Liquid Helium Films

Publications:

  1. Penanen, K., Fukuto, M., Heilmann, R. K., Silvera, I. F. and Pershan, P. S. "Low temperature studies of 4He liquid-vapor interface. Phys. Rev. (to appear Oct. 2000).
  2. Penanen, K., Fukuto, M., Silvera, I. F. and Pershan, P. S. " X-Ray induced thinning of 3He and 3He/4He mixtures. "Phys. Rev. B (to appear Oct. 2000)

People working on the project:

Some relevant data can be found here

AFM data was analyzed using home-made AFM analysis program

Also available is liquid helium 100 liter container calibration

As should be clear from the title, we study thin (about 200 Å) helium films. It is hard to resolve details of their structure by conventional means (visible light), so we use X-Rays (of wavelength ~ 1.5 Å) to achieve our goal. The most common technique that we use is X-Ray Specular Reflectivity. The experiments are performed mainly at the National Synchrotron Light Source, Brookhaven National Lab, but most of the preparation work is done at Harvard, using the Rotating Anode facility. To cool the sample to liquid helium temperatures we use a vapor-cooled helium cryostat named Syncryo (derived from synchrotron and cryostat). The lowest temperature achieved in it was 0.39 K. This temperature is sufficiently low to condense even the lighter helium isotope, 3He.

Have you ever wondered how people ever get to those temperatures? For an interactive show, please follow this link.
Parallel to the show above, here is the detailed cross-linked interactive photo album of the system components.
To learn more about the earlies phases of this work, please look into the relevant publications:

  • Get a postscript version of our abstract in the 1995 BNL annual report.
  • X-Ray Induced Electrostatic Charging of Helium Films.
    K.Penanen, P.S Pershan, M.J. Regan and I.F. Silvera
    Journal of Low Temperature Physics, vol.101, no.3/4, p.489 (1995)
  • L.B.Lurio, T.A Rabedeau, P.S. Pershan and I.F Silvera, Physica B 169, 507 (1990).
  • L.B.Lurio, T.A Rabedeau, P.S. Pershan, I.F Silvera, M. Deutsch, S.D. Kosowsky and B.M. Ocko, Phys. Rev. Lett. 68, 2628 (1992).
  • L.B.Lurio, T.A Rabedeau, P.S. Pershan, I.F Silvera, M. Deutsch, S.D. Kosowsky and B.M. Ocko, Phys. Rev. 48, 9644 (1993).