نتایج جستجو برای: 3He
تعداد نتایج: 1796 فیلتر نتایج به سال:
We study within the Faddeev framework the 3He( e, e′p)d as well as the 3He( e, e′p)pn and 3He( e, e′n)pp reactions in order to extract information on the proton and neutron polarization in polarized 3He. We achieve clear analytical insight for simplified dynamical assumptions and define conditions for experimental access to important 3He properties. In addition we point to the possibility of me...
The 3He(3He, 2p)4He and 3H(3H, 2n)4He reactions are studied in a microscopic cluster model. We search for resonances in the 3He+3He and 4He+p+p channels using methods that treat the twoand three-body resonance asymptotics correctly. Our results show that the existence of a low-energy resonance or virtual state, which could influence the 7Be and 8B solar neutrino fluxes, is rather unlikely. Our ...
In this review we first present an introduction to 3He and to the ROTA collaboration under which most of the knowledge on vortices in superfluid 3He has been obtained. In the physics part, we start from the exceptional properties of helium at millikelvin temperatures. The dilemma of rotating superfluids is presented. In 4He and in 3He-B the problem is solved by nucleating an array of singular v...
The (extended) lowest order constrained variational ((E) LOCV) method was used to calculate the ground state energy of liquid helium 3 (3He) droplets at zero temperature. Different types of density distribution profiles, such as the Gaussian, the Quasi-Gaussian and the Woods-Saxon were used. It was shown that at least, on average, near 20 3He atoms are needed to get the bound state for 3He liq...
3He atoms dissolved in superfluid 4He may form dimers (He)2 in two-dimensional (2D) geometries. We study dimer formation in films of dilute 3He–4He mixture. After designing a schematic 3He–3He interaction potential we calculate the dimer binding energy for various substrates. It is shown that 3He impurity states localized near the substrate give rise to the largest magnitudes of the binding ene...
K. Matsumoto,* J. V. Porto, L. Pollack, E. N. Smith, T. L. Ho, and J. M. Parpia Laboratory of Atomic & Solid State Physics and Materials Science Center, Cornell University, Ithaca, New York 14853 (Received 14 January 1997) We present evidence for a nonzero pressure, T 0 superfluid phase transition of 3He in 98.2% open aerogel. Unlike bulk 3He which is a superfluid at T 0 at all pressures (d...
Ionizing radiation increases the nuclear spin relaxation in the target chamber. Also known as “beam depolarization,” it is essentially a two step process. First, the beam ionizes an 3He atom which results in an free electron and an atomic ion 3He+. There is also the possibility that the atomic ion bonds with an neutral 3He atom to form an molecular ion He2 . Second, interactions with 3He ions i...
Eggleton et al. (Reports, 8 December 2006, p. 1580) reported on a deep-mixing mechanism in low-mass stars caused by a Rayleigh-Taylor instability that destroys all of the helium isotope 3He produced during the star's lifetime. Observations of 3He in planetary nebulae, however, indicate that some stars produce prodigious amounts of 3He. This is inconsistent with the claim that all low-mass stars...
We have investigated the dissipation (Q-1) using the torsion pendulum technique for pure 3He and 3He-4He mixtures in silica aerogel near the 3He superfluid transition (T(c)) in aerogel. With pure 3He the Q-1 decreases at the onset of superfluidity. When phase separated 3He-4He mixtures are introduced into the aerogel, the Q-1 does not decrease as rapidly and eventually increases for the highest...
Because of the lack of a free neutron target, deuterium targets have been used extensively in studying the neutron structure. The unique spin structure of the 3He ground state wave function and the recent developments in laser technologies made polarized 3He targets widely used in many experiments from neutron electromagnetic form factor studies to nucleon spin structure function measurements a...
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