleus S(E) factors have been extracted for the first time. They deviate by more than 15% from available direct data with new S(0) values of 57.4±1.8 MeVb for 3 H+p and 60.1±1.9 MeVb for 3 He+n. None of the existing fitting curves is able to provide the correct slope of the new data in the full range, thus calling for a revision of the theoretical description. This has consequences in the calculation of the reaction rates with more than a 25% increase at the temperatures of future fusion reactors.

Photodisintegration of 3H and 3He

International Nuclear Information System (INIS)

Faul, D.D.

1980-09-01

The photoneutron cross sections for 3 H and 3 He have been measured from threshold to approx. 25 MeV with monoenergetic photons from the annihilation in flight of fast positrons at the LLL Electron-Positron Linear Accelerator facility. These reactions include the two-body breakup of 3 H and the three-body breakup of both 3 H and 3 He; these measurements for 3 H are the first to span the energy region across the peaks of the cross sections. An efficient BF 3 -tube-and-paraffin neutron detector and high-pressure gaseous samples of several moles each (the activity of the 3 H sample was approx. 200,000 Ci) were employed in these measurements. Measurements on 16 O and 2 H also were performed to verify the absolute cross-section scale. The results, when compared with each other and with results for the two-body breakup cross section for 3 He from the literature, show that the two-body breakup cross sections for 3 H and 3 He have nearly the same shape, but the one for 3 He lies lower in magnitude; the three-body breakup cross section for 3 He lies higher in magnitude and is broader in the peak region and also rises less sharply from threshold than that for 3 H; and these measured differences between the cross sections for the breakup modes largely compensate in their sum, so that the total photon absorption cross sections for 3 H and 3 He are nearly the same in both size and shape at energies near and above their peaks. Theoretical results from the literature disagree with the experimental results to a certain extent over the entire photon-energy region for which the photoneutron cross sections were measured. 50 figures, 7 tables

Inclusive measurements of pion double charge exchange and inelastic scattering on 3He

International Nuclear Information System (INIS)

Yuly, M.E.

1993-06-01

A measurement was made at the Los Alamos Meson Physics Facility (LAMPF) of the doubly differential cross sections for three inclusive pion reactions on 3 He: π - double charge exchange (DCX), and π + and π - inelastic scattering. The cross sections for DCX were measured at incident energies of 120, 180, 210, and 240 MeV, and at angles of 25, 50, 80, 105, and 130 degrees, while inelastic scattering cross sections were measured at 120, 180, and 240 MeV and scattering angles of 50, 80, 105, and 130 degrees. The final pion energy spectrum was measured from 10 MeV up to the kinematic limit. In the Δ resonance region, where the isospin T = 3/2 channel dominates, the inelastic π - scattering should be almost entirely from the lone neutron in 3 He. The π + inelastic scattering was expected to have significant contributions from both single and double scattering, because the T = 3/2 channel favors π + -p scattering from the two protons in 3 He. The 3 He DCX spectra are similar to those observed for DCX in 4 He. The forward angle double peaks can be understood as a consequence of sequential single charge exchange (SSCX). Calculations using the SSCX model are in rough agreement with the measured shape of the 3 He DCX spectra. The doubly differential cross sections measured for the inelastic scattering reactions exhibit a strong enhancement near the kinematics for free π - -p scattering. The ratios of π + to π - scattering cross sections may indicate multiple scattering, as well as the agreement of the low outgoing energy part of the π + inelastic scattering spectra with the corresponding properly scaled DCX spectra. A distorted-wave impulse-approximation (DWIA) calculation of the quasielastic cross sections has been performed and a comparison made with the measured inelastic cross sections

Bound states of 3He in 3He-4He mixture films

International Nuclear Information System (INIS)

Bashkin, E.; Pavloff, N.; Treiner, J.

1995-01-01

3 He atoms dissolved in superfluid 4 He may form dimers ( 3 He) 2 in two-dimensional (2D) geometries. We study dimer formation in films of dilute 3 He- 4 He mixture. After designing a schematic 3 He- 4 He interaction potential we calculate the dimer binding energy for various substrates. It is shown that 3 He impurity states localized near the substrate give rise to the largest magnitudes of the binding energies

Spin waves at the liquid 3He-4He interface

International Nuclear Information System (INIS)

Heff, A.; Candela, D.; Edwards, D.O.; Kumar, S.

1987-01-01

The properties of various interfaces in helium and, in particular, the interface between liquid 3 He and a solution of 3 He in 4 He, may be studied using spin waves. Assuming no transverse relaxation, the boundary condition for the transverse magnetization contains one complex kinetic coefficient, b. For the normal 3 He to 3 He- 4 He interface, b is related to the 3 He quasi-particle transmission probability antiτ, which we estimate from a simple model. A calculation of the spin wave absorption spectrum for a typical geometry shows that b and antiτ may be measured by NMR. Neither b nor antiτ is greatly affected when the pure 3 He enters the A phase, but both are strongly reduced in the B phase

The search for high-energy deuterons in the 3He +3He reaction

International Nuclear Information System (INIS)

Pigeon, R.; Slobodrian, R.J.

1979-01-01

High-energy deuterons have been detected from the 3 He + 3 He reaction with a system sensitive to cross-sections of 0.6 nb sr -1 . Several tests have permitted to evaluate the small contribution of spurious events. The deuterons are kenematically consistent with the reaction 3 He + 3 He→ 2 H + 4 He + e + +ν, but the measured cross-section at 20deg laboratory is too high for a weak-interaction process; (1.3 +- 0.2) nb sr -1 . It might be due to an interaction of intermediate strength causing the decay of pp pairs ( 3 He) into deuterons. Other alternatives and the implications concerning fusion processes and the production of neutrinos in the sun are discussed in the text

d-3He reaction measurements during fast wave minority heating in PLT

International Nuclear Information System (INIS)

Chrien, R.E.; Strachan, J.D.

1983-01-01

Time- and energy-resolved d- 3 He fusion reactions have been measured to infer the energy of the d + or He ++ minority ions heated near their cyclotron frequency by the magnetosonic fast wave. The average energy of the reacting 3 He ions during 3 He minority heating is in the range of 100 to 400 keV, as deduced from the magnitude of the reaction rate, its decay time, and the energy spread of the proton reaction products. The observed reaction rate and its scaling with wave power and electron density and temperature are in qualitative agreement with a radial reaction rate model using the minority distribution predicted from quasilinear velocity space diffusion. Oscillations in the reaction rate are observed concurrent with sawtooth and m = 2 MHD activity in the plasma

Measurement of double polarized asymmetries in quasi-elastic processes ${}^3\\vec{He}(\\vec{e},e' d)$ and ${}^3\\vec{He}(\\vec{e},e' p)$

Energy Technology Data Exchange (ETDEWEB)

Mihovilovic, Miha [Univ. of Ljubljana (Slovenia)

2012-01-01

This thesis is dedicated to a study of a spin-isospin structure of the polarized ³He. First, an introduction to the spin structure of ³He is given, followed by a brief overview of past experiments. The main focus of the thesis is the E05-102 experiment at Jefferson Lab, in which the reactions ${}^3\\vec{He}(\\vec{e},e' d)$ and ${}^3\\vec{He}(\\vec{e},e' p)$ in the quasi-elastic region were studied. The purpose of this experiment was to better understand the effects of the S'- and D-state contributions to the ³He ground-state wave-functions by a precise measurement of beam-target asymmetries A_x and A_z in the range of recoil momenta from 0 to about 300 MeV/c. The experimental equipment utilized in these measurements is described, with special attention devoted to the calibration of the hadron spectrometer, BigBite. Results on the measured asymmetries are presented, together with first attempts at their comparison to the state-of-the art Faddeev calculations. The remaining open problems and challenges for future work are also discussed.

Large-space cluster model calculations for the 3He(3He,2p)4He and 3H(3H,2n)4He reactions

International Nuclear Information System (INIS)

Csoto, Attila; Langanke, Karlheinz

1999-01-01

The 3 He( 3 He, 2p) 4 He and 3 H( 3 H, 2n) 4 He reactions are studied in a microscopic cluster model. We search for resonances in the 3 He+ 3 He and 4 He + p + p channels using methods that treat the two- and three-body resonance asymptotics correctly. Our results show that the existence of a low-energy resonance or virtual state, which could influence the 7 Be and 8 B solar neutrino fluxes, is rather unlikely. Our calculated 3 He( 3 He, 2p) 4 He and 3 H( 3 H, 2n) 4 He cross sections are in a good general agreement with the experimental data

Second sound velocities in superfluid 3He-4He solutions

International Nuclear Information System (INIS)

Dikina, L.S.; Kotenev, G.Ya.; Rudavskij, Eh.Ya.

1978-01-01

The velocities of the second sound in the superfluid He 3 -He 4 solutions were measured by the pulse method in the range of temperatures from 1.3 K to Tsub(lambda) and for He 3 concentrations up to 13%.The results obtained supplemented by those available before give the complete description of the concentration and temperature dependences of the second sound velocity in superfluid He 3 -He 4 solutions. The comprehensive comparison of the experimental data on the velocity of the second sound with the theoretical calculations for the superfluid solutions with arbitrary content of He 3 is performed. The good agreement is found between experiment and the theory. The experimental data obtained are used for determination of the potential, which determines the properties of the superfluid solutions

Thermometry in 3He

International Nuclear Information System (INIS)

Richardson, R.C.

1977-01-01

Some of the methods used in measuring the temperatures of the transitions in 3 He are reviewed. Although noise thermometers, γ-ray anisotropy thermometers and even Pt NMR thermometers are satisfactory for furnishing temperature standards, they are not satisfactory secondary thermometers. The susceptibility of CMN and various 3 He properties make more precise and quicker thermometric indications. (Auth.)

{sup 2}H(d,p){sup 3}H and {sup 2}H(d,n){sup 3}He reactions at sub-coulomb energies

Energy Technology Data Exchange (ETDEWEB)

Tumino, A.; Spitaleri, C.; Mukhamedzhanov, A. M.; Typel, S.; Sparta, R.; Aliotta, M.; Kroha, V.; Hons, Z.; La Cognata, M.; Lamia, L.; Pizzone, R. G.; Mrazek, J.; Pizzone, R. G.; Rapisarda, G. G.; Romano, S.; Sergi, M. L. [Universita degli Studi di Enna Kore, and Laboratori Nazionali del Sud - INFN, via S. Sofia 62, 95123 Catania (Italy); Dipartimento di Fisica e Astronomia, Universita di Catania, and Laboratori Nazionali del Sud - INFN, via S. Sofia 62, 95123 Catania (Italy); Cyclotron Institute Texas A and M University - College Station, Texas (United States); Excellence Cluster Universe - Technische Universitaet Muenchen, Garching, Germany and GSI Helmholtzzentrum fuer Schwerionenforschung GmbH - Theorie Darmstadt (Germany); Dipartimento di Fisica e Astronomia, Universita di Catania, and Laboratori Nazionali del Sud - INFN, via S. Sofia 62, 95123 Catania (Italy); School of Physics and Astronomy - University of Edinburgh, SUPA (United Kingdom); Nuclear Physics Institute of ASCR - Rez near Prague (Czech Republic); Dipartimento di Fisica e Astronomia, Universita di Catania, and Laboratori Nazionali del Sud - INFN, via S. Sofia 62, 95123 Catania (Italy); Nuclear Physics Institute of ASCR - Rez near Prague (Czech Republic); Dipartimento di Fisica e Astronomia, Universita di Catania, and Laboratori Nazionali del Sud - INFN, via S. Sofia 62, 95123 Catania (Italy)

2012-11-20

The {sup 2}H({sup 3}He,p{sup 3}H){sup 1}H and {sup 2}H({sup 3}He,n{sup 3}He){sup 1}H processes have been measured in quasi free kinematics to investigate for the first time the {sup 2}H(d,p){sup 3}H and {sup 2}H(d,n){sup 3}He reactions by means of the Trojan Horse Method. The {sup 3}He+d experiment was performed at 18 MeV, corresponding the a d-d energy range from 1.5 MeV down to 2 keV. This range overlaps with the relevant region for Standard Big Bang Nucleosynthesis as well as with the thermal energies of future fusion reactors and deuterium burning in the Pre Main Sequence phase of stellar evolution. This is the first pioneering experiment in quasi free regime where the charged spectator is detected. Both the energy dependence and the absolute value of the bare nucleus S(E) factors have been extracted for the first time. They deviate by more than 15% from available direct data with new S(0) values of 57.4{+-}1.8 MeVb for {sup 3}H+p and 60.1{+-}1.9 MeVb for {sup 3}He+n. None of the existing fitting curves is able to provide the correct slope of the new data in the full range, thus calling for a revision of the theoretical description. This has consequences in the calculation of the reaction rates with more than a 25% increase at the temperatures of future fusion reactors.

Infrared spectra of 4HeH+, 4HeD+, 3HeH+, and 3HeD+

International Nuclear Information System (INIS)

Crofton, M.W.; Altman, R.S.; Haese, N.N.; Oka, T.

1989-01-01

Isotopic species of the HeH + molecular ion provide an excellent testing ground for studying isotopic dependence of vibration--rotation constants because of the small masses of He and H isotopes. We have observed infrared spectra of the hot band v=2 left-arrow 1 of HeH + and fundamental bands of isotopic species HeD + , 3 HeH + , and 3 HeD + , and obtained the Dunham coefficients Y kl , and the isotopically independent parameters U kl , Δ He kl , and Δ H kl

Superfluid 3He dynamcs in 3He - 4He solutions

International Nuclear Information System (INIS)

Mejerovich, A.Eh.

1984-01-01

The dynamics of a 3 He- 4 He superfluid solution with two condensates ( 3 He and 4 He) is investigated. Despite the fact that the hydrodynamics of the system is a three-velocity one (two superfluid and one normal velocity), all the thermo- and hydrodynamic functions are determined by the value of only a single linear combination of the velocities. 0n the basis of an analogy between a moving solution and a BCS system with coupling with a non-zero momentum, the dependence of the thermodynamic quantities on the velocities and critical velocities can easily be calculated for both homogeneous and inhomogeneous phases of the solution. In a magnetic field the temperature oscillations (analogue of second sound for a superfluid solution) are accompanied by oscillations of the magnetic moment. The velocity and damping of the spin-temperature waves are determined. The orienting action of a current on the inhomogeneous phases of the solution is discussed. It is shown that the energy and size of the vortexes in a superfluid solution are, due to drag effects, oscillating functions of the effective mass of the 3 He quasirartictes (pressure). At a pressure of the order of 10 atm a first order transition should take place in the vortex line which is accompanied by an abrupt change of the circulations of superfluid velocity of 3 He for a fixed circulation of the 4 He velocity

Heat pulses in dilute 3He-4He mixtures

International Nuclear Information System (INIS)

Husson, L.P.J.

1983-01-01

The propagation of heat pulses in dilute 3 He- 4 He mixtures under pressure along a tube, which is long compared to its diameter, is discussed. At high temperatures, where the excitations are in local equilibrium with one another, the propagation of heat pulses in the liquid is determined by the phenomenon of second sound, which is essentially a density wave in the excitation gas. The velocity and attenuation of second sound can be determined from the shape of the transmitted pulse. Measurements on the scattering and absorption of phonons are presented, together with a detailed description of the experimental technique and the electronic equipment. Measurements on the velocity and absorption of second sound are presented. From the results for the velocity of second sound in pure 4 He, values of the phonon and roton parameters are deduced. The velocity data in the mixtures have been used to calculate values of the effective mass of 3 He in superfluid 4 He. The results of these calculations have been compared with values of the effective mass obtained by other authors. The coefficient of second-sound absorption in pure 4 He is computed from theory, making use of the phonon and roton parameters calculated from the second-sound velocity data in pure 4 He. The experimental results on the scattering and absorption of phonons have been analysed. The empirical expressions for the scattering and absorption rates obtained from the diffusive phonon signals were compared with the results of the Baym-Ebner theory, and have also been used to calculate the coefficient of thermal conductivity in dilute 3 He- 4 He mixtures. (Auth.)

Experimental measurements of 3He and 4He mobility in olivine and clinopyroxene at magmatic temperatures

Science.gov (United States)

Trull, T. W.; Kurz, M. D.

1993-03-01

In-vacuo heating of 0.5 -0.7 mm olivine and clinopyroxene grains separated from Hawaiian ultramafic xenoliths leads to complete He loss within hours to days for temperatures of 700-1400°C. Diffusivities calculated from the observed release rates assuming spherical grains and initially homogeneous He distributions define Arrhenius relations with activation energies of 420 ± 20 and 290 ± 40 Kj/mol and log 10D0 of +5.1 ± .7 and +2.1 ± 1.2 cm 2/s in olivine and pyroxene, respectively. Values at 1350°C are 5.3 × 10 -9 cm 2/s in olivine and 10 times faster in pyroxene (4.7 × 10 -8 cm 2/s). These values include small corrections for grain size variations and, in the case of olivine, about 15% prior diffusive He loss. However, an important factor that has not been considered in previous studies of this type, is that the xenolith He resides predominantly within CO 2 rich fluid inclusions. Theoretical description of He loss in such a case demonstrates that the diffusivities calculated using the standard approach actually represent the product of the true volume diffusivity ( D) and the helium solubility, as represented by the distribution coefficient KDv (defined by C crystal/C fluid). Although He solubility in crystals is not well determined, estimates based on the CO 2 concentrations in these samples suggest that it is very low ( KDv of 3 × 10 -4 for pyroxene and 6 × 10 -6 for olivine; which also implies low crystal-melt distribution coefficients of .05 and .001). The resultant corrected diffusion rates are significantly faster than those obtained by the standard approach (~ 10 -4 cm 2/s at 1350°C and are thus higher than basaltic melt values). The most reasonable interpretation of this result is that He release is enhanced by internal grain fractures, including the planar healed cracks along which most fluid inclusions are arrayed. This treatment illustrates the difficulties involved in extrapolating laboratory He release measurements to nature, in particular

Measurements of the osmotic pressure in liquid mixtures of 3He and 4He near the lambda line and tricritical point

International Nuclear Information System (INIS)

Gearhart, C.A. Jr.

1977-06-01

Values of the concentration susceptibility near the lambda line and tricritical point in liquid mixtures of 3 He and 4 He have been calculated from measurements of osmotic pressure differences. Measurements were made by inducing a small 3 He mole fraction difference Δx between two chambers separated by a pressure transducer, and measuring the resulting osmotic pressure difference as a function of temperature. Osmotic equilibrium was established through a Vycor glass superleak, which for 3 He mole fraction x > 0.55 functions not only in the superfluid phase but in portions of the normal fluid region of the phase diagram as well. Measurements were made at four 3 He mole fractions, x = 0.59, x = 0.64, x = 0.68, and x = 0.70. In contrast with determinations from light scattering and vapor pressure measurements, the present measurements show a pronounced peak at the lambda transition for the two values of x less than the tricritical value (x/sub t/ = 0.675). The susceptibilities are consistent with α = 0 both above and below the lambda transition except at x = 0.64, where some combination of α and α' greater than zero seems to be preferred. (The result α = 0 corresponds to a logarithmic divergence.) It is possible that this positive value of α or α' represents the influence of tricritical effects. It should be emphasized that there is considerable ambiguity in our determination of α, with acceptable least-squares fits corresponding to values of α between 0.0 and 0.2 being found at both concentrations, both above and below T/sub lambda/. The results appear to be consistent with the results of other experiments away from the lambda line, and also to be consistent with a simple tricritical scaling relationship

A Precision Measurement of the Neutron Spin Structure Functions Using a Polarized HE-3 Target

International Nuclear Information System (INIS)

Smith, T

2003-01-01

This thesis describes a precision measurement of the neutron spin dependent structure function, g 1 n (x). The measurement was made by the E154 collaboration at SLAC using a longitudinally polarized, 48.3 GeV electron beam, and a 3 He target polarized by spin exchange with optically pumped rubidium. A target polarization as high as 50% was achieved. The elements of the experiment which pertain to the polarized 3 He target will be described in detail in this thesis. To achieve a precision measurement, it has been necessary to minimize the systematic error from the uncertainty in the target parameters. All of the parameters of the target have been carefully measured, and the most important parameters of the target have been measured using multiple techniques. The polarization of the target was measured using nuclear magnetic resonance techniques, and has been calibrated using both proton NMR and by measuring the shift of the Rb Zeeman resonance frequency due to the 3 He polarization. The fraction of events which originated in the 3 He, as measured by the spectrometers, has been determined using a physical model of the target and the spectrometers. It was also measured during the experiment using a variable pressure 3 He reference cell in place of the polarized 3 He target. The spin dependent structure function g 1 n (z) was measured in the Bjorken x range of 0.014 2 of 5 (GeV/c) 2 . One of the primary motivations for this experiment was to test the Bjorken sum rule. Because the experiment had smaller statistical errors and a broader kinematic coverage than previous experiments, the behavior of the spin structure function g 1 n (x) could be studied in detail at low values of the Bjorken scaling variable x. It was found that g 1 n (x) has a strongly divergent behavior at low values of x, calling into question the methods commonly used to extrapolate the value of g 1 n (x) to low x. The precision of the measurement made by the E154 collaboration at SLAC puts a tighter

12C(3He,3He n)11C cross section at 910 MeV

International Nuclear Information System (INIS)

Aslanides, E.; Fassnacht, P.; Dellacasa, G.; Gallio, M.; Tuyn, J.W.N.

1981-01-01

The 12 C( 3 He, 3 He n) 11 C cross section at 910 MeV was measured by using a Ge(Li) gamma spectrometer to determine the disintegration rate and measuring the incident flux by means of a scintillator telescope. Cross sections for the production of 7 Be in C and Al and for the production of 24 Na in Al are then determined using the measured cross section as a monitor

Cosmogenic 3He in detrital gold

Science.gov (United States)

Stuart, Finlay; Yakubovich, Olga; Caracedo, Ana; Nesterenok, Alexander

2017-04-01

Since the measurement of cosmogenic He in an alluvial diamond by McConville and Reynolds (1996) the application of cosmogenic noble gases to individual detrital grains to quantify surface processes has not been vigorously pursued. The likely low rate of diffusion of cosmogenic He in native metals, and their resistance to weathering and disintegration during erosion and transport, makes them a potential record of long-term Earth surface processes. In an effort to assess the extent that detrital refractory metals record the exposure history during transport and storage we have undertaken a reconnaissance study of the He isotope composition in 18 grains (2-200 mg) of native gold, copper, silver, and PtPd, Pt3Fe and OsIr alloys from alluvial placer deposits from around the world. 4He is dominantly the result of U and Th decay within the grains, or decay of 190Pt in the Pt-rich alloys. 3He is measurable in 13 grains, concentrations range up to 2.7E+6 atoms/g. 3He/4He are always in excess of the crustal radiogenic ratio, up to 306 Ra. Although nucleogenic 3He produced by (n,α) reactions on 6Li, and 3He from trapped hydrothermal fluids, are present, the majority of the 3He is cosmogenic in origin. Using newly calculated cosmogenic 3He production rates in heavy metals, and a determination of the effect of implantation based on the stopping distances of spallogenic 3He and 3H, the grains have 3Hecos concentrations that are equivalent to 0.35 to 1.5 Ma exposure at Earth's surface. In a study of detrital gold grains from several sites in Scotland we have found that 10 % have 3He concentrations that are significantly in excess of that generated since the Last Glacial Maximum. These studies demonstrate that, with refinement, cosmogenic 3He in refractory detrital minerals can be used to quantify sediment transport and storage on the 1-10 Ma timescale. P. McConville & J.H. Reynolds (1989). Geochim. Cosmochim. Acta, 53, 2365-75.

Interaction of HP1 and Brg1/Brm with the globular domain of histone H3 is required for HP1-mediated repression.

Directory of Open Access Journals (Sweden)

Marc Lavigne

2009-12-01

Full Text Available The heterochromatin-enriched HP1 proteins play a critical role in regulation of transcription. These proteins contain two related domains known as the chromo- and the chromoshadow-domain. The chromo-domain binds histone H3 tails methylated on lysine 9. However, in vivo and in vitro experiments have shown that the affinity of HP1 proteins to native methylated chromatin is relatively poor and that the opening of chromatin occurring during DNA replication facilitates their binding to nucleosomes. These observations prompted us to investigate whether HP1 proteins have additional histone binding activities, envisioning also affinity for regions potentially occluded by the nucleosome structure. We find that the chromoshadow-domain interacts with histone H3 in a region located partially inside the nucleosomal barrel at the entry/exit point of the nucleosome. Interestingly, this region is also contacted by the catalytic subunits of the human SWI/SNF complex. In vitro, efficient SWI/SNF remodeling requires this contact and is inhibited in the presence of HP1 proteins. The antagonism between SWI/SNF and HP1 proteins is also observed in vivo on a series of interferon-regulated genes. Finally, we show that SWI/SNF activity favors loading of HP1 proteins to chromatin both in vivo and in vitro. Altogether, our data suggest that HP1 chromoshadow-domains can benefit from the opening of nucleosomal structures to bind chromatin and that HP1 proteins use this property to detect and arrest unwanted chromatin remodeling.

X-ray-induced thinning of 3He and 3He/4He mixture films

International Nuclear Information System (INIS)

Penanen, Konstantin; Fukuto, Masafumi; Silvera, Isaac F.; Pershan, Peter

2000-01-01

Films of isotopic mixtures of helium have been studied using x-ray specular reflectivity techniques. In contrast with superfluid 4 He films, x-ray exposure causes a reduction in the thickness of 4 He films above the superfluid transition as well as films of pure 3 He and 3 He/ 4 He mixtures. One proposed model that could account for this effect is a charging model, in which thinning is caused by electrostatic pressure of free charges that accumulate on the helium surface. Unfortunately, this model is not fully consistent with all of the experimental observations. A localized heating model, in which indirect heating of the film causes it to thin would explain the data if there were dissipative film flow in the 3 He/ 4 He mixtures at temperatures where the bulk is superfluid. We argue that various published experimental results suggest such an effect. In this model, film thinning data for dilute 3 He/ 4 He films indicates dissipation that is linear in 3 He content of the film over two orders of magnitude

Mobility of ions trapped on vortex lines in pure 4He and 3He--4He solutions

International Nuclear Information System (INIS)

Ostermeier, R.M.; Glaberson, W.I.

1976-01-01

Measurements have been made of the mobility of positive and negative ions trapped on vortex lines in pure 4 He and dilute 3 He-- 4 He solutions over the temperature range 1.6 greater than T greater than 0.3 K. In pure 4 He below about 0.7 K, several new effects not seen at higher temperatures are observed and are not easily explained with existing theories. Most notable are an enhanced broadening of the ion pulse and a rapid increase in the mobility with decreasing temperature. Measurements of the electric field dependence of the drift velocity in pure 4 He at low temperatures show a limiting velocity for sufficiently large fields. This behavior can be explained using a simple resonance theory. The inverse mobility data for solutions show sharp increases at certain critical temperatures, which are interpreted as being associated with the condensation of 3 He atoms onto the vortex cores. The dependence of the critical temperature on the bulk 3 He concentration is found to be in good agreement with a simple condensation theory. An extension of arguments used in this theory to lower temperatures leads to the picture of a 3 He-rich core growing with decreasing temperature, consistent with our lower temperature experimental data

Third sound resonance studies of 3He-4He mixture films

International Nuclear Information System (INIS)

Heinrichs, R.M.

1985-01-01

Third sound velocity and dissipation measurements were performed on 3 He- 4 He mixture films of 3.6 and 5.3 layers 4 He and up to 3 added layers 3 He in the temperature range 0.05-0.3 K using third sound resonance techniques. The 3 He concentration dependence of the velocity was in excellent agreement with a simple layered film model down to the lowest concentrations studied. At the higher 3 He concentrations, the velocity began to deviate from the model, rising above it. The concentration dependence of the dissipation showed some unique structure with a maximum at 0.3-0.5 layers added 3 He for both 4 He coverages. The third sound velocity in the low concentration mixture films had very little temperature dependence in the range studied. The dissipation, however, had some definite temperature dependent structure that evolved with concentration. This evolution was most pronounced at concentrations near the dissipation maximum and eventually became exponential at the higher coverages. Fitting these exponentials produced estimates of the difference in binding energy for the 3 He states in and on the film. In this higher 3 He concentration regime, a temperature dependence of the velocity was observed that began as a small peak at about 0.15 K and eventually became a step at the highest concentrations studied. The exponential nature of the dissipation became clouded when the velocity evolved into this last behavior

A Precision Measurement of the Neutron Spin Structure Functions Using a Polarized HE-3 Target

Energy Technology Data Exchange (ETDEWEB)

Smith, T

2003-11-05

This thesis describes a precision measurement of the neutron spin dependent structure function, g{sub 1}{sup n}(x). The measurement was made by the E154 collaboration at SLAC using a longitudinally polarized, 48.3 GeV electron beam, and a {sup 3}He target polarized by spin exchange with optically pumped rubidium. A target polarization as high as 50% was achieved. The elements of the experiment which pertain to the polarized {sup 3}He target will be described in detail in this thesis. To achieve a precision measurement, it has been necessary to minimize the systematic error from the uncertainty in the target parameters. All of the parameters of the target have been carefully measured, and the most important parameters of the target have been measured using multiple techniques. The polarization of the target was measured using nuclear magnetic resonance techniques, and has been calibrated using both proton NMR and by measuring the shift of the Rb Zeeman resonance frequency due to the {sup 3}He polarization. The fraction of events which originated in the {sup 3}He, as measured by the spectrometers, has been determined using a physical model of the target and the spectrometers. It was also measured during the experiment using a variable pressure {sup 3}He reference cell in place of the polarized {sup 3}He target. The spin dependent structure function g{sub 1}{sup n}(z) was measured in the Bjorken x range of 0.014 < x < 0.7 with an average Q{sup 2} of 5 (GeV/c){sup 2}. One of the primary motivations for this experiment was to test the Bjorken sum rule. Because the experiment had smaller statistical errors and a broader kinematic coverage than previous experiments, the behavior of the spin structure function g{sub 1}{sup n}(x) could be studied in detail at low values of the Bjorken scaling variable x. It was found that g{sub 1}{sup n}(x) has a strongly divergent behavior at low values of x, calling into question the methods commonly used to extrapolate the value of g

Bare nucleus S(E) factor of the 2H(d,p)3H and 2H(d,n)3He reactions via the Trojan Horse Method

International Nuclear Information System (INIS)

Tumino, A; Spitaleri, C; Kiss, G G; Cognata, M La; Lamia, L; Pizzone, R G; Rapisarda, G G; Romano, S; Sergi, M L; Spartà, R; Mukhamedzhanov, A M; Typel, S; Aliotta, M; Burjan, V; Kroha, V; Hons, Z; Mrazek, J; Piskor, S; Santo, M Gimenez del

2012-01-01

The Trojan Horse Method was applied for the first time to the 2 H(d,p) 3 H and 2 H(d,n) 3 He reactions by measuring the 2 H( 3 He,p 3 H) 1 H and 2 H( 3 He,n 3 He) 1 H processes in quasi free kinematics. The 3 He+d experiment was performed at 18 MeV, corresponding the a d-d energy range from 1.5 MeV down to 2 keV. This range overlaps with the relevant region for Standard Big Bang Nucleosynthesis as well as with the thermal energies of future fusion reactors and deuterium burning in the Pre Main Sequence phase of stellar evolution. This is the first pioneering experiment in quasi free regime where the charged spectator is detected. Both the energy dependence and the absolute value of the bare nucleus S(E) factors have been extracted for the first time. They deviate by more than 15% from available direct data with new S(0) values of 57.4±1.8 MeVb for 3 H+p and 60.1±1.9 MeVb for 3 He+n. None of the existing fitting curves is able to provide the correct slope of the new data in the full range, thus calling for a revision of the theoretical description. This has consequences in the calculation of the reaction rates with more than a 25% increase at the temperatures of future fusion reactors.

Homogeneous nucleation in phase separation of solid 3He-4He mixtures

International Nuclear Information System (INIS)

Poole, M.; Smith, A.; Maidanov, V.A.; Rudavskii, E.Ya.; Grigor'ev, V.N.; Slezov, V.V.; Saunders, J.; Cowan, B.

2003-01-01

NMR and pressure have been measured during phase separation in solid 3 He- 4 He mixtures. Spin echoes were used to observe bounded diffusion and to estimate the diffusion coefficient, size and nuclei concentration in the 3 He-enriched phase. The characteristic phase separation time constant of the mixture was found from pressure measurements. The results argue convincingly for homogeneous nucleation. The surface tension of the nuclei is found independently from NMR and from pressure measurements; the two determinations agree well and yield a surface tension coefficient of 4.9x10 -6 J m -2

The 3H–3He Charge Radii Difference

Directory of Open Access Journals (Sweden)

Myers L. S.

2016-01-01

Full Text Available The upcoming E12-14-009 [1] experiment at Jefferson Lab will determine the ratio of the electric form factors for the A=3 mirror nuclei 3He and 3H. The measurement will use a 1.1 GeV electron beam, a special collimator plate to allow for simultaneous optics measurements, and the low-activity tritium target being prepared for Jefferson Lab. By observing the dependence of the form factor ratio as a function of Q2 over 0.05–0.09 GeV2, the dependence of the radii extraction on the shape of the form factors is minimized. As a result, we anticipate the uncertainty of the extracted charge radii difference to be 0.03 fm, a reduction of 70% from the current measurement. Using precise measurements of the 3He charge radius from isotopic shift or μHe measurements [2–4], we can deduce the absolute 3H charge radius. The results will provide a direct comparison to recent calculations of the charge radii.

Accurate 3He polarimetry using the Rb Zeeman frequency shift due to the Rb-3He spin-exchange collisions

International Nuclear Information System (INIS)

Romalis, M.V.; Cates, G.D.

1998-01-01

We describe a method of 3 He polarimetry relying on the polarization-dependent frequency shift of the Rb Zeeman resonance. Our method is ideally suited for on-line measurements of the 3 He polarization produced by spin-exchange optical pumping. To calibrate the frequency shift we performed an accurate measurement of the imaginary part of the Rb- 3 He spin-exchange cross section in the temperature range typical for spin-exchange optical pumping of 3 He. We also present a detailed study of possible systematic errors in the frequency shift polarimetry. copyright 1998 The American Physical Society

Measurement of coherent π0 photoproduction on 3He and 3H in the resonance region

International Nuclear Information System (INIS)

Bellinghausen, B.; Gassen, H.J.; Reese, E.; Reichelt, T.; Stipp, P.

1984-01-01

Neutral pion photoproduction has been measured on 3 He and 3 H nuclei in the Δ(1,232) resonance region. Resonance averaged cross-sections are presented as a function of momentum transfer and compared to theoretical calculations. (orig.)

Laser - Polarized HE-3 Target Used for a Precision Measurement of the Neutron Spin Structure

Energy Technology Data Exchange (ETDEWEB)

Romalis, M

2003-11-05

This thesis describes a precision measurement of the deep inelastic neutron spin structure function g{sub 1}{sup n}(x). The main motivation for the experiment is a test of the Bjorken sum rule. Because of smaller statistical errors and broader kinematic coverage than in previous experiments, we are able to study in detail the behavior of the spin structure function g{sub 1}{sup n}(x) for low values of the Bjorken scaling variable x. We find that it has a strongly divergent behavior, in contradiction to the naive predictions of the Regge theory. This calls into question the methods commonly used for extrapolation of g{sub 1}{sup n}(x) to x = 0. The difference between the proton and the neutron spin structure functions is less divergent at low x, so a test of the Bjorken sum rule is possible. We confirm the sum rule with an accuracy of 8%. The experiment was performed at SLAC using a 50 GeV polarized electron beam and a polarized {sup 3}He target. In this thesis the polarized target is described in detail. We used the technique of Rb optical pumping and Rb-He spin exchange to polarize the {sup 3}He. Because of a novel mechanical design our target had the smallest dilution ever achieved for a high density gas target. Since this is a precision measurement, particular efforts were made to reduce the systematic errors due to the uncertainty in the target parameters. Most important parameters were measured by more than one method. We implemented novel techniques for measuring the thickness of the glass windows of the target, the {sup 3}He density, and the polarization. In particular, one of the methods for measuring the gas density relied on the broadening of the Rb optical absorption lines by collisions with {sup 3}He atoms. The calibration of this technique resulted in the most precise measurements of the pressure broadening parameters for {sup 3}He as well as several other gases, which are described in an Appendix. The polarization of the {sup 3}He was also measured by

Specific heat of 4He and 3He--4He mixtures at their lambda transition

International Nuclear Information System (INIS)

Gasparini, F.M.; Moldover, M.R.

1975-01-01

We have measured the specific heat near the lambda transition of pure 4 He and of five 3 He-- 4 He mixtures up to a mole fraction of 0.39 3 He in 4 He. Our data for 4 He confirm the results of Ahlers revealing an asymmetry in the exponents above and below T/sub lambda/ when the specific heat is represented by a simple-power-law temperature dependence. Our results for these exponents (α = 0.012 plus-or-minus 0.002 and α' = -0.012 plus-or-minus 0.004) differ somewhat from Ahlers's. Our results can be reconciled with the requirement of scaling (α = α') only by supposing substantial contributions to C/sub p/ are made by singular correction terms to a simple power law. The measured specific heat of the mixtures richest in 3 He appears to be finite, continuous, and cusped at the lambda line. These qualitative features have been termed ''renormalization'' by Fisher. An analysis of our mixture data with a power-law temperature dependence does not yield a fully renormalized exponent, but rather an effective exponent. Derivatives at the lambda line were used to calculate the specific heat along paths of constant pressure and constant relative chemical potential.This specific heat behaves very much like C/sub p/ of pure 4 He, this behavior supporting the idea of universality for the specific-heat exponents. It is also true that the same asymmetry in the branches above and below T/sub lambda/ which is []bserved in pure 4 He is retained in the mixtures. The persistence of the asymmetry of C/subp//sub phi/ as one moves along the lambda line towards increasing 3 He concentration (at the saturated vapor pressure of the mixtures) is analogous to the persistence of the asymmetry of C/subp/ as one moves along the lambda line towards increasing pressure in pure 4 He

(3He,xn), (3He,pxn) and (3He, fission) reactions on 206Pb between 80 and 200MeV

International Nuclear Information System (INIS)

Andre, C.; Gauvin, H.; Le Beyec, Y.; Porile, N.T.

1976-01-01

The reactions induced in 206 Pb by 3 He particles having energies between 80 and 200MeV have been studied. Excitation functions for ( 3 He,xn) with x=3 to 14 and for ( 3 He,pxn) with x=2 to 5 have been obtained. Angular distributions of fission fragments were measured at 100, 125, 150 and 175MeV and total fission cross-sections were deduced from the data. On the basis of these results, analysis is attempted to examine the characteristics of reaction mechanisms. From these results it is concluded that non-compound processes play an important role in the reactions. Two features are characteristic of these processes: large cross-sections for charged particle emission and angular distribution of fission fragments closed to isotropy in the laboratory system. In the energy range 25 to 45MeV/nucleon, a comparison was made between the present results and those from an experimental study of α-particle induced reactions on 206 Pb. Also a comparison was made with an α-nucleus collision model applied to 206 Pb. All the observations strongly suggest a breakup of the projectile 3 He followed by the interactions of the fragments with the target nucleus [fr

Precise measurement of the neutron magnetic form factor from quasielastic 3 rvec He(rvec e,e')

International Nuclear Information System (INIS)

Gao, H.

