A novel route is presented enabling minimization of feature sizes via laser ablative micro-patterning in highly porous silica aerogel monoliths and subsequent viscous sintering. Vitrification yields isotropically contracted silica solids preserving their original stereometric forms. The contraction depends on aerogel structure and porosity and we demonstrate here the first realization of a 3:1 ...

Nano-porous silica aerogels are unique materials often having a high specific surface area, a high porosity (75-99%), a low thermal conductivity (0.01-0.03W/mK), and a low index of refraction. Because of their unique properties, aerogels have been extensively studied, not only for use as transparent thermal insulators but also as inter-metal dielectric materials, optical and acoustic applicatio...

Superfluid 3He confined in aerogel offers a unique chance to study the effects of a short mean free path on the properties of a well defined superfluid Fermi liquid with anisotropic pairing. Transport coefficients and collective excitations, e.g. longitudinal sound, are expected to react sensitively to a short mean free path and to offer the possibility for testing recently developed models for...

Measurements of superfluid He in 98% aerogel demonstrate the existence of a metastable A-like phase and a stable B-like phase. It has been suggested that the relative stability of these two phases is controlled by anisotropic quasiparticle scattering in the aerogel. Anisotropic scattering produced by axial compression of the aerogel has been predicted to stabilize the axial state of superfluid ...

The abundances of cosmic-ray helium isotopes between 0.2 and 3.7 GeV nucleon~1 were measured by the Isotope Matter Antimatter Experiment (IMAX) during a Ñight from Lynn Lake, Manitoba, Canada on 1992 July 16È17. The IMAX balloon-borne magnetic spectrometer realized a direct measurement of the charge, the velocity, and the rigidity of cosmic rays using plastic scintillators, a high-resolution ti...

The construction and use of a dual radiator Ring Imaging Čerenkov (RICH) detector is described. This instrument was developed for the HERMES experiment at DESY which emphasises measurements of semi-inclusive deep-inelastic scattering. It provides particle identification for pions, kaons, and protons in the momentum range from 2 to 15 GeV, which is essential to these studies. The instrument uses...

We study the superfluid transition of 4He in aerogel by Monte Carlo simulations and finite size scaling analysis. Aerogel is a highly porous silica glass, which we model by a diffusion limited cluster aggregation model. The superfluid is modeled by a three dimensional XY model, with excluded bonds to sites on the aerogel cluster. We obtain the correlation length exponent nu=0.73+/-0.02, in reas...

The Spin Supercurrent and Bose-Einstein condensation of magnons similar to an atomic BEC was observed in 1984 in superfluid He-B. Recently we discovered 2 new types of BEC in superfluid He in deformed aerogel. The orbital part of the wave function orients along the deformation and changes the magnon-magnon interaction. In some cases it forms a magnon trap. We can do it for He-A by uniaxially co...

Low-refractive index silica aerogel is the most convenient radiator for threshold-type Cherenkov counters, which is used for particle identification in high-energy physics experiments. For the BELLE detector at the KEK B-Factory, we have produced about 2 m of hydrophobic silica aerogels of n = 1.01 1.03 using a new production method. The particle identification capability of the aerogel Cherenk...