A bright metastable atom source at 80 K

A bright metastable atom source at 80 K

Atom lithography with metastable helium

A bright metastable helium He beam is collimated sequentially with the bichromatic force and three optical molasses velocity compression stages. Each He atom in the beam has 20 eV of internal energy that can destroy a molecular resist assembled on a gold coated silicon wafer. Patterns in the resist are imprinted onto the gold layer with a standard selective etch. Patterning of the wafer with th...

Contamination resists in metastable atom lithography

We have used a metastable argon beam to expose gold-coated silicon substrates covered with a self assembled monolayer (SAM) resist. The substrates have been covered with a patterned mask, with feamres of 10 pm size, and exposed to the atomic beam. Subsequent etching revealed negative contrast patterns, consistent with the formation of a negative contamination resist in the SAM, which we attribu...

A Second Bright Source Detected Near SN1987A

Speckle interferometry observations, made just 30 and 38 days after the explosion of supernova SN1987A (SN) (which was first seen on February 23, 1987), showed evidence for a bright source, separated from the SN by only 60 mas. Reprocessing of that data using new image reconstruction algorithms has resulted in much cleaner images which not only clearly show the bright spot reported in 1987, but...

Spin polarization transfer in ground and metastable helium atom collisions

Cross sections and rate constants for total elastic, diffusion and transfer of metastability for collisions between He(11S)–He(23S) and He(11S)–He(23P) atoms over a wide range of energies and temperatures are presented. The rate constant for spin metastability excitation in He(11S)–He(23P) collision is several orders of magnitude larger than that for He(11S)–He(23S) collision at cold temperatur...