1997-01-01

Polarized 3 He targets have proven to be a useful tool for studying the electric and magnetic form factors of the neutron, and the spin structure of the neutron. The neutron magnetic form factor at low Q 2 was determined previously at MIT-Bates from the quasielastic 3 rvec He(rvec e, e ' ) process. New experiment was planned at TJNAF to systematically measure the inclusive 3 He quasielastic transverse asymmetry, A T ' , at Q 2 = 0.1 - 0.5 (GeV/c) 2 with high statistical and systematic accuracy. A 2% statistical uncertainty is aimed at all the pro- posed values of Q 2 , and 3% systematic uncertainty for A T ' can be achieved for this experiment. The precise data will constrain theoretical calculations of 3 He quasielastic asymmetry. Furthermore, the neutron magnetic form factor at Q 2 = 0.1 - 0.5 (GeV/c) 2 will be extracted from the measured asymmetries with an overall uncertainty of 2%. Precise measurements of G n M at low Q 2 will resolve the discrepancy among the existing data in the same Q 2 region

Validity of apparent diffusion coefficient hyperpolarized 3He-MRI using MSCT and pulmonary function tests as references

DEFF Research Database (Denmark)

Diaz, Sandra; Casselbrant, Ingrid; Piitulainen, Eeva

2008-01-01

from MSCT. Both mean ADC and MSCT data were compared to PFT, especially percent of predicted diffusing capacity of carbon monoxide (%predicted DLCO), using Pearson's correlation test. RESULTS: Mean ADC and standard deviation values were 0.392+/-0.119 cm(2)/s for the established emphysema group and 0....... Correlations between mean ADC and EI and 15th percentile were both r=0.90 and for MLD r=0.59. There was higher correlation between mean ADC and %predicted DLCO (r=0.90) than between EI and %predicted DLCO (r=0.76). CONCLUSION: HP (3)He-MRI correlates well with density measurements from MSCT and agrees better...

Note: Coincidence measurements of 3He and neutrons from a compact D-D neutron generator

Science.gov (United States)

Ji, Q.; Lin, C.-J.; Tindall, C.; Garcia-Sciveres, M.; Schenkel, T.; Ludewigt, B. A.

2017-05-01

Tagging of neutrons (2.45 MeV) with their associated 3He particles from deuterium-deuterium (D-D) fusion reactions has been demonstrated in a compact neutron generator setup enabled by a high brightness, microwave-driven ion source with a high fraction of deuterons. Energy spectra with well separated peaks of the D-D fusion reaction products, 3He, tritons, and protons, were measured with a silicon PIN diode. The neutrons were detected using a liquid scintillator detector with pulse shape discrimination. By correlating the 3He detection events with the neutron detection in time, we demonstrated the tagging of emitted neutrons with 3He particles detected with a Si PIN diode detector mounted inside the neutron generator vacuum vessel.

Apparent violation of isospin symmetry in the 3H(3He,2H)4He reaction

International Nuclear Information System (INIS)

Rai, G.; Blyth, C.O.; England, J.B.A.; Farooq, A.; Karban, O.; Rawas, E.; Roman, S.; Vlastou, R.

1988-01-01

Angular distributions of the vector analyzing powers for the 3 H( 3 He, 2 H) 4 He reaction have been measured over the incident energy range 18--33 MeV. The measurements centered about 18 MeV display a deviation from the antisymmetric shape expected from isospin symmetry. Concentrating on the explanation of the 90 0 analyzing powers, we report the results of a distorted-wave Born approximation (DWBA) analysis which includes the direct and exchange processes and the spin-orbit potential. It is shown that the anomalous behavior of the 90 0 vector analyzing powers can be largely explained by the effect of a single F-wave potential resonance which leads to the magnification of the short-range differences between the 3 He and 3 H wave functions

Annihilation of antiprotons at rest in 3He and 4He

International Nuclear Information System (INIS)

Balestra, F.; Bossolasco, S.; Bussa, M.P.; Busso, L.; Fava, L.; Ferrero, L.; Panzieri, D.; Piragino, G.; Tosello, F.; Bendiscioli, G.; Rotondi, A.; Salvini, P.; Zenoni, A.; Batusov, Yu.A.; Bunyatov, S.A.; Falomkin, I.V.; Nichitiu, F.; Pontecorvo, G.B.; Sapozhnikov, M.G.; Tretyak, V.I.; Guaraldo, C.; Maggiora, A.; Haatuft, A.; Halsteinslid, A.; Myklebost, K.; Olsen, J.M.; Breivik, F.O.; Jacobsen, T.; Soerensen, S.O.

1987-01-01

At LEAR of CERN the annihilation of antiprotons, stopping in 3 He and 4 He filling a self-shunted streamer chamber in a magnetic field, has been studied. The charged-particle multiplicities have been measured and the relative probabilities of π - production in anti p 3 He and anti p 4 He annihilation events have been obtained. The ratio between the anti p annihilation probability on the neutron and the proton for 3 He and 4 He has been deduced to be about half the value obtained for 2 H in bubble chamber experiments. The analysis of the results shows that this difference cannot be due only to the pion final-state interaction or to the shadow effect of the nucleons of the nuclei. The probability of anti p annihilation at rest on a proton bound in the nucleus results to be twice as high as that on a bound neutron, showing the dominance of annihilation in the I=0 isospin states. (orig.)

Variations of 3/He/4He isotope ratios within the Broadlands geothermal field, New Zealand

International Nuclear Information System (INIS)

Hulston, John; Lupton, John; University of California, Santa Barbara; Rosenberg, Nina

1986-01-01

The Broadlands-Ohaaki geothermal field is located 20 km NE of Wairakei on the Central Volcanic Zone of New Zealand. It falls within a resistivity low extending 4 km by 3 km. A study of 3 He/ 4 He ratios within this field has shown R/R A ratios close to 6.0 in the Ohaaki production area (NW). In contrast the production area to the SE on the east bank of the Waikato River has R/R A values close to 3.5. Differences in chemical ratios reported previously are found to correlate with the 3 He/ 4 He measurements. A tentative interpretation of the results indicate that there is a contribution of 3 He from the mantle and that the variations in the 3 He/ 4 He ratios are probably related to differences in the geochemistry of the rocks through which the geothermal fluids flow to the surface. Preliminary measurements of the argon isotopes also show a contribution from radiogenic rocks at depth

Neutron scattering lengths of 3He

International Nuclear Information System (INIS)

Alfimenkov, V.P.; Akopian, G.G.; Wierzbicki, J.; Govorov, A.M.; Pikelner, L.B.; Sharapov, E.I.

1976-01-01

The total neutron scattering cross-section of 3 He has been measured in the neutron energy range from 20 meV to 2 eV. Together with the known value of coherent scattering amplitude it leads to the two sts of n 3 He scattering lengths

Primary populations of metastable antiprotonic $^{4}He$ and $^{3}He$ atoms

CERN Document Server

Hori, Masaki; Hayano, R S; Ishikawa, T; Sakuguchi, J; Tasaki, T; Widmann, E; Yamaguchi, H; Torii, H A; Juhász, B; Horváth, D; Yamazaki, T

2002-01-01

Initial population distributions of metastable antiprotonic **4He and **3He atoms over principal and angular momentum quantum numbers were investigated using laser spectroscopy. The total fractions of antiprotons captured into the metastable states of the atoms were deduced. Cascade calculations were performed using the measure populations to reproduce the delayed annihilation time spectrum. Results showed agreement between the simulated and measured spectra. (Edited abstract) 30 Refs.

Thermal transport properties in dilute 3He-4He mixtures near the superfluid transition

International Nuclear Information System (INIS)

Tuttle, J.G.

1991-01-01

The author describes measurements of various transport properties of dilute liquid 3 He- 4 He mixtures in two different sample cells. One cell was designed to measure the temperature drop ΔT across a fluid layer due to an applied heat flux Q, and the other allowed measurement of both ΔT and ΔX, the molar concentration drop. He studied the anomalous boundary resistance, ΔR b , in superfluid 4 He near T λ for Q between 4 and 100μW/cm 2 . He presents results for both the weakly divergent and the heat dependent, more strongly divergent contributions. He compares his data with those of Duncan and Ahlers and with theoretical predictions by Frank and Dohm. He also presents similar R b data for a mixture with X = 2.5 x 10 -6 . He determined the relaxation time τ for transients observed during thermal conductivity κ eff and thermal diffusion k T * measurements in superfluid mixtures between 1.7K and T λ with X ranging from 10 -6 to 5 x 10 -2 . He compares these results, taken with a fluid layer thickness h = 1.81 mm, with theoretical predictions and with earlier data for h = 1.47 mm. He shows the mass diffusion coefficient D computed both from τ and from κ eff data for 0.001 λ , and he compares the results of these two different determinations. In addition, he presents the 3 He-roton scattering cross section calculated using D results. In the normal phase he measured the thermal diffusion ratio k T and the thermal conductivity κ for 0.009 ≤ X ≤ 0.05 near T λ , and he compares these results with predictions by Dohm and Folk

Angular dependence of the sup(6)Li(πsup(+),sup(3)He)sup(3)He reaction

International Nuclear Information System (INIS)

McParland, B.J.; Auld, E.G.; Couvert, P.

1985-02-01

Angular distributions of the differential cross sections for the pionic fission sup(6)Li(πsup(+),sup(3)He)sup(3)He have been measured at pion energies of 60 and 80 MeV. The differential cross section is found to decrease monotonically with cossup(2)thetasup(*) and is compared with a theoretical prediction

Goal-Oriented Self-Adaptive hp Finite Element Simulation of 3D DC Borehole Resistivity Simulations

KAUST Repository

Calo, Victor M.

2011-05-14

In this paper we present a goal-oriented self-adaptive hp Finite Element Method (hp-FEM) with shared data structures and a parallel multi-frontal direct solver. The algorithm automatically generates (without any user interaction) a sequence of meshes delivering exponential convergence of a prescribed quantity of interest with respect to the number of degrees of freedom. The sequence of meshes is generated from a given initial mesh, by performing h (breaking elements into smaller elements), p (adjusting polynomial orders of approximation) or hp (both) refinements on the finite elements. The new parallel implementation utilizes a computational mesh shared between multiple processors. All computational algorithms, including automatic hp goal-oriented adaptivity and the solver work fully in parallel. We describe the parallel self-adaptive hp-FEM algorithm with shared computational domain, as well as its efficiency measurements. We apply the methodology described to the three-dimensional simulation of the borehole resistivity measurement of direct current through casing in the presence of invasion.

The Velocity Distribution Of Pickup He+ Measured at 0.3 AU by MESSENGER

Science.gov (United States)

Gershman, Daniel J.; Fisk, Lennard A.; Gloeckler, George; Raines, Jim M.; Slavin, James A.; Zurbuchen, Thomas H.; Solomon, Sean C.

2014-06-01

During its interplanetary trajectory in 2007-2009, the MErcury Surface, Space ENvrionment, GEochemistry, and Ranging (MESSENGER) spacecraft passed through the gravitational focusing cone for interstellar helium multiple times at a heliocentric distance R ≈ 0.3 AU. Observations of He+ interstellar pickup ions made by the Fast Imaging Plasma Spectrometer sensor on MESSENGER during these transits provide a glimpse into the structure of newly formed inner heliospheric pickup-ion distributions. This close to the Sun, these ions are picked up in a nearly radial interplanetary magnetic field. Compared with the near-Earth environment, pickup ions observed near 0.3 AU will not have had sufficient time to be energized substantially. Such an environment results in a nearly pristine velocity distribution function that should depend only on pickup-ion injection velocities (related to the interstellar gas), pitch-angle scattering, and cooling processes. From measured energy-per-charge spectra obtained during multiple spacecraft observational geometries, we have deduced the phase-space density of He+ as a function of magnetic pitch angle. Our measurements are most consistent with a distribution that decreases nearly monotonically with increasing pitch angle, rather than the more commonly modeled isotropic or hemispherically symmetric forms. These results imply that pitch-angle scattering of He+ may not be instantaneous, as is often assumed, and instead may reflect the velocity distribution of initially injected particles. In a slow solar wind stream, we find a parallel-scattering mean free path of λ || ~ 0.1 AU and a He+ production rate of ~0.05 m-3 s-1 within 0.3 AU.

Superfluidity in two-dimensions. A thermal conductivity study of 4He and 3He- 4He mixture films

International Nuclear Information System (INIS)

Finotello, D.

1992-01-01

We review measurement of the thermal transport of 4 He films and 3 He- 4 He mixture films near the superfluid transition. These measurements were performed on helium films of thickness ranging from 12 to 156 A and mixture films with 3 He concentration up to 2%. The superfluid transition temperature for these films ranged from 1.2 to 2.2. K. We discuss universal features of the data as well as the behavior of the ratio of the vortex diffusion constant to vortex core-parameter, the sharpness of the transition and the superfluid transition temperature as a function of thickness and concentration. We also describe new experiments that will contribute to a better understanding of the observed behavior (Author)

Opportunities for Polarized He-3 in RHIC and EIC

Energy Technology Data Exchange (ETDEWEB)

Aschenauer E.; Deshpande, A.; Fischer, W.; Derbenev, S.; Milner, R.; Roser, T.; Zelenski, A.

2011-10-01

The workshop on opportunities for polarized He-3 in RHIC and EIC was targeted at finding practical ways of implementing and using polarized He-3 beams. Polarized He-3 beams will provide the unique opportunity for first measurements, i.e, to a full quark flavor separation measuring single spin asymmetries for p{sup +}, p{sup -} and p{sup 0} in hadron-hadron collisions. In electron ion collisions the combination of data recorded with polarized electron proton/He-3 beams allows to determine the quark flavor separated helicity and transverse momentum distributions. The workshop had sessions on polarized He-3 sources, the physics of colliding polarized He-3 beams, polarimetry, and beam acceleration in the AGS Booster, AGS, RHIC, and ELIC. The material presented at the workshop will allow making plans for the implementation of polarized He-3 beams in RHIC.

Superfluidity of a dilute 3He-4He solution

International Nuclear Information System (INIS)

Soda, Toshio

1993-01-01

The interaction between two 3 He atoms is calculated by taking into account the backflow effect of 3 He by the 4 He in the 3 He- 4 He mixture. The effect contributes solely to the P wave part of the interaction. The repulsive S wave part of the contact interaction contributes to the exchange interaction between the 3 He atoms, while the direct one phonon exchange interaction contributes both to the S and P wave attractive interactions. The overall contribution to the attractive interaction is dominated by the P wave part and the superfluidity in the P wave is more predominant than in the S wave for the 5 % dilute 3 He- 4 He solution, and vice versa for the 1.3 % solution. (author)

Non-intrusive measurement of tritium activity in waste drums by modelling a 3He leak quantified by mass spectrometry

International Nuclear Information System (INIS)

Demange, D.

2002-01-01

This study deals with a new method that makes it possible to measure very low tritium quantities inside radioactive waste drums. This indirect method is based on measuring the decaying product, 3 He, and requires a study of its behaviour inside the drum. Our model considers 3 He as totally free and its leak through the polymeric joint of the drum as two distinct phenomena: permeation and laminar flow. The numerical simulations show that a pseudo-stationary state takes place. Thus, the 3 He leak corresponds to the tritium activity inside the drum but it appears, however, that the leak peaks when the atmospheric pressure variations induce an overpressure in the drum. Nevertheless, the confinement of a drum in a tight chamber makes it possible to quantify the 3 He leak. This is a non-intrusive measurement of its activity, which was experimentally checked by using reduced models, representing the drum and its confinement chamber. The drum's confinement was optimised to obtain a reproducible 3 He leak measurement. The gaseous samples taken from the chamber were purified using selective adsorption onto activated charcoals at 77 K to remove the tritium and pre-concentrate the 3 He. The samples were measured using a leak detector mass spectrometer. The adaptation of the signal acquisition and the optimisation of the analysis parameters made it possible to reach the stability of the external calibrations using standard gases with a 3 He detection limit of 0.05 ppb. Repeated confinement of the reference drums demonstrated the accuracy of this method. The uncertainty of this non-intrusive measurement of the tritium activity in 200-liter drums is 15% and the detection limit is about 1 GBq after a 24 h confinement. These results led to the definition of an automated tool able to systematically measure the tritium activity of all storage waste drums. (authors)

Observation of the Rotational Spectra of 4HeH+, 4HeD+, 3HeH+, and 3HeD+

International Nuclear Information System (INIS)

Matsushima, F.; Oka, T.; Takagi, K.

1997-01-01

Low J rotational transitions of 4 HeH + , 4 HeD + , 3 HeH + , and 3 HeD + were observed in the 2 endash 5THz region with a high-precision far-infrared spectrometer. Dunham coefficients Y kl and isotopically independent parameters U kl , Δ He kl , and Δ H kl were determined. In particular, Δ parameters with k=0 and l=1,2 were determined with unprecedented accuracy, and provide important information for breakdown of the Born-Oppenheimer approximation. The lowest J=1 left-arrow 0 transition of 4 HeH + observed at 2010.1839(2)GHz will be an important future probe for detecting this species in space. copyright 1997 The American Physical Society

Comparing Hp(3) evaluated from the conversion coefficients from air kerma to personal dose equivalent for eye lens dosimetry calibrated on a new cylindrical PMMA phantom

Science.gov (United States)

Esor, J.; Sudchai, W.; Monthonwattana, S.; Pungkun, V.; Intang, A.

2017-06-01

Based on a new occupational dose limit recommended by ICRP (2011), the annual dose limit for the lens of the eye for workers should be reduced from 150 mSv/y to 20 mSv/y averaged over 5 consecutive years in which no single year exceeding 50 mSv. This new dose limit directly affects radiologists and cardiologists whose work involves high radiation exposure over 20 mSv/y. Eye lens dosimetry (Hp(3)) has become increasingly important and should be evaluated directly based on dosimeters that are worn closely to the eye. Normally, Hp(3) dose algorithm was carried out by the combination of Hp(0.07) and Hp(10) values while dosimeters were calibrated on slab PMMA phantom. Recently, there were three reports from European Union that have shown the conversion coefficients from air kerma to Hp(3). These conversion coefficients carried out by ORAMED, PTB and CEA Saclay projects were performed by using a new cylindrical head phantom. In this study, various delivered doses were calculated using those three conversion coefficients while nanoDot, small OSL dosimeters, were used for Hp(3) measurement. These calibrations were performed with a standard X-ray generator at Secondary Standard Dosimetry Laboratory (SSDL). Delivered doses (Hp(3)) using those three conversion coefficients were compared with Hp(3) from nanoDot measurements. The results showed that percentage differences between delivered doses evaluated from the conversion coefficient of each project and Hp(3) doses evaluated from the nanoDots were found to be not exceeding -11.48 %, -8.85 % and -8.85 % for ORAMED, PTB and CEA Saclay project, respectively.

Moisture distribution measurements in adhesive-bonded composites using the D (3He,p)4 He reaction

International Nuclear Information System (INIS)

Schulte, R.L.; Deiasi, R.J.

1981-01-01

Adhesive bonding of composite materials for many aircraft components offers a distinct advantage in weight and cost reduction compared to similar structures that have been joined by riveting. However, the long term performance of adhesive-bonded components depends on the degree and rate of moisture absorption by the adhesive in the service environment. To investigate the rate and the mechanism of water transport in adhesive-bonded composite materials, a nuclear reaction analysis method based on the D( 3 He,p) 4 He reaction is used to measure the moisture distributions. Samples of graphite/epoxy composite materials were bonded with an epoxy adhesive and isothermally conditioned in a controlled D 2 O environment at 70% relative humidity and 77 0 C for various exposure times. The moisture profiles were measured along the adhesive (adhesive scan) as well as through the thickness of the bonded joint (transverse scan). The dimensions of the probing beam were 125 μm x 125 μm for the adhesive scan and 25 μ x 200 μm for the transverse scan. Absolute deuterium concentrations were determined by comparison of the proton yield from the composite/adhesive to that from reference standards. Calculations from diffusion models of water transport based on parameters determined from bulk measurement techniques are compared to the measured profile and the agreement indicates that classical Fickian diffusion describes the transport of moisture in these materials

The osmotic pressure of 3He-4He mixtures along the phase separation curve

NARCIS (Netherlands)

van de Klundert, L.J.M.; Bos, M.R.E.; van der Meij, J.A.M.; Steffens, H.A.

1977-01-01

The osmotic pressure of 3He-4He mixtures was measured along the phase separation curve at temperatures up to 500 mK by balancing it with the fountain pressure of pure 4He. The usefullness of the secondary osmotic pressure thermometer was reinvestigated.

The osmotic pressure of 3He-4He mixtures along the phase separation curve

International Nuclear Information System (INIS)

Klundert, L.J.M. van de; Bos, M.R.E.; Meij, J.A.M. van der; Steffens, H.A.

1977-01-01

The osmotic pressure of 3 He- 4 He mixtures was measured along the phase separation curve at temperatures up to 500 mK by balancing it with the fountain pressure of pure 4 He. The usefullness of the secondary osmotic pressure thermometer was reinvestigated. (Auth.)

Measurement of "pretzelosity" asymmetry of charged pion production in semi-inclusive deep inelastic scattering on a polarized 3He target

Science.gov (United States)

Zhang, Y.; Qian, X.; Allada, K.; Dutta, C.; Huang, J.; Katich, J.; Wang, Y.; Aniol, K.; Annand, J. R. M.; Averett, T.; Benmokhtar, F.; Bertozzi, W.; Bradshaw, P. C.; Bosted, P.; Camsonne, A.; Canan, M.; Cates, G. D.; Chen, C.; Chen, J.-P.; Chen, W.; Chirapatpimol, K.; Chudakov, E.; Cisbani, E.; Cornejo, J. C.; Cusanno, F.; Dalton, M. M.; Deconinck, W.; de Jager, C. W.; De Leo, R.; Deng, X.; Deur, A.; Ding, H.; Dolph, P. A. M.; Dutta, D.; El Fassi, L.; Frullani, S.; Gao, H.; Garibaldi, F.; Gaskell, D.; Gilad, S.; Gilman, R.; Glamazdin, O.; Golge, S.; Guo, L.; Hamilton, D.; Hansen, O.; Higinbotham, D. W.; Holmstrom, T.; Huang, M.; Ibrahim, H. F.; Iodice, M.; Jiang, X.; Jin, G.; Jones, M. K.; Kelleher, A.; Kim, W.; Kolarkar, A.; Korsch, W.; LeRose, J. J.; Li, X.; Li, Y.; Lindgren, R.; Liyanage, N.; Long, E.; Lu, H.-J.; Margaziotis, D. J.; Markowitz, P.; Marrone, S.; McNulty, D.; Meziani, Z.-E.; Michaels, R.; Moffit, B.; Muñoz Camacho, C.; Nanda, S.; Narayan, A.; Nelyubin, V.; Norum, B.; Oh, Y.; Osipenko, M.; Parno, D.; Peng, J. C.; Phillips, S. K.; Posik, M.; Puckett, A. J. R.; Qiang, Y.; Rakhman, A.; Ransome, R. D.; Riordan, S.; Saha, A.; Sawatzky, B.; Schulte, E.; Shahinyan, A.; Shabestari, M. H.; Širca, S.; Stepanyan, S.; Subedi, R.; Sulkosky, V.; Tang, L.-G.; Tobias, W. A.; Urciuoli, G. M.; Vilardi, I.; Wang, K.; Wojtsekhowski, B.; Yan, X.; Yao, H.; Ye, Y.; Ye, Z.; Yuan, L.; Zhan, X.; Zhang, Y.-W.; Zhao, B.; Zheng, X.; Zhu, L.; Zhu, X.; Zong, X.; Jefferson Lab Hall A Collaboration

2014-11-01

An experiment to measure single-spin asymmetries of semi-inclusive production of charged pions in deep-inelastic scattering on a transversely polarized 3He target was performed at Jefferson Laboratory in the kinematic region of 0.16 3He, which are expressed as the convolution of the h1T ⊥ transverse-momentum-dependent distribution functions and the Collins fragmentation functions in the leading order, were measured for the first time. Under the effective polarization approximation, we extracted the corresponding neutron asymmetries from the measured 3He asymmetries and cross-section ratios between the proton and 3He. Our results show that both π± on 3He and on neutron pretzelosity asymmetries are consistent with zero within experimental uncertainties.

High resolution measurements of the He-He total scattering cross section for reduced collision energies between 0.2 and 200

International Nuclear Information System (INIS)

Feltgen, R.; Koehler, K.A.; Pauly, H.; Torello, F.; Vehmeyer, H.

1974-01-01

The energy dependence of the total scattering cross section is measured for the isotopic systems He 4 -He 4 and He 3 -He 3 using a velocity selected He primary beam and a He target in a scattering chamber maintained at 1.57 deg K. In the low energy region both systems show a pronounced atomic Ramsauer-Townsend effect. At higher energies 13 backward glory extrema in the case of He 4 -He 4 and 10 extrema for He 3 -He 3 are observed. From these extrema the energy dependence of the s-phase shift can be derived. Applying the semiclassical inversion method proposed by Miller it is possible to compute the repulsive potential in the energy range of the measurement

Quasielastic 3Hp scattering at 2.5 GeV/c triton momentum

International Nuclear Information System (INIS)

Blinov, A.V.; Chuvilo, I.V.; Ergakov, V.A.

1982-01-01

The differential cross sections of the quasielastic 3 Hp-scattering at a 2.5 GeV/c tritium momentum (Tsub(p)=318 MeV) have been measured using the ITEP 80 cm hydrogen buble chamber. The experimental results are compared with the predictions of the Glauber-Sitenke multiple scattering theory combined with the the completeness condition for the excited nucleus wave functions. The validity of the Glauber sum rule for the differential cross sections is investigated

Phase equilibrium in a polarized saturated 3He-4He mixture

International Nuclear Information System (INIS)

Rodrigues, A.; Vermeulen, G.

1997-01-01

We present experimental results on the phase equilibrium of a saturated 3 He- 4 He mixture, which has been cooled to a temperature of 10-15 mK and polarized in a 4 He circulating dilution refrigerator to a stationary polarization of 15 %, 7 times higher than the equilibrium polarization in the external field of 7 T. The pressure dependence of the polarization enhancement in the refrigerator shows that the molar susceptibilities of the concentrated and dilute phase of a saturated 3 He- 4 He mixture are equal at p = 2.60 ± 0.04 bar. This result affects the Fermi liquid parameters of the dilute phase. The osmotic pressure in the dilute phase has been measured as a function of the polarization of the coexisting concentrated phase up to 15 %. We find that the osmotic pressure at low polarization ( < 7 % ) agrees well with thermodynamics using the new Fermi liquid parameters of the dilute phase

Measurement of personal equivalent dose Hp(3) during procedures involving in positron emission tomography; Medida del equivalente de dosis personal en cristalino Hp(3) durante los procedimientos asociados a la tomografía por emisión de positrones

Energy Technology Data Exchange (ETDEWEB)

Guiu Souto, J.; Sánchez García, M.; Vázquez, R.; Pardo Montero, J.; Pombar Cameán, M.

2017-11-01

The aim of the present study consists to determinate the personal equivalent dose Hp(3) at eye lens during the procedures involved in positron emission tomography. We have monitored the nurse's staff which is responsible of handling and dispensing 18F. We characterize the relevant stages as the preparation, the transport and the administration of monodose syringes in terms of occupational dose. We observed that the preparation presents a major contribution to the occupational doses than the other stages. In addition, during those stage there is a correlation between the dose increments and handling activity. To establish the eye lens dose we use the following dosimetry set: a direct readout solid state dosimeter for general purposes calibrated at Hp(10) and a set of thermolumiscent dosimeters specific for 18F calibrated at Hp(3). Finally, for the dose intercomparison between above dosimeters we obtain a correction factor by Monte Carlo. The eye lens dose, with a value of 2.8 ± 0.4 mSv/yr, results more critical than the dose obtained in other locations, as extremities. [Spanish] El propósito del presente trabajo consiste en la determinación del equivalente de dosis personal Hp(3) en cristalino durante los procedimientos asociados a la tomografía por emisión de positrones. Se ha monitorizado al personal de enfermería que realiza las tareas de manipulación y dispensación del 18F. Se ha realizado un estudio caracterizando la dosis en las etapas más relevantes del procedimiento: la preparación manual de las jeringuillas, el transporte de las mismas y su posterior administración al paciente. Se observó que la preparación es la etapa que más contribuye a la dosis ocupacional, además durante dicha etapa se observa una clara correlación entre el incremento de dosis y la actividad manipulada. Para determinar la dosis en cristalino se ha utilizado el siguiente equipo dosimétrico: un detector de estado sólido de lectura directa de propósito general

Growth and dissolution of liquid 3He droplets in solid 4He matrix

International Nuclear Information System (INIS)

Gan'shin, A.N.; Grigor'ev, V.N.; Majdanov, V.A.; Penzev, A.A.; Rudavskij, Eh.Ya.; Rybalko, A.S.

2000-01-01

The phase separation kinetics of solid 3 He - 4 He mixtures was investigated using pressure measurements in the conditions when the two-phase system formed consists of concentrated phase liquid droplets (almost pure 3 He) in the dilute phase crystal matrix (almost pure 4 He). It is shown that the liquid droplet growth may be described by a sum of two exponential processes with small and large time contacts as cooling down step by step. This is a result of the strong influence of strains which appear in the crystal at the phase separation due to a large difference in molar volume between the phases and probably give rise to plastic deformation of the matrix and to non-equilibrium 3 He concentration in it. The 3 He atom transfer occurs only to the extent of strain relaxation. It is found that the cyclic growth and dissolution of the liquid droplets affect the crystal quality and lead to pressure increase. The coexistence of liquid and solid phases in droplets is speculated to be possible

Capture of ions by vortex lines in pure 4He and 3He--4He solutions

International Nuclear Information System (INIS)

Ostermeier, R.M.; Glaberson, W.I.

1975-01-01

Measurements of the capture cross section for the negative ion by vortex lines in pure 4 He and a 0.94 percent solution of 3 He in 4 He are presented. A measurable capture of positive ions was not observed in either system. In pure 4 He the departure of the experimental data from the predictions of stochastic theory at lower temperatures is explained in terms of a simple breakdown in that theory, and lifetime effects are shown to be of only secondary importance. The decrease in cross section with decreasing temperature, due essentially to a reduced number density of rotons, is predicted by the results of a Monte Carlo calculation. The cross section in the solution follows stochastic theory to significantly lower temperatures, but at about 1 K there again occurs a marked discrepancy. Measurements of the ion trapping lifetime at low temperatures indicate that it is the finite lifetime that accounts for this discrepancy. Elimination of lifetime effects results in fair agreement between the cross section data in the solution and the predictions of stochastic theory. (11 figures) (auth)

Study of the 6Li + p → 3He + 4He reaction in inverse kinematics

International Nuclear Information System (INIS)

Betsou, C.; Pakou, A.; Aslanoglou, X.; Nicolis, N.G.; Sgouros, O.; Soukeras, V.; Cappuzzello, F.; Acosta, L.; Agodi, C.; Carbone, D.; Cavallaro, M.; Di Pietro, A.; Fernandez-Garcia, J.P.; Figuera, P.; Fisichella, M.; Foti, A.; Keeley, N.; Marquinez-Duran, G.; Martel, I.; Mazzocco, M.; Strano, E.; Torresi, D.; Pierroutsakou, D.; Rusek, K.; Stiliaris, E.

2015-01-01

Angular distribution measurements were performed for the 6 Li + p → 3 He + 4 He reaction in inverse kinematics at incident energies of 2.7, 3.3, 4.2 and 4.8 MeV/u. The detection of both recoils ( 3 He and 4 He) over the laboratory angle range θ lab = 16 circle to 34 circle allowed the determination of the angular distribution over a wide angular range in the center-of-mass frame (θ c.m. ∝ 40 circle to 140 circle ). The results clarify inconsistencies between existing data sets and are consistent with compound nucleus model calculations. (orig.)

Exchange currents in low-energy nucleon capture by 3He

International Nuclear Information System (INIS)

Wervelman, Rob.

1991-01-01

The studies described in this thesis concern absolute cross-section measurements of the radiative neutron capture reactions 3 He (n,γ) 4 He and 3 He(n,γγ) 4 He, and are complements with shell-model calculations on the radiative thermal neutron capture reaction by 3 He and on the weak 3 He(p,e + ν e ) 4 He reaction. The experiments have been performed at two neutron energies, with sub-thermal neutrons where s-wave capture is dominant, and with a quasi-monochromatic 24.5 keV neutron beam (p-wave capture). It has been found that the thermal neutron capture cross section of 3 He is 55±3 μb. Measured at 24.5 keV-neutron energy, the radiative capture cross section for p-wave neutrons turned out to be 9.1±0.8 μb. A measurement on the double-photon reaction 3 He(n th ,γγ) has yielded a cross-section value of 30±80 μb. In the theoretical part of the work a standard model of nuclear weak and electromagnetic interaction currents, consisting of a one-body impulse approximation and a two-body meson-exchange current part, has been applied to the process of nucleon capture by 3 He. Within the framework of a (0+2) (h/2π)ω shell-model calculation, using Sussex matrix elements for the 3 He and 4 He ground state wave functions, the empirical radiative cross sections for thermal neutrons of 3 He could be reproduced with satisfactory agreement. The total MEC correction to the radiative thermal neutron capture cross section is rather small because large cancellations occur between the various contributions. In the 3 He(p,e + ν e ) 4 He reaction meson-exchange contributions enlarge the astrophysical S-factor by more than a factor two. The matrix element ratio of the weak 3 He+p and the electromagnetic 3 He+n reaction is calculated to be (4.3±0.6)g A C 0 . This ratio has been found to be fairly insensitive to the percentage D-state admixtures in the 3 He and 4 He ground state wave functions. (author). 129 refs.; 24 figs.; 5 tabs

Galactic evolution of D and 3He including stellar production of 3He

International Nuclear Information System (INIS)

Dearborn, D.S.; Steigman, G.; Tosi, M.

1996-01-01

New stellar models which track the production and destruction of 3 He (and D) have been evolved for a range of stellar masses (0.65≤M/M circle-dot ≤100), metallicities (0.01≤Z/Z circle-dot ≤1), and initial (main-sequence) 3 He mass fractions (10 -5 ≤X 3,MS ≤10 -3 ). Armed with the 3 He yields from these stellar models we have followed the evolution of D and 3 He using a variety of chemical evolution models with and without infall of primordial or processed material. Production of new 3 He by the lower mass stars overwhelms any reasonable primordial contributions and leads to predicted abundances in the presolar nebula and/or the present interstellar medium in excess of the observationally inferred values. This result, which obtains even for zero primordial D and 3 He, and was anticipated by Rood, Steigman, ampersand Tinsley is insensitive to the choice of chemical evolution model; it is driven by the large 3 He yields from low-mass stars. In an attempt to ameliorate this problem we have considered a number of nonstandard models in which the yields from low-mass stars have been modified. Although several of these nonstandard models may be consistent with the 3 He data, they may be inconsistent with observations of 12 C/ 13 C, 18 O, and, most seriously the super- 3 He rich planetary nebulae. Even using the most extreme of these nonstandard models we obtain a generous upper bound to pregalactic 3 He:X 3P ≤3.2x10 -5 which, nonetheless, leads to a stringent lower bound to the universal density of nucleons. copyright 1996 The American Astronomical Society

A measurement of the absolute neutron beam polarization produced by an optically pumped 3He neutron spin filter

International Nuclear Information System (INIS)

Rich, D.R.; Bowman, J.D.; Crawford, B.E.; Delheij, P.P.J.; Espy, M.A.; Haseyama, T.; Jones, G.; Keith, C.D.; Knudson, J.; Leuschner, M.B.; Masaike, A.; Masuda, Y.; Matsuda, Y.; Penttilae, S.I.; Pomeroy, V.R.; Smith, D.A.; Snow, W.M.; Szymanski, J.J.; Stephenson, S.L.; Thompson, A.K.; Yuan, V.

2002-01-01

The capability of performing accurate absolute measurements of neutron beam polarization opens a number of exciting opportunities in fundamental neutron physics and in neutron scattering. At the LANSCE pulsed neutron source we have measured the neutron beam polarization with an absolute accuracy of 0.3% in the neutron energy range from 40 meV to 10 eV using an optically pumped polarized 3 He spin filter and a relative transmission measurement technique. 3 He was polarized using the Rb spin-exchange method. We describe the measurement technique, present our results, and discuss some of the systematic effects associated with the method

Structural effects at Λ3Hp-scattering

International Nuclear Information System (INIS)

Tartakovskij, V.K.; Fursaev, A.V.; Ivanova, O.I.

2003-01-01

In the paper the calculated dependences of falling hyper-tritons energy E=156 MeV differential cross sections from the scattering angle in the center of mass system θ and for more high energy values E from coupling energy ε 0 of Λ 3 H with regard to its disintegration into Λ-hyperon and deuteron are presented. It is established the strong dependence of differential cross section from ε 0 , moreover the sensitivity of differential cross sections to ε 0 value grows up with increasing of energy E. This allows to use the Λ 3 Hp-scattering as a method for ε 0 value elaboration

The effect of Demkov coupling in the rotational predissociation of 3He4He+, ch. 4

International Nuclear Information System (INIS)

Asselt, N.P.F.B. van; Maas, J.G.; Los, J.

1976-01-01

The momentum distribution of the 3 He + and the 4 He + fragments, both originating from rotational predissociation of 3 He 4 He + has been measured. There is a pronounced difference between the intensity distributions in both spectra. This difference is explained as the result of a Demkov coupling between the two lowest electronic states of the molecular ion. The rotational quantum numbers of the states involved are calculated from the spectra

Measurement of the 6He Decay Produced by the 9Be(n, α) 6 He Reaction

Science.gov (United States)

Cook, Katelyn; Coats, Micah; Yuly, Mark; Padalino, Stephen; Sangster, Craig; Regan, Sean

2016-10-01

The OMEGA laser at LLE is routinely used to implode gas-filled capsules to study light ion fusion reaction rates of interest to stellar nucleosynthesis. As a first step toward a possible measurement of the 3H(t,γ)6He radiative capture reaction, a detector system capable of measuring the 801 ms half-life of 6He has been developed and is being tested using 6He nuclei produced via the 9Be(n,α)6He reaction. Deuterons from the SUNY Geneseo tandem Pelletron produce neutrons in a thick deuterated polyethylene target via the 2H(d,n)3He reaction. These neutrons are allowed to strike a beryllium target placed in front of a silicon ΔE-E detector telescope, which is used to identify the β particles from 6He decay. Following an approximately five second long activation period, the beryllium sample is immediately counted for about five seconds. The pulse heights for each detector and the timestamp are recorded using a specially configured femtoDAQ acquision system and used to measure the decay curve. Funded in part by a Grant from the DOE through the Laboratory for Laser Energetics.

Energy dependence of the 3He(3He,π+)6Li reaction

International Nuclear Information System (INIS)

Le Bornec, Y.; Hibou, F.; Bimbot, L.; Hennino, T.; Jourdain, J.C.; Reide, F.; Tatischeff, B.; Willis, N.; Aslanides, E.; Bergdolt, G.; Fassnacht, P.; Racca, C.; Boudard, A.; Bruge, G.; Lugol, J.C.

1983-01-01

The 3 He( 3 He, π + ) 6 Li reaction has been studied as a function of energy using the 3 He beam at SATURNE. Cross sections for the 6 Li ground state (1 + ) and 2.18 MeV (3 + ) levels have been obtained at 350, 420, 500 and 600 MeV incident energies at angles THETAsub(π)(lab)=15 0 and 40 0 . These results are compared with two theoretical predictions. (orig.)

HP 9816

CERN Multimedia

1982-01-01

The 9816 was introduced in late 1982. This was the low-cost model in the 200 Series range. It only had two expansion slots and featured a monitor integrated with the system unit and modular keyboard and mass storage (usually a 9121 dual 3.5 inch floppy drive). The monitor was nine inches diagonally with a 400 by 300 dot resolution. The HP 9816 was also designated as the HP 9000 216. It did not include any disk drives but it had a built-in 9 inch monochrome monitor, built-in HP-IB and RS-232 ports and 2 expansion slots. The standard keyboard for the 9816 is a itty-bitty number. The 9816 A came with 128K bytes of memory. The 9816 S included all of the above plus disk based BASIC and a card containing an additional 256K of memory bringing the total memory to 512K but only leaving only one expansion slot open.

Calculation of conversion coefficients Hp(3)/K air using the PENELOPE Monte Carlo code and comparison with MCNP calculation results

International Nuclear Information System (INIS)

Daures, J.; Gouriou, J.; Bordy, J.M.

2010-01-01

The authors report calculations performed using the MNCP and PENELOPE codes to determine the Hp(3)/K air conversion coefficient which allows the Hp(3) dose equivalent to be determined from the measured value of the kerma in the air. They report the definition of the phantom, a 20 cm diameter and 20 cm high cylinder which is considered as representative of a head. Calculations are performed for an energy range corresponding to interventional radiology or cardiology (20 keV-110 keV). Results obtained with both codes are compared

Observation of flow dissipation in 3He-B

International Nuclear Information System (INIS)

Eisenstein, J.P.; Packard, R.E.

1982-01-01

Anomalous dissipation is observed in 3 He-B flowing in a U-tube device. The dissipation is of unknown origin and persists to the lowest measured velocity. The position of this result in the framework of other 3 He-B flow experiments is discussed

Cumulative nucleon production in 3Hep- and 3Hp interactions at momenta of colliding nuclei 5 GeV/c

International Nuclear Information System (INIS)

Abdullin, S.K.; Blinov, A.V.; Vanyushin, I.A.

1989-01-01

Inclusive cross sections of cumulative protons produced in 3 Hep- and 3 Hp-interactions under momenta of colliding 5 GeV/c nuclei are investigated. Experimental material is obtained using liquid-hydrogen ITEP chamber-80cm. Under the cumulative proton kinetic energy, exceeding 50 MeV inclusive cross section ratio σ( 3 Hep→pX)/σ( 3 Hp→pX)=1.6±0.1. Within the same energy interval evaluation of yield ratio of cumulative protons and neutrons, produced in 3 Hep -interactions, leads to ∼ 1.6 value. Asymmetry of mean multiple protons escaping forward and backward both in 3 Hep -and in 3 Hp interactions is observed. Averaged invariant distribution functions for cumulative protons and neutrons in 8 Hep-interactions and protons in 3 Hp-interactions are constructed (the averaging is performed within 90-180 deg and 120-180 deg intervals). To temperatures of such distributions are found. 43 refs.; 1 fig

Radiogenic 3He/4He Estimates and Their Effect on Calculating Plio-Pleistocene Cosmogenic 3He Ages of Alluvial-Fan Terraces in the Lower Colorado River Basin, USA

Science.gov (United States)

Fenton, C.; Pelletier, J.

2005-12-01

Several alluvial-fan terraces near Topock, AZ were created by successive entrenchment of Pliocene and Pleistocene alluvial-fan gravels shed from the adjacent Black Mountains along the lower Colorado River corridor below Hoover Dam. These fans interfinger with and overlie main-stem Colorado River sands and gravels and grade to terrace levels that correspond with pre-existing elevations of the Colorado River. Absolute dates for the ages of Quaternary deposits on the lower Colorado River are rare and cosmogenic 3He age estimates of these surfaces would help constrain the timing of aggradation and incision in the lower Colorado River corridor. We analyzed individual basalt boulders from several terrace surfaces for total 3He/4He concentrations to calculate cosmogenic 3He ages of each fan terrace; 3He/4He values, expressed as R/Ra where Ra is the 3He/4He of air, range from 0.29 to 590. Black Mountain volcanic rocks have reported K-Ar ages between 15 and 30 Ma and basalt samples from adjacent alluvial fans contain 0.42 to 47× 1012 at/g of 4He, which has likely accumulated due to nuclear processes. The amount of radiogenic 3He/4He can be significant in old rocks with young exposure ages and can complicate determination of cosmogenic 3 He content. Alpha-decay of U, Th, and their daughter isotopes produces large amounts of 4He, whereas significant amounts of radiogenic 3He are only produced through the neutron bombardment of Li and subsequent beta-decay of tritium. We measured Li, U, Th, major and rare-earth element concentrations in whole-rock basalts and mineral separates. These concentrations are used to estimate the ratio of radiogenic helium contributed to the total helium system in our samples. Li concentrations typically range from 6 to 17 ppm, with one outlier of 62 ppm. U contents range from calculations predict that the average radiogenic helium (R/Ra) contributed to the total helium in Black Mountain basalt samples is 0.011. Other noble gas studies have shown

He3 cryostat

International Nuclear Information System (INIS)

Novichkova, L.G.; Kulikov, Yu.V.; Stashkova, N.M.

1992-01-01

An effective cryostat featuring a one-cycle He 3 refrigerator with a cryosorption pump is described. Gaseous He 3 in contained in a low-pressure vessel having a common wall with a liquid N 2 bath. Due to this, the gas is cooled before sorption and the sorption rate increases approximately by a factor of ten. The cryostat is provided with a needle valve which cuts off the ballast volume of the pipelines from the refrigerator. As a result, the pressure of He 3 vapours increases before condensation and with refrigerator dimensions selected properly, the liquefaction coefficient reaches approximately 80%. Test results of the cryostat and its specifications are presented. (Author)

Measurement of excitation functions and isomeric ratios of the 197Au(3He,xn)200- sup(x)Tl reactions, where x=2,3 and 4

International Nuclear Information System (INIS)

Vinagre Filho, U.M.

1983-01-01

The excitation functions and isomer ratios of the 197 Au( 3 He,xn) 200- sup(x)Tl reactions, with x = 2, 3 and 4, were measured at bombarding energies in the range from 15 to 36 MeV. The measured values were compared to those obtained with the use of the statistical an hybrid modeles, calculated by the ALICE code. Best fit was achieved using the simple statistical model. The results were also compared to those found in literature for the ( 3 He,xn) and ( 4 He,xn) reactions in gold. (Author) [pt

Temperature dependence of He(2 3PJ) reactions: Collision-induced mixing and conversion to He2( 3Πg) molecules

International Nuclear Information System (INIS)

Zhao, X.; Soletsky, P.A.; Bryan, W.H.; Dunning, F.B.; Walters, G.K.

1993-01-01

The rate coefficients for mixing between He(2 3 P J, MJ) levels during collisions with ground-state helium atoms and for conversion of He(2 3 P J ) atoms to He 2 (b 3 Π g ) molecules via three-body reactions in helium gas have been investigated over the temperature range 1.6--300 K. The measured rate coefficients for collisionally induced P-state mixing decrease slowly with decreasing temperature, from (1.8±0.5)x10 -9 cm 3 s -1 at 300 K to (4.5±0.5)x10 -10 cm 3 s -1 at 4.2 K. The rate coefficients for the production of He 2 (b 3 Π g ) molecules via three-body reactions are observed to increase with decreasing temperature and are described by the relation k P congruent(2.5+267T -1 )x10 -32 cm 6 s -1 . This behavior, which is very different from that noted in earlier studies of the conversion of He(2 3 S 1 ) atoms to He 2 (a 3 Σ u + ) molecules through three-body reactions, suggests that the reaction is not thermally activated

Efficient 3He/4He separation in a nanoporous graphenylene membrane.

Science.gov (United States)

Qu, Yuanyuan; Li, Feng; Zhao, Mingwen

2017-08-16

Helium-3 is a precious noble gas, which is essential in many advanced technologies such as cryogenics, isotope labeling and nuclear weapons. The current imbalance of 3 He demand and supply shortage leads to the search for an efficient membrane with high performance for 3 He separation. In this study, based on first-principles calculations, we demonstrated that highly efficient 3 He harvesting can be achieved in a nanoporous graphenylene membrane with industrially-acceptable selectivity and permeance. The quantum tunneling effect leads to 3 He harvesting with high efficiency via kinetic sieving. Both the quantum tunneling effect and zero-point energy (ZPE) determine the 3 He/ 4 He separation via thermally-driven equilibrium sieving, where the ZPE effect dominates efficient 3 He/ 4 He separation between two reservoirs. The quantum effects revealed in this work suggest that the nanoporous graphenylene membrane is promising for efficient 3 He harvesting that can be exploited for industrial applications.

Dynamic variation of histone H3 trimethyl Lys4 (H3K4me3) and heterochromatin protein 1 (HP1) with employment length in nickel smelting workers.

Science.gov (United States)

Zhao, Yanhong; Cheng, Ning; Dai, Min; Pu, Hongquan; Zheng, Tongzhang; Li, Haiyan; He, Jie; Bai, Yana

2017-07-01

To investigate the dynamic variation in H3K4me3 and HP1 with employment length in nickel smelting workers. Blood samples were collected from 140 nickel smelting workers and 140 age-matched office workers to test for H3K4me3, and HP1 levels. H3K4me3 was statistically significantly different (p exposure to nickel can induce oxidative damage, and increase H3K4me3 expression and inhibit HP1 expression.

3He electron scattering sum rules

International Nuclear Information System (INIS)

Kim, Y.E.; Tornow, V.

1982-01-01

Electron scattering sum rules for 3 He are derived with a realistic ground-state wave function. The theoretical results are compared with the experimentally measured integrated cross sections. (author)

A validation of the 3H/3He method for determining groundwater recharge

Science.gov (United States)

Solomon, D. K.; Schiff, S. L.; Poreda, R. J.; Clarke, W. B.

1993-09-01

Tritium and He isotopes have been measured at a site where groundwater flow is nearly vertical for a travel time of 100 years and where recharge rates are spatially variable. Because the mid-1960s 3H peak (arising from aboveground testing of thermonuclear devices) is well-defined, the vertical groundwater velocity is known with unusual accuracy at this site. Utilizing 3H and its stable daughter 3He to determine groundwater ages, we compute a recharge rate of 0.16 m/yr, which agrees to within about 5% of the value based on the depth of the 3H peak (measured both in 1986 and 1991) and two-dimensional modeling in an area of high recharge. Zero 3H/3He age occurs at a depth that is approximately equal to the average depth of the annual low water table, even though the capillary fringe extends to land surface during most of the year at the study site. In an area of low recharge (0.05 m/yr) where the 3H peak (and hence the vertical velocity) is also well-defined, the 3H/3He results could not be used to compute recharge because samples were not collected sufficiently far above the 3H peak; however, modeling indicates that the 3H/3He age gradient near the water table is an accurate measure of vertical velocities in the low-recharge area. Because 3H and 3He have different diffusion coefficients, and because the amount of mechanical mixing is different in the area of high recharge than in the low-recharge area, we have separated the dispersive effects of mechanical mixing from molecular diffusion. We estimate a longitudinal dispersivity of 0.07 m and effective diffusion coefficients for 3H (3HHO) and 3He of 2.4×10-5 and 1.3×10-4 m2/day, respectively. Although the 3H/3He age gradient is an excellent indicator of vertical groundwater velocities above the mid-1960s 3H peak, dispersive mixing and diffusive loss of 3He perturb the age gradient near and below the 3H peak.

Measurement of differential cross section of D(3He,p)4He from 0.8 MeV to 3.6 MeV

Science.gov (United States)

Zhu, J. P.; Xiao, X.; Yan, S.; Gao, Y.; Xue, J. M.; Wang, Y. G.

2017-12-01

Precise knowledge of the nuclear reaction cross-section is crucial for nuclear reaction analysis methods and its applications. In order to apply nuclear reaction analysis methods to Plasma Facing Materials studies on 4.5 MV electrostatic accelerator at Peking University, differential cross-section for d(3He,p) α at several backward angles was measured with a relative error about ± 6.2 % , gives detailed information at the laboratory angle of 135° from 800 keV to 3600 keV, as well as a rough angular distribution from 130° to 160°.

Angular distribution measurements of {sup 6}Li(p,{alpha}){sup 3}He reaction at 140 keV proton energy using nuclear track detectors

Energy Technology Data Exchange (ETDEWEB)

Al-Jarallah, M.I. E-mail: mibrahim@kfupm.edu.sa; Naqvi, A.A.; Abu-Jarad, F.A.; Fazal-ur-Rehman; Durrani, S.M.A.; Kidwai, S

2001-06-01

Angular distributions of a {sup 6}Li(p,{alpha}) {sup 3}He reaction were measured at six angles for 140 keV proton energy using nuclear track detectors (NTDs). The measurements were carried out over 60 deg. -160 deg. lab. angles in 20 deg. increments using a scattering chamber of 80 deg. beam line of the 350 kV accelerator. A semiconductor silicon surface barrier (SSB) detector was placed at +160 deg. and was used as a monitor. The results have shown that the CR-39 detector has excellent capabilities to distinguish 1.4-2.7 MeV {alpha}+ {sup 3}He particles from the {sup 6}Li(p,{alpha}) {sup 3}He reaction and 8-9.4 MeV {alpha}-particles from the {sup 7}Li(p,{alpha}) {sup 4}He reaction through their track diameters. However, it was not possible to distinguish between the 2.3 MeV {sup 3}He ions and the 1.7 MeV {sup 4}He ions from the {sup 6}Li(p,{alpha}) {sup 3}He reaction from their track diameter measurements, but it was possible to differentiate between the two, from the darker contrast of the {sup 3}He particles caused by its deeper tracks as compared to those of {sup 4}He.

POLARIZED-LIGHT EMISSION IN KEV HE2++NA(3S) COLLISIONS

NARCIS (Netherlands)

BODUCH, P; VANBUCHEM, J; BLIEK, FW; HOEKSTRA, R; MORGENSTERN, R; OLSON, RE

1995-01-01

We investigated l and m-distributions of He II (n = 4) states formed during 2-13.3 keV amu(-1) He2+ + Na(3s) collisions by measuring profiles and the linear polarization of the He II (4 --> 3) emission. We found that at these energies capture into He+(4f) dominates over capture into other He+(4l)

Polarization transfer in the 3H(rvec p,rvec n)3He reaction and the 0- level in 4He

International Nuclear Information System (INIS)

Walston, J.R.; Gould, C.R.; Haase, D.G.; Raichle, B.W.; Seely, M.L.; Walston, J.R.; Keith, C.D.; Gould, C.R.; Haase, D.G.; Raichle, B.W.; Seely, M.L.; Tornow, W.; Wilburn, W.S.; Keith, C.D.; Tornow, W.; Wilburn, W.S.; Hoffmann, G.W.; Penttilae, S.I.

1998-01-01

Longitudinal polarization-transfer coefficients for the 3 H(rvec p,rvec n) 3 He reaction have been measured at zero degrees for proton energies of 1.3 endash 2.8 MeV. The results show a striking resonance behavior for energies corresponding to excitation of the 0 - level in 4 He at 21.0 MeV. In agreement with R-matrix calculations, the value approaches unity at 1.52 MeV, the peak of the resonance. Near this same energy, at 1.62 MeV, the transverse polarization-transfer coefficient was measured to be consistent with zero. copyright 1998 The American Physical Society

Tritium/3He measurements in young groundwater: Progress in applications to complex hydrogeological systems

Science.gov (United States)

Schlosser, Peter; Shapiro, Stephanie D.; Stute, Martin; Plummer, Niel

2000-01-01

Tritium/3He dating has been applied to many problems in groundwater hydrology including, for example, determination of circulation patterns, mean residence times, recharge rates, or bank infiltration. Here, we discuss recent progress in the application of the tritium/3He dating method to sites with complex hydrogeological settings. Specifically, we report on tritium/3He dating at sites with (a) river infiltration into the basaltic fractured rock aquifer of the Eastern Snake River Plain, and (b) river infiltration through sinkholes into the karstic limestone Upper Floridian aquifer near Valdosta, Georgia.Tritium/3He dating has been applied to many problems in groundwater hydrology including, for example, determination of circulation patterns, mean residence times, recharge rates, or bank infiltration. Here, we discuss recent progress in the application of the tritium/3He dating method to sites with complex hydrogeological settings. Specifically, we report on tritium/3He dating at sites with (a) river infiltration into the basaltic fractured rock aquifer of the Eastern Snake River Plain, and (b) river infiltration through sinkholes into the karstic limestone Upper Floridian aquifer near Valdosta, Georgia.

Test of ring, eye lens and whole body dosemeters for the dose quantity Hp(3) to be used in interventional radiology

Science.gov (United States)

Szumska, A.; Budzanowski, M.; Kopeć, R.

2017-11-01

In its statement on tissue reactions approved on 21st April 2011, the International Commission on Radiological Protection (ICRP, 2012) reviewed its recommendation concerning the equivalent dose limit for the eye lens and reduced the dose limits for occupationally exposed persons to 20 mSv in a year, averaged over defined periods of 5 years, with no single year exceeding 50 mSv. This limit was approved and written down in the new EURATOM (European Atomic Energy Community) directive 2013/59 and in the IAEA (International Atomic Energy Agency) BSS (Basic Safety Standard) of July 2014. For that reason, the necessity to monitor the eye lens may become more important than it was before. However, specially dedicated dosemeters for the dose quantity Hp(3) are using very rarely. Commonly use are only whole body personal dosemeters for the personal dose equivalent quantities Hp(10) worn on the trunk and ring dosemeters worn on finger to measure the quantity Hp(0.07). Therefore, in this work it was investigated whether dosemeters from routine use calibrated in terms of Hp(10) and Hp(0.07) and worn on thyroid collar and protective apron could deliver similar results like dedicated eye lens dosemeter worn close to the eyes. The results show that the best method if dedicated eye lens dosimeters is not used is to measure doses in terms of Hp(0.07) on the thyroid collar (Pearson product, r=0.85). Obtained results shows also importance of proper localization of eye lens dosimeter (close to the eye, from side of the X-ray source).

Measurement of Double-Polarization Asymmetries in the Quasielastic He3→(e → ,e'd ) Process

Science.gov (United States)

Mihovilovič, M.; Jin, G.; Long, E.; Zhang, Y.-W.; Allada, K.; Anderson, B.; Annand, J. R. M.; Averett, T.; Boeglin, W.; Bradshaw, P.; Camsonne, A.; Canan, M.; Cates, G. D.; Chen, C.; Chen, J. P.; Chudakov, E.; De Leo, R.; Deng, X.; Deltuva, A.; Deur, A.; Dutta, C.; El Fassi, L.; Flay, D.; Frullani, S.; Garibaldi, F.; Gao, H.; Gilad, S.; Gilman, R.; Glamazdin, O.; Golak, J.; Golge, S.; Gomez, J.; Hansen, O.; Higinbotham, D. W.; Holmstrom, T.; Huang, J.; Ibrahim, H.; de Jager, C. W.; Jensen, E.; Jiang, X.; Jones, M.; Kang, H.; Katich, J.; Khanal, H. P.; Kievsky, A.; King, P.; Korsch, W.; LeRose, J.; Lindgren, R.; Lu, H.-J.; Luo, W.; Marcucci, L. E.; Markowitz, P.; Meziane, M.; Michaels, R.; Moffit, B.; Monaghan, P.; Muangma, N.; Nanda, S.; Norum, B. E.; Pan, K.; Parno, D.; Piasetzky, E.; Posik, M.; Punjabi, V.; Puckett, A. J. R.; Qian, X.; Qiang, Y.; Qui, X.; Riordan, S.; Saha, A.; Sauer, P. U.; Sawatzky, B.; Schiavilla, R.; Schoenrock, B.; Shabestari, M.; Shahinyan, A.; Širca, S.; Skibiński, R.; John, J. St.; Subedi, R.; Sulkosky, V.; Tobias, W. A.; Tireman, W.; Urciuoli, G. M.; Viviani, M.; Wang, D.; Wang, K.; Wang, Y.; Watson, J.; Wojtsekhowski, B.; Witała, H.; Ye, Z.; Zhan, X.; Zhang, Y.; Zheng, X.; Zhao, B.; Zhu, L.; Jefferson Lab Hall A Collaboration

2014-12-01

We present a precise measurement of double-polarization asymmetries in the He3→(e → ,e'd ) reaction. This particular process is a uniquely sensitive probe of hadron dynamics in 3He and the structure of the underlying electromagnetic currents. The measurements have been performed in and around quasielastic kinematics at Q2=0.25 (GeV /c )2 for missing momenta up to 270 MeV /c . The asymmetries are in fair agreement with the state-of-the-art calculations in terms of their functional dependencies on pm and ω , but are systematically offset. Beyond the region of the quasielastic peak, the discrepancies become even more pronounced. Thus, our measurements have been able to reveal deficiencies in the most sophisticated calculations of the three-body nuclear system, and indicate that further refinement in the treatment of their two-and/or three-body dynamics is required.

The helium flux from the continents and ubiquity of low-3He/4He recycled crust and lithosphere

Science.gov (United States)

Day, James M. D.; Barry, Peter H.; Hilton, David R.; Burgess, Ray; Pearson, D. Graham; Taylor, Lawrence A.

2015-03-01

low-3He/4He values of these reservoirs and their distinctive compositions make them probable end-members to explain the compositions of some low-3He/4He OIB, and provide an explanation for the low-3He/4He measured in most HIMU lavas. Continental lithospheric mantle and recycled oceanic crust protoliths are not reservoirs for high-3He/4He and so alternative, volumetrically significant, He-rich reservoirs, such as less-degassed (lower?) mantle, are required to explain high-3He/4He signatures measured in some intraplate lavas. Recycling of oceanic crust represents a fundamental process for the generation of radiogenic noble gases in the mantle, and can therefore be used effectively as tracers for volatile recycling.

Calculations of static properties of spin-polarized 3He--4He mixtures

International Nuclear Information System (INIS)

Owers-Bradley, J.R.; Bowley, R.M.; Main, P.C.

1985-01-01

The theory of dilute mixtures of 3 He in 4 He that have been polarized by a strong magnetic field is developed. The interaction between the quasiparticles is taken to be constant, an approximation valid at low temperatures. The polarization of the mixture depends on the strength of the interaction. The internal energy, the specific heat, the osmotic pressure, and the velocity of second sound are also calculated. The specific heat is relatively insensitive to the interaction, but it does change significantly with magnetic field. The osmotic pressure is more sensitive to the effects of the interaction for some 3 He concentrations and temperatures. The velocity of second sound behaves qualitatively like the osmotic pressure. The measurement of these quantities as a function of temperature and magnetic field is discussed with a view to obtaining the strength of the interaction between quasiparticles

Experimental investigation and numerical simulation of 3He gas diffusion in simple geometries: implications for analytical models of 3He MR lung morphometry.

Science.gov (United States)

Parra-Robles, J; Ajraoui, S; Deppe, M H; Parnell, S R; Wild, J M

2010-06-01

Models of lung acinar geometry have been proposed to analytically describe the diffusion of (3)He in the lung (as measured with pulsed gradient spin echo (PGSE) methods) as a possible means of characterizing lung microstructure from measurement of the (3)He ADC. In this work, major limitations in these analytical models are highlighted in simple diffusion weighted experiments with (3)He in cylindrical models of known geometry. The findings are substantiated with numerical simulations based on the same geometry using finite difference representation of the Bloch-Torrey equation. The validity of the existing "cylinder model" is discussed in terms of the physical diffusion regimes experienced and the basic reliance of the cylinder model and other ADC-based approaches on a Gaussian diffusion behaviour is highlighted. The results presented here demonstrate that physical assumptions of the cylinder model are not valid for large diffusion gradient strengths (above approximately 15 mT/m), which are commonly used for (3)He ADC measurements in human lungs. (c) 2010 Elsevier Inc. All rights reserved.

Measurement of the Electrical Conductivity of He3 Plasma Induced by Neutron Irradiation

International Nuclear Information System (INIS)

Braun, J.; Nygaard, K.

1966-03-01

The conductivity of a He plasma created by the inelastic reaction with thermal neutrons: 3 He + n th -> 3 H + p + 0.76 MeV is studied as a function of neutron flux, gas temperature and gas density. Using reported values of the electron mobility the electron density is calculated from experimental conductivity values. Further, by accepting a reasonable value for the mean energy lost in creating one ion-pair, the recombination coefficient is estimated. The measurements performed so far cover temperatures between 300 - 1600 K and densities between 0.25 - 1 times the density at atmospheric pressure and 300 K. The neutron flux is varied between 10 10 - 10 11 n/cm 2 /s. As a sample of results achieved at 1600 K and the lowest density (corresponding to about atmospheric pressure) and the highest neutron flux the following values are obtained for the conductivity, the electron density and the recombination coefficient respectively: σ 0.2 S/m, n e 6x10 11 /cm 3 , α = 2xl0 -10 cm 3 /s. An extrapolation of data obtained shows that the concept of neutron induced conductivity should be attractive for MHD power generation

Particle transport in 3He-rich events: wave-particle interactions and particle anisotropy measurements

Directory of Open Access Journals (Sweden)

B. T. Tsurutani

2002-04-01

Full Text Available Energetic particles and MHD waves are studied using simultaneous ISEE-3 data to investigate particle propagation and scattering between the source near the Sun and 1 AU. 3 He-rich events are of particular interest because they are typically low intensity "scatter-free" events. The largest solar proton events are of interest because they have been postulated to generate their own waves through beam instabilities. For 3 He-rich events, simultaneous interplanetary magnetic spectra are measured. The intensity of the interplanetary "fossil" turbulence through which the particles have traversed is found to be at the "quiet" to "intermediate" level of IMF activity. Pitch angle scattering rates and the corresponding particle mean free paths lW - P are calculated using the measured wave intensities, polarizations, and k directions. The values of lW - P are found to be ~ 5 times less than the value of lHe , the latter derived from He intensity and anisotropy time profiles. It is demonstrated by computer simulation that scattering rates through a 90° pitch angle are lower than that of other pitch angles, and that this is a possible explanation for the discrepancy between the lW - P and lHe values. At this time the scattering mechanism(s is unknown. We suggest a means where a direct comparison between the two l values could be made. Computer simulations indicate that although scattering through 90° is lower, it still occurs. Possibilities are either large pitch angle scattering through resonant interactions, or particle mirroring off of field compression regions. The largest solar proton events are analyzed to investigate the possibilities of local wave generation at 1 AU. In accordance with the results of a previous calculation (Gary et al., 1985 of beam stability, proton beams at 1 AU are found to be marginally stable. No evidence for substantial wave amplitude was found. Locally generated waves, if present, were less than 10-3 nT 2 Hz-1 at the leading

Particle transport in 3He-rich events: wave-particle interactions and particle anisotropy measurements

Directory of Open Access Journals (Sweden)

T. Hada

Full Text Available Energetic particles and MHD waves are studied using simultaneous ISEE-3 data to investigate particle propagation and scattering between the source near the Sun and 1 AU. 3 He-rich events are of particular interest because they are typically low intensity "scatter-free" events. The largest solar proton events are of interest because they have been postulated to generate their own waves through beam instabilities. For 3 He-rich events, simultaneous interplanetary magnetic spectra are measured. The intensity of the interplanetary "fossil" turbulence through which the particles have traversed is found to be at the "quiet" to "intermediate" level of IMF activity. Pitch angle scattering rates and the corresponding particle mean free paths lW - P are calculated using the measured wave intensities, polarizations, and k directions. The values of lW - P are found to be ~ 5 times less than the value of lHe , the latter derived from He intensity and anisotropy time profiles. It is demonstrated by computer simulation that scattering rates through a 90° pitch angle are lower than that of other pitch angles, and that this is a possible explanation for the discrepancy between the lW - P and lHe values. At this time the scattering mechanism(s is unknown. We suggest a means where a direct comparison between the two l values could be made. Computer simulations indicate that although scattering through 90° is lower, it still occurs. Possibilities are either large pitch angle scattering through resonant interactions, or particle mirroring off of field compression regions. The largest solar proton events are analyzed to investigate the possibilities of local wave generation at 1 AU. In accordance with the results of a previous calculation (Gary et al., 1985 of beam stability, proton beams at 1 AU are found to be marginally stable. No evidence for substantial wave amplitude was found. Locally generated waves, if present, were less than 10-3 nT 2 Hz-1 at the leading

Proportionate Dwarfism in Mice Lacking Heterochromatin Protein 1 Binding Protein 3 (HP1BP3) Is Associated With Alterations in the Endocrine IGF-1 Pathway.

Science.gov (United States)

Garfinkel, Benjamin P; Arad, Shiri; Le, Phuong T; Bustin, Michael; Rosen, Clifford J; Gabet, Yankel; Orly, Joseph

2015-12-01

Heterochromatin protein 1 binding protein 3 (HP1BP3) is a recently described histone H1-related protein with roles in chromatin structure and transcriptional regulation. To explore the potential physiological role of HP1BP3, we have previously described an Hp1bp3(-/-) mouse model with reduced postnatal viability and growth. We now find that these mice are proportionate dwarfs, with reduction in body weight, body length, and organ weight. In addition to their small size, microcomputed tomography analysis showed that Hp1bp3(-/-) mice present a dramatic impairment of their bone development and structure. By 3 weeks of age, mice of both sexes have severely impaired cortical and trabecular bone, and these defects persist into adulthood and beyond. Primary cultures of both osteoblasts and osteoclasts from Hp1bp3(-/-) bone marrow and splenocytes, respectively, showed normal differentiation and function, strongly suggesting that the impaired bone accrual is due to noncell autonomous systemic cues in vivo. One major endocrine pathway regulating both body growth and bone acquisition is the IGF regulatory system, composed of IGF-1, the IGF receptors, and the IGF-binding proteins (IGFBPs). At 3 weeks of age, Hp1bp3(-/-) mice exhibited a 60% reduction in circulating IGF-1 and a 4-fold increase in the levels of IGFBP-1 and IGFBP-2. These alterations were reflected in similar changes in the hepatic transcripts of the Igf1, Igfbp1, and Igfbp2 genes. Collectively, these results suggest that HP1BP3 plays a key role in normal growth and bone development by regulating transcription of endocrine IGF-1 components.

A polarized solid {sup 3}He target for neutron transmission experiments

Energy Technology Data Exchange (ETDEWEB)

Keith, C.D. [North Carolina State Univ., Raleigh, NC (United States)]|[Triangle Universities Nuclear Laboratory, Durham, NC 27708-0308 (United States); Gould, C.R. [North Carolina State Univ., Raleigh, NC (United States)]|[Triangle Universities Nuclear Laboratory, Durham, NC 27708-0308 (United States); Haase, D.G. [North Carolina State Univ., Raleigh, NC (United States)]|[Triangle Universities Nuclear Laboratory, Durham, NC 27708-0308 (United States); Huffman, P.R. [Duke University, Durham, NC 27708-0308 (United States)]|[Triangle Universities Nuclear Laboratory, Durham, NC 27708-0308 (United States); Roberson, N.R. [Duke University, Durham, NC 27708-0308 (United States)]|[Triangle Universities Nuclear Laboratory, Durham, NC 27708-0308 (United States); Seely, M.L. [North Carolina State Univ., Raleigh, NC (United States)]|[Triangle Universities Nuclear Laboratory, Durham, NC 27708-0308 (United States); Tornow, W. [Duke University, Durham, NC 27708-0308 (United States)]|[Triangle Universities Nuclear Laboratory, Durham, NC 27708-0308 (United States); Wilburn, W.S. [Duke University, Durham, NC 27708-0308 (United States)]|[Triangle Universities Nuclear Laboratory, Durham, NC 27708-0308 (United States)

1995-04-01

We describe the construction and operation of a solid {sup 3}He polarized nuclear target which we have used for measurements of the spin dependence of the n-{sup 3}He interaction at MeV energies. The target, which contains 0.4 mole of {sup 3}He was polarized to 38% at 12 mK in a field of 7 T. The target is suitable for nuclear physics measurements which are insensitive to the large magnetic field and produce beam heating of tenths of microwatts.We discuss refinements and paths to improved solid {sup 3}He targets at higher polarizations and lower fields. ((orig.)).

The 3He Supply Problem

Energy Technology Data Exchange (ETDEWEB)

Kouzes, Richard T.

2009-05-01

One of the main uses for 3He is in gas proportional counters for neutron detection. Radiation portal monitors deployed for homeland security and non-proliferation use such detectors. Other uses of 3He are for research detectors, commercial instruments, well logging detectors, dilution refrigerators, for targets or cooling in nuclear research, and for basic research in condensed matter physics. The US supply of 3He comes almost entirely from the decay of tritium used in nuclear weapons by the US and Russia. A few other countries contribute a small amount to the world’s 3He supply. Due to the large increase in use of 3He for homeland security, the supply has dwindled, and can no longer meet the demand. This white paper reviews the problems of supply, utilization, and alternatives.

Proportionate Dwarfism in Mice Lacking Heterochromatin Protein 1 Binding Protein 3 (HP1BP3) Is Associated With Alterations in the Endocrine IGF-1 Pathway

OpenAIRE

Garfinkel, Benjamin P.; Arad, Shiri; Le, Phuong T.; Bustin, Michael; Rosen, Clifford J.; Gabet, Yankel; Orly, Joseph

2015-01-01

Heterochromatin protein 1 binding protein 3 (HP1BP3) is a recently described histone H1-related protein with roles in chromatin structure and transcriptional regulation. To explore the potential physiological role of HP1BP3, we have previously described an Hp1bp3?/? mouse model with reduced postnatal viability and growth. We now find that these mice are proportionate dwarfs, with reduction in body weight, body length, and organ weight. In addition to their small size, microcomputed tomography...

Development of polarized {sup 3}He filter for polarized neutron experiment

Energy Technology Data Exchange (ETDEWEB)

Sakai, K.; Sato, H.; Yoshimi, A.; Asahi, K. [Tokyo Inst. of Tech. (Japan). Faculty of Science; Masuda, Y.; Muto, S.; Ishimoto, S.; Morimoto, K.

1996-08-01

A high-pressure polarized {sup 3}He gas cell, pumped with two diode lasers, has been developed at KEK for use as a polarizer and a spin analyzer for low energy neutrons. The polarization attained of {sup 3}He was determined through the measurement of the transmission of the unpolarized neutrons through the {sup 3}He cell. So far we obtained P{sub He}=18% at 10 atm and P{sub He}=12% at 20 atm. (author)

Dynamics of phase-separated 3He-4He films

International Nuclear Information System (INIS)

Kurihara, Susumu

1982-01-01

A froehlich-type Hamiltonian is derived for third sound and 3 He quasi particles in phase-separated double layer of superfluid 4 He and normal 3 He liquid. It is stressed that our system is unique and valuable in that characteristic parameters can be varied in a wide range, simply by adjusting the film thickness. The effect of fermion-boson coupling on the velocity and damping of the third sound is examined. It is predicted that a rather drastic change in the third sound spectrum will occur when the Fermi velocity of 3 He system and the third sound velocity are nearly the same. It is pointed out that the system under consideration may show a variety of interesting phenomena, in addition to the softening of the third sound. (author)

Dielectric Constant Measurements of Solid 4He

Science.gov (United States)

Yin, L.; Xia, J. S.; Huan, C.; Sullivan, N. S.; Chan, M. H. W.

2011-03-01

Careful measurements of the dielectric properties of solid 4He have been carried out down to 35 mK, considerably lower than the temperature range of previous studies. The sample was prepared from high purity gas with 3He concentrations of the order of 200 ppb and were formed by the blocked capillary method. The molar volume of the sample was 20.30 cm3. The dielectric constant of the samples was found to be independent of temperature down to 120 mK before showing a continuous increase with decreasing temperature and saturating below 50 mK. The total increase in ɛ is 2 parts in 10-5. The temperature dependence of ɛ mimics the increase in the resonant frequency found in the torsional oscillator studies and also the increase found in the shear modulus measurements.

Annihilation of antiprotons at rest in 3He and 4He

International Nuclear Information System (INIS)

Balestra, F.; Bossolasco, S.; Bussa, M.P.; Busso, L.; Fava, L.; Ferrero, L.; Panzieri, D.; Piragino, G.; Tosello, F.; Bendiscioli, G.; Rotondi, R.; Salvini, P.; Zenoni, A.; Batusov, Y.A.; Bunyatov, S.A.; Falomkin, I.V.; Nichitiu, F.; Pontecorvo, G.B.; Sapozhnikov, M.G.; Tretyak, V.I.; Guaraldo, C.; Maggiora, A.; Haatuft, A.; Halsteinslid, A.; Myklebost, K.; Olsen, J.M.; Breivik, F.O.; Jacobsen, T.; Sorensen, S.O.

1987-01-01

At LEAR of CERN the annihilation of antiprotons stopping in 3 He and 4 He filling a self shunted streamer chamber in magnetic field has been studied. The relative probabilities of π - production in anti p 3 He and anti p 4 He annihilation events have been obtained. The ratio between the anti p annihilation probability on the neutron and on the proton for 3 He and 4 He has been deduced to be about half the value obtained for 2 H in bubble chamber experiments. The analysis of the results shows this difference cannot be ascribed only to the pion final state interaction or to the shadow effect of the nucleons in the nuclei. 9 refs.; 2 figs

Study of the sup 3 H( sup 3 H, 2n) sup 4 He and sup 3 He( sup 3 He, 2p) sup 4 He reactions in the framework of three-cluster microscopic model

CERN Document Server

Vasilevsky, V S; Arickx, F; Broeckhove, J

2002-01-01

The reactions sup 3 H( sup 3 H, 2n) sup 4 He and sup 3 He( sup 3 He, 2p) sup 4 He are investigated within a fully microscopic cluster model featuring a three-cluster exit channel. A Hyperspherical Harmonics basis is used to describe the three-cluster continuum. The resulting astrophysical s-factor of both reactions is in good agreement with experimental data. Analysis of the low-energy scattering parameters reveals no evidence for a hidden resonance state would increase the cross-section of the reactions, and would help to resolve the solar neutrino problem.

Spectroscopic factors measurements in the s,d and f,p shells below and above the Coulomb barrier by (3He,d) reactions

International Nuclear Information System (INIS)

Baghdadi, Ahmed.

1974-01-01

The overlap of t and d or 3 He and d wave functions may be measured by one neutron transfer in (d,t) or one proton transfer in ( 3 He,d). The measurement of the resulting normalization constant has been performed in subcoulombic conditions in the case of 58 Ni( 3 He,d) 59 Cu and 60 Ni( 3 He,d) 61 Cu leading to the first 3/2 - and 1/2 - states with a position sensitive detector in a Buechner spectrograph. The result: D 2 =2.7+-0.2 10 4 MeV 2 fm 3 is in agreement with the D 2 measurement for (t,d) reactions [3.1+-0.2 10 4 MeV 2 fm 3 ] and with the theoretical value proposed by L.J.B. Goldfarg and coworkers. This result was used for a determination of the spectroscopic factors of the 1.379MeV 3/2 - state, the 1.507MeV 1/2 - state and the 1.758MeV 3/2 - state in 57 Co. The subcoulombic approximation is also shown to be valid even in the case of (d,p) reactions, by the measurement of angular distributions and excitation curves of 60 Ni(d,p) reactions leading to the excited states at 4.760MeV (l=2) and 4.907MeV (l=0). In the second part, some spectroscopic factors in the s-d shell were measured by ( 3 He,d) reactions at MP Tandem energies. In the case of 27 Al( 3 He,d) 28 Si (states at 4.62, 6.88, 6.89, 9.32 and 0.38MeV) the normalization constant D 0 2 (deduced from the subcoulombic D 2 value) together with the first order finite range approximation leads to spectroscopic factors in good agreement with Wildenthal theoretical results. For 28 Si( 3 He,d) 29 p however, the values are too high compared to 29 Si. The conclusion is that it is better to use the DWBA treatment at subcoulombic energies everytime the experimental conditions may be fulfilled [fr

Analysis of the reaction 3He + p → p + p + d at 2,5 GeV/c 3He nucleus momentum

International Nuclear Information System (INIS)

Blinov, A.V.; Chuvilo, I.V.; Drobot, V.V.

1984-01-01

The experimental data on the reaction 3 He+p → p+p+d obtained by the exposition of an 80 cm liquid hydrogen bubble chamber to the 3 He nucleus beam at 2.5 GeV/c momentum are considered. The angular, momentum and invariant mass distributions, which have been measured, are compared with theoretical calculations performed using the pole model. On the whole a satisfactory agreement between theoretical and experimental data is found in the kinematical region, where pd- rescattering effects are negligible. It is concluded, that 3 He nuclear wave function calculated by means of nonrelativistic potential models falls too sharply with the spectator momenta as compared with the data

Probing HeII Reionization at z>3.5 with Resolved HeII Lyman Alpha Forest Spectra

Science.gov (United States)

Worseck, Gabor

2017-08-01

The advent of GALEX and COS have revolutionized our view of HeII reionization, the final major phase transition of the intergalactic medium. COS spectra of the HeII Lyman alpha forest have confirmed with high confidence the high HeII transmission that signifies the completion of HeII reionization at z 2.7. However, the handful of z>3.5 quasars observed to date show a set of HeII transmission 'spikes' and larger regions with non-zero transmission that suggest HeII reionization was well underway by z=4. This is in striking conflict with predictions from state-of-the-art radiative transfer simulations of a HeII reionization driven by bright quasars. Explaining these measurements may require either faint quasars or more exotic sources of hard photons at z>4, with concomitant implications for HI reionization. However, many of the observed spikes are unresolved in G140L spectra and are significantly impacted by Poisson noise. Current data cannot reliably probe the ionization state of helium at z>3.5.We request 41 orbits to obtain science-grade G130M spectra of the two UV-brightest HeII-transmitting QSOs at z>3.5 to confirm and resolve their HeII transmission spikes as an unequivocal test of early HeII reionization. These spectra are complemented by recently obtained data from 8m telescopes: (1) Echelle spectra of the coeval HI Lya forest to map the underlying density field that modulates the HeII absorption, and (2) Our dedicated survey for foreground QSOs that may source the HeII transmission. Our recent HST programs revealed the only two viable targets to resolve the z>3.5 HeII Lyman alpha forest, and to conclusively solve this riddle.

Effect of Mutations on HP Lattice Proteins

Science.gov (United States)

Shi, Guangjie; Vogel, Thomas; Landau, David; Li, Ying; Wüst, Thomas

2013-03-01

Using Wang-Landau sampling with approriate trial moves[2], we investigate the effect of different types of mutations on lattice proteins in the HP model. While exact studies have been carried out for short HP proteins[3], the systems we investigate are of much larger size and hence not accessible for exact enumerations. Based on the estimated density of states, we systematically analyse the changes in structure and degeneracy of ground states of particular proteins and measure thermodynamic quantities like the stability of ground states and the specific heat, for example. Both, neutral mutations, which do not change the structure and stability of ground states, as well as critical mutations, which do change the thermodynamic behavior qualitatively, have been observed. Research supported by NSF

Study of the {sup 6}Li + p → {sup 3}He + {sup 4}He reaction in inverse kinematics

Energy Technology Data Exchange (ETDEWEB)

Betsou, C.; Pakou, A.; Aslanoglou, X.; Nicolis, N.G.; Sgouros, O.; Soukeras, V. [The University of Ioannina, Department of Physics and HINP, Ioannina (Greece); Cappuzzello, F. [Laboratori Nazionali del Sud, INFN, Catania (Italy); Universita di Catania, Dipartimento di Fisica e Astronomia, Catania (Italy); Acosta, L. [Universidad Nacional Autonoma de Mexico, Instituto de Fisica, Mexico Distrito Federal (Mexico); INFN, Catania (Italy); Agodi, C.; Carbone, D.; Cavallaro, M.; Di Pietro, A.; Fernandez-Garcia, J.P.; Figuera, P.; Fisichella, M. [Laboratori Nazionali del Sud, INFN, Catania (Italy); Foti, A. [Universita di Catania, Dipartimento di Fisica e Astronomia, Catania (Italy); INFN, Catania (Italy); Keeley, N. [National Centre for Nuclear Research, Otwock (Poland); Marquinez-Duran, G.; Martel, I. [Universidad de Huelva, Departamento de Fisica Aplicada, Huelva (Spain); Mazzocco, M.; Strano, E.; Torresi, D. [Universita di Padova, Departimento di Fisica e Astronomia, Padova (Italy); INFN, Padova (Italy); Pierroutsakou, D. [INFN, Napoli (Italy); Rusek, K. [University of Warsaw, Heavy Ion Laboratory, Warsaw (Poland); Stiliaris, E. [University of Athens, Institute of Accelerating Systems and Applications and Department of Physics, Athens (Greece)

2015-07-15

Angular distribution measurements were performed for the {sup 6}Li + p → {sup 3}He + {sup 4}He reaction in inverse kinematics at incident energies of 2.7, 3.3, 4.2 and 4.8 MeV/u. The detection of both recoils ({sup 3}He and {sup 4}He) over the laboratory angle range θ{sub lab} = 16 {sup circle} to 34 {sup circle} allowed the determination of the angular distribution over a wide angular range in the center-of-mass frame (θ{sub c.m.} ∝ 40 {sup circle} to 140 {sup circle}). The results clarify inconsistencies between existing data sets and are consistent with compound nucleus model calculations. (orig.)

Δ excitation in 3He and 4He by photons

International Nuclear Information System (INIS)

Maruyama, Koichi.

1993-06-01

The use of the 3 He and 4 He photodisintegration reactions in the study of the excitation, propagation, and decay of the Δ (1232) in these nuclei is proposed. By using the data obtained with TAGX for both photon absorption on neutron-proton pairs and complete photodisintegration, we find no compelling evidence for the change of the Δ property in the 3 He and 4 He nuclei. It is also proposed to use nuclear photodisintegration in the search for the excitation of the higher-mass nucleon resonances whose absence in the total photon-absorption cross sections in nuclei is reported recently. (author)

3He and chlorofluorocarbons (CFC) in the Southern Ocean

International Nuclear Information System (INIS)

Jean-Baptiste, P.; Jamous, D.; Mantisi, F.; Memery, L.; Universite Paris 6

1991-01-01

The distribution of 3 He across the Southern Ocean is depicted on the basis of a meridional section between Antarctica and South Africa measured during the INDIGO-3 survey (1988). A core of δ 3 He values above 10% is observed south of the Polar Front, associated with very low CFC concentrations. This 3 He enriched layer is documented from the GEOSECS and INDIGO 3 He data in the Southern Ocean. It is found at a density level around θ σ =27.8 in all the waters close to Antarctica (i.e. south of 50 degS). Its zonal distribution suggests that it is likely that it originates from the central/eastern Pacific. Hence, it provides an indication of the deep Pacific waters in the Antarctic Circumpolar Current, which are not easily detectable from the standard hydrographic parameters. (author). 19 refs.; 8 figs

A method to quantify tritium inside waste drums: He{sup 3} ingrowth method

Energy Technology Data Exchange (ETDEWEB)

Godot, A.; Lepeytre, C.; Hubinois, J.C. [CEA Valduc, Dept. Traitement Materiaux Nucleaires, Service Analyses- Dechets, Lab. Chimie Analytique, 21 - Is-sur-Tille (France); Arseguel, A.; Daclin, J.P.; Douche, C. [CEA Valduc, Dept. Traitement Materiaux Nucleaires, Service Analyses- Dechets, Lab. de Gestion des Dechets Trities, 21 - Is-sur-Tille (France)

2008-07-15

This method enables an indirect, non intrusive and non destructive measurement of the Tritium activity in wastes drums. The amount of tritium enclosed inside a wastes drum can be determined by the measurement of the leak rate of {sup 3}He of this latter. The simulation predicts that a few months are necessary for establishing the equilibrium between the {sup 3}He production inside the drum and the {sup 3}He drum leak. In practice, after one year of storage, sampling {sup 3}He outside the drum can be realized by the mean of a confining chamber that collect the {sup 3}He outflow. The apparatus, the experimental procedure and the calculation of tritium activity from mass spectrometric {sup 3}He measurements are detailed. The industrial device based on a confinement cell and the automated process to measure the {sup 3}He amount at the initial time and after the confinement time is described. Firstly, reference drums containing a certified tritium activity (HTO) in addition to organic materials have been measured to qualify the method and to evaluate its performances. Secondly, tritium activity of organic wastes drums issued from the storage building in Valduc have been determined. Results of the qualification and optimised values of the experimental parameters are reported in order to determine the performances of this industrial device. As a conclusion, the apparatus enables the measurement of an activity as low as 1 GBq of tritium in a 200 liters drum containing organic wastes. (authors)

Positive ion mobilities in normal liquid 3He at ultralow temperatures

International Nuclear Information System (INIS)

Alexander, P.W.

1978-11-01

The mobility has been measured of positive ions in liquid 3 he in the range 2.5 mK 3 sub(m)/sup(V) 5 sub(m)/sup(V). The effects of 500 p.p.m. 4 He in the 3 He were investigated. It was found that, at low temperatures, several stable ion species could be produced for 3 He pressures of 23 bar and above and, between 25 mK and 60 mK, time dependent conversion from one species of ion to another was observed at all pressures. The creation mechanism, mobility and stability of multiple positive ions were studied. Possible explanations of the phenomena are discussed. The measured drift field dependence of mobility is used to test the quasiparticle scattering model assumed for the liquid. (U.K.)

Study of the multiple exchange frequencies in bcc 3He by thermodynamic measurements

International Nuclear Information System (INIS)

Bernier, M.; Suaudeau, E.; Roger, M.

1987-08-01

To study the multiple exchange hamiltonian of solid 3 He we measured the contribution of the spin exchange to the pressure of bcc solid in various magnetic fields (O≤ H≤ 7.5T). Due to the nature of the atomic exchange of a fermion system this contribution is a strong function of the spin polarization. The characteristic frequencies of the exchange hamiltonian are obtained by fitting the pressure measurements with the results of a statistical calculation using a high temperature series expansion of the hamiltonian in a temperature range where both the magnetic effect is significant and the expansion converges (7mK < T < 30mK). We discuss the results obtained for two molar volumes

The relation between temperature and concentration gradients in superfluid sup 3 He- sup 4 He solutions

CERN Document Server

Zadorozhko, A A; Rudavskij, E Y; Chagovets, V K; Sheshin, G A

2003-01-01

The temperature and concentration gradients nabla T and nabla x in a superfluid sup 3 He- sup 4 He mixture with an initial concentration 9,8 % of sup 3 He are measured in a temperature range 70-500 mK. The gradients are produced by a steady thermal flow with heating from below. It is shown that the value of nabla x/nabla T observed in the experiment is in good agreement with the theoretical model derived from the temperature and concentration dependences of osmotic pressure. The experimental data permitted us to obtain a thermal diffusion ratio of the solution responsible for the thermal diffusion coefficient.

Surface study of liquid 3He using surface state electrons

International Nuclear Information System (INIS)

Shirahama, K.; Ito, S.; Suto, H.; Kono, K.

1995-01-01

We have measured the mobility of surface state electrons (SSE) on liquid 3 He, μ 3 , aiming to study the elementary surface excitations of the Fermi liquid. A gradual increase of μ 3 below 300 mK is attributed to the scattering of electrons by ripplons. Ripplons do exist in 3 He down to 100 mK. We observe an abrupt decrease of μ 3 , due to the transition to the Wigner solid (WS). The dependences of the WS conductivity and mobility on temperature and magnetic field differ from the SSE behavior on liquid 4 He

Differential osmotic pressure measurements of the concentration susceptibility of liquid 3He/4He mixtures near the lambda curve and tricritical point

International Nuclear Information System (INIS)

Gearhart, C.A. Jr.; Zimmermann, W. Jr.

1979-01-01

Values of the concentration susceptibility (partial x/partial Δ)/sub T/,P of liquid 3 He/ 4 He mixtures have been determined near the lambda curve and tricritical point from measurements of the differential osmotic pressure as a function of temperature T at four values of the 3 He mole fraction, x = 0.594, x = 0.644, x = 0.680, and x = 0.706. Here Δ = μ 3 - μ 4 is the difference between molar chemical potentials and P is the pressure. Our results for the two values of x less than the tricritical value x/sub t/ = 0.675 show pronounced peaks at the lambda transition. For 3 x 10 -4 -2 , where t equals [T - T/sub lambda/(x)]/T/sub lambda/(x), these peaks may be characterized both above and below the transition by the form (A/sub plus-or-minus//α/sub plus-or-minus/) (vertical-bart vertical-bar/sup -alpha/ +- - 1) + B/sub plus-or-minus/, with exponents α/sub plus-or-minus/ lying in the range from approx. 0.0 to approx. 0.2. Except perhaps for x -1 [T-T/sub t//T/sub t/)/vertical-barx-x/sub t//x/sub t/vertical-bar], where f and Ψ are functions determined by experiment and T/sub t/ = 0.867 K is the tricritical value of T. With the aid of this scaling relationship, the behavior of (partialx/partialΔ)/sub T/,P along curves of constant Δ near the lambda curve has been constucted from our data at constant x

Terrestrial cosmogenic 3He: where are we 30 years after its discovery?

Science.gov (United States)

Blard, Pierre-Henri; Pik, Raphaël; Farley, Kenneth A.; Lavé, Jérôme; Marrocchi, Yves

2016-04-01

It is now 30 years since cosmogenic 3He has been detected for the first time in a terrestrial sample (Kurz, 1986). 3He is now a widely used geochemical tool in many fields of Earth sciences: volcanology, tectonics, paleoclimatology. 3He has the advantage to have a high "production rate" to "detection limit" ratio, allowing surfaces as young as hundred of years to be dated. Although its nuclear stability implies several limitations, it moreover represents a useful alternative to 10Be in mafic environments. This contribution is a review of the progresses that have been accomplished since this discovery, and discuss strategies to improve both the accuracy and the precision of this geochronometer. 1) Measurement of cosmogenic 3He Correction of magmatic 3He. To estimate the non-cosmogenic magmatic 3He, Kurz (1986) invented a two steps method involving crushing of phenocrysts (to analyze the isotopic ratio of the magmatic component), followed by a subsequent melting of the sample, to extract the remaining components, including the cosmogenic 3He: 3Hec = 3Hemelt -4Hemelt x (3He/4He)magmatic (1) Several studies suggested that the preliminary crushing may induce a loss of cosmogenic 3He (Hilton et al., 1993; Yokochi et al., 2005; Blard et al., 2006), implying an underestimate of the cosmogenic 3He measurement. However, subsequent work did not replicate these observations (Blard et al., 2008; Goerhing et al., 2010), suggesting an influence of the used apparatus. An isochron method (by directly melting several phenocrysts aliquots) is an alternative to avoid the preliminary crushing step (Blard and Pik, 2008). Atmospheric contamination. Protin et al. (in press) provides robust evidences for a large and irreversible contamination of atmospheric helium on silicate surfaces. This unexpected behavior may reconcile the contrasted observations about the amplitude of crushing loss. This undesirable atmospheric contamination is negligible if grain fractions smaller than 150 mm are

Regional and temporal variations in CO2/3He, 3He/4He and δ13C along the North Anatolian Fault Zone, Turkey

International Nuclear Information System (INIS)

Leeuw, G.A.M. de; Hilton, D.R.; Guelec, N.; Mutlu, H.

2010-01-01

New He and C relative abundance, isotope and concentration results from nine geothermal locations situated along an 800-km transect of the North Anatolian Fault Zone (NAFZ), Turkey, that were monitored during the period November 2001-November 2004, are reported. The geothermal waters were collected every 3-6 months to study possible links between temporal geochemical variations and seismic activity along the NAFZ. At the nine sample locations, the He isotope ratios range from 0.24 to 2.3R A , δ 13 C values range from -4.5 to +5.8 per mille, and CO 2 / 3 He ratios range from 5 x 10 9 to 5 x 10 14 . The following geochemical observations are noted: (1) the highest 3 He/ 4 He ratios are found near the Galatean volcanic region, in the central section of the NAFZ, (2) at each of the nine sample locations, the 3 He/ 4 He ratios are generally constant; however, CO 2 / 3 He ratios and He contents both show one order of magnitude variability, and δ 13 C values show up to ∼4 per mille variability, and (3) at all locations (except Resadiye), δ 13 C values show positive correlations with CO 2 contents. The results indicate that at least three processes are necessary to account for the geochemical variations: (1) binary mixing between crustal and mantle-derived volatiles can explain the general characteristics of 3 He/ 4 He ratios, δ 13 C values, and CO 2 / 3 He ratios at the nine sample locations; (2) preferential degassing of He from the geothermal waters is responsible for variations in CO 2 / 3 He values and He contents at each sample location; and (3) CO 2 dissolution followed by calcite precipitation is responsible for variations in CO 2 contents and δ 13 C values at most locations. For each of the geochemical parameters, anomalies are defined in the temporal record by values that fall outside two standard deviations of average values at each specific location. Geochemical anomalies that may be related to seismic activity are recorded on June 28, 2004 at Yalova

Towards accurate T-3He Q-value

Energy Technology Data Exchange (ETDEWEB)

Eronen, Tommi; Hoecker, Martin; Ketter, Jochen; Streubel, Sebastian; Blaum, Klaus [Max-Planck Institut fuer Kernphysik, Heidelberg (Germany); Van Dyck, Robert S. Jr. [Department of Physics, University of Washington, Seattle, WA (United States)

2013-07-01

Great efforts have been put forward to determine the neutrino mass from tritium β decay. The most prominent experimental setup, KATRIN, is expected to deliver an upper limit to the neutrino mass that is one order of magnitude more stringent than the current value by measuring the endpoint and the shape of the β spectrum of the tritium decay. The endpoint energy (assuming zero neutrino mass) can also be deduced from the Q-value of the decay by measuring the mass difference of tritium and the daughter {sup 3}He using high-resolution mass spectrometry. Such a measurement would give an excellent, independent calibration point for the KATRIN experiment to deduce its systematics. Our mass-difference measurement utilizes the Tritium- Helium double Penning trap (THe-Trap) setup. Based on the anharmonic cyclotron frequency determination method pioneered at the University of Washington, Seattle, precision at the level of 1 part in 10{sup 11} in the T/{sup 3}He mass ratio is expected. In this contribution, I describe the motivation, the principle, current status, and expectations of the experiment.

Towards the observation of the magnetic structure of solid 3He

International Nuclear Information System (INIS)

Rufin, D.

1982-03-01

Experiments involving neutron scattering by 3 He for which thermalization problems have been solved, along with the development of novel measurement techniques (density, magnetization, temperature) by polarized neutron transmission, crystallization experiments with 3 He and 4 He: a single crystal of helium have been obtained within a sintered metal in which the pore size is less than a micron are presented [fr

Results on Double-polarization Asymmetries in Quasielastic Scattering from Polarized 3He

Directory of Open Access Journals (Sweden)

Sulkosky Vincent A.

2016-01-01

Full Text Available The 3He nucleus has become extremely important in the investigation of the neutron’s spin structure. When polarized, 3He acts as an effective polarized neutron target and hence facilitates our understanding of the neutron’s internal structure. However, to be used in this manner, our understanding of the internal structure of 3He is of extreme importance. As the precision of experiments has improved, the extraction of polarized neutron information from 3He leads to an ever larger share of the systematic uncertainty for these experiments. In these proceedings, I present a precise measurement of beam-target asymmetries in the He→3(e→ ,e′d${}^3\\overrightarrow {He} (\\vec e,e'd$ and He→3(e→,e′p${}^3\\overrightarrow {He} (\\vec e,e'p$ reactions. The former process is a uniquely sensitive probe of hadron dynamics in 3He and the structure of the underlying electromagnetic currents. The measurements have been performed around the quasi-elastic peak at Q2 = 0.25 (GeV/c2 and 0.35 (GeV/c2 for recoil momenta up to 270 MeV/c. The experimental apparatus, analysis and results were presented together with a comparison to state-of-the art Faddeev calculations.

Analysis of HP1α regulation in human breast cancer cells

DEFF Research Database (Denmark)

Thomsen, Rune; Christensen, Dennis B; Rosborg, Sanne

2011-01-01

The three mammalian HP1 proteins, HP1α/CBX5, HP1β/CBX1, and HPγ/CBX3, are involved in chromatin packing and gene regulation. The HP1α protein is down-regulated in invasive compared to non-invasive breast cancer cells and HP1α is a suppressor of cell migration and invasion. In this report, we...... examined the background for HP1α protein down-regulation in invasive breast cancer cells. We identified a strict correlation between HP1α down-regulation at the protein level and the mRNA level. The HP1α mRNA down-regulation in invasive cancer cells was not caused by mRNA destabilization. Chromatin...... immunoprecipitation analysis of the HP1α gene showed a decrease in the histone mark for transcriptional activity H3-K36 tri-methylation and RNA polymerase II in invasive breast cancer cells which correlated with a decreased abundance of basal transcription factors at the HP1α promoter. E2F transcription factors...

Measuring the Neutron and 3He Spin Structure at Low Q2

International Nuclear Information System (INIS)

Vince Sulkosky

2005-01-01

The spin structure of the nucleon has been of great interest over the past few decades. Sum rules, including the Gerasimov-Drell-Hearn (GDH), and moments of the spin structure functions are powerful tools for understanding nucleon structure. The GDH sum rule, originally derived for real photon absorption, has been generalized to nonzero Q 2 . The goal of Jefferson Lab experiment E97-110 is to perform a precise measurement of the Q 2 dependence of the generalized GDH integral and of the moments of the neutron and 3 He spin structure functions between 0.02 and 0.3 GeV 2 . This Q 2 range will allow us to test predictions of Chiral Perturbation Theory, and verify the GDH sum rule by extrapolating the integral to the real photon point. The measurement will also contribute to the understanding of nucleon resonances. The data have been taken in Hall A using a high resolution spectrometer with the addition of a septum magnet, which allowed us to access the low Q 2 region. The analysis's status, prospects and impact will be discussed

Measurement of the Electrical Conductivity of He{sup 3} Plasma Induced by Neutron Irradiation

Energy Technology Data Exchange (ETDEWEB)

Braun, J; Nygaard, K

1966-03-15

The conductivity of a He plasma created by the inelastic reaction with thermal neutrons: {sup 3}He + n{sub th} -> {sup 3}H + p + 0.76 MeV is studied as a function of neutron flux, gas temperature and gas density. Using reported values of the electron mobility the electron density is calculated from experimental conductivity values. Further, by accepting a reasonable value for the mean energy lost in creating one ion-pair, the recombination coefficient is estimated. The measurements performed so far cover temperatures between 300 - 1600 K and densities between 0.25 - 1 times the density at atmospheric pressure and 300 K. The neutron flux is varied between 10{sup 10} - 10{sup 11} n/cm{sup 2}/s. As a sample of results achieved at 1600 K and the lowest density (corresponding to about atmospheric pressure) and the highest neutron flux the following values are obtained for the conductivity, the electron density and the recombination coefficient respectively: {sigma} 0.2 S/m, n{sub e} 6x10{sup 11}/cm{sup 3}, {alpha} = 2xl0{sup -10} cm{sup 3}/s. An extrapolation of data obtained shows that the concept of neutron induced conductivity should be attractive for MHD power generation.

Effective interactions in dilute mixtures of 3He in 4He

International Nuclear Information System (INIS)

Hsu, W.; Pines, D.

1985-01-01

Nonlocal pseudopotentials which describe the effective interaction between 3 He quasiparticles, and between these quasiparticles and the background 4 He liquid, are obtained as a function of concentration and pressure by generalizing the Aldrich--Pines pseudopotentials for pure 3 He and 4 He to dilute mixtures. The hierarchy of physical effects which determine these pseudopotentials is established. Interaction-induced short-range correlations are the dominant physical feature; next in order of importance is the greater zero point motion associated with the replacement of a 4 He atom by a 3 He atom, while spin-duced ''Pauli principle'' correlations play a significantly smaller, albeit still important role. We find a consistent trend in the change of the effective direct quasiparticle interactions with increasing concentration, and show how the Aldrich-Pines pseudopotentials for pure 3 He quasiparticles represent a natural extension of our results for dilute mixtures. Our calculated nonlocal pseudopotential for 3 He quasiparticles is qualitatively similar to that proposed by Bardeen, Baym, and Pines; it changes sign at somewhat lower momentum transfers than the BBP result, varies little with concentration, and provides a physical basis for understanding the BBP result. The effective interaction between quasiparticles of parallel spin, here determined for the first time, is essentially repulsive in the very dilute limit; as the concentration increases, it becomes increasingly attractive at low momentum transfers, and resembles closely that between antiparallel spin quasiparticles at 5% concentration. The concentration-dependent transport properties calculated from these pseudopotentials (which involve only one phenomenological parameter) are in good agreement with experiment at saturated vapor pressure (SVP), 10 atm, and 20 atm

Spin-polarized electron capture for the Na+3He2+ system at a 3He2+ impact energy of 5.33--9.33 keV/amu

International Nuclear Information System (INIS)

Tanaka, M.; Shimakura, N.; Ohshima, T.; Katori, K.; Fujiwara, M.; Ogata, H.; Kondo, M.

1994-01-01

3 He + atomic polarizations following the spin-polarized electron capture process for the N rvec a(3s)+ 3 He 2+ system were measured at 3 He 2+ impact energies from 5.33 to 9.33 keV/amu. The magnitude of the 3 He + atomic polarizations was deduced from the 3 He + nuclear polarization measured by means of beam-foil spectroscopy. The observed polarization transfer coefficient P T defined by the ratio of the 3 He + atomic polarization to the sodium one showed a pronounced reduction from unity, which was qualitatively explained by the prediction of a simple cascade photon decay model. Evidence for a further reduction of P T from the above model and a possible impact energy dependence of P T suggested an excessive depolarization due to the presence of the collision alignment parameter A 0 col of 3 He + formed by the electron capture process. In order to see this more closely, the observed P T 's were examined theoretically using the semiclassical impact parameter method, in which an 18-state molecular expansion was employed, and atomic-type electron translation effects were rigorously taken into account. Ensuring that both the absolute values and the impact energy dependence of the observed capture cross sections were remarkably well reproduced by the calculations in which the states up to 4f in 3 He + were introduced, it was demonstrated that the calculated results for P T qualitatively reproduced not only the absolute values of the observed P T 's but also their gentle decrease with increasing impact energy. Production of nuclear polarizations resulting from the polarized electron capture processes between multicharged heavy ions and alkaline-earth-metal atoms is an example of one use of the future project of universal polarized heavy-ion sources

Dissipation of flow in superfluid 3He-A

International Nuclear Information System (INIS)

Paalanen, M.A.; Osheroff, D.D.

1980-01-01

The first direct measurements of the dissipation due to flow are performed and the effects of that flow on the NMR properties of 3 He-A are studied. A temperature-independent critical velocity v/sub c/=0.52 mm/s is observed, above which a pressure difference proportional to v/sub s/-v/sub c/ developes across our flow orifice. simultaneously, the NMR frequency in 3 He-A is lowered by an amount also proportional to v/sub s/-v/sub c/, in contrast to current theoretical predictions

Quasi-free and sequential processes in the 9Be(3He,αα)4He reaction at 2,8 MeV

International Nuclear Information System (INIS)

Barbarino, S.; Lattuada, M.; Riggi, F.; Spitaleri, C.; Vinciguerra, D.

1979-01-01

The quasi-free contribution to the 9 Be( 3 He,αα) 4 He reaction at low incident energy is studied under various detection configurations. The measurements performed at quasi-free angles (symmetrical and non-symmetrical configurations) furter confirm that a large region in the energy spectra is dominated by the quasi-free 5 He( 3 He,α) 4 He process. From a comparison of these results with those taken at symmetrical angles where the minimum accepted momentum of the spectator is around 70 MeV/c, the conclusion is drawn that no significant distortion is introduced by the sequential peak tails in the deduced 5 He- 4 He momentum distribution

The cosmic-ray He-3/He-4 ratio from 200 MeV per nucleon(-1) to 3.7 GeV per nucleon(-1)

DEFF Research Database (Denmark)

Reimer, O.; Menn, W.; Hof, M.

1998-01-01

by their mass using the velocity versus magnetic rigidity technique. The measured He-3/He-4 ratios are corrected to the top of the atmosphere, and a comparison with previous data is given. The observed isotopic composition is found to be generally consistent with the predictions of a standard leaky box model...

Absolute measurements of light emission from CO2/+/ and CO in the interaction of He/2 super 3 S/ with CO2.

Science.gov (United States)

Wauchop, T. S.; Broida, H. P.

1972-01-01

A flowing afterglow has been used to produce metastable He(2 super 3 S). It is shown that when He(2 super 3 S) interacts with a diatomic or triatomic molecule, its electronic excitation energy can be transferred to electronic and vibrational excitation of the molecule. To examine this mechanism, the rates for the production of electronically excited molecules, observed spectroscopically between 190 and 750 nm in the reaction of He(2 super 3 S) with CO2, have been measured. Results are tabulated.

On the use of the cold time-of-flight spectrometer in Studsvik for liquid 3He measurements

International Nuclear Information System (INIS)

Faak, Bjoern.

1989-01-01

The time-of-flight spectrometer for cold neutrons at the R2 reactor in Studsvik has been reconstructed. The design and the performance of the instrument are briefly described. Improvements required for measurement of the neutron scattering function of liquid 3 He are discussed. (author)

Measurements of the two-body photodisintegration of 3 He in the Δ(1236) resonance region

International Nuclear Information System (INIS)

Gassen, H.J.; Hegerath, A.; Loers, W.; Mecking, B.; Noeldeke, G.; Reichelt, T.; Stanek, H.

1981-07-01

The 3 He (γ,p) d reaction has been measured in the photon energy region between 200 MeV and 450 MeV at proton c.m. angles between 20 0 and 150 0 . Protons and deuterons were detected in coincidence with two time-of-flight spectromters consisting of scintillation counters; both particles were identified and their energies and angles were measured. The angular distributions show a strong forward peak. The differential cross sections fall off with increasing photon energy without showing a significant influence of the Δ resonance. (orig.)

Coupling between Solid 3He on Aerogel and Superfluid 3He in the Low Temperature Limit

International Nuclear Information System (INIS)

Bradley, D. I.; Fisher, S. N.; Guenault, A. M.; Haley, R. P.; Pickett, G. R.; Tsepelin, V.; Whitehead, R. C. V.; Skyba, P.

2006-01-01

We have cooled liquid 3He contained in a 98% open aerogel sample surrounded by bulk superfluid 3He-B at zero pressure to below 120 μK. The aerogel sample is placed in a quasiparticle blackbody radiator cooled by a Lancaster-style nuclear cooling stage to ∼200 μK. We monitor the temperature of the 3He inside the blackbody radiator using a vibrating wire resonator. We find that reducing the magnetic field on the aerogel sample causes substantial cooling of all the superfluid inside the blackbody radiator. We believe this is due to the demagnetization of the solid 3He layers on the aerogel strands. This system has potential for achieving extremely low temperatures in the confined fluid

Effects of Δ-isobar degrees of freedom on the reactions 3He(n,γ)4He and 3He(p,e+νe)4He at low-energy

International Nuclear Information System (INIS)

Schiavilla, R.

1991-01-01

The cross sections of the radiative 3 He(n,γ) 4 He and weak 3 He(p,e + ν e ) 4 He capture reactions at thermal neutron and keV proton energies have been calculated with the Variational Monte Carlo method. The ground state and low-energy continuum wave functions have been determined variationally from a realistic Hamiltonian, and include both nucleon and Δ-isobar degrees of freedom. The electroweak transition operator contains one- and two-body components in the N + Δ Hilbert space

Development of a {sup 3}He magnetometer for a neutron electric dipole moment experiment

Energy Technology Data Exchange (ETDEWEB)

Kraft, Andreas; Heil, Werner; Lauer, Thorsten; Neumann, Daniel [Johannes Gutenberg University, Institute of Physics, Mainz (Germany); Koch, Hans-Christian [Johannes Gutenberg University, Institute of Physics, Mainz (Germany); University of Fribourg, Physics Department, Fribourg (Switzerland); Daum, Manfred [Paul Scherrer Institute, Villigen (Switzerland); Pazgalev, Anatoly [Ioffe Institute, St Petersburg (Russian Federation); Sobolev, Yuri [Johannes Gutenberg University, Institute of Nuclear Chemistry, Mainz (Germany); Petersburg Nuclear Physics Institute, Gatchina (Russian Federation); Weis, Antoine [University of Fribourg, Physics Department, Fribourg (Switzerland)

2014-01-01

We have developed a highly sensitive {sup 3}He magnetometer for the accurate measurement of the magnetic field in an experiment searching for an electric dipole moment of the neutron. By measuring the Larmor frequency of nuclear spin polarized {sup 3}He atoms a sensitivity on the femto-Tesla scale can be achieved. A {sup 3}He/Cs-test facility was established at the Institute of Physics of the Johannes Gutenberg University in Mainz to investigate the readout of {sup 3}He free induction decay with a lamp-pumped Cs magnetometer. For this we designed and built an ultra-compact and transportable polarizer unit which polarizes {sup 3}He gas up to 55% by metastability exchange optical pumping. The polarized {sup 3}He was successfully transfered from the polarizer into a glass cell mounted in a magnetic shield and the {sup 3}He free induction decay was detected by a lamp-pumped Cs magnetometer. (orig.)

FLOOD 3 code conversion from Apollo to HP

Energy Technology Data Exchange (ETDEWEB)

Lee, Hae Cho [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

1996-01-01

FLOOD3 is a Fortran program used to analyze LOCA Reflood and Post Reflood transients for purpose of mechanistically generating containment sizing mass/energy source terms. The reflood time frame starts when safety injection water first enters the bottom of the core, following the initial LOCA blowdown phase, and the ends when liquid level in the core is high enough to quench the core. The post reflood phase starts at the end of reflood phase and lasts until the end of LOCA transient period. Longterm core cooling is initiated following post reflood phase. FLOOD3 code dose not contain separate capability for longterm cooling analysis. This report firstly describes detailed work carried out for installation of FLOOD3 on Apollo DN10000 and code validation results after installation. Secondly, A series of work is also describes in relation to installation of FLOOD3 on HP 9000/700 series as well as relevant code validation results. Attached is a report on software verification and validation results. 7 refs. (Author) .new.

FLOOD 3 code conversion from Apollo to HP

International Nuclear Information System (INIS)

Lee, Hae Cho

1996-01-01

FLOOD3 is a Fortran program used to analyze LOCA Reflood and Post Reflood transients for purpose of mechanistically generating containment sizing mass/energy source terms. The reflood time frame starts when safety injection water first enters the bottom of the core, following the initial LOCA blowdown phase, and the ends when liquid level in the core is high enough to quench the core. The post reflood phase starts at the end of reflood phase and lasts until the end of LOCA transient period. Longterm core cooling is initiated following post reflood phase. FLOOD3 code dose not contain separate capability for longterm cooling analysis. This report firstly describes detailed work carried out for installation of FLOOD3 on Apollo DN10000 and code validation results after installation. Secondly, A series of work is also describes in relation to installation of FLOOD3 on HP 9000/700 series as well as relevant code validation results. Attached is a report on software verification and validation results. 7 refs. (Author) .new

Comparison of four urease-dependent tests of detecting HP infection

International Nuclear Information System (INIS)

Han Yuan; Huang Gang; Zhu Cuiying; Ling Liqun

2001-01-01

Objective: The aim of this study is to compare the four urease-dependent tests of detecting Hp infection. The authors used following method: 1) rapid urease test (RUT), 2) 14 C urea breath test ( 14 C-UBT), 3) 13 C urea breath test which is measured by with infrared spectrometry ( 13 C-UBT1), 4) 13 C urea breath test with mass spectrometry ( 13 C-UBT). Methods: 54 patients underwent RUT, 14 C-UBT, 13 C-UBT1, 13 C-UBT2 respectively. Results: Sensitivity and specificity, accurate rate, positive predictive value (PPV), negative predictive value (NPV), respectively, were as follows: RUT (82.1%, 80%, 81.5%, 91.4%, 63.2%), 14 C-UBT (97.4%, 100%, 98.1%, 100%, 93.8%), 13 C-UBT1 (100%, 93.3%, 98.1%, 97.5%, 100%), 13 C-UBT2 (100%, 86.7%, 96.3%, 95.1%, 100%), PPV of four tests are not significantly different (P>0.05). Conclusion: Four urease-dependent tests are high sensitive and accurate methods for detecting Hp infection. UBT is an ideal tool for diagnosis, screen and follow-up of Hp infection

The scattering of polarized deuterons on 3He between 10 and 17 MeV

International Nuclear Information System (INIS)

Ohlsen, G.G.; Jarmie, N.; Haglund, R.H. Jr.; Brown, R.E.; Schmelzbach, P.A.

1978-01-01

Using the LASL polarized beam facility, the cross section and vector and tensor analysing powers for the 3 He(d vector,d) 3 He and 3 He(d vector,p) 4 He reactions have been measured in a large angular range at energies between 10 and 17 MeV. (orig./WL) [de

Giant asymmetry of separation and homogenization processes in solid 3He-4He solutions

International Nuclear Information System (INIS)

Grigor'ev, V.N.; Majdanov, V.A.; Penzev, A.A.; Polev, A.V.; Rubets, S.P.; Rudavskij, Eh.Ya.; Rybalko, A.S.; Syrnikov, E.V.

2005-01-01

The kinetics of the processes of separation and homogenization of solid 3 He- 4 He solutions is compared by using the precision barometry. The experiments were made with the initial specimens of three types: weak 3 He- 4 He and 4 He- 3 He solutions and concentrated 3 He- 4 He ones. It is found that the homogenization rate at the initial stage may be more than 500 times higher that the rate of separation. This is the case for all types of the solutions studied. The appreciable rate of phase separation in the concentrated solutions where, according to the modern concepts, impurity atoms in quantum crystals should be localized, suggests that in such conditions there is a new unknown mechanism of mass-transfer, while the fast homogenization points to a nondiffusion nature of the process

Polarized (3) He Spin Filters for Slow Neutron Physics.

Science.gov (United States)

Gentile, T R; Chen, W C; Jones, G L; Babcock, E; Walker, T G

2005-01-01

Polarized (3)He spin filters are needed for a variety of experiments with slow neutrons. Their demonstrated utility for highly accurate determination of neutron polarization are critical to the next generation of betadecay correlation coefficient measurements. In addition, they are broadband devices that can polarize large area and high divergence neutron beams with little gamma-ray background, and allow for an additional spin-flip for systematic tests. These attributes are relevant to all neutron sources, but are particularly well-matched to time of flight analysis at spallation sources. There are several issues in the practical use of (3)He spin filters for slow neutron physics. Besides the essential goal of maximizing the (3)He polarization, we also seek to decrease the constraints on cell lifetimes and magnetic field homogeneity. In addition, cells with highly uniform gas thickness are required to produce the spatially uniform neutron polarization needed for beta-decay correlation coefficient experiments. We are currently employing spin-exchange (SE) and metastability-exchange (ME) optical pumping to polarize (3)He, but will focus on SE. We will discuss the recent demonstration of 75 % (3)He polarization, temperature-dependent relaxation mechanism of unknown origin, cell development, spectrally narrowed lasers, and hybrid spin-exchange optical pumping.

Overlap integrals of model wave functions of 4He and 3He,3H nuclei

International Nuclear Information System (INIS)

Voloshin, N.I.; Levshin, E.B.; Fursa, A.D.

1990-01-01

Overlap integrals of wave functions 4 He nucleus and 3 He and 3 H nuclei are calculated. Two types of model wave functions are used to describe the structure of nuclei. The wace function is taken as a product of the one-particle Gaussian functions of the Gaussian type in the second case

HP1γ function is required for male germ cell survival and spermatogenesis

Directory of Open Access Journals (Sweden)

Brown Jeremy P

2010-04-01

Full Text Available Abstract Background HP1 proteins are conserved components of eukaryotic constitutive heterochromatin. In mammals, there are three genes that encode HP1-like proteins, termed HP1α, HP1β and HP1γ, which have a high degree of homology This paper describes for the first time, to our knowledge, the physiological function of HP1γ using a gene-targeted mouse. Results While targeting the Cbx3 gene (encoding the HP1γ protein with a conditional targeting vector, we generated a hypomorphic allele (Cbx3hypo, which resulted in much reduced (barely detectable levels of HP1γ protein. Homozygotes for the hypomorphic allele (Cbx3hypo/hypo are rare, with only 1% of Cbx3hypo/hypo animals reaching adulthood. Adult males exhibit a severe hypogonadism that is associated with a loss of germ cells, with some seminiferous tubules retaining only the supporting Sertoli cells (Sertoli cell-only phenotype. The percentage of seminiferous tubules that are positive for L1 ORF1 protein (ORF1p in Cbx3hypo/hypo testes is greater than that for wild-type testes, indicating that L1 retrotransposon silencing is reversed, leading to ectopic expression of ORF1p in Cbx3hypo/hypo germ cells. Conclusions The Cbx3 gene product (the HP1γ protein has a non-redundant function during spermatogenesis that cannot be compensated for by the other two HP1 isotypes. The Cbx3hypo/hypo spermatogenesis defect is similar to that found in Miwi2 and Dnmt3L mutants. The Cbx3 gene-targeted mice generated in this study provide an appropriate model for the study of HP1γ in transposon silencing and parental imprinting.

Non-intrusive measurement of tritium activity in waste drums by modelling a {sup 3}He leak quantified by mass spectrometry; Mesure non intrusive de l'activite de futs de dechets trities par modelisation d'une fuite {sup 3}He et sa quantification par spectrometrie de masse

Energy Technology Data Exchange (ETDEWEB)

Demange, D

2002-07-03

This study deals with a new method that makes it possible to measure very low tritium quantities inside radioactive waste drums. This indirect method is based on measuring the decaying product, {sup 3}He, and requires a study of its behaviour inside the drum. Our model considers {sup 3}He as totally free and its leak through the polymeric joint of the drum as two distinct phenomena: permeation and laminar flow. The numerical simulations show that a pseudo-stationary state takes place. Thus, the {sup 3}He leak corresponds to the tritium activity inside the drum but it appears, however, that the leak peaks when the atmospheric pressure variations induce an overpressure in the drum. Nevertheless, the confinement of a drum in a tight chamber makes it possible to quantify the {sup 3}He leak. This is a non-intrusive measurement of its activity, which was experimentally checked by using reduced models, representing the drum and its confinement chamber. The drum's confinement was optimised to obtain a reproducible {sup 3}He leak measurement. The gaseous samples taken from the chamber were purified using selective adsorption onto activated charcoals at 77 K to remove the tritium and pre-concentrate the {sup 3}He. The samples were measured using a leak detector mass spectrometer. The adaptation of the signal acquisition and the optimisation of the analysis parameters made it possible to reach the stability of the external calibrations using standard gases with a {sup 3}He detection limit of 0.05 ppb. Repeated confinement of the reference drums demonstrated the accuracy of this method. The uncertainty of this non-intrusive measurement of the tritium activity in 200-liter drums is 15% and the detection limit is about 1 GBq after a 24 h confinement. These results led to the definition of an automated tool able to systematically measure the tritium activity of all storage waste drums. (authors)

Determination of the π3He3H coupling constant

International Nuclear Information System (INIS)

Nichitiu, F.; Sapozhnikov, M.G.

1977-01-01

Despersion relations for the real part of the antisymmetric amplitude of the π +-3 He scattering have been used in order to determine the π 3 He 3 H coupling constant. The coupling constant value determined by this method is larger than the elementary pion-nucleon coupling constant, but is in good agreement with the value obtained by another method. The obtained value is f 2 sub(π 3 He 3 H) = 0.12+-0.01. Shown is the importance of using the Coulomb corrections for dispersion relation calculations because the value of π 3 He 3 H coupling constant obtained with corrected total cross sections is larger by about 0.014 than the one obtained without these corrections. The best energy ranges for future π 3 He experiments are commented

Celiac disease and Hp infection association in Iran Enfermedades celiacas e infección por Hp en Irán

Directory of Open Access Journals (Sweden)

M. Rostami-Nejad

2009-12-01

Full Text Available Background: we assessed the prevalence, the related symptoms, and the endoscopic and histologic gastric features of celiac disease (CD in patients with Helicobacter pylori (Hp. Methods: 450 dyspeptic patients were studied. Biopsies of gastric antrum and duodenum, CD serology, and total IgA were obtained. Histological findings were scored with the Marsh-Rostami criteria. Results: 411 (91.3% patients were Hp positive. Duodenal histology was normal in 385 (85.6% patients, 124 (27.5% had duodenitis and 28 (6.2% showed duodenal abnormalities (Marsh I-IIIc. Twenty three/28 (82.1% patients with malabsorption pattern were also Hp positive. Serological analysis: 12 of 31 (38.7% positive patients had abnormal histology (Marsh I,-IIIc. Nine out 450 patients were IgA deficient; none of them was serologically positive for CD. Conclusion: although a high prevalence of Hp infection was found in this study, the relationship between Hp infection and CD was similar to that reported in other geographic areas.

High-resolution mapping reveals links of HP1 with active and inactive chromatin components.

Directory of Open Access Journals (Sweden)

Elzo de Wit

2007-03-01

Full Text Available Heterochromatin protein 1 (HP1 is commonly seen as a key factor of repressive heterochromatin, even though a few genes are known to require HP1-chromatin for their expression. To obtain insight into the targeting of HP1 and its interplay with other chromatin components, we have mapped HP1-binding sites on Chromosomes 2 and 4 in Drosophila Kc cells using high-density oligonucleotide arrays and the DNA adenine methyltransferase identification (DamID technique. The resulting high-resolution maps show that HP1 forms large domains in pericentric regions, but is targeted to single genes on chromosome arms. Intriguingly, HP1 shows a striking preference for exon-dense genes on chromosome arms. Furthermore, HP1 binds along entire transcription units, except for 5' regions. Comparison with expression data shows that most of these genes are actively transcribed. HP1 target genes are also marked by the histone variant H3.3 and dimethylated histone 3 lysine 4 (H3K4me2, which are both typical of active chromatin. Interestingly, H3.3 deposition, which is usually observed along entire transcription units, is limited to the 5' ends of HP1-bound genes. Thus, H3.3 and HP1 are mutually exclusive marks on active chromatin. Additionally, we observed that HP1-chromatin and Polycomb-chromatin are nonoverlapping, but often closely juxtaposed, suggesting an interplay between both types of chromatin. These results demonstrate that HP1-chromatin is transcriptionally active and has extensive links with several other chromatin components.

Haptoglobin genotyping of Vietnamese: global distribution of HP del, complete deletion allele of the HP gene.

Science.gov (United States)

Soejima, Mikiko; Agusa, Tetsuro; Iwata, Hisato; Fujihara, Junko; Kunito, Takashi; Takeshita, Haruo; Lan, Vi Thi Mai; Minh, Tu Binh; Takahashi, Shin; Trang, Pham Thi Kim; Viet, Pham Hung; Tanabe, Shinsuke; Koda, Yoshiro

2015-01-01

The haptoglobin (HP) gene deletion allele (HP(del)) is responsible for anhaptoglobinemia and a genetic risk factor for anaphylaxis reaction after transfusion due to production of the anti-HP antibody. The distribution of this allele has been explored by several groups including ours. Here, we studied the frequency of HP(del) in addition to the distribution of common HP genotypes in 293 Vietnamese. The HP(del) was encountered with the frequency of 0.020. The present result suggested that this deletion allele is restricted to East and Southeast Asians. Thus, this allele seems to be a potential ancestry informative marker for these populations. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Structure of the 8He exotic nucleus by the direct reactions 8He(p, p')8He, 8He(p,d)7He and 8He(p,t)6He

International Nuclear Information System (INIS)

Skaza, Flore

2004-01-01

The elastic and inelastic scattering of an 8 He beam on a proton target have been measured at GANIL. The first 8 He beam produced by the SPIRAL facility at an energy of 15.6 A.MeV impinged on a proton target. The experimental setup was composed by the eight telescopes MUST array dedicated to the measure of the light charged particles, by a scintillator plastic wall for the detection of heavy projectile, and by two beam tracking detectors CATS for the measure event by event of the incident position and angle of the beam on the target. This setup allowed also to measure the one and two neutron transfer reactions 8 He(p,d) 7 He and 8 He(p,t) 6 He. The excitation energy spectrum for 6,7,8 He and the angular distributions associated to each reaction have been measured. The observed excited states are in agreement with the data of the literature. We indicate the presence of a first excited state for 7 He at 0.9 MeV and we give for the first time the position of a second excited state in 8 He at 5.4 MeV; the presence of such state was just suggested in a previous experiment. CCBA calculations allowed to extract a spectroscopic factor of 4.4 ± 1.4 for the pick-up of one neutron from 8 He to 7 He. This value is in agreement with a closed p3/2 sub-shell for 8 He. To analyse the angular distributions for elastic and inelastic scattering, it was necessary to take into account in the formalism used to describe the reactions, via coupled channels reactions calculations, the couplings to the one neutron transfer reaction. (author) [fr

Structure properties of the 3He-4He mixture at T = O K

International Nuclear Information System (INIS)

Boronat, J.; Polls, A.; Fabrocini, A.

1993-01-01

The spatial structure properties of 3 He- 4 He mixtures at T = O K are investigated using the hypernetted-chain formalism. The variational wave function used to describe the ground-state of the mixture is a simple generalization of the trial wave functions for pure phases and contains two- and three-body correlations. The elementary diagrams are taken into account by means of an extension of the scaling approximation to the mixtures. The two-body distribution (g (α,β) (r)) and the structure functions (S (α,β) (k)) together with the different spin-spin distribution functions for the 3 He component in the mixture are analyzed for several concentrations of 3 He. Two sum-rules, for the direct and the exchange part of the g (3,3) (r), are used to ascertain the importance of the full treatment of the Fermi statistics in the calculation. The statistical correlations are found responsible for the main differences between the several components of the distribution function. Due to its low concentration, 3 He behaves as a quasi-free Fermi gas, as far as the statistical correlations are concerned, although it is strongly correlated with the 4 He atoms through the interatomic potential

Experimental considerations on producing highly polarized liquid 3He in a matrix of solid 4He

International Nuclear Information System (INIS)

Greenberg, A.S.; Hebral, B.; Papoular, M.; Beal-Monod, M.T.

1980-01-01

Two experiments are briefly reviewed in which droplets of 3 He were formed in solid 4 He. These experiments indicate such conditions are favorable for the production of quasi-stable highly polarized liquid 3 He. A solid solution of dilute 3 He in 4 He is proposed as a promising system to produce experimentally realizable highly polarized liquid 3 He using the Castaing-Nozieres decompression

Anomalous Quasiparticle Reflection from the Surface of a ^{3}He-^{4}He Dilute Solution.

Science.gov (United States)

Ikegami, Hiroki; Kim, Kitak; Sato, Daisuke; Kono, Kimitoshi; Choi, Hyoungsoon; Monarkha, Yuriy P

2017-11-10

A free surface of a dilute ^{3}He-^{4}He liquid mixture is a unique system where two Fermi liquids with distinct dimensions coexist: a three-dimensional (3D) ^{3}He Fermi liquid in the bulk and a two-dimensional (2D) ^{3}He Fermi liquid at the surface. To investigate a novel effect generated by the interaction between the two Fermi liquids, the mobility of a Wigner crystal of electrons formed on the free surface of the mixture is studied. An anomalous enhancement of the mobility, compared with the case where the 3D and 2D systems do not interact with each other, is observed. The enhancement is explained by the nontrivial reflection of 3D quasiparticles from the surface covered with the 2D ^{3}He system.

Development of a 3He nuclear spin flip system on an in-situ SEOP 3He spin filter and demonstration for a neutron reflectometer and magnetic imaging technique

International Nuclear Information System (INIS)

Hayashida, H; Kira, H; Miyata, N; Akutsu, K; Mizusawa, M; Parker, J D; Matsumoto, Y; Oku, T; Sakai, K; Hiroi, K; Shinohara, T; Takeda, M; Yamazaki, D; Oikawa, K; Harada, M; Ino, T; Imagawa, T; Ohkawara, M; Ohoyama, K; Kakurai, K

2016-01-01

We have been developing a 3 He neutron spin filter (NSF) using the spin exchange optical pumping (SEOP) technique. The 3 He NSF provides a high-energy polarized neutron beam with large beam size. Moreover the 3 He NSF can work as a π-flipper for a polarized neutron beam by flipping the 3 He nuclear spin using a nuclear magnetic resonance (NMR) technique. For NMR with the in-situ SEOP technique, the polarization of the laser must be reversed simultaneously because a non-reversed laser reduces the polarization of the spin-flipped 3 He. To change the polarity of the laser, a half-wavelength plate was installed. The rotation angle of the half-wavelength plate was optimized, and a polarization of 97% was obtained for the circularly polarized laser. The 3 He polarization reached 70% and was stable over one week. A demonstration of the 3 He nuclear spin flip system was performed at the polarized neutron reflectometer SHARAKU (BL17) and NOBORU (BL10) at J-PARC. Off-specular measurement from a magnetic Fe/Cr thin film and magnetic imaging of a magnetic steel sheet were performed at BL17 and BL10, respectively. (paper)

Measurement of observables in the pion-nucleon system and investigation of charge symmetry in 3H and 3He

International Nuclear Information System (INIS)

Sadler, M.E.

1989-01-01

This report describes the pion scattering programs in which Abilene Christian University collaborated under this contract which ended May 14, 1988. The experiments were conducted at the Clinton P. Anderson Meson Physics Facility at Los Alamos (LAMPF). The experiments were performed in collaboration with UCLA, George Washington University, LAMPF Groups MP-4, MP-10 and MP-13, and Catholic University. The measurements included: (1) a complete set of observables in the pion-nucleon system in the momentum interval 400--700 MeV/c, (2) differential cross sections at low energy for pion-nucleon charge exchange, and (3) elastic and inelastic scattering of π ± on 3 H and 3 He

3He Abundances in Planetary Nebulae

Science.gov (United States)

Guzman-Ramirez, Lizette

2017-10-01

Determination of the 3He isotope is important to many fields of astrophysics, including stellar evolution, chemical evolution, and cosmology. The isotope is produced in stars which evolve through the planetary nebula phase. Planetary nebulae are the final evolutionary phase of low- and intermediate-mass stars, where the extensive mass lost by the star on the asymptotic giant branch is ionised by the emerging white dwarf. This ejecta quickly disperses and merges with the surrounding ISM. 3He abundances in planetary nebulae have been derived from the hyperfine transition of the ionised 3He, 3He+, at the radio rest frequency 8.665 GHz. 3He abundances in PNe can help test models of the chemical evolution of the Galaxy. Many hours have been put into trying to detect this line, using telescopes like the Effelsberg 100m dish of the Max Planck Institute for Radio Astronomy, the National Radio Astronomy Observatory (NRAO) 140-foot telescope, the NRAO Very Large Array, the Arecibo antenna, the Green Bank Telescope, and only just recently, the Deep Space Station 63 antenna from the Madrid Deep Space Communications Complex.

Effect of hypoproteinemia (HP) upon FT4 and FT3 by kinetic radioligandassay (RLA)

International Nuclear Information System (INIS)

Bottger, I.G.; Schneck, H.J.

1985-01-01

HP, especially hypoalbuminemia (HA), has been associated with false low FT4 by RLA, predominantly of the analogue tracer type. Based upon previous more favourable findings in severe nonthyroidal illness (NTI), this study was designed to study this problem in more detail. Two groups of patients with severe NTI (polytrauma) were selected on the basis of their total serum protein (TSP) concentration and studied during intensive-care. Group I: N = 25, TSP 5.9 g/dl (6.0 - 7.7), A/G: 1.5, sera: N = 76. I and II: low-dose heparin (i.v. 5000 U/24 h), non-detectable in the periphery. The RLA kits used were: FT4/T4 and FT3/T3 (kinetic two-tube), and TBG, Corning Medical, rT3, Serono, TSH, Henning-Berlin, TSP/electrophoresis standard technique. The findings indicate: 1. Typical findings for follow-up of severe NTI; 2. No detection of a significant effect of HP/HA upon these RLAs for FT4 and FT3; and 3. The inter-group differences are most likely due to more severe NT1 in I (R/sub x/, A/G, rT3)

Measurement of observables in the pion-nucleon system and investigation of charge symmetry in 3H and 3He

International Nuclear Information System (INIS)

Sadler, M.E.; Isenhower, L.D.

1990-01-01

This report discusses the following: pion-nucleon program; a search for neutral pions from the spontaneous fission of 252 Cf; elastic and inelastic pion scattering on 3 H and 3 He; nuclear dependence of charm and beauty quark production and a study of two-prong decays of neutral B mesons; measurement of π - p → π 0 n in the cusp region at the Leningrad Nuclear Physics Institute (LNPI); a test of consistency of low-energy pion-nucleon differential cross sections with total cross sections; and design of a high energy photon calorimeter for the neutral meson spectrometer

Autoionization spectra of He excited by fast (MeV) H+, He+, and Li/sup n+/ (n = 1,2,3) ions

International Nuclear Information System (INIS)

Schneider, D.; Arcuni, P.; Bruch, P.; Stoeffler, W.

1983-01-01

Autoionization spectra of He following excitation by 1 to 3 MeV H + , He + , and Li/sup n+/ (n = 1,2,3) have been measured as a function of observation angle. The (2p 2 ) 1 D and (2s2p) 1 P resonances have been examined and a strong dependence on projectile velocities, charge state and observation angle was found

Influence of the intermediate bcc phase on the evolution of superfluid inclusions in hcp matrix 3He-4He

International Nuclear Information System (INIS)

Birchenko, A.P.; Mikhin, N.P.; Neoneta, A.S.; Rudavskij, Eh.Ya.; Fisun, Ya.Yu.

2016-01-01

The evolution of liquid inclusions which are formed in the hcp matrix by rapid cooling of the 3 He- 4 He solution containing 1.05% 3 He was studied by pulse NMR. The diffusion coefficient of 3 He in the liquid was measured by two-pulses spin-echo method during evolution of the inclusions. Measurements were carried out at 1.67 K which corresponds to the bcc phase existence in the phase diagram, as well as at 1.38 K, where the bcc phase is absent. It is found that in the process of the evolution, in both cases the size of the liquid inclusions is less than diffusion length and so the diffusion is restricted. The measured restricted dif-fusion coefficient allowed to find the characteristic size of the inclusions. In the first case, during the evolution of liquid inclusions, dendrites of intermediate bcc phase is forming and the inclusions are separating into a lot of smaller droplets. Due to the rapid growth of the bcc dendrites, the droplet size decreases rapidly, and the process comes to disappearance of bcc phase and an amorphous state appearance. The results obtained by measuring the diffusion coefficient, correlated with the behavior of the spin-lattice relaxation time in such a system. In the second case at a lower temperature bcc phase is not formed, and the size of the liquid inclusions decreases very slow until the completion of their solidification.

Quenching of 4He(21S,21P) and 3He(21S,21P) states by collisions with Ne(1S0) atoms

International Nuclear Information System (INIS)

Blagoev, K.B.; Dimova, E.; Petrov, G.M.

2004-01-01

The cross sections and rate constants for quenching 4 He(2 1 S), 4 He(2 1 P), 3 He(2 1 S) and 3 He(2 1 P) states by collisions with ground state Ne atoms are measured by a time-resolved method in a He-Ne electron beam excited plasma at low pressure. These rate constants at T g =600 K are: k 4 He(2 1 S) =(1.6±0.2)x10 -10 , k 4 He(2 1 P) =(3.4±2.5)x10 -10 , k 3 He(2 1 S) =(1.6±0.2)x10 -10 and k 3 He(2 1 P) =(5.7±1.2)x10 -10 cm 3 s -1 . The cross sections derived from the rate constant are σ 4 He(2 1 S) =(8.4±0.8)x10 -16 , σ 4 He(2 1 P) =(1.8±1.3)x10 -15 , σ 3 He(2 1 S) =(7.1±0.9)x10 -16 and σ 3 He(2 1 P) =(2.6±0.5)x10 -15 cm 2 , respectively. The diffusion coefficient of 3 He(2 1 S) in 3 He is estimated to be D 3 He(2 1 S)- 3 He =1.9D 4 He(2 1 S)- 4 He , based on comparison with 4 He. A time-dependent collisional radiative model for an e-beam sustained He-Ne plasma is developed and the predicted line intensity of NeI λ=6328 A line is compared with the experimental data. The influence of different processes involved in population and depopulation dynamics of He(2 1 S) state are evaluated

Progress in Polarized 3He Ion Source at RCNP

International Nuclear Information System (INIS)

Tanaka, M.; Takahashi, Y.; Shimoda, T.; Yasui, S.; Yosoi, M.; Takahisa, K.; Shimakura, N.; Plis, Yu. A.; Donets, E. D.

2007-01-01

A long history on the polarized 3He ion source developed at RCNP is presented. We started with an 'OPPIS' (Optical Pumping Polarized Ion Source) and later found the fundamental difficulties in the OPPIS. To overcome them an 'EPPIS' (Electron Pumping Polarized Ion Source) was proposed and its validity was experimentally proven. However, a serious technical disadvantage was also found in the EPPIS. To avoid this disadvantage we proposed a new concept, 'SEPIS' (Spin Exchange Polarized Ion Source), which uses an enhanced spin-exchange cross section theoretically expected at low 3He+ incident energies in the 3He+ + Rb system. Next, we describe the present status of the SEPIS development: construction of a bench test device allowing the measurements of not only the spin-exchange cross sections σse but also the electron capture cross sections σec for the 3He+ + Rb system. The latest experimental data on σec are presented and compared with other previous experimental data and the theoretical calculations.Finally, a design study of the SEPIS for practical use in nuclear (cyclotron) and particle physics (synchrotron) is shortly mentioned

3He(α,γ7Be cross section measured using complementary techniques

Directory of Open Access Journals (Sweden)

Carmona-Gallardo M.

2014-03-01

Full Text Available The astrophysical S-factor for the 3He(α,γ7Be reaction plays an important role in the Solar Standard Model and in the Big Bang Nucleosynthesis scenario. The advances from two recent experiments performed using complementary techniques at center of mass (C.M. energies between 1 and 3 MeV are discussed.

Effect of He-Ne laser irradiation on hydrogen production by Enterobacter aerogenes

Energy Technology Data Exchange (ETDEWEB)

Lu, Wenyu; Wen, Jianping; Jia, Xiaoqiang; Sun, Bing; Chen, Yu.; Liu, Minhui [Department of Biochemical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072 (China)

2008-01-15

Enterobacter aerogenes W-23 bacteria exhibiting hydrogen production (HP) ability were exposed to He-Ne laser irradiation (632.8 nm) to improve the HP ability. Upon the optimum irradiation dosage (18 mW for 22.2 min), a stable positive mutant strain E. aerogenes HB-5M was obtained. The maximum specific rate of HP of the mutant strain was 0.042h{sup -1}, which was about twice that of the wild strain. It was suggested that the higher HP ability of the mutant strain might be presumably attributed to the enhancement of hydrogenase activity. In addition, the kinetic parameters of cell growth, substrate consumption and HP of the wild strain and its mutant strain were regressed to simulate the fermentation process of E. aerogenes. The simulated results agreed well with the experimental data. (author)

Evidence for pion exchange currents in the analysis of the /sup 4/He(p,d)/sup 3/He reaction at intermediate energies

Energy Technology Data Exchange (ETDEWEB)

Shepard, J R; Rost, E; Smith, G R [Colorado Univ., Boulder (USA). Nuclear Physics Lab.

1979-12-01

Previous unsuccessful analyses of /sup 4/He(p,d)/sup 3/He at intermediate energies have employed densities based directly on the measured e/sup -/ + /sup 4/He elastic scattering. When the effects of pion exchange currents are removed, the resulting DWBA analysis is in qualitative agreement with the experimental data.

Precise measurement of magnetic field gradients from free spin precession signals of He-3 and Xe-129 magnetometers

NARCIS (Netherlands)

Allmendinger, Fabian; Blümler, Peter; Doll, Michael; Grasdijk, Oliver; Heil, Werner; Jungmann, Klaus; Karpuk, Sergej; Krause, Hans-Joachim; Offenhäuser, Andreas; Repetto, Maricel; Schmidt, Ulrich; Sobolev, Yuri; Tullney, Kathlyne; Willmann, Lorenz; Zimmer, Stefan

2017-01-01

We report on precise measurements of magnetic field gradients extracted from transverse relaxation rates of precessing spin samples. The experimental approach is based on the free precession of gaseous, nuclear spin polarized He-3 and (12)9Xe atoms in a spherical cell inside a magnetic guiding field

Inelastic pion scattering from 3H and 3He

International Nuclear Information System (INIS)

Berman, B.L.; Anderson, G.C.; Briscoe, W.J.; Mokhtari, A.; Petrov, A.M.; Sadler, M.E.; Barlow, D.B.; Nefkens, B.M.K.; Pillai, C.

1995-01-01

Cross sections have been measured for the inelastic scattering of π + and π - mesons from 3 H and 3 He in the 10-MeV interval just above the breakup thresholds, for incident pion energies of 142, 180, and 220 MeV and scattering angles of 40 degree, 60 degree, 80 degree, 90 degree, and 110 degree. No significant departure from unity is observed for the ratios of charge-symmetric cross sections. Comparisons are made with elastic pion-scattering and inelastic electron-scattering data

Non-intrusive measurement of tritium activity in waste drums by modelling a {sup 3}He leak quantified by mass spectrometry; Mesure non intrusive de l'activite de futs de dechets trities par modelisation d'une fuite {sup 3}He et sa quantification par spectrometrie de masse

Energy Technology Data Exchange (ETDEWEB)

Demange, D

2002-07-03

This study deals with a new method that makes it possible to measure very low tritium quantities inside radioactive waste drums. This indirect method is based on measuring the decaying product, {sup 3}He, and requires a study of its behaviour inside the drum. Our model considers {sup 3}He as totally free and its leak through the polymeric joint of the drum as two distinct phenomena: permeation and laminar flow. The numerical simulations show that a pseudo-stationary state takes place. Thus, the {sup 3}He leak corresponds to the tritium activity inside the drum but it appears, however, that the leak peaks when the atmospheric pressure variations induce an overpressure in the drum. Nevertheless, the confinement of a drum in a tight chamber makes it possible to quantify the {sup 3}He leak. This is a non-intrusive measurement of its activity, which was experimentally checked by using reduced models, representing the drum and its confinement chamber. The drum's confinement was optimised to obtain a reproducible {sup 3}He leak measurement. The gaseous samples taken from the chamber were purified using selective adsorption onto activated charcoals at 77 K to remove the tritium and pre-concentrate the {sup 3}He. The samples were measured using a leak detector mass spectrometer. The adaptation of the signal acquisition and the optimisation of the analysis parameters made it possible to reach the stability of the external calibrations using standard gases with a {sup 3}He detection limit of 0.05 ppb. Repeated confinement of the reference drums demonstrated the accuracy of this method. The uncertainty of this non-intrusive measurement of the tritium activity in 200-liter drums is 15% and the detection limit is about 1 GBq after a 24 h confinement. These results led to the definition of an automated tool able to systematically measure the tritium activity of all storage waste drums. (authors)

3He neutral current detectors at SNO

International Nuclear Information System (INIS)

Elliott, S.R.; Browne, M.C.; Doe, P.J.

1998-01-01

The flux of solar neutrinos measured via charged and neutral current interactions can provide a model independent test of neutrino oscillations. Since the Sudbury Neutrino Observatory uses heavy water as a target, it has a large sensitivity to both interactions. A technique for observing the neutral current breakup of the deuteron using 3 He proportional counters is described

He 3 -Xe 129 Comagnetometery using Rb 87 Detection and Decoupling

Science.gov (United States)

Limes, M. E.; Sheng, D.; Romalis, M. V.

2018-01-01

We describe a He 3 -Xe 129 comagnetometer using Rb 87 atoms for noble-gas spin polarization and detection. We use a train of Rb 87 π pulses and σ+/σ- optical pumping to realize a finite-field Rb magnetometer with suppression of spin-exchange relaxation. We suppress frequency shifts from polarized Rb by measuring the He 3 and Xe 129 spin precession frequencies in the dark, while applying π pulses along two directions to depolarize Rb atoms. The plane of the π pulses is rotated to suppress the Bloch-Siegert shifts for the nuclear spins. We measure the ratio of He 3 to Xe 129 spin precession frequencies with sufficient absolute accuracy to resolve Earth's rotation without changing the orientation of the comagnetometer. A frequency resolution of 7 nHz is achieved after integration for 8 h without evidence of significant drift.

Effective mass of liquid 3He using the melting curve data

International Nuclear Information System (INIS)

Chaddah, P.; Simmons, R.O.; Illinois Univ., Urbana

1980-01-01

Measurements of dp/dt and of the liquid and solid molar volumes along the melting curve of 3 He can be used to obtain information about the Fermi liquid parameter Esub(f) = p 2 sub(f)/2m* of liquid 3 He. Data at temperatures reasonably far above the Neel temperature of the solid, but low enough so that the first finite-temperature correction term in Fermi liquid theory is not large are used. It is shown that in spite of uncertainties in the solid 3 He entropy because of uncertainties in the knowledge of the exchange mechanism, the melting curve data provide a check on the different sets of values for m* quoted in literature. The possible effect of ground state vacancies, whose existence in BCC 3 He has been speculated on this analysis is also discussed. (author)

The Spin Structure of the Neutron Determined Using a Polarized He-3 Target

Energy Technology Data Exchange (ETDEWEB)

Middleton, H

2004-01-06

Described is a study of the internal spin structure of the neutron performed by measuring the asymmetry in spin-dependent deep inelastic scattering of polarized electrons from nuclear polarized {sup 3}He. Stanford Linear Accelerator experiment E142's sample of 400 million scattering events collected at beam energies between 19 and 26 GeV led to the most precise measurement of a nucleon spin structure function to date. The {sup 3}He target represents a major advance in polarized target technology, using the technique of spin exchange with optically pumped rubidium vapor to produce a typical {sup 3}He nuclear polarization of 34% in a 30cm long target cell with a gas density of 2.3 x 10{sup 20} cm{sup -3}. The target polarization was measured to {+-}7% using an Adiabatic Fast Passage NMR system calibrated with the thermal equilibrium polarization of the protons in a sample of water. The relatively high polarization and target thickness were the result of the development of large volume glass target cells which had inherent nuclear spin relaxation times for the {sup 3}He gas of as long as 70 hours. A target cell production procedure is presented which focuses on special glass blowing techniques to minimize surface interactions with the {sup 3}He nuclei and careful gas purification and vacuum system procedures to reduce relaxation inducing impurities.

3He/4He ratio, noble gas abundance and K-Ar dating of diamonds - an attempt to search for the records of early terrestrial history

International Nuclear Information System (INIS)

Ozima, M.; Zashu, S.; Nitoh, O.

1983-01-01

The 3 He/ 4 He ratios measured in 27 Southern Africa diamond stones, four from Premier Mine and the rest of unidentified origin, range from 4.2 x 10 -8 to 3.2 x 10 -4 , with three stones above 1 x 10 -4 . We conclude that the initial helium isotopic ratio ( 3 He/ 4 He) 0 in the earth was significantly higher than that of the planetary helium-A ( 3 He/ 4 He = 1.42 x 10 -4 ), but close to the solar helium ( 3 He/ 4 He = approx. 4 x 10 -4 ). The apparent K-Ar ages for the twelve diamonds of unidentified origin show enormously old age, indicating excess argon-40. 3 He/ 4 He evolution in diamonds suggests that the diamonds with the high 3 He/ 4 He ratio (> 2 x 10 -4 ) may be as old as the earth. Noble gas elemental abundance in the diamonds relative to the air noble gas abundance shows monotonic decrease with a decreasing mass number. This paper discusses the implications of these observations on the early solar system and the origin of diamonds. (author)

Measurement of the deuteron tensor polarization at the sup 3 He->d+p vertex up to internal momenta of 0.43 GeV/c

CERN Document Server

Sitnik, I M; Tomasi-Gustafsson, E; Azhgirey, L S; Ball, J; Bimbot, L; Bisson, Y; Boivin, M; Borzunov, Yu T; Boyard, J L; Courtat, P; Gacougnolle, R; Garçon, M; Golovanov, L B; Hennino, T; Jones, M; Kirillov, D A; Kunne, Ronald Alexander; Malinina, L V; Nedev, S; Piskunov, N M; Punjabi, V; Rekalo, M P; Sans, J L; Skowron, R; Strokovsky, E A; Yonnet, J

2000-01-01

The tensor polarization of deuterons, rho sub 2 sub 0 , emitted at zero degree in the sup 1 H( sup 3 He, d-reversible)X reaction, was measured at the Saturne National Laboratory in Saclay, using the SPES4 magnetic channel and the HYPOM polarimeter. The momentum of the detected deuterons was kept fixed at 3.77 GeV/c, while the momentum of the sup 3 He beam was varied from 5.66 to 4.60 GeV/c; this provided a range of internal momenta of a deuteron in sup 3 He, k, from 0 to 0.43 GeV/c.

3He impurities on liquid 4He: possible existence of excited states

International Nuclear Information System (INIS)

Pavloff, N.; Treiner, J.

1989-01-01

We study, using a density functional approach, the properties of the two dimensional system formed by 3 He atoms on the surface of liquid 4 He, as a function of 3 He coverage N s . We find that the excited state recently proposed by Dalfovo and Stringari in the case of infinite dilution does survive when the number of surface 3 He atoms increases. For small values of N s , the surface tension σ is, as expected, linear in N s 2 . For N s ≅0.035 atom per square-Angstrom, i.e. half a monolayer, a new type of surface state starts being occupied, and this feature manifests itself by a change in the slope of σ as a function of N s 2 and, more clearly, by a discontinuity in the surface specific heat, which increases by a factor of almost 2. These predictions call for experimental investigations

Energy spectrum of surface electrons over a {sup 3}He – {sup 4}He solution with a spatially non-uniform distribution of the light isotope

Energy Technology Data Exchange (ETDEWEB)

Bezsmolnyy, Ya.Yu.; Sokolova, E.S.; Sokolov, S.S. [B.Verkin Institute for Low Temperature Physics and Engineering of the National Academy of Sciences of Ukraine, 47 Prospekt Nauky, 61103 Kharkov (Ukraine); Studart, Nelson [Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, Av. dos Estados, 5001, 09210-580 Santo André, São Paulo (Brazil); Departamento de Física, Universidade Federal de São Carlos, via Washington Luís, km 235, 13565-905 Säo Carlos, São Paulo (Brazil)

2017-02-15

The energy gap between the ground and first excited energy levels of surface electrons deposited over a dilute {sup 3}He - {sup 4}He solution is evaluated. Two spatial distributions of {sup 3}He atoms near the free surface solution are considered. One consists of a thin though macroscopic {sup 3}He film and in the other the {sup 3}He concentration varies continuously from the surface inside the liquid. The energy gap is calculated as a function of the parameters of the {sup 3}He spatial distribution for these distributions. It is shown that the energy gap dependence on the distribution parameters allows using measurements of intersubband transitions of the surface electrons to determine the {sup 3}He concentration distribution and, in principle, the nature of the spatial distribution of the light isotope near the surface of the solution.

The mobility of negative ions in superfluid 3He

International Nuclear Information System (INIS)

Solomaa, M.

1982-01-01

This article reviews recent experimental and theoretical work on the mobility of negative ions in the superfluid A and B phases of liquid 3 He. In the normal Fermi liquid at temperatures below approximately 50 mK and also in the superfluid close to the superfluid transition temperature, Tsub(c), the mobility of a negative ion may simply be considered as limited by the elastic scattering of 3 He quasiparticles. This explains the constancy of the ion mobility in the normal phase. However, underlying the rapid increase of the measured mobility in the superfluid phases there is a subtle quantum-mechanical scattering effect. Detailed solutions of the 3 He quasiparticle-negative ion scattering process in the pair-correlated state provide a simple physical picture of an energy-dependent forward-peaking phenomenon. This yields quantitative theoretical results for the ion mobility in the quasi-isotropic B phase and for the ion mobility tensor in the anisotropic A phase which agree with the experimental data. (author)

Phase transition of two-dimensional 3He from a dilute to a dense phase

International Nuclear Information System (INIS)

Bhattacharyya, B.K.; Gasparini, F.M.

1985-01-01

We have measured the heat capacity of 3 He in films of 4 He as thin as 10 A formed on a Nuclepore filter substrate. At low temperatures, where the 3 He is in the lowest state as far as motion perpendicular to the film surface, we find that the 3 He undergoes a transition from a dilute phase to a dense phase. We have observed this transition for films of 4 He of 12.3- and 10-A thickness and for coverages of 3 He below about 0.2 atomic layers. For thicker 4 He films, and higher 3 He coverages, the 3 He remains homogeneously spread out over the surface of the 4 He. The striking characteristic of the transition is the sudden onset of linear temperature dependence with a slope which is proportional to the amount of 3 He in the calorimeter. This is consistent with the formation of islands of a dense two-dimensional phase which grows in extent proportionately to the amount of 3 He. Two puzzling aspects of our results are the lack of a significant heat-capacity jump at the transition and, based on a linear extrapolation of the data to zero temperature, a substantial amount of missing entropy

Measurement of the Target-Normal Single-Spin Asymmetry in Deep-Inelastic Scattering from the Reaction 3He{uparrow}(e,e')X

Energy Technology Data Exchange (ETDEWEB)

Katich, Joseph; Qian, Xin; Zhao, Yuxiang; Allada, Kalyan; Aniol, Konrad; Annand, John; Averett, Todd; Benmokhtar, Fatiha; Bertozzi, William; Bradshaw, Elliott; Bosted, Peter; Camsonne, Alexandre; Canan, Mustafa; Cates, Gordon; Chen, Chunhua; Chen, Jian-Ping; Chen, Wei; Chirapatpimol, Khem; Chudakov, Eugene; Cisbani, Evaristo; Cornejo, Juan; Cusanno, Francesco; Dalton, Mark; Deconinck, Wouter; De Jager, Cornelis; De Leo, Raffaele; Deng, Xiaoyan; Deur, Alexandre; Ding, Huaibo; Dolph, Peter; Dutta, Chiranjib; Dutta, Dipangkar; El Fassi, Lamiaa; Frullani, Salvatore; Gao, Haiyan; Garibaldi, Franco; Gaskell, David; Gilad, Gilad; Gilman, Ronald; Glamazdin, Oleksandr; Golge, Serkan; Guo, Lei; Hamilton, David; Hansen, Jens-Ole; Higinbotham, Douglas; Holmstrom, Timothy; Huang, Jijun; Huang, Min; Ibrahim Abdalla, Hassan; Iodice, Mauro; Jin, Ge; Jones, Mark; Kelleher, Aidan; Kim, Wooyoung; Kolarkar, Ameya; Korsch, Wolfgang; LeRose, John; Li, Xiaomei; Li, Y; Lindgren, Richard; Liyanage, Nilanga; Long, Elena; Lu, Hai-jiang; Margaziotis, Demetrius; Markowitz, Pete; Marrone, Stefano; McNulty, Dustin; Meziani, Zein-Eddine; Michaels, Robert; Moffit, Bryan; Munoz Camacho, Carlos; Nanda, Sirish; Narayan, Amrendra; Nelyubin, Vladimir; Norum, Blaine; Oh, Yoomin; Osipenko, Mikhail; Parno, Diana; Peng, Jen-chieh; Phillips, Sarah; Posik, Matthew; Puckett, Andrew; Qiang, Yi; Rakhman, Abdurahim; Ransome, Ronald; Riordan, Seamus; Saha, Arunava; Sawatzky, Bradley; Schulte, Elaine; Shahinyan, Albert; Hashemi Shabestari, Mitra; Sirca, Simon; Stepanyan, Stepan; Subedi, Ramesh; Sulkosky, Vincent; Tang, Liguang; Tobias, William; Urciuoli, Guido; Vilardi, Ignazio; Wang, Kebin; Wang, Y; Wojtsekhowski, Bogdan; Yan, X; Yao, Huan; Ye, Yunxiu; Ye, Z; Yuan, Lulin; Zhan, Xiaohui; Zhang, Yi; Zhang, Y -W; Zhao, Bo; Zheng, Xiaochao; Zhu, Lingyan; Zhu, Xiaofeng; Zong, Xing

2014-07-01

We report the first measurement of the target single-spin asymmetry in deep-inelastic scattering from the inclusive reaction 3He{uparrow}(e,e')X on a 3He gas target polarized normal to the lepton plane. Assuming time-reversal invariance, this asymmetry is strictly zero in the Born approximation. The experiment, conducted at Jefferson Lab using a 5.89 GeV electron beam, covers a range of 1.7measured proton-to-3He cross section ratios. The measured neutron asymmetries are negative with an average value of (−1.04+/-0.38)×10−2 for invariant mass W>2 GeV, which is non-zero at the 2.75sigma level. Theoretical calculations, which assume two-photon exchange with quasi-free quarks, predict a neutron asymmetry of O(10−4) when both photons couple to one quark, and O(10−2) for the photons coupling to different quarks. Our measured asymmetry agrees both in sign and magnitude with the prediction that uses input based on the Sivers transverse momentum distribution obtained from semi-inclusive deep-inelastic scattering.

{sup 3}He detector analysis of some special shielding materials

Energy Technology Data Exchange (ETDEWEB)

Avdic, S; Pesic, M [Boris Kidric, Institute of Nuclear Sciences, Beograd (Yugoslavia); Marinkovic, P [ETF Belgrade Univ. (Yugoslavia)

1990-07-01

The shielding properties of commercial materials of reactor Experiments, Inc. (R/X) were analyzed at the facility which includes bare heavy water experimental reactor RB with external neutron converter ENC, The fast neutron spectrum measurements in energy range from 1 MeV to 10 MeV was performed using ORTEC semiconductor neutron detector with He{sup 3} in diode coincidence arrangement. The neutron spectra have been evaluated from measured pulse-height distribution using numerical code HE3 for computation of detector efficiency in a collimated neutron beam. The neutron dose rates behind ENC with and without sample R/X material were determined using cubic spline interpolation routine for calculating the corresponding flux-dose rate conversion factors. Satisfactory shielding properties of the examined material in a fast neutron field in measurements and calculations are demonstrated. (author)

Study of Interaction of Low-Energy Antiprotons with H$^{2}$,He$^{3}$,He$^{4}$,Ne-Nuclei Using a Streamer Chamber in Magnetic Field

CERN Multimedia

2002-01-01

The aim of this experiment is the systematic study of the interaction between low-energy antiprotons and the H|2,~He|3,~He|4,~Ne-nuclei using a self shunted streamer chamber in a magnetic field exposed to the antiproton beam of the LEAR facility. The properties of the self shunted streamer chamber, which allows the use of the filling gas (hydrogen, helium, neon at a pressure of l~atm) as a target, permit to carry out experiments also in the very low-energy region. \\\\ \\\\ The experimental apparatus is suitable for a large programme of measurements. We plan to measure the @*H|2 cross section and the spectator momentum distributions at @* momenta lower than 250~MeV/c, where data are lacking. It is interesting to study for the first time the @*He|3 and @*He|4 interactions measuring the cross sections and the emitted particle distributions. Among other things the knowledge of the branching ratio of the @*He|4 annihilation channels clarifies some open cosmological questions. The study of the process of nuclear absor...

π--induced single charge exchange on polarized 3He

International Nuclear Information System (INIS)

Zhao, Q.; Burleson, S.; Blanchard, T.

1995-01-01

Asymmetries, A y , for the (π - ,π 0 ) reaction on polarized 3 He were measured using the pion beam of the P3W channel at LAMPF. The π 0 were detected with the new Neutral Meson Spectrometer (NMS) in coincidence with recoiling tritons. The recoil detector consisted of scintillation-counter telescopes and a wire chamber that provided energy-loss and direction information, respectively. The polarized gaseous 3 He target developed at TRIUMF was modified and run with the use of two diode lasers. Polarizations were typically 50%. The A y taken at T π = 200 MeV between 60 and 105 degrees were found to be strongly angle-dependent. The results will be compared with the theoretical predictions

First doubly polarised photoproduction on 3He at the photon beam of MAMI

International Nuclear Information System (INIS)

Aguar Bartolome, Patricia

2010-11-01

A first experiment with a polarised 3 He target was carried out in July 2009 at the MAMI accelerator in Mainz in a photon energy range between 200 MeV and 800 MeV. The aim of this measurement was to investigate the Gerasimov-Drell-Hearn sum rule on the neutron. The use of the data obtained with the polarised 3 He target, compared to existing data on the deuteron, gives a complementary and more direct access to the neutron, due to the spin structure of the 3 He. The measurement of the helicity dependence of the inclusive total photoabsorption cross section required a beam of tagged circularly polarised photons incident on the longitudinally polarised 3 He target. The data were taken using the 4π Crystal Ball photon spectrometer in combination with TAPS as a forward wall and complemented by a threshold Cherenkov detector used to on-line suppress the background from electromagnetic events. The development and preparation of the different components of the 3 He experimental setup was an important part of this work and are described in detail in this thesis. The detector system and the analysis method were tested by the measurement of the unpolarised total inclusive photoabsorption cross section on liquid hydrogen. The results obtained are in good agreement with previous published data. Preliminary results of the unpolarised total photoabsorption cross section, as well as the helicity dependent photoabsorption cross section difference on 3 He compared with several theoretical models will also be presented. (orig.)

Study of the nuclear structure of 3He by means of polarization observables

International Nuclear Information System (INIS)

Weinriefer, Markus

2011-01-01

With the possibility to measure several polarization degrees of freedom in the quasi-elastic electron scattering of 3 He is a new way to access small, but important partial wave contributions (S ' , D-wave) to the 3 He ground state. This gives direct access to a better understanding of the three-body-system. It also opens up a way to directly test the 3 He structure and dynamics. With this information it is possible to test ab initio calculations and to calculate corrections that are needed for different experiments (measurement of G en for example). Modern Faddeev-calculations do not only give a quantitative description of the 3 He ground state. They also give insight in so called spin dependent momentum distributions. A systematic experimental investigation is needed to get a good basis for tests of the theoretical models. A triple-polarization-experiment can give important data in this field. Also with the help of such an experiment one can investigate if polarized 3 He can be used as an effective polarized proton target by the method of ''deuteron-tagging''. The experiment presented in this work combines for the first time beam- and target-polarization as well as a measurement of the polarization of the outgoing proton. The measurement was done in summer of 2007 at the three spectrometer setup of the A1 collaboration at the MAMI accelerator. A beam energy of E=855 MeV was used and we measured at q 2 =-0.14 (GeV/c) 2 (ω=0.13 GeV, q=0.4 GeV/c). The measured cross section, as well as the beam-target- and triple-asymmetry were compared to a theoretical calculation by J. Golak (he gives a plane wave impulse approximation (PWIA) calculation and a calculation also taking final state interaction into account). The cross section was also compared to a model by de Forest that is using a measured spectral function. The comparison shows a good agreement between the measured cross section as well as the double and triple asymmetry and the theoretical calculations. The

Spin effects in medium-energy electron-3He scattering

International Nuclear Information System (INIS)

van den Brand, J.F.J.; Alarcon, R.; Bauer, T.

1998-01-01

New physics can be accessed by scattering polarized electrons from a polarized 3 He internal gas target. It is discussed how the asymmetries for the reactions 3 vector He(vector e,e'), 3 vector He(vector e,e'p), 3 vector He(vector e,e'n), 3 vector He(vector e,e'd), and 3 vector He(vector e,e'pn) may provide precise information on the S' and the D-wave parts of the 3 He ground-state wave function, the neutron form factors, and the role of spin-dependent reaction mechanism effects. The experiment uses up to 900 MeV (polarized) electrons from the AmPS storage ring in Amsterdam, Netherlands, in combination with large acceptance electron and hadron detectors. (orig.)

Goal-Oriented Self-Adaptive hp Finite Element Simulation of 3D DC Borehole Resistivity Simulations

KAUST Repository

Calo, Victor M.; Pardo, David; Paszyński, Maciej R.

2011-01-01

(adjusting polynomial orders of approximation) or hp (both) refinements on the finite elements. The new parallel implementation utilizes a computational mesh shared between multiple processors. All computational algorithms, including automatic hp goal

Development of sample assay system equipped with 3He Alternative Neutron Detectors (ASAS). (2) Results of ASAS measurement test

International Nuclear Information System (INIS)

Tanigawa, Masafumi; Mukai, Yasunobu; Kurita, Tsutomu; Makino, Risa; Nakamura, Hironobu; Tobita, Hiroshi; Ohzu, Akira; Kureta, Masatoshi; Seya, Michio

2015-01-01

Against the background of the serious shortage of 3 He gas, design and development of a new detector equipped ZnS/ 10 B 2 O 3 ceramic scintillation neutron detectors in JAEA, with the support of the government (the Ministry of Education, Culture, Sports, Science and Technology). The design of the alternative 3 He detector is referred from INVS (INVentory Sample assay system (HLNCC (High Level Neutron Coincidence Counter) type)) which is being used for the verification of MOX powder etc. and is named it as ASAS (Alternative Sample Assay System). In order to prove the Pu quantitative performance as an alternative technology, several measurement tests and comparison test with INVS were conducted using ASAS. In these tests, evaluation of fundamental performance (counting efficiency and die-away time) and uncertainty evaluations were implemented. As a result, although fundamental performance of ASAS was not achieved to the one of INVS, we could confirm that ASAS has almost the same Pu quantitative performance including measurement uncertainty as that of INVS. (author)

First measurement of the electric formfactor of the neutron in the exclusive quasielastic scattering of polarized electrons from polarized 3He

International Nuclear Information System (INIS)

Meyerhoff, M.; Eyl, D.; Frey, A.; Andresen, H.G.; Annand, J.R.M.; Aulenbacher, K.; Becker, J.; Blume-Werry, J.; Dombo, T.; Drescher, P.; Ducret, J.E.; Fischer, H.; Grabmayr, P.; Hall, S.; Hartmann, P.; Hehl, T.; Heil, W.; Hoffmann, J.; Kellie, J.D.; Klein, F.; Leduc, M.; Moeller, H.; Nachtigall, C.; Ostrick, M.; Otten, E.W.; Owens, R.O.; Pluetzer, S.; Reichert, E.; Rohe, D.; Schaefer, M.; Schearer, L.D.; Schmieden, H.; Steffens, K.; Surkau, R.; Walcher, T.

1995-01-01

A first measurement of the asymmetry in quasielastic scattering of longitudinally polarized electrons from a polarized 3 He gas target in coincidence with the knocked out neutron is reported. This measurement was made feasible by the cw beam of the 855 meV Mainz Microtron MAMI. It allows a determination of the electric formfactor of the neutron G n E independent of binding effects to first order. At bar Q 2 =0.31 (GeV/c) 2 two asymmetries bar A parallel (rvec S He parallel rvec q) and bar A perpendicular (rvec S He perpendicular rvec q) have been measured giving bar A parallel =(-7.40±0.73%) and bar A perpendicular =(0.89±0.30)%. The ratio bar A perpendicular /bar A parallel is independent of the absolute value of the electron and target polarization and yields G n E =0.035±0.012±0.005. copyright 1995 American Institute of Physics

Hard Two-Body Photodisintegration of He3

Science.gov (United States)

Pomerantz, I.; Ilieva, Y.; Gilman, R.; Higinbotham, D. W.; Piasetzky, E.; Strauch, S.; Adhikari, K. P.; Aghasyan, M.; Allada, K.; Amaryan, M. J.; Anefalos Pereira, S.; Anghinolfi, M.; Baghdasaryan, H.; Ball, J.; Baltzell, N. A.; Battaglieri, M.; Batourine, V.; Beck, A.; Beck, S.; Bedlinskiy, I.; Berman, B. L.; Biselli, A. S.; Boeglin, W.; Bono, J.; Bookwalter, C.; Boiarinov, S.; Briscoe, W. J.; Brooks, W. K.; Bubis, N.; Burkert, V.; Camsonne, A.; Canan, M.; Carman, D. S.; Celentano, A.; Chandavar, S.; Charles, G.; Chirapatpimol, K.; Cisbani, E.; Cole, P. L.; Contalbrigo, M.; Crede, V.; Cusanno, F.; D'Angelo, A.; Daniel, A.; Dashyan, N.; de Jager, C. W.; De Vita, R.; De Sanctis, E.; Deur, A.; Djalali, C.; Dodge, G. E.; Doughty, D.; Dupre, R.; Dutta, C.; Egiyan, H.; El Alaoui, A.; El Fassi, L.; Eugenio, P.; Fedotov, G.; Fegan, S.; Fleming, J. A.; Fradi, A.; Garibaldi, F.; Geagla, O.; Gevorgyan, N.; Giovanetti, K. L.; Girod, F. X.; Glister, J.; Goetz, J. T.; Gohn, W.; Golovatch, E.; Gothe, R. W.; Griffioen, K. A.; Guegan, B.; Guidal, M.; Guo, L.; Hafidi, K.; Hakobyan, H.; Harrison, N.; Heddle, D.; Hicks, K.; Ho, D.; Holtrop, M.; Hyde, C. E.; Ireland, D. G.; Ishkhanov, B. S.; Isupov, E. L.; Jiang, X.; Jo, H. S.; Joo, K.; Katramatou, A. T.; Keller, D.; Khandaker, M.; Khetarpal, P.; Khrosinkova, E.; Kim, A.; Kim, W.; Klein, F. J.; Koirala, S.; Kubarovsky, A.; Kubarovsky, V.; Kuleshov, S. V.; Kvaltine, N. D.; Lee, B.; LeRose, J. J.; Lewis, S.; Lindgren, R.; Livingston, K.; Lu, H. Y.; MacGregor, I. J. D.; Mao, Y.; Martinez, D.; Mayer, M.; McCullough, E.; McKinnon, B.; Meekins, D.; Meyer, C. A.; Michaels, R.; Mineeva, T.; Mirazita, M.; Moffit, B.; Mokeev, V.; Montgomery, R. A.; Moutarde, H.; Munevar, E.; Munoz Camacho, C.; Nadel-Turonski, P.; Nasseripour, R.; Nepali, C. S.; Niccolai, S.; Niculescu, G.; Niculescu, I.; Osipenko, M.; Ostrovidov, A. I.; Pappalardo, L. L.; Paremuzyan, R.; Park, K.; Park, S.; Petratos, G. G.; Phelps, E.; Pisano, S.; Pogorelko, O.; Pozdniakov, S.; Procureur, S.; Protopopescu, D.; Puckett, A. J. R.; Qian, X.; Qiang, Y.; Ricco, G.; Rimal, D.; Ripani, M.; Ritchie, B. G.; Rodriguez, I.; Ron, G.; Rosner, G.; Rossi, P.; Sabatié, F.; Saha, A.; Saini, M. S.; Sarty, A. J.; Sawatzky, B.; Saylor, N. A.; Schott, D.; Schulte, E.; Schumacher, R. A.; Seder, E.; Seraydaryan, H.; Shneor, R.; Smith, G. D.; Sokhan, D.; Sparveris, N.; Stepanyan, S. S.; Stepanyan, S.; Stoler, P.; Subedi, R.; Sulkosky, V.; Taiuti, M.; Tang, W.; Taylor, C. E.; Tkachenko, S.; Ungaro, M.; Vernarsky, B.; Vineyard, M. F.; Voskanyan, H.; Voutier, E.; Walford, N. K.; Wang, Y.; Watts, D. P.; Weinstein, L. B.; Weygand, D. P.; Wojtsekhowski, B.; Wood, M. H.; Yan, X.; Yao, H.; Zachariou, N.; Zhan, X.; Zhang, J.; Zhao, Z. W.; Zheng, X.; Zonta, I.

2013-06-01

We have measured cross sections for the γHe3→pd reaction at photon energies of 0.4-1.4 GeV and a center-of-mass angle of 90°. We observe dimensional scaling above 0.7 GeV at this center-of-mass angle. This is the first observation of dimensional scaling in the photodisintegration of a nucleus heavier than the deuteron.

Hard two-body photodisintegration of 3He.

Science.gov (United States)

Pomerantz, I; Ilieva, Y; Gilman, R; Higinbotham, D W; Piasetzky, E; Strauch, S; Adhikari, K P; Aghasyan, M; Allada, K; Amaryan, M J; Anefalos Pereira, S; Anghinolfi, M; Baghdasaryan, H; Ball, J; Baltzell, N A; Battaglieri, M; Batourine, V; Beck, A; Beck, S; Bedlinskiy, I; Berman, B L; Biselli, A S; Boeglin, W; Bono, J; Bookwalter, C; Boiarinov, S; Briscoe, W J; Brooks, W K; Bubis, N; Burkert, V; Camsonne, A; Canan, M; Carman, D S; Celentano, A; Chandavar, S; Charles, G; Chirapatpimol, K; Cisbani, E; Cole, P L; Contalbrigo, M; Crede, V; Cusanno, F; D'Angelo, A; Daniel, A; Dashyan, N; de Jager, C W; De Vita, R; De Sanctis, E; Deur, A; Djalali, C; Dodge, G E; Doughty, D; Dupre, R; Dutta, C; Egiyan, H; El Alaoui, A; El Fassi, L; Eugenio, P; Fedotov, G; Fegan, S; Fleming, J A; Fradi, A; Garibaldi, F; Geagla, O; Gevorgyan, N; Giovanetti, K L; Girod, F X; Glister, J; Goetz, J T; Gohn, W; Golovatch, E; Gothe, R W; Griffioen, K A; Guegan, B; Guidal, M; Guo, L; Hafidi, K; Hakobyan, H; Harrison, N; Heddle, D; Hicks, K; Ho, D; Holtrop, M; Hyde, C E; Ireland, D G; Ishkhanov, B S; Isupov, E L; Jiang, X; Jo, H S; Joo, K; Katramatou, A T; Keller, D; Khandaker, M; Khetarpal, P; Khrosinkova, E; Kim, A; Kim, W; Klein, F J; Koirala, S; Kubarovsky, A; Kubarovsky, V; Kuleshov, S V; Kvaltine, N D; Lee, B; LeRose, J J; Lewis, S; Lindgren, R; Livingston, K; Lu, H Y; MacGregor, I J D; Mao, Y; Martinez, D; Mayer, M; McCullough, E; McKinnon, B; Meekins, D; Meyer, C A; Michaels, R; Mineeva, T; Mirazita, M; Moffit, B; Mokeev, V; Montgomery, R A; Moutarde, H; Munevar, E; Munoz Camacho, C; Nadel-Turonski, P; Nasseripour, R; Nepali, C S; Niccolai, S; Niculescu, G; Niculescu, I; Osipenko, M; Ostrovidov, A I; Pappalardo, L L; Paremuzyan, R; Park, K; Park, S; Petratos, G G; Phelps, E; Pisano, S; Pogorelko, O; Pozdniakov, S; Procureur, S; Protopopescu, D; Puckett, A J R; Qian, X; Qiang, Y; Ricco, G; Rimal, D; Ripani, M; Ritchie, B G; Rodriguez, I; Ron, G; Rosner, G; Rossi, P; Sabatié, F; Saha, A; Saini, M S; Sarty, A J; Sawatzky, B; Saylor, N A; Schott, D; Schulte, E; Schumacher, R A; Seder, E; Seraydaryan, H; Shneor, R; Smith, G D; Sokhan, D; Sparveris, N; Stepanyan, S S; Stepanyan, S; Stoler, P; Subedi, R; Sulkosky, V; Taiuti, M; Tang, W; Taylor, C E; Tkachenko, S; Ungaro, M; Vernarsky, B; Vineyard, M F; Voskanyan, H; Voutier, E; Walford, N K; Wang, Y; Watts, D P; Weinstein, L B; Weygand, D P; Wojtsekhowski, B; Wood, M H; Yan, X; Yao, H; Zachariou, N; Zhan, X; Zhang, J; Zhao, Z W; Zheng, X; Zonta, I

2013-06-14

We have measured cross sections for the γ(3)He → pd reaction at photon energies of 0.4-1.4 GeV and a center-of-mass angle of 90°. We observe dimensional scaling above 0.7 GeV at this center-of-mass angle. This is the first observation of dimensional scaling in the photodisintegration of a nucleus heavier than the deuteron.

HP Ge planar detectors

International Nuclear Information System (INIS)

Gornov, M.G.; Gurov, Yu.B.; Soldatov, A.M.; Osipenko, B.P.; Yurkowski, J.; Podkopaev, O.I.

1989-01-01

Parameters of planar detectors manufactured of HP Ge are presented. The possibilities to use multilayer spectrometers on the base of such semiconductor detectors for nuclear physics experiments are discussed. It is shown that the obtained detectors including high square ones have spectrometrical characteristics close to limiting possible values. 9 refs.; 3 figs.; 1 tab

75 FR 62424 - EDS, an HP Company (Re-Branded as HP-Enterprise Services) Including On-Site Workers From: Abel...

Science.gov (United States)

2010-10-08

...-Branded as HP--Enterprise Services) Including On-Site Workers From: Abel Personnel Inc., Advantage Tech... February 4, 2010, applicable to workers of EDS, an HP Company (Re- branded as HP--Enterprise Services...-branded as HP-- Enterprise Services). These employees provided various activities related to the supply of...

A novel particle time of flight diagnostic for measurements of shock- and compression-bang times in D3He and DT implosions at the NIF.

Science.gov (United States)

Rinderknecht, H G; Johnson, M Gatu; Zylstra, A B; Sinenian, N; Rosenberg, M J; Frenje, J A; Waugh, C J; Li, C K; Sèguin, F H; Petrasso, R D; Rygg, J R; Kimbrough, J R; MacPhee, A; Collins, G W; Hicks, D; Mackinnon, A; Bell, P; Bionta, R; Clancy, T; Zacharias, R; Döppner, T; Park, H S; LePape, S; Landen, O; Meezan, N; Moses, E I; Glebov, V U; Stoeckl, C; Sangster, T C; Olson, R; Kline, J; Kilkenny, J

2012-10-01

The particle-time-of-flight (pTOF) diagnostic, fielded alongside a wedge range-filter (WRF) proton spectrometer, will provide an absolute timing for the shock-burn weighted ρR measurements that will validate the modeling of implosion dynamics at the National Ignition Facility (NIF). In the first phase of the project, pTOF has recorded accurate bang times in cryogenic DT, DT exploding pusher, and D(3)He implosions using DD or DT neutrons with an accuracy better than ±70 ps. In the second phase of the project, a deflecting magnet will be incorporated into the pTOF design for simultaneous measurements of shock- and compression-bang times in D(3)He-filled surrogate implosions using D(3)He protons and DD-neutrons, respectively.

The intercomparison of 137Cs irradiator output measurement and personal dose equivalent, Hp(10), using TLD and film

International Nuclear Information System (INIS)

Nazaroh; Susetyo Trijoko; Sri Inang Sunaryati

2010-01-01

Intercomparison of output measurement of 137 Cs irradiator and personal dose equivalent, Hp(10) using TLD and film have been carried out in the year of 2006 to 2008. According to IAEA recommendation, intercomparison is one of audit activities but it is performed in the spirit of collaboration and support rather than in the spirit of inspection. The aim of intercomparison of output measurement of 137 Cs irradiator is to verify the dose stated by the participant laboratories. Intercomparison is also to assess the competency of the participant, to keep traceability and consistency of measurement result, to assure that instrument work correctly and the result of evaluation was in agreement, and also for fulfilling one of the clauses of ISO-17025-2005. Besides that, this intercomparison aimed to facilitate link between the system and members of national measurement and transfer of experience in measurement technique and dose evaluation of radiation. The benefit of intercomparison is important among others as tests of proficiency in dose evaluation or measurement, upgrading quality of service and for obeying supervisor body legislation (BAPETEN). TLD was used as a means of output 137 Cs irradiator measurement, whereas film and TLD were used for dose intercomparison. This paper presented result of intercomparison of output measurement and evaluation of personal dose equivalent, Hp(10) in the year of 2006 to 2008 followed by 6 participants: Balai Pengamanan Fasilitas Kesehatan (BPFK) Jakarta, Medan, Surabaya, Makasar, PTLR and Laboratory of Keselamatan dan Kesehatan Lingkungan (KKL)-PTKMR BATAN. In this intercomparison, the dose of TLD stated by participant were compared with the dose measured by Radiation Metrology Laboratory (LMR), and the results showed the differences were within 10 %, so it was satisfied. The results of intercomparison of personal dose equivalent, Hp(10) were evaluated based on ISO/IEC Guide 43-1, 1997 analysis and expressed as E n . The values of E n

Experimental study and nuclear model calculations of {sup 3}He-induced nuclear reactions on zinc

Energy Technology Data Exchange (ETDEWEB)

Al-Abyad, M.; Mohamed, Gehan Y. [Nuclear Research Centre, Atomic Energy Authority, Physics Department (Cyclotron Facility), Cairo (Egypt); Ditroi, F.; Takacs, S.; Tarkanyi, F. [Hungarian Academy of Sciences (ATOMKI), Institute for Nuclear Research, Debrecen (Hungary)

2017-05-15

Excitation functions of {sup 3}He-induced nuclear reactions on natural zinc were measured using the standard stacked-foil technique and high-resolution gamma-ray spectrometry. From their threshold energies up to 27 MeV, the cross-sections for {sup nat}Zn ({sup 3}He,xn) {sup 69}Ge, {sup nat}Zn({sup 3}He,xnp) {sup 66,67,68}Ga, and {sup nat}Zn({sup 3}He,x){sup 62,65}Zn reactions were measured. The nuclear model codes TALYS-1.6, EMPIRE-3.2 and ALICE-IPPE were used to describe the formation of these products. The present data were compared with the theoretical results and with the available experimental data. Integral yields for some important radioisotopes were determined. (orig.)

Contactless friction and the {sup 3}He-{sup 4}He dimer. Studies with the atomic-beam spin-echo spectrometer; Kontaktlose Reibung und das {sup 3}He-{sup 4}He-Dimer. Untersuchungen mit dem Atomstrahlspinechospektrometer

Energy Technology Data Exchange (ETDEWEB)

Janke, Matthias

2016-04-20

In this thesis the time of flight resolved atomic beam spin echo method (SEToF) is applied to a {sup 3}He-beam for the first time and studied systematically. This method is shown to be superior to the usual atomic beam spin echo technique. With SEToF it is possible to almost completely remove unpolarized background and to reach a beam polarisation close to 100%. The SEToF technique is shown to be crucial for the first experimental proof of the existence of the {sup 3}He-{sup 4}He dimer. This dimer is the weakest bound van-der-Waals-molecule known to date. Furthermore, a drag force between an atom and a dielectric surface is detected originating from the fluctuating dipole moment of the atom. Not only the measured friction coefficients match their theoretical predictions perfectly, but our data also shows the correct temperature dependence. A great many technological renewals and improvements were installed in the apparatus during this thesis work. They have become necessary or sensible due to the relocation of the physics institute. A few of them are documented and motivated in this thesis.

Nonlinear second- and first-sound wave equations in 3He-4He mixtures

International Nuclear Information System (INIS)

Mohazzab, Masoud; Mulders, Norbert

2000-01-01

We derive nonlinear Burgers equations for first and second sound in mixtures of 3 He- 4 He, using a reductive perturbation method and obtain expressions for the nonlinear and dissipation coefficients. We further find a diffusion equation for a coupled temperature-concentration mode. The amplitude of first (second) sound generated from second (first) sound in mixtures is also derived. Our derivation includes the dependence of thermodynamical quantities on temperature, pressure, and 3 He concentration, and is valid up to a first order in terms of the isobaric expansion coefficient. We show that close to the λ line the nonlinearity of second sound in mixtures is enhanced as compared with pure 4 He

Measurement of the distributions of internuclear separations in 3.0-MeV H2+ and 3.63-MeV HeH+ beams

International Nuclear Information System (INIS)

Kanter, E.P.; Cooney, P.J.; Gemmell, D.S.; Vager, Z.; Pietsch, W.J.; Zabransky, B.J.

1979-01-01

Angular distributions of charged dissociation fragments are measured for 3.0-MeV H 2 + and 3.63-MeV HeH + ions incident on approx. 160 A carbon targets. By using the reflection method for a pure Coulomb potential, there are unfolded from these data the distributions of internuclear separations for each molecular-ion species prior to dissociation. These results are insensitive to ion-source conditions. For H 2 + this distribution, while approx. 2 times wider than a pure ground vibrational state population, is markedly different from the Franck-Condon distribution that has been previously assumed by other authors with similar rf and duo-plasmatron ion sources. For HeH + the distribution is slightly broader (approx. 1.5 times) than that expected for a pure ground state population. From the data, the initial vibrational state population in the incident beam can be extracted. 11 references

Realization of a broad band neutron spin filter with compressed, polarized 3He gas

International Nuclear Information System (INIS)

Surkau, R.; Otten, E.W.; Steiner, M.; Tasset, F.; Trautmann, N.

1997-01-01

The strongly spin dependent absorption of neutrons in nuclear spin polarized 3 -2pt vector He opens the possibility to polarize beams of thermal and epithermal neutrons. An effective 3 He neutron spin filter (NSF) requires high 3 He nuclear polarization as well as a filter thickness corresponding to a gas amount of the order of 1 bar l. We realized such a filter using direct optical pumping of metastable 3 He * atoms in a 3 He plasma at 1 mbar. Metastable exchange scattering transfers the angular momentum to the whole ensemble of 3 He atoms. At present 3 x 10 18 3 He-atoms/s are polarized up to 64%. Subsequent polarization preserving compression by a two stage compressor system enables to prepare NSF cells of about 300 cm 3 volume with 3 bar of polarized 3 He within 2 h. 3 He polarizations up to 53% were measured in a cell with a filter length of about 15 cm. By this cell a thermal neutron beam from the Mainz TRIGA reactor was polarized. A wavelength selective polarization analysis by means of Bragg scattering revealed a neutron polarization of 84% at a total transmission of 12% for a neutron wavelength of 1 A. (orig.)

Pion absorption in flight on 3He

International Nuclear Information System (INIS)

Ljungfelt, S.H.

1985-02-01

Pion absorption in flight on 3 He has been measured in a kinematically complete manner. The experiment was done in the πE1-channel at the Swiss Institute for Nuclear Research, SIN, using π + - and π - -beams of 120 and 165 MeV kinetic energy. Two of the emitted particles were measured in coincidence and identified by their time-of-flight/pulseheight relation. The obtained two-dimensional energy representation enabled a separation of the different kinematical regions and exhibited a clear enhancement in the region of quasifree absorption, QFA. (orig./WL)

Backward elastic p3He-scattering and high momentum components of 3He wave function

International Nuclear Information System (INIS)

Uzikov, Yu.N.

1998-01-01

It is shown that owing to a dominance of np-pair transfer mechanism of backward elastic p 3 He-scattering for incident proton kinetic energies T p > 1 GeV the cross section of this process is defined mainly by the values of the Faddeev component of the wave function of 3 He nucleus, φ 23 (q 23 , p 1 ), at high relative momenta q 23 > 0.6 GeV/c of the NN-pair in the 1 S 0 -state and at low spectator momenta p 1 ∼ 0 - 0.2 GeV/c

Electric dipole moment of 3He

International Nuclear Information System (INIS)

Avishai, Y.; Fabre de la Ripelle, M.

1987-01-01

The contribution of CP violating nucleon-nucleon interaction to the electric dipole moment of 3 He is evaluated following a recent proposal for its experimental detection. Two models of CP violating interactions are used, namely, the Kobayashi-Maskawa mechanism and the occurrence of the Θ term in the QCD lagrangian. These CP violating interactions are combined with realistic strong nucleon-nucleon interactions to induce a CP forbidden component of the 3 He wave function. The matrix element of the electric dipole operator is then evaluated between CP allowed and CP forbidden components yielding the observable electric dipole moment. Using the parameters emerging from the penguin terms in the Kobaysashi-Maskawa model we obtain a result much larger than the electric dipole moment of the neutron in the same model. On the other hand, no enhancement is found for the Θ-term mechanism. A possible explanation for this difference is discussed. Numerical estimates can be given only in the Kobayashi-Maskawa model, giving d( 3 He) ≅ 10 30 e . cm. In the second mechanism, the estimate give d ( 3 He) ≅ 10 16 anti Θ. (orig.)

Mass spectrometer determinations of solar wind He, Ne, and Ar and radiation belt He

International Nuclear Information System (INIS)

Warasila, R.L.

1976-01-01

A unique mass spectrometer system was built and used to measure He, Ne, and Ar abundances and isotopic ratios in various samples of spacecraft that have been exposed to the space environment. The Apollo 12 mission brought back sections of the Surveyor 3 vehicle suitable for mass spectrometric studies of implanted solar wind and solar cosmic ray particles. Using the mass spectrometer, a 4 He flux of 6-8 x 10 6 ions/cm 2 --sec was measured, and in addition 4 He/ 3 He = 2700 +- 50; 4 He/ 20 Ne = 410 + 30; 20 Ne/ 22 Ne = 13.5 +- 0.2; 20 Ne/ 36 Ar = 24.5 +- 2.5; and 36 Ar/ 38 Ar = 5.41 +- 0.20 isotopic abundances were measured. An upper limit for the flux of SCR 3 He in the 10-20 MeV/nucleon range was also determined, for the thirty-one month exposure period. In the radiation belt environment, 3 He was found in the aluminum antenna housing from the recovered second stage of a pre-Apollo Saturn test flight launched January 28, 1964 and returned to earth on April 28, 1966. The amount of 3 He found was about 6 x 10 -10 cc(STP)/cm 2 with a 4 He/ 3 He ratio of 145 or less. The 3 He was shown to come from the lower radiation belt as all other sources of 3 He were orders of magnitude lower than the observed value

Pion production in 3He-nucleus interactions at 910 MeV

International Nuclear Information System (INIS)

Aslanides, E.; Baumann, P.; Bergdolt, G.; Engelstein, P.; Fassnacht, P.; Hibou, F.; Bressani, T.; Puddu, G.A.

1983-01-01

The ( 3 He, πsup(+-)X) reaction has been studied at 910 MeV using the 3 He ++ beam of the CERN SC, Complete π - spectra on CH 2 , CD 2 , 9 Be, 12 C, 27 Al, Cd and Pb, and π + spectra on CH 2 , CD 2 and 12 C targets have been measured at 0 0 , up or close to the kinematic limit xsub(F)=1. The results are compared to various theoretical calculations. (orig.)

Specific features of kinetics of He3-He4 solid solution transformations at superlow temperatures

International Nuclear Information System (INIS)

Mikheev, V.A.; Majdanov, V.A.; Mikhin, N.P.

1986-01-01

The NMR data on the phase transition kinetics of 3 He- 4 He solid solutions at T=100 mK are considered. Studied are solid helium samples of a molecular volume of 20.55 cm 2 /mol with a 3 He content of 0.54 %. An unusually long phase transition time is found which is dependent on the prehistory of sample. The spin diffusion of 3 He in the transformated solution concentrated phase is found to be of a quasi-one-dimensional nature with the diffusion coefficient value typical of liquid

Specific features of concentrated phase under decomposition of weak solid /sup 3/He-/sup 4/He solution

Energy Technology Data Exchange (ETDEWEB)

Mikheev, V A; Majdamov, V A; Kal' noj, S E; Omelaenko, N I

1988-06-01

The decomposition of solid /sup 3/He-/sup 4/He solutuions is studied on the samples 0.54% /sup 3/He(V=20.55 cm/sup 3//mole) and 0.60% /sup 4/He (V=24.04-24.93 cm/sup 3//mole) using pulse NMR method. At T=100 mK the decomposition of a weak solution proceeds more than for 30 h, the decomposition rate and temperature being dependent on the sample prehistory. In the concentrated phase of the decomposed weak solution the spin diffraction of /sup 3/He is of the quasi-one-dimensional character with the diffusion coefficient D /similar to/ 10/sup -5/ cm/sup 2//sec typical of liquid /sup 3/He and exceeding that bulk solid /sup 3/He by two orders of magnitude. The longitudinal relaxation time in the quasi-one-dimensional phase (/similar to/ 1 sec) is characteristic of the solid state and coinsides with data for bulk /sup 3/He. The temperature behaviour of magnetization in the quasi-one-dimensional phase is well described by the Curie law.

Spin polarized 3He: a ''new'' quantum fluid

International Nuclear Information System (INIS)

Lhuillier, C.; Laloe, F.

1979-01-01

The physical properties of a 3 He fluid are studied, in which all nuclear spins are parallel to each other (fully polarized 3 He). At low temperatures, significant differences can exist between this polarized fluid and normal 3 He. The origin of these differences is purely quantum mechanical and arises from the Pauli exclusion principle. At low densities, only the transport properties of the gas are modified. At higher densities. The equilibrium properties (virial coefficients) are also changed by the nuclear polarization. Changes of the liquid-vapour or liquid-solid equilibrium pressures, as well as modifications of the 3 He- 4 He mixture phase diagram are predicted. This article gives a preliminary theoretical study of these new effects. Experimental prospects are briefly discussed [fr

Three-critical phenomena in the He3-He4 mixture

International Nuclear Information System (INIS)

Carvalho Filho, C.A.A. de.

1976-07-01

A review of the phenomenology of tricritical behaviour in He 3 -He 4 mixtures is made. Starting from a model proposed by Blume, Emery and Griffiths the tricritical transition is investigated by means of the Renormalization Group making use of the Callan-Symanzik equation and usual perturbative methods of Relativistic Quantum Field Theory. Mean-field tricritical exponents and logarithmic corrections are found in a sup(n) unified context. The structure of scaling laws is also studied. (author) [pt

Measurement of the 2H(7Be, 6Li)3He reaction rate and its contribution to the primordial lithium abundance

Science.gov (United States)

Li, Er-Tao; Li, Zhi-Hong; Yan, Sheng-Quan; Su, Jun; Guo, Bing; Li, Yun-Ju; Wang, You-Bao; Lian, Gang; Zeng, Sheng; Chen, Si-Zhe; Ma, Shao-Bo; Li, Xiang-Qing; He, Cao; Sun, Hui-Bin; Liu, Wei-Ping

2018-04-01

In the standard Big Bang nucleosynthesis (SBBN) model, the lithium puzzle has attracted intense interest over the past few decades, but still has not been solved. Conventionally, the approach is to include more reactions flowing into or out of lithium, and study the potential effects of those reactions which were not previously considered. 7Be(d, 3He)6Li is a reaction that not only produces 6Li but also destroys 7Be, which decays to 7Li, thereby affecting 7Li indirectly. Therefore, this reaction could alleviate the lithium discrepancy if its reaction rate is sufficiently high. However, there is not much information available about the 7Be(d, 3He)6Li reaction rate. In this work, the angular distributions of the 7Be(d, 3He)6Li reaction are measured at the center of mass energies E cm = 4.0 MeV and 6.7 MeV with secondary 7Be beams for the first time. The excitation function of the 7Be(d, 3He)6Li reaction is first calculated with the computer code TALYS and then normalized to the experimental data, then its reaction rate is deduced. A SBBN network calculation is performed to investigate its influence on the 6Li and 7Li abundances. The results show that the 7Be(d, 3He)6Li reaction has a minimal effect on 6Li and 7Li because of its small reaction rate. Therefore, the 7Be(d, 3He)6Li reaction is ruled out by this experiment as a means of alleviating the lithium discrepancy. Supported by National Natural Science Foundation of China (11375269, 11505117, 11490560, 11475264, 11321064), Natural Science Foundation of Guangdong Province (2015A030310012), 973 program of China (2013CB834406) and National key Research and Development Province (2016YFA0400502)

3He functions in tokamak-pumped laser systems

International Nuclear Information System (INIS)

Jassby, D.L.

1986-10-01

3 He placed in an annular cell around a tokamak fusion generator can convert moderated fusion neutrons to energetic ions by the 3 He(n,p)T reaction, and thereby excite gaseous lasants mixed with the 3 He while simultaneously breeding tritium. The total 3 He inventory is about 4 kg for large tokamak devices. Special configurations of toroidal-field magnets, neutron moderators and beryllium reflectors are required to permit nearly uniform neutron current into the laser cell with minimal attenuation. The annular laser radiation can be combined into a single output beam at the top of the tokamak

Survey of the (3He,t) reaction: Excitation of the isobaric analog of the giant dipole resonance

International Nuclear Information System (INIS)

Tabor, S.L.; Chang, C.C.; Collins, M.T.; Wagner, G.J.; Wu, J.R.; Halderson, D.W.; Petrovich, F.

1982-01-01

The ( 3 He,t) reaction at 130 and 170 MeV has been investigated on targets of 12 C, 16 O, 27 Al, 28 Si, 40 Ca, 46 Ti, and 90 Zr. Data for the ( 3 He, 3 He') reaction were measured simultaneously for reference purposes. Structure is observed in the spectra from the ( 3 He, 3 He') and ( 3 He,t) reaction at the expected positions of the giant quadrupole resonance and the isobaric analog of the giant dipole resonance, respectively. An angular distribution was measured for the suspected giant dipole resonance structure in the 40 Ca( 3 He,t) 40 Sc reaction at 130 MeV. The data are reasonably described by a collective model calculation based on the Goldhaber-Teller model for the giant dipole resonance. Several other strong peaks at excitation energies below the giant dipole resonance are observed in the ( 3 He,t) spectra. Most notable of these are the ones at the expected positions for analogs of well known 1 + states and 1hω stretched states in the targets

3He release characteristics of metal tritides and scandium--tritium solid solutions

International Nuclear Information System (INIS)

Perkins, W.G.; Kass, W.J.; Beavis, L.C.

1976-01-01

Tritides of such metals as Sc, Ti, and Er are useful materials for determining the effects of He accumulation in metallic solids, for example, CTR first wall materials. Such effects include lattice strain and gross deformation which are related to 3 He retention and ultimate release. Long term gas release studies have indicated that, during the early life of a metal ditritide, a large fraction of the 3 He is retained in the solid. At more advanced ages, the 3 He release rate becomes comparable to the generation rate. Statistical analysis of the data indicates that the acceleration in 3 He release rate depends on accumulated 3 He concentration rather than strictly on age. 3 He outgassing results are presented for thin films of ScT 2 , TiT 2 , and ErT 2 , and the critical 3 He concentrations are discussed in terms of a percolation model. Phase transformations which occur on tritide formation cast some doubt on the validity of extrapolating results obtained for metal tritides to predictions regarding the accumulation of helium in metals. Sc is unique among the early transition and rare-earth metals in that the metal exhibits a very high room temperature T solubility (T/Sc = 0.4) with no phase transformation. Indeed, even the lattice parameters of the hcp Sc lattice are only minimally changed by T solution. Single crystal ScT/sub 0.3/ samples in two crystallographic orientations were obtained. Using a very sensitive technique, 3 He emission was measured from both these samples, as well as from fine-grained thin film Sc--T solid solution samples (ScT/sub 0.3-0.4/). The fine-grained film samples release 3 He at 2-3 percent of the generation rate, while the emission rate from the single-crystal samples is approximately 0.05 percent of the generation rate, indicating a strong grain size effect

The (3He,α) reaction mechanism. A study of the angular momentum transfer

International Nuclear Information System (INIS)

Guttormsen, M.; Bergholt, L.; Ingebretsen, F.; Loevhoeiden, G.; Messelt, S.; Rekstad, J.; Tveter, T.S.; Helstrup, H.; Thorsteinsen, T.F.

1994-01-01

The γ-rays emitted after the 163 Dy( 3 He,αxn) reactions at E( 3 He) = 45 MeV have been measured. The transferred angular momentum in the reaction is deduced from the side-feeding γ-intensities of the ground bands in the residual 162-x Dy isotopes. With decreasing α-energy the average spin transfer increases from similar 5h to similar 11h. The ( 3 He,α) reaction at these energies is dominated by direct processes. Even at the highest spin transfer the contribution from the compound reaction channel is negligible. ((orig.))

Internal Magnus effects in superfluid 3He-A

International Nuclear Information System (INIS)

Salmelin, R.H.; Salomaa, M.M.; Mineev, V.P.

1989-01-01

Orbital angular momentum of the coherently aligned Cooper pairs in superfluid 3 He-A is encountered by an object immersed in the condensate. We evaluate the associated quasiparticle-scattering asymmetry experienced by a negative ion; this leads to a measureable, purely quantum-mechanical reactive force deflecting the ion's trajectory. Possible hydrodynamic Magnus effects are also discussed

Measurement of the Neutron (³He) Spin Structure at Low Q² and the Extended Gerasimov-Drell-Hearn Sum Rule

Energy Technology Data Exchange (ETDEWEB)

Kominis, Ioannis [Princeton Univ., NJ (United States)

2001-01-01

This thesis presents the results of E-94010, an experiment at Thomas Jefferson National Accelerator Facility (TJNAF) designed to study the spin structure of the neutron at low momentum transfer, and to test the “extended” Gerasimov-Drell-Hearn (GDH) sum rule. The first experiment of its kind, it was performed in experimental Hall-A of TJNAF using a new polarized ³He facility. It has recently been shown that the GDH sum rule and the Bjorken sum rule are both special examples of a more general sum rule that applies to polarized electron scattering off nucleons. This generalized sum rule, due to Ji and Osborne, reduces to the GDH sum rule at Q² = 0 and to the Bjorken sum rule at Q² >> 1 GeV². By studying the Q² evolution of the extended GDH sum, one learns about the transition from quark-like behavior to hadronic-like behavior. We measured inclusive polarized cross sections by scattering high energy polarized electrons off the new TJNAF polarized ³He target with both longitudinal and transverse target orientations. The high density ³He target, based on optical pumping and spin exchange, was used as an effective neutron target. The target maintained a polarization of about 35% at beam currents as high as 151tA. We describe the precision ³He polarimetry leading to a systematic uncertainty of the target polarization of 4% (relative). A strained GaAs photocathode was utilized in the polarized electron gun, which provided an electron beam with a polarization of about 70%, known to 3% (relative). By using six different beam energies (between 0.86 and 5.06 GeV) and a fixed scattering angle of 15.5°, a wide kinematic coverage was achieved, with 0.02 GeV²< Q² <1 GcV² and 0.5 GeV< W < 2.5 GeV for the squared momentum transfer and invariant mass, respectively. From the measured cross sections we extract the ³He spin structure functions g$3 He

Experimental Study of Photon Induced Reactions on 3He and 4He at Low Energies

International Nuclear Information System (INIS)

Tornow, W.

2011-01-01

Data are reported for the photodisintegration cross section of the reaction 3 He(γ, p) 2 H at ten energies between 7.0 and 16.0 MeV. Very preliminary data are presented for the reaction 4 He(γ, p) 3 H between 22.0 and 29.5 MeV in 0.5 MeV energy steps, and for the reaction 4 He(γ, n) 3 He at three energies around 28.0 MeV. High-pressure He/Xe gas scintillators served as target and detector. Our data are in better agreement with recent theoretical calculations than the majority of the existing data for all three reactions, but differ significantly from recent data taken with a mono-energetic photon beam and a time-projection chamber. (author)

Autoionization spectra of He excited by fast (MeV) H/sup +/, He/sup +/, and Li/sup n+/ (n = 1,2,3) ions

Energy Technology Data Exchange (ETDEWEB)

Schneider, D.; Arcuni, P.; Bruch, P.; Stoeffler, W.

1983-01-01

Autoionization spectra of He following excitation by 1 to 3 MeV H/sup +/, He/sup +/, and Li/sup n+/ (n = 1,2,3) have been measured as a function of observation angle. The (2p/sup 2/)/sup 1/D and (2s2p)/sup 1/P resonances have been examined and a strong dependence on projectile velocities, charge state and observation angle was found.

Neutron polarization in polarized 3He targets

International Nuclear Information System (INIS)

Friar, J.L.; Gibson, B.F.; Payne, G.L.; Bernstein, A.M.; Chupp, T.E.

1990-01-01

Simple formulas for the neutron and proton polarizations in polarized 3 He targets are derived assuming (1) quasielastic final states; (2) no final-state interactions; (3) no meson-exchange currents; (4) large momentum transfers; (5) factorizability of 3 He SU(4) response-function components. Numerical results from a wide variety of bound-state solutions of the Faddeev equations are presented. It is found that this simple model predicts the polarization of neutrons in a fully polarized 3 He target to be 87%, while protons should have a slight residual polarization of -2.7%. Numerical studies show that this model works very well for quasielastic electron scattering

Photodetachment of metastable He-

International Nuclear Information System (INIS)

Thompson, J.S.; Dellwo, J.; Compton, R.N.

1990-01-01

A crossed-beams apparatus has been used to measure angular distributions and cross sections for photoelectron detachment from metastable He - . Energy- and angle-resolved electron spectroscopy was used to investigate the spectral dependences of the angular distribution of the photoelectrons. The angular distributions along with photoelectron yield measurements were used to determine the cross sections for photodetachment of He - (2 4 P) via the energy resolved He(2 3 P) and He(2 3 S) exit channels. The precision of the cross section measurements was enhanced by exploiting the kinematic effects associated with detachment from a fast beam source. Calculated cross sections for the photodetachment of H - were used to establish an absolute scale for the He - cross section measurements

The (3He,t) and (d,2He)reactions at intermediate energies

International Nuclear Information System (INIS)

Brockstedt, A.

1987-09-01

The ( 3 He,t) reaction has been studied at 0.6-2.3 GeV at small scattering angles, 0-7 degrees, on various nuclei ( 12 C, 13 C, 26 Mg, 40 Ca, 48 Ca, 54 Fe, 90 Zr, 159 Tb, 208 Pb) including a proton target. The reaction is a single-step reaction and selects the spin-isospin channel. Angular distributions for low-lying states in 12 N are well described by DWIA calculations. From 13 C to 13 N transitions the ratio J στ /J τ , at momentum transfer, q, close to zero, is derived. The ratio remains roughly constant in the region 300 - 700 MeV/nucleon. The position of the quasi-free peak is shifted compared with free nucleon-nucleon scattering. The shift is towards higher excitation energies at q approx 1.4 fm -1 , and towards lower excitation energies at q approx 2.5 fm -1 . The p( 3 He,t)Δ ++ reaction is analysed as one-pion exchange and the ( 3 He,t) form factor is extracted. The shape and position of the Δ resonance seem to be independent of target mass for the targets studied. Compared with the p to Δ ++ transition the position is shifted towards lower excitation energy in nuclei. The (d,2p[ 1 S 0 ]) reaction, with the two protons in an 1 S 0 state labelled 2 He, is studied at 0.65 and 2.0 GeV at small angles, 0-4 degrees, on some of the targets used in the ( 3 He,t) experiment (p, 12 C, 40 Ca, 54 Fe). This reaction is also a one-step reaction that can be used for studies of spin-isospin excitations. Cross sections and tensor analysing powers are determined for the p(d, 2 He)n reaction. These results are compared with PWIA calculations. The Δ resonance in carbon is also here shifted down in excitation energy compared with the proton target. (author)

A miniature adsorption3HE refrigerator

International Nuclear Information System (INIS)

Duband, L.; Ravex, A.; Lange, A.

1991-01-01

A self-contained, recyclable laboratory 3 He refrigerator has been developed. The refrigerator is very compact, portable and is designed to be safe and reliable. The unit can easily be installed on the cold plate of a superfluid 4 He cryostat. Once bolted on the cold plate, operation of the refrigerator is controlled by a single heater. In this new design the refrigerator has a cylindrical geometry. The adsorption pump is placed above the condensation point to prevent convection during the condensation phase and to improve the pumping speed. The inhibition of convection reduces the load on the 4 He bath and increases the condensation efficiency. This refrigeration technique has great potential for space applications. The absence of moving parts makes the system reliable and vibration free. Its simplicity and the absence of external components facilitate its integration on a cryostat. In fact, a rocket-borne 3 He refrigerator has already been successfully flown and has demonstrated the feasibility of this method

First doubly polarised photoproduction on {sup 3}He at the photon beam of MAMI

Energy Technology Data Exchange (ETDEWEB)

Aguar Bartolome, Patricia

2010-11-15

A first experiment with a polarised {sup 3}He target was carried out in July 2009 at the MAMI accelerator in Mainz in a photon energy range between 200 MeV and 800 MeV. The aim of this measurement was to investigate the Gerasimov-Drell-Hearn sum rule on the neutron. The use of the data obtained with the polarised {sup 3}He target, compared to existing data on the deuteron, gives a complementary and more direct access to the neutron, due to the spin structure of the {sup 3}He. The measurement of the helicity dependence of the inclusive total photoabsorption cross section required a beam of tagged circularly polarised photons incident on the longitudinally polarised {sup 3}He target. The data were taken using the 4{pi} Crystal Ball photon spectrometer in combination with TAPS as a forward wall and complemented by a threshold Cherenkov detector used to on-line suppress the background from electromagnetic events. The development and preparation of the different components of the {sup 3}He experimental setup was an important part of this work and are described in detail in this thesis. The detector system and the analysis method were tested by the measurement of the unpolarised total inclusive photoabsorption cross section on liquid hydrogen. The results obtained are in good agreement with previous published data. Preliminary results of the unpolarised total photoabsorption cross section, as well as the helicity dependent photoabsorption cross section difference on {sup 3}He compared with several theoretical models will also be presented. (orig.)

The rotational predissociation of HeH+ energy and lifetime measurements, ch. 3

International Nuclear Information System (INIS)

Locht, R.; Maas, J.G.; Asselt, N.P.F.B. van; Los, J.

1976-01-01

Relative lifetimes and energies above the dissociation limit have been determined for the rotational predissociation of several quasi-bound levels of the X'Σ + state of 4 HeH + . In particular, the lifetimes are very sensitive to the shape of the potential energy curve. These measurements are used to discriminate between two ab initio potential curves which differ by only 0.00004 a.u. (approximately 1 meV). Using the lifetime data, relative population factors were determined for the observed levels

A parallel direct solver for the self-adaptive hp Finite Element Method

KAUST Repository

Paszyński, Maciej R.

2010-03-01

In this paper we present a new parallel multi-frontal direct solver, dedicated for the hp Finite Element Method (hp-FEM). The self-adaptive hp-FEM generates in a fully automatic mode, a sequence of hp-meshes delivering exponential convergence of the error with respect to the number of degrees of freedom (d.o.f.) as well as the CPU time, by performing a sequence of hp refinements starting from an arbitrary initial mesh. The solver constructs an initial elimination tree for an arbitrary initial mesh, and expands the elimination tree each time the mesh is refined. This allows us to keep track of the order of elimination for the solver. The solver also minimizes the memory usage, by de-allocating partial LU factorizations computed during the elimination stage of the solver, and recomputes them for the backward substitution stage, by utilizing only about 10% of the computational time necessary for the original computations. The solver has been tested on 3D Direct Current (DC) borehole resistivity measurement simulations problems. We measure the execution time and memory usage of the solver over a large regular mesh with 1.5 million degrees of freedom as well as on the highly non-regular mesh, generated by the self-adaptive h p-FEM, with finite elements of various sizes and polynomial orders of approximation varying from p = 1 to p = 9. From the presented experiments it follows that the parallel solver scales well up to the maximum number of utilized processors. The limit for the solver scalability is the maximum sequential part of the algorithm: the computations of the partial LU factorizations over the longest path, coming from the root of the elimination tree down to the deepest leaf. © 2009 Elsevier Inc. All rights reserved.

Epigenetic regulation of facultative heterochromatinisation in Planococcus citri via the Me(3)K9H3-HP1-Me(3)K20H4 pathway.

Science.gov (United States)

Bongiorni, Silvia; Pasqualini, Barbara; Taranta, Monia; Singh, Prim B; Prantera, Giorgio

2007-03-15

Using RNA interference (RNAi) we have conducted a functional analysis of the HP1-like chromobox gene pchet2 during embryogenesis of the mealybug Planococcus citri. Knocking down pchet2 expression results in decondensation of the male-specific chromocenter that normally arises from the developmentally-regulated facultative heterochromatinisation of the paternal chromosome complement. Together with the disappearance of the chromocenter the staining levels of two associated histone modifications, tri-methylated lysine 9 of histone H3 [Me(3)K9H3] and tri-methylated lysine 20 of histone H4 [Me(3)K20H4], are reduced to undetectable levels. Embryos treated with double-stranded RNA (dsRNA) targeting pchet2 also exhibit chromosome abnormalities, such as aberrant chromosome condensation, and also the presence of metaphases that contain 'lagging' chromosomes. We conclude that PCHET2 regulates chromosome behavior during metaphase and is a crucial component of a Me(3)K9H3-HP1-Me(3)K20H4 pathway involved in the facultative heterochromatinisation of the (imprinted) paternal chromosome set.

Effects of {Delta}-isobar degrees of freedom on the reactions {sup 3}He(n,{gamma}){sup 4}He and {sup 3}He(p,e{sup +}{nu}{sub e}){sup 4}He at low-energy

Energy Technology Data Exchange (ETDEWEB)

Schiavilla, R.

1991-12-31

The cross sections of the radiative {sup 3}He(n,{gamma}){sup 4}He and weak {sup 3}He(p,e{sup +}{nu}{sub e}){sup 4}He capture reactions at thermal neutron and keV proton energies have been calculated with the Variational Monte Carlo method. The ground state and low-energy continuum wave functions have been determined variationally from a realistic Hamiltonian, and include both nucleon and {Delta}-isobar degrees of freedom. The electroweak transition operator contains one- and two-body components in the N + {Delta} Hilbert space.

Effects of. Delta. -isobar degrees of freedom on the reactions sup 3 He(n,. gamma. ) sup 4 He and sup 3 He(p,e sup +. nu. sub e ) sup 4 He at low-energy

Energy Technology Data Exchange (ETDEWEB)

Schiavilla, R.

1991-01-01

The cross sections of the radiative {sup 3}He(n,{gamma}){sup 4}He and weak {sup 3}He(p,e{sup +}{nu}{sub e}){sup 4}He capture reactions at thermal neutron and keV proton energies have been calculated with the Variational Monte Carlo method. The ground state and low-energy continuum wave functions have been determined variationally from a realistic Hamiltonian, and include both nucleon and {Delta}-isobar degrees of freedom. The electroweak transition operator contains one- and two-body components in the N + {Delta} Hilbert space.

Geometrical aspects of reaction cross sections for 3He, 4He and 12C projectiles

International Nuclear Information System (INIS)

Ingemarsson, A.; Lantz, M.

2003-04-01

A black-disc model combined with accurate matter densities has been used for an investigation of reaction cross sections for 3 He, 4 He and 12 C projectiles. A simple relation is derived between the energy dependence of the reaction cross sections and the strength of the nucleon-nucleon interaction. A comparison is also made of the reaction cross sections for 3 He and 4 He for six different nuclei 12 C, 16 O, 40 Ca, 58,60 Ni and 208 Pb

3He impurity states on liquid 4He: From thin films to the bulk surface

International Nuclear Information System (INIS)

Pavloff, N.; Treiner, J.

1991-01-01

The structure of the states accessible to 3 He impurities in films of liquid 4 He on Nuclepore is investigated using a density functional approach with a finite-range effective interaction. In thick films, one finds that the two lowest states are localized in the surface region. For thinner films, the variation with film thickness of the first three states results from a delicate balance between the attractive tail of the substrate potential and the quantum finite-size effect. The existence of states localized in the second layer of the films is discussed. The energy difference between the ground state and the first excited state agrees with the recent determination of Higley, Sprague, and Hallock from magnetization measurements. The effective mass of the ground state has a structure similar to that obtained by Krotscheck and coworkers and exhibits a maximum for a 4 He coverage of 0.15 angstrom -2 , in agreement with the data of Gasparini and coworkers. A similar behavior is predicted for the effective mass of the first, second, and third excited states. The structure of the energy spectrum may also explain former results on third-sound measurements in thin mixture films by Laheurte et al. and by Hallock

Experimental Research of the Radiative Capture of Thermal Neutrons in $^{3}$He

CERN Document Server

Bystritsky, V M; Enik, T L; Filipowicz, M; Gerasimov, V V; Grebenyuk, V M; Kobzev, A P; Kublikov, R V; Nesvizhevsky, V V; Parzhitskii, S S; Pavlov, V N; Popov, N P; Salamatin, A V; Shvetsov, V N; Slepnev, V M; Strelkov, A V; Wozniak, J; Zamyatin, N I

2006-01-01

A project of an experiment on measurement of the cross sections of radiative thermal neutron capture by $^{3}$He nuclei with production of one and two $\\gamma $-quanta ($n_{\\rm th}+^{3}$He $\\to \\alpha + \\gamma $(2$\\gamma $)) is presented. The interest in studying the processes is dictated by the following factors: a possibility of obtaining information on parameters of the nucleon $N$-$N$ potential and structure of exchange meson currents; a possibility of verifying the model of the mechanism for nucleon capture by the nucleus $^{3}$He in the low-energy region; necessity to solve some questions existing in astrophysics. The experiment is planned to be carried out on the PF1B beam of ILL reactor (Grenoble). The target is a hollow cylinder of pure aluminium ($\\varnothing$140$\\times $80~mm) filled with $^{3}$He and $^{4}$He (background experiment) at the pressure 2~atm. Registration of the $\\gamma $-quanta is carried out by four BGO crystal ($\\varnothing$100$\\times $70~mm) detectors. According to the calculation...

Experimental apparatus with {sup 3}He detectors for photoneutron measurements greater than 8 MV; Aparato experimental de detector {sup 3}He, para medida fotonêutrons em acelerador com energia acima 8 MV

Energy Technology Data Exchange (ETDEWEB)

Silva, Marcelo Vilela da; Fontes, Gladson Silva; Cardoso, Domingos D’Oliveira, E-mail: marcelovilelasilva@gmail.com [Instituto Militar de Engenharia (IME), Rio de Janeiro, RJ (Brazil)

2017-07-01

Particle technology has a profound impact on society. Its applications are well established mainly in the treatment of cancer and other diseases. The objective of this work was to develop an experimental apparatus with {sup 3}He detectors for photoneutron measurements greater than 8 MV. The apparatus allowed to obtain a multi energetic neutron measurements with detector and changing the different thicknesses of shields and for different dose rates. Additionally, an analytical model was developed, based on the approximation of the diffusion, for two groups of energy. The results indicated an increasing and linear behavior in the detector response. (author)

186Os and 187Os enrichments and high-3He/4He sources in the Earth's mantle

DEFF Research Database (Denmark)

Brandon, A.D.; Graham, D.W.; Waight, Tod Earle

2007-01-01

at present remains core-mantle interaction. While some plumes with high 3He/4He, such as Hawaii, appear to have been subjected to detectable addition of Os (and possibly He) from the outer core, others such as Iceland do not. A positive correlation between 187Os/188Os and 3He/4He from 9.6 to 19 Ra in Iceland...

Direct harvesting of Helium-3 (3He) from heavy water nuclear reactors

International Nuclear Information System (INIS)

Bentoumi, G.; Didsbury, R.; Jonkmans, G.; Rodrigo, L.; Sur, B.

2013-01-01

The thermal neutron activation of deuterium inside a heavy-water-moderated or -cooled nuclear reactor produces a build-up of tritium in the heavy water. The in situ decay of tritium can, for certain reactor types and operating conditions, produce potentially useable amounts of 3 He, which can be directly extracted via the heavy-water cover gas without first separating, collecting and storing tritium outside the reactor. It is estimated that the amount of 3 He available for recovery from the moderator cover gas of a 700 MWe class Pressurized Heavy Water Reactor (PHWR) ranges from 0.1 to 0.7 m 3 (STP) per annum, varying with the tritium activity buildup in the moderator. The harvesting of 3 He would generate approximately 12.7 m 3 (STP) of 3 He, worth more than $30M at current market rates, over a typical 25-year operating cycle of the PHWR. This paper discusses the production of 3 He in the moderator of a PHWR and its extraction from the 4 He moderator cover gas system using conventional methods. (author)

Spin-exchange and spin-destruction rates for the 3He-Na system

International Nuclear Information System (INIS)

Borel, P.I.; Soegaard, L.V.; Svendsen, W.E.; Andersen, N.

2003-01-01

Optically pumped Na is used as a spin-exchange partner to polarize 3 He. Polarizations around 20% have routinely been achieved in sealed spherical glass cells containing 3 He, N 2 , and a few droplets of Na. An optical technique has been developed to determine the Na- 3 He spin-exchange rate coefficient. By monitoring the Na spin relaxation ''in the dark,'' the average Na-Na spin-destruction cross section at 330 degree sign C is estimated to be around 5x10 -19 cm 2 . This value is 2-5 (15-30) times smaller than the previously reported values for the K-K (Rb-Rb) spin-relaxation cross section. In the temperature range 310-355 degree sign C the spin-exchange rate coefficient is found to be (6.1±0.6)x10 -20 cm 3 /s with no detectable temperature dependence. This value is in good agreement with a previous theoretical estimate reported by Walker and it is only slightly lower than the corresponding Rb- 3 He spin-exchange rate coefficient. The total Na- 3 He spin-destruction rate coefficient is, within errors, found to be the same as the Na- 3 He spin-exchange rate coefficient, thereby indicating that the maximum possible photon efficiency may approach unity for the Na- 3 He system. A technique, in which a charge-coupled device camera is used to take images of faint unquenched fluorescence light, has been utilized to allow for an instantaneous determination of the sodium number densities during the rate coefficient measurements

HP-SEE User Forum 2012

CERN Document Server

Karaivanova, Aneta; Oulas, Anastasis; Liabotis, Ioannis; Stojiljkovic, Danica; Prnjat, Ognjen

2014-01-01

This book is a collection of carefully reviewed papers presented during the HP-SEE User Forum, the meeting of the High-Performance Computing Infrastructure for South East Europe’s (HP-SEE) Research Communities, held in October 17-19, 2012, in Belgrade, Serbia. HP-SEE aims at supporting and integrating regional HPC infrastructures; implementing solutions for HPC in the region; and making HPC resources available to research communities in SEE, region, which are working in a number of scientific fields with specific needs for massively parallel execution on powerful computing resources. HP-SEE brings together research communities and HPC operators from 14 different countries and enables them to share HPC facilities, software, tools, data and research results, thus fostering collaboration and strengthening the regional and national human network; the project specifically supports research groups in the areas of computational physics, computational chemistry and the life sciences. The contributions presented i...

3He release characteristics of metal tritides and scandium--tritium solid solutions

International Nuclear Information System (INIS)

Perkins, W.G.; Kass, W.J.; Beavis, L.C.

1975-01-01

Tritides of such metals as scandium, titanium, and erbium are useful materials for determining the effects of helium accumulation in metallic solids, for example, CTR first wall materials. Such effects include lattice strain and gross deformation, as reported elsewhere, which are related to 3 He retention and ultimate release. Long term gas release studies have indicated that, during the early life of a metal ditritide, a large fraction of the 3 He is retained in the solid. At more advanced ages (2 to 4 years, depending on the parent metal), the 3 He release rate becomes comparable to the generation rate. Statistical analysis of the data indicates that the acceleration in 3 He release rate depends on accumulated 3 He concentration rather than strictly on age. 3 He outgassing results are presented for thin films of ScT 2 , TiT 2 , and ErT 2 , and the critical 3 He concentrations are discussed in terms of a percolation model. Phase transformations which occur on tritide formation cast some doubt on the validity of extrapolating results obtained for metal tritides to predictions regarding the accumulation of helium in metals. Scandium is unique among the early transition and rare-earth metals in that the metal exhibits a very high room temperature tritium solubility (T/Sc = 0.4) with no phase transformation. Indeed, even the lattice parameters of the hcp scandium lattice are only minimally changed by tritium solution, and we have succeeded in obtaining single crystal ScT 0 . 3 samples in two crystallographic orientations. Using a very sensitive technique, we have measured 3 He emission from both these samples, as well as from fine-grained thin film scandium-tritium solid solution samples (ScT 0 . 3 - 0 . 4 ). The fine-grained film samples release 3 He at 2 to 3 percent of the generation rate, while the emission rate from the single-crystal samples is approximately 0.05 percent of the generation rate, indicating a strong grain size effect

Low-energy behavior of the 3He(α,γ)7Be cross section

International Nuclear Information System (INIS)

Osborne, J.L.; Barnes, C.A.; Kavanagh, R.W.; Kremer, R.M.; Mathews, G.J.; Zyskind, J.L.; Parker, P.D.; California Inst. of Tech., Pasadena; Howard, A.J.; California Inst. of Tech., Pasadena

1984-01-01

Cross sections for the 3 He(α,γ) 7 Be reaction have been measured at several energies from Esub(c.m.)=165 to 1169 keV by counting prompt γ-rays from a windowless, differentially pumped, recirculating, 3 He gas target. The cross-section factor S 34 (Esub(c.m.)) and branching ratio γ 1 /γ 0 were determined at each energy. Cross sections were also measured at Esub(c.m.)=947 and 1255 keV by counting the γ-rays from the 7 Be produced in a 3 He gas cell with a Ni entrance foil. Combining the results of these two independent experiments yields a zero-energy intercept for the cross-section factor of S 34 (O) = 0.53+-0.03 keV x b. The relationship between these measurements and serveral theoretical calculations, and the import of the extrapolated cross section for the solar-neutrino problem are discussed. (orig.)

Low-temperature H2-4He and H2-3He targets for operation on an electron beam

International Nuclear Information System (INIS)

Gol'dshtejn, V.A.; Lubyanyj, V.V.

1981-01-01

Structures and basic characteristics of H 2 - 4 He and H 2 - 3 He low temperature targets are given. Technique of 3 He target filling is described. Initial target cooling up to liquid 4 He temperature and its filling up take near approximately 1 h, at that 4 He flow rate equals 15 l. Repeated filling up of 4 He takes 20 min, and target filling up with 3 He - 10-15 min. Good thermal insulation of a cryostat and targets permits the 4 He target to be operated with an electron beam of a mean current of up to 0.5 μA without filling up 4 He for 70 h. At that flow rate of liquid 4 He amounts to 0.2 l/h, and liquid hydrogen - 0.04 l/h. It is concluded that H 2 - 4 He and H 2 - 3 He targets are reliable and simple in operation and permit to work with accelerated particle beams of intensity corresponding to power release >= 0.5 W without corrections for density change [ru

Nuclear spin dynamics in solid {sup 3}He at ultralow temperatures; Kernspindynamik in festem {sup 3}He bei ultratiefen Temperaturen

Energy Technology Data Exchange (ETDEWEB)

Kath, Matthias

2009-11-06

In this thesis the experimental study of the spin dynamics of solid {sup 3}He is described. By means of magnetization measurements above 3 mK a Curie-Weiss behaviour was found with {theta}{sub W}{approx}2.1 mK and by this an order parameter of J={theta}{sub W}k{sub B}/{approx}-0.5 Kk{sub B} was observed, while in the range of 1 to 3 mK a pure Curie behaviour was found. By means of NMR measurements the values of {tau}{sub 1}(6 mK)=240 ms{+-}12 ms and {tau}{sub 1}(1 mK){approx} 40 ms were determined, while spin-echo measurements yielded the spin-spin relaxation time {tau}{sub 2}(6 mK)=4540 {mu}s{+-}140 {mu}s. Furthermore neutron scattering studies were performed. (HSI)

Evaluation of HP0605 and HP0971 genes of efflux pumps in Helicobacter pylori resistance to Metronidazole

Directory of Open Access Journals (Sweden)

Mohammad hasan Shirazi

2009-12-01

Full Text Available Background: The presence of antibiotic resistance has been reported in H.pylori and it is a major cause of treatment failure. Five families of multidrug efflux pumps are defined in bacteria and resistance-nodulation-division (RND pumps are found mainly in gram negative bacteria. TolC is one of RND pump components and play a critical role in drug resistance. It hasn’t been established that RND family has a role in drug resistance in H.pylori. In this study, we assessed the role of two efflux genes in resistant to metronidazole in H.pylori by evaluation of overexpression TolC genes by RT-PCR method. Methods: In five metronidazole resistant strains of H.pylori, total RNA was extracted. RNA treated with DNase and RNA reverse transcribed to cDNA. Aliquots of the cDNA solution were assayed by RT- PCR for HP0605 and HP0971 genes. The levels of mRNA expression were evaluated by densitometry analysis. Results: All five strains displayed overexpression for HP0605 basis of increased concentration of metronidazole. Three strains showed transcripts for HP0971. One of these had transcripts for HP0971 only in Metronidazole concentration equaled to 16 µg/ml but two strains overexpressed adapt to increase concentration of metronidazole. Conclusion: According to current study, HP0605 and HP0971 genes overexpressed due to increase metronidazole. So, increasing of Metronidazole affects in H.pylori΄s efflux system in transcription level.

Quasielastic 3Hp and 3Hep scattering at intermediate energies and Glauber sum rules

International Nuclear Information System (INIS)

Blinov, A.V.; Vanyushin, I.A.; Grechko, V.E.

1984-01-01

Differential cross sections and average energy losses of fast protons in reactions p +3 H→psub(F)+X and p+ 3 He → psub(F)+X are studied making use of the ITEP liquid hydrogen bubble chamber of 80-cm diameter exposed to 2.5-GeV/c tritium nuclei (the kinetic energy of the incident protons in the nucleus rest frame Tsub(p)=0.318 GeV) and to 5-GeV/c 3 He nuclei (Tsub(p)=0.978 GeV). The experimental results are compared to predictions based on the sum rules for differential cross sections and average energy losses in the Glauber-Sitenko multiple scattering theory using the completeness condition for the wave functions of the nuclear excited states and the locality of the nuclear potential. The theory and the data are in good agreement at momentum of 2.5 GeV/c. Inconsistence between the Glauber sum rule predictions and the 5 GeV/c data is attributed to the Δ-isobar production in the intermediate state. It is found that possible six-quark bag admixture in the 3 H and 3 He nuclei does not exceed 5%

Energy dependence and temporal evolution of the 3He/4He ratios in heavy-ion-rich energetic particle events

International Nuclear Information System (INIS)

Moebius, E.; Hovestadt, D.; Klecker, B.; Gloeckler, G.

1980-01-01

The energy dependence of the 3 He/ 4 He ratio between 0.44 and 4.1 MeV per nucleon has been studied for six heavy-ion--rich events observed in 1974 and 1976 using the low-energy dE/dx versus E Ultralow-Energy Particle telescope (ULET) on IMP 8. We find that all selected heavy-ion--rich events are also enriched in 3 He, that the 3 He/ 4 He He ratio decreases with decreasing energies, and that a rapid temporal evolution of the 3 He/ 4 He and the Fe/(H+He) ratios is strongly correlated during one event with the maximum value at the onset. These results are discussed in terms of a model which is based on preferential injection of 3 He and Fe resulting from turbulent ion heating and subsequent Fermi acceleration

The production of He-3 and heavy ion enrichment in He-3-rich flares by electromagnetic hydrogen cyclotron waves

Science.gov (United States)

Temerin, M.; Roth, I.

1992-01-01

A new model is presented for the production of He-3 and heavy ion enrichments in He-3-rich flares using a direct single-stage mechanism. In analogy with the production of electromagnetic hydrogen cyclotron waves in earth's aurora by electron beams, it is suggested that such waves should exist in the electron acceleration region of impulsive solar flares. Both analytic and test-particle models of the effect of such waves in a nonuniform magnetic field show that these waves can selectively accelerate He-3 and heavy ions to MeV energies in a single-stage process, in contrast to other models which require a two-stage mechanism.

Bulk damping of sound in superfluid 3He--4He under stagnation of the normal component

International Nuclear Information System (INIS)

Karchava, T.A.; Sanikidze, D.G.; Chkhaidze, N.D.

1983-01-01

The propagation of waves in superfluid 3 He-- 4 He solutions is considered under partial stagnation of the normal component. The wave processes in capillaries are presented as a superposition of the first sound, second sound, and viscous and diffusion waves. The damping coefficients are calculated for the modified first sound and for the thermal wave in superfluid 3 He-- 4 He solutions and related to the viscosity, thermal conductivity, diffusion, barodiffusion, and thermodiffusion coefficients

Lagrangian of superfluid 3He

International Nuclear Information System (INIS)

Theodorakis, S.

1988-01-01

This paper presents a phenomenological Lagrangian that fully describes the dynamics of any homogeneous phase of superfluid 3 He, unitary or not, omitting relaxation. This Lagrangian is built by using the concept of a local SO(3) x SO(3) x U(1) symmetry. The spin and angular momentum play the role of gauge fields. We derive the Leggett equations for spin and orbital dynamics from the equations of motion, for both the A and the B phase. This Lagrangian not only enables us to describe both the spin and orbital dynamics of superfluid 3 He in a unified fashion, but can also be used for finding the dynamics in any experimental situation. Furthermore, it can describe the dynamics of the magnitude, as well as of the orientation of the order parameter, and thus it can be used to describe the dynamics of the A-B phase transition

The Cosmic Abundance of 3He: Green Bank Telescope Observations

Science.gov (United States)

Balser, Dana; Bania, Thomas

2018-01-01

The Big Bang theory for the origin of the Universe predicts that during the first ~1,000 seconds significant amounts of the light elements (2H, 3He, 4He, and 7Li) were produced. Many generations of stellar evolution in the Galaxy modifies these primordial abundances. Observations of the 3He+ hyperfine transition in Galactic HII regions reveals a 3He/H abundance ratio that is constant with Galactocentric radius to within the uncertainties, and is consistent with the primordial value as determined from cosmic microwave background experiments (e.g., WMAP). This "3He Plateau" indicates that the net production and destruction of 3He in stars is approximately zero. Recent stellar evolution models that include thermohaline mixing, however, predict that 3He/H abundance ratios should slightly decrease with Galactocentric radius, or in places in the Galaxy with lower star formation rates. Here we discuss sensitive Green Bank Telescope (GBT) observations of 3He+ at 3.46 cm in a subset of our HII region sample. We develop HII region models and derive accurate 3He/H abundance ratios to better constrain these new stellar evolution models.

Measurement of alveolar oxygen partial pressure in the rat lung using Carr-Purcell-Meiboom-Gill spin-spin relaxation times of hyperpolarized 3He and 129Xe at 74 mT.

Science.gov (United States)

Kraayvanger, Ryan J; Bidinosti, Christopher P; Dominguez-Viqueira, William; Parra-Robles, Juan; Fox, Matthew; Lam, Wilfred W; Santyr, Giles E

2010-11-01

Regional measurement of alveolar oxygen partial pressure can be obtained from the relaxation rates of hyperpolarized noble gases, (3) He and (129) Xe, in the lungs. Recently, it has been demonstrated that measurements of alveolar oxygen partial pressure can be obtained using the spin-spin relaxation rate (R(2) ) of (3) He at low magnetic field strengths (oxygen partial pressure measurements based on Carr-Purcell-Meiboom-Gill R(2) values of hyperpolarized (3) He and (129) Xe in vitro and in vivo in the rat lung at low magnetic field strength (74 mT) are presented. In vitro spin-spin relaxivity constants for (3) He and (129) Xe were determined to be (5.2 ± 0.6) × 10(-6) Pa(-1) sec(-1) and (7.3 ± 0.4) × 10(-6) Pa(-1) s(-1) compared with spin-lattice relaxivity constants of (4.0 ± 0.4) × 10(-6) Pa(-1) s(-1) and (4.3 ± 1.3) × 10(-6) Pa(-1) s(-1), respectively. In vivo experimental measurements of alveolar oxygen partial pressure using (3) He in whole rat lung show good agreement (r(2) = 0.973) with predictions based on lung volumes and ventilation parameters. For (129) Xe, multicomponent relaxation was observed with one component exhibiting an increase in R(2) with decreasing alveolar oxygen partial pressure. Copyright © 2010 Wiley-Liss, Inc.

Neutron beam effects on spin-exchange-polarized 3He.

Science.gov (United States)

Sharma, M; Babcock, E; Andersen, K H; Barrón-Palos, L; Becker, M; Boag, S; Chen, W C; Chupp, T E; Danagoulian, A; Gentile, T R; Klein, A; Penttila, S; Petoukhov, A; Soldner, T; Tardiff, E R; Walker, T G; Wilburn, W S

2008-08-22

We have observed depolarization effects when high intensity cold neutron beams are incident on alkali-metal spin-exchange-polarized 3He cells used as neutron spin filters. This was first observed as a reduction of the maximum attainable 3He polarization and was attributed to a decrease of alkali-metal polarization, which led us to directly measure alkali-metal polarization and spin relaxation over a range of neutron fluxes at Los Alamos Neutron Science Center and Institute Laue-Langevin. The data reveal a new alkali-metal spin-relaxation mechanism that approximately scales as sqrt[phi_{n}], where phi_{n} is the neutron capture-flux density incident on the cell. This is consistent with an effect proportional to the concentration of electron-ion pairs but is much larger than expected from earlier work.

Tensile and electrical properties of unirradiated and irradiated Hycon 3HP{trademark} CuNiBe

Energy Technology Data Exchange (ETDEWEB)

Zinkle, S.J.; Eatherly, W.S. [Oak Ridge National Lab., TN (United States)

1996-10-01

The unirradiated tensile properties of two different heats of Hycon 3HP{trademark} CuNiBe (HT Temper) have been measured over the temperature range of 20-500{degrees}C for longitudinal and long transverse orientations. The room temperature electrical conductivity has also been measured for both heats. Both heats exhibited a very good combination of strength and conductivity at room temperature. The strength remained relatively high at all test temperatures, with a yield strength of 420-520 MPa at 500{degrees}C. However, low levels of ductility (<5% uniform elongation) were observed at test temperatures above 200-250{degrees}C, due to flow localization adjacent to grain boundaries. Fission neutron irradiation to a dose of {approximately}0.7 dpa at temperatures between 100 and 240{degrees}C produced a slight increase in strength and a significant decrease in ductility. The measured tensile elongation increased with increasing irradiation temperature, with a uniform elongation of {approximately}3.3% observed at 240{degrees}C. The electrical conductivity decreased slightly following irradiation, due to the presence of defect clusters and Ni, Zn, Co transmutation products. The data indicate that CuNiBe alloys have irradiated tensile and electrical properties comparable or superior to CuCrZr and oxide dispersion strengthened copper at temperatures <250{degrees}C, and may be suitable for certain fusion energy structural applications.

On the 3He anomaly in hot subdwarf B stars

Science.gov (United States)

Schneider, David; Irrgang, Andreas; Heber, Ulrich; Nieva, Maria F.; Przybilla, Norbert

2017-12-01

Decades ago, 3He isotope enrichment in helium-weak B-type main-sequence, in blue horizontal branch and in hot subdwarf B (sdB) stars, i.e., helium-core burning stars of the extreme horizontal branch, were discovered. Diffusion processes in the atmosphere of these stars lead to the observed abundance anomalies. Quantitative spectral analyses of high-resolution spectra to derive photospheric isotopic helium abundance ratios for known 3He sdBs have not been performed yet. We present preliminary results of high-resolution and high S/N spectra to determine the 3He and 4He abundances of nine known 3He sdBs. We used a hybrid local/non-local thermodynamic equilibrium (LTE/NLTE) approach for B-type stars investigating multiple He i lines, including λ4922 Å and λ6678 Å, which show the strongest isotopic shifts in the optical spectral range.We also report the discovery of four new 3He sdBs from the ESO Supernova Progenitor survey. Most of the 3He sdBs cluster in a narrow temperature strip between ˜ 26000 K and ˜ 30000 K and have almost no atmospheric 4He at all. Interestingly, three 3He sdBs show evidence for vertical helium stratification.

On the 3He anomaly in hot subdwarf B stars

Directory of Open Access Journals (Sweden)

Schneider David

2017-12-01

Full Text Available Decades ago, 3He isotope enrichment in helium-weak B-type main-sequence, in blue horizontal branch and in hot subdwarf B (sdB stars, i.e., helium-core burning stars of the extreme horizontal branch, were discovered. Diffusion processes in the atmosphere of these stars lead to the observed abundance anomalies. Quantitative spectral analyses of high-resolution spectra to derive photospheric isotopic helium abundance ratios for known 3He sdBs have not been performed yet. We present preliminary results of high-resolution and high S/N spectra to determine the 3He and 4He abundances of nine known 3He sdBs. We used a hybrid local/non-local thermodynamic equilibrium (LTE/NLTE approach for B-type stars investigating multiple He i lines, including λ4922 Å and λ6678 Å, which show the strongest isotopic shifts in the optical spectral range.We also report the discovery of four new 3He sdBs from the ESO Supernova Progenitor survey. Most of the 3He sdBs cluster in a narrow temperature strip between ∼ 26000 K and ∼ 30000 K and have almost no atmospheric 4He at all. Interestingly, three 3He sdBs show evidence for vertical helium stratification.

3He-MRI in follow-up of lung transplant recipients

International Nuclear Information System (INIS)

Gast, Klaus Kurt; Zaporozhan, Julia; Ley, Sebastian; Biedermann, Alexander; Knitz, Frank; Eberle, Balthasar; Schmiedeskamp, Joerg; Heussel, Claus-Peter; Mayer, Eckhard; Schreiber, Wolfgang Guenter; Thelen, Manfred; Kauczor, Hans-Ulrich

2004-01-01

The aim of this study was to evaluate the possible contribution of 3 He-MRI to detect obliterative bronchiolitis (OB) in the follow-up of lung transplant recipients. Nine single- and double-lung transplanted patients were studied by an initial and a follow-up 3 He-MRI study. Images were evaluated subjectively by estimation of ventilation defect area and quantitatively by individually adapted threshold segmentation and subsequent calculation of ventilated lung volume. Bronchiolitis obliterans syndrome (BOS) was diagnosed using pulmonary function tests. At 3 He-MRI, OB was suspected if ventilated lung volume had decreased by 10% or more at the follow-up MRI study compared with the initial study. General accordance between pulmonary function testing and 3 He-MRI was good, although subjective evaluation of 3 He-MRI underestimated improvement in ventilation as obtained by pulmonary function tests. The 3 He-MRI indicated OB in 6 cases. According to pulmonary function tests, BOS was diagnosed in 5 cases. All diagnoses of BOS were also detected by 3 He-MRI. In 2 of these 5 cases, 3 He-MRI indicated OB earlier than pulmonary function tests. The results support the hypothesis that 3 He-MRI may be sensitive for early detection of OB and emphasize the need for larger prospective follow-up studies. (orig.)

Experimental research of the radiative capture of thermal neutrons in 3He

International Nuclear Information System (INIS)

Bystritskij, V.M.; Enik, T.L.; Gerasimov, V.V.; Grebenyuk, V.M.; Kobzev, A.P.; Kublikov, R.V.; Parzhitskij, S.S.; Pavlov, V.N.; Salamatin, A.V.; Shvetsov, V.N.; Slepnev, V.M.; Strelkov, A.V.; Zamyatin, N.I.; Bystritskij, V.M.; Filipowicz, M.; Nesvizhevskij, V.V.; Popov, N.P.; Wozniak, J.

2006-01-01

A project of an experiment on measurement of the cross sections of radiative thermal neutron capture by 3 He nuclei with production of one and two γ-quanta (n th + 3 He→α+γ(2γ)) is presented. The interest in studying the processes is dictated by the following factors: a possibility of obtaining information on parameters of the nucleon N-N potential and structure of exchange meson currents; a possibility of verifying the model of the mechanism for nucleon capture by the nucleus 3 He in the low-energy region; necessity to solve some questions existing in astrophysics. The experiment is planned to be carried out on the PF1B beam of the ILL reactor (Grenoble). The target is a hollow cylinder of pure aluminium (diam. 140x80 mm) filled with 3 He and 4 He (background experiment) at the pressure 2 atm. Registration of the γ-quanta is carried out by four BGO crystal (diam. 100x70 mm) detectors. According to the calculations the experiment, with 400-500 h of the PF1B beam running time, will allow cross sections for the above reactions to be measured for the first time with an accuracy of 2-4% (one-quantum process) and 7-10 % (two-quantum process), which quite meets the purposes of the project

Ion pair production and chemi-ionisation in collisions of He*(2sup(1,3)S) with Li

International Nuclear Information System (INIS)

Wang, D.P.; Tang, S.Y.; Neynaber, R.H.

1987-01-01

A merging-beams technique has been used to study collisions of He*(2sup(1,3)S) with Li. The He* represents a composite of 13% He(2 1 S) and 87% He(2 3 S). Absolute and relative cross sections, Q, have been measured in a range of relative kinetic energy, W, from 150 to 1500 eV for the ion pair production (IPP) of He + + Li - , and from 0.01 to 500 eV for chemi-ionisation (CI). Information obtained for CI shows that: the Penning ionisation reaction is directed with most of the Li + scattered in the incident Li direction, the He*-Li system is attractive with a measured well depth of 0.73 eV and the value of Q for total ionisation varies as Wsup(-0.34). Similarities to the He*-He* system are also given. (author)

Neutron multiplicity measurements with ³He alternative: Straw neutron detectors

Energy Technology Data Exchange (ETDEWEB)

Mukhopadhyay, Sanjoy [Arnold Avenue Andrews AFB, Joint Base Andrews, MD (United States); Wolff, Ronald [Arnold Avenue Andrews AFB, Joint Base Andrews, MD (United States); Detwiler, Ryan [Arnold Avenue Andrews AFB, Joint Base Andrews, MD (United States); Maurer, Richard [Arnold Avenue Andrews AFB, Joint Base Andrews, MD (United States); Mitchell, Stephen [National Security Technologies, LLC, Las Vegas, NV (United States); Guss, Paul [Remote Sensing Lab. - Nellis, Las Vegas, NV (United States); Lacy, Jeffrey L. [Proportional Technologies, Inc., Houston, TX (United States); Sun, Liang [Proportional Technologies, Inc., Houston, TX (United States); Athanasiades, Athanasios [Proportional Technologies, Inc., Houston, TX (United States)

2015-01-27

Counting neutrons emitted by special nuclear material (SNM) and differentiating them from the background neutrons of various origins is the most effective passive means of detecting SNM. Unfortunately, neutron detection, counting, and partitioning in a maritime environment are complex due to the presence of high-multiplicity spallation neutrons (commonly known as ‘‘ship effect ’’) and to the complicated nature of the neutron scattering in that environment. A prototype neutron detector was built using ¹⁰B as the converter in a special form factor called ‘‘straws’’ that would address the above problems by looking into the details of multiplicity distributions of neutrons originating from a fissioning source. This paper describes the straw neutron multiplicity counter (NMC) and assesses the performance with those of a commercially available fission meter. The prototype straw neutron detector provides a large-area, efficient, lightweight, more granular (than fission meter) neutron-responsive detection surface (to facilitate imaging) to enhance the ease of application of fission meters. Presented here are the results of preliminary investigations, modeling, and engineering considerations leading to the construction of this prototype. This design is capable of multiplicity and Feynman variance measurements. This prototype may lead to a near-term solution to the crisis that has arisen from the global scarcity of ³He by offering a viable alternative to fission meters. This paper describes the work performed during a 2-year site-directed research and development (SDRD) project that incorporated straw detectors for neutron multiplicity counting. The NMC is a two-panel detector system. We used ¹⁰B (in the form of enriched boron carbide: ¹⁰B₄C) for neutron detection instead of ³He. In the first year, the project worked with a panel of straw neutron detectors, investigated its characteristics, and

Recent advancements of wide-angle polarization analysis with 3He neutron spin filters

International Nuclear Information System (INIS)

Chen, W.C.; Gentile, T.R.; Ye, Q.; Kirchhoff, A.; Watson, S.M.; Rodriguez-Rivera, J.A.; Qiu, Y.; Broholm, C.

2016-01-01

Wide-angle polarization analysis with polarized 3 He based neutron spin filters (NSFs) has recently been employed on the Multi-Axis Crystal Spectrometer (MACS) at the National Institute of Standards and Technology Center for Neutron Research (NCNR). Over the past several years, the apparatus has undergone many upgrades to address the fundamental requirements for wide angle polarization analysis using spin exchange optical pumping based 3 He NSFs. In this paper, we report substantial improvements in the on-beam-line performance of the apparatus and progress toward routine user capability. We discuss new standard samples used for 3 He NSF characterization and the flipping ratio measurement on MACS. We further discuss the management of stray magnetic fields produced by operation of superconducting magnets on the MACS instrument, which can significantly reduce the 3 He polarization relaxation time. Finally, we present the results of recent development of horseshoe-shaped wide angle cells. (paper)

Inelastic electron scattering from 3He and 4He in the threshold region at high momentum transfer

International Nuclear Information System (INIS)

Rock, S.; Arnold, R.G.; Chertok, B.T.; Szalata, Z.M.; Day, D.; McCarthy, J.S.; Martin, F.; Mecking, B.A.; Sick, I.; Tamas, G.

1981-01-01

The cross section for inclusive inelastic electron scattering from the helium isotopes has been measured at momentum transfers squared of 0.8 less than or equal to Q 2 less than or equal to 5.0 (GeV/c) 2 for 3 He and 0.8 less than or equal to Q 2 less than or equal to 2.4 (GeV/c) 2 for 4 He. The data were taken at 10 0 and cover the range 1.0 2 /2M/sub He/ν, which includes the elastic peak, nuclear breakup threshold, the high momentum tail of the quasi elastic scattering, and pion production. The structure function, νW 2 , derived from the data is approaching a scaling limit at high Q 2 . It can be factored into a product of functions of Q 2 and of x as predicted by some models

³He Alternatives Summary Report

Energy Technology Data Exchange (ETDEWEB)

McElroy, Robert Dennis [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

2015-11-01

Most of the ³He consumed by neutron-based safeguards assay systems is used in neutron coincidence and neutron multiplicity counting systems. Detection methods for the limited number of total neutron counting applications are not considered in this report, but it is believed that the boron-lined tubes [1, 2] already developed for portal monitoring applications will serve as a suitable replacement for those measurements. In this report, we discuss the potential replacement technologies that are most suitable for use in safeguards applications.

/sup 3/He functions in tokamak-pumped laser systems

Energy Technology Data Exchange (ETDEWEB)

Jassby, D.L.

1986-10-01

/sup 3/He placed in an annular cell around a tokamak fusion generator can convert moderated fusion neutrons to energetic ions by the /sup 3/He(n,p)T reaction, and thereby excite gaseous lasants mixed with the /sup 3/He while simultaneously breeding tritium. The total /sup 3/He inventory is about 4 kg for large tokamak devices. Special configurations of toroidal-field magnets, neutron moderators and beryllium reflectors are required to permit nearly uniform neutron current into the laser cell with minimal attenuation. The annular laser radiation can be combined into a single output beam at the top of the tokamak.

The new phases of liquid 3He

International Nuclear Information System (INIS)

Leggett, A.J.

1976-01-01

Comments are made on two new phases of liquid 3 He, referred to as 3 He-A and 3 He-B, discovered in the temperature region below 3 mk. It has been assumed that these new phases are anisotropic superfluids, and a general picture of them is presented, which has been successful in explaining at least qualitatively, many of the static, dynamic and transport properties of the new phases. Whilst the qualitative behaviour is in good agreement with theory there are, however, some quantitative discrepancies. In many cases these may be due to orientational and geometric effects not yet understood. One of the most fruitful areas for comparison of theory and experiment is the NMR behaviour and the dynamic nuclear magnetism. The anomalous behaviour observed arises because the nuclear dipole energy, although very small, can act coherently in the superfluid state. (U.K.)

MeV ion loss during 3He minority heating in TFTR

International Nuclear Information System (INIS)

Zweben, S.J.; Hammett, G.; Boivin, R.; Phillips, C.; Wilson, R.

1992-01-01

The loss of MeV ions during 3 He ICRH minority heating experiments has been measured using scintillator detectors near the wall of TFTR. The observed MeV ion losses to the bottom (90 degrees poloidal) detector are generally consistent with the expected first-orbit loss of D- 3 He alpha particle fusion products, with an inferred global reaction rate up to ∼10 16 reactions/sec. A qualitatively similar but unexpectedly large loss occurs 45 degrees poloidally below the outer midplane. This additional loss might be due to ICRH tail ions or to ICRH wave-induced loss of previously confined fusion products

Gas exchange rates measured using a dual-tracer (SF6 and3he) method in the coastal waters of Korea

Science.gov (United States)

Lee, Hyun-Woo; Lee, Kitack; Kaown, Duk-In

2008-03-01

Over a period of 5 days between August 12 and 17, 2005, we performed a gas exchange experiment using the dual tracer method in a tidal coastal ocean located off the southern coast of Korea. The gas exchange rate was determined from temporal changes in the ratio of3He to SF6 measured daily in the surface mixed layer. The measured gas exchange rate ( k CO 2), normalized to a Schmidt number of 600 for CO2 in fresh water at 20°C, was approximately 5.0 cm h-1 at a mean wind speed of 3.9 m s-1 during the study period. This value is significantly less than those obtained from floating chamber-based experiments performed previously in estuarine environments, but is similar in magnitude to values obtained using the dual tracer method in river and tidal coastal waters and values predicted on the basis of the relationship between the gas exchange rate and wind speed (Wanninkhof 1992), which is generally applicable to the open ocean. Our result is also consistent with the relationship of Raymond and Cole (2001), which was derived from experiments carried out in estuarine environments using222Rn and chlorofluorocarbons along with measurements undertaken in the Hudson River, Canada, using SF6 and3He. Our results indicate that tidal action in a microtidal region did not discernibly enhance the measured k CO 2 value.

Nuclear magnetism of liquid 3He: new determination of the Landau parameter F0a

International Nuclear Information System (INIS)

Goudon, V.

2006-10-01

He 3 is a liquid Fermi model, isotropic, with an attainable Fermi temperature and the interaction between atoms can be controlled by changing the pressure of the liquid. In this document, we present accurate NMR measurements of the nuclear magnetic susceptibility of liquid He 3 as a function of temperature and pressure. The emphasis has been placed on reliable thermometry and on He 3 pressure measurements directly in the cell to increase the measuring range until solidification, and an accurate characterization of the NMR spectrometer. Our measurements give an effective Fermi temperature 5% lower than former results. The Landau parameter F 0 a depends on the effective mass, which is determined by specific heat measurements, and consequently on the temperature scale. The re-analysis of the specific heat measurements with the PLTS-2000 temperature scale yields an effective mass increase of 4.5%. In this document, F 0 a is determined for 2 temperature scales (PLTS-2000 and Greywall). Contrarily to former measurements, the F 0 a density dependence does not show any saturation at high pressures. (author)

Crystal blocking measurements of the induced fission time in the sup 2 sup 3 sup 2 Th+p and sup 2 sup 3 sup 2 Th+ sup 3 He reactions

CERN Document Server

Drozdov, V A; Fotina, O V; Giardina, G; Malaguti, F; Platonov, S Y; Tulinov, A F; Yuminov, O A

2002-01-01

The crystal blocking technique has been used to measure the induced fission lifetimes for the sup 2 sup 3 sup 2 sup , sup 2 sup 3 sup 3 Pa and sup 2 sup 3 sup 2 U nuclei produced in the sup 2 sup 3 sup 2 Th+p and sup 2 sup 3 sup 2 Th+ sup 3 He reactions at bombarding energies of protons and sup 3 He included in the 6.8-7.8 MeV and 20.8-23.4 MeV ranges, respectively. The experimental fission lifetimes observed in these reactions vary from 10 sup - sup 1 sup 6 to 10 sup - sup 1 sup 4 s, depending on the projectile energy. Experimental data have been compared with the statistical model calculations that take into account the existence of both classes of excited states of fissioning nucleus, realized in the first and second potential wells of the double-humped fission barrier. By the analysis of the measured decay times it is possible to determine the absolute values of the level density in the second well, type of shape symmetry in the second well, and also the unknown early values of the shell correction for th...

Analysis of the human HP1 interactome reveals novel binding partners

DEFF Research Database (Denmark)

Rosnoblet, Claire; Vandamme, Julien; Völkel, Pamela

2011-01-01

Heterochromatin protein 1 (HP1) has first been described in Drosophila as an essential component of constitutive heterochromatin required for stable epigenetic gene silencing. Less is known about the three mammalian HP1 isotypes CBX1, CBX3 and CBX5. Here, we applied a tandem affinity purification...

Differential cross section measurement for the 6Li(n,t)4He Reaction

International Nuclear Information System (INIS)

Zhang Guohui; Tang Guoyou; Chen Jinxiang; Shi Zhaomin

2002-01-01

The differential cross sections and integrated cross sections of the 6 Li(n,t) 4 He reaction were measured at 1.85 and 2.67 MeV by using a gridded ionization chamber. Neutrons were produced through the T(p, n) 3 He reaction. The absolute neutron flux was determined through the 238 U(n, f) reaction. Present results are compared with existing data

Thermodynamic study of the A-B phase transition in superfluid 3He: Phase diagram and consequences

International Nuclear Information System (INIS)

Hahn, I.

1993-01-01

The authors have measured the A-B phase transition temperature of superfluid 3 He at pressures from zero to 29 bars, and in all magnetic fields up to the high field limit of the B phase (0.59 Tesla). This work is the first precision measurement of the A-B phase transition over the entire phase diagram (P, T, B). Measurements at low magnetic fields can be related to microscopic interactions in liquid 3 He. The results show that all current microscopic models of normal liquid 3 He are incomplete. Also, the results suggest the possibility that the conventional identification of the order parameter of superfluid 3 He-A is incorrect. The measurements at high magnetic fields can be related through thermodynamic identities to quantities which are immeasurable directly, such as the molar volume changes at the A-B phase transition, and the specific heat of the A-phase of superfluid 3 He in the limit T → 0. The authors detect the phase transition by monitoring the attenuation of zero around traversing a 4-mm path in the superfluid. Because thermometry is so crucial to the success of the measurements, the authors elected to use two independent thermometers. The authors use a pulsed NMR measurement of the susceptibility of Pt nuclei, which varies as 1/T, to guarantee linearity of the temperature scale. In order to achieve the high resolution required by the experiment, the authors also use an LCMN thermometer driven by a unique digital bridge which the authors constructed

Hyperpolarized 3He magnetic resonance imaging: Preliminary evaluation of phenotyping potential in chronic obstructive pulmonary disease

International Nuclear Information System (INIS)

Mathew, Lindsay; Kirby, Miranda; Etemad-Rezai, Roya; Wheatley, Andrew; McCormack, David G.; Parraga, Grace

2011-01-01

Rationale and objectives: Emphysema and small airway obstruction are the pathological hallmarks of chronic obstructive pulmonary disease (COPD). The aim of this pilot study in a small group of chronic obstructive pulmonary disease (COPD) patients was to quantify hyperpolarized helium-3 ( 3 He) magnetic resonance imaging (MRI) functional and structural measurements and to explore the potential role for 3 He MRI in detecting the lung structural and functional COPD phenotypes. Materials and methods: We evaluated 20 ex-smokers with stage I (n = 1), stage II (n = 9) and stage III COPD (n = 10). All subjects underwent same-day plethysmography, spirometry, 1 H MRI and hyperpolarized 3 He MRI at 3.0 T. 3 He ventilation defect percent (VDP) was generated from 3 He static ventilation images and 1 H thoracic images and the 3 He apparent diffusion coefficient (ADC) was derived from diffusion-weighted MRI. Results: Based on the relative contribution of normalized ADC and VDP, there was evidence of a predominant 3 He MRI measurement in seven patients (n = 3 mainly ventilation defects or VDP dominant (VD), n = 4 mainly increased ADC or ADC dominant (AD)). Analysis of variance (ANOVA) showed significantly lower ADC for subjects with predominantly elevated VDP (p = 0.02 compared to subjects with predominantly elevated ADC; p = 0.008 compared to mixed group) and significantly decreased VDP for subjects with predominantly elevated ADC (p = 0.003, compared to mixed group). Conclusion: In this small pilot study, a preliminary analysis shows the potential for 3 He MRI to categorize or phenotype COPD ex-smokers, providing good evidence of feasibility for larger prospective studies.

HP investeerib tulevikku / Fredy-Edwin Esse

Index Scriptorium Estoniae

Esse, Fredy-Edwin

2010-01-01

Maailma suurima tehnoloogiafirma Hewlett-Packard (HP) tootearenduskulud kasvasid IV kvartalis 16%, 814 mln dollarini. Autor märgib, et HP aktsia on praegu väga hea saak, kuid mingit imehüpet aktsia hinnas ei tuleks kindlasti oodata

Precise zero-sound velocity measurements in the A and A1 phases of 3He near T/sub c/

International Nuclear Information System (INIS)

Berg, R.F.; Ihas, G.G.

1983-01-01

The authors have made phase-velocity change measurements for 5 and 15 MHz zero sound within a few microkelvin of the 3 He superfluid transition, T/sub c/, at 31.1 bar. The results show no marked feature at homega = 2Δ(T). However, there is a marked reduction in the slope of dc/dT upon passing from the A-phase into the Al-phase. 2 references

Heterochromatin marks HP1γ, HP1α and H3K9me3, and DNA damage response activation in human testis development and germ cell tumours

DEFF Research Database (Denmark)

Bartkova, J; Moudry, P; Hodny, Z

2011-01-01

activation in CIS; and enhanced HP1α in teratoma structures with epithelial and neuronal differentiation. Differential expression of the three heterochromatin markers suggests their partly non-overlapping roles, and separation of heterochromatinization from DDR activation highlights distinct responses...

Examination of X-ray spectra from the antiprotonic helium isotopes 3He and 4He

International Nuclear Information System (INIS)

Schneider, M.

1987-05-01

Using the high intensity antiprotonic LEAR beam at CERN (Geneva), several measurements were done to investigate the X-ray spectra of the antiprotonic Helium isotopes 3 He and 4 He. For the first time antiprotons were stopped in gases at low pressures (600, 375, 72 and 36 mbar), which permitted observations on nearly isolated atoms. A newly developed method for stopping the antiprotons in gases by means of a focusing cyclotron field surrounding the target gas was used. The field was supplied by a superconducting magnet ('cyclotron trap'). The antiprotons were tangentially injected into the cyclotron field, where they slowed down by ionising the target gas. The inhomogeneous magnetic field guided the antiprotons in spiral orbits to the magnetic center. Thus, even at low pressures a very small stopping volume could be achieved. To detect the X-rays different Si(Li)- and Ge-semiconductor detectors were used, some of which were furnished with 'guard-rings'. They were used to investigate the effects of the strong interaction between the antiproton and the nucleus in the (3d → 2p) transition in both isotopes. The analyzis of this transition permitted directly the determination of the shift and width of the 2p-level. The width of the 3d-level could be determined only indirectly using an intensity balance. The utilization of gases with different pressures permitted investigations of the pressure dependence of the antiprotonic deexcitation process. The results for the widths and shifts were compared with earlier measurements and theoretical predictions. The theory agrees only partly with the measurements. The evaluation of a complex scattering length using an optical model contradicts some of the results of calculations. (orig.) [de

Specific features of kinetics of He/sup 3/-He/sup 4/ solid solution transformations at superlow temperatures

Energy Technology Data Exchange (ETDEWEB)

Mikheev, V A; Majdanov, V A; Mikhin, N P

1986-06-01

The NMR data on the phase transition kinetics of /sup 3/He-/sup 4/He solid solutions at T=100 mK are considered. Studied are solid helium samples of a molecular volume of 20.55 cm/sup 2//mol with a /sup 3/He content of 0.54%. An unusually long phase transition time is found which is dependent on the prehistory of sample. The spin diffusion of /sup 3/He in the transformated solution concentrated phase is found to be of a quasi-one-dimensional nature with the diffusion coefficient value typical of liquid.

Ab initio study of small He cluster ions Hen+, n=2, 3, 4, 5, and low-lying Rydberg states of He4

International Nuclear Information System (INIS)

Staemmler, V.

1990-01-01

SCF and CEPA calculations are applied to study the structure of small He cluster ions, He n 3 , n=2, 3, 4, 5 and some low-lying Rydberg states of He 4 . The effect of electron correlation upon the equilibrium structures and binding energies is discussed. He 3 + has a linear symmetric equilibrium geometry with a bond length of 2.35 a 0 and a binding energy D e =0.165 eV with respect to He 2 + +He (experimentally: D 0 =0.17 eV which corresponds to D e ≅0.20 eV). He 4 + is a very floppy molecular ion with several energetically very similar geometrical configurations. Our CEPA calculations yield a T-shaped form with a He 3 + centre (R e =2.35 a 0 ) and one inductively bound He atom (4.39 a 0 from the central He atom of He 3 + ) as equilibrium structure. Its binding energy with respect to He 3 + +He is 0.031 eV. A linear symmetric configuration consisting of a He 2 + centre with a bond length of 2.10 a 0 and two inductively bound He atoms (4.20 a 0 from the centre of He 2 + ) is only 0.02-0.03 eV higher in energy. We expect that in larger He cluster ions structures with He 2 + and He 3 + centres and n-2 or n-3 inductively bound He atoms have nearly the same energies. In He 4 a low-lying metastable Rydberg state ( 3 π symmetry for linear He 4 * , 3 B 1 for the T-shaped form) exists which is slightly stronger bound with respect to He 3 * +He than the corresponding ion. (orig.)

3He/4He production ratios by tetrahedral symmetric condensation

International Nuclear Information System (INIS)

Takahashi, Akito

2006-01-01

The present paper treats application of the Electronic Quasi-Particle Expansion Theory (EQPET) model for Tetrahedral Symmetric Condensate (TSC) of H/D mixed systems for Pd host metal. Production ratios of 3 He/ 4 He for multi-body fusion reactions in H/D mixed TSC systems are calculated as a function of H/D mixing ratio. The model is further extended to treat direct nuclear interactions between host-metal nucleus and TSC of pure four protons (or four deuterons), since TSC can become very small (far less than 1 pm radius) charge-neutral pseudo-particle. Results for the case of Ni + 4p/TSC are discussed with Ni + p capture reactions and Ni + 4p fission reactions. (authors)

[Pr2(pdc3(Hpdc(H2O4]n·n(H3hp·8n(H2O, a One-Dimensional Coordination Polymer Containing PrO6N3 Tri-Capped Trigonal Prisms and PrO8N Mono-Capped Square Anti-Prisms (H2pdc = Pyridine 2,6-Dicarboxylic Acid, C7H5NO4; 3hp = 3-Hydroxy Pyridine, C5H5NO

Directory of Open Access Journals (Sweden)

Shahzad Sharif

2012-08-01

Full Text Available The synthesis, structure and some properties of the one-dimensional coordination polymer, [Pr2(pdc3(Hpdc]n·n(H3hp·8n(H2O, (H2pdc = pyridine 2,6-dicarboxylic acid, C7H5NO4; 3hp = 3-hydroxypyridine, C5H5NO are described. One of the Pr3+ ions is coordinated by two O,N,O-tridentate pdc2− ligands and one tridentate Hpdc− anion to generate a fairly regular PrO6N3 tri-capped trigonal prism, with the N atoms acting as the caps. The second Pr3+ ion is coordinated by one tridentate pdc2− dianion, four water molecules and two monodentate bridging pdc2− ligands to result in a PrO8N coordination polyhedron that approximates to a mono-capped square-anti-prism. The ligands bridge the metal-atom nodes into a chain, which extends in the [100] direction. The H3hp+ cation and uncoordinated water molecules occupy the inter-chain regions and an N–HLO and numerous O–HLO hydrogen bonds consolidate the structure. The H3hp+ species appears to intercalate between pendant pdc rings to consolidate the polymeric structure. Crystal data: 1 (C33H43N5O29Pr2, Mr = 1255.54, triclinic,  (No. 2, Z = 2, a = 13.2567(1 Å, b = 13.6304(2 Å, c = 13.6409(2 Å, α = 89.695(1°, β = 63.049(1°, γ = 86.105(1°, V = 2191.16(5 Å3, R(F = 0.033, wR(F2 = 0.084.

Direct liquid content measurement applicable for He II space cryostats

International Nuclear Information System (INIS)

Wanner, M.

1988-01-01

A direct calorimetric method for content measurement in the He II cryostat ISO was assessed. A well defined heat pulse into the He II bath causes a small temperature increase which can be measured and directly correlated to the liquid mass through the He II specific heat. To study this method under the potential zero gravity constraints of disconnected liquid volumes a setup was established for investigating heat transfer between separated liquid volumes. The results for different fluid configurations confirm that even for completely disconnected volumes the heat is almost immediately distributed throughout the whole liquid by evaporation and recondensation

6 Ma age of carving Westernmost Grand Canyon: Reconciling geologic data with combined AFT, (U-Th)/He, and 4He/3He thermochronologic data

Science.gov (United States)

Winn, Carmen; Karlstrom, Karl E.; Shuster, David L.; Kelley, Shari; Fox, Matthew

2017-09-01

Conflicting hypotheses about the timing of carving of the Grand Canyon involve either a 70 Ma (;old;) or conflict with these lines of evidence, but are reconciled in this paper via the integration of three methods of analyses on the same sample: apatite (U-Th)/He ages (AHe), 4He/3He thermochronometry (4He/3He), and apatite fission-track ages and lengths (AFT). HeFTy software was used to generate time-temperature (t-T) paths that predict all new and published 4He/3He, AHe, and AFT data to within assumed uncertainties. These t-T paths show cooling from ∼100 °C to 40-60 °C in the Laramide (70-50 Ma), long-term residence at 40-60 °C in the mid-Tertiary (50-10 Ma), and cooling to near-surface temperatures after 10 Ma, and thus support young incision of the westernmost Grand Canyon. A subset of AHe data, when interpreted alone (i.e. without 4He/3He or AFT data), are better predicted by t-T paths that cool to surface temperatures during the Laramide, consistent with an ;old; Grand Canyon. However, the combined AFT, AHe, and 4He/3He analysis of a key sample from Separation Canyon can only be reconciled by a ;young; Canyon. Additional new AFT (5 samples) and AHe data (3 samples) in several locations along the canyon corridor also support a ;young; Canyon. This inconsistency, which mimics the overall controversy of the age of the Grand Canyon, is reconciled here by optimizing cooling paths so they are most consistent with multiple thermochronometers from the same rocks. To do this, we adjusted model parameters and uncertainties to account for uncertainty in the rate of radiation damage annealing in these apatites during sedimentary burial and the resulting variations in He retentivity. In westernmost Grand Canyon, peak burial conditions (temperature and duration) during the Laramide were likely insufficient to fully anneal radiation damage that accumulated during prolonged, near-surface residence since the Proterozoic. We conclude that application of multiple

Production of d, t, 3He, anti d, anti t and anti 3He by 200 GeV protons

International Nuclear Information System (INIS)

Bozzoli, W.; Giacomelli, G.; Rimondi, F.; Zylberajch, S.; Lesquoy, E.; Meunier, R.; Moscoso, L.; Muller, A.; Bussiere, A.

1978-01-01

Data are presented on the yields of d, t, 3 He, anti d, anti t, and anti 3 He with laboratory momenta between 12 and 37 GeV/c produced by 200 GeV protons on beryllium and aluminium. The production yield of nuclei depends significantly on the target nucleus, while the anti d production is independent of target material. The mass dependence of the production cross section is exponential for both nuclei and antinuclei

Coherent photoproduction of π+ on 3He in the (3,3) resonance region

International Nuclear Information System (INIS)

Boyard, J.-L.

1975-01-01

An experimental study of the 3 He(γ,π + ) 3 H reaction has been performed in the (3,3) resonance region with a bremsstrahlung photon beam and a liquid 3 He target. A magnetic spectrometer followed by a wire chamber analyzed the momentum of the outgoing pions and defined their emission angle. The tritons were detected in coincidence with the pions by two methods: a telescope of thin plastic scintillators below 40MeV; or a magnetic spectrometer followed by a series of plastic scintillators for higher energies. The experiment shows two main features: at a fixed four-momentum transfer q 2 , the resonance is shifted towards lower energies, this shift increasing with q 2 ; at a fixed angle, but variable q 2 , the minimum of the charge form factor observed in the elastic scattering of electrons on 3 He does not appear. Calculations explain partly these two effects [fr

The Precision Measurement of the Neutron Spin Structure Function Using Polarized HE-3 Target

Energy Technology Data Exchange (ETDEWEB)

Wang, X

2004-01-05

Using a 48.6 GeV polarized electron beam scattering off a polarized {sup 3}He target at Stanford Linear Accelerator Centre (SLAC), they measured the neutron spin structure function g{sub 1}{sup n} over kinematic(x) ranging 0.014 < x <0.7 and 1 < Q{sup 2} < 17GeV{sup 2}. The measurement gave the integral result over the neutron spin structure function {integral}{sub 0.014}{sup 0.7} g{sub 1}{sup n}(x)dx = -0.036 {+-} 0.004(stat) {+-} 0.005(syst) at an average Q{sup 2} = 5GeV{sup 2}. Along with the proton results from SLAC E143 experiment (0.03 < x) and SMC experiment (0.014 < x < 0.03), they find the Bjorken sum rule appears to be largely saturated by the data integrated down to x of 0.014. However, they observe relatively large values for g{sub 1}{sup n} at low x. The result calls into question the usual methods (Regge theory) for extrapolating to x = 0 to find the full neutron integral {integral}{sub 0}{sup t} g{sub 1}{sup n}(x) dx, needed for testing the Quark-Parton Model (QMP).

Analytical continuous slowing down model for nuclear reaction cross-section measurements by exploitation of stopping for projectile energy scanning and results for {sup 13}C({sup 3}He,α){sup 12}C and {sup 13}C({sup 3}He,p){sup 15}N

Energy Technology Data Exchange (ETDEWEB)

Möller, S., E-mail: s.moeller@fz-juelich.de

2017-03-01

Ion beam analysis is a set of precise, calibration free and non-destructive methods for determining surface-near concentrations of potentially all elements and isotopes in a single measurement. For determination of concentrations the reaction cross-section of the projectile with the targets has to be known, in general at the primary beam energy and all energies below. To reduce the experimental effort of cross-section measurements a new method is presented here. The method is based on the projectile energy reduction when passing matter of thick targets. The continuous slowing down approximation is used to determine cross-sections from a thick target at projectile energies below the primary energy by backward calculation of the measured product spectra. Results for {sup 12}C({sup 3}He,p){sup 14}N below 4.5 MeV are in rough agreement with literature data and reproduce the measured spectra. New data for reactions of {sup 3}He with {sup 13}C are acquired using the new technique. The applied approximations and further applications are discussed